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                                  NOAA STATUS AND TRENDS
                                              Mussel Watch Project
                                          Year 7 Technical Report

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                                                                January 1994






          NOAA NATIONAL
          STATUS AND TRENDS

          Mussel Watch Project

          Year 7 Technical Report



          Prepared by

          The Geochemical and Environmental Research
          Group (GERG)
          Texas A&M University
          833 Graham Road
          College Station, Texas 77845


                                PrOPertY Of CSC Library
          Submitted to
      t   U.S. Department of Commerce
      "Z
          National Oceanic & Atmospheric Administration
        ZS 1305 East-West Hwy.
          Silver Spring, M.D 20910 U - S . DEPARTMENT OF COMMERCE NOAA
         -January 1994
                                   COASTAL SERVICES CENTER
                                   2234 SOUTH HOBSON AVENUE
                                   CHARLESTON , SC 29405-2413

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                                                                     Table of Contents



                    Introduction         ............................................................................................          1-1

                    Reprint 1: The UsejWness of Transplanted Oysters in Biomonitoring
                         Studies      ...............................................................................................       1-11

                    Reprint 2: Overview of the Mrst Four Years of the NOAA National
                         Status and Trends Mussel Watch Program                             ...........................................     1-21

                    Reprint 3: Trace Organic Contamination in Galveston Bay Oysters:
                         Results from the NOAA National Status and Trends Mussel Watch
                         Program       ..............................................................................................       1-31

                    Reprint 4: Indicators of Trace Metal Pollution in Galveston Bay                                     ................    1-37

                    Reprint 5: Oysters as Biomonitors of the APEX Barge Oil Spill.                                     .................    1-45

                    Reprint 6: Meld Studies Using the Oyster Crassostrea virginica to
                         Determine Mercury Accumulation and Depuration Rates                                     .......................    1-53

                    Reprint 7: Trace Metal Chemistry of Galveston Bay: Water,
                         Sediment and Biota.              ............................................................................      1-59

                    Reprint 8: Mercury Bioaccumulation by Shrimp (Penaeus aztecus)
                         Transplanted to Lavaca Bay, Texas                        .....................................................     1-81

                    Reprint 9: Polynuclear Aromatic Hydrocarbon Contaminants in
                         Oystersfirom the GLdf of Mexico (1986-1990)                           ........................................     1-87

                    Reprint 10: Butyltin Concentrations in Oysters from the Gulf of
                         Mexico During 1989-1991                  ....................................................................      1-97

                    Reprint 1 1:The American Oyster (Crassostrea virginica) as a
                         Bioindicator of Trace Organic Contamination                           ........................................    1-109









                  NOAX S NATIONAL STATUS AND TRENDS (NS&T) MUSSEL WATCH
                                     PROGRAM - GULF OF MEXICO


                       The purpose of the NOAA National Status and Trends (NS&T)
                Mussel Watch Project is to determine the long-term temporal and spatial
                trends of selected environmental contaminant concentrations in bays
                and estuaries. The key questions in this regard are:
                       (1) What is the current condition of the nation's coastal zone?
                       (2) Are these conditions getting better or worse?

                       This report represents the Year 7 Technical Report from this multi-
                year project. These questions have been addressed in detail as evidenced
                by the scientific papers and reports that have resulted from the
                Geochemical and Environmental Research Group's (GERG)
                interpretations of the Gulf Coast data (Table 1). Publications not
                included in GERG's previous Technical Reports are contained in this
                technical report.

                       This report is an update on the current condition of the Gulf of
                Mexico coastal zone, based on results from Years 1 through 7 of the
                NOAA NS&T Mussel Watch Project. Following is a brief sampling survey
                of these years:

                        Year 1 -   49 sites (147 stations) of the original 51 sites were
                                   successfully sampled. Sediments and oysters were
                                   analyzed at triplicate stations from all sites.
                        Year 2 -   48 sites (144 stations) of the original 51 sites were
                                   successfully sampled. Sediments and oysters were
                                   analyzed at triplicate stations from all sites.
                        Year 3 -   Twenty (20) sites were added to the original list of 51
                                   sites for a total of 71 sites. Sixty-four (64) sites (192
                                   stations) of the 71 sites were sampled (only 19 of the
                                   new sites were sampled). Oysters were analyzed at
                                   triplicate stations from all sites. Sediments were
                                   analyzed at only the new sites (three stations analyzed
                                   per site).
                        Year 4 -   Seven (7) new sites were added (only six of the new sites
                                   were successfully sampled). Sixty-seven (67) sites (201
                                   stations) of the 78 total sites were sampled. Oysters
                                   were analyzed at triplicate stations from all sites.
                                   Sediments were analyzed at only the new sites (three
                                   stations analyzed per site).
                        Year 5 -   Three (3) new sites were added to the sampling project
                                   (only two of these sites were successfully sampled-,
                                   79:MBDR and 80:PBSP). Sixty-eight (68) sites (204
                                   stations) of the 80 total sites were sampled. Oysters
                                   were analyzed at triplicate stations from all sites.



                                                     1-1









                                    Sediments were analyzed at only the new sites (three
                                    stations analyzed per site).
                         Year 6 -   Two (2) new sites were added to the sampling project
                                    (81:BHKF in Bahia Honda Key, FL and 63:LPGO in
                                    Lake Pontchartrain, LA). Sixty-four (64) sites (192
                                    stations) were sampled. Oysters were analyzed at
                                    triplicate stations from all sites. Sediments were
                                    analyzed at only the new sites (three stations analyzed
                                    per site).
                         Year 7 - Five new sites were established including three new
                                    sites in Puerto Rico (Sites 86 to 88) and two new sites
                                    in Choctawhatchee Bay (Sites 84 and 85). Sixty-seven
                                    (67) sites were analyzed. Only one oyster analysis was
                                    conducted at each of the old sites on a composite from
                                    the three stations. Sediments were analyzed at the five
                                    new sites and one site in Florida (PBPH) (three stations
                                    analyzed per site).

                  Details of the sample collection and location of field sampling sites are
                  contained in a separate report titled "Field Sampling and Logistics in
                  Year 7".

                        The oyster and sediment samples were analyzed for contaminant
                  concentrations [trace metals, polynuclear aromatic hydrocarbons (PAH),
                  pesticides and polychlorinated biphenyls (PCBs)], disease incidence and
                  other parameters that aid in the interpretation of contaminant
                  distributions (grain size, oyster size, lipid content, etc.). The analytical
                  procedures used and the QA/QC Project Plan are detailed in a separate
                  repor-t titled "Analytical Methods". The data that were produced from the
                  sample analyses for Year 7 are found in a separate report titled
                  "Analytical Data".

                        A complete and comprehensive interpretation of the data from the
                  National Status and Trends Project for oyster data coupled with the
                  sediment data is an ongoing process. We have begun and are continuing
                  that process as evidenced by this report and the scientific manuscripts
                  that we have published or submitted for publication (Table 1). As part of
                  the data interpretation and dissemination, over 40 presentations of the
                  NOAA NS&T Gulf Coast Mussel Watch Project were given at national and
                  international meetings. With seven years of data, the question of
                  temporal trends of contaminant concentrations has been addressed. A
                  general conclusion found for most contaminants measured is that the
                  concentrations have remained relatively constant over the seven-year
                  sampling period. This general trend, however, is not observed at all sites.
                  Some sites show significant changes (both increases and decreases)
                  -among the years. Continued sampling is addressing the frequency and
                  rates of these changes.

                        Exceptions to this general trend are found for DDTs and TBT.
                  When historical data for DDT in bivalves is compared to current NS&T


                                                      1-2








                data, a decrease in concentration is apparent. Also based on TBT data
                collected as part of the NOAA NS&T Mussel Watch Project, a decline in
                TBT concentration in oysters is apparent. Both declines may be in
                response to regulatory actions.

                      During Year 3 of this project, 20 new sites were added. These.sites
                were chosen to be closer to urban areas, and therefore, to the sources of
                contaminant inputs. These new sites were not, however, located near
                any known point sources of contaminant input. These sites were added
                to better represent the current status of contaminant concentrations in
                the Gulf of Mexico. Over the subsequent years of the project (Years 4
                through 7) additional sites have been added to increase the
                representative coverage of the Gulf of Mexico and U.S. Caribbean
                territories.

                      While sampling sites for this project were specifically chosen to
                avoid known point sources of contamination, the detection of coprostanol
                in sediment from all sites indicates that the products of man's activities
                have reached all of the sites sampled. However, when compared to
                known point sources of contamination, all of the contaminant
                concentrations reported are, in most cases, many orders of magnitude
                lower than obviously contaminated areas. The lower concentrations in
                Gulf of Mexico samples most likely reflect the fact that the sites are far
                removed from point sources of inputs, a condition which is harder to
                achieve in East and West Coast estuaries. In fact, new sites added in
                Years 3 through 7 are closer to urban areas and generally had higher
                contaminant concentrations. An important conclusion derived from the
                extensive NS&T data set is that contamination levels in Gulf Coast near
                shore areas remain the same or are getting better, and most areas
                removed from point sources are not severely contaminated.

                      This document represents one of three report products as part of
                Year 7 of the NS&T Gulf of Mexico projects. The other two reports are
                entitled:

                      * Analytical Data, Year 7
                      0 Field Sampling and Logistics, Year 7














                                                   1-3










                    Table 1. GERG/NOAA NS&T PUBLICATIONS                                        Included in
                                                                                               Year Report

                    Wade, T.L., B. Garcia-Romero and J.M. Brooks (1988)
                            Tributyltin contamination of bivalves from U.S. coastal
                            estuaries. Environmental Science and Technology, 22:
                            1488-1493.                                                                IV

                    Wade, T.L., E.L. Atlas, J.M. Brooks, M.C. Kennicutt 11, R.G. Fox,
                            J. Sericano, B. Garcia-Romero and D. DeFreitas (1988)
                            NOAA Gulf of Mexico Status and Trends Program:
                            Trace organic contaminant distribution in sediments
                            and oysters. Estuaries, 11: 171-179.                                      IV
                    Wade, T.L., B. Garcia-Romero and J.M. Brooks (1988)                                                 0
                            Tributyltin analyses in association with NOAA's
                            National Status and Trends Mussel Watch Program. In:
                            OCEANS '88 Conference Proceedings, Baltimore, MD, 31
                            Oct. - 2 Nov. 1988, pp. 1198-1201.                                        IV

                    Wade, T.L., M.C. Kennicutt, 11 and J.M. Brooks (1989) Gulf of
                            Mexico hydrocarbon seep communities: III: Aromatic
                            hydrocarbon burdens of organisms from oil seep
                            ecosystems. Marine Environmental Research, 27: 19-30.                     IV

                    Wade, T.L. and J.L. Sericano (1989) Trends in organic
                            contaminant distributions in oysters from the Gulf of
                            Mexico. In: Proceedings, Oceans '89 Conference, Seattle,
                            WA, pp. 585-589.                                                          IV

                    Wade, T.L. and B. Garcia-Romero (1989) Status and trends of
                            tributyltin contamination of oysters and sediments from
                            the Gulf of Mexico. In: Proceedings, Oceans '89
                            Conference, Seattle, WA, pp. 550-553.                                     IV

                    Wade, T.L. and C.S. Giam (1989) Organic contaminants in the
                            Gulf of Mexico. In: Proceedings, 22nd Waterfor Texas
                            Conference, Oct. 19-21, 1988, South Shore Harbour Resort
                            and Conference Center, Lzague City, TX (R. Jensen and C.
                            Dunagan, Eds.), pp. 25-30.                                                V

                    Craig,  A., E.N. Powell, R.R. Fay and J.M. Brooks (1989)
                            Distribution of Perkinsus marinus in Gulf coast oyster
                            populations. Estuaries, 12: 82-91.                                        IV

                    Presley, B.J., R.J. Taylor and P.N. Boothe (1990) Trace metals
                            in Gulf of Mexico oysters. The Science of the Total
                            Environment, 97/98: 551-553.                                              IV








                                                              1-4










                   Sericano, J.L., E.L. Atlas, T.L. Wade and J.M. Brooks (1990)
                          NOAA's Status and Trends Mussel Watch Program:
                          Chlorinated pesticides and PCB's in oysters
                          (Crassostrea virginica) and sediments from the Gulf of
                          Mexico, 1986-1987. Marine Environmental Research, 29:
                          161-203.                                                                 IV

                   Wade, T.L., B. Garcia-Romero and J.M. Brooks (1990) Butyltins
                          in sediments and bivalves from U.S. coastal areas.
                          Chemosphere 20: 647-662.                                                 IV

                   Brooks, J.M., M.C. Kennicutt II, T.L. Wade, A.D. Hart, G.J.
                          Denoux and T.J. McDonald (1990) Hydrocarbon
                          distributions around a shallow water multiwell
                          platform. Environmental Science and Technology, 24:
                          1079-1085.                                                               IV

                   Sericano, J.L., T.L. Wade, E.L. Atlas and J.M. Brooks (1990)
                          Historical perspective on the environmental
                          bioavailability of DDT and its derivatives to Gulf of
                          Mexico oysters. Environmental Science and Technology,
                          24: 1541-1548.                                                           IV

                   Wade, T.L., J.L. Sericano, B. Garcia-Romero, J.M. Brooks and
                          B.J. Presley (1990) Gulf coast NOAA National Status &
                          Trends Mussel Watch: the first four years. In: MTS'90
                          Conference Proceedings, Washington, D.C., 26-28
                          September 1990, pp. 274-280.                                           IV, V

                   Brooks, J.M., T.L. Wade, B.J. Presley, J.L. Sericano, T.J.
                          McDonald, T.J. Jackson, D.L. Wilkinson and T.F. Davis
                          (1991) Toxic contamination of aquatic organisms in
                          Galveston      Bay. In: Proceedings Galveston Bay
                          Characterization Workshop, February 21-23, pp. 65-67.                    VI

                   Wade, T.L. J.M. Brooks, J.L. Sericano, T.J. McDonald, B. Garcia-
                          Romero, R.R. Fay, and D.L. Wilkinson (1991) Trace
                          organic contamination in Galveston Bay: Results from
                          the NOAA National Status and Trends Mussel Watch
                          Program In: Proceedings Galveston Bay Characterization
                          Workshop, February 21-23, pp. 68-70.                                     VI

                   Presley, B.J., R.J. Taylor and P.N. Boothe (1991) Trace metals
                          in Galveston Bay oysters. In: Proceedings Galveston Bay
                          Characterization Workshop, February 21-23, pp. 71-73.                    VI

                   Sericano, J.L., T.L. Wade and J.M. Brooks (1991) Transplanted
                          oysters as sentinel organisms in monitoring studies. In:
                          Proceedings Galveston Bay Characterization Workshop,
                          February 21-23, pp. 74-75.                                               VI




                                                            1-5







                                                                                                                          01




                     McDonald, S.J., J.M. Brooks, D. Wilkinson, T.L. Wade and T.J.
                            McDonald (1991) The effects of the Apex Barge oil spill
                            on the fish of Galveston Bay. In: Proceedings Galveston
                            Bay Characterization Workshop, February 21-23, pp. 85-
                            86.                                                                          VI

                     Wade, T.L., J.M. Brooks, M.C. Kennicutt 11, T.J. McDonald, G.J.
                            Denoux and T.J. Jackson (1991) Oysters as biomonitors
                            of oil in the ocean. In: Proceedings 23rd Annual Offshore
                            Technology Conference, No. 6529, Houston, TX, May 6-
                            9,, pp. 275-280.                                                              V

                     Brooks, J.M., M.A. Champ, T.L. Wade, and S.J. McDonald
                            (1991) GEARS:          Response strategy for oil and
                            hazardous spills. SeaTechnology, April 1991,pp.25-32.                         V

                     Sericano, J.L., T. L. Wade and J.M. Brooks (1991) Chlorinated
                            hydrocarbons in Gulf of Mexico oysters: Overview of
                            the first four years of the NOAA's National Status and
                            Trends Mussel Watch Program (1986-1989). In: Water
                            Pollution: Modelling, Measuring and Prediction. Wrobel,
                            L.C. and Brebbia, C.A. (Eds.), Computational Mechanics
                            Publications, Southampton, and Elsevier Applied Science,
                            London, pp. 665-68 1.                                                    V, VI

                     Wade, T.L., B. Garcia-Romero and J.M. Brooks (1991)
                            Bioavailability of butyltins. In: Organic Geochemistry -
                            Advances and Applications in the Natural Environment.
                            Manning, D.A.C. (Ed.), Manchester University Press,
                            Manchester, pp. 571-573.                                                      V

                     Wilson, E.A., E.N. Powell, M.A. Craig, T.L. Wade and J.M.
                            Brooks (199 1) The distribution of Perkinsus marinus in
                            Gulf coast oysters: its relationship with temperature,
                            reproduction and pollutant body burden. Int. Reuve der
                            Gesantan Hydrobioligie, 75: 533-550.                                         IV

                     Sericano, J.L., A.M. El-Husseini and T.L. Wade (1991) Isolation
                            of planar polychlorinated biphenyls by carbon column
                            chromatography. Chemosphere, 23(7): 915-924.                             V, VI

                     Wade, T.L., B. Garcia-Romero and J.M. Brooks (1991) Oysters
                            as biomonitors of butyltins in the Gulf of Mexico.
                            Marine Environmental Research, 32: 233-:@41.                            IV, V

                     Wilson, E.A., E.N. Powell, T.L. Wade'    R.J. Taylor, B.J. Presley
                            and J.M. Brooks (1991) Spatial and temporal
                            distributions of contaminant body burden and disease
                            in Gulf of Mexico oyster populations: The role of local
                            and large-scale climatic controls. Helgolander
                            Meeresunters, 46: 201-235.                                              V, VI

                     Powell, W.N., J.D. Gauthier, E.A. Wilson, A. Nelson, R.R. Fay
                            and J.M. Brooks (1992) Oyster disease and climate


                                                                1-6









                          change. Are yearly changes in Perkinsus marinus
                          parasitism in oysters (Crassostrea virginica) controlled
                          by climatic cycles in the Gulf of Mexico? PSZNI: Marine
                          Ecology, 13: 243-270.                                                      IV

                   Hofmann, E.E., E.N. Powell, J.M. Klinck E.A. Wilson (1992)
                          Modeling oyster populations III. critical feeding
                          periods, growth and reproduction. J.              Shellfish
                          Research, 2: 399-416.                                                        V

                   Sericano, J.L., T.L. Wade, A.M. El-Husseini and J.M. Brooks
                          (1992) Environmental significance of the uptake and
                          depuration of planar PCB congeners by the American
                          oyster (Crassostrea virginica). Marine Pollution Bulletin,
                          24: 537-543.                                                               VI

                   Wade, T.L., E.N. Powell, T.J. Jackson and J.M. Brooks (1992)
                          Processes controlling temporal trends in Gulf of Mexico
                          Oyster health and contaminant concentrations. In:
                          Proceedings MTS '92, Marine Technology Society, Oct. 19 -
                          21, Washington, D.C. pp. 223-229.                                          VI

                   Tripp, B.W., J.W. Farrington, E.D. Goldberg and J.L. Sericano
                          (1992) International mussel watch: the initial
                          implementation phase. Marine Pollution Bulletin, 24:
                          371-373.                                                                   VI

                   Sericano, J.L., T.L. Wade and J.M. Brooks (1993) The
                          usefulness of transplanted oysters in bionionitoring
                          studies. In: Proceedings of The Coastal Society Twelfth
                          International Conference, Oct. 21-24, 1990, San Antonio,
                          TX, pp. 417-429.                                                       V, VU

                   Wade, T.L., J.L. Sericano, J.M. Brooks and B.J. Presley (1993)
                          Overview of the first four years of the NOAA National
                          Status and Trends Mussel Watch Program.                  In:
                          Proceedings of The Coastal Society Twelfth International
                          Conference, Oct. 21-24, 1990, San Antonio, TX, pp. 323-
                          334.                                                                   V, VU

                   Sericano, J.L., T.L. Wade, E.N. Powell and J.M. Brooks (1993)
                          Concurrent chemical and histological analyses: Are
                          they compatible? Chemistry and Ecology, 8: 41-47.                       V, VI

                   Sericano, J.L., T.L. Wade, J.M. Brooks, E.L. Atlas, R.R. Fay and
                          D.L. Wilkinson (1993) National Status and Trends
                          @4ussel Watch Program: chlordane-related compounds
                          in Gulf of Me3dco oysters: 1986-1990. Environmental
                          Pollution, 82: 23-32.                                                  V, VI


                   Wade, T.L., T.J. Jackson, J.M. Brooks, J.L. Sericano, B. Garcia-
                          Romero and D.L. Wilkinson (1993) Trace organic
                          contamination in Galveston Bay oysters: results from


                                                             1-7










                            the NOAA National Status and Trends Mussel Watch
                            Program. In: Proceedings, The Second State of the Bay
                            Symposium, Galveston, TX, February 4-6, pp. 109-111.                      Vil

                     Presley, B.J. and K.T. hann (1993) Indicators of trace metal
                            pollution in Galveston Bay. In: Proceedings, The Second
                            State of the Bay Symposium, Galveston, TX, February 4-6,
                            pp. 127-13 1.                                                             V101

                     Wade, T.L., T.J. Jackson, T.J. McDonald, D.L. Wilkinson, and
                            J.M. Brooks (1993) Oysters as biomonitors of the APEX
                            barge oil spill. In: Proceedings, 1993 International Oil
                            Spill Conference, Tampa, FL, March 29-April 1, pp. 127-
                            131.                                                                      VI[

                     Palmer, S.J., B.J. Presley, R.J. Taylor and E.N. Powell (1993)
                            Field studies using the oyster Crassostrea virginica to
                            determine mercury accumulation and depuration rates.
                            Bulletin Environmental Contamination Toxicology 5 1:
                            464-470.                                                                  VH

                     Morse, J.W., B.J. Presley and R.J. Taylor (1993) Trace metal
                            chemistry of Galveston Bay: water, sediment and biota.
                            Marine Environmental Research, 36: 1-37.                                  VH

                     Sericano, J.L. (1993) The American oyster (Crassostrea
                            virginica) as a bioindicator of trace organic
                            contamination.     Ph.D. Dissertation, Department of
                            Oceanography, Texas A&M University, 242 p.                                VI[

                     Palmer, S.J. and B.J. Presley (1993) Mercury bioaccumulation
                            by shrimp (Penaeus aztecus) transplanted to Lavaca
                            Bay, Texas. Marine Pollution Bulletin, 26(10): 564-566.                   V11

                     Jackson, T.J., T.L. Wade, T.J. McDonald, D.L. Wilkinson and J.M.
                            Brooks (1993) Polynuclear aromatic hydrocarbon
                            contandnants in oysters from the Gulf of Mexico (1986-
                            1990). Environmental Pollution , 83: 291-298.                         VI, VII

                     Garcia-Romero, B., T.L. Wade, G.G. Salata, and J.M. Brooks
                            (1993) Butyltin concentrations in oysters from the Gulf
                            of Mexico during 1989-1991. Environmental Pollution,
                            81: 103-111.                                                          V1, V11

                     Sericano, J.L., T.L. Wade, B. Garcia-Romero and J.M. Brooks
                            (1994) Environmental accumulation and depuration of
                            tributyltin by the American Oyster, Crassostrea
                            virginica. Marine Biology (submitted).                                      IV

                     Hofmann, E.E., J.M. Klinck, E.N. Powell, S. Boyles, M. Ellis
                            (1994) Modeling oyster populations 11. Adult size and
                            reproductive effort. Journal of Shellfish Research (in
                            press).                                                                      V



                                                               1-8









                   Ellis, M.S., K.-S. Choi, T.L. Wade, E.N. Powell, T.J. Jackson and
                          D.H. Lewis (1994)       Sources of local variation in
                          polynuclear aromatic hydrocarbon and pesticide body
                          burden in oysters (Crassostrea virginica) from Galveston
                          Bay, Texas. Estuaries (in press).                                         VI


                   To be included in Year 8 Technical Report:

                   Kennicutt, M.C. IL T.L. Wade, B.J. Presley, A.G. Requejo, J.M.
                          Brooks and G.J. Denoux (1994) Sediment contaminants
                          in Casco Bay, Maine: inventories, sources and potential
                          for biological effects. Environmental Science and
                          Technology (in press).

                   McDonald, S.J., M.C. Kennicutt IL J.L. Sericano, H. Liu, T.L.
                          Wade and S.H. Safe (1994) Correlation between
                          bioassay-derived P4501A1 -Induction activity and
                          chemical analysis of dam (Laternula elliptica) extracts
                          from McMurdo Sound, Antarctica. M a r i n e
                          Environmental Research (Submitted).

                   Sericano, I.L., T.L. Wade and J.M. Brooks (1994) Accumulation
                          and depuration of organic compounds by the American
                          oyster (Cassostrea virginica). Science q the Total
                          Environment (in press).

                   Sericano, I.L., S.H. Safe, T.L. Wade, and J.M. Brooks (1994)
                          Toxicological significance of non-, mono-, and di-ortho
                          substituted polychlorinated biphenyls in oysters from
                          Galveston and Tampa Bays. Environmental Toxicology
                          and Chemistry (submitted).
























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                     Biomonitoring Studies
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                                                                                                          M M M M M 1111111IN
                                                                                                          The Usefulness or Transplanted Oysters in Biomonitoring Studies

                                                                                                          Jos6 L. Scricano, Terry L. Wade, and James M. Brooks
                                                                                                          Texas A&M University
      The Coastal Society Twelfth International Conference
                                                                                                          Abstract

                                                                                                                 This study was designed to examine, the uptake and depuration of
                                                                                                          selected organic contaminants of environmental concern, i.e., polynuclear
                                                                                                          aromatic hydrocarbons (PAHs) and polychlorinated biphcnyls (PCBs), by
      CONFERENCE                                                                                          transplanted oysters (Crassostrea' virginica) in Galveston Bay, Texas and to
                                                                                                          establish the feasibility of using transplanted oysters for biomonitoring the
                                                                                                          contamination status in areas were no indigenous bivalves are present.
      PROCEEDINGS                                                                                         Transplanted oysters bioaccumulated individual PAHs and low molecular
                                                                                                          weight PCBs to concentrations that were not statistically differentiable from
                                                                                                          the levels encountered in native oysters within 30 to 48 days. In contrast, high
      Our Coastal Experience:
                                                                                                          molecular weight PCBs did not reach equilibrium in transplanted oysters;
      Assessing the Past,                                                                                 whose high molecular weight PCB concentrations were lower than those
                                                                                                          measured in indigenous oysters during the seven-week uptake period. During
      Confronting                  the      Future                                                        the depuration phase of this study, originally uncontaminated oysters
                                                                                                                                                                        aster rate than
                                                                                                          depurated PAHs and low molecular wight PCBs at a f,
                                                                                                          chronically contaminated oysters. Clearance of high molecular weight PCBs
                                                                          4                               was limited in both oyster populations.


                                                                                                          Introduction


                                                                                                                 Contamination of the coastal marine environment by a number of
                                                                                                          organic compounds of synthetic or natural origin has received increasing
                                                                                                          a
                                                                                                          tention over the last several years. Biomonitoring of these compounds in
                                                                                                          t
                                                                                                          the aquatic environment has been well established and bivalves are generally
                                                                                                          preferred for this purpose. The rationale for the "Mussel Watch" approach
                                                                                                          using different bivalves, e.g. mussel, oysters and/or clams, has been
                                                                                                          summarized by different authors (Goldbcrg et aL, 1978; Farrington et A,
                                                                                                          1980; Phillips, 1980; Risebrough et al., 1983) and its concept has been applied
                                                                               ...                        to many monitoring programs during the last decade (Farrington et al., 1983;
                                                                                                          Martin, 1985; Tavares et al., 1988; Wade et al., 1988; Sericano et al., 1990).
                                      r
                                                                                                                 The National Oceanic and Atmospheric Administration's National
                                                                                                          Status and Trends Program (NOAA's NS&T) is designed to monitor the
                                                                                                          current status and long-term effects of selected organic and inorganic
                                                                                                          contaminants of environmental concern, e.g. polynuclear aromatic
                                OCTOBER                   21-2411990                                      hydrocarbons (PAHs), chlorinated pesticides, polychlorinated biphenyls
                                                                                                          (PCBs), and trace metals, along the coasts of the U.S. by measuring their
                                                   St.   Anthony Hotel
                                                                                                          concentrations in bivalves over a number of years. During the first five years
                                                San      Antonio, Texas                                   of this program (1986-1990), the intent was to sample all the locations

                                                                                                                                             417





               prescribed by NOAA. However, locations depleted or devoid of living oysters                        in native oysters represent the time-integrated contaminant concentrations
               caused by virtue of diseases, predators, excessive freshwater runoff, harvesting,                  available to the oysters in solution, adsorbed onto particles, and incorporated
               or dredge material burying entire reefs compromised this goal. Therefore, in                       into food.
               some instances, it was not possible to obtain samples. After the first five
               years of the NS&T, nearly 20% of the original locations presented some of                                     Initial concentrations of total PAHS in transplanted oysters increased
               the above-mentioned sampling problems that left the database with missing                          from 290 ng/g to a final value of 4360 ng/g. Two- and three-ring PAHs were
               values. Transplantation of bivalves to areas where indigenous individuals were                     detected in low concentrations in transplanted and indigenous oysters. Four-
               not originally present or have been lost because of natural or man-induced                         and five-ring compounds were accumulated to the highest concentrations in
               actions could be a potentially useful tool in monitoring environmental                             Hanna Reef oysters. By the end of the first 48 days, transplanted oysters
               pollution.                                                                                         accumulated these PAHs to levels that were not statistically differentiable
                                                                                                                  from the concentrations measured in native individuals (Figure 2a). The
                         The present study was designed to examine the uptake and                                 PAHs accumulated to the highest concentrations by transplanted oysters were:
               depuration of selected organic contaminants, i.e. polynuclear aromatic                             pyrene> fluoranthene> chrysene> benzo(e) pyrene> benzo(b)-anthracene
               hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), in oysters                               (Figure 2b). Clams and mussels exposed to sediments contaminated with high
               (Crassostrea virginic ) through transplantation experiments in two locations                       PAH concentrations accumulated pyrene> bcnzo(e) pyrene> benzo(b)
               in Galveston Bay, Texas.                                                                           fluoranthene> benz(a) anthracene (Obana et al., 1983) and chryscnc>
                                                                                                                  benzo(b) fluoranthene> fluoranthene> benzo(e)pyrene> benz(a)anthracene
               Materials and Methods                                                                              (Pruell et al., 1986), respectively.
                         Experimental design                                                                                 Hanna Reef and Ship Channel oysters showed statistically significant
                                                                                                                  depuration (p<0.05) of four- and five-ring PAHs after relocation to the
                         Approximately 250 oysters of similar dimensions were collected from                      Hanna Reef area (Figures 2c and 2d).                Depuration of these aromatic
               a relatively uncontaminated area in Galveston Bay, Hanna Reef, and                                 compounds by both groups of oysters was approximately exponential. This is
               transplanted in 24x7O cm net bags, containing 25-30 individuals per bag, to a                      indicated in Figure 3, where the concentration of selected PAHs plotted on
               new location near the Houston Ship Channel in the upper part of the Bay                            a semi-log plot approximate straight lines.
               (rigure 1). Composite samples of 20 transplanted and. 15 indigenous oysters                                   Kinetics parameters describing uptake and release of PAHs can be
               were collected at 0, 3, 7, 17, 30, and 48 days during the First phase of the
               transplantation experiment. The remaining Hanna Reef oysters were then                             calculated assuming the first-order equation
               back- transplanted to their original location in Galveston Bay. At the same
               time, approximately 150 indigenous oysters from the Ship Channel site were                                    (1) dCt/dt = kuC. - kdCt
               also transplanted to the Hanna Reef area. Composite samples of 20 oysters                          where Ct is the PAH concentration in the transplanted oyster at timc=t, C,,,
               from each population were collected at 3, 6, 18, 30, and 50 days after                             is the PAH concentration in the seawater, and k and k are the uptake and
               transplantation.                                                                                                                                          U        d
                                                                                                                  depuration rate constant, respectively. If the C,,, at Hanna Reef is regarded
                         Analytical method                                                                        as zero, i,e., CW=O, which is considerably reasonable because of the very low
                                                                                                                  PAH concentrations measured in indigenous oysters, then equation (1)
                         The analytical procedures used during this study are modifications of                    reduces to
               previously reported methods (MacLeod et al., 1985) and are fully described                                    (2) dC,/dt      -k
               elsewhere (Wade et al., 1988; Sericano et al., 1990).                                                                           A
               Results and Discussion                                                                             or, after  integration,
                         The concentrations of some of the organic contaminants increased                                    (3) log C,     log C,-(kd/2.301)t
               dramatically during the seven-week exposure period.                    Comparatively,              where CO is the PAH concentration in oysters at the time of their relocation
               concentrations of individual PAHs and PCBs in indigenous oysters during the                        to the Hanna Reef area. Using this equation and the PAH concentrations
               first phase of this experiment were fairly constant. The analyte concentrations
                                                  NW1 8M                M                                M                     M          M          UK 1 9M               M          M



                corresponding t     t"oyster rPU9      ns during the depuration period, values               study, the biological half-lives of PCBs increased with the number of chlorine
                               o bo                atio       I
                of kd can be calculated. Statistical analyses, at the a=0.05 level, of the                   atoms in the biphenyl rings. Langston (1978) also reported that the less
                regression lines of the logarithm of the concentrations versus sampling time                 chlorinated PCB congeners were depurated more rapidly by bivalves
                for the depuration period showed significant differences between the slopes,                 (Cerastoderma edule and Macoma balthica) with half-lives from 5 to 21 days
                i.e., depuration rates, measured for Hanna Reef and Ship Channel oysters.                    for di- to tetrachlorobiphenyls. In contrast, hexachlorobiphenyls, and some of
                                                                                                             the pentachlorobiphenyls, did not decrease in concentration during the 21-day
                        The biological half-life, tj/2, can be derived from equation (3)                     study.    Courtney and Denton (1976) reported that environmentally
                                                                                                             contaminated clams and clams exposed to Aroclor 1254 in the laboratory did
                        (4) t112 = 0.693/kd                                                                  not depurated PCBs during three months in. control seawater.
                        The half-lives are reported in Tablel. They ranged from 10A and                               In summary, PAHs and -low molecular weight PCBs were rapidly
                12.4 days for pyrene to 25.6 and 38.5 days for fluoranthene in Hanna Reef and                accumulated by transplanted oysters. Apparent steady-state concentrations
                Ship Channel oysters, respectively.      Most -of the values were, however,                  were reached after 30 to 48 days. In contrast, high molecular weight PCBs
                between 10 and 16 days.                                                                      did not reached an equilibrium plateau within the sevcn-week exposure to
                                                                                                             high PCB concentrations.         However, the still- increasing concentrations
                        Recently, Pruell ct al. (1986) reported the half-lives for selected                  measured for these PCBs by the end of the exposure period seems to indicate
                PAHs in mussels (Mytilus edulis) exposed to environmentally contaminated                     that, given enough time, equilibrium concentrations will eventually be reached.
                sediments. The calculated half-lives compared well with the values measured                  When back-transplanted to the Hanna Reef area, originally uncontaminated
                in this study (Table 1).                                                                     and chronically exposed oysters depurated PAHs with half-lives ranging from
                                                                                                             10.4 to 23.6 days and from 12.4 to 38.5 days, respectively. These rates were
                        PCB concentrations in transplanted oysters increased from 30 ng/g                    similar to those calculated for tri- and tetrachlorobiphenyls but faster than
                to 850 ng/g after the 48-day exposure period. Pentachlorobiphenyls-were the                  those estimated for heavier molecular weight PCBs. Despite the limitations
                compounds accumulated to the highest concentrations in transplanted and                      discussed in the text, transplanted oysters are considered valuable
                native oysters (Figures 4a and 4b). In comparison, practically no octa-, nona-,              bioindicators of environmental contamination by PAHs and PCBs in areas
                or decachlorobiphenyls were detected in either oyster group.. Contrasting with               lacking indigenous bivalves.
                PAHs, not all the PCB bomologs measured in transplanted oysters reached
                the concentration encountered in indigenous individuals by the end of the first              Acknowledgements
                phase of this experiment.      While there were no statistically significant
                differences in the tri- and tetrachlorobiphenyl concentrations measured in                            Funding for this research was provided by the National Oceanic and
                transplanted and native oysters, significant differences were observed in the                Atmospheric Administration Grant Number 50-DGNC-5-00262 (National
                total concentrations of penta- and hexachlorobiphenyls. It seems evident that                Status and Trends Program).
                a longer exposure period is needed for the higher molecular weight PCBs to
                reach an steady state concentration (Figure 5).

                        Hanna Reef and Ship Channel oysters showed statistically significant
                depuration (p<0.05) of low molecular weight PCBs when relocated to the
                Hanna Reef area (Figures 4c and 4d). Originally uncontaminated oysters
                depurated PCBs at a faster rate than chronically contaminated oysters. The
                dcpuration rates of high molecular weight PCBs were significantly slower in
                both oyster populations. This differential PCB depuration can be observed in
                Figures 4b and 4d showing the concentrations of selected PCBs at the end of
                the uptake and depuration periods. Biological half-lives for these PCBs in
                Hanna Reef and Ship Channel oysters ranged from 21 to 129 days and from
                20 days to >year, respectively (Table 1).        Pruell et al. (1986) reported
                half-lives for tri- to hexacblorobiphenyls in mussels exposed to resuspended
                contaminated sediments ranging from 16.3 to 45.6 days. Similar to the present


                                                      420                                                                                           421





References
														Wade, T.L. Atlas, J.M. Brooks, M.C. Kennicutt II, R.G. Fox, J.L.
Courtney, W.A.M. and G.R.W. Denton.  1976. Environ. Pollut. 10:55-64          	Sericano, B. Garcia-Romero, D. DeFreitas.  1988.  Estuaries, 11:171-179.

Farrington, J.W., J. Albaiges, K.A. Burns, B.P. Dunn, P. Eaton, J.L. Laseter,
P.L. Parker, and S. Wise.  1980.  In: The International Mussel Watch:  Report
of a workshop sponsored by the Environmental Studies Board Commission on
Natural Resources.  National Research Council, pp. 7-77.

________, E.D. Goldberg, R.W. Riserbrough, J.H. Martin, and V.T. Bowen.
1983.  Environ. Sci. Technol.  17: 490-496.

Goldberg, E.D., V.T. Bowen, J.W. Farrington, G. Harvey, J.H. Martin, P.L.
Parker, W. Risebrough, E. Schneider, and E. Gamble.  1978.  Envir.  Conserv.
5: 1-25.

Langston, W.J. 1978.  Mar. Biol., 46: 35-40.

MacLeod, W.D., D.W. Brown, A.J. Friedman, D.G. Burrows, O. Maynes,
R.W. Pearce, C.A. Wigren, and R.G. Bogar.  1985 In:  Standard Analytical
Procedure of the NOAA National Analytical Facility, 1985-1986.  Extractable
Toxic Organic Compounds.  (2nd Ed.), U.S. Department of Commerce,
NOAA/NMFS.  NOAA Tech. Memo.  NMFS F/NWC-92.

Martin, M.  1985.  Mar. Poll. Bull.  16:  140-146.

Obana, H., S. Hori, A. Nakamura, and T. Kashimoto.  1983.  Water Res.,  17:
1183-1187.

Phillips, D.J.H.  1980.  "Quantitative Biological Indicators,  Their Use to
Monitor Trace Metals and Organochlorine Pollution;"  Applied Science:
London.

Pruell, R.J., J.L. Lake, W.R. Davis, and J.G. Quinn.  1986.  Mar. Biol., 91:
497-507.

Risebrough, R.W., B.W. de Lappe, W. Walker II, B.R.T. Simoneit, J.
Grimalt, J. Albaiges, J.A. Garcia Regueiro, I. Ballester A. Nolla, and M.G.
Marino Fernandez.  1983.  Mar. Poll. Bull., 14: 181-187.

Tavares, T.M., V.C. Rocha, C. Porte, D. Barcelo, and J. Albaiges.  1988.  Mar.
Poll. Bull., 19: 575-578.

Sericano, J.L., E.L. Atlas, T.L. Wade, J.M. Brooks.  1990.  Mar.  Environ.  Res.
29: 161-203.

 
                                422











          TABLE 1.        Biological half-lives of selected PAIis and PCBs In transplanted and
                          Indigenous oysters
                                                                                                                                                                                                      T E X A S
                        ----------------------             0-Y-S-T-E-R-S ------------------------
                                                                                           MUSSELS1
                                             HANNA REEF
                                                                    SHIP CHANNEL

             -----------------------------------------------------------
              enan
                  threne                             -


           yrene
          Fluoranthene                             25.6                    38.5                  29.8
          P                                        10.4                    12.4                                                  LA PO
          Benzo(a)alithracene                      13.2                    15.3                  17'.8                                                              -t 'F@
          Chrysene                                 12.3                    15.8                  14.2
          Benzo(e)pyrene                                                                                                                              Q
                                                   11.5                    16.1                  14.4

          PCB#26                                     21
                                                                             20
          PCB#52                                     28                                                                                                     VC,
          PCB#110                                                            47
                                                     45                    147
          PCB# 118                                   75                  >year                                                                                  0
          PCB# 149                                 129                   >year
                                                                                                                                                                                      EA S
          PCB#22                                                                                 16.3                       '291JO,
          PCB#101                                                                                27.9                                           SAN L
          PCB# 128
                                                                                                 36.5
          PCB# 153                                                                               45.6

                               ------------------------------------------------



                                                                                                                                                  TEXAS CITY







                                                                                                                                                                           GALVESTON






                                                                                                                                           A

                                                                                                                                                                           Site 1: Hanna Reef

                                                                                                                             w
                                                                                                                                                                           Site 2 :          Ship Channel



                                                                                                                                        Figure 1: Galveston Bay transplantation sites.







                                                          424
                                                                                                                                                                      425


















                                                                         END OF UPTAKE PERIOD                                 END OF DEPURATION PERIOD

                                                                                    a Ime"t-                     C                           0 ItFtC"I-
                                                 z                                  U fic 07.1                                                  SC OY0...



                                                 z
                                                                                                          z
                                                                                                          b)
                                                 z                                                        U
                                                 0                                                        z
                                                                                                          0  100




                                                           2       3       4                                       2        3       4                0

           4-1                                                     NUMBER OF RINOS                                          NUMBZR  OF RINGS


                                                                         END OF UrrAKE PERIOD                                END OF DEPURATION PERIOD
                                                    2@  b                                                       d


                                                 z
                                                                                                          0

                                                    Iwo


                                                 hi                                                       bi
                                                 U
                                                                                                          0  40
                                                 U                                                        U
                                                                                                             2:
                                                      0                                                                                           AR
                                                                                                                   1      5      3      4       6     6

                                                                       ANALYTE                                                  MIALYTE


                                                 Figure &    Total and selected individual polynuclear aromatic hydrocarbon
                                                             concentrations (ng/g, dry weight) in Hanna Reef and Ship Channel oysters
                                                             after the uptake and depuration periods. The error bars represent one
                                                             standard deviation from the mean (n=4).












                                                                            PYRFNE                                                                CIIRYSENE
                                                                                                 100007
                          LOO@                                                                                                              @ 1IR oysters
                                                                      ---0- 11ROyi(cre                                                      @ &C oysters
                                                                             &C Oysters


                      2    1000                                                                   1000,


                      z

                                                                                                   zoo
                      z     100
                      0



                                                                                                                            UPTAPLZ - DEPuRATION
                                                    UPTAKE   DEPURATION                             10
                             101
                               0     10    20    30   40     so   so    70    Do    90   100          0      10  20    30    40    so    80     70   so     90  too
                                                                                                       rA111'.1111ZIA-101
                                                      juLLkN  DATE                                                           JML" DATE



                                   Eigur
                                            a: Selected PAH concentrations (ng/g. dry weight) in Hanna Reef and Ship
                                                  Channel oysters during the uptake and depuration phases of the experiment.











                                                                                       END OF UPTAKE PERIOD                                            END OF DEPURATION PERIOD

                                                                                                                                        C                                 a ial

                                                                                                     F3 &C oy.t-.                                                             SC 07-t--

                                                         0                                                                     0



                                                         z                                                                     r
                                                         63
                                                         U
                                                         z                                                                     z
                                                                                                                               0
                                                                                                                               U
                                                               o                                     En                              o
                                                                                                       7                                   s       4        5       4         7       a

                                                                                     HOMOLOO                                                               HOMOLOG


             4@h                                                                       END OF UPTAKE PERIOD                                            END OF DZPURATIOM PERIOD
             N)                                                   b                                                                     d
             00

                                                         z                                                                     z
                                                         0                                                                     0
                                                         r
                                                                                                                                    40

                                                         z                                                                     z
                                                                                                                               63   4
                                                         z                                                                     z
                                                                                                                               0
                                                              so                                                                                                          MM M
                                                               0
                                                                   2.(,)    92M      ILO(G) 116(s)   149(a)   ls@m                       20(31    92M     110(a)  &1*($)   14"61    IGTM

                                                                                     ANALYTE                                                               ANALYTE


                                                           Figure 4       Homolog and selected individual polychlorinated biphenyl concentrations
                                                                          (ng/g, dry weight) in Hanna Reef and Ship Channel oysters after the uptake
                                                                          and depuration periods. The error bars represent one standard deviation
                                                                          from the mean (n=4).














                               100                                                        PCB 152                    1000                                                       PCB #110
                                                                                           HR OyVteM                                                                              KROystexe
                                                                                              Oysters
                                                                                                                                                                                  SC Oysters


                         0
      to
      (D


                                10
                         z
                         94
                         U
                         z
                         0                                                                                             to
                         U




                                                            VVTAJM        DI[PURATION
                                                                                                                                                    VPTMM    -   DEPURATION
                                  0      10     20       30    40     so     go      70    so       90                   0      10     20     30      40     6.0    so      7 .0  so      90     too
                                                              JULIAN DATE                                                                            JULIAN DATE

                              D=M-5: Selected PCB concentrations (ng/g, dry Weight)in Hanna Reef and Ship
                                                 Channel oysters during the uptake and depuration phases of the experiment.
                                                                                           sc


















                           Reprint 2

          Overview of the First Four Years of the NOAA
                  National Status and Trends
                     Mussel Watch Program


           Terry L. Wade,, Jos6 L. Sericano,, James M.
                  Brooks, and Bobby J. Presley


















                              1-21






                                                                                                        Overview of the First Four Years of the NOAA National Status and Trends
                                                                               0                        Mussel Watch Program
                                                                                                        Terry L. Wade, Jose L. Sericano, James M. Brooks, and Bobby J. Presley
                                                                                                        Texas A&M University
     The Coastal Society Twelfth International Conference
                                                                                                        Abstract

                                                                                                                 oysters are utilized as bioindicator organisms to characterize the
                                                                                                        current status and long-term trends for 13 trace elements and 57 organic
                                                                                                        contaminants from 75 Gulf of Mexico sampling sites. Sampling sites are
     CONFERENCE                                                                                         distributed throughout the U.S. waters of the Gulf of Mexico, away from
                                                                                                        known point sources of input, and are sampled yearly in the winter to provide
                                                                                                        a geographical description of the chronic contaminant loading of the entire
     PROCEEDINGS                                                                                        U.S. Gulf on a regional basis. Three stations at each site are analyzed
                                                                                                        individually to assess natural intra-site variability so that significant changes
     Our Coastal Experience:                                                                            can be detected. Extensive intercomparison exercises assure the comparability
                                                                                                        of analytical measurements with companion studies on the East and West
     Assessing the Past,                                                                                Coasts. The first four years of data for the Gulf of Mexico represents over
                                                                                                        40,000 individual data points. The general trend from this large data set is
     Confronting                  the       Future                                                      contaminant concentrations that show no changes during the four-year
                                                                                                        sampling period. There are, however, certain sites that have experienced
     :ZK@                                                                                               significant changes in contaminant concentration over the last four-year
                0                                                                                       sampling period, including monotonic increases and decreases. Generally, the
                                                                                                        concentrations of the various contaminants do not show any significant
                                                                                                        relationship to each other. This is probably due to different input sources.
                                                                                                        Higher concentrations of most contaminants are associated with proximity to
                                                                                                        large urban areas.     Two areas that appear to be exceptions to this
                                                         k                                              generalization, St. Andrew Bay, FL and Choctawhatchee Bay, FL, are
                                                          V1%                                           discussed in more detail.


                                                                                                        Introduction

                                                                                                                 The National Oceanic and Atmospheric Administration (NOAA)
                                                                                                        National Status and Trends (NS&T) Mussel Watch Program has sampled and
                                                                                                        analyzed bivalves from U.S. coastal areas since 1086. This report summarizes
                                                                                                        the first four years of NS&T data for the Gulf Coast of the U.S. Sampling
                                                                                                        sites give coverage of the Gulf Coast from southernmost Texas to
                                                                                                        southernmost Florida. Portions of the data have been previously discussed
                                                                                                        (Wade et al., 1988, 1989, and 1990; Wade and Sericana, 1989; Sericano et al.,
                                                                          .!7   to                      1990a and b) and only an overview is presented here.

                                                                                                        Methods
                               OCTOBER                    21-24,1990
                                                                                                                 The NS&T program utilizes standard operating procedures and a
                                                   St.   Anthony Hotel                                  strong quality assurance/quality control program for trace element and trace
                                                San Antonio, Texas
                                                                                                                                             323





                                                                                                                    we have, there is no correlation between As concentration in oysters and
                 organic analyses. Details of these methods arc found elsewhere           (Brooks et                phosphate rock occurrence, shipping, or mining. The As distribution does
                 A, 1989; Wade ct al., 1988). The accuracy and precision of these methods                           seem to be controlled by local environmental inputs, as do certain other metal
                 have been established by several intercalibration exercises conducted by the                       distributions. There seems to be no other explanation for high and low
                 U.S. National Institute of Standards and Testing and the Canadian National
                 Research Council.                                                                                  concentrations of trace metals to occur at adjacent sites, often in a given bay,
                                                                                                                    and to have these patterns consistent from year to year.
                 Results and Discussion                                                                                       Mercury (Hg) is generally enriched in Florida sites (Figure 3), where
                                                                                                                    12 of the 25 sites are well above average. The oysters from Old Tampa Bay
                         Exact sample location and the years in which samples were collected                        are especially high in Hg, rivaling even those from Lavaca Bay, Texas which
                 at each site are presented elsewhere (Wade et al., 1990). The geographical                         are known to be contaminated with Hg and where harvesting of oysters has
                 distribution for selected @ contaminants or suite of contaminants is shown in                      been limited because of the potential threat to human health.
                 Figures 1 to 7. The sites are listed in geographical sequence starting with the
                 southernmost Texas site and continuing along the coast to the southernmost                                   Silver (Ag) distribution (Figure 4) was more     .similar to that of Se than
                 Florida site. The smaller bars on Figures 1 to 4 represent "plus one standard                      to As,    being somewhat enriched in Texas relative to Florida. The most
                 deviation".                                                                                        interesting feature of the Ag distribution is the low values in central Louisiana.
                         Trace metal concentrations in oysters varied considerably from site                        This same pattern was seen for cadmium (Cd) and is somewhat surprising
                 to site; in general, these variations were consistent over the four-year period.                   because central Louisiana Bays have been extensively disturbed by oil
                                                                                                                    exploration activities and are immediately downstream of the Mississippi River
                 That is, the same sites showed consistently above or below average                                                                  I
                 concentrations each year, The high concentrations, with very few exceptions,                       outflow. In this area, then, intense activities by man does not seem to be
                 could not be shown to be associated with known activities of man, such as the                      influencing trace metal concentrations in oysters.
                 presence of industry or oil well drilling operations. However, the fact that                                 The regional geographical distribution of the concentration of the sum
                 high values were often found in only one part of a particular bay (e.g., Tampa                     of 18 individual polyaromatic hydrocarbons (PAHs) (Wade et al., 1988) is
                 or Galveston Bay) while at other nearby sites in these same bays the                               shown in Figure 5. The concentration of PAHs for regional sites are plotted
                 concentrations were average or below for trace metals, suggests localized                          as the average. For example, for Galveston Bay 6 sites are averaged.
                 inputs of these metals.
                          Regional trends in trace metal concentrations in oysters arc more                                   Two PAHs, fluoranthrene and pyrene, generally account for more
                 likely to be due to geologic or climatic factors than to activities of man.                        than 25% of the t      *otal amounts detected. The predominance of these
                 Regional trends can be seen for only a few of the 13 metals assessed and,                          compounds would suggest the major source of PAHs is probably combustion
                 even for these, large site-to-site variations are superimposed on rather subtle                    and not oil seeps or oil spills. In general, higher PAH concentrations are
                 regional trends. For example, Figure 1 shows the distribution of selenium                          found at major river mouths where you also generally rind large urban areas
                 (Se) for the entire Gulf Coast. A gradual decrease in concentration is                             and associated industrial complexes. This is not surprising, since urban runoff
                 apparent when concentrations from Texas and Louisiana are compared to                              and sewage treatment plants are well known chronic sources of PAHs.
                 those in south Florida, even though some high values are found in northern                                   The Panama City and St. Andrcv/s Bay regions are exceptions to this
                 Florida.                                                                                           trend. Their is no major river in these locations, yet they have the highest
                          Arsenic (Figure 2) is usually thought to be chemically similar to Se,                     PAH concentrations. It is possible that these sites were affected by an
                 but it shows a distribution pattern almost opposite to that of Se (Figure 1).                      episodic input of petroleum -(i.e., spill). The hydrocarbon distribution at
                 Arsenic (As) is much higher in some of the Florida oysters than elsewhere on                       these sites indicates they may be contaminated by used crank case oil.
                 the Gulf Coast, yet some Florida oysters, for example those from most sites                                  An extensive interpretation of the chlorinated pesticide and
                 in Tampa Bay, had very low arsenic concentrations all four years. Only the                         polychlorinated biphenyl (PCB) data has been published elsewhere (Wade and
                 Tampa Bay site at Navarez Park near the city of St. Petersburg was                                 Sericano, 1989; Wade et al., 1988 and 1990; Scricano ct.al., 1990a and b).
                 significantly enriched in As. Even the new site at Knight Airport on the edge                      T o t a I    DDT         ( s u in    o, f   o - p'D D E + p - p'D D E + o -
                 of the city of Tampa was low in As. It is possible that the extensive phosphate                    p'DDD+p-pDDD+o-p'DDT+p-p'DDT) regional distribution for oyster
                 rock deposits in Florida are a source of arsenic, but, based on the limited data
                 M                     M          M 32M                 M          M          M                     Ml                                                                                       M





               samples collected along (lie U.S. Gulf of Mexico coast is shown in Figure 6.                  REFERENCES
               Total DDT is the most abundant chlorinated pesticide found in Gulf of
               Mexico oysters. Most of the DDT is present as the metabolites, DDE and                        Brooks, J. M., T.L. Wade, E.L. Atlas, M.C. Kennicutt 11, BJ. Presley, R.R.
               DDD. Less than 10% of the total contaminant load in oysters is the parent                     Fay, E.N. Powell, and G. Wolff. 1989. Analyses of Bivalves and Sediments for
               compound, DDT.                                                                                Organic Chemicals and Trace Elements from Gulf of Mexico Estuaries.
                                                                                                             Annual Report 1989, 678 pp.
                       The regional distribution of total DDT shows that four of the five
               highest concentrations are associated with major river outfalls including the                 Sericano, J.L., E.L. Atlas, T.L. Wade, and J.M. Brooks, 1990a. NOAA's
               Brazos, Mississippi, Mobile, and Choctawatchee Rivers. There were also                        Status and Trends Mussel Watch Program: Chlorinated pesticides and PCB's
               relatively high total DDT concentrations at St. Andrews Bay and Panama                        in oysters (Crassostrea yLirginica) and sediments from the Gulf of Mexico,
               City, although no major rivers are found there. These are the same regions                    1986-1987. Marine Environmental Research, 29: 161-203.
               where the PAHs were the highest. DDTs associated with soils may be
               transported downstream and collect in estuaries. This process provides a                                 T.L. Wade, E.L. Atlas,        and J.M. Brooks, 1990b.         Historical
               plausible explanation of the higher total DDT associated with major river                     perspective on the environmental bioavailabitity of DDT and its derivatives to
               outfalls. The contin ued use of DDT in Mexico and other Latin American                        Gulf of Mexico oysters.        Environmental Science and Technology, 24:
               countries and its atmospheric transport and deposition to the sampling areas                  1541-1548.
               is another possible source.
                                                                                                             Wade, T.L., E.L. Atlas, J.M. Brooks, M.C. Kennicutt 11, R G. Fox, J.
                       The regional distribution of PCBs is shown in Figure 7. PCBs were                     Sericano, B. Garcia-Romero, and D. Defreitas. 1988. NOAA Gulf of Mexico
               detected in all NS&T oyster samples analyzed from Gulf of Mexico waters.                      Status and Trends Program:         trace organic contaminant distribution in
               The highest regional concentration was in St. Andrew's Bay. As mentioned                      sediments and oysters. Estuaries, 11: 171-179.
               before for PAH and total DDT, this is an anomalous station and at present
               we do not know The reason for the high concentrations at this site. Possible                             and J.L. Sericano. 1989 Trends in contaminant distribution in
               sources of contaminants at this site may be nearby oil storage tanks and a                    oysters from the Gulf of Mexico. Pages 585-589 In: Proceedings of the
               paper/pulp mill. The PCB concentrations do not show much difference on                        Oceans'89 Conference, Sept. 18-21,1989, Seattle, WA, Organotin Symposium,
               a regional basis. All the regions have average concentrations within a factor                 Vol. 2.
               of 5.  There are somewhat higher concentrations near areas of higher
               population density (i.e., Galveston Bay, Mobile Bay, etc.).                                   -, J.L. Sericano, B. Garcia-Romero, J.M. Brooks, and BJ. Presley,
                                                                                                             1990. Gulf Coast NOAA National Status & Trends Mussel Watch: The first
               Conclusions                                                                                   four years. Pages 274-280 In: Proceedings, Marine Technology Society '90,
                                                                                                             Washington, D.C., 1990.
                       Most of the    contaminants monitored by the Status and Trends
               Program have relatively long environmental half-lives. These contaminants,
               in general, show no change in environmental concentrations over the first four
               years of this study as seen in the standared deviation for trace metals (Figures
               1 to 4). There are specific sites that are exceptions to this general trend and
               they merit further detailed examination.

               Acknowledgements

                      Funding for this research was provided by the National Oceanic and
               Atmospheric Administration Grant Number 50-DGNC-5- 00262 (National
               Status and Trends Mussel Watch Program).



                                                                                                                                                   327
                                                   326












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                                                     MBLR                                                                                                                                                                  MBGP
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                                                     MBD I                                                                                                                                                                 MBTP
                                                     HBEM                                                                                                                                                                  KBDI
                                                     BF(CL                                                                                                                                                                 KBEM
                                                     BRFS                                                                                                                                                                  BRCL
                                                     GBCR                                                                                                                                                                  BRFS
                                                     GBOB                                                                                                                                                                  GBCR
                                                     GBTD       I.......",", . . . . . . . . .                                                                                                                             GBOB
                                                     GBYC                  . . . . . . . . . .                                                                                                                             G!)TD
                                                     GBSC                                                                                                                                                                  cayc
                                                     GBHR                                                                                                                                                                  CBSC
                                                     S-.                                                                                                                                                                   GBHR
                                                     CLSJ                                                                                                                                                                  SLBB
                                                     CLLC                                                                                                                                                                  CLSJ
                                                     JHJH                                                                                                                                                                  CLLC
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                                                     ABOB                                                                                                                                                                  VBSP
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                                                     BBMB                                                                                                                                                                  BBSD
                                                     MRTP       z                                                                                                                                                          BBMB
                                                                                                                                                                                                                           MRTP
                                                     MRPL                                                                                                                                                      cn
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                                                     ssac                                                                                                                                                                  BSSI    -
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                                                     MSPC                                                                                                                                                                  LBNO
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                                                                                  C)                                                           (P      C)      Cn       C)      Cn
                                                                                  (D                                                   (D      CO      CD      (Z)              C)
                                                            C)                    CD
                                                                                                                  Laguna Madre      (2)
                    Laguna Madre 2)                                                                                                 (2)
                                     ' )                                                                         Corpus Christi     (3)
                   Corpus Christi    (3                                                                                                                                   1-3
                                                                                                                    Aransas   Bay   (2)
                      Aransas  Bay   (2)                                                                                                                                  0
                                                                                                                     Copano Bay (1)
                       Copano  Bay (1)                                                                              Mesquite  Bay   (1)
                     Mesquite  Bay   (1)                                       0
                 San Antonio   Bay   (2)                                                                       San Antonio    Bay   (2)
                                                                                                             Espiritu Santo   Bay   (2)                                   tZI t:1
              Espiritu Santo   Bay   (2)                                                                                                                                  H   0.4
                                                                            0                                     Matagorda   Bay   (6)                                       (n
                   Matagorda   Bay   (6)
                    Brazos River     (1)                                                                           Brazos River     (1)
                   Galveston Bay     (6)                                                                          Galveston Bay     (6)
                                                                                                                      Sabine  Lake  (1)
                       Sabine  Lake  (1)                                       td                                                   (1)                                    0%% (7-4
                                                                                                                  Calcacieu   Lake  2)                                        1-3
                    Calcacieu  Lake  (2)
                                                                                                          Joseph Harbor Bayou       (1)
           Joseph Harbor Bayou       (1)
                   Vermillon Bay     (1)                                      0                                   Vermillon Bay     (1)
                 Atchafalaya Bay     (1)                                                                        Atchafalaya   Bay   (1)
                      Caillou Lake   (1)                                                                          . Caillou   Lake 1)
                   Terrebone Bay     (2)                                                                         Terrebone Bay      (2)
                   Barataria Bay     (3)                                                                          Barataria Bay     (3).
                Mississippi River    (2)                                                                      Mississippi River     (2)
                    Breton Sound     (2)                                                                           Breton Sound     (2)
                      Lake Borgne    (2)                                                                            Lake Borgne     (2)
               Mississippi Sound     (3)                                                                      Mississippi Sound     (3)
                        Mobile Bay   (2)                                                                              Mobile  Bay   (2)
                    Pensacola  Bay   (2)                                                                           Pensacola  Bay 2)
                                                                                                            Choctawhatchee    Bay   (2)                                        0
             Choctawhatchee    Bay   (2)                                                                             Panama   City  (1)
                      Panama   City  (1)
                 San Andrew    Bay   (1)                                                                       San Andrew     Bay   (1)
                 Apalachicola  Bay   (2)                                                                        Apalachicola  Bay   (2)
                                                                                                                 Suwanee River      (1)
                  Suwanee River      (1)                                         0
                        Cedar Key    (1)                                         0                                    Cedar Key     (1)
                       Tampa Bay     (5)                                                                              Tampa   Bay   (5)
                Charlotte Harbor     (2)                                                                       Charlotte Harbor     (2)
                       Naples Bay    (1 )                                                                            Naples Bay     (1)
                     Rookery Bay     (1)                                                                           Rookery Bay      (1)
                                                                                                                      Everglades
                        Everglades   (1)



                                             332                                                                                           333










                                                     C@        C>
                                           0         C)        0

                       Laguna Madre    (2)
                      Corpus Christi   (3)
                        Aransas   Say  (2)
                         Copano Bay (1)
                       Mesquite Bay (1)                                          0
                                                                                 t4
                    San Antonio   Bay  (2)
                 Espiritu Santo   Bay.(2)
                                       .(2)
                      Matagorda   Say  (6)
                       Brazos River    (1)                                   Q%%
                      Galveston Bay    (6)
                          Sabine  Lake (1)                                       tZ
                      Calcacieu   Lake (2)                                       C.4
              Joseph Harbor Bayou      (1)
                                                                                 0
                      Vermillon Bay    (1)
                    Atchafalaya   Bay  (1)
                         Caillou  Lake (1)
                     Terrebone Bay
                       Barataria  Bay  (3)
                   Mississippi River   (2)
                       Breton Sound    (2)
                        Lake Borgne    (2)
                  Mississippi Sound    (3)
                           Mobile Bay  (2)
                       Pensacola  Bay  (2)
                Choctawhatchee    Bay  (2)
                         Panama   City (1)
                    San Andrew    Bay  (1)
                    Apalachicola  Bay  (2)
                     Suwanee River     (1)                                         W
                          Cedar Key    (1)
                         Tampa Bay     (5)
                   Charlotte. Harbor   (2)
                         Naples Bay    (1)
                       Rookery Bay     (1)
                           Everglades  (1)




                                              334


















                          Reprint 3

           Trace Organic Contamination in Galveston
         Bay Oysters: Results from the NOAA National
           Status and Trends Mussel Watch Program


          Terry L. Wade,, Thomas J. Jackson, James M.
           Brooks, Jos6 L. Sericano, Bernardo Garcia-
                 Romero and Dan L. Wilkinson




















                              1-31









_____________________________________________________________________________________________________________________________


								PROCEEDINGS

						The Second State of the Bay Symposium
						 	   February 4-6, 1993
_____________________________________________________________________________________________________________________________










								EDITORS

							Richard W.  Jensen
						Texas Water Resources Institute,
							Texas A&M University

							Russell W.  Kiesling
				          	Galveston Bay National Estuary Program
				  
                                                  and

							Frank S. Shipley
						Galveston Bay National Estuary Program

					    The Galveston Bay National Estuary Program
						`
							Publication GBNEP-23
							   February, 1993





								1-33







                    Trace Organic Contamination in Galveston Bay
                   Oysters: Results from the NOAA National Status
                              and Trends Mussel Watch Program

                    Terry L. Wade, Thomas J. Jackson, James M. Brooks, Josi L. Scricano, Bernardo
                                         Garcia-Romero and Dan L. Wilkinson
                    Geochemical and Environmental Rcsearcli Group, College of Geosciences and
                                       Maritime Studies, Texas A&M University


                 It is important to determine the current status of contaminant concentrations in
                 order to assess the environmental response to management decisions that reduce or
                 stop the input of selected contaminants. To fill this information gap with high
                 quality data for U   -S. coastal areas, the National Oceanic and Atmospheric
                 Administration (NOAA) established the National Status and Trends (NS&T) Mussel
                 Watch Program. As part of the NS&T Program, sediment and oyster samples have
                 been collected and analyzed from over 70 estuarine sites in the Gulf of Mexico
                 representing all major Gulf Coast estuaries. Sampling sites were located in areas not
                 influenced by known point sources of contaminant inputs, including Galveston Bay.
                 Oysters were employed as sentinel organisms because they are cosmopolitan,
                 sedentary, bioaccumulate, able to provide an assessment of bioavailability, not
                 readily capable of metabolizing contaminants, able to sukvive pollution loading,
                 transplantable, and commercially valuable.        Oysters are, therefore, excellent
                 biomonitors for contamination in estuarine areas.

                 The Galveston Bay system is one of the largest and most economically important
                 estuaries along the U.S. Gulf Coast. This area has been the recipient of various
                 contaminant inputs because of an aggressively growing urban and industrial region.
                 Houston, Deer Park, Baytown, Texas City and Galveston, surrounding Galveston Bay
                 to the nort@h''I-and-west, are some of the most heavily industrialized areas in Texas.
                 Hundreds of ind'ustrial plants, including petrochemical complexes and refineries,
                 bordering the Galveston Bay estuarine system, as well as runoff, are likely to
                 introduce significant amounts of organic contaminants into the Bay. In general,
                 ecological studi6s have suggested that the waters of Galveston Bay contained
                 contaminants in sublethal amounts which caused stress to organisms resulting in
                 significant changes in the estuarine community structure. Galveston Bay NOAA
                 NS&T sampling sites (Figure 1) included the Ship Channel (GBSC), Yacht Club
                 (GBYC), Todd's Dump (GBTD), Hanna Reef (GBHR), Offats Bayou (GBOB) and
                 Confederate Reef (GBCR). Samples were collected in the winter starting in January
                 of 1986 at four sites (GBYC, GBTD, GBHR, GBCR) and in December of 1987 (Year 3) at
                 two additional sites (dBSC, GBOB). Samples were collected at some of these sites at
                 other times to provide information on seasonal trends in contaminant
                 concentrations. Sediments (top 1 cm) and oysters (20) were collected at three stations
                 at each site and analyzed for polynuclear aromatic hydrocarbons (PAH),
                 polychlorinated biphenyls (PCB), chlorinated pesticides (e.g., DDT, chlordane), and


                                                          1-34






                                                                                                                                 W
                                                                                                                                           W.
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                                                                                                         5






                                                                                   CL CAR
                                                            -A                     LAKJ-                                                                                         5AY              7.
                                                                   C
                                                                                                   DICKINSON                                                                17
                                                                                                       SAr
                                                                                                                              GALVESTON BAY                                                    ROLLOVCOC? POSSJ
                                                                                     SAW)
                                                                         OICKIN  5_00
                                                                                                          ire
                                                                                               0   5 A    DOLLAR BA)

                                                                                                          TEXAS CITY







                                                                                                      VAY-
                                                           c_       @re                                                               GALVEST N

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                                CHRIS rmAS BAY

                                                                  Figure 1. Galveston Bay sampling sites included the Ship Channel (59), Yacht
                                                                  Club (15), Todd's Dump (16), Offat's Bayou (58), and Confederate Reef (18).


                                                                                                              1-35








              tributyltin. Sampling started in the winter of 1985/86 and is continuing with
              sampling each winter. Seven years of data are currently available and Year 8
              sampling has just been completed. All sample analyses were performed using
              standard operating procedures (SOPs) to provide high quality, precise, accurate, and
              reproducible data. Data quality was further assured by yearly participation in
              NOAA/NIST intercalibration exercises. This allows for direct comparison of NS&T
              Gulf Coast data with NS&T data for the East and West coasts.


              Contaminant concentration patterns were similar for most contaminants. The
              upper bay sites (GBSC, GBYC) had higher concentrations than the mid-bay sites
              (GBTD, GBHR) for PAH, DDT, PCB, and butyltins. Sites from the lower bay (GBOB,
              GBCR) had intermediate concentrations. This most likely results from proximity to
              large urban areas and runoff inputs. The lower contaminant loading in the mid-bay
              region probably results from dilution effects. For example, total PAH average
              concentrations ranged from 20 to 15,000 ng/g. The higher concentrations were
              measured in oysters from the upper portion of Galveston Bay (i.e., GBSC and GBYQ
              and near the city of Galveston (i.e., GBCR and GBOB). Oyster s7ampleg from areas
              farther away from urban centers (i.e., GBHR and GBTD) had average concentrations
              one to two orders of magnitude lower. In general, these concentrations are in good
              agreement with those previously encountered during temporal studies in Galveston
              Bay. Two PAHs, pyrene and fluoranthene, generally accounted for >25% of the total
              PAHs measured. The predominance of these compounds suggests that the maj
                                                                                                Jor
              source of PAHs is from combustion products.

              Average total PCB and DDT concentrations in Galveston Bay oysters were in the 48-
              1100 and 12-240 ng/g ranges, respectively. Most of the DDT residue is present as
              metabolites, DDE and DDD. In general, less than 10% of the total contaminant load
              in oysters is the parent compound, DDT. Samples from the GBYC and GBSC were
              the most contaminated while oysters from GBHR had the lowest residue
              concentrations. ---These concentrations agree with the ranges reported earlier for
              Galveston Bay bivalves. The median concentrations found in Galveston Bay for
              PAH, chlordane, dieldrin, PCB, and butyltins are higher than the median
              concentrations found throughout the Gulf of Mexico for the NS&T Program. The
              median DDT concentrations found in Galveston Bay are about the same as those
              found for the entire Gulf of Mexico. Therefore, compared to the rest of the Gulf of
              Mexico the median concentrations of most organic contaminants are generally
              higher in Galveston Bay. However, when Galveston Bay sites are compared to all
              U.S. NS&T sites none of the concentrations, with the exception of chlordanes at
              GBYC and GBSC, are ranked as high on a national scale.

              Sample collections at other times of the year indicate some seasonal variability of
              contamination concentrations. This may result from the loss of a considerable
              amount of contaminants by oysters during spawning. Other studies of Galveston
              Bay oysters indicate that body burdens of contaminants can change due to
              accumulation and depuration. These preliminary studies indicate. that more
              information regarding the use   of oysters as bioindicators would provide for better
              interpretation of the data from the NS&T program.



 I
 I
 I
 I
 I
 I
 I
 I                         Reprint 4
 1            Indicators of Trace Metal Pollution In
 I                       Galveston Bay
 I            Bobby J. Presley and Kuo-Tung Jiann
 I
 I
 I
 I
 I
 I
 I

                              1-37
 I







                                 Proceedings
                          The Second State of the Bay Symposium
                                     February 4-6, 1993








                                             Editors


                                        Ricard W. Jensen
                                  Texas Water Resotirces Instiftite,
                                      Texas A&M  University

                                       Russell W. Kiesling
                              Galveston Bay National Estuanj Prograrn

                                              and

                                        Frank S. Shipley
                              Galveston Bay National Eshiary Prograrn


                         The Galveston Bay National Estuary Program

                                     Publication GBNEP-23
                                         February,1993



                                                1-39






                     Indicators of Trace Metal Pollution in Galveston Bay

                                             Bobby Joe Presley and Kuo-Tting liann
                                     Department, of Occanograpljy, Texas A&M University


                  Sediments and organisms are usually more reliable and more convenient media for
                  trace metal analysis than is water. Even polluted bay and estuarine water is very low in
                  trace metal concentration, making it difficult to analyze reliably. Furthermore,
                  concentrations in water are subject to rapid changes with changing metal inputs.
                  Sediments and organisms have higher metal concentrations and they integrate values
                  over time so less frequent sampling is needed.

                  Oyster (Crassostrea virginica) and other bivalves have been used as "sentinel" organisms
                  for assessing the pollution status of marine water bodies for almost twenty years. For
                  example, Goldberg et al (1983) report data for a USEPA funded "Mussel Watch"
                  program conducted in 1976-78, and the current NOAA-funded "National Status and
                  Trends Program" (NS&T) is an outgrowth and extension of the "Mussel Watch"
                  concept. Bivalves are widely recognized as being responsive to changes in pollution
                  levels in the environment, good accum, ulators of pollutants, widely distributed along
                  coasts, and easy to collect and analyze. Sediments also respond to changes in pollutant
                  trace metal inputs because most pollutant metals are particle reactive; that is, they
                  readily attach to particles which can then sink to the bottom and become part of the
                  sediments.


                  Oysters have been collected at six different sites in Galveston Bay (GB) since 1986 as
                  part of NS&T. Each site is on an identifiable oyster reef and, for the first 5 years, twenty
                  oysters were taken from each of three stations, the stations being 100 and 500 m apart.
                  Currently only one station is sampled at each site. Each site has been sampled once
                  each year, except two of the sites were not sampled the first two years. The twenty
                  oysters from each station are combined and analyzed as a single sample ea*.h year. In
                  most cases, stations are located hundreds of meters to many kilometers away from any
                  obvious point sources of pollutant inputs in an attempt to characterize large areas of
                  GB, rather than to identify specific point sources of pollutant input. Similar NS&T
                  sampling is conducted in all other major bays and estuaries along the U.S. Gulf of
                  Mexico coastline. The program allows different bays to be compared and pollutant
                  concentration changes with time at a given bay to be documented.

                  Data obtained by atomic adsorption spectrophotometry (AAS) after acid digestion of
                  oysters from the first four years of NS&T have been reported (Presley et al., 1990, 1991).
                  The samples were an   'alyzed for Ag, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Si, Sn, and
                  Zn. Flame AAS was used for Cu, Fe, and Zn, which exhibit high concentrations in
                  oysters, cold vapor AAS for mercury, and graphite furnace AAS for the remaining
                  elements. Blanks and reference materials were analyzed with the samples. Precision
                  and accuracy of the data was estimated to be ï¿½10%.



                                                              1-40








                      Trace metal concentrations found in oysters collected along the entire       Gulf of Mexico
                      coastline during the first four years of NS&T were generally similar to those reported in
                      oysters taken from non-contaminated water in other parts of the world (Presley et al.,
                      1990). Only a few sites showed obvious trace metal pollution and these were restricted
                      geograph.ically such that nearby sites were usually unaffected. Abnormally high or low
                      values at a site did, however, usually repeat year after year suggesting local control.
                      Abnormal sites for most metals were just as likely to be visibly pristine as to be highly
                      industrialized.


                      Presley et al. (1991) reported that the oysters collected in Galveston Bay during the first
                      four years of NS&T were similar in trace metal content to those collected elsewhere
                      along the Gulf coastline, i.e., there was no indication of generalized trace metal
                      pollution in GB. The average Ag, Cd, Cr, Fe, Mn, and Pb in GB oysters differed by 10%
                      or less from the Gulf-wide average. Copper was 13% higher in GB, while Ni was 15%
                      higher, and Se 16% higher. Zinc, however, was 43% higher. Furthermore, the highest
                      Zn levels were found along the industrialized west side of Galveston Bay.

                      The four year NS&T sampling and analysis of oysters from the Gulf Coast discussed by
                      Presley et al. (1990, 1991) has been-'continued for three more years with at least an
                      additional three years planned. The basic patterns in concentration variability seen
                      earlier have not changed significantly. With few exceptions, Galveston Bay oysters
                      continue to be about average in trace metal content when compared to oysters from
                      other bays along the Gulf Coast. Furthermore, oysters from near the entrance to the
                      indand part of the Houston Ship Channel and from the industrialized western shoreline
                      have about the same metal content as those from pristine areas of East and West Bays.

                      In non-funded student research designed to further investigat    e the relationship between
                      trace metal concentrations in oysters and proximity of industry, samples were taken at
                      twelve sites at the end of June and at the end of September, 1992. At most sites, 10-30
                      individual oysters were taken. They were collected, handled, and analyzed as
                      described previously (Presley et al., 1990). No oysters were collected in extreme
                      northern Galveston Bay, but shoreline samples were taken near Eagle Point and the
                      highly industrialized areas of Texas City. Samples were also taken in central GB along
                      the open-water part of the Houston Ship Channel and from East and West Bays.

                      Most trace metal concentrations were lower in oysters collected in September, 1992,
                      than those collected at the same locations in June, 1992. In many cases, the decrease was
                      by a factor of two and was, thus, larger than most site to site differences ill the bay' It is
                      very unlikely that this change was caused by human activity because there is little
                      correlation betwe.en metal concentrations in oysters and proximity to population or
                      industry, and even Fe concentrations in the oysters changed by up to a factor of two.
                      Rather, the change in trace metal concentration must be related to some physiological
                      change in the oysters. In order to minimize such changes, oysters are always collected
                      in December for NS&T. The September, 1992, data is similar to the six-year average
                      NS&T data, so perhaps oysters change in metal content less during fall and winter.


                                                             1-41








              Silver concentrations are above the Gulf-wide average in several GB samples, but with
              no clear relationship to proximity to industry. Very high Ag concentrations were found
              in oysters collected at Confederate Reef in years V and VI (1990-1991) of NS&T, but not
              in previous years. A site on Deer Island near Confederate Reef was sampled for the
              1992 student work. Oysters from it were somewhat higher than average in Ag content,
              but no more so than those from other sites in Galveston Bay. It is possible that human
              activity is responsible for the silver and zinc enrichments but no specific causative
              activity can be identified. In any case, the enrichments are not high enough to harm the
              oysters or human health.

              Based on the discussion above and other data from our laboratory, oysters seem to
              integrate trace metal concentrations in the surrounding environment for one to two
              months. For a longer integration period sediments can be analyzed. As part of the
              unpublished student work reported here, sediments were collected at nineteen locations
              throughout Galveston Bay, including Morgan's Point and other locations along the
              industrialized northern and western shoreline, as well as locations far back into East
              Bay well away from industry. The sediment was sieved to separate the <63 Prn grain
              size fraction, which was analyzed along with an aliquot of the unsieved bulk sample.
              Analysis was by AAS after both a partial leach of the sample with 0.5 N HC1 and
              complete dissolution using HN03-HCI-HF. Results showed the sediment to be
              generally constant in trace metal concentration from place to place when the <63 @m
              size fractions were compared and to be similar to sediment from other Texas bays
              which were analyzed for NS&T. Average concentrations of metals in the <63 pm
              fraction of Galveston Bay sediments and the percentage ofthat metal leachable with 0.5
              N HCI are shown in Table 1, along with average values for other Texas bays
              (normalized to 100% <63 pm grain size). Data from Morse et al. (in press) on another
              set of sediment samples taken from throughout GB confirms the relative constancy of
              trace metal concentrations. The most notable exception to sediment trace metal
              constancy found in the present work was a sample taken near the end of the Texas City
              Dike. It had <0.5% fine material but that fine material was enriched in several metals.
              Based on other data from this laboratory, it may well be that the fine fraction of very
              sandy sediment is easily enriched in trace metals from human activity.


              Table 1.   Average cdncentratioiis of trace inetals hi the <63 joit sizefraction of
                         Galveston Bay and other Texas bay sedhnents.

                                  Fe       Ag        As      Cd        CU       Ni       Pb       Zn
                                          (PPM)   (PPM)     (PPM)    (PPM)    (PPM)    (PPM)    (PPM)
              GB      Avg         2.9     0.164    8.21     0,157     28.7     23.9      24.5     98.8
              GB      S.D.        0.7     0.040    1.57     0.106      15.5     4.4      4.6      22.7
              GB   Leach (%)      15       61        19      76        56       21       68       33
              TX      Avg.        2.12    0.156    7.91     0.253      15.1    17.7      24.5     85.3
              TX      S.D.        0.83    0.055    3.27     (1171      3.5      4.2      6.0      25.2







                                                             1-42







                Several species of finfish (flounder, drum, trout, catfish, etc.) as well as blue crabs and
                oysters were collected from Galveston Bay in May-September, 1990, for the Galveston
                Bay National Estuary Program (GBNEP) (Brooks, 1992). These were analyzed for trace
                metals in our laboratory following procedures used for NS&T (Presley et al., 1990). The
                samples came from near Morgan's point, Eagle point, Hannah Reef and Carancahua
                Reef; thus, from areas of contrasting proximity to population centers and industry. In
                spite of the contrasts between the collection sties, no clear differences were found in
                trace metal concentrations in the organisms. Furthermore, the GB organisms were
                similar in trace metal content to organisms from non-polluted bays elsewhere.

                Oysters are better accumulators of trace metals and, being attached to the sediment,
                should better characterize a site than the other organisms collected for GBNEP. The
                GBNEP oysters were generally similar in trace metal content to NS&T oysters from GB,
                but somewhat lower in Zn concentration. Zinc was also less clearly related to
                population and industry than in NS&T.

                GB fish flesh was much lower in trace metals than oyster flesh and while isolated high
                values were found, concentrations were generally similar to those found -in non-
                contaminated bays elsewhere. Trace metals in fish showed no relationship to
                population or industry. Fish livers proved to have much higher concentrations of trace
                metals (except for Hg) than fish flesh and high variability, but again no clear
                relationship to population or industry. Blue crabs from GB were generally intermediate
                in trace metal concentration between fish flesh and oyster flesh with similar high
                variability and lack of correlation with population or industry. The GBNEP data,
                therefore, gave no indication of trace metal pollution in Galveston Bay.


                                                       Bibliography

                Brooks, J.M. 1992. Toxic contaminant characterization of aquatic organisms in
                       Galveston Bay: a pilot study. The Galveston Bay National Estuary Program
                       GBNEP-20.

                Goldberg, E. D., M. Koide, V. Hodge, A.R. Flegal and J. Martin. 1983. U.S. mussel
                       watch: 1977-1978 results on trace metals and radionuclides. Estuarine, Coastal
                       and Shelf Science, 16: 69-93.

                Morse, J.W., B.J. Presley, R.J. Taylor, G. Benoit and P. Santschi. (in press). Trace metal
                       chemistry of Galveston Bay: water, sediments and biota.

                Presley, B.J., R.J. Taylor and P.N. Boothe. 1990. Trace Metals in Gulf of Mexico oysters.
                       The Science of the Total Environment, 97/98, 581-593.







                                                           1-43





           Presley, B.J., R.J. Talyor and P.N. Boothe. 1991. Trace Metals in Galveston Bay oysters.
                In, Proceedings, Galveston Bay characterization workshop, Feb. 21-23, 1991. The
                Galveston Bay National Estuary Program Publication GBNEP-6, F.S. SI-lipley and
                R.W. Kiesling (eds.).

          Texas A&M Geochemical and Environmental Research Group. 1990. NOAA status and
                trends mussel watch program for the Gulf of Mexico. Technical Report
                submitted to National Oceanic and Atmospheric Administration, Rockville, MD.
















































                                                   1-44


















                          Reprint 5

                 Oysters as Biomonitors of the
                     APEX Barge Oil Spill


         Terry L. Wade, Thomas J. Jackson, Thomas J.
                 McDonald, Dan L. Wilkinson,
                     and James M. Brooks





















                              1-45









                 Proceedi-n- -as


                                                            1993
                             International Oil Spill
                                                 Conference
                               (Prevention, Preparedness, Response)






                                                   March 29-April 1, 1993
                                                         Tampa, Florida



                                     *onsored by: United States Coast Guard, American Petroleum Institute,
                                                  and U.S. Environmental Protection Agency




                                                 USCG API                       EPA




                                                OIL POLLUTION CONTROL A COOPERATIVE EFFORT






                                                                  1-47










                                                                             OYSTERS AS BIOMONITORS
                                                                        OF THE APEX BARGE OIL SPILL


                                                                    Terry L. Wade, Thomas J. Jackson, Thomas j. McDonald,
                                                                                   Dan L. Wilkinson, James M. Brooks
                                                                                              Texas A&M University
                                                                           Geochemical and Environmental Research Group
                                                                                                 833 Graham Road
                                                                                          College Station,         Texas 77845



                           ABSTRACT: The collision of the Greek tankership Shinoussa resulted                      Apex barge oil spill indicated that they efficiently metabolize the PAH
                           in a spill of an estimated 692,000 gallons of cxalyticfeed stock oil into               after the initial insult.` This report discusses the use of oysters as
                           Galveston Bay on July 28, 1990. Oysters were collectedfrom Galveston                    biomonitors of the Apex barge oil spill at the historical NS&T Todds
                           Bay Todds Dump (GBTD) 235 daysprevious to the spill and 6,3 7,132,                      Dump site and at Redfish Island, a site reported to be impacted by the
                           and 495 days after the spill. Oysters were also collectedfrom Galveston                 od Spill.3
                           BayRedfish lslandfGBRI), asiteknown to be impacted by the spill, 37
                           and 110 days after the spill. The concentration of the 24 polynuclear
                           aromatic hydrocarbons (PAH) measuredfor the National Oceanic and                        Materials and methods
                           Atmospheric Administration's national status and trends program
                           (NS& T) site showed a sharp increasefirom about 100 nglg to over 600
                           nglg one week after the spill compared to concentrations 235 days                         Oysters (Crassostrea virginica) were collected for analyses from
                           previous to the spill. The concentration of the 24 NS& T PAH in oysters                 Galveston Bay Todds Dump and Redfish Wand. Individual stations at
                           from GBRI ranges from 400 to over 1000 ng1g. Soon after the spill the                   each site are generally from 100 to 1,000 m apart. An analysis at each
                           concentration of the 24 NS& T PAH at Todds Dump decreased to levels                     GBTD, from routine NS&T sampling program, represents a compos-
                           not statistically different from pre-spill samples. However, analyses of                ite of 20 individual oysters, However, samples from GBTD and GBRI
                           alkylated and sulfur containing aromatic compounds indicate the oys-                    taken 6, 37, and 110 days after the spill represent from I to 20 oysters
                           ters were stillcontaminafed with Apex barge odw kast37 and 110 days                     depending on availability.
                           after the spill at GBTD and GBRI, respectively. Data from NS&T                            Tissue extraction followed the method used for NS&V Approx-
                           sampling at GBTD more than a year after the spill (495 days) indicates                  imately 15 grams of wet tissue were used for the PA14 analysis. After
                           thepresence of alkylated aromatic hydrocarbons that may befirom Apex                    the addition of internal standards (surrogates) and 50 grams of an-
                           barge oil still in the area. It appears that a sink of Aper barge oil (i.e., in         hydrous Na2SO,, the tissue is extracted three times with dichlo-
                           sediments) may periodically be released by storms or other events into                  romethane using a tissuernizer. The solvent is concentrated to approx-
                           the ecosystem near GBTD. Therefore, bioavailable Apex barge oil is                      imately 20 mL in a flat-bottomed flask equipped with a three-ball
                           still present and may adversely affect oysters 495 days after the spill.                Snyder column condenser. The tissue extract is then transferred to
                                                                                                                   Kudema-Danish tubes heated in a water bath (6(r C) to concentrate
                                                                                                                   the extracts to a final volume of 2 mL. During concentration, the
                                                                                                                   solvent dichloromethane is exchanged for hexane.
                              Oysters are analyzed as part of NOAA's national status and trends                      The tissue extracts are fractionated by alumina:sil@ (80 to 100
                           (NS&T) program' to detemiine the current status and long-term                           mesh) open-column chromatography. Ile silica gel is activated at 170*
                           trends of selected contaminant loadings. As part of this program,                       C for 12 hours and partially deactivated with 3 percent distWed water
                           pollynticlear aromatic hydrocarbons (PAH), toxic components of oils,                    (v/w). Twenty grams of silica gel are slurry packed in dichloromethane
                           are measured. Coastal waters are continually impacted by chronic                        over 10 grams of alurnina. Alumina is activated at 400* C for four hours
                           inputs of PAH from wastewater treatment plants, storm water runoff,                     and partially deactivated with I percent distilled water (v/w). The
                           atmospheric deposition, and the like. The NS&T program is designed                      dichloromethane is replaced with pentane by clution. The extract is
                           to determine the extent of this chronic contamination throughout the                    then applied to the top of the column. The extract is sequentially eluted
                           entire U.S. coastal area including the Gulf Coast. However, sporadic                    frowhe column with 50 mL of pentane (alipiatic fraction) and 200 mL
                           inputs of PAH into the coastal environment also come from small- and                    of 1:1 pentane:dichloromethane (aromatic fraction). The aromatic
                           large-scale oil spills.' The seven years of historical NS&T data along                  fraction is further purified by high-pcrformance liquid chromatogra-
                           with more recent U. S. EPA environmental monitoring and assess-                         phy to remove lipids. The lipids are removed by size exclusion using
                           ment-near coastal (EMAP-NC) data can be used as the basis for a                         dichloromethane as an isocratic mobde phase (7 mLJmin) and two 22.5
                           geochemical and environmental response strategy (GEARS) as de-                          X 250 mm Phenogel 100 columns.' The purified aromatic fraction is
                           smibed by Brooks et aL' This approach utilizes available data to                        collected from 1.5 minutes prior to the clution of 4,4'-dibromo-
                           provide historical control sites to determine the extent of a spill and                 octal3uorobiphenyt to 2 minutes after the clution of perylene. Tle
                           allow for a better estimate of ecosystem exposure.                                      retention times of the two marker peaks are chocked prior to the
                              On July 28,1990, an estimated 692,000 gallons of catalytic feed stock                beginning and at the end of a set of ten samples. The purified aromatic
                           oil product was spilled into Galveston Bay when a tanker collided with                  fraction is concentrated to I mL using Kudema-Danish tubes heated in
                           three Apex barges in the Houston Ship Channel. The spill was within a                   a water bath at 60* C.
                           mile of Todds Dump (GBTD), one of the historical NS&T oyster                              Quality assurance for each set of 20 samples includes a procedural
                           sampling sites. The spill resulted in the closure of recreational and                   blank, matfix spike, duplicate, and tissue standard reference material
                           commercial fisheries for several days. A study of frsh exposed to the              313  (NIST-SRM 1974), which are carried through the entire analytical

                                                                                                           1-48






314		1993 OIL SPILL CONFERENCE

									scheme.  Internal standards (surrogates)are added to the samples prior
									to extraction and are used for quantitation.  The surrogaters are d6-
									naphthalene, d10-acenaphthene, d10-phenanthrene, d12-chrysene, and
									d12-perylene.  Surrogates are added at a concentration similar to that
									expected for the analytes of interest.  To monitor the recovery of the
									surrogates, chromatography internal standards d10-flourene and d12-
									benzo(a)pyrene are added just prior to GC-MS analysis.
									  Gas chromatography-mass spectrometry (GC-MS).  The PAHs were
									separated and quantified by GC_MS (HP5890-GC interfaced to a
									HP5970-MSD).  The samples were injected in the splitless mode onto a
									0.25 mm x 30 m (0.32 pm film thickness) DB-5 fused silica capillary
									column (J & W Scientific, Inc.) at an initial temperature of 60 c and
									temperature programmed at 12 C/min to 300 C and held at the final
									temperature for 6 minutes.  The mass spectral data were acquired using
									selected ions for each of the PAH analytes.  The GC-MS was calibrated
									and linearity determined by injection of a multicomponent standard at
									five concentrations ranging from 0.91 ng/uL to 1 ng/uL.  Sample com-
									ponent concentrations were calculated from the average response
									factor for each analyte.  Analyte indentifications were based on correct
									retention time of the quantitation ion (molecular ion) for the specific
									analyte and confirmed by the ratio of quantitation to confirmation ion.
									  Calibration check samples are run with each set of samples (begin-
									ning, middle, and end), with no more than 6 hours between calibration
									checks.  The calibration check must maintain an average response
									factor within + or - 10 percent for all analytes, with no one analyte greater
									than + or - 25 percent of the known concentration.  A laboratory reference
									oil solution is also analyzed with each set of samples to confirm GC-MS
									system performance and peak indentification.


									Results and discussion

										
									  The location of the Apex barge oil spill is shown in Figure 1.  A
									detailed account of the spill, including cleanup and bioremediation
									activities has been published. 3  the spilled oil was described as a
1.  Location of Galveston Bay Todds Dump (GBTD)		catalytic feed stock or similar to a No. 5 fuel oil 8 with a density of 0.92
and Galveston Bay Redfish Island (GBRI) collection	g/mL.  The Apex barge oil is not a typical Gulf Coast oil, but resembles
sites and the Apex barge oil spill				a distillate or refined product.  This is apparent from the gas chromato-









		0.00		8.12		16.25		24.37		32.50		40.63		48.75		56.86		65
RT in minutes

	Figure 2.  Gas chromatogram of Apex barge oil spilled into Galveston Bay (normal alkanes with 21, 27, and 35)




                                                             1-49

  







                                                                                                                                             FATE AND EFFECTS                    315


                                                                       Table 1. Oyster NS&T PAH, total PAH, and C3-phenanthrene
                                                                          concentrations before and after the Apex barge oil spill


                                                                                 Davs before                                                               C3'
                                                             Collection                 or after        NS&T PAH              Total PAH             phenanthrenes
                                             Site               date                    spill               (ngig)               (ng1g)                    (ng/g)
                                         GBTD3                  12/6189                 -235                  141                  1,057                     10
                                         GBTD 2                 12/6189                 -235                  175                   471                      10
                                         GBT*D 1                12/6/89                 -235                  323                  1,893                     10
                                         Apex Spill             7/28190                    0                  -1                   -1                      -1
                                         GBTD                   8/3/90                     6                  705                14,411                    2,293
                                         GBTD                   9/3/90                    37                  122                   852                      77
                                         GBTD I                 12n/90                  132                   120                   877                    122
                                         GBTD 2                 12nlgo                  132                   150                  1,204                   178
                                         GBTD 3                 12nlgo                  132                   364                  4,313                   781
                                         GBTD                   12/5191                 495                   236                  1,997                   213
                                         GBRI 1                 9/3/90                    37                  790                19,146                    2,735
                                         GBRI 2                 9/3/90                    37                  470                12,723                    1,636
                                         GBRI                  11/15/90                 110                 1,110                25,213                    3,238
                                         1. Not applicable


                          graph (GQ shown in Figure 2.Tbe GC is a plot of detector response                       variability within a site for oyster samples collected on the same
                          versus increasing temperature and time. The area of peaks and their               date makes evaluation of input from the Apex barge spill more prob-
                          retention times are used to determine the identity and concentration of           lematic. However, the total PAH in these samples were predominantly
                          the components. The labeled peaks in Figure 2 are normal alkanes with             lower molecular weight alkylated naphthalenes, alkylated fluorene
                          21, 27, and 35 carbon, respectively. Other peaks represent normal                 and Cj- and C2-phenanthrenes. No C3-phenanthrenes were detected
                          alkanes ranging from 15 to 37 carbons. The presence of oaly these                 (Table 1). Based on the fact that the Apex barge oil that was spilled
                          higher boiling components is consistent with a distillate or refined              contained predominantly higher molecular weight hydrocarbons
                          product and is not typical of a Gulf Coast oil.                                   (Figure 2), it is not surprising that C3-phenanthrenes might be better
                            The total oyster concentration of the 24 PAH measured as part of                indicators of oyster exposure to the Apex barge oil than NS&T PAH or
                          NOAA NS&T program, the total of all PAH measured, and the                         total PAH. Therefore, the concentration Of C3-phenanthrenc was plot-
                          concentration of aU the phenanthrenes containing 3 carbon (C,-phen-               ted versus the days before or after the spill (Figure 4). This log plot
                          anthrene) are provided in Table 1. Some of these data are also pres-              indicates a clear distinction between oysters collected before the spill
                          ented graphicaUy in Figures 3 and 4. The total NS&T PA14 ranged                   and those collected after the spill. AD samples collected after the spill
                          from 120 to 1110 ng1g. The concentrations found at GBTD 235 days                  had detectable concentrations of C,-phenanthrenes, while none of the
                          before the spill ranged from 141 to 323. This GBTD data shows an                  samples collected before the spill do.
                          increase in concentrations as you move from the western onshore                     'Me data for all the PAH individual compounds or groups of com-
                          station (GBTD-3) to the Offshore station (GBTD-1). The 24 NS&T                    pounds that are present in the Apex barge oil as well as oysters
                          PAH were only diagnostic of the spill at higher concentrations (i.e.,             collected from GBTD 235 days before and 132 days after the spill are
                          greater than 400 ng/g). Total PAH concentrations in oysters from                  shown in Figure 5, 6, and 7, respectively. A description of the compo-
                          GBID and GBRI ranged from 471 to 25,213 ng/g. The total oyster                    nents that were measured and plotted is fisted in Table 2. These plots
                          PAH concentrations when plotted versus the number ofdays before or                provide a "fingerprint" ofthe Apex barge oil and the PAH distribution
                          after the spill that the samples were collected (Figure 3) clearly show           found in the oysters. Clear differences appear in these fingerprints.
                          the influence of the Apex barge spill at concentrations above 10,000 ng/          The GBTD sample from NS&T Year 5 (235 days before the spill)
                          g. Based on total PAH in oysters, the bioavailabibty of Apex barge spill          sampling contains mostly peaks in the left side of the plot (Figure 6)
                          oil is clearly evident for the sample collected at GBTD 6 days after the          indicating a predominance of lower molecular weight PAR The
                          spill and samples at GBRI, located closer to the spill, 37 and 110 days           GBTD NS&T Year 6 (132 days after the spill) samphng has mostly
                          after the spW (Table I and Figure 3). The oyster total PAH concentra-             peaks in the midrange of the plot (Figure 7). The fingerprint from the
                          tion was 852 ng/g at GBTD 37 days after the spill. The total PAH oyster           GBTD oysters after the oil spill is similar to the fingerprint for the
                          concentration 235 days before the spill at the three GBTD sites was               Apex barge oil (Figure 5). This indicates that these oysters are still
                          1057, 471, and 1893, respectively (Table 1). Therefore the concentra-             being exposed to Apex barge oil. The NS&T oyster samples collected
                          tion at GBTD 37 days after the spill is within the range of concentra-            in Year 7 (495 days after the spill) also appear to contain a PAH
                          tions of total PAH found before, the spill (Figure 3).                            fingerprint consistent with bioaccumulation of Apex barge oil.


                          100000                                                                              10000.



                                                                                                              1000,
                        'ElOODO                                                                             z
                                                                    0                                                                                0
                                                                                                                too.-


                                                                                                            z
                            1000.:
                         it.                                                                                W                    I           I         -A
                         0                                                     0 TOTAL GErM                       10                                           C3 PHEN G
                                                                               0 TOTAL GBRI                                                                    UP
                                                                                                            U
                             too--
                                -400          -200         0           200          400          60D              -400         .200         0            200        400           600
                                   DAYS BEFORE H OR AFTER (+) THE APEX SPELL                                         DAYS BEFORE           OR AFTER (+) THE APEX SPILL
                          Figure 3. Total PAK concentrations in oysters before and after the                Figure 4. CI-phenanthrene concentrationsin oysters before and after
                          Apex barge oil spill                                                              the Apex barge oil spill



                                                                                                   1-50






316		1993 OIL SPILL CONFERENCE


	800									Table 2. Polynuclear aromatic hydrocarbons (PAH) analyzed

	700									____________________________________________________________________________

	600									Abbreviation						Analyte
										____________________________________________________________________________
	500									Naph						naphthalene
																C1-naphthalenes
	400															C2-naphthalenes
																C3-naphthalenes
	300															C4-naphthalenes
										Bi						biphenyl
	200															acenaphthylene
																acenaphthene
	100									Fl						fluorene
																C1-fluorenes
	  0															C2-fluorenes
	  Naph	Fl	P		CH	BaP	BPe								C3-fluorenes
		Bi	   DBT     FL        BbF     I		DBT						dibenzothiophene
																C1-dibenzothiophenes
																C2-dibenzothiophenes
				Analytes											C3-dibenzothiophenes
										P						phenanthrene
	Figure 5.  Apex barge oil PAH fingerprint (see								anthracene
	Table 2 for abbreviations)											C1-phenanthrene-anthracenes
																C2-phenanthrene-anthracenes
																C3-phenanthrene-anthracenes
																C4-phenanthrene-anthracenes
	350									Fl						fluoranthene
																pyrene
	300															C1-fluoranthene-pyrenes
																benz (a) anthracene
	250									Ch						chrysene
																C1-chrysenes
	200															C2-chrysenes
																C3-chrysenes
	150															C4-chrysenes
										BbF						benz (b) fluoranthene
	100															benz (k) fluoranthene
																benzo (e) pyrene
	 50									BaP						benzo (a) pyrene
																pyrene
	  0									I						indeno{1,2,3-cd}pyrene
	  Naph	Fl	P	CH		BaP	BPe								dibenz{a,h}anthracene
		 Bi     DBT   Fl      BbF         I 		BPe						benzo{g,h,i}perylene

				Abalytes					1.  Used in Figures 5 through 7

	Figure 6.  Oysters PAH fingerprint 235 days before
	the Apex barge oil spill, NS&T Year 5 (see Table 2
	for abbreviations)
										Conclusions

										  The analyses of oyster samples before and after the Apex barge oil
	900									spill indicate that oyster do act as biomonitors and that the spilled oil is
										bioabailable.  Measurement of total PAH was diagnostic of exposure
	800									for months after the spill; however the complication of other chronic
										sources of input make diagnosis of exposure specific to Apex barge oil
	700									more difficult.  The use of fingerprinting, using all of the available PAH
										data coupled with the historical NS&T data, suggests that Apex barge
	600									oil or a similar oil is still present in the vicinity of the GBTD NS&T
										sampling site.  The Apex barge oil could be trapped in the sediments in
	500									the shallow surrounding areas.  There is then the potential for periodic
										releases during storms or other events that disturb the sediments.  A
	400									more extensive data set might have provided enough information to
										quantitate this possibility better.  However, since the decision was made
	300									to do a Type A assessment of the damage,2 which is based on a natural
										resource damage assessment model for coastal and marine environ-
	200									ments (NRDAM/CME) and not on environmental monitoring, no
										extensive data set exists.  The damage assessment model does not
	100									consider the fact that bioavailable PAH from the Apex barge oil spill
										may still be present 495 days after the spill.  While the use of computer
	  0									models to assess damage is a politically expedient measure, in the case
	  Naph	FL		P	CH		BaP	BPe	of the Apex barge spill there is insufficient date to determine it it
		Bi		DBT	  Fl       BbF        I		adequately considers long-term damae to the enviromnent.  More
				   Analytes					research is needed to address this possible limitation of the model.

	Figure 7.  Oyster PAH fingerprint 132 days after
	the Apex barge oil spill NS&T Year 6 (see Table 2
	for abbreviations)



										1-51
				   						









                                                                                                                                           FATE AND EFFECTS                   317


                       Acknowledgments                                                                   4. Jackson. T. J., T. L. Wade, T. J. McDonald, D. L. Wilkinson, and
                                                                                                            J. M. Brooks, in press. Polynuclear aromatic hydrocarbon contami-
                                                                                                            nants in oysters from the Gulf of Mexico (1996-1990). Environmen-
                         This research was partially funded by the National Oceanic and                     tal Pollution
                       Atmospheric Administration (NOAA), U. S. Department of Com-                       5. Krahn. M. M., L. K. Moore, R. G. BogaT, C. A. Wigren,
                       merce, Grants 50-DGNC-5-00262 and 50-DGNC-0-00047 from the                           Chan. and D. W. Brown, 1988. High- performance liquid chroma-
                       Office of Ocean Resources Conservation and Assessment; U.S. Envi-                    tOgT2phV method for isolating organic contaminants from tissue and
                       ronmcntal Protection Agency, Galveston Bay National Estuaries Pro-                   sediinen't extracts. Journal of Chromatography, v 437, ppl6l-175
                       gram, Contract IAC (90-91) 1145; and the Geochernical and Environ-                6. McDonald, S. J., J. M. Brooks, D. Wilkinson, T. L. Wade, and
                       mental Research Group, Texas A&M University.                                         T. J. @ IcDonald, 1991. 'nc effects of the Apex barge oil spill on the
                                                                                                            fish of Galveston Bay. Proceedings of the Galveston Bay Character-
                                                                                                            ization Workshop, Feb. 21-23, 1991, pp85-86
                                                                                                         7. McDonald, S. J., T. L. Wade, J. M. Brooks, and T. J. McDonald,
                                                                                                            1991. Assessing the exposure of fish to a petroleum spill in Gal-
                       References                                                                           veston Bay, Texas. in Water Pollution: Modelling, Measuring and
                                                                                                            Prediction, L. C. Worbel and C. A. Brebbia, eds. Computational
                       I . Brooks, James M., Michael A. Champ, Terry L. Wade, and Sus-                      Mechanics Publications, Southampton and Elsevier Applied Sci-
                           anne J. McDonald, 1991. GEARS: Response strategy for oil and                     ence, London, pp707-718
                           hazardous spHls. Sea Technology, April 1991, pp25-32                          8. Nelson, C. 1., 1990. NOAA Response Report, October 29, 1990.
                       2.  Galveston Bay Oil Spill Plan, 1992. Draft Assessment Plan for the                Apex T/B Barges 3417 & 3503 Collision and Oil Spill, Houston Ship
                           Measurement of Natural Resource Damages. Available from J. H.                    Channel Buoy 58, Galveston Bay, Texas, 29 July 1990
                           Jeansonne, Damage Assessment Center, Southeast Region, 9450                   9. Wade, T. L., E. L. Atlas, J. M. Brooks, M. C. Kennicutt 11, R. G.
                           Koger Blvd., St. Petersburg, Florida 33702. 17pp                                 Fox, J. Sericano, B. Garcia-Romero, and D. DeFreitas, 1998.
                       3.  Green, T. C., 1991. 'ne Apex barges spill, Galveston Bay, July                   NOAA Gulf of Mexico status and trends program: Trace orgarlic
                           1990. Proceedings of the 1991 Intemational Oil Spill Conference,                 contaminant distribution in sediments and oysters. Estuaries, v 11,
                           American Petroleum Institute, Washington, D.C., pp291-297                        ppl7l-179













































                                                                                                    1-52


















                           Reprint 6

           Field Studies Using the Oyster Crassostrea
          virginica to Determine Mercury accumulation
                     and Depuration Rates


                Sally J. Palmer, Bobby J. Presley,
               Robert J. Taylor, and Eric N. Powell


















                               1-53


	Bull. Environ. Contam. Toxical. (1993) 51:464-470		Environmental
	1993 Springer-Vertag New York Inc.					Contamination
											and Toxicology

	Field Studies Using the Oyster Crassostrea virginica To
	Determine Mercury Accumulation and Depuration Rates

	Sally J. Palmer,1 Bobby J. Presley,1 Robert J. Taylor,2 and Eric N. Powell1

	Department of Oceanography, Texas A&M University, College Station, Texas
	77843, USA and 2On-Site Analytical, Houston, Texas 77082, USA

	Mercury as an environmental hazard, especially with regard to human health,
	has been of concern since the Minamata diaster (Huddle et al. 1975).  From
	1966 to 1970 a chlor-alkali plant in Point Comfort, texas released mercury-
	enriched wastewater (up to 29.9 kgHg/day)into Lavaca Bay (TWQB 1977).
	Since 1970 the Texas Department of Health (TDH) has periodically closed
	and the re-opened portions of Lavaca Bay to the harvesting of crabs and
	finfish based on their levels (<>0.5 ppm Hg wet weight)of mercury.  A
	1988 closure remains in effect as of this writing (Wiles, 1993).  Mercury
	contamination in Lavaca Bay organisms thus continues to be a problem 22
	years after the chlor-alkali plant ceased releasing mercury into the bay.  The
	goal of the following research was to better understand the behavior of
	mercury in Lavaca Bay.

	Oysters have been widely used as indicator species in metal pollution studies
	(Goldberg et al 1983).  Most such programs have focused on the
	concentrations of metals in oysters from different geographic areas.  This
	study, however, investigated the rate and amount of mercury a "clean" oyster
	would accumulate when transplanted to a contaminated estuary and the rate of
	mercury depurations by contaminated oysters placed in a clean environment.
	The oysters were additionally analyzed bor Ba, Cu, Fe, P, and Zn to test for
	the possible involvement of these metals in mercury accumulation and
	depuration.

	MATERIALS AND METHODS
	
	In August 1991, mature Crassostrea virginica were collected from an
	uncontaminated area, Carancahua Reef, in Carancahua Bay, Texas for use in			Figure 1.  Map of Lavaca Bay showing caging sites and oyster collection
	the accumulation study.  The oysters were placed in nylon bags with a mesh			locations for the accumulation and depuration experiments.
	size of 0.5 cm.  Each bag contained about 50 oysters.  The bags were taken
	about 16 km away to Lavaca Bay and a control site, Keller Bay (see Fig.1)			an area of North Lavaca Bay known to be contaminated with Hg.  These
	and placed on plastic grates, which prevented them from sinking into the soft			oysters were placed in a contaminated area of lower Lavaca Bay, as a
	sediment at the 1 m deep sites.  Nine transplanted oysters from each site were		control site, and in uncontaminated Keller Bay (see Fig. 1).  Deployment
	collected on days 0, 7, 14, 21, 36, and 51, placed in plastic bags, and frozen		techniques and collection times were the same as those used in the
	for later analysis.												accumulation study.

	The depuration study, also conducted in August 1991, used C, virginica from			On each sampling date oysters were removed from the experimental bags in
																both the accumulation and depuration experiments and nine individuals
																from the natural population of C virginica at the respective sites were
	Send reprint requests to Sally Jo Palmer at the above address.					collected.

																In the lab, oysters were thawed and opened with a stainless steel knife.  The
																soft tissue was removed with a teflon spatula and plastic forceps, rinsed in


						464																  465
	
	





                   



1500																		3000                              + Lavaca Bay
                                                                                                                                    Keller Bay   

1000																		2500
	

500						+ Lavaca Bay 										1500               
                                      Keller Bay 


  0																		1000
        0		10	20	30	40	50	60	

                           Day											 		 500


																  		   0
																				0	10	20	30	40	50	60
                																			Day

Figure 2.  Mercury concentrations in Carancahua Reef										Figure 3.  Mercury concentrations in oysters collected
oysters transplanted to Lavaca and Keller Bays for the 51-d									from North Lavaca Bay when transplanted to lower
accumulation experiment.														Lavaca and Keller Bays for the 51 day depuration experiment.


Table 1.  Certified and experimental data for Natural Bureau of Standards						Statistical analyses using SAS Institute, Inc. software (SAS INSTITUTE
reference material 1566a Oyster Tissue and the elemental detection limits						INC> 1985) were performed on the data from the three oyster groups,
obtained in this study.															accumulation (aa), depuration (DD), and the natural population (NP) to
																		investigate possible relationships among the variables analyzed.  The
Element	Hg		Ba		Cu		Zn		P		Fe						Spearmen correlation test and the general linear model (GLM) were used to
		(ppb)		(ppm)		(ppm)		(ppm)		(ppm)		(ppm)						find correlations and linear relationships among variables.  The dry weight of
																		the oysters was used as a covariant in the GLM.  The Least Square Means
NBS Certified																test, LSMEANS, was used to verify changes in Hg with time during the
1566a Oyster Tissue															caging experiments.
 		64.2+	-	NC		66.3+ -	830+ -	6230+ -	539+ -
		6.7				4.3		57		180		15						RESULT AND DISCUSSION
Experimental	
1566a Oyster Tissue															Oysters removed from Carancahua Bay readily accumulated mercury when
(n=15)	55.7+ -	1.49+ -	73.8+ -	935+ -	6203+ -	549+ -					placed in Lavaca Bay.  Mercury accumulaton was rapid through the first 14
		2.0		4		4.7		36		260		43						days of exposure and leveled off with time (Fig. 2).  The rate of Hg
																		accumulation between days 0 and 14 averaged 70 ppb Hg per day.  From day
Detection	6		0.4		10		90		680		110						15 to 51 mean daily Hg uptake ranged from 0 to 10 ppb.  The Hg levels in the
Limit																		control oysters from Carancahua Bay did not significantly change over the 51-
__________________________________________________________________________________					d experiment when caged in Keller Bay.  The GLM procedure showed a
NC=not certified																significant (p<0.05) difference in Hg levels between sites and days collected.

																		The LSMEANS test showed that Hg concentrations in oysters caged in
distilled-deionized water, weighed, freeze dried, and homogenized before						Lavaca Bay on days 7, 14, 21, 36, and 51 were all significantly higher than
analysis.  All oysters were individually digested according to a modification						day 0 at p<0.05, while the Hg levels on days 14, 21, 36, and 51 were not
of the USEPA 245.1 (USEPA 1990) method and analyzed for mercury by							significantly different from one another.
cold vapor atomic absorption spectrophotometry (Hatch and Ott 1968).
Samples were additionally analyzed for Ba, Cu, Fe, P, and Zn using a							The results of the depurations study showed that contaminated oysters released
modified Applied Research Laboratories, Inc. (ARL) SpectraSpan VI								Hg when placed in an uncontaminated environment, Keller Bay (Fig. 3).  The
Direct Current Argon Plasma (DCP)Emission Spectrophotometer following							average Hg level dropped from 1660 + - 363 ppb on day 0 to 550 + - 416 ppb
ARL's instructions (ARL 1991).  Every digest (about 30 samples) included						on day 51.  The rate of Hg depuration varied throughout the experiment.  The
two aliquots of the reference material, 1566a Oyster Tissue, certified by the						rate was highest on days 14 to 21, averaging a loss of 72 ppb Hg per day.
National Bureau of Standards.  The certified and experimental values from the						According to the LSMEANS test, concentrations in oysters caged in Keller
1566a Oyster Tissue and the detection limits for each element are listed in						Bay on days 21, 36, and 51 were significantly lower than Hg levels in oysters
Table 1.																	from North Lavaca Bay transplanted to Keller Bay on day 0 at p<0.05.




						466																		467
																
																					



Table 2.  Correlations among variables measured in the oyster accumulation							showing that Hg contaminated is a continuing problem in Lavaca Bay and
and depuration experiments and the natural populations in Keller (KB) and							that the Hg is readily available for bioaccumulation by oysters.
Lavaca Bay (LB).  Upper, Spearmans rho; lower, P value

Variables		Accumulatons		Natural Population		Depuration						Positive correlatons between Cu and Zn, Zn and P, and Ba and Fe were
			KB	    LB		KB              KB		KB          LB	  				found in every experiment (Table 2).  Copper and phosphorus were positively
																			correlated in every oyster group except the natural population from Keller
Cu and Zn	  0.83100     0.81849      0.91104        0.87307	   0.89350      0.82946					Bay.  A positive relationship between P and Fe and a negative correlation
            (<0.0001)   (<0.0001)    (<0.0001)      (<0.0001)      (<0.0001)    (<0.0001)					between Hg and oyster dry weight were found in several experiments.
																			Correlations were also seen between Hg and Cu, Hg and Zn, and Cu and Zn
Zn and P	  0.40244     0.42855      0.28371        0.40736        0.32464      0.37663					in oysters from Lavaca Bay, i.c., those collected for the depuration
             (0.003)     (0.001)      (0.04)         (0.002)        (0.02)       (0.005)					experiment and the natural population of oysters from Lavaca Bay.

Ba and Fe	  0.64172     0.62662      0.60290        0.60290        0.68725      0.49675					Positive relationshiops between Cu and Zn in bivalves such as those found
             (0.0001)   (<0.0001)    (<0.0001)      (<0.0001)      (<0.0001)    (<0.0001)					here have been noted in previous studies (Paez-Osuna and Marmolejo-Rivas
																			1990a, Marcus and Thompson 1986, Wright et al. 1985, and Paez-Osuna and
Cu and P      0.37744     0.41719        NS		0.36245        0.36627      0.49388					Marmolejo-Rivas 1990b).  Copper and zinc are both biologically active
             (0.005)     (0.002)                     (0.002)        (0.007)     (<0.0001)					elements, but the reason for their strong correlation is not understood.
																			Previous work (George and Pirie 1980)found that Zn transferred in the
P and Fe      0.35252      NS          0.28380          NS           0.41407      0.33303					plasma of Mytilus cululis was mostly associated with granules that also
             (0.01)                   (0.04)                        (0.002)      (0.01)					contained FE, S, P, K, and Ca.  Others have indicated that M, edulis
																			sequesters Zn and Fe in lysosomes in various cell types (Lowe and Moore
Dry Wt.	   NS        -0.40646     -0.48637          NS          -0.46336     -0.38954					1979).  George et al. (1978) found Zn and Cu were immobilized in individual
and Hg		       (0.002)      (0.0003)                      (0.0004)     (0.004)                          granular amoebocytes; granular cells whih contained Cu and Zn were present
																			in Ostrea edulis, O, angasi, and C, gigas.  It is believed that oysters
Hg and Cu	   NS          NS            NS           0.55418        0.66808      0.29423					concentrate Cu, Zn P and other metals in granules to detoxify and change
								    (<0.0001)      (<0.0001)	  (<0.0001)					them to an excretable form (George and Pirie 1980, george et al. 1978).  The
																			correlatons between Cu and Zn, Cu and P, and Zn and P found in this study
Hg and Zn	   NS          NS            NS           0.56905        0.70215      0.43221					could be related to granular formation in C, virginica, but no documentation
                                                    (<0.0001)      (<0.0001)    (<0.0001)					of this was obtained.

Cu and Fe      NS          NS            NS           0.26899        0.49198      0.37663					The relationship among the elements Hg, Zn, and Cu may be a result of the
                                                     (0.05)         (0.0002)     (0.005)					high Hg concentrations in the water and sediment in Lavaca Bay.  Perhaps Cu
																			and Zn function in protective mechanisms in the detoxification of Hg, in C,
																			virginica.  Another possible explanation is that Lavaca Bay oysters contain
NS = Not significant																more metal-binding granules or low molecular weight binding proteins,
																			metallothioneins, which could detoxify the metals (Lobel and Payne 1984).
    	            																The strongest correlation between the three elements was found in oysters in
The average oyster living in the transplant sites in Lavaca and Keller Bays							the depuration study, where Cu and Zn closely followed the trend of
contained 2068 + - 676 ppb Hg and 354 + - 124 ppb Hg respectively.  The								decreasing Hg with time.
Carancahua Bay oysters caged in Lavaca Bay for the accumulation experiment
increased dramatically in Hg concentraton but did not reach the high average							Acknowledgments.  Research supported in part by Texas A&M University
Hg levels in the natural population of oysters in Lavaca Bay.  Similarly,							Seagrant Program, Institutional Grant #NA89aa-d-sg-139.  The authors
oysters caged in Keller Bay for the depurations experiment decreased in Hg							also thank the TAMU trace metal laboratory group for their invaluable help
from 1660 + - 363 to 550 + - 416 but did not acquire the low Hg concentrations						with field work.
found in the natural population of oysters in Keller Bay.

The transplant experiments clearly show that C virginica rapidly accumulated							REFERENCES
mercury when placed in a contaminated environment, Lavaca Bay.
Furthermore, mercury-contaminated C virginica from Lavaca Bay were								ARL (1991) DIRECT CURRENT PLASMA (DCP) optical emission
found to quickly depurate Hg when placed in an uncontaminated									    spectrometric method for trace elemental analysis of water and wastes
environment, Keller Bay.  Although the initial rate of Hg uptake was much							    method AES0029.  Applied Research Laboratories
faster than was the release, the oysters in the accumulation and depuration							George SG and Pirie BJS (1980) Metabolism of zinc in the mussel, Mytilus
experiments both changed average Hg levels by about 1000 ppb over the 51-d							    edulis (L): a combined ultrastructural and biochemical study. J Mar Biol
experiment.  The results of this study confirm earlier work (Riegal 1990)							    Assoc UK 60: 575-590


						468																			469
 	





				George SG, Pirie BJS, Cheyne AR, Coombs TL, and Grant PT (1978)
					Detoxification of metals by marine bivalves:  an ultrastructural study of the
					compartmentation of copper and zinc in the oyster Ostrea edulis.  Mar Biol
					45: 147-156
				Goldberg ED, Koide M, Hodge V, Flegal AR and Martin J (1983) U. S.
					Mussel Watch:  1977-1978 results on trace metals and radionuclides,
					Estuarine Coastal Shelf Sci 22:  395-402
				Hatch WR and Ott WL (1968) Determination of sub-microgram quantities of
					mercury by atomic absorption spectrophotometry.  Anal Chem 40:  2085-
					2087
				Huddle N, Reich M, and Stiskin N (1975) Island of dreams:  Environmental
					crisis in Japan.  Autumn Press, New York
				Lobel PB and Payne JF (1984) An evaluation of mercury-203 for assessing
					the induction of metallothionein-like proteins in mussels exposed to
					cadmium.  Bull Environ Contam Toxicol 33:  144-152
				Lowe DM and Moore MN (1979) The cytochemical distribution of zinc (Zull)
					and iron (FE III) in the common mussel, Mytilus edulis, and their
					relationship with lysosomes.  J Mar Bio Assoc UK 59:  851-858
				Marcus JM and Thompson AM (1986) Heavy metals in oysters around three
					coastal marinas.  Bull Environ Contam Toxicol 36:  587-594
				Paez-Osuna F and Marmolejo-Rivas C (1990a) Occurrence and seasonal
					variation of heavy metals in the oyster Saccrostrea iridescens.  Bull
					Environ Contam Toxicol 44:  538-544
				Reigel DV (1990) The distribution and behavior of mercury in sediments and
					marine organisms of Lavaca Bay, Texas.  December 1990
				SAS Institute Inc. (1985) SAS User's Guide:  Statistics, Version 5 Edition.
					SAS Institute Inc.
				TWQB Texas Water Quality Board (1977) Water Quality Segment Report for
					Segment No's 2453 and 2454 Lavaca and Cox Bays.  TWQS-21
				USEPA (1990) Contract Laboratory Program Statement of Work for
					Inorganics Analysis.  Document Number ILM01.0
				Wiles, K.  (1993) Personal communication on closure of Lavaca Bay to
					fishing.  Texas Department of Health, Shellfish Sanitation Control
					Division.  Austin, TX
				Wright DA, Mihursky JA, and Phelps HL (1985) Trace metals in Chesapeake
					Bay Oysters:  Intra-sample variability and its impliations for
					biomonitoring.  Marine Environ Res 16:  181-197.

				Received December 30, 1992; accepted March 1, 1993










									470





                                                       


















                           Reprint 7

            Trace Metal Chemistry of Galveston Bay:
                   Water, Sediment and Blota


                 John W. Morse, Bob J. Presley,
                      and Robert J. Taylor


















                              1-59





							Marine Environmental Research 36 (1993) 1 37





							  Trace Metal Chemistry of Galveston Bay:
								  Water, Sediments and Biota



						    John W. Morse, Bob J. Presley, Robert J. Taylor

				      Department of Oceanography, Texas A&M University, College Station
                                                     Texas 77843, USA

							  Gaboury Benoit* & Peter Santschi

				  Department of Marine Sciences, Texas A&M University at Galveston, Galveston
                                                        Texas 77553, USA



					(Received 5 Septemter 1991; revised version received 30 January 1992
								  Accepted 5 February 1992)


										ABSTRACT

					Galveston Bay is the second largest estuary in Texas.  It receives major
					urban runoff from the Houston area, its major river drains the Dallas-
					Ft Worth Metroplex, and the area surrounding the Bay is intensely
					industrialized, with chemical and petroleum production being especially
					prominent.  Consequently, there are serious concerns about the possible
					contamination of the Bay and previous studies have indicated toxic metals
					at elevated concentrations (e.g. NOAA, 1989a).
					  We have conducted an exgtensive investigation of Galveston Bay trace
					metals, in which their distribution in the water column, oysters and sedi-
					ments were determined.  Results of the water column and oyster analyses
					indicate that metal levels in open areas of Galveston Bay are currently
					similar to those in more pristine bays elsewhere.  Industrial metal inputs to
					the Bay have not led to greatly increased concentrations in water, sedi-
					ments and biota.  However, the sediment analyses indicated that such
					inputs may have been significant in the past.  Total Cu, Zn, Pb, and
					Ag concentrations in the waters, determined by state-of-the-art clean

				* Present address:  Yale School of Forrestry and Environmental Studies, Sage Hall, 205
				Prospect St., New Haven, Connecticut 06511, USA

											
				Marine Environ.  Res. 0141-1136/93/$06.00 1993 Elsevier Science Publishers Ltd. England
				Printed in Great Britain






2		J.W. Morse, R. J. Presley, R. J. Taylor, G. Benoit, P. Santschi								Trace metal chemistry of Galveston Bay              3

	techniques, are 1. 2-7, 0-3, and 0-0006 pg liter, respectively, and are					  The combination of large population, high industialization, shallow  
	mostly regulated by the dynamcs of sediment suspension and settling.					depth and restricted water exchange gives Galveston Bay the potential
	This leads to a correlation of particulate trace metal concentration with				for serious trace metal contamination problems.  Such problems have,
	the suspended particulate matter (SPM) concentrations, and trace metal					however, not been well documented.  Hann & Slowey (1972) showed sedi-
	enrichment in particles at low SPM concentrations.  Forty-four percent of				ments in the uper, confined parts of the Houston Ship Channel to be
	the individual sediment sampling sites exhibited an anomalous concentra-				highly enriched in several trace metals and this has been confirmed by
	tion with respect to at least one of the metals studied and about half of				yearly sampling by the Texas Water Quality Board and Texas Water
	these sites were directly associated with dredge spoils.  The study also indi-			Commission (TWC) since 1974 (Texas Water Commission, 1987).  How-
	cated that many of the metals are significantly converted to a coprecipitate				ever, sediment from the ship channel where it crosses the open Galveston
	with pyrite in the top 10 cm of sediment.										Bay did not appear to be contaminated in these early studies.  TWC ana-
																	lyses for trace metals in Houston Ship Channel water show a decline in
																	all metals between 1974 and 1986 but the quality of the data is in ques-
					INTRODUCTION										tion, so no firm conclusions can be reached.  The only reliable previously
																	published data for dissolved trace metals in open Galveston Bay waters
	Galveston Bay, with a surface area of 1600 km', is one of the largest em-				are thought to be those of Tripp (1988) who determined only As and Sb
	bayments on the US coastline.  The Bay water is, however, very shallow,					concentrations.  These were both near normal seawater values in the open
	averaging only about 2 m in depth and is largely cut off from the Gulf of				Bay but As was enriched by up to a factor of five in the Houston Ship
	Mexico by the Bolivar Peninsula and Galveston Island.  Tides, which av-					Channel and Sb was depleted there.
	erage about 40 cm in height, thus exchange water primarily through a					  One of the feared effects of contaminant inputs into coastal embay-
	channel between these two land barriers.  It is generally accepted that					ments is this buildup in water and sediments leading to accumulaton
	winds are often more important than tides in Bay circulation and water					and negative effects in biota.  For this reason, oysters and sedentary
	exchange (NOAA, 1989a), but exact current patterns in the Bay and the					organisms have been advocated as pollution biomonitors (Goldberg, 1975;
	residence time of water in the Bay with respect to exchange with the Gulf				Goldberg et al., 1983).  Bioaccumulation in benthic fauna can occur from
	of Mexico are not well known.  A mean residence time for waters in the					both dissolved and particulate forms.  Generally higher trace metal con-
	Bay of about 40 days has been estimated from its average salinity of 15					centration in either water or sediments lead to elevated eoncentrations in
	and an average river flow of 12 km year (Armstrong, 1982).							the biota, depending on the organism type, trace metal speciation and
	  The Trinity River supplies about 70% of the freshwater that enters the				solid carier phases.  Bioabailability of trace metals can be controlled by
	Bay, with the remainder coming from the San Jacinto River and from					many factors, for example, by the amount and speciation of iron in sedi-
	ungauged flows (NOAA, 0989a).  The Dallas, Ft. Worth Metroplex with its					ments.  An inverse correlation between bioaccumulation of Pb and bound
	4 million people is located 400 miles up the Trinity River from Galveston				Fe concentration in sediments has been found (Luoma & Bryan, 1978).
	Bay and is separated from the Bay by a large freshwater lake.  The Hous-				Therefore, a general overview of trace metal chemistry has to include all
	ton metropolitan area with its 3 million people is immediately adjacent to				three reservoirs (i.e. water, sediments, and biota) and has to pay special
	upper Galveston Bay and drains directly into it through the San Jacinto					attention to the chemical forms of Fe and other geochemical indicator
	River and the Houston Ship Channel.  The Houston Texas City Galves-					elements or key phsicochemical variables.  Very few such comparisons
	ston area is intensively industrialized, especially by the petroleum, petro-				which used state-of-the-art techniques for the analysis of all three reser-
	chemical and chemical industries.  For example, 30 50% of the US						voirs are available in the open literature.
	chemical production and oil refineries are situated around Galveston					  In order to obtain such an overview indicating possible heavy metal
	Bay.  This industrialization and the large population results in Houston				contamination in Galveston Bay, we have combined the results of three
	being the third largest seaport in the US in terms of total shipping ton-				studies.  These studies were of trace metal concentrations in both dis-
	nage.  Galveston Bay receives more than half of the total permitted					solved and particulate form in the water column (studies by Benoit and
	wastewater discharges for the state of Texas and a total of about 5 km					Santschi), concentrations in oysters (studies by Presley and Taylor), and
	year of wastewater input.												their form and distribution in sediments (studies by Morse).

    
	





4		J. W. Morse, R. J. Presley, R. J. Taylor, G. Benoit, P. Santschi							Trace metal chemistry of Galveston Bay			5


						METHODS

Water column-associated metals

Water samples for trace metal analysis were collected in summer and fall									 Trinity River
1989, along a transect from the Trinity River near the town of Anahuae,				Houston		|						
through Trinity and Galveston Bays, and out to the Gulf of Mexico                                           |
(Fig. 1).  Samples were not collected in the Houston Ship Channel/San							N
Jacinto arm of the Bay, but water from this source would have been							|
included as an admixture, especially in higher salinity samples.  The data						|
do not reflect a truly synoptic picture of the Bay system for eigher collec-     							     	Trinity Bay
tion for two reasons.  First, the size of the Bay made it impossible to
collect across the entire salinity gradient in a single day.  Second for the
summer collection, additional samples were collected during a trial run
two weeks before the other samples.
  Salinity was monitored using a refractometer, and samples were col-							  Galveston Bay
lected in salinity intervals of approximately 5%.  The refractometer had a
precision of about + or - 1 and reported salinities were measured in the labor-		Clear Lake
atory by argentometric litraton (Amer. Public Health Assoc., 1985).
Salinity sometimes changes rapidly and unpredictably over short dis-													East Bay
tances, at times decreasing locally in the seaward direction.  Likewise, tur-
bidity is very patchy.  To help verify that samples collected at a given
station were drawn from a discrete water mass, salinity was checked peri-
odically during sample collection.
  For measurements of trace metals in water column samples, ultraclean
techniques were used during all stages of sample collection, transport,															O
handling, processing, and analysis (Patterson & Settle, 1976).  A separate													     C
sample was collected by peristaltic pumping through a 0.4 um Nuclepore														    I
filter for measurement of salinity, suspended particulate matter, alkalin-													   X
ity, and DOC.																							  E
  Immediately after return to shore, water samles were preserved by                                                                                    M
acidification with 2 ml ultrapure HNO, per liter of seawater within a							                                        of  
portable laminar-flow clean bench.  Filters were unloaded from their										Galveston      	    
Teflon assemblies and transferred to acid-cleaned 15 ml screw-cap vials.                                                                           F
Filtered water samples were digested in their original bottles using the												  L					       	         				
preservation acid and ultrasonification for 60 min at 60C.  Filters were                                                                         U            
digested in their original vials using 10 ml of 0.5% HNO, and the same                                         West Bay                         G
heand sonification.														
  Extraction columns consisted of a 2 cm bed of silica-immobilized							Fig. 1.  Locations of sampling sites in Galveston Bay.  Solid circles are water column				            	
8-hydroxyquinoline (Sturgeon et al., 1981: Marshall & Mottola, 1983)                                        sites.  Numbers are sediment sites. Leters are oyster sites. A=Galveston Bay Yacht Club
contained in a 1.5 cm diameter glass chromatography column connected							(GBYC):  B = Todd's dump(GBTD): C = Hanna Reef (GBHR: D = Confederate Reef
to a 500 cm diameter glass reservois.  The column was precleaned by passage of						(GBCR): E=Ship Channel (GBSC).
		  
  




6	J.W. Morse, R.J. Presley, R.J. Taylor, G. Benoit, P. Santschi										Twice metal chemistry of Galveston Bay					7



approximately 300 ml of a solution 1 M in HCI and 0-1 M in HNO,				  Alkalinity and salinity were measured by titrtion, DOC by the wet
(Seastar Brand).  The concentration of zinc in the effluent was monitored		digestion method (persulfate phosphoric acid), and suspended particulate
until it nearly matched the added acid.  A sample of the final acid rinse		matter (SPM) by gravimetry.  Wet digestion may not quantitatively
was collected and measured for a column blank for all metals, though			measure dissolved organic carbon (DOC) in open ocean waters
this was usually negligible.  The column was rinsed with 10 ml of 18		      (Sugimura & Suzuki, 1988), but we believe it gives reliable results
Mohm water to remove traces of acid.  Immediately before preconcentra-			for qualitatively different DOC found in estuaries.  Virtuall all SPM
tion, aliquots were decanted in a clean bench and litrated to determine			analyses were measured in duplicate.  Here, we only report selected
the amount of ultrapure NII4OH required to adjust the pH to 8-0 + or - 0.5.		results as they relate to dediment and oyster data.  A full account of these
Approximately 200 ml of seawater sample (the entire 10 ml of digestion			data will be given elsewhere (Benoit et al., 1992). 
solution was used for filters) was passed through the column, which was
then rinsed with 10 ml ultrapure water to remove sea salts.  Metals were					Oyster-associated metals
then cluted with 15 ml of 1 M HC/10-1 M HNO and collected in a 15 ml
acid-cleaned plastic vial tht was checked for contamination by rinsing			Oysters (Crassostrea virginica) were collected at six different sites in
with the same acid and testing for Zn. 								Galveston Bay during 1986-90 as part of the National Status and Trends
  Lead, Cu, and Ag were measured in duplicate in acid-washed Teflon			Program (GERG, 1990).  Each site was on an identifiable oyster reef
autosampler cups in the graphite furnace of a Perkin Elmer Zeeman 5100              (Fig. 1) and at each, twenty oysters were taken from each of three
atomic absorption spectrophotometer equipped with Zeeman back-                      stations, the stations being 100-500 m apart. Each site was sampled once
ground correction, pyrolized furnace tubes and L'vov platforms.  Injec-             each year, except two of the sites (GBOB and GBSC) were not sampled
tion volumes were 40 pl for Cu and 150 pl (3 x 50 pl) for Ag and Pb.                during the first two years. The twenty oysters from each station were
Zine was measured by manual injection of 10 pl since the autosampler                combined and analyzed as a single sample each year.
introduced unacceptably high blanks of unknown source.  Manual injec-                 Oysters were usually handpicked from exposed reefs, but in deeper 
tions were repeated until reproducible absorbance readings were obtained            water they were taken by dredge or tongs. In most cases stations were
and verified (typically 3 to 5 injections.)                                         located hundreds of metres away from obvious point sources of contami-
  Column yields were monitered by parallel measurement of certified                 nant imputs such as industrial discharges in an attempt to characterize
reference seawaters (CASS-2, S=29.2%, or SLEW-1,S=11.6". Research                   large areas of Galveston Bay, rather than to identify specific point
Council of Canada) for one out of every five columns.  Silver column                sources. The new sites added in year three were, however, selected to be
yields were determined on spiked seawaters, since the seawater reference            closer to industrial areas or population centers than were the original
materials are not certified for silver. Concentrations were calculated by           four sites. Stations were reoccupied as closely as possible each year, both
correcting for metals in the elution acid, the column blank, and column             in time and space.
yield (typically near 90%). Bottle blanks, determined on distilled water               Frozen oysters were returned to the laboratory where they were
collected in the field using the same filtration system, were negligible.           brushed to remove mud from the shells and allowed to thaw. They were
Column yields had a standard deviation close to 20% and introduced                  then opened under clean room conditions using a stainless steel oyster
most of the uncertainty in the final calculated concentrations. Duplicate           knife. The tissue was washed sparingly with distilled-deionized water to
samples (20% of collected samples) and replicate laboratory analyses                remove any adhering mud and was put into a 500 ml Teflon jar. When
(10% of measurements) agreed with in the calculated uncertainties.                  the jar was approximately one-third full, or when all twenty oysters from
   We believe that our measurements are reliable for several reasons: (1)           a given station had been added, three solid Teflon balls of 3.5 cm dia-
state-of-the-aret clean techniques were used throughout: (2) the method             meter were added. The jars were tightly closed and were put into plastic
was checked frequently against certified reference seawaters: (3) the con-          Ziplock bags. The jars were then loaded into an industrial paint shaker
centration ranges were measured are similar to values found by careful investi-     and were shaken vigorously for 15-20 min to completely homogenize the
gators working on other estuaries; and (4) the trends in the data are               samples. An aliquot of the combined and homogenized sample was 
geochemically reasonable, i.e. they correlate in a simple manner with               freeze-dried, re-homogenized by ball milling in plastic, and weighed into
anneillary key physicochemical variables.                                           a digestion vessel.








                                    8             J.W. Morse, R.J. Presley, R.J Taylor, G. Benoit, P. Santschi                                                    Trace metal chemistry of Galveston Bay
                                      The digestion vessels were 60 ml capacity screw top "bombs of PF                                       banks are widespread. Because of the great heterogeneity of this environ-                                  Teflon (Savillex Corp., Minnetonka, MN model 561). Digestion of                                               
                                    approximately 200 mg dry weight samples of oyster tissue used 3 ml of						   ment, anything short of a monumental sampling effort will not yield a	
                                                                                                                                             detailed picture of distributions in the Bay. Whether such an effort is
                                    4 to 1 mixture of ultra-pure nitric and perchloric acids. The samples we                                 justifiable is open to question because major storms, including hurri-
                                    first allowed to pre-digest for 2 3  in the mixture on a warm hotpla                                     canes, which are common in this area, cause substantial redistribution of
                                    while the bombs were covered with Teflon watch covers. The bowl                                          the sediments. With this in mind, sites were chosen throughout Galve-
                                                                                                                                                                                        
                                    were then tightly closed to a constant torque (2.5 kg-m) with matchin                                    ston Bay that were deemed reasonable representative, Sites associated
                                    screw caps and were placed in an oven at 130'C for 8 h. After remov.                                     with dredged areas and that have a potential for abnormal metal concen-
                                    from the oven and cooling, 20 ml of distilled- deionized water with added                                trations were given special emphasis. Sampling locations are shown in
                                    The bombs were weighed and from the known empty bomb weight an                                           Fig. 1.
                                    final solution density (1-04 g ml') an exact final solution Volume W;                                       Samples were collected from the RV Roman Empire either by hand
                                    calculated. This and the sample weight were used to calculate a dilutio                                  coring with a precleaned plastic core tube or with an epoxy-coated grab
                                    factor for each sample.                                                                                  sampler in deeper waters. Only the top -10 cm of sediment was used
	                              Two blanks and two refrences materials were digested with every s                                        and it was homogenized upon collection in sealed bags from which air
                                    of 20 40 samples. Reference material used included National Institu                                      was excluded to prevent oxidation. This sampling depth was used
                                    of Standards and Technology (NIST, formerly NBS) 1566 oyst                                               because it represents 'near surface' sediments and the sandy nature of
                                    tissue. National Institute for Enviromental Studies, Japan (NIES) muss,                                  many of the sediments often precluded sampling much deeper. The
                                    tissue, EPA trace metals in fish standard. National Research Counc                                       homogenized bag sample was immediately divided between two pre-
                                    of Canada (NRCC) DOLT-1 dogfish liver tissue and it Texas A&M                                            cleaned plastic bottles which were filled to the top to exclude air, capped
                                    University (TAMU) house stanard oyster tissue. Repealed analysis                                         and scaled with electrical tape. One bottle was quick-frozen on dry ice
                                    these reference materials and participation in several intercalibrtio                                    for sulfide and metal analyses.
                                    exercises organized by Dr Shier Berman of the NRCC give an estimat                                           A portion of sediment was weighed and freeze-dryed to determine water
                                    of 10% or better for both the precision and accuracy of the data report                                  content.Porosity was calculated by using 2.5 as the solid density and correcting for the weight loss of pore water. Sediment grain-size distributions -                                    here.                                                                                                                                              All data reported here were obtained by atomic absorption spectr                                         were determined by wet sieving following the method of Folk (1968).
                                    metry (AAS). Flame AAS was used for Cu. Fe. and Zn which exhib                                          Organic carbon and carbonate carbon were determined with a LECO
                                    high concentrations in oysters, cold vapor AAS for mercury and graphit                                  Carbon analyzer (CR12) in which a finely ground sample is combusted at
                                    furnace AAS (Perkin-Elmer Corp. model 3030 with Zeeman backgroun                                        1350"C. A portion of the sediment was acidified with 2 ml of 6 NHCI to
                                    correction) for tile remaining elements. Some samples of freeze-drie                                    remove carbonate carbon and dried on a hotplate for 12 at -70'C.
                                    oyster tissue were also analyzed for some elements by neutron activatio                                 This sample was then combusted in the LECO carbon analyzer to yield
                                    analysis (NAA) which required no sample pre- or post-treatment. Agre                                    organic carbon content.The carbonate carbon was then determined from
                                    ment between AAS and NAA was good (+10%) for elements analyzed to                                       the difference between the total and organic carbon. The precision was
                                    both techniques.                                                                                        1% (1 SD). A LECO carbon standard of 0.98 wt% C was used for
                                    The samples were analyzed for Ag. As. Cd, Cr, Cu. Fe, Hg, Mn. N                                         standardization.
                                    Pb, Se, Si, Sn, and Zn. In addition, temperature. salinity and related en                                  Sedimentary iron sulfide minerals were operationally defined as acid
                                    vironmental parameters were measured as were size, sex, parasite pres                                   volatile sulfide (AVS) mid Pyrite.AVS was extracted from sediments
                                    ence and indicators of health of the oysters (see GERG, 1990).                                          using a cold HCI (6 N)+ SnCl2 (2%) method (Cornwell & Morse, 1987).
                                    

                                                                                                                                            Pyrite was determined from the difference between AVS and the total
                                    Sediment-associated metals                                                                              reduced sulfur (TRS) concentrations. TRS was extracted using a boiling
                                                                                                                                            Cr(11)+ acid method (Zhabina & Volkov, 1978, as modified by Canfield
                                    The sediments of Galveston Bay are highly Variable, with major viria                                    et al., 1987). The Cr(11) + acid method has been demonstrated to
                                    tions in grain size occurring on a small scale. Also. oyster reefs and spoi                             extract Pyrite sulfur effectively and specifically after removal of
 


10            J.W. Morse, R.J. Presley, R.J. Taylor, G. Benoit, P. Santschi                   trace metal chemistry of Galveston Bay                 11 



metastable iron sulfide minerals by AVS extraction (Canfield et al. 1987). Also, this method has been demonstrated to extract none of the 
organic sulfur from sulfur-containing compounds or natural organic matter, thus, eliminating the interference from organic sulfur(see Can-
field et al., 1987). The concentration of hydrogen sulfide evolved by these methods was determined by potentiometric titration with Pb(CIO4)2.
The detection limit of potentiometric titration was- 1 amol g 1, and the precision was 5% (1 SD).
   Metels were extracted from the sediments using teaching techniques. Freeze-dried portions of the frozen samples were subjected to a series of
teaching procedures in order to separate sedimentary pyrite from the bulk sediment. Briefly, the sequential extraction procedure involves diges-
tion of the sediment sample with 1 m HCI (reactive fraction). 10 m HF (silicate fraction) and concentrated HNO1 (silicate fraction) and concentrated
HNO1, (pyrite fraction). A more complete explanation of the sequential extraction procedures and the development of the separation method is given
in Huerta-Diaz & MOrse (1990). Additionally, frozen samples were extracted with the 1 m HCI results. 
   Trace metals (as,Cd,Cr,Cu,Fe,Hg,Mn,Mo,Ni,Pb and Zn) were determined by flame atomic absorption(FAA) using a Perkin-Elmer model 2380 spectrophotometer.
Metals below the detection limit of this instrument were analyzed by direct injection into a Hitachi model 170-70 graphite furnace atomic absorption 
(GFAA) spectrophotometer with Zeeman background correction. The analytical precision (relative standard deviation) was normally between 5 and 10% for
flame atomic absorption analyses and between 10 and 15% for graphite furnace atomic absorption analyses. Salt matrix effects for As determination by GFAA
were partially overcome by using a Ni Pd ascorbic acid matrix modifier (Robert Taylor, pers. comm.) Determination of Pb by GFAA in samples containing high
Fe/Pb ratios (>250) was carried out following the procedure developed by Shao & Winefordner (1989). Mercury was determined with a Laboratory Data Control UV
monitor equipped with a 30 cm path length cell, using the well-known cold vapor technique. For samples suspected of having high dissolved organic matter (DOM)
concentrations. Hg was measured after destruction of the DOM with bromine monochloride. Detection limits were calculated as 2.5 times the standard deviation
of the reagent blank (e.g.Kaiser, 1970; Bruland et al., 1979; Kremling, 1983). All reagents used were ACS reagent grade or better. Milli-Q water was used for 
the preparation of all aqueous solutions. Acidic working standard solutions were always freshly prepared. All materials were carefully cleaned using established
acid teaching procedures. The use of the sequential extraction procedures precluded comparisons with standard reference materials for which only total metal con-
centrations are generally available.  


							RESULTS	


Because of the large number (1000s) of analyses done as part of this study, original analytical data are generally not given in this paper. These data are available 
from the authors upon request.

Trace metals in the water column

Samples were collected over salinities ranging from 0.1% to 27.4%, and particulate matter levels from 2.4 to 48.4 mg liter 1(Fig.2). Particulate matter did not show 
the same trend with salinity on the two sampling dates. In August, there was a mid-salinity SPM maximum, while in October, there was an SPM minimum at intermediate 
salinities. In fact, the two curves are almost inverses of each other. The variations over time at a given location probably reflect different levels of wind-driven 
mixing and turbulence, and subsequent sediment entrainment in the water column of this shallow estuary.
   DOC levels in the fresh water samples were 5.5+1.4 and 5.3+0.2 mg C liter', while in the Gulf and member they were 0.1 + 0.3 and 0.29+



						SALINITY (%0)
Fig. 2.  Suspended particulate matter concentration as a function of saliity. SPM probably reflects local wind stress induced resuspension of bottom sediments.   		                       


12			J.W. Morse, R.J. Presley, R.J. Taylor, G. Benoit, P. Santschi                    Trace metal chemistry of Galveston Bay        13



.14 mg litre'. DOC showed very consistent behaviour on the two dates, decreasing non- conservatively (curve concave-upwards) with salinity in
both cases. Therefore, a sink for DOC in the intermediate salinity range is indicated for Galveston Bay. This is consistent with previously
observed removal of DOC via flocculation with increasing ionic strength in other estuaries (Boyle et al., 1977). Alkalinity was nearly constant at
about 2 meq liter' at all salinities in the estuary.
   Results of trace metal measurements are summarized in Table 1 and illustrated in Fig.3 as a function of SPM. In general, trace metal concen-
trations were 5 to 10 times higher than open ocean values (Boyle & Huested, 1983; Bruland & Frank, 1983; Martin et al., 1983. Schaule & Patterson, 1983),
and are similar to measurements from other estuaries, conducted by careful analysts (c.g. Bewers & Yeats, 1978; Windom et al., 1983, 1985; Keeney-
Kennicutt & Presley, 1985; Mart el al., 1985; Shiller & Boyle, 1985; Valenta et al., 1986). Dissolved metals often did not show systematic variations with 
salinity, white particulate metal concentrations in the water column (pg liter' showed trends that were broadly similar to those of suspended particulate 
matter (mg liter')
   Zinc, Pb, and Cu each had similar concentration ranges on the two dates while dissolved Ag levels were significantly lower at the later date. In August
dissolved Ag averaged 5.6 + 2.2 mg liter', while in October it was 1.3 + 0.8 ng liter'. Particulate Ag dropped from 3.6 + 1.8 to 2.2 + 0.8 ng liter', but 
this is not a statistically significant change (Bevington, 1969). the change in dissolved Ag could result from high freshwater inputs in spring and summer
with Ag dilution 
in freshwater sources, or from a decrease in the organically complexed form of the metal. If the





							   TABLE 1
                 Summary of Trace Metal Data in the Water Column of Galveston Bay
			       Zn                Pb                Cu               Ag

			   Diss     Part    Diss      Part    Diss     Part    Diss     Part
	    Maximum     4.50	2.56	 0.133     0.530    1.41     0.39    8.9      5.9
          Minimum	    0.30    0.44   0.022     0.026    0.13     0.03    0.2      0.7
          Average     1.68    1.04   0.071     0.209    0.86     0.15    3.2      2.8
          SD          1.14    0.66   0.029     0.150    0.33     0.10    2.7      1.5
          n          17      20     19        19       21       19      20       15

      A single particulate sample gave the follwing values in pg liter'. Zn 6.85, Pb 0.36,
      Co 0.80, and Ag 21 ng liter'.This sample was assumed contaminated and not included in the compilation.
      Diss-dissolved, Part= particulate, concentrations are in pg liter; except Ag which is in ng liter'.



Fig.3. Metal concentrations in suspended particulate matter as a function of SPM concentrations in the water column. Note that metals have similar
concentrations in SPM and in average surficial sediments (dotted lines). Metal concentrations are higher at low SPM levels probably because more line-
grained sediments are suspended at such times.
lattef were true, it seems likely that Cu would change in  s similar manner. Systematic contamination with Ag alone seems improbable. Further study of
the seasonal concentration of dissolved Ag could resolve this question.

Trace metals in oysters

Oysters and other bivalves have been used as 'sentinel' organisms for assessing the contamination of coastal marine water bodies for almost


                                   14         J. W. Morse, R. J. Presley, R. J. Taylor, G. Benoit. P. Santschi




                                                                                                                                             15                                        Table 2

                                   twenty years. For example, Goldberg et at. (1983) report data for a                                           Summary Statistics for Trace Metal Concentrations in Galveston Bay and US Gulf of Mexico Oysters Collected for the NOAA NS&T                                                                                            
                                   USEPA-funded Mussel Watch program conducted in 1976 78 and the                                                                      Program in 1986-90 and for the EPA Mussel Watch in 1976-78. All Values in ppm dry weight
                                   current NOAA funded National Status and Trends (NS&T) program
                                   (NOAA, 1985, 1989b) is an outgrowth and extension of the Mussel                                                                         Ag     As     Cd     Cr     Cu     Fe     Hg     Mn     Ni     Pb     Se     Sn     Zn
                                   Watch concept. Bivalves are widely recognized as being responsive to                                          Galveston Bay
                                   changes in contaminant levels in the envoroment, good accumulators of                                           1986-90              2.77      4.50   4.33    0.53   165    275    0.078  15.9   1.89  0.71   3.42   0.29   3263
                                   metals, widely distributed along coasts and easy to collect and analyze.                                        SD                   2.42      1.08   1.58    0.44    61    142    0.066   8.1   0.64  0.45   0.88   0.22   1648  
                                   They integrate contaminant levels in the enviroment over weeks to                                             US Gulf of Mexico
                                   months and therefore allow areas to be compared even when sampling is                                           1986-90              2.24       9.69   4.20   0.55   156    320    0.142  14.8   1.64  0.69   2.99   0.23   2417        
                                   limited to a frequency of once or twice per year.                                                               SD                   1.59       7.00   2.46   0.42   107    243    0.156   8.8   1.29  0.93   1.33   0.16   1753
                                      Trace metal concentrations found inoysters collected along the Gulf                                        GB GOM                 1.23       0.46   1.03   0.96   1.06   0.86   0.55   1.08   1.16  1.03   1.14   1.24    135 
                                   of Mexico coastline during the first five years of NS&T were generally                                          Significance of t-test    
                                   similar to those reported in oysters taken from non-contaminated water                                          of means             <0.01      <0.01  0.64   0.63   0.44   0.11   <0.01  0.29   0.08  0.86   <0.01  <0.01  <0.01
                                   in other parts of the world (Presley et al., 1990). Only a few sites showed                                   US Gulf of Mexico
                                   obvious trace metal contamination and these were restricted geographi-                                        1976-78b                1.8        ----    4.6   ---   162    ----    ----  ----   2.7   0.9    ----    ----   1940
                                   cally such that nearby sites were usually unaffected. Abnormally high or                                      SD                      1.5        ----    2.6   ----  138    ----    ----  ----   1.4   0.9    ----    ----   1480                                    low values at a site did, however, usually repeat year after year suggest-
                                   ing local influences. Sites giving higher than average values for most                             
                                   metals were just likely to be far from populatin or industrial centres
                                   as to be near such areas.                                                                                     Crassotrea virginia: for Galveston Bay, n= 78 pooled samples of 20 oysters each; for GOM, n=874 pooled samples of 20 oysters each.                                          
                                      The oysters collected in Galveston Bay for NS&T were similar in trace                                      Crassostrea virginia: mean +1SD;EPA Gulf Mussel Watch: Goldbert et al. (1983).
                                   metal content to those collected elsewhere along the Gulf coastline, i.e.
                                   the oysters give no indication of generalized trace metal contamination in
                                   Galveston Bay.  This can be seen by comparing the overall averages
                                   (Table 2) for all years and all sites in Galveston Bay with those for the
                                   entire Gulf. The Galveston data include five sites sampled all four years
                                   and two sites sampled for two years. Three stations were sampled at each
                                   site resulting in almost 1500 Galveston oysters being analyzed over the 
                                   five year period. The Gulf data set includes more than 18000 oyster, as
                                   fifty sites were sampled all five years and an additional twenty sites for
                                   three years.  Thus, the averaged data are unlikely to be biased by a few
                                   abnormal individuals.
                                      The average Cd, Cr, Cu, Mn, and Pb in NS&T oysters from Galveston
                                   Bay differs by 10% or less from the Gulf-wide average. This difference is
                                   about the same as our analytical precision and is not significant at the 
                                   99% confidence level based on a 't-test'. Silver is 23% higher in Galveston
                                   Bay. NI is 16% higher and Se is 14% higher. A 't-test' of the significance of
                                   those figures shows that the Ni averages are not significantly different at the
                                   95% confidence level.  Although, the Se average for Galveston Bay oysters
                                   is significantly higher than the Gulf-wide average, it is not significantly
                                   different from the Texas Louisiana average. It differs from the Gulf-wide
                                   average only because of low Se oysters in MIssissippi and Florida.

                                   
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
                                                                                                                                                                                                 
                                  
                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           CIO
                                                                                                                                                                                                                                                                                                    

16    J.W. Morse, R.J. Presley, R.J. Taylor, G. Benoit, P. Santschi                          Trace metal chemistry of Galveston Bay                   17

	The high average Ag in Galveston Bay oyster is caused by a 300%                                        TABLE 3
enrichment found at a site on Confederate Reel in 1990. The enrichment                  Sediment characteristics C=clay; S=sand; s=silt; C=clay.
appears to be real because it was in all three of the twenty oyster pooled       ________________________________________________________________________ 
samples collected at that site. No cause for the enrichment can be sug-          Sample       Sand   Silt  Clay  <62pm  Class  Porosity  Organic-C  CaCO3  
gested, and if these samples are neglected NS&T Galveston Bay oysters                         (wt%)  (wt%) (wt%) (wt%)            (%)       (wt%)   (wt%)  
would have average silver content.                                               _________________________________________________________________________
	Arsenica and mercury in Galveston Bay oysters are less than one-half       GB1-1         25     32    43     75    SsC      79        1-16     0-33
the Gulf-wide average but the Gulf-wide averages are greatly influenced          GB1-2         66     17    17     34     S       64        0-41     0-76    
by several sites in southern Florida that produce oysters greatly enriched       GB1-3         65     11    24     35     S       62        0-35     1-37
in arsenic and mercury and by a site in Lavaca Bay, Texas which is en-           GB1-4         43     48    19     57    SsC      63        0-29     0-85    
riched in mercury. Oysters from other Texas and Louisiana bays are sim-          GB1-5         45     36    19     55     Ss      51        0-24     4-05    
ilar in As and Hg content to those in Galveston Bay.                             GB1-6         44     40    16     56    SsC      61        0-30     1-95
	Tin seems to be about 24% higher than Gulf averages in Galveston           GB1-7         78     14     8     22     S       51        0-18     2-68 
Bay, but Sn values are near the detection limit of the method used and a         GB1-8         75     17     8     24     S       52        0-19     1-08
24% difference may not be meaningful. Finally, Zn is 35% higher in               GB1-9         36     36    28     65    SsC      60        0-43     3-70
Galveston Bay oysters collected for NS&T than in Gulf-wide average               GB1-10        65     30     5     35     S       54        0-22     2-01
oysters. This difference is highly significant as the high Zu found in all oys-  GB1-11        93      5     2      7     S       45        0-07     0-70
ters leads to precise analytical determination and few analytical aritifacts.    GB1-12        93      4     3      6     S       26         --       --
Trace metals in sediments                                                        GB1-13        34     47    19     66    SsC      74        0-52    24-38
                                                                                 GB1-14        34     29    37     66    SsC      69        0-44     1-91
Sediment characteristics vary widely at the different study sites (Table 3).     GB1-15        87      9     4     13     S       54         --       --
This reflects the highly heterogencous environment in Galveston Bay and          GB1-16        93      4     3      8     S       49        0-15    11-86
the impact of man's activities, such as dredging and trawling for shrimp.        GB1-17        87      7     6     12     S       54        0-18     3-95
The sediments are generally poorly sorted mixtures of sand, silt and clay,       GB1-18        98      2     0      2     S       47        0-1      4-25
and exhibit major variations in mean grain size. Porosity averages 62            GB1-19        95      2     3      5     S       47        0-05     0-60
(+10)%.                                                                          GB1-20        36     36    28     64    SsC      51        0-11     7-87    
	The organic carbon content of these sediments is highly variabe aver-      GB1-21        57     12    32     43     CS      53        0-11    13-46
aging 0-42 wt% and ranging from 0-05 to 1-18 wt%. It is positively corre-        GB1-22        63     22    15     37     CS      50        0-14     2-46   
lated (r2=6-69) with the <62 on suze fractub if tge sediments. The               GB1-23        87      5     8     13      S      48        0-10     6-94
CaCO, content of the sediments is also highly variable averaging 3-9 wt%         GB1-24        75      8    17     25      S      57        0-22     1-37
and ranging from 0-33 to 24-4 wt%. It is not correlated with the <62 pm          GB1-25        40     20    31     51    SsC      67        0-41     1-26
size fraction (r2-0-00) and is dominantly present as shell fragments.            GB1-26        53     20    27     47    SsC      58        0-34     2-92
	Average trace metal concentrations are given in Table 4. Also included     GB1-27        60     13    27     40     CS      60        0-35    17-48
in this table are the range of trace metal concentrations. trace metal con-      GB1-28        59     14    27     41     CS      58        0-36     0-95
centrations normalized to the <62 pm grain size fraction, and the percent        GB1-29        20     37    43     79    SsC      73        0-67     3-16
of the metal in the total reactive fraction (here defined as 1 N HCI             GB1-30        88     10     2     11     S       54        0-18     1-77
extractable + pyrite-associated metal). The average concentrations are           GB1-31        56     16    28     44    SsC      65        0-46     2-07
similar to values observed in other estuaries (e.g. Naragansett Bay,             GB1-32         8     22    70     92     sC      73        1-11     2-14
Santschi et al., 1984; Baffin Basy, Huerta-Diaz & Morse, 1992) especially        GB1-33        27     30    43    272    SsC      76        0-77     2-58
when grain-size normalized values are used. This is further elaborated in        GB1-34        29     25    46     71    SsC      76        0-75     2-13
the Discussion section.                                                          GB1-35        42     18    40     58    SsC      69        0-61     1-42    
                                                                                 GB1-36         5     27    68     95     sC      78        1-18     2-55
                                                                                 GB1-37        36     25    39     64    SsC      80        0-79     6-67
                                                                                 GB1-38        65     22    13     35     sS      57        0-36     1-38
                                                                                 GB1-39        51     27    22     49    SsC      70        0-62     2-48
                                                                                 GB1-40        84      8     8     16     S       69        0-26     1-89
                                                                                 GB1-41         9     28    63     90     sC      77        1-07     2-64
                                                                                 _________________________________________________________________________
                                                                                 These are combined for other classes of sediment (e.g. Cs=Claycy silt) according to
                                                                                 Folk (1968).                                               

18  J.W. Morse, R.J. Presley, R.J. Taylor G Benoit, P. Sanschi                               Trace metal chemistry of Gulveston Bay                19
         
                              TABLE 4                                                                        TABLE 5
    Summary of Metal Concentrations in Galveston Bay Sediments                	     Data on Reduced Sulphur and Extent of Pyritization
__________________________________________________________________          	______________________________________________________________________________
Metal     Average         Range in       Average        % Reactive          	Sample	TRS		AVS		%AVS		Pyrite    DOP-FCD     DOP__1 N     
        concentration   concentration  concentration                          	   (pmol g')   (pmol g')    (pmol g')    (pmol g')    	
__________________________________________________________________         	______________________________________________________________________________
As	      56			23.98		125			42              	GB1-1		64.5		5-2		8-0	     29-7		0-43		0-55					
Fe      15 900	        1 570 40 200	35 200		30              	GB1-2		33-2		0-6		1-7	     16-3		0-27		0-45
Ct		37			4 W2		82			37              	GB1-3		42-4		0-6        20-0	     16-9		0-23		0-35		
Cu		 8			2 15		18			51              	GB1-4		41-1		4-6	     11-1	     18-3		0-28		0-43	
Hg	       0-08		   0-01 0-28	 0-19			98			GB1-5		45-6		2-1		4-6	     21-8		0-41		0-52
Mn       	605		   165 2 365	1 320			42			GB1-6		71-1		1-4		1-9	     34-9		0-44		0-68
Mo		41			25 79		   95			29			GB1-7		22-7		1-4		6-1	     10-6		0-25		0-53
Ni		26			 4 45		   58			28			GB1-8		28-9		4-5	     15-7	     12-2		0-29		0-52
Pb		25			12 46		   59			99			GB1-9		83-3		3-8		4-5	     39-8		0-44		0-61
Zn		55			6 116		  123			44			GB1-10	45-7		2-7		6-0	     21-5		0-55		0-73
_________________________________________________________________			GB1-11	12-3		0-3		2-5	      6-0		0-32		0-76
Concentrations are total in pg g . Concentration* concentration normalized	GB1-13     147-3		4-0		2-7	     71-6		0-76		0-79
to the average fraction of sediment (0-45) in the less than 63 pm grain-size	GB1-14     199-7		0-0		0-0	     99-9		0-77		0-77
range. Reactive-metal fraction = 1 N HCI extractable-metal + pyrite-metal.	GB1-16	24-8		2-1		8-4	     11-4		0-35		0-50
													GB1-17	18-4		1-9	     10-5		8-3		0-29		0-35
	All sediments were observed to be anoxic with the active sulphide min-	GB1-18	 7-9		0-4		4-7		3-8		0-16		0-24
eral formation occurring. Data on the concentrations of AVS and TRS.		GB1-19	 5-2		0-1		1-8		2-6		0-12		0-09
and th degree of pyritization (DOP) of iron using both citrate dithionite	GB1-20	23-0		1-4		6-1	     10-8		0-23		0-50
and 1 N HCI extration techniques to remove reactive-Fe are presented in		GB1-21	17-2		2-3	     13-6		7-4		0-10		0-24
Table 5. DOP is delined as (berner, 1970):						GB1-22	41-4		7-1	     17-2	     17-2		0-34		0-38
                                    Pyrite Fe						GB1-23	 7-0		0-6		8-7		3-2		0-17		0-28
                              DOP=								GB1-24	 8-5		0-3		4-0		4-1		0-27		0-21
                                   Pyrite Fe + Reactive Fe				GB1-25	28-8		0-4		1-5	     14-2		0-21		0-27
where pyrite-Fe is assumed equal to 0-5 (TRS AVS), based on the 1:2		GB1-26	64-6		4-8		7-4	     29-9		0-47		0-62
stoichiometry of FE:S in pyrite. The AVS concentration averages 3-6		GB1-27	21-2		1-2		5-8	     10-0		0-14		0-17
            and ranges from 0-1 to 16-3          TRS concentrations		GB1-28	43-3		0-4		0-9	     21-5		0-28		0-28
average 58-6            and range from 5-2 to 314-2             AVS		GB1-29	49-7		9-8	     19-8	     20-0		0-17		0-16
generally represents a small fraction of TRS averaging 7-6% and never		GB1-30	23-6		0-8		3-3	     11-4		0-27		0-12
exceeding 24   of TRS. Neither TRS nor the fractin of TRS as AVS are		GB1-31	88-7		1-9		2-2	     43-4		0-66		0-48
well correlated with the <62 pm fraction of the sediment (r2=0-25 and		GB1-32	58-9		9-8		16-7	     24-5		0-42		0-28
0-08, respectively)>										GB1-33	95-8		5-8		6-1	     45-0		0-62		0-52
	The DOP values determined by the citrate Jithionite and 1 N HCI		GB1-34     175-2		3-9		2-2	     85-6		0-50		0-41
methods are in good general agreement averaging, respectively. 0-35 and		GB1-35	65-5	     10-4	     15-8	     27-9		0-48		0-41
0-42. This is consistent with the findings of previous studies (e.g. Huerta-	GB1-36	56-9		7-7	     13-5	     24-6		0-29		0-22
Diaz & Morse. 1990). Because of difficulties in applying the citrate		GB1-37     314-2		4-0		1-3	    155-1		0-62		0-58
dithionite method when determining some trace metals of interest (e.g.		GB1-38	38-8		4-0	     10-3	     17-4		0-61		0-54
Zn), results using the 1 N HCI extraction method for charactyerizing the	GB1-39	62-6		1-6		2-6	     30-5		0-37		0-32
non-pyritized reactive fraction were used. The DOP (1 n HCI) of			GB1-40	38-5		0-9		2-4	     18-8		0-22		0-18
													GB1-41	68-8	     16-3	     23-7	     26-2		0-30		0-24

													Average	58-6		3-6		7-6	     27-5		0-35		0-42
													SD		60-1		3-6		6-2	     29-8		0-18		0-19

(Column 1)

20		J.W. Morse, R.J. Presley, R.J. Taylor, G. Benoit, P. Santschi

sediments is highly variable, ranging from 0.09 to 0.79.  The upper range
of values is indective that Fe may be approaching being the limiting
factor for pyrite formation in some of the sediments.
	In areas where sediment grain size varies substantially, such as Galve-
ston Bay, total metal concentrations (Table 4) by themselves often are
not particularly informative.  This is because the metals are often domi-
nantly associated with the fine-grained material and, consequently, varia-
tions in metal concentrations given in Table 4 may largely reflect grain
size differences (e.g. Trefry & Presley, 1976).  The correlation coefficients
(f) for the total reactive fraction of metals studied in Galveston Bay
with the <62 pm grain size fractions are: Fe = 0.08. Mn = 0.52, Ni =
0.66, Cu = 0.57, Zn = 0.73, Cd = 0.16, Pb = 0.47, Cr = 0.69, Mo = 0.18,
As = 0.00, and Hg = 0.08.  These relationships indicate that most metals,
with the exceptions of Cd, Mo, As, and Hg are dominantly associated with
the fine-grained fraction of the sediment.  The metals not well associated
with this fraction may be incorporated into the sediment by processes
other than simple sedimentation (e.g. diffusion of dissolved arsenate and
molybdate into the sediment followed by reduction and precipitation) or
be associated with fractions such as large carbonate particles.
	It is common in the study of trace metal geochemistry to attempt to
'normalize' concentrations by ratioing the trace metals to some other
more abundant chemical components such as Fe or Al.  Because Al was
not determined in this study, the correlations (r2) of total trace metal
concentrations with total Fe concentrations were calculated.  The results
are: Mn = 0.60, Ni = 0.79, Cu = 0.56, Zn = 0.88, Cd = 0.42, Pb = 0.46,
Cr = 0.90, Mo = 0.42, As = 0.01, and Hg = 0.06.  Mn, Ni, Zn, Cd, Cr,
Mo all exhibit significantly better correlations with Fe than with the fine-
grained fraction, whereas Cu and Pb exhibit about the same correlation
by both approaches.  Arsenic and Hg were the only metals exhibiting a
poor correlation with both grain size and Fe.
	The primary concern in this study is not with total metal concentrations,
but rather with the total reactive fraction which is operationally defined here
as reactive metal (l M HCI extractable) + pyrite-metal.  The citrate dithionite
extractable fraction was not used since the reagent is substantially con-
taminated with several of the metals of interest and in some cases
this fraction is not well analyzed by graphite furnace atomic absorption
spectrometry (see Huerta-Diaz & Morse, 1990, for discussion).  The con-
centration ratios of the total reactive fraction of trace metals relative to
total reactive-Fe (Me*) are presented in Table 6.  Normalization to total
reactive-Fe concentrations was done in order to observe if anomalously
high total reactive trace metal concentrations are present in any of
the sediments.  Such anomalies may be indicative of contamination.

(Column 2)

Trace metal chemistry of Galveston Bay

                                                                TABLE M

                         Ratios (Me*) of Total Reactive-Metal Concentration Total Reactive-Iron Concentrations
---------------------------------------------------------------------------------------------------------------------------------------

Sample	Mn*		Ni*		Cn*		Zn*		Cd*		Pb*		Cr*		Mo*		As*		Hg*

---------------------------------------------------------------------------------------------------------------------------------------

Galveston Bay
GBI-1		52.0		1.03		1.40		6.50		0.110		1.42		1.91		1.11		2.14		0.0024
GBI-2		45.3		0.80		1.63		7.17		0.222		3.74		3.73		3.16		12.48		0.0371
GBI-3		86.2		0.86		1.31		4.57		0.228		2.11		2.16		2.55		8.76		0.0019
GBI-4		60.6		0.87		1.59		6.75		0.238		2.88		2.82		3.96		16.08		0.0089
GBI-5		75.0		1.42		1.10		3.38		0.235		1.58		2.29		1.76		3.57		0.0023
GBI-6		42.6		1.13		1.62		5.36		0.381		2.49		2.62		2.05		7.97		0.0018
GBI-7		97.6		2.91		1.77		17.44		1.067		4.81		4.69		4.5		40.28		0.0026
GBI-8		56.1		2.27		1.82		7.12		0.577		3.96		7.25		4.24		7.91		0.0026
GBI-9		58.1		1.68		1.52		3.49		0.143		1.96		2.41		1.62		3.95		0.0418
GBI-10	47.1		2.13		2.39		5.76		0.287		4.04		6.24		2.57		7.40		0.0035
GBI-11	87.5		2.43		1.96		6.49		0.240		8.88		9.13		8.78		33.30		0.0061
GBI-13	47.4		2.73		1.09		3.15		0.382		1.24		1.27		0.96		1.24		0.0022
GBI-14	27.0		1.08		0.39		2.29		0.064		0.67		1.06		0.91		1.30		0.0009
GBI-16	182.1		18.28		8.64		18.64		3.330		8.36		5.87		6.21		26.11		0.0331
GBI-17	126.0		5.69		1.69		6.82		0.981		3.36		2.28		5.07		7.32		0.0032
GBI-18	126.2		6.40		1.45		6.70		0.868		5.69		4.56		8.08		145.34	0.0063
GBI-19	47.3		0.80		0.17		6.75		0.000		2.27		2.22		3.94		12.30		0.0018
GBI-20	226.0		3.26		4.42		3.72		0.461		2.37		1.38		2.21		5.15		0.0031
GBI-21	183.3		6.04		1.67		4.75		0.963		3.44		3.12		3.48		5.73		0.0067
GBI-22	69.7		1.17		0.66		4.11		0.039		1.28		1.32		1.48		3.12		0.0111
GBI-23	84.6		6.37		4.45		5.40		0.889		4.42		2.99		4.98		6.63		0.0062
GBI-24	57.9		1.01		0.93		5.32		0.105		1.75		1.96		2.01		4.11		0.0020
GBI-25	46.7		1.01		4.52		5.44		0.042		4.61		2.54		1.04		3.47		0.0068
GBI-26	45.9		1.47		3.91		7.33		0.131		1.53		5.65		1.18		7.20		0.0035
GBI-27	96.9		3.97		2.21		7.47		0.569		2.60		4.80		1.61		3.71		0.0069
GBI-28	31.5		0.89		1.00		5.38		0.059		1.08		2.20		0.63		1.36		0.0021
GBI-29	49.2		1.21		1.15		4.17		0.061		0.90		2.82		0.74		2.84		0.0017
GBI-30	45.0		1.02		0.33		3.85		0.38		1.01		1.89		1.17		4.32		0.0037
GBI-31	26.6		0.85		0.56		2.61		0.019		0.57		1.29		0.74		2.42		0.0023
GBI-32	39.1		0.91		0.83		3.07		0.028		0.74		1.57		0.52		2.12		0.0027
GBI-33	29.4		0.97		0.78		2.89		0.027		0.65		1.71		0.58		2.69		0.0056
GBI-34	31.5		0.96		0.96		3.05		0.000		0.80		1.88		0.92		2.23		0.0028
GBI-35	29.6		0.84		0.89		5.67		0.000		0.79		1.83		0.97		1.95		0.0106
GBI-36	96.9		1.02		1.07		3.64		0.072		0.84		2.04		0.78		1.65		0.0032
GBI-37	24.9		0.99		1.07		2.02		0.089		0.79		1.98		0.91		2.36		0.0023
GBI-38	24.8		1.05		5.97		6.05		0.094		1.83		2.05		3.78		7.97		0.0049
GBI-39	50.0		0.89		0.73		3.40		0.094		0.82		1.66		0.95		2.09		0.0022
GBI-40	55.0		1.02		0.52		3.85		0.065		1.16		2.01		1.12		3.67		0.0027
GBI-41	40.0		0.91		1.48		4.87		0.097		0.92		2.11		0.51		1.53		0.0020

Average	67.9		2.32		1.48		5.47		0.341		2.34		3.73		2.40		6.56		0.0065
		46.3		3.09		1.05		3.05		0.580		1.98		1.81		2.07		6.73		0.0094

Baflin Bay
86 BB2	102.9		2.97		1.93		3.59		0.128		1.32		2.62		  -		  -		   -
88 BB1	112.0		1.85		1.68		3.53		0.102		5.71		1.87		0.04		0.41		0.00244
88 BB2	 94.1		1.61		1.64		3.36		0.120		1.83		1.24		0.21		0.83		0.00461

Average	102.7		2.14		1.75		3.48		0.12		2.85		1.93		0.13		0.63		0.00362

GB/BB		0.66		1.08		0.85		1.57		2.93		0.82		1.93	     18.76	     10.45		1.80
---------------------------------------------------------------------------------------------------------------------------------------
Values exceeding twice the average are in italics.  Baflin Bay sediment data from Huerta-Diaz
& Morse (1992).  GB/BB = Galveston Bay results divided by Baflin Bay results.
Ratios are molar x 1000.

(Column 1)

22		J.W. Morse, R.J. Presely, R.J. Taylor, G. Benoit, P. Santschi

									TABLE 6B
  			Samples in Which the Value Exceeds Two Times the Standard Deviation of the Mean.
	     			Numerical Values Represent (Sample Average)/Standard Deviation
------------------------------------------------------------------------------------------------------------------------------
Sample	Mn*		Ni*		Cu*		Zn*		Cd*		Pb*		Cr*		Mo*		As*		Hg*
------------------------------------------------------------------------------------------------------------------------------

GBI-2		--		--		--		--		--		--		--		--		--		3.25
GBI-7		--		--		--		3.93		--		--		--		--		--		--
GBI-9		--		--		--		--		--		--		--		--		--		3.76
GBI-11	--		--		--		--		--		3.30		2.98		3.08		3.97		--
GBI-16	2.47		5.17		2.06		3.34		5.15		3.04		1.18		--		2.91		2.83
GBI-18	--		--		--		--		--		--		--		2.74		--		--
GBI-20	3.41		--		--		--		--		--		--		--		--
GBI-21	2.49		--		--		--		--		--		--		--		--		--
GBI-26	--		--		2.31		--		--		--		--		--		--		--
GBI-38	--		--		4.27		--		--		--		--		--		--		--
------------------------------------------------------------------------------------------------------------------------------

However, if contaminant sources introduce large quantities of iron, this
procedure might not be appropriate as an indicator of excess metals.
Observed anomalics and the relationship of metal concentrations in
Galveston Bay to other sediments will be dealt with in the Discussion
section.
	Huerta-Diaz & Morse (1990) introduced the concept of degree of trace
metal pyritization (DTMP) which is equivalent to DOP for iron.  By
comparing DTMP with DOP it is possible to relate the pyritization of a
given trace metal to that of Fe, which is the dominant metal that is pyri-
tized.  The metals can be arbitrarily divided into three major groups:
these generally exhibiting considerably less, about the same, and greater
pyritization than Fe.  Results are shown graphically in Fig. 4.  Mn, Zn, Ni,
and Pb generally fall into the first category, not being as extensively pyri-
tized as Fe.  Cu, Cr, and Mo exhibit a large scatter, but most samples fall
into the second category, being pyritized about the same as Fe.  Arsenic
and Hg are often much more extensively pyritized than Fe.  The concen-
trations of Cd were often close to or below detection limits and such a
relationship is not reliable for this metal.

					DISCUSSION

To our knowledge these are the first reliable, systematic measurements of
trace metal concentrations other than As and Sb in the water column of
Galveston Bay.  Data bases of the Texas Water Commission (TWC),
Army Corps of Engineers, and US Geological Survey contain many

(Column 2)

Trace metal chemistry of Galveston Bay					23

(3 Graphs, ABC)

Fig. 4.  The relationship between trace metal (DTMP) and iron (DOP) pyritization,
(A) Metals generally undergoing less pyritization than Fe (white square = Mn; black
square = Sn; white triangle = Pb; black triangle = Ni). (B) Metals generally having
a similar degree of pyritization to that of Fe (+ = Cu; x = Mo; black diamond
= Cr). (C) Metals generally undergoing greater pyritization than Fe (white circle =
As; black circle = Hg). Dashed lined is for 1 to 1 ratio of DTMP to DOP.

24	 J.W. Morse. R.J. Presley, R.J. Taylor, G. Benoit, P. Santsclu
														Trace metal chemistry of Galveston Bay  25

years of trace metal data from surface water, but these measturemtns	  	  In Fig. 3 the concentrations of metal on suspended particles vary over
are invalid due to sample contamination and/or insufficient analytical		a range that brackets the average values in surface sediments.  This is ex-
sensitivity.  Our values are typically 100 to 1000 times lover than the ear-  actly what would be expected if metals on the suspended particles were
lier analyses.  The difference most probably reflects our more careful mea-   derived directly from resuspended bottom sediments.  The range in con-
surements rather than any real change in metal concentrations over time.      centrations in the water column can be explained by the range in concen-
  Galveston Bay is very shallow, so SPM levels, and their trace metal 		tration on bottom sediments, but this is probably modulated by the
burdens, should be dominated by resuspension and settling of bottom		preference of metal for fine sediments and differntial resuspension and
sediments.  Because of this close coupling between the water and sediment	settling of different sediment size classes.  In particular, under conditions
colums, it seems likely that particulate metals in the water column will	of low wind stress and turbulence, SPM concentrations are lower and are
reflect levels in surficial bottom sediments.  Supporting this expectation.	probably composed largely of finer sediments, which are enriched in
particulate metal concentrations broadly mirror SPM levels, with Zn and 	trace metals.  COnversely, stronger winds resuspend a greater number of
Pb showing mid-salinity maxima in August, and corresponding minima		larger particles, which are comparatively depleted in metals.  Figure 3
in Octor.  Figure 5 shows the good corrclation between particulate Zn		shows that trace metals concentrations on suspended particles do, in fact,
and Pb concentrations with SPM concentrations for October samples.		decrease with increasing SPM concentration for all four metals.  This is
The linear corrclation is remarkable. since it implies a nearly constant	consistent with previous observations by DUinker (1983) who associated
concentration of these two metals in bottom sediments across the entire		this inverse correlation to the fact that high levels of SPM include a sub-
estuary.  The slopes of the two lines give average concentrations (Zn 4I	stantial fraction of heavier, larger-sized particles and aggregates, origi-
pg kg . Pb--12 pg kg').  The other data show weaker correlations,			nating from resuspension of surface sediments.  Larger particles are often
perhaps because metal concentrations in surficial bottom sediments		mainly composed of quartz-grains which have a lower trace metal con-
ordinarily exhibit a wide range. rather than a uniform value.			centration thus diluting the pool of line suspended particles enriched in
													organic carbon and metal oxides, the most efficient carrier phases for
													many trace metals.  Alternatively, this behavior can also be produced by
													the particle-concentration effect, which has as a cause the presence of
													trace metal-containing colloidal particles in the filter-passing fraction
													(Honeyman & Santschi, 1989: Baskaran & Santschi, 1992: Baskaran
													et al., 1992).  One way to test this hypothesis would be to measure
													particulate trace metal levels as a function of suspended particle size,
													including colloidal particles.
													  Dissolved trace metals do not show a simple pattern relative to salinity
													or SPM concentration (not shown).  Based on our research unsing
													naturally occurring radionuclides (Baskaran & Santschi, 1992; Baskaran
													et al., 1992), we believe that trace metals are scavenged and released very
													rapidly in Galveston Bay waters.  This means that dissolved trace metal
													levels are the result of rapid particle uptake (adsorption and colloid
													aggregation) and release from particles (desorption and colloid disaggre-
													gation). as well as rapid cycling of particles derived by resuspension of 
													bottom sediments through the water column.  Thus, dissolved trace metal
													levels are controlled mainly by the combination of three processes: (1) re
													suspension of bottom sediments to yield particulate and colloidal metals,
													(2) steady-state equilibrium partitioning of metals between solid and
													liquid phases, (3) steady-state partitioning between particles of different
													sizes including those in the colloidal size range.  As a result, dissolved



Fig. 5.  Filter-retained Pb and Zn concentration in the water column as a function of 
SPM.  The good corrclations support the hypothesis that particulate metals in the water
column are derived from resuspended bottom sediments.  The linear relationship implies
that the suspended sediments have nearly a constant metal conccutration (pg g') at all
					    locations sampled.	

 

26 J. W. Morse, R. J. Presley, R. J. Taylor, G. Benoit, P. Santschi
trace metal levels should depend on bothe the quantity and size spectrum of suspended particles, and on their partitioning characteristics. Further  research is needed to elusidate the details of such a relationship.
although the behaviour of the dissolved metals was complex, certain simple trends are worth noting. In general, metal concentrations were lowest near the fulf salinity end member. this is to be expected, since rivers act as a source of metals to the ocean. Also, at all salinities, dissolved Pb was much lower than particulate Pb, while the opposite was true for Cu. Zinc and Ag showed approximately equal partitioning between dissolved and particulate fractions. This trend matches our expectations ince Pb is highly particle reactive (e. g. Balistrieri & Murray, 1984: Santschi el al., 1984), while Cu tends to form soluble organic com-
8000
1986
1987
6000
1988
1989
1990
4000
2000
0
GBR GBHR GBOB GBSC GBID GBYC
Zinc (ppm)
10
8
6
4
2
0
GBCR GBHR GBOB GBSC GBID GBYC
Cadmium (ppm)
Fig. 6. annual mean and standard deviation of metal concentrations in oysters collected at six sites in Galveston Bay from 1986 90. Solid horizontal line represents mean of 874 oyster samples collected alon US Gulf of Mexico coast from 1986 to 1990. (A) An. (B) CJ.
Trace metal chemisty of Galveston Bay		27
plexes (e. g. Sunda & Hanson, 1987). dissolved Cu showed the simplest pattern against salinity, decreasing from the fresh to the saline end member via a mid-salinity maximum. this pattern would be consistent with release of dissolved Cu from particles or sediments at mid-salinities. Another possibility is addition of dissolved Cu in water originating from the San Jacinto River or Clear Lake area.
Trace metal concentrations in various estuaries exhibit a wide range, reflecting large local differences in inputs and removal processes. For that reason, it is difficult to compare Galveston Bay to other estuaries, except to say that concentrations are in the same range as measurements elsewbere. Since, unfortunately, these are the first reliable trace metal data for this estuary it is impossible to draw conclusions about historical trends. Because metals in Galveston Bay waters are dominated by exchange with sediments, it seems reasonable that water column metal concentrations are as variable as sediment metal concentrations (see below).
Discussion of metals in Galveston Bay oysters averaged over all sites and all years obviously cannot show possible geographic and temporal trends within the Bay. In the case of Zn, for example, it can be seen (Fig. 6) that three of the six Galveston Bay sites had oysters with near Gulf average Zn, with relatively little year to year variations. The other three sites, two of which were not sampled in the first two years of the program, had much higher Zn concentrations. Two of the sites with high Zn concentratiosn, Ship Channel and Yacht Club, are in northwestern Galveston Bay near industrial waste water inputs and boat basins where Za contamination might be expected.
The other site with high Zn concentrations was in Offatts Bayou on Galveston Island and is surrounded by residential development and private boat moorings. This site was moved a few hundred metres between year three and year four, and the Zn concentration in oysters was lower by about 50%. This shows the extremely local influence on Zn content of oysters. Local control can be seen even more dramatically in the variations between stations at a given site for a given year (data not given here). Local control on Zn, and on other metals is seen not only in Galveston Bay but also throughout the Gulf of Mexico. For example, oysters from one site in Tampa BAy averaged 200-300 mgg Zn over the first five years of NS&T while a nearby site averaged 6000-8000 mgg (GERG, 1990). On a temporal scale, particularly large changes in Zn were found in Sabine Lake, Texas, another industrialized site. It seems likely that the big changes in Zn from time to time and place to place are caused by human activities, but the exact activity responsible for such a pattern has not been identified. Alternatively, it could be caused by  


28                 J.W. Morse, R.J. Presley, R.J. Taylor, G. Benoit, P. Santschi                                      Trace metal chemistry of Galveston Bay         29


natural variations in concentrations and chemical form of sedimentary Fe, as suggested by Luoma & Bryan (1978).
Cadmium, Pb, Ag and Hg are often added to the environment in industrial areas by human activities in amounts rivalling those added by natural processes (e.g. Bowen, 1979; Fergusson, 1990) but there is little evidence of anthropogenic inputs of these metals in the Galveston Bay oyster data, except possibly for Pb. Confederate Reef and especially Hanna Reef are in open areas of the Bay, well away from industrial activity, yet oysters from these reefs are similar in Cd, Ag and Hg content to those from reefs along the highly industrialized northwestern shore of the Bay and are only slightly lower in Pb. The Cd pattern (Fig. 6) is thus representative of the distribution of these four toxic materials. Note that the highest Hg value found was at Hanna Reef, apparently the most pristine site sampled. Furthermore, the most anomalous Ag value was found at pristine Confederate Reef where all three stations sampled in 1990 were extremely enriched in Ag. We have no explanation for these results.
Attempting to assess whether sediments in a region such as Galveston Bay are contaminated with respect to a given metal is difficult. Much of this difficulty arises from the heterogenous nature of the sediments. For many of the metals under consideration the variation in grain-size distribution can easily lead to variations of a factor of two or more in absolute metal concentrations (Table 4). Consequently, simply giving average total concentrations can be quite misleading, if it is not normalized to grain size (Table 4).
Secondly, in order for contamination to cause a major change in average concentrations, over the entire estuarine system, large amounts of the metal from anthropogenic sources would have to be added (e.g. for Cu which is of intermediate concentration for the trace metals studied, about 60 mg m year of Cu, equivalent to 80 tons year for all of Galveston Bay, would have to be added to the sediments to double their average Cu concentration. This extimate assumes 13 mgg Cu interface sediments,and a sediment delivery rate to the Bay of 6 X 10 tons year (GURC. 1965). Thus, unless truly massive contamination with a given metal occurs it is generally not possible to detect the enrichment against the background of natural variability using regional averages.
However, while it is difficult to asses whether or not an entire area may be contaminated with a given metal, it is frequently possible to identify local sub-areas that have anomalously high concentrations of a given metal relative to the region under study as a whole. Such areas haveoften been observed to be close to the source of anthropogenic metal inputs. It must be kept in mind aht formation of such 'pockets of contamination' is strongly dependent on the degree of dispersion of the introduced metal, and a variety of other processes such as biological uptake and sedimentation patterns.
As discussed in the Results section, in this sutdy the search for sediments with anomalous metal concentrations was undertaken by ratioingtotal reactive-metal concentrations to total reactive-Fe is designated Me*. Average values of this parameter in Galveston Bay are compared to equivalent values in Baflin Bay, Texas (Huerta-Diaz & Morse, 1992) in Table 6. Baflin Bay was chosen for comparison because it is remote from major population centres and similar data exist for sediments from this Bay. (It should be noted that Baflin Bay is generally hypersaline whereas Galveston Bay has a salinity less than that of seawater.) Mn* is less inGalveston Bay, and Ni*, Cu*, and Pb* are similar in both bays. Zn*, CD*, Cr*, and Hg* ar at least 1-5 times higher in Galveston Bay. Mo* and As* are at least an order of magnitude higher in Galveston Bay than Baflin bay, but total As and other metals in the sediments of Galveston Bay are similar to concentrations in other Texas and Louisiana bays (GERG,1990). 
It is not possible to unambiguously ascertain whether the trace metals that are higher in Galveston Bay are so as a result of anthropogenic inputs or differing natural sources and processes in the two bays. For example, Mo and As, which are highly elevated in Galveston Bay sediments relative to Falin Bay, exist in the water column dominantly as molybdate and arsenate, and As has been observed to be at close to normal concentrations in the open water column (Tripp, 1988). In the sediments they are extensively reduced along with sulphate and incorporated into iron sulphide minerals. The salinity in Baflin Bay is typically about four times higher than in jGalveston Bay. Consequently, even if Mo and As were in similar concentrations in the water column, their ratio relative to sulphate would be about four times higher in Galveston Bay. This difference in ratios could then well be reflected in their incorporation into sediments.
Three approaches have been made to try to identify sites in Galveston jBay which have 'anomalous' metal concentrations using Me* values. The first two are given in Table 6A, where samples having twice the average value are given in italics, and Table 6B where samples having a difference of over two standard deviations from the average value are given. The third approach is non-statistical and consists of observing Me* values in histograms (Fig. 7). The choice of values above which Me* is considered 'anomalous' is arbitrary. For some metals, such as Zn, it is relatively obvious, for others, such as Cr it is difficult. The histograms in Fig. 7 are

                                           

    






                               30            J W Morse, R. J. Presir"I., ft. J. TaYlor, G. Benoic 1@ Sanfvchi                                                                      Trace tPietal chentistry of Galveston Bay                               31

                                                                                                                                                                                                                        is
                                                                                                                                                                                      Nickel*                                               Mercury*
                                                                                                                                                           V)   12                                                      15                   (X 1000)
                                                                                                                                                                                                                    ILL 12
                                                                                                                                                                                                                    E
                                      15                                                            25                                                     E    9
                                                                                                                                                           13
                                                            Zinc*                                                      Cadmium*                            !n                                                       'B
                                 01   12                                                            20
                                                                                                                                                           E                                                        E
                                 10                                                                                                                        -3   3                                                   7)
                                                                                                                                                           z                                                        z
                                                                                              T                                                                            .12MMI                                   1 :@          -m-lawk
                                                                                              2     10                                                          0                                                       0 02 2.4    46    60 8,10 10
                                 do                                                           W
                                                                                              KI
                                 E



                                      0     24 40 60 8.10 10                                        O@O 2 0 2 OA 0 4 0.6 0.6 O's 0.0.1 1                        15                                                      15
                                                                                                                                                                                  Molybdenum*                                            Chromium*
                                                                                                                                                                12                                                      12


                                                                                                                                                                9                                                   E   9
                                                        Manganese*
                                                                                                    10                  Copper*
                                 0    12                                                                                                                        6
                                 T                                                        0

                                                                                                                                                                                                                        3
                                      9
                                      6                                                             6                                                           01                                                      0 --                B14
                                                                                                                                                                 Ol 12 ZI 3,4 45 56 6                                     01 12 23 34 45 56 .6

                                 E
                                      3                                                  E                                                                                                        Fig. 7.    conlit
                                      01                                                            Oil
                                      'j
                                         'V JP AV
                                                                                                                                                       arranged in increasing order               of difficulty in making such a judgement.
                                                                                                                                                       The values chosen arc Zn* > 10, Cd* > 0.8, Mn* > 120, Cu* > 3.5,
                                      15                                                            12                                                 As* > 12, Pb* > 3. Ni* > 3, I-lg* > 0-01, Mo* > 6, and Cr* > 6.
                                 M    12                   Arsenic*                                 10                    Lead*                            Almost half (17 out of 39) sites exhibited an anomalous value for at
                                 2                                                            0                                                        least one metal by a( least one of the above criteria (Table 6B). Site GBI-
                                 CL                                                           W
                                 E                                                            LL    8
                                      2                                                                                                                16 off Eagle Point had anomalous value,.; for all metals. The number of
                                                                                                                                                       sites having anomalous values for each metal is Pb = 9, Ni                                7, Cd and
                                 0
                                                                                                                                                       As = 6, Mn and Mo = 5. Cr and fig = 4, Cu = 3. and Zn                                      2. Exccp-
                                                                                                    4
                                 E                                                                                                                     tionally higher values (delined its -4 times higher the standard deviation
                                                                                              E
                                                                                              z                                                        above the average) were encountered for Ni* and Cd* a( site Gill-16,
                                                                                                    2L                                                                   -38, Zn* at site 6131-7, and As* at site G111-1 1. While the
                                      0 2 2.4 4.6 G-a 6 tO 10A2 .12                                 a0-05 0.5-1 1-1.5 15 222.5 2.53 13                 Cu* at Gill                                                                                    I
                                                                                                                                                       high Cu* (Clear Lake site) may possibly be explained by leaching of Cu
                                                                                                                                                       froin anti-fouling paints on the many boats moored in this small area, the
                                                                                                                                                       possible reasons for the other high values are not obvious. It is interest-
                                                                                                                                                       ing to note that few of' the exceptionally high values occurred near Texas
                                          L




                                                                                                                                                       City or directly in the Houston Ship Channel, where higher contaminant
                              Fig. 7. tlistograms of Mle* (= reac(ive-mcial to reaciive-iron concentralion ratio) values                               metal concen t rations might be expected, but that about 6(YY,. of the
                                                     for different metals in Galivesion flay sedimenis,                                                dredge spoil sites had anomalous metal coriccritrations.


32             J.W. Morse, R.J. Presley, R.J. Taylor, G.Benoit, P. Santschi                              Trace metal Chemistry of Galveston Bay                                     33
                                                                                                               SUMMARY AND CONCLUSIONS
  100

   80

   60

   40

   20

    0  Zn  Mn  Mi  Pb  Cd  Cr  Cu  Mo  As  Hg

Fig 8. Histogram of percentage of samples for different metals having greater than 20% of the total reactive fraction pyritized in the top 10 cm of sediment.

A major objective of thsi investigation of trace metal levels in sediments was to investigate if extensive pyritization of reactive trace metal takes place near the sediment water interface (approximately top 10cm In the Results section data were presented indicating that this does occur for several of the metals of interest. Figure 8 is a histogram giving the percentage of each metal that was significantly (here defined as >20% pytitized. Metals in which less than 15% of the samples fell in this catagory include Zn, Mn, Ni, and Pb. As previously discussed, the data for Cd are uncertain due to its low concentration. Over 75% of the Cr, Cu, Mo, As and Hg samples were significantly pyritized. It should be noted that previous studies (e.g. Huerta-Diaz & Morse, 1992) indicate that pyritization of metals dominantly occurs in the upper 10 cm of sediment in fine-grained sediments associated with coastal environments. Consequently, these observations are of likely general validity for Galveston Bay. It is also interesting to note that the most extensively pyritize metals, As and Mo, both have total reactive concentrations normalize to Fe over an order of magnitude higher than in Baflin Bay sediments.
Based on extensive investigations into concentrations and chemical forms of selected trace metals in water, sediments and biota (e.g. oysters), we come to the following conclusions:
(1)Trace metal concentrations in the open water column of Galveston Bay are similar to those in apparently more pristine bays nad estuaries. Cu, Zn, Pb, and Ag concentrations in the water column of Galveston Bay are low, and are mostly regulated by sediment dynamics (wind and tide generated sediment suspension and settling), leading to significant association with SPM and correlations of their particulate concentrations in the water with suspended matter concentrations. Concentrations of these metals in suspended particles >0-4mm, diameter resemble those inthe sediments and are higher at low particle concentrations, indicating enrichment in the finer, slower settling fraction.
(2)Except in Zn, trace metal conceantrations in oysters from Galveston Bay are similar to those in oysters from pristine areas elsewhere and do not reflect the relative differences inproximity to population and industrialization centres of the different sampling sites in the Bay.
(3) Average trace metal concentrations in the sedimnets are similar to those from other estuaries. However, due to the large range of concentrations observed for many trace metals, meaningful comparisons require normalization to grain size and reactive-Fe. In Galveston Bay sediments, total reactive Zn, Cd, Cr, and Hg are at least 1-5 times higher, and As and Mo over an order of magnitude higher when normalized to reactive-Fe, than in sediments from Baflin jBay (Huerta-Diaz & Morse, 1992). Since trace metals in the water column closely reflect those in sediments of this estuary, it is likely that the same metals may have been historically elevated in teh water column as well. Forty four percent of the individual sites in jGalveston Bay exhibit and 'anomalous; concentration with respect to at least one of the metals studied. About half of these sites were directly associated with dredge spoils. It is not possible to unequivacally determine if this is the result of contamination from anthropogenic sources, however, it is probable that these elevated concentrations of metals in the sediment reflect past conditions during which anthropogenic metal inputs were higher.
(4) A major fraction of reactive Cr, Cu, Mo, As, and Hg are immoblized by incorporation into authigenic pyrite in the top 10 cm of sediment. These metals may be transformed via pyrite oxidation (Morse, 1991) to more bioavailable species if the sediments are resuspended in teh oxic water column by storms or activities such as dredging and bottom trawling.    

34      J. W. Morse, R. J. Presley, R. J. Taylor, G. Benoit, P. Santschi

ACKNOWLEDGEMENTS

The authors were supported in this research by the NOAA Sea Grant Program (J.W.M.), NOAA Status and Trents Program (B.J.P.
and R.J.T.), the Texas Chemical Council and the Texas Institute of Oceanography (P.S. and G.B.).
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36		J.W. MORSE, R.J. PRESLEY. R.J TAYLOR, G. BENOIT, P. SANTSCHI

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	randum NOS OMA 49.  NOAA office of Oceanography and Marine
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	appendix.
Patterson, C.C.& Settle, D.M. (1976). The reduction in order of magnitude
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Presley, B.J., Taylor. R.J. & Boothe. P.N. (1990). Trace metals in Gulf of
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	concentration of trace elements from seawater with sifica-immobilized
	8-hydroxyquinoline.  Anal. Chem., 53,2337-40.
Sugimura, Y. & Suzuki, Y. (1988). A high-temperature catalytic oxidation
	method for the determination of non-volatile dissolved organic carbon in
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Sunda, W.G. & Hanson, A.K. (1987). Measurement of free cupric ion concen-
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				Trace metal chemistry of Galveston Bay    37
Windom & R.A. Duce. D.C. Heath and Company, Lexington, MA,
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                          Reprint 8

              Mercury Bioaccumulation by Shrimp
               (Penaeus aztecus) Transplanted to
                      Lavaca Bay, Texas


              Sally J. Palmer and Bobby J. Presley


















                              1-81


								Marine Pollution Bulletin

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Marine Pollution Bullene., Volume 26. No. 10.pp. 562-566.1993.				(4)25-326x '93 s6.00-0.00
Printed in Great Britain.										O 1993 Pergamon Press Ltd.

	

Mercury Bioaccumulation by Shrimp
(Penaeus aztecus) Transplanted to 
Lavaca Bay, Texas

SALLY JO PALMER and BOBBY JOE PRESLEY
Department of Oceanography, Texas A&M University, College Station. TX 77843. USA


A field study was conducted to determine mercury
accumulation rates by brown shrimp.  Penaeus aztecus,
transferred to a mercury contaminated estuary, Lavaca
Bay, Texas.  Mercury levels in the caged shrimp rose 
from an average baseline value of 347 163 ppb to
1170 107 ppb in 36 days, resulting in an average rate
of mercury uptake of 22 ppb per day.  Our results show
that shrimp rapidly accumulate Hg when confined to a 
contaminated area, even though the natural population
of shrimp in Lavaca Bay is not conataminated

As much as 29.9 kg day -1 of mercury was released into
Lavaca Bay, Texas from 1966 to 1970 by waste water
from a chlor-alkali plant (Fig. 1).  Since 1970 the Texas
Department of Health (TDH) has issued periodic
health warnings and bay closures due to elevated (>0.5
pm wet wt) Hg levels in Lavaca Bay organisms, only to 
reopen the bay to fishing when the Hg levels decreased.
Portions of the bay closed to commercial and sport
fishing of finfish and crabs in 1988 have not been
reopened as of this writing.  Unlike natural population
of oysters (Crassostrea virginica) and blue crabs
(Callenectes sapidus) in Lavaca Bay no high (>0.5 ppm
wet wt) mercury levels in shrimp have been reported
by the TDH (Trebatoski & Gooris. 1990) or other
researchers who worked in the area (Blanton & 
Blanton. 1972: Palmer. 1992).  Therefore all of Lavaca
Bay remains open to shrimping.

Numerous laboratory metal accumullation studies
have been conducted using a variety of invertebrates
over the years (e.g. King & Davis. 1987: Riisgard &
Famme. 1986: Zanders & Rojas. 1992).  In the work 
reported here instead of a laboratory study, field caging
experiments were used to determine the uptake rate of 
mercury by shrimp confined to a contaminated area of
Lavaca Bay.  To our knowledge.  this is the first time that
transplanted shrimp have been used to determine
mercury accumulation rates in the field.  Although it is
impossible to control variables such as temperature, 
salinity, food supply and turbidity in a field study, the
authors felt that a field caging study woult better reflect
natural conditions than a laboratory study using Lavaca
Bay sediment of mercury contaminated food.

Materials and Methods

In July 1991 similarly sized (3.2 0.31 cm rostral
length: 3.16 0.31 g wet wt) adult brown shrimp
(penaeus aztecus) were collected from Matagorda Bay
in a relatively uncontaminated area about 10 km from



564						1-83


Fig. 2 Mercury concentrations is shrimp from Matagorda Bay
confined to Lavaca and keller Bays.  Each symbol represents an
individual shrimp sacrificed on that day. Lines are best fit 
through all data from each bay.

which feed on shrimp. were a prime interest in this
study, therefore, the shrimp were analysed whole. Once
thawed, the shrimp were rinsed, weighed, freeze dried, 
and digested according to a modification of USEPA
method 245.1 (USEPA. 1990) All samples were 
analysed in replicate for total mercury using cold
vapour atomic absorption spectrophotometry (Hatch & 
Ott. 1968).

Data quality control
   Included with each set of samples analysed were
blanks and a dogfish muscle reference material.
DORM-1. certified for Hg by the National Research
Council of Canada.  Analyses of DORM-1 run with
each set of shrimp samples were within the certified
value for Hg 95% of the time.

Statistical analysis
   To determine relation ships between total Hg. caging 
sites and time, statistical analyses using SAS Institute
Inc. software (SAS Institute Inc. 1985) were performed.
The general linear model (GLM) was used to test for
significant differences in Hg levels between Lavaca and
Keller Byas and day of the caging experiment.  The
Least Square Means test. LSMEANS. was used to 
verify changes in shrimp Hg levels over the duration of
the experiment.

Results

    Slightly, Hg contaminated Matagorda Bay shrimp 
caged in the highly contaminated portion of Lavaca Bay
readily accumulated additional Hg While shrimp caged
in uncontaminated Keller Bay did not sighificantly
change in Hg concentrations during the 36 day
experiment (Fig 2) Average Hg concentrations in
shrimp caged in lavaca Bay climbed from 347+163
ppb dry wt (n=9) on day 0 to 1170+107 ppb (n=3)
on day 36 Using the shrimp baseline and final mercury
concentrations, the average daily rate of Hg uptake was
22 ppb over the36 day experiment.
     The LSMEANS test showed that Hg levels in shrimp
caged in Lavaca Bay on day 22 were significantly
higher (p<0.05) than baseline concentrations.  The 
GLM procedure indicated a significant difference in Hg
concentrations between Lavaca and Keller Bays at 
every sampling period after day 0 at the p<0.05 level.
                                                   
                       

Fig. 1 Map of Lavaca Bay area showing the Matagorda Bay shrimp
collection site and the caging sites in Lavaca and Keller Bays.

the most heavily Hg contaminated part of Lavaca Bay.
These were transferred to the caging experiment sites in
Lavaca Bay and the control site, Keller Bay (Fig. 1).
The cages, 20X20X20 cm plastic storage crates, were
lined with 3.3 mm plastic mesh and held tow shrimp
each.  To facilitate handling, groups of eight crates were
attached to 0.5X1.0 m plastic grates. Individual cages
were spaced approximately 7 cm apart on the grates to 
minimize restriction of water flow around them.  At each
site the three grates holding the cages were tied
together, weighted and pushed at least 1 cm into the
sediment.  Therefore the caged shrimp could derive
food from organic detritus in the bottom sediment
(Britton & Morton 1989) as well as plankton and
demersal fauna that entered the cage through the mesh
(Gleason & Wellington. 1988).
    The caged shrimp were sampled six times over a
period of 36 days.  At each sampling as many as nine
individuals were collected from each of the two
locations.  Immediately after collection the animals were
placed in plastic bags and frozen until analysed.  The 
cages that remained in the field after each sampling
episode were shifted slightly within the site in hopes of
renewing the food supply, but it is nevertheless possible
that the shrimp suffered food depravation.  Although the
average dry weight of the whole shrimp decreased over
the experimental period from 1.25+0.39 g (n=9) to
0.97+0.09 g (n=6) in Lavaca Bay and 0.71+0.11 g
(n=7) in Keller Bay, the shrimp were vigorous and 
appeared to be healthy when sampled.
    Food chain relationships, especially potential routes 
of Hg transfer to large commercially important finfish
                                                       565


                               1-84




                                                                                                                                                   Marine Pollution Bulletin

                      Discussion and Conclusions                                                     showed that average Hg levels in abdominal tissue were
                                                                                                     2.25 times greater than in head and exoskeleton. There-
                          The accumulation of mercury by shrimp confined to                          fore it is likely that the edible muscle tissue of the
                      a contaminated area of Lavaca Bay shows that shrimp                            shrimp caged in Lavaca Bay became more con-
                      can become contaminated with Hg if forced to remain                            taminated during the 36 day exposure period than did
                      in a contaminated area for three weeks or more. The                            the whole organism.
                      fact that the natural population of shrimp collected in
                      the contaminated area are not contaminated implies                                 The observation that the natural population of
                                                                                                     shrimp caught from Lavaca Bay are not contaminated
                      that they spend less than three weeks at a time in this                        with mercury suggests that shrimp spend much of their
                      area. Additionally, the caging experiment in Keller Bay
                                                                                                     time and obtain much of their food in non-contamina-
                      suggests that slightly contaminated shrimp are slow to                        ted areas of the bay or coastal ocean. The relative
                      depurate Hg. This contrasts with results from a similar
                                                                                                  importance of water. sediment. and food in the accumu-
                      experiment where contaminated oysters rapidly                          lation of Hg by shrimp is still poorly understood and
                      depurated Hg when placed in Keller Bay (Palmer et al.,                         could not be resolved in this study because all three
                      1993). The slow depuration of Hg by shrimp and the
                                                                                                     media are known to be enriched in Hg at the caging site
                      low Hg in the natural population of shrimp in con-                             near the old chlor-alkali plant (Palmer. 1992).                            taminated Lavaca Bay implies that the shrimp do not
                      move into and out of the contaminated area on a time                           Blanton. W. G. & Blanton. C. J. (1972). Final report: a study of the
                      cycle that would result in their spending more than a                          concentrations of mercury in tissues of selected animals from Lavaca
                                                                                                     Bay, Texas.  The Texas Water Quality board. Austin. Texas
                      total of three weeks in the contaminated area during                           Britton. J.C. & Morton. B (1989). Shore Ecology of the gulf of mexico.
                      their lifetime.                                                                 University of Texas Press.
                          The difference in Hg loss rates between oysters and                        Gleason. D.F. & Wellington, G. T (1988). Food resources of postlarval
                                                                                                      brown shrimp (Penaeus aztecus) in a Texas salt marsh. Mar. Biol. 97.
                      shrimp may be due to differences in Hg speciation                               329-337.
                      within the organisms, but we have no data to  document                        Hatch. W. R. & Ott. W.L. (1968). determination of sub-microgram
                      this, Riisgard & Famme (1986) for example    found the            quantities of mercury by atomic absorption spectrophotometry.
                                                                                                      Anal.Chem. 40.2085-2087.
                      retention efficiency. defined as the amount of accumu-                         King. D.G. & Davies. J.M. (1987). Laboratory and field studies of the
                      lated mercury divided by the amount of ingested                                 accumulation of inorganic mercury by the mussel Mytilus edulis (L.)
                      mercury, in shrimp. Crangon crangon. to be 4% for                                Mar. Polha.Bull. 18,40-45.
                                                                                                   Palmer. S J.(1992). Mercury bioaccumulation in Lavaca Bay. Texas.
                      inorganic and 75% for organic mercury during their 28                              Thesis. College Station. Texas.
                      day experiment. It is well known that methyl mercury                           Palmer. S.J.,Presley. B. J. Taylor. R. J. & Powell. E.N. (1993).Field
                      is more efficiently accumulated and retained than                                studies using the oyster Crassostrea virginica to determine mercury
                                                                                                      accumulation and depuration rates. Bull.Environ. Contamin.
                      inorganic mercury (Riisgard et al.. 1985). Shrimp.                           Toxicol (in press).
                      unlike oysters consume sediment dwelling organisms.                              Riisgard. H.U.& Famme. P, (1986). Accumulation of inorganic and
                      These may contain a higher proportion of methyl                                  organic mercury in  shrimp. Crangon crangon. Mar. Pollut. Bull. 17.
                      mercury than plankton and organic detritus found in                            Riisgard.H.U. Kjorbe.T., Mohlenberg. F.,  Drabaek I.& Pheiffer
                      the water column. even though our data of total Hg                               Madsen. P.(1985). Accumulation. elimination and chemical
                      shows these two food sources to be similarly con-                                 speciation of mercury in the bivalves Mytilus edulis and Macoma
                      taminated (Palmer. 1991).                                                         balthica Biol. 86.55-62.
                                                                                                     SAS Institute Inc. (1985) SAS' User's Guide: Statistics. Version 5
                          Since an aliquot of a whole homogenized shrimp was                             Edition. SAS Institute Inc.
                      used for analysis in this study. concentrations in Muscle                        Trebaloski.B. & Gooris. J. (1990). Texas Water Commission Natural
                                                                                                      Resource Damage Assessment: Pre-assessment Screening
                      tissue cannot be obtained directly from this data.
                                                                                                      Document of Lavaca Bay 2453. (Corpus Christi. Texas).
                      However. in a separate study  (Palmer. 1992), 18                                USEPA (1990). Contract Laboratory Program Statement of Work for
                      Matagorda Bay shrimp collected with those used in the                           Inorganics Analysis  document Number ILMO1.0.
                                                                                                     Zanders. P I. & Rojas. W. E. (1982). Cadmium accumulation. LC, and
                      caging    accumulation studv were dissected into muscle                         0xygen. consumption in the tropical marine amphipod Elasmopus
                                                                                                       rapax. Mar. Biol. 113.409-413.
                      (abdominal tissue). exoskelton. and head. The results                            



















                      566
                                                                                                     1-85


















                          Reprint 9

              Pol nuclear Aromatic Hydrocarbon
           Contaminants in Oysters from the Gulf of
                     Mexico (1986-1990)


              Thomas J. Jackson, Terry L. Wade,
            Thomas J. McDonald, Dan L. Wilkinson
                     and James M. Brooks




















                             1-87






         Environmental Pollution 83 (1994) 291-298




                           POLYNUCLEAR AROMATIC HYDROCARBON
                               CONTAMINANTS IN OYSTERS FROM THE
                                             GULF OF MEXICO (1986-1990)


                      Thomas J. Jackson, Terry L. Wade, Thomas J. McDonald, Dan L. Wilkinson
                                                                & James M. Brooks
                            Geochemical and Environmental Research Group, College of Geosciences and Maritime Studies,
                                              Texas A & M University  College Station. Texas 77845. USA

                                                  (Received I July 1992: accepted 25 September 1992)

         Abstract                                                                equilibrium concentration for trace organic contami-
         Polynuclear aromatic hYdrocarbon (PAH) contaminant                     nants such as PAHs within approximately one month
         concentrations in 870 composite oYster samples from           (Sericano & Wade. unpublished data).
         coastal and estuarine areas of the Gulf of Mexico ana-                     To assess the spatial and temporal variation of con-
         lyzed as part of National Oceanographic and Atmo-                       taminant levels of coastal and estuarine environments.
         spheric Administrations(NOAA's) National Status and                   the National Oceanic and Atmospheric Administration
         Trends (NS& T) Mussel Watch Program exhibit a log-                     (NOAA) instituted the National Status and Trends
         normal distribution. There are two major populations in                 (NS&T) Mussel Watch Program under its Program for
         the data. The cumulative freuency function was used to            Marine Environmental Quality (O'Connor. 1990). The
         deconvolute the data distribution' into two probabilitY                 sample sites were selected to characterize the overall
         densitY functions and calculate summarY statistics for                  concentration of contaminants in coastal and estuarine
         each population. The first population consists of sites                 ecosystems away from known point-sources of contam-
         with lower PAH concentration probably due to back-                        ination.
         ground contamination  i.e. stormwater runoff, atmo-              The focus of this paper is to examine the distribution
         spheric deposition;. The second population are sites with             of the PAH contaminant concentrations in oysters
         higher concentrations of PAHs associated with local                    collected from the Gulf of Mexico as part of NOAA's
         point sources of PAH input ,i.e. small oil spills, etc.      NS&T Mussel Watch Program. and determine the
         The temporal pattern for the mean concentration of the                  environmental factors controlling, the concentration of
         populations from the Gulf of Mexico is consistent with                 PAHs.
         large-scale climatic factors such as the El Nino cycles
         which affect the precipitation regime.
                                                                                 METHODS
         INTRODUCTION                                                            Sample collection
                                                                                 Oysters (Crassostrea virginica) were collected from
         Oysters and other bivalve molluscs have been used for                   three stations at each site durine the winter of each
         monitoring contaminants in the environment (Farring-                    year (1986-1990). The number of sites per year varied
         ton et al 1983). Oysters are sentinel organisms which                   from 48 to 68. In some years not all sites had three
         concentrate contaminants from the marine environ-                       stations due to the low abundance of oysters at a specific
         ment. yet do not readily metabolize contaminants such                   site (Table 1). Sample sites give coverage of the Gulf of
         as polynuclear aromatic hydrocarbons (PAHs) (Far-                       Mexico coastal and estuarine areas from southern-most
         rinton & Quinn, 1973). PAHs enter the near-coastal                     Texas to southern-most Florida (Fig. 1). Individual
         environment through a number of mechanisms (e.g.                        stations at each site are generally from 100 to 1000 m
         runoff. discharge of industrial waste or sewage. natural               apart. An analysis at each station represents a corn-
         or industrial combustion processes. natural oil seep-                   posite of twenty individual oysters. Each year. the field
         ages. and spills of petroleum or petroleum products).                   sampling returned to as many sites as possible. In some
           The contaminants found in oysters reflect the current                 instances it was necessary to relocate or abandon an
         contaminant burden of an ecosystem. The concentra-                      Table 1. National Status and Trends Oysters Gulf of Mexico
         tion of a contaminant in an oyster is the difference                              Sampling Program-Summary of sampling
         between uptake and excretion of that contaminant.
         Galveston Bay oysters transplanted from a 'high' level                                             1986     1987    1988     1989     1990
         site to a 'low' level site. and vice versa. come to a new
                                                                                 Year                         I       II       III     IV       V
                                                                                 Number of sites              49      48       65      62       68
         Environ. Pollut. 00269-7491'94'506.00 C 1993 Elsevier Science         Number of samples              142     144      195     186      203
         Publishers Ltd. England. Printed in Great Britain

                                                                            291


                                                                                       1-89



















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                                                 PAH contaminants in oysters from the Gulf of Mexico

established oyster site due to lack of suitable seed			Gas chromatography - mass spectrometry (GCC-MS)
bivalves (Wilkinson et al., 1991).  The locations and			PAHs were separated and quantified by GC-MS
designator for the oyster sites are found in Wilkinson et		(HP5980-GC interfaced to a HP5970-MSD).  The sam-
al. (1991). Sericano et al. (1990) and Wade et al. 			ples were injected in the splitless mode on to a 30 m
											X0.25 mm (0.32 m film thickness) DB-5 fused silica
Tissue extraction									capillary column (J&W Scientific Inc.) at an initial tem-
The tissue extraction process used was adapted from a 		perature of 60 C and temperature programmed at
method developed by MacLeod et al. (1985).  Approxi-			12 C/min to 300 C and held at the final temperature
mately 15 g of wet tissue were used for the PAH				for 6 min.  The mass spectral data were acquired using
analysis.  After the addition of internal standards (surro-		selected ions for each of the PAH analytes.  The
gates) and 50 g of anhydrous NA2SO4 the tissue was			GC-MS was calibrated and linearity determined by
extracted three times with dichloromethane using a			injection of a standard containing all analytes at five
tissuemizer.  A 20 ml sample was removed from the total		concentrations ranging from 0 01    to 1 
solvent volume and concentrated to one ml for 				Sample componenet concentrations were calculated
percentage determination.  The 280 ml of remaining			from the average response factor for each analyte
solvent was concentrated to approximately 20 ml in a 			Analyte identifications were based on correct retention
flat-bottomed flask equipped with a three-ball 				time of the quantitation ion (molecular ion) for the 
column condenser.  The tissue extract was then trans-			specific analyte and confirmed by the ratio of quantita-
ferred to a Kuderna-Danish tube heated in a water 			tion ion to confirmation ion.
(60 C) to concentration the extract to a final volume of			Calibration check samples were run with each set of
2 ml. During concentration.  the dichloromethane was			samples (beginning, middle, and end).  with no more
exchanged from hexane.								than 6 h between calibration checks.  The calibration
	The tissue extracts were fractionated by aluminatisilica	check must maintain an average response factor within
(80-100 mesh open column chromatography.  The				10% for all analytes with no one analyte greater than
silica gel was activated at 170 C for 12 h and partially		+25% of the known concentration.  A laboratory refer-
deactivated with 3% distilled water (ww).  Twenty			ence sample (oil spiked solution) was also analyzed
grams of silica gel were slurry-packed in dichloro-			with each set of samples to confirm GC-MS system
methane over 10 g of alumina.  Alumina was activated 			performance and calibration.
at 400 C for 4 h and partially deactivated with
distilled water (ww).  The dichloromethane was replaced		RESULTS AND DISCUSSION
with pentane by elution.  The extract was then applied
to the top of the column.  The extract was sequentially		Oyster site variations
eluted from the column with 50 ml of pentane (aliphane		During the first five years of this study a total of 870 
fraction) and 200 ml of 1:1 pentane: dichloromethane			composited oyster samples have been analyzed for
(aromatic fraction). The aromatic  fraction was further		PAHs.  The PAH (total NS&T PAHs) is the sum of the
purified by HPLC to remove the lipids.  The lipids were		eighteen aromatic hydrocarbon analytes. as measured in
removed by size exclusion using dichloromethane as			Year 1. with concentrations greater than 20 ngg dry wt
an isocratic mobile phase (7 ml min) and two 225 			(Table 2): this was the reporting limit for Year 1 data
250 mm Phenogel 100 columns (Krahn et al., 1955).			(Wade et al., 1981).  The median PAH concentration at 
The purified aromatic fraction was collected from			a site is used as a measure of the best indicator of the
15 min prior to the elution of 4.4 - dibromofluoro-			concentration.  The median is a more stable (or resistant)
biphenyl to 2 min. after the elution of perylene. The
retention times of the two marker peaks were checked			Table 2.  National Status and Trends oysters polynuclear
prior to the beginning and at the end of a set of 10						aromatic hydrocarbon analytes
samples.  The purified aromatic fraction was concen-							Aromatic hydrocarbons
trated to 1 ml using a Kuderna-Danish tube heated in		
a water bath at 60 C.
	Quality assurance for each set of ten samples in-		Low molecular weight				High molecular weight
cluded a procedural blank.  matrix spike. duplicate. and		Biphenyl						Fluoranthene
tissue standard reference material (NIST-SRM 1974)			Naphthalene						Pyrene
which were carried through the entire analytical scheme.		1-methylnaphthalene				Benz(a)anthracene
Internal standards (surrogates) were added to the sample		2-methylnaphthalene				Chrysene
prior to extraction and were used for quantitation.  The		2.6-dimethylnaphthalene				Indeo[1,2,3-cd]pyrene
surrogates were d-naphthalene.   d-acenaphthene.			1.6.7-trimethylnaphthalene			Benzo(a)pyrene
d10-phenanthrene d -chrysene. and d-perylene.  Surro-			Acenaphthene					Benzo(e)pyrene
gates were added at a concentration similar to that 			Acenaphthylene					Perylene
expected for the analytes of interest.  To monitor the		Fluorene						Dibenz(a,h)anthracene
recovery of the surrogates. chromatography internal			Phenanthrene					Benzo(g,h,f)perylene
standards d10-fluorene and d12-benzo(a)pyrene were			Anthracene
added just prior to GC-MS analysis.						1-methylphenanthrene
											Analytes not used in tPAH summation.

											1-91 






                     294                                                                    T J Jackson et al.


                                                                          Table 3. Total N'S&T PAK concentration in oysters

                     "'0,     Site             Median concenir---ori of tPAH              Bay group               No.   Site            Median concentration of tPAH                BaN gr1up
                              code                                                        median                        crkje!                                                         median
                                             V       IV           111     11      1       (ng:g)                                      V           IV      III      if            I     (ng;g)
                                             1990    1989         198@  @4@'7  1996                                                1990           1989    1988     1987          1986
                     Texas                   (11grg) (ng gi       kng SP  g@ (ng,g)                               Louisiana-cont   (ng g)         (ng g)  (ng,g) (ngrg)    Ing,g)
                          I   LMSB           22      20           30      20      25                              65    MRTP          212         310     1410     -             -  391 t 582
                          52  LMPI           -       -            31,80   -       -       30 ï¿½ 58                 64    \IRPL         403         '30     695      -             -
                          78  LMAC           120     -            -       -       -                               31    BSSI          185         71      484      68            177 181 t 134
                          53  CCBH           1530    -            1 600   -       -                               30    BSBG          45          202     213      118           265
                          2   CC\B           161     264          59S             45      565 ï¿½ 725               32    LBMP          20          84      89       26            20 39+-59
                          3   CCIC           137     430          848          1  140                             62    LBNO          -           -       81       -             -
                          54  ABHI           -       -            1870            -
                          4   ABLR           20      20           20      1       20                              Mississippi
                                                                  10      10                                      33    MSPC          103         300     175      114           99
                          5   CBCR           88      -            -               22      20-- 1                  4     MSBB       1  110'        893     1500  4  110    1 600     3,22 t 6_54
                          (3  \A BN R        20      20           20      10      21                              35    MSPB          59          306     776      300           246
                          7   SAPP           26      -            -       ; 1     45                              Alabama
                          8   S.4,\lp        -       -            -       .19     93      25                      3 6   M BCP         20          90      288      1 -3, 7       1
                          9   ESSP           20      -            -               20
                                                                                                                  66    MBHI          761         554     1110                      295    -40
                          10  ESBD           11      70           11              -                               79    MBDR       1  520         -       -
                          12  MBGP           -       20           86              20                              Florida
                          I 1                96      348          -       ;9      90      45      48
                                                                                                                  67    PBPH          168         369     842
                          56  MBCB           20      -            ;6      -       -
                                                                                                                  3,7   PBIB          -           ZI      204      250           406 197   198
                          13  MBTP           20      20           @6      10      20                              8@    PBSP          130         -       -        -             -
                              MBDI           -       -
                                                                                                                  73    CBJB       1  680         8590    -        -             -
                          14  MBEM           201     200                          78      138 ï¿½ 119                                               -
                                                                                                                  39    CBSP          225         4@      703      543           418 429ï¿½ 1 140
                          7?  BRCL           761     60                                                           38    CBSR          69          21      24;40 2470             209
                          57  BRFS           95 5 1  670          682             -       792 ï¿½ 792               74    PCLO          98          129     -        -             -
                          18  GBCR           370  1  170          52@          1 070                              68    PCMP       1  210         26()0   4 750    -             -I goo ï¿½ 1 ;90
                          5 8 GBOB                   593          54"             -                               40    S. -% V @ B1  150         2 090   1990  1 970   11       800
                          16  GBTD                   44           20      i2      149     259 ï¿½ 606                                               14
                                                                                                                  41    APDB          20                  2 800    20            20 57 ï¿½ 530
                          t;  GBYC           247.    1            207  -@s     1  0110                                                            -       740          t)
                                                  I  -                                                            42    APCP          269         1110                           109
                          .9  GBSC           1290    . @O         3100
                          17  GBHR           20      119          -'4     10                                      75    AESP          -3          74      -        -             -
                     Louisiana                                                                                    69    SRN\'P        -           -       119      -             -
                          19  SLBB           108     154          169     26      247     1 @4    72              43,   CKBP          20          74      1-4      69            22 46     103
                          20  CLSJ           180     1-28         10-1            '76     220     218             /6    TBN?          269         194
                          60  CLLC           404     726          20                                              47    TB%IK         101         1@0     -?0      49
                                                                                                                  44    TBPB          20          2!7     2 86     68            9@;
                          21  JHJH           88      72           20      S4      43      44-- 50                 70    TBOT          112         ',;7    __12     -             -  126 t 165
                          22  VBSP           189         1                        79      79      108                   TBKA          252         S,4     -        -             -
                          'N  ABOB           20      18           192             -'2     '2      42              45    TBHB          -           -                1             460
                          2 5 CLCL           20      54           20      0       20                              46    TBCB          20          6;      94       12            20
                                             10                                                                   48    CBBI          20                  31       41            20 ;1 _+ 180
                          26  TBLB                   49           306             20      40+-    162
                          _27 TBLF           101     50           8-'             -15                             71    CBFM          69          ;16     27-1     -             -
                          61  BBTB           -       -                            -                               49    \BNB          8_1         20",    2 4; 11  108           1-1-8 7_1 ï¿½ 129
                                                                                                                  50    RBHC          20          @7      6-7      10            4-7
                          28                                                              96' ï¿½   1 020
                              BBSD           963 5 480            44              -7
                          29  BB%IB          1080 1 ' 80          1 46C)  41)     822                             1     ENTU          47          68      2        20            112 68 ï¿½ 125



                     estimator of the tvpIcal value than, the mean for data                                       MBLR. MBCB. MBTP &                      MBDI) and Aransas bavs
                     which ma,, contain outliers (Hem.-I. 1990).                                                  (ABLR. CBCR & MBAR)                     which exhibit low median
                                                                                                                                                                                       in con-
                          The data in Table 3 presents th, spatial and temporal                                   concentrations of tPAH and small variability                         '
                     variation for the median tPAH concentration in the                                           centration. The highest median tPAH concentration for
                     coastal and estuarine areas of the Gulf of Mexico. The                                       a bay group in Texas is the Brazos River (BRCL &
                     sites are separated into Bay groups (Wilson et al.. 1992)                                    BRF'S). which carries the runoff from agriculture and
                     for data comparison. The vaniability for each Bay                                            wastewater discharge from industrial point-sources
                     group is the standard deviation @_;; computed from the                                       (NOAA. 1985). For the entire coastal and estuarine
                     interquartile range OQR) for th.-. five years of data                                        area of the Gulf of Mexico (Table 3). the highest
                     (Hensel. 1990). In Texas. Co-,pus Ch'risti (CCBH.                                            median tPAH concentration for a bay group is near
                     CCNB, CCIC & ABHl) and Gaixeston bays (GBCR.                                                 Panama Cirv. Florida (PCLO. PCMP & SAWB),
                     GBOB. GBTD. GBYC. GBSC & GBHR) are near                                                      which is close to a paper mill (NOAA. 1985. Wilkinson
                     industrial and population cent.-7s and exhibit high                                          ei al.. 1991 @.                                                                                           I
                     median concentrations of tPAH and laree variability in                                       There are fifteen sites (LMSB. ABLR. CBCR.
                     concentration compared to Matagorda (ESBD. MBGP.                                             MBAR. SAPP. ESSP. ESBD. MBGP. MBCB. MBTP.



                                                                                                                  1-92






                                                           PAH contaminants in oysters from the Gulf of Mexico                                                                    295

                                    NS&T PAH Data - Years I to V                                                               NS&T PAH Data - Years I to V
                  500
                                                                                               

                                                                                               
                  400
                  300                                                                                  

            
                                                                                                       
                                                                                                     



                  200



                  100
                                 CLCL-1             CLCL-2              CLCL-3
                                               Site and Station                                                                   Median of Site NS&T 

            Fig. 2. Total NS&T PAH concentration distribution during                                   Fig.  4. Frequency distribution of the median total NS&T
            the first five years for all three stations: Caillou Lake in                               PAH (tPAH) concentration in the Gulf of Mexico during the
                                Louisiana (Site 25-CLCL).                                                                  first five years of the program.


            CLCL. LBMP. TBCB. CBBI & RBHC) with low                                                    Cumulative frequency model
            concentration of tPAH (< 100 ng/g) and little variation                                    Bar graphs (Wade et al. 1990) or crossplots (Wade &
            in the observed values (Fig. 2). There are also six sites                                  Sericano. 1989) of data comparing one year's data with
            (GBSC, BBMB, MSBB. CBJB. PCMP & SAWB). of                                                  another have been used to display the general trend for
            the seventy-eight different sites. where high concentra-                                   tPAH data (Wade & Sericano. 1989: Wade et al. 1990:
            tions of tPAH (>1000 ng/g) are observed. Four sites                                        Wade et al. 1991). These data presentations easily
            (CCIC PBPH. PBIB & PCMP) exhibited a decrease in                                          visualize the variation in concentration for a particular
            the tPAH each year during the first five years of this                                     site. In this report the cumulative frequency function is
            study. Many sites exhibited a cyclic variation with time.                                 used to examine the heterogeneous distribution of PAHs
            At Choctawatchee Bay off Santa Rosa (CBSR. Fig. 3).                                       in Gulf of Mexico oysters (Mackay & Paterson. 1984).
            the order of magnitude increase in concentration of                                        This approach has the advantage of examining the Gulf
            tPAH in Years II and III is probably due to relocation                                     of Mexico as a single environmental system. determining
            of the collection site to an area containing wood pilings.                                 the percentage of sites exposed to a particular threshold
            which if treated with creosote. are a source of PAHs.                                     concentration. and providing information for environ-
            The decrease in Years IV and V probably reflects relo-                                    mental evalualion.
            cation of the collection stations to an oyster reef away                                     The distribution of the PAH data in Table 3 is best
            from wood pilings. Due to prolonged freshwater condi-                                      described by a lognormal distribution i.e. the distribu-
            tons in San Antonio Bay during 1988 and 1989 (Years                                       tion of data is skewed to low concentrations and has a
            III IV). the oyster reefs experienced a die-off resulting in				      fraction which extends to high concentrations (Fig. 4).
            no oysters being taken from SAPP. SAMP and ESSP.                                           O'Connor (1990) used the lognormal distribution.
                                                                                                       typical of environmental data. to define high concentra-
                                    NS&T PAH Data - Years I to V                                      tions as those whose logarithmic value is more than the
                                                                                                       mean plus one standard deviation of the logarithms for
                                                                                                       all conctntrations. The tPAH data in Fig. 4 is further
                  4500                                                                                skewed in that analytes with concentrations less than
                  4000                                                                                 20 ng g are not included in the sum of eighteen 2-5
                  3500                                                                                   ring aromatic hydrocarbon analytes in Table 2. i.e. the
                  3000
                                                                                                        data   has been censored. For Years I-III, on1y censored
                  2500                                                                                  data   was available. whereas for Years IV and V both
                  2000                                                                                censored and uncensored data was available. A regres-
                                                                                                       sion analysis of the censored (tPAH) data versus
                  1500                                                                                  uncensored data for the sum of all analytes (T-PAH) in
                  1000                                                                               Table 2 from Years IV and V yields the best fit line as
                                                                                                       y = 153-0 + 0.9834 x (r2 = 0.99289): where y = uncen-
                  50O                                                                                  sored data. and x = censored data. Using the best fit
                      0                                                                               line from the Year IV and V data. the censored data
                                 CBSR-1              CBSR-2             CBSR-3
                                                site and station                                       for the cumulative frequency data was corrected to be
            Fig. 3. Total NS&T PAH concentration distribution during                                   the same as the uncensored cumulative frequency data.
            the first five years for all three stations: Choctawatchee Bay                                Distribution functions are useful measures of environ-
                              off Santa Rosa (Site 38-CBSR).                                           mental quality data in that changes with time can be
                                    
                                    
                                    
                                    
                                    







                                                                                                             1-93









                          296                                                                                 T J. Jackson et al.




                                                                                                                                                                                                                                              
                                                                                                                                                                                                                 
                             
                                                    Total NS&T PAHs (ppb)                                                                                     Total NS&T PAHs (ppb)
                          Fig. 5.    Plot of the cumulative frequency distribution                             				Fig. 6. Plot of the cumulative frequency distribution for Year
                          V total NS&T PAH (PAH) concentration. compared to the                                                      V NS&T PAH (PAH) concentration. compared to the
                          Gaussian curve and its cumulative frequency distribution gen-                                              Gaussian curves and their cumulative frequency distributions
                          erated from a lognormal model with a mean of 250 ppb and                                                   generated from a two population lognormal model with a
                                                     standard deviation of 218.                                                     mean of 214 ppb for Population I and a mean of 1205 ppb
                          ascertained without being influenced by outliers. For                                                                                    for Population 2.
                          tile cumulative distribution plot. the data is sorted from                                                 computed. but did not compare as well with the actual
                          the lowest value to the highest. similar to rank trans-                                                   data for Year V.
                          formation (Conover & Iman. 1981). Each observation                                                            The implication of the two populations in the data is
                          is I n fraction of the data set. where n is the number of                                                 that there are two primary mechanisms accounting for
                          samples in the data set. The sum of the fraction of the                                                    the distribution of T-PAH concentration in the Year V
                          samples less than the concentration is plotted against                                                     data. The sites with lower concentration PAHs are prob-
                          the concentration., From this plot the median can be                                                       ably due to low level background inputs from storm-
                          determined. since it is defined as the 50th percentile.                                                    water runoff. atmospheric deposition and sewage
                          The interquartile range (IQR) is used a measure of                                        effluents. etc. (NOAA. 1985). The sites with higher con-
                          variability. The lQR is the 75th percentile minus the                                                      centration PAHs are probably due to local point-sources
                          25th percentile and equals 1:35 times the standard                                                         of PAH contamination (i.e. small spills). From the log
                          deviation for a normal distribution (Hensel. 1990).                                                        normal cumulative frequency function two probability
                              To begin the examination of the distribution of the                                                    density functions were derived. the relative proportion of
                          PAH concentration data, the logarithm of the sum of                                                        the two populations were estimated to be 0.9 for popula-
                          all PAH analytes (T-PAH) for Year V data was plotted                                                      tion one and 0.25 for population two. Comparison of
                          as a cumulative frequency distribution. The 50th                                                          the cumulative frequency distribution derived from the
                          percentile was 250 ppb and the standard deviation as                                                       sum of the two probability density functions. in the
                          determined from the  IRQ was 218. The log of the data                                                  above proportions. with the actual data for the cumula-
                          versus fraction of the samples was plotted and com-                                                       tive frequency distribution (Fig.7) indicates a good
                          pared with a lognormal distribution (fig. 5). The shape                                                    correlation.
                          of the cumulative frequency curve (i.e. the positive
                          deviation from the lognormal model for the T-PAH
                          data suggests two overlapping lognormal distributions.
                          Making the assumption that there is a 25 overlap for
                          the two distributions. the mean and standard deviation

                                                                                                                             
                              were computed for each data set. or population (Table
                                                                                                                                                                  4). Tile cumulative frequency distribution from the two
                          population model data compare well with the actual                                                                                                                                                                                                              
                          T-PAH data (Fig. 6). Other increments of overlap were
                                                                                                                                                                                                                                                                                              
                                                                                                                                     Fig. 7. comparison of the cumulative frequency distributions
                                                                                                                                     for the actual Year V total NS&T PAH (PAH) concentra-
                                       
																					        tion data and the cumulative frequency distribution generated
                                                                                                                                                            from the two population model.







                                    PAH contaminants in oysters from the Gulf of Mexico                                                                                                        297

                       Table 5. Two population lognormal distribution model. Corrected tPAH data-ng/g dry weight

                  Year                         Median               Population I                     Population 2
                   1                                            mean (log)      std (log)            mean (log)          std (log)
                   11                                           197(2.294 5)     108 (0.229 8)        1 075 (3.031 4)    714 (0.277 2)    
                   111                                          186 (2.269 5)    87 (0.196 7)         1 150 (3.059 9)    1 100 (0.381 1)
                   IV                                           259 (2.413 3)    216 (0.343 5)        1 910 (3.280 8)    1 190 (0.261 8)  
                   V                                            269 (2.429 8)    174 (0 250 0)        1 350 (3.131 6)    1 190 (0.303 9)                                                                    212 (2 326 3)    131 (0 263 9) 
                                                                                                      1 170 (3.068 9)    637 (0.243 5) 



                     Since historical NS&T data (Table 3) is censored                                                               tration. while Year III had 80%. Year IV had 83%.
                  data ( Wade et al lass: Wade & Sericano. 1989: Wade                                                              and Year V had 87%. Alternatively. the cumulative
                  et al.. 1990 the acmulative frequency distribution of                                                           frequency data can be used to calculate the percentage
                  this censored (pah data was corrected using the best-                                                           of sites exposed to a concentration in excess of a partic-
                  fit-line from the or Years IV and V. Data below                                                                 ular threshold.
                  the reporting limit were extrapolated (Hensel. 1990:                                                              The cumulative frequency distribution was used in
                  Mackay & Paterson 1984). The summary statistics for                                                             this study as an environmental evaluation tool to
                  the corrected date using the two population model for                                                            examine the heterogeneous distribution of total PAH
                  Years I-V data (TABLE 5) were calculated using the data                                                         contaminants in Gulf of Mexico oysters from coastal
                  from 0-80 for the original cumulative frequencv distri-                                                         and estuarine areas collected during the winters of
                  bution for popultion 1 and from 77.5-100% for the                                                               1986-1990. The PAH concentrations exhibits a log-
                  original cumulative frequency distribution for popula-                                                          normal distribution with two major populations in the
                  tion 2 (Table 6).                                                                                               data for each year. The two populations were decon-
                     The summary statisitcs for the first five vears of                                                           voluted into probability density functions and sum-
                  measuring PAH conaminants in the Gulf of Mexico                                                                 mary statistics for each population were calculated.
                  for NOAA's NS&T Mussel Watch Program (Table 5)                                                                  The lower PAH concentrations are probably related to                                              related to
                  show variation in the means for both populations. indi-                                                         chronic inputs. Many of these low PAH concentration
                  cating temporal change in the total Gulf of Mexico                                                              sites show little variability from year to year. support-
                  data and with the highest values found in Years III and                                                         ing the contention that the PAH contamination  is on a
                  IV. The higher mean concentrations  of PAHs in Years                                                            continual basis. The higher concentration PAHs are
                  III and IV and the lower abundance in Years 1. 11 and                                                           probably associated with local point-sources of PAH
                  V is a pattern which is probably related to large-scale                                                         contamination or spills. Most of the NO concentration
                  climatic factors such as the El Nino cycles (Philander.                                                         sites (>1000 ng g dry tissue) show largee variability
                  1989) which affects the precipitation regime (Wilson et                                                         from year to year supporting the contention that PAH
                  al.. 1992). Examination of the PAH data for individual                                                          contamination for these sites is on an episodic basis. In
                  sites. as discussed above does not show this pattern.                                                           addition 20% of Gulf of Mexico sites Year III were
                     The cumulative frequency data for Years I-V gives                                                            exposed to a PAH threshold concentration of greater
                  the percentage of sites whose PAH concentration is less                                                         than 1000 ng/g of dry oyster tissue. Whereas. in Years I
                  than a particular concentration (Table 6). As an exam-                                                          and 11 only  II of the Gulf of Mexico sites had
                  ple. using 1000 ppb as an arbitrary concentration. 89%                                                          concentrations greater than 1000 ng g of total NS&T
                  of the sites for Years I and 11 are less than this concen-                                                     PAHs. The changes in the mean concentration of the
                                                                                                                                  two populations between years display a cyclic patte
                                                                                                                                  which is probably due to large scale climatic factors
                  Table 6. NS&T concentration distribution data (cumulative
                           frequency). Corrected tPAH data-n/g dry weight                                                         such as the El Nino cycles which affects the precipita-
                                                                                                                                  tion regime (Wilson et at..1992). The cyclic pattern
                                 1990             1989                  1988            1987               1986                   was obtained by examining the Gulf of Mexico as a
                                Year V           Year IV                Year III       Year 11             year I                 single heterogenous system. since the PAH concentra-
                                                                                                                                  tion data for individual sites does not clearly show this
                  10%           110                171                  110               110                110                  pattern.
                  20%           140                200                  153               140                140                                                                              226                  206               162                169               140
                  30%           164                249                  259               186                197
                  40%           212                352                  345               208                229
                  50%           270                435                  445               258                286                 ACKNOWLEDGEMENTS
                  60%           3188               539                  832               370                378
                  70%           397                510                 1030               480                557                 Funding for this research was supported by the
                  80%           597                869                 2090               1300              1180                 National Oceanic and Atmospheric Administration.
                  90%          1020               1440                                                                           contract number 50-DGNC-5-00262 (National Status
                                                                                                                                 and Trends Mussel Watch Program),through the Texas 
                                                                                                                                 A & M Reseach Foundation. Texas A& M University.     







                 298                                                           T J. Jackson et aL

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                 Mackay. D. & Paterson. S. (1984). Spatial concentration                         G. J. & Jackson. T. J. (1991). Oysters as bimonitors of  
                    distributions environ. Sci. Technol., 18.207A-1 4A.                       oil in the ocean. Proceedings of the Annual Offshore
                 MacLeod. W. D.. Brown. D. W.. Friedman, A.J. Burrows,                        Technology Conference, OTC 6529. pp.
                    D. G.. Maynes. 0.. Pearce. R. W.. Wigren. C. A. & Bogar.                  Wilkinson, D. L.. Brooks. J. M. & Fay.R. R. (1991). NOAA
                    R. W. (1985). Standard analytical procedures of the NOAA                     Status and Trends: Mussel Wtch Program-Field
                    National Analytical Facility 1985-1986. Extractable Toxic                    Sampling and Logistics Report-Year VI. GERG Technical
                    Organic Compounds. 2nd Ed. US Department of Commerce.                        Report 91-046. US department of commerce national
                    NOAA/NMFS NOAA Tech. Memo NMFS F/NWC-92.                                     oceanic & atmospheric administration. ocean assessment   
                             Division.                             
                    Strategic Assessment: Data Atlas. United States Depart-                   Wilson. E. A.. Powell. E. N.. Wade. T. L.. Taylor. R. J..
                    ment of Commerce. National Oceanic and Atmospheric                           Presley. B. J. & Brooks, J. M. (1992)Spatial and temporal
                    Administration. pp. 4.0-5.32.                                               distributions of bodv burden and disease in the Gulf of
                 O'Connor. T. P. (1990). Coastal Environmental Quality in                        Mexico oyster populations: The role of local and large-
                    the United States. 1990. Chemical Contamination in Sedi-                     scale climatic controls. Helgol. Measurments. (in press).































                                                                                              1-96
 

















                          Reprint 10

          Butyltin Concentrations in Oysters from the
               Gulf of Mexico During 1989-1991


            Bernardo Garcia-Romero, Terry L. Wade,
            Gregory G. Salata and James M. Brooks


















                              1-97







            Environmental Pollution 81 (1993) 103-4 11




                        BUTYLTIN CONCENTRATIONS IN OYSTERS FROM
                                THE GULF OF MEXICO FROM 1989 TO 1991


                     Bernardo Garcia-Romero, Terry L. Wade,* Gregory G. Salata & James M. Brooks
                         Di@parlment of Oceanoyraphy, Texas A & M University, Geochemical and Environmental Research Group,
                                                 833 Graham Road, College Station, Texas 77845, USA

                                                     (Received 4 March 1992; accepted 2 June 1992)


            Abstract                                                            1991; Waite et al., 1991). In the USA, however, contin-
            Oyster samples from 53 Gu?f qf Mexico coastal sites                 uous monitoring is needed in order to provide informa-
            were collected and analyzed for butyltins during 1989,              tion on the long-term response of butyltin concentrations
            1990, and 1991. The geomeiric-mean tributylin concen-               in the marine environment to these regulations.
            trations were 85, 30, and 43 ng Sng for 1989, 1990, and                Oysters are excellent sentinels of TBT contamina-
            1991, respectively. 77te tributyltin concentrations are best        tion. Bivalves have been used in uptake and depuration
            represented by a log-normal disribution. A decline in the           studies (Laughlin et al., 1986; Langston & Burt, 1991;
            butyltin concentrations at sites with relatively low                Sericano ei al. (in press); Alzieu ei al., 1991; Ritsema
            butyltin concentrations for 1989 compared with 1990 and             et al... 1991; Salazar & Salazar, 1991) and to determine
            1991 was observed, and, at relarively high butyltin con-            temporal and spatial variations of butyltin concentra-
            centrations (>400 ng Sn1g), there was hardly any differ-            tions (Short & Sharp, 1989; Wade ey al., 1988; Page &
            ence between 1989 and 1991, but lower concentrations                Widdows, 1991). These studies indicated that oysters
            were present in 1990. Continued monitoring is needed in             integrate bioavailable TBT with equilibration rates in
            order to determine if butyltin contamination of the                 the order of weeks. This indicates that continuous and
            coastal marine environment is decreasing in response to             carefully planned sampling should be carried out in
            use limitations.                                                    order to deterrnine trends in the variation of TBT
                                                                                concentration in the environment.
            LNITRODUCTION                                                          Tributyltin and its degradation products were deter-
                                                                                mined in oysters from 53 sites in the Gulf of Mexico
            The presence of tributyltin and its degradation products            from 1989 to 1991. The over-all butyltin concentrations
            in the environment continues to be of environmental                 showed a decline from 1989 to 1990 (Wade et a].,
            concern. Tributyltin (TBT) ann-fouling paints are a                 1991a.b). If this decline resulted from the implementa-
            solution to the costly problem of fouling organisms                 tion of the limitations on the use of TBT in the USA by
            that attach to the bottom of the hulls of boats and ships           the Organotin Anti-Fouling Paint Control Act of 1988
            (Huggett et aL, 1992). Although an effective anti-fouling           (OAPCA). a continuous decline would be expected. The
            agent, tributyltin, was found to a5ect non-target organ-            results are now available for 1991. This report compares
            isms adversely (Bushong et al.. 1987; Hall & Pinkney,               three years of data for the Gulf of Mexico to determine
            1985; Minchin et aL. 1987; Short & Thrower, 1986;                   if there is a trend in butyltin concentrations.
            Thain, 1986, Thompson et al., 19S5; Alzieu, 1991). For
            example, commercially valuable species were adversely
            affected in France (Alzieu, 19911. The presence of TBT              N1ETHODS
            and its degradation products., dibutyltin (DBT) and
            monobutyltin (MBT), in samples removed from input                   Oyster (Crassostrea virginica) samples were collected
            sources (Wade et al., 1988; 1991b) suggests that envi-              at 73 different sites along the Gulf of Mexico coast in
                                                                                the winters of 1989, 1990, and 1991. Table I shows
            ronmental half-lives in the marine environment may be               the geographic location of the sites sampled and the
            longer than reported values (Lee et al., 1987; Olson &              symbols used to identify each site. Although knoAm
            Brinckman, 1986; Seligman et aL. 1986ah, 1988). After               point sources of TBT such as marinas or dry docks
            the use of TBT-based pain@s was limited in countries                were avoided, some locations are closer to such TBT
            such as France, England, and the USA, the concentra-                sources. A complete description of field sampling and
            tion of organotins in water and oysters was shown to                logistics has been reported (GERG, 1991).
            decline (Short & Sharp, 1989, Wade et al., 1991b;                     The same sampling and analytical procedures were
            Alzieu, 1991; Page & Widdows. 1991; Valkirs et aL,                  used for all oyster samples reported. A detailed descrip-
            . To whom correspondence should be addressed.                       tion of these procedures has been previously reported
            Environ. Pollut. 0269-7491/93/SO6.00 C 1993 Elsevier Science        (Wade et al., 1988; Wade & Garcia-Romero. 1989).
            Publishers Lid, En,land, Printed in G-mat Britain              103  Brieft, oyster tissues were homogenized, weighed,
                                                                                     1-99






                                                                      Table 1. Sampling locations and site designators

                   Designation                           Site                                     Location                            Latitude                       Longitude
                                                                                                                                    (dog)      (-in)               (deg)     i.min)

                                                                                               TEXAS
                   LMSB                         Sou,.h Rav                             Lower Laguna Madre                            26        02-58                 97      10-49
                   LMAC'                        Arro%,- 61orado                        Laguna Madre                                  26        16-80                 97      1730
                   CCBR*                        Boa-. Harbor                           Corpus Christi                                27        50-00                 97      2@-00
                   CCNIV                        Nuo.---@i Bay                          Corpus Christi                                27        51-70                 97      21-00
                   CCIC                         Ingimie Cove                           Corpus Christi                                27        50-30                 97      14-25
                   ABLR                         Long Reef                              Aransas Bay                                   28        03-30                 %       57-50
                   CDCRO                        Copan, Reef                            Copano Bay                                    28        08-20                 97      07-58
                   MBAR                         A)T-- Reef                             Mesquite Bay                                  28        10-30                 %       49-70
                   SAPP`                        Panthz.- Pt. Reef                      San Antonio Bay                               28        13-20                 %       43-00
                   SAMPO                        Moscuito Point                         San Antonio Bay                               28        19-00                 %       42-20
                   ESSPO                        South" Pass Reef                       Espiritu Santo Bay                            28        17-83                 %       37-50
                   ESBDP                        Bill Dz%s Reef                         Espiritu Santo Bay                            28        25-00                 %       27-00
                   MBGPO                        G&U-- p'per Pt.                        Matagorda Bay                                 28        35-00                 %       -14-00
                   MBLR                         Lava: River Mouth                      Matagorda Bay                                 28        39-30                 96      35-00
                   MBCB4                        Caranzabua Day                         Matagorda Bay                                 28        40-00                 96      23-20
                   MBTP                         Tres Pz:acios Bay                      Matagorda Bay                                 28        39-00                 96      15-50
                   MBEM                         Eas: Matagord'                         Matagorda Bay                                 28        42-30                 95      511-00
                   BRCL*                        Ccd@- Lakes                            Brazos River                                  28        51-50                 95      27-90
                   BRFS                         Frernor, River                         Brazos River                                  28        55,00                 95      20 50
                   GBCR                         Con3::1Z'-ratc Reef                    Galveston Bay                                 29        15-75                 94      50-50
                   GBOB                         Offa-:@ Bayou                          Galveston Bay                                 29        16-70                 94      50-70
                   GBTD                         Todd% Dump                             Galveston Bav                                 29        30-10                 94      54-00
                   GBYC                         Yach: Club                             Galveston Ba@                                 29        37-00                 94.     59-50
                   GBSC4                        Ship Channel                           Galveston Bay                                 29        42-50                 94      59-50
                   GBHR                         Hanrz Reef                             Galveston Bay                                 29        29-50                 94      42 50
                   SLBB                         Blue B---zk Point                      Sabine Lake                                   29        48-00                 94      .14-42
                                                                                            LOUISIANA
                   CLS]                         St. Jo@- Island                        Calcasieu Lake                                29        50-00                 93      32-00
                   CLLC                         Lake Charles                           Calcasieu Lake                                30        03-50                 93      1750
                   JHJH                         Joseph Harbor Bayou                    Joseph Harbor Bayou                           29        37-75                 92      45-75
                   VBSP                         Southu-st Pass                         Vermillion Bay                                29        34-70                 92      04-00
                   ABOB                         Oysic.- Bayou                          Atchafalaya Bay                               29        13-00                 91      08-00
                   CLCL                         Ciillo-- Lake                          Caillou L@k                                   29        15-25                 90      55 50
                   TBLB                         Lake Ba-re                             Terrebonne Bay                                29        15-00                 90      16-00
                   TBLF                         Lake Ftlicity                          Terrebonne Bay                                29        16-00                 90      2450
                   BBSD                         Bavo-.; S,.. Denis                     Barataria Bav                                 29        24-10                 89      ;9180
                   BBMB                         M;ddiz Bank                            Barataria Bay                                 29        17-20                 89      56-60
                   MRT?                         Tile. P--5s                            Mississippi River                             29        08-69                 89      25-67
                   MRPV                         Pass a Loutre                          Mississippi River                             29        04-30                 89      04 60
                   BSSI                         Sabie as'and                           Breton Sound                                  29        24-70                 89      28-70
                   BSBG                         Ba, G:-derne                           Breton Sound                                  .19       35-87                 89      38 50
                   LBMP                         Milhe-.:7eux Point                     Lake Borgne                                   29        52-30                 89      4070
                   LPGOO                        Gull a-let                             Lake Ponchartrain                             30        02-20                 89      01-00
                                                                                           MISSISSIPPI
                   MSPC                         Pass C@%-nstian                        Mississippi Sound                             30        19-75                 89      1958
                   MSBB                         Bilm i.".                              Mississippi Sound                             30        23-38                 88      15-42
                   MSPR                         Pasmzo@iia Bav                         Mississippi Sound                             30        21-05                 88      17-00
                                                                                            ALABAMA
                   MBCP                         Ceda- Point Reef                       Mobile BaN                                    30        19-40                 88      07 , .30
                   MBHJ                         Har6,-r Island                         Mobile Ba%                                    30        33-59                 88      02-80
                   MBDRO                        Dog R--%-er                            Mobile BaN                                    30        35-50                 88      0272
                                                                                             FLORIDA
                   PBPH                         Public Harbor                          Pensacola Bay                                 30        M-80                  87      11-50
                   PRIBO                        Indian Bayou                           Pensacola BaY                                 30        30-83                 87      04-00
                   PBS1319                      Sabint Point                           Pensacola Ba%                                 30        20-80                 87      OS-10
                   CBJB                         Joes BZ%ou                             Choctawhatc6e Bay                             30        24-70                 86      29-55
                   CBSP                         Shirk Point                            Choctawhatchee Bay                            30        28-95                 86      2S-60
                   CBSR                         Off Saw-c ia Rosa'                     Choctawhatch" Bay                             30        23 50                 86      10-60
                   PCLO                         Little 0,-.ster Ba)-                   Panama City                                   30        15-00                 85      40-87
                   PCMPO                        Munmnaj Pier                           Panama City                                   30        08-20                 85      37-50
                   SAWB                         Watson' Bavou                          St. Andrew Bav                                30        0-850                 85         5 8
                   APDB                         Drv Bar                                Apalachicola liay                             29        41-50                 85      05-00
                   APCP                         Cai Point Bar                          Apalachicola Bay                              29        43-00                 84      52-50
                   AESP                         Spring Creek                           Apalachee Bay                                 30        30-30                 94      19 38
                   CKBP                         Black Point                            Cedar Key                                     29        10-25                 83      03-00
                   TBNP                         Navar:z Park                           Tampa Bay                                     27        48-30                 82      4528
                   TBMK                         Mullet Key Bayou                       Tampa Bay                                     27        37-17                 82      43-62
                   TBPB                         Papys Bay-pu                           Tampa Bay                                     27        50-72                 82      36-75
                   TBOT                         Old Tampa Bay                          Tampa Bay                                     28        01-48                 92      37-95
                   TBKA@                        K. Airport                             Tampa Bay                                     27        54-46                 82      27-29
                   TRCB                         Cockroach Bay                          Tampa Bay                                     28        40-55                 82      30-56
                   CBB1                         Bird Island                            Charlotte Harbor                              26        31@00                 82      02-60
                   CBFM1                        Fort %levers                           Charlotte Harbor                              26        38-64                 81      52-48
                   NBNB                         Nap)-- Ba%                             Naples Bay                                    26        00-00                 81      32-00
                   RBHC'                        Hend-son Crock                         Rookerv gav                                   26        01-83                 81      43-75
                   EVFU                         Faka 1:nion Bay                        Everglades                                    25        54-27                 81      30-60
                   BHKF'
                   Sites that were not sampled coniccutively from 1989 to 1991.                              1-100






                                        Butyltin concentrations in oystersfrom the Gulf of Mexico                            105

           spiked will a urro,ale standard, extracted will 0*1%         14,5 ï¿½ 5,11 for DBT; and 11*1    1*5 for MBT, Method-
           tropolone in methylene chloride, hexylated, purified by      detection limit (MDL) on average was 5 ng Sn/g for
           using Si/Al columns, and analyzed by gas chromatog-          TBT and DBT and 10 ng Sn/g for MBT.
           raphy with a tin-selective-flame photometric detector.
           Quality control consisted in using duplicate samples,        RESULT'S AND DISCUSSION
           procedural blanks, and spike blanks. Quadruplicate
           analysis of one sample yielded the following means           Annual variation of butyltins at individual sites
           and standard deviations 395     14.5 ng Sn/g for TBT;        Oyster butyltin concentrations determined in 1989,


                                                        Tributyltin    (ng Sn/g)
                                                     1-6-19-89  13 1990      1991


                             low -


                             600-


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                                                               SITE
           Fig. 1. Geographical distribution of tributyltin concentrations in oysters (Crassostrea virginica) from tl@e Gulf of Mexico coast.
                                   Asterisks indicate those sites which were not sampled in consecutive years.


                                                                            1-101














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              108                            B. Garcia-Romero, T L. Wade, G. G. Salata, J. M. Brooks

              Of a dynamic equilibrium between uptake, metabolism,             in 1989, 1990, and 1991,    respectively. Generally, sites
              and depuration.                                                  with high TBT concentrations had high MBT concen-
                 The TBT concentrations determined for each site               trations. MBT was detected in 21, four, and nineteen of
              during 1989, 1990, and 1991 are shown in Fig. 1. Sites           the 53 sites during 1989, 1990, and 1991, respectively.
              are shown in geographical order from Texas to                    During all three years, MBT was detected at only three
              Florida. Tributyltin concentrations ranged from <5 ng            sites in Florida (CBJB, TBKA and CBFM) and at one
              Sn/g to 1450 (TBKA), 770 (BBMB), and 1160 ng Sn/g                site in Texas (CCIC). The fact that MBT was found in
              (BBMB) in 1989, 1990, and 1991, respectively. TBT                lower concentrations than DBT and DBT was found in
              concentrations increase monotonically at some sites              lower concentrations than TBT is consistent with the
              from 1989 to 1991, whereas, at other sites, concentra-           fact that TBT is the major constituent of anti-fouling
              tions decreased monotonically. For example, oyster               paints, while DBT and MBT are environmental-break-
              TBT concentrations increased from 1989 to 1991 at                down products of TBT. This may indicate that only a
              CLLC, BBMB, and GBTD (Fig. 1). Decreasing TBT                    limited degradation of TBT has occurred or that the
              concentrations from 1989 to 1991 were observed for               more water-soluble DBT and MBT were assimilated by
              oysters from PBPH, SAWB, TBCB, MBLR, and MBEM                    the oysters at a slower rate than TBT.
              (Fig. 1). Concentrations of TBT were the same at
              TBOT and GBCR during all three years. In general,                Annual variation of butyltins in the Gulf of Mexico
              higher concentrations of TBT were determined in                  A graphic representation of the TBT data for the 53
              Florida sites than in Texas, Louisiana, Mississippi. or          sites sampled in 1989, 1990, and 1991 is shown in
              Alabama sites. TBT was below the detection limit                 Fig. 4. The graph is a plot of 1989 concentrations
              at one of 53 sites in 1989 and at ten and eleven                 against those of 1990 and 1991. The x and Y scales are
              sites during 1990 and 1991, respectively. Although the           identical. If no change occurs in the TBT concentration
              concentrations were low, butyltins were detected in              at a site, those data will be plotted on the center line.
              oysters from every site sampledin at least one sampling          Sites that fall below the line show a decrease, whereas
              year.                                                            points that rise above the line show an increase com-
                Dibutyltin concentrations determined in oysters during         pared with 1989. Two other lines also appear in Fig. 4.
              1989, 1990, and 1991 are shown in Fig. 2. Dibutyltin             These are the fines that form the boundary of sites with
              concentrations ranged from <5 ng Sn/g to 380 (TBKA)@             a factor of two increase (top line) or decrease (bottom
              160 (TBKA), and 200 ng Sn/g (TBKA), in 1989, 1990,               line). Only six sites for 1990 and eight for 1991 of the
              and 1991, respectively. Sites sampled in Florida had the         53 sites plotted for each year are above the center line.
              highest DBT concentrations. With the exception of five           Hence, over 85% of the TBT concentrations in 1990
              sites (CBJB. TBKA. CBFM, BBMB, and BRFS), the                    and 1991 were less than the concentration measured in
              annual variation of DBT concentrations did not mimic             oysters, at that site in 1989. There were 30 sites (57%) in
              the annual variation of TBT concentrations. Ship and             1990 and 20 sites (38%) in 1991 that had decreases, of
              boating activities have been cited as potential factors          more than a factor of two. There was only one site that
              that may affect DBT fluctuations (Short and Sharp,               had an increase of TBT concentration of more than a
              1989; Uhler et aL, 1989). Furthermore, the commercial            factor of two.
              usage of DBT as a stabilizer for plastics, including               In order to detect temporal trends, the butyltin
              PVC pipes, may be another important source of input              oyster concentrations for the entire Gulf of Mexico
              to the marine environment and may result in DBT                  from 1989 to 1991 are compared. Annual variations of
              fluctuations that do not mimic TBT fluctuations (Fent            butyltins for the entire Gulf of Mexico are not readily
              et aL, 1991: Maguire, 1991). At this point, it is not            apparent in Figs. 1, 2, or 3, where only annual concen-
              possible to estimate the influence of the factors dis-           trations at'individual sites are compared. Comparisons
              cussed above on the.DBT concentrations present in the            of arithmetic mean, geometric mean.. and medians
              oysters. Monotonic increases or decreases of DBT were            (Table 2) for butyltin concentrations determined during
              observed at specific sites during the three-year period.         1989, 1990, and 1991 are based only on the 53 sites that
              For example, Middle Bank (BBMB, Figs I and 2) not                were sampled in all three years. All these parameters
              only showed. increasing concentrations of TBT during             were calculated by assigning 5 ng Sn/g to all those
              the three-year sampling period but also showed a                 samples with concentrations below the limit of detec-
              steady increase in DBT in the sample period. DBT was             tion. The percentage of samples below the detection
              detected in 39, 38, and 33 out of the 53 sites sampled in        limit is listed in Table 2. The median and geometric
              each of the three years. In many instances, DBT was              means are similar in all cases, whereas the arithmetic
              not detected in any of the sampling years.                       mean is always higher. The median or the geometric
                Regional MBT concentrations are shown in Fig, 3.               mean appears to be the better estimator of the central
              Since the MBT concentrations are low, annual varia-              tendency of the data. On the basis of the median or the
              tions in MBT concentrations for each site are large.             geometric mean, there was a decrease in TBT oyster
              The precision of MBT determination is also not as                concentrations when 1989 is compared with 1990 or
              good as that of TBT and DBT (Wade et aL, 1988).                  1991.
              Monobut-0tin concentrations ranged from <5 ng Sn/                  A complete view of butyltin' concentrations for the
                                                                        9
              to 145 (NBNB), 25 (CCIC), and 42 ng Sn/g (TBKA).                 whole Gulf of Mexico for a given year can be achieved


                                                                                1-104






                                              Butyllin concentrations in oystersfrom the Gutf of Mexico                                     109


                                       10000-.

                                                      GULY COAST OYSTERS



                                        1000".





                                          100






                                            10
                                                                      M 0 91: Wom




                                                 1                10               100              low              10"

                                                                   TBT (ng Sn/g) 1989

             Fig. 4. Tributyltin concentrations determined in 1989 plotted against the tributyltin concentrations determined in 1990 and 1991.
             Points falling along the oenter line have equal concentrations, colateral lines indicate a factor of two greater or less than the con-
                                                             centrations determined in 1989.

             by using either cumulative-percentage-distribution or                (Fig. 5) are Gaussian with some degree of skewness.
             probability-distribution curves (Mackay & Paterson.                  DBT had a log-normal distribution only in 1989 and
             1984; O'Connor & Ehler, 1990; Jackson et at, in the                  1990, whereas MBT does not follow a log-normal dis-
             press). Although both types of curve may describe a                  tribution for any of the years. The geometric mean
             distribution of butyltin concentration for each year,                concentrations are indicated by solid lines for 1989,
             probability-distribution curves were chosen because                  dotted lines for 1990, and dashed lines for 1991 (Fig. 5)
             they are more easily compared, Use of this type of                   and are also reported in Table 2a, The TBT, DBT, and
             curve assumes that the log of the concentration pro-                 MBT concentrations for ï¿½ I standard deviation from
             duces a normal distribution. Log-normal distributions                the geometric mean are listed in Table 2b. Probability-
             have already been reported for environmental data                    distribution curves of TBT in oysters from the Gulf
             obtained in the NOAA National Status and Trends                      of Mexico provide information about annual variations
             Mussel Watch Program (O'Connor & Ehler, 1990;                        at low, medium, and high ranges of concentration.
             Jackson er at, in the press).                                        Although the standard deviations quantify the spread
                TBT log (distribution) curves are shown in Fig. 5 for             of a data set, they provide no information about how
             1989, 1990, and 1991. These curves were obtained by                  low or high concentrations changed with time. The
             using the following equation (Milton & Arnold, 1986):                TBT concentration decreased from 1989 to 1990 at all
                    f(x) = js[4(27r)])-' exp - 10.5[(x - A)lsf)          (1)      concentrations, whereas it decreased from 1989 to 1991
                                                                                  at low and medium concentrations but was similar for
             where f(x) is the distribution probability of the           log      the two years at high concentrations (Fig. 5). This de-
             (butyltin concentration), s is the standard deviation, x             crease may be the result of the TBT regulation of 1988
             is the log of the butyltin concentration, and X is the               and/or development and use of lower-rciease-rate TBT
             geometrical mean. Each f(x) was then divided by the                  paint formulations. Initial TBT regulations probably
             sum of the f(x) values shown by eqn (2):                             resulted in a marked reduction in private boat owners
                                                                                  painting their own vessels. The facts that newer TBT-
                                r(x)i = fwily. RX)i                      (2)
                                                                                  containing pamts are rated to be good for up to five
             in such a way that                                                   years and that TBT was not banned but its use limited
                                                                                  probably lead to decreased TBT inputs. This may have
                                        Nx)i                             (3)      resulted in the observed decreases in TBT concentra-
               TBT-concentration curves from 1989, 1990, and 1991                 tions in 1990 and 1991. The decrease observed at high
                                                           1991




































































                                                                                   1-105






                110                                 B.  Garcia-Romero, T L.         Wade, G. G. Salata. J. M. Brooks

                         0.03-                                                                                       -0--        1989
                                                                                                                      --(>,- 1990
                                                                         A   :   :                                                                                                      I
                                                                                                                         'dr     1991


                                                                 AA
                         0.02-




                                                      A

                         0.01-






                         0.00                                                                                                                       H
                                 1                             10                         100                         1000                        10wo
                                                                              TBT (ng Sn/g)
                           Fig. 5.  Log-normal distribution of tributyltin concentrations determined in oysters in 1989, 1990, and 1991.

                concentrations from 1989 to 1990 but not in 1991 may                        chanees in TBT-based paint formulations, but the
                be due to the naturally higher variation of TBT con-                        effects are not as apparent at sites with high TBT
                centrations near input areas (Seligman et aL, 1988).                        concentrations. Distribution curves for DBT and
                TBT lower-concentration ranges may therefore have                           MBT concentrations did not follow a log-normal
                decreased as a consequence of TBT regulations or                            distribution but also showed annual variations. This
                Table 2a. Arithmetic and geometric means and medians                        may be due to the high percentage of values below
                                           (ng Sat),                                        the MDL (Table 2).
                                             TBT               DBT        MBT               CONCLUSION
                1989                                                                        Oysters are valuable biomonitors for butyltins. The
                 Arithmetic mean             176               32         13                percentage of TBT present with respect to the total
                 Geometric mean               85               14            8
                 Median                       77(2%)           12(26%)       5(60-/.)       butyltins oscillated around 85% during the three years
                1990                                                                        sampled. There was a decrease in the butyltin concen-
                 Arithmetic mean              96               17            6              tration from 1989 to 1990 or 1991. However, at high
                 Geometric mean               30               8             6              concentrations. there was little difference between 1989
                 Median                       24(17%)          5 (72%)       5(90-1.)
                1991                                                                        and 1991. Environmental response to the TBT regula-
                 Arithmetic mean             150               25            8              tion in 1988 is not yet apparent. The decline between
                 Geometric mean               43               13            6              1989 and 1990 or 1991 may have resulted from pre-
                 Median                       42(17%)          8(40-/.)      5(66%)         vious chanLyes in anti-fouling paint formulation with
                 Numbers in parenthesis indicate percentage              of  samples        lower TBT-release rates or the suspension of painting
                below MDL.                                                                  activities by individual boat owners after 1988. Because
                                                                                            the newer TBT paints were formulated to last five years
                Table 2b. Geometric mean ï¿½1 standard deTiation            of the log        or more, there are many boats still in use that were
                             (butyltin concentrations) (ng Sn/g)                            painted with TBT-containing paints before the ban.
                                             TBT               DBT        MBT               Consequently. continuous monitoring is necessary to
                                                                                            determine trends in butyltin contamination of the
                1989                                                                        marine environment.
                 Plus                        29i               44         18
                 Minus                        25               5             3
                1990                                                                        ACKINOWLEDGENIENT
                 Plus                        141               21            8
                 Minus                          6              3             4              This research was supported by the National Oceanic
                1991                                                                        and Atmospheric Administration Grant No. 50-DGNC-
                 Plus                        233               37         10                5-00262 (National Status and Trends Mussel Watch
                 Minus                          8              4             4              Program).


                                                                                             1-106







                                               Buyltin concentrations in oyster from the Gulf of Mexico

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                                                                                       1196-201.
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           Fent, K.. Hunn. J., Renggli, D. & Siegrist. H. (1991). Fate of              dation of tributyltin in San Diego Bay, California. waters.
              tributyltin in sewage sludge treatment. Mar. Environ. Res.,              Environ. Sci.Technol., 20. 1229-35.     '
              32,223-31.                                                            Seligman, P. F., Valkirs. A. 0. & Lee, R. F. (1986a). Degra-
           GERG (1991). NOAA Status and Trends, Mussel Watch                           dation, of tributyltin in marine and estuarine waters. In
              Program. Field Sampling and logistics. Year VI. The                      Proceedings of the Oceans '86 Organoiin Symposium. Vol.
              Geochemical and Environmental Research Group, Texas                      4, pp. 1189-95.
              A&M Research Foundation. Technical Report 91-046. US                 Seligman, P. F., Valkirs. A. 0., Stang, P. M. & Lee. R. F.
              Department of Commerce, National Oceanic and Atmo-                       (1988). Evidence for rapid degradation of tributyltin in a
              spheric Administration. Ocean Assessment Division.                       ma
           Hall, L. W., Jr. & Pinkney, A. E. (1985). Acute and sublethal                  rine. Mar. Pollut. Bull., 19, 531-4.
              effects of organotin compounds on aquatic biota: An inter-            Short, J. W. & Thrower, F. P.(1986). Tri-n-butyltin caused
              pretative literature evaluation, CRC Critical Reviews in                 mortality of chinook salmon, Oncorhynchus ishawyicha. on
              Toxicology. 14, 159-209.                                                 transfer to TBT-treated marine net pen. In Proceedings of
           Huggett. R.J., Unger, M. A., Seligman, P.F. & Valkirs. A.                 the Oceans '86 Organotin Symposium. Vol. 4, pp. 1202-5.
              0. (1992). The marine biocide tributyltin. Assessing and              Short, J. W. & Sharp, J. L. (1989). Tributyltin in bay mussels
              managing the environmental risks. Environ. Sci. Technol..                (Mytilus edulic) of the Pacific Coast of the United States.
              26. 232-7.                                                               Environ. Sci. Technol.. 23. 740-3.
           Jackson. T. J.. Wade, T. L., McDonald, T. J., Wilkinson, D.              Thain, J. E. (1986). Toxicity of TBT to bivalves: Effects on
              L & Brooks. J.M. (Submitted) Polyaromatic hydrocarbon                  reproduction, growth and survival. In Proceedings of the
              contaminants in National Status and Trends oysters from                  Oceans '86 Organozin Symposium, Vol. 4. pp. 1306-13.
              the Gulf of Mexico (1986-1990). Oil Chem. Poll., sub-                 Thompson, J. A. J.. Sheffer. M. G.. Pierce. R. C.. Chau. Y.
              mitted for publication.                                                  K., Cooney. J. J.. Cullen. W. R. & Maguire, R. J. (1985).
           Langston, W. J. & Burt, G. R. (1991). Bioavailability and                   Organotin Compounds in the Aquatic Environment:
              effects of sediment-bound TBT in deposit-feeding clams.                  Scientific Criteria for Assessing their Effects on Environmen-
              Scrobicularia plana. Mar. Environ. Res.. 32. 61-77.                       tal Quality. National Research Council of Canada (NRCC
           Laughlin. R. B.. French, W. & Guard. H. E. (1986). Accu-                    Associate Committee on Scientific Criteria for Environ-
              mulation of bis(tributyltin) oxide by the marine mussel                  mental Quality).
              mytilus edulis. Environ. Sci. Technol., 20. 884-90.                 Uhler, A. D..Coogan, T. H.. Davis, K. S., Durell. G. S..
           Lee., R. F. (1985). Metabolism of tributyltin oxide by crabs,               Steinhauer, W. G.. Freitas. S. Y. & Boehm. P. D. (1989).
              oysters and fish. Mar. Environ. Res.. 17, 145-8.                         Findings of tributyltin in bivalves from selected U.S.
           Lee, R. F.. Valkirs, A. 0. & Seligman, P. F. (1987). Fate of                coastal waters. Environ. Toxicol. Chem.. 8. 971-9.
              tributyltin in estuarine waters. In Proceedings of the Oceans         Valkirs, A.0.. Davidson, B.. Kear. L. L.. Fransham. R. L..
              '87 International Organotin Symposium, Vol. 4, pp.                       Grovhoug, J. G. & Seligman. P. F. (1991). Long-term
              1411-15.                                                                 monitoring of tributyltin in San Diego Bay California.
           Lee, R. F. (1991). Metabolism of tributyltin by marine                      Mar. Environ. Res., 32, 151-67.
              animals and possible linkages to effects. Mar. Environ.               Wade, T. L. & Garcia-Romero. B. (1989). Status and trends
              Res.. 32. 29-35.                                                         of tributyltin contamination of oysters and sediments from
           Mackay. D. & Paterson, S. (1984). Spatial concentration dis-                the Gulf of Mexico. In Proceedings of the Oceans '89
              tributions. Environ. Sci. Technol.. 18. 207A-14A.                        Organotin Symposium, Vol. 2, pp. 550-3.
           Maguire. R. J. (1991). Aquatic environmental aspects of non-             Wade, T. L., Garcia-Romero, B. & Brooks. J. M. (1988).
              pesicidal organotin compounds. Water Pollut. Res. J.                    Tributyltin contamination in bivalves from US coastal
              Canada, 26, 243-360.                                                     estuaries, Environ. Sci. Technol.. 22, 1488-92.
           Milton. J. S. & Arnold, (1986). Probabilit and Statistics       Wade, T.L., Garcia-Romero, B. & Brooks. J. M. (1991).
              in the Engineering and Computing Sciences. McGraw-Hill,                  Bioavailability of Butyltins. In Organic Geochemistry:
              New York& Toronto.                                                       Advances and Applications in the Natural Environment,
           Minchin, D., Duggan, C. B.,& King, W. (1987). Possible                      ed. D. A. C. Manning. Manchester University Press.
              effects of organotins on scallop recruitment. Mar. Pollut.               Manchester, U K, pp. 571-3.
              Bull., 18, 604-8.                                                     Wade, T. L., Garcia-Romero, B. & Brooks, J. M. (1991b).
           O'Connor. T. P. & Ehler, C. N. (1990). Results for the                      Oysters as biomonitors of butyltins in the Gulf of Mexico.
              NOAA National Status and Trends Program on distribu-                     Mar. Environ. Res 32, 233-42.
              tion and effects of chemical contamination in the coastal             Waite, M. E., Waldock, M. J.. Thain. J. E., Smith, D. J. &
              and estuarine United States. Environ. Monitor. Assessment,               Milton. S. M. (1991). Reductions in TBT concentrations in
              16, 1-17.                                                                UK estuaries following legislation in 1986 and 1987. Mar.
           Olson, G. J. & Brinckman, F. E. (1986), Biodegradation of                   Environ.rs.. 32.89-111
           tributyltin by Chesapeake Bay microorganisms. Proceed-


                                                         1-107



















                           Reprint I I

          The American Oyster (Crassostrea virginica)
               as a Bioindicator of Trace Organic
                         Contamination



                        Jos6 L. Sericano






















                              1-109














                    THE AMERICAN OYSTER (CRASSOSTREA VIRGINICA) AS A BIOINDICATOR

                                      OF TRACE ORGANIC CONTAMINATION






                                                   A Dissertation


                                                       by

                                              JOSE LUIS SERICANO






                                     Submitted to the Office of Graduate Studies of
                                               Texas A&M University
                                  in partial fulfillment of the requirement for the degree of

                                            DOCTOR OF PHILOSOPHY








                                                    May 103






                                            Major Subject: Oceanography
















                    THE AMERICAN OYSTER (CRASSOSTREA VIRGINICA) AS A BIOINDICATOR

                                    OF TRACE ORGANIC CONTAMINATION






                                                 A Dissertation

                                                      by

                                             JOSE LUIS SERICANO








                   Ap o     as to style and content by:
                          I - - X, /,r,@ IL
                          james'M. Bi6oks                            Teriy L. Wade
                            hair of Committee)                   (Co-Chair of Committee)



                                                                    15obby J. PreiWey
                             (W@ber)                                   (Member)


                          Ste*n H. Safe                              Samily M. Ray
                            ((Member)                                  (Member)



                          Gilbert T. Rowe
                        (Head of Department)



                                                   May 1993


















                                                             ABSTRACT



                                    The American Oyster (Crassostrea virginica) as a Bioindicator of

                                              Trace Organic Contamination. (May 1993)

                                                         Josd Luis Sericano,

                                          Qufmico, Universidad Nacional del Sur, Argentina;

                                     Lic. en Bioqufmica, Universidad Nacional del Sur, Argentina;

                                       Lic. en Qui'mica, Universidad Nacional del Sur, Argentina;

                                                M.S., Texas A&M University, U.S.A.

                                      Co-Chairs of Advisory Comn-dttee: Dr. James M. Brooks
                                                                          Dr. Terry L. Wade




                            This study was designed to examine the uptake and depuration of trace organic

                        contaminants, e.g. polynuclear aromatic hydrocarbons (PAHs), polychlorinated

                        biphenyls (PCBs), including planar congeners, and butyltin species, by oysters

                        (Crassostrea virginica) through transplantation experiments in Galveston Bay, Texas.

                            PAHs, low molecular weight PCBs and tributyltin (TBT) were rapidly

                        bioaccumulated by transplanted oysters and apparent equilibrium concentrations were

                        reached after 20 to 30 days of r@xposure. In contrast, high molecular weight PCBs did

                        not reached an equilibrium plateau at the end of the seven-week exposure period. When

                        oysters'were back-transplanted to their former location, PAHs, low molecular weight

                        PCB congeners and TBT were depurated at similar rates while the high molecular,
                        weight PCBs were depurated at considerably slower rates. The original background






                                                                                                                  iv



                         concentrations were not reached after the 50-day depuration period. Chronically

                         contaminated Ship Channel oysters, simultaneously transplanted to the uncontaminated

                         area, showed lower clearance rates than those encountered for originally

                         uncontaminated bivalves.

                             Oysters exposed in the laboratory to PCBs and PAHs, preferentially bioaccumulated

                         four to six chlorine-substituted PCBs and four- and five-ring PAHs. Oysters exposed

                         simultaneously to PAHs plus PCBs depurated PAHs at a faster Tate than oysters that

                         were exposed solely to PAHs. The half-lives for individual PAHs encountered in the

                         first group of oysters were similar to those found in the field.

                            The present study presents evidence to substantiate the theory that bioconcentration

                         and clearance of different PCB congeners by oysters appear to be more affected by

                         molecular size than by hydrophobicity. The influence of the chlorine substitution

                         patterns in the bioaccumulation of PCBs by oysters is particularly evident in the case of

                         the highly toxic planar congeners.

                            Indigenous oysters can be valuable bioindicators of environmental contamination by

                         trace organic compounds paly if their limitations are fully understood. Within these

                         limitations, transplanted oysters can be succesfully used to monitor environmental

                         contamination by PAHs and TBTs in areas lacking indigenous bivalves if deployed in-

                         situ for a period of time of at least 30 days; for PCBs, however, a much longer time

                         period, Le over 6 months, may be required.







                                                                                                                    v










                                                         ACKNOWLEDGEMENTS



                              I would like to express my sincere gratitude to the co-chairmen of my Graduate

                          Committee Dr. James M. Brooks and Dr. Terry L. Wade for lending support and advice

                          during the preparation of this dissertation. I am also grateful to Dr. Eric N. Powell, Dr.

                          Bobby J. Presley, Dr. Stephen H. Safe and Dr. Sammy M. Ray for their assistance and
                          helpful suggestions as members of my Graduate Committee. I thank Dr. Don E.

                          Albrecht who served as the Graduate College Representative.

                              My deepest gratitude is expressed to Dr. Elliot L. Atlas who got me started in the

                          analysis of polychlorinated biphenyl by high-resolution gas chromatography. I also

                          acknowledge Dr. Roger R. Fay for allowing me to use the boats everytime that I needed

                          to do the samplings and sincerely appreciate Ken McCormick's generous help during

                          these activities. I thank Mrs. Amani M. El Husseini for helping me to develop the

                          carbon:silica column chromatographic technique used during this study. I am truly

                          indebted to Dr. Thomas J. McDonald and Mr. Bernardo Garcfa-Romero for the

                          analyses of polynuclear aromatic hydrocarbons and butyltins, respectively. Thanks also

                          goes to Dr. Thomas J. Jackson for helpful suggestions while preparing this manuscript.

                          Thanks to everyone at GERG for their friendship.

                             Finally, I would like to thank my wife, Ndlida, for her love, understanding and

                          constant support throughout my college career and apologize to my son, Mauro, and

                          daughter, Gisella, for the many weekends lost to this project.







                                                                                                                                                     vi










                                                                           TABLE OF CONTENTS



                                                                                                                                                Page
                                  ABSTRACT           ................................................................................              iii

                                  ACKNOWLEDGEMENTS                      ...............................................................             v

                                  TABLE OF CONTENTS                        ..................................................................      vi

                                  LIST OF TABLES           .........................................................................               xi

                                  LIST OF FIGURES              ........................................................................           X111

                                  CHAPTER

                                       I         INTRODUCTION              ............................................................             I
                                                      Statement of Purpose          ....................................................            I
                                                      Research Objectives         ......................................................            5
                                                      Galveston Bay System                  ...................................................     7


                                       11        BIOAVAILABILITY OF PAHs TO THE AMERICAN OYSTER
                                                 (CRASSOSTREA VIRGIMCA): AFIELD STUDY                                    ...................       10

                                                      Introduction      ...............................................................            10

                                                      PAHs: A Review           ........................................................            I I
                                                           Background Information            ............................................          I I
                                                           Distribution and Occurrence in Galveston Bay                  ...................       14
                                                           Bivalve Uptake and Depuration Studies                      ...........................  20
                                                      Uptake and Depuration of PAHs               .......................................          22
                                                           Experimental Design, Sample Collection and Methods                       .........      22
                                                                Extraction and fractionation of PAHs              .........................        24
                                                                Instrumental analysis             ............................................     28
                                                                Ancillary parameters               ............................................    28
                                                                Statistical analysis      ...............................................          29
                                                           Uptake of PAHs by Transplanted Oysters                  ........................        29







                                                                                                                                                      vii








                                    CHAPTER                                                                                                      Page
                                                            Depuration of PAHs by Newly and Chronically
                                                            Contaminated Oysters          ...............................................          39
                                                       Concluding Remarks                 .....................................................    45

                                        III       UPTAKE, RETENTION AND RELEASE OF PCBs BY THE
                                                  AMERICAN OYSTER (CRASSOSTREA VIRGINICA                                      ...............      48

                                                       Introduction      ...............................................................           48

                                                       PCBs:         A Review          .........................................................   49
                                                            Background Information           ............................................          49
                                                            Distribution and Occurrence in Galveston Bay                 ...................       53
                                                            Bivalve Uptake and Depuration Studies                     ...........................  56
                                                       Uptake and Depuration of PCBs               .......................................         58
                                                            Experimental Design, Sample Collection and Methods                       .........     58
                                                                 Extraction and sample fractionation of PCBs                 ................      58
                                                                 Instrumental analysis             ............................................    58
                                                                 Ancillary parameters        ............................................          60
                                                                 Statistical analysis     ...............................................          60
                                                            Uptake of PCBs by Transplanted Oysters                  ........................       60
                                                            Depuration of PCBs by Newly and Chronically
                                                            Contaminated Oysters          ................................................         70
                                                       Concluding Remarks                 .....................................................    76

                                        IV        UPTAKE AND DEPURATION OF PLANAR PCB CONGENERS
                                                  BY THE AMERICAN OYSTER (CRASSOSTREA VIRGMCA):
                                                  A SPECIAL"CASE OF PCBs                  ...............................................          80

                                                       Introduction      ...............................................................           80
                                                       Planar PCBs: A Review              .................................................        81
                                                            Background Information           ............................................          81
                                                            Distribution and Occurrence in Galveston Bay                 ...................       83
                                                            Bivalve Uptake and Depuration Studies                     ...........................  84
                                                       Uptake and Depuration of Planar PCBs                 ...............................        85






                                                                                                                                                   Viii









                                  CHAPTER                                                                                                      Page
                                                          Experimental Design, Sample Collection and Methods                       .........     85
                                                               Extraction and initial sample fi-actionation            ....................      85
                                                               Isolation of planar PCB congeners              ............................       85
                                                               Instrumental analysis             ............................................    86
                                                          Planar PCB Congener Analysis               ....................................        86
                                                          Uptake of Planar PCBs by Transplanted Oysters                    ................      90
                                                          Depuration of Planar PCBs by Newly Contaminated Oysters..                              95
                                                     Concluding Remarks                .....................................................     96

                                      V         UPTAKE AND DEPURATION OF TRIBUTYLTIN BY THE
                                                AMERICAN OYSTER (CRASSOSTREA VIRGINICA                                       ...............     97

                                                     Introduction      ...............................................................           97

                                                     TBT: A Review           ..........................................................          97
                                                          Background Inforniation           ............................................         97
                                                          Distribution and Occurrence in Galveston Bay                  ...................      99
                                                          Bivalve Uptake and Depuration Studies                      ........................... 99
                                                     Uptake and Depuration of TBT              .........................................        101
                                                          Experimental Design, Sample Collection and Methods                       .........    101
                                                               Extraction and sample fractionation             ...........................      101
                                                               Instrumental analysis             ............................................   102
                                                               Ancillary parameters         .............................................       102
                                                               Statistical analysis      ...............................................        102
                                                          Uptake of TBT by Transplanted Oysters                       .......................... 102
                                                          Deepuration of TBT by Newly and Chronically
                                                          Contaminated Oysters           ...............................................        105
                                                     Concluding Remarks                .....................................................    106

                                      VI        MECHANISM OF THE UPTAKE AND RELEASE OF TRACE

                                                ORGANIC CONTAMINANTS BY THE AMERICAN OYSTER
                                                (CRASSOSTREA VIRGINICA                       ...........................................        107

                                                     Introduction      ...............................................................          107






                                                                                                                                                      ix








                                   CHAPTER                                                                                                       Page
                                                      Mechanisms of Bioconcentration               .......................................       108

                                                            Kinetics    ...............................................................          108
                                                                 Polynuclear aromatic hydrocarbons              ...........................      Ill
                                                                 Polychlorinated biphenyls          ......................................       116
                                                                 Tributyltin    ........................................................         120
                                                            The Octanol-to-Water Partition Coefficient               .......................     122
                                                            The Two-Compartment Model Approach                     .........................     125
                                                            Depuration versus Degradation                   ..................................... 127
                                                      Concluding Remarks                 .....................................................   128

                                       VII SIMULTANEOUS UPTAKE AND DEPURATION OF PAHs AND
                                                 PCBs BY THE AMERICAN OYSTER (CHASSOSTRE
                                                 YIRGINICA)               ..................................................................     130

                                                      Introduction     ........................                                                  130
                                                            Simultaneous Exposure to PAHs and PCBs: A Laboratory
                                                            Study    ..................................................................          131
                                                            Aquarium Exposure           .................................................        131
                                                                 Extraction, fractionation and instrumental analyses of
                                                                 PAHs and PCBs               .................................................   135
                                                            Polynuclear Aromatic Hydrocarbons                ..............................      135
                                                            Polychlorinated Biphenyls;          ..........................................       141
                                                            PAH-PCB Interactions           ..............................................        148
                                                      'Concluding Remarks                .....................................................   151

                                       VIII NOAAS NATIONAL STATUS AND MENDS "MUSSEL
                                                 WATCH" PROGRAM                  .......................................................         153

                                                      Introduction      ...............................................................          153
                                                      Polynuclear Aromatic Hydrocarbons                  ..................................      155
                                                      Polychlorinated Biphenyls            ..............................................        157
                                                            7,PCB Congeners/Total PCB Relationship                   .......................     161
                                                            Planar PCB Congeners                 ............................................... 168









                                                                                                                                       x








                             CHAPTER                                                                                              Page
                                                Butyltin Species     ..........................................................   177

                                  IX       SUMMARY AND PROSPECFIVES                      ......................................   182

                             REFERENCES           .............................................................................   187

                             APPENDIX         ..................................................................................  209

                             VITA    .........................................................................................    242







                                                                                                                                                xi










                                                                             LIST OF TABLES



                                  TABLE                                                                                                    Page

                                   1       Hydrocarbon Concentrations in Samples from the Galveston Bay Area.
                                           Except Where Indicated, Concentrations in Organisms Are Expressed in
                                           ng g- I on a Wet-Weight Basis. Concentrations in Sediment and Water
                                           Samples Are Expressed in ng g-I, on a Dry-Weight Basis, and in ng 1-1,
                                           Respectively. Ranges in Parenthesis             ...........................................          15

                                   2       Biological Half-Lives (Days) of PAHs in Hanna Reef and Ship Channel
                                           Crassostrea virginica Oysters          .....................................................         46

                                   3       Polychlorinated Biphenyl Concentrations in Samples from the Galveston.
                                           Bay Area. Except Where Indicated, Concentrations in Organisms Are
                                           Expressed in ng g- I on a Wet-Weight Basis. Concentrations in Sediment
                                           and Water Samples Are Expressed in ng g- 1, on a Dry-Weight Basis, and
                                           in ng 1-1, Respectively       ............................................................           54

                                   4       Biological Half-Lives (Days) of PCBs in Hanna Reef and Ship Channel
                                           Crassostrea virginica Oysters          ....................................................          77

                                   5       Recoveries of Four Planar PCB Congeners from Spiked Aroclor 1254
                                           and Dolphin Blubber Samples Using Activated Carbon:Silica Columns ...                                91

                                   6       TBT, DBT and MBT Concentrations (in ng Sn g-.1 on a Dry-Weight
                                           Basis) in Oyster and Sediment Samples from the Galveston Bay Area                       .....       100

                                   7       Estimated Days to 90% Uptake Equilibrium (t90%), Bioconcentration
                                           Factors (BCF), Depuration Rates (kd) and Biological Half-Lives (BHL)
                                           for PAHs and PCB Congeners              'in Hanna Reef and Ship Channel Oysters
                                           During the Field Studies        ..........................................................          112







                                                                                                                                         xii








                               TABLE                                                                                                Page

                                8       Characteristics of the Relationships Between log Kb and log Kow for
                                        Bioconcentration of Trace Organic Contaminants in Different Organisms .                        126

                                9       Biological Half-Lives of PAHs in Crassostrea virginica Oysters Exposed
                                        in the Laboratory to Particle-Associated PAHs; Alone (Aquarium C) and
                                        PAHs + PCBs (Aquarium D)            ....................................................       140

                               .10      Biological Half-Lives of PCBs in Crassostrea virginica Oysters Exposed
                                        in the Laboratory to Particle-Associated PCBs Alone (Aquarium B) and
                                        PCBs + PAHs (Aquarium D)            ....................................................       149

                                11      PCB Congeners/Total PCB Relationships in Gulf of Mexico Oyster
                                        Samples      .............................................................................     164

                                12      Planar and Total PCB Concentrations in Oysters (Crassostrea virginica)
                                        from Galveston and Tampa Bays                  ................................................ 170

                                13      2,3,7,8-TCDD Equivalents (pg g-1) Corresponding to Non-Ortho
                                        Substituted PCB in Oysters (Crassostrea virginica) from Galveston and
                                        Tampa Bays      ........................................................................       172

                                14      Selected Mono- and Di-Ortho Substituted PCB and Total PCB Average
                                        Concentrations (ng g-1) in Oysters (Crassostrea virginica) from
                                        Galveston and Tampa Bays           ......................................................      174

                                15      Average 2,3,7,8-TCDD Equivalents (pg g-1) Corresponding to Selected
                                        Mono- and Di-ortho Substituted PCBs in Oysters (Crassostrea virginica)
                                        from Galveston and Tampa Bays                  ................................................ 175







                                                                                                                                                 xiii











                                                                              LIST OF FIGURES



                                   FIGURE                                                                                                      Page

                                   I         Galveston Bay, Texas          ............................................................            8

                                   2         Structures and common names of selected aromatic hydrocarbons
                                             discussed in the text     ...............................................................           12


                                   3         Galveston Bay transplantation sites           .............................................         23

                                   4         Exposure (a) and depuration (b) sites, respectively. Approximately 250
                                             adult oysters (c) were transplanted in net bags (d)             ............................        25

                                   5         Trace organic analytical scheme           .................................................         26

                                   6         Concentrations of polynuclear aromatic hydrocarbons, grouped by
                                             number of rings, in transplanted Hanna Reef and indigenous Ship
                                             Channel oysters during the 48-day exposure period near the Houston
                                             Ship Channel. Ship Channel oysters were not sampled on day 7                        ..........      31

                                   7         Concentrations of selected polynuclear aromatic hydrocarbons in tissues
                                             of Hanna Reef and Ship Channel oysters during exposure to the Ship
                                             Channel area contaminant levels and following transplant to the Hanna
                                             Reef. area       ............................................................................       32


                                   8         Concentrations of individual polynuclear aromatic hydrocarbons in
                                             tissues of Hanna Reef and Ship Channel oysters at the end of the 48-day
                                             .exposure period          ....................................................................      36

                                   9         Concentrations of polynuclear aromatic hydrocarbons, grouped by
                                             number of rings and individually, in Ship Channel sediment sarnples                       ......    37






                                                                                                                                       xiv








                              FIGURE                                                                                                 Page

                              10       Concentrations of polynuclear aromatic hydrocarbons, grouped by
                                       number of rings and individually, in Ship Channel seawater samples                  ......      38

                              11       Concentrations of polynuclear aromatic hydrocarbons, grouped by
                                       number of rings, in back-transplanted Hanna Reef and transplanted Ship
                                       Channel oysters during the 50-day depuration period in the Hanna Reef
                                       area  ..................................................................................        40


                              12       Concentrations of individual polynuclear aromatic hydrocarbons in
                                       tissues of Hanna Reef and Ship Channel oysters at the end of the 50-day
                                       depuration period      ..................................................................       41

                              13       Comparison of the concentrations of polynuclear aromatic hydrocarbons,
                                       grouped by number of rings and individually, in tissues of Hanna Reef
                                       oysters before exposure to the Ship Channel contaminant levels and after
                                       depuration at the Hanna Reef site                 ................................................ 42

                              14       Concentrations of polynuclear aromatic hydrocarbons, grouped by
                                       number of rings and individually, in Hanna Reef sediment samples                    ........    44

                              15       General formula of polychlorinated biphenyls and examples of major
                                       congeners commonly found in environmental samples                  .......................      50

                              16       Examples of high-resolution gas chrornatograms of Hanna Reef oysters
                                       transplanted to the Ship Channel area during different stages of the 48-
                                       day exposure period. PCB congeners are numbered according to
                                       Bal1schmitter & Zell, 1980        ........................................................      61


                              17       Concentrations of polychlorinated biphenyl congeners, grouped by level
                                       of chlorination, in transplanted Hanna Reef and indigenous Ship Channel
                                       oysters during the 48-day exposure period near the Houston Ship
                                       Channel. Ship Channel Oysters were not sampled on day 7                   ................      62









                                                                                                                                                 xv








                                  FIGURE                                                                                                     Page

                                  18       Concentrations of selected polychlorinated biphenyl congeners in tissues
                                           of Hanna Reef and Ship Channel oysters during exposure to the Ship
                                           Channel area contaminant levels and following transplant to the Hanna
                                           Reef area         .............................................................................     64


                                  19       Concentrations of selected polychlorinated biphenyl congeners in tissues
                                           of Hanna Reef and Ship Channel oysters at the end of the 48-day
                                           exposure period            ....................................................................     67

                                  20       Percent differences in concentrations of selected polychlorinated
                                           biphenyls between Hanna Reef and Ship Channel oyster tissues at the end
                                           of the 48-day exposure period. Positive values indicate congeners with
                                           greater accumulation in Ship Channel oysters                .................................       69

                                  21       Concentrations of polychlorinated biphenyls, grouped by level of
                                           chlorination, in Ship Channel sediment and seawater samples                     ..............      71

                                  22       Concentrations of polychlorinated biphenyl congeners, grouped by level
                                           of chlorination, in back-transplanted Hanna Reef and transplanted Ship
                                           Channel oysters during the 50-day depuration period in the Hanna Reef
                                           area   ..................................................................................           73


                                  23       Concentrations of selected polychlorinated biphenyl congeners in tissues
                                           of Hanna Reef and Ship Channel oysters at the end of the 50-day
                                           depuration period      ... ..............................................................           74

                                  24       Comparison of the concentrations of selected polychlorinated biphenyl
                                           congeners measured in tissues of Hanna Reef oysters before-exposure to
                                           the Ship Channel contaminant levels and after deputation at the Hanna
                                           Reef site    ............................................................................           75






                                                                                                                                      xvi








                             FIGURE                                                                                                 Page

                             25        Concentrations of polychlorinated biphenyls, grouped by level of
                                       chlorination, in Hanna Reef sediment samples              ................................     78

                             26        General formula of polychlorinated biphenyls. Three of the most toxic
                                       planar PCB congeners, i.e. PCB 77, 126 and 169, are shown together
                                       with the compounds they mimic in toxic effects             ...............................     82

                             27        High-resolution gas chromatographic analyses of (a) Aroclor 1254 spiked
                                       with planar PCB congeners (i.e., 77, 81, 126 and 169), (b) PCB
                                       congeners recovered in Fraction 1, and (c) planar PCB congeners eluted
                                       in Fraction 2. PCB congeners 103 and 198 are external standards. PCB
                                       congeners are numbered according to Ballschrrdtter & Zell, 1980                 ..........     88

                             28        High-resolution gas chromatographic analyses of (a) dolphin blubber
                                       extract spiked with planar PCB congeners 77, 81, 126 and 169, (b)
                                       chlorinated hydrocarbons recovered in Fraction 1, and (c) planar PCB
                                       congeners eluted in Fraction 2. PCB congeners are numbered according
                                       to Ballschmitter & Zell, 1980        ....................................................      89


                             29        Example of high-resolution gas chromatograms obtained from an extract
                                       of indigenous Ship Channel oysters. PCB congeners are numbered
                                       according to Ballschmitter & Zell, 1980          ........................................      92

                             30        Concentrations of planar polychlorinated biphenyl congeners 77 and 126
                                       in tissues of Hanna Reef oysters during the uptake and depuration phases
                                       of the transplantation experiments at Galveston Bay             ..........................     94

                             31        Concentrations of tributyltin in tissues of Hanna Reef and Ship Channel
                                       Oysters during exposure to the Ship Channel area contaminant levels and
                                       following transplant to the Hanna Reef area            ...................................     104






                                                                                                                                        xvii







                                                                                                                                                         or-



                               FIGURE                                                                                                  Page

                               32        Depuration constant (kd) and biological lialf-lives (BHL) of planar PCB
                                         congeners compared to ranges of values calculated for non-plartar PCBs..                       117

                               33        Bioconcentration factors of six selected PCB congeners in relation to their
                                         liphophilicity and size     .............................................................      119

                               34        Relationship between chlorine-substitution patterns in PCBs and &@e_;r
                                         depuration half-lives. See text for explanation           ................................     121

                               35        Bioconcentration factors of polynuclear aromatic hydro@arbons and
                                         poIrchlorinated biphenyls calculated for transplanted Hanna Reef and
                                         indigenous Ship Channel oysters during the exposure period versus log
                                         octanol to water partition coe-fficients (I(o,,,)      ...................................     123

                               36        General laboratory set-up 'a), details of an aquarium and water
                                         recirculation system (b), dosing and feeding system (c), and oysters used
                                         during the experiment (d)               ......................................................... 133

                               37        Concentrations of selected polynuclear aromatic hydrocarbons in tissues
                                         of oysters during exposure to particle-associated PAHs alone (Aquariurn
                                         C) and PAHs + PCBs (Aquarium D) and following transplant to
                                         contaminant-free aquariums. Aquarium A was used as control                    .............    136

                               38        Concentrations of individual polynuclear aromatic hydrocarbons in
                                         tissues of laborutory expo      sed oysters after the 30-day exposure period to
                                         particle-associated PAHs (Aquarium C) and PAHs + PCBs (Aquarium
                                         D) .................................................................  * ....................   138

                               39        Concentrations of individual polynuclear                aromatic hydrocarbons ill
                                         tissues of oysters previously exposed in                the laboratory to particle-
                                         associated PAHs (Aquarium C) and PAHs + PCBs (Aquarium D) after
                                         the 30-day depuration period in contaminant-free aquarium,,;               ................    139






                                                                                                                                       xviii










                              FIGUREE                                                                                                Page

                              40        Concentrations of selected polychlorinated biphenyls in tissues of oysters
                                        during exposure to particle-associated PCBs alone (Aquarium B) and
                                        PCBs +* PAHs (Aqualium D) and following transplant to contaminant-
                                        free aquariums. Aquarium A was used as control                ............................     142

                              41        Comparison of the distribution of PCB congeners, grouped by level of
                                        chlorination, encountered in laboratory exposed oysters at the end of the
                                        30-day exposure period with that of the exposure mixture (i.e. 1:1:1:1
                                        Aroclor 1242, 1248, 1254 and 1260). Distribution of PCB congeners it]
                                        individual Aroclor mixtures are also shown                  .................................... 14.."t


                              42        Selective accumulation or depletion of PCB congeners in laboratory
                                        exposed oysters relative to the exposure Aroclor mixture              ....................     145

                              43        Concentrations of selected PCB congeners in tissues of laboratory
                                        exposed oysters after the 30-day exposure period to particle-associated
                                        PCBs (Aquarium B) and PC13s + PAIIs (Aquarium D)                    ......................     146

                              44        Concentrations of selected PCB congeners in tissues of oysters
                                        previously exposed in the laboratory to particle-associated PCBs
                                        (Aquarium B) and PCBs + PAHs (Aquarium D) after the 30-day
                                 -      depuration period in contaminant-free aquariums              ..............................    147

                              45        NOAA'    s National Status and Trends sampling locations in the Gulf of
                                        Mexico    ..............................................................................       154


                              46        Average distributions of PCB congeners                       grouped by level of
                                        chlorination, in Gulf of Mexico sediments and oysters              .......................     158

                              47        Average d.istributions of selected PCB congeners in Gulf of Mexico
                                        sedimens and oysters        ...............................................................    i60







                                                                                                                                           xix








                                 FIGURE                                                                                                Page

                                 48       Relationships between the sum of 18 selected PCB congeners and the
                                          total PCB load encountered in Gulf of Mexico oysters for the first year of
                                          NOAA's National Status and Trends Program. See text for discussion ...                         163

                                 49       Three different examples of the bias introduced in the report of total PCB
                                          concentrations by using the regression equation (see text) compared to the
                                          total PCB load calculated as the sum of all measurable individual,
                                          congeners       ...........................................................................    167

                                 50       NOAA's National Status and Trends sampling locations in Galveston and
                                          Tampa Bays       ........................................................................        169

                                 51       Toxic equivalents corresponding to three planar PCBs and selected mono-
                                          and di-ortho chlorine-substituted congeners in oyster samples collected
                                          from six different locations in Galveston and Tampa Bays                 ..................      176

                                 52       Contribution of planar and selected mono-ortho chlorine substituted PCB
                                          congeners to the total toxicity in oysters        ........................................       178


                                 53       Total butiltin concentrations at selected sites in the Gulf of Mexico
                                          sampled between 1986 and 1992 as part of NOAA's National Status and
                                          Trends Program        ...................................................................        180



















                                                             CHAPTERI




                                                           INTRODUCTION




                       STATEMENT OF PURPOSE



                          Many toxic organic compounds of both synthetic and natural origin, such as

                       polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs) and

                       butyltin compounds, e.g. tributyltin (TBT), can be present at high levels, i.e. ppm, in the

                       coastal marine environment (e.g. Kerkhoff er al., 1982; Malins er al., 1984, 1987; Wade

                       et al., 1988a) and may not only affect the productivity of marine organisms but may

                       ultimately be hazardous to human health.

                          PCBs and PAHs enter the marine environment from several sources including

                       precipitation, land runoff, atmospheric fallout, industrial and municipal was te discharge

                       and accidental spills (e.g. Hoffman et al., 1984; Prahl et al., 1984). PAHs are also

                       known to enter the marine environment from natural oil seepage (Venkatesan & Kaplan,

                       1982; Anderson et al., 1983; Kvenvolden & Harbough, 1983; Venkatesan et al., 1983).
                       The major source of tributyltin (TBT), the most toxic of the butyltin species (Davis &

                       Smith, 1980), to the marine environment is the use of antifouling paints containing this

                       compound.



                       7bis dissertation follows the format of the Marine Environmental Research journal.







                                                                                                                  2



                           Because of their low aqueous solubilities (e.g. Mackay et al., 1980; Whitehouse,

                        1984), PCBs, PAHs and butyltin compounds are rapidly adsorbed onto particulate matter,

                        which can result in their deposition with estuarine and coastal sediments (Herbes, 1977;

                        Pavlou & Dexter, 1979; Means et al., 1980; Langston et al., 1987). Sediments may serve

                        as a storage compartment for long-term release of contaminants by biogeochemical

                        processes (Sodergren & Larsson, 1982; Prahl & Carpenter, 1983; Coates & Elzerman,

                        1986; Unger et al., 19 87); however, the extent of residue accumulation in sediments is

                        largely determined by the chemical nature of the compounds and the sediment

                        characteristics, e.g. texture and organic matter content (Choi & Chen, 1976; Karickhoff et

                        al., 1979; Chiou et al., 1983; MacIntyre & Smith, 1984). Natural organic materials can

                        enhance the partition of hydrophobic compounds into the bottom sediments and pore
                        water (Brownawell & Farrington, 1985, 1986; Brownawell, 1986; Chin & Gschwend,

                        1992). This partition process influences the availability of PCBs, PAHs and butyltin

                        compounds to the overlying seawater and, in turn, to the aquatic organisms where these

                        compounds can accumulate by passive adsorption directly from water or by partitioning

                        into food. Both routes have been shown to contribute significantly to levels found in

                        fishes (Rubistein et al., 1984; Malins et al., 1987; Oliver & Niimi, 1983; Opperhuizen &

                        Schrap, 1988) and benthic organisms (Clement et al., 1980; Stekoll et al., 1980; Laughlin

                        er al., 1986; Salazar, 1986; Oliver, 1987).

                           A considerable body of knowledge exists on the dynamics of PCBs and PAHs uptake

                        and depuration in marine species (e.g., Stegeman & Teal, 1973; Lee, 1977; Clement et

                        al., 1980; Riley et al., 1981; Opperhuizen et al., 1985; Jovanovich & Marion, 1987;

                        Pruell et al., 1986, 1987; Tanabe et al., 1987a). Most of the previous studies, however,

                        described the steady-state bioconcentration factors of PCBs or PAHs by a variety of

                        marine organisms while only a few of them discussed the dynamics by which the final

                        levels are achieved. Until recently, investigations on PCBs and PAHs focused mainly on







                                                                                                                  3



                      the commercial Aroclor mixtures or whole petroleum (e.g. Stegeman & Teal, 1973;

                      Courtney & Denton, 1976; Shaw & Connell, 1982; Stickle et al., 1984) rather than on the

                      individual PCB congeners or specific PAHs (e.g. Duinker et al., 1983; Frank et al., 1986;

                      Pruell et al., 1986, 1987; Jovanovich & Marion, 1987; Tanabe et al., 1987a). Now, the

                      importance of considering individual compounds is well recognized in view of differences

                      in both toxicity (e.g. Safe, 1984, 1985, 1990; Tanabe et al., 1987b, 1987c) and

                      physicochemical properties controlling their assimilation by organisms (e.g. Shaw &

                      Connell, 1980, 1984; Opperhuizen er al., 1985, 1988). This is particularly important in

                      the case of planar PCB congeners (McFarland & Clarke, 1989). In a recent review on

                      PCBs, Oliver et al. (1989) described the current information on the behavior of individual

                      PCB congeners as limited; however, research on environmental pathways and hazard

                      assessments of specific congeners can be determined with the currently available analytical

                      procedures for PCBs. Similarly, Smith et al. (1990) stated that our understanding of the

                      hazards by PCBs to various animal species and ecosystems remains inadequate.

                      Moreover, little is known about the effects that a group of xenobiotic compounds, for

                      example PCBs, will have on the uptake and/or depuration dynamics of other

                      contaminants, for example PAHs. Interaction between PCBs and PAHs during uptake

                      has been reported to occur in fish and oysters (Stein et al., 1984; Collier et al., 1985;

                      Fortner & Sick, 1985).

                          Comparatively, the knowledge of the dynamics of butyltin compounds uptake and

                      depuration by different marine organisms is limited. Although contamination of the

                      coastal environment by TBT has been investigated since early 1980s, it was not until the

                      late 1980s that this compound was considered to be a real threat to the quality of coastal

                      waters.

                          Monitoring of PCBs, PAHs and butyltin compounds, at trace levels, in the aquatic

                      environment using various organisms is well-establi shed. Bivalves are generally








                                                                                                                  4



                       preferred for this purpose because of their wide geographic distribution, sedentary form

                       of life, ability to bioconcentrate organic and inorganic contaminants, comparatively low

                       enzyme activity for metabolizing xenobiotics, ability to survive under extreme pollution

                       conditions and commercial value (Goldberg et al., 1978; Bums & Smith, 1981;

                       Farrington et al., 1983). The use of bivalves as bioindicators has grown rapidly over the

                       last decade and the "Mussel Watch" concept is now being used by many national and

                       international programs (National Academy of Sciences, 1980; Farrington et al., 1983;

                       Risebrough et al., 1983; May-tin, 1985; Wade et al., 1988a, 1988b; Sericano et al., 1990a,

                       1990b, Tripp et al., 1992).

                           Laboratory experiments have been carried out in order to have a better understanding

                       of the uptake and depuration processes taking place in the environment; however,

                       extrapolations from laboratory tests to natural environmental conditions are not always

                       possible. For example, results of laboratory-based studies of PCB and PAH kinetics in

                       bivalves and field data revealed various inconsistencies, including which PCB isomers or

                       PAHs are preferentially accumulated and/or released by different bivalves and their half-

                       lives (e.g. Boehm & Quinn, 1976; Fucik & Neff, 1977; Jackim & Lake, 1978; Langston,

                       1978; Lee et al., 1978; Bjorseth er al., 1979; Calambokidis et al., 1979; Obana et al.,

                       1983; Pruell er al., 1986, 1987; Weigelt, 1986; Jovanovich & Marion, 1987; Tanabe et

                       al., 1987a; Fox, 1988; Wade et al., 1988c, Tanacredi & Cardenas, 1991). Although the

                       causes of such disagreements are not clear, the uptake of PCBs and PAHs from solution

                       in laboratory experiments may be different from real situations since the routes of

                       contaminant uptake may differ. Methods using contaminants adsorbed onto particles, e.g.

                       clay, might produce more realistic results in uptake/depuration studies since they closely

                       simulate the manner by which filter-feeding bivalves are likely to be exposed to organic

                       xenobiotics in the coastal marine environment. Also, the effects of using solubilizing

                       agents and exposure concentrations much higher than those measured in the field are







                                                                                                                 5



                      difficult to evaluate and extrapolate to real situations. In the case of experiments using

                      naturally contaminated sediments, synergistic or antagonistic effects between different
                      organic contaminants are likely to influence the uptake kinetics of these compounds.

                      Furthermore, certain techniques, such as breaking open the bivalve shell to permit

                      continuous contact with the contaminated medium (see, for example, Fortner & Sick,

                      1985), obviously produce conditions that are not normally encountered in the

                      environment.

                          Finally, marine organisms in the environment are exposed to complex contaminant

                      mixtures rather than to individual compounds. Therefore, detailed information on uptake

                      and deputation kinetics of xenobiotics for organisms exposed to contaminant mixtures

                      must include both field and laboratory studies to assess the effects of anthropogenic

                      chemicals on marine biota.




                      RESEARCH OBJECTIVES



                          In view of the preceding discussion, this study was designed to:
                          1. Evaluate the uptake of selected PCB congeners, PAHs and butyltin species in

                      transplanted American oysters, Crassostrea virginica, under field conditions in Galveston

                      Bay, Texas. Transplanted organisms from a clean environment, Hanna Reef, are

                      compared to native oysters from a chronically contaminated area near the Houston Ship

                      Channel where relatively high concentrations of PCBs, PAHs and organotin compounds

                      are known to exist. Body burdens of both oyster populations are compared to water and

                      sediment concentrations.

                          2. Evaluate the depuration of selected PCB congeners, PAHs and butyltin species in

                      newly and chronically contaminated American oysters, Crassostrea virginica, under field
                      conditions in Galveston Bay, Texas. As a continuation of the uptake experiment








                                                                                                                        6



                         mentioned above, both originally clean and chronically contaminated oysters were

                         transplanted from the area near the Houston Ship Channel to the Hanna Reef area and

                         their depuration kinetics were compared.

                             3. Evaluate the potential for highly toxic coplanar PCBs to bioaccumulate in oysters

                         under field conditions. Depuration rates of these PCB congeners by newly and

                         chronically contaminated individuals are compared.

                             4. Assess the usefulness of transplanted oysters in biomonitoring studies involving

                         these trace organic contaminants.

                             5. Compare, under laboratory conditions, accumulation and depuration dynamics of

                         selected individual PCB congeners and PAHs by the American oyster, Crassostrea

                         virginica, when simultaneously exposed to particle - associated PCBs, PAHs and PCBs

                         plus PAHs, at environmentally realistic levels.

                             6. Use the experimental results to better understand the PCB, PAH and butyltin data

                         in oyster samples collected along the northern Gulf of Mexico coast during the NOAA's

                         National Status and Trends (NS&T) "Mussel Watch" Program.

                             The American oyster, Crassostrea virginica, was proposed as the organism of interest

                         for this study due to its wide distribution in the U.S.A. coastal areas, its importance as an

                         economic resource, and its suitability as a sentinel organism for monitoring coastal

                         pollution (Goldberg et al., 1978; Bums & Smith, 1981; Farrington et al., 1983; Wade et

                         al., 1988a). PCBs, PAHs and tributyltin species were selected for study because of their

                         toxicity and ubiquitous distributions in the marine environment.







                                                                                                                     7




                      GALVESTON BAY SYSTEM



                          It is not the purpose of this section to present a thorough description of the Gal  veston

                      Bay system. The intention, instead, is to briefly describe the system in order to provide a

                      basic background for this study. Most of the following paragraphs are summarized from

                      Stanley's work (1989).

                          The Galveston Bay system (Fig. 1) includes the Galveston, Trinity, East and West
                      Bays, with a total area of nearly 1,430 km2. Water depth through the area is very

                      shallow. Average depths range from <1 m, in East and West Bays, to 2-4 m, in the lower

                      Galveston Bay. Upper Galveston and Trinity Bays average about 1.6 m in depth. The

                      maximum depths (up to 12 m) are found in the dredged channels, e.g. Houston Ship

                      Channel.

                          Main freshwater inflows to the Galveston Bay system include those from the San

                      Jacinto and Trinity River drainage areas. The Trinity River basin is the largest with a
                      drainage area of approximately 46,540 km2 and supplies about half of the total freshwater
                      input to Galveston Bay. The San Jacinto River basin has a much smaller drainage area
                      (10,230 km2). While the San Jacinto River is generally the main source of freshwater to

                      the lower Houston Ship Channel, the principal source of inflow during dry periods is

                      wastewater discharges. Smaller coastal drainage areas also contribute freshwater to the
                      bay system. Total coastal inputs represent a drainage area of about 2,000 km2. The
                      combined annual' freshwater inflow to the system averages 11.6 km3. In addition to these
                      overland runoffs, there is an average input of about 1.9 km3 each year fromprecipitation

                      directly onto the bays.

                          Mean salinity in the Galveston Bay system is around 177oo, but is highly variable in

                      time and space. Trinity Bay has generally the lower salinity, mainly because of the Trinity

                      River's outflow. Salinity along the western pan of Galveston Bay is typically higher than








                                                                                                               8






                                       95-                                                         94@30'


                                                                                           TEXA S





                                                                    A












                                                                                          P,

                                                                             EAS

                          29*30'




                                            .. .. . ...















                                                                    GALVESTON







                                                                    Site 1: Hanna Reef

                           WES                                      Site 2: Ship Channel




                                                   Fig. 1. Galveston Bay, Texas.





                                                                                                                    9




                       that on the eastern section. This is due to the Trinity River discharge from the east and to

                       the barrier formed along the Houston Ship Channel. This channel is the primary path for

                       salinity intrusion into upper Galveston Bay. Mean water temperature for the entire

                       Galveston Bay system averages about 220C, although the water temperature follows very

                       closely the seasonal changes in air temperature.

                           The Galveston Bay system constitutes one of the largest and most economically

                       important estuaries along, the Texas Gulf coast. For many years, this area has been the

                       recipient of various environmental injuries because of an aggressively growing urban and

                       industrial development. Houston, Deer Park, Baytown, Texas City and Galveston,

                       surrounding Galveston Bay to the north and west, are some of the most               ' heavily

                       industrialized areas in Texas. Hundreds of industrial plants, including petrochemical

                       complexes and refineries, bordering the Galveston Bay estuarine system are likely to

                       introduce significant amounts of organic pollutants into the Bay. Early ecological studies

                       showed the damaged suffered by different areas in Galveston Bay. Hohn (1959) and

                       Chamber & Sparks (1959) reported significant decreases in diatom species diversity and

                       number of invertebrates and fish in the upper Houston Ship Channel. Fish species

                       diversity indices were also used to assess the health of Galveston Bay (Betchtel &

                       Coperland, 1970). A change in species diversity from sciaenids to anchovy was related to

                       the influx of pollutants into the Bay. In general, these ecological studies suggested that

                       the waters of Galveston Bay contained pollutants in sublethal amounts, which caused

                       stress to organisms resulting in significant changes in the estuarine community structure.







                                                                                                                 10











                                                            CHAPTER H




                         BIOAVAnABILITY OF PAHs TO THE AMERICAN OYSTER (CRASSOSTREA

                                                  VIRGINICA): A FEELD STUDY



                      INTRODUCTION



                          Ile ability of marine invertebrates to incorporate polynucleararomatic hydrocarbons

                      (PAHs) from polluted aquatic environment has been documented by different authors

                      (e.g. Mix, 1984; Pruell er al., 1986, 1987; McElroy et al., 1989). In this chapter, the

                      uptake and release of PAHs, under field conditions, by two groups of American oysters

                      (Crassostrea virginica) with different pollution histories, are reported and compared.

                      Oysters from Hanna Reef, a relatively uncontaminated area in Galveston Bay, were

                      transplanted to a site near the Houston Ship Channel, a highly polluted area, to assess the

                      accumulation of PAHs over a period of seven weeks. Concentrations in transplanted

                      oysters were compared to the levels encountered in indigenous Ship Channel oysters.

                      After the uptake period, the remaining Hanna Reef oysters were back-transplanted to their

                      original geographic location to monitor the depuration of the bioaccumulated organic

                      contaminants. At the same time, indigenous Ship Channel organisms were transplanted to

                      the Hanna Reef area to compare depuration rates of PAHs between both groups of

                      oysters, i.e. newly and chronically contaminated oysters.













                        PAHs: A REVIEW



                        Background Information

                            The literature regarding the analytical chemistry and occurrences in environmental

                        samples of polynuclear aromatic hydrocarbons (PAHs) has been adequately reviewed in

                        several recent articles and books (e.g. National Academy of Sciences). Therefore, only a

                        general discussion of the most important aspects of these trace organic contaminants

                        related to this study is presented here.

                            Polynuclear aromatic hydrocarbons (Fig. 2) are one of several classes of organic

                        pollutants that are released into the environment, due in large part to human activities, and

                        are widely distributed in soils, waters, sediments and organisms throughout the world

                        (e.g. National Academy of Sciences, 1975, 1985; Neff, 1979; Giesy et al., 1983). PAHs

                        are composed of carbon and hydrogen atoms arranged in the form of two or more

                        aromatic (benzene) rings that are either fused (e.g. naphthalene) or linked (e.g. biphenyl)

                        with occasional incorporation of cyclopentene or cyclohexene rings (e.g. indeno[1,2,3-

                        c,d]pyrene). These hydrocarbons range in molecular weight (MW) from naphthalene

                        (C I ()H 12, MW 128.16) to coronene (C24H 12, MW 300.26).

                            Until the late 1970s, it was generally considered that PAHs were formed only during

                        high-temperature (e.g. 700'Q pyrolysis of organic materials. The discovery in fossil

                        fuels of complex mixtures of PAHs spanning a wide molecular weight range has led to the

                        conclusion that, given sufficient time (e.g. millions of years), pyrolysis of organic

                        materials at temperature as low as 100- 1 50'C can lead to production of PAHs (Blumer,

                        1976). In addition, there is some experimental evidence that a wide variety of organic

                        molecules containing fused-rings polyaromatic systems are synthesized by bacteria, fungi

                        and plants; although this contributes little to the global PAH burden in the environment

                        (Neff, 1979).







                                                                                                                        12






                                                                       PAHs


                                           2-Rings:

                                                                                                          H3



                                                Naphthalene                              2-Methyl Naphthalene


                                           3-Rinas:





                                                Anthracene                                   Phenanthrene


                                           4-Rings:




                                             Senz(a)anthracene                                 Chrysene

                                           5-Rings:







                                              Senzo(a)pyrene                             Dibenz(a,h)anlhracene


                                           6-Rings:






                                                                  lndeno(1,2,3-c,d)pyrene


                         Fig. 2. Structures and common names of selected aromatic hydrocarbons discussed in
                                                                    the text.







                                                                                                                   13




                           Although petroleum is not the only source of hydrocarbons to an ecosystem, most of

                        the evaluations of environmental concentrations of hydrocarbons are based on the analysis

                        of total or selected individual compounds that are indicative of petroleum pollution. Major

                        inputs of petroleum hydrocarbons to the coastal marine environment include drilling

                        operations and petroleum production, transportation activities, coastal and/or riverine

                        inputs, combustion of fossil fuels and atmospheric fallout. Cycloalkanes, branched

                        alkanes, n-alkanes and low molecular weight aromatic compounds are the predominant

                        hydrocarbons present in petroleum.

                           In addition to petroleum sources, aromatic hydrocarbons, particularly high molecular

                        weight PAHs, are introduced into the environment from different sources, e.g. pyrolysis

                        of organic materials, municipal incinerators, natural fires and coal production and

                        burning. Because of the persistence and lipophilic nature of PAHs, it is not surprising

                        that they have been frequently detected in biota, sediment and water samples from a wide

                        variety of polluted and unpolluted habitats. In general, the presence of petroleum

                        hydrocarbons in earlier studies has been inferred from the distribution of normal alkanes

                        and the presence or absence of an unresolved complex mixture (UCM) in the aliphatic

                        fractions. Since most of these studies were conducted before the introduction of capillary

                        columns, identifications of individual aromatic compounds were not confirmed by gas

                        chromatography/mass spectrometry (GC/MS).

                           It is estimated that more than 230,000 metric tons of PAHs reach the aquatic

                        environment each year by a variety of routes and accumulate in estuaries and coastal

                        marine areas (Giesy el al., 1983). Particularly important sources of PAHs are the

                        discharges of domestic and industrial wastes and runoff from land. For example, urban
                        runoff entering Narragansett Bay account for 7 1 % of the total inputs of PAHs (Hoffman

                        ei al., 1984), whereas riverine contribution of PAHs to coastal sediments off Washington

                        State was reported to be >30% of the total sediment load (Prahl et al., 1984). Generally,







                                                                                                               14



                      PAHs are detected in part per million (ppm) in organisms and sediments and in part per

                      billion (ppb) in water samples.

                          Toxicity of the different PAH compounds differs. Unsubstituted two- or three-ring

                      PAHs such as, for example, anthracenes, fluorenes, naphthalenes and phenanthrenes,

                      exhibit significant acute toxicity and other adverse effects on organisms but are

                      noncarcinogenic. In contrast, four- to seven-ring PAHs such as, for example,

                      benzo(a)pyrene, are significantly less toxic but are demonstrably carcinogenic, mutagenic

                      or teratogenic to a wide variety of animals including mammals (Kennish, 1992).

                      Polynuclear aromatic hydrocarbons of environmental concern are those compounds

                      having relatively high volatility and/or solubility.



                      Distribution and Occurrence in Galveston Bay

                          A number of studies have been conducted in the Galveston Bay area to establish

                      baseline concentrations of petroleum hydrocarbons in organisms; however, reports of

                      individual aromatic concentrations or distributions are limited (Table 1). Most of these

                      studies were conducted with organisms, particularly bivalves.

                          Oysters collected from several polluted and unpolluted locations in Galveston Bay in
                      November 1969 and January 1971 had total PAHs that ranged from 11.0 to 237 ng g- I

                      (Fazio, 1971). The highest PAHs in oyster tissues from contaminated sites were
                      fluoranthene (7.8 ng g-1), pyrene (6.5 ng g-1), benzo(b)fluoranthene (2.2 ng g-1), and
                      benzo(e)pyrene (2.1 ng g-1). Benzo(a)pyrene was below detection in samples from both

                      contaminated and uncontaminated stations.

                          Much higher concentrations were reported for oyster samples from a heavily polluted

                      area, Morgan's Point Reef, near the entrance of the Houston Ship Channel (Ehrhardt,

                      1972). Concentrations of aromatic hydrocarbons, mainly mono-, di-, and tricyclic
                      aromatics, were higher than those of alkanes (134,000 and 102,000 ng g- 1, respectively).
















                                                                                         TABLE 1
                      Hydrocarbon Concentrations in Samples from the Galveston Bay Area. Except Where Indicated, Concentrations in Organisms Are Expressed in
                      ng g- I on a Wet-Weight Basis. Concentrations in Sediment and Water Samples Are Expressed in ng g-1, on a Dry-Weight Basis, and in ng 1-1,
                                                                           Respectively. Ranges in Parenthesis.


                    Location                    Sample        Total HCs     Total Aromatic HCs            Individual PAHs                      Reference


                    Galveston Bay               oysters                               (11-237)       fluoTanthene= 7.8                         Fazio, 1971
                                                                                                     pyrenc= 6.5
                                                                                                     benzo(b)fluoranthenc= 2.2
                                                                                                     benzo(e)pyrene= 2.1
                                                                                                     benzo(a)pyrene= n.d.
                    Houston Ship Channel        oysters         236,000                134,000                                                 Ehrhardt, 1972
                    Morgan's Point Reef         oysters         160,000                                                                        Anderson, 1975
                    Halfway Reef                oysters          26,000                                                                        Anderson, 1975
                    East Bay                    oysters          <2,000                                                                        Anderson, 1975
                    West Bay                    oyster           <2,000                                                                        Anderson, 1975
                    Galveston Bay               oysters                                              pyrene= 1,010                             Farrington et al, 1980
                                                                                                     fluoranthenc= 940
                    Morgan's Point Reef         oysters                                              benzo(a)pyrene= 0. 12                     Murray et al., 1980
                    YachtClub                   oysters                                    615       pyrene= 212 (55-481)                      Fox, 19880)
                                                                                   (319-1,020)       fluoranthene= 112 (55-219)
                                                                                                     chrysene= 97 (<20-146)
                    Todd's Dump                 oysters                                     134      pyrene= 31 (<20-63)                       Fox, 19880)
                                                                                    (94.7-183)       fluoranthene= 12 (<20-57)
                                                                                                     chrysene= <20 (<20-36)














                                                                                        TABLE I
                                                                                        (continued)





                   Location                  Sample          Total HCs     Total Aromatic HCs            Individual PAHs                       Reference


                   Confederate Reef            oysters                                     610       pyrene= 146 (40-293)                      Fox, 1988(l)
                                                                                  (259-1,120)        fluoranthene= 210 (55-404)
                                                                                                     chrysene= 61 (28-87)
                   Hanna Reef                  oysters                                     ill       pyrcne= <20 (<20-25)                      Fox, 19880)
                                                                                    (21.3-228)       fluoranthcnc= <20 (<20-37)
                                                                                                     chryscnc= <20
                   Morgan's Point Reef         oysters                                   5,783       pyrcnc= 2,170 (669-3.9 10)                Scricano(l)
                                                                               (2,270-10,120)        nuoranthene= 738 (317-1,120)              (unpublished data)
                                                                                                     chrysene= 632 (260-1,090)
                   San Luis Pass               Fish, crab,                                           benzo(a)pyrene= <0.01                     Murray et al., 198 1 a
                                               shrimp
                   Houston Ship Channel        Cormorants                                            naphthalene= (20-40)                      King et al., 1987(2)
                                                                                                     fluoranthene= (n.d.-70)
                                                                                                     pyrene-- (20-240)
                                                                                                     benzo(a)pyrene= (40-110)
                                                                                                     chrysene= 130
                                                                                                     benzo(g,hj)perylene= 590
                                                                                                     benzoWfluoranthene= 40
                                                                                                     1,2,4,5-dibenzoanthracene= 20

                                                                                                                                                                                    ON















                                                                                    TABLE I
                                                                                    (continued)





                  Lmation                  Sample         Total HCs     Total Aromatic HCs           Individual PAHs                     Reference


                  Trinity Bay                sediments       96,100                34,200        dimethyl naphthalenes= 8,000            Armstrong et al., 1979
                                                                                                 tfimethyinaphthalenes= 10,000
                                                                                                 C4- naphthalenes= 9,000
                                                                                                 dimcthylbiphenyls= 800
                  San Luis Pass              sediments                                           bcnzo(a)pyrenc= 2.2 (0.01-6.0)          Murray et al., 198 1 a


                  Trinity Bay                water           10,500                10,500        benzene= 1,500                          Armstrong et al., 1979
                                                                                                 toluene= 3,200
                                                                                                 C2- benzene= 3, 100
                                                                                                 C3- benzene= 800
                                                                                                 dimethyinaphthalenes= 700
                  San Luis Pass              water                                               benzo(a)PyTcne= n.d.                    Murray et aL, 198 1 a

                  n.d.= not detected; (1) ng g- I on a dry-weight basis; (2) geometric mean







                                                                                                                 18




                      Anderson (1975) reported similar concentrations of total hydrocarbons in oysters collected
                      at the same general location (160,000 ng g-1). At Halfway Reef, a few miles farther

                      away from the entrance of the Houston Ship Channel toward the center of Galveston Bay,
                      26,000 ng g-1, wet weight, of total hydrocarbons were detected while oyster samples
                      collected in the East and West Bays had less than 2,000 ng g-I of total hydrocarbons in

                      their tissues. Benzo(a)pyrene in oysters collected during May 1979 near Morgan's Point
                      Reef ranged from 0.07 to 0. 14 ng g- I with a mean of 0. 12 ng g- I (Murray et al., 1980).

                          In 1980, Farrington et al. published the hydrocarbon concentrations measured in

                      bivalves collected from 90 to 100 stations around the U.S. coastline during the EPA

                      "Mussel Watch" Program (1976-1978). Oysters collected in the Galveston Bay area
                      during 1977-1978 had concentrations of 940 and 1,010 ng g- I for fluoranthene and

                      pyrene, respectively.

                        . Fox (1988), in a study designed to examine the spatial and temporal variations in

                      concentrations of selected organic contaminants in Galveston Bay, reported the PAHs

                      concentrations in oysters from three stations at four sites sampled during 1986. Total

                      PAHs were higher in samples from sites located closer to urban areas. Oysters collected
                      in the proximity of the Houston Yacht Club (615 ng g- 1, range = 319-1,020 ng g- 1) and
                      Confederate Reef (610 ng g-1, range = 259-1,120 ng g-I), near the city of Galveston,

                      had annual average concentrations higher than samples collected in the Todd's Dump area
                      (134 ng g-1, range = 94.7-183 ng g-I), located in the middle of Galveston Bay, and
                      Hanna Reef (I'll ng g-I, range = 21.3-228 ng g-I), in the East Bay. Pyrene,

                      fluoranthene, chrysene, phenanthrene and 1-methyl phenanthrene were the most

                      frequently detected analytes. Although temporal variations of individual PAHs in oysters

                      from the Galveston Bay area did not present an easily recognizable trend during this

                      study, it seemed evident that total PAHs in samples from the most polluted sites, i.e.

                      Houston Yacht Club and Confederate Reef, were lower during the summer. This







                                                                                                                  19




                       observation is confirmed by data produced during a six month study with oysters from the

                       upper part of Galveston Bay. Oysters collected monthly near the entrance to the Houston

                       Ship Channel were analyzed for a number of organic contaminants between December
                       1988 and June 1989. Ile maximum total PAHs measured in February (10,100 ng g-l'
                       range = 9,680-10,600 ng g- 1) decreased to 2,270 ng g- I (range = 1,840-2,7 10 ng g- 1) in

                       May. Pyrene, fluoranthene, chrysene, benz(a)pyrene and benzo(e)pyrene were the most

                       abundant PAHs detected during that study (Sericano, unpublished data). Temporal

                       variations of trace organic contaminants in bivalves were also reported for DDT (Butler,

                       1973) and PCBs (Farrington et al., 1993). Other marine organisms collected at San Luis

                       Pass, located in West Galveston Bay at the west end of the Galveston Island, were

                       analyzed for benzo(a)pyrene (Murray et al., 198 1 a). In all cases, concentrations were
                       below the detection limit (<O.O I ng g- 1).

                           In 1987, King et al. reported the concentrations of selected PAHs in double-crested

                       cormorants, a fish-eating bird near the top of an aquatic food web, wintering in the

                       Houston Ship Channel. This cormorant is rarely found in the area during summer

                       months. Naphthalene and fluoranthene were the only PAHs present in individuals

                       collected at the beginning of the study. After the three-month winter period, eight

                       aromatic hydrocarbons were detected in bird carcasses (Table 1).

                           Reports of PAHs in sediment and water samples from the Galveston Bay area are

                       limited. In 1979, Armstrong et al. reported the results of a study conducted from April

                       1974 to December 1975 to examine the effects of brine effluents from a producing

                       platform in Trinity Bay on the surrounding benthic communities. Total petroleum
                       hydrocarbons measured in sediments collected near the platform were 96,100 ng g-l.
                       Approximately one third of this total (i.e. 34,200 ng 9-1) were aromatic hydrocarbons,

                       mainly dimethyl-, trimethyl-, and tetramethylnaphthalenes. Bottom water samples

                       collected at the same site contained mostly monoaromatic compounds, e.g. toluene,







                                                                                                               20



                      benzene, and C2-benzene, in the 200-3,200 ng 1-1 range. Total PAHs in water was
                      10,500 ng 1-1. Sedimentary PAHs decreased with distance from the platform to near
                      background levels (2,000-6,000 ng g-1). There was a definite inverse correlation

                      between sedimentary PAHs and the number of benthic species and individuals present.

                      The Bay bottom was almost completely devoid of organisms within 15 m of the effluent

                      outfall. Stations located 455 m from the platform were unaffected. Sediment samples

                      collected in the San Luis Pass area had an average benzo(a)pyrene concentration of 2.2 ng
                      9_1 (range = 0.01-6.0 ng g-1; Murray et al., 1981a). Benzo(a)pyrene was not detected in

                      water samples from that area.



                      Bivalve Uptake and Depuration Studies

                         A considerable number of reports on the uptake and deputation of petroleum

                      hydrocarbons by bivalves have been published over the last two decades. In general,

                      bivalves can be exposed to petroleum hydrocarbons in the laboratory by any one or a

                      combination of several methods including water-soluble fractions (Neff & Anderson,

                      1975; Neff et al., 1976; Lee et al., 1978; Nunes & Benville, 1979; Jovanovich & Marion,

                      1987; Axiak et al., 1988), water dispersion s/sol ution s (Boehm & Quinn, 1973; Stegeman

                      & Teal, 1973; Stainken, 1975; Wong, 1976; Fossato & Canzonier, 1976; Stainken, 1977;

                      Fucik & Neff, 1979; Riley er al., 198 1; Tanacredi & Cardenas, 199 1), contaminated food

                      (Roesijadi er al.,-1978; Fortner & Sick, 1985) and contaminated sediments (Palmork &

                      Solbakken, 198 1; Obana et al., 1983; Pruell et al., 1986, 1987). Similarly, experimental

                      field studies include exposures to water soluble fractions (Wolfe et al., 1981), water

                      dispersion$/solutions (Fucik et al., 1977) and contaminated sediments (Roesijadi er al.,

                      1978). Alternativelyj uptake and/or deputation studies can be performed in the field by

                      transplanting uncontaminated bivalves to contaminated areas (e.g. Sericano et al., in

                      press) or relocating chronically contaminated bivalves into pristine environments (e.g.







                                                                                                                      21




                        Pittinger et al., 1985) or   in tanks in the laboratory (e.g. Boehm & Quinn, 1977).

                        Bivalves are generally reported to preferentially bioaccumulate four-, five- and six-ring

                        PAHs when exposed, in the laboratory, to naturally contaminated sediments (e.g. Pruell

                        et al., 1986, 1987) or in the environment (e.g. Bjorseth et al., 1979), with little, if any,

                        uptake of two- and three-ring PAHs. However, oysters from the Gulf of Mexico were

                        reported to preferentially uptake two- and three-ring PAHs when compared to four-, five-

                        and six-ring PAHs (Wade et al., 1988c).

                           There is some disagreement in the published literature regarding the accumulation of

                        individual PAHs and their half-lives in different bivalves. For example, the order

                        chrysene > benzo(b)fluoranthene > fluoranthene > benzo(a)pyrene > benzo(a)-anthracene

                        encountered in mussels (Pruell et al., 1986) do not agree with the accumulation order

                        pyrene > benzo(e)pyrene > benzo(b)fluoranthene > benzo(a)anthracene reported for clams

                        (Obana et al., 1983). Both bivalves were exposed in the laboratory to contaminated

                        sediments. Similarly, the estimated half-lives for fluoranthene and benzo(a)anthracene

                        reported for mussels (30 and 18 days, respectively; Pruell et al., 1986) disagree with the

                        half-lives encountered in oyster (5 and 9 days, respectively; Lee et al., 1978)

                           Most previous studies have indicated significant but incomplete depurations of

                        aromatic hydrocarbons by different bivalves (e.g. Fossato & Canzonier, 1976; Pruell et

                        al., 1986, 1987; Sericano et al., in press). However, some studies reported a complete

                        depuration of different PAHs to levels below detection limits after relatively short periods

                        of time, i.e. less than a week. Wormell (1979), for example, reported that depuration
                        studies with chronically contaminated oysters showed no preferential retention"Of

                        saturated or aromatic hydrocarbons. Depuration was rapid and nearly complete with a

                        biological half-life of 4.4 days for total accumulated hydrocarbons. The report suggests,

                        however, that seasonally related conditions might be a significant factor in the ability of







                                                                                                                   22




                       oysters to clean themselves since individuals depurated in December and January retained

                       a significant fraction of the bioaccumulated hydrocarbons.

                           Pittinger et al. (1985) indicated that contaminated oysters (Crassostrea virginica),

                       transplanted to a nonimpacted site depurated PAHs to undetectable levels within four days

                       of relocation.    Other studies did not detect any depuration. Tanacredi & Cardenas

                       (1991), for example, reported that laboratory exposed clams (Mercenaria mercenaria) did

                       not show evidences of decreasing trends in accumulated PAHs after a 45-day depuration

                       period. Similar results were reported by Boehm & Quinn (1976). In that study,

                       chronically contaminated clams (Mercenaria mercenaria) failed,to release the accumulated

                       PAHs when relocated to clean seawater over a four-month period. Both reports,

                       however, seem to be in disagreement with the vast majority of previous investigations

                       involving bivalves.

                           In spite of the abundant information, it is clear from the preceding discussion that

                       there are many contradictions in the published literature. The reasons for these

                       disagreements are difficult to explain. It is possible, however, that the extremely high oil

                       or individual analyte concentrations used in some studies, the presence of stressed animals

                       and the use of different experimental designs or analytical techniques could be responsible

                       for the observed discrepancies.



                       UPTAKE AND DEPURA71ON OF PAHs



                       Experimental Design, Sample Collection and Methods

                           In December 1988, approximately 250 oysters were collected by dredge at Hanna
                       Reef, a relatively pristine area in Galveston Bay (Fig. 3). Within 24 hr., these oysters
                       were transplanted live, in net bags, to a site near the Houston Ship Channel, an area

                       where oysters have high PAH concentrations (Wade et al., 1988a). Photographs of both








                                                                                 23




                                                                         94@30'


                                                                   T E X A S


                                                       A






                                              91








                                                        EAST

                   29*30,







                                                       N










                                     40           GALVESTON
                                       0







                             A
                                                  Site 1: Hanna Reef

                    W                                    2: c?hip Channel
                                                  Site




                                    Fig. 3. Galveston Bay transplantation sites.






                                                                                                                   24




                         sites, nets and oysters are shown in Fig. 4. Thereafter, oysters were sampled in groups

                         of 20 individuals during the 3rd, 7th, 17th, 30th and 49th days after transplantation.

                         During the uptake period, native oysters were collected from the Ship Channel area to

                         compare their concentrations of these trace organic contaminants with those encountered

                         in transplanted Hanna Reef oysters.

                             The remaining transplanted oysters, i.e. approximately 150 individuals, were re-

                         located to the Hanna Reef area and sampled in groups of 20 individuals during the 3rd,

                         6th, 18th, 30th, and 50th days after transplantation. The transplant experiment to the

                         Hanna Reef area was duplicated with approximately 150 native oysters from the Houston

                         Ship Channel area in order to compare depuration dynamics in both populations. In the

                         following sections, Ship Channel, Hanna Reef, transplanted Hanna Reef-to-Ship

                         Channel, transplanted Ship Channel-to-Hanna Reef and relocated Hanna Reef-to-Ship

                         Channel-back to-Hanna Reef oysters are refered as SC, HR, HRSC, SCHR and

                         HRSCHR oysters, respectively. Sediment and water samples were collected during

                         oyster sampling days for PAH analyses.



                         Extraction andfi-actionation of PAHs

                            The analytical procedure used was based on a method developed by MacLeod et al.

                         (1985) with a few modifications that proved to be equivalent or superior to the original

                         techniques. The analytical scheme is summarized in Fig. 5 Precleaning of all glassware

                         involved extensive washing with Micro cleaning solution, rinsing with distilled water and

                         combustion at 400*C for 4 hrs. All solvents were glass-distilled nanograde purity, e.g.

                         Burdick & Jackson. Solvent purity was checked, after 300-fold concentration, by gas

                         chromatography/mass spectrometry (GC/MS). Each set of samples (8-10) was

                         accompanied by a complete system blank and spiked blank or reference material that were

                         carried through the entire analytical procedure. Before extraction, PAH internal standards
























                                                                                                     Alf,   Or


                                                                                                         -,FAA,.
                                                         A,, ilbm

                                         Fig. 4. Exposure (a) and depuration  (b) sites. respectively. Approximately 250 adult oysters (c) w
                                                                              transplanted in net bags (d).





                                                                                                                                                                                                         26







                                                                                                                                                                 ST-D I M I, NT
                                                                          TISSUE                                                                                       i
                                                                     WARM TO ROOM                                                                                HOMOGENIZE
                                                                      TEMPERATURE                                                    DRY         .911  1
                                                                                                                                   W IGHT                        ADDITJONOF
                                                                                                                                                                 INTERNAL STANDARVS
                                                                       HOMOGLNUE



                                                                                                                                                                 EXTJLACTTO%i
                                                                      ADDITION OF
                                                                 M.FERNAL STANDA RDS                                                               t. C5 em               100 mi
                                                                                                                                                   2. CH,        OMICK2 CS 000-1
                                                                                                                                                   J. v@         Cs   I 1 100 ml K j
                                                                    COLD EXTRACTION                                                                              PA RTITION                Wate,
                                                                   cm, q     1   3 N 100 mi                                                                      WITH S..CL SOLUTION       pho"
                                                                                                                                                                        Organic phole
                                                                       CENTRI]FUGE                                                                               CONCE.NTRATE

                                                                      CON       RATE
                                                                          CENT
                                                                             i                                                                                   COPPER TREATMENT

                                                                         COLUNIN,
                                                                    CHROMATOGR.Aplly@                                                                  U,          =Rol   NAPH Y

                                                                                                           CONCENTRATED EXTRA--)
                                                                                                                         I

                                                                                                            ALUMINA / SILICA GFL
                                                                                                               CHROMAT'DGILAPSY






                                                                                      ALIPHATIC                       PAH.  @6                  OTHER POLAR
                                                                                    HYDROCARBONS                  PEST. & PCB's                    ORGANICS




                                                                                    GC/FID; GCI%4S                  SEPIIADEX                  ccrlf); GC/MS




                                                                                                                  TOT.     PAH',                DERI%IZATION



                                                                                                                                            Siructure Coortr",   ation



                                                                                                                                               GC-'FID; CC/.-.fS




                                                                                                 GCIFID; GCISIS                  CCIECD; CCIMS                   T


                                                                                             --@o p-           R REDUCTION/RNRLYSIS
                                                                                             L                T
                                                                                                                                                       @
                                                                                                                                                                 UOM    MZE




                                                                                                                                                                 A
                                                                                                                                                                 R
                                                                                                                                                                  AL 11ANIA..11


































































                                                                                                                                                                     FLORISIL
                                                                                                                                                                 HROMATOGRAPHY






                                                                                  Fig. 5. Trace organic analytical scheme.







                                                                                                                     27




                         (d8-naphthalene, djo-acenaphthene, djo-phenathrene, d12-chrysene and d12-perylene)

                         were added to all samples, blank and spiked blank. These standards were added at a

                         concentration level similar to that expected for the sample components of interest.

                             Approximately 15 g of wet tissue were used for the analysis of PAHs in oysters.

                         After the addition of 50 g of anhydrous Na2SO4, the tissue was extracted three times with

                         100 ml of methylene chloride using a "Tissurnizer" homogenizer. The organic phase was

                         concentrated to 10-15 ml in a flat-bottom flask equipped with a three ball Snyder

                         condenser. Kudema-Danish tubes were heated in a water bath at 60'C, to concentrate the

                         extracts to a final volume of 2 ml in hexane.

                             Approximately 50 g of sediment (wet weight) were used for analysis. The sediments

                         were sequentially extracted on a roller table with 100 n-d of methanol (I h), 100 ml of 1: 1

                         methanol:methylene chloride (I h) and three portions of 100 ml of methylene chloride (16,

                         3 and I h, respectively). The combined extracts were partitioned into two phases by

                         addition of acidic NaCl solution (10%, pH=2). The combined extracts were concentrated

                         to 1-2 ml as previously described for oyster extracts.

                             Fifteen to 17 1 of seawater samples were acidified with HCl (pH=2) and extracted, for

                         15 min, with 500 ml of methylene chloride. The extraction was repeated three times. The

                         organic phase was partitioned against an acidic NaCl solution (pH=2). The extract was
                         then dried with anhydrous Na2SO4 and concentrated to 1-2 ml as previously described

                         for oyster extracts.

                             Tissue, sediment and water extracts were fractionated by alumina: silica (80-100

                         mesh) column chromatography. The silica gel was activated at 170'C for 12 h and

                         partially deactivated with 5% distilled water. Twenty grams of silica gel were slurry

                         packed in methylene chloride over 10 g of alumina. Alumina was activated at 400"C for 4

                         h and partially deactivated with 1 % distilled water. Activated copper was added to the top

                         of the column for sediment samples to remove any residue of elemental sulfur. The







                                                                                                                    28




                          methylene chloride was replaced with pentane and the extract was applied to the surface of

                          the column. The column was sequentially eluted with 50 ml of pentane (f 1), 200 ml of

                          1:1 methylene chloride:pentane (U) and, for sediments, 50 ml of methanol (6). The f2

                          fraction, which contains the polynuclear aromatic and chlorinated hydrocarbons, was

                          concentrated as previously described. The f2 fraction from oyster samples was further

                          purified by Sephadex LH-20 column (25-100 mesh) to remove lipids (Ramos &

                          Prohaska, 1981). The column was eluted with 140 ml of a cyclohexane:methanol:

                          methylene chloride (6:4:3) mixture. The first 40 ml were discarded and the next 100 nil

                          fraction was concentrated to a final volume of 0.5-1 ml, in hexane, for gas

                          chromatographic/mass spectrometry analysis.



                          1nstrwwnW analysis

                             PAHs were quantitatively analyzed by GC/MS in a selected ion mode (SIM) utilizing

                          the molecular ions of the components of interest. A 30 m DB-5 capillary column (0.31

                          mm i.d., 0.052 mm film thikness) was temperature programmed from 40 to 3000C at
                          10'C min-I and hold at 300'C for 10 min. The GC/MS was calibrated by injections of

                          standard solutions at three different concentrations. Sample analytes were quantified from
                          a first degree calibration curve with an R2 value equal to or greater than 0.99. Analyte

                          identity was confirmed by their molecular weights and retention times of authentic

                          standards.



                          Ancillwyparairwers

                             Grain size analysis was performed by the procedure of Folk (1974). Briefly,
                          reffigerated samples were homogenized, treated with 30% H202 to oxidize organic matter

                          and washed with distilled water to remove soluble salts. Sodium hexametaphosphate was

                          added to deflocculate each sample before they were wet-sieved though a 62.5 micron (4.0







                                                                                                                      29




                          phi) sieve to separate gravel and sand from the silt and clay fraction. ne total gravel and

                          sand fraction was then oven dried at 40*C and weighed. The silt-clay fraction was

                          analyzed for particle size distribution by the pipette (settling rate) method.

                             Extractable lipids in oysters were determined on an aliquot of the sample extracts.

                          Twenty nil of the combined oyster extracts were withdrawn from the total volume and

                          evaporated to dryness under N2 gas. The residue was redisolved in I ml of methylene

                          chloride, 0. 1 ml was evaporated on a paper pad and the residual materials weighed using a

                          Cahn 29 electrobalance.



                          Statistical analysis

                             During the uptake period, one-way analyses of variance (ANOVA) were performed on

                          the analyte concentrations to evaluate the bioconcentration by transplanted oysters relative

                          to indigenous individuals. Slopes of the least-square linear regressions of the logarithm

                          of the concentrations (log Q versus time (t) for the depuration period were tested for

                          statistical significance.



                          Uptake of PAHs by Transplanted Oysters

                             Average PAH concentrations measured in SC and HRSC oyster, sediment and water

                          samples, during the first part of this experiment at the Ship Channel site, are reported in

                          Tables A-2 and A-3 (Appendix).

                             The concentrations in Ship Channel oysters represent the time-integrated amounts of

                          trace organic contaminants accumulated from solution, particles and/or food minus any

                          metabolism and/or depuration of these comp    ounds. The concentrations of most of these

                          PAHs in SC oysters did not change significantly during the first phase of the experiment.
                          Total aromatic hydrocarbon concentrations in SC oysters averaged 3,800ï¿½590 ng g-l
                          (range 3,200 to 4,400 ng g-1) over the seven-week uptake period. The fluctuations







                                                                                                                   30




                          observed in the concentrations of the lower molecular weight PAHs with time were,

                          however, comparatively greater than the variability encountered in the concentrations of

                          the higher molecular weight analytes. Naphthalene, 2,6-dimethyl-naphthalene and

                          phenanthrene, for example, had an overall average of 13ï¿½8.3, 25ï¿½16 and 54ï¿½37 ng g-

                          during this period with coefficient of variations of 64, 64 and 69%, respectively. These

                          coefficients of variations were larger than those observed for pyrene (1,500ï¿½290 ng g-
                          19%), benzo(e)pyrene (270ï¿½65 ng g- 1; 24%) and perylene (I 30ï¿½22 ng g- 1; 17 %) during

                          the same period of time.

                             Concentrations of PAHs in HRSC oysters increased dramatically during the seven-

                          week exposure period. Concentrations of total PAHs in transplanted HRSC oysters
                          increased from an initial total concentration of 290 to 4,400 ng g- I during this period.

                          Four- and five-ring PAHs were rapidly accumulated by HRSC oysters; comparatively,
                          two-, three- and six-ring PAHs were detected in low concentrations in both transplanted

                          HRSC and indigenous SC oysters (Fig. 6). One month after the experiment started, no

                          statistically significant differences were observed in the distributions of PAHs, by ring

                          number, between HRSC and SC oysters.

                             Generally, the PAHs measured in HRSC oysters had similar concentrations to those

                          found in SC oysters in less than 20 days (Fig. 7). Four- and five-ring PAHs had

                          increased in the HRSC oysters while the two- and three-ring PAHs concentrations either

                          did not change (e.g. naphthalene, 2-methylnaphthalene) or increased only slightly (e.g.

                          2,3,5-trimethylnaphthalene, I-methylphenanthrene) during the seven-week exposure

                          period. A decrease was observed in the concentrations of some lower molecular weight

                          PAHs in transplanted oysters during the first week of exposure. These decreases in

                          concentrations were not observed in indigenous SC oysters. However, since this initial

                          decrease in the concentrations of low molecular weight hydrocarbons was not observed

                          for the higher molecular weight PAHs, it is unlikely that it was a consequence of stressed








                                                                                                                                                                                31



                                         4000   Ship Channel Site       0 day                                     4000,  Ship Channel Site       17 days
                                                                              M Banns ReerOysLers                                                      0 Bass& ReelOysters
                                                                              0 Ship Channel Oysters          It                                       M Ship Channel Oysters
                                                                                                              P..
                                         3000,                                                                    3000'


                                                                                                              at
                                         20M                                                                      2000



                                                                                                              6
                                         Iwo                                                                      low


                                                                                                                         Mniiiiiiiiii viiiii=
                                                   2           3           4          5            6                         2          3            4           5          6
                                                                  Number of Rings                                                          Number of Rings
                                                Ship Channel Site       3 days                                    4000-  Ship Channel Site       30 days
                                         4000                                                                                                          0 Hanna Reeroysters
                                                                              0  Hanna Reer Oysters
                                                                                                                                                       0 Ship Channel Oysters
                                                                              0 Ship Channel Oy.slers
                                                                                                                  3000-
                                   6     3000'


                                                                                                              -fAt
                                         2000                                                                     2000
                                                                                                              C


                                         low                                                                  5   1000
                                   W                                                                          Cc
                                                                                                              U        0
                                                                                   A               moog-
                                                    2          3           4                       6                         2          3            4           5          6
                                                                  Number or Rings                                                          Number or Rings
                                         4000' Ship Channel Site        7 days                                    4000-  Ship Channel Site       48 days
                                                                              M Hanna Reef Oysters                                                     0 Hanna Reef Oysters
                                                                              0  Ship Channel Oysters         1:                                          Ship Channel Oysters
                                         3000.                                                                V



                                         2000-                                                                    2000
                                   r

                                                                                                              V
                                                                                                              6
                                   r     1000                                                                     low
                                                                                                              Cc

                                                                                                                       0


                                                                  Number      of Rings                                                      Number     of Rings


                                          Fig. 6. Concentrations of polynuclear aromatic hydrocarbons, grouped by number of
                                          rings, in transplanted Hanna Recf and indigenous Ship Channel oysters during the 48-
                                           day exposure period near the Houston Ship Channel. Ship Channel oysters were not
                                                                                               sampled on day 7.
                                                                                                                       L                        Ion
















                                                Naplithalene                                                                               2-Methy1naphthalene

                                                                                                                                                                                         Hanna Reef Oystm
                                    J                                                                                          J
                                    It                                                       Ship chound Oysters                                                                         Ship Channel Oystas

                                          to"




                                           too-                                                                                       too







                                    U                                                                                          U

                                               6     1$     20     30     40     so     60     70     so     90     too                   0     to     20     30      40     so     60     70     go      98    too

                                                                            Time   (days)                                                                              Time   (days)

                                                2,3,5-TrImethyInaphthaIene                                                                 I-Methylphenanthrene
                                                                                              Hanna Reef Oysters                     10000.                                              Hanna Reer Oysters
                                    V                                                         Ship Channel Oysters                                                                       Ship Channel Oystffs

                                          10"                                                                                         100,
                                    V                                                                                          V



                                           too                                                                                        fee                 =--46
                                    C                                                                                                                          - ----------
                                    0


                                                                                                                                       to

                                                                                                                               C
                                                                                                                               0
                                    U        I                                                                                 U
                                                0    10     20     30     40     50     60     76     Be     90     foe                   0     10     20     30     40      50     60     70     Be      90    100
                                                                           11me (days)                                                                                 Time (days)

                                  Fig. 7. Concentrations of selected polynuclear aromatic hydrocarbons in tissues of Hanna Reef and Ship Channel oysters
                                            during exposure to the Ship Channel area contaminant levels and following transplant to the Hanna Reef area.





                                            Mi












                                               Pyrene                                                                               Denz(a)anthracene
                                                                                         HannaltedOysters                                                                       Hanna Red Oynters
                                                                                         Ship Channel Oysten                                                                    Ship Channel Oyden



                                    c                                                                                    at
                                                                                                                                IGO

                                                                                                                         .2


                                           It
                                                                                                                         c       10

                                                                                                                         c


                                              0    10     20    36     40     so    60     70    as      90   too                  0     to     20    30     40     50    60     70     so     90    too
                                                                        71 me  (days)                                                                         Time   (days)
                                        100"   Chrysene                                  Hanna ReefOysters                    too". Benzo(b)nuoranthene                         flannalledOyssers
                                                                                         Ship Channel Oyders                                                                    Ship Channel Oysters

                                                                                                                               to".




                                                                                                                                100
                                   C


                                                                                                                         L!


                                                                                                                         C


                                              9    10     20    30     40    50     69     70    80      90   too                  0     10     20    30     40     50    60     70     so     90    too
                                                                        Time (days)                                                                           Time (days)

                                                                                                           Fig. 7. (Continued)













                                                Denzo(&)pyrene                                                                     ftenzo(e)pyrene
                                                                                          Hanna Red 0yaterv                                                                    Hanna Red Oysten
                                      It                                                  Ship Channel Oysters          It                                                     Ship Channel Oysters
                                          If" -                                                                               0111111
                                                                                                                        V


                                      be                                                                                am


                                      C



                                           If
                                                                                                                        c

                                                                                                                        8
                                      U                                                                                 U
                                            I
                                              0     It    20     30    40     50     60    79     so    90    100                 0     10    20     30     40    50     60    70     so     90    100
                                                                         Time   (days)                                                                       Time   (days)
                                               Perylene                                                                             Benzo(g,h,I)perylene
                                                                                         Hanna Rftf0y.,Urs                                                                     Hanna Reef Oysters
                                                                                 ---w- Ship Channel Oysters                                                                    Ship Channel Oysters

                                                                                                                              Joe@-



                                          114111-                                                                              too



                                           it,                                                                          c       is

                                      C
                                      0
                                      U                                                                                 U
                                            I
                                              0     10    20    30     40     50    66     70    so     90    100                 0     10     20    30     40    50     60     70    so     96    100
                                                                        Time (days)                                                                          Time (days)


                                                                                                          Fig. 7. (Continued)








                                                                                                                     35



                         animals. By the, end of the exposure period, the concentrations of all the individual PAH

                         measured in transplanted oysters were not statistically differentiable from those

                         encountered in indigenous oysters (Fig. 8). The observed rapid bioconcentration of

                         PAHs is similar to the uptake curves reported in different studies involving bivalves either

                         in laboratory experiments (Nunes & Benville, 1979; Pruell et al., 1986; Tanacredi &

                         Cardenas, 1991) or in transplantion studies (Pittinger et al., 1985). The PAHs

                         accumulated to the highest concentrations in SC and HRSC oysters were: pyrene >

                         fluoranthene > chrysene > benzo(e)pyrene > benzo(b)anthracene. Three PAHs, pyrene,

                         fluoranthene and chrysene, accounted for about 60% of the total PAH load measured in

                         these oysters. Other uptake studies, using a variety of organisms exposed to different

                         sources of PAHs, produced a different order for the concentration of four- and five-ring

                         PAHs. For example, the relative abundances reported by Pruell et al. (1986) for mussels

                         (chrysene > benzo(b)nuoranthene > fluoranthene > benzo(a)pyrene > benzo(a)anthracene)

                         or by Obana et al. (1983) for clams (pyrene > benzo(e)pyrene > benzo(b)fluoranthene >

                         benzo(a)anthracene) are diferent from that found in this study for oysters. These

                         discrepancies might reflect the different PAH compositions in the sources or a different

                         uptake ability of the organisms.

                            The average concentrations of PAHs, by number of rings and individually, in Ship

                         Channel sediment and water samples are shown in Fig. 9 and 10, respectively. Water and

                         sediment samples were collected each time the oysters.were collected. Sediment samples

                         had higher relative concentrations of four- and five-ring PAHs when compared to

                         seawater samples. The relative abundances of PAHs in sediments were pyrene >

                         benzo(b)fluoranthene > benzo(e)pyrene > chrysene > benzo(a)pyrene > fluoranthene >

                         benzo(k)fluoranthene (Fig. 9). Two-ring PAHs and most of the three-ring PAHs were

                         detected at low concentrations in sediments. In contrast, two-ring PAHs, i.e.

                         naphthalenes, were the predominant PAHs in the seawater samples (Fig. 10). The








                                                                                                                           36








                                             Naphthalene
                                     2-Methylnaphthalene
                                     1-Methyinaphthalene
                                                Biphenyl
                                 2,6-Dimethylnaphthalene
                                          Acenaphthylene
                                            Acenaphthene
                               2.3,5-Trimethylnaphthalene
                                                Fluorene

                                            Phenanthrene

                                              Anthracene
                                    I-Methylphenanthrene
                                             Fluoranthene
                                                   Pyrene
                                       Benz(a)anthracene
                                                Chrysene
                                    Benzo(b)nuoranthene
                                    Benzo(k)fluoranthene
                                          Benzo(e)pyrene
                                          Benzo(a)pyrene
                                                Perylene                                     Ship Channel Oysters
                                  Indeno[1,2,3-c,dlpyrene
                                   Dibenz(a,h)anthracene                                     Hanna Reer Oysters
                                      Benzo(g,hJ)perylene                                                       r 7,

                                                          0          500         1000         1500         2000

                                                                    Concentration (ng/g, dry wt.)



                           Fig. 8. Concentrations of individual polynuclear aromatic hydrocarbons in tissues of
                              Hanna Reef and Ship Channel oysters at the end of the 48-day exposure period.








                                                                                                                            37





                                                         2

                                                         3

                                                         4



                                                         6

                                                           0         200        400         600        800        1000



                                              Naphthalene
                                      2-Methylnaphthalene
                                      I-Methyinaphthalene
                                                 Biphenyl
                                  2,6-Dimethyinaphthalene
                                           Acenaphthylene
                                             Acenaphthene
                                2,3,5-Trimethylnaphthalene
                                                 Fluorene

                                             Phenanthrene

                                               Anthracene
                                    I-Methylphenanthrene
                                             Fluoranthene
                                                    Pyrene
                                        Benz(a)anthracene
                                                 Chrysene
                                     Benzo(b)fluoranthene
                                     Benzo(k)fluoranthene
                                           Benzo(e)pyrene
                                           Benzo(a)pyrene
                                                 Perylene
                                   Indeno[1,2,3-c,d]pyrene
                                    Dibenz(a,h)anthracene
                                      Benzo(g,h,i)perylene

                                                           0        so                150       200      250       300

                                                                     Concentration (ng/g, dry wt.)

                          Fig. 9. Concentrations of polynuclear aromatic hydrocarbons, grouped by number of
                                         rings and individually, in Ship Channel sediment samples.







                                                                                                                         38








                                                          - ------ - ------- ---
                                                         2

                                                         3

                                                         4
                                                   Lw



                                                  z
                                                  z       0            5             10            15           20


                                              Naphthalene
                                      2-Meth)-inaphthalene
                                      1-Methyinaphthalene
                                                 Biphenyl
                                  2,6-Ditnethyinaphtholene
                                           Acenaphthylene
                                            Acenaphthene
                               2,3,5-Trimethylnaphthalene
                                                 Fluorene

                                             Phtnanthrene

                                               Anthracene
                                    1-Methylphenanthrene
                                             Fluoranthene
                                                   Pyrene
                                        Benz(a)anthracene
                                                 Chrysene
                                     Benzo(b)fluoranthene
                                     Benzo(k)fluoranthene
                                           Benzo(e)pyrene
                                           Benzo(a)pyrene
                                                  Perylene
                                   Indeno[1,2,3-cdjpyrene
                                    Dibenz(a,h)anthracene
                                      Benzo(g,hj)perylene

                                                          0        1        2         3        4        5        6


                                                                          Concentration (ng/1)

                           Fig. 10. Concentrations of polynuclear aromatic hydrocarbons, grouped by number
                                        of rings and individually, in Ship Channel seawater samples.








                                                                                                                 39




                       observed decreasing PAH concentrations in seawater with increasing molecular weight is

                       consistent with published solubility data (e.g. Whitehouse, 1984). The distribution of

                       PAHs by ring numbers in oyster tissues showed lower concentrations of five-ring PAHs

                       relative to the surrounding sediments. Compared to the seawater PAH distribution, oyster

                       tissues were depleted in the more soluble two- and three-ring aromatic hydrocarbons. The

                       PAH distribution for oysters is intermediate when compared to sediments and seawater.



                       Depuration of PAHs by Newly and Chronically Contaminated Oysters

                           Average concentrations of selected PABs measured in HRSCHR and SCHR oyster

                       and sediment samples from the Hanna Reef area are shown in Table A-4 and A-5

                       (Appendix). Sediment concentrations were normalized by dividing by the percentages of

                       silt and clay in the samples to decrease the variability observed among the samples. After

                       relocation to the Hanna Reef area, HRSCHR and SCHR oysters showed statistically

                       significant depuration of accumulated PAHs. At the end of the depuration period, the total

                       PAH concentrations in HRSC oysters were about 40% higher than the final

                       concentrations in HRSCHR individuals in the same period of time. Total PAH
                       concentrations decreased from 4,400 to 360 ng g-1, in HRSCHR oysters, and from
                       4,400 to 500 ng g-1, in SCHR oysters. In both cases, most of the decreases in

                       concentrations were due to the depuration of four- and five-ring PAHs (Fig. 11). The

                       diffences in the final concentrations of some individual three-, four- and five-ring

                       hydrocarbons between SCHR and HRSCHR oyster populations at the end of the 50-day

                       depuration period are evident (Fig. 12). The largest percent differences were observed for

                       fluoranthene (38%), pyrene (70%), chrysene (80%) and benzo(e)pyrene (I 10%).

                           Although HRSCHR and SCHR oysters significantly depurated most of the

                       bioaccumulated individual PAHs, their concentrations did not decrease to the levels

                       encountered for HR oysters at the begining of this study. For example, Fig. 13 shows







                                                                                                                                                                                   40





                                                 Hanna Reef Site - 0 day                                                   Hanna Reer Site       IS days
                                          4000"                                                                     4000'
                                                                               a Hopes Reer Oysters                                                      0 Hansa RedOysteri
                                                                                  Ship Channel Oysters                                                   0 Ship Channel Oysters

                                                                                                                    3000'
                                    In



                                          2M -                                                                      2000




                                          low                                                                       1000



                                                                                                Man-                    0.
                                                     2            3           4         S            6                          2          3          4            5          6
                                                                   Number of Rings                                                            Number of Rings
                                                 Hanna Reef Site - 3 days                                           4000-  Hanna Reer Site       30 days
                                                                                                                                                         a Boons Reef Oysters
                                                                               U Hansa Reef Oysters
                                                                               6 Ship Channel Oysters          it                                        M Ship Channel Oysters
                                                                                                                    3000'
                                          39W                                                                  V


                                          2000-                                                                5    2000-.
                                                                                                               C



                                                                                                                    1000-
                                          1000,



                                                     2            3           4         S            6                          2          3          4            S          6
                                                                    Number of Rings                                                           Number or Rings
                                                 Hanna Reef Site - 6 days                                                 Hanna Reef Site       50 days
                                                                               a Fianna RecrOysters                 4000.,                               M Hansa Reer Oysters
                                                                               0 Ship Channel Oysters          It                                        0 Ship Channel Oysters

                                    A.    30M                                                                       3w
                                    V                                                                          V


                                                                                                               at
                                          2M.                                                                       2000




                                    0
                                          low"


                                    L)                                                                         Ld

                                                     2           a            4         3            6                          2          3          4            5          6
                                                                   Number of Rings                                                            Number of Rings


                                        Fig. 11. Concentrations of polynuclear aromatic hydrocarbons, grouped by number
                                      of Tings, in back-transplanted Hanna Reef and transplanted Ship Channel oysters during
                                                                  the 50-day depuration period in the Hanna Reef area.







                                                                                                                          41









                                           Naphthalene
                                   2-Methylnaphthalene
                                   I-Methyinaphthalene
                                              Biphenyl
                               2,6-Dimethylnaphthalene
                                        Acenaphthylene
                                          Acenaphthene
                            2,3,5-Trimethylnaphthalene
                                              Fluorene

                                          Phenanthrene

                                            Anthracene
                                 I-Methylphenanthrene
                                          Fluoranthene

                                                 Pyrene
                                     Benz(a)anthracene
                                              Chrysent
                                  Benzo(b)fluoranthene
                                  Benzo(k)fluoranthene
                                        Benzo(e)pyrene
                                        Benzo(a)pyrene
                                              Perylene                                     Ship Channel Oysters
                                Indeno[1,2,3-c,d]pyrene                                    Hanna Reef Oysters
                                 Dibenz(a,h)anthracene
                                    Benzo(g,h,I)perylene

                                                        0           50          100          150          200

                                                                  Concentration (ng/g, dry wt.)


                         Fig. 12. Concentrations of individual polynuclear aromatic hydrocarbons in tissues of
                            Hanna Reef and Ship Channel oysters at the end of the 50-day depuration period.








                                                                                                                             42)





                                                              2

                                                              3

                                                              4
                                                    E           . . . . . . .......... ...
                                                              6
                                                   z                        . . . . . . . . . . . . . . . .
                                                              0         so         1@0         1;0       2@0         2;0

                                                Naphthalene
                                        2-Methyinaphthalene
                                        1-Methylnaphthaleruie
                                                   Bipbenyl
                                    2,6-Dimetbylnaphthalene
                                             Acenaphthylene
                                               Acenaphthene
                                  W,S-Trimethylnaphthalene
                                                   Fluorene

                                               Phenanthrene

                                                 Anthracene
                                      I-Methylphenanthrene
                                               Fluoranthene

                                                      Pyrene
                                          Benz(a)anthracene
                                                   Chrysene
                                       Benzo(b)fluoranthene
                                       Benzo(k)fluoranthene
                                             Benzo(e)pyrene
                                             Benzo(a)pyrene
                                                   Perylene                                      Before Transplantation
                                     Indeno[I,2,3-c,dlpyrene
                                      Dibenz(a,h)anthracene                                      After Depuration
                                        Benzo(g,h,i)perylene

                                                              0     20      40     60      80     100     120    140

                                                                        Concentration      (ng/9, dry wt.)

                               Fig. 13. Comparison of the concentrations of polynuclear aromatic hydrocarbons,
                              grouped by number of rings and individually, in tissues of Hanna Reef oysters before
                             exposure to the Ship Channel contaminant levels and after depuration at the Hanna Reef
                                                                           si te.







                                                                                                                  43




                        the concentrations of PAHs, according to the number of rings and individually, in Hanna

                        Reef oysters before transplantation to the contaminated site and after depuration for 50

                        days at the Hanna Reef site. The original distribution of PAHs in Hanna Reef oysters

                        showed a predominance of the more volatile and soluble compounds, i.e. two- and three-

                        ring PAHs. When these oysters were exposed to higher PAH concentrations at the Ship

                        Channel area, they bioconcentrated four- and five-ring PAHs. This resulted in higher

                        concentrations for total PAHs as well as in a different distribution of PAHs when the

                        oysters were back-transplanted to the Hanna Reef location. These different distributions

                        are probably the consequences of two different sources of PAHs. In the first case, the

                        PAH distribution reflects the remote location of the Hanna Reef site and indicates

                        atmospheric inputs and water transport of the more soluble PAHs as their most probable

                        sources. A slight increase in the concentration of naphthalenes with time in SCHR and

                        HRSCHR oysters during the depuration part of this study was observed. When oysters

                        are exposed to the significantly higher PAH concentrations, over a wider molecular

                        weight range, present in the Ship Channel area, they readily bioconcentrate the higher

                        molecular weight PAHs. Because of the low water solubility of the predominant

                        compounds encountered in Ship Channel oysters, it is probable that the main route of

                        uptake is through food ingestion. In contrast, most of the uptake in the Hanna Reef area

                        probably occurs through gills. Unfortunately, the concentrations of PAHs in Hanna Reef

                        water samples were below the detection limit; therefore, no firm conclusion can be drawn.

                            Sediment samples collected from the Hanna Reef area had a distribution of PAHs, by

                        zing numbers, similar to that encountered near the Houston Ship Channel; however, the

                        concentrations of individual PAHs were about an order of magnitude lower (Fig. 14).

                        With the exception of the high concentration of perylene, a compound with natural as wen

                        as combustion sources, in Hanna Reef sediments, the differences in concentrations









                                                                                                                            44






                                                          2

                                                          3

                                                          4



                                                          6
                                                    z
                                                            0            so            1 00           ISO          200



                                                Naphthalene
                                       2-Nlethylnaphthalene
                                        1-Methyinaphthalene
                                                   Biphenyl
                                   2,6-Dimethylnaphthalene
                                             Acenaphthylene
                                              Acenaphthene
                                 2,3,5-Trimethyinaphthalene
                                                   Fluorene

                                               Phenanthrene      ......

                                                 Anthracene
                                      I-Methylphenanthrene
                                               Fluoranthene
                                                     Pyrene
                                          Benz(a)anthracene
                                                   Chrysene
                                       Benzo(b)fluoranthene
                                       Benzo(k)fluoranthene
                                             Denzo(e)pyrene
                                             Benzo(a)pyrene
                                                   Perylene                                       . ......
                                     1ndeno[I,2,3-c,djpyrene
                                      Dibenz(a,h)anthracene
                                        Benzo(g,hJ)perylene

                                                            0          20         40          60         so         100

                                                                       Concentration (ng/g, dry wt.)

                           Fig. 14. Concentrations of polynuclear aromatic hydrocarbons, grouped by number
                                         of rings and individually, in Hanna Reef sediment samples.







                                                                                                                        45




                         between the lower and higher molecular weight PAHs in these samples is less marked

                         than in the case of the Ship Channel sediment samples.

                             Clearance rates of aromatic compounds by both groups of oysters were approximately

                         exponential. This is indicated in Fig. 7 where the concentrations of selected PAHs,

                         during the depuration phase of this study, plotted on semi-log plots, approximate straight

                         lines. Original Hanna Reef oysters depurated PAHs at a faster rate than Ship Channel

                         oysters. Differences in the slopes of the depuration curves are reflected in the lower PAH

                         half-lives for SCHR oysters. Calculations to estimate the half-lives and related kinetic

                         parameters for the different trace organic pollutants by Crassostrea virginica oysters will

                         be discussed in more details in Chapter VI. The depuration half-lives for PAHs ranged

                         from 9 to 24 days and from 10 to 24 days in originally uncontaminated Hanna Reef and

                         chronically exposed Ship Channel oysters, respectively. Most of PAH half-lives were

                         between 10 and 13 days and 13 and 16 days for HRSCHR and SCHR oysters,

                         respectively. These values are within the ranges of previously reported PAH half-lives

                         (Table 2). A few studies report complete depuration of PAHs by bivalves after they are

                         relocated to a clean environment over short periods of time (less than a week). However,

                         the reported minimum detection limits for PAHs in those studies were generally high. For

                         example, Pittinger et al. (1985) reported minimun detection limits for PAHs ranging from
                         93 to 222 ng g-l. If those minimum detection limits are applied to this study, most of the

                         measured PAHs, in both groups of oysters, would be below detectable levels after one

                         week of relocation to the Hanna Reef area.




                         CONCLUDING REMARKS



                             PAHs were rapi   dly accumulated by uncontaminated oysters to final concentrations that

                         were statistically undistinguished from the concentrations encountered in indigenous Ship








                                                                                                                           46








                                                                      TABLE 2
                              Biological Half-Lives (Days) of PAHs in Hanna Reef and Ship Channel Crassostrea virginica
                                                                       Oysters.


                             Analyte                      Hanna         Ship     Dun & Stich      Lee et al. Pruell et al.
                                                            Reef      Channel       (1976)         (1978)      (1986)
                                                          Oysters     Oysters      Mussels         Oysters     Mussels


                             2,3,5-Trimethyinaphthalene      24           22            -              -
                             Anthracene                      24           42            -              3
                             I-Methylphenanduene             23           24            -              -            -
                             Huoranthene                     26           3 '1          -              5          30
                             Pyrene                          10           12            -              -            -
                             Benz(a)andiracene               13           15            -              9          18
                             Chrysene                        12           16            -              -          14
                             BenzoNfluoranthene                                         -              -          17
                             Benzo(k)fluoranthene                                       -              -          12
                             Benzo(e)pyrene                  12           16            -              -          14
                             Benzo(a)pyrcne                    9          10           16             18          15
                             Perylene                        11           13            -              -            -
                             Indeno[ 1.2,3-c.d]pyrene        10           11            -              -          16
                             Dibenz(ab)anthracene            16           14            -              -
                             Benzo(g,h,i)perylene            11           12            -              -          15








                                                                                                                   47




                        Channel oysters within 20 to 25 days after transplantation. The PAHs accumulated to the

                        highest concentrations in SC and transplanted HRSC oysters were: pyrene > fluoranthene

                        > chrysene > benzo(e)pyrene > benzo(a)anthracene. Although there are some

                        discrepancies when comparing the order of uptake of these PAHs, encountered in the

                        present study, with previously published works using different bivalves, these

                        discrepancies might reflect the different PAH compositions in the sources or a different

                        uptake ability of the organisms. Ile final distributions of individual PAHs in transplanted

                        and indigenous oysters during the uptake phase of this experiment were intermediate

                        between the profiles encountered in sediment and seawater samples from the Ship

                        Channel area.

                            When transplanted to the relatively uncontaminated Hanna Reef area, both groups of

                        oyster depurated the bioaccumulated PAHs. Calculated depuration rates were higher for

                        the originally uncontaminated oysters. Most of individual PAH deputation half-lives were

                        between 10 and 13 days and 13 and 16 days for HRSCHR and SCHR oysters,

                        respectively. The depuration of individual PAHs by HRSCHR oysters was, however,

                        not complete and the concentrations encountered at the end of the depuration period were

                        higher than the levels measured before their exposure to the Ship Channel concentrations.

                        Comparing the distribution profiles of PAHs encountered in HRSCHR oysters at the end

                        of the depuration period with the distribution they had before the transplant experiment,

                        i.e. HR oysters, seems to indicate that the sources of PAHs to Hanna Reef and Ship

                        Channel are different. While the original distribution of PAHs in Hanna Reef oysters

                        showed a predominance of the more volatile and soluble compounds, i.e. two- and three-

                        ring PAHs, the distribution of PAHs after the  deputation phase of this experiment shows

                        predominance of four- and five-ring PAHs. It can be speculated that petroleum

                        background and water transport are the most probable sources for the predominance of the

                        lower molecular weight PAHs to the Hanna Reef area.








                                                                                                                    48












                                                                 CHAPTER III




                            UPTAKE, RETENTION AND RELEASE OF PCBs BY THE AMERICAN OYSTER

                                                       (CRASSQSTREA VIRGINICA



                           INTRODUCTION



                              Polychlorinated biphenyls (PCBs) are of particular concern in pollution studies

                           because of their widespread occurrence, environmental persistence and bioaccumulation

                           properties. For these reasons, these compounds have been included as analytes of interest

                           in many national and international programs (see, for example, Farrington et al., 1980;

                           Sericano et al., 1990a). In most of these monitoring programs, bivalves were preferTed

                           as sentinel organisms.

                              Despite the overwhelming popularity that the "Mussel Watch" concept has obtained

                           since its introduction in the 1970s, both monitoring data and, particularly, laboratory-

                           generated data on PCB kinetics in bivalves show discrepancies. For example, there are

                           disagreements over which PCB congeners are preferentially accumulated by bivalves and

                           the length of time bivalves need to reach an equilibrium with environmental concentrations

                           or the time needed for different PCB congeners to be depurated, if they are depurated,

                           when the environmental concentration is reduced. Such inconsistencies decrease the

                           usefulness of the Mussel Watch concept in environmental studies.

                              This chapter reports the uptake and release of PCBs by two groups of American

                           oysters (Crassostrea virginica) with different pollution histories. Oysters from Hanna







                                                                                                                  49



                         Reef, a relatively uncontaminated area in Galveston Bay, were transplanted to a site near

                         the Houston Ship Channel, a highly polluted area, to assess the accumulation of PCBs

                         over a period of seven weeks. . Concentrations in transplanted oysters were compared to

                         the levels encountered in indigenous Ship Channel oysters. After the uptake period, the

                         remaining Hanna Reef oysters were back-transplanted to their original geographic location

                         to monitor the depuration of the bioaccumulated organic contaminants. At the same time,

                         indigenous Ship Channel oysters were transplanted to the Hanna Reef area in order to

                         compare depuration rates of PCBs between the two groups of oysters, i.e. newly and

                         chronically contaminated.



                         PCBs: A REVEEW



                         Background Information

                            PCBs are the subject of several monographs and books (e.g. Safe, 1984; Erickson,

                         1986; Safe et al., 1987; Tanabe & Tatsukawa, 1986; Voogt & Brinkman, 1989; Lang,

                         1992). Polychlorinated biphenyls (PCBs), systematically called 1,1'-biphenyl, chloro

                         derivatives, is the generic name of many isomers and congeners with I

                         (monochlorobiphenyls) to 10 (decachlorobiphenyl) chlorine atoms substituted on both

                         biphenyl rings (Fig. 15). The synthesis of PCBs was first described by Schmidt &

                         Schultz (1881); however, commercial production in the U.S.A. did not begin until 1929.

                         The rings in the biphenyl molecule are joined by a single carbon-carbon bond allowing

                         free rotation of both rings. The presence of one or more chlorine in ortho positions (2,

                         2', 6 and/or 6') results in an inter-ring angle of up to 90' (McKinney et al., 1983).

                         Although there are 209 possible PCB congeners, the catalytic electrophilic substitution of

                         chlorines is favored at the ortho and para positions on the biphenyl molecule. Thus,

                         several congeners have been found to be absent (or present at levels below 0.05% total









                                                                        50





                                       PCBS


                                            C12H I O-nC In
                  Cl                        (n-itoio)


                  NomgUgLaLurQ:

                      3 2
                   4G       2- 3- 4'
                      5 6  Q65 -

                 FAMM22 Of M-WQ-r f4g-0192-n em Ln E n vi ro n m e n1a I Ba m4gU:
                      C1  C1           C1  C1        C1 C1      C1
                                   C4@              C4            C1
                                    a         C1
                      PCB #52          PCB #101         PCB #105
                  C1 C1      C1     C1 C1  C1        C1 C1  C1
                  0-0          C1 cl@@C,            C,
                      C,                      C1
                     PCB#110          PCB #138       C1 PCB #180 C1
                Fig. 1S. General formula of polychlorinated biphenyls and exLmples of major
                        congeners commonly found in environmental samples.








                                                                                                              51




                       concentration) from technical PCB mixtures (Schulz et al., 1989). Unique properties,

                       including thermal stability and resistance to oxidation, resulted in the use of PCBs as

                       adhesives, heat transfer fluids, wax extenders, hydraulic fluids, lubricants, flame

                       retardants and as dielectric fluids in transformers and capacitors.

                           Different PCB formulations were graded and marketed according to their chlorine

                       content. Monsanto Chemical Corporation produced, for example, Aroclor 1221, 1232,

                       1254 and 1260, which contained 21, 32, 54 and 60 percent of chlorine by weight,

                       respectively. Many comparable commercial PCB formulations have been produced by

                       different chemical companies in several countries including Kanegafuchi Chemical Co. in

                       Japan (Kaneclor), Prodelec in France (Phenoclor), Bayer in West Germany (Clophen),

                       Deutchen Solvay Werken in East Germany (Orophene), Caffaro in Italy (Fenclor) and

                       Soval in the U.S.S.R. (Sovol and Sovtol) (Onuska & Comba, 1980). It has been
                       reported that between 1930 and 1975 the U.S.A. production of PCB:s was 570xlO3 tons

                       (U.S. Environmental Studies Board, 1979) whereas the total worldwide production of
                       PCBs through 1980 was estimated to be 11 OOx 103 tons (Erickson, 1986). In 1977, the

                       major U.S. producer, Monsanto Chemical Corporation, ceased manufacturing PCBs

                       partly due to their widespread detection in the environment. A recent estimation,

                       however, indicates that more than two-thirds of the cumulative world PCB production

                       may still be in use mainly in older transformers and capacitors (Tanabe, 1985).

                          Dr. Soren Jensen, a Swedish environmental chemist, first reported the presence of

                       several unknown peaks that interfered with quantitative determinations of DDT in

                       environmental samples (Jensen, 1966); those peaks were soon identified as a complex

                       mixture of PCBs by GC and GC/MS (Widmark, 1967). The earliest analyses of PCBs,

                       e.g. before 1980, were performed with packed columns. The results of these studies

                       have provided valuable information on hot spots and general trends in concentration

                       distributions; however, because of the low-resolution chromatograms most of the








                                                                                                                     52




                          information regarding individual congeners, which are important when determining

                          source identification, sink, toxicity and biological uptake or depuration, was limited. The

                          importance of considering individual PCB congeners in view of their differences in both

                          toxicity and physico-chemical properties is well recognized (see, for example, Shaw &

                          Connell, 1984; Opperhuizen et al., 1985, 1988; Tanabe er al., 1987b, 1987c). Although

                          a complete separation of all 209 PCB congeners with a single gas chromatographic run

                          has not been achieved yet, the introduction of the capillary column greatly improved the

                          separation of individual congeners.

                              The synthesis and chromatographic properties of all 209 PCB congeners have been

                          reported (Mullin et al., 1984). Certain PCB congeners are considered to be the most toxic

                          because they can attain a planar stucture similar to the highly toxic dibenzo-p-dioxins and

                          dibenzofurans (McKinney et al., 1976, 1985; Hansen, 1987; McFarland & Clarke,

                          1989). Because of their environmental significance, these PCB congeners will be

                          discused separately in Chapter IV.

                              PCBs are ubiquitous contaminants of the global environment. The physicochemical

                          proper-ties of these components vary widely depending on the number and position of

                          chlorine atoms in the biphenyl rings. In general, vapor pressure, water solubility and

                          biodegradability decrease with increasing number of chlorine atoms, whereas lipophilicity

                          and adsorption capacity show a reverse trend (Tanabe et al., 1984). Large variations of

                          PCB compositions are found in different environmental compartments resulting from this

                          wide range of properties. PCBs have been found in air, water, soil and sediment samples

                          throughout the world (e.g. Atlas & Giam, 198 1; Tanabe et al., 1983a). Nearly all marine

                          plant and animal specimens, fish, mammals, birds (especially fish-eating birds), bird eggs

                          and humans have measurable PCB concentrations (Tanabe et al., 1983b, 1986, 1987c).

                          In general, PCBs are detected in parts per billion (ppb) in organism, soil and








                                                                                                                 53




                        sediment samples and in parts per trillion (ppt) in water samples; however, concentration

                        levels vary over a large range from highly polluted to pristine.



                        Distribution and Occurrence in Galveston Bay

                            A variety of organochlorine residues have been determined in organisms, e.g.

                        bivalves and various species of fishes and birds, sediment and water samples, from the

                        Galveston Bay area. PCB congeners were one of the most commonly found compounds

                        in Galveston Bay samples (Table 3).

                            The ubiquity of PCBs in Galveston Bay was demonstrated by Fox (1988). Oyster

                        samples were collected from four different sites. PCBs were detected in every sample

                        analyzed during the study. Concentrations measured in oysters collected near the

                        Houston Yacht Club were higher than the levels found in samples from Hanna Reef,

                        Todd's Dump and Confederate Reef areas.

                            A number of different species of fish were also analyzed for PCBs. Concentrations

                        ranged over two orders of magnitude. Finfishes such as mullet, croaker and Florida

                        pompano, collected in the vicinity of a power plant (Houston Lighting and Power

                        Company) near the upper Trinity Bay, contained PCB concentrations in the range of 50-
                        500 ng g- I (Strawn er al., 1977). Lower concentrations were reported in juvenile
                        croakers (9-43 ng g-1; Stahl, 1980). Similar ranges to those published by Strawn et al.

                        (1977) were reported for tidewater silverside, sheepshead minnow and striped mullet

                        (King, 1989a, 1989b). These fishes are the food source of some birds such as black

                        skimmer and olivaceous cormorant.

                            A few waterbirds, e.g. olivaceous and double-crested cormorants, laughing gulls and

                        black skimmers, nesting in the upper Galveston Bay were also analyzed for chlorinated

                        hydrocarbons (King & Krynitsky, 1986; King et al., 1987). Average concentrations and

                        concentration ranges encountered in these birds were similar.             PCB average
















                                                                                                TABLE 3
                        Polychlorinated Biphenyl Concentrations in Samples from the Galveston Bay Area. Except Where Indicated, Concentrations in Organisms Are
                           Expressed in ng g-1 on a Wet-Weight Basis. Concentrations in Sediment and Water Samples Are Expressed in ng g-I, on a Dry-Weight
                                                                                   Basis, and in ng 1-1, Respectively.


                        Location                           Sample                        PCBs                            Range                              Reference

                        Yacht Club                         oysters                         966                       120-4,025                        Fox, 19880)
                        Todd's Dump                        oysters                         155                        47.4-283                        Fox, 19880)
                        Confederate Reef                   oysters                         131                         94.7-171                       Fox, 19880)
                        Hanna Reef                         oysters                       59.4                          32.5-107                       Fox, 19890)
                        Trinity Bay                        fish                                                          50-160                       Strawn et al., 1977
                                                           fish                                                          50-500                       Strawn el al., 1977
                                                           fish                                                          60-150                       Strawn et al., 1977
                        Galveston Bay                      fish                                                             9-43                      Stahl, 1980
                                                           crab                                                            18-42
                        Galveston Bay                      fish                            310                           70-540                       King, 1989a(2)
                        Galveston Bay                      fish                            350                          100-620                       King, 1989b(2)
                        Galveston Bay                      cormorants                    6,990                    2,600-24,000                        King & Krynitsky, 1986(2)
                                                           gulls                         4,210                    1,500-11,000
                                                           skimmers                      3,880                      800-11,000
                        Galveston Bay                      cormorants                    1,580                      1,100-3,300                       King et al., 1987(2)




                                                                                          MM










                                                                                                 TABLE 3
                                                                                                 (continued)





                        Location                            Sample                        PCBs                             Range                              Reference


                        Houston Ship Channel                sediments                     3,250                                                         Salch & Lm 1976
                        Texas City Channel                  sediments                     2,860                                                         Salch & Lee, 1976
                        Galveston Bay                       sediments                                                       15-68                       Stahl, 1980
                        San Luis Pass                       sediments                       0.52                      0.25-0.78                         Murray et al., 1981 a
                        Morgan's Point                      sediments                       1.5                       <0. 14-3.3                        Murray et al., 198 1 b
                        Trinity 'Bay                        sediments                       1.2                       <0. 14-7.1                        Murray et al., 198 1 b
                        Texas City Channcl                  sediments                       2.8                       <0. 14-5.6                        Murray et al., 19 8 1 b


                        Galveston Bay                       water                                                            2-15                       Stahl, 1980
                        Morgan's Point                      water                           1.1                       <0.0 1 -4,6                       Murray et al., 198 1 b
                        Trinity Bay                         water                           1.8                       <0.0 1 -4.1                       Murray et al., 198 1 b
                        Texas City Channel                  water                             18                       <0.0 1 -70                       Murray et al., 198 lb

                        n.d.= not detected; (1) ng g- 1 on a dry-weight basis; (2) geometric mean








                                                                                                                  56



                          concentrations ranged from 1,580 to 6,990 ng g-1, respectively. These concentrations are

                          one order of magnitude higher than concentrations listed on Table 3 for Galveston Bay

                          fish samples. Since these fish-eating birds are at the top of an aquatic food chain, a

                          bioaccumulation of organic contaminants is seen. With overall average PCB
                          concentrations of 4,170 ng g-1 in waterbirds and 330 ng g-1 in fishes, a biaccumulation

                          factor of 13 can be calculated for PCB; residues in Galveston Bay waterbirds.

                             Reports of PCB   s concentrations in sediment and water samples from the Galveston

                          Bay area are limited. In general, PCB concentrations in sediments were in the <0.14 to
                          7.1 ng g- I range (Murray et al., 1981, 1981 b). Stahl (1980) reported a slightly higher
                          concentration range for PCBs in sediments (15-68 ng g- 1). These concentrations are two

                          to three orders of magnitude lower than those previously reported in dredged sediments

                          from the Houston Ship and Texas City Channels (Saleh & Lee, 1976). The samples

                          collected during that study corresponded to sediments disturbed by the construction of

                          underwater pipelines; therefore, they might represent sediments deposited before the

                          restrictions of the use of PCBs in the U.S.A. in the 1970s. Water samples collected at

                          different locations in Galveston Bay had PCB concentrations ranging from <0.01 to 70
                          ng 1-1 (Saleh & Lee, 1976). The higher PCB concentrations were measured near Texas

                          City.



                          Bivalve Uptake and Depuration Studies

                             There are published works reporting uptake and depuration of PCBs by a variety of

                          organisms; however, the number of studies involving bivalves are limited. The methods

                          generally used to expose bivalves to PCB congeners in the laboratory (e.g. Lowe et al.,

                          1972; Vreeland, 1974; Courtney & Denton, 1976; Pruell et al., 1986, 1987) are similar to

                          those mentioned for petroleum hydrocarbon exposures (Chapter II). Transplanting

                          bivalves from an uncontaminated area to contaminated areas or vice versa has also been








                                                                                                                   57



                         done in uptake and depuration studies (e.g. Calambokidis et al., 1979; Tanabe et al.,

                         1987a; Kannan et al., 1989; Sericano et al., in press).

                            In a laboratory study with blue mussels (Mytilus edulis) exposed to contaminated

                         sediments, Pruell et al. (1986) reported an equilibration time of about 20 days for four

                         PCB congeners although this bivalve failed to accumulate the highly chlorinated

                         congeners present in the exposure sediments after a 40-day exposure period. Sin-dlar time

                         scales were reported for the uptake of the lower molecular weight PCB congeners, i.e.

                         those congeners having 2, 3 or 4 chlorines in the molecule, by transplanted green-lipped

                         mussels (Perna viridis) in contaminated Hong Kong waters (Tanabe et al., 1987a).

                         Lower equilibration rates, i.e. more time, for high er-chlorinated PCB congeners are

                         reported. Vreeland (1974) suggested that, even after an equilibrium with the PCB

                         congener concentrations is attained, the total amount of PCB per oyster increases as the

                         oyster grows. Langston (1978) observed some differences in the depuration rates of

                         selected PCB congeners by bivalves (Cerastodernia edule and Macoma balthica). Di-, ni-

                         and tetrachlorobiphenyls, with half-lives ranging from 5 to 21 days, were depurated faster

                         than hexachlorobiphenyls and some pentachloro-biphenyls.                  Most of the

                         hexachlorobiphenyls did not show any decrease after 21 days. Pruell et al. (1986)

                         reported that about 50% of the total PCBs accumulated by exposed blue mussels (Mytilus

                         edulis) were lost after 40 days in clean seawater with half-lives for tri- to

                         hexachlorobiphenyls ranging from 16.3 to 45.6 days. Contrasting with this study,

                         Courtney & Denton (1976) reported that clams exposed to a PCB mixture, Aroclor 1254,

                         in the laboratory did not depurate the accumulated PCBs during a three-month period in

                         control seawater.








                                                                                                                    58




                          UPTAKE AND DEPURATION OF PCBs



                          Experimental Design, Sample Collection and Methods

                             The experimental design and sample collection used for the study of PCBs were the

                          same as those discussed for PAHs (Chapter II).



                          Ejaraction and saVlefiractionation of PCBs

                             As described in the previous Chapter, the analytical procedure used in the extraction,

                          fractionation and cleanup of PCBs in oyster, sediment and water samples, which is done

                          concurrently with the extraction, fractionation and cleanup of PAHs (Fig. 5, Chapter II),

                          was based on a method developed by MacLeod et al. (1985) with a few modifications that

                          proved to be equivalent or superior to the original technique. The important steps of this

                          method have been previously discussed for PAHs. The only differences for PCB

                          analysis are:

                             a.    PCB congener quantitations were done using 4,4 dibromoocta-fluorobipbenyl

                          (DBOFB) and PCBs congeners 103 and 198 as internal standards. As previously

                          discussed, these standards were added at concentrations similar to those expected in the

                          samples for the compounds of interest.

                             b.    After the final extract concentration to I ml, and before the addition of the GC

                          internal standard for GC-ECD analysis, a 250 ul fraction was reserved for further planar

                          PCB analyses.



                          Instrurwntal analysis
                             PCB  s were analyzed by fused-silica capillary column GC-ECD (Ni63) using either a

                          Varian 3500 GC or a Hewlett Packard 5880A GC in the splitless mode. Capillary

                          columns, 30 meters long x 0.25 mm i.d. with 0.25 mm DB-5 film thickness, were








                                                                                                                     59



                         temperature-programmed from 100 to 1401C at 5'C min- 1, from 140 to 250'C at 1.5*C
                         min- I and from 250 to 3001C at I O'C min-1 with I min hold time at the beginning of the

                         program and before each program rate change. A hold time of 5 min was used at the final

                         temperature. Total run time was 94.33 min. Injector and detector temperatures were set

                         at 275 and 325)C, respectively. Helium was used as carrier gas at a flow velocity of 30.0
                         cm sec-1 at 1000C. Nitrogen or argon/methane (95:5) were used as make-up gases at a
                         flow rate of 20 ml min-1. The volume injected was 2 gl. The numbering of PCB

                         isomers, after Ballschmiter & Zell (1980), is as follows: numbers 1-3 represent mono-, 4-

                         15 di-, 16-39 tri-, 40-81 tetra-, 82-127 penta-, 128-169 hexa-, 170-193 hepta-, 194-2Q5

                         octa-, 206-208 nonachlorobiphenyls and 209 decachloro-biphenyl. A group of PCB

                         congeners (i.e. 8, 18, 28, 44, 52, 66, 101, 105, 110, 118, 128, 138, 153, 170, 180,

                         187, 195, 206 and 209) were quantitated against a set of authentic standards, which were

                         injected at four different known concentrations to calibrate the instrument and to

                         compensate for non-linear response of the electron capture detector. The remaining PCB

                         congeners were quantitated by comparison to a single reference congener of the same

                         degree of chlorination injected at four different known concentrations. The reference PCB

                         congeners used for quantitation were 8, 28, 52, 101, 138, 170, 195, 206 and 209 for di-,

                         tri-, tetra-, penta-, hexa-, hepta-, octa-, nonachlorobiphenyls and decachloro-biphenyl ,

                         respectively. Tetrachloro-m-xylene (TCMX) was used as the GC internal standard to

                         calculate the recoveries of the internal standards. The detection limits for organochlorines

                         and individual PCB isomers, calculated on the basis of 15 g (wet weight) tissue and 50 g

                         (wet weight) sediment sample sizes with 0.2% by volume of the extract injected into the
                         GC-ECD, were 0.25 and 0.02 ng g- I dry weight for oysters and sediments, respectively.








                                                                                                                    60



                          AncilLarypararneters

                              Methodologies for the sediment grain-size analysis and extractable lipids percentage

                          were discussed in the materials and methods section of Chapter II.



                          SwistictV wialysis

                              The statistical analyses performed on the PCB data were previously discussed in the

                          materials and methods section of Chapter Il.



                          Uptake of PCBs by Transplanted Oysters

                              In the following sections, Ship Channel, Hanna Reef, transplanted Hanna Reef-to-

                          Ship Channel, transplanted Ship Channel-to-Hanna Reef and relocated Hanna Reef-to-

                          Ship Channel-back to-Hanna Reef oysters are refered as SC, HR, HRSC, SCHR and

                          HRSCHR oysters, respectively.

                              Average concentrations of the predominant PCB congeners found during the first part

                          of this experiment in SC and HRSC oyster, sediment and water samples are reported in

                          Tables A-6 and A-7 (Appendix). Total PCB concentrations in indigenous Ship Channel

                          oysters were fairly constant during the seven-week uptake period with values fluctuating
                          between 960 and 1,500 ng g-1. In contrast, concentrations of total PCBs in transplanted
                          HRSC oysters increased from 30 ng g- I to 830 ng g- I after the 48-days exposure period

                          to the Ship Channel conditions. Typical PCB chromatograms of extracts obtained from

                          transplanted HRSC oysters during the uptake phase of this study are shown in Fig. 16.

                              Pentachlorobiphenyls accumulated to the highest concentrations in HRSC and native

                          SC oysters (Fig. 17). In comparison, practically no octa-, nona- or decachloro-biphenyls

                          were de tected in either oyster group. Not all the PCB homologs measured in transplanted

                          oysters reached the concentration encountered in indigenous individuals by the end of the

                          first phase of this experiment. While there were not statistically significant differences









                                                                                                              61






                                                                                      HRSC-3


                                                                                 UL   HRSC-7


                                                                                      HRSC-17












                                                                                     HRSC-30
                                                                          ux't@







                                                                                     HRSC-48



                         Fig. 16. Examples of high-resolution gas chromatograms of Hanna Reef oysters
                        transplanted to the Ship Channel area during different stages of the 48-day exposure
                          period. PCB congeners are numbered according to Balischmitter & Zell, 1980.








                                                                                                                                                                                   62





                                                 Ship Channel Site        0 day                                            Ship Channel Site       17 days
                                            100                                                                      low
                                            "o                                   0 Henna Reer Oysters                                                    0 Ban" Red Oysters
                                                                                 N Ship Channel Oysters                                                  0 Ship channel Oysters
                                            we                                                                       W

                                     V      700                                                                      700

                                                                                                                     60

                                            SM                                                                       Soo

                                            MW                                                                       40
                                            me                                                                 Z'    3W
                                                                                                               C

                                     C                                                                         r
                                            Soo                                                                      100

                                              0                                                                          0
                                                   1 2 3 4 S 6 7 8 9 10                                                      1 2 3 4 5 6 7 8 9 10

                                                                 Level of Chlorination                                                     Level of Chlorination
                                            1000 Ship Channel Site - 3 days                                          1000  Ship Channel Site - 30 days
                                                                                 E Henna Reer Oysters          -                                         M Hones Reer oysters
                                     -r     9W                                                                       900
                                                                                 0 Ship Channel Oysters        It                                        0 SbIpChaosel Oysters
                                            Soo                                                                      so
                                            700                                                                      700
                                            GN                                                                 at    600
                                            Sail                                                                     Soo
                                     0      400                                                                      400
                                            300                                                                      300
                                                                                                                     200
                                     W
                                                                                                                                           A
                                            100                                                                      100
                                     U        0                Idah                Ak                                    0            AFAM            X.T.In
                                                   1 2 3 4 5 6 7 3 9 10                                                      1 2 3 4 5 6 7 a 9 10
                                                                 Level or Chlorination                                                     Level  of   Chlorination

                                                 Ship Channel Site        7 days                                           Ship Channel Site       48 days
                                            1000                                 a Hanna RetrOysters                 1000                                a Hansa Reeroysters
                                                                                                                     900
                                                                                 0 ship Channel oysters        It                                        2 Sbipchaeftel oysters
                                            $00

                                     V      700                                                                      700
                                     t      600                                                                      600
                                                                                                                     SOD
                                     0      400                                                                Cc    400
                                     Z
                                            300                                                                      300

                                            200                                                                      200

                                            100                                                                      100

                                              0                                                                          0
                                                   1    2     3     4     5      6   7     8     9    10                     1    2     3    4     5     6     7     8    9    10

                                                                 Level or Chlorination                                                     Level or Chlorination


                                            Fig. 17. Concentrations of polychlorinated biphenyl congeners, grouped by level of
                                            chlorination, in transplanted Hanna Reef and indigenous Ship Channel oysters during
                                              the 48-day exposure period near the Houston Ship Channel. Ship Channel Oysters
                                                                                        were not sampled on day 7.
                                               L                                                                         L








                                                                                                                     63




                         (alpha = 0.05) in the total tri- and tetrachlorobiphenyl concentrations measured in HRSC

                         and SC oysters, significant differences were observed in the total concentrations of penta-

                         and hexachlorobiphenyls. Concentrations of these two homolog groups in transplanted

                         HRSC oysters, at the end of the uptake period were about 30 and 50% lower than the total

                         concentrations measured in indigenous SC oysters, respectively.

                             Uptake and depuration curves observed for different PCB congeners are shown in

                         Fig. 18. Some of these represent coeluting congeners, for example PCBs 101 and 90 or

                         PCBs 110 and 77. However, the first congeners listed, i.e. 101 and 110, would be

                         expected to be highly dominant over the others. For example, in one of the most common

                         PCB mixtures, Aroclor 1254, the contribution of the PCB congener 101 to the total

                         101/90 peak is close to 90%; similarly, PCB congener 110 contributes almost 100% of

                         the total 110177 peak (Schulz et al., 1989). Therefore, it is assumed that the uptake and

                         depuration curves represent the first PCB congener; although all the co-eluting congeners

                         are indicated. When comparing the concentrations of individual PCBs measured in

                         transplanted and indigenous oysters after about one month of exposure, the concentrations

                         of the lower-chlorinated congeners, i.e. tri- and tetra- chlorinated biphenyls, in HRSC

                         oysters were similar to the levels encountered in indigenous individuals

                             Although increasing trends in the concentrations of all the predominant PCB

                         congeners were observed in HRSC oyster tissues, the concentrations of the higher-

                         chlorinated biphenyls, i.e. penta-, hexa- and heptachlorobiphenyls, did not always

                         reached full equilibrium with the levels measured in SC oysters. This results in qualitative

                         as well as quantitative differences between the PCB profiles in HRSC and SC oyster

                         samples at the end of the exposure period. The total PCB concentration at the end of the
                         exposure period in HRSC oysters (830 ng g-1) was about 25% lower than the levels
                         encountered in SC oysters (1,100 ng g-1). This is clearly shown in Fig. 19 where the

                         concentrations of selected PCB congeners measured at the end of the seven-week uptake















                                     2,4,4' Trichlorobiphenyl (IUPAC No 28)                                   2,21,4,51 Tegrachlorobiphenyl (FUPAC No 49)




                            V


                                                                                                    628

                            C



                            C
                            owl                                          Hanna Red oysters                                                        Hanna Reef Oysters
                                                                                                                                                  Ship Channel Oysters
                                                                         Ship Channel Oysters
                                                                                                    U


                                     a   Ill   24   30    40    56   60    79   Of     90  too               0    Ill  20    30    46    50   60    70    so   90    too

                                                           Time (days)                                                              Time (days)

                                     2,21,5,51 Tetrachlorobiphenyl (IUPAC  No 52)                              2,31,41,5 Tetrachlorobiphenyl (IUPAC No 70)




                                                                                                          foo.
                            V                                                                        V



                                                                                                           10




                                                                         flanna Reef Oysters                                                       Hanna Reef Oysters
                                                                         Ship Channel Oysters                                                      Ship Channel Oysters
                            U

                                     0   Is    20   30    40    58   60    79   so     90  too               0     to   20    30   40    50    60    1@   as    to   too

                                                           Time (days)                                                               Time (days)


                          Fig. 18. Concentrations of selected polychlorinated biphenyl congeners in tissues of Hanna Reef and Ship Channel oysters
                                   during exposure to the Ship Channel area contaminant levels and following transplant to the Hanna Reef area.









      Montilla












                                                  2,4,4',S Tttrachlorobiphenyl        (TUPAC No 74)                                             2,2',4,5,5' & 2,2',394',S Pentachlorobiphenyis
                                           100                                                                                            1000  (IUPAC No 101 & 90)



                                                                                                                                           too




                                                                                                                                            10

                                                                                                                                     .2
                                                                                                                                     I;


                                                                                                Ilanna Reef Oysters                                                                            Hanna Reer Oysters
                                                                                                                                     c
                                                                                                Ship Channel Oysters                 0                                            :   ,        Ship Channel Oysters
                                     U                                                                                               U

                                                 0     10     20     30     40      so     60     70      80      90    too                   0      to     20     30      40     so     60      ?o     so     90     1 0

                                                                              Time (days)                                                                                   Time (days)
                                                  2,3,3',4',6 Pentachlorobiphenyl (IUPAC No 110) &                                               2,3',4,4'S Pentachlorobiphenyl (IUPAC No 118)
                                           1000.  3,3'4,4' Teirachlorobiphenyl        (IUPAC N.) 77)                                       1000.



                                                                                                                                            fool



                                     cc                                                                                              w
                                     -S                                                                                                      10
                                     C
                                                                                                                                     .2



                                                                                                Hanna Reef Oysters                                                                              Hanna Reer Oysters
                                                                                                Ship Channel Oysters                                                                            Ship Channel Oysters
                                                                                                                                     U


                                                 a     10     20     30     40      so     60     70      8 0     90    too                     0     10     20     30      40     so     60      70     so     90     100

                                                                              Tit me  (days)                                                                                 Time (days)


                                                                                                                  Fig. 18. (Continued)


                                                                                                                                                                                                                                              ON
                                                                                                                                                                                                                                              f-A














                                                      2,2',3,4,4',S' & 2,3,3',4,5,6       Hexachlorobiphenyis                                       2,20,3,4',S',6 Hetachlorobiphenyl ("AC No 149) &
                                                      (JUPAC No 138 & 160)                                                                          2',3,4,4',S Pentachlorobiphfnyl (IUPAC No 123)



                                                 100.                                                                                         100
                                                                                                                                         V


                                         c        10,                                                                                    C


                                                                                                                                         ILI

                                                                                                    IlannakeefOyst                                                                                  Ilanna Reef Oysters
                                                                                                                     er3
                                                                                                                                         0
                                                                                                    Ship Channel Oysters                                                                            Ship Channel Oysters
                                         U                                                                                               U

                                                    0      10     20     30      40     50     60     70     90      90     100                    0     10     20      30     40     50      60     70     so      90     100

                                                                                  Time   (days)                                                                                 Time (days)
                                                      2,2',4,4',5,5' & 2,2',3,3',4,6        Ilexachlorobiphenyis                                     2,2',3,4,4',5,6 Heptachloroblphenyl (JUPAC No 180)
                                                1000. (IUPAC No 153 & 132)                                                                     1000.



                                         L.      100,                                                                                           100,
                                                                                                                                         V

                                                                                                                                         cc


                                                 10                                                                                             10





                                                                                                    Ilanna ReefOyster3                                                                              Ilanna Red Oysters
                                                                                                    Ship Channel Oysters                                                                            Ship Channel Oysters
                                         U                                                                                               U
                                                 .I                                                IN P I @ - I i @ @ , -    .
                                                    0      10     20     30      40     50     60     70     so      90     100                    0      10     20      30     40     SO      60     70     so     to     M

                                                                                  Time (days)                                                                                    Time (days)


                                                                                                                     Fig. 18. (Continued)
                                                                                                                                                                                                    I     Red Oyst






                                                                                                                                                                                                    llarin.Reef@0








                                                                                                                                                            67









                                                                                                                 Ship Channel Oysters
                                                      2,2      "8'
                                                      2,
                                                        3::: (26)
                                                                                                                 Hanna Reef Oysters
                                                      2,4,4'   '2:1
                                                    2,2',3,4 (4
                                                   2,2',,3,5' (44)
                                                   2,2',4,1' (4
                                                              (5 9)
                                                   2,2',5,5' 2)
                                                    2,3',4'5 (70)
                                                    2,4,4',5 (74)
                                                 2,2',3,3',6 (84)
                                                 2,2',3,4,5' (87)
                                                 2,2',3,4',6 (91)
                                                 2,2',3,5,5' (92)
                                                 2,2',3,,S',6 (95)
                                                 2,2',3',4,5 (97)
                                                 2,2',4,4',5 (99)
                                               2,2',4,5,5'(101)        ..........
                                               2,3,3',4,4' (105)
                                               2,3,3',4',6 (110)
                                               2,3',4,4',5 (118)
                                             2,2',3,4,4',5' (138)
                                             2,2',3,4',5',6 (149)
                                             2,2',4,4',5,5' (153)    . ..... ....
                                          2.2',3,4,4',5,5' (180)

                                                                   0           20          40          60          80         100         120

                                                                                 Concentration (ng/g, dry wt.)


                                  Fig. 19. Concentrations of selected polychlorinated biphenyl congeners in tissues of
                                      Hanna Reef and Ship Channel oysters at the end of the 48-day exposure period.








                                                                                                                       68




                           period are presented. In general, the higher the number of chlorines substituted in the

                           biphenyl molecule, the larger the difference between the concentrations encountered in

                           HRSC and SC oysters. Typically, these differences, in percentages, ranged from -20%

                           to 20% for the lower molecular weight congeners, and from 40% to 60% for the higher

                           molecular weight PCBs (Fig. 20). A negative percentage indicates a higher concentration

                           in HR oysters compared to SC oysters, i.e. PCB congeners 28, 41, 44 and 91. The

                           predominant PCB congeners in HRSC individuals were l53(6)/l32(6Ml0(5)/77(4),

                           95(5),52(4), 101(5)/90(5), 118(5) and 70(4) compared to 153(6)/132(6), 110(5)/77(4),

                           101(5)/90(5), 95(5), 118(5), 52(4) and 138(6)/160(6) in SC oysters (the "/" indicates co-

                           eluting congeners; the numbers given in parentheses indicate the level of chlorination).

                           Combined, these congeners accounted for more than 40% of the total PCB load.

                              This study confirms previously published reports which indicate that the less

                           lipophilic congeners reach equilibrium concentrations, during both uptake and depurution,

                           at faster rates than the more lipophilic compounds  (Ellegehausen et al., 1980; Bruggeman

                           et al., 1981; Tanabe et al., 1987a), For example, there is an initial enrichment of the

                           lighter PCB fraction, e.g. congeners 95 and 52, in HRSC oysters. The concentrations of

                           these congeners, bowever, reached constant concentrations while the concentrations of the

                           more lipophilic congeners, e.g. 10 1 and 118, continued increasing. If the oysters were

                           allowed enough time, the final PCB distribution in HRSC oysters would probably have

                           approximated the distribution observed in SC oysters. Despite the differences observed in

                           equilibration rates of the various congeners, the composition of PCB homologs, in both

                           oyster populations, were largely dominated by penta-, tetra- and hexachloro-biphenyls

                           and had low concentrations of octa-, nona- and decachloro-biphenyls.

                              The dominant PCB congeners and homolog distribution encountered in newly and

                           chronically contaminated oysters at the end of the uptake period of this study are similar to

                           those reported for benthic invertebrates (Macoma balthica and Arenicola marina) and












                                                                                                                        difference



                                                                                            2,2',5 (18)
                                                               0
                                                                                            2,3',5 (26)
                                                                                            2,4,4' (28)
                                                                   PO                                    ................. .. . .............................. ..
                                                                        CL               2,2',3,4  (4l)-
                                                                                        2,2',3,5'  (44)-
                                                               rA  =    N
                                                                   CL
                                                                                        2,2',4,5'  (49)-
                                                                                        2,2',5,5'  (52)
                                                                                         2,3',4'5  (70)-
                                                                                         2,4,4',S  (74)-
                                                                                     2,2',3,3',6   (84)-
                                                                                                                          ............................. ...............


                                                                                     2,2',3,4,5'   (87)
                                                               En
                                                                                     2,2',3,4',6   (9l)-
                                                                        Un           2,2',3,5,5'   (92)-
                                                                        0
                                                                                     2,2,3,5 6     (95)
                                                                                     2,2',3',4,5   (97)
                                                                                     2,2',4,4',5   (99)-
                                                                                   2,2',4,5,5'   (101)  . . .... . .... .................. .... . ................ ....... - - - - - -------
                                                                                   2,3,3' 4,4'   (105)-
                                                                                   2,3,3':4',6   (110)-
                                                                                   2,3',4,4',5   (118)-
                                                                   0.a  0                               1
                                                                                 2,21,3,4,41,5,  (138)  . ............ ..... ..... ......R................................

                                                                        Cr
                                                                                 2,2',3,4',5',6  (149)
                                                                                 2,21,4,41,5,51  (153)
                                                                        Co
                                                                                                                         j...........
                                                                               2,2',3,4,4',5,5'  (180)]








                                                                                                                 70




                          sediments from the Dutch Wadden Sea where 10 1, 118, 138, 149, 153, 180 and 187, and

                          15, 18, 28, 118, 138, 153, and 187 were the dominant PCB congeners, respectively

                          (Duinker et al., 1983). Dominant PCB congeners in benthic polychaetes (Nephrys spp.)

                          from the southern North Sea were 118, 138, 149, 153 and 180, while in sediments the

                          highest concentrations corresponded to congeners 15, 18, 118, 138, and 153 (Boon et al.,

                          1985). Recently, Niimi & Oliver (1989) reported that the 10 most common congeners

                          detected in trout and salmon from Lake Ontario were 101, 84, 118, 110, 87/97, 153, 138,

                          149 and 180.

                             PCB congeners in Ship Channel sediments were dominated by pentachloro-biphenyls

                          and, to a lesser extent, by hexa- and tetrachloro-biphenyls (Fig. 21). Combined, these

                          three homologs represented more than 90% of the total sedimentary PCB load. Dominant

                          PCB congeners in sediments were 110(5)/77(4), 138(6)/160(6), 101(5)/90(5), 153(6)/

                          132(6) and 52(4). Each of these compounds accounted for more than 5% of the total

                          PCB load in the average sediment sample. This sedimentary PCB distribution is similar

                          to the distribution profiles encountered in HRSC and SC oysters.

                             Comparatively, PCB concentrations measured in water samples were significantly

                          lower (Fig. 21). The homolog PCB group with six chlorines represents the largest

                          portion of total PCBs in water, mainly because of the relatively high concentrations of

                          PCB 138 and 153.



                          Depuration   of PCBs by Newly and Chronically Contaminated Oysters

                             When relocated to the Hanna Reef area, Hanna Reef and Ship Channel oysters

                          showed statistically significant depuration of total PCBs. Tables A-8 and A-9 (Appendix)

                          list the average concentrations of predominant PCB congeners in HRSCHR and SCHR

                          oysters. Also listed are the average concentrations encountered in Hanna Reef sediments.
                          Total PCB concentration decreased from 830 to 380 ng g- I and from 1,100 to 730 ng g- I








                                                                                                                                             71







                                                     Ship Channel Sediments
                                                20-




                                                is




                                                10-










                                                        2        3        4       5        6                          9       10

                                                                              Level of Chlorination

                                                     Ship Channel Seawater
                                                3.0



                                                2.5



                                                2.0


                                        C
                                        ro-1    1.51
                                                1.0



                                                0.5,


                                                0.0
                                                        2        3       4        5        6        7        8        9       1*0

                                                                             Level of Chlorination


                                       Fig. 21. Concentrations of polychlorinated biphenyls, grouped by level of
                                                chlorination, in Ship Channel sediment and seawater samples.
                                                    I   .             ii,









                                                                                                                    72




                         in HRSCHR and SCHR oysters, respectively, after seven weeks at the Hanna Reef

                         location.

                             The concentrations of PCBs, grouped by level of chlorination, in both oyster

                         populations at different stages during the 50 days depuration period are shown in Fig. 22.

                         Different PCB congeners were depurated at different rates by SCHR and HRSCHR

                         oysters. Also, a marked decrease in the depuration efficiencies of the bioaccumulated

                         homologs with increasing number of substituted chlorines was observed in both groups

                         of oysters. For example, three-, four-, five- and six-chlorine substituted homologs

                         decreased 80, 70, 47, 20%, in HRSCHR oysters, and 73, 50, 24, 17%, in SCHR

                         individuals, respectively. This differential depuration of the accumulated PCBs can be

                         observed in Fig. 23 where the concentrations of selected PCB congeners in HRSCHR

                         and SCHR oysters at the end of the depuration period are shown. This retention of the

                         highly lipophilic congeners was more evident in chronically contaminated oysters.

                             Because of the incomplete depuration, the total PCB concentration in Hanna Reef

                         oysters, after 50 days, remained one order of magnitude higher than the original levels
                         (380 ng g- I versus 30 ng g- 1). The concentrations of homologs and selected PCB

                         congeners in Hanna Reef oysters before the transplantation to the polluted Ship Channel

                         site and 50 days after their relocation to the Hanna Reef area are shown in Fig. 24. The

                         distribution of PCBs in originally uncontaminated, i.e. HR, oysters shows a relafive

                         predominance of five- > four- > six-chlorine substituted homologs whereas the

                         predominant homologs in HRSCHR oysters were those having five, six and four

                         chlorines.

                             Depuration of PCBs by HRSCHR and HRSC oysters were approximately exponenfial

                         (Fig. 18). The clearance rates for high molecular weight PCBs were significantly slower

                         in both oyster populations. Transplanted HRSCHR oysters depurated most of the

                         recently incorporated PCB congeners at a faster rate than SCHR oysters. Detailed








                                                                                                                                                                                                       73






                                                      Hanna Reef Site - 0 day                                                             Hanna Reef Site - 19 days
                                               1000                                    0 Boom* Reer oysters                       1000,                                    M Hanna Reef Oysters
                                               9w                                                                                 900.
                                                                                       0 Ship Channel Oysters                                                              w Ship Channel Oysters
                                               11100                                                                              No.

                                          10   700                                                                          V     700-

                                               6w                                                                                 600

                                               so                                                                                 Soo

                                                                                                                                  400

                                               300                                                                                "o
                                          r
                                               200                                                                                200
                                          w                                                                                 w
                                                                                                                            C
                                               too                                         INTall                           U0    Joe
                                                   0                                                                                   0
                                                       1 2 3 4 5 6 7 9 9 10                                                               1 2 3 4 3 6 7 8 9 to

                                                                       Level of Chlorination                                                             Level of Chlorination
                                                     Hanna Reer Site - 3 days                                                     1000    Hanna Reef Site        30 days
                                                                                           Hanna Reef Oysters               1:1   900                                      ï¿½ Hanna Reeroysters
                                                                                           Ship Channel Oysters             i                                              E Ship Channel Oysters
                                                                                                                                  so
                                               700                                                                          V     700
                                               6oo                                                                          Gi    600
                                          at                                                                                at
                                               Soo                                                                                Soo
                                               400                                                                                400
                                               300                                                                                30
                                          C                                                                                       200
                                               200                                                                          w
                                               100                                                                          0     100
                                                                                     AIIIIIIIIIIII                -         U          0
                                                       1     2      3     4      5     6      7      9     9    10                        1     2     3       4    5       6    7      3     9     to
                                                                       Level or Chlorination                                                               Level  of Chlorination

                                                     Hanna Reef Site          6 days                                                      Hanna Reer Site        50 days
                                               1000                                    0 Hanna ReefOysters                        1000                                     0 Hamm ReerOysters
                                               900                                                                                900
                                                                                       0 Ship Channel Oysters               It                                             0 Ship Channel Oysters
                                          s.
                                               700                                                                                700

                                               60                                                                                 6"

                                               Soo                                                                                Soo.
                                          r
                                          0    400                                                                                400-
                                          at   300                                                                                300-

                                               200                                                                          ow    200-
                                          C                                                                                 C
                                          0    100                                                                          0                                    A-11
                                          U                                                                                 U     100
                                                   0                                                                                   0
                                                      1      2     3      4     3      6     7       8    9     10                        1     2     3       4    5       6    7     8      9     10

                                                                       Level of Chlorination                                                             Level of Chlorination


                                               Fig. 22. Concentrations of polychlorinated biphenyl congeners, grouped by level of
                                               chlorination, in back-transplanted Hanna Reef and transplanted Ship Channel oysters
                                                                     during the 50-day depuration period in the Hanna Reef area.
                                                                                                                                       LA
                                                                                                                                       I
                                                   L.i                                                                                 L                         4,









                                                                                                                                                            74










                                                                                                                 Ship Channel Oy      sters
                                                        2,2',5 (18)
                                                        2,3',5 (26)                                               Hanna Reef Oysters
                                                         2,4,4'(28)
                                                      2,2',3,4 (41)
                                                     2,2*,3,5' (44)
                                                     2,2',4,5' (49)
                                                     2,2',5,5' (52)
                                                     2,,3',4'5 (70)
                                                      2,4,4',S (74)
                                                   2,2',3,3',6 (94)
                                                   2,2',j3,4,5' (87)
                                                   2,2',3,4',6 (91)
                                                   2,2',3,5,5' (92)
                                                   2,2',3,,5',6 (95)
                                                   2,2',3',4,,S (97)
                                                   2,2',4,4',5 (")
                                                 2,2',4,5,5' (101)
                                                 2,3,3',4,4' (105)
                                                 2,3,3',4',6 (110)
                                                 2,3',4,4',5 (118)
                                              2,2',3,4,4',S' (138)
                                              2,2',3,4 5',6 (149)
                                              2,2',4,4',5,5' (153)
                                            2,2',3,4,4',S,S' (180)

                                                                     0          20          40          60         80          100         120

                                                                                  Concentration (ng/g, dry wt.)


                                  Fig. 23. Concentrations of selected polychlorinated biphenyl congeners in tissues of
                                      Hanna    Reef and Ship Channel oysters at the end of the 50-day depuration period.






                                                                                                                                                          75









                                                                                                               Before Transplantation
                                                      2,2',@5 (18)
                                                      2,3',5 (26)                                              After Depuration
                                                       2,4,4'(28)
                                                    2,2',3,4 (41)
                                                   2,2',3,5' (44)
                                                   2,2',4,5' (49)
                                                   2,2',5,5' (52)
                                                    2,3',4'5 (70)
                                                    2,4,4',5 (74)
                                                 2,2',"',6 (84
                                                 2,2',3,4,5' (87)
                                                 2,2',3,4',6 (91)
                                                 2,2',3,5,5' (92)
                                                 2,2',3,5',6
                                                              (95
                                                 2,2',3',4,5 (97)1
                                                 2,2',4,4',5 (99)
                                               2,2',4,5,5' (10 1)
                                               2,3,3',4,4* (105)
                                               2,3,3',4',6 (110)
                                               2,3',4,4',5 (119)
                                              2,2',3,4,4',5'(138)
                                             2,2',3,4',5',6 (149)
                                             2,2',4,4',5,5' (153)
                                                                                          RIM,,

                                          2,2',3,4,4',5,5' (180)



                                                                                 Concentration (ng/g, dry wt.)

                                    Fig. 24. Comparison of the concentrations of selected polychlorinai-ld biphenyl
                                   congeners measured in tissues of Hanna Reef oysters before exposure to the Ship
                                           Channel contaminant levels and after depuration at the Hanna Reef site.








                                                                                                                     76



                          discussion of the PCB biological half-lives and related kinetic parameters are presented in

                          Chapter VI. The estimated half-lives of selected PCB congeners in Hanna Reef and Ship

                          Channel oysters are listed in Table 4 for comparison purposes. Calculated PCB biological

                          half-lives ranged from 14 to 200 days in Hanna Reef oysters and from 18 to 595 days in

                          Ship Channel oysters. Similarly to previous studies, the biological half-lives of PCB

                          congeners increased with the number of chlorine atoms in the biphenyl rings. With the

                          exception of the values reported by Tanabe et al. (1987a), the estimated half-lives for

                          different PCB congeners during this study were comparable to most of the values

                          previously reported for a number of different organisms. In Tanabe's study, most of the

                          PCB congeners were depurated with extremely short half-lives, i.e. less than 10 days.

                              The average homolog concentrations in Hanna reef sediments (Fig. 25) were one

                          order of magnitude lower than the levels encountered in the Ship Channel area.

                          Comparing sediment samples from the Ship Channel area to the Hanna Reef location, it is

                          possible to observe some differences in the relative contribution of the different homologs

                          to the total sedimentary PCB load. While the average PCB distribution in Ship Channel

                          sediments is largely don-@dnated by pentachlorobiphenyls, sediment samples from the

                          Hanna Reef area show a slight predominance of hexachlorobiphenyls.



                          CONCLUDING REMARKS



                             Low molecular weight PCB congeners, i.e. those substituted with two, three and four

                          chlorines, were rapidly accumulated by transplanted oysters to final concentrations that

                          were not statistically differentiable from the concentrations encountered in indigenous

                          oysters. In most cases, these concentrations were reached in 30 days. Comparatively,

                          the bioaccumulation of higher molecular weight PCB congeners was much slower. As a

                          consequence of this slower uptake rate, the high molecular weight PCB congeners did not








                                                                                                                                             77






                                                                                TABLE 4
                              Biological Half-Lives (Days) of PCBs in Hama Reef and Ship Channel Crassostrea vir&ka Oysters.


                              Congener                                     Hanna Ship Pruell et al Tanabe et al Bruggeman et al.
                                                                            Reef    Channel     (1986)       (1987a)          (1981)
                                                                          oysters   oysters    mussels     mussels              fish


                              2.2',5 (18)                                    14        19                        6                14
                              2,3',5 (26)                                    22        22            -           -
                              2,4,4' (28)                                    17        34          16            7                 -
                              2,2',3,3' (40)                                 14        18            -           4                 -
                              2.2'.3,4  (41)                                 23        55            -           5                 -
                              2,2',3.5' (44)                                 27        45            -           6                 -
                              2,2',4,5' (49)                                 39        61            -           5                 -
                              2,2',5,5'   (52)                               27        45            -           6               46
                              2,3',4'.5   (70)                               30        58            -           6               69
                              2,4,4'.5  (74)                                 30        47            -           7                 -
                              2,2',3.3',6 (84)                               37        80            -           6
                              2,2',3,4.5'/2.3,4,4',6 (87/115)                55       132            -           5                 -
                              2,2',3,4',6 (91)                               25        50            -           5                 -
                              2,2',3,5,5' (92)                               31        63                        6                 -
                              2,2',3',5',6 (95)                              45        95                        5                 -
                              2.2',4,4',5 (99)                               49        91            -           6                 -
                              2,2',4,5,5'/2,2'.3,4',5 (101/90)               55       116          28            6                 -
                              2,3,3',4,4' (105)                              63       120            -           6                 -
                              2,3,3',4',5 (107)                              30        46            -           -                 -
                              2,3.3',4',6/3.3',4,4' (1 lOn7)                 45       103            -           6                 -
                              2,3',4,4',5 (118)                              73       299            -           7                 -
                              2,21,3,3,,4,4' (128)                           76       229          37            7                 -
                              2,2',3,4,4',5/2,3,3',4,5,6 (138/160)          200       595            -           8                 -
                              2.2'.3.4',5,5' (146)                          111       239                        -                 -
                              2,2',3,4',5',6/2',3,4,4'.5 (149/123)          130       439            -           7                 -
                              2,2',4,4',5,5/2,2',3,3',4,6' (153/132)         51       102          46            9                 -
                              2,2',3,3',4',5,6 (177)                         52       145            -          11                 -
                              2,2'.3.3'.5,5',6 (178)                         52        91            -           8
                              2.2',3,4.4',5.5' (180)                         50       142            -           7
                              2,2',3,4',5,5',6 (187)                         70       258            -          10








                                                                                                              78












                                       2.5                                     Hanna Reef Sediments


                                       2.0-



                                       US
                                C

                                I
                                C      1.0
                                Ix
                                       0-5         T
                                C


                                       0.0
                                             2      3      4                    7                   10

                                                              Level of Chlorination


                                 Fig. 25. Concentrations of polychlorinated biphenyls, grouped by level of
                                               chlorination, in Hanna Reef sediment samples.







                                                                                                                        79




                          attain equilibrium concentration by the end of the exposure period in this study and

                          statistically significant differences were evident between SC and HRSC oysters. In

                          general, the higher the number of chlorines substituted in the biphenyl molecule, the larger

                          the difference between the concentrations found in HRSC and SC oysters. In spite of

                          their lower uptake rates, pentachlorobiphenyls were the PCBs accumulated to the highest

                          concentrations in HRSC and SC oysters. In comparison, practically no congeners having

                          eight, nine or ten chlorines were accumulated by either oyster group. At the end of the

                          seven-week exposure period, the final distribution profiles of PCB homologs and

                          individual congeners in both transplanted (HRSC) and indigenous (SC) oysters were

                          similar to the profile encountered in sediment samples collected in the Ship Channel area.

                              When transplanted to the Hanna Reef location, both groups of oysters (i.e. HRSCHR

                          and SCHR) depurated the low molecular weight congeners at faster rates than the

                          clearance rates observed for the heavier PCBs. However, individual tetra- and

                          pentachlorobiphenyl congeners were depurated at a faster rate by HRSCHR than by

                          SCHR oysters. The concentration at the end of the 50-day depuration period measured in

                          FIRSCHR oysters was about one order of magnitude higher than the original level. In

                          both groups of oysters, the depuration efficiency decreased with the increasing number of

                          substituted chlorines in the biphenyl rings. This observed decrease in the clearance

                          efficiency is reflected in the estimated half-lives. In general, the less lipophilic congeners

                          reach equilibrium concentrations, during both uptake and depuration, at faster rates than

                          the most liphophilic PCB congeners.








                                                                                                                     80











                                                                CHAPTER IV




                                UPTAKE AND DEPURATION OF PLANAR PCB CONGENERS BY THE

                           AMERICAN OYSTER (CRASSOSTREA VIRGIMCA):A SPECIAL CASE OF PCBs



                          IN7MODUCnON



                             One of the objectives of this study was to evaluate the bioaccumulation of the highly

                          toxic planar PCB congeners, i.e. PCBs 77, 126 and 169, by bivalves under

                          environmental conditions. Most of the effort, however, was dedicated to the development

                          of a reliable technique for the isolation of non-ortho substituted tetra-, penta- and

                          hexachlorobiphenyl congeners that could be coupled to the existing cleanup procedures in

                          the laboratory.

                             This chapter serves two purposes. First, a new method for the isolation of the three

                          most toxic planar PCB congeners is presented and evaluated. As compared to previously

                          published methods for planar PCB analysis, this methodology saves both time and

                          materials, i.e. solvents, and eliminated the use of benzene, a highly carcinogenic solvent,

                          that requires extreme care in handling by the analyst. Second, the uptake and depuration

                          of these planar PCB congeners by transplanted oysters in Galveston Bay are determined

                          and discussed.








                                                                                                                  81





                        PLANAR PCBs: A REVEEW



                        Background Information

                            Of the 209 possible PCB congeners, only 20 have non-ortho chlorine substitutions in

                        the biphenyl rings. Some of these congeners can attain planarity, which makes them

                        sterically similar to the highly toxic dibenzo-p-dioxins and dibenzofurans (McKinney et

                        al., 1976, 1985; Hansen, 1987; McFarland & Clarke, 1989). Particularly important

                        within this group are the PCBs with no ortho, two para and at least two meta chlorines.

                        For example, congeners 3,3',4,4' tetrachlorobiphenyl (1UPAC No 77), 3,3',4,4',5

                        pentachlorobiphenyl (IUPAC No 126), and 3,3',4,4',5,5' hexachlorobiphenyl (1UPAC

                        No 169), shown in Fig. 26, are very potent mimics of the 2,3,7,8 tetrachlorodibenzo-p-

                        dioxin (TCDD) and 2,3,7,8 tetrachlorodibenzofuran (TCDF) both in P-450 induction and

                        toxic effects, e.g. body weight loss, dermal disorders, liver damage, thymic atrophy,

                        reproductive toxicity and immunotoxicity (Goldstein & Safe, 1989; Poland & Knutson,

                        1982; Safe, 1984, 1986, 1990; Tanabe, 1988). These planar PCBs are the most potent

                        pure 3-methylcholanthrene-type (3-MC-type) inducer congeners. Some studies have

                        indicated that not only non-ortho chlorine substituted PCBs but also some mono- and di-

                        ortho analogs of planar PCBs possess similar toxic potential (e.g. Robertson et al., 1984;

                        Safe, 1985; Bryan et al., 1987; Hansen, 1987; Olafsson et al., 1987; Tanabe et al.,

                        1987c; McFarland & Clarke, 1989).

                            In a recent review, Safe (1990) discussed the environmental and mechanistic

                        considerations behind the development of the Toxic Equivalent Factor (TEF) concept for

                        different PCBs. Safe proposed provisional TEF values of 0.01, 0.1 and 0.05 for planar

                        congeners 77, 126 and 169, respectively. Recently, the validation and limitations of these

                        factors have been reported (Safe, 1992).








                                                                                         82





                                                 PCBS
                        General Form 1a:               C12HIO-ncin
                          @@Cl                          en = Ito 10)

                        Nomenclature:


                            3   2   2'  3'
                          4Q-Q            4'

                        Planar Conaeners:


                          C1          C1       C1          C1       C1          C1
                        C"(D --- OC,         CIIL@@C'             cllc:@@C'
                                               C1                   C1          C1
                             PCB #77              PCB #126             PCB *169



                        Related _TD-x:i.Q Compounds:
                         Cla 0'-'OC1
                         C,      0        C1                     C       0        C1
                      2,3,7,&Tetrachlorodibenzo-p.dioxin        2,3,7,8-Tetrach1orodibefvofuran


                      Fig. 26. General formula of polychlorinated biphenyls. Three of the most toxic
                       planar PCB congeners, i.e. PCB 77, 126 and 169, are shown together with the
                                       compounds they mimic in toxic effects.







                                                                                                                   83




                            Although these planar PCB congeners represent a small portion of the total technical

                         PCB mixtures (Duinker & Hillebrand, 1983; Kannan et al., 1987; Schulz et al., 1989),

                         monitoring these compounds is needed because of their high toxicity. However,

                         quantitation of individual non-ortho substituted PCB congeners is very difficult because

                         of their extremely low concentrations.         Routine high-resolution capillary gas

                         chromatography analyses fails to separate some of these planar PCBs from other ortho-

                         PCB congeners, although this separation can now be achieved with more expensive and

                         complicated techniques such as multidimensional gas chromatography (Duinker et al.,

                         1988a).

                            During the last decade, a wide variety of different methodologies have been reported

                         for the separation of individual PCBs, according to the number of chlorines in the ortho

                         positions, using different adsorbents, such as. florisil and activated carbon. In general,

                         the existing methods for the separation of planar PCBs from other congeners use an

                         extremely large volume of eluant per sample, i.e. over 1000 ml (e.g. Huckins et al., 1980;

                         Stalling et al., 1980), involve a carcinogenic solvent, i.e. benzene, (e.g. Tanabe et al.,

                         1987; Hong & Bush, 1990;"Kuehl et al., 1991, or are extremely complicated for routine

                         analysis (e.g. Smith et al., 1984, Patterson Jr. et al., 1989).



                         Distribution and Occurrence in Galveston Bay

                            Although PCB congeners have been widely reported in Galveston Bay samples (Table

                         3) and have been one of the most commonly found chlorinated compounds in oyster

                         samples from Galveston Bay (Sericano et al, 1990a), the occurrence of planar PCB

                         congeners in this area have not, until recently, been reported (Sericano et al., 1992).

                            This study, which is discussed in greater details in Chapter VIII, reports the

                         occurrence of three highly toxic PCB congeners (PCBs 77, 126 and 169) in oysters

                         (Crassostrea virginica) fi-om different locations in Galveston Bay using a newly developed








                                                                                                                  84



                         carbon chromatographic method (Sericano et al., 1991). The highest concentrations of

                         planar PCB congeners in Galveston Bay were reported in samples collected near the area

                         where the Houston Ship Channel enters the upper Galveston Bay (2,000, 2,200 and 790
                         pg 9_1 for congeners 77, 126 and 169, respectively) and decreased seaward. The second

                         highest concentrations were encountered in samples from near the city of Galveston (500,
                         400 and 93 pg g- I for congeners 77, 126 and 169, respectively). The lowest

                         concentrations were measured in samples collected near Hanna Reef in East Bay (89, 110
                         and 89 pg g-I for congeners 77, 126 and 169, respectively). The general distribution of

                         planar PCB congeners in Galveston Bay clearly correlates high concentrations with highly

                         populated areas. The same correlation between urban centers and concentrations was

                         observed in Tampa Bay (Sericano er al., 1992).



                         Bivalve Uptake and Depuration Studies

                            The number of studies reporting the uptake and depuration of PCBs by different

                         bivalves is limited. Even more limited is the number of studies reporting the uptake,

                         persistency and release of highly toxic planar PCB congeners. In one of the first reports

                         regarding the bioconcentration of planar PCB congeners in lower aquatic organisms, e.g.

                         Green-lipped mussels (Perna viridis Linnaeus) and possible transfer through food chain to

                         higher animals, it was concluded that these compounds are highly bioaccumulated by

                         lower organisms and, because of their persistence, they may reach higher consumers,

                         including humans, in quantities of toxicological concern (Kannan et al., 1989).







                                                                                                                     85





                          UPTAKE AND DEPURATION OF PLANAR PCBs



                          Experimental Design, Sample Collection and Methods

                              The experimental design and sample collection used for the study of planar PCBs

                          were the same as those discussed for PAHs (Chapter 11).



                          Extraction and initial sarVIefractionation

                              The extraction, initial fractionation and cleanup of planar PCBs were done

                          simultaneously with the rest of the ortho-substituted PCBs. After the final extract

                          concentration to I ml, and before the addition of the GC internal standard for GC-ECD

                          analysis, a 250 gl fraction was reserved for the analysis of planar PCB congeners.

                          Before proceeding to the next step, PCB 81 was added to the extracts as an internal

                          standard.



                          Isolation ofplanar PCB congeners

                             The methodology to analyze planar PCBs in transplanted oyster tissues is published

                          elsewhere (Sericano et al., 1991). Glass chromatographic columns (10 mm i.d.) were

                          packed in methylene chloride. Two g of the adsorbent, a 1:20 mixture of activated AX-21

                          charcoal (Super-A activated carbon) and LPS-2 silica gel (Low-pressure silica gel, particle
                          size 37-53 gm, 450 m2g-1), were packed between two layers of anhydrous sodium

                          sulfate. The adsorbent mixture was carefully checked for interfering compounds by

                          running blanks with the solvent mixtures used to elute the column. Oyster tissue extracts

                          were sequentially eluted from the column     with 50 ml of 1:4 methylene chloride and

                          cyclohexane, 30 ml of 9:1 methylene chloride and toluene, and 40 ml of toluene. The
                          flow rate through the column was 1.5 to 2.0 ml min- 1. The first two solvent mixtures

                          were collected as one fraction (f 1) and contained the bulk of PCB congeners. The second








                                                                                                                     86




                         fraction 02), containing the ortho unsubstituted PCB congeners with four, five and six

                         chlorines in meta and para positions, was concentrated to a final volume of 0. 1 ml, in

                         hexane, for GC-ECD analysis.



                         Instrumental analysis

                             Planar PCB congeners were analyzed by fused-silica capillary column GC-ECD
                         (Ni63) using a Hewlett Packard 5880A GC in splitless mode. Capillary columns, 30 m

                         long x 0.25 mm i.d. with 0.25 gm DB-5 film thickness, were tempera ture-programmed
                         from 100to 150OCatlOOC min-l and from 150to270OCat6'Cmin-I with I min hold

                         time at the beginning of the program and before the program rate change. A hold time of

                         3 min was used at the final temperature. Total run time was 30 min. Injector and detector

                         temperatures were set at 275 and 325'C, respectively. Helium was used as the carrier gas
                         at a flow velocity of 30.0 cm sec-1 at 100'C. Nitrogen or argon/ methane (95:5) were
                         used as the make-up gas at a flow rate of 20 ml min-1. The volume injected was 2 gl.

                         Planar PCBs were quantitated against a set of authentic standards that were injected at four

                         different known concentrations to calibrate the instrument and to compensate for a non-

                         linear response of the electron capture detector. Tetrachloro-m-xylene (TCMX) was used

                         as the GC internal standard to estimate the recoveries of the internal standards. The

                         detection limits for organochlorines and individual PCB congeners, calculated on the basis

                         of 15 g (wet weight) oyster tissue sample size with 0.2% by volume of the extract injected
                         into the GC-ECD, was 0.05 ng g- I dry weight.



                         Planar PCB Congener Analysis

                            Activated carbon has been previously used to separate chlorinated compounds based

                         on the degree of chlorination as well as molecular planarity (e.g. Jensen & Sundstr6m,

                         1974; Stalling er al., 1980). In the case of PCBs, for example, the planar structure is








                                                                                                                         87




                           related to the number of chlorines in the ortho positions. Based on the high surface area

                           of activated carbon and its selective adsorptive capacity of planar structures, this adsorbent

                           can be successfully used to isolate planar PCB congeners having four or more chlorines in

                           meta and para positions. Although PCB congeners with a decreasing number of ortho

                           substituted chlorines were differentially retained in the column (Stalling et al., 1980), all

                           the PCBs with at least one ortho chlorine were eluted by the first two solvent mixtures and

                           collected in one fraction. Thd mixture of I part of AX-21 activated carbon and 20 parts of

                           LPS-2 silica gel was relatively easy to pack and use.

                              The efficiency of the column was initially checked with a mixture of PCBs, Aroclor
                           1254 (5,000 ng ml-1), spiked with the four planar PCB congeners. These analytes were

                           added in triplicate to the Aroclor mixture at three different concentrations (20, 50 and 100
                           ng m.1-1). Fig. 27 shows the chrornatograms of spiked Aroclor 1254 (a), PCB congeners

                           recovered in the first fraction, i.e. 50 ml of 1:4 methylene chloride and cyclohexane

                           followed by 30 ml of 9:1 methylene chloride and toluene (b), and planar PCBs eluted in

                           the second fraction, i.e. 40 ml of toluene (c). Recoveries of planar PCB congeners are

                           reported in Table 5. Recoveries for the three highly toxic planar PCB congeners were

                           above 90%, whereas that for PCB 81 was slightly lower. Recoveries in the first fraction

                           of PCB congeners having one to four chlorines in the ortho-ortho' positions were, in all

                           cases, near 100%.

                              To investigate the efficiency of the column with environmental samples with high lipid

                           concentrations, dolphin blubber extracts were spiked with the same four planar PCB
                           congeners at a concentration of 50 ng g- I each. Total PCB concentration in the dolphin
                           blubber was 3,700 ng g-l. Fig. 28 shows the chromatograms of the spiked dolphin

                           blubber sample (a).as well as the ortho- and non-orthochlorine substituted PCB congeners

                           recovered in the first and second fractions, b and c respectively. Also, these planar PCB

                           congeners were isolated from other organochlorine compounds present in the blubber








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                                                                                                                         90




                           extract, i.e. chlordane-related compounds and DDT and its metabolites DDD and DDE.

                           Spiked dolphin blubber samples also had excellent recoveries for these PCB congeners,

                           comparable to those calculated for the spiked Aroclor mixture (Table 5). Recoveries for

                           all the chlorinated hydrocarbons originally present in the dolphin blubber sample were

                           close to 100%. Only a negligible concentration of p-p'DDE, detected in the original
                           sample at a very high concentration (1,450 ng g-1) was present in the final fraction (Fig.

                           28c).

                               Overall, this method yielded higher or similar recoveries for PCB congeners 77, 126

                           and 169 than those reported by Kamops et al. (1979), Huckins et al. (1980), Smith et al.

                           (1984), Tanabe et al. (1987) and Hong & Bush (1990) at comparable concentrations

                           using either florisil or carbon chromatography on pure standard solutions or spiked

                           samples.



                           Uptake of Planar PCBs by Transplanted Oysters

                               Ship Channel, Hanna Reef, transplanted Hanna Reef-to-Ship Channel, transplanted

                           Ship Channel- to-Han na Reef and relocated Hanna Reef-to-Ship Channel-back to-Hanna

                           Reef oysters are refered as SC, HR, HRSC, SCHR and HRSCHR oysters, respectively,

                           in this and the following sections.

                               Concentrations of planar congeners in transplanted HRSC oysters were encountered at
                           very low concentrations, e.g. parts per trillion (pg g- 1) to parts per billion (ng g- 1). The

                           lowest concentrations corresponded to congener 3,3',4,4',5,5' (169), which was present

                           at concentrations near or below the detection limits. Fig. 29 illustrates both the

                           applicability of this technique to real environmentally contaminated samples and the
                           difficulties involved in the analysis of planar PCB's because of their extremely low

                           concentrations. The chromatograms correspond to an extract of indigenous SC oysters.

                           Fig. 29a shows the ortho substituted PCBs eluted in the first fraction with the two








                                                                                                                           91










                                                                       TABLES
                               Recoveries of Four Planar PCB Congeners from Spiked Aroclor 1254 and Dolphin
                                             Blubber Samples Using Activated Carbon:Silica Columns.


                               PCB congeners                      Aroclor 1254                      Blubber      Average
                                                      Level I      Level H       Level HI
                                                    20 ng ml- I    50ngml-l lOOngml-I              50 ng g-I


                               3,4,4',5 (81)           85ï¿½1.8         82ï¿½8.6         79ï¿½4.0         82ï¿½5.4          70ï¿½2.3
                               3,3',4,4'(77)          100ï¿½4.8         94ï¿½9.0         90ï¿½4.1         94ï¿½7.2          87ï¿½4.0
                               3,3',4,4',5 (126)       90.ï¿½0.6        96ï¿½5.5         94+' 2. 1      93ï¿½3.9          91ï¿½2.8
                               3,3',4,4',5,5'(169)     94ï¿½1.0         96ï¿½3.4         97ï¿½1.1         96ï¿½2.5          97ï¿½2.3








                                                                                                             92


















































                                                                    Cot-
                                                                     t-





                         Fig. 29. Example  of high-resolution gas chromatograms obtained from an extract of
                             indigenous Ship Channel oysters. PCB congeners are numbered according to
                                                     ]Ballschn-@tter & Zell, 1980.








                                                                                                                  93




                        different solvent mixtures. Fig. 29b shows, for comparison, the planar congener

                        fraction, i.e. second fraction, at the same magnification as the chromatogram

                        corresponding to the first fraction and Fig. 29c shows the second fraction magnified 20

                        times.

                            Both, 3,3',4,4' tetraCB (77) and 3,3',4,4',5 pentaCB (126) exhibit fairly well-

                        defined uptake and depuration curves. Fig. 30 shows the concentrations of PCB

                        congeners 77 and 126 versus time during the uptake and depuration pe          riods. The

                        concentrations of these two planar PCB congeners in HRSC oysters increased over the

                        seven week exposure period. PCB congener 77 reached a concentration similar to that

                        encountered in indigenous SC oysters within a month. The uptake of congener 126 was

                        slower and only approximated the concentration of SC oysters by the end of the exposure

                        period. Contrasting with planar PCBs 77 and 126, it was not possible to observe a clear

                        trend in the concentration of congener 169 versus time. This is mainly because of its

                        extremely low concentration.

                            The final concentrations of the accumulated congeners decreased as the number of

                        chlorines substituted in the biphenyl rings increased. This trend was also reported in

                        transplanted green-lipped mussels (Perna viridis Linnaeus) during an exposure experiment

                        in Hong-Kong waters (Kannan et al., 1989). Kannan et al. (1987) reported the

                        concentrations of these planar congeners in different commercial PCB mixtures. In

                        general, congener 77 is 1-2 and 3-5 orders of magnitude higher than congeners 126 and

                        169, respectively. Comparing these relative concentrations with those observed in

                        transplanted oyster samples, it appears that congeners 126 and 169 in oyster tissues were

                        enriched with respect to congener 77. The same observation was made by Kannan et al.
                        (1989). This is not. surprising since the log Kow (octanol-to-water coefficient) increases

                        with the number of chlorines substituted in the biphenyl rings (6.36, 6.89 and 7.42 for
                        congeners 77, 126 and 169, respectively; Hawker & Connell, 1988). In general,








                                                                                                                   94







                                              3,3'4,4' Tetrachlorobiphenyl  (IUPAC No 77)
                                      20000-.                                        Hanna Reef Oysters
                                                                                     Ship Channel Oysters






                                       3LOOO



                                   41






                                        100                            .. .............
                                             0    10    20    30    40    50    60     70    go     90  100

                                                                     Time (days)


                                              3,3',4,4',5 Pentachlorobiphenvi (IUPAC No 126)
                                        1000-.
                                                                                     Hanna Reef Oysters
                                                                                     Ship Channel Oysters


                                   qz




                                         loo-,









                                          10
                                             0    10    20    30    40    so    60    70     so     90  100

                                                                     Time (days)

                           Fig. 30. Concentrations of planar polychlorinated biphenyl congeners 77 and 126 in
                                tissues of Hanna Reef oysters during the uptake and depuration phases of the
                                               transplantation experiments at Galveston Bay,







                                                                                                                   95




                         concentrations for congener 77 in oyster tissue were 3-5 and 10-12 times higher than

                         those measured for congeners 126 and 169, respectively.



                         Depuration of Planar PCBs by Newly Contaminated Oysters

                            When transplanted to the Hanna Reef area, exposed oysters slowly depurated the

                         concentrated planar congeners. These PCBs were still present at high concentrations,

                         relative to original HR oysters, by the end of the 50-days depuration period. Kannan et

                         al. (1989) also observed that the concentrations of these planar PCB congeners in

                         transplanted green-lipped mussels (Perna viridis Linnaeus), at the end of the exposure

                         period (32 days), were substantially higher than those found in native individuals.

                            Depuration of congener 77 was comparatively faster than the clearance rate observed

                         for congener 126. Calculation of half-lives and related kinetic parameters of these trace

                         organic pollutants will be discussed in greater details in Chapter VI. For comparison

                         purposes, the estimated biological half-lives of these toxic PCBs were 88 and 107 days

                         for congeners 77 and 126, respectively. These estimated values were significantly higher

                         than those reported by Kannan et al. (1989) for mussels (9 and 13 days, respectively).

                         However, it must be noted that, as previously discussed in Chapter III, all the biological

                         half-lives reported for different PCB congeners in that transplantation study (i.e. Tanabe

                         et al., 1987a; Kannan et al., 1989) were significantly lower than the estimated half-lives

                         during this study and previous reports involving bivalves as well as many other

                         organisms (Table 4). The estimated biological half-lives for tetra- and pentachloro

                         substituted PCB congeners during this study were in the 14 to 39 and 25 to 73 days

                         ranges, respectively (Chapter VI, Table VII). It is clear that, compared to other ortho-

                         substituted congeners with the same number of chlorine per molucule, planar PCBs are

                         removed more slowly from the lipid pool of oysters. The same observation was reported







                                                                                                                      96




                           for transplanted green-lipped mussels (Perna viridis Linnaeus) in Hong-Kong (Kannan er

                           aL, 1989).



                           CONCLUDING REMARKS



                               A simple, sensitive, precise and specific method for the isolation of planar PCB

                           congeners, with four or more chlorines in non-ortho positions, from other PCBs in

                           environmental samples was developed for this study. This method, which can easily be

                           coupled to existing cleanup procedures in most environmental laboratories currently

                           involved in the high-resolution gas chromatographic analysis of PCBs, yields acceptable

                           recoveries of these PCB congeners. Compared to other methods, this methodology saves

                           both time and materials, i.e. solvents, and is safer for the analyst and the environment.

                               Two of the most toxic planar PCB congeners, i.e. congeners 77 and 126, were

                           biococentrated by transplanted oysters during the seven-week exposure period. Congener

                           77 attained an equilibrium concentration with the indigenous oysters in a shorter period of

                           time than congener 126. Because of the low concentrations, it was not possible to

                           observe a clear trend in the uptake of PCB congener 169.

                               When newly contaminated oysters were transplanted back to the Hanna Reef area,

                           they depurated both 77 and 126 planar PCB congeners; however, the estimated depuration

                           half-lives were significantly longer than those corTesponding to non-planar PCBs with the
                                         I
                           same number of chlorines substituted in the biphenyl molecule. Also, the final

                           concentrations of these planar PCB congeners in HRSCHR oysters at the end of the

                           depuration phase of this experiment remained relatively high. Because of their toxicity

                           and per sistency, these planar PCB congeners are of importance in environmental studies.

                           These congeners are bioconcentrated and retained by bivalves and constitute a potential

                           health hazard for higher consumers, including human beings.








                                                                                                                       97

                                                                                                                                  01-











                                                                  CHAPTER V




                             UPTAKE AND DEPURATION OF TRIBUTYLTIN BY THE AMERICAN OYSTER

                                                        (CRASSOSTREA VIRGINICA



                           INMODUCTION



                               Tributyltin is the active component in antifouling paints. However, this compound

                           has been shown to be highly toxic to a wide variety of aquatic organisms rather than being

                           specific to the target individuals. This observation has generated a growing interest in the

                           bioaccumulation of TBT by marine organisms. In this chapter, the bioconcentration of

                           TBT and its depuration by transplanted and chronically contaminated oysters are

                           discussed.




                           TBT: A REVEEW



                           Background Information

                               Evans & Karpel (1985) defined organotin compounds as compounds in which at least

                           one direct tin-carbon bond exists. Most of the organotin compounds have fin in the IV+

                           oxidation state giving four series of organotin compounds: mono-, di-, tri- and

                           tetraorg anotins.    Properties of these organotin classes are different.             While

                           monoorganotins have low toxicity, for example, the triorganotin compounds have biocidal
                           properties. Diorganotins are used as stabilizers in the plastic industry.







                                                                                                                       98




                              These organotin compounds, which were introduced commercially in U.S.A. in the

                          1940s (Evans & Karpel, 1985), found use as stabilizers of polyvinylchloride (PVC),

                          industrial catalyzer in the synthesis of polyurethane foams, epoxy resins, plastic materials,

                          wood preservative and biocide. Within the scope of the last application, butyltins are the

                          organotin compounds most widely used. Butyltins, in the form of tributyltin (TBT)-

                          based paints, are highly effective as antifouling agents. With a useful life between 5 and 7

                          years (Champ & Pugh, 1987) and an effectiveness 10 to 100 times greater than copper-

                          based paints (Anderson & Dalley, 1986; Ludgate, 1987), the use of paints containing

                          TBT presents important economic benefits. For example, it has been reported that a six-

                          month accumulation of fouling organisms, e.g. barnacles, seaweeds and tubeworms, on

                          ship bottoms increases up to 40% the non-nal fuel consumption (Hall & Pinkney, 1985).

                          Associated with the economical benefits, there were environmental risks. Because of the

                          slow mode of action of TBT, standard, short duration tests failed to indicated its toxicity

                          (Laughlin & Linden, 1987).

                             Contamination of the coastal marine environment by tributyltin has been investigated

                          since the early 1980s when French workers discovered that TBT caused malformations

                          and reduced growth in the Pacific oyster, Crassostrea gigas (Alzieu et al., 1980, 1982).

                          Similar effects have been reported in England (Anonymous, 1980; Abel et al., 1986) and

                          the United States of America (Stephenson et al., 1986; Salazar et al.. 1987, Salazar and

                          Salazar, 1987, 1988; Valkirs et al., 1987a). As a result, the use of antifouling paints

                          containing TBT on vessels under 25 m has been banned in France (1982), England

                          (1987), and the United States of America (1988) (Anonymous, 1980; Knipe, 1989; U.S.

                          Environmental Protection Agency, 1987). The increased concern about the adverse

                          effects of TBT to non-target organisms led to the decision in the U.S. to include the

                          analysis of butyltin compounds as part of the National Oceanic and Atmospheric








                                                                                                                      99



                           Administration's National Status and Trends "Mussel Watch" (NOAA's NS&T) Program

                           (e.g. Wade et al., 1988a).



                           Distribution and Occurrence in Galveston Bay

                               Because TBT was not considered to be an environmental threat until the late 1980s,

                           studies directed at understanding the occurrence and fate of this contaminant in Galveston

                           Bay are recent and very limited (Table 6). Wade et al. (1988) reported the results of a

                           study designed to understand its temporal and spatial variations in bivalves collected from

                           four sites in Galveston Bay. This study indicated that the TBT concentrations were higher

                           in samples from sites located closer to known sources of inputs, i.e. the Galveston Bay

                           Yacht Club. A decrease in TBT concentrations is reported toward the outer part of the

                           Bay. Similarly, the highest TBT concentrations in Galveston Bay sediment samples were

                           reported near the Galveston Bay Yacht Club (Wade et al., 1990).



                           Bivalve Uptake and Depuration Studies

                               Compared to PAHs and PCBs, the number of studies of uptake and depuration of

                           TBT by bivalves is limited. Although contamination of the coastal environment by TBT,

                           for example, has been investigated since early 1980s, it was not until the late 1980s that

                           this compound was considered to be a real threat to the quality of coastal waters.

                               Controlled flow-through experiments have shown that mussels accumulate increasing
                           amounts of TJ3T over a 60 day period, reaching a steady state concentration thereafter

                           (Salaza er al., 1987). Reported half-life for TBT in field studies with diffesent bivalves

                           were relatively short (Mytilus edulis, 14 days, Laughlin et al., 1986; Crassostrea gigas

                           and Ostrea edulis, 10 days, Waldock et al., 1983). Depuration rate constants calculated

                           from laboratory data were found to be much lower than those obtained in environmental

                           studies (Laughlin et al., 1986). For example, the longer half-life (40 days) recently















                                                                                           TABLE6
                           TBT, DDT and MBT Concentrations (in ng Sn g-        on a Dry-Weight Basis) in Oyster and Sediment Samples from the Galveston Bay Area.


                          Location                      Sample                     TBT            DBT            MBT         Total OTs              Reference


                          Yacht Club                    oysters                    660             70              10            740                Wade et al., 198 8a
                          Todd's Dump                   oysters                    380             30              10            420                Wade el al., 1988a
                          Confederate Reef              oysters                    380             30              10            420                Wade el al., 1988a
                          Hanna Reef                    oysters                    110             10              <5            120                Wade et al., 1988a


                          Yacht Club                    sediments                    13            <5              <5              13               Wade et al., 1990
                          Todd's Dump                   sediment%                     7            <5              <5               7               Wade et al., 1990
                          Confederate Reef              sediments                     6            <5              <5               6               Wade et al., 1990
                          Hanna Reef                    sediments                    11            <5              <5              11               Wade et al., 1990







                                                                                                                  101




                         reported for mussels (Mytilus edulis) in laboratory depuration studies (Zuolian & Jensen,
                         1989) might reflect the effects of bivalve manipulation.



                         UPTAKE AND DEPURATION OF TBT



                         Experimental Design, Sample Collection and Methods

                             The experimental design and sample collection used for the study of TBT were the

                         same as those discussed for PAHs (Chapter 11).



                         Exraction and sarVIefractionation

                             The analytical procedure used during this study is a modification of previously

                         reported methods (Maguire, 1984; Unger et al., 1986; Matthias et al., 1986) and is

                         discussed in detail elsewhere (Wade et al., 1988a). Approximately 15 g (wet weight) of

                         tissue sample was weighed into a 250 ml centrifuge tube. Anhydrous sodium sulfate (40

                         g), 0.2% tropolone in methylene chloride (100 ml) and tripropyltin chloride as an internal

                         standard were added. The sample was extracted for 3 min with a Tekmar Tissuemizer,

                         centrifuged, and the supernatant was decanted into a 500 ml flat-bottom flask. The

                         extraction was repeated two more times with 0.2% tropolone in methylene chloride (100

                         ml). The combined extracts were concentrated in a water bath (600C) and the methylene

                         chloride was replaced by hexane. The sample was then purged with nitrogen and hexyl-
                         magnesium bromide (2 ml, 2 M Grignard reagent) was added. The hexylation reaction

                         was carried out for 6 h at 50'C. HCl (5 ml, 6 M) was then added to neutralize the excess

                         Grignard reagent. The sample was shaken        vigorously and the organic and aqueous

                         phases were allow  to separate. Two more extractions were perforned using a mixture of

                         pentane:methylene chloride (2:1, 125 ml). The organic phase was dried with anhydrous

                         sodium sulfate and concentrated to 2 ml in hexane. The hexylated organotin compounds








                                                                                                                102




                          were isolated on a column containing combusted alumina (4000C, 17 g) and silica (170'C,

                          13.5 g). The column was eluted with pentane (60 n-d). The sample was then concentrated

                          to 500 gl. Samples were spiked with tetrapropyltin before analysis to determine recovery

                          of the internal standard for the whole analytical procedure.



                          Instrwnental analysis

                             Butyltin species were analyzed by gas chromatography on a Hewlett-Packard 5790

                          gas chromatograph (GQ equipped with a capillary column (DB-5, 30 m x 0.25 mm i.d. x

                          0.25 pm coating thickness) and a flame photometric detector (FPD). The GC temperature

                          was programmed from 60'C to a final temperature of 300'C, at a rate of 12*Qmin, with a

                          final 10 min hold time. Injector and detector temperatures were 300 and 250'C,

                          respectively. Helium was used as the carrier gas. The response of the FPD was selective

                          for Sn using a 610 nm filter. The limit of detection of TBT and breakdown products,
                          dibutyltin (DBT) and monobutyltin (MBT), was 5 ng Sn g- I dry weight.



                          Ancillary pararwrers

                             Methodologies for the sediment grain-size analysis and extractable lipids percentage

                          were discussed in the materials and methods section of Chapter 11.



                          Statistical analysis

                             The statistical analyses performed on the TBT data were previously discussed in the

                          materials and methods section of Chapter 11.



                          Uptake  of TBT by Transplanted Oysters

                             In this and the following sections, Ship Channel, Hanna Reef, transplanted Hanna

                          Reef-to-Ship Channel, transplanted Ship Channel-to-Hanna Reef and relocated Hanna







                                                                                                                  103




                         Reef-to-Ship Channel-back to-Hanna Reef oysters are refered as SC, HR, HRSC, SCHR

                         and HRSCHR oysters, respectively.

                            Average concentrations of TBT encountered in oyster and sediment samples, are

                         reported in Table A-10 (Appendix). TBT concentrations in SC oysters during the uptake
                         phase of this experiment were very stable (mean= 340ï¿½39 ng Sn g-1, relative standard
                         deviation = I I%, range = 330-420 ng Sn g- 1) suggesting that bioavailable TBT to the

                         oysters was,relatively constant. Therefore, it is assumed that the accumulation rate in

                         HRSC transplanted oyster was not affected by changes in the concentration of

                         bioavailable TBT.

                            Approximately a 10-fold increase in TBT concentrations was observed by the end of

                         the exposure period in HRSC oysters (Fig. 31). By the end of the seven-week exposure

                         period, the concentration of TBT in HRSC oysters was similar to the level found in SC

                         oysters. This increase is similar to previously reported uptake data in exposed mussels
                         after about 50 days (Laughlin, Jr., et al., 1986; Zuolian & Jensen, 1989). Controlled

                         flow-through experiments have shown that mussels reach a steady state concentration of

                         TBT after a 60-day exposure period (Salazar et al., 1987). A steady state concentration

                         was not attained in this study; however, the continued increasing concentrations of TBT

                         measured in transplanted oysters by the end on the seven-week uptake period seem to

                         indicate that, given enough time, a true equilibrium concentration comparable to the levels

                         measured in native oysters would have been reached.
                            DBT, the major breakdown product of TBT (Maguire, 1984; Seligman el al., 1986),

                         did not show any accumulation during the exposure period and was only detected at low

                         concentrations in both groups of oysters. This might suggest that DBT, a more polar and

                         soluble 'compound   than TBT, may be quickly depurated from the oyster tissues. DBT
                         concentrations ranged from 22 to 34 ng Sn g-l and <5 to 22 ng Sn g-I in SC and HRSC







                                                                                                                 104







                                    1000  Tributyltin


                               42

                                C


                                     100.






                                                                                    Hanna Reef Oysters
                                                                                    Ship Channel Oysters
                                      10                                                  ............  I
                                        a     10     20    30    40     so    60    7 0    80    90    100
                                                                  Time (Days)


                              Fig. 31. Concentrations of tributyltin in tissues of Hanna Reef and Ship Channel
                              Oysters during exposure to the Ship Channel area contaminant levels and following
                                                      transplant to the Hanna Reef are.







                                                                                                                    105



                         oysters, respectively, whi.le MBT concentrations were, in all cases, below the 5 ng Sn g-I

                         Umit of detection.

                             Sediment samples collected from the Ship Channel and Hanna Reef locations during

                         this study had TBT, DBT, and MBT concentrations below the detection limits.



                         Depuration of TBT by Newly and Chronically Contaminated Oysters

                             Both oyster populations showed statistically significant depuration of TBT after back-

                         transplantation to the Hanna Reef area. The final TBT concentration encountered in

                         HRSCHR individuals at the end of the 50- day depuration period was over 100% higher

                         than the levels measured in the same group of oysters before the transplantation

                         experiment to the Ship Channel area.

                             The calculated half-life for TBT in the originally uncontaminated Hanna Reef oysters

                         (21 days) was higher than the values reported for mussels (Mytilus edulis, 14 days,

                         Laughlin et al., 1986) and the Pacific (Crassostrea gigas) and European (Ostrea edulis)

                         oysters (10 days, Waldock er al., 1983). Depuration rate constants calculated from

                         laboratory data were found to be much lower compared to environmental studies

                         (Laughlin et al., 1986). For example, the longer half-life (40 days) recently reported for

                         mussels (Mytilus edulis) in laboratory depuration studies (Zuolian & Jensen, 1989) might

                         reflect the effects of bivalve manipulation. Comparatively, the TBT half-life in chronically

                         exposed oysters, i.e. SCHR oyster, was 27 days.

                             As discussed in previous chapters, similar differences in the depuration rates, i.e.

                         half-lives, were observed for other trace or-anic contaminants between newly and

                         chronically contaminated oysters. In the specific case of TBT, a possible explanation of

                         these different depuration rates could be the existence of ligands within the oyster body as

                         suggested by Laughlin (1990). These ligands, which do not seem to be induced by TBT

                         exposure, might be produced slowly by chronically exposed bivalves. Tissue molecules








                                                                                                                   106




                          with groups containing sulfur, oxygen or nitrogen are mentioned as the obvious ligand

                          candidates. Ilerefore, the existence of these ligands in one group of oysters, but not in

                          the other, might explain the difference observed in depuration rates.



                          CONCLUDING REMARKS



                             Although a steady state concentration was not reached, transplanted oysters rapidly

                          accumulated TBT to practically reach an equilibrium with the concentrations encountered

                          in indigenous oysters at the end of the 48-day exposure period. DBT, a more polar

                          compound than TBT, has only been detected at low concentrations in the oyster tissues.

                             When relocated to the Hanna Reef area, both oyster populations significantly

                          depurated TBT; however, the observed depuration rates were different. HRSCHR

                          oysters depurated at a rate about 30% faster than the clearance rate observed in SCHR

                          oysters. 17his is reflected in the estimated TBT half-lives for HRSCHR and SCHR

                          oysters (21 and 27 days, respectively). The same observation was made when comparing

                          half-lives for PAHs and PCBs in HRSCHR and SCHR oysters.







                                                                                                                       107












                                                                  CHAPTER VI




                                 MECHANISM OF THE UPTAKE AND RELEASE OF TRACE ORGANIC

                            CONTAMINANTS BY THE AMERICAN OYSTER (CRASSOSTREA VIRGINICA)



                          WIRODUCTION



                              The relationship between a pollutant concentration in organisms and their aquatic

                          habitat was first explained as a simple partition process across external membrane surfaces

                          (Hamelink et al., 197 1). Since then, the dynamic equilibrium between uptake from and

                          depuration to water, together with the balance between ingested and excreted matter, has

                          been widely used to explain bioaccumulation data. After the introduction of the n-octan6l-

                          water partition coefficient (Kow) to assess the pot ential of different organic compounds to

                          be bioaccumulated under equilibrium conditions, several studies have reported a

                          correlation between the concentration factors of organic contaminants in tissues and the

                          logarithms of their Kow coefficients (Geyer et al., 1982; Mackay, 1982; Pruell et al.,

                          1986). The Kow coefficient has been found to be very useful in predicting the

                          environmental partitioning of some lipophilic compounds.

                              In this chapter, the kinetics involved in the uptake and release of selected trace organic

                          contaminants (PAHs, PCBs, including planar congeners, and TBT), as well as their

                          concentration factors by American oyster (Crassostrea virginica) during transplant

                          experiments, are reported. In the following sections, Ship Channel, Hanna Reef,

                          transplanted Hanna Reef-to-Ship Channel, transplanted Ship Channel-to-Hanna Reef and







                                                                                                                      109



                          relocated Hanna Reef-to-Ship Channel-back to-Hanna Reef oysters are refered as SC,

                          HR, HRSC, SCHR and HRSCHR oysters, respectively.



                          WCEAMSM OF BIOCONCENTRATION




                          Kinetics

                              Bioconcentration is defined as the balance between uptake and depuration processes,

                          which may proceed by first order kinetics characterized by the rate constants ku and kd,

                          respectively (Shaw & Connell, 1984). The bioconcentration factor (BCF) is defined as

                          the proportionality constant relating the concentration of a chemical in water to the

                          concentration in an aquatic organism at steady state equilibrium.

                              Ile following characteristics describing the kinetics of bioconcentration using a single

                          compartment model was adapted from Connell (1990). The one-compartment approach is

                          the mathematical expression of the hydrophobicity model, which considers

                          bioconcentration as the partitioning of a chemical between the exposure media and the

                          lipidic pools of an organisms, and vice versa, with no physical barriers (Barron, 1990).

                          The general first-order equation that describes the uptake and depuration of lipophilic

                          compounds, such as PAHs and PCBs, is expressed by


                                                            dCddt = ku Cw - kd Ct                             (1)


                          where CL is the concentration in the organism at time = t and Cw is the concentration in

                          water. Since the net amount of an analyte in the water represents a large reservoir

                          compared to the relatively lower amount taken up by organisms, Cw can be regarded as

                          constant. By integration and rearrangement


                                                      Ct = (ku/kd )Cw(l - e-kdt) + Ce-kdt                     (2)







                                                                                                                               109




                            where Cto is the initial concentration in the organism. This equation predicts that Ct will

                            increase in concentration with time and with a declining rate of increase. Thus, at time

                            infinity, t.


                                                                    Ct.= ku/kd CW                                      (3)


                            and


                                                                 CtjCw = kw'kd = Kb                                    (4)



                            where Kb is the bioconcentration factor (BCF). Similarly, the BCF can be calculated

                            from equation (1) when uptake and depuration are in equilibrium, i.e. at t = infinity


                                                              dCVdt = 0 = ku Cw - kd Ct.                               (5)


                                The theoretical time period to reach equilibrium occurs when e-kdt is zero, which is
                            when t is infinity. However, effective equilibrium can be considered to be reached at-teq

                            when Ct is 0.99 of the concentration value at infinity. Thus, from equation (2)

                                                            Cteq = (ku/kd) Cw (I - e-kdL--q)                           (6)

                                                                CLeq = 0.99 (kulkd) Cw                                 (7)


                            From equations (6) and (7)


                                                                   0.99 = I - e-kdteq                                  (8)


                            and


                                                                     teq = 4.605/kd                                    (9)







                                                                                                                         110



                           Because of the lenghts of time required for transplanted oysters to reach a concentration

                           equal to 99% the equilibrium concentration, a more time-realistic approach would be to

                           consider the time to attain 90% of the equilibrium concentration for organic contaminants.

                           Equation (9) is then modified to


                                                                  tg()%= 2.303/kd                               (10)


                               If exposure to the compound is terminated by transfer to uncontaminated water or,

                           more realistically, to a site were environmental concentrations are negligible, then C,, can

                           be regarded as zero and


                                                                  dCVdt = -kd Ct                                (11)


                           Ibis indicates that during exposure, both uptake and depuration were operating, but now,

                           in very low concentration or uncontaminated water, uptake can be neglected. By

                           integration

                                                                  Ct = Cto e-kd t                               (12)


                           or


                                                           log Ct = log Cto - kd t/2.303                        (13)


                           where Cto is @ow the initial concentration at time zero for the depuration period. This

                           equation shows that as t increases Ct declines, but the rate of decline decreases with
                           increasing time. Also, since Cto and kd are constants, log C, is linearly related to time.
                           When half of the initial compound has been cleared, then Ct= Ctd2 and the half life, tj/2,

                           is represented by










                                                    t1/2 = log 2 (2.303/kd) = 0.693/kd                  (14)


                            The kinetic parameters obtained for PAHs, PCBs, planar PCBs and T]3T are given in

                        Table 7. Concentration factors for PAHs and PCBs were calculated comparing the

                        concentrations measured in HRSC and SC oyster tissues at the end of the seven-week

                        exposure period and the average concentrations encountered in water samples (Tables A-

                        2, A-3, A-6 and A-7, Appendix).



                        Polynuclear aromadc hydrocarbons

                            As previously discussed in Chapter II, transplanted HRSC oysters bioconcentrated

                        most of the PAHs to concentrations that were not significantly different from the

                        concentrations encountered in indigenous SC oysters at the end of the uptake period.

                        Bioconcentration factors in both groups of oysters increased with the number of aromatic

                        rings for PAHs having two-, three- and four-rings per molecule and decreases thereafter.

                        The maximum concentration factors in both group of oysters were for pyrene, chrysene

                        and benzo(a)anthracene. The lowest values were for compounds with molecular weights

                        less than or greater than pyrene.

                            Depuration constant values for PAHs can be divided in two groups in both oyster

                        populations. The first one represents the two- and three-ring PAHs, which ranged from
                        0.0268 to 0.0297 days- I in HR oysters and from 0.0166 to 0.320 days-1 in SC oysters.

                        The second group includes the remaining PAHs with kd values ranging from 0.0439 to
                        0.0787 days- I in HR oysters and from 0.0430 to 0.0708 days- I in SC oysters. In the

                        first case, the low kd values result in longer biological half-lives and longer time to reach a

                        concentration within 10% the concentration at equilibrium. PAHs in the second group

                        had considerably shorter half-lives and reached within 10% of the equilibrium
                        concentration in a shorter period of time. Estimated PAH half-lives ranged from 9 days

















                                                                                        TABLE 7
                         Estimated Days to 90% Uptake Equilibrium (tgo%), Bioconcentration Factors (BCF), Depuration Rates (kd) and Biological Hal f-Lives (BHL)
                                              for PAHs and PCB Congeners in Hanna Reef and Ship Channel Oysters During the Field Studies.


                                                                            Hanna Reef Oysters                                   Ship Channel Oysters
                        Analytc                                 t90%     BCFa          kd        BHL      R2b                BCF         kd       BHL         R2
                                                               (days)               (days- 1)   (days)                      (days)     (days-1) (days)


                        PAHs


                        2,3,5-Trimcthynaphthalene                80      16,0W      0.0287         24      0.74           23,000       0.0320       22      0.83
                        Anthracene                               78      29,000     0.0295         24      0.67           29,000       0.0166       42      0.68
                        I-Mcthylphenanthrenc                     78      43,000     0.0297         23      0.97           60,000       0.0283       24      0.96
                        Fluoranthene                             86     310,000     0.0268         26      0.90          310,000       0.0215       32      0.69
                        Pyrene                                   35     890,000     0.0663         10      0.95          880,000       0.0557       12      0.98
                        Benz(a)anthracene                        44     450,000     0.0525         13      0.96          490,000       0.0453       15      0.99
                        Chrysene                                 41     490,000     0.0565         12      0.99          530,000       0.0439       16      0.99
                        Benzo(b)fluoranthene                     38     290,000     0.0601         12      0.95          270,000       0.0488       14      0.98
                        Benzo(k)fluoranthene                     34     340,000     0.0674         10      0.96          330,000       0.0561       12      0.98
                        Benzo(e)pyrene                           38     300,000     0.0602         12      0.97          310,000       0.0430       16      0.98
                        Benzo(a)pyrene                           29     200,000     0.0787          9      0.98          210,000       0.0708       .10     0.99
                        Perylene                                 35     140,000     0.0649         11      0.94          140,000       0.0532       13      0.99
                        Indeno[ 1,2,3-c,dlpyrene                 35      44,000     0.0665         10      0.96           42,000       0.0647       I'l     0.93
                        Dibenzo(a,h)anthracenc                   52      27,000     0.0439         16      0.93           24,000       0.0506       14      0.90
                        Benzo(g,b,i)perylene                     38     120,000     0.0610         11      0.96          110,000       0.0574       12      0.98


















                                                                                                    TABLE 7
                                                                                                     (confinued)



                                                                                       Hanna Reef Oysters                                           Ship Channel Oysters
                           Analyte                                        tgo%       BCFa          kd          BHL        R2b                  BCF           kd        BHL           R2
                                                                        (days)                   (days-1)     (days)                          (days)      (days-1) (days)


                           PcBs


                           2,2',5 (18)                                     48     110,000        0.0480          14        0.82            110,000        0.0362         19       0.93
                           2,3',5 (26)                                     73              -     0.0314          22        0.88                     -     0.0327         22       0.99
                           2,4,4' (2 8)                                    55              -     0.0419          17        0.96                     -     0.0205         34       0.93
                           2,2',3,3' (40)                                  47              -     0.0488          14        0.87                     -     0.0383         18       0.97
                           2,2',3.4  (41)                                  77              -     0.0299          23        0.83                     -     0.0127         55       0.92
                           2,2',3,5' (44)                                  91       97,000       0.0253          27        0.83              83,000       0.0153         45       0.94
                           2,2',4,5' (49)                                 131     210,000        0.0176          39        0.84            220,000        0.0114         61       0.94
                           2,2',5,5'   (52)                                88     100,000        0.0261          27        0.80            100,000        0.0155         45       0.91
                           2.3',4',5   (70)                               100     610,000        0.0235          30        0.88            740,000        0.0120         58       0.96
                           2,4,4',5  (74)                                 100     200,000        0.0231          30        0.87            220,000        0.0147         47       0.95
                           2,2',3,3',6 (84)                               123                    0.0187          37        0.84                     -     0.0087         80       0.79
                           2,2',3,4,5'/2.3,4,4',6 (87/115)                181                    0.0127          55        0.73                     -     0.0038         132      0.45
                           2,2',3,4',6 (91)                                84     370,000        0.0275          25        0.78            330,000        0.0140         50       0.89
                           2,2',3,5,5' (92)                                99              -     0.0233          31        0.89                     -     0.0108         63       0.93

















                                                                                                    TABLE 7
                                                                                                     (continued)



                                                                                      Hanna Reef Oysters                                          Ship Channel Oysters
                            Analyte                                      t90%       BCF1           kd         BHL         R2b                BCF           kd        BUL           R2
                                                                        (days)                  (days-1)     (days)                         (days)      (days- 1)    (days)

                            2.2',3',5',6 (95)                            149              -     0.0155          45        0.81                    -     0.0073        95        0.79
                            2,2'.4,4',5 (99)                             165      210,000       0.0140          49        0.88           330,000        0.0076        91        0.79
                            2,2',4,5,5'/2,2',3,4',5 (101/90)             184      160,000       0.0125          55        0.86           260,000        0.0060       116        0.78
                            2.3.3',4,4' (105)                            211      120,000       0.0109          63        0.76           140,000        0.0058       120        0.76
                            2,3,3',4',5 (107)                            100              -     0.0231          30        0.82                    -     0.0151        46        0.75
                            2.3,3',4',6/3,3',4,4' MOM)                   149      250,000       0.0155          45        0.74           330,000        0.0067       103        0.67
                            2.3',4,4',5 (118)                            242      300,000       0.0095          73        0.79           480,000        0.0023       299        0.19
                            2,2',3,3',4,4' (128)                         253              -     0.0091          76        0.75                    -     0.0030       229        0.42
                            2,2',3,4,4*,5'/2,3,3',4,5,6 (138/160)        658       46,000       0.0035        200         0.32            79,000        0.0012       595        0.11
                            2,2',3,4',5,5' (146)                         371                    0.0062        111         0.60                    -     0.0029       239        0.27
                            2,2'.3,4',5',6/2',3,4,4',5 (149/123)         435       74,000       0.0053        130         0.46           150,000        0.0016       439        0.24
                            2,2',4,4',5,5'/2,2',3,3'.4,6' (153/132)      169       8-7,000      0.0136          51        0.71           140,000        0.0068       102        0.90
                            2,2',3.3',4',5,6 (177)                       171       50,000       0.0135          52        0.83            65,000        0.0048       145        0.54
                            2,2',3,3',5,5',6 (178)                       172              -     0.0134          52        0.62                    -     0.0076        91        0.83
                            2,T,3,4.4',5,5' (180)                        167       12,000       0.0138          50        0.94            14,000        0.0049       142        0.63
                            2,2'.3.4',5,5',6 (187)                       233       61,000       0.0099          70        0.65            82,000        0.0027       258        0.56

















                                                                                               TABLE 7
                                                                                                (continued)




                                                                                  Hanna Reef Oysters                                        Ship Channel Oysters
                          Analyte                                    t90%       BCFa          kd         BHL       R2b                BCF          kd         BHL         R2
                                                                    (days)                 (days- 1)    (days)                       (days)      (days-1)    (days)


                          Coplanar PCBs


                          3,3',4,4' (77)                             291              -    0.W79          88        0.85
                          3,3',4,4',5 (126)                          360              -    0.0064        107        0.50                                -        -          -


                          Butyltin species


                          Tributyltin                                  68     72,000c      0.0251         27        0.95           78,000c       0.0202         34      0.96


                          a Bioconcentration factor    concentration in oyster tissue at the end of the uptake period / conccntration in water.
                          b R2 = square of the correlation coefficient for the regression equation to obtain kd.
                          C = estimated BCF (see text).








                                                                                                                   116



                          for benzo(a)pyrene to 26 days for fluoranthene and from 10 days for benzo(a)pyrene to

                          42 days for anthracene in HRSCHR and SCHR oysters, respectively. Most of the values

                          were, however, between 10 and 13 days for HRSCHR oysters and between 13 and 16

                          days for SCHR oysters. In general, originally uncontaminated oysters depurated faster

                          d= chronically exposed individuals.



                          Polychlorinated biphenyls

                              Bioconcentration factors for PCB congeners show approximately the same general

                          behavior discussed for PAHs. Concentration factors are higher for tetra-              and

                          pentachlorobiphenyls congeners and lower for tri-, hexa- and heptachlorobiphenyls.

                          Octa-, nona- and decachlorobiphenyls were detected at very low concentrations.

                              Ile decreasing values of kd and the increasing values of t90% and half-lives with the

                          higher degree of chlorination of the biphenyl molecule reflect the more rapid uptake and

                          release of the lower chlorinated biphenyls. Previous reports indicate that the less

                          lipophilic congeners reach an equilibrium concentration, either during uptake or

                          depuration, at a faster rate than those compounds that are more lipophilic (e.g.

                          Ellegehausen et al., 1980; Bruggernan et al., 198 1; Tanabe et al., 1987a).

                             Biological half-lives for PCB congeners in HRSCHR and SCHR oysters ranged from

                          14 to 200 days and from 19 to 595 days for congeners 2,2',5-trichlorobiphenyl (18) and

                          2,2',3,4,4',5'-hexachlorobiphenyI (138), respectively. Planar PCBs showed a slower
                          clearance rate'than other PCBs within the same homolog groups (Fig. 32). These slower

                          depuration rates are reflected in longer half-lives and time periods to reach 90% of

                          equilibrium concentrations. As in the case of PAHs, most of the bioconcentrated PCB

                          congeners were eliminated faster by originally clean oysters than by- chronically

                          contaminanted bivalves.








                                                                                                           117








                                      2



                                      3


                                              PCB 77
                                      4


                                           PCB 126
                                      5



                                      6



                                      7



                                      -8
                                      0.00       0.01        0.02        0.03         0.04        OAS
                                                                 kd (1/day)


                                      2



                                      3


                                                               PCB 77
                                      4
                               U
                               0
                              .C                                    PCB 126





                                      6



                                      7




                                      0              so             100            150            200
                                                                BHL (day)


                          Fig. 32. Depuration constant (kd) and biological half-lives (BHL) of planar PCB
                               congeners compared to ranges of values calculated for non-planar PCBs.







                                                                                                                    118




                              Several reports have suggested that bioaccumulation of PCBs by different organisms

                          might be influenced by physicochernical factors (Jan & Josipovic, 1978; Tulp &

                          Hutzinger, 197 8; Matsuo, 1980; Shaw & Connell, 1980, 1982, 1984; Opperhuizen et al.,

                          1985; Samuelian & O'Connor, 1985). Several parameters have been suggested that may

                          be suitable to measure the effect of these factors on the kinetics of bioaccumulation, e.g.

                          molar volume, parachor, steric effect coefficients.

                              Competitive partition between aqueous and nonpolar phases, e.g. lipids, as well as

                          stereochemistry appear to be significant factors influencing the uptake of these

                          compounds. As discussed earlier, maximum PCB uptake by organisms is observed for

                          congeners having four to six chlorine atoms. Low chlorinated congeners have higher

                          water solubilities and, as a consequence, lower lipophilicity. In contrast, isomers in the

                          higher homolog groups have unfavorable steric configurations (Shaw & Connell, 1984).

                          Opperhuizen et al. (1985) reported that the BCFs of polychlorinated naphthalenes and

                          biphenyls depend on molecular sizie, e.g. molecular volume and cross-sectional area that

                          are directly related to chlorine substitution patterns, rather than hydrophobicity.

                              As an example of the antagonistic effects that lipophilicity and size of the different

                          congeners have on their accumulation, the bioconcentration factors of six related PCB
                          congeners are compared in Fig. 33. Log Ko.. and total surface area (TSA X 10-20 m2)

                          values are also indicated (Hawker & Connell, 1988). These congeners have a common

                          2,4,5-chlorine distribution in one ring while one to four chlorines are sequentially

                          substituted on the second ring. It is clear that the more favorable lipophilicity/size

                          conditions for bioaccamulation are present in PCB 99. Congener 180 is the most

                          lipophilic of the six PCBs shown and also has the largest total surface area. On the other

                          hand, the smaller size of congener 74 for membrane transport into the tissue is countered

                          by its higher water solubility.







                                                                                                   119







                                                             CI CI



                                                             CI
                                   500-            tc, 11 CI    CI CI
                                           CI
                                   400             CI     CI                    CI
                                                      CI                           CI
                                        CI                               CI  C III
                             X,    3W         CI                     CI                    CI
                                           CI                        CII     CI          CI    CI
                                   200                               CA          CI CI   CI
                                   100                                  CI               CI
                                                                                              CI
                                                                                           CI

                                      0                                             -----JEML--
                     PCB Congener            74         99 118           138 153           180

                     Log K,,,              6.20       6.39 6.74         6.83 6.92        7.36
                     TSAx10-20 (M2)         246        252 262           265 267           280


                       Fig. 33. Bioconcentration factors of six selected PCB congeners in relation to their
                                                   liphophilicity and size.
                                                                                             Nk








                                                                                                                         120




                                Not only the bioconcentration of PCB congeners seems to be affected by the different

                            chlorine substitution in the biphenyl rings, but their depuration may be affected by these

                            factors. For example, Fig. 34 shows PCB congeners at different levels of chlorination

                            that have a fixed substitution pattern for all chlorines but one. The extra chlorine, in bold,

                            is sequentially substituted in para, meta and ortho positions giving three different

                            substition patterns. Also indicated in the figure are the estimated half-lives for these

                            congeners in chronically contaminated Ship Channel oysters. The experimental data

                            shows that there is a decrease in the estimated biological half-lives when the extra chlorine

                            is substituted in thepara > ortho > meta positions.



                            Tributyltin

                               Unfortunately, the lack of data on concentrations of TBT in seawater samples from the

                            Ship Channel area do not permit the calculation of a bioconcentration factor. However,

                            when the limit of detection of the analytical method for seawater is used to calculate the

                            bioconcentration factor, the minimum value can be estimated. The detection limit for TBT
                            in seawater is 5 ng Sn L-1; this gives a bioconcentration factor for transplanted and

                            indigenous oysters, on a dry weight basis, on the order of 72,000 and 78,000 at the end

                            of the exposure period, respectively. On wet weight basis, these estimated values convert

                            to 9,000 and 9,750, respectively, which compare well with previously published

                            concentration factors in mussels (up to 5,500; Laughlin et al., 1986) and oysters (up to

                            6,000; Waldock et al., 1983).

                               Depuration constants for TBT in newly and chronically contaminated oysters were
                            0.0251 and 0.0202 days-1, respectively. These values compare well with those

                            encountered for the lower molecular weight PAHs and PCBs. Similarly to those organic

                            contaminants, the estimated half-life for TBT in originally uncontaminated HR oysters (27





                                                                                                                    121












                                       cl     C1                                          cl     C1
                                  (D-QCI                                             &_O
                                  C1    PCB 49                                       C1   PCB 52      C1
                                    BHL = 61 Days                                      BHL = 45 Days




                                       C1     C1 C1             C1      C1 C1             C1     C1 C1
                                  a_OCI                    &_O 0-0
                                  C1                       C1           C1           C1               C1
                                        PCB 87                   PCB 95                   PCB 92
                                    BHL = 132 Days           BHL = 95 Days             BHL = 63 Days




                                  C1          C1 C!        C1           C1 C1        C1          C1 C1
                               CIO-OCI CIC)_O                                      CIO-0
                                                                        cl                            CA
                                        PCB 105                  PCB 110                  PCB 107
                                    BHL = 120 Days           BHL = 103 Days            BHL = 46 Days




                                       C1     C1 C1             C1      C1 C1             C1     C1 C1
                               C1 O_Q                cl C1 C@_Q                   C1  C)_@
                                  C1                       cl        .  C1            C1              cl
                                        PCB 138                  PCB 149                  PCB 146
                                    BHL = 595 Days           BPL = 439 Days            BHL = 239 Days


                              Fig. 34. Relationship between chlorine-substitution patterns in PCBs and their
                                                depuration half-lives. See text for explanation.








                                                                                                                   122




                         days) was lower than the corresponding value for chronically exposed individuals (34

                         days).



                         The Octanol-to-Water Partition Coefficient

                             The octanol to water partition coefficien (Kow) is defined as:


                                                               Kow = CC/CW                                  (15)


                         where CO and Cw are the concentrations of the analyte in n-octanol and water,

                         respectively. Although many organic solvents have been used for this purpose, n-octanol

                         is considered to be the best surrogate for organism lipids. Since the introduction of the

                         Kow partition coefficient in early 1960s (Hansch & Fujita, 1964), it has been used in

                         numerous studies to explain the concentration of different organic compounds in

                         biological tissues. The observed bioconcentration factor, or more commonly its log

                         value, is related to log Kow by the following equation


                                                            log Kb = a Kow + b                              (16)



                         If n-octanol behaves as a perfect surrogate for organism lipids, the constant (a) should be

                         equal to 1. A deviation from unity indicates how much octanol differs from biological

                         lipids.

                             Fig. 35 shows the log of the calculated bioconcentration factor of individual PAHs or

                         selected PCB congeners in both oysters populations plotted against the log of their
                         octanol-to-water coefficients, respectively. Values -of the log of the PAH and PCB

                         octanol-to-water partition coefficients are from Isnard and Lambert (1989) and Patil

                         (1991), respectively. The plots of the log of calculated concentration factors versus log
                         Kow have bell shaped curves. In general, an increase of the bioconcentration factors is








                                                                                                                               123







                                                    Polynuclear Aromatic Hydrocarbons
                                           1000000.

                                      U


                                      U
                                           1000007





                                             10000-


                                                               :
                                                               0
                                                               0                             0 Hanna Reef Oysters
                                                               0                             0 Ship Channel Oysters
                                             1000                              ....................             ......
                                                3.0            4.0           S.0          6.0          7.0           8.0

                                                                               Log Kow


                                          1000000.  Polychlorinated Biphenyls


                                                                                                 0
                                      16.
                                      q                                           a    0 0
                                                                                        0
                                                                      0                               0
                                           1000DO                                                     0
                                                                                               0


                                                                                                    a
                                      15

                                      0             0 Hanna Reef Oysters
                                      to            0 Ship Channel Oysters
                                            10000 1 - - - - r- .-r- .       --r - r @.                -  I . - . -I
                                                S.0            5.5           6.0          6:5          7.0           7.5

                                                                               Log Kow


                                    Fig. 35. Bioconcentration factors of polynuclear aromatic hydrocarbons and
                                  polychlorinated biphenyls calculated for transplanted Hanna Reef and indigenous
                                Ship Channel oysters during the exposure period Versus log octanol to water partition
                                                                    coefficients (Kow).








                                                                                                                      124




                          observed until log Kow reaches about 6, then there is a decline for the more lipophilic

                          compounds with high Kow. Dobbs & Williams (1983) indicated that compounds with

                          Kow greater than 6 exhibit a decrease in their lipid solubility. These compounds, often

                          referred as "superlipophilic" were redefined by Connell (1990) as "superhydrophobic."

                              A departure from the predictive relationship (16) has been observed in other studies

                          (e.g. Oliver, 1984, 1987). Hawker & Connell (1985) have indicated that the little

                          attention devoted to the time required by highly lipophilic chemicals to reach equilibrium

                          might result in underestimated kd values which cause the observed change of the slope in

                          the plot. They estimated that the necessary time for "superhydrophobic" analytes to attain

                          an equilibrium concentration in exposed organisms range from a minimum 0.5 years, for

                          log Ko.. = 6, up to 12 years, for log K0,, = 8. That study, however, was done by

                          exposing uncontaminated organisms in the laboratory to different organic compounds.

                              Besides the fact that extrapolations of laboratory produced data to real world situations

                          are not always possible, and in most cases inaccurate, this extrapolation is further

                          complicated if the uptake of these xenobiotics by an uncontaminated adult organisms is

                          compared to the uptake by organisms that are developing in a chronically contaminated

                          area. It seems obvious that tissues and lipid pools being formed by juvenile organisms in

                          chronically contaminated environments will have a better chance to truly incorporate

                          xenobiotic compounds than have tissues and lipid pools already formed in uncontaminated

                          adult individuals later exposed to the same xenobiotic compounds.

                              In the present study, Ship Channel oysters have been chronically exposed to the high

                          xenobiotic concentrations present in the Ship Channel area since the earliest stages of their

                          lives. With average lengths between 7 and 9 cm, the oysters used in this study were adult

                          organisms at the time of sampling and the analyte concentrations in their bodies can be

                          assumed to represent the equilibrium concentration at infinity (t.). Because of the
                          similarities in the shapes of the curves obtained for SC and HRSC oysters, it is clear that








                                                                                                                   125



                          less than two months are needed for newly exposed oysters to reach equilibrium

                          concentrations that are, in general, comparable to those encountered in chronically

                          exposed individuals.

                             Table 8 compares the relationships between log Kd and log Kow (16), obtained for this

                          study with previuosly reported works. Since the linear relationship between log Kb and

                          log Kow does not exist for log Kow values higher than 6, values for constants a and b are

                          commonly calculated considering only log Kow values up to 6. Connel & Hawker (1988)

                          have suggested that octanol is not a good surrogate for "superhydrophobic" compounds

                          (i.e. those with log Kow > 6) and, therefore, the concentration of these compounds by

                          organisms can not be accurately predicted from their log Kow values.



                          The Two-Compartment Model Approach

                             In depuration studies, it is also important to understand the effects that partitioning

                          among different body compartments might have on the elimination of accumulated organic

                          contaminants. The observed differences in depuration rates and, consequently, in the

                          half-life estimations between HRSCHR and SCHR oyster populations seems to indicate

                          that at least a two compartment model rather than the single compartment approach would

                          be more accurate in describing the depuration kinetics in exposed oysters. The two

                          compartment model, with the first compartment representing a peripheral system and the

                          second a central system, was described by Moriarty (1975). Briefly, the initial rapid

                          exchange across external membranes is followed by a slower but more persistent

                          accumulation in fatty tissues through the circulatory system. Chronic, or long term,

                          exposure would result in accumulation of organic xenobiotics in deeper deposits of lipids

                          stored as energy reserves. In this study, for example, xenobiotic chemicals may be better

                          partitioned between both compartments in chronically contaminated SC oysters than in

                          newly exposed HRSC oysters. If the accumulation of organic xenobiotics in bivalves is








                                                                                                                                 126








                                                                            TABLE8
                                         Characteristics of the Relationships Between log Kb and log Kow for
                                       Bioconcentration of Trace Organic Contaminants in Different Organisms.


                                Analytes         n       a         b     Organism           Reference


                                PAHs             22     0.78    -0.35    fish               SchUdrmann & Klein (1988)
                                PAHs             30     0.95    -1.06    fish               Connell & SchUUrmann(1988)
                                PAHs              6     0.97    -1.40    mussels            Pruell et al. (1986)
                                PAHs             13     1.17    -0.88    oysters (SC)       This study
                                PAHs             13     1.15    -0.77    oysters (HR)       This study


                                Crude oil        14     0.49     1.03    oysters            Ogata et al. (1984)


                                PCBs              4     0.59     1.73    mussels            Pruell et al. (1986)
                                PCBS              7     0.69     1.22    oysters (SQ        This study
                                PCBs              7     0.65     1.46    oysters (HR)       This study


                                Pesticides        8     0.70    -0.26    alga               Ellegehausen et al. (1980)
                                Pesticides        8     0.83    -1.71    fish               Ellegehausen et al. (1980)


                                Organics         16     0.86    -0.81    mussels            Geyer er al. (1982)








                                                                                                                     127



                         the result of a simple partition between tissues and seawater, then the elimination of the

                         source of contamination should reverse the process. Within the scope of the two

                         compartment model, tissues with low lipid contents, i.e. muscle and mantle, are generally

                         reported to have relatively lower tissue burdens than those with higher lipid levels, i.e.

                         gonads and gills (e.g. Laughlin et al., 1986). Clearly, with two different compartments

                         capable of accumulation of organic xenobiotics, kd values in exposed oysters can no

                         longer represent the simple partition between oyster and ambient seawater but a more

                         complicated and longer process involving different equilibrium constants among the

                         compartments and with the environment.



                         Depuration versus Degradation

                             Biotransformation of organic compounds into more polar and, therefore, more soluble

                         metabolites decreases the equilibrium level of the accumulated chemicals by increasing the

                         rate of depuration. Thus, the observed kd constants for PAHs and TBT might be a

                         combination of at least two constants, the physical partition rate between the oyster tissues

                         and ambient seawater and the biological breakdown rates to more polar compounds. This

                         will result in an increase of the clearance rate beyond that due solely to the physical

                         process described in the preceding sections.

                             Although early reports indicated that bivalves could not metabolize petroleum

                         hydrocarbons (e.g. Lee er al., 1972; Payne & Penrose, 1975; Vandermeulen & Penrose,

                         1978), later studies have shown that bivalves are able to metabolize PAHs (e.g.

                         Anderson, 1978a, 1978b, 1979; Payne & May, 1979; Stegeman, 1980). However, the

                         metabolic rates are relatively lower than those observed in other marine animals. For

                         example, Anderson (1978a) detected comparatively low concentrations of aryl

                         hydrocarbon hydroxylase, an enzyme inducible by exposure to benzo(a)-pyrene, in the

                         digestive gland of oysters. Similarly, metabolism of TBT has been shown by Lee (1985,








                                                                                                                   128




                          1986). Lee (1985) reported that after three days exposure 10% of the radioactivity of the
                          applied [14C]TBT was found in the digestive gland of oysters in the form of DBT and

                          other more polar metabolites. Other biodegradation studies have shown that DBT, a more

                          polar compound than TBT, was the major breakdown product of TBT, whereas MBT

                          was detected at very low concentrations (Maguire, 1984; Seligman et al., 1986). In the

                          case of PCBs, there is no report that indicates that bivalves are able to metabolize these

                          compounds.



                          CONCLUDING REMARKS



                             Bioconcentration factors (BCF) for PAHs and PCBs increased with the increasing

                          octanol-to-water partition coefficient up to a value of Kow around 6 and decreased

                          thereafter. Maximum BCF were observed for four-ring PAHs (e.g. pyrene, chrysene and

                          benzo(a)anthracene) and for PCB congeners having four and five substituted chlorines.

                             In general, depuration of PAHs was faster than the clearance rates observed for PCB

                          congeners. Bioconcentration and release of different PCB congeners seemed to be more

                          affected by physicochernical factors such as molecular size and chlorine substitution

                          patterns than by hydrophobicity, Thus, the magnitude of the accumulation of

                          hydrophobic organic compounds by oysters is not exclusively determined by the contents

                          of lipids in the organisms as previously speculated.
                             The most commonly reported distribution profile of PCB congeners in different

                          organisms is similar to that encountered in the commercial PCB mixture Aroclor 1254 or

                          in mixtures of Aroclors; 1254 and 1248 or 1260. This might point to these mixtures as the

                          most probable sources of the PCB congeners in different organisms. However, as a

                          consequence of physicochemical factors that discriminate against the uptake of different

                          congeners, the organisms may present a distribution of PCB congeners similar to that








                                                                                                                    129




                         found in Aroclor 1254 or in mixtures of Aroclors 1254 and 1248 or 1260 even if the

                         organisms are exposed to a more complete suite of PCB congeners in the environment.

                         Ile influence of these physicochernical factors in bioaccumulation is particularly evident

                         in the case of planar PCB congeners. Compared to other PCBs within the same level of

                         chlorination, planar congeners take a longer time to equilibrate into the lipid pools of the

                         oysters (t90%). Similarly, the time needed for depuration of these from the oyster tissues

                         was longer and this is paralleled by their significantly longer biological half-lives.

                             In general, TBT showed a biological half-life slightly longer than those observed for

                         most PAHs, comparable to the values calculated for low molecular weight PCB congeners

                         and significantly shorter than the half-lives estimated for most high molecular weight PCB

                         congeners.

                             PAHs, PCBs and TBT were, in most cases, depurated faster by newly contaminated

                         oysters than by chronically exposed individuals. A two-compartment model seems to be

                         more appropriate to explain this phenomenon than a single one.







                                                                                                                  130











                                                              CHAPTER VII




                            SIMULTANEOUS UPTAKE AND DEPURAnON OF PAHs AND PCBs BY THE

                                          AMERICAN OYSTER (CRASSOSTREA VIRGIMCA)



                          IN'17RODUCTION



                             PCBs and PAHs are known to be highly toxic to marine organisms (Hargis er al.,

                          1984; Malins et al., 1984, 1987) and interactions between the two groups of contaminants

                          are known to occur. PCBs, for example, can affect the toxicity of PAHs. Hawkes

                          (1979) observed a more severe intestinal sloughing in marine chinook salmon when

                          simultaneously exposed to PCBs and petroleum incorporated in food relative to separate

                          exposures at similar concentrations. PCB exposure induces in vitro hepatic metabolism

                          and DNA binding of benzo(a)pyrene in rainbow trout (Egaas & Varanasi, 1982).

                             Not only is the toxicity of these xenobiotics affected by PAH-PCB interactions but

                          also their biological fate. ne availability of PCBs to benthic organisms, for example, is

                          reduced by the presence of oil in the substrate (Meier & Rediske, 1984). A prior
                          exposure of Coho salmon to Aroclor 1254 substantially altered the biological disposition
                          of [14C]-labeled dimethylnaphthalene in the fish by increasing the levels of
                          dimethy1naphthalene metabolites (Collier et al., 1985). Bioaccumulation of [14C]-
                          naphthalene by oysters decreased with the simultaneous exposure to [14C]-labeled PCBs
                          ,and 3H-benzo(a)p  yrene (Fortner & Sick, 1985). The same study indicated that
                          accumulation of a (14C]-labeled PCB mixture by oysters was not always antagonistically







                                                                                                               131




                        affected by simultaneous exposure to the three contaminants. Tissue accumulation of
                        [3H]-benzo(a)pyrene was not significantly affected. It has also been shown that
                        simultaneous exposure of English sole to sediment- associated [3H]-benzo(a)pyrene (BaP)
                        and [14C]-PCBs significantly increased the concentrations of BaP-derived radioactivity

                        and decreased the concentrations of PCB-derived radioactivity in some tissues (Stein et

                        al., 1984). Several other studies have demonstrated PCB induction of many of the

                        enzymes responsible for the metabolism of PAHs in different aquatic species (Moore er

                        al., 1980; Spies et al., 1982; Anderson, 1985; Livingston, 1985).

                            In this chapter the uptake and depuradon of selected PAHs and PCBs by the American

                        oyster (Crassostrea virginica), exposed in the laboratory to particle-associated PAHs,

                        PCBs and PAHs plus PCBs, are discused.



                        SIMULTANEOUS EXPOSURE TO PAHs AND PCBs: A LABORATORY STUDY



                        Aquarium Exposure

                            The aquarium exposures were conducted simultaneously with the transplant

                        experiments in Galveston Bay (Chapters 11 and III). Oysters collected by dredge from the

                        Hanna Reef area were transfered as soon as possible to 40 1 glass aquariums and adapted

                        to laboratory conditions for 7 days prior to the experiments. One hundred and twenty

                        oysters were exposed in three aquariums, forty organisms per aquarium, to particles

                        containing PCBs, PAHs and both PCBs and PAHs. Kaolin (Al2H2Si2O8.H20), which

                        was found to have benefical effects on oystes growth (Langdon & Siegfried, 1984), was

                        used as the adsorbant for PCBs and PAHs in this study. A fourth aquarium was used as

                        a control. Uptake experiments were perfon-ned at one dosing level. The aquarium set-ups

                        were as follows*.








                                                                                                                132



                         Aquarium A. Oysters were exposed to uncontaminated suspended particles at a nominal
                            concentration of 10 mg 1-1.
                         Aquarium B. Oysters exposed to particle-associated PCBs. Nominal concentrations of
                            suspended particles and total exposure PCBs were 10 mg 1-1 and 10 Ag g-1,
                            respectively. Nominal aquarium total PCB concentration was 0.10 gg 1-1

                            (approximately 0. 1 ppb).
                         Aquarium C. Oysters exposed to particle-associated PAHs. Nominal concentrations of
                            suspended particles and total exposure PAHs were 10 mg 1-1 and 240 Ag g-I

                            respectively. Nominal aquarium total PAH concentration was 2.4 gg

                            (approximately 2.4 ppb).

                         Aquarium D. Oysters exposed to particle-associated PCBs and PAHs. Nominal

                            concentrations of suspended particles and total exposure PCBs and PAHs were 10 mg
                            1-1, lOgg g-I and 240 gg g-1, respectively. Nominal aquarium total PCB and PAIH
                            concentrations were 0. 10 gg 1- 1 (0. 1 ppb) and 2.4 gg V 1 (2.4 ppb), respectively.


                            Ile general experimental set up is shown in Fig. 36a. Each aquarium was designated

                         to use recirculated seawater simulating a flow-through system (Fig. 36b). Briefly,

                         seawater was recirculated by gravity through an activated charcoal-glass wool-

                         polyurethane foam filter and air pumped back into the aquarium. Activated charcoal and

                         polyurethane foam plugs act as solid adsorbant retaining dissolved PCBs and PAHs as

                         well as gases and metabolic products from the test organisms (Gesser et al., 1971; Basu

                         & Saxena, 1978; Afghan et al., 1984). Activated charcoal and foam plugs were changed

                         daily. Foam plugs were washed with water, extracted three times with acetone and air
                         dried prior to their, use in the filtering systems. PCBs, PAHs and PCBs plus PAHs,
                         adsorbed onto particles at environmental realistic concentrations, were pumped with a

                         peristaltic pump (Fig. 36c) and mixed with the seawater entering the aquariums after



































                                                              A-










                                                                    '#4






                                                                        Air




                                                                                                                             M



                                                               IL


                                           Fig. 36. General laboratory sct-up (a), details of an aquarium and water recirculation systent (1)), (1
                                                               and feeding system (c), and oysters used during the experiment (d).







                                                                                                                   134



                          aeration to prevent losses of the most volatile contaminants during this process. A
                                                                                                                                0'
                          different line out of the peristaltic pump was used to feed the oysters. The bivalves were

                          continuously fed with a mixture of two algae, Thalassiosira fluviatilis and Isochrysis                r-

                          galbana, raised on an f/2 algae food mixture. Temperature, pH, salinity, suspended

                          particles and recirculation flow for each aquarium were monitored daily. Uptake studies

                          lasted one month. Groups of five oysters, water and suspended particle samples were

                          collected from each aquarium during the 3rd, 7th, 15th, and 30th days after the

                          experiments started. A total of 20 oysters per aquarium were sampled during uptake

                          experiments. Fig. 36d shows the sizes of the laboratory exposed oysters.

                              For depuration studies, groups of five oysters were sampled from each aquarium

                          during the 3rd, 7th, 15th, and 30th days after the contaminant inputs were discontinued

                          and the organisms were transferred to clean seawater. A total of 20 oysters per aquarium

                          were sampled during the depuration period. Water samples from each aquarium were also

                          collected.

                              Temperature, pH, salinity and recirculation flow for each aquarium were checked
                          daily. With an average flow of approximately 5 1 h- I and a volume of water in the

                          aquariums of 40 1, 95% of the water in the aquariums was filtered every 24 h (Spague,

                          1969). When necessary, the salinity of the aquarium was adjusted with HPLC water to

                          the starting value of 18%o. Particle concentrations in the aquariums were in the range of
                          6.4 to I I mg 1- 1, a concentration range commonly reported for coastal marine

                          environments (see, for example, Cadee, 1982; Colijn, 1982). Mortality of the exposed

                          oysters was  minimal throughout the experiment (one oyster in Aquarium D). Control

                          oysters showed little change in analyte concentrations during the 60-day exposure and

                          depurati on experiments. The reported concentrations correspond to five pooled oysters.







                                                                                                               135



                         Extraction,fractionation and instrumental analyses of PAHs and PCBs

                            The extraction and fractionation, as well as instrumental analyses of PAHs and PCBs

                         were discussed in Chapters II and III, respectively.



                         Polynuclear Aromatic Hydrocarbons

                            PAH concentrations measured in oysters collected from Aquariums A (control), C

                         (PAHs), and D (PAHs plus PCBs) during the uptake and depuration experiments are

                         plotted in Fig. 37. In general, exposed oysters rapidly accumulated four- and five- and

                         some three-ring compounds. In this molecular range, some PAHs reached an apparent

                         steady state concentration 10 days after the start of the experiments (e.g., I-

                         methylphenanthrene and pyrene). Most of the analytes, however, had not reached a

                         concentration plateau after 30 days (e.g., benz(a)anthracene, chrysene, benzo(e)pyrene

                         and perylene). Two- and most of the three-ring PAHs were detected at low

                         concentrations in both groups of oysters.

                            The PAHs accumulated in highest concentration were the same in organisms exposed
                         to PAHs alone or simultaneously to PAHs plus PCBs (Fig. 38). However,

                         concentrations of individual PAHs in oysters exposed solely to PAHs were, at the end of

                         the 30-day exposure period, lower than the concentrations encountered in oysters exposed

                         to the mixture PAHs plus PCBs. The PAHs accumulated to the highest concentration

                         after 30 days in oysters exposed only to PAHs were: ben zo(b)fluoranthene,

                         benzo(e)pyrene, benz(a)anthracene, chrysene and indeno-[1,2,3-c,d]pyrene whereas the

                         accumulation order found in second group of oysters was: benzo(b)fluoranthene,
                         benz(a)anthracene, benzo(e)pyrene, chrysene and indeno[1,2,3-c,d]pyrene. Most of

                         these PAHs were also preferentially accumulated by HRSC and SC oysters under field
                         conditions. Therefore, the laboratory uptake confirms the environmental findings. When

                         exposed to a wide molecular weight range of PAHs, i.e. two- to six-ring compounds,










                                         1000. Benz(a)anthracene                                                         1000. Chrysene


                                          fool                                                                            100,


                                                                                                                                                                               Aquarium A
                                                                                              Aquarium A           at
                                           to-                                                Aquarium C                  10                                                   Aquarium C
                                                                                                                                                                               Aquarium D
                                                                                              Aquarium D





                                   U                                                                               U
                                           A -                              4
                                             0         10        20        30        40        50         60                0         to         20        30        40        so         60

                                                                      Time  (days)                                                                   Time   (days)

                                              Denzo(e)pyrene                                                                 Peryleve
                                        1000                                                                            loon
                                                                                                                                                                               Aquarium A
                                                                                                                                                                               Aquarium C
                                         100                                                                             100                                                   Aquarium D
                                                                                                                   V
                                                                                              Aquarium A           a
                                                                                              Aquarium C
                                          10                                                                               to,
                                                                                              Aquarium S









                                             0         to        20        30        40        50         60                0         to         20        30        40        so         60

                                                                      Time (days)                                                                    Time (days)
                                Fig. 37. Concentrations of selected polynuclear aromatic hydrocarbons in tissues of oysters during exposure to particle-
                                  associated PAHs alone (Aquarium Q and PAHs + PCBs (Aquarium D) and following transplant to contaminant-free
                                                                               aquariums. Aquarium A was tised as control.





                                                                                                                       137








                                                                                                    Aquarium C
                                            Naphthalene
                                   2-Methylnaphthalene                                              Aquarium D
                                   I-Methylnaphthalene
                                              Biphenyl
                               2,6-Dirnethy1naphthalene
                                        Acenaphthylene
                                          Acenaphthene
                             2,3,5-Trimethy1naplithalene
                                              Fluorene

                                          Phenanthrene

                                            Anthracene
                                 1-Methylphenanthre e

                                           Fluoranthene
                                                 Pyrene
                                     Benz(a)antliracene
                                              Chrysene
                                  Benzo(b)(luoranthene     . . . . . . . . .
                                  Benzo(k)fluoranthene            ..........
                                         Benzo(e)pyrene
                                        Benzo(a)pyrene
                                              Perylene
                                 Indenoj1,2,3-c,djpyrene
                                 Dibenz(a,h)anthracene
                                    Benzo(g,hJ)perylene

                                                        0      100 200 300 400                 500     600     700


                                                                  Concentration (ng/g, dry wt.)


                         Fig. 38. Concentrations of individual polynuclear aromatic hydrocarbons in tissues of
                         laboratory exposed oysters after the 30-day exposure period to parficle-associated PAHs
                                              (Aquarium Q and PAIIs + PCBs (Aquarium D).







                                                                                                                        138




                            oyster preferentially bioconcentrate those analytes having four and five rings. This

                            preferential uptake is unrelated to the presence or absence of PCBs.

                                When the input of contaminants was stopped, both oyster groups showed statistically

                            significant depuration of most of the PAHs accumulated during the first phase of these

                            experiments. However, as previously discussed for environmentally contaminated

                            oysters, they were unable to reach the low concentrations encountered for some of these

                            analytes before the exposure. Fig. 39 compares the final concentrations of PAHs at the

                            end of the 30-day depuration period in oysters exposed to particle-associated PAHs and

                            PAHs plus PCBs. At the end of the 30-day depuration period, the total PAR loads in

                            both groups of exposed oysters were dominated by heavier molecular weight PAHs, i.e.

                            four- and five-ring compounds.

                               Oysters that had been exposed simultaneously to PAHs and PCBs depurated PAHs at

                            a faster rate than oysters exposed only to PAHs. Calculated half-lives for both groups of

                            oysters are shown in Table 9. In PAH exposed oysters, the estimated half-lives ranged

                            from 9 (fluoranthene and pyrene) to 25 (ben zo (b)fl uoranthene/benzo(k)fl uoranthene)

                            days. Comparatively, PAHs plus PCBs exposed oysters yielded PAH half-lives ranging

                            from 6 (pyrene) to 15 (benzo(e)pyrene) days. Most of the values were, however, in the

                            range 15 to 17 days and 8 to 10 days, for the first and second groups of oysters,

                            respectively.

                               In general, the estimated half-lives are in good agreement with previously published
                            values and with the calculated clearance rates for HRSCHR and SCHR        oysters presented

                            in Chapters II and VI; however, some differences exist. First, it is evident that, except for

                            2,3,5-trimethylnaphthalene, anthracene, 1-methylphenanthrene and fluoranthene, the half-

                            lives calculated for oysters exposed simultaneously to a mixture of PAHs and PCBs

                            compare better to the environmental half-life values estimated for HRSCHR oysters than

                            the values obtained from the oysters exposed only to PAHs. This is consistent with the







                                                                                                                                139








                                                                                                           Aquarium C
                                               Naphthalene
                                       2-Methyinaphthalene                                                 Aquarium D
                                       I-Methylnaphtha)ene
                                                  Biphenyl
                                   2,6.Dimethylnaphthalene
                                            Acenaphthylene
                                              Acenaphthene
                                2,3,5.Trimeth3,lnaphthalene
                                                  Fluorene

                                              Phenanthrene

                                                Anthracene
                                     1-Methylphenanthrene
                                              Fluoranthene

                                                     Pyrene
                                         Benz(a)anthracene
                                                  Chrysene
                                      Benzo(b)nuoranthene
                                      Benzo(k)nuoranthene
                                            Benzo(e)pyrene
                                            Betizo(a)pyrene
                                                  Perylene
                                   Indenol 1,2,3-c,dlpyrene
                                     Dibenz(a,h)anthracene
                                       Benzo(g,h,i)perylene

                                                                               100                200                 300

                                                                       Concentration (ng/g, dry wt.)


                            Fig. 39. Concentrations of individual polynuclear aromatic hydrocarbons in tissues of
                            oysters previously exposed in the laboratory to particle-associated PAHs (Aquarium Q
                            and PAHs + PCBs (Aquarium D) after the 30-day depuration period in contaminant-free
                                                                       aquariums.







                                                                                                               140








                                                                  TABLE9
                               Biological Half-Lives of PAHs in Crassostrea virginica Oysters Exposed in the
                              Laboratory to Particle-Associated PAHs Alone (Aquarium Q and PAHs + PCBs
                                                               (Aquarium D).


                             Analyte                                            Biological Half-Lives (R2)a
                                                                          Aquarium C               Aquarium D


                             2,3,5-Trimethylnaphthalene                    16(0.75)                  10(0.91)
                             Anthracene                                    16(0.68)                   8(0.89)
                             I-Methylphenanthrene                          16(0.72)                   7(0.88)
                             Fluoranthene                                    9(0.78)                  7(0.85)
                             Pyrene,                                         9(0.75)                  6(0.89)
                             Benz(a)anthracene                             16(0.81)                   9(0.99)
                             Chrysene,                                     22(0.86)                  12(0.98)
                             Benzo(b)fluoranthene/
                             Benzo(k)fluoranthene                          25(0.94)                  13(0.95)
                             Benzo(e)pyrene                                21(0.93)                  15(0.98)
                             Benzo(a)pyrene                                12(0.87)                   9(0.78)
                             Perylene                                      15(0.96)                  10(0.89)
                             Indenof 1,2,3-c,d]pyrene                      10(1.00)                   8(0.78)
                             Dibenz(a,h)anthracene                         11(0.97)                  10(0.69)
                             Benzo(g,h,i)perylene                          16(0.96)                  11(0.92)

                             a R2 = square of the correlation coefficient for the regression equation.








                                                                                                                   161




                          When combined, these congeners accounted for 43.9 and 36.7% of the total PCBs in

                          oysters and sediments, respectively.



                          XPCB Congeners/Total PCB Relationship

                             Several methods have been used to quantitate PCBs in environmental samples. In the

                          past, for example, PCB concentrations have been expressed as the equivalent Aroclor

                          mixtures (e.g. Bopp er al., 198 1; Pugsley et al., 1985; Brownawell & Farrington, 1986)

                          or as their similar foreign technical formulations, e.g. Clophen (Eder et al., 1981) or

                          Phenochlor (Elder er al., 1979). An accurate determination of total PCBs in

                          environmental samples would have to be carried out with the use of each individual

                          congener as reference material (Duinker et al., 1980). With the introduction of capilary

                          columns and the availability of almost every individual PCB congener as a standard,

                          several reserchers have attempted to report total PCB concentrations as the sum of all the
                          measurable individual congeners. However, some of these' congeners are not alway          s

                          separated from other congeners on a single GC capillary column (Duinker et al., 1988a).

                          Duinker et al. (1988b) suggested a number of different congeners, in addition to those

                          recommended by ICES, that could be accurately analyzed in environmental samples.

                          These congeners cover all the levels of chlorination and satisfy the condition of good GC

                          separation on an SE-54 or similar capillary column. A variant of this approach was

                          initially used in reporting the total PCB concentrations in oyster and sediment samples

                          collected from the Gulf of Mexico as pan of the NS&T "Mussel Watch" Program.

                             During 1986 and 1987, 18 different congeners (i.e. PCB 8, 18, 28, 44, 52, 66, 101,

                          105, 118, 128, 138, 153, 170, 180, 187, 195, 206 and 209) were supplied by NIST,

                          formerly NBS, for  making quantitation standards. These congeners, which are some of

                          the major congeners found in commercial Aroclor mixtures, are among those commonly

                          reported in environmental samples. Nine of these congeners (i.e. PCB 8, 28, 52, 101,







                                                                                                                    162



                          153, 170, 195, 206 and 209), specified by NOAA, were used as reference congeners,

                          representative of a given degree of chlorination from C12 to Clio, to determine other

                          congener concentrations at each level of chlorination. Results were reported as the sum of

                          congeners within each level of chlorination and total PCB as the sum of these amounts.

                          One obvious problem with this method of quantitation is the different relative response

                          factor for each congener. Thus, a congener that does not have a standard to be directly

                          compared to might be underestimated or overestimated because of the difference between

                          its relative response factor and that of the corresponding representative congener.

                              Discussions among the different participating laboratories in this program directed to

                          improve the PCB reporting led to the adoption of an equation that relates the sum of the 18

                          individual congener concentrations in the samples with the total PCB loads. Fig. 48

                          shows, for example, the correlation encountered in oyster samples collected in the Gulf of

                          Mexico during 1986. Therefore, starting in 1988, total PCB concentrations in oyster and

                          sediment samples from the Gulf of Mexico, Atlantic and Pacific coasts, including Hawaii,

                          were estimated and reported using this new approach.

                              During the first year of the NS&T program total, PCBs ranged from 10 to 4,020 ng
                          9_1 (Sericano et al., 1990a). Nearly 95% of the samples had a total PCB load below 500
                          ng g-l. Therefore, the correlation between the sums of the 18 individual PCB congeners

                          and the total PCB concentrations in oyster samples is likely to be affected by a small

                          percentage of samples collected from heavily contaminated sites. Table I I shows

                          correlations for the same data set when ranges are chosen to eliminate the bias introduced

                          by the highly contaminated samples. For example, just eliminating the highest PCB

                          concentration measured in a sample collected near the Yacht Club, in Galveston Bay,

                          reduces the near-perfect correlation of 0.99 to 0.97. Considering samples with total PCB
                          concentrations of 500 ng g- I or lower (i.e. 95% of the samples) decreases the correlation

                          to 0.92 (Fig. 48b). Further reductions of the data set to maximum concentrations lower















                                       A
                           Q    4000,                                                                               300.

                                                                                                                    400-
                                3000

                                                                                                                    me
                                20"'.
                                                                                                                    2"'.
                                It"
                                                                     I @7,2574   JAMx RA2         0."3                                                Y = 12.777    I-7771z RA2     0.922
                                                                      = 144                                          0                                  = 137
                                     0           so@          Is'6                      2;00'         2SOO                                  IO'o                  200                   300
                                                         Total 1:    congen:rSsOO(ng1g)                                                    Total IS   congeners (ng/g)

                                 200- C




                                                                 a   a Joe   a                                      60-


                                                                                                                    40                         *0

                                                           41



                                                                     Y= 11.198 + 1.78S3z RA2      0.902
                                                                                                                                                      Y = 18-192 + 1.29531   RA2    0.491
                                                                     a=                                                                                 = 72

                                     0           20           44            60                        100              0            Is           20           30            40
                                                         Total IS    congeners (ng/g)                                                      Total 18 congeners (ng/g)


                                   Fig. 48. Relationships between the sum of 18 selected PCB congeners and the total PCB load encountered in Gulf of
                                           Mexico oysters for the first year of NOAA's National Status and Trends Program. See text for discussion.








                                                                                                                              164







                                                                         TABLE 11
                                     PCB Congeners/Total PCB Relationships in Gulf of Mexico Oyster Samples.

                                   n     Total PCBa       Fraccion            Regression equation                   R2
                                            ngg-I             %



                                                                             1986
                                  144     all data             100           YPCB=7.25+1.89ICongb                   0.99
                                  143       :52000             99            Y-PC13=6.52+1.901Cong                  0.97
                                  140       :51000             97            Y-PCB=12.29+1.79Y-Cong                 0.95
                                  137        :5500             95            YPCB=l2.78+l.78YCong                   0.92
                                  108        :5157             75            YPCB=l 1. 1 1+1.71YCong                0.80
                                  66           :586            50            I:PCB =I 8.19+1.29Y-Cong               0.49


                                                                             1987c
                                  149     all datad            99            Y-PCB--0.81+2.30ICong                  0.96
                                  140        :5300             95            Y-PCB=13.8+1.89Y-Cong                  0.81
                                  129        -<-200            87            Y-PCB=l 2.5+1.837-Cong                 0.75


                                  aupper limit of the data range corresponding to the total PCBs calculated from
                                  level of chlorination; bsurn of 18 individual PCB congeners; CBrooks et al. (1988);
                                  dtwo outliers eliminated from regression analysis.








                                                                                                                     165



                          than or equal to 157 ng g- 1 (75% of the samples) or to 86 ng g- 1 (50% of the samples)

                          will reduce the correlation coefficient to 0.80 and 0.52, respectively (Fig. 48c and d,

                          respectively). Similar correlations were reported for oyster and sediment samples

                          collected during 1987 (Brooks et al., 1988; Table 11). Joiris & Overloop (1991) showed

                          the correlations between the sum of nine of the most "classical" congeners (i.e. PCB

                          congeners 28, 52, 101, 118, 138, 153, 170, 180 and 194) and total PCBs expressed as

                          Aroclor 1254 as well as correlations between individual congeners and total PCBs in

                          particulate matter (mainly phytoplankton) and netplankton (mainly zooplankton with some

                          phytoplankton) samples collected in the Indian sector of the Southem Ocean. Although
                          no correlation factors are given in the report, coefficients of regressions (R2) between the

                          sum of the nine congeners and total PCB concentrations, estimated ftom new plots made

                          from their figures, were about 0.85 and 0.56 for particulate matter and netplankton

                          samples, respectively. Total PCB concentrations in particulate matter and netplankton
                          samples ranged from about 200 to 2900 n g g- I and from 70 to 5 10 ng g- I on a dry

                          weight basis, respectively. This data analysis indicates that the correlation between the

                          sums of individual PCB congeners and the total PCB concentrations in environmental

                          samples appears to be dependent on the total PCB load.

                             Although it has been shown that after exposure to a wide range of molecular weight

                          PCBs oysters will preferentially uptake four-, five-, and six-chlorine substituted

                          congeners (see Chapter VII), there might be differences in the residual PCB profiles

                          among oyster samples collected from different'geographical areas as a result of a variety
                          of local sources. The 1congeners/total PCB ratios calculated from the data reported by

                          Schulz et al. (1989) encountered in Aroclor mixtures 1016, 1242, 1254 and 1260 were

                          2.61, 2.86, 2.63 and 2.55, respectively. These ratios can be modified in the environment

                          as a consequence of the differential physico-chemical and biological properties of

                          individual congeners controlling their water transport, bioaccumulation, etc. Different








                                                                                                                    166



                          residual PCB compositions in oysters will obviously produce different results. For

                          example, total PCB concentrations, calculated as the sum of all measurable PCB

                          congeners, in oyster samples collected near the Houston Ship Channel area in Galveston

                          Bay over a seven-week period (see Chapter III for more details) yielded concentrations

                          that constantly were between 30 to 35% higher than the concentrations estimated with the

                          above correlation (Fig. 49). Another way to illustrate this assertion is to consider the

                          PCB, profiles encountered in uncontaminated Hanna Reef oysters when transplanted to the

                          upper Galv  eston Bay area near the Houston Ship Channel (Fig. 17, Chapter III). During

                          this experiment, low molecular weight PCBs were bioaccumulated at a faster rate than

                          congen  ers with higher level of chlorination. By the end of the 48-day exposure period,

                          the amount of total PCB estimated by the equation was up to 60% lower than the total

                          PCB load measured as the sum of all individual congeners (Fig. 49).

                              Although the transplantation experiment can be compared to an extreme case of a rapid

                          environmental PCB, contamination, similar disequilibrium between PCB concentrations in

                          oysters and environmental leves might also be a consequence of natural processes related

                          to the bivalves themselves such as spawning. It has been suggested that high variability

                          in xenobiodc concentrations in bivalves from a given location might be more related to the

                          stage of the reproductive cycle and its associated biochemical modifications than to

                          environmental changes (Jovanovich & Marion, 1987). Most organisms have a marked

                          increase in their lipid contents during gametogenesis, which is followed by a drastic loss

                          of lipidic material with the gametes at spawning (Phillips, 1986). Since most
                          hydrophobic trace organic c6ntaminants will tend to concentrate in lipid-rich tissues, such

                          as eggs, it is evident that their concentration will vary with the sexual cycle. Release of

                          hydrocarbons and   pesticides during spawning has been reported for Mytilus edulis and

                          Crassostrea virginica, respectively (Lowe et al., 197 1; Fossato & Canzonier, 1976).








                                                                                                                                                         167




                                                             2000-  Indigenous
                                                                    Ship Channel Oysters              0 Regression Equation
                                                                                                      a Sum of Individual Congeners

                                                             1500-.


                                                             100


                                                        r


                                                        cc





                                                                                         7           17           30           49
                                                                                              Sampling Day
                                                             12oo - Transplanted         s            0 Regression Equa tion
                                                                    Hanna Reef Oyster
                                                                                                      U Sum ofIndividual Congeners
                                                             1000'



                                                        r


                                                               00



                                                               4",
                                                        U
                                                        G:
                                                        U      2"




                                                                         3               7           17           30            48
                                                                                         Length of Exposure (days)

                                                               $00. Laboratory    Exposed
                                                                    Hanna Reef Oysters                0 Regression Equation
                                                                                                      0 Sum of Individual Congeners
                                                               400,



                                                               3"













                                                                         3               7           is           30            48
                                                                                         Lenght of Exposure (days)


                                       Fig. 49. Three'different examples of the bias introduced in the report of total PCB
                                       concentrations by using the regression equation (see text) compared to the total PCB
                                                    load calculated as the sum of all measurable individual congeners.







                                                                                                                168




                             It may be concluded that even though there is a reasonable correlation between the

                         sums of 18 individual PCB congeners and the total PCB concentrations in oyster samples

                         and it might provide an estimation of the total PCB load, the preceeding discussion

                         indicates that it must be applied with caution when reporting and interpreting

                         environmental data. The greatest disadvantage of this procedure is that much of the

                         information is lost when complete congener characterization of PCB residues in

                         environmental samples is not reported. This is emphasized by the fact that PCB

                         composition changes drastically as they move from one environmental compartment to

                         another.



                         Planar PCB Congeners

                             PCB congeners have been widely reported in oyster samples collected as part of this

                         program in the Gulf of Mexico (Seiicano et al, 1990a); however, the occurence of toxic

                         planar PCB congeners, i.e. 77, 126 and 169, have not until recently been reported

                         (Sericano et al., 1992).

                             The concentrations of planar congeners, as well as the concentrations of selected

                         predominant mono- and di-ortho substituted congeners and total PCBs in oyster samples

                         from sites in Galveston and Tampa Bays (Fig. 50), collected during winter 1990-1991

                         (year 4 of the NS&T program), are summarized in Table 12. In Galveston Bay, the

                         highest concentration of these planar PCBs was found in samples collected near the area

                         where the Houston Ship Channel enters the upper Galveston Bay (GBSC) and decreases

                         seaward. Ile second highest total concentration was encountered in samples from a site

                         near the, city of Galveston (GBOB). The general distribution of planar congener

                         concentrations in Galveston Bay clearly shows high values near population centers. The

                         same correlation between urban centers and concentrations of planar PCBs can be






















                                                                          tEXAS
                                                                                                                  A - TAMPA BAY OLD
                                               A                                                                  B - TAMPA BAY KMGHT
                                                                                                                  C - TAMPA BAY PAPYS,
                                                                                                                  D - TAMPA BAY NARVAJ
                                                                                                                  E - TAMPA BAY COCKR
                                                                                                                  F - TAMPA BAY AwLLET




                                                                                                                          ).A
                                                                                                            Dunedin. -
                                                                    qD D
                                                 s- LE@
                                                                                                           Clea- let.,
                                                                                                                        0         !-:Tamp







                                                              -VESTON                                                        C
                                                                                                                                     G@d
                                                           F
                                                                                            GULF             SL P@etersburg
                                                                                                            D
                                         fs-t                                                 OF
                                                                                                                               @b
                                                                                                                      PL Pmew@
                                                                                                                              e  E
                                                                                                                             4@b
                                                                                            MEXICO

                                         A - GALVESTON BAY SHIP CHAN74EL (GBSC)
                                         B - GALVESTON BAY YACHT CLUB (GBYC)
                                         C - GALVESTON BAY TODDs DUMP (GBTD)
                                         D - GALVESTON RAY HANNA REEF (GBHR)
                                         E - GALVESTON RAY CONFEDERATE REEF (GBCR)                              Anna
                                         F - GALVESTON DAY OFFATS BAYOU (GBOB)                                  Maria Island





                                  Fig. 50. NOAA's National Status and Trends sampling locations in Galveston and Tampa Bay








                                                                                                                170









                                                                  TABLE 12
                                 Planar and Total PCB Concentrations in Oysters (Crassostrea virginica) from
                                                         Galveston and Tampa Bays.


                              Sample                      Concentration of Planar PCBs            Total PCBs
                                                            77            126            169
                                                          p9 9-1         p9 9-1       p9 9-1           ng g-I


                              Galveston Bay


                              GBSC                          2,000          2,200         790        1,100ï¿½120
                              GBYC                           330            210          190           210ï¿½14
                              GBID                           140            120            54          110ï¿½18
                              GBHR                             89           110            89          50ï¿½7.0
                              GBCR                           100              94           51          77ï¿½9.6
                              GBOB                           500            400            93          160ï¿½44


                              Tampa Bay


                              TBOT                           170            320          280           55ï¿½8.5
                              TBKA                          1,500           330            84         580ï¿½230
                              TBPB                             85           100            51          75ï¿½27
                              TBNP                           260            140          150           120ï¿½31
                              TBCB                           200            290          100           49ï¿½20
                              TBMK                           ND             ND           ND            38ï¿½14



                              ND = not detected








                                                                                                                    171




                         observed in Tampa Bay. The highest concentrations were measur in samples collected

                         near Tampa (TBKA).

                             As expected from the small contributions of these planar congeners to the total

                         commercial PCB mixtures (Kannan et al., 1987; Schulz et al., 1989), these congeners

                         were detected at much lower concentrations than other mono- and di-ortho substituted

                         PCB congeners. In commercial PCB mixtures, the concentration of congener 77 is one to

                         two and three to five orders of magnitude higher than concentrations of congeners 126

                         and 169, respectively (Kannan et al., 1987). Therefore, it appears that congeners 126 and

                         169 are enriched with respect to congener 77 in oyster samples from Galveston and

                         Tampa Bays. This is not surprising since the log Kow (octanol-to-water coefficient)

                         increases with the number of chlorines substituted in the biphenyl rings (6.36, 6.89 and

                         7.42 for congeners 77, 126 and 169, respectively; Hawker & Connell, 1988). On

                         average, the sum of these three highly toxic congeners ranged from 0.26 to 0.62% and

                         from 0.31 to 1.40% of the total PCB load in Galveston and Tampa Bays, respectively.

                             In a review, Safe (1990) discussed the environmental and mechanis    tic considerations

                         behind the development of the Toxic Equivalent Factor (TEF) concept. Safe proposed

                         provisional TEF values of 0.01, 0.1 and 0.05 for planar congeners 77, 126 and 169,

                         respectively. Recently, the validation and limitations of these factors have been reported
                         (Safe, 1992). Calculated 2,3,7,8-TCDD equivalents, in pg g- 1, in oyster tissues collected

                         from Galveston and Tampa Bay, as well as their averages, are listed in Table 13. In

                         Tampa and Galveston Bays, the total 2,3,7,8-TCDD equivalents ranged from 14 to 52 pg
                         9- 1 and from 13 to 280 pg g-1, respectively. The data show that, except for the sample

                         collected near the Houston Ship Channel, oysters from Tampa and Galveston Bays are

                         similar in terms of total toxicity. Oysters collected near the Houston Ship Channel

                         (GBSQ in Galveston Bay were clearly the most toxic. Thisarea is closed to commercial








                                                                               172







                                              TABLE 13
                     2,3,7,8-TCDD Equivalents (pg g- 1) Corresponding to Non-Ortho Substituted PCB
                          in Oysters (Crassostrea virginica) from Galveston and Tampa Bays.


                     Sample                        Congener               TOW
                                           77        126      169


                     Galveston Bay


                     GBSC                   20        220        40         280
                     GBYC                   3.3        21       9.5         34
                     GBTD                   1.4        12       2.7         16
                     GBHR                   0.9        11       4.5         16
                     GBCR                   1.0        9.4      2.6         13
                     GBOB                   5.0        40       4.7         50


                     Tampa Bay


                     TBOT                   1.7        32        14         48
                     TBKA                   15         33       4.2         52
                     TBPB                   0.9        10       2.6         14

                     TBNP                   2.6        14       7.5         24
                     TBCB                   2.0        29       5.0         36

                     TBNM                   -          -         -           -








                                                                                                                    173




                         or sport oystering due to bacteria concentrations; therefore, the high PCB levels are not a

                         human health thmat.

                             As discussed earlier, congeners 77, 126 and 169 are present at trace concentrations in

                         commercial PCB mixtures and at very low concentrations in environmental samples;

                         however, their mono-ortho derivatives (e.g. congeners 105, 118, 156 and 189) may be

                         more important in terms of both TCDD-like activity and occurrence (Safe, 1984). Certain

                         di-ortho derivatives of the m,m'pp' sustitution pattern (e.g. congeners 128, 138, 153

                         and 170) are significant components of PCB residues (Duinker et al., 1988a; Schulz et

                         al., 1989; Schwartz et al., submitted). Congeners 128, 138 and 170 have reduced

                         TCDD-like activity compared to their parent planar congeners whereas PCB 153 lacks of

                         TCDD-like responses (Hansen, 1987). Safe (1990) proposed provisional TEF values of

                         0.001 and 0.00002 for mono- and di-ortho chlorine substituted PCB congeners,

                         respectively.

                             The concentrations of PCBs 105, 118,      128 and 138 as well as total PCBs in oyster

                         samples from sites in Galveston and Tampa Bays are summarized in Table 14. These

                         congeners are derivatives of planar PCB 77. Individually, the concentrations of these

                         mono- and di-ortho congeners were, as expected, one to two orders of magnitude higher

                         than planar PCB concentrations. In order to assess the environmental significance of

                         these congeners in terms of TCDD-like effects in oyster samples from Galveston and

                         Tampa Bay, the calculated 2,3,7,8-TCDD equivalents (Table 15) are compared to those

                         corresponding to planar congeners. In spite of the relatively lower toxic effect of

                         congeners 105 and 118 compared to planar PCBs, these congeners might have a

                         significant toxic impact in the environment. Most of the relative toxicity in oyster,

                         however, are due to the presence of planar PCBs (53.8 to 94.3%; Fig. 51). Contribution

                         of congeners 105 plus 118 to the total 2,3,7,8-TCDD equivalents was as high as 45.4%;

                         in contrast, the contribution of di-ortho congeners is negligible (<1.0%). The lesser








                                                                                                                              174







                                                                         TABLE 14
                                         Selected Mono- and Di-Ortho Substituted PCB and Total PCB Average
                                   Concentrations (ng g-1) in Oysters (Crassostrea virginica) from Galveston and
                                                                        Tampa Bays.


                                 Sample                                    Congener                            Total PCBs
                                                   105              118             128              138


                                 Galveston Bay


                                 GBSC              39ï¿½4.1           48ï¿½5-8         4.4ï¿½0.6           50ï¿½6.7       1,100ï¿½120
                                 GBYC              4.1ï¿½1.7          9-0ï¿½0.3        1.5ï¿½0.2           13ï¿½3.2          210ï¿½14
                                 GBTD              1.3ï¿½0.2          5.2ï¿½1.0        0.6ï¿½0.2          5.7ï¿½1.1          110ï¿½18
                                 GBHR              0.6ï¿½0.5          1.2ï¿½0.3        0.6ï¿½0.2          4.3ï¿½0.8          50ï¿½7.0
                                 GBCR              0.7-+0.6         2.8ï¿½0.2        0.7ï¿½0.3          5.0-+1.4         77ï¿½9.6
                                 GBOB              3.2ï¿½1.8          10ï¿½2.7         1.0ï¿½03           8.7ï¿½3.4          160ï¿½44


                                 Tampa Bay


                                 TBOT              0.4ï¿½0.2          2.4ï¿½1.6        0.2ï¿½0.2          4.0-+0.8         55ï¿½8.5
                                 TBKA              7.6ï¿½3.7          36ï¿½15          2.0ï¿½1.0            30ï¿½13         580ï¿½230
                                 TBPB,             0.4ï¿½0.1          3.0-+0.7       0.3ï¿½0.2          6.1ï¿½2.6           75ï¿½27
                                 TBNP              1.3ï¿½0.2          7.3ï¿½1.8        0.6ï¿½0.2          8.9-+3.1         120ï¿½31
                                 TBCB              0.4ï¿½0.2          3.0ï¿½1.1        0.2ï¿½0.2          2.8ï¿½1.2           49:L20
                                 TBMK              0.3ï¿½0.2          1.6ï¿½0.3        0.2-+0.1         3.3ï¿½2.0            38ï¿½14








                                                                                                                                             175







                                                                                 TABLE 15
                                       Average 2,3,7,8-TCDD Equivalents (pg g-1) Corresponding to Selected Mono-
                                     and Di-Ortho Substituted PCBs in Oysters (Crassostrea virginica) from Galveston
                                                                              and Tampa Bays.


                                     Sample                                Congener                                   TOW           Totala
                                                        105              118          128             138


                                     Galveston Bay


                                     GBSC               39               48              0.1            1.0               89             379
                                     GBYC               4.1              9.0          <0. 1             0.3               13              47
                                     GBTD               1.3              5.2             0.1            0.1               6.7             23
                                     GBHR               0.6              1.2          <0. 1             0.1               1.9             18
                                     GBCR               0.7              2.8          <0. 1             0.1               3.6             17
                                     GBOB               3.2              10           <0. 1             0.2               14              64


                                     Tampa Bay


                                     TBOT               0.4              2.4          <0. 1             0.1               2.9             51
                                     TBKA               7.6              37           <0. 1             0.6               45              97
                                     TBPB               0.4              3.0          <0. 1             0.1               3.6             18
                                     TBNP               1.3              7.3          <0. 1             0.2               8.8             33
                                     TBCB               0.4              3.0          <0. 1             0.1               3.5             40
                                     TBMK               0.3              1.6          <0. 1             0.1               2.0             2.0


                                     aIncludes PCB congeners 77, 126, 169, 105, 118, 128 and 138.






                                                                                                            176


















                                                                                 0 PCBs 77,126,169
                                  300-
                                                                                 12 PCBs 105, 118
                                  250'                                           0 PCBs 128,138


                                  200



                                  150



                                  100



                                    50
                             el@            N
                             el@

                                     0
                                      GDSC GErYC GErM GBHR GBCR C33013   IMOT TBKA TBPB TBNP TBCB 7BMK
                                              Galveston Bay                        Tampa Day

                           Fig. 51. Toxic equivalents corresponding to three planar PCBs and selected mono-
                             and di-ortho chlorine-substituted congeners in oyster samples collected from six
                                            different locations in Galveston and Tampa Bays.
                                                          L d- L,_d








                                                                                                                   177




                         toxicity of the di-ortho congeners is a consequence of their much lower TCDD-like

                         activity rather than lower concentrations. As shown in Fig. 52, most of the toxicity

                         corresponding to planar PCBs is contributed by congener 126 while that corresponding to

                         mono-ortho derivative s is due to congener 118.

                             Although none of the other PCB congeners considered to be inducers of hepatic aryl

                         hydrocarbon hydroxylase (AHH) activity, i.e. congeners 123, 114, 158, 166, 167, 156,

                         157, 170 and 189), have been quantitated in Galveston and Tampa Bay oyster samples,

                         the concentration of most of them in commercial Aroclor mixtures are very low (Schulz et

                         al., 1989). With the exemption of congeners 123, 158 and 170, which range from the

                         minimum reporting level (<0.05%) to 0.81, 1.55 and 3.91%, respectively, in different

                         Aroclor mixtures, the contributions of the rest of the individual AHH-active congeners are

                         below 0.30%. Therefore, the contribution of these mono- and di-ortho AHH-active

                         PCBs to the total toxicity of environmental samples is expected to be negligible. For

                         example, congeners 77, 126, 169, 105 and 118 accounted for nearly 99% of the total

                         toxicity, calculated as the sum of the toxic equivalents of each individual AHH-active

                         congener, encountered in eggs (Smith et al., 1990). Thus, it can be speculated that the

                         total toxic equivalents reported for oyster samples collected in Galveston and Tampa Bays

                         (Table 15) would not increase by more than 10% of the total TEF values if all the AHH

                         active PCBs had been analyzed.



                         BUTYLTIN SPECIES



                            The decision to include butyltin compounds as pan of NOAA's NS&T Program was a

                         consequence of the increasing concern about the adverse effects of TBT to non-target

                         organisms. Thus, butyltin compounds have been monitored in Gulf of Mexico oyster

                         samples since 1986.















                                         Percentage




                             0      .........


                             Cr
                             C
                             M.
                             0=
                            0
                             0





                                 tz

                            E@
                            Co

                            0








                             0


                             0





                             0

                             C
                             Cr                     13


                             C







                                                                                                                     179




                             The use of TBT in antifouling paints in the U.S., on vessels under 25 m, was banned

                         in 1988 (U.S. EPA., 1987). In that year, the reported average concentration of TBT in
                         bivalves for U.S. coastal sites was 366 ng Sn g- I (Wade et al., 1988b). In general, the
                         body burden of the butyltin species was TBT>DBT>MBT. With a half-life of 34 days-1

                         in chronically contaminated oyster (see Chapter V), it would have taken about 240 days

                         (0.6 years) for the average concentrations encountered in Gulf of Mexico oysters of TBT
                         to be below the present detection limit (5 ng Sn g- 1) if all the inputs were stopped at that

                         time. Obviously, this is not a realistic estimation because the use of TBT was not

                         completely banned and because there might be a number of boats in use that had been

                         painted just before the ban. Also, TBT present in sediments, with a reported half-life of

                         more than 20 weeks, may be a long term source of TBT to the environment (Harris &

                         Cleary, 1987; Johnson et al., 1987; Maguire, 1986; Stang & Seligman, 1987; Unger et

                         al., 1987; Valkirs et al., 1986, 19 87 b).

                             Some changes can be seen, however, at some areas that have been followed since the

                         beginning of the Status and Trends Program. As mentioned before, it coincides with the

                         ban on the use of TBT-containing paints in U.S. waters. For example, Naples Bay,

                         Florida, has a very heavy recreational boating activity. At this site, a decreasing trend in

                         the total concentration of butyltins has been observed since 1988 (Fig. 53). A similar

                         decrease has been detected at Biloxi Bay, Mississippi. Under the actual input/degradation

                         conditions, it seems that a decrease of 50% in environmental TBT concentrations in these

                         and other areas similar to Naples and Biloxi Bays takes about 2-3 years. This is about an

                         order of magnitude larger than the time needed for oysters to depurate when transplanted

                         to a clean environment. At this rate, and assuming no environmental redistribution of

                         TBT, its concentrat ions in oysters from sites like Naples and Biloxi Bays should be below
                         the present detection limits (i.e. 5 ng Sn g-1) in 8 to 12 years. The much slower

                         decreases at sites with extensive recreational boating suggests that in spite of the













                                        200' . Naples Day (FL)                                            a TOT                 2000   Biloxi Day (FL)                                              a TOT
                                                                                                          0 DOT                                                                                     a DOT
                                                                                                          III MOT                                                                                   0 MOT
                                                                                                                                IS" -
                                  to                                                                                       to



                                        Hn                                                                                      1000




                                  C
                                  0     soll                                                                                      Soo
                                  U                                                                                        U





                                               1986      1987       1999      1989      1990      1991       1992                        1986      1987      1988       1989      1990       1991       1992
                                                                              Year                                                                                      Year

                                        20"                                                                                     2ooo-
                                             Galveston Bay (TX)                                           a  TOT                       Galveston Bay (TX)                                           III TOT
                                                                                                                                       Todd's Dump
                                             Yacht Club                                                   a  DOT                                                                                    0   DOT
                                                                                                                                                                                                    a   MDT
                                                                                                          0  MOT           rA   1500-
                                  V)    Moo-
                                  to                                                                                       to



                                        10"



                                                                                                                           C
                                                                                                                                  500-
                                        500
                                  U
                                                                                                                                    0                      M-A M.- 0
                                               1986      1997       1999      1999      1990      1991       1992                        1996      1997       1988      1989       1990      1991       1992
                                                                              Year                                                                                      Year
                                        Fig. 53. Total butiltin concentrations at selected sites in the Gulf of Mexico sampled between 1986 and 1992 as part of
                                                                                           NOAA's National Status and Trends Program.
                                                                                                                                                 M





                                                                                                                                                                                                                                 00








                                                                                                                181




                         restrictions applied in 1988 to the use of paints containing TBT a decreasing but still

                         significant amount of TBT is being introduced into the coastal marine environment. These

                         inputs may be from boats painted before 1988, TBT in sediments and/or TBT usage on

                         larger vessels. Other areas with important recreational boating activities but also heavy

                         maritime usages, like Galveston Bay, Texas, did not show any decrease and, even with

                         the actual restrictions to the TBT usage, no decreases in the near future may be found.








                                                                                                                  182











                                                               CHAPTERIX




                                                    SUMMARY AND PROSPEC77VES



                             Polynuclear aromatic hydrocarbons (PAHs), low molecular weight polychlorinated

                          biphenyls (PCBs), i.e. di-, tri- and tetrachlorobiphenyls, and tributyltin (TBT) were

                          rapidly bioaccumulated by oysters under environmental conditions. Apparent steady state

                          concentrations for these analytes were reached after 20 to 30 days of exposure. In

                          contrast, high molecular weight PCBs did not reached an equilibrium plateau at the end of

                          the seven week exposure period to relatively high PCB concentrations. However, the still

                          increasing concentrations encountered for these PCBs by the end of the exposure period

                          suggest that, given enough time, the equilibrium concentrations would eventually be

                          reached. When back-transplanted to their former location near Hanna Reef, originally

                          uncontaminated oysters depurated PAHs, low molecular weight PCB congeners and TBT

                          at similar rates while the heavier molecular weight PCB congeners were depurated at

                          considerably slower rates. In neither case, however, the original background

                          concentrations were reached after the 50-day depuration period.

                             Chronically contaminated Ship Channel oysters were also transplanted to the Hanna

                          Reef area during the second phase of the field experiment in Galveston Bay to allow for a

                          direct comparison with newly contaminated Hanna Reef individuals. In general, the

                          observed clearance, rates in Ship Channel oysters were slower than those exhibited by for

                          Hanna Reef bivalves. The differences might be explained as a consequence of different

                          distributions of PAH, PCB and TBT in the various body compartments in chronically








                                                                                                                   183




                         exposed oysters compared to recently contaminated individuals or a more effective

                         clearance response by originally uncontaminated oysters. A combination of both of these

                         processes should not be disregarded.

                             The present study presents evidence to substantiate the theory that the rates of uptake

                         and depuration of PCB congeners by the oyster Crassostrea virginica decreases as the

                         number of substituted chlorines in the two phenyl rings increases. However, in spite of

                         their lower uptake rates compared to low molecular weight congeners, the

                         pentachlorobiphenyls were the congeners bioaccumulated to the highest concentrations. It

                         was also observed that although heavier molecular weight congeners, i.e. heptachlorinated

                         biphenyls or higher, are more liphophilic, they have less favorable steric configurations,

                         which antagonistically affected their bioaccumulation and latter depuration by oysters.

                         Thus, bioconcentration and clearance of different PCB congeners appear to be more

                         affected by molecular size, e.g. molecular volume and cross-sectional area, which are

                         directly related to the number of chlorines substituted in the two phenyl rings and their

                         substitution patterns, rather than by hydro phobicity.

                             The influence of the chlorine substitution patterns in the bioaccumulation of PCBs by

                         oysters is particularly evident in the case of the highly toxic planar congeners, i.e. PCBs

                         77 and 126. Compared to other PCBs within the same level of chlorination, these planar

                         congeners take a longer time to equilibrate into and out of the organism's lipid pools.

                         Because of this, the importance of lipid content in oysters in determining potential

                         environmental hydrophobic organic accumulation might not be as significant as usually

                         speculated. Furthermore, the tendency for larger organic molecules to be less

                         concentrated in the lipidic pools of the organisms as a consequence of unfavorable steric

                         configurations suggests that these large molecules may also partition less easily into the

                         cells. Because of this low diffusivity among the different compartments in the organism,

                         it may take longer for the larger molecules to reach toxic concentrations.








                                                                                                                    184




                              The identification of the source of PCB congeners can also be confounded by the

                          differential PCB congeners uptake by oysters. Oysters exposed in the laboratory to a

                          wide molecular range of PCB congeners (1: 1: 1: 1 mixture of Aroclor 1242, 1248, 1254

                          and 1260), preferentially bioaccumulated congeners with four, five and six chlorines per

                          molecule resulting in a PCB profile similar to the distribution of homologs that would be

                          encountered in an approximately 2:1 mixture of commercial Aroclors 1248 and 1254.

                          Similar distribution of homologs has been observed in transplanted Hanna Reef oysters

                          during the field study near the Houston Ship Channel in Galveston Bay. Comparatively,

                          the profile of PCB homologs in indigenous Ship Channel oysters, exposed longer to the

                          the local levels, had a distribution profile with a slighly larger contribution of Aroclor

                          1254 (approximately 1: 1 Aroclor 1248 and 1254). Although it can be speculated that the

                          profile distributions encountered in chronically contaminated and newly exposed oysters

                          are the result of exposure to Aroclors 1248 and 1254 sources, it seems very probable that

                          the observed profiles are a consequence of the congener uptake discrimination from a

                          more complex mixture. However, it could also be that, even with a more complex

                          mixture of different Aroclors, there was a natural fractionation of the low, middle and

                          high molecular weight congeners. It is well known that a PCB mixture can not be

                          considered as a simple chemical contaminant but as a theoretical mixture of 209 congeners

                          with distinctive physico-chemical properties that can be environmentally fi-actionated. The

                          loss of the lowest and the highest molecular weight PCB congeners from a more complex

                          Aroclor mixture by evaporation/dissolution and adsorption/deposition, respectively, after

                          input can result in a profile distribution similar to that of Aroclor 1254 or a mixture of

                          Aroclors 1254 with 1248 or 1260. Therefore, it seems that, independently of the

                          composition of the. original PCB mixture, the environmental fractionation together with

                          preferential uptake will indicate Aroclor 1254 as the most probable contaminant source.

                          Incidentally, Aroclor 1254, which is one of the most commonly reported PCB mixtures as








                                                                                                                    185




                         the source in environmental pollution studies, is not the one that was produced in the

                         largest quantities. The most popular blend in the U.S. was Aroclor 1242, which

                         comprised over 50% of the total domestic production between 1957 and 1970 (Cairns et

                         aL, 198 6).

                            Similarly to what was observed for PCB congeners, oysters exposed in the laboratory

                         to a wide molecular range of PAHs showed the preferential uptake of four- and five-ring

                         PAHs. This observation was confirmed by the results obtained from the field
                         experiments in Galveston Bay. If oysters preferentially bioaccumulate combustion-

                         derived PAHs, i.e. four- and five-ring compounds, compared to petroleum-derived

                         PAHs, i.e. two- and three-ring compounds, then how accurate do they represent the

                         contamination at a site where most of the PAHs are petroleum-derived? This particular

                         area requires further attention.

                            Other areas requiring more investigation are the effect that simultaneous exposure to

                         PCBs and PAHs have on the concentrations encountered in environmentally contaminated

                         oysters and how well these concentrations correlate with local environmental levels.

                         During this study, it has been shown that oysters exposed in the laboratory to a mixture of

                         PCBs and PAHs, depurated PAHs at a faster rate when the contaminants input was

                         stopped than oysters that were not simultaneously exposed to PCBs. The half-lives for

                         individual PAHs encountered in oysters exposed in the laboratory to a mixture of PCBs

                         and PAHs compared more closely to those found during the field experiment in Galveston

                         Bay.

                            It can be concluded that indigenous oysters can be valuable bioindicators of

                         environmental contamination by trace organic compounds, particularly PAHs, PCBs and

                         TBT, gnly if their limitations are fully understood. Within these limitations, transplanted

                         oysters can be succesfully used to monitor environmental contamination by PAHs and

                         TBTs in areas lacking indigenous bivalves if deployed in-situ for a period of time of at



                                                                                                                  186         1
                                                                                                                              1
                          least 30 days; for PCBs, however, much longer time period, Le over 6 months, may be
                         required.                                                                                            I
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                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
                                                                                                                              I
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                                                                          TABLE A-1
                                             Biological Ancillary Parameters in Transplanted and Indigenous Oysters.


                                    Sample            Days after         Shell length         Wet weight           Lipids
                                                      u=splants              (cm)                 (g)               M


                                    Hanna    Reef-to-Ship Channel (HRSC)
                                    HRSC                    3              7.6+0.9              7.6+2.4            10+2.2
                                    HRSC                    7              7.5+0.8              7.9+3.1            10+3.4
                                    HRSC                  17               7.8+1.2               10+3.7            9.7+1.7
                                    HRSC                  30               7.3+0.5              8.3+1.9            11+4.0
                                    HRSC                  48               8.1+1.2               11+3.7            11+2.8


                                    Hanna    Reef-Ship    Channel-Hanna Reef (HRSCHR)
                                    HRSCHR                51               7.2+0.5              7.9+1.3            13+2.3
                                    HRSCHR                54               7.9+1.1               10+3.8            11+0.6
                                    HRSCHR                66               7.6+1.2              9.3+3.5            12+2.4
                                    1HRSCHR               78               7.4+0.8              9.6+3.6            11+0.8
                                    HRSCHR                98               7.7+1.0               13+3.9            12+2.5


                                    Ship Channel (SC)
                                    Sc                      3              7.4+1.3              7.3+1.6            14+3.6
                                    Sc                      7                       Sample was not collected
                                    SC                    17                 10+1.1              17+4.4            14+0.6
                                    Sc                    30               8.9+1.1               11+2.3            15+1.3
                                    Sc                    48               9.3+1.1               11+3.0            15+0.3


                                    Ship Channel-to-Hanna Reef (SCHR)
                                    SCHR                  51                 10+1.5              16+3.4            13+1.0
                                    SCHR                  54               8.7+1.1               13+3.0            13+1.4
                                    SCHR                  66               8.7+1.5               12+6.0            12+0.9
                                    SCHR                  78               8.4+1.2               11+4.1            12+1.3
                                    SCHR                  98               7.3+1.7               14+1.6            13+0.8
















                                                                                     TABLE A-2
                        Average PAH Concentrations      I S.D.) in Seawater, Sediment and Indigenous Ship Channel (SC) oyster Samples During the Uptake Phase
                                                of the Experiment at the Ship Channel Site and Estimated Bioconcentration Factors (BCF).


                                                                                                         Uptake phase (days)
                        Analyte                             Water        Sediment       0         3            7        17         30          48        BCFa
                                                             ng 1-1        ng g-I                                ng g-I

                        Naphthalene                         3.8ï¿½1.0        10ï¿½23        -       25ï¿½2.9         -      12+0.4      7.8ï¿½0-8     7.2ï¿½1.8      1,900
                        2-Methyinaphthalenc                 2.5ï¿½0.7        15ï¿½4.6       -       25ï¿½4.5         -      20ï¿½6.7      19ï¿½2.9      9.1ï¿½0.6      3,600
                        I-Methyinaphthalene                 1.9ï¿½0.6        7.8ï¿½1.4      -       13ï¿½3.1         -      13ï¿½4.0      9.1ï¿½2.1     3.8ï¿½0.8      2,0M
                        Biphenyl                            1.2ï¿½0.3        3.6ï¿½0.2      -       11ï¿½2.1         -      6.2ï¿½1.1     7.1ï¿½0.4     3.6ï¿½0.2      3,000
                        2,6-Dimethylnaphthaicnc             1.6ï¿½0.5        12ï¿½4.8       -       22ï¿½2.2         -      17ï¿½0.6      49ï¿½3.3      13ï¿½3.5       8,100
                        Acenaphthylene                      0.7ï¿½0.1        23ï¿½7.2               14ï¿½3.3         -      7.9ï¿½0.3     6.8ï¿½0.2     6.9ï¿½0.2      9,900
                        Acenaphthene                        0.6ï¿½0.1        9.5ï¿½3.0              21ï¿½2.6         -      13ï¿½1.0      31ï¿½1.3      5.8ï¿½0.4      9,700
                        2,3.5-Trimethyinaphthalene          2.4ï¿½0.6        32ï¿½5.3               53ï¿½9.1         -       83ï¿½14      120ï¿½6.3     56ï¿½6.2      23,000
                        Fluorene                            1.0ï¿½0.2        15ï¿½7.2               23ï¿½1.8         -      22ï¿½2.2      34ï¿½4.1      15ï¿½1.7      15,000
                        Phenanthrene                        2.2ï¿½0.7        51ï¿½5.8               45ï¿½3.6         -      39ï¿½2.7      110ï¿½12      23ï¿½2.9      10,000
                        Andvacene                           1.0ï¿½0.3        54ï¿½11                31ï¿½9.4         -      29ï¿½3.8      46ï¿½1.4      30ï¿½3.5      30,000
                        I-Methylphenanthrene                1.5ï¿½0.6        37ï¿½15                  63ï¿½12        -      110ï¿½2.8      88ï¿½13        89ï¿½11     59,000
                        Fluoranthene                        1.6ï¿½1.2        140ï¿½58       -       390ï¿½45         -      560ï¿½95      790ï¿½83      490ï¿½51     310,000
                        Pyrene                              2.1ï¿½1.6        190ï¿½38       -     1,200ï¿½130        -   1,400ï¿½270    1,400ï¿½59     1,900ï¿½80    900.000
                        Bcnz(a)anthracene                   0.8ï¿½0.1        110ï¿½42       -       130ï¿½25         -      160ï¿½18      220ï¿½13      280ï¿½13     350,000
                        Chrysene                            0.9ï¿½0.3        150ï¿½38       -       400ï¿½51         -      310ï¿½26      380ï¿½25      490ï¿½21     540,000
                        Benzo(b)fluoranthene                0.8ï¿½0.2        170ï¿½41               170ï¿½30         -      130ï¿½14      170ï¿½14      210ï¿½24     260,000















                                                                                     TABLE A-2
                                                                                      (confinued)



                                                                                                         Uptake phase (days)
                        Analyte                             Water       Sediment        0         3           7         17         30          48        BCFa
                                                            ng 1-1       ng g- I                                 ng g-I


                        Benzo(k)fluoranthene                0.3ï¿½0.1      140:1:38       -       52ï¿½15                48ï¿½2.8       66ï¿½7.2        82ï¿½14   270,000
                        Benzo(e)pyrene                      1.1ï¿½0.3      160ï¿½30         -       310ï¿½49        -      200ï¿½24       240ï¿½20      340ï¿½5.8   310.000
                        Benzo(a)pyrene                      0.8ï¿½0.1      142ï¿½45         -       57ï¿½16         -      73ï¿½7.1       97ï¿½11       160ï¿½6.3   200,000
                        Perylene                            1.1ï¿½0.3      110ï¿½18         -       110ï¿½25        -      110ï¿½11       140116      160ï¿½4.1   150,000
                        Indenot 1.2.3-c.d]pyrene            0.5ï¿½0.1        86ï¿½15                16ï¿½3.4               11ï¿½1.4       16ï¿½2.3      22ï¿½0.4     44,000
                        Dibenzo(a,b)anthracene              0.6ï¿½0.1      37ï¿½4.3         -       16ï¿½3.2        -      9.9ï¿½0.6      10ï¿½0.7      15ï¿½3.2     25,000
                        Benzo(g,h,i)peryiene                0.6ï¿½0.1        65ï¿½20        -       54ï¿½8.5        -      33ï¿½2.9       45D.7       6810.8    110,000


                        Total 2-Rings                       13ï¿½3.1       80ï¿½7.4         -       150ï¿½18        -      150ï¿½23       210ï¿½14      93ï¿½7.5       7,200
                        Total 3-Rings                       7.1ï¿½1.9      190ï¿½24         -       200ï¿½31        -      220ï¿½12       310ï¿½26      170ï¿½6.5    24,000
                        Total 4-Rings                       5.2ï¿½2.1      580ï¿½170        -    2,100ï¿½250        -   2,400ï¿½390     2,800ï¿½68   3,100ï¿½120    600,000
                        Total 5-Rings                       4.6ï¿½0.8      800ï¿½170        -      720ï¿½140        -      570ï¿½57       710ï¿½67      970ï¿½42    210,000
                        Total 6-Rings                       1.1ï¿½0.2      150ï¿½26         -       70ï¿½11         -      44ï¿½4.2       61ï¿½6.0      90ï¿½1.2     82,000


                        Total PAHs                          32ï¿½7.0     1,800ï¿½380        -    3,200ï¿½420        -  3.400ï¿½470 4,100ï¿½170       4.400ï¿½146    140,000


                        a Bioconcentration factor  concentrafion in transplanted oyster fissue at the end of the uptake pcriod/concentration in water.
















                                                                                                  TABLE A-3
                            Averap PAH Concentrations (i I S.D.) in Seawater, Sediment and Hanna Reef-to-Ship Channel (HRSC) Transplanted oyster Samples
                                        During the Uptake Phase of the Experiment at the Ship Channel Site and Estimated Bioconcentration Factors (BCF).


                                                                                                                          Uptake phase (days)
                          Analyte                                   Water          Sediment         0            3            7           17            30            48        BCFa
                                                                     ng 1-1         ng g- I                                        ng g-I

                          Naphthalene                               3.8ï¿½1.0         10ï¿½2.7        22ï¿½7.5      12ï¿½1.9      12ï¿½3.0         14ï¿½3.6      8.3ï¿½2.2          7.5ï¿½1.1     2,0M
                          2-Methyinaphthalene                       2.5ï¿½0.7         15ï¿½4.6        16ï¿½7.8      11ï¿½2.5      6.7ï¿½1.5        14ï¿½1.9       12ï¿½3.8          7.5ï¿½1.2     3,000
                          1 -Methylnaphthalene                      1.9ï¿½0.6         7.8ï¿½1.4       9.0ï¿½3.6    5.7ï¿½0.9      3.9ï¿½1.0        9.9ï¿½1.6     5.6ï¿½1.7          3.9ï¿½0.6     2,100
                          Biphenyl                                  1.2ï¿½0.3         3.6ï¿½0.2       8.3ï¿½3.2    7.2ï¿½1.8      5.6ï¿½1.6        6.8ï¿½2.2     6.8ï¿½1.6          4.3ï¿½0.5     3,600
                          2,6-Dimethylnaphthalcne                   1.6ï¿½0.5         12ï¿½4.8        15ï¿½3.2     9.8ï¿½0.9      6.8-f 1. 1     12ï¿½1.3       39ï¿½6.5          10ï¿½1.5      6,300
                          Acenaphthylcne                            0.7ï¿½0.1         23ï¿½7.2        7.3ï¿½2.1    7.4ï¿½1.5      6.5ï¿½1.8        6.7ï¿½1.5     6.1ï¿½1.2          6.5ï¿½1.7     93M
                          Acenaphthene                              0.6ï¿½0.1         9.5ï¿½3.0       4.0ï¿½1.7    9.2ï¿½0.8      9.5ï¿½1.1        9.1ï¿½1.6      25ï¿½6.6          7.6ï¿½1.3    13,000
                          2,3,5-Trimethylnaphthalene                2.4ï¿½0.6         32ï¿½5.3        26ï¿½5.9      22ï¿½4.9      14ï¿½3.3         50ï¿½11          90ï¿½20         38ï¿½11      16,000
                          Fluorene                                  1.0ï¿½0.2         15ï¿½7.2        9.3ï¿½1.5     11ï¿½1.2      11ï¿½1.4         16ï¿½2.3       26ï¿½5.9          16ï¿½3.1     16,000
                          Phenanthrene                              2.2ï¿½0.7         51ï¿½5.8        14ï¿½4.2      20ï¿½1.8      21ï¿½1.6         28ï¿½5.4         87ï¿½19         48ï¿½21      22,000
                          Anthracene                                1.0ï¿½0.3           54ï¿½11       16ï¿½1.6      11ï¿½1.6      12ï¿½3.1         20ï¿½4.1         36ï¿½11         30ï¿½6.7     30,000
                          1 -Methylphenanthmne                      1.5ï¿½0.6           37115       62ï¿½31       23ï¿½4.2      20ï¿½5.2         65ï¿½16          96ï¿½19         64ï¿½27      43,000
                          Fluoranthene                              1.6ï¿½1.2         140ï¿½58        11ï¿½2.5      110ï¿½18      130ï¿½19         410ï¿½45      620ï¿½110          490ï¿½76    310,000
                          Pyrene                                    2.1ï¿½1.6         190ï¿½38        16ï¿½3.5      300ï¿½44      340ï¿½50     1,000ï¿½100     1,300ï¿½190      1,900ï¿½190     900,000
                          Benz(Oanthracene                          0. 8ï¿½0. 1       110ï¿½42        8.3ï¿½5.0     22ï¿½3.3      30ï¿½4.9         140ï¿½17       180ï¿½26          260ï¿½27    330,000
                          Chrysene                                  0.9ï¿½0.3         150ï¿½38        7.7ï¿½3.5     71ï¿½9.5      110ï¿½16         250ï¿½20       320ï¿½38          450ï¿½49    500,000
                          Ben7o(b)fluoranthene                      0.8ï¿½0.2         170ï¿½41        3.0ï¿½1.0     28ï¿½4.9      39ï¿½3.7         100ï¿½2.7      140ï¿½14          220ï¿½20    280,000













                                                                                                               TABLE A-3
                                                                                                                  (wntinued)


                                                                                                                                         Uptake phase (days)                30             48          BCFa
                                Analyle                                          water        Sediment            0              3             7          -1 17
                                                                                 ng 1-1         ng 9-1                                                ng g
                                            lucranthene,                         0.3ï¿½0.1          140ï¿½38       3.3-+0.6          1 I:t 1. 1 14jo.9        41ï¿½4.3          50ï¿½9-1           86tl 1      290,000
                                Bcn7.0(k)j                                                        160DO        4.0:t 1 .0        4913.2     76-19.1      1500.2           210jJ4           330-t24     300,000
                                  Henzo(Opyrene                                  1.1ï¿½0.3                                                                   64ï¿½6.6          74ï¿½9-1          1 SOD i      190,WO
                                  Benzo(a)pyrene                                 0.9ï¿½0.1          142-145      6.1-15.0          M3.0        16ï¿½0-9       10019.6         1 OOV 3          150127       140'OM
                                 Perytcnc                                        1.1ï¿½0.3           110:H8      3.00-1            M2.9        27ï¿½2.4         1210.5         14:0-1          23-13.3       46,000
                                 Indenot 1.2.3-c.dlpyrene                        0.50. 1           g6:t , 5       j():j3.5       7.9f2.0    7.1+10-9                                       17ï¿½2.7         28,OM
                                 Dibenzo(a.b)anthraccne                          0.60.1            3714.3      3.0ï¿½2.6           6.7ï¿½1.9    5.6ï¿½0.5       9.7ï¿½1.6           11 ï¿½3.5
                                 Benzo(g,b,i)perylcne                            0.6ï¿½0.1            65:t2O     7.00.0            15ï¿½3.9      20ï¿½2.4         31ï¿½2.1         43ï¿½3.9          73ï¿½9.9        120,000
                                                                                 13ï¿½3.1             80ï¿½7.4        97ï¿½16          69ï¿½10       4913.8         110ï¿½15          160J:33          7)ï¿½12          5,500
                                  TOW 2-Rings                                    7.1ï¿½1.9            190ï¿½24        110ï¿½27         8 1 -t9- 5    80ï¿½14        150123          280ï¿½62         .170ï¿½43        24,OW
                                  Total 3-Rings                                  5.2ï¿½2.1          580ï¿½170         43ï¿½12          5OU69       610ï¿½97     1,8()O:t 180    2,400ï¿½340 3,100ï¿½290              600,000
                                  Total 4-Rings                                                   8OOï¿½i7O         30ï¿½9.0         1301'16      190ï¿½17        470ï¿½1 g         590ï¿½46 95()ï¿½110              210,000
                                  Total 5-Rings                                  4.6ï¿½0.9                                                              .9     44ï¿½2.4          58ï¿½43           96ï¿½13         97,OM
                                   ToW 6-Rings                                   1.1ï¿½0-2            15ft26        17ï¿½7.5         23ï¿½5.8       27+2
                                   Total PAH9                                     32ï¿½7.0 i,soo-1380               -290ï¿½4o        810ï¿½83    950ï¿½110 2,600t220            3,500ï¿½390 4,40W30                 138,000
                                   a Vloconcentration factor           concentration in transplanted oyster tiswe at the end of the Uptake Pcri(WcOncenvation in water-                                                              tj


                                                                                                                                                                                   ago
















                                                                                  TABLE A-4
                        Average PAH Concentrations (ï¿½ 1 S.D.) in Sediment and Ship Channel-to-Hanna Reef (SCHR) Transplanted Oyster Samples During the
                                        Deputation Phase of the Experiment at the Hanna Reef Site and Estimated Biological Half-Lives (BHL).


                                                                                                 Deputation phase (days)
                       Analyte                           Sediment           0           3          6          18         30           50         BHL(R2)a
                                                           ngg-I                                        ng g- I


                       Naphthalene                          3.9ï¿½0.3       7.2ï¿½1.8    8.5t].5     14ï¿½6.4      9.1ï¿½0.6    9.0ï¿½1.2      12ï¿½2.8
                       2-Methylnaphthalene                  5.6ï¿½0.3       9.1ï¿½0.6    11ï¿½1.9      9.7ï¿½1.2     6.1ï¿½1.3    6.5ï¿½1.5      11ï¿½2.4
                       I-Mclhyinaphthalenc                  4.1ï¿½0.4       3.8ï¿½0.8    5.5ï¿½0,8     6.0ï¿½1.4     3.9ï¿½0.7    5.3ï¿½1.6     7.8ï¿½1.0
                       Biphenyl                             4.3ï¿½0.9       3.6ï¿½0.2    6.0ï¿½1.1     5.9ï¿½0.7     5.6ï¿½1.3    5.7ï¿½0.6     7.1ï¿½1.5
                       2,6-Dimcthyinaphthalenc              6.1ï¿½2.0       13ï¿½3.5     17ï¿½4.9      10ï¿½1.2      3.8ï¿½1.0    7.9ï¿½1.0     6.2ï¿½2.4
                       Acenaphthylene                       4.8ï¿½0.4       6.9ï¿½0.2    5.1ï¿½2.6     3.1ï¿½3.3     3.7ï¿½2.7    3.8ï¿½2.0     3.1ï¿½1.2
                       Acenaphthene                         2.9ï¿½0.4       5.8ï¿½0.4    4.2ï¿½0.9     3.1ï¿½0.9     2.2ï¿½0.7    14ï¿½2.1      3.3ï¿½1.0
                       2,3,5-Trimethyinaphthalene           5.6ï¿½0.9       56ï¿½6.2     44ï¿½10       23ï¿½6.8      17ï¿½5.4     16ï¿½2.8      9.1ï¿½2.6      22(0.83)
                       Fluorene                             4.9ï¿½0.8       15ï¿½1.7     14ï¿½1.4      11ï¿½2.5      5.7ï¿½1.0    15ï¿½2.1      7.5ï¿½2.8
                       Phenanthrene                          12ï¿½3.4       23ï¿½2.9     24ï¿½3.9      18ï¿½1.1      15ï¿½2.9     46ï¿½4.6       29ï¿½8.8
                       Anthracene                           7.6ï¿½1.0       30ï¿½3.5     19ï¿½7.0      16ï¿½4.2      13ï¿½3.6     16ï¿½4.4      9.5ï¿½2.8      42(0.68)
                       I-Methylphenanthrene                 4.8ï¿½2.4       89ï¿½11      66ï¿½16       54ï¿½17       47ï¿½15      36ï¿½6.5       18ï¿½5.4      24(0.96)
                       Fluoranthene                          29ï¿½8.4       490ï¿½51     350ï¿½89      250ï¿½45    260ï¿½110      320ï¿½18       110ï¿½29      32(0.69)
                       Pyrene                                29ï¿½7.7     1,900ï¿½80  1,300ï¿½290      870ï¿½230   500ï¿½140      300ï¿½37       95ï¿½28       12(0.98)
                       Benz(a)anthracene                     18ï¿½4.2       280ï¿½13     200ï¿½48      170ï¿½44      110ï¿½32     59ï¿½9.4       26ï¿½7.2      15(0.99)
                       Chrysene                              15ï¿½2.8       490ï¿½21     380ï¿½53      340ï¿½48      230ï¿½52     110ï¿½18       54ï¿½10       16(0.99)
                       Benzo(b)fluoranthenc                  17ï¿½3.0       210ï¿½24     200ï¿½34      200ï¿½9.5     140116     59ï¿½11        18ï¿½5.6
















                                                                                      TABLE A-4
                                                                                       (continued)




                                                                                                   Depuration phase (days)
                        Anw@                                Sediment            0           3           6          18          30           50           BtIL(R2)a
                                                             ngg-I                                           ng g-l


                        Benzo(k)fluoranthene,                   131l.7         82ï¿½14      71ï¿½12       72ï¿½8.8      35ï¿½2.4      17ï¿½3.9        5.5ï¿½2.7
                        Benzo(e)pyrene                          17ï¿½2.8       340ï¿½5.8      310ï¿½16     300ï¿½6.9      210ï¿½20      89ï¿½21         44ï¿½8.7      16(0.98)
                        Benzo(a)pyrene                          15:1. 1. 2   160ï¿½6.3      110ï¿½22      79ï¿½17       39ï¿½8.7      14ï¿½2.2        4.4ï¿½1.3     10(0.99)
                        Perylene                                74ï¿½6.3       IW4.1        130118      120ï¿½23      71ï¿½18       28ï¿½6.6        11ï¿½3.8      13(0.99)
                        Indenol 1,2,3-c,d]pyrene                15ï¿½3.8       22ï¿½0.4       23ï¿½7.2      22ï¿½1.2      14ï¿½6.2      2.3ï¿½1.3       1.2ï¿½0.2     11 (0.93)
                        Dibenzo(a,h)anffiracene                 4.9ï¿½0.9      15ï¿½3.2       17ï¿½7.5      18ï¿½4.3      15ï¿½6.1      3.3ï¿½0.8       1.7ï¿½0.6     14(0.90)
                        Benzo(g,h,i)perylene                    14ï¿½3.5       68ï¿½0.8       70ï¿½18       73ï¿½6.1      37ï¿½7.2      13ï¿½0.4        4.8ï¿½1.7     12(0.98)


                        Total 2-Rings                           30ï¿½3.8       93ï¿½7.5       92ï¿½18       68ï¿½4.9      45ï¿½3.8      50ï¿½4.4        53ï¿½13
                        Total 3-Rings                           37ï¿½3.6       170ï¿½6.5      130:01      110ï¿½26      87ï¿½23       130ï¿½16        70ï¿½22
                        Total 4-Rings                           90ï¿½22     3,100ï¿½120   2.200ï¿½450   1,600ï¿½360    1.100ï¿½310      780ï¿½76        290ï¿½74
                        Total 5-Rings                           140ï¿½9.4      970ï¿½42       850ï¿½48      790ï¿½56      510ï¿½43      210ï¿½40        85ï¿½23
                        Total 6-Rings                           30ï¿½6.9       90ï¿½1.2       93ï¿½25       95ï¿½7.2      50ï¿½13       15ï¿½1.0        6.0ï¿½1.9


                        Total PAHs                              330ï¿½32    4,400ï¿½150  3.400ï¿½440 2,700ï¿½430       1,800ï¿½330    1200ï¿½120      500ï¿½130


                        a R2 = square of correlation coefficient for regression equation.















                                                                                         TABLE A-5
                         Average PAH Concentrations       I S.D.) in Sediment and Hanna Roet-Ship Cbannel-Hanna Reef (14RSCHR) Transplanted Oyster Samples
                                     During the Depuration Phase of the Experiment at the Hanna Reef Site and Esdmated Biological Half-Lives (BHL).


                                                                                                  Depuration phase (days)
                        Analyte                            Sediment             0           3          6           18          30           50          BtIL(R2)a
                                                             ngg-I                                           ng g-l


                        Naphthalene                           3.9ï¿½0.3        7.5ï¿½1.1     7.5ï¿½0.5     9.3:LI.4    6.6ï¿½0.8      8.3ï¿½1.1      13ï¿½5.6
                        2-Methylnaphthalene                   5.6ï¿½0.3        7.5ï¿½1.2     12ï¿½1.9      11ï¿½3.1      5.3ï¿½0.8      6.0ï¿½0.3      11ï¿½0.6
                        I-Methyinaphihalene                   4. 110. 4      3.9ï¿½0.6     6.0ï¿½0.7     5.6ï¿½2.)     2.8ï¿½0.4      4.0ï¿½0.6    6.811.2
                        Biphenyl                              4.3ï¿½0.9        4.3ï¿½0.5     5.0ï¿½0.3     4.7ï¿½1.0     4.8ï¿½1.0      6.4ï¿½1.1    7.7ï¿½1.9
                        2,6-Dimethyinaphthalene               6.1ï¿½2.0        10ï¿½1.5      19ï¿½0.8      7.3ï¿½0.6     3.6ï¿½1.1      7.9ï¿½1.8    6.4ï¿½2.0
                        Acenaphthylcne                        4.8ï¿½0.4        6.5ï¿½1.7     6.3ï¿½1.7     3.9ï¿½1.2     3.2ï¿½1.2      3.5ï¿½1.5    3.6ï¿½1.4
                        Accnaphlbene                          2.9ï¿½0.4        7.6ï¿½1.3     5.0ï¿½0.4     2.7ï¿½0.4     2.0ï¿½0.3      13ï¿½3.0     3.4ï¿½0.7
                        2,3,5-Trimethyinaphthalene            5.6ï¿½0.9        38ï¿½11       41ï¿½9.2      15ï¿½4.2      16ï¿½6.5       12ï¿½0.9     8.2ï¿½0.6        24(0.74)
                        Fluorene                              4.9ï¿½0.8        16ï¿½3.1      15ï¿½1.4      9.0ï¿½1.7     5.1ï¿½0.5      13ï¿½2.0     8.1ï¿½1.9
                        Phenanthrene                           12ï¿½3.4        48ï¿½21       33ï¿½2.8      15ï¿½2.2      12ï¿½1.6       "ï¿½l 1        24ï¿½2.8
                        Andiracene                            7.6ï¿½1.0        30ï¿½6.7      26ï¿½4.8      15ï¿½2.8      17ï¿½4.9       11ï¿½2.2     5.8ï¿½2.4        24(0.90)
                        1-Methylphenandurne                   4.8ï¿½2.4        64ï¿½27       46ï¿½8.4      47ï¿½4.5      29ï¿½10        26ï¿½4.0       12ï¿½2.4       23(0.97)
                        Fluoranthene                           29ï¿½8.4        490ï¿½76      350ï¿½7.4     160ï¿½42      190ï¿½35       220ï¿½43       80ï¿½20        26(0.67)
                        Pyrene                                 29ï¿½7.7    1,900ï¿½190       1.400ï¿½86   570ï¿½170     350ï¿½100       170ï¿½41       56ï¿½10        10(0.95)
                        Benz(a)anthracene                      18ï¿½4.2        260ï¿½27      250ï¿½22      150ï¿½47      70ï¿½25        39ï¿½5.4       20ï¿½1.7       13(0.96)
                        Chrysene                               15ï¿½2.8        450ï¿½49      420ï¿½15      280ï¿½69      150ï¿½35       58ï¿½11        30ï¿½4.7       12(0.99)
                        Benzo(b)fluoranthene                   17ï¿½3.0        220ï¿½20      200ï¿½9.5     210ï¿½16      76ï¿½6.3       25ï¿½8.7       15ï¿½4.2       12(0.95)

















                                                                                       TABLE A-5
                                                                                          (confinued)



                                                                                                   Dcpuration phase (days)
                        Analyte                            Sediment             0            3          6           18          30            50          BHL(R2)a
                                                             ng 9-1                                           ng g- I


                        Benzo(k)fluoranthene                    13ï¿½1.7        86ï¿½11       76:L8.1     78ï¿½5.4       19ï¿½4.2      6.8ï¿½2.0      4.4ï¿½1.6        10(0.96)
                        Benzo(e)pyrene                          17ï¿½2.8        330ï¿½24      310ï¿½21      280ï¿½19       110ï¿½26      39ï¿½12        21ï¿½43          12(0.97)
                        Benzo(a)pyrene                          MA.2          150ï¿½31      130ï¿½25       81ï¿½19       32ï¿½3.8      8.6ï¿½2.7      3.5ï¿½1.9          9(0.99)
                        Perylene                                74ï¿½6.3        150ï¿½27      140117      100ï¿½19       28ï¿½8.1      13ï¿½2.1       7.5ï¿½1.1        11 (0.94)
                        Indenol 1,2.3-cdipyrene                 15ï¿½3.8        23ï¿½3.3      18ï¿½3.1      16ï¿½2.6       8.4ï¿½1.8     1.8ï¿½0.9      1.0ï¿½1.1        10(0.96)
                        Dibenzo(a,h)anthracene                  4.9ï¿½0.9       17ï¿½2.7      15ï¿½1.9      13ï¿½2.8       7.9ï¿½2.8     2.3ï¿½1.2      2.3ï¿½1.7        16(0.93)
                        Benzo(g,h,i)peryiene                    14ï¿½3.5        73ï¿½9.9      61ï¿½1.2      51ï¿½3.3       17ï¿½3.6      7.7ï¿½1.1      4.1ï¿½1.6        11(0.96)


                        Total 2-Rings                           30ï¿½3.8        71ï¿½12       90ï¿½12       53ï¿½4.8       39ï¿½6.1      45ï¿½0.4       52ï¿½7.4
                        Total 3-Rings                           37ï¿½3.6        170ï¿½43      130ï¿½15      92ï¿½63        68ï¿½16       110ï¿½9.4      57ï¿½6.6
                        Total 4-Rings                           90ï¿½22     3.100ï¿½290     2,400ï¿½96   1,200ï¿½320     750ï¿½180       490ï¿½97       190ï¿½20
                        Total 5-Rings                           140ï¿½9.4     950ï¿½110       870ï¿½73      750ï¿½22       270ï¿½17      95ï¿½24          54ï¿½13
                        Total 6-Rings                           30ï¿½6.9        93ï¿½13       79ï¿½4.0      67ï¿½33        26ï¿½4.2      9.5ï¿½1.4      5.1ï¿½2.4


                        Total PAHs                              330ï¿½32    4,400ï¿½330   3,600ï¿½170 2,100ï¿½320       1.200ï¿½190     750ï¿½120       360ï¿½18


                        a R2 = square of correlation coefficient for regression equation.


                                                                                                                                                                                  00
















                                                                                  TABLE A-6
                         Average PCB Congener Concentrations (ï¿½ I S.D.) in Seawater. Sediment and Ship Channel (SC) Indigenous Oyster Samples During the
                                        Uptake Phase of the Experiment at the Ship Channel Site and Estimated Bioconcentration Factors (BCF).


                                                                                                     Uptake phase (days)
                       Analyte                           Water       Sediment       0          3         7          17         30          48      BCFa
                                                          ng 1-1       ng g-I                                ng g-l

                       18                             0.05ï¿½0.03                            3.0ï¿½0.7               4.7ï¿½0.3     6.8ï¿½2.1    6.1ï¿½0.6    120,000
                       15/17                          0.03ï¿½0.02      0.16ï¿½0.11             3.1ï¿½0.9               4.2ï¿½0.3     5.6ï¿½1.8    4.8ï¿½0.5    160,000
                       26                                                                   35ï¿½5.3                34ï¿½2.0      30ï¿½5.9     36ï¿½8.0
                       50/31                                         0.15ï¿½0.07             2.5ï¿½0.4               3.4ï¿½0.2     4.3ï¿½1.4    5.2ï¿½0.8
                       28                                                                  6.5ï¿½1.1               7.1ï¿½0.6     6.7ï¿½1.4    8.0ï¿½1.4
                       52                             0.50ï¿½0.29      1.58ï¿½0.17              62ï¿½7.0                55ï¿½6.1      47ï¿½11      52ï¿½4.0    100,000
                       49                             0.14ï¿½0.09      0.65ï¿½0.17              36ï¿½2.2                31ï¿½4.5      29ï¿½3.8     31ï¿½3.2    220,000
                       47/48/75                                                             25ï¿½1.1                20ï¿½0.9      16ï¿½5.7     19ï¿½2.0
                       44                             0.20ï¿½0.22      0.56ï¿½0.19              27ï¿½1.1                21ï¿½1.6      19ï¿½3.9     20ï¿½3.2    100,000
                       37/42/59                       0.09ï¿½0.09      0.21ï¿½0.06              26ï¿½0.8                28ï¿½3.0      21ï¿½3.6     33ï¿½5.3    370,0M
                       41                                            0.44ï¿½0.09              21ï¿½4.6                17ï¿½4.7      15ï¿½2.3     16ï¿½2.8
                       40                                            0.14ï¿½0.02             9.7ï¿½0.4                10ï¿½0.3      10ï¿½1.2     13ï¿½0.5
                       74                             0.07ï¿½0.03      0.23ï¿½0.07              17ï¿½0.9                13ï¿½3.2      12ï¿½0.9     15ï¿½0.9    210,000
                       70                             0.05ï¿½0.03      0.87ï¿½0.41              46ï¿½2.5                34ï¿½0.9      32ï¿½0.4     38ï¿½2.0    760,000
                       95                                                                   95ï¿½9.0                71ï¿½0.8      56ï¿½12      63ï¿½8.2
                       91                             0.07ï¿½0.04      0.40ï¿½0.14              27ï¿½2.6                20ï¿½2.7      15ï¿½4.9     22ï¿½1.0    310,000
                       60/56                                                                10ï¿½0.8               8.2ï¿½1.1     8.9ï¿½1.5    9.5ï¿½1.4
                       92                                            0.45ï¿½0.21              31ï¿½7.2                32ï¿½5.8      18ï¿½5.7     26ï¿½6.6
















                                                                                    TABLE A-6
                                                                                     (continued)



                                                                                                       Uptake phase (days)
                      Analyte                             Water       Sediment        0          3          7         17          30          48       BCFa
                                                           ng 1-1       ng g-I                                 ng 9-1


                      84                                              0.71ï¿½0.23                46ï¿½0.8                35ï¿½4.9      27ï¿½7.9      29ï¿½7.3
                      101)90                           0.27ï¿½0.12      2.19ï¿½0.65                110ï¿½13                85ï¿½2.2      67ï¿½8.1      71ï¿½8.5    260,000
                      99                               0.14ï¿½0.08      1.44ï¿½0.09                62ï¿½5.5                52ï¿½1.1      41ï¿½4.9      45ï¿½4.6    320.000
                      97                                              0.68ï¿½0.26                33ï¿½3.0                26ï¿½1.4      20ï¿½2.1      20ï¿½3.7
                      87/11                                           1.33ï¿½0.40                53ï¿½4.9                40ï¿½1.4      30ï¿½3.6      32ï¿½3.1
                      1 10fl7                          0.24ï¿½0.08      3.84ï¿½1.00                130ï¿½12               110ï¿½6.8      76ï¿½15       80ï¿½12     330,0(X)
                      82                                              0.30ï¿½0.06                14ï¿½1.3               9.2ï¿½0.8     7.7ï¿½1.0      6.3ï¿½2.3
                      151                              0.08ï¿½0.05      0.22ï¿½0.04                16ï¿½1.1                13ï¿½0.8     9.1ï¿½2.1      10ï¿½2.2    130.000
                      135                              0.10ï¿½0.02      0.16ï¿½0.02                14ï¿½5.0                10ï¿½1.8     7.4ï¿½1.9      8.7ï¿½2.1   87,000
                      107                                                                      15ï¿½1.9                13ï¿½2.8      12ï¿½0.2      15ï¿½3.1
                      149/123                          0.19ï¿½0.12      0.90ï¿½0.23                44ï¿½4.5                36ï¿½2.4      31ï¿½1.9      36ï¿½3.5    190,000
                      118                              0.12ï¿½0.04      1.35ï¿½0.37                88ï¿½12                 68ï¿½5.6      51ï¿½8.3      56ï¿½6.3    470,000
                      146                                             0.13ï¿½0.05                13ï¿½3.4                10ï¿½0.9     8.0ï¿½1.1      7.8ï¿½2.1
                      1531132                          0.59ï¿½0.32      2.15ï¿½0.54                170ï¿½11                110ï¿½19      93ï¿½10       100ï¿½10    170,000
                      105                              0.12ï¿½0.06      0.67ï¿½0.16                30ï¿½7.8                23ï¿½5.2      15ï¿½3.5      17ï¿½6.1    140,000
                      141/179                          0.12ï¿½0.11      0.34ï¿½0.03               7.3ï¿½1.7               4.5ï¿½0.5     3.7ï¿½1.0      5.2ï¿½0.9   43,000
                      138/160                          0.59ï¿½0.17      2.52ï¿½0.12                77ï¿½12                 60ï¿½5.5      44ï¿½7.3      47ï¿½10     80,000
                      187                              0.14ï¿½0.09      0.11ï¿½0.04                18ï¿½6.9                15ï¿½2.4      13ï¿½1.3      15ï¿½2.5    110,000
















                                                                                        TABLE A-6
                                                                                         (continued)




                                                                                                             Uptake phase (days)
                         Analyte                              Water       Sediment        0           3           7          17           30          48       BCFa
                                                              ng 1-1        ngg-I                                    ng g-l


                         128                               0.0810.06      0.42ï¿½0.09                 10ï¿½0.6                7.7ï¿½1.3      6.3ï¿½0.1     5.9ï¿½1.0
                         177                               0-05ï¿½0.04      0.18ï¿½0.06                5.3ï¿½0.2                4.3ï¿½0.9      3.7ï¿½0.2     4.6ï¿½0.1     92,000*
                         180                               0.33ï¿½0.18      0.40ï¿½0.06                6.5ï¿½0.6                 5.5:EO.9    4.1ï¿½0.5     4.6ï¿½0.2     14,000




                         Total dichlorobiphenyls                                                                                            1.5
                         Total trichlorobiphenyis          0.13ï¿½0.08      0.31ï¿½0.17                      59                    64           64          71     540,000
                         Total tetrachlorobiphenyls        1.00ï¿½0.56      6.16ï¿½1.58                     270                    240          210         250    250,000
                         Total pentachlorobiphenyls        0.99ï¿½0.38      13.5ï¿½3.49                     740                    580          440         490    490,000
                         Total hexachlorobiphenyls         1.64ï¿½0.81      6.98ï¿½1.13                     360                    250          210         230    140,000
                         Total heptachlorobiphenyls        0.78ï¿½0.50      1.14ï¿½0.12                      57                    46           40          52     67,000
                         Total octachlorobiphenyis         0.09ï¿½0.05      0.25ï¿½0.03                      1.6                   1.3          0.5         1.9    21,000
                         Total nonachlorobiphenyis                                                       1.0                   0.7          0.5         0.8
                         Total decachlorobiphenyl                                                       0.2                    0.6          0.4         0.4


                         Total PCBs                        4.62ï¿½2.15      28.4ï¿½6.41                    1500                   1200          960        1100    240,000


                         a Bioconcentration factor = concentration in transplanted oyster tissue at the end of the uptake period/concentration in water.
















                                                                                       TABLE A-I
                         Average PCB Congener Concentrations (ï¿½ I S.D.) in Seawater, Sediment and Hanna Reef-to-Ship Channel (HRSQ Transplanted Oyster
                               Sarnple@ During the Uptake Phase of the Experiment at the Ship Channel Site and Estimated Bioconccntration Factors (13CF).


                                                                                                            Uptake phase (days)
                        Analyte                              Water        Sediment        0           3          7          17         30          48          BCFa
                                                              ng 1-1        ng g-                                     ng g-I


                        18                                0.05ï¿½0.03                                1.6ï¿½0.4    2.2ï¿½0.3    3.7ï¿½1.0     4.4ï¿½0.7    6.0ï¿½1.0     120,000
                        15/17                             0.03ï¿½0.02       0.16ï¿½0.11                1.2ï¿½0.5     11ï¿½2.7    2.9ï¿½0.8     3.0ï¿½1.2    4.5ï¿½1.3     150,000
                        26                                                                         6.5ï¿½1.2     11ï¿½2.8      19ï¿½2.5     23ï¿½2.1      30ï¿½9.3
                        50/31                                             0.15ï¿½0.07                1.0ï¿½0.3    3.8ï¿½2.1    2.7ï¿½0.9     5.2ï¿½2.8    9.8ï¿½4.6
                        28                                                                         2.4ï¿½0.2    3.8ï¿½1.1    5.6ï¿½0.7     7.9ï¿½1.3    9.9ï¿½1.4
                        52                                0.50ï¿½0.29       1.58ï¿½0.17                 17ï¿½2.9     28ï¿½2.1      32ï¿½2.3     37ï¿½3.7      51ï¿½5.4    100,000
                        49                                0.14ï¿½0.09       0.65ï¿½0.17                6.6ï¿½0.7     13ï¿½1.6      16ï¿½1.0     22ï¿½1.5      291:1.5   210,000
                        47/48175                                                                   5.6ï¿½1.6    9.6ï¿½1.1      11ï¿½1.3     14ï¿½1.3      18:L2.2
                        44                                0.20ï¿½0.22       0.56ï¿½0.19                6.9ï¿½0.7     14ï¿½2.0      14ï¿½1.3     17ï¿½1.9      22ï¿½2.3    110,000
                        37/42/                            0.09ï¿½0.09       0.21ï¿½0.06                 12:LO.7    17ï¿½3.3      19ï¿½1.9     22ï¿½1.6      42ï¿½8.3    470,000
                        41                                                0.44ï¿½0.09                4.3ï¿½0.8    8.0ï¿½0.1    8.9ï¿½3.3      12ï¿½2.1      20ï¿½1.4
                        40                                                0.14ï¿½0.02                1.4ï¿½0.5    4.6ï¿½1.4    6.7ï¿½0.7     9.4ï¿½0.9      14ï¿½2.5
                        74                                0.07ï¿½0.03       0.23ï¿½0.07                2.9ï¿½0.5    5.2ï¿½0.5    7.3ï¿½0.9     9.4ï¿½2.1      13ï¿½2.7    190,000
                        70                                0.05ï¿½0.03       0.87ï¿½0.41                4.7ï¿½1.2    9.7ï¿½1.9      15ï¿½1.6     23ï¿½3.5      31ï¿½2.8    620,000
                        95                                                                          11ï¿½1.2     22ï¿½2.1      29ï¿½1.2     41ï¿½5.5      55ï¿½5.3
                        91                                0.07ï¿½0.04       0.40ï¿½0.14                4.2ï¿½0.5    9.1ï¿½1.1      11ï¿½0.9     14ï¿½2.0      24ï¿½8.6    340.000
                        60/56                                                                      2.2ï¿½0.5    3.5ï¿½0.6    5.4ï¿½0.8     7.3ï¿½1.4      10ï¿½1.9
                        92                                                0.45ï¿½0.21                4.8ï¿½1.3    6.5ï¿½1.1      11ï¿½2.5     15ï¿½1.0      22ï¿½8.0
















                                                                                        TABLE A-7
                                                                                          (continued)



                                                                                                              Uptake phase (days)
                         Analyte                              Water        Sediment        0           3           7          17         30          48         BCFa
                                                               ng 1-1        ng g-I                                    ng g-I


                         84                                                0.71ï¿½0.23                5.9ï¿½0.5     13ï¿½2.2      17ï¿½1.5      24ï¿½3.8      29ï¿½0.9
                         101/90                            0.27ï¿½0.12       2.19ï¿½0.65                 11ï¿½1.6     20ï¿½4.1      27ï¿½1.1      37ï¿½4.3      43ï¿½5.2    160,000
                         99                                0. 14:LO.09     1.44ï¿½0.09                8.7ï¿½1.0     15ï¿½1.6      18ï¿½3.3      27ï¿½2.9      29ï¿½1.3    210.000
                         97                                                0.68ï¿½0.26                3.9ï¿½1.6     6.8ï¿½1.1    8.9ï¿½1.7      11ï¿½1.8      14ï¿½3.2
                         87/115                                            1.33ï¿½0.40                4.7ï¿½0.6     8.6ï¿½1.3     13ï¿½0.6      16ï¿½2.0      20ï¿½1.4
                         1 IOM                             0.24ï¿½0.08       3.84ï¿½1.00                 13ï¿½1.8     28ï¿½4.2      37ï¿½1.7      50ï¿½5.2      61ï¿½4.2    250,000
                         82                                                0.30ï¿½0.06                1.8ï¿½0.5     3.2ï¿½0.4    3.3ï¿½0.7     4.4ï¿½0.1    5.9ï¿½1.0
                         151                               0-08ï¿½0-05       0.22ï¿½0.04                1.7ï¿½0.5     2.6ï¿½0.9    4.0ï¿½0.8     4.9ï¿½0.6    6.0ï¿½1.0       75,000
                         135                               0.10ï¿½0.02       0.16ï¿½0.02                2.6ï¿½1.4     2.2ï¿½0.7    3.6ï¿½0.9     4.0ï¿½0.6    5.0ï¿½0.5       50,000
                         107                                                                        1.3ï¿½0.3     2.4ï¿½0.7    3.6ï¿½0.6     5.3ï¿½1.1    6.6ï¿½1.0
                         149/123                           0.19ï¿½0.12       0.90ï¿½0.23                4.7ï¿½0.4     7.8ï¿½1.1     11ï¿½0.4      14ï¿½1.5      18ï¿½1.6      95,000
                         118                               0.12ï¿½0.04       1.35ï¿½0.37                7.6ï¿½1.4     14ï¿½1.6      21ï¿½1.4      29ï¿½2.0      34ï¿½2.5    280,000
                         146                                               0.13ï¿½0.05                3.4ï¿½0.5     4.2ï¿½1.9    3.6ï¿½0.6     4.0ï¿½0.6    4.1ï¿½1.1
                         153/132                           0.59ï¿½0.32       2.15ï¿½0.54                 16ï¿½4.9     18ï¿½6.3      28ï¿½4.8      38ï¿½7.5       64ï¿½12    110,000
                         105                               0.12ï¿½0.06       0.67ï¿½0.16                7.6ï¿½2.7     11ï¿½1.1      13ï¿½2.0      13ï¿½1.4      14ï¿½3.0    120,000
                         141/179                           0.12ï¿½0.11       0.34ï¿½0.03                1.7ï¿½0.6     1.6ï¿½0.5    2.3ï¿½1.0     3.3ï¿½0.7    4.7ï¿½0.5       39,000
                         138/160                           0.59ï¿½0.17       2.52ï¿½0.12                 12ï¿½2.0     17ï¿½2.7      20ï¿½0.7      27ï¿½5.2      27ï¿½4.7      46,000
                         187                               0.14ï¿½0.09       0.11ï¿½0.04                4.3ï¿½0.4     3.4ï¿½1.3    5.9ï¿½1.7     6.4ï¿½1.1      11ï¿½2.2      78,000
















                                                                                               TABLE A-7
                                                                                                (continued)



                                                                                                                     Uptake phase (days)
                          Analyte                                 Water         Sediment         0            3            7          17           30          48          BCFa
                                                                   ng 1-1         ng g- I                                      ng g-l

                          128                                                   0.42ï¿½0.09                  1.7ï¿½0.3     2.5ï¿½0.3 2.9ï¿½0.4          3.8:10.6     3.9ï¿½0.6
                          177                                   0.05ï¿½0.04       0.18ï¿½0.06                  1.0ï¿½0.2     1.3ï¿½0.5      1.6ï¿½0.8     1.7ï¿½0.1      3.5ï¿½1.6       70,000
                          180                                   0.33.+0.18      0.40ï¿½0.06                  1.5ï¿½0.3     2.4ï¿½0.5      2.3ï¿½03      3.4ï¿½0.7      3.8ï¿½ f.7      12,000


                          Total dichlorobiplicnyls                                                         0.1ï¿½0.1                              0.3ï¿½0.6      0.1ï¿½0.2
                          Total trichlorobiphcnyis               0.130.08         0.310.17                 16ï¿½2.5      31ï¿½5.5       46ï¿½6.5      50ï¿½6.2       66ï¿½9.3      500,000
                          Total tetrachlorobiphenyis             1.000.56         6.161.58                   58ï¿½13     110ï¿½9.2      130ï¿½7.6     170ï¿½19       240ï¿½24      240,000
                          Total pentachlorobiphenyls             0.990.38         13.53.49                 84ï¿½7.6      160ï¿½17       210ï¿½9.2     290ï¿½15       360ï¿½26      360,000
                          Total hexachlorobiphenyis              1.640.81         6.981.13                 44ï¿½1.9        58ï¿½12      77ï¿½6.5      100ï¿½17       120ï¿½42        74,000
                          Total heptachlorobiphenyis             0.780.50         1.140.12                 17ï¿½3.8      20ï¿½7.6         27ï¿½10     31ï¿½9.9         45ï¿½25       58,000
                          Total octachlorobiphenyls              0.090.05         0.250.03                 0.9ï¿½0.9     1.5ï¿½1.2      1.1ï¿½0.5     1.1ï¿½0.9      1.3ï¿½0.9       14,000
                          Total nonschlorobiphenyls                                                        0.3ï¿½0.1     0.4ï¿½0.1      0.6ï¿½0.2     0.5ï¿½0.2      1.0ï¿½0.3
                          Total decachlorobiphenyl                                                         0.3ï¿½0.2     0.2ï¿½0.1      0.3ï¿½0.2     0.3ï¿½0.2      0.9ï¿½1.0


                          Total PCBs                             4.622.15         28.46.41                 220ï¿½20      380ï¿½49       500ï¿½25      650ï¿½58      830ï¿½110      180,000

                          a Bioconcentration factor = concentration in transplanted oyster tissue at the end of the uptake pcriod/concentration in water.
















                                                                                     TABLE A-9
                            Average PCB Congener Concentrations       I S.D.) in Sediment and Hanna Reef-Ship Channel-Hanna Reef (HRSCHR) Transplanted
                             Oyster Sm, nples During the Depuration Phase of the Experiment at the Hanna Reef Site and Estimated Biological Half-Lives (BHL).


                                                                                                  Depuration phase (days)
                         Analyte                           Sediment             0           3            6           18          30          50        BHL(R2)a
                                                             ng g-l                                          ng g-l

                         18                                                 6.0ï¿½1.0     6.5ï¿½1.9      3.2ï¿½1.3      1.3ï¿½0.3     0.7ï¿½0.3      0.7ï¿½0.2     14(0.82)
                         15/17                                              4.5ï¿½1.3     4.0ï¿½1.2      2.3ï¿½0.2      1.8ï¿½1.0     0.5ï¿½0.3      0.4ï¿½0.1
                         26                                                 30ï¿½9.3        33ï¿½10       16ï¿½1.0       15ï¿½4.6       13ï¿½8.5     5.5ï¿½2.5     22(0.88)
                         50/31                                              9.8ï¿½4.6     4.9ï¿½0.9      3.4ï¿½1.0      2.1ï¿½1.1     3.1ï¿½1.3      3.4ï¿½1.2
                         28                                                 10ï¿½1.4      9.3ï¿½1.2      7.2ï¿½1.7      3.4ï¿½0.7     2.3ï¿½0.3      1.3ï¿½0.3     17(0.96)
                         52                                                 51ï¿½5.4        45ï¿½3.4      33ï¿½8.4       22ï¿½3.2       13ï¿½1.9     15ï¿½3.4      27(0.80)
                         49                                                 29ï¿½1.5        30ï¿½2.8      23ï¿½4.6       18ï¿½3.5       13ï¿½1.1     13ï¿½2.8      39(0.84)
                         47/48fl5                                           18ï¿½2.2        18ï¿½1.8      14ï¿½2.2      9.4ï¿½2.1     7.1ï¿½1.7      6.6ï¿½1.8
                         44                                                 22ï¿½2.3        22ï¿½2.2      16ï¿½3.2      9.7ï¿½2.3     7.2ï¿½1.0      6.7ï¿½2.2     27(0.83)
                         37/42159                                           42ï¿½8.3        25ï¿½8.1      13ï¿½4.3      5.5ï¿½1.9     5.1ï¿½0.2      5.4ï¿½1.9
                         41                                                 20ï¿½1.4        20ï¿½4.2      13ï¿½4.7      7.3ï¿½1.9     5.3ï¿½1.4      5.1ï¿½0.7     23(0.83)
                         40                                                 14ï¿½2.5        13ï¿½0.8     9.0ï¿½2.5      2.3ï¿½1.5     2.5ï¿½2.1      1.3ï¿½0.8     14(0.87)
                         74                                                 13ï¿½2.7        14ï¿½2.2      10ï¿½3.3      6.9ï¿½1.4     5.0ï¿½0.8      4.7ï¿½1.1     30(0.87)
                         70                                                 31ï¿½2.8        34ï¿½3.9      27ï¿½4.3       18ï¿½2.7       12ï¿½0.7     11ï¿½3.3      30(0.88)
                         95                                                 55ï¿½5.3        49ï¿½4.4      45ï¿½6.9       31ï¿½5.2       25ï¿½0.4     26ï¿½5.8      45(0.81)
                         91                                                 24ï¿½8.6        18ï¿½1.4      13ï¿½4.7      7.6ï¿½1.7     5.8ï¿½0.1      5.9ï¿½1.6     25(0.78)
                         60/56                                              10ï¿½1.9        11ï¿½0.8     8.3ï¿½2.0      5.2ï¿½0.9     3.7ï¿½1.0      3.3ï¿½1.0
                         92                                                 22ï¿½8.0        22ï¿½2.4      17ï¿½2.0       11ï¿½2.1     9.4ï¿½1.2      7.8ï¿½2.5     31(0.89)















                                                                                    TABLE A-8
                                                                                      (confinued)



                                                                                                 Depuration phase (days)
                        Analyte                           Sediment             0           3           6            18          30          50       BtIL(R2)a
                                                            ng g-1                                          ng g-1


                        84                                                  29ï¿½0.9       24ï¿½7.3       2015.2      14ï¿½3.0       11ï¿½0.8     11ï¿½3.0     37(0.84)
                        101/90                                              43ï¿½5.2       47ï¿½7.6       43ï¿½8.0      34ï¿½2.3       26ï¿½5.6     26ï¿½3.0     55(0.86)
                        99                                                  29ï¿½1.3       32ï¿½5.4       28ï¿½5.9      21ï¿½2.5       17ï¿½4.3     16ï¿½1.5     49(0.88)
                        97                                                  14ï¿½3.2       16ï¿½2.2       14ï¿½3.6      10ï¿½1.3     9.4ï¿½0.8      10ï¿½2.2
                        87/115                                              20ï¿½1.4       21ï¿½2.6       18ï¿½3.9      12ï¿½1.8       11ï¿½1.4     12ï¿½2.0     55(0.73)
                        1 IOM                                               61ï¿½4.2       61ï¿½6.9       50ï¿½11       32ï¿½8.4       30ï¿½0.9     31ï¿½8.3     45(0.74)
                        82                                                5.9ï¿½1.0      6.5ï¿½1.2      5.1ï¿½2.1      6.2ï¿½2.4     4.0ï¿½0.1     4.6ï¿½0.8
                        151                                               6.0ï¿½1.0      7.5ï¿½0.6      6.8ï¿½2.3      5.0ï¿½1.0     5.0ï¿½1.0     4.9ï¿½0.5
                        135                                               5.0ï¿½0.5      5.7ï¿½0.7      4.9ï¿½1.2      3.3ï¿½0.7     3.8ï¿½0.4     3.7ï¿½0.5
                        107                                               6.6ï¿½1.0      8.3ï¿½3.1      5.7ï¿½1.8      3.5ï¿½1.1     2.7ï¿½0.8     2.6ï¿½0.5     30(0.82)
                        149/123                                             18ï¿½1.7       20ï¿½2.9       19ï¿½3.1      14ï¿½1.6       14ï¿½1.0     16ï¿½1.7     130(0.46)
                        118                                                 34ï¿½2.5       35ï¿½4.5       32ï¿½7.9      25ï¿½2.5       32ï¿½18      23ï¿½1.5     73(0.79)
                        146                                               4.1ï¿½1.1      5.0ï¿½1.3      5.2ï¿½1.1      4.3ï¿½0.9     4.2ï¿½1.7     3.4ï¿½0.5     111(0.60)
                        153/132                                             64ï¿½12        59ï¿½16        48ï¿½13       37ï¿½9.4       33ï¿½7.6     34ï¿½3.5     51(0.71)
                        105                                                 14ï¿½3.0       14ï¿½4.4       14ï¿½5.2     9.6ï¿½1.2     8.8ï¿½1.0     9.0ï¿½1.9     63(0.76)
                        141/179                                           4.7ï¿½0.5      4.1ï¿½1.3      3.0ï¿½0.9      2.1ï¿½0.7     2.1ï¿½0.4     2.0ï¿½0.3
                        138/160                                             28ï¿½4.7       30ï¿½3.8       33ï¿½6.0      25ï¿½4.2       24ï¿½3.8     26ï¿½1.9     200(0.32)
                        187                                                 11ï¿½2.2       11ï¿½3.5     8.1ï¿½1.6      6.7ï¿½2.2     6.5ï¿½1.8     6.6ï¿½0.6     70(0.65)















                                                                                       TABLE A-8
                                                                                         (continued)



                                                                                                     Depuration phase (days)
                         Analyte                            Sediment             0            3            6            18          30           50       Bt]L(R2)a
                                                              ngg-I                                            ng g-l


                         128                                                  3.9ï¿½0.6      4.10.9        4.1ï¿½1.0      2.9ï¿½0.5       2.7ï¿½0.2     2.8ï¿½0.5   76(0.75)
                         177                                                  3.5ï¿½1.6      3.8ï¿½0.8       3.0ï¿½1.4      1.9ï¿½0.5       1.1ï¿½0.9     1.9ï¿½0.1   52(0.83)
                         180                                                  3.8ï¿½1.7      3.9ï¿½0.6       3.7ï¿½0.5      2.7ï¿½0.-5      2.9ï¿½0.6     1.9ï¿½0.4   50(0.94)


                         Total dichlorobiphenyls                              0.1ï¿½0.2
                         Total trichlowbiphenyls                              66ï¿½9.3         73ï¿½13        29ï¿½10         22ï¿½10       20ï¿½9.4      13ï¿½2.9
                         Total teirachlorobiphenyis                           240ï¿½24       230ï¿½17        170ï¿½38       100ï¿½17        75ï¿½5.0      74ï¿½17
                         Total pentachlorobiphenyls                           360ï¿½26       360ï¿½28        310ï¿½76       220ï¿½25        200ï¿½32      190ï¿½30
                         Total hexachlorobiphenyls                            120ï¿½42       140ï¿½25        130ï¿½19         97ï¿½19       91ï¿½14       95ï¿½4.7
                         Total heptachlowbiphenyls                              45ï¿½25        41ï¿½13       32ï¿½9.7       19ï¿½8.1        16ï¿½2.8      16ï¿½1.6
                         Total octachlorobiphenyls                            1.3ï¿½0.9      1.0ï¿½0.2       2.5ï¿½1.7      1.2ï¿½1.5       1.7ï¿½2.7     0.4ï¿½0.5
                         Total nonachlorobiphenyls                            1.0ï¿½0.3      0.7ï¿½0.2       0.9ï¿½1.2      0.4ï¿½0.5       0.2ï¿½0.2     0.4ï¿½0.1
                         Total decachlorobiphenyl                             0.9ï¿½1.0      0.5ï¿½0.4       0.5ï¿½0.9                    0.1ï¿½0.1     0.2ï¿½0.1


                         Total PCBs                                          830ï¿½110       850ï¿½82       670ï¿½120       470ï¿½76        400ï¿½59      380ï¿½50


                         a R2 = square of correlation coefficient for regression equation.
















                                                                                      TABLE A-9
                          Average PCB Congener Concentrations (ï¿½ I S.D.) in Sediment and Ship Channel -to-Hanna Reef (SCHR) Transplanted Oyster Samples
                                    During the Depuration Phase of the Experiment at the Hanna Reef Site and Estimated Biological Half-Lives (BHL).


                                                                                                      Depuration phase (days)
                        Analyte                             Sediment            0            3            6           18           30          50       BHL(R2r
                                                              ng g-I                                          ng 9-1


                        18                                                  6.1ï¿½0.6      6.5ï¿½2.0      3.8ï¿½1.0       2.3ï¿½0.6       1.7ï¿½1.0    1.1ï¿½0.2    19(0.93)
                        15/17                                               4.8ï¿½0.5      4.8ï¿½0.7      4.0ï¿½0.6       2.4ï¿½1.6       1.2ï¿½0.4    0.9ï¿½0.2
                        26                                                   36ï¿½8.0       37ï¿½4.6         28ï¿½11        23ï¿½10       14ï¿½10      7.1ï¿½1.5    22(0.99)
                        50/31                                               5.2ï¿½0.8      7.9ï¿½1.3      3.20.4        6.7ï¿½3.1       7.6ï¿½1.7    5.5ï¿½1.1
                        28                                                  8.0ï¿½1.4      6.5ï¿½0.9      8.5ï¿½0.6       5.3ï¿½0.6       4.2ï¿½1.0    2.9fO.3    34(0.93)
                        52                                                   52ï¿½4.0       46ï¿½7.0       50ï¿½6.1       32ï¿½1.6        30ï¿½9.7     24ï¿½3.5     45(0.91)
                        49                                                   31ï¿½3.2       29ï¿½4.6       32ï¿½5.4       27ï¿½2.4        24ï¿½7.6     17ï¿½1.0     61(0.94)
                        47/48M                                               19ï¿½2.0       17ï¿½1.9       19ï¿½1.8       14ï¿½1.4        13ï¿½3.9     12ï¿½2.0
                        44                                                   20ï¿½3.2       20ï¿½2.2       22ï¿½2.5       15ï¿½0.9        14ï¿½5.0     9.7ï¿½0.8    45(0.94)
                        37/42/59                                             33ï¿½5.3       23ï¿½6.4       18ï¿½3.0       9.5ï¿½0.9       8.1ï¿½2.8    6.6ï¿½0.5
                        41                                                   16ï¿½2.8       16:0.2       16ï¿½3.8       11ï¿½1.2        11ï¿½2.9     9.2ï¿½1.5    55(0.92)
                        40                                                   13ï¿½0.5       11ï¿½1.6       10ï¿½2.3       5.7ï¿½1.4       3.2ï¿½0.9    2.1ï¿½0.2    18(0.97)
                        74                                                   15ï¿½0.9       14ï¿½1.3       15ï¿½0.9       11ï¿½0.7        8.5ï¿½2.2    7.4ï¿½0.7    47(0.95)
                        70                                                   38ï¿½2.0       33ï¿½4.6       36ï¿½3.2       28ï¿½2.9        26ï¿½7.6     20ï¿½2.4     58(0.96)
                        95                                                   63ï¿½8.2       59ï¿½8.4       70ï¿½8.9       54ï¿½4.8        55ï¿½18      44ï¿½0.3     95(0.79)
                        91                                                   22ï¿½1.0       18ï¿½2.7       20ï¿½2.4       13ï¿½1.7        13ï¿½3.9     11ï¿½0.8     50(0.89)
                        60/56                                               9.5ï¿½1.4       10ï¿½1.4       11ï¿½1.4       7.4ï¿½0.5       7.0ï¿½2.6    5.1ï¿½0.3
                        92                                                   26ï¿½6.6       26ï¿½4.8       25ï¿½5.5       20ï¿½2.1        20ï¿½5.9     15ï¿½03      63(0.93)

                                                                                                                                                                                00
















                                                                                       TABLE A-9
                                                                                        (continued)




                                                                                                       Depuration phase (days)
                         Analyte                             Sediment            0            3            6           18           30          50       Bt]L(R2)a
                                                              ng g-I                                           ng g-I


                         84                                                    29ï¿½7.3       31ï¿½3.6       33ï¿½2.7       23ï¿½3.1       23ï¿½8.1     21ï¿½1.4     80(0.79)
                         101/90                                                71ï¿½8.5       69ï¿½7.4       80ï¿½7.1       64ï¿½3.8       62ï¿½12      54ï¿½3.0     91(0.79)
                         99                                                    45ï¿½4.6       44ï¿½4.7       52ï¿½0.6       39ï¿½4.1       3913.3     32ï¿½2.2
                         97                                                    20ï¿½3.7       20ï¿½2.3       25ï¿½1.9       21ï¿½2.3       21ï¿½6.4     21ï¿½2.7
                         87/115                                                32ï¿½3.1       28ï¿½3.9       34ï¿½3.5       27ï¿½2.6       27ï¿½7.6     26ï¿½2.6    132(0.45)
                         1 IOM                                                 80ï¿½12        76ï¿½9.5       88ï¿½10        67ï¿½8.2       58ï¿½8.8     62ï¿½4.7    103(0.67)
                         82                                                    6.3ï¿½2.3    8.5ï¿½0.6        12ï¿½1.1      9.8ï¿½1.7     7.6ï¿½2.1     8.2ï¿½2.0
                         151                                                   10ï¿½2.2       10ï¿½1.0       13ï¿½1.5       11ï¿½0.6       11ï¿½1.7     10ï¿½1.3
                         135                                                   8.7ï¿½2.1    7.3ï¿½1.1       8.9ï¿½1.7      7.5ï¿½0.7     7.4ï¿½1.4     7.1ï¿½1.0
                         107                                                   15ï¿½3.1       11ï¿½4.1       10ï¿½1.1      7.3ï¿½1.0     6.6ï¿½0.7     6.3ï¿½1.4     46(0.75)
                         149/123                                               36ï¿½3.5       31ï¿½3.5       36ï¿½5.1       32ï¿½2.7       33ï¿½6.9     31ï¿½2.0    439(0.24)
                         118                                                   56ï¿½6.3       55ï¿½5.8       68ï¿½7.4        65ï¿½18       55ï¿½5.8     52ï¿½5.3    299(0.19)
                         146                                                   7.8ï¿½2.1    8.0ï¿½1.3        10ï¿½1-9      8.2ï¿½1.2     7.9ï¿½1.9     7.3ï¿½0.9    239(0.27)
                         153/132                                               100ï¿½10       95ï¿½24        98ï¿½27         80ï¿½10       77ï¿½10      72ï¿½5.5    102(0.90)
                         105                                                   17ï¿½6.1       17ï¿½4.7       23ï¿½2.1       20ï¿½2.8       19ï¿½6.4     17ï¿½2.5    120(0.76)
                         141/179                                               5.2ï¿½0.9    5.8ï¿½1.1       5.4ï¿½1.2      4.7ï¿½0.9     4.6ï¿½0.5     4.6ï¿½0.9
                         138/160                                               47ï¿½10        48ï¿½4.0       56ï¿½6.9       49ï¿½4.1       48ï¿½9.7     47ï¿½1.8    595(0.11)
                         187                                                   15ï¿½2.5       14ï¿½1.3       13ï¿½3.2       12ï¿½2.6       13ï¿½1.8     13ï¿½2.1    258(0.56)















                                                                                         TABLE A-9
                                                                                           (continued)



                                                                                                          Depuration phase (days)
                          Analyte                             Sedimcnt             0            3            6            18          30           50        BIIL(R2)a
                                                                ng 9-1                                            ng g-l


                          128                                                   5.9ï¿½1.0      5.9ï¿½0.4      6.9ï¿½0.8       1.2ï¿½0.2      5.5ï¿½2.0      6.4ï¿½1.3  229(0.42)
                          177                                                   4.6ï¿½0.1      3.6ï¿½0.3      4.4ï¿½0.8       3.6ï¿½0.2      3.7ï¿½0.6      3.4ï¿½0.4   145(0.54)
                          180                                                   4.6ï¿½0.2      5.2ï¿½0.8      5.1ï¿½0.7       4.4ï¿½1.4      3.8ï¿½0.5      4.1ï¿½0.9   142(0.63)


                          Total dichlorobiphenyis                                    0.0     0.6ï¿½1.1           0.0      0.4ï¿½0.7      0.3ï¿½0.3          0.0
                          Total trichlorobiphenyis                               71ï¿½12         67ï¿½10      53ï¿½5.1          40ï¿½12        31ï¿½12      19ï¿½3.6
                          Total tetrachlorobiphenyls                            250+71       220ï¿½29       230ï¿½26        160ï¿½9.4      150ï¿½43       120ï¿½11
                          Total pentachlorobiphenyis                            490ï¿½64       470ï¿½42       550ï¿½38        430ï¿½41       390ï¿½59       370ï¿½30
                          Total hexachlorobiphenyis                             230ï¿½31       220ï¿½32       240ï¿½45        200ï¿½16       200ï¿½30       190ï¿½16
                          Total heptachlorobiphenyls                            52ï¿½5.9       47ï¿½1.5       46ï¿½6.3        33ï¿½4.4       31ï¿½6.3       27ï¿½3.0
                          Total octachlorobiphenyls                             1.9ï¿½0.2      1.3ï¿½0.9      2.8ï¿½2.0       0.9ï¿½0.9      0.2ï¿½0.3      0.3ï¿½0.3
                          Total nonachlorobiphenyls                             0.8ï¿½0.3      1.4ï¿½1.0      1.6ï¿½0.7       0.7ï¿½0.4      0.5ï¿½0.2      0.6ï¿½0.2
                          Total decachlombiphenyl                               0.4ï¿½0.3      0.9ï¿½0.7      1.2ï¿½0.3       0.3ï¿½0.3      0.1ï¿½0.1      0.1ï¿½0.1


                          Total PCBs                                          1100ï¿½130     1000ï¿½110      1100ï¿½110       870ï¿½64      800ï¿½140       730ï¿½65


                          a R2 = square of correlation coefficient for regression equation.








                                                                                                     231







                                                        TABLE A-10
                        TBT, DBT and MBT Concentrations in Indigenous Ship Channel and Transplanted Hanna
                                                        Reef Oysters.


                        Sample        Days after        TBT            DBT           MEBT
                                      transplant                    (ng Sn g- 1)


                        Hanna   Reef-to-Ship Channel (HRSC)
                        HRSC             0              40             13               9

                        HRSC             3              68             <5             <5
                        HRSC             7              130            10             <5
                        HRSC            17              210            <5             <5

                        HRSC            30              230              6            <5

                        HRSC            48              360            22             <5


                        Hanna  Reef-Ship Channel-Hanna Reef (HRSCHR)
                        HRSCHR          51              330            <5             <5
                        HRSCHR          54              290            21             <5
                        HRSCHR          66              180            <5             <5

                        HRSCHR          78              130              6            <5

                        FIRSCHR         98              110            <5             <5


                        Ship Channel (SC)
                        SC               3              350            24             <5
                        SC               7                   Sample was not collected
                        SC              17              310            22             <5
                        SC              30              320            32             <5
                        SC              48              390            34             <5


                        Ship Ci,annel-to-Hanna Reef (SCHR)
                        SCHR            51              320            31             <5
                        SCHR            54              340            62             <5
                        SCHR            66              240            24             <5
                        SCHR            .78             220            16             <5
                        SCHR            98              130            10             <5

















                                                                                        TABLE A-11
                        PCB Congener Concentrations in Oysters During Exposure in the Laboratory to a 1: 1: 1: 1 Mixture of Aroclors 1242, 1248, 1254 and 1260
                                                                 and Following Deputation in Contarninant-Free Aquariurns.


                                                                       Uptake phase (days)                            Depuration phase (days)
                        Analyte                           0          3          7          15         30         3          7           15         30         BHL (112)a
                                                                               ngg-1                                            ng g-I


                        18                                          1.36       1.93        3.58       6.46       7.78       6.42        5.77       2.50         28(0.87)
                        15/17                                       0.21       0.54        0.72       1.55       1.61       1.44        1.43       0.66
                        50/31                                       1.02       1.70        3.03       5.54       6.04       4.44        5.34       2.80
                        28                                          1.60       2.93        3.90       8.78       10.6       8.49        9.04       3.90         33(0.78)
                        52                                          2.16       3.22        5.56       12.5       12.9       11.4        10.3       5.17         28(0.96)
                        49                                          1.38       2.42        3.39       8.63       9.03       7.72        7.91       4.04         38(0.86)
                        47/48fl5                                    0.90       1.23        2.85       7.93
                        44                                          1.26       2.03        3.33       8.27       9.10       7.66        7.56       3.65         34(0.87)
                        37/42/59                                    0.87       2.05        3.07       5.64
                        41                                          1.28       2.52        4.46       15.1       14.7       15.4        12.5       4.74         25(0.88)
                        40                                          0.48       0.62        1.09       2.72       3.26       2.59        2.45       1.05         28(0.86)
                        74                                          1.40       1.96        3.82       10.3       10.3       9.29        9.10       6.18         57(0.93)
                        70                                          3.17       4.60        8.29       20.4       21.4       19.5        18.8       112.6        58(0.90)
                        91                                          0.18       0.21        0.51       1.31       1.43       1.51        1.15       1.01         83(0.73)
                        60/56                                       0.97       1.68        2.71       6.93       7.51       7.56        6.06       4.40
                        92                                          0.17       0.16        0.43       1.35       1.53       1.87        1.11       1.18         99(0.31)
















                                                                                             TABLE A-11





                                                                            Uptake phase (days)                            Depuration phase (days)
                            Analyte                            0         3           7          15         30         3          7          15          30         BHL (R2)a
                                                                                   n99-I                                             ng g-I


                            84                                          0.45       0.62        0.97        2.55       2.81       3.04       2.25        1.85        66(0.75)
                            101/190                                     1.92       2.29        4.41        11.2       11.4       11.5   -   9.10        8.55        90(0.83)
                            99                                          1.46       1.42        2.08        5.15       4.61       4.26       4.01        3.73       101 (0.83)
                            97                                          0.70       0.87        1.86        4.31       4.19       3.90       3.86        3.08
                            87/115                                      1.40       1.74        3.19        8.74       9.04       7.39       7.18        5.21
                            110M                                        1.92       2.79        4.85        16.0       13.7       12.6       13.6        10.2        80(0.78)
                            82                                          1.38       1.33        1.84        2.61       2.44       2.65       1.86        2.25
                            151                                         0.41       0.45        1.05        3.00       2.59       2.68       2.38        1.96
                            135                                         0.34       0.40        0.73        2.27       1.76       1.78       1.54        1.60
                            149/123                                     1.45       1.88        3.14        7.49       7.11       7.20       7.90        7.05
                            118                                         2.21       1.86        4.35        10.1       9.74       11.5       10.1        7.71        103(0.58)
                            146                                         0.41       0.50        0.78        1.39       1.55       1.34       1.58
                            153/132                                     2.61       3.23        5.55        17.0       13.5       11.9       11.9        11.1        90(0.59)
                            105                                         0.42       0.46        1.56        3.45       3.51       4.02       2.81        3.38
                            141/179                                     0.47       0.76        0.74        1.82       1.89       1.51       1.33        1.42
                            138/160                                     2.90       4.08        7.24        16.2       14.6       13.6       11.0        10.1        63(0.86)















                                                                                       TABLE A-11
                                                                                         (continued)



                                                                      Uptake phase (days)                          Depuration phase (days)
                        Analyte                          0          3          7         15         30        3          7          15         30          BHL (R2)a
                                                                             ng g-I                                          ng g-l


                        187                                       1.05       1.48        2.20      5.75       4.59       4.20       4.37       4.34
                        128                                       0.30       0.45        0.85      2.01       1.45       1.24       1.05       0.98        48(0.72)
                        177                                       0.35       0.50        0.87      2.36       1.81       1.77       1.62       1.80
                        180                                       0.37       0.40        0.35      0.40       0.18       0.10       0.16       0.08


                        Total dichlorobiphenyls
                        Total trichlorobiphenyls                  4.93       8.21        12.7      24.8       29.7       24.9       24.2       11.7
                        Total tetrachlorobiphenyls                14.9       24.4        41.6       105       95.5       87.7       82.5       47.6
                        Total pentachlorobiphenyls                13.1       14.8        27.6      67.6       64.6       64.7       61.0       49.4
                        Total hexachlorobiphenyls                 9.05       12.0        20.5      51.9       44.8       41.6       36.8       34.6
                        Total heptachlorobiphenyls                2.15       2.82        3.91      9.74       7.46       6.58       6.62       6.62
                        Total octachlorobiphenyls                 0.09       0.12        0.18      0.20       0.32       0.24       0.15       0.35
                        Total nonachlombiphenyis
                        Total decachlombiphenyl


                        Total PCBs                                44.1       62.3        106        259       242        226          211        150


                        a R2 = square of correlation coefficient for mgression equation.















                                                                                          TABLE A-12
                           PCB Congener CDncentrations in Oysteis During Exposure in the Laboratory to a Mixture, of PCBs Plus PAHs and Following Depuration in
                                                                                  Contaminant-Free Aquariums.


                                                                         Uptake phase (days)                           Depuration phase (days)
                           Analyte                          0          3          7          15        30         3          7          15        30          BHL (112)a
                                                                                ng g-I                                          ng g-l

                           18                                         2.25      2.10        6.79       10.5                                                    45(0.82)
                           15/17                                      0.16      0.52        1.23       2.16       1.90       2.35       1.78      1.21
                           50/31                                      0.66      1.53        3.49       7.35       6.32       7.75       5.53      4.22
                           28                                         1.27      2.15        5.57       13.5       11.3       12.0       10.2      7.41         52(0.94)
                           52                                         2.44      2.88        7.13       17.2       16.9       15.8       14.6      11.9         78(1.00)
                           49                                         1.05      2.14        4.87       12.7       10.3       10.1       9.57      8.59         93(0.77)
                           44                                         1.02      1.80        4.65       11.6       10.4       10.6       9.04      6.96         59(0.98)
                           41                                         3.18      2.96        7.95       23.0       21.8       18.6       15.6      11.9         44(0.98)
                           40                                         0.64      0.55        1.34       3.73       3.70       3.44       2.85      2.17         51 (0.99)
                           74                                         2.12      2.65        5.99       16.1       13.5       13.8       12.2      9.50         61 (0.94)
                           70                                         2.14      4.47        11.4       29.1       26.1       25.6       22.9      19.1         74(0.97)
                           91                                         0.34      0.43        0.77       1.75       1.70       1.65       1.51      1.52        143(0.77)
                           60/56                                      0.83      1.72        4.06       10.4       11.3       9.70       8.66      7.21
                           92                                         0.20      0.45        0.97       2.25       2.01       1.98       2.01      1.67        119(0.84)
                           84                                         0.37      0.59        1.49       3.78       3.76                  3.36      2.54         72(0.96)
                           101/90                                     1.30      2.60        6.37       14.4       16.5       13.2       13.7      12.5        155(0.50)
















                                                                                         TABLE A-12
                                                                                            (continued)



                                                                         Uptake phase (days)                          Depuration phase (days)
                          Analyte                           0         3          7          15         30        3         7           15        30           BHL (R2)a
                                                                               ngg-I                                           ng g-1

                          99                                        0.48       1.00         2.18     6.57       5.43       4.80        4.90      4.74         120(0.50)
                          97                                        0.33       0.76         2.12     5.88       4.51       4.27        4.37      3.94
                          87/115                                    0.57       1.47         3.88     11.2       9.61       8.77        7.51      7.22         72(0.79)
                          1 10M                                     0.61       2.35         6.82     20.7       17.7       17.1        15.7      15.6         125(0.65)
                          82                                        1.46       1.60         2.05     3.13       2.32       3.87        2.57      2.01
                          151                                       0.29       0.44         1.34     3.71       2.94       2.50        2.71      2.44
                          135                                       0.30       0.42         0.90     2.42       1.92       1.76        1.61      1.61
                          149/123                                   0.86       1.76         4.08     9.96       9.76       7.90        6.89      7.72
                          118                                       1.31       1.95         5.33     11.8       10.4       9.35        10.7      9.79         272(0.23)
                          146                                       0.33       0.47         0.99     1.21       1.70       1.65        1.75      1.45
                          153/132                                   1.41       3.08         7.69     20.7       13.5       12.9        12.7      13.1         103(0.30)
                          105                                       0.30       0.84         2.12     4.26       5.60       3.77        3.81      4.24
                          141/179                                   0.17       0.35         0.73     1.77       1.59       1.34        1.43      1.22
                          138/160                                   1.96       3.52         7.93     16.5       13.9       11.6        11.5      11.0         86(0.62)
                          187                                       0.73       1.17         2.57     6.16       4.50       4.23        4.29      3.88         89(0.53)
                          128                                       0.21       0.35         0.82     1.82       1.25       1.10        0.95      0.82         44(0.76)
















                                                                                    TABLE A-12
                                                                                       (continued)



                                                                   Uptake phase (days)                           Depuration phase (days)
                     Analyte                           0          3         7          15         30        3           7         15         30         BHL (112)a
                                                                           ngg-I                                        I  ng g-I


                     177                                        0.18       0.43        0.95      2.40       1.82        1.49      1.54       1.56        95(0.38)
                     180                                        0.33       0.24        0.51      0.37       0.19        0.09      0.11       0.18


                     Total dichlorobiphenyls
                     Total trichlorobiphenyls                   5.27       7.58        19.4      37.4       32.5        38.3      28.6       21.0
                     Total tetrachlorobiphenyls                 14.4       20.9        51.7       135       125         118         106      85.2
                     Total pentachlorobiphenyls                 7.44       14.8        37.4      89.4       83.8        74.5      73.7       68.6
                     Total hexachlorobiphenyls                  5.77       10.7        25.1      58.8       47.7        41.9      40,8       40.4
                     Total hCptachlorobiphenyls                 1.35       2.04        4.40      9.70       7.13        6.19      6.27       5.89
                     Total octachlorobiphenyls                  0.09       0.09        0.14      0.12       0.16        0.27      0.11
                     Total nonachlorobiphenyls
                     Total decachlorobiphenyl


                     Total PCBs                                 34.3       56.1        138        330       296         279         255        221


                     a R2 = square of correlation coefficient for regression equation.















                                                                                     TABLE A-13
                             Pblynuclear Aromatic Hydrocarbon Concentrations in Oysters During Exposure in the Laboratory to a Mixture of Selected PAHs and
                                                                  Following Depuration in Contaminant-Free Aquariums.


                                                                     Uptake phase (days)                        Depuration phase (days)
                          Analyte                          0        3          7        15        30         3         7        15        30         BHL (112)a
                                                                            ngg-I                                        ng g-I


                          NaphthWene                       22       26         13       9.4        10        9.8       16       8.6       8.6
                          2-Methyinaphthalene              16       31         21       9.0       8.7        5.9       9.5      5.2       6.8
                          I-Methyinaphthalene              9.0      27         16       6.2       7.7        5.3       9.7      5.0       5.0
                          Biphenyl                         8.3      64         56        37        16        10        11       7.3       6.4
                          2,6-Dimethyinaphibalene          15       57         50        35        13        6.9       12       7.2       7.4
                          Acenaphthylene                   7.3      30         27        24        22        12        13       9.1       5.7
                          Acenaphthene                     4.0      48         48        48        65        9.1       8.8      8.3       5.3
                          2,3,5-Trimethyinaphthalene       26       69         73        61        51        21        23        15        11         16(0.75)
                          Fluorene                         9.3      54         57        48        44        9.1       12       7.9       7.0
                          Phenanthrene                     14       69         64        46        49        25        31        28        22
                          Anthracene                       16       33         42        50        70        24        29        19        13         16(0.68)
                          I-Methylphenanthrene             62       119       115        92        86        37        60        22        19         16(0.72)
                          Fluoranthene                     11       84         91        76       144        44        68        15        11           9(0.78)
                          Pyrene                           16       86         82        88        83        31        47       8.7       8.4           9(0.75)
                          Bm(a)anthracene                  8.3      85         67       154       305        279       228       94        93         16(0.81)
                          Chryscne                         7.7      52         55       112       286        268       276      144       124         22(0.86)
                          Bmzo(b)fluoranthene/
                          Benzo(k)fluoranthene             3.3      183       153       300       7"         705       742      570       330         25(0.94)

                                                                                                                                                                             00















                                                                                    TABLE A-13
                                                                                      (continued)



                                                                    Uptake phase (days)                        Dcpuradon phase (days)
                        Analpe                          0         3          7        15         30        3         7         15         30         BHL (112)a
                                                                          ng g- I                                       ng g-l

                        Benzo(e)pyrene                 4.0        104        92       154        430       436       446        262       174         21(0.93)
                        Benzo(a)pyrene                 6.3         29        16        35         97        61       82          25        17         12(0.87)
                        Perylene                       3.0        8.9        12        22         47        42       45          27        13         15(0.96)
                        Indeno[ 1,2,3-c,dlpytene        10         73        47       102        200       171       137         71        28         10(1.00)
                        Dibenzo(a,h)anthracene         3.0         19       9.6        26         45        36       24          13       6.5         11(0.97)
                        Benzo(g,h,i)peryiene           7.0         36        27        65        144       161       133         94        43         16(0.96)


                        Total 2-Rings                   97                                       106                                       44
                        Total 3-Rings                  113                                       337                                       72
                        Total 4-Rings                   43                                       818                                      237
                        Total 5-Rings                   23                                      1370                                      541
                        Total 6-Rings                   17                                       344                                       71


                        Total PAHs                     293                                      2970                                      965

                        a R2   square of correlation coefficient for regression equation.
















                                                                                           TABLE A-14
                               Polynucl.ear Aromatic Hydrocarbon Concentrations in Oysters During Exposure in the Laboratory to a Mixture of Selected PAHs and
                                                                      Following Depuration in Contaminant-Free Aquariums.


                                                                           Uptake phase (days)                          Depuration phase (days)
                           Analyte*                           0          3          7         15         30        3           7         15         30         BHL (R2)a
                                                                                 ng g-l                                           ng g-I

                           Naphthalene                        22         21         10        9.3        7.9        12         16         17         13
                           2-Methyinaphthalene                16         36         16         10        9.2       9.9         16         14        9.1
                           1 -Methyinaphthalene               9.0        29         12        7.7        5.5       5.8         9.2       9.5        6.8
                           Biphenyl                           8.3        94         49         40         19       9.8         7.9       6.7        5.0
                           2,6-Dimethylnaphthalene            15         81         39         28         27        12         12         13        5.8
                           Accnaphthyleric                    7.3        50         27         36         37        18         11         12        5.1
                           Accnaphthenc                       4.0        74         54         87         49       8.3         7.4       4.8        3.9
                           2,3,5-Trimethylnaphthalenc         26         99         68         56         78        34         28         14        6.9          100.91)
                           Fluorene                           9.3        90         43         62         51        11         12        8.6        5.5
                           Phenanthrene                       14        113         77         56         60        38         37         24         21
                           Anthracene                         16         49         64         81        118        55         45         14        8.9           8(0.89)
                           I-Methylphenanthrene               62        125       123         114        144        78         73         12        8.2           7(0.88)
                           Fluoranthene                       11         84       118         162        194        79         77         11        7.8           7(0.85)
                           Pyrene                             16         81       120         138        150        74         63        9.4        5.4           6(0.89)
                           Benz(a)anthracene                             33         85        169        519       342         238       127         46           9(0.99)
                           Chrysene                                      20         59        120        357       304         198       155         62          12(0.98)
                           Benzo(b)fluoranthene/
                           Benzo(k)fluoranthene                          58       144         317        859       662         521       474        148          13(0.95)

















                                                                                    TABLE A-14
                                                                                       (continued)



                                                                   Uptake phase (days)                         Dcpuration phase (days)
                       Analyte                          0        3           7        15         30        3         7         15         30         BHL (112)a
                                                                          ng 9-1                                         ng g-l


                       Benzo(e)pyrene                              31        88        170       491       452       303        227       120         15(0.98)
                       Bcnzo(a)pyrene                              12        27        57        202        60        37         48        12           9(0.78)
                       Perylene                                   5.2        13        21          65       40        18         20       5.8         10(0.89)
                       Indeno[ 1,2,3-c,dlpyrcnc                    14        42        90        329        113       47         81        14           8(0.78)
                       Dibenzo(a.h)anthracene                     5.6        16        26         72        24       9.4         17       4.5         10(0.69)
                       Benzo(g,h,i)peryiene                       7.4        21        47        136        85        51         50        17         11 (0.92)


                       Total 2-Rings                    97                                       146                                       45
                       Total 3-Rings                   113                                       459                                       53
                       Total 4-Rings                    43                                      1,220                                     120
                       Total 5-Rings,                   23                                     1,690                                      290
                       Total 6-Rings                    17                                       466                                       31


                       Total PAHs                      293                                     3,980                                      540


                       a R2 = square of correlation coefficient for regression equation.







                                                                                                                 242











                                                                 VITA



                               Josd Luis Sericano was born in Puerto Belgrano, Buenos Aires, Repdblica

                            Argentina, on October 10, 1953. He is the son of Vicente Luis and Margarita Sericano.

                            He attended public schools and graduated from Colegio Nacional Punta Alta, Punta

                            Alta, Rep6blica Argentina, in December 197 1. He attended Universidad Nacional del

                            Sur, Bahia Blanca, Repdblica Argentina, and graduated as Quimico, Lic. en Bioquft:nica

                            and Lic. en Qufmica in August 1975, December 1976 and August 1977, respectively.

                            He enrolled in the Graduate College at Texas A&M University in August 1983 and

                            received a M.S. in Oceanography in May, 1986. In February 1981, he married Ndlida

                            Maria Cavallfn and their family consists of one son, Mauro Luis, born in January 1982

                            and one daughter, Gisella Maria, born in June 1987.

                               His permanent mailing address is Murature 68, (8109) Punta Alta, Buenos Aires,

                            Repdblica Argentina.



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