[From the U.S. Government Printing Office, www.gpo.gov]









                            Pesticide Residue
                      Barrier Island Salt Marshes
                  Along the Indian River Lagoon




                                        Submitted to:


                    Florida Department of Environmental Regulation
                            Coastal Zone Management Section
                                    Tallahassee, Florida






                                        Prepared by.-

                                    Mr. James R. David
                        St. Lucie County Mosquito Control District
                                    3151 Will Fee Road
                                 Ft. Pierce, Florida 32982




                                      December 1990
                   Funds for this project were provided by the Department of
             Environmental Regulation, Office of Coastal Management using funds made
              available through the National Oceanic and Atmospheric Administration
                   under the Coastal Zone Management Act of 1972, as amended.



REPORT DOCUMENTATION	1. REPORT NO.		2.		3.
	PAGE	
4.TITLE AND SUBTITLE							5.REPORT DDATE(Preparation)
Pesticide Redidue in Barrier Island Salt Marshes Along the		December 20,1990
Indian River Lagoon
											6.
7.auther(s)
T. Wang (HBOI), R. Parkinson (FIT), J. David (SLCMCD)			8.Performing Organization Rept. NO.
9.performing Organization Name and Address					CM-260
Saint Lucie County Mosquito Control District				10.Project/Task/work Unite No.
315 Will Fee Road									
Fort Pierce, FL 3482								11.Contract(c) or Grant(G) no.
											(c) NA89AA-D-CZ 228
											 (G)
12.Sponsoring Organization Name and Address				13.Type of Report  & Period covered
U.S Dept of Commerce/NOaa		Dept. of Env. Mgmt			Final
OCRM						Coastal Management	
1825 Connecticut A., N.W.		2600 Blair Stone Rd
Washing D.C. 20235			Tallahassee, FL 32399
15.Supplementary Notes

16.Abstract(Unit:200 works)
           
                This project was to document the occurrence and mobility of chlorinated pesticides
         in the St.Lucie County Mosquito Control salt marsh impoundments. A total of 128 sedi-
         ment samples were collected and analyzed. The results show that ten sediment samples
         from eight impoundments were found to contain p,p-DDE. The concentration ranged between
         1.87 ng/g and 31.2 ng/g. Six sediment samples from three impoundments contained dieldrin
         ranging between 2.54 ng/g to 43.2 ng/g. Lindane (y-BHC) was found in most of the impound-
         ments. A total of 33 sediment samples from 11 impoundments were found to contain lindane
         and the concentration ranged between 0.85 ng/g to 34.4 ng/g. Core water samples from each
         impoundment, surface water samples, discharging water from both impoundments 1 and 2, and
         water samples from the Indian River Lagoon were also collected in order to examine the
         potential for water-borne exchange of pesticides between the estuary and the impoundments.
         A total of 146 water samples were analyzed and found to have non-detectable concentrations
         (0.01 ug/1). The study concludes that either lindane, dieldrine, or p,p-DDE were found
         in most of the impoundments. They were largely concentrated in the surficial layer of
         sediment, which had proportionately higher levels of organic muck. Pesticide levels in
         the impoundment waters and adjacent watersof the Indian River Lagoon were non-detectable,
         thus restoration of marsh flushing appears to play no role in pesticide mobility within
         the scope of this study.


       17. Document Analysis a. Discription


         Pesticide; Salt Marsh




         b. Identifiers/Open-Ended terms
            Coastal zone management/





         c. COSATI Field/Group
  16. Availablility Statement					19. Security Class (This Report)		21.No. of Pages
	Unlimited distribution						Unclassified					81
									20.Security Class (This Page)			22. Price




















































































      












                                       EXECUTIVE SUMMARY
                                            CM - 260
            Pesticide Residue in Barrier Island Salt Marshes Along the Indian
                                          River Lagoon
                                 Saint Lucie County, Florida

                 The purpose of the project was to determine the occurrence,
            flux and distribution of chlorinated pesticides in the Mosquito
            Control impoundments of Saint Lucie County and the possible role
            of marsh restoration in their existence and mobility. Ntotal of
            18 impoundments located on the barrier islands between the Indian
            River Lagoon and the Atlantic Ocean (on east coast of Florida)
            were screened by analyzing cores Of sediment, groundwater and.the
            above ground water-column for pesticides.            The presence or
            absence of pesticides in the marsh substrate was established from
            the core samples. Water samples were obtained from each core and
            from perimeter culvert sites and from adjacent marsh and river
            areas, in order to document the presence or absence and mobility
            of the     pesticides in the water         column under contrasting,,.
            management techniques.      Two sediment core samples and,,two core
            hole water samples were collected from each impoundment.i,@,Each,
            core sample was approximately six feet in length and was-
            subdivided into two or three segments for analysis based upam;.
            major lithologic units.       Each sedimeftt@ core was subjedtred t-o.,,.
            grain-size     analysis,    compositional analysis       and/or@  _.-Idunal-
            analysis.    Sediment composition was determined by the Lost om;
            Ignition technique.        The    results of the pesticide surveyi,%
            indicated that 10 sediment samples from eight impoundments were,..,,.-
            found to contain p.pl-DDE (a degradation compound of DDT)4            The,-,@
            detected concentration ranged from 1.87 ng/g at impoundment 10A..:
            (site 2. top layer) to 31.2 ng/g at impoundment 23 (site 1, top,
            layer).    Impoundments 1, 2, 5, 10A, 16A, 18, 19B and 23 were
            detected to contain p,pl-DDE in at least one core sample. These
            impoundments are located on the central and north sections of the,
            study area.       Six sediment samples from three impoundments
            contained dieldrin, ranging from 2.54 ng/g at impoundment 3 (site
            1, middle layer) to 43.2 ng/g at impoundment 3 (site 1, top
            layer).    Lindane ( -BHC) was found in most of the impoundments
            located on both north and south ends of the study@ area.
            Impoundments 5. 71 81 9, 10A, 12r 16Ar 17A, 18, 19B, 23, and 24
            were found      to have lindane contamination.            The detected
            concentration ranged from 0.85 ng/g at impoundment 24 (site'l,
            top layer) to 34.4 ng/g at impoundment 12 (site 2,," top, layer).
            The lindane concentration was higher in the surficial layer,and
            lower in the deeper portions of the sediment samples. The core
            water samples, the marsh surface water samples, the culvert
            discharge water samples and the Indian river water samples did
            not contain detectable levels of pesticide (               0.01. -,g/1).
            Impoundment 1 (unmanaged impoundment) and Impoundment 2 (managed
            impoundment) were selected for detailed water and sediment
            analysis to determine the extent of pesticide contamination.
            Both, core water and sediment cores of the surficial layer of the
            substrate were      collected from 10        and 11 sites In -'each
            impoundment, respectively.       Three sampling sites [Il/T4 (D),









            .Il/T7 (G), and I1/S1] in impoundment 1 contained p,pl-DDE.        The
            concentration ranged between 2.41 ng/g at I1/T4 to 7.54 ng/g at
            Il/T7.   ReSUltB Bhow that most of p,p'-DDE contamination for the
            two_.. impoundments (1 and 2) occurred in the north section of
            impoundment 1. Lindane was found in. four sites in impoundment 2,
            with the concentration ranging front 2.80 ng/g at T3/S3 (1) to
            5.92 ng/g at Tl/S2 (B). Dieldrin concentrations of 15.6 ng/g and
            26.9 ng/g wer 'e also detected in the impoundment 2 sites (at T2/S2
            (E) and T3/S3 (I), reBpectively). Only one Bite in impoundment 2
            contained p,pl-DDE concentration (2.29 ng/g at T1/S3 (C)).*
            Pesticide iesiaue's were non-detectable (      0.01 g/1) in all of
            water samples collected in all of the cores    in impoundments 1 and
            2 during 'the'i'ntensive screening process.       The potential for
            water-borne exchange between the above impoundments and the
            estuary was also examined in this; study, by collecting water
            samples from impoundments 1 and 2; (1) at the end of the open
            session, (@)'au'ring mid-closure period, and (3) at the end of the
            closure period. Samples were taken from; (a) the marsh surface
            50 feet from' culvert in the interior of the impoundments, (b) at
            culvert on the riverside during low tide (while the impoundment
            was discharging), and (c) 100 feet into the river. A total of 88
            exchanging-water samples were analyzed. The pesticide residues
            in all of the water samples were non-detectable even though large
            amounts of organic material were Constantly being exported during
            the closure period through the bottomwater release devices, as
            well as through the open         CUlVertB in the restored areas
            (restoration of flushing) of the impoundments.             The study
            concludes that residues of either lindane, dieldrin or p,p'-DDE,
            which were applied in the 1940's and 19501s, were found in most
            of the    impoundments, but not       at all stations.          Higher
            concentrations were found in the surface layer portion of the
            marsh substrate sampled. Organic muck, which is concentrated in
            the suface layer of the sediments, has a strong tendency to
            adsorb these pesticide compounds.      The more organic matter in
            soil, the longer the pesticides are theorized to persist in it.
            Microbial degradation of these pesticides (DDE, dieldrin, and
            lindane) in the soil play an important role to breakdown these
            compounds, however, in this case there was no strong evidence
            that the bacteria could completely break the pesticides down due
            to their prolonged persistance.          Enhancement of microbial
            activity in the impoundment could POSBibly Btimulate and increase
            the degradation rates of these contaminants in the impoundment.
            In addition, the examination of the effect of the restoration of
            marsh flushing by the Mosquito Control District, within the scope
            of this study, indicated that restoration did not appear to play
            a role in pesticide mobility or pesticide transport from the
            impoundments to the Indian River Lagoon.




                                                                                      0












                                    TABLE OF CONTENTS



                                                                      Section


          Introduction  ...........................................      1

          Geotechnical Analysis   ..................................     2

          Chemical Analysis   ......................................     3

          Controls on Pesticide Distribution and Mobility     ........   4

          Appendix (bound as separate volume)

               Geotechnical Data   .................................     A


               Chemical Data   .....................................     B










                                                                                          I - I--












































                                    SECTION 1


                                  INTRODUCTION






 0-
















                                    Prepared by:

                                Randall W. Parkinson
                           Florida Institute of Technology

                                      Tsen Wang
                       Harbor Branch oceanographic Institute

                                     James David
  0                       St. Lucie County Mosquito Control










  0













                                 TABLE OF CONTENTS


                                                                 Page

        Introduction  ...........................................  1

              Project Goal  ...................................... 1
             Project Description  ...............................  2

        References Cited  .......................................  3





                                  LIST OF FIGURES               Page

        Figure 1 - Regional Location Map of Study Area .........  5

        Figure 2 - Location Map of Culvert Water
                   Sampling Stations: Impoundment 1 ............  6

        Figure 3 - Location Map of Culvert Water
                   Sampling Stations:.Impoundment 2 ............  7

















                                    INTRODUCTION


              The advent of DDT as a contact insecticide in the early 1940's
         marked the beginning of the era of synthetic organic pesticides. A
         large family of organochlorine pesticides emerged and were widely
         used. These pesticides included DDT, BHC, lindane, heptachlor,
         heptachlor epoxide, dieldrin and aldrin. The migration of these
         pesticides into various compartments of the environment has
         generated considerable public apprehension concerning their fate
         and effects. Certain pesticides applied to crops and soil for pest
         and mosquito control do not remain on site, but are transported in
         runoff and on eroded soil particles into receiving waters (1-8)
         where they may be absorbed directly by living organisms (9-13) that
         are subsequently consumed by larger organisms. In this manner,
         organochlorine pesticides may be passed on to secondary consumers
         and up through the food chain. Several instances of poisoning have
         been reported as a final step in the biological magnification
         process (14-17).

              Due to the persistent and long residual effectiveness of the
         pesticides, quantities of DDT, BHC, dieldrin, and chlordane mixed
         with fuel oil were applied from both ground and air by the St.
         Lucie County Mosquito Control District in the late 1940's and early
         1950's (c.f., Annual Reports of the St. Lucie County Mosquito
         Control District, 1947 through 1955). Unknown quantities were also
         applied to the marshes by the military during World War II. Of
         concern in this study are the concentrations of these pesticides
         which may still remain within the marsh substrate.

              How do mosquito control techniques which disturb the marsh
         sediment (e.g., rotary ditching) or modify the exchange of
         estuarine waters (e.g., RIM) influence the concentration or
         mobility of any remaining organochlorine pesticides? As a first
         approximation, both mosquito control techniques described above
         could increase the flux of these compounds (if present) into the
         Indian River Lagoon (IRL).


                                    Project Goal


              The goal of this project is to (1) document the presence or
         absence of chlorinated pesticides within the marsh substrate of 18
         St. Lucie County mosquito control impoundments along the IRL
         (Figure 1), and (2) document the mobility of these pesticides into
         the IRL under contrasting marsh management techniques (well-flushed
         vs. poorly flushed).

              This project makes two important contributions in the area of
         mosquito control and coastal zone management: (1) immediately
         improving the decision making capabilities of the St. Lucie County
         Mosquito Control District by providing additional baseline data,














          2

          and (2) documenting the effect of standard impoundment management
          techniques on Indian River water quality.


                                  Project Description


               The project consists of two components: (1) screening of all
          impoundments for the presence -of pesticides and (:2) detailed
          analysis of pesticide distribution and mobility associated with 2
          impoundments managed under contrasting hydrodynamic conditions
          (e.g., well-flushed vs. poorly-flushed).

               Eighteen impoundments are located within the St. Lucie County
          Mosquito Control District (Figure 1). All 18 were screened for the
          presence of pesticides using 2 randoml- selected sediment cores. In
                                                 y
          addition, 2 water samples were collected from the base of each core
          hole.


               Two impoundments were selected for detailed study. one
          impoundment (#1) covers 639 acres and is connected to the IRL by 5
          culverts (Figure 1 and 2). It is considered to be a poorly-flushed
          impoundment (acreage:culvert = 128) as the impounded water levels
          oscillate only a few centimeters over the tidal cycle (range -1.3
          ft). In contrast Impoundment #2 covers 188 acres and -LS connected
          to the IRL by 7 culverts (Figure 1 and 3). It is considered to be
          a well-flushed impoundment (acreage: culvert = 27) with little tidal
          dampening (<10%) or time lag observed.

               In addition to the detailed sampling of the marsh substrate,
          3 field sessions focused on the characteristics of the waters
          exchanging between the 2 impoundments selected for detailed study
          and the estuary. Water samples were collected (1) at the end of the
          open season, when the marsh exchanges freely with the estuary, (2)
          at the end of the closed season, when the marsh is isolated from
          the estuary, and (3) at drawdown, when the impoundments are
          completely drained during the mid-closure period (Impoundment 2
          only).

               The following three sections describe (1) geotechnical methods
          and results, (2) chemical methods and results, and (3) data
          synthesis and discussion.
















                                     REFERENCES CITED


          1. Grzenda, A.R. A five-year statistical survey of cotton
          insecticides usage in a large Alabama watershed. J. Georgia
          Entomol. Soc. 1:1-11, 1966.

          2. Grzenda, A.R., G.J. Lauer, and H.P. Nicholson. Insecticide
          contamination in a farm pond. Part II. Biological effects. Trans.
          Amer. Fish. Soc. 91:217-222, 1962.

          3. Grzenda, A. R. , H. P. Nicholson, J. I. Teasley and J. H. Patric. DDT
          residues in mountain stream water as influenced by treatment
          practices. J. Econ. Entomol. 57:615-618, 1964.

          4. Grzenda, A.R., and H.P. Nicholson. The distribution and
          magnitude of insecticide residues among various components of a
          stream system. Univ. of North Carolina. Proc. S.         Water Resour.
          Pollut. Contr. Conf. 14:165-174, 1965.

          5. Lauer, G.J., H.P. Nicholson, W.S. Cos and J.I. Teasley.
          Pesticide contamination of surface water by sugar cane farming in
          Louisiana. Trans. Amer. Fish. Soc. 95:310-316, 1966.

          6. Nicholson, H.P., A.R. Grzenda, G.J. Lauer, W.S. Cox and J.I.
          Teasley. Water pollution by insecticides in an agricultural river
          basin. I. Occurrence in river and treated municipal water. Limnol.
          Oceanogr. 9:310-317, 1967.

          7. Nicholson, H.P., A.R. Grzenda and J.I. Teasley. Water pollution
          by insecticides. A six and one-half year study of a watershed.
          Proc. Symp. Agr. Waste Water. 10:132-141, Water Resurces Centr,
          Univ. Calif., Davis, Calif., 1966.

          8. Nicholson, H.P., H.J. Webb, G.J. Lauer, R.E. O'Brien, A.R.
          Grzenda and D.W. Shanklin. Insecticide contamination in a farm
          pond. Part I. Origin and duration. Trans. Amer. Fish. Soc. 91:213-
          222, 1962.

          9. Kolipinski, M.C., A.L. Hinger and M.L. Yates. Organochlorine
          insecticide residues in Everglades National Park and Loxahatchee
          National Wildlife Refuge, Florida. Pesticide Monitoring Journal
          5(3):281-288, 1971.

          10. Seba, D.B. and E.F. Corcoran. Surface slicks as concentrations
          of pesticides in the marine environment. Pesticide Monitoring
          Journal 3(3):190-193, 1969.

          11. Wang, T.C. Toxic substance monitoring in the Indian River
          Lagoon, Florida 46(3):286-295, 1983.













          4

          12. Wang, T.C., R.S. Johnson and J.D. Krivan. Residues of
          polychlorinated biphenyls and DDT in water and sediment of the St.
          Lucie Estuary, Florida. Journal of Pesticide Monitoring 13(2):69-
          71.

          13. Wang, T. C. , R. S. Johnson and J. D. Krivan. Reconnaissance of
          polychlorinated biphenyls and DDT residues in water and sediment of
          the Indian River Lagoon, Florida, 1977-1978. Journal of Pesticide
          Monitoring 13(4):141-144.

          14. Hunt, E.G. and A.I. Bischoff. Calif. Fish Game 46:91, 1960.

          15. Hunt, E. G. Scientific aspects of Pest Control. Nat. Acad. Sci.
          Nat. Res. Council Pub. No. 1402, 1966.

          16. Keith, J.0. J. Appl. Ecol. 1966., 71, 1966.

          17. Burdick, G.E., E.J. Harris, H.J. Dean, T.M. Walker, J. Skea,
          and D. Colby. Trans. Amer. Fisheries Soc. 93:127, 1964.

          18. U.S. Environmental Protection Agency. Pesticide Monitoring
          Manual, Bay St. Louis, Miss. 39520, 1972.








                                                      Imp. 24                                    5
                                                       Imp. 23


                                                         Imp. 19B
                                                                                    Atlantic
                                                                                     Ocean
                                                           Imp. 19A
                                             V              Imp. 16A
                                                             Imp. 17A

                                                              Imp. 18A

                                                                 Fort Pierce Inlet





                                                                   Imp. 1

                                                                     Imp. 2


                                                                      Imp. 3
                                                                        Imp. 4



                                                                           Imp. 5
                                                       7::: ...

                                                                              Imp. 6

                                                                                Imp. 7

                                                                                  Imp. 8


                                                                                    Imp. 9




                                                                                        Imp. I OA





                                                                                             Imp. 12




                        Figure I       Regional Location Map of Study Area














           6



                                IARIOO                                       North

                          1BR100   1A R

                              1 BCR

                                        0 1 AM50

                                    0 1 BM50





















                                   Indian
                                   River
                                  Lagoon                 Impoundment 1







                                                         Culverts




                                         Dike
                                     C



































                 Figure 2    Location-of Culvert Water Sampling Stations:
                                         Impoundment 1













































                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           I I
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           I. . . . . . . . I                   rll@)










                                                                                                                                                                                                                                                                                                                                                                                                                                                                      SECTION 2


                                                                                                                                                                                                                                                                                                                                                                                GEOTECHNICAL ANALYSIS






 0-















                                    Prepared by:

                                Randall W. Parkinson
                           Florida Institute of Technology

                                         and


                                     John White
                           Florida Institute of Technology
  0











  0





                                  TABLE OF CONTENTS                Page

         Geotechnical Methods  ...................................    1


              Selection of Field Stations   .......................   1


                    Impoundment survey  ...........................   1
                    Detailed impoundment sampling  ................   1
                    Water sampling stations  ......................   2

              Sample Collection  .................................    2

                    General procedures  ...........................   2
                    Core collection  ..............................   2
                    Water sample collection  ......................   3

              Geotechnical Analysis   .............................   4

                    Sediment cores  ...............................   4
                    Water samples  ................................   4

         Geotechnical Results  ...................................    5


              Cores .............................................     5


                    General observations  .........................   5
                    Specific observations  ........................   5

              Culvert Water Samples   .............................   6

         Discussion of Geotechnical Results   .....................   8

              Significance of Sediment Types   ....................   8

              Anticipated Pesticide Sediment Intervals    ..........  8

         References Cited  .......................................    10













                                     FIGURE CAPTIONS


                                                                     Page

         Figure 1 -    Regional location map of study area    ........ 11

         Figure 2 -    Core locations: Impoundment 1   ..............  12

         Figure 3 -    Core locations: Impoundment 2   ..............  13

         Figure 4 -    Location of culvert water samples:
                       Impoundment 1  ..............................   14

         Figure 5 -    Location of culvert water samples:
                       Impoundment 2  ..............................   15

         Figure 6 -    Weight percent TOM vs depth: 18
                       general survey cores   .......................  16

         Figure 7 -    Weight percent clastics vs depth: 18
                       general survey cores   .......................  17

         Figure 8 -    Weight percent calcium carbonate vs
                       depth: 18 general survey cores   .............  18

         Figure 9 -    Culvert water sample data:
                       Impoundment 1 POM  ..........................   19

         Figure 10 -   Culvert water sample data:
                       Impoundment 2 POM  ..........................   20
















                               GEOTECHNICAL METHODS



                            Selection of Field Stations



        impoundment Survey



             The initial phase of field work consisted of the collection of
        two sediment cores from all 18 mosquito control impoundments on the
        St. Lucie County barrier island (Figure 1). These were collected
        from sites determined in a random or haphazard fashion. If an
        impoundment was dissected by the coastal highway (AlA), one site
        was established on each side of the highway. The point of entry
        into the impoundment was selected by Mr. James David (St. Lucie
        County Mosquito Control) . Site selection was based upon: (1)
        accessibility, (2) proximity to probable historical application
        sites, (3) the degree to which marsh sediments had been disturbed
        by post application activity, and (4) degree of flushing by
        mosquito control water management programs. Entry points were
        either located along the coastal highway or the dike which
        separates each impound  'ment from the Indian River Lagoon. The
        distance traveled. into the impoundment was determined using a
        random number generator and ranged from between 0 and 100 feet. If
  0     the point of entry was from the highway, an additional 100 feet was
        added to the random number to avoid sampling an area of the
        impoundment that may have been altered by road construction.
        Location of all cores obtained during random screening of 18
        impoundments are shown in Appendix Al.


        .Detailed Impoundment Sampling


              Impoundments 1 and 2 (Figure 1) were initially proposed to be
        the sites of a detailed geotechnical and chemical survey. This
        selection was based upon the fact that these two impoundments were
        located immediately adjacent to the city of Ft. Pierce and
        therefore they were most likely to have been treated in an effort
        to reduce the urban mosquito and sandfly problem. The results of
        the random pesticide survey confirmed this speculation as three of
        the four random cores collected from Impoundments 1 and 2 contained
        pesticides. These two impoudments were also selected for study
        because one (#1) is considered poorly flushed (acreage:culvert
        128) and the other (#2) well flushed (acreage:culvert = 27). Hence
        the influence of water management on pesticide distribution and
        mobility could also be addressed in this study.

              Detailed  coring transects were established         for each
        impoundment (Figure 2 and 3). The transects were initially laid out
        in a grid like fashion to maximize coverage of the impoundment.














          2

          Impoundment 2 was small enough that the planned coring program was
          accomplished and a total of 11 cores were collected (including the
          two randomly selected cores) . The center of Impoundment 1 proved to
          be inaccessible. A total of 10 cores (including the two randomly
          selected cores) were collected although none were taken from the
          center of the impoundment.


          Water Sampling Stations


               Pore water samples were taken at each core site. These were
          taken from waters that entered the void created by removal of the
          sediment core. In addition, a water sampling program was
          established in the viscinity of Impoundment 1 and 2, adjacent to
          culverts which pass through the dike and connect the impoundment
          perimeter ditch to the Indian River Lagoon. The culverts to be
          monitored were selected by Mr. James David (St. Lucie County
          Mosquito Control District) . Selection was limited to sites of
          continuous bottom water release. Ficlure 4 and 5 illustrate the
          location of sampling stations.


                                   Sample Collection



          General Procedures



               All sampling containers used in this study were composed of
          either glass or metal. No plastic material was allowed to come into
          contact with the samples. All glass containers used for storage of
          water samples were cleaned using the laboratory techniques of Dr.
          Tsen Wang. Any object that was to be reused in a field sampling
          procedure was cleansed using distilled water and subjected to a
          final rinse of acetone. If a sample was not subjected -to immediate
          analysis after returning from the field, it was temporarily stored
          in a refrigerated room.


          Core Collection



               At each core site a 311 diameter aluminum pipe was forced into
          the soil using brute force and pounding weight. The initial meter
          or so of penetration was typically quick and easy, reflecting the
          constitution of the marshy substrate. Penetration eventually
          stopped at a depth of between 1 and 2 meters. At that time the core
          was driven still further into the soil using a pounding weight.
          This ensured that the core sample completely penetrated through the
          marsh sediments and into premarsh sediments. After removing each
          core, the base was inspected to ensure that it had penetrated














                                                                           3

         completely through the marsh sediment sequence. If the initial
         attempt was unsuccessful, another core was taken. The core was then
         sealed and returned to the laboratory refrigeration unit where it
         was stored in an upright position.


         Water Sample Collection



              Water samples collected from the core holes were recovered
         using a 100 ml glass dipper. The dipper was inserted towards the
         base of the hole and upon filling, was transferred into a four
         liter glass jar. Water sampling was repeated until the four liter
         jar was full. During the screening of the 18 impoundments, water
         levels were low and most of the water sampled from the core holes
         was collected at the base as it began to fill the void space. Two
         core sites (Impoundment 23, site 2 and Impoundment 18, site 1)
         yielded no water.

              Impoundments 1 and 2 were partially submerged at the time the
         detailed sampling program was initiated. Therefore, core holes
         immediately filled upon removal of the core tubing. Water samples
         were collected by submerging a "corked" dipper about 25 cm into the
         hole and was then uncorked to collect the water sample. The core
         was withdrawn as slowly as possible in an attempt to maximize the
         volume of pore water to enter the void and minimize the volume of
         surface water collected.


              All core hole water samples were transferred to the HBOI
         refrigeration unit within 4 hrs.

              Culvert water sampling was conducted on three separate
         occasions during the project: (1) at the end of the open period,
         when estuarine water circulated freely through the culverts during
         the tidal cycle, (2) after opening the culverts at the end of the
         closed period, when the impounded marsh surface was kept submerged
         by mechanical pumping and closure of culverts, and (3) during mid-
         closure drawdown, when impounded water was released to draw down
         the water levels (Impoundment 2 only). During each sampling event,
         water was collected at three stations (Figure 4 and 5) once a day
         over a five day period. The samples were always taken while water
         was draining the impoundment.

              Water samples were collected at the three culvert stations by
         submerging a one liter glass jar about 25 cm below the water
         surface. Two samples were collected at each station. one was
         delivered to HBOI within 3 hrs and subjected to chemical analysis
         at a later date. The other sample was stored at FIT in a
         refrigeration unit until it was subjected to further geotechnical
         analysis (described below).











                                   Geotechnical Analysis


           Sediment Cores



                Sediment cores were split longitudinally, photographed, and
           measured. A core log was generated by visually describing the
           sediment according to its texture and composition.

                Based upon visual inspection, each core was subdivided into
           major lithologic units. For detailed geotechnical analysis, 5 cm
           thick sediment samples were collected at 30 cm intervals or at the
           contact between two major lithologic units. Utilizing the other
           half of the core, a continuous sediment sample was taken from
           within each major lithologic unit. This typically generated three
           pesticide samples which were transferred to HBOI. Chemical analysis
           of the survey cores indicated that if pesticides were present at a
           core site they were present at the surface. Therefore, during the
           detailed survey of pesticide distribution in Impoundments 1 and 2
           only surface samples were analysized for pesticides.

                Each sediment subsample was subjected to one or more of the
           following laboratory procedures: (1) grain size analysis, (2)
           compositional analysis, and (3) faunal analysis. Standard sieve
           analysis was used during this project to determine weight percent
           gravel (>2mm), sand (<2mm but >62 um), and mud (<62um).

                Sediment composition was determined using the Loss on Ignition
           (LOI)   technique   described by Dean        (1974).   This    procedure
           distinguished between total organic matter (TOM), carbonate, and
           noncombustibles (primarily clastic sediment).

                Faunal elements were identified using Abbott (1974).


           Water Samples



                Water samples collect during the three sampling intervals were
           filtered through preweighed 0.45 um opening paper. Total
           particulate organic matter (POM) was then determined by LOI
           following the techniques of Dean (1974). A number of blanks were
           also run to determine the accuracy of this technique.















                               GEOTECHNICAL RESULTS



             Appendix A2 contains all of the geotechnical data including
        sediment description, composition, geotechnical sample location,
        grain size, and fauna. In addition chemical sample intervals and
        concentrations are also shown. The results of the geotechical
        analysis are decribed below.



                                       Cores



        General Observations



             In general, the sediment cores collected during this study
        consisted of an upper, organic rich mud or muddy peat underlain by
        a skeletal sand. The presence of large amounts of organic material
        within the upper portion of most cores made standard grain size
        analysis inappropriate. The organic  'material binds the sediment to
        generate an apparent grain size distribution that does not reflect
        the true sediment size, but instead, the size distribution of bound
        sediment clumps and detritus. Therefore, trends in grain size were
        not determined independently, but inferred from the visual core
        descriptions.

             Compositional trends were effectively determined using the LOI
        technique.

             In only 5% of the samples were faunal elements identifiable.
        All other samples were barren or contained skeletal material that
        was chemically or physically degraded to such an extent that
        recognition was not possible.

             In general, the thickness of the sediment sequence recovered
        by coring was less than the actual depth to which the core
        penetrated the marsh. This is commonly referred to as compaction.
        For example, assume a core penetrated 1 m of marsh but upon opening
        the core only 0.5 m of sediment was present. The sediment is
        assumed to have compacted 50%. This is common      in water laden,
        organic rich marsh soils. No attempt was made to "decompact" the
        cores   because    different   sediment    types   have    different
        compactibility. All sediment depths discussed in this report were
        measured directly for the compacted core.


        Specific Observations


             Four major sediment types were recognized in the impoundment
        cores. They are as follows:













          6

                (1) Mangrove peat and detritus: A brownish, spongy sediment
          consisting of between 30 and 80 wt% organic material. The organic
          material consisted of fibrous rootlets, roots, and leaf material.
          Mud content varied inversely with organic content. The sediment
          averaged about 0.5 m in thickness.

                (2) Muddy quartz sand: A tan or light brown, muddy, fine to-
          medium grained quartz sand. Visible rooting and rootlets were
          recognizible. organic content varied between 5 and 20 wt%. -Mud
          content averaged about 10%. The sediment appeared mottled; a
          consequence of the irregular distribution of mud. Typical
          thicknesses were about 0.4 m.

                (3) Skeletal quartz sand: A light gray, clean, medium grained
          skeletal quartz sand. Skeletal content ranged from between 5 and 35
          wt%. Shells were very poorly preserved, except within discrete
          shell layers or towards the base of the sequence. Organic contents
          were typically <5%. Sediment thickness could not be determined
          because the cores never penetrated completely through this sediment
          type.

                (4) Mud: Typically blue-gray, although white and medium gray
          examples were also encountered. organic contents averaged between
          10 and 20 wt%. Rarely contained any material >62um. Some mangrove
          roots were identified. Thickness averaged <0.4m.

                The sediments described above typically were found to occur in
          a repeatable sequence consisting of (in descending order) : (1)
          mangrove peat or mud, (2) muddy quartz sand, and (3) skeletal
          quartz sand. only Impoundments 23 and 24 did not yield this
          sequence. In these impoundments the muddy quartz sand was exposed
          at the surface and underlain by skeletal quartz sand. Both of these
          areas are at high marsh elevations and lack red mangrove
          vegatation.

                The compositional trend generated by this sediment sequence
          was one of decreasing organic content and increasing clastic
          content with depth (Figure 6 and 7). Calcium carbonate values were
          low and did not vary as a function of depth (Figure 8).


                                 Culvert Water Samples


                Average POM data for the culvert transects is shown in Figures
          9 and 10. Each data point represents the mean value of five samples
          collected over a five day interval. Raw data is included in
          Appendix A3. Impoundment 1 water samples were collected at the end
          of the open period and end of the closed period. Except for the
          marsh stations sampled at the end of the closed period, there is no
          significant difference between the samples as a function of culvert
          location, station location, or sample period. The marsh stations














                                                                            7

        yielded statistically higher POM at the end of the closed period.

              Impoundment 2 water samples were collected at the end of the
        open period, end of the close period and during mid-closure
        drawdown. There is no significant difference between the samples as
        a function of culvert location, station location or sample period.













           8


                            DISCUSSION OF GEOTECHNICAL RESULTS



                              Significance of Sediment Types


                Sediment types 1 and 4, which were always found at the top of
           cores, are clearly a product of sedimentation processes currently
           active in the impoundments. -Sediment type 1 is a mangrove
           associated deposit. The origin of sediment type 4 remains
           enigmatic. It always lies above sediment type 2 and at the same
           stratigraphic position as sediment type 1. Therefore it is
           interpreted to have been deposited within a marsh environment.

                Sediment type 2, the muddy quartz sand, consistently occurred
           beneath sediment type 1 or 4 and above sediment type 3. This
           sequence is interpreted to have been deposited prior to marsh
           formation, perhaps as a barrier island overwash fan or inlet
           related backbarrier deposit. Shell, when present, consisted of
           trace (<5%) amounts of unrecognizable skeletal fragments that were
           usually abrained and etched.

                The rooting within sediment type 2 is interpreted to have
           developed as coastal vegetation associated with sediment type 1
           colonized the surface of this sedimentary deposit.

                Sediment   type -3,    a   clean,   skeletal   quartz   sand,    is
           distinguished from sediment type 2 by the abundance of skeletal
           material and paucity of rooting, although the contact between
           sediment type 2 and 3 is often gradational. These distinctions
           suggest that sediment types 2 and 3 are genetically related. In all
           likelihood they were probably deposited within the same
           depositional environment as a single unit. Post depositional
           modification by rooting, slowly transformed the upper layers of a
           clean, skeletal sand (sediment type 3) into a muddy quartz sand
           (sediment type 2). The absence of significant quantities of
           skeletal material within sediment type 2 can be attributed to the
           slightly acidic groundwater conditions that are often associated
           with organic rich marsh sediments. Skeletal material within
           sediment type 3 was difficult to identify but appeared to consist
           primarily of a restricted marine fauna (e.g., Anomolacardia sp.,
           Cerithium sp.)


                        Anticipated Pesticide Sediment Intervals


                Based upon the sedimentological evidence provided above, it is
           most probable that Sediment Types 1 and 4 were present at the land-
           air interface at the time the impoundments were treated with
           organoclorine pesticides. Sediment types 2 and 3 were not exposed
           to direct treatment and could only have acquired pesticides through






 0                                                                       9
        vertical and lateral migration away from the contaminated surface
        layer.























  0











 0                                                                   -





          10                      REFERENCES CITED

          Abbott, R.T., 1974, American Seashells: The marine of the
                Atlantic and Pacific coasts of North America: 2nd Edition,
                van Norstrand Reinhold, New York, 663 p.

          Dean Jr., W.E., 1974, Netermination of carbonate and organic
                matter in calcareous sediments and sedimentary rocks by
                loss on ignition: comparison with other methods: Journal of
                Sedimentary Petrology, v. 44, p. 242-248.







                                          Al       Imp. 24

                                                    Imp, 23


                                                      Imp. 19B
                                                                                 Atlantic
                                                                                 Ocean
                                                        m
                                                        I p 19A
                                                         Imp. 16A
                                                          Imp. 17A

                                                           Imp. 18A

                                                             Fort Pierce Inlet





                                                                Imp. 1

                                                                 Imp. 2


                                                                   Imp. 3
                                                                    Imp. 4



                                                                        Imp. 5


                                                                          Imp. 6

                                                                             Imp. 7

                                                                              Imp. 8


                                                                                Imp. 9




                                                                                    Imp. I OA





                                                                                         Imp. 12



                        Figure 1      Regional location map of study area














               12





                        0                  1309                                                 Noith



                            Scale in Feet
                                                          T5

                                                                      S1



                   Indian River Lagoon




                                             T4                                      T6

                                                                       T-7







                                                                                     AM




                                              T3







                                                                          T8


                                          T2






                                              T1




                           Key

                        Pesticide Core

                        Non-Pesticide Core







                                Figure 2 - Core locations: Impoundment 1













                                                                                                              13







                   0                     1309
                                                                                                  North

                         Scale in Feet










                           Indian River Lagoon


                                                                   S2
                                                                 0        AlA
                                                         T3/3   T3/2 T3/1
                                                         0      0      0


                                                       T2/3    T2/2    T2/1
                                                        M       0      M



                                                        T1 /3  T1/2     T1/1













                                                           Key

                                                        Pesticide Core

                                                        Non-Pesticide Core




                                Figure 3         Core locations: Impoundment 2













            14




                             1 AR1 00                                     North

                      1BR100    1ACR

                           1 BCR


                                       1AM50

                                 0 1 BM50





















                                Indian
                                River
                               Lago,on                Impoundment 1







                                                       Culverts




                                      Dike







              Figure 4     Location of culvert water samples: Impoundment














                                                                                15










                                                            Indian
                                                            River
                                                           Lagoon
                                                                          Ov
                     North                             Culverts          Q,

                                                                          Al

                                                          Dike












                    213CR    2BM50          2AM50
                    0  0    0                 0
                2B R1 00
                                       2ACR 0


                                           0
                                     2AR100













             Figure 5 - Location of culver water samples: Impoundment 2













           16








                              Weight Percent TOM Vs DEPTH
                                    Cores From General Impoundment
                                           Pesticide Survey



                        0



                         ..... .... . .. .


                      -50


                D
                e
                p     100 -4,                       . ... ...
                t
                h


                    -150      ............. ..--. .. .....-. .. ...... ...... ........




                    -200
                        0         20        40        60         80        100
                                          Weight Percent TOM


                                            Sediment Samples














           Figure 6 - Weight percent TOM vs depth: 18 general survey cores













                                                                           17








                        Weight Percent NONCOMBUSTABLE Vs DEPTH
                                   Cores From General Impoundment
                                          Pesticide Survey



                       0




                    -50-


               D
               e
               p  -100-
               t
               h

                   -150 . . ....... . ...




                   -200
                       0        20         40        60        80         100
                               Weight Percent Noncombustable (Clastics)


                                           Sediment Samples














                   Figure 7 - Weight percent clastics vs depth:
                                   cores 18 general survey














         18







                           Weight Percent CaC03 Vs DEPTH
                                  Cores From General Impoundment
                                         Pesticide Survey



                      0




                    -50


               D
               e
               p   -100
               t
               h

                   -150            . .......             ......... ....




                   -200
                      0         20       40        60        80        100
                                      Weight Percent CaC03


                                         Sediment Samples













                      Figure 8 - Weight percent CaC03 vs depth:
                               18 general survey cores







                                                    IMPOUNDMENT1                                           19
                                                        End of Open Period




                       Ld

                              20--

                       LL-
                       0
                       cy-    15--
                       LLJ
                       F-




                       0


                                                r                       T
                                         t
                                                L
                               0         i                              i
                                      R100     CR     M50            R100     CR     M50


                                                    STATION      LOCATION






                                                    IMPOUNDMENT1
                                                      End of Closed Period


                              40-


                       Ui


                              30--
                       U-
                              25--

                       Lj
                              20--


                              15--
                       0
                       CL     10--
                       0                                                f
                                                                        t
                               0
                                      R100     CR     M50            R100     CR     M50


                                                    STATION      LOCATION



                   Figure 9 - Culvert water sample data: Impoundment 1 POM








                                                                                IMPOUNDMENT 2
                                                                                     End of Open Period

                                                          25-
                   20                              Ld
                                                   <      20--


                                                   0
                                                   Of     15--
                                                   Ld


                                                          10--

                                                   0
                                                   CL                        f
                                                                     T                              T
                                                                             t                      L        T
                                                           0
                                                                  R100       CR    M50           R100        CR   M50


                                                                                STATION      LOCATION


                                                                                IMPOUNDMENT 2
                                                                                   Mid-Season Drowdown


                                                          25



                                                          70--



                                                          15--


                                                   _j
                                                          101

                                                   0
                                                                             T                                     T
                                                                                                             r



                                                           0                        4-
                                                                  RIOO       CR    M50           R100        CR   M50


                                                                                STATION LOCATION

                                                                                IMPOUNDMENT 2
                                                                                   End of Closed Period


                                                          25-



                                                          20--


                                                   0
                                                   ck@    15


                                                   _j



                                                                     T
                                                           5--      T
                                                                     1       et

                                                           0                 -4     i               l'-      -4    4-
                                                                  11100      CR    M50            RIOO       CR   M50


                                                                                STATION       LOCATION


                             Figure 10               Culvert water sample data:                              Impoundment 2 POM



















































                                        SECTION 3


                                  CHEMICAL ANALYSIS










                                                                                                   ...



                                                                                                  kill
                                                                                 -                -,I- U4
                                                                                                  t














               Pesticide Residue Occurrence and Distribution in the St. Lucie County
                               Mosquito Control Impoundments, Florida












                                              Tsen Wang
                               Harbor Branch Oceanographic Institution
                                         Ft. Pierce, Florida
                                          December 15, 1990













                                          Table of Contents



                  Section                                                      Paqe
                  Summary                                                        3

                  Methods and Procedures                                         4

                  Results and Discussion                                         5

                  Table 1. Analytical Procedures for Water Samples               7

                  Table 2. Analytical Procedures for Sediment Samples            8

                  Table 3. Gas Chromatographic Operating Conditions and          9
                      Calibration Curves
                  Table 4. Quality Control for Water Sample Analysis             10

                  Table 5. Gas Chromatographic/Mass Spectrometer (ITD)           11
                      Operating Conditions
                  Table 6. Quality Control for Sediment Sample Analysis          12

                  Table 7. Summary of Detected Compounds in the Sediment         13
                      Samples at Each Impoundment (ng/g)
                  Table 8. Summary of Transect Sediment Sampling for             15
                      Impoundments 1 and 2
                  Figure 1. Location and Distribution of Detected Chlorinated    16
                      Pesticides in each Impoundment
                  Figure 2A - 2L. Pesticide Distribution in the Sediment at      17
                      each Impoundment
                  Figure 3A. Transect Sediment Sampling at Impoundment 1         29

                  Figure 3B. Transect Sediment Sampling at Impoundment 2         30

                  Figure 4A. Impoundment 1 Water Flushing Sampling               31

                  Figure 4B. Impoundment 2 Water Flushing Sampling               32

                  Figure 5. Pathways and Products of DDT Metabolism in Some      33
                      Living Organisms
                  Figure 6. Pathways of Metabolism of Lindane and Related        34
                      Compounds
                  Figure 7. Metabolic Conversions of Aldrin, Dieldrin, and       35
                      Photodieldrin











             Summary - Pesticide Residue Occurrence and Distribution in the Mosquito
                        Control Impoundments

                    This project was to determine the occurrence and distribution of
             chlorinated pesticides in the St. Lucie County mosquito control impoundments.
             A total of 18 impoundments located on the barrier islands between the Indian
             River lagoon and Atlantic Ocean on east coast of Florida were screened to
             determine the presence or absence of pesticides.       Two random core sediment
             samples and two core hole water samples from each impoundment were collected.
             Each core sample was approximately six feet in depth and was Subdivided into
             three sections (top, middle, and bottom layer) for analysis. The results show
             that 10 sediment samples from eight impoundments were found to contain p,pl-DDE
             (a degradation compound of DDT). The detected concentration ranged from 1.87
             ng/g at impoundment 10A (site 2, top layer) to 31.2 ng/g at impoundment 23
             (site 1, top layer).     Impoundments 1, 2, 5, 10A, 16A, 18, 19B and 23 were
             detected at least once with p,p'-DDE. These impoundments are located on the
             central and north sections of the study area.
                    Six sediment samples from three impoundments contained dieldrin ranging
             from 2.54 ng/g at impoundment 3 (site 1, middle layer) to 43.2 ng/g at
             impoundment 3 (site 1, top layer). Dieldrin was mostly found in impoundments
             2, 3, and 17A, which are located on the central section of the study area.
             Lindane (y-BHC) was found in most of the impoundments located on both north and
             south ends of the study area. Impoundments 5, 7, 8, 9, 10A, 12, 16A, 17A, 18,
             19B, 23, and 24 were found to have lindane contamination.           The detected
             concentration ranged from 0.85 ng/g at impoundment 24 (site 1, top layer) to
             34.4 ng/g at impoundment 12 (site 2, top layer). The lindane concentration was
             generally higher at the top layer and then gradually reduced to bottom samples.
             The core water samples collected from each impoundment were also analyzed. The
             results show that pesticide residues were non-detectable (1 0.01 Pg/1) in all
             of the water analyzed.
                    Impoundment I (unmanaged impoundment) and Impoundment 2 (managed
             impoundment) were selected for detail water and sediment analysis to determine
             the extent of pesticide contamination. Both water and top layer of sediment
             samples were collected from 10 to 11 sites in both impoundments, respectively.
             Three sampling sites [I1/T4 (D), II/T7 (G), and I1/S1] in impoundment 1
             contained p,pl-DDE.    The concentration ranged between 7.54 ng/g at I1/T7 to
             2.41 ng/g at H/T4. Results show that most of p,pl-DDE contamination occurred
             at the north section of impoundment 1. Lindane was found in four sites from
             impoundment 2 [12/Tl/S2 (B), 12/Tl/S3 (C), 12/T2/S2 (E), 12/T3/S3 (I)]. The
             concentration ranged from 2.80 ng/g at T3/S3 (I) to 5.92 ng/g at T1/S2 (B).
             Dieldrin concentration of 15.6 ng/g and 26.9 ng/g were also detected in the
             impoundment 2 site T2/S2 (E) and T3/S3 (1), respectively.      Only one site at
             T1/S3 (C) in impoundment 2 contained 2.29 ng/g p,pl-DDE concentration. A total
             of 22 water and sediment samples from both impoundments were analyzed.
             Pesticide residues were non-detectable (S 0.01 pg/1) in all of water samples
             collected.
                    Water exchange between impoundments and the estuary was examined in this
             study. Water samples from impoundments 1 and 2 were collected (1) at the end
             of the open session, (2) during mid-closure period, and (3) at the end of the
             closure period.     Samples taken from (a) 50 feet from culvert into the
             impoundments, (b) at culvert on the riverside, and (c) 100 feet 'into the river,
             were analyzed.    A total of 88 water samples were analyzed.       The pesticide

                                                     3












           residues in all of the water samples were non-detectable.
                 The study concludes that lindane, dieldrin and p,p'-DDE were found in
           most of the impoundments. They were mostly concentrated on the top layer of
           sediment. Pesticide compounds have a low solubility in water and once released
           to the aqueous environment, have a tendency to be adsorbed by particulate
           matter.   This particulate matter gradually sinks to the bottom.       Pesticides
           normally do not remain long in the water.     The soil or mud bottom acts as a
           sink source for pesticides. Organic muck concentrated mostly on the top layer
           of sediments have a strong tendency to adsorb these pesticide compounds. The
           more organic matter in soil, the longer the pesticides can persist in it.
           Microbial degradation of these pesticides (DDE, dieldrin, and lindane) in the
           soil play an important role to breakdown these compounds. However, there was
           no strong evidence that they could completely break them down. Enhancement of
           microbial activity in the impoundment could possibly stimulate and increase the
           degradation rates of these contaminants in the impoundment.

           Chlorinated Pesticide Residue Analysi

                  Water samples were centrifuged at 8000 G for 25 min at 10 OC to separate
           suspended solids from the water. A 900 ml water sample was extracted with 60
           ml of methylene chloride three times. The extract was then passed through a
           Na2SO and florisil column for clean-up procedures. Activated copper was added
           to rtmove sulfur compounds prior to gas chromatographic analysis.             The
           analytical procedure is presented in Table 1.
                  EPA method 3540 (18) was used to extract sediment samples for chlorinated
           pesticide analysis. A dried sediment sample (100 g) was soxhlet extracted with
 is        300 ml hexane/acetone (1:1) mixture for 24 hours. The extract was then passed
           through Na SO and florisil columns.    Copper was also added to remove sulfur.
           The analytG) procedure for sediment samples is presented in Table 2.
                  A 30 m X 0.25 mm DB-5 fused silica column equipped with an electron
           capture detector in a Perkin Elmer Sigma 3B gas chromatograph was used to
           analyze water samples. Argon/methane (6 ml/min) was used as carrier gas. The
           temperature program was set at 180 OC for 6 min. to 280 OC at a rate of 3
           OC/min. The gas chromatograph operating conditions and calibrations curves for
           each chlorinated compound are included in Table 3.       The minimum detectable
           concentration for each compound is 0.01 pg/l. The mean recovery (84% to 99%)
           and relative deviation (7% to 16%) for water samples for each compound are
           shown in Table 4.    A gas chromatograph/mass spectrometer (A DB-5 capillary
           column equipped with Varian GC 3400 and Finnigan ITDS 806A) was used to analyze
           sediment samples. The GUMS was also used to confirm Water sample analysis.
           The operating conditions and retention times for each compound are present in
           Table 5.   The minimum detectable concentration for sediment samples ranged
           between 0.17 ng/g for a-BHC to 0.49 ng/g for endrin.         Twelve chlorinated
           pesticides were analyzed for both water and sediment samples. The accuracy and
           precision of sediment analysis for chlorinated pesticides shown in Table 6
           ranged between 77% to 98% and 6% to 13%, respectively. The analytical standard
           for each compound was obtained from Supelco, Inc. For each set of samples, a
           method blank, a spiked sample and the unknown samples were performed. Prior
           to each unknown sample analysis, dibutyl chlorendate was spiked as a surrogate
           standard to monitor sample extraction efficiency.

           Results and Discussion


                                                   4










                    Two random sampling sites for each impoundment were selected for sampling
              both core sediment and core water samples. Each core sample was approximately
              6 ft in depth and was subdivided into three sections (top, middle, and bottom)
              for analysis. During the screening phase, a, total of 34 water samples and 92
              sediment samples were analyzed to screen for the presence and distribution of
              pesticides in 18 impoundments. Pesticide residues were non-detectable (S 0.01
              Vg/g) in all the 34 water samples analyzed.    The analytical results of each
              water sample analysis are included in addendum Table 1. Dieldrin, p,pl-DDE,
              and lindane were detected in some of the sediment samples collected.  A s umma ry
              of the detected compounds in the sediment samples at each impoundment are shown
              in Table 7.    Figure 1 shows the location and distribution of        pesticide
              occurrence in   the 18 impoundments.      The exact sampling site     for each
              impoundment and concentration of detected compounds in each layer of sediment
              samples are presented in Figure 2A to 2L.
                   A total of ten sediment samples from eight impoundments were      found to
              contain p,pl-DDE. The concentration ranged between 31.2 ng/g at impoundment
              23 (site 1, top layer) to 1.87 ng/g at impoundment 10A (site 2, top layer).
              Figure 1 shows that the p,pl-DDE occurred mostly in the top soil of the north
              part of the mosquito impoundments. Impoundments 1, 2, 5, 10A, 16A, 18, 19B,
              and 23 were detected with DDE at least once during the study period. A total
              of six sediment samples from three impoundments (2, 3, 17) contained dieldrin.
              Top layer sediment samples of both impoundments 2 and 3 had a dieldrin
              concentration of 34.0 and 43.2 ng/g, respectively.     Figure 1 shows dieldrin
              contamination mostly occurred in the middle section of the study area (i.e.
              Impoundment 2, 3, and 17 were detected once with dieldrin). Lindane (y-BHC)
              was another pesticide detected in the sediment. A total of 33 sediment samples
              from 11 impoundments were found to contain lindane.           The compound was
              distributed mostly at the south and north end of the study area (impoundments
              7 to 12 and 16A to 24) as shown in Figure 1 and Figure 2. Lindane was detected
              in the top and middle  or bottom core samples at impoundment 8, 12, 17A, 19A,
              19B, and 24. The concentration of each sampling site is shown in Figure 2.
              The concentration was generally higher at the top layer and then gradually
              reduced to bottom samples. The highest concentration detected was 34.4 ng/g
              lindane at impoundment 12 (site 2, top layer) and reduced to 9.4 ng/g at the
              bottom layer in the same site. The analytical results of each sediment sample
              analysis are shown in Appendix B Tables 2-19.
                    Impoundments 1 and 2 were selected for detail analysis to determine the
              extent and distribution of pesticide contamination. Transect sampling for both
              water and sediment in both impoundments was performed. Ten and eleven sampling
              sites approximately 15001 and 600' apart 'in both impoundments 1 and 2 were
              chosen as shown in Figures 3A and 3B. Onl, top layer sediment and core hole
              water samples frbm each site were collected. A total of 22 water and sediments
              samples each were analyzed. The analytical results of each water and sediment
              analysis were included in Appendix B Tables 20 - 23. The detected pesticides
              in the transect sediment samples are summarized in Table 8 and Figures 3A and
              3B.  Only p,p'-DDE was detected in the two sites from impoundment 1.          The
              concentration was 2.41 and 7.54 ng/g at transect site D and G, respectively.
              Both samples plus the sample from the random sampling site (Il/Sl) indicate
              that DDE contamination mostly occurred at the north section of impoundment I
              (Figure 3A).   Lindane was found in 4 samples (B, C, E, and I) collected at
              impoundment 2. The concentration ranged from 2.80 ng/g at transect 3 (site I)
              to 5.92 ng/g at transect 1 (site B). Dieldrin was found in two samples from

                                                     5










             impoundment 2.   A concentration of 15.6 ng/g and 26.9 ng/g was detected at
             transect 2 (site E) and transect 3 (site I), respectively.
                   Water exchanging between impoundments and the estuary was also studied.
             Water sampl es i n impoundments 1 and 2 were col 1 ected (1) at the end of the open
             session (March 8, 1990 for impoundment I and April 17, 1990 for impoundment 2),
             (2) Mid-closure period - impoundment 2 only on July 12, 1990, and (3) the end
             of the closure period on October 8, 1990. Samples were taken from (1) 50 ft
             from culvert into the marsh, (2) at culvert on the river side, and (3) 100 ft
             into the river. Two culverts were selected for each impoundment in this study.
             The sampling sites for both impoundments 1 and 2 are shown in Figure 4A and 4B.
             A total of 88 water samples were analyzed to study the water quality between
             the impoundments and the estuary.     The pesticide concentration in all of 88
             water samples analyzed was non-detectable.       The analytical results of each
             water analysis run are shown in Appendix B Tables 24 - 29.
                   The  study   concludes   that   lindane,   dieldrin,   and   p,p'-DDE    were
             concentrated on the top layer of the core sample.        Analysis of impoundment
             water and core hole water did not detect any chlorinated pesticides. Pesticide
             compounds once released to the aqueous environment, have a tendency to be
             adsorbed by particulate matter and gradually sink to the bottom. Pesticides
             normally do not remain long in the water and the soil or mud bottom act as a
             sink source for pesticides. There are many factors that could determine the
             persistence and degradation of pesticides on the soil or sediment environment.
             Pesticides can be adsorbed by soil constituents, leached by impoundments or
             rain water, taken up by plants or animals, broken down by microbial activities,
             photooxidized by natural sunlight.       The soil type greatly influences the
             adsorption of insecticides.      Normally, pesticides are largely adsorbed in
             organic muck and followed by clay loam, sandy loam, silty clay, coarse silt,
             light sandy clay loam, and silty clay loam (19).         The ways in which soil
             structure affects the persistence of pesticides is closely linked with organic
             matter, clay content, and hydrogen ion concentration. It seems that the more
             organic matter in a soil, the longer an insecticide persists in it.
                   The soil type influences not only the persistence and activity of
             insecticide in soil, but also the rate at which they are converted or degraded
             into other compounds. Micro-organisms in different types of soil could play
             an important role in breaking down the pesticides. However, several studies
             have shown little evidence that they can completely break them down. The major
             microbial metabolic steps are reductive dechlorination, dehydrochl ori nation and
             the oxidative systems. DDT and lindane can be dehydrochlorinated via microbial
             breakdown to DDE and pentachlorocyclohexene (PCCH).            Dieldrin undergoes
             microbial reaction or other biological oxidation to form photodieldrin. The
             complete degradation pathways for each compound are attached in Figures 5 to
             7 for DDT, dieldin, and lindane, respectively. The intermediate degradation
             compounds and the persistence or disappearance rate can be varied with
             different types of environmental conditions. The persistence and degradation
             rates of insecticides in the St. Lucie County mosquito impoundments has not
             been studied. This project only focuses on the occurrence and distribution of
             chlorinated pesticides in the impoundments.






                                                      6













                           Table 1. ANALYTICAL PROCEDURE'S FOR WATER SAMPLES




                          Water sample centrifuged at 800OG for 25 min at 10 7C.
                                                    F
                                  900 ml supernant extracted with 60 ml
                                   Methylene Chloride for three times.


                         Dry the extract by passing it through a drying column
                           containing 10cm sodium sulfate collect with K-D.


                        Evaporate to 0.1 ml and reconstitute with 10 ml Hex@ne.


                                    FA-dd copper for Sulfur removal.


                       Add 20 g of activated Florisil to a 20mm I.D. column with
                          2 cm sodium sulfate on t r     nse with 60 ml hexane.
                          Charge 10 ml sample onto column ana-rinse K-D


                 Elute column with 150 ml of 15% Et -yl Ether in Hexane collect in K-D.1



                    lConcentrate to 0.1 ml and analyze with GC/MS for pesti












                                                    7












                       Table 2. ANALYTICAL PROCEDURES FOR SEDIMENT SAMPLES




                              Dry sediment in oven at 100 C for 1 hrj


                                Soxhlet extract 100 g sediment with
                            1300 ml Hexane/Aceto e (1:1) for 24 hrs.]

                       Dry the extract by passing it through a drying column
                          containing 10cm sodium  ulfate collect with K-D.
                                                4
                      Evaporate to 0.1 ml and reconstitute with 10 ml Hexane.
                                                r
                                 FA-ddcopper for sulfur removal.


                     Add 20 g of activated Florisil to a 20mm I.D. column with
                        2 cm sodium sulfate on top Rinse with 60 ml hexane.


                       Charge 10 ml sample onto column and rinse K-D twice.


               Elute column with 150 ml of 15% Ethyl Ether in Hexane collect in-@--Dj.



                   concentrate to 0.1 ml and analyze with GC/MS for pesticideW
                                                I  .


                                                 8
  0











                Table 3. GAS CHROMATOGRAPH OPERATING CONDITIONS AND CALIBRATION CURVES



                   G.C. Model:    Perkins Elmer Sigma 3B
                   Column:        30m x 0.53 mm Id. J&W DB-5 P/N 125-5032
                   Carrier:       Ar-CH 4 6 mt/min.
                   Oven:          1800C for 6 min. to 2800C at rate of'30C/min.
                   Detector:      Electron capture at 3300C
                                  Make-up gas 30 mt/min.


                                    CALIBRATION       CALIBRATION CURVES (5 pt.)           CORRELATION
              COMPOUNDS             RANGE (nq)            Y=area X= amt.(ng)               COEFFICIENT

              a-BHC                    0.25-2.5             Y=1.471X+0.0466                  0.998

              P-BHC                    0.25-2.5             Y=0.514X+0.00388                 0.999

              y-BHC                    0.25-2.5             Y=1.310X+0.00981                 0.999

              6-BHC                    0.25-2.5             Y=1..308X+0.0463                 0.999

              Heptachlor               0.25-2.5             Y=]..1155X-0.0324                0.999

              Aldrin                   0.25-2.5             Y=]..316X-0.0438                 0.999

              Heptachlor   Epoxide     0.25-2.5             Y=1.178X+0.2O9                   0.999

              P-PI-DDE                 0.5-5.0              Y=0.877X+0.208                   0.999

              Dieldrin                 0.5-5.0              Y=111.128OX-0.0333               0.999

              Endrin                   0.5-5.0              Y=0.741X-0.0150                  0.998

              p.pl-DDD                 1.5-9.0              Y=0779X+0.205                    0.999

              p-p'-DDT                 1.5-9.0              Y=:L.344X-0.164                  0.999


              SURROGATE
              STANDARD

              Dibutyl Chlorendate      (5.40)               Y=0.480X+1.359                   0.994












                                                    9










                           Table 4. Quality Control for Water Sample Analysis



                                              MEAN              RELATIVE
            COMPOUNDS                     RECOVERY %             DEVIATION             MINIMUM
                                            X ï¿½ S.D                M               DETECTABLE-(nq/q)


            (I-BHC                        92.8 ï¿½ 12.5              13.5                  0.01

            0-BHC                         89.1 ï¿½ 13.8              15.5                  0.02

            y-BHC                         97.4  ï¿½ 13.7             14.1                  0.01

            6-BHC                         83.9  ï¿½ 13.3             15.9                  0.01

            Heptachlor                    95.3  ï¿½ 11.5             12.1                  0.01

            Aldrin                        98.9  ï¿½ 13.1             13.2                  0.01

            Heptachlor    Epoxide         95.5  ï¿½ 12.4             13.0                  0.01

            P-PI-DDE                      96.5  ï¿½ 11.7             12.1                  0.01

            Dieldrin                      94.8  ï¿½ 11.6             12.2                  0.01

            Endrin                        85.2  ï¿½ 11.5             -13.5                 0.01

            p-P'-DDD                      89.9  ï¿½ 6.08             6.76                  0.01

            p-P'-DDT                      94.1  ï¿½ 8.95             9.51                  0.01


            Surrogate Standard

            Dibutyl                       97.6 ï¿½ 9.44              9.67                  0.05
            Chlorendate

            *Minimum detectable concentration (jig/t) basis on 900 ml water             sample.

              (5 X G.C. noise)        x (ini.amt.) x (final ext.)            x    1      x      1
              std.inj. pk area                             (inj. vol.)          (sample     (recovery)
                                                                                 size)












                                                       10











                        Table 5. GAS CHROMATOGRAPH/MASS SPECTROMETER (ION TRAP DETECTOR)
                                                  OPERATING CONDITIONS


              Model:        Varian GC 3400 & Finnigan ITD 801)
              Column:       DB-5, 30m x 0.25m ID
              Carrier:      Helium (25 cm/sec) Head pressure         11 psi
              Oven:         800C for 1 min to 2250C at 80C/min and to 2800C at 30C/min
              Detector:     Ion trap with open split interface


                                    RETENTION           BASE                SCAN          SENSITIVITY
              COMPOUNDS             TIME (MIN.)          PEAK                 NO.              (ng)


              a-BHC                    20.00             181                1218               0.5

              P-BHC                    20.50             181                1269               0.5

              y-BHC                    21.04             181                1282               0.5

              S-BHC                    21.49             181                1329               0.5

              Heptachlor               23.33             272                1412               0.5

              Aldrin                   24.51             263                1419               0.5

              Heptachlor  Epoxide      26.24             355                1583               0.5

              p-p'-DDE                 28.47             246                1727               1.00

              Dieldrin                 29.06             263                1745               1.00


              Endrin                   30.08             263                1807               1.00

              p-p'-DDD                 30.48             235                1846               1.00

              p-p'-DDT                 32.42             235                1953               3.00


              Surrogate
              Standard


              Dibutyl
              Chlorendate              36.22             388                2181               0.50












                        Table 6. QUALITY CONTROL FOR SEDIMENT SAMPLE ANALYSIS



                                        MEAN             RELATIVE
            COMPOUNDS               RECOVERY %           DEVIATION            MINIMUM
                                      X   S.D              M              DETECTABLE (nq/q)

            a-BHC                   84.3    11.1           13.2               0.17

            P-BHC                   98.3    6.35           6.46               0.19

            y-BHC                   85.1    5.69           6.69               0.18

            &-BHC                   89.3    2.45           2.74               0.21

            Heptachlor              85.8    8.88           10.3               0.46

            Aldrin                  86.3    10.0           11.6             -0.18

            Heptachlor  Epoxide     80.2    6.56           8.18               0.24

            P'PI-DDE                96.8    9.63           9.95               0.24

            Dieldrin                76.5    5.48           7.16               0.32


            Endrin                  81.1    5.71           7.04               0.49

            p,pl-DDD                93.2    5.61           6.02               0.29

            PIP'-DDT                88.8    9.35           10.5               0.40




            Note:

            I. @: Mean value of a set of n = 5 samples.
            2. S.D.: Standard deviation.
            3. Minimum Detectable: Corrected with recovery efficiency for each
                 compound, basis on 1OOg sample size.








                                                      12












                                    Table 7. SUMMARY OF DETECTED COMPOUNDS IN THE SEDIMENT
                                                        SAMPLES AT EACH IMPOUNDMENT (ng/g)

                              Sampling               PIP'-DDE             Di el dri n            Lindane (y-BHC)
                              Location                (nq/q)                (nqlq)                 (nq/2)

                              I1/S1/O1                  2.65                 N. D.                  N.D.

                              Il/Sl/02                  3.05                 N. D.                  N.D.

                              12/S1/O1                  N.D.              34..0ï¿½2.36                N.D.

                              12/S2/01                  17.0                 N. D.                  N.D.

                              13/S1/O1                  N.D.              43..2ï¿½2.11                N.D.

                              13/S1/02                  N.D.                 2.54                   N.D.

                              13/S2/01                  N.D.                 6.31                   N.D.

                              13/S2/02                  N.D.                 5.52                   N.D.

                              15/S1/O1                  N.D.                 14. D.                 2.28

                              15/S1/02                  N.D.                 N. D.                  2.83

                              15/S2/01                  14.8                 11. D.                 N.D.

                              17/S1/O1                  N.D.                 N.D.                   4.45

                              171S2/01                  N.D.                 N.D.                   4.84

                              17/S2/02                  N.D.                 N.D.                   4.06

                              18B+C/S2/01            -N. D.                  N.D.

                              18B+C/S2/O2            -N. D.                  N.D.                   2.30

                              19/S1/O1                  N.D.                 N.D.                2.99ï¿½0.13

                              19/S2/O1                  N.D.                 N.D.                   3.87

                              I1OA/S1/O1             -N. D.                  N.D.                   1.58

                              I10A/S2/01             -1.87                   N.D.                   4.94

                              112/SI/01                 N.D.                 N.D.                8.95ï¿½0.29

                              I12/S1/02                 N.D.                 N.D.                   1.66

                                                                              13














                                                  Table 7. cont.

                      Sampling           PIP'-DDE         Dieldrin           Lindane (y-BHC)
                      Location*            (nq/q)            (nq/q)            (ng/g)

                      I12/Sl/03             N.D.             N.D.               6.03

                      I12/S2/01             N.D.             N.D.               34.4

                      I12/S2/02             N.D.             N.D.               4.46

                      I12/S2/03             N.D.             N.D.               9.40

                      I16A/S1/O1            0.39             N.D.               5.14

                      I16A/S2/01            N.D.             N.D.               5.37

                      I17A/Sl/01            N.D.             28.1               8.50

                      I17A/Sl/02         -N. D.              N.D.               3.42

                      I17A/S2/01            N.D.             N.D.               7.84

                      I17A/S2/02            N.D.             N.D.               6.79

                      I17A/S2/03            N.D.             N.D.               5.26

                      I18/S2/01             3.83             N.D.               8.08

                      I19A/S1/O1            N.D.             N.D.               3.69

                      I19A/Sl/02            N.D.             N.D.               3.07

                      I19A/S2/01            1.97             N.D.               12.9

                      I19B/SI/01         3.55ï¿½0.87           N.D.             .13.7ï¿½1.30

                      I19B/SI/02            N.D.             N.D.               3.51

                      123/Sl/01             31.2             N.D.               3.35

                      124/Sl/Ol             N.D.             N.D.               0.85

                      124/S2/01             N.D.             N.D.             8.53ï¿½0.70

                      124/S2/02             N.D.             N.D.               5.93

                      124/S2/03             N.D.             N.D.               2.62

                         Impoundment no./   site no./ layer no.

                                                              14












                                     Table 8. SUMMARY TRANSECT SEDIMENT SAMPLING FOR
                                                    IMPOUNDMENTS 1 AND 2



                       Sampling           PIP'-DDE         Dieldrin           Lindane (y-BHC)
                       Location*-          (ng/q)             nq/g)            (nq/q)

                       I1/T4 (D)            2.41              N.D.              N.D.

                       I1/T7 (G)            7.54              N.D.              N.D.

                       12/Tl/S2 (B)         N.D.              N.D.              5.92

                       12/TI/S3 (C)         2.29              N.D.              3.52

                       12/T2/S2 (E)         N.D.              15.6              4.02

                       12/T3/S3 (I)         N.D.              26. 9             2.80




























                          Impoundment Nod site Nod layer No. (Sample identification No.)

                                                              15





                          in each ir-,poui@&Ient at St. Lucie, Florida.
                                                     IMP. 24 (0)
                                                     Imp. 23 (e)

                                                       Imp. 19B      E)
                                                                                    Atlantic
                                          ICD            Imp. 19A                    Ocean
                                                           IMP. 16A (9)
                                                            Imp. 17A (A., a)

                                                             Imp- 18A (o

                                                               Fort Pierce Inlet





                                                                  Imp. 1

                                                                   Imp. 2 (0   A)

                                                                     Imp. 3 (A)
                                                                      IMP. 4


                                                                          Imp. 5


                                                                             Imp. 6
                                                                               Imp. 7 (0)
                                                                                 Imp. 8 (N)

                                                                   CD
                                                                    iEr-           Imp. 9 (a)



          Detected Pesticides in                                                       Imp. 1 OA

           the sediment 6a--Dies


                 DDT-
                 Dieldrin
                 Lindaze                                                                    IM
                                                                                               P. 12


                                                  16







              Figure 2A. Pesticide Distribution i-n the sediment at each Impoundment

                                 (',"-Top Layer.' 11-111liddle Layer, B-Bottom Layer)















                                                           6 A E












                    INDIAN RIVER

                   LAG OON


                                                                             ATLANTIC

                                                                              OCEAN
                                         ZAT'DDE      2.65 ng
                                      111SI 11,DDE    3.05 ng








             s RIM
            CULVERTS


                                                      Il /S2









    DATE:
    SAINT LUCIE COUNTY




                                                   17








              Figure 2B. Pesticide Distribution in the Sediment at each Impoundment
                                (Top-T-op Layer, 141-Middle Layer, B-Bottora Layer)












                  INDIAN                                                   ATLANTIC
                  RIVER                                                    OCEAN
                  LAGCON                                     (T,DDE   17.0 ng/9)
                                                  -121S2

                               7 RIM               12/Sl
                               CULVERTS
                                            2w
                                  (82)
                                                             (T,Dieldrin   34.0 ng/g)
                                                   AIA


































                                                 18









                     Figure 2C. Pesticide Distribution in the Sedir-ent at each Trapoundmient
                                      (T-Top Layer, M- Middle Layer, B- Bottom Layer)














                                                                     (T,Dieldr-in - 6.31 ng/g)
                                                                        Dieldrin - 5.52 ng/g)
                                                          --13/S2



              Inaian River
              lagom          13/Sl-                             Atlantic Ocean
          (T,Dielarin   43.2 ng/g)
          (11,Dieldrip- 2.54 ng/g)


                                       14/Sl
                                                          @14/S2

                                         "W           E





























                                                19











                 Figure 2D. Pesticide Distribution in the Sediment    at each Impoundment
                                (T7-Top Layer, M-Middle Layer, B"Bottom Layer)
















                                                               15  S 2 (T, DDE - 14. 8 ng/g)



                                 14= 13 0 q


                                          I 5,/S 1."                     Atlantic
                 Indian River
                 I-agc)on                           5W 5E                Ocean
                 (T, BHC   2.28 ng/g)
                 (M, BHC   2.83 ng/g)























                                                  20








             Figure 2E. Pesticide Distribution in the Sediment at each Impoundment
                              (.T-Top Layer, M-Middle Layer, B-Bottom Layer)












                                                    16/S2

                                             G E


                                   16/Sl

    Indian River               6 w                                  1301,
   Lagoon
                                                             Atlantic

                                                             Ocean



 0

                                              O--i7/Sl (-J,BHC      4.45 ng/g)

                             7vv            7a

                    17/S2




                        (T,BHC - 4.84 ng/g)
                        (M,BHC - 4.o6 ng/g)















                                              21











                 Figure 2F. Pesticide Distribution in the Sediment at each Impoundment
                                  (T-Top Layer, M-Middle Layer, B- Bottom Layer)




















                                                                        Atlantic
         18/Sl                                        SA                Ooean
                                        Lfj



    Indian River          8
    I-agoon
                 18/S2                          E:>


                 (T,BHC - 3.55 ng1g)
                (M,BHC - 2.30 ng/g)

















                                            22








              Figure 20. Pesticide Distribution in the Sediment at each Impoundment
                               (T-Top Layer, M-Middle Layer, B-Bottom Layer)










                                                                                41


                                                          9 IS I (T, BHC 2. 99 ng/g)




              (T,BHC   3.87 ng1g) 19 IS 2
               Indian River                                     Atlantic
               Lagoon                                           ocean
























                                                23





                 Figure 2H. Pesticide Distribution in the Sediment at each Impoundment
                                     (T-Top Layer, M-Middle Layer, B-Bottom Layer)










                             6 RIM
                        CULVERTS
                             (1110A)




          INDIAN RIVER                          11OA/S2*                     4-.94 ng/g)
          LAGOON                                                   (T,BHC



                                                                             ATLANTIC

                                                                              OCEAN










                                          IlOA/Sl-                  (TBHC    1.58 ng/g)
                                      SR EACtj

                                                       '110 E3
















                  DATE:    2-2S-87
                   SAINT LUCIE COUNTY






                                                    24











              Figure 21. Pesticide DistriDutlon In the Sedimerit at each Impoundment
                                 (T-Top Layer, 14-Middle Layer, B-Bottom)













                                                                                ATLAt4T'C-







              (T BHC       95,-.n@/fg)           Its        'fjA
              (M'BHC - 1:66 ng/g)
              (B)'BRC  6.03 ng/u)            112/Sl



                                               /A (seat f)')                  I12/S2
                                                                pi              (T,BHC   32.4 ng/g)
                                                                                (M,BIIC  4.46 n,l,-)
                                                                                                0
                                                                                (B"Bllc  9.40 lig/6)







                                                   25






                    Figure 2J. Pesticide Distribution in the Sediment at each Impoundment
                                     (T-Top Layer, M-Middle Layer, B-Bottom Layer)




             0
                                                                                 (T,DDE - 0.39 ng/g)
                                                                                 (T.BHC - 5.14 ng/g)




                   00


             Indian
          0
             PL2 ver     C7
             lagom
         O@:)                   '1 6.4%
                                                                              (T,Dieldrin-28.lng/g)
  T,BHC   5.37 ngjg)        -I16A/S                                          -(T,BHC   8.50 ng/g)
                                                   I17A/Sl                   I (B,BHC  3.4:9 ng1g)

                                                    7^


                                                            I17A/S2
                                                                                 Atlantic
                                                                                 Ocean


                          ISE3














                                                  Is^



                                  118A/S2
       (T,DDE -  3.83 nglg)-Z.
       (T,,BHC - 8.08 ng1g)










                                               26





 Tigure.2K. Pesticide Distribution in the Sediment at each
              Impoundment (T-Top Layer, M-Middle Layer, B-Bottom
                            Layer)















                                                                    Atlantic Ocean
      DDE - 3.55 ng1g)
      ,BHC - 13.7 ng/g)
   .i,BHC - 3.51 ng/g)
      Indian River               I19B/Sl
      Lagoon
                             0'    19 Ea
                                 I19B/S2








   (T, DDE - 1.97 ng/g)
  @M,BHC   - 12.9 ng/g)
                  119A/S2


                           8 RIM
                           CULVERTS              COVE
                           (919A)

                                    0

                                         119A/S1



      DATE:  1-19-88
      SAINT LUCIE COUNTY              (T,BHC - 3.69 ng/g)
                                      (M,BHC - 3.07 ng1g)










                                                27






          Figure 2L. Pesticide Distribution in the Sediment at each Ikpoundment'
                            (T-Top Layer, M-Middle Layer, B-Bottom Layer)




                                                                            (T,BHC  - 8.53 ng/g)
                                                                           4 M,BHC  - 5.93 ng/g)
                                                                            (B,BHC  - 2.62 ng/g)




                                                  124/S2

                                                Z4

                (T,DDE-0.85 ng/g)     124/Sl


                                                  123/81                    Atlantic
                                              (T,DDE - 31.2 ng1g)          0:-ean
                                              (T'.IBHC - 3.35 n9/9)






       Indian River Lagoon                               123/S2



















                                                 28



                      Figure 3A. Transect Sediment Sanpllno at Impoundrient I




         0                   1309                                                        Noilh


              Scale In Feet
                                              TS
                                           (E)          Osl

                                                               (T,!)DE-2.65ng/q_)
   Indian Rver Lagoon                                          (M,D9E-3.05nq/q)


                               T4 (T,DDE-2.41ng/g)                      (F)
                                                                         W T6
                            (D)                              T7           (T,rDE-7.' 4ng/p)
                                                         (G)




                                                                            AlA



                                 T3

                              (C)




                                                                Ts

                             T2





                                 Tl




           Key

         Pesticide Core

        Non-Pesticide Core

                                                  29





                  Figure 3B. Transect Sediment Sampling at Impoundnent 2





         0                   1309
                                                                                 North

              Scale In Feet








                 Indian River Lagoon

                                                     S2
                                                            AIA
                                             T3/3 (H)    (G)
                                                   7312 T3/1
                                                    M
                                           M        (E)  (0)
                                          7213    TM    T2J1
                                                                    (B, BHC-5.92no/g)
                                                                    (C' DDE-2.29nq/g)
                                                                    (C, BHC-3-52ng/g)
                                            (C)     (B)  (A)        (E, Dieldrin-15.6ng/9)
                                                                               2-nq/9)
                                            Ti/3  T1/2   TIM        (E, BHC-4.0
                                            0                       (1, Dieldrin-26.9ng/9)
                                                                    (1, BHC-2.80nq/g)












                                            Pesticide Core

                                            Non-Pesticide Core





                                                  30






                    Figure 4A. Impoundment I 'later Flushing Sampling





                                1 AR1 00                                              Norlh

                        1BR100     1ACR

                              1 BCR
                                          0 1 AM50

                                     0 1 BM50





















                                    Indian
                                    River
                                   Lagoon                     Impoundment I






                                                               Culverts



                                            Dike










                                               31






                         Figure 4B. Impoundment 2 1.1ater Flushing Samp] ing





                                                                          Indian
                                                                          River              Al A
                                                                         Lagoon
                                                                                            CV

                                                                     Culverts
                        Norlh



                                                                        Dike



















                                  2BM50
                      2BCR                            2AM50
                      0    0                             0
                  2B R100
                                                   CR


                                                    0
                                              2AR1 00





















                                                  '@2









                                     DBP. DSH, DDE                                             DDT                           Pl(v) m
                                                                                           -CH CCI,                          P(V) M
                                                                m         (v)                              P(V) (i)                            PI V)
                                         DICOFOL                                                           R(v) (i)-.Pl(v)                  m
                                         C(OH)CCI,                                                         RV). m
                                                                                                           R, man                      R(v) (i) man
                                                m
                                                                                                DDD-                       DDM R(v)
                                                                                                                         -CH,

                                           FIN 152                                                         P40
                                         C(OH)CHC12                                                        R(v)
                                                                                                           Pj(V)
                                                                                                           m


                                          DDNS                                            -DDMU -4                                             DDE
                                          CHCH,                                              :::(,=CHCI



                                                                                                                  R(0
                                                                                                                                           +H, 0
                                                                                                                                            via
                                                                                              DDMS                                    H     si
                                                                                                                                     "C-C,
                                                                                           .IeCH-CH,CJ                                         OH

                                                                                                           Riv)

                                                                                                           ni

                                                                                              DDNU



                                                                                                           Rt%)
                                                                                              D Oil        -R-"-* 0:CHCH-O)                                DDA       RM
                                                                                                                                                                       Ito
                                                                                           "@CHCH, OH                                                   CHCOOH 131411
                                                                                                                                               rnZ           I
                                                                                                                                       DBH phv)
                                                                                                                                        HOH R(%)




                                                                                                           pl(%) DBP                UNKNOWN ---I@ GLUCOSIDE
                                                                                                           14%) --('=O                     lol,                  ho

                                   FICURE 5. Pathways and products of DDT metabolim in sorne livinp organisms. I a insects; m a mJclootPniSMs;F=
                                   pigeon. pil   plants. R    tat; i  in vitro; v c in vivo    (20)
                                                                                                           I
                                                                                                  D
                                                                                                                             P'(v)  m
                                                                                                                             P(v) (i)l(v 0 (i) PI(
                                                                                                           )-Pl(v)                          m

                                                                                                           Man                         R v) (i)




























































                                                                                             33





























                                                                                        Cl
                C1 RM                H(v)(i)-.T(v);Io(v)'.G(vX0
                      4                                                            C1         Cl
                                                                                   CI(DCI
         CI                                                                             SR                                   3*@4--.2.S-
                SR            Cl         Cl                                                               7    dichloro-     dichlotophenols
                                              3                                                                benzenes           8
                              Cl         SR
                             -      Cl                                                   C1                              C1
                                                I        Cl      M(?)-. pl. soil. rn CIOCI                                      19
                          GSH
                0"           (_HCO             C1        Cl                        Cl          Cl
                                           7-PCCH Cl 2                                                                            Cl
                                                                                     -y-HCH I
                                                                                                                           20            R
                                                                                         Cl
           2.4-dichloro-                 a Ci            a             Cl            JOC'                    2 1 R    o.m. or p-SCH'2 CH(NHAc)COOH,
           thiophcnol                     Cl Cl          C1            Ci           C          CI                      22      -SCH,CH(NH,)COOH.
           Plu, 5 position                                  Cl[O                                                       23      _O)i
           i%omcm                                                                     9 Cl HN)
                                         10                      Cl
                 5                      \ I                       I                          Ci   ri        C1            Cl
                                                   Cl             Cl              /(-,(0               JOCI Cl Ca
                                                                                                                                C)
                              Cl(OCI C'jOCl Cl(3C'                                     12 C,           13 C1                 "(v)   14
                                    Ci                                                     Ra(v*w          HM       R, @()@
                                                                                                                 24        ittrachlorophcnols
                                                             P,(V,



                                                                                                                OH
                isomeric                           Cl                                       OH                        CI        f.IUCuronides,
                trichlorophenyl       Ra      (10                     RM. Ra(v)          [OC' + (.1                         __a@ ethereal
                MerC2ptUTiC acids                        C1                                       CI                            sulfates
                      16
                                                0                                                                -1
                                                              15                      17                  18 L
                    FIGURE .6. hthw.ys (some speculative) of metabolism of Iindane and related compounds. G - pass grub, H - houseflY;
                   10 c locust,, U @ mammal; m -microoTpnisms;pl w plants; Ra @ rabbit; R = rat-.1 - catilt lick; i =in vitTo;v -in vivo; in
                    structure 4. -SR   glutathione for H,T, lo and G; mefcapturic acid for the rat. (20)
                  \G (@H
                             _HC I

























































                                                                           34



































                                                                                                                                                  RIV); MWv)
                           C1 C1    Ct                                           C1 C1    C'                              t       ON               god
                             C1                 0                                                                    9                                    @r
                                    C                                mo(v)         C.                                .0   @'5-                4-Yo
                                        4                               10         C-@, 5 @ph.,.d 10drin                      6
                                                                                                                  R(Vwi)                     PH-)
                                                                                            Uv.                 Ra(v K it
                                                                                            environment       St 0: PH 1)    pit it       m (711
                                                                                            in              1(*)@ m
                            cl   CI        &           n   C1                     C1 (I  C1                  M
                           CI     0           0        C1   a            0 4        C1                0  4 biotic a                                cis-diot
                                                                                                            abioti,:2' 4VALDRIN
                                      3   H    441--   C1               2      ON*        (I
                                                                                    C' VIELDRIN          environment
                                                                                                %
                                 OH*      C1  C1                           OH*                    %
                                                                                    mWv)
                                                                                   3nt 'I
                                          CI    C1          0           R4.Wij  Rh.m(v)    I            %
                                                                       St v)                                                      CI
                                          CI                                                                                           C,
                                                                                  C1                                Y@! ON        C,
                                                                                                           12       m
                                                                                                       0
                                                                                 C,     CI                    carboxylic          cl@
                                                                                                  CH                                      9
                                                                   f    0
                                                             to X                        H       M                       14
                                                                 M ON
                                        0                                                13
                                                         11 Flucuron'dc.Rio
                          "GURE 7 - Mt-bo6bc conversions of aldtin, dieldrin and photodieldrin. H = housefly; I = other insects; m
                          microorganisms-. mi = mice; mo,       mosquito. Pi     pig; p] z: plants, R = rat; Ra = rabbit; Rh.m     Rhesus monkey; S       sheep;
                               in vitro*, V = in vivo. 20.)
                                                                                                      cldnn

                                                                                                                It                           pk@)


                                    @3H       C,










                                                                                      35










            Bibliography

            1. Grzenda, A.R. A Five-year Statistical Survey of Cotton Insecticides Usage in
                   a Large Alabama Watershed. J. Georgia Entomol. Soc. 1:1-11, 1966.
            2. Grzenda, A.R., G.J. Lauer, and H.P. Nicholson. Insecticide Contamination in
                   a Farm Pond. Part II. Biological Effects. Trans. Amer. Fish. Soc. 91:217-
                   222, 1962.
            3. Grzenda, A.R., H.P. Nicholson, J.I. Teasley and J.H. Patric. DDT Residues in
                   Mountain Stream Water as Influenced by Treatment Practices. J. Econ.
                   Entomol. 57:615-618, 1964.
            4. Grzenda, A.R., and H.P. Nicholson. The Distribution and Magnitude of
                   Insecticide Residues Among Various Components of a Stream System. Univ. of
                   North Carolina. Proc. S. Water Resour. Pollut. Contr. Conf.,il4:165-174,
                   1965.
            5. Lauer, G.J., H.P. Nichloson, W.S. Cox and J.I. Teasley. Pesticide
                   Contamination of Surface Water by Sugar Cane Farming in Louisiana. Trans.
                   Amer. Fish. Soc. 95:310-316, 1966.
            6. Nichloson, H.P., A.R. Grzenda, G.J. Lauer, W.S. Cox and J.I. Teasley. Water
                   Pollution by Insecticides in an Agricultural R.iver Basin. I. Occurrence in
                   River and Treated Municipal Water. Limnol. Oceanogr. 9:310-317, 1967.
            7. Nichloson, H.P., A.R. Grzenda, and J.I. Teasley. Water Pollution by
                   Insecticides. A Six and One-half Year Study of a Watershed. Proc. Symp.
                   Agr. Waste Water. 10:132-141, Water Resources Centr, Univ. Calif., Davis,
                   Calif., 1966.
            8. Nichloson, H.P., H.J. Webb, G.J. Lauer, R.E. O'Brien, A.R. Grzenda, and D.W.
                   Shanklin. Insecticide Contamination in a Farm Pond. Part I. Origin and
                   Duration. Trans. Amer. Fish. Soc. 91:213-222. 1966.
            9. Kolipinski, M.C., A.L. Hinger and M.L. Yates. Organochlorine Insecticide
                   Residues in Everglades National Park and Loxahatchee National Wildlife
                   Refuge, Florida. Pesticide Monitoring Journal 5(3):281-288, 1971.
            10. Seba, D.B. and E.F. Corcoran. Surface slicks as concentrations of Pesticides
                   in the marine environment. Pesticide Monitoring Journal 3(3):190-193, 1969.
            11. Wang, T.C. Toxic substance monitoring in the Indian River Lagoon, Florida
                   46(3):286-295, 1983.
            12. Wang, T.C., R.S. Johnson and J.D. Krivan. Residues of Polychlorinated
                   Biphenyls and DDT Residues in Waterand Sediment of the St. Lucie Estuary,
                   Florida, Journal of Pesticide Monitoring 13(2):69-71
            13. Wang, T.C., R.S. Johnson and J.D. Krivan. Reconnaissanc@ of Polychlorinated
                   Biphenyls and DDT Residues in Water and Sediment of the Indian River
                   Lagoon, Florida, 1977-1978. Journal of Pesticide Monitoring 13(4):141-144.
            14. Hunt, E.G., and A.I. Bixchoff. Calif. Fish Game 46:91, 1960.
            15. Hunt, E.G., Scientific Aspects of Pest Control. Nat. Acad. Sci., Nat. Res.
                   Council Pub. No. 1402, 1966.
            16. Keith, J.0. J. Appl. Ecol. 1966., 71, 1966.
            17. Burdick, G.E., E.J. Harris, J.J. Dean, T.M. Walker, J. Skea, and D. Colby.
                   Trans. Amer. Fisheries Soc. 93:127, 1964.
            18. U.S. Environmental Protection Agency. Test Methods for Evaluating Solid
                   Waste, Method 3540, Lab Manual Vol. 1B. SW-846 Nov. 1986.
            19. Edwards, C.A., Pesticide Residues in Soil and Water in Enviornmental
                   Pollution by Pesticides. Plenum Press. 1973.


















































                                SECTION 4


             CONTROLS ON PESTICIDE DISTRIBUTION AND MOBILITY

































                                                                                4






  0-
















                                    Prepared by:

                                Randall W. Parkinson
                           Florida Institute of Technology

                                      Tsen Wang
                        Harbor Branch Oceanographic Institute

                                     James David
  0                       St. Lucie County Mosquito Control











  0













                                   TABLE OF CONTENTS


                                                                     Page

         Controls on Pesticide Distribution and Mobility      ........ 1

               Sediments  .........................................    1


                    Pesticide distribution trends..                    1
                    Controls on pesticide distribution    ...........  1

                Water ..............................................   3

                    Pesticide distribution trends..    :***'****''*'*  3
                    Controls on pesticide distribution    ...........  3

         Concluding Remarks   .....................................    4

         Additional Studies   .....................................    5





                                  FIGURE CAPTIONS               Page

        Figure 1 -  Pesticide presence as a function
                    of weight percent TOM and depth:
                    general survey cores ........................ 6

        Figure 2 -  Ternary diagram illustrating
                    relationship between sediment composition,
                    depth, and pesticide content ................ 7















                  CONTROLS ON PESTICIDE DISTRIBUTION AND MOBILITY



                                      Sediments



         Pesticide Distribution Trends



              Chemical analysis of 53 sediment cores taken in 18 St. Lucie
         County mosquito control impoundments suggests organochlorine
         pesticide distribution is widespread. 89% of the impoundments
         contained pesticides. However, this distribution is very patchy.
         Detailed analysis of Impoundments 1 and 2 suggest the distribution
         of pesticide residue within each impoundment is also patchy. 33% of
         the cores in Impoundment 1 contained pesticide residue and 60% in
         Impoundment 2. In several cases these cores were <150m apart.

              Geographically, gamma BHC (a residual of BHC mixed compounds
         applied in the mid to late 19501s) appears to be concentrated in
         northern and southern areas, while dieldrin (a residual of sandfly
         control experiments conducted in the mid 19501s) is more prevalent
         in the central areas.


              In most cases the concentration of organochlorine compounds,
         if present, decreases with depth (Appendix A2). Pesticides were
         only found in subsurface samples if the overlying surface sample
         contained pesticides.


         Controls on Pesticide Distribution



              The patchy distribution of organochlorine compounds within
         salt marsh sediments of St. Lucie County mosquito control
         impoundments can be attributed to a number of processes including:
         (1) application, (2) post treatment breakdown by microbial or
         microbial-related activity, (3) sunlight, and (4) migration.

              County records are not sufficiently detailed to determine the
         degree to which pesticide application techniques have influenced
         the distribution patterns identified during this study. Post-
         treatment breakdown by microbial activity and sunlight are widely
         recognized as processes which alter the distribution of pesticides
         in marsh substrates. However, this study was not designed to
         investigate post treatment breakdown reaction pathways and
         therefore the degree to which pesticide distribution is controlled
         by these processes remains unevaluated at present.

              The third factor which can influence the distribution of
         pesticides in St. Lucie County mosquito control impoundments is
         migration. All or some of the pesticide residue can potentially














          2

          migrate from a contaminated layer into what were originally
          pristine sediments. This migration can occur in both the vertical
          and horizontal direction. Vertical migration is detectable by
          identifying the contact between sediments that were deposited prior
          to pesticide treatment and those sediments which were at the marsh
          surface when pesticides were being applied. In the case of St.
          Lucie County impoundments, the contact: lies between sediment type
          2 (premarsh) and either sediment type 1 or 4 (marsh). If sediment
          type 2 contains pesticides, - migration has occurred. Lateral
          migration is a more difficult to recognize. It may have occurred if
          pretreatment sediments (e.g., sediment type 2 or 3) contain
          pesticides but the overlying sediment type 1 or 4 is barren of
          residue. In this case, pesticides may have migrated laterally from
          an adjacent subterranean contaminated zone. On the other hand, it
          could be argued that this contamination profile is the result of
          complete removal of pesticides from the overlying sediment through
          either breakdown or migration processes.

                In 13 (36%) of 36 cores, pesticides were detected in the
          premarsh sediments. In all of these cases, the overlying marsh
          sediment sequence was also contaminated. Pesticides were never
          detected in premarsh sediments if the overlying marsh sediment was
          not contaminated. Hence, although vertical migration of pesticides
          has occurred in St. Lucie County mosquito control impoundments,
          mean migration distances are difficult to quantify because the
          pesticide samples were taken over the entire length of the sediment
          type. In addition, there is no evidence of lateral migration.

                It was initially hypothesized that organic        rich sediments
          would preferentially adsorb pesticide residue and       hence a direct
          correlation between TOM and pesticide concentration was thought to
          be obtainable. However, the results of this study did not support
          this hypothesis (Figure I and 2). There were a number of instances
          in which pesticides were detected in surface sediments with low or
          no organic content. The apparent correlation between TOM and
          pq*-tic-i-des,,may.,,be coincidental since Marsh sediments are typically
          [email protected].'..' Hence most,,-.of -the, marsh surface exposed to pesticide
          w4-p:,-organic rich-,,at the -time. of, treatment. Subsequent to treatment,
          th'e--pesticide may have either remained in place, or migrated
          downward and into the premarsh, organic poor, sediments (Figure 2).
          This migration produced a pesticide concentration profile that
          decreased with depth, as did the organic content of the host
          sediment.

                This project was also designed to determine whether the water
          management by the Mosquito Control District had any effect on
          pesticide mobility. of particular concern was whether a well
          flushed marsh facilitated pesticide migration and the flux of
          pesticides into the Indian River Lagoon. It was initially
          hypothesized that a well-flushed impoundment would promote
          migration and hence pesticide levels might be lower in a well
          flushed-marsh in comparison to a poorly-flushed marsh. This














                                                                                  3

         relationship was not apparent. Impoundment 1 was selected for
         detailed study as a poorly-flushed site. Impoundment 2 was selected
         to represent a well-flushed site. Thirty three percent of the cores
         in Impoundment 1 contained pesticides. Sixty percent of the cores
         in Impoundment 2 contained pesticides. This provides supporting
         evidence that water management for mosquito control does not
         influence pesticide mobility. Water quality data, described below,
         supports this assessment.



                                          Water



         Pesticide Distribution Trends



              Water samples were taken from each of the 36 core holes (pore
         water) and in four transects proximal to Impoundment 1 and 2 paired
         bottom water release culverts (which continuously release bottom
         water throughout the closed season). A total of 51 pore water and
         170 culvert samples were collected and analyzed for TOM and
         pesticide content. None of the water samples contained detectible
         levels of pesticides.


         Controls on Pesticide Distribution



              Initially it was hypothesized that pesticides entering the
         Indian River Lagoon would be associated with impoundment water high
         in POM because of the binding capacity of the organic material.
         Water samples were collected at the end of the open and closed
         period and at mid-closure drawdown to determine (1) what effect
         water management has on POM exchanging with the estuary, (2)
         whether pesticides are associated with this water, and (3) whether
         or not water management was enhancing the flux of pest ic [email protected]'&
         the Indian River Lagoon." The results of this study-indicat6't-ha--t1
         the water management practices of St. Lucie County mosquitoi coiftf&F
         have no detectable effect on the concentration of p6stlcideliE@
         entering the Indian River Lagoon.
                                                                                  fIT














           4


                                   CONCLUDING REMARKS



           (1) Pesticides were detected within the sediments of St. Lucie
           County mosquito control impoundments.,

           (2) Pesticides have migrated from the treated sediments downward
           into sediment layers that were not contaminated during the original
           application of pesticides.

           (3) There is no obvious graphical relationship between the presence
           or absence of pesticides and sediment: TOM.

           (4) Pore waters collected from the sediment core holes did not
           contain pesticides even if the sediment yielded positive results.

           (5) Water management of the impoundments does not appear to have
           any effect of pesticide mobility through the sediments.

           (6) Estuarine water circulating through the impoundments never
           contained detectible levels of pesticide.

           (7) The significance of pesticide levels detected during this study
           is unknown and beyond this study's scope of work. Additional
           studies will be required to determine the effect of pesticide
           residue on biological systems in this area.















                               ADDITIONAL STUDIES

        (1) Examine pesticide levels in adjacent estuarine areas.

        (2) Examine biological uptake of pesticides by the organisms that
        inhabit the impoundments.
        (3) Examine the impact of increased microbial activity re@;ultin
                                                                        g:
        from management practices on pesticide degradation.

        (4) Examine the applicability and practicality of   mechanical or.,
        bio-remediation for the impoundment sediments.













           6








                            WEIGHT PERCENT TOM VS DEPTH
                                           Cores From General
                                       Impoundment Pesticide Survey


                        0                           +
                             4- . ++ +          ++ *            +
                                       +       +      ++          +
                       20 -            +                      +
                     -40  -   +        +               +
                              +        +
                 D   -60         +++
                 e
                 p   -80  -
                 t
                 h  -100   +


                    -120


                    -140


                    -160
                        0         20         40        60         80        100
                                          Weight Percent TOM


                                       Non-Pesticide   + Pesticide















           Figure- 1,[email protected],.Pestic'ide presenc6 as a function of weight. percent TOM
            and dept;h-.;,,S-amples plotted are from the 18 general siirvey cores.












                                                                              7













                                          TOM
                   Key

              Pest Surface
              Non-Pest Surface
              Pest Beneath Pest
              Non-Pest Beneath Pest 20             80
           0  Pest Beneath Non-Pest
           El Non-Pest Beneath Non-Pest





                              40                         60







                                                       G
                        60                                     40








                  80                                                 20





         CaC03                                  -  El            0 C@?Ip ca. Noncombustible
                         20          40          60         80             (CLASTIC)







           Figure 2 -7..Ternary diagram 7jillustrating relations-hIp-betweigRii
                -s@edimeht. composition" ,depth,, and pest ic..ide!.-,,ccintelft@i@) h bf',F














                                                                                                               7







                                                                                         Indian
                                                                                          River
                                                                                       Lagoon
                                                                                                           Ov
                                                                                                          C,
                                     North                                        Culverts



                                                                                       Dike




















                                               2BM50
                                   213CR                           2AM50
                                  0     0                              0
                              2B R1 00

                                                             2ACR 0


                                                                 0
                                                           2AR1 00
                                                                                            ,@ian
                                                                                           ve r

                                                                                           oon
                                                                                                           c@



                                                                                                        b


                                                                                                      A





























                  Figure 3         Location Map of Culvert Water Sampling Stations:
  4                                                  Impoundment 2











                                                                                                             NOAA COASTAL SERVICES CTR LIBRARY



                                                                                                             3 6668 14111326 8