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Heavy Metal, Polychlorinated B l*phenyl, and Pesticide Levelg in Oysters (Crassostrea virginica) 1979 Maryland Oyster Spat Survey Office of Environmental Programs TD Maryland 196 .M4 G37 Department of Health and 1981 Mental Hygiene HEAVY METAL, POLYCHLORINATED BIPHENYL, AND PESTICIDE LEVELS IN OYSTERS (Crassostrea virginica) 1979 MARYLAND OYSTER SPAT SURVEY U.S . DEPARTMENT OF COMMERCE NOAA COASTAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE CHARLESTON, SC 29405-2413 Mary Jo Garreis, Faith A. Pittman Water Management Administration Office of Environmental Programs Department of Health and Mental Hygiene August, 1981 PROPERTY of CSC Library MARYLAND DEPARTMENT OF HEALTH AND MENTAL HYGENE ACKNOWLEDGEMENT We thank Mr. William B. Van Sant of the Office of Environmental Programs, Department of Health and Mental Hygiene for the collection of samples and the staff of the Laboratories Administration, Maryland Department of Health and Mental Hygiene for shellstock tissue analyses. The preparation of this report was funded in part by the National Oceanic and Atmospheric Administration, Office of Coastal Zone Management, through the Maryland Department of Natural Resources, Tidewater Administration, Coastal Resources Division. TABLE OF CONTENTS Page Introduction ............................................... 1 Purpose of Study ....................................... 1 Study Area Description ................................. 1 Methods and Materials ..................................... 1 Sample Collection ...................................... 1 Laboratory Analyses .................................... 3 Statistical Analyses ................................... 3 Results ................................................... 3 Discussion ................................................ 16 Bibliography .............................................. 18 List of Figures Page Figure 1 Sample Locations for 1979 Survey 2 Figure 2 Chesapeake Bay 9 Figure 3 Potomac River (Sub-Basin 02-14-01) 10 Figure 4 Patuxent River (Sub-Basin 02-13-11) 11 Figure 5 Several Tributaries of the Chesapeake Bay .12 (Sub-Basin 02-13-05) Figure 6 Choptank River (Sub-Basin 02-13-04) 13 Figure 7 Little Choptank River (Sub-Basin 02-13-04). 14 Figure 8 Honga River (Sub-Basin 02-13-04) 14 Figure 9 Tangier Sound (Sub-Basin 02-13-03 and, 02-13-02) 15 List of Tables Page Table la 1979 Heavy Metal, PCB and Pesticide Levels in 4 Oysters from the Chesapeake Bay and its Tributaries Table lb 1979 Heavy Metal, PCB and Pesticide Levels in 5 Oysters - Potomac River and its Tributaries (Sub-Basin 02-14-01) Table lc 1979 Heavy Metal, PCB and Pesticide Levels in 6 Oysters from the Patuxent River and its Tributaries (Sub-Basin 02-13-11) Table id 1979 Heavy Metal, PCB and Pesticide Levels in 7 Oysters - Choptank River and its Tributaries (Sub-Basin 02-13-04) Table le 1979 Heavy Metal, PCB and Pesticide Levels in 8 Oysters - Upper Tangier Sound and its Tributaries (Sub-Basins 02-13-03 and 02-13-02) Table 2 Heavy Metal, PCB and Pesticide Means (expressed 9 in ppm) in Oysters Sampled from the Mainstem of the Chesapeake Bay in 1979 Table 3 Heavy Metal, PCB and Pesticide Means (expressed in 10 ppm) for Oysters Sampled from Different Areas of the Potomac River in 1979 Table 4 Heavy Metal, PCB and Pesticide Means (expressed in 11 ppm) for Oysters Sampled from Different Areas of the Patuxent River in 1979 Table 5 Heavy Metal, PCB and Pesticide Means (expressed in 12 ppm) for Oysters Sampled from Several Rivers in 1979 Table 6 Heavy Metal, PCB and Pesticide Means (expressed in 13 ppm) in Oysters Sampled from Different Areas of the Choptank River in 1979 Table 7 Heavy Metal, PCB and Pesticide Means (expressed in 14 ppm) in Oysters Sampled from the Little Choptank River in 1979 Table 8 Heavy Metal, PCB and Pesticide Means (expressed in 14 ppm) in Oysters Sampled from the Honga River in 1979 Table 9 Heavy Metal, PCB and Pesticide Means (expressed in 15 Oysters Sampled from the Tangier Sound Area in 1979 iii ABSTRACT Maryland's Office of Environmental Programs began participating in the annual oyster spat survey sponsored by the University of Maryland's Sea Grant Program in the fall of 1979. Oyster samples were collected from 48 sites in the Chesapeake Bay and its tributaries and analyzed for heavy metal, PCB and pesticide levels. This effort was initiated to create a continuous record of the levels of these substances in oyster tissues on a broad Bay wide scale in a small time frame. Ranges, medians, and means and standard deviations were determined for the entire Chesapeake Bay and for some major river systems. Sub-basins were further divided and heavy metal, PCB and pesticide means for different areas determined. Trends suggested by the data were discussed and as the data base is expanded each year it is expected that the significance of some of these trends may be determined. vi INTRODUCTION Purpose of Study The University of Maryland Sea Grant Program sponsors an annual oyster spat survey cruise to determine recruitment trends for Chesapeake Bay oyster populations. Participants include academic institutions, government agencies, and private citizen groups. Personnel from Maryland's Office of Environmental Programs began participating in the cruise in 1979 to collect adult oysters for heavy metal, PCB, and pesticide analysis. This effort was initiated to create a continuous record of heavy metal, PCB, and pesticide levels in oyster tissue on a broad Bay wide scale. Study Area Description The Chesapeake Bay is the largest estuary in the United States. The Bay and its tributaries cover a total area of approximately 4400 square miles of surface water of which 2475 square miles are in Maryland. Within the Maryland portion, the Bay proper covers 1310 square miles, while the remaining area (1165 square miles) consists of tidal tributaries. The Chesapeake Bay is approximately 200 miles in total length; the Maryland portion extends 125 miles southward. There are approximately 3950 square miles of tidal shoreline in the State of Maryland. The average depth of the open Bay is 28 feet and the average depth of the entire system, including tributaries, is 21 feet. The deepest area of the Bay lies in the Maryland portion off Bloody Point at the south end of Kent Island. That portion of the Chesapeake Bay belonging to Maryland includes the Bay and its tributaries which lie north of Smith.Point at the entrance to the Potomac River. All of the Potomac River, except for its southern tributaries and the area within the District of Columbia, is owned by the State of Maryland. The Maryland - Virginia line extends from the mouth of the Potomac River through the middle of Pocomoke Sound on the Eastern Shore. METHODS AND MATERIALS Sample Collection Crassostrea virginica were collected using harvesting gear aboard the University of Maryland's R/V Aquarius from September 24 thru October 5, 1979. Oysters taken from 48 sites were analyzed for heavy metal, PCB and pesticide contamination (Figure 1). All oysters were adult animals of commercial size. Commercial size for oysters in the State of Maryland is 2@ 3 inches. 979 33 7 17 V 01. 0 5 10 miles FIGUIM I SAMPLE LOCATIONS MR 1979 SURVEY -3- Laboratory Analyses The shellfish were scrubbed clean, shucked and drained and the shells discarded. Each sample was a composite of oyster meats collected from a single location. The number of animals used in each sample was determined by the grams of tissue necessary for the analyses. For pesticide and PCB analyses, approximately 200 grams of shellfish meat were homogenized and a 100 gram portion was analyzed. All PCB and pesticide analyses were in accordance with the Food and Drug Administration's Pesticide Analytical Manual (1977). For heavy metal analyses, approximately 200 grams of shellfish meat was homogenized. Twenty to thirty grams of the homogenate were used for all heavy metal analyses except mercury and arsenic. Analysis for mercury required 5 - 10 grams of homogenate while arsenic analysis required 30 - 50 grams of homogenate. The shellfish were analyzed for copper, zinc, cadmium, chromium and lead in accordance with Chemical Procedures: NSSP - Collection,_Preparation and Analysis of Trace Metals in Shellfish (1975). Arsenic was analyzed in accordance with Official Methods of Analysis of the Association of Official Agricultural Chemists (1975) and mercury was analyzed in accordance with methods presented by Munns and Holland (1977). Laboratory results for heavy metals, PCB9j and pesticides were recorded in parts per million (ppm) wet weight. Results of lead, chromium and arsenic analyses were sometimes recorded as less than ( < ) detectable limits Non-detectable levels of PCBs and pesticides were recorded as zero. Statistical Analyses Heavy metal, PCB and pesticide ranges, medians, means and standard deviations were determined for the entire Bay and for some major river systems. Sub-basins were further divided and heavy metal, PCB and pesticide means for different areas determined. Heavy metal, PCB and pesticide levels recorded as less than detectable limits, trace or as non-detectable were considered zero when calculating statistical parameters. Means and standard deviations less than detectable limits were recorded as zero. RESULTS Tables la thru le present statistical parameters evaluated for the entire Bay and for some major river systems. Figures 2 thru 9 show sub-basins of the Bay and Tables 2 thru 9 present the heavy metal, PCB and pesticide means in the.sub-basins. TABLE la 1979 HEAVY METAL, PCB AND PESTICIDE LEVELS IN OYSTERS FROM THE CHESAPEAKE BAY AND ITS TRIBUTARIES Heavy Metals Range Mean- Standard Deviation median (n = 4S)* (pr-M) (ppm) (Ppm) (ppm) CU, 6.39 - 43.9 24.2 9.7 23.0 Zn 248 - 719 486 107 490 pb all samples <0.5 0 0 <0.5 Hg 0.002 - 0.015 0.008 0.003 0.008 Cd 0.23 - 1.66 0.73 0.35 0.64 Cr <0.1 - 0.23 0 0 <0.1 As <0.05 - 1.27 0.24 0.34 0.06 ----------------------------------------------------------------------------- rinated ny s OlYtpc) '1Z Range Mean Standard Deviation Median (n=48) (ppm) (ppm) (Ppm) (ppm) PCB 1260 ND t - 0.020 0.002 0.005 ND t PCB 1254 ND t - 0.050 0.010 0.010 0.009 -------------------------------------------------------------------------------- Pesticides Range Mean Standard Deviation Median (n - 48)* (ppm) (ppm) (ppm) (ppm) Hexachlorobenze ne - all samples ND t 0 0 ND t ME ND t - 0.004 0.002 0.001 0.002 aBHC ND t t - trace 0 0 ND Lindane all samples ND t 0 0 ND t Chlordane 0.002 - 6.020 0.008 0.003 0.008 Heptachlor Epoxide all samples ND t 0 ND t MD ND' - 0.010 0.001 0.002 0.001 DDT all samples ND t 0 0 ND t Dacthal all samples ND t 0 0 ND t Dieldrin ND t - 0.007 0.002 0.001 0.002 Endrin all sanples ND t 0 0 ND Toxaphene all samples ND t 0 0 ND t sample size t ND - Not Detectable NOTE: Heavy metal, PCB and pesticide samples recorded as less than detectable limits, trace or not detectable were considered zero when calculating means and standard deviations. -5- TABLE 1b 1979 HEAVY METAL, PCB AND PESTICIDE LEVELS IN OYSTERS POTOMAC RIVER AND ITS TRIBUTARIES (Sub-Basin 02-14-01) Heavy Metals Range Mean Standard Deviation median (n 8)* (Ppm) (Ppm) (ppm) (Ppm) Cu 6.39 - 31.2 14.3 8.2 13.0 Zn 248 - 453 337 68 357 Pb all samples <0.5 0 0 <0.5 Hg 0.006 - 0.013 0.010 0.002 0.010 Cd 0.23 - 0.55 0.38 0.11 0.37 Cr <0.1 - 0.14 0 0 <0.1 As <0.05 - 0.80 0.31 0.34 0.24 ------------------------------------------------------------------------------------ Polychlorinated Range Mean Standard Deviation Median Biphenyls (n = 8)* (ppm) (Ppm) (Ppm) (Ppm) PCB 1260 all samples NDI 0 0 NDt PCB 1254 0.009 - 0.050 0.024 0.015 0.020 -------------------------------------------------------------------------------- Pesticides Range Mean Standard Deviation Median (n = 8)* (ppm) (Ppm) (Ppm) (ppm) Hexachlorobenzene all samples NDt 0 0 ND, ME trace- 0.004 0.002 0.001 0.002 t aBHC ND - trace 0 0 Nr@ Lindane all samples NDt 0 0 NDt Chlordane 0.005 - 0.020 0.011 0.006 0.010 Heptachlor Epoxide all samples NDt . 0 0 NDt DDD trace- 0.010 0.003 0.003 0.002 MT all samples NDt 0 0 Nr@ Dacthal all samples ND 0 0 WDt Dieldrin NDt - 0.002 0 0.001 trace Endrin all samples NDt 0 0 N Dt Toxaphene all samples Nr@ 0 0 NDt sample size t ND = Not Detectable NOTE: Heavy metal, PCB and pesticide samples recorded as less than detectable limits, trace or not detectable were considered zero when calculating means and standard deviations. .TABLE ic - 1979 HEAVY METAL, PCB AND PESTICIDE LEVELS 114 OYSTERS FROM THE PATUXENT RIVER AND ITS TRIBUTARIES (sub-Basin 02-13-11) Heavy Metals Range Mean Standard Deviation Median (n = 3)* (Ppm) (Ppm) (Ppm) (ppm) Cu 20.9 - 30.7 24.7 5.2 22.5 Zn 402 - 594 469 109 410 Pb all samples <0.5 0 0 <0.5 Hg 0.005 - 0.010 0.007 0.003 0.006 Cd 1.09 - 1.26 1.18 0.08 1.19 Cr <0.1 - 0.1 0 0 <0@1' AS 0.68 - 1.27 1.03 0.31 1.14 ------------------------------------------------------------------------------- Polychlorinated Biphenyls Range Mean Standard Deviation Median (n - 3)* (ppm) (ppm) (ppm) (ppm) PCB 1260 0.009 - 0.010 0.010 0 0.010 t Pcb 1254 all samples NDt 0 0 ND ---------------------------------------------------------------------------- Pesticides Range Mean Standard Deviation Median (n = 3)* (ppm) (ppm) (ppm) (ppm) t Hexachlorobenzene -all samples NDt 0 0 ND ,DDE 0.002 - 0.004 0.003 0.001 0.003 t (XBHC NDt- trace 0 0 ND Undane all samples NDt 0 0 ND t Chlordane all samples 0.005 0.005 0 0.005 jHeptachlor Epoxide all samples NDt 0 0 ND t DDD trace - 0.002 0.001 0.001. 0.001 DDT all samples ND t 0 0 ND t Dacthal all samples ND t 0 0 ND t Dieldrin 0.001 - 0.002 0.001 0.001 0.001 Endrin all samples ND t 0 0 ND t Toxaphene all samples NDt 0 0 NDt * sample size t ND = Not Detectable NOTE: Heavy metal, PCB and pesticide samples recorded as less than detectable limits, trace or not detectable were considered zero when calculating means and standard deviations. -7- TABLE id - 1979 HEAVY METAL, PCB AND PESTICIDE LEVELS IN OYSTERS - CHOPTANK RIVER AND ITS TRIBUTARIES (Sub Basin 02-13-04) Heavy Metals Range Mean Standard Deviation Median (n . 9)* (Ppm) (Ppm) (ppm) (ppm) Cu 23.9 - 43.9 35.2 6.3 33.9 Zn 497 - 639 562 45 557 Pb all samples <0.5 0 0 <0.5 Hg 0.007 - 0.015 0.011 0.003 0.011 Cd 0.76 - 1.34 1.01 0.18 1.00 Cr <0.1 - 0.23 0.13 0.10 0.16 As <0.05 - 1.04 0.22 0.33 0.10 --------------------------------------------------------------------------- Po yc rinated Biphenyls Range Mean standard Deviation Median (n = 9)* (ppm) (ppm) (ppm) (ppm) PCB 1260 NDt - 0.020 0.002 0.007 NDt PCB 1254 NDt - 0.020 0.009 0.005 0.008 ----------------------------------------------------------------------------------- Pesticides Range Mean Standard Deviation Median (n = 9)* (ppm) (ppm) (ppm) (ppm) Hexachlorobenzene all samples Wnt 0 0 NDt DDE 0.001 - 0,003 0.002 0.001 0.002 t aBHC all sample. NDt 0 0 ND Lindane all samples NDt 0 0 NDt Chlordand 0.007 - 0.010 0.009 0.001 0.010 Heptachlor Epoxide all samples NDt 0. 0 ND t DDD trace 0.002 0.001 0.001 0.001 DDT all samples NDt 0 0 ND t Dacthal all samples NDt 0 0 ND t Dieldrin 0.002 - 0.003 0.003 0 0.003 Endrin all samples ND t 0 0 NDt Toxaphene all samples ND t 0 0 ND t sample size t ND Not Deter-table NOTE: Heavy metal, PCB and pesticide samples recorded as less than detectable limits, trace or not detectable were considered zero when calculating means and standard deviations. TABLE le - 1979 HEAVY METAL, PCB AND PESTICIDE LEVELS IN OYSTERS - UPPER TANGIER SOUND AND ITS TRIBUTARIES (Sub Basins 02-13-03 and 02-13-02) Heavy Metals Range Mean Standard Deviation Median (n (ppm) (Ppm) (Ppm) (ppm) Cu 12.5 - 32.6 26.0 6.7 27.4 Zn 347 - 715 541 107 548 Pb all samples <0.5 0 0 - <0.5 Hg 0.002 - 0.014 0.007 0.003 0.007 Cd 0.30 - 0.65 0.48 0.11 0.46 Cr <0.1 - 0.17 0 0 <0.1 As <0.05 - 0.14 0 0.05 <0.05 ----------------------------- - -- - - -- - ---- - ---- - ------------------ Biphenyls Range Mean Standard Deviation Median (n 8)* (Ppm) (ppm) (ppm) (Ppm) PCB 1260 ND.- 0.010 0.006 0.004 0.006 PCB 1254 NDt@- 0.004 0.001 0.002 ND t --------------------------------------------------------------------------------- Pesticides Range Mean Standard Deviation Median (n = 8)* (ppm) (Ppm) (ppm) (Ppm) Hexachlorobenzene all samples NO t 0 0 ND DDE NDt- 0.001" 0.001 0 0.001 OtBHC NDt- trace 0 0 ND t Lindane all samples NDt 0 0 ND t Chlordane 0.002 - 0.005 0.004 0.001 0.004 Heptachlor Epoxide all samples ND t 0 0 ND t DDD NDt- 0.001 0 0 trace DDT all samples ND t 0 0 ND t Dacthal all samples ND t 0 0 ND t Dieldrin ND t- 0.001 0 0 mt/trac- t Endrin all samples ND' 0 0 ND Toxaphene all samples ND t 0 0 ND t sample size t ND = Not Detectable NOTE: Heavy metal, PCB and pesticide samples recorded as less than detectable limits, trace or not detectable were considered zero when calculating means and standard deviations. -9- ONNIONER assesses INERNMEN 19 0 10 Miles LU It cc w 5 4 3 2 nGUFT 2 - CRESAPEAYE BAY TABLE 2 HEAVY METAL, PCE AND PFSTXCMZ LXVCJ (*37rassod in ppm) 32; OYSTERS SAMPLED FROM THE MkINSTEM OF THE OCESAPEAKE BAY rN 1979 'Location CU Zn 59 Cd Cr AS 1 (1) 10.9 398 0.006 0.28 0 0.80 2 (1) 25.5 616 0.006 0.97 0 0.08 3 (1) 14.8 536 0.006 0.57 0 0.58 4 (1) 16.9 508 0.008 0.84 0 0.42 5 (1) 24.1 S27 0.007 0.88 0.12 0 6 (1) 13.6 416 0.006 0.43 0.15 0 7 (1) 29.2 541 0.006 0.82 0 0.47 a (1) 41.1 719 0.007 1.49 0.13 0 9 (1) 42.9 611 0.006 1.66 0.12 0.56 Location DDE PO 1260 PCB 1254 Chlordane DDD Dieldrin i (1) 0.001 0 0.010 0.007 trace 0.001 2 (1) 0.001 0 0.010 0.010 0.001 0.002 3 (1) 0.001 0 0.008 0.006 trace 0.001 .4 (1) 0.002 0 0.010 0.008 0.001 0.001 5 (1) 0.001 0.010 0 0.009 0.002 0.002 6 (1) 0.002 0 0.020 01009 0.002 0.007 7 (1) 0.001 0 0.010 0.008 0 0 (1)) O.DO2 0 0.020 0.008 0.003 0.001 1 0.002 0 0.020 0.010 0.003 0.002 S-Ple size in Parentheses NOTE: Heavy metal, PCB and pesticide samples recorded as less than detectable limits, trace or not detectable are considered zero when calculating means. 0 5 K@. Nautical I miles GUM 3 POTOMAC RXVER (Sub-Basin 02-14-01) MONSOON 001001010 TABLE 3 - HEAVY METAL, PCs AND PZSTXCXM MEANS taxpreissed in Pro) FOR . OrSTEN SAMPLED FROM M77MENT AREAS OF THE POTOMAC I=R XN 1979 Location - cu Zn R9 Cd Cr AS A - riddle Potomac River (6) 15.7 347 0.010 0.37 0 0.41 B - Breton say (1) 6.96 248 0.009 0.27 0 0 C - Wiccmicc River (1) 13.3 363 0.610 0.52 0 0 Location DM P(21260 PM1254 Chlordane DOD Dieldrin A (6) 0.002 0 0.022 0.013 0.004 0 B (1) 0 0 0.050 0.005 0 0 C (1) 0.002 0 0.010 0.010 0.002 0.001 Sample size in parentheses NOTE: Heavy metal, PCB And pesticide samples recorded as less than dotec-table limits, tram or not detectable were considered zero when calculating we no. FIGURE 4 PATUMT Rl%7ER (Sub-Basin 02-13-11) N Nautical Miles Nemeses, "Useeme amemess' a- TAHIZ 4 - HEAVY ICTAL, PCB AND PZS=CXW MEANS (expressed in RXI) FOR OYS7CRS SAWLED FROK MrrERENT AREAS OF THE PATUXENT RMR 33 1979 Location - Q2 Zn H9 Cd ar as D - lower Patuxent River (2) 25.8 496 0.006 1.14 0 1.20 E - Upper Patuxent River (1) 22.3 410 0.006 1.26 0 .68 location - DOE PCB1260 PCB12S4 Chlordane DDD DJ,IAU D (2) 0.004 0.010 0 0.005 0.001 0.002 E (1) 0.002 0.010 0 0.005 0.002 0.001 - Sunple size in parentheses RM : Heavy metal, PCB and pesticide samples recorded as less than detectable limits, trace or. not detectable @sr* comidered zero whan calcuIatinq =one. C) 5 t-. U-tx C a Miles. IV LV FIGURE 5 SEVERAL TRIBUTARIES OF I M BAY (Sub-Basin 02-13-0 TABLE 5 HEAVY METAL, PCB AND PESTICIDE MEANS (espressed in ppm) FOR OYSTERS SAMPLE:D FROM SEVERAL RIVERS EN 1979 Location Cu zn Bg Cd Cr A. F Chester River (2) 24.7 467 0.006 1.04 0.18 0.08 G North Eastern Bay (1) 26.4 455 0.007 0.44 0 0 H South Eastern Day (1) 16.6 421 0.008 0.58 0 0.59 1 miles River (2) 23.4 464 0.010 0.65 0.14 0 J Wye River (2) 22.1 440 0.010 0.82 0.16 0.06 Location DDE PCB1260 P01254 Chlordane DM Dialdrin F (2) 0.002 0 0.009 0.008 0.002 0.002 G (1) 0.001 0 0.009 0.005 0 0 H (1) 0.002 0 0.010 0.009 0.009 0.002 1 (2) 0.001 0 0.008 0.006 0 0.002 1 (2) C.002 0 0.010 0.006 0 0.003 -Sample size in parentheses Notet Heavy metal, PcB and pesticide samples recorded as less than detectable limits, trace or not detectable were considered zero when calculating mearm. Nautical Miles AL. FIGURE 6 - CROPTANY RIVER (Sub-Basin 02-13-04) 00100111010 NOMENNOM MENOMONIE TABLE 6 HEAVY METAL, PCB AND PESTICIDE MEANS (expressed in ppm) IN OYSTERS SAMPLED FROM DIFFERENT AREAS OF THE CHOPTANK RIVER IN 1979 Location Cu zft H9 Cd Cr As X - Lower Choptank River (1) 23.9 497 0.007 0.76 0.13 0.13 L - Middle Choptank River (3) 34.2 558 0.010 0.97 0.12 0.42 M - Trod Avon River (2) 33.8 611 0.012 0.96 0.16 0.05 N - Broad Crook (1) 43.9 SS7 0.015 1.16 0 0 0 - Harris Crook (2) 39.3 555 0.011 1.17 0.20 0.24 Location DM PCB12&0 PCB1254 Chlordane DDD Dieldrin * (1) 0.002 0 0.010 0.008 C.001 0.002 * (3) 0.002 0.007 0.007 0.010 0.001 0.003 * (2) 0.002 0 0.014 0.008 0.001 O.DO2 N (1) 0.001 0 0.008 0.010 0 0.003 0 (2) 0.002 0 0.008 0.009 0.001 O.DO2 Semple size in parentheses Note: H"vY metal, PCs and pesticide samples recorded as less than detectable limits, trace or not detectable were considered zero when calculating means. Nautica Miles FIGURE 7 -LITTLE CHOPTAW RIVER (Sub-Basin 02-13-04) TABU 7 HEAVY METAL PCB AND PESTICIDE MEANS (expressed in pps) IN OYSTERS SAMPLED FROM THE LITTLE CHOPTANX RIVER IN 1979 Location . Cu U Rg Cd Cr As P . (1) 17.9 447 0.006 0.46 0 0.@s DDE PC81260 PCB12S4 ChlordA a DDD Dieldrin P (1) 0.002 0 0.009 0.007 0.001 0.003 - Sample size in parentheses Note: Heavy metal, PCs and pesticide samples recorded as loss than detects le limits, trace or not detectable ware considered zero when calculating means. 0 i Nautical .4 @ miles- Q9 FIGURE 8 HONGA RIVER (Sub-Basin 02-13-04) TABLE 8 HEAVY ME"rAL, PC9 AND PESTICIDE MEANS (expressed in Rea) IN OYSTERS SAMPLED FROM THE BONGA RIVER IN 1979 Location Cu Zn Hq Cd Cr As 9 (2) 13.7 462 0.008 0.54 D 0 DDE PCB1260 PC!31254 Chlordano DDD Dieldrin (2) 0.002 0.010 C 0.006 0.002 0.001 - Sample size in parentheses Note: Hoary Metal, PCB and pesticide samples recorded as less than detectable limits, tract or not detectable wero@considered zero when calculating means. nL 14) ies, Q, .0 H.. RIVER Nautical' miles S ST -601 FIGURE 9 TANGIER SOUND (S@Basins 02-13-03 and 02-13-02) TABLE 9 WAVY NETAL, PCB AND PESTICIDE MEANS (expressed in ppm) Lq OYSTERS SAMPLED FROM THE TANGIER SOUND AREA IN 1979 location - Cu zn qq Cd Cr As R - Upper Tangier Somd (4) 23.9 532 0.009 O.SO 0 0 S - ?ishinq Say (1) 32.6 619 0.007 0.54 0 0 T - Nanticoke River (1) 30.6 538 0.008 0.40 0 0 U - Wicomico River (2) 24.6 522 0.004 0.46 0 0 zacation - DOE PC31260 PCB1254 Chlordane ODD Deildrin R (4) 0 0.006 0 0.004 0 0 S (1) 0.001 0.010 0 0.00S 0.001 0 T (1) 0.001 0.008 0 0.004 0 0 a (2) 0.001 0 0.004 0.004 0 0 *SAWle size in parentheses 4M: 9*avy matal, PCB And pesticide samples recorded as less than detectable limits, trace Or not detectable were considered zaro whan calculatinq means. -16- DISCUSSION Several trends were suggested by the 1979 data when evaluated by major river systems. Mean levels of both copper and zinc in oyster tissues exhibited the following trend: Choptank River > Upper Tangier Sound > Patuxent River > Potomac River. Mercury means were approxi- mately equal in all four areas. Mean levels of cadmium in oyster tissues exhibited the following trend: Patuxent River > Choptank River > Upper Tangier Sound > Potomac River. Chromium was more prevalent in oyster tissues from the Choptank River (5E = 0.13 ppm) than in oysters from the Patuxent River, Potomac River and Upper Tangier Sound (R = 0 ppm). Mean levels of arsenic exhibited the following trend: Patuxent River > Potomac River > Choptank River > Upper Tangier Sound. It is difficult to determine what may contribute to the heavy metal differences between river systems and the significance of these levels. The trends may indicate natural differences between areas or possible sources associated with human habitation. Analyses of the 1979 data by station location within.the river systems indicated a definite trend. Mean levels of copper, zinc and cadmium in oyster tissues were greater upstream than downstream in the Chesapeake Bay mainstem, Choptank River and Upper Tangier Sound. Some of these areas are not located near point source discharges suggesting that other factors affect the system. Huggett et al. (1975), investigating salinity effects on the up- take of copper and zinc by oysters in rivers in North Carolina and Virginia noted a concentration gradient. Oysters living in fresher waters had higher concentrations of metals than those in more saline waters. Theories involving concentration gradients of copper and zinc dissolved in water or as particulates in sediment were not supported by the data. Huggett et al. (1975) suggested the following possible alternate explanations. 1. oysters may take up metals from the environment with cal- cium by a nonspecific ion-transport mechanism in order to satisfy the high calcium requirements for shell deposition. in low salinity waters, where calcium levels would be lower, the animals may have to extract calcium more efficiently and greater quantities of other cations may be taken up as a result. 2. In high salinity waters, cations that are at higher concen- trations than copper and zincmay take away binding sites. 3. Chelation of metals in solution by natural organics like fulvic acids would make elements more available to the oyster. Assuming that humic substances are from decaying plant mater- ials, the concentrations of fulvic acids would decrease with increasing salinity because of dilution. Mercury means from different areas within rivers in 1979 were similar. Chromium and arsenic means on the other hand, exhibited greater differences between areas but no consistent trend were evident. In the Chesapeake Bay mainstem data analyses, location 2 had higher levels of copper, zinc, and cadmium than might have been ex- pected when compared to other mainstem samples. The Calvert Cliffs Nuclear Power Plant, located nearby, may have had some influence. Mercury, chromium and arsenic levels in oyster tissues did not appear to be affected. Evaluation of the 1979 data according to major river systems indicated that DDE, PCB 1260, PCB 1254, chlordane, DDD and dieldrin were the only pesticides recurring regularly in oyster tissues. DDE, DDD, and dieldrin means did not exhibit much variation between rivers while PCB 1260, PCB 1254 and chlordane did. PCB 1254 levels in Chesapeake Bay shellfish reported by Eisenberg et at. (1980) were in general agreement with levels found during the 1979 Oyster Spat Survey. Since PCBs and pesticides are synthetic substances their presence indicates man's impact on the environment. In the case of pesticides, the most likely source in the environment results from agricultural useage. Pesticide differences between rivers may be.indicative of land use patterns. Copper, cadmium, PCB 1254, dieldrin and DDE levels in oysters reported by Garreis and Pittman (1981) in a study of heavy metal, PCB and pesticide levels in Choptank River oysters and soft shell clams were consistent with Choptank River levels reported here. Levels of zinc, mercury, PCB 1260, chlordane and DDD in oysters were greater in the Choptank River report. The Choptank River report did not incorpo- rate samples taken from tributaries whereas the spat survey evaluation' included samples from the Tred Avon, Harris and Broad Creeks in de- termining overall means. Since the Office of Environmental Programs has only recently initiated this survey of heavy metal and pesticide levels in conjunc- tion with the Oyster Spat Survey there is inconclusive evidence at present to determine whether any of the apparent differences between rivers are significant. As this program continues and -*the data base expanded it is expected that the significance of some of these trends may be determined. -18- BIBLIOGRAPHY Eisenberg, M., R. Mallman and H.S. Tubiash. 1980 Polychlorinated Biphenyls in Fish and Shellfish of the Chesapeake Bay. Department of Commerce, Marine Fisheries Review 42(2). Garreis, M. J. and F.A. Pittman. 1981 Heavy Metal, Polychlorinated Biphenyl, and Pesticide levels in Oysters (Crassostrea.virginica) and Soft Shell Clams (Ahja arenaria) from the Choptank River, Maryland. -Office of Environmental Programs Report, Maryland .Department of Health and Mental Hygiene. Huggett, R.J., F. A. Cross, and M. E. Bender. 1975. Distribution of copper and zinc in oysters and sediments from three cQastal-plain estuaries. Proceedings of a Symposium on Mineral Cycting on Southeastern Ecosystems, ERDA Symposium Series, CONF-740513, 224-238. i 3 6668-00002-1-032