Volume 15/Number 4/April 1984

Marine Pollution Bulletin. Vol. 15, No. 4, pp. 159~161, 1984. Printed in Great Britain.

Metals in Crab, Oyster and Sediment in Two South Carolina Estuaries The blue crab Callinectes sapidus and the eastern oyster Crassostrea virginica have the ability to concentrate metals from the marine environment (Frazier, 1975; Hutcheson, 1974; Moore, 1971). Numerous domestic and industrial effluents leads to estuarine pollution along the South Carolina coast. So, from August 1979 to May 1981, cadmium, copper, lead and zinc concentrations were deter- mined quarterly for crab, oyster and bottom sediment from two estuarine areas in the vicinity of Charleston, South Carolina (Lat. 32 ° 50', Long. 80 ° 00').

Four paired sampling stations were selected according to their salinity and proximity to urban and industrial activities. Foster Creek, salinity 10%oo, a tributary of the Wando River, and Shute's Folly Island, salinity 25%0, located near the centre of Charleston harbour, receive heavy commercial and military ship traffic, industrial and muni- cipal waste. The Ashepoo River at Mosquito Creek, salinity 10%o, and St Helena Sound at the mouth of Rock Creek, salinity 25°0 , are located approximately 35 miles south- west of Charleston, and receive little industrial and urban discharges and little ship traffic.

Crabs were caught in commercial crab pots baited with dead fish. The animals were taken to the laboratory in plastic insulated boxes and kept refrigerated (alive) until tissue sections were removed. The claw muscles and the large

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TABLE 1

Analysis of NBS standard reference materials (/ag g - I)

SRM 1566 (oyster tissue) SRM 1577 (bovine liver) Metal n* Certified Found n* Certified Found

Cadmium 37 3.5 +_0.4 3.5 +0,6 Copper 15 63.0+3.5 66 +7 11 193+10 185+17 Lead 37 0.48+0.04 0.51+0.16 Zinc 14 852 +14 854 +_50 11 130+10 128+3

*n is the number of samples analysed.

muscles that operate the fifth pereiopod (back-fin or paddle), and are the major edible tissue, were dissected (raw) immediately after crabs were killed. Tissue samples were placed into linear polyethylene bottles, homogenized with a Polytron unit, and kept frozen at - 30 ° until analysis.

Oysters were collected from three intertidal beds. The Ashepoo River sampling site did not have an oyster bed. The animals were collected by hand at low tide when the beds were exposed, placed in plastic bags, and brought to the laboratory where they were kept refrigerated (alive) until the tissues were removed. The oysters were thoroughly washed with tap water to remove surface mud, then shucked with stainless steel knives. The tap water contained 0.002, 0.217, 0.005 and 0.03 tag ml- ' of Cd, Cu, Pb and Zn, respectively. Three composite samples of 250 g of oyster meat and shell liquid were obtained from each bed. Any shell fragments found in the sample were removed with stainless steel tweezers. Approximately 20 shucked oysters were thoroughly homogenized to make each 250 g composite sample, which had moisture contents of 90-t-3°70. The composite samples were stored in clean plastic containers at

- 30°C until analysed. Sediment samples were collected at the intertidal oyster

beds. Subtidal sediment samples were collected from the Ashepoo River. The top 3 cm of the sediment surface was

TABLE 2

Mean concentrations of metals 0ag/g wet wt) in blue crab muscle from stations in South Carolina estuaries

Location Aug. 79 Nov. 79 Feb. 80 May 80 Aug. 80 Nov. 80 May81 Mean* t S .D. t Range~ n~-

Cadmium Charleston harbour 0.019 0.252 n.r. n,c. 0.022 0.016 0.013 0.051 a 0,139 0.002-1.00 86 Foster Creek 0.024 0.078 0.020 0.034 0.038 0.017 0.032 0.034 a 0.079 0.002-0.74 I l 1 St Helena Sound 0.020 0.015 n.c. 0.013 0.018 0.011 0.007 0.015 a 0.015 0.002-0.098 78 Ashepoo River 0.035 0.019 0,012 0.023 0.015 0.013 0,016 0.023 a 0 . 0 2 1 0.002-0.111 11 l

Copper Charleston habour 13.2 6.2 12.1 n.c. 9.7 8.2 4.2 9.8 b 5.0 1.2-30.0 1 l0 Foster Creek 12.6 4.9 6.6 8,8 9.2 7.7 5.8 7.5 a 3.7 1.2-23.7 149 St Helena Sound 13.5 4.6 n.c. 6,2 5.8 5.7 4.1 7.6 a 5.3 1.2-34.0 113 Ashepoo River 16.3 5.0 4.5 6.7 7.3 3.2 5.2 8.0 a'b 6.8 1.3-53.9 140

Lead Charleston harbour 0.070 0.106 n.r. n,c. 0.034 0.036 0.027 0.060 b 0.074 0.010-0.47 96 Foster Creek 0.045 0.057 0.034 0,036 0.023 0.028 0.054 0.044 a'b 0 . I l l 0.010-1.20 120 St Helena Sound 0.073 0.050 n.c. 0,063 0.013 0,028 0.017 0.048 a'b 0.049 0.010-0.31 106 Ashepoo River 0.042 0.057 0.038 0,030 0.025 0,029 0.030 0.037 a 0.026 0.010-0.12 128

Zinc Charleston harbour 33.7 35.2 26.9 n.c. 39.8 37,1 18.1 34.3 c 9.8 6.9-57.6 106 Foster Creek 34.9 28.6 30.8 28.7 41.0 35,4 31.7 31.9 c'a 9.5 10.3-84.4 146 St Helena Sound 30.3 24.0 n.c. 26.3 29.9 36,0 26.2 28.5 b 8.2 14.8-54.0 113 Ashepoo River 33.9 28.6 25.9 28.0 33.8 25,5 29.0 29.8 a'b 9.3 3.9-69.0 140

* Mean values for each metal with the same letter were accepted to be equal 6o > 0.05). ~Mean, standard deviation and range of all samples analysed for each station. n.r., values not reported due to contamination of samples during analysis. n.c., indicates that no samples were collected.

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TABLE 3

Mean concentrations of metals (/~g/g wet wt) in eastern oysters from stations in

Marine Pollution Bulletin

South Carolina estuaries

Location Aug. 79 Nov. 79 Feb. 80 May80 Aug. 80 Nov. 80 May81 Mean*1- S.D.1- Range1- n l

Cadmium

Charleston harbour 0.37 0.31 0.48 0.34 0.24 0.18 0.26 0.31 a 0.11 0.01-0.48 17 Foster Creek 0.46 0.27 0.49 0.60 0.40 0.14 0.50 0.42 a 0.17 0.05-0.6 18 St Helena Sound 0.40 0.26 0.72 0.33 0.10 n.c. 0.52 0.36 a 0.20 0.03-0.72 16

Copper

Charleston harbour 37.9 10.8 24.8 11.5 31.5 21.9 4.98 20.9 a 13.2 4.0-47.9 18 Foster Creek 60.9 20.1 37.7 23.7 29.6 19.5 4.31 29.8 a 18.8 2.6-72.5 20 St. Helena Sound 17.7 7.2 10,0 6.8 10.3 n.c. 7.7 10.2 b 4.2 5.2-19.8 16

Lead Charleston harbour n.r. 0.07 0.14 0,08 0.25 0.33 1.13 0.27 a 0.42 0.02-1.64 14 Foster Creek n.r. 0.06 0.15 0.12 0.26 0.29 0.07 0.16 a 0.11 0.02-0.35 14 St. Helena Sound n.r. 0.07 0.43 0.10 0.47 n.c. 0.09 0.25 a 0.27 0.02-0.84 13

Zinc Charleston harbour 613 205 604 287 604 401 507 426 a 250 56-1145 17 Foster Creek 1031 595 936 539 640 439 886 762 b 312 315-1261 21 St Helena Sound 264 226 281 269 246 n.c. 316 260 c 54 162-343 16

*Mean values for each metal with the same letter were accepted to be equal (p > 0.05). 1-Mean, standard deviation and range of all samples analysed for each station. n.r., values not reported due to contamination of samples during analysis. n.c., indicates that no samples were collected.

sampled. The samples were placed in plastic containers and brought into the laboratory where they were kept frozen at -30°C until analysis.

A dry ashing procedure adapted from that of Gajan et al. (1982) was used for crab and oyster samples and a HNO3 extraction procedure adapted from that of Simpson (1979) was used for sediment samples. The mineralized sample was dissolved in 0.3 M HNO3 solution.

The resultant acid solutions of crab, oyster and sediment extracts were analysed for Pb and Cd by anodic stripping voltammetry (ASV) according to the method of Gajan et al. (1982). Zn and Cu were analysed by flame atomic absorption spectrophotometry (FAAS) using the method of Emmel et al. (1977). Calibration curves were constructed daily for ASV and FAAS analyses from standards prepared from Spec Pure ® (Johnson Mattney) metal compounds.

National Bureau of Standards SMR-1566 (oyster tissue) and 1577 (bovine liver) were included with each set of

analyses to ensure the integrity of the analytical method (Table 1). The detection limits for Cd, Cu, Pb and Zn were 0.002, 0.01, 0.005 and 0.01 ~g g-~, respectively. Metal concentrations were based on wet weight of sample, unless otherwise stated.

Generally, temporal variations exist in the concentra- tions of the four metals (Cd, Cu, Pb and Zn) in crab muscle, oyster and sediment in each station from one sampling period to another (Table 2--4). However, comparison of mean metal concentrations among the stations indicates significant differences (p ~<0.05). For the crab, those from Charleston harbour had more Cu than those from Foster Creek and the St Helena Sound, and those in the harbour had more Zn than crab from the St Helena Sound and the Ashepoo River. The harbour crab had more Pb than those from the Ashepoo River. Foster Creek crab had more Zn than those from the St Helena Sound. For the oyster, those from Foster Creek

TABLE 4

Mean concentrations of metals (/ag/g dry wt) in sediment from stations in South Carolina estuaries

Location Aug. 79 Nov. 79 Feb. 80 May80 Aug. 80 Nov. 80 May81 Mean*-t S.D. 1- Range + n1-

Cadmium Charleston harbour 0.10 0.05 0.22 0.14 - 0.03 0.01 0.11 a'b 0.80 0.01-0.27 13 Foster Creek 0.29 0.22 0.26 0.26 0.08 0.26 0.08 0.21 a 0.12 0.05-0.46 18 St Helena Sound 0.15 0.08 0.14 0.22 0.06 0.09 - 0.13 a'b 0.09 0.01-0.25 15 Ashepoo River 0.11 0.11 0.16 0.12 0.08 - 0.04 0.10 b 0.05 0.02-0.15 9

Copper Charleston harbour 2.0 1.5 5.8 3.1 2.3 2.4 2.5 2.8 b 1.5 0.4-6.6 21 Foster Creek 15.2 16.0 16.0 15.5 12.1 12.6 16.8 15.0 c 3.4 8.8-24.5 20 St Helena Sound 2.1 2.4 3.7 5.2 0.6 2.1 3.1 2.6 a'b 1.8 0.3-5.5 20 Ashepoo River 0.6 1.5 2.0 1.7 1.0 2.2 1.5 1.4 a 1.1 1.1-4.4 13

Lead Charleston harbour 6.1 1.2 8.2 1.9 5.8 5.8 2.9 5.0 a 3.4 0.5-12.3 17 Foster Creek 8.1 6.6 10.1 5.5 27.7 26.6 17.9 15.5 a 9.2 3.7-29.7 17 St Helena Sound 2.8 1.3 5.2 10.2 2.7 6.2 8.4 4.7 a 4.0 0.3-12.3 16 Ashepoo River 1.0 6.5 8.3 8.9 1.0 10.3 3.8 5.7 a 5.5 0.3-15.7 12

Zinc Charleston harbour 18.1 17.3 30.0 24.5 19.0 18.4 22.5 21.4 a 5.9 14.8-35.8 21 Foster Creek 56.3 57.0 56.1 79.9 46.2 46.2 85.0 61.7 a 19.0 44.8-112.7 20 St. Helena Sound 16.2 16.3 25.3 40.8 8.7 16.4 29.3 20.9 a 1 3 . 1 5.5-47.6 20 Ashepoo River 4.3 27.0 17.1 14.6 6.1 19.3 15.8 14.2 a 1 4 . 1 4.3-49.0 13

*Mean values for each metal with the same letter were accepted to be equal (p >0.05). 1-Mean, standard deviation, and range of all samples analysed for each station.

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Volume 15/Number 4/April 1984

had more Cu and Zn than oysters from the St Helena Sound. Foster Creek oysters also contained more Zn than those from the harbour. The harbour oyster had more Cu and Zn than those from the St Helena Sound. Foster Creek sediment had more Cu, Pb and Zn than sediments from the Harbor, St Helena Sound and the Ashepoo River. Also, Foster Creek sediment had more Cd than that from the Ashepoo River, and harbour sediment had more Cu than the sediment from the Ashepoo River.

The data indicate generally that crab muscle and oyster meats obtained from locations nearest domestic and industrial activities have the highest Cu and Zn concentra- tions. Cu and Zn concentrations are comparable to these two metals reported for crab and oyster in estuaries and bays located in other geographic regions of the Atlantic and Gulf coasts of the United States (Kopfler & Mayer, 1973; Hall et al., 1978, excluding oyster data from the New York Bight). Temporal variations of metals in crab and oyster suggest that this variability should be considered when interpreting the data.

The author thanks Horace Cooper and Kevin Beck for their technical assistance and Lysander Ng for statistical analysis. The author is also grateful to John Babinchak for his cooperation during sample collection. Reference to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA.

MARION SANDERS National Marine Fisheries Service, NOAA, Southeast Fisheries Center, Charleston Laboratory, Charleston, SC29312-0607, USA

Emmel, R. H., Soter, J. J. & Stux, D. L. (1977). Atomic absorption method manual, Vol. l, Standard condition for flame operation. Instrumentation Laboratory Inc., Analytic Instrument Division, Wilmington, MA.

Frazier, J. M. (1975). The dynamics of metals in the American oyster, Crassotrea virginica I. Seaonal effects. Chesapeake Sci., 16, 162-17 I.

Gajan, R. J., Caper, S. G., Subjoc, C. A. & Sanders, M. (1982). Deter- mination of lead and cadmium in foods by anodic stripping voltam- metry. J. Assoc. O f f anal. Chem. 65, 970-977.

Hall, R. A., Zook, E. G. & Meaburn, G. M. (1978). National Marine Fisheries Service Survey of trace elements in the Fisheries Resource, NMFS Report SSRF-721.

Hutcheson, M. S. (1974). The effect of temperature and salinity on cadmium uptake by the blue crab, Callinectes sapidus, Chesapeake Sck, 15, 237-241.

Kopfler, F. C. & Mayer, J. (1973). Concentrations of five trace metals in the waters and oysters (Crassostrea virginica) of Mobile Bay, Alabama. Proc. nat. Shellfish Ass., 63, 27-34.

Moore, D. J. (1971). The uptake and concentration of fluoride by the blue crab, Callinectessapidus. Chesapeake Sci., 12, 1-13.

Simpson, J. H. (1979). Dredge spoils and sewage in the trace metal budget of estuarine and coastal water. EPA Report 600/3-79-029.

Marine Pollution Bulletin, Vol. 15, NO. 4. pp. 161-162, 1984 Printed in Great Britain

S/r, Your Editorial "Who makes the Decisions, Anyway?" (Marine Pollution Bulletin, 14, 365-366, 1983), and the article by A. H. Pickaver entitled "Why Environmental Groups?" (Marine Pollution Bulletin, 14, 6-11, 1983) have just come to my attention. Most of what Pickaver says is in accord with my own experience in international affairs, with respect both to pollution and to the management of marine living resources. In one respect, however, he gives a seriously misleading account of recent events regarding the Inter- national Whaiing Commission. He writes that "undercover work i s . . . bringing more non-whaling nations into the IWC in order to obtain the necessary three-quarters majority that will ensure the environmentalists' dream-come-true-a moratorium on all whaling" [my emphasis]. In fact the effort by environmental groups and environmentally sensi- tive countries has been to achieve a moratorium on commercial whaling; virtually all of them agree that subsist- ence whaling by aboriginal peoples could continue so long as the very existence of the resource is not threatened, and that is not official IWC policy. But, while some countries have perhaps joined the IWC primarily to cast a vote for a moratorium, o the rs - I think m o s t - of the new members have joined for a more important reason. That was to emphasize that the conservation and future use of the living resources of the sea, especially those inhabiting the high seas and that are highly migratory, are the concern of all nations, not merely those 'developed' nations that got in there first

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and, in the process of exploitation, deeply depleted those resources. These less developed countries, with other new members such as Finland and West Germany, joined the 'reformed' ex-whalers in the IWC, and even one of the current whalers, in finally getting through the moratorium and a number of other conservative management decisions. There are very important lessons to be drawn from this process for other attempts, internationally, to bring misuse of the marine environment and its resources under control.

As for your Editorial, although you recognize in your last paragraph the deviousness of the UK Government, you reserve most of your harsh judgements for environmental voluntary groups. I consider this quite unjustified. For example, you open with the comment that there is not much point in scientific investigation if the advice is to be ignored or decisions based on it are frustrated, and your illustration is of Greenpeace hindering "perfectly legal" dumping. Apart from the emotive bias in "perfectly" and its redundancy- as elsewhere in the Edi tor ia l - why pick on Greenpeace? Far more often it is governments that hinder the reaching or application of decisions that would be based on advice they don't like. There is also usually sufficient uncertainty about the scientific issues, and dissent among scientists, for authorities to be able to choose the elements of the advice that happen to suit them. When, as in this country, there is a tradition of withholding information from the public and of government leaning towards indus- trial interests, the odds are indeed stacked against the public and the longer-term interests, at the national level.

At the international level, another factor comes into play. This is the virtually universal escape clauses in treaties which allow any country not liking a decision by an international

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