Our standard field sampling procedure requires that ten 

 replicate baseline samples be collected for trace metal, PCBs and 

 wet/dry weight ratio determinations when the stations were first 

 established. Whenever restocking of the platforms was deemed 

 necessary due to predation, mortality and irretrievable losses of 

 the platform, replicate baseline samples were always obtained. 

 During each monthly sampling period, weather permitting, 

 triplicate samples of eight mussels each were collected. 



Laboratory Procedures 



In the laboratory the mussels were cleaned, measured, 

 examined for infection by the pea crab, Pinnotheres maculatus . 

 then shucked and homogenized. An aliquot of the homogenized 

 sample was weighed (wet weight) and lyophilized using a Virtis 

 Model 10-010 freeze drier. After being dried overnight in the 

 apparatus, the freeze dried tissue was weighed again, and 

 designated as the "dry weight" used in calculating the wet/dry 

 ratio. 



In addition, ten mussels each from Rlr, WLISrN, WLISc and 

 500MW were collected monthly and fixed with one valve cracked in 

 neutral buffered formalin for histological studies. 



Trace Metal Analyses . The protocol for trace metal analyses 

 used in this study was the same as that previously reported 

 (Feng, 1984) . 



Analyses of Polychlorinated Biphenvls . Aroclors 1242, 1254 

 and 1260 in Mvtilus edulis tissues were extracted, concentrated, 

 cleaned and gas chromatographed according to the procedures of 

 Arimoto and Feng (1983a) . In the past, quantification of each 

 Aroclor was accomplished manually. Durinq the current study, 

 quantifications of Aroclors were achieved by employinq an Apple 

 11+ microcomputer equipped with two disk drives, a ADALAB data 

 acquisition/ control card, 128K RAM card and CHROMATOCHART 

 software (Interactive Microware, Inc., State Colleqe, PA). After 

 the injection of the standards, the software computes retention 

 time and actual concentrations for each peak of Aroclors 1242, 

 1254 and 1260 as external standards and the results are stored in 

 the memory. The concentration of PCBs of the injected unknown 

 samples is computed using the stored results of the external 

 standards. A comparison of the results obtained from the manual 

 method with that of the present procedure has shown a deviation 

 of no more than 5%. 



Gas Chromatoaraph/Mass Spectrophotometer Identification of 

 Phthalate Esters . An anomalous peak present in the PCB 

 chromatograms was identified by injecting aliquots of the sample 

 into a HP 5890 qas chromatoqraph equipped with a HP 5870 MSD 

 (Mass Selective Detector) . The detected ion peak was matched 



