are sampled from natural populations at Fox Island (north and south) and 

 Giants Neck. Tissues of both shellfish species are analyzed for 

 concentrations of Fe, Cr, Zn, and Cu. 



In addition to the above required collections, the monitoring 

 program has sampled oysters in holding trays at White Point and oysters 

 growing naturally in the quarry. 



CHRONOLOGY 



Sampling for heavy metals began in September 1971 and results 

 through 1974 are presented in NUSCo (1975). Results from 1972 through 

 1979 are presented in NUSCo (1980) and as Appendix II here. Summaries 

 of results from 1980 and 1981 are found in NUSCo (1982) and as Appendix 

 III here. 



Before discussing these results, it will be useful first to review 

 sampling methods and analytic techniques employed at various times 

 throughout the metals monitoring program; these are summarized in Table 

 1. The only change in the program from 1971 through 1979 involved the 

 frequency with which shellfish were sampled. Originally, mussels and 

 oysters were collected in May and December, but starting in May 1973, 

 they were sampled on the same schedule as seawater. In 1980, changes 

 were made in sampling procedure and analytic protocol. A smaller volume 

 of seawater was collected, a different filter was used to partition 

 soluble and insoluble metal fractions, and pH adjustment was lower. 

 Fewer individuals of shellfish were collected and mussels were no longer 

 taken from White Point. (This site is consistently and incorrectly 

 referred to as Bay Point in tables, but not in text, of metals reports 

 from 1971-1979). Shellfish were depurated for 1-3 days, a procedure not 

 known to be practiced previously and first frozen, then shucked. In 1981, 

 procedures were revised slightly to improve upon the previous year's accuracy 



2 



