A clear result of the shellfish portion of the program is that exposure 

 to the plant's discharge waters results in non- toxic bioaccumulation of Cu, 

 and probably other metals, by oysters living naturally in the quarry and 

 those held there in cages. There appear to have been no elevated metal 

 concentrations in oysters nor mussels located in other areas. However, 

 any detailed comparisons between years is essentially meaningless because 

 of changes in methodology through the course of the program. These 

 alterations include the number of individuals analyzed, the sequence of 

 freezing and thawing, depuration, and the reported unit of concentration, 

 i.e., per unit dry or wet weight. In addition, contamination by shucking 

 equipment was demonstrated to have occurred for analyses prior to 1979 

 (NUSCo, 1981). Within year comparisons should be more valid, but are 

 complicated by seasonally-induced gonadotrophic cycles in the shellfish. 



SPECIAL INVESTIGATIONS 



Waslenchuck (1980, 1981) investigated the concentration and fate of 

 Cu, Ni, and Zn in MNPS discharge waters. He found that soluble forms of 

 all three metals and particulate phases of Cu and Zn increased in concentration 

 following the passage of ambient Long Island Sound water through the plant. 

 These increases were approximately 1 yg/1 and 0.5 yg/1 for dissolved and 

 particulate fractions, respectively, and persisted about as long as the 

 temperature anomaly of the discharge waters. Soluble Cu and Zn behaved 

 non-conservatively and were found in excess in the discharge, apparently due 

 to rapid dissolution of unstable metal-rich particulates. 



