TRACK METAL CONCKNIKAT IONS IN COOLING WATKR lOKKLUKNl' , StAWATfiK , SUSPtlNUEU 

 MATTER, OYSTERS, AND MUSSELS NEAR MILLSTONE POINT, 1983 



INTRODUCTION 



The concentrations of chromium, copper, iron, lead, and zinc in the 

 dissolved and particulate states in seawater and in the cooling water effluent 

 of the Millstone Nuclear Power Station were determined on five occasions during 

 1983, at approximately lU-week intervals. With the exception of lead, 

 concentrations of the same metals were determined in oyster ( Crassostrea 

 virginica ) and mussel ( Mytilus edulis ) tissue, on the same sampling 

 occasions. This 1983 work continues along the lines of a monitoring program 

 for inetals that began in 1971. During tliis same period, geochemical 

 researchers have made large advances in their abilities to accurately measure 

 trace concentrations of metals in seawater and tissue, especially in their 

 ability to control sample contriir-ino"" ion. It is of doubtful value, therefore, 

 to malce strict comparisons between the earliest and the most recent data, but 

 of greater value to compare results of the past few years only. Analytical 

 problems have been greater for seawater determinations than for tissue 

 determinations, such that similar metal levels in oysters and mussels have now 

 been reported for the past several years. The present report is this 

 investigator's second contribution to the monitoring program, although he has 

 conducted special studies of metals in the Millstone Power Station cooling 

 water plume in 1979 and 1980 (Waslenchuk, 1982). 



The sampling locations represent: an environment apparently remote from 

 any power station influence (Giant's Neck); areas proximal to the discharge to 

 Loni; Island Sounil which may be affected to some degree on some occasions by 

 power station cooling waters (Niantic Bay, Twotree Island, Fox Island, White 

 Point), and the undiluted cooling waters themselves (Quarry Cut). Any impacts 

 of power station operations on the metal burdens in Lotig Island Sound waters 

 and mollusc tissues may therefore be revealed as systematic concentration 

 ariomalies (with respect to the remote location), related to proximity to the 

 cooling water plume. 



As shown in a previous detailed study (Waslenchuk, 1982), cooling waters 

 can have metal concentrations higher than ambient Long Island Sound waters, due 

 to corrosion and erosion of condenser pipes. The present study provides 

 results generally consistent with those earlier observations, in that the 

 cooling waters are enriched in copper and zinc. The present study also shows 

 that oysters growing naturally, or deployed in exposure cages, in the quarry 

 (the immediate receiving basin for effluent) have somewhat elevated levels of 

 metals compared to oysters deployed in exposure cages elsewhere in the 

 vicinity. Metal concentrations in oysters and mussels from locations outside 

 the quarry show no discernable relationship to proximity to tlie effluent 

 outfall, in agreement with the results of the 1981 and 1982 monitoring programs 

 (NlJSCo, 1981, 1982 Annual Report). Unlike the past two years' results, 

 however, concentrations are not seen to vary systematically by season, in 

 molluscs outside the quarry. Finally, considering the most distal sampling 

 location (Giant's Neck) to be representative of natural conditions, there is no 

 evidence that the Millstone Power Station effluent causes additional 

 bioaccumulat ion of metals in molluscs near Millstone Point. 



