INTRODUCTION 



Addition of heavy metal to the Long Island Sound waters is an 

 unavoidable consequence of operating the Millstone Nuclear Power Station 

 (MNPS). The plant's once-through circulating water system is composed 

 in part of (70-30) copper -nickel condenser tubes, which deteriorate 

 through time due to physical (erosion) and chemical (corrosion) processes. 

 Such deterioration releases particulate and dissolved heavy metals into 

 the seawater used for condenser cooling. Another source of metal input 

 to seawater is the service water system. 



Since 1971, Northeast Utilities Service Company (NUSCo) has supported 

 a metals monitoring program designed to determine the contribution of 

 MNPS to heavy metal concentrations in Long Island Sound, and any subsequent 

 bioaccumulation of metals by suspension-feeding bivalves. The intent of 

 the present report is to; 1) recapitulate heavy metals investigations at 

 MNPS through December 1981, 2) evaluate the quality of the information 

 obtained and, 3) suggest improvements in experimental design and analytic 

 technique. It is not the purpose of this report to speculate with regard 

 to potential repercussions of MNPS metal input on Long Island Sound waters 

 or biota. 



PRESENT PROGRAM 



Environmental Technical Specifications (Appendix I) presently require 

 seawater and tissue sampling for metals five times during the year (February, 

 May, July, September, December) . Seawater samples are taken from Giants Neck, 

 Unit 1 Intake, Effluent, and Twotree Island Channel and analyzed for 

 concentrations of Pb, Fe, Cr, Zn, and Cu. Oysters are sampled from holding 

 trays located at the Quarry, Fox Island (north) , and Giants Neck. Mussels 



