Effects of Chlorobrominated and Chlorinated Cooling Waters on Estuarine Organisms

Toxicities of chlorobrominated and chlorinated cooling waters to selected estuarine food-chain organisms were investigated during an on-site power plant study. Survivals were similar among juvenile Atlantic menhaden (Brevoortia tyrannus) and spot (Leiostomus xanthurus) after exposures to BrCl- and ${\rm Cl}_{2}\text{-treated}$ condenser effluents. Juvenile American oysters (Crassostrea virginica) and brackish water clams (Rangia cuneata) had no halogen-attributable mortalities after 15-day exposures. Similar survival reductions were recorded for copepods (Acartia tonsa) subjected to BrCl or ${\rm Cl}_{2}$ residuals (< 0.100 mg/l) for 24 hours. Eductions in oxygen evolution (77 to 388%) and carbon-fixation (40 to 71%) rates and increased respiration rates (56 to 1 276%) of entrained phytoplankton were recorded from both chlorobrominated and chlorinated samples. BrCl and ${\rm Cl}_{2}$ residuals thus appear to have similar toxicities to estuarine organisms.