ABSTRACT
Large open-cycle, once-through cooling electric generating stations are sited on estuaries or other coastal systems because they require substantial quantities of condenser cooling water. Finfish and other nonentrainable organisms are frequently impinged on intake screens and occasionally on trash racks during plant operation. Smaller organisms, such as the early life history stages of fish and invertebrates (i.e., eggs and larvae), pass through the condenser system and are exposed to thermal, chemical, and mechanical stresses that lower their survival rates. Initial concerns regarding the impacts of power plant cooling systems on the aquatic environment centered on thermal loading. Chlorine is used in coastal power plants to control biofouling of the cooling water circuit. A byproduct of power plant chlorination is the propensity of chlorine to form toxic residual organic compounds (chloramines) which can be hazardous to many aquatic organisms. The absolute number of organisms lost in large power plants due to entrainment mortality is usually extremely high.
