Fish populations of Belews Lake, North Carolina, declined during the period of operation of the Belews Creek Steam Station from 1974 through 1977. Reproduction of fish in the main lake was almost completely absent in 1976 and 1977. A survey of trace elements in water and fish fro.m Belews Lake indicated that selenium concentrations were elevated in Belews Lake water, and that fish in the lake had accumulated unusual amounts of selenium. Fish from a remote area of Belews Lake where normal reproduction took place in 1976 and 1977 had much lower selenium concentrations in their tissues than fish from the main basin. Only trace elements of selenium occur naturally in water, soil, or mineral deposits in the Belews Lake drainage. Selenium entered Belews Lake in soluble form by way of the power plant fly ash sluice water return. Selenium concentrations in Belews Lake water were not high enough to be directly toxic to fish. Uptake by plankton introduced selenium to the food chain where it ultimately reached elevated levels in fish due to bioaccumulation. Selenium is known to interfere with reproduction in animals, and is considered to be the most probable cause of reduced fish reproduction in Belews Lake. The North Carolna Department of Natural Resources and Community Development and Duke Power Company have taken action to reduce inputs of selenium to Belews Lake.
