Assessing The Toxic Threat Of Selenium To Fish And Aquatic Birds

Abstract

The importance of selenium as an environmental contaminant has gained widespread attention among scientists, natural resource managers, and water quality regulators in the U.S. during the past two decades. Selenium mobilized from the combustion of coal at electric generating stations has contaminated several major reservoirs, leading to reproductive failure and elimination of entire communities of fish (Cumbie and Van Horn, 1978; Garrett and Inman, 1984; Woock and Summers, 1984; Woock et al., 1985; Lemly, 1985a,1993a). Irrigation of seleniferous soils has produced subsurface drainage that contaminated wetlands and poisoned fish and migratory birds at several locations in the western U.S. (Lemly, 1993b, 1994; Presser, 1994; Presser et al., 1994). The U.S. Environmental Protection Agency and some states have formulated and adopted increasingly restrictive water quality standards for selenium because of these incidents of environmental contamination (NCDEM, 1986; USEPA,1987; CEPA, 1992). Most natural resource management agencies are aware of the toxic threat posed by selenium and many have implemented contaminant monitoring programs to measure selenium concentrations in water, sediments, and aquatic biota. Once these data are collected it is important to conduct an overall evaluation and determine the degree of hazard present in order to identify appropriate management actions. However, few agencies address this information need by performing a comprehensive hazard assessment. There likely are two reasons for this. First, it has been difficult for those conducting the monitoring programs to determine the toxicological significance of selenium residues in aquatic organisms. Taking time to locate, obtain, and interpret the results of selenium toxicity tests for a variety of aquatic species is a difficult task. Fortunately, this type of information synthesis has been done. Guidelines are now available for evaluating selenium in food-chain organisms and fish and wildlife tissues based on current toxicological information (Skorupa and Ohlendorf, 1991; Lemly, 1993; Beyer et al., 1996; Skorupa et al., in press). Interpreting selenium residues, for the most part, is no longer a primary concern.

Citation

Lemly, A. Dennis. 1996. Assessing The Toxic Threat Of Selenium To Fish And Aquatic Birds. Environmental Monitoring and Assessment 43: 19-35, 1996.