Interpreting Selenium Concentrations

Abstract

The importance of selenium as an environmental contaminant has gained widespread attention among field biologists, scientists, and natural resource managers during the past two decades. Although the basic toxicological symptoms and the nutritional paradox of selenium (nutritionally required in small amounts but highly toxic in slightly greater amounts) have been known for many years Draize and Beath 1935 Ellis et al. 1937 Rosenfeld and Beath 1946 Hartley and Grant 1961), it was not until the late 1970s and early 1980s that the potential for widespread contamination of aquatic ecosystems due to human activities was recognized Andren et al. 1975 Cherry and Guthrie 1977 Evans et al. 1980 National Research Council 1980 Braunstein et al. 1981. As recently as 1970, selenium was being called the “unknown pollutant” in the context of what was known about its cycling and toxicity in the aquatic environment Copeland 1970. Yet, within a few years, several major cases of selenium contamination would take place and reveal the need to interpret selenium concentrations in a variety of aquatic habitats. Two examples were the pollution event at Belews Lake, NC, in which an entire fish community (19 species) was eliminated due to selenium in wastewater from a coal-fired power plant (Cumbie and Van Horn 1978Garrett and Inman 1984 Sorensen et al. 1984Lemly 1985a, 1993, 1997 Sorensen 1986, and the episode at Kesterson National Wildlife Refuge, CA, in which thousands of fish and waterbirds were poisoned by selenium in agricultural irrigation drainage (Marshall 1985 Hoffman et al. 1986 Ohlendorf et al. 1986, 1988 Saiki 1986a, 1986b Saiki and Lowe 1987).