| Abstract: |
Selenium is a trace element that is normally present in surface waters at concentrations of about 0.1 - 0.3 parts-per-billion; Lemly, 1985a. In slightly greater amounts, i. e., l-5 ppb, it can bioaccumulate in aquatic food chains and become a concentrated dietary source of selenium that is highly toxic to fish and wildlife (Lemly and Smith, 1987; Lemly, 1993a). Dietary selenium is passed from parents to off-spring in the eggs, where it can be teratogenic to developing embryos and cause complete reproductive failure (Gillespie and Baumann, 1986; Heinz et al. , 1987, 1989; Coyle et al. , 1993 ; Lemly, 1993b). This scenario of poisoning has occurred in reservoirs contaminated by selenium leached from fly-ash at coal-fired electric generating stations in the eastern U. S. (Garrett and Inmann, 1984; Lemly, 1985b). and in wetlands used to dispose subsurface agricultural irrigation drainage in the western U.S. (Lemly, et al., 1993; Lemly 1994a, 1994b). Public health may also be threatened if humans consume selenium-contaminated fish and wildlife (Fan et al., 1988). |
