Organic selenium species in waters and sediments: Production by algae and fate

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Selenium (Se) is an inorganic contaminant of high current importance in North America. It is discharged accidentally into the aquatic environment from some major industrial processes, including coal-fired power plants, petroleum refineries and various types of mining operations (e.g. coal, gold and uranium). In some receiving environments, there is concern about ecotoxicological effects arising from Se discharges, leading to numerous current industrially-sponsored environmental Se studies. At the same time, the US Environmental Protection Agency and Environment Canada are re-evaluating their current ambient Se criteria. The main concern about elevated Se discharges is that it bioaccumulates in aquatic organisms, and may lead to reproductive effects (e.g. reduced fertility, stillbirth and deformities in offspring) in aquatic birds and predatory fish, such as ducks and trout, which may ultimately endanger the survival of entire local populations. Organic Se species are often invoked in the bioaccumulation and ecotoxicity of Se, but have never been measured conclusively outside of organisms. The goal of the proposed research program is to determine once and for all if certain discrete organo-Se species and groups of organic Se compounds, which are frequently postulated in biogeochemical models and ecotoxicological assessments, actually exist in ambient waters and sediments (and, if so, at what relative and absolute concentrations). For this purpose, algae will be allowed to interact with Se under controlled conditions, and the forms of SE released during metabolism and decay will be determined.