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

硒（Se）是一种无机污染物，目前在北美具有很高的重要性。一些主要的工业过程，包括燃煤电厂、炼油厂和各种类型的采矿作业（如煤、金和铀），会意外地排放到水生环境中。在一些接收环境中，人们担心硒排放产生的生态毒理学影响，导致目前许多工业赞助的环境硒研究。与此同时，美国环境保护署和加拿大环境部正在重新评估目前的环境硒标准。对硒排放增加的主要担忧是，它在水生生物中生物积累，并可能导致水鸟和捕食性鱼类（如鸭子和鳟鱼）的生殖影响（例如生育力降低、死产和后代畸形），这可能最终危及整个当地种群的生存。有机硒通常被认为是硒的生物积累和生态毒性，但从未在生物外进行过决定性的测量。拟议的研究计划的目标是一劳永逸地确定，在生物地球化学模型和生态毒理学评估中经常假设的某些离散有机硒物种和有机硒化合物群，是否确实存在于环境水和沉积物中（如果存在，则以何种相对和绝对浓度存在）。为此，将允许藻类在受控条件下与硒相互作用，并确定硒在代谢和腐烂过程中释放的形式。

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.