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

在北美，硒(Se)是一种非常重要的无机污染物。一些主要工业过程，包括燃煤发电厂、炼油厂和各种类型的采矿作业(如煤、金和铀)，会意外地排放到水环境中。在一些接收环境中，人们对Se排放引起的生态毒理效应感到担忧，导致目前许多工业赞助的环境Se研究。与此同时，美国环保局和加拿大环境局正在重新评估他们目前的环境Se标准。对Se排放增加的主要担忧是，Se在水生生物中生物积累，并可能导致水鸟和捕食性鱼类(如鸭子和鲑鱼)的生殖影响(如生育力下降、死胎和后代畸形)，最终可能危及整个当地种群的生存。有机硒物种经常被引用于硒的生物积累和生态毒性中，但从未在生物体外进行过确凿的测量。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的有机硒物种和有机硒化合物组是否真的存在于周围水域和沉积物中(如果是的话，其相对和绝对浓度是多少)。为此，藻类将被允许在受控条件下与Se相互作用，并将确定在新陈代谢和腐烂期间释放的Se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.