Investigation of temporal and spatial distribution, fate and biological effects of selenium in a boreal aquatic ecosystem

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The toxicity of selenium (Se) in aquatic systems, particularly to fishes, is currently one of the most debated and research intensive areas of aquatic ecotoxicology in North America. Metal and coal mining activities in Canada and elsewhere have been shown to cause elevated levels of selenium in aquatic ecosystems receiving their discharges, which can impact the sustainability of fish populations and the integrity of ecosystem structure and function. It is in the interest of Canada's environmental stewardship and scientific leadership to better understand factors influencing exposure and potential toxicological effects of Se in aquatic ecosystems, thereby developing a science-based management and regulatory approach. The overall objective of this three year project is to use an integrative, multidisciplinary approach to investigate temporal and spatial dynamics of the distribution, speciation, fate and effects of Se in a northern (boreal) aquatic ecosystem receiving effluent from a metal mining operation. Using field surveys, field experiments (in situ invertebrate and fish caging studies), mesocosm experiments (multi-trophic studies with partial life-cycle fish bioassays), and laboratory experiments (invertebrate feeding and accumulation studies, studies examining the consequences of larval deformities on performance) we intend to better define the trophic transfer of Se and thresholds for response across abiotic and biotic compartments of an aquatic ecosystem. Using state-of-the science synchrotron technology, we will define the form of Se (speciation) and its transformation across media and biota with the goal of determining relationships between speciation and toxicity. Our results will: 1) further the field of Se ecotoxicology; 2) define conditions of exposure and effects associated with coldwater habitats; 3) assist industry to better understand effects that exist in an effort to move towards sustainable solutions; and 4) develop clear and defensible exposure thresholds for preventing adverse ecological impacts. A study of this level of integration and scope has not been conducted in Canada before and has national and international implications far beyond this specific study site.