Developing new tools for assessing legacy pollutants and their ecological consequences in lakes near NWT mines

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We will develop novel tools, under the rubric of a new field we are defining as paleoecotoxicology, to assess risk from industrial and residential activities near Yellowknife, NWT. The purpose of this research is to generate important information on the extent and fate of environmental contaminants in the Yellowknife area to inform future land and water management decisions. By combining geochemical and biological approaches (using key toxicological indicators archived in lake sediments), our tools will have applicability in many other regions affected by multiple environmental stressors. The objectives of this research include: (1) to characterize and determine the spatial extent of toxic metals and hydrocarbons produced by local mines and other industrial activities, and identify their toxicological effects on nearby lakes using paleoecotoxicological methods; (2) to determine the mobility and bioaccessibility of arsenic species in the vicinity of Yellowknife and differentiate between the toxic arsenic trioxide derived mainly from stack emissions and the naturally occurring arsenopyrite, which is less toxic; and (3) to identify the sources and causes for methyl mercury 'hotspots' focused near some mining operations, which are contributing to elevated methyl mercury in the region. This research will provide important information on the long term stability, toxicity, and bioaccumulation potential of pollutants in local aquatic environments. We posit that the best risk reduction strategy for environmental pollutants is to reduce exposure by learning about the distribution, dynamics, and fate of pollutants near contaminated sites as we propose to do here. With that knowledge, government agencies can regulate recreational activities, fishing and hunting, and municipal developments as required. Our research will have immediate health benefits to northern residents by identifying areas where there is risk of high contaminant exposure and will inform further remediation strategies in the region.