Meromictic Investigations for Northern Ecosystem Sustainability (MINES)

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Meromictic or incomplete mixing of the water column can occur in lakes receiving water with high concentrations of sulphates from mine discharges. These elevated sulphate waters are more dense than background water and sink to the bottom of the lakes. This density difference stops normal lake turnover with corresponding lowering of oxygen in the bottom waters, release of metals and a loss of habitat for fish. Build up of toxic hydrogen sulphide can also occur in the sediment restricting colonization by benthic rganisms. Mining companies have received increased attention from regulatory agencies to prevent or rehabilitate meromictic conditions. However the understanding of the formation of meromixis and its effect on the biota in natural lakes is limited. Consequently, a research partnership between Barrick-Hemlo and First Quantum Mining Ltd., both with meromictic lakes, and Lakehead University has been established to study this situation. The research conducts detailed chemical and physical sampling of the water bodies as well as for the benthic, pelagic and macrophyte communities present. Toxicology and bioaccumulation of contaminants are assessed and related to the possibility of re-establishing brook trout in one of the lakes. The research develops computer models that quantify the water balance and chemical mass transfer of contaminants in the impacted lakes,determines the causes of changes to the biological communities and develops prevention and remediation scenarios for the impacted lakes. The outcome are tools that can be used by mining companies to predict how and when to correct the occurrence of meromictic conditions and return the lakes to a normal holomictic condition. The research will involve the integration of field techniques including applicable sampling methods for the collection of aquatic community parameters with lab techniques using autoanalyzers, titrators, digesters, ion chromatography and spectroscopic investigations. In addition to producing long-term sustainability for mining operations that meet acceptable environmental standards, the research will provide training for fivegraduate and two undergraduate students for the mining sector in Canada's north.