The objective of this study was to determine the dominant biogeochemical controls on mercury partitioning in super-permafrost groundwater at Truelove Lowland, Devon Island, Nunavut. Mercury partitioning in snow, ephemeral standing water, and super-permafrost groundwater was investigated. <p>Results indicate that partitioning differs between matrices, and that particulate mercury is spatially and temporally dynamic in Truelove Lowland groundwater. Particulate mercury in groundwater was 73 % of total mercury, while snow had only 22 % particulate mercury. Particulate mercury in groundwater rose by over 20 % from Julian day 181 to 189, and decreased slightly on Julian day 191. No single geochemical parameter was a good predictor of particulate mercury concentrations. To expand upon the findings of the field study a laboratory microcosm study was conducted to determine whether certain biogeochemical processes influence mercury partitioning in super-permafrost groundwater. Particulate mercury in the dissimilatory iron reducing bacteria inhibited microcosm was 61 % of total mercury, approximately 18 % lower than in all other treatments. Iron (III) concentrations had a positive correlation with particulate mercury while chloride concentrations had a negative correlation with particulate mercury. Sulfate reducing bacteria were not found to influence mercury partitioning.

The objective of this study was to determine the dominant biogeochemical controls on mercury partitioning in super-permafrost groundwater at Truelove Lowland, Devon Island, Nunavut. Mercury partitioning in snow, ephemeral standing water, and super-permafrost groundwater was investigated. <p>Results indicate that partitioning differs between matrices, and that particulate mercury is spatially and temporally dynamic in Truelove Lowland groundwater. Particulate mercury in groundwater was 73 % of total mercury, while snow had only 22 % particulate mercury. Particulate mercury in groundwater rose by over 20 % from Julian day 181 to 189, and decreased slightly on Julian day 191. No single geochemical parameter was a good predictor of particulate mercury concentrations. To expand upon the findings of the field study a laboratory microcosm study was conducted to determine whether certain biogeochemical processes influence mercury partitioning in super-permafrost groundwater. Particulate mercury in the dissimilatory iron reducing bacteria inhibited microcosm was 61 % of total mercury, approximately 18 % lower than in all other treatments. Iron (III) concentrations had a positive correlation with particulate mercury while chloride concentrations had a negative correlation with particulate mercury. Sulfate reducing bacteria were not found to influence mercury partitioning.