SS4.06 Speciation, Bioavailability, and Impacts of Atmospheric Trace Metals in Aquatic Systems
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
BranfireunBA, University of Toronto, Mississauga, Canada, brian.branfireun@utoronto.ca
Hintelmann, H, , Trent University, Peterborough, Canada, hhintelmann@trentu.ca
Hunt, R, J, US Geological Survey, Middleton, USA, rjhunt@usgs.gov
hurley, J, P, University of Wisconsin - Water Resources Institute, Madison, USA, hurley@wri.wisc.edu
Krabbenhoft, D, P, US Geological Survey, Middleton, USA, dpkrabbe@usgs.gov
Rudd, J, W, Department of Fisheries and Oceans, Winnipeg, Canada, ruddj@dfo-mpo.gc.ca
 
The fate and transport of contemporary mercury deposition in a lake margin boreal wetland: Results from METAALICUS
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As part of the Mercury Experiment to Assess Atmospheric Loadings in Canada and the United States (METAALICUS), we investigated the fate and transport of contemporary mercury deposition in a boreal wetland using an experimentally-applied stable mercury isotope. Inorganic Hg-202 was applied to a wetland plot to determine if: 1) the Hg-202 spike was detectable above the background pool of Hg; 2) the Hg-202 migrated vertically and/or horizontally in peat and pore waters, and; 3) the Hg-202 was methylated. The Hg-202 was easily detected by ICP-MS in both peat and pore waters. Over three months, the Hg spike migrated vertically downwards in excess of 15 cm below the water table and traveled several meters horizontally beyond the experimental plot to the lake margin along the dominant vector of groundwater flow. Importantly, up to 6% of the aqueous Hg-202 was methylated after only one day. These results indicate that inorganic Hg deposited in contemporary atmospheric deposition is readily methylated and transported lakeward by shallow groundwater flow, confirming the important role of wetlands as contributors of Hg to aquatic ecosystems.