SS3.17 Global Mercury Cycling: From Natural to Anthropogenic Sources
Date: Tuesday, June 11, 2002
Time: 3:15:00 PM
Location: Carson C
 
Planas, D , GRIL-Universite du Quebec a Montreal, Montreal, Canada, planas.dolores@uqam.ca
Desrosiers, M, , GRIL-Universite du Quebec a Montreal, Montreal, Canada, melanied@dsuper.net
Beyruth, Z, , FAPESP/GEOTOP-Universite du Quebec a Montreal, Montreal, Canada, zbeyruth@videotron.ca
Mucci, A, , GEOTOP - McGill University, Montreal, Canada, alm@eps.mcgill.ca
 
WARTERSHED CHARACTERISTICS AND METHYLMERCURY / TOTAL MERCURY ACCUMULATION ON LAKE LITTORAL COMMUNITIES
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Mercury (Hg) inputs to aquatic ecosystems are mediated by physical, chemical and biological processes that occur at the watershed scale. Dissolved organic carbon (DOC) seems to be an important vector of Hg to aquatic ecosystems. DOC loading to lakes depends on watershed morphometry as well as soil type and landscape mosaic (wetlands, clear cutting, forest age...) The aim of this study was to investigate the relationship between watershed spatial characteristics and mercury accumulation in littoral communities. The study was carried out in 24 boreal Canadian Shield lakes. Periphyton was sampled on natural substrates (rock) and macro-benthos were collected nearby. The THg and MeHg levels were measured by cold-vapour atomic fluorescence techniques. Inter-lake variability in THg and MeHg levels in periphyton and benthos was high. Watershed characteristics that could explain this variability will be discussed.