W4 AM Environmental Fate of Mercury
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in Ballroom 4

(LEA-1116-298353) Mercury Cycling in a Wetland Dominated Ecosystem: A Multidisciplinary Study of Kejimkujik Park Nova Scotia.

Lean, D.R.¹, O'Driscoll, N.², Rencz, A.³, ¹ University of Ottawa, Ottawa, Ontario, Canada² University of Montreal, Montreal, Quebec, Canada³ Geological Survery of Canada, Ottawa, Ontario, Canada

ABSTRACT- The motivation for this project was the alarming levels of mercury in biota in Kejimkujik Park, Nova Scotia, Canada. Specifically, the high levels of mercury in both fish tissue and loon blood. This project was a unique opportunity to bring together researchers to investigate this multidisciplinary environmental problem. The multidisciplinary research approach clearly identifies several major findings related to Hg cycling: (i) potential mercury inputs to the lakes (wet deposition and geology) are similar to other areas in Canada; (ii) high percentages of wetlands in these lakes contribute to high DOC and as a result of low buffering capacity the pH is low in the associated lake water; (iii) high DOC and low pH are the driving factors behind the levels of Hg in fish; (iv) lithology may have an indirect effect on the Hg cycle through changes to hydrology, wetland formation, and DOC export. Ultimately, we would like to know if levels of Hg in biota would be less if emissions to the atmosphere were reduced. From our work we know that similar levels of deposition will have profoundly different effects in different regions. When Hg(II) falls on sites with the right conditions for efficient methyl mercury formation, contaminated food chains will result. This talk will provide an overview of our research and highlight the main findings of the multidisciplinary group.

Key words: Mercury, Bioaccumulation, Speciation, Fate