SS3.17 Global Mercury Cycling: From Natural to Anthropogenic Sources
Date: Tuesday, June 11, 2002
Time: 11:00:00 AM
Location: Carson C
 
FergusonPR, University of Victoria, Victoria, Canada, prfergus@uvic.ca
Telmer, K, , University of Victoria, Victoria, Canada, ktelmer@uvic.ca
 
LONG-TERM MERCURY ACCUMULATION RATES IN EASTERN CANADIAN LAKE SEDIMENTS – THE HOLOCENE
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Heavy metal pollution can be recorded in environmental archives such as lake sediments, peat bogs, and soils. To evaluate the magnitude of recent inputs of heavy metals such as mercury, knowledge of natural, pre-industrial concentrations is necessary. Sediment cores up to 6 meters in length were obtained from two small lakes located in Kejimkujik National Park, southeastern Nova Scotia, Canada, and mercury concentrations were measured down the entire core, roughly representing the Holocene. Calibrated with the sediment cores, high-resolution seismic reflection profiles allow accurate determination of sediment distribution within the lake and total sediment mass and thickness. Mercury depth profiles reveal systematic shifts in mercury concentration during pre-industrial times that may be related to climate. A precise estimate of lake sediment volume, together with sediment chemistry, is used to construct a mercury accumulation inventory for the last 10,000 years. The inventory and its fluctuations through time are compared to recent inputs.