Mercury in lake sediment cores of eastern and northern Canada

Mercury in lake sediment cores of eastern and northern CanadaRecent and historical deposition of mercury (Hg) are examined over a broad geographic area from southwestern Northwest Territories to Labrador and from the U.S. Northeast to northern Ellesmere Island using dated sediment cores from 50 lakes (18 in midlatitudes (41-50 degrees North), 14 subarctic (51-64 degrees North) and 18 in the Arctic (65-83 degrees North)). Objectives were to quantify latitudinal and longitudinal trends of anthropogenic mercury deposition in eastern and northern North America, to investigate variations in mercury deposition, to examine relationships with lake area, catchment\/lake area ratio and sedimentation rates, and to compare results with model predictions.

Distinct increases of mercury over time were observed in 76% of Arctic, 86% of subarctic and 100% of midlatitude cores. Subsurface maxima in mercury depositional fluxes were observed in only 28% of midlatitude lakes and 18% of arctic lakes, indicating little recent reduction of inputs. Anthropogenic mercury fluxes adjusted for sediment focusing and changes in sedimentation rates were negatively correlated with latitude. The latitudinal trend for anthropogenic mercury fluxes adjusted for sediment focusing and changes in sedimentation rates values showed excellent agreement with predictions of the global\/regional atmospheric heavy metal (mercury) model (GRAHM) for the geographic location of each lake. The results are consistent with a scenario of slow atmospheric oxidation of mercury, and slow deposition of reactive mercury emissions, declining with increasing latitude away from emission sources in the midlatitudes, and support the view that there are significant anthropogenic mercury inputs in the Arctic.


Metadata

External resources

Link Name Protocol
Scientific Publication - Spatial Trends and Historical Deposition of Mercury in Eastern and Northern Canada Inferred from Lake Sediment Cores
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Scientific Publication - Bathymetry and Sediment Geochemistry of Lake Hazen (Quttinirpaaq National Park, Ellesmere Island, Nunavut)
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Scientific Publication - Deposition and Cycling of Sulfur Controls Mercury Accumulation in Isle Royale Fish
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Mercury in lake sediment cores of eastern and northern Canada
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[   ]56fbf46f-2883-410c-a830-2836bcfd29f0.xml2021-04-26 02:57 80KUnknown item
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[Comma separated]NCP_ArcticSedimentCores_Contaminant_Concentrations_EN_FR.csv2021-04-26 02:57 127KComma separated
[Comma separated]NCP_ArcticSedimentCores_LakeInformation_EN_FR.csv2021-04-26 02:57 22KComma separated
[Comma separated]NCP_ArcticSedimentCores_Mercury_FluxInformation_EN_FR.csv2021-04-26 02:57 20KComma separated
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