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Aquatic Ecosystem Exposure Associated with Atmospheric Mercury Deposition: Importance of Watershed and Water Body Hot Spots and Hot Moments
Citation:
KNIGHTES, C. D. AND H. E. GOLDEN. Aquatic Ecosystem Exposure Associated with Atmospheric Mercury Deposition: Importance of Watershed and Water Body Hot Spots and Hot Moments. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 15 - 19, 2008.
Impact/Purpose:
Scientific presentation at the American Geophysical Union meeting.
Description:
Atmospheric deposition of divalent mercury (Hg(II)) is often the primary driving force for mercury contamination in fish tissue, resulting in mercury exposure to wildlife and humans. Transport and transformation of the deposited mercury into the environmentally relevant form, methylmercury (MeHg), proceeds at different rates largely regulated by physical characteristics such as watershed land use types and water body hydraulic residence times and water body chemistry, such as pH and trophic status. To fully represent mercury exposure in aquatic ecosystems, we must couple watershed models with water body models and explore where, why, and when hot spots and hot moments of transformation and transport occur. Here we use a spatially resolved, dynamic multi-media modeling framework to simulate mercury species cycling over time for the different river reaches and watersheds within the Cape Fear River Basin, NC, USA. Through these simulations we investigate the importance of specific watershed and surface water system characteristics in simulating MeHg exposure concentrations. Because the models are dynamic and spatially-distributed, we are able to resolve and investigate the importance of different spatial and temporal factors in transporting and transforming deposited mercury.