作者: David P. Krabbenhoft , John F. DeWild , Mark L. Olson , William G. Brumbaugh , James G. Wiener
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摘要: Mercury (Hg) contamination of aquatic ecosystems is a global problem. However, databases for Hg in environmental samples at regional-to-national scales are few, especially multi-media sampling that include determination methylmercury (MeHg). A national scale pilot study to examine relations total (HgT) and MeHg water, sediment fish was conducted the summer fall 1998. Samples were collected 106 sites from 21 basins across United States, including Alaska Hawaii. The data showed wide ranges concentrations, which expected given diverse array settings, water chemistry, loading represented by these sites. Wetland density single most important basin-scale factor controlling production. At low may also influence production, but high concentrations (>1,000 nanograms per gram; ng/g) there little evidence increasing production with Hg. An atmospheric accumulation index developed differentiating areas where deposition dominant source significant on-site sources. Four along east coast States had greatest methylation efficiency, as reflected MeHg/HgT ratio sediments. Nationwide, sub-basins characterized mixed agriculture forest cover types highest whereas affected mining lowest efficiency. This represents first step toward assessment however, additional needed improve our resolution factors bioaccumulation.