Publications

'Ground-water recharge' broadly describes the addition of water to the ground-water system. Most water recharging the ground-water system moves relatively rapidly to surface-water bodies and sustains streamflow, lake levels, and wetlands. Over the long term, recharge is generally balanced by discharge to surface waters, to plants, and to deeper parts of the ground-water system. However...

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A mathematically linked mercury transport, speciation, kinetic, and simple biotic uptake (BIOTRANSPEC) model has been developed. An extension of the metal transport and speciation (TRANSPEC) model, BIOTRANSPEC estimates the fate and biotic uptake of inorganic (Hg(II)), elemental (Hg(0)) and organic (MeHg) forms of mercury and their species in the dissolved, colloidal (e.g., dissolved...

No abstract available.

As part of the U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Program, two Source Water-Quality Assessments (SWQAs) were conducted during 2004–05 in unconfined parts of the glacial aquifer system and in unconfined parts of the Prairie du Chien-Jordan aquifer in the Greater Twin Cities metropolitan area of Minnesota and Wisconsin. SWQAs are two-phased sampling...

The history of overbank sedimentation in the vicinity of Halfway Creek Marsh near La Crosse, Wis., was examined during 2005?06 by the U.S. Geological Survey and University of Wisconsin?Madison as part of a broader study of sediment and nutrient loadings to the Upper Mississippi River bottomlands by the U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, and U.S...

The St. Clair River/Lake St. Clair waterway forms an international boundary between the United States and Canada. The waters of the area are an important part of the cultural heritage of the area and serves as an important water-supply and power-generating resource; the waterway also supports an economy based largely on recreation, agriculture, and manufacturing. This report was...

Speciated measurements of atmospheric mercury plumes were obtained at an industrially impacted residential area of East St. Louis, IL. These plumes were found to result in extremely high mercury concentrations at ground level that were composed of a wide distribution of mercury species. Ground level concentrations as high as 235 ng m-3 for elemental mercury (Hg 0) and 38 300 pg m-3 for...

Methylmercury contamination of fisheries from centuries of industrial atmospheric emissions negatively impacts humans and wild-life worldwide. The response of fish methylmercury concentrations to changes in mercury deposition has been difficult to establish because sediments/soils contain large pools of historical contamination, and many factors in addition to deposition affect fish...

Mercury contamination in the environment is a global concern, especially in areas with abundant wetlands, such as south Florida. As the causal factors of this concern improve, scientists find that many factors that do not necessarily affect mercury concentrations, such as flooding and drying cycles, or changes to carbon and sulfate loading, can profoundly affect net mercury toxicity...

Isotopically enriched Hg (90% 202Hg) was added to a small lake in Ontario, Canada, at a rate equivalent to approximately threefold the annual direct atmospheric deposition rate that is typical of the northeastern United States. The Hg spike was thoroughly mixed into the epilimnion in nine separate events at two-week intervals throughout the summer growing season for three consecutive...