Introduction into the environment of elements (such as arsenic, cadmium, lead, and mercury) which have a deleterious effect on living organisms when found naturally in only minor amounts (concentrations less than 1.0 milligram per liter) in water or sediment.
Trace elements are inorganic chemicals occurring in small amounts in nature. This web site of the National Water Quality Assessment links to U.S. data, publications, news, and other sites on trace metals, metalloids and radionuclides in water.
Homepage for the Toxic Substances Hydrology Program, which provides scientific information on contaminated sites and on human and environmental health. Links to news, topical information, investigations, meetings, publications, and photos.
Arsenic is a naturally occurring element in rocks, soils, and the waters in contact with them. It is found in ground water as the result of minerals dissolving from weathered rocks and soils. This site links to data, maps, and more.
Information on arsenic in United States ground water largely as a result of minerals dissolving from weathered rocks and soils. Includes links to publications, data, maps, and links to other sites with information on arsenic.
Maps and text (Word or PDF format) and database (Excel or HTML format) for bedrock, forest floor, and mineral soil sampling in Voyageurs National Park, Minnesota to establish the background and baseline geochemistry and terrestrial mercury sources.
Collection of six short papers related to the mercury geochemical society, the study of mercury in coal, concentrations in sediment, soil, water, and fish collected near mercury and gold mines, and volanic emissions of mercury.
Home page on hydrology studies on mercury, the most common contaminant of aquatic ecosystems, with links to general information, research team projects and data.
Fact sheet on mercury and the environment, including toxic effects, risk to people and wildlife, sources of mercury, environments where methylmercury is a problem, and mercury contamination.
Overview of three research programs including determining levels of mercury at selected sites in water, sediment and fish, mercury emissions into the atmosphere, and mercury cycling in the Everglades National Park, Florida.
U.S. Department of the Interior |
U.S. Geological Survey