Selenium: Introduction
Selenium is a naturally occurring element and an important micronutrient essential for all living organisms. Selenium is also used in many commercial applications including glass decolorizing, metallurgical additives, machining of ferrous and nonferrous alloys, pigments, copier photoreceptors, and in semiconductor and photocell industries.
Although selenium is essential, large concentrations can be toxic, particularly to aquatic wildlife. Human activities such as coal mining, industrial processing, agricultural runoff and leaching of natural soluble selenium can concentrate selenium in excess of the regulatory limits of 5 micrograms per liter (µg/L) and affect wetland habits. The USGS Energy Resources Program researches the geologic location, extent and distribution, and environmental affects on human health and the landscape and provides this information to decision-makers.
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