Selenium is an essential nutrient at low levels. No Health Advisories have been established for short-term exposures. There is no evidence that selenium has the potential to cause cancer from lifetime exposures in drinking water. Usage Patterns Selenium is used extensively in the manufacture and production of glass, pigments, rubber, metal alloys, textiles, petroleum, medical therapeutic agents, and photographic emulsions.
Selenium dioxide is the most widely used selenium compound in industry.
There are no true deposits of selenium anywhere and it cannot economically be recovered from the earth directly. Soils in the neighborhood of volcanoes tend to have enriched amounts of selenium. Selenium is the most strongly enriched element in coal, being present as an organoselenium compound, a chelated species, or as an adsorbed element. Selenium compounds are released to the air during the combustion of coal and petroleum fuels, and during the smelting and refining of other metals. From 1987 to 1993, according to the Toxics Release Inventory selenium releases to land and water totalled over 1 million lbs., of which about 99 percent was to land.