Use In the glass industry as a decolorizing agent. Selenium is used extensively in the manufacture and production of glass, pigments, rubber, metal alloys, textiles, petroleum, medical therapeutic agents, and photographic emulsions. 3 Density 4.26-4.81 Sensitivity Data Elemental selenium dusts produce respiratory tract irritation manifested by nasal discharge, loss of smell, epistaxis, and cough. Environmental Fate There are no true deposits of selenium anywhere and it cannot economically be recovered from the earth directly. Present in the major oceans and in inland waters resulting in the presence of selenium in drinking water.
Selenium accompanies sulfur in volcanic effluents.
Soils in the neighborhood of volcanos tend to have enriched amounts of selenium. The earth's crust is said to have an average selenium concentration of 0.03 of 0.08 ppm. Selenium is the most strongly enriched element in coal, being present as an organoselenium compound, a chelated species, or as an adsorbed element. Various industries discharge small amounts of selenium into the air, water, and soil of the immediate vicinity. The forms of selenium in soil depend on soil pH and redox.