Selenium

GENERAL INFORMATION
Selenium is a metal found in natural deposits such as ores containing other elements. The greatest use of selenium compounds is in electronic and photocopier components, but they are also widely used in glass, pigments, rubber, metal alloys, textiles, petroleum, medical therapeutic agents, and photographic emulsions. The major sources of selenium in drinking water are discharge from petroleum and metal refineries; erosion of natural deposits; and discharge from mines.

HEALTH EFFECTS
Selenium has both beneficial and harmful effects. Low doses of selenium are needed to maintain good health. However, exposure to high levels can cause adverse health effects. Some people who drink water containing selenium well in excess of the maximum contaminant level (MCL) for many years could experience hair or fingernail losses, numbness in fingers or toes, or problems with their circulation.