Chemical contamination of groundwater has become increasingly prevalent in the U.S. Once thought to be safe from pollution, the underground aquifers that supply drinking water to about half of the U.S. population are now known to be vulnerable to contamination from leaking landfills, waste lagoons, underground storage tanks, improper use of agricultural chemicals, and various industrial operations. Manufactured chemical compounds, including industrial degreasers and solvents, as well as gasoline, pesticides and fertilizers (in all, over 700 synthetic organic chemicals) have seeped down through the soil to the aquifers and been detected in ground water. Nearly every state has identified cases of contamination serious enough to require closing of some public or private supply wells.
