EPA's selenium revision heads into murky waters

As the US EPA revises its standards for selenium in fresh water, a heated debate rages between government scientists, who say that existing standards must be tightened because selenium contamination is widespread, and industry scientists who believe that it is an environmental oddity. Fish, crustaceans and birds appear to be uniquely sensitive to even modest increases in environmental concentrations of this element. To set new standards, EPA must find a way to take into account an emerging understanding of selenium's complex geochemistry.