"Selenium is an essential nutrient, but excess amounts can be dangerous to wildlife and people. Now the U.S. Environmental Protection Agency is preparing a new regulation that would require more than 600 coal-fired power plants to clean up -- perhaps even eliminate -- wastewater discharged into lakes, rivers and other waterways. The national standards would replace a patchwork of state regulations that EPA officials say are too lax to protect fish and wildlife from toxic metals and other elements, particularly selenium, in the plants' wastewater. Some states allow the plants to emit selenium at levels hundreds of times higher than EPA's water-quality standards, while others don't even require monitoring for it. "Sarah Coefield reports for Environmental Health News December 4, 2009.