Fish with potentially harmful levels of mercury and other chemicals were found in about half of U.S. lakes and reservoirs in a three-year study, the Environmental Protection Agency said Tuesday.
Women of child-bearing age and children should limit how much fish they eat, and states should step up efforts to reduce mercury pollution, the EPA said. Mercury can cause neurological damage and birth defects.
The EPA study of 500 lakes was conducted from 2000 to 2003.
Burning coal and other fossil fuels account for almost half of man-made mercury emissions in the U.S., which contribute significantly to mercury in water, the EPA said.
Airborne mercury emissions decreased by 58% from 1990 through 2005.