Mercury
More than a quarter of those fish contained concentrations of mercury exceeding levels set by the Environmental Protection Agency for the protection of people who eat average amounts of fish, the U.S. Geological Survey report said.
More than two-thirds exceeded the EPA-set level of concern for fish-eating mammals.
"This study shows just how widespread mercury pollution has become in our air, watersheds, and many of our fish in freshwater streams," Interior Secretary Ken Salazar said in a statement. The USGS is part of the Interior Department.
The neurotoxin enters the environment chiefly as an air pollutant spewed into the atmosphere by industrial emissions, then falls back to the surface in precipitation and particulate matter carried over long distances.
The main source of atmospheric mercury, according to the EPA, is coal-fired power plants.
Doug
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