News release: “In a new study conducted by the U.S. Geological Survey (USGS), every single fish tested from 291 freshwater streams across the United States was found to be contaminated with mercury. “This study shows just how widespread mercury pollution has become in our air, watersheds and many of our fish in freshwater streams,” said Interior Secretary Ken Salazar. Mercury is a potent neurotoxin that builds up in the food chain at ever higher concentrations in predators such as large fish and humans. It is especially damaging to the developing nervous systems of fetuses and children, but can have severe effects on adults, as well. The pollutant enters the environment almost wholly as atmospheric emissions from industrial processes, primarily the burning of coal for electricity. It then spreads across the plant and settles back to the surface, eventually concentrating in rivers, lakes and oceans, where it enters the aquatic food chain.”