Eating fish from America’s streams is becoming increasingly dangerous, according to a new study by the U.S. Geological Survey. After examining almost 300 streams from across the country, scientists concluded that 25% of fish contained dangerous levels of mercury for humans, and more than two-thirds had levels considered unsafe for animals to consume. Areas with some of the worst contamination included the “blackwater” streams in North and South Carolina, Georgia, Florida and Louisiana, as well as streams in undeveloped watersheds in the Northeast and the Upper Midwest.