Scientists found a significant presence of organic pollution in three Michigan rivers, including the St. Joseph River.
The U.S. Geological Survey sampled water throughout the Great Lakes region from 2010 through 2013.
They found the Rouge, Clinton, and St. Joseph rivers have high levels of pollutants from car exhaust, smokestacks, herbicides and detergents.
Officials say those compounds can cause changes in fish.
The report found 35 percent of samples taken from 57 tributaries in the Great Lakes Basin exceeded
More information can be found in the Detroit Free Press.