"Scientists led by researchers with the U.S. Geological Survey have found an elevated number of cases of skin and liver tumors in white suckers in the Milwaukee, Menomonee and Kinnickinnic rivers — a discovery that suggests more work will be needed to remove contaminants from the waterways.

In a new study, the scientists said they found evidence that some male white suckers sampled in the rivers also had testicular tumors. That was a surprise discovery, and had not often been found in other research projects involving contaminated rivers slated for environmental cleanups, a researcher in the study said.

The exact cause of the tumors is not known, but previous research has suggested that exposure to certain chemicals can cause liver tumors in fish, according to research published this week in the Journal of Fish Diseases."

Lee Bergquist reports for the Milwaukee Journal Sentinel August 26, 2016. [2]