Scientists said the fish are having problems reproducing and are worried about a population decline. The greatest concentration of the drug is found at the lakeshore, but trace amounts have been found as far as 2 miles out. “There's also a problem with people dumping the medications down the toilet. It's probably not as big of a problem as people excreting the medication,” Klaper said. Milwaukee Metropolitan Sewerage District spokesman Bill Graffin said he agrees it's a problem.