The Great Lakes are much cleaner these days than they were just a few decades ago.
Rules to get control of mercury emissions from coal-fired power plants, wastewater discharges and the burning of medical waste have led to a steady drop in mercury contamination of the waters and sediments.
Despite that progress, the levels of mercury in large game fish like lake trout has remained stubbornly high, failing to fall in line with the gradual reduction in pollution. Read more in Great Lakes Now.