WASHINGTON — In its annual assessment of the nation's waters, the Environmental Protection Agency on Tuesday said improved sewage treatment is paying off in cleaner lakes, streams and estuaries.
But the agency said toxic contamination, pesticide and soil runoff, loss of wetlands and contamination of groundwater remain significant problems.
The agency said "water quality in the United States has improved significantly in the past 15 years, despite population and industrial growth."
In Lake Erie, said EPA spokesman Dave Ryan, phosphorus and mercury have declined and the number of walleyed pike has risen.
In the Connecticut River, Ryan said, declining pollution and installation of fish ladders has led to the return of shad and Atlantic salmon.