WASHINGTON — Despite improvements, nearly four of every 10 lakes, rivers and estuaries remain too polluted to allow fishing, swimming or other aquatic uses at some time of the year, the Environmental Protection Agency reported Thursday.
About 37% of the country's lakes and estuaries and 36% of its rivers have levels of pollution that make them "not clean enough to meet basic uses," the report said.
The EPA said polluted runoff from agriculture, industrial activities and urban growth are the primary causes for the pollution. It said sewage, disease-causing bacteria, fertilizer, toxic metals, oil and grease are among the most frequent pollutants.
The report said the findings are similar to results outlined in the agency's last study three years ago.
"We are holding our own in controlling water pollution, but we need to make progress," EPA Administrator Carol Browner said.
High levels of nutrients, such as phosphates and nitrates used in fertilizers, are the most widely found pollutants in lakes and estuaries. They often create "a chain of impacts that lead to excessive algae and weed growth, kill fish and cause foul odors in waterways, the report said.