Nearly 40 percent of U.S. rivers and 45 percent of lakes are polluted to some degree, according to the Environmental Protection Agency's National Water Quality Inventory report.
The report, prepared under Section 305(b) of the Clean Water Act, summarizes water quality reports submitted by all 50 states, the District of Columbia, and five territories; four interstate commissions; and five Indian tribes in 2000.
States focused the majority of their assessment activities on rivers and streams; lakes, ponds, and reservoirs; estuaries; and Great Lakes shoreline. States reported that 61% of assessed river and stream miles, 54% of assessed lake acres, 49% of assessed estuarine square miles, and 22% of assessed Great Lakes shoreline miles fully support the water quality standards evaluated. In the remaining assessed waters, one or more designated uses are impaired.
For this biennial report, states assessed 19% of the nation's total river and stream miles; 43% of its lake, pond, and reservoir acres; 36% of its estuarine square miles; and 92% of Great Lakes shoreline miles.
States assessed very small amounts of ocean and marine resources, wetlands, and ground water. This is due in part to a lack of assessment tools for these resources and, in the case of wetlands, lack of water quality standards. EPA and states are working to improve characterization of these resources.
For the subset of assessed waters identified as impaired, the report presents the leading pollutants and sources of pollution. Across all waterbody types, states and other jurisdictions reported that:
• Siltation, nutrients, bacteria, metals (primarily mercury), and oxygen depleting substances are among the top causes of impairment.
• Pollution from urban and agricultural land that is transported by precipitation and runoff (nonpoint source pollution) is the leading source of impairment.
For many waters, states and other jurisdictions classified the causes and sources of impairment as unknown. Contaminants that impair the water systems include toxic chemicals and waterborne disease-causing pathogens such as viruses, bacteria, and protozoans.
EPA's National Listing of Fish and Wildlife Advisories (NLFWA) database listed 2,838 advisories in effect in 2000; mercury, polychlorinated biphenyls (PCBs), chlordane, dioxins, and dichlorodiphenyltrichloroethane (DDT) (with its byproducts) were responsible for 99% of all the fish consumption advisories in effect.
Ten of 28 coastal states reported prohibited, restricted, or conditionally approved shellfish harvesting in 1,630 square miles of estuarine waters.
Thirty-nine states, tribes, or territories submitted drinking water use data in their reports, and reported that the majority of waterbodies assessed— 86% of river and stream miles and 84% of lake and reservoir acres—are considered to be supporting their drinking water use. Thirteen states and tribes identified 233 sites where contact recreation was restricted at least once during the reporting cycle.
A considerable variety of challenges and recommendations were discussed in the 2000 reports. Many pressing problems seem to have root causes in resource constraints, lack of adequate monitoring data, or lack of coordination among multiple agencies responsible for the same issue areas.
The states and other governing entities recommended that Congress address financial/resource problems so that, at the minimum, basic and priority activities can be implemented. The reports also indicated the need for proper coordination and data integration among different programs to improve efficiency and fully use scarce resources.
The full 2000 National Water Quality Inventory report is available on the Internet at http://www.epa.gov/305b/2000report/.
