There’s bad news for U.S. waterways in the EPA’s latest National Lakes Assessment: nutrient pollution is widespread, with 4 in 10 lakes suffering from too much nitrogen and phosphorus.

Why it matters

Nutrient pollution is one of America’s most widespread and costly environmental and public health challenges. Excess nutrients can cause algae blooms, lower oxygen levels, degraded habitat for fish and other life, and lower water quality for recreation. The assessment also found an algal toxin – microcystin – in 39 percent of lakes but below levels of concern. Low concentrations of the herbicide atrazine were found in 30 percent of lakes.

EPA Deputy Assistant Administrator Joel Beauvais said the assessment provides the agency with information on which it can take action to protection the vital resource. “America’s lakes and reservoirs provide many environmental and public health benefits; we use lakes for drinking water, energy, food and recreation, and our fish, birds, and wildlife depend on lakes for habitat,” said Beauvais.

What's being done

Lake managers can use the new interactive dashboard to evaluate site-specific information and to explore population-level results. Conducted on a five-year basis, future lake surveys will help water resource managers assess broad-scale differences in the data and perform trends analysis. 

Among the steps the EPA is taking to reduce the severity, extent, and impacts of nutrient pollution in U.S. waterways:

  • Overseeing regulatory programs
  • conducting outreach and engaging partners
  • providing technical and programmatic support to states
  • financing nutrient reduction activities
  • conducting research and development.

In September, the EPA called upon states and stakeholders to intensify their efforts to reduce nutrient pollution in collaboration with the agency.    

The assessment is part of a series of National Aquatic Resource Surveys designed to provide information about the condition of water resources in the U.S. The surveys are conducted in partnership with states and tribes to provide national-scale assessments of the nation’s waters. 

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