National Lakes Assessment finds widespread nutrient pollution

The Environmental Protection Agency recently released a new National Lakes Assessment – the first since 2007 – which shows that 40 percent of the country's lakes are experiencing nutrient pollution.

“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,” EPA Deputy Assistant Administrator for Water Joel Beauvais said. “The National Lakes Assessment provides us with valuable information to help protect and restore our lakes across the country.”

Nutrient pollution, wherein lakes have high levels of nitrogen and phosphorus, are detrimental to water quality as they can cause algae blooms and lower oxygen levels. That in turn can lead to aquatic habitat degradation and reduced or eliminated recreational uses of a water body.

In addition to nutrient pollution, the National Lakes Assessment documented algal toxin microcystin in 39 percent of lakes, but at levels that are not of concern. The assessment also found low levels of atrazine, an herbicide, in 30 percent of lakes.

This edition of National Lakes Assessment was more comprehensive than the 2007 edition and includes more and smaller lakes. It also includes an interactive dashboard that lake managers can use to find site-specific information.