The U.S. Environmental Protection Agency has released the results of a national assessment showing that nutrient pollution is widespread in the nation’s lakes, with four in 10 lakes suffering from too much nitrogen and phosphorus.
Excess nutrients can cause algae blooms, lower oxygen levels, degraded habitat for fish and other life, and lower water quality for recreation. The National Lakes 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.
“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 Joel Beauvais of the EPA. “The National Lakes Assessment provides us with valuable information to help protect and restore our lakes across the country.”
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.
Locally Dr. Seth Moore, director of biology and environment for the Grand Portage Band of Lake Superior Chippewa Trust Lands is conducting a study of micro-pollutants found in northern Minnesota lakes.
Several years ago Moore conducted a small pilot study, sampling a couple of lakes in Grand Portage. In one lake—a remote lake with no human habitation near it, he said— Moore found pharmaceuticals in the water, which was an alarming surprise.
In the summer of 2017 Moore and his team will sample and assess chemicals from 30 northern Minnesota lakes, looking primarily for pharmaceuticals in fish, water and sediment.
The study will encompass two and one half years and, said Moore, “I can guarantee that we will find some surprising things in this study.”
An earlier National Lakes Assessment was conducted in 2007, but this latest study is expanded to include smaller lakes and increase the number of lakes assessed. 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.
While Dr. Moore’s study will encompass areas in northern Minnesota, he said his first goal would be to assess how eating fish are affecting people in Grand Portage, especially women who are pregnant.
For more information see: www.epa.gov/national-aquatic-resource-surveys/nla.
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