EPA OKs Minnesota Standards Changes

The Minnesota Pollution Control Agency (MPCA) announced that the U.S. Environmental Protection Agency has approved the proposed changes to the state's water-quality standards.

Two of the bigger changes include adding nutrient standards for lakes and standards for the herbicides metolachlor and acetochlor. The standard for acetochlor is the nation's first.

The approval means that the standards will now be used for Clean Water Act programs, such as when the state agency issues wastewater treatment facility permits and conducts water quality assessments.

The federal Clean Water Act requires states to update their water quality standards every three years. The nutrient standards for lakes are to address eutrophication, an increase in nutrients and algae. Phosphorus, the main cause of eutrophication, is almost always responsible for lakes becoming green due to excessive algae. The changes to standards include numeric standards for phosphorus and two indicators of eutrophication that measure the response of lakes to excess phosphorus. Specific numeric lake standards vary by the ecological regions in the state and include four different types of lakes.

Courtney Kowalczak, director of Minnesota Waters' citizen monitoring program, said her organization is excited to see numeric nutrient standards being set for our lakes. "The addition of these standards will be another tool for our citizen volunteers to use to safeguard our state's lakes," Kowalczak said. "While it is encouraging to see steps being taken to restore our polluted waters, we must not forget our responsibility to prevent damage to our currently healthy lakes."

At the request of the Minnesota Department of Agriculture, the Minnesota Pollution Control Agency developed water-quality standards for acetochlor and metolachlor. Both of these herbicides are used to control annual grasses and some broadleaf weeds. More than 3 million pounds of acetochlor and 1 million pounds of metolachlor were sold in Minnesota in 2005 for use mainly on corn. The acetochlor and metolachlor standards are protective of human health, aquatic animals, and aquatic plants.

Other changes to the water-quality standards include: • New or expanding wastewater treatment facilities must meet a 1-milligram-per-liter total phosphorus effluent limit after May 1, 2008, if they discharge more than 1,800 pounds of phosphorus per year. • A fish tissue standard for mercury has been added. • Fecal coliform bacteria standards have been replaced by E. coli standards.

For additional information on the standards, visit www.pca.state.mn.us/water/standards/rulechange.html.

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