Clean water groups applaud MPCA study
Minnesota’s clean water advocates praised the Minnesota Pollution Control Agency this week for its comprehensive study documenting the sources of nitrogen pollution that endanger Minnesota’s drinking water, fish and aquatic habitat – and contribute to the Dead Zone in the Gulf of Mexico.
Working with the University of Minnesota and the U.S. Geological Society, MPCA tested more than 50,000 water samples as part of its extensive study of the causes of nitrogen pollution. In addition, the agency reviewed more than 35 years of monitoring data and findings from 300 published scientific studies.
Key findings included:
- Drinking Water — Maximum levels of nitrates in Minnesota’s rivers and streams exceeded the state’s safe drinking water standards in 27 percent of monitored sites.
- Fish & Habitat: Elevated nitrate levels can be harmful to fish and aquatic life threatening fish and habitat in rivers, lakes and streams.
- Dead Zone: Minnesota is the sixth highest contributor of nitrogen to the Gulf of Mexico. Minnesota and other states must reduce nitrogen loading to reduce the devastating impacts of oxygen depleted waters in the Gulf, which adversely impacts commercial and recreation fishing as well as the overall health of the Gulf ecosystem.
- Ag Cropland: 73 percent of the elevated nitrate levels come from cropland, primarily through agricultural drainage systems below cropped fields and by nitrate pollution leaching into groundwater, and then moving underground until it reaches streams.
“The level of change needed is sweeping,” said Kris Sigford, water quality program director for Minnesota Center for Environmental Advocacy.
The study notes that up to a 13 percent reduction in nitrate pollution can occur if changes to fertilizer use are broadly adopted, but that additional and more costly practices also will be needed to make further reductions in order to restore our water quality and treat our downstream neighbors fairly.
MPCA points to two solutions that would make significant reductions in nitrogen pollution: 1) changes in the use of drainage systems under cropland – so that nitrogen collected from fields is slowed, filtered or diverted rather than heading directly into rivers and streams and groundwater; and 2) increased use of complementary cover crops in our corn and soybean fields and shifting some cropland away from such row crops to perennial crops that provide continual ground cover.
“The MPCA is on the right track in its recommendations to reduce nitrogen pollution,” said Whitney Clark, executive director of Friends of the Mississippi River. “It is time to take real steps to protect our rivers and streams from the pollution delivered by tile drainage systems under cropland. These drainage systems deliver 37 percent of total statewide nitrogen water pollution.”
“This is a game-changing study,” said Steve Morse, executive director of the Minnesota Environmental Partnership. “These scientific findings cannot be denied.”