Nitrate cited as a 'growing threat' to Minnesota's drinking water

Farm-related nitrate pollution represents a "growing chemical threat to Minnesota's drinking water," according to a new Health Department report that could spark action on clean-water legislation in the final days of the 2015 Legislature.

Community water supplies, overall, are safe and closely monitored, according to the agency's Drinking Water Annual Report for 2014. But the report, released Wednesday, highlights widespread and often costly efforts to prevent or reverse nitrate pollution in well water drawn by municipal and quasi-public water systems — those used by schools, businesses, resorts, restaurants and other places.

"I think this underscores again that we have a widespread problem with water quality in Minnesota," Gov. Mark Dayton said Wednesday at a news conference with Health Commissioner Dr. Ed Ehlinger and other high-ranking health department officials in St. Paul.

The unusual formality surrounding the report's release signaled the importance the Dayton administration has placed on cleaning up Minnesota's lakes, rivers, streams and aquifers. Dayton said the state urgently needs antipollution legislation this year because "bad water threatens our health, our economy, and our future."

Nitrate, a compound of nitrogen and oxygen, comes from many sources, including manure, septic systems and natural decomposition of organic matter. But the report said fertilizers applied to land used for row-crop production "are the biggest influence on Minnesota's ground and surface water nitrate levels."

Waters affected by nitrogen fertilizer may also contain pesticides, the report said.

Research shows the clearest risk from elevated nitrates is for infants from birth to 6 months who drink water or formula made with water. They can develop a condition known as Blue Baby Syndrome, which reduces oxygen supply in their blood. A University of Minnesota physician discovered the relationship in the mid-1940s and the state Health Department documented 146 cases and 14 deaths, mostly in southern Minnesota, between 1947 and 1949.

The effects on pregnant women and nursing mothers are "less clear," said Tannie Eshenaur, planning director for drinking water protection at the Health Department. But the department advises them not to drink water with elevated levels of nitrate.

In addition, the National Cancer Institute has suggested a link between elevated nitrate levels in drinking water and an increased risk of non-Hodgkin lymphoma.

In Minnesota, about 75 percent of people get their drinking water from wells. The state is responsible for safeguarding the quality of drinking water from 6,000 quasi-public or "non-community" water suppliers and 960 community suppliers, mostly towns and cities.

While no municipal water systems violated the federal health limit for nitrates in 2014, about 105 "non-community" systems were found with nitrate concentrations at or above the maximum contaminant level, the report said. And earlier this year, the central Minnesota town of Randall violated the health limit and was forced to shut down one of its two wells and warn every resident of the health danger.

According to the Health Department, eight communities that previously violated the limit for nitrates are now running expensive nitrate-removal systems at a cost per household of up to $3,500. Elsewhere, the agency is working with 45 communities around the state that need to slow or reverse nitrate pollution in their public water systems.

"These actions can include drilling a new well, installing a treatment system or connecting to another public water system," the report said.

Dayton's biggest initiative for cleaner water is a bill that would require farmers to plant 50-foot-wide strips of natural vegetation between their fields and waterways. Those barriers would help prevent up to a third of nitrate contamination in surface waters. The governor said he met this week with farm groups to discuss the bill, and the Minnesota Pollution Control Agency on Wednesday released new data showing how buffers are critical to protecting aquatic life in streams and rivers.

The state's main farm organizations have opposed the buffer-strip bill, arguing that their members already are taking steps to reduce chemical runoff.

The Health Department also conducted more than 22,000 tests for pesticides and industrial contaminants in water systems last year, the report said. It provided no breakdown of the findings, but it said no systems have violated drinking water standards for those pollutants.

Karla Peterson, supervisor of the department's Community Public Water Supply Unit, said the herbicide dalapon was the most common "synthetic organic compound" found in the tests. Atrazine, a common pesticide used in agriculture, was the next most common finding, she said.

The highest concentrations detected for the two chemicals were far below the U.S. EPA's level of concern. In nine years of testing there have been 31 detections of dalapon and 11 of atrazine, Peterson said. She said the state increases monitoring of wells that contain elevated levels of nitrate because those wells are proven to be vulnerable to other farm chemicals and their degradates.

Tony Kennedy • 612-673-4213