Tests show nitrate increase for almost two-thirds of Minnesota farm country’s drinking water

(FOX 9) - An analysis of drinking water in Minnesota’s farm country has found about 63 percent of systems saw increases in nitrate.

According to the Environmental Working Group (EWG) analysis, 72 systems tested out of 115 showed increases between 1995 and 2018. EWG says 218,000 people are impacted by the increases in nitrate.

67 percent of those systems had nitrate at or above the federal legal limit of 10 milligrams of nitrate per liter. That limit was instituted with the U.S. Safe Drinking Water Act.

Nitrate does occur naturally in soil at low levels, but contamination higher than 3 milligrams per liter indicates a human cause, the EWG says. Research shows 5 milligrams per liter of nitrate is associated with higher risk of cancer and birth defects.

Nitrate generally comes from fertilizer and manure that runs off farm fields and into water supplies. In January, Minnesota enacted its Groundwater Protection Rule, but enforcement of the rule has lagged, according to EWG.

“Rapid, strong action is needed to protect Minnesota’s tap water from agricultural pollution,” said Anne Weir Schechinger, EWG senior economic analyst and the report’s author. “The problem is not only widespread, it’s also getting worse at an alarming rate.”

“For nearly 30 years, Minnesota has relied on a voluntary approach to working with farmers to protect drinking water, but surveys show fertilizers are still over applied to crop fields,” said Jamie Konopacky, EWG’s Midwest director. “But the state’s new Groundwater Protection Rule includes no immediate and practical requirements for farming operations to ensure communities have safe drinking water.”