Minnesota's polluted drinking water is getting a lot worse

According to a recent report, Rock County saw a “staggering” 890 percent increase of nitrates in the drinking water over the past few decades.

According to a recent report, Rock County saw a “staggering” 890 percent increase of nitrates in the drinking water over the past few decades. Brian Peterson, Star Tribune

For a long time, Minnesota—especially its rural communities to the south—has had a problem with nitrates.

They’re chemicals commonly found in fertilizers and manure, and they’re not inherently a bad thing. If we hadn’t harnessed nitrogen for agriculture around World War II, there’s no way we could have fed the number of human beings alive today with the limited amount of land we have.

But when we put nitrates in the ground, they often wend their way into our bodies via our drinking water. That leads to a number of unpleasant, sometimes fatal health problems, especially in babies and pregnant women.

With that in mind, Environmental Working Group, a nonprofit environmental research organization, has been tracking nitrate levels in Minnesota’s water between 1995 and 2018.

The initial results weren’t exactly surprising. Some 115 Minnesota community water systems—mostly in the southeast, southwest, and central regions of the state—had “elevated” nitrate levels. That means at or above three milligrams per liter, not yet at the five milligrams per liter associated with risk of birth defects and other health problems, but high enough to start paying attention.

More than a third of those communities’ nitrate levels actually went down over the course of the study. What was disconcerting was the number of communities whose nitrate levels rose during that time.

“For the 72 communities we analyzed where contamination rose, average nitrate contamination of drinking water jumped by 61 percent between 1995 and 2018,” EWG's report says. “It is clear that in most places with the most serious contamination, the problem is getting worse.”

Take the southwest Minnesota town of Adrian, where some 1,200 residents get their water from wells. Nitrate contamination has increased by 96 percent over the course of the study. In fact, in 2015, nitrate levels got so bad that town officials shut down the water treatment plant and issued vouchers for free bottled water.

At the time, deputy clerk-treasurer Rita Boltjes told the Star Tribune it was “just part of living in Adrian.”

Then there was Rock County, down in the southwest corner of the state, which saw a “staggering” 890 percent increase. That’s not great news for the nearly 2,300 people who drink the water there.

In most places included in EWG's study, buying bottled water instead of installing a filtration system would be a big expense. Of those 72 communities included, 61 percent had a below-average median household income, according to Census Bureau data.

State officials know about this problem, and they’ve been trying to correct it with the Minnesota Groundwater Protection Rule, which went into effect at the beginning of this year. It bans laying down nitrogen fertilizer in vulnerable areas when the soil is frozen, and therefore more likely to let the chemicals slide right off and into nearby groundwater. It’s supposed to keep nitrate levels from exceeding 10 milligrams per liter, which is the Environmental Protection Agency’s legal limit.

Even getting that much passed took decades of work and overcoming a last-minute derailing maneuver by a cadre of mostly Republican legislators. (More on that here.) But the EWG worries it will still be “too little, too late.”

“To improve the way farmers and landowners use and manage fertilizer and manure, the rule relies heavily on their voluntary participation,” a report published in January explained. “Provisions in the rule could delay enforcement of mandatory measures for years.”