More farming across southeast MN will lead to huge increase in polluted water, study says


Most of the time, a boom in crop prices is a good thing for a rural area. That's what it's felt like in southeast Minnesota for most of the past decade or so, as increasing prices for grains like soybeans and corn led to record incomes for the state's farmers as recently as a few years ago.

But according to a study released last week from the University of Minnesota, it appears that the recent emphasis on growing those money-making grains may have had a severe unintended consequence -- nitrate chemicals contaminating nearby drinking water sources.

See also: Minnesota has country's best corn crop in a drought-stricken season, USDA says

The study, which focused on 11 counties in southeastern Minnesota, found that converting so much of those grasslands into croplands has led to a huge increase in the number of nitrogen-rich fertilizers being used by farmers. And that, in turn, could lead to a 45 percent increase in the number of nitrogen-contaminated private wells in the area over the next 20 years.

Nitrogen is necessary for farming. It makes plants grow faster, greener, and healthier. But when there's too much nitrogen in the soil, it can contaminate the water nearby, leading to nitrate levels well past the EPA's 10-parts-per-million limit. That can lead lead to health problems, from reduced oxygen flow to brain damage, especially in infants.

"There are the obvious health effects," said Keeler. "But what we were most interested in were the economic costs," Keeler says.

Those costs won't be anywhere close to cheap for homeowners. The study didn't look into what the nitrogen pollution could mean for public water sources, only private wells. But it turns out that when you add up the cost to fix all of those wells, the price can be staggering.

"So homeowners could choose to do nothing, which is what a lot of people tend to do, and there may be consequences associated with that," Keeler says. "But if you do decide to do something, you could dig a well, which could cost something like $16,000, not to mention maintenance costs. Or you could add a treatment system, which is $600 or $800. Or you can buy bottled water. And that's all money."

(Read on to page 2 to found out how it got so bad.)


In total, the study estimates that the costs for the 11 southeastern counties could range anywhere from $1.5 million up to nearly $5 million.

So how did the problem get so bad? We contacted Paul West, the co-director of UMN's Global Landscapes Initiative, to find out. He says that as far as nitrates go, there's good news and bad news. The good news is that fertilizer companies have been able to make their products more efficient, so they don't need as much nitrogen as they used to. But the bad news is that due to the boom in crop prices, Minnesota farmers are using way more fertilizer, so the amount of nitrates entering the soil isn't going down at all.

"It's the equivalent of cars becoming more efficient, but if there are twice as many on the road and driving a lot more miles, you're still getting that same amount of pollution," West says.

On the state level, the last time Minnesota updated its plan for nitrogen fertilizer was all the way back in 1990. But that's finally started to change in the past few years. The state started the process of revising the plan in 2010 and released an updated plan for study last year. The new draft plan isn't final, but it does take some steps to help, including increased testing and suggesting ideas for "alternative" practices that promote less nitrogen pollution.

But there are still a lot of questions to consider. The new plan may not pass, and even if it does, some remain unconvinced that the plan does nearly enough to curb the growing problem. So the issue of nitrogen pollution isn't about to go away.

Send your story tips to the author, Robbie Feinberg. Follow him on Twitter @robbiefeinberg.