As crops spread, some land can no longer cleanse nitrates from groundwater.
Debbie Carlson filled up a bottle of water on one of her properties near Red Wing, Minn., on Thursday, December 6, 2012, to bring back to her Hastings home for drinking and cooking. Carlson has high nitrate levels in her well water so every other day she drives for 20 minutes to collect her drinking water.
HASTINGS - Debbie Carlson can laugh at the irony: She's the wife of a well digger who can't find good water for his own family.
Like one out of three wells in Dakota County, hers is so contaminated with nitrates she won't let anyone drink from it -- especially her 8-year-old granddaughter. Most likely it comes from nitrogen used as fertilizer on the cornfields surrounding her home. "Nitrogen was a great thing for the family farm," Carlson said. "But I am paying the price."
Thanks to a combination of geology and some of the country's richest farmland, thousands of Minnesotans face elevated levels of nitrates in their drinking water. It's a health risk -- mostly for infants and pregnant women -- and a significant economic burden. Hastings is one of nearly a dozen Minnesota communities that has spent millions to clean the toxin from drinking water. Well owners like the Carlsons have three choices: Drink it, which some do. Pay thousands for a new well. Or install expensive treatment systems.
The prairie that once protected groundwater is long gone from Dakota County and from most of Minnesota and the Midwest. That loss lays bare what one leading agricultural economist calls the "wicked problem" of global nitrogen pollution.
By converting grasslands and pastures to fertilizer-intensive crops, modern agriculture has produced an extraordinary bounty of corn, sugar beets and potatoes for a growing global population. But it also has eliminated the valuable "ecological services'' that native landscapes provide -- such as filtering groundwater -- at great cost.
Now, through an emerging statewide strategy, the Minnesota Department of Agriculture is devising a range of fixes, including more water monitoring and guidance on how communities can restore some of the lost prairie landscape.
In the process, officials and farmers will tackle two thorny questions: How will government use its power to regulate nitrogen use in contaminated areas? And even if every landowner follows the best guidance science can provide, when will they know if it works?
Striking the right balance is crucial because the current approach, said Jill Trescott, Dakota County's groundwater-protection supervisor, imposes a cost shift from agriculture to taxpayers and homeowners that is "just not fair."
Says Carlson: "I think water is one of our most precious resources. What are our grandchildren going to be left with?"
Corn and geology
In Minnesota, three-fourths of people get their drinking water from groundwater. On average, 6 percent of private wells are contaminated with nitrates. About a dozen community water systems have "pretty severe nitrate problems," said Bruce Montgomery, manager of the Agriculture Department's fertilizer and pesticide division. Health officials say that once or twice a year another community hits the limit.
The problem is concentrated in several regions: Dakota and Washington counties; the 14 counties that make up the Central Sands region in the middle of Minnesota; the southeastern "karst'' region, where the cracked limestone geology sends water straight down to the aquifers, and southwestern Minnesota, where a shortage of water in general aggravates the nitrate problem.
In Dakota County, the first place in Minnesota to trace nitrates directly to agriculture, the problem is partly an accident of geology. West of Hwy. 52 a thick layer of till -- clay, gravel and sediment left behind by the last glacier -- lies beneath the rich soil, so that water percolates slowly down from the surface.
But on the county's eastern side, the melting glaciers left behind sand on top of bedrock, and water rushes through it like a sieve -- down to the aquifers or into the Vermillion River and eventually the Mississippi River, said Tim Cowdery, a U.S. Geological Service hydrogeologist who has studied it. Carlson's husband, she said, describes it as "young water."
Geology wasn't as much of a problem back in the day when farmers planted more varieties of crops, many of which required less nitrogen. But in Dakota County, like much of Minnesota, corn and soybeans are now the primary crop. Soybeans pull nitrogen out of the air and fix it in soil, where it can leach into the water. And corn, more than most any other crop, demands fertilizer to produce the yields that have climbed steadily for decades.
Since the late 1980s, corn yields per acre have nearly doubled. The number of acres devoted to corn in Minnesota has grown by a third. In short, nitrogen is money for corn farmers, said Greg Buzicky, head of the nitrogen-management plan for the state Agriculture Department. "It drives their profit and their income," he said.
Farmers actually have cut their nitrogen use drastically -- the volume of corn produced has climbed seven times faster than fertilizer use.
Ed Terry, a farmer and livestock operator near Northfield, recalls a time when dealers would hang plaques on their wall boasting about how many tons of fertilizer they sold. But now "we are getting better at buying just the right amount.'' Farmers use computers and GPS technology to apply fertilizer to protect the water, the land and their bottom line, he said. He even tests nitrogen levels in his cattle's manure before applying it to his fields, he said.
Still, in Midwestern states where corn can stretch across the horizon, the rate of nitrogen taken up by the crop "is not terribly good," said Otto Doering, a Purdue University professor who headed a federal scientific advisory panel on nitrogen pollution. Corn uses just 30 to 50 percent of the fertilizer that farmers apply, he said. Some of the consequences are enormous, like the Gulf of Mexico "dead zone," an area so contaminated with nutrients that it cannot sustain life. Some, like the Carlsons' well, are small and much closer to home.
Blue baby syndrome
Debbie Carlson started buying water from Culligan in 1994, when tests showed nitrate concentrations in the family's water were well above the health standard set by the federal government. She had four kids at home.
The health standard was set decades ago to protect pregnant women and infants from the malady commonly called "blue baby syndrome." In the 1950s, researchers showed that high nitrate levels suppress oxygen in the blood of babies, a potentially fatal condition that turns them blue. Other studies have raised questions about nitrates' connection to cancer and thyroid and reproductive problems in both humans and livestock.
Federal regulators say there is not enough evidence to warrant a tougher standard. But Carlson clearly remembers a client from years ago -- a sheep farmer whose well had nitrates three times the health standard and whose ewes couldn't reproduce. After the Carlsons drilled a deeper well with low nitrates, "everything was fine," she said.
"I'd hate to get an illness and trace it back to the water I drank," she said.
For years, she spent $40 to $60 per month with Culligan or hauled water from her sister's house in Hastings.
But then Hastings had nitrate problems of its own.
Just up the road from the Carlson's home, Tom Montgomery, Hastings' public works director, manages one of the state's most sophisticated water-treatment systems. For years, he watched nitrate levels in the city water rise gradually, until the City Council finally voted to build a $3 million treatment plant, completed in 2006, to remove nitrates from two of its wells.
For now, the water is fine, Montgomery said. But nitrate levels in two other wells are halfway to 10 parts per million, and there are two more "we are keeping our eye on," he said. If they get close to 10, then the city might face another expensive decision.
Worse, he said, it might no longer be possible to drill wells that meet water-quality standards without millions more in treatment costs. That, he said, would put a lid on the city's growth. "It will come down to who pays," he said. Hastings Mayor Paul Hicks says the decision to build the plant was not controversial among residents and business owners. "We know where we live," he said. "The agricultural community is important to Hastings."
Well owners with nitrate contamination pay three to six times as much for drinkable water, according to state authorities. And some people are not willing to pay it.
"I drink the water," said Ryan Wahlstrom, 39, whose well water at his home outside Hastings has nitrate concentrations above the health limit. He's single, with no kids, and rather than put in a water-treatment system, he decided to "throw caution to the wind."
But Carlson is not willing to take that risk. Her husband drilled a second, deeper well, but the water was undrinkable -- it had too much iron and turned their bathtub orange. They considered a filtration system, but they would have had to put in a new septic system as well, she said. So today, they use the water from the contaminated well for everything but cooking and drinking. Every other day or so, Carlson loads two 10-gallon plastic jugs into her truck and drives 15 miles south to property she and her husband own near Welch that has a well with good water. Carefully, so the jugs don't tip over in her truck, she hauls them home and sets them up in her kitchen.
"It's a pain," she said. "I don't know what I'm going to do."
Minnesota came up with its first plan to manage fertilizer use nearly a quarter-century ago. The state's best agricultural scientists devised plans for each region of the state, advising farmers how much to apply and when. For the most part, surveys show that farmers follow the guidelines, said Montgomery. In some parts of the state, nitrate contamination might be leveling off, and in some places it seems to be getting worse, he said.
Two years ago, the Department of Agriculture, which is responsible for protecting the state's groundwater, launched a new initiative. This time, the agency is considering more intensive monitoring of groundwater; as nitrate levels rise, so would community awareness and the rules governing nitrogen use. At the highest levels of contamination, nitrogen use would be restricted, farmer education would be required and so would soil testing.
In a word, regulation.
But in places like eastern Dakota County, where it might make sense to grow something other than corn or bring back some of the prairie to protect the water, communities are on their own. There are no laws that they can use, Buzicky said. The hope is that local governments, farmers and landowners will figure out how to work together, as they are doing in some places, he said.
It will be a generation or two before anyone knows if that works -- one reason why Doering calls nitrogen pollution a wicked problem. Solving it, he said, is harder than sending a man to the moon.
Debbie Carlson has a more terrestrial view. "Whatever you put on the earth has to go somewhere," she said.
Josephine Marcotty • 612-673-7394
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