Cow manure predicted to cause most sickness from contaminated wells in Kewaunee County
The No. 1 factor for acute gastrointestinal illness in Kewaunee County’s private drinking water wells is cow manure, according to a federal study released Wednesday. The findings raise questions about the effectiveness of existing regulations aimed at protecting residents from tainted drinking water.
The study predicts that cow manure causes 230 cases of acute gastrointestinal illnesses in the county per year, out of 301 total cases of sickness — with an additional 12 cases caused by human waste from septic systems. The contaminant is unknown for the other instances, the authors wrote.
Symptoms of gastrointestinal illness can include nausea and vomiting, diarrhea and abdominal cramps, sometimes accompanied by fever. Children, the elderly and people with underlying health conditions can be more vulnerable to complications such as dehydration.
Kewaunee County, where cattle outnumber people nearly 5-to-1, has been at the forefront of discussions in Wisconsin over whether local, state and federal governments adequately protect private well water from contamination from dairy manure, especially in areas of fractured bedrock, which allow contaminants in the soil to move quickly into the groundwater and is common in northeastern Wisconsin.
The main source of illness in private wells was found to be the parasite Cryptosporidium, which was estimated to cause 250 cases of illness per year.
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The research also reached a surprising finding: More than 80% of cases were predicted to come from wells located where the depth to bedrock is greater than 20 feet — where most people’s wells are located.
The study, by lead author Tucker Burch, a U.S. Department of Agriculture research agricultural engineer, was published Wednesday in the journal Environmental Health Perspectives. Also published Wednesday was a companion study by USDA microbiologist Mark Borchardt that found nitrate and coliform in Kewaunee’s drinking wells mostly comes from agriculture — not human waste from septic systems.
Borchardt’s study examined the sources of well water contamination and which factors can reduce or increase the risk of tainted drinking water. His team used models to predict how those factors — like the distance of a well from a manure lagoon or agricultural field, number of septic systems, weather and the quality of well construction — can impact the levels of contamination.
That study found that the main risk factor for well contamination by coliform bacteria was its proximity to a manure storage pit, a common method used by large farms to store and later dispose of manure. Also, it found that digging a deeper well didn't protect that well from getting contaminated, meaning that even if a homeowner gets a new well drilled, that may not protect the household from contamination.
Burch’s study was based on a yearlong, countywide pathogen occurrence study conducted from April 2016 to March 2017 that examined 138 private well samples. Borchardt’s study was based on those samples, as well as hundreds of others tested for coliform and nitrate analysis. According to Borchardt, the two papers represent the most comprehensive, site-specific private well study in the U.S.
A leading farmer in the area questioned the value of the findings of Burch’s study, saying manure practices have improved significantly since those water samples were taken.
Don Niles, a Kewaunee County dairy farmer and president of the nonprofit Peninsula Pride Farms says farmers in Door and Kewaunee counties are using improved techniques to manage manure, including planting more cover crops to improve soil health. And, he says about half of all manure spread on shallow soils in Kewaunee County goes through a digester first.
“We have to demonstrate that we’ve destroyed 999 organisms out of 1,000 (before landspreading the manure)," Niles said, "So a 3,000-cow dairy that digests manure now is spreading the same amount of coliforms as a three-cow dairy with no digester. So that’s substantial. That’s not just taking a little off the edge.”
Regulations fall short?
Burch’s report could have important implications for land use and water resource management in Kewaunee County — and elsewhere across the state with a fractured bedrock geography — as it predicts for the first time the number of acute gastrointestinal illnesses and the specific fecal source.
Private wells in Wisconsin aren't monitored by government agencies, and the maintenance and testing of well water is in the hands of the well owner. Borchardt’s research shows that a new or deeper well doesn't necessarily provide protection.
Recent changes to the state’s manure management rules prohibit all dairy farms in areas of the state with Silurian bedrock from mechanically applying manure on fields with less than 2 feet of soil over bedrock or groundwater. They apply to some areas in Brown, Calumet, Dodge, Door, Fond du Lac, Kenosha, Kewaunee, Manitowoc, Milwaukee, Outagamie, Ozaukee, Sheboygan, Racine, Walworth, Washington and Waukesha counties, and will be implemented over the next 10 years.
The regulations place the most restrictions on solid and liquid manure spreading in areas between 2 and 5 feet to the bedrock. There are fewer restrictions on areas with soil depth between 5 and 20 feet. But, Burch noted that shallow wells are uncommon in Kewaunee County, and most wells there are more than 20 feet deep.
Joe Baeten, the northeast watershed management regional supervisor for the state Department of Natural Resources, says the findings from Borchardt’s research team helped inform the rulemaking process.
“Now that the rules are in place, we want to know, will the rules work?” Baeten said. “Down the road, there might be another phase where we ask, ‘Did the rules work after we got past 10 years of implementation? Have we seen results?’ It’s a long, phased process.”
Lagoons, landspreading eyed as sources
Borchardt’s and Burch’s research also suggests that current farming practices are contributing to well contamination and illness, because of the way manure leaks from storage lagoons and manure spread on land seeps through the bedrock into the aquifer and private wells.
Niles, however, challenged the design of Burch’s new study, saying it overstates the level of disease in the area. He noted that the study is predictive, not epidemiological, and doesn't reflect the number of cases reported to local health officials.
But the researchers note that their findings are consistent with actual cases reported to the Kewaunee County Public Health Department.
That department reports an average of 4.5 cryptosporidiosis cases per year between 2015 and 2020, and 4.2 cases of salmonellosis. But Burch says those numbers are artificially low, as such ailments tend to be underdiagnosed and underreported. He says scientific literature suggests that, for every one case of cryptosporidiosis reported, there are 100 more that go unreported. For salmonellosis, the comparison is 1 to 30.
“Not everyone who gets one of these diseases goes to see a doctor," Burch said. "Not everyone that sees a doctor gets tested. The tests involved don’t always work perfectly. And the test results don’t always get reported to public health agencies.”
All of the 17 concentrated animal feeding operations (CAFOs) in Kewaunee County have nutrient management plans designed to regulate when, where and how much manure can be spread on agricultural fields to meet crop nutrient needs while also reducing the potential for runoff into ground and surface waters.
According to the state Department of Agriculture, Trade and Consumer Protection, in 2020, about 36% of Wisconsin’s croplands had such a plan and about 70% of farms were in compliance with the terms.
But the conservation group Wisconsin’s Green Fire published a 2019 report on nitrates in drinking water, arguing “compliance with existing nutrient management guidelines is by itself insufficient to protect water quality.”
In fact, Borchardt says that the more fields with nutrient management plans surrounding a well, the greater the chance that the well will be contaminated with high nitrate.
“This suggests nutrient management plans in Kewaunee County are not mitigating nitrate contamination of groundwater,” he said.
Tainted well, yard full of manure
One family that has experienced the effects of high nitrates and bacteria in its well water is Arlin and Mary Lou Karnopp, who live near Luxemburg — about 20 miles east of Green Bay in Kewaunee County.
Their household was part of the original well water study conducted by Borchardt and others, with one test showing elevated levels of coliform bacteria, another showing elevated levels of nitrate-nitrogen. In 2016, the Karnopps stopped drinking or cooking with their well water, although they do use it to shower.
The Karnopp family has suffered many health problems over the years. Their son-in-law, who lives in nearby Casco, had stage 3 colon cancer, which can be caused by high nitrates in water. Their grandson was born without a hip. Mary Lou has suffered multiple bladder infections tied to E. coli, and in 2020, she had a stroke. The Karnopps can’t prove the health issues are due to tainted water, but say they continue to wonder whether that was the cause.
In addition to a contaminated well, the Karnopps suffered an additional manure-related catastrophe in February 2019 when frozen manure spread on a neighbor’s property thawed, flowed downhill and flooded their yard with liquid manure, later freezing and then thawing again into a pool of manure-contaminated water 50 feet around and several inches deep.
Karnopp took water samples, which showed results that were “indicative of manure,” according to James Iverson from the private lab Analytichem. The DNR took samples that tested positive for E. coli.
The state DNR notified Halls Calf Ranch, which spread the manure on the property, that it was violating its state wastewater permit, and the farm was ordered to have “no further unauthorized discharges to waters of the state as a result of manure runoff.”
To date, the Karnopps have received no compensation for the mishap from the government or the neighboring CAFO where the manure was spread. The Karnopps are weighing whether to dig a new well — or even sell the home on land once owned by Arlin’s great-grandfather.
He remains skeptical the family will have a positive resolution. In a recent email, he wrote, “We might as well talk to a brick outhouse.”
This piece was produced for the NEW News Lab, a local news collaboration in Northeast Wisconsin
This article originally appeared on Green Bay Press-Gazette: Cow manure predicted to cause most sickness from contaminated wells in Kewaunee County