Research shows tainted Wisconsin water tied to animal waste
By Sarah Whites-Koditscheck, Wisconsin Public Radio and Coburn Dukehard, Wisconsin Center for Investigative Journalism
via WTMJ-TV Milwaukee - Mar 10, 2019
KEWAUNEE, Wis. (AP) — Scientists are one step closer to understanding how dangerous contaminants from fecal matter are entering private wells in a northeastern Wisconsin county. New research by U.S. Department of Agriculture microbiologist Mark Borchardt shows nitrate and coliform in the water mostly comes from agriculture — and not human waste.
"Where we see the strong relationships, the strong linkages, those are with agricultural factors. So that would suggest that agriculture is primarily responsible for those two contaminants," he said in an interview.
Kewaunee County, where cattle outnumber people nearly 5 to 1, is a focal point in Wisconsin over whether local, state and federal governments adequately protect drinking water from manure from dairy farms, especially in areas of fractured bedrock, which is common in northeastern Wisconsin. The fractured bedrock allows for water to easily infiltrate to the subsurface, especially after rain or snowmelt.
Borchardt presented his updated findings on the risk factors associated with contamination in wells at the Midwest Manure Summit in Green Bay on Feb. 27. In 2017, his research found over 60 percent of wells sampled in Kewaunee County were contaminated with fecal microbes, which can come from both septic systems or animal waste.
The new study aims to understand the precise sources of contamination and how certain factors can reduce or increase the risk of tainted drinking water. Borchardt used models to predict how those factors — like the distance of a well from a manure lagoon or agricultural field, weather and the quality of well construction — can impact contamination levels.
Borchardt's study found that the No. 1 risk factor for contamination was the proximity of a well to a manure storage pit. Borchardt said the closest well in the study was 150 feet from a manure pit, but even wells three miles away still have some risk of being contaminated with coliform.
Borchardt called coliform an "indicator bacteria" for the presence of other bacteria and pathogens.
According to state regulations, manure lagoons are allowed to leak 500 gallons per acre, per day. Borchardt said contamination of nearby wells may be due to leakage from the lagoon, as well as the tendency of farmers to spread liquid manure close to the location of their pits.
According to a spreadsheet of permitted manure storage pits...