DNA evidence traces drinking water hazards back to farms and manure
A sophisticated new analysis of conditions around hundreds of polluted wells in Wisconsin found that farming and animal manure pose far greater risks than other factors linked to two contaminants that have consistently posed serious health hazards in places with vulnerable drinking water sources.
The conclusions of the research led by U.S. Department of Agriculture microbiologist Mark Borchardt are bound to stir controversy because they raise questions about the adequacy of state regulations that are supposed to protect water from the hundreds of millions of gallons of dairy manure stored in lagoons and spread on the ground.
Tony Evers’ proposal to expand a state program that helps homeowners rebuild polluted wells.
In an interview with the Wisconsin State Journal before the conference, Borchardt said the study of Kewaunee County wells is applicable to all parts of eastern Wisconsin and other places in the Midwest with a porous bedrock formation called Silurian dolomite.
Borchardt’s research team analyzed conditions around each of hundreds of wells, including distance from farm fields, manure storage sites and septic fields, along with data on well construction, and the depth to bedrock and groundwater.
He said he was surprised to see that the highest risk for coliform bacteria was not how near a well was to farm land, but specifically the well’s proximity to a manure storage site.
The new study found the strongest statistical links by far were those linking coliform-polluted water with nearby manure storage.
Agricultural interests have opposed monitoring.
A few years ago, citizens demanded that a monitoring requirement be included in the permit of a large dairy feedlot, but the state resisted and eventually the case went to court.
The findings come on the heels of another study Borchardt was involved in that found 42 percent of wells in three southwest Wisconsin counties were contaminated.