SOUTHWEST WISCONSIN - Widespread reporting on the extent of well water contamination in southwestern Wisconsin that appeared in the past week appears to be substantially incorrect.
The initial source of that reporting seems to be a story by reporter Lee Bergquist that was published in the Milwaukee Journal Sentinel’s JS Online at 12:38 p.m. on Thursday, August 1 and updated at 2:54 p.m. on Thursday, August 1.
“As worries grow over contamination of rural drinking water, a new study of private wells in southwestern Wisconsin found the overwhelming majority were contaminated with fecal matter,” Bergquist wrote. “Results from the independent study released on Thursday showed that 32 of 35 wells — or 91 percent — contained fecal matter from humans or livestock.”
However, Bergquist fails to report that the 35 wells referenced were selected from a sample of wells previously identified in an earlier round of the study’s testing as contaminated. This fact is made abundantly clear in study’s official press release titled ‘SWIGG Study Update-Identifying Sources of Fecal Contamination in Private Wells…’
“The Southwest Wisconsin Groundwater and Geology Study of Grant, Iowa, and Lafayette Counties has entered its second phase: identifying fecal sources of contamination in homeowners’ private wells,” the official press release states in the lead paragraph. “Samples were collected in mid-April 2019 from 35 private wells. Wells were randomly selected from those previously found during the study to be contaminated with coliform bacteria or high nitrate (above the drinking water standard of 10 ppm).”
It isn’t until halfway through the Journal Sentinel story that Bergquist even references the previous testing–through which the 35 wells tested in this story were actually identified as contaminated.
“In that first round (of well testing), 42 percent of 301 wells had evidence of total coliform or nitrate that exceeded the state's health standard,” Bergquist wrote. “In a second round of 539 wells, 27 percent turned up total coliform or nitrate above the state standard.”
Combining the results of both rounds of initial testing it appears approximately 272 of the 840 wells tested were identified as contaminated. That’s about 32.4 percent–meaning a little less than one third of the wells tested were identified as contaminated. It also means that more two thirds of the wells tested in the initial rounds of the study did not show substantial contamination.
So with the stage set by Bergquist’s omission of the fact that the 35 wells were a random sample from wells previously found to be contaminated, Associated Press picks up the story from JS-Online.
AP credits information in the story to the Milwaukee Journal and JS Online. However, they offer a rewrite of Bergquist’s story in their copyrighted version of it.
“The majority of private wells in southwestern Wisconsin are substantially polluted with fecal matter as concerns intensify over pollution of rural drinking water, according to a new study,” AP writes.
“Results from the independent study released August 1 indicated that 32 of 35 wells — or 91 percent — contained fecal matter from humans or livestock, the Milwaukee Journal Sentinel reported.” AP writes.
Like the Bergquist story in the Journal Sentinel, AP never mentions the 35 wells were randomly selected from wells already identified as contaminated in previous testing. In fact, the AP story never mentions the results of the 840 wells previously tested until the last sentence of their story.
On Monday, August 5, the Wisconsin State Journal makes the AP story its ‘Top Story’ and attaches this headline–
Study: Private wells in rural southwest Wisconsin are 91% polluted.’
On August 4, the San Diego Union Tribune writes the following headline above the AP story–
‘Fecal matter found in most private wells tested in SW Wis.’
Then, it's the radio stations turn. On Monday, August 5, Mauston-based WRJC posted the following:
‘91% Of SW Wisconsin Private Wells Polluted With Fecal Matter’
“A study by the U.S. Agricultural Research Service finds 91 percent of private wells in southwestern Wisconsin polluted with fecal matter. Follow-up testing is scheduled for next month. Thirty-two of 35 wells contained the contaminants from humans or livestock. Testers found some of the wells contained pathogens, which do cause illnesses like salmonella.”
On August 6, WRN in Central Wisconsin posted this:
‘A warning about well water in southwestern Wisconsin.’
“A new report from the U.S. Agricultural Research Service shows 91-percent of the private wells tested in southwest Wisconsin are contaminated with fecal matter.
“Scientists say the results should be alarming. They say their testing raises serious questions.”
Posted Tuesday, August 6, 2019 7:41 a.m. by Riley Herbert, News Director.
“That’s inaccurate,” said Dr. Mark Borchardt of the recent reporting that claimed 91 percent of the wells in rural southwestern Wisconsin were contaminated. Dr. Borchardt is a USDA microbiologist helping to lead the SWIGG Study.
And the following link will connect the reader to a story in the Crawford County Independent & Kickapoo Scout written by reporter Gillian Pomplun, who attended the meeting in Lancaster.
New SWIGG study results raise serious concerns
The test of the original press release is below:
Embargoed until August 1, 2019 at 9:00 AM.
Mark Borchardt, Mark.Borchardt@ARS.USDA.GOV, 715-387-4943
Joel Stokdyk, firstname.lastname@example.org, 715-384-9673
Ken Bradbury, email@example.com, 608-263-7921
Iowa County: Katie Abbott, Katherine.Abbott@iowacounty.org, 608-930-9893
Grant County: Lynda Schweikert, Lynda.Schweikert@wi.nacdnet.net, 608-723-6377 #4
Lafayette County: Terry Loeffelholz, Terry.Loeffelholz@lafayettecountywi.org, 608-776-3836
SWIGG Study Update – Identifying Sources of Fecal Contamination in Private Wells in Lafayette, Grant, and Iowa Counties
MADISON — The Southwest Wisconsin Groundwater and Geology Study of Grant, Iowa, and Lafayette Counties has entered its second phase: identifying fecal sources of contamination in homeowners’ private wells. Samples were collected in mid-April 2019 from 35 private wells. Wells were randomly selected from those previously found during the study to be contaminated with coliform bacteria or high nitrate (above the drinking water standard of 10 ppm).
Samples were analyzed for pathogens and non-pathogenic microorganisms. The types of microorganisms present can indicate sources of fecal contamination such as human wastewater and livestock manure.
Homeowners received results letters this week, and each county’s conservation department is being provided an update.
Contamination of fecal origin was observed in 32 of 35 wells (91%). There was evidence of both human and livestock fecal contamination of wells, including both cattle and swine manure. The researchers emphasize that the percentage of positive wells from this sampling event is not indicative of a region-wide contamination rate because the sampling focused on wells that had previously shown contamination.
Microorganisms capable of causing illness were also detected, including Salmonella, rotavirus group A, adenovirus, and enterovirus. However, the researchers caution the data only report microorganism detection rates and cannot be easily translated to estimates of health risk.
The percentage of wells that test positive is expected to differ as weather and land use change over time, and it’s too soon to assess which contamination source is more prevalent. Contamination sources are expected to vary seasonally. For example, in Kewaunee County contamination by human wastewater was more common in early spring when groundwater levels were high, while bovine contamination was more common in fall, after manure had been applied.
Tests only identify fecal sources of contamination, like wastewater and manure, and do not capture other potential contaminants or sources of contamination, like fertilizers.
Different wells will be randomly selected for future sampling rounds. The next round is scheduled for early August.
The research team will also carry out geologic studies and analyze well construction practices in the three-county region, with the goal of determining correlations between water quality, geology, and well construction.
According to Ken Bradbury, Director and State Geologist at the Wisconsin Geological and Natural History Survey-University of Wisconsin-Madison Division of Extension, groundwater conditions in southwest Wisconsin differ from those in eastern Wisconsin, and in particular from Kewaunee County, where similar studies were previously conducted. In both areas, wells draw groundwater from aquifers, or water-bearing rocks, composed of fractured dolomite, a type of limestone. In Kewaunee County there is a single dolomite aquifer, but in southwestern Wisconsin there can be as many as three separate aquifers at different depths below the ground surface, each with different water quality. “Before we can completely interpret the results of water sampling, we need to determine the depth and construction of each well sampled so that we can understand the source of water for that well,” said Bradbury.The study was initiated by Grant, Iowa, and Lafayette Counties in collaboration with researchers from the U.S. Department of Agriculture, the Wisconsin Geological and Natural History Survey-UW-Madison Division of Extension, and the U.S. Geological Survey. Support for the study comes from the counties and agencies involved as well as other organizations, including the Lafayette Ag Stewardship Alliance and the Iowa County Uplands Watershed Group.