Update: Mosinee blending 2 wells together to mitigate PFAS levels in some of its drinking water, still above new EPA advisory

Curiosity is growing among municipalities, businesses, and individuals as more communities...
Curiosity is growing among municipalities, businesses, and individuals as more communities around Wisconsin learn their drinking water is contaminated with what are known as, “forever chemicals,” per- and polyfluoroalkyl substances, or PFAS.(WSAW Tom Zurawski)
Published: Jun. 28, 2022 at 7:01 PM CDT
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MOSINEE, Wis. (WSAW) - Mosinee municipal wells have been found with PFAS levels above the Environmental Protection Agency’s new health advisory limits of nearly zero.

The EPA’s new advisory came out on June 15, which states that some negative health effects may occur at concentrations near zero for the compounds PFOA and PFOS (0.004 and 0.02 parts per trillion respectively).

The city re-tested its wells on the east side on May 4 and June 2 after finding mixed results in its previous round of testing. At the time, the Wisconsin Department of Health Services was continuing to recommend its health advisory of keeping the combined PFOA and PFOS levels below 20 parts per trillion.

According to test results of the east side wells the city provided to 7 Investigates, one operating well tested at 38.72 ppt in May. So, City Administrator Jeff Gates said they combined water from that well with another operating well in an attempt to lower the levels. The blending lowered the levels to 17.97. The city tested its wells on the west side in its first round of testing and stated no PFAS was detected. Wells on the west side are run through the city’s treatment plant, which has a granulated carbon filter. That filter, while installed to reduce high manganese in the water, also filters out some PFAS.

However, all wells that were tested on the east side are at levels above the new EPA health advisory levels.

Gates said the city is working on a plan and doing research to continue mitigating the levels on the east side. They hope to have more details following the city board meeting in July.

In February, the state’s Natural Resources Board voted to approve its first drinking water standard for PFAS chemicals, placing it at 70 ppt, which is what the EPA’s health advisory limit was at in 2016. That was despite the Department of Natural Resources and DHS recommending the lower limit of 20 ppt.

The NRB voted down the 20 ppt recommended PFAS groundwater standard due to concerns that the Wisconsin Manufacturers and Commerce brought up related to the state’s economic impact analysis. The EPA does not regulate groundwater, but it is closely tied to drinking water.

correction: A previous version of this story incorrectly reported the levels of PFAS in Mosinee's blended mitigation as 36.5 ppt, which would be above the state's recommended health limit. It has since been corrected to reflect the correct result of 17.97 ppt, which is below the state's recommended health limit of 20 ppt.

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