On January 16, the Oneida County Board passed a resolution calling for the Wisconsin DNR to offer PFAS testing of private wells within a six-mile radius of sites where biosolids, sometimes called sludge, have been spread. It was in response to the high levels of PFAS found in private wells in the Town of Stella. No cause of contamination has been found, but the DNR is looking into sludge spreading as a potential cause.
Part of that resolution called for getting data from the DNR on where those sludge spreading sites are in the county. Land-application (or “spreading”) is a common way for wastewater treatment facilities to dispose of the waste left over from the water purification process. Often, the spreading, which has long been legal, occurs on agricultural fields as a type of fertilizer.
WXPR requested historic data on sludge-spreading in Oneida County from the DNR. It’s available here as an Excel spreadsheet. We also uploaded the data to a Google map to visualize the data.
You can click on the blue points to learn about the sludge spread. The red points are known PFAS contamination sites in the county. You can open the side bar in the upper left hand corner. By selecting “six-mile radius” you can get a general idea of how much of the county would be under the County Board’s suggested testing radius.
The data provided to WXPR and that was used for this map goes back to 1996. There is sludge spreading in the county that pre-dates that year.
It should be noted that the map is not intended to suggest any individual should pursue PFAS testing on their own well. Nor is it offered as an indication the DNR will ultimately pay for such testing. It is simply meant to help visualize the potential impact of the county’s request of the DNR.
The resolution from the Oneida County Board amounts to a request to the DNR to offer PFAS testing for private wells in many areas of the county. The DNR, however, is under no obligation to do so.
What are PFAS?
PFAS, or per- and polyfluoroalkyl substances, are manmade chemicals that have been in use since the 1950s. They’re often referred to as “forever chemicals” because they don’t break down easily.
There are more than 12,000 PFAS chemicals. The most heavily studied are PFOS and PFOA.
They’ve been used in a wide variety of waterproof and non-stick products like raingear and cookware. They’ve also been used in firefighting foam.
PFAS chemicals have been linked to a range of health problems. Those include decreased birth rates, high cholesterol, kidney and testicular cancers, and reduced vaccine effectiveness in children.
Because of these health risks, the Wisconsin Department of Health Services has a recommended PFAS level of no more than 20 parts per trillion [ppt] in drinking water.
The U.S. Environmental Protection Agency (EPA) is in the process of creating national standards for PFAS in drinking water. Its current proposal will limit the maximum amount of PFAS in drinking water to 4 ppt.
PFAS and Biosolids
There are still a lot of unknowns when it comes to PFAS and biosolids.
The EPA is currently developing a risk assessment to better understand the potential public health and ecological risks associated with PFAS in land-applied biosolids. The DNR says this information will be used to inform decisions on the need to regulate biosolids and industrial sludge in the future.
The EPA is expected to have the risk assessment by the end of 2024.
There are currently no state or federal standards for PFAS in biosolids.
The Wisconsin DNR does have an interim strategy for land application of it. The agency said it was “developed using the best information available.”
It does allow for the spreading of sludge with PFAS levels between 20 and 150 parts per billion [ppb] with different levels of restrictions and monitoring.
At or above 150 ppb, the interim strategy calls for alternative treatment or disposal of biosolids besides land application. That’s close to Michigan’s standard. That state previously set its threshold at 150 ppb. It reduced it to 125 ppb of PFOS in biosolids in 2022.
City of Rhinelander wells
In 2019, the City of Rhinelander shut down two of its five municipal wells due to elevated levels of PFAS chemicals. Those wells are located near the Rhinelander-Oneida County Airport.
They’ve been offline since then. The city is in the process of looking for a site to build a new well.
In December of 2019, the Wisconsin DNR labeled the Rhinelander-Oneida County Airport as the responsible party, citing the airport’s storage and use of fire-fighting foam, which contains PFAS. The airport has disputed the designation.
In 2020, WXPR investigated the possibility of sludge spread in the area of the wells as a cause of the contamination. We found the City of Rhinelander spread sludge from its wastewater treatment plant between 1987 and 1993 at the airport.
PFAS in Private Wells
In 2022, the Wisconsin DNR conducted random sampling for PFAS in private wells.
It split the state into 450 sections and sampled one private well at random within each section.
The survey revealed 71% of the wells contained at least one PFAS chemical. About 99% of the contaminated samples had PFAS levels below the state health department's recommended groundwater limits. About 96% of the contaminated samples contained PFAS levels below limits that the EPA is considering adopting.
Agricultural areas had the highest overall concentrations of PFAS.
One of those random sample sites was in the Town of Stella in Oneida County. It came back with combine PFOS and PFOA levels of 15,000 ppt. The Wisconsin Department of Health Services’ safe drinking water limit is 20 ppt.
Town of Stella Private Wells
After that initial well came back with the extremely high levels of PFAS contamination, the DNR expanded its sampling effort. It has offered to pay for PFAS testing of wells within a 2.5-mile radius of the Stella Town Hall.
As of August 2023, 114 private wells had been sampled for PFAS in the Stella area. 81 had at least a trace of PFAS. 49 wells were above the state health recommendation of 20 ppt.
Levels higher than 35,000 ppt have been found in some of those wells.
The Wisconsin DNR has also found concerning levels of PFAS contamination in nearby lakes and rivers.
The DNR has not yet determined a responsible party for the PFAS contamination in the Town of Stella. It is looking into the possibility of sludge spreading as the cause.
According to the data provided to WXPR, Ahlstrom, the current Rhinelander paper mill owners, and the City of Rhinelander have previously spread sludge within a three-mile radius of the town hall.
The DNR tested current biosolids coming from the mill in July. It found what the DNR considers low levels of PFAS. It did not recommend any kind of land use restrictions for it.
Just because current levels didn’t raise concerns with the DNR doesn’t mean past sludge spread didn’t have higher levels of PFAS that could have led to the contamination.
The investigation is ongoing.
Some residents with impacted wells are suing the Rhinelander paper mill.
As that situation is ongoing, the DNR is providing bottled water to residents with PFAS levels above the state’s safe drinking water standard. Residents with affected wells are considering treatment options or digging new wells.
People are also still waiting on test results for PFAS in fish in the lakes in the Stella area. DHS told people at a Stella Town Hall meeting to limit fish consumption from the lakes that had high levels of PFAS until test results come back.
PFAS Testing & Treatment
The latest state budget put aside $125 million to combat PFAS contamination. The Senate passed a bill in November to use the money to create grants to help municipalities deal with the chemicals. The Assembly has yet to take up the bill. Some groups are opposed to the bill, saying it would limit the Wisconsin DNR’s ability to hold polluters responsible.
The State of Wisconsin now requires municipalities to test their water supplies for PFAS. Results can be found in the state’s PFAS Interactive Data Viewer below:
Unlike municipal water supplies, neither the state nor EPA regulates private water wells. This means that private well owners are on the hook for testing costs unless it’s a situation like the one in Stella where in which the DNR offered free testing. There are also no guarantees homeowners can get assistance paying for a new well or treatment system if the PFAS test comes back with elevated levels.
PFAS testing can range from $300-$600. Here is information on UW’s testing.
Locally, Northern Lake Service also offers PFAS testing.
The Wisconsin Well Compensation program can help pay for well replacement and treatment for qualifying homeowners, but it will not cover all the costs.
