PFAS are a vast group of human-made chemicals that are called “forever” chemicals for a reason – they don’t break down and can impact people's health. They're found in countless products, from firefighting foam to fabric and cookware, and they’ve made their way into drinking water sources in many Wisconsin communities.
Now, the Department of Natural Resources is investigating how much PFAS are present in Wisconsin’s soil.
Crews are collecting samples from 150 sites across the state, including on Milwaukee's north side.
Zach Henderson and Luke Reuteman are looking for the right spot to dig within Havenwoods State Forest.
It’s one of the easier spots the two DNR remediation project managers have tackled. Take the site they’d just come from, "We ended up walking about a quarter-mile and then bushwhacking for another quarter-mile out there looking for the undisturbed area," Reuteman says.
The DNR divided the state into eight chunks and selected locations in state-owned parcels within each to take samples.
"So we have some GIS specialists who do some mapping to show woods and forests, to show that there's a good chance that this is undisturbed — there no anthropogenic changes that have happened here, no filling, no previous buildings," Henderson says.
Reuteman picks up a shovel and started digging.
"We try to take samples right under the root zone, in the top six or so inches," he says.
After slipping on disposable gloves — a fresh pair for each site — Reuteman starts filling three sample tubes.
"One PFAS sample actually takes two tubes. We fill them halfway. We're also collecting PAH samples, or polycyclic aromatic hydrocarbons," Reuteman says.
PAHs are not part of the PFAS family. More on that later.
"Both get shipped on ice. The PAHs to a private lab and PFAS get sent the State Lab [of] Hygiene. Everything’s on ice," Henderson says.
DNR hydrogeologist Erin Endsley is overseeing the project from her base in Superior, Wisconsin.
"Part of that collection process is doing the documentation at the site of what is the soil type, what's the vegetation type, what kind of land use is nearby, do you see anything that could potentially be a source? We chose locations specifically to minimize the potential of contamination. So, we expect to see results that wouldn't be really elevated. If we do see elevated concentrations, we will definitely be evaluating it on a site-by-site basis," she says.
The DNR has been investigating PFAS since 2019, starting with the Yahara Chain of Lakes in Madison, when firefighting foam was found there.
Contaminated private wells were discovered in Marinette and neighboring Peshtigo. The list goes on.
In 2022, "The DNR conducted shallow groundwater studies for PFAS. And our air program, working with the University of Wisconsin, conducted a precipitation study," Endsley says.
The more the DNR can learn about the presence of PFAS – even at low levels – helps determine how and where it’s making its way into drinking water. It also gives the agency the data to advocate for remediation across the state.
"We're trying to figure out what the best path forward is. So I think this study just helps fill in one piece of the puzzle, really," Endsley says.
So, what are PAHs and why were they folded into the project?
"PAHs can be naturally occurring or caused from largely combustion or releases. Primary examples that we have of PAH contamination in Wisconsin, we have a lot of former manufactured gas plants and those sites are known to use coal and other organic contaminant sources to produce manufactured gas and the byproducts of that were very high in PAH contamination. Upland settings, waterways that have been contaminated historically," she says.
Endlsey says except for a study of Milwaukee County Parks land almost a decade ago that found elevated background concentrations of PAHs in soil, there hasn’t been a statewide look at the contaminant.
This soil project will provide the basis for a statewide dataset of PAHs.
She says knowing the concentration of both PAHs and PFAS in areas that have no known source of contamination represents a step forward.
"The science is still evolving on PFAS, on what risk it represents for human health in the environment, and with the lack of leadership on the federal level, it only makes it more complicated on the state level. So I would say our study is just one piece of the overall picture to try and help understand what is happening in our state, to help us move forward with making decisions," Endsley says.
The results of the statewide soil sampling are anticipated in 2027.
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