Story by City of Madison Water Utility
On a warm evening in September 2019 in front of a packed house at Madison’s Winnebago Arts Cafe, Christy Remucal, an associate professor of civil and environmental engineering at the University of Wisconsin-Madison, described her new research project looking at PFAS in the environment. The project had only been underway for one day. More than 100 people showed up to hear about it.
Remucal says the intense interest in PFAS hasn’t stopped since.
“I’ve never gotten more phone calls about an issue ever,” she says. “There is a ton of public awareness. People are hearing about (PFAS), and they’re worried.”
PFAS, or Per- and Polyfluoroalkyl Substances, are a group of widely-used chemicals found in everything from pots and pans to food wrappers, dental floss and firefighting foams. Manufactured by chemical companies since the 1940s, PFAS molecules are made up of a chain of carbon and fluorine atoms linked together. Remucal notes the carbon-fluorine bond is one of the strongest bonds in existence.
“There aren’t any known natural processes that break down these chemicals. There is no known biodegradation process at all,” she says.
No one knows for sure exactly how many different types of PFAS compounds are out there – some estimates put the number at around 6,000. Two of the first types ever created, PFOA and PFOS, have been discontinued from use in the United States amid concern over potential health impacts from high-level exposure. But because they don’t break down, you can find trace amounts of the chemicals just about everywhere, including in the blood streams of most people.
“You look at something like PFOS and an environmental chemist will tell you that it’s going to be bad news,” says Remucal. “You can find these chemicals in something like 98 to 99 percent of Americans.”
Remucal’s research focuses on contamination in and around Marinette, Wisconsin, where industrial wastewater leaving the Tyco fire products plant has contaminated streams, sediment, soil and groundwater. Some nearby private drinking water wells have shown combined PFOA and PFOS concentrations of 73 to 1,900 parts per trillion (ppt) – above both the EPA Health Advisory Level (70 ppt) and Wisconsin Department of Health Services recommended groundwater standard (20 ppt).
“We wanted to take a look at what this contamination means for the surface water … The first phase is focusing right in the Marinette and Peshtigo areas, sampling rivers and tributaries—the water and sediment,” Remucal explains. “The goal is to find out how much of the chemicals stick to the sediment versus staying in the water. Then we want to move a little bit bigger and go out on Green Bay and Lake Michigan and look at both water and sediment again, but on a really big body of water.”
PFAS molecules have a dual nature, they are both hydrophobic (water repellent) and hydrophilic (attracted to water), which makes it difficult to predict how they will move in the environment.
“They’re weird. And that’s what makes them so attractive for industrial applications,” she says. “This part repels water and this part repels oil, and that’s why we use them so much. But it makes predicting their fate challenging, because they don’t always behave the way we think they ought to.”
Discovering PFAS in Madison
The discovery that PFAS had made their way into Madison’s environment happened in 2017, when Madison Water Utility took an unusual step—it tested down to levels far below EPA requirements. MWU had already tested all of the city’s wells for PFAS in 2015 using EPA required methods, and it found nothing. But three years later, after the EPA drastically lowered its own health advisory level for PFOA and PFOS, the utility tested again using advanced methods that could detect ultra-trace levels. It first focused on wells near landfills and Truax Air Field/Dane County Airport, where firefighting foams had been used. Testing found the chemicals at low levels at Well 16 on the west side near an old landfill and Well 15 on the east side near the airport.
Madison Water Utility water quality manager Joe Grande, who oversees all testing, says those first results were eye-opening.
“Maybe I was a little naïve because I wasn’t thinking about what a part-per-trillion or two-parts-per-trillion is as a detection limit,” he says. “We’re talking about three orders of magnitude below where we’re typically measuring organic contaminants. I didn’t really know about the contamination at the airport. I think it was just really the start of our understanding that these compounds are out there.”
Two years and many tests later, Madison Water Utility has discovered low-level detections of multiple PFAS compounds at 14 different wells. All show concentrations well below the EPA Health Advisory and Wisconsin DHS recommended groundwater standard for PFOA and PFOS. But a consistent story is emerging—when you look very hard for these “forever chemicals,” you have a good chance of finding them.
“So many people ask me about our water here in Madison, and I tell them, ‘The data’s online, the utility is doing testing and the concentrations are below what the regulations will likely be,’” Remucal says. “I think Madison Water Utility has been really proactive about testing for these things when they didn’t have to. That’s really a good thing.”
Grande adds that gathering data on the impact of PFAS in Wisconsin’s drinking water is only just beginning.
“Madison has done pretty extensive testing, but many other communities have not. There are all these data gaps that still need to be filled. We’re just scratching the surface on occurrence,” he says.
Author: City of Madison Water Utility