Foam on Wisconsin water bodies may contain high levels of 'forever chemicals'

MADISON - A new study of Wisconsin lakes found that naturally occurring foam created by churning water could carry high levels of "forever chemicals," warranting caution.

The study, which involved researchers from the University of Wisconsin PFAS Center of Excellence, looked at the levels of PFAS in foam that typically collects along the shores of water bodies, and in the air-water interface, or the very top of the water.

Christine Remucal, a professor of civil and environmental engineering at UW-Madison, graduate student Sarah Balgooyen and other researchers looked at foam and surface water samples collected between 2020 and 2023, from areas across the state. Included in the study were Lakes Mendota and Monona in Madison, the Menomonee and Kinnickinnic Rivers in Milwaukee and the Bay of Green Bay, which is a part of Lake Michigan. Foam was the main focus in Madison, while in other places the focus was surface water sampling.

The samples were compared against samples taken from deeper within the water body.

"The big things we found were that the concentration of PFAS in the foams was quite a bit higher than what was in the water," Remucal said. "So for example, depending on the chemical and depending on the lake, the concentrations in foam were 50,000-70,000 times higher in the foams compared to the water."

The chemicals collect in foam and at the surface because of their molecular structure, Remucal said. They like to hang out where there is a large amount of the water's interface shared with the air.

"If you think about a foam, it's a bunch of little tiny bubbles," she said. "And that's all interface, so PFAS really like to accumulate there."

But not all foam automatically contains PFAS. Foam naturally occurs when air is mixed into the water — like downstream of a dam or on a very windy day.

"The presence of foam doesn't exactly indicate PFAS," Remucal said. "The reason why this is a concern is because PFAS are toxic at really low levels. So the concentrations we've measured are of concern, even though they make up a small fraction of what's actually in the foam."

To stay safe, Remucal said to be aware of advisories for the chemicals in the water and to stay away from the foam. Keep your pets out of it and don't allow curious children to scoop it up and put it in or near their mouths.

PFAS largely get into the human body through the consumption of drinking water or eating contaminated fish, so make sure to follow fishing guidelines and wash your hands as soon as possible if you do come into contact with foam, she said.

"My general advice is to not play with the foam in general," she said. "Stay away from it."

Zach Wood, a public information officer for the Department of Natural Resources, said the agency is reviewing the study and will assess how it fits with their ongoing PFAS response activities.

"The findings in this study support the DNR’s advice to avoid contact with or ingestion of foam on waterways. Foam can develop naturally on waterways and it is impossible to tell if foam contains PFAS just by looking at it," he said in an emailed statement. "Regardless of if foam is the result of natural causes or because of PFAS contamination in the surface water, it can concentrate a variety of pathogens and synthetic compounds that present risk to human health."

Remucal and the PFAS Center of Excellence are also working on a study examining the amount of the chemicals in ice. That study should be released later this year.

Center researchers were also involved in a study released last year that traced a plume of PFAS in the Bay of Green Bay back to Tyco Fire Products in Marinette . The study found the unique "fingerprint" of the PFAS found in the bay, and connected it to the facility, which was known for mixing firefighting foam containing the chemicals.

That fingerprinting technique could be used in the future to help identify the parties responsible for PFAS contamination.

More: 'Forever chemicals' from Marinette firefighting foam plant are in Lake Michigan, UW researchers find

What are PFAS?

PFAS, or per- and polyfluoroalkyl substances , are a family of man-made chemicals used for their water- and stain-resistant qualities in products like clothing and carpet, nonstick cookware, packaging, cosmetics and firefighting foam.

The family includes 5,000 compounds, which are persistent, remaining both in the environment and human body over time.  The chemicals have been linked to types of kidney and testicular cancers, lower birth weights, harm to immune and reproductive systems, altered hormone regulation and altered thyroid hormones.

Laura Schulte can be reached at leschulte@jrn.com and on X at @SchulteLaura .

This article originally appeared on Milwaukee Journal Sentinel: Foam on Wisconsin water bodies may contain high levels of 'forever chemicals'