A large plume of toxic chemicals produced by plants that produce firefighting foam has seeped through the ground to Lake Michigan’s Green Bay, scientists said Tuesday.
The chemicals belong to a family of compounds known as PFAS, or per- and polyfluoroalkyl substances, which are widely used in consumer products ranging from nonstick cookware and waterproof sports equipment to stain-resistant carpets. They are also the main ingredient in firefighting foam. It can accumulate and remain in the human body for a long time, and exposure can cause cancer and other health problems.
Groundwater and streams near Tyco Fire Products in Marinette, Wisconsin, were contaminated with foam from the plant’s testing facility.
University of Wisconsin researchers have been tracking the movement of chemicals in nearby water and streams. In a report published last week, they said a plume had entered Green Bay, which stretches 120 miles (193 kilometers) north-east of Wisconsin and the southern coast of Michigan’s Upper Peninsula.
Water samples showed the plume was about 2.49 miles (4 kilometers) wide, but it was not known how far into the bay it was, said Christy Remucal, professor of civil and environmental engineering.
“A lot of PFAS from that source is going into Lake Michigan and it’s going to be difficult to fill it,” Remucal said in an interview Tuesday. “It’s really scattered, it’s hard to pick up and treat.”
Scientists detected 17 different PFAS chemicals in the bay, one of the largest in the Great Lakes. Thousands of different PFAS compounds have been produced since the 1940s.
Water samples taken along the shoreline in the Marinette area found PFAS concentrations of 250 parts per trillion — higher than levels detected in previous studies of rivers flowing into the bay, Remucal said.
They also exceeded the 70 parts per trillion set by the US Environmental Protection Agency as the drinking water health risk threshold for two common PFAS compounds, known as PFOS and PFOA. The agency last June published new guidelines that set the trigger near zero, saying the chemical is dangerous even at undetectable levels.
Remucal and colleague Sarah Balgooyen used chemical fingerprinting techniques to trace Green Bay PFAS to the Tyco facility.
Wisconsin’s attorney general last year sued Tyco and Johnson Controls, which merged in 2016, over PFAS contamination in the Marinette area.
Tyco said in a statement on Friday that it welcomed the Green Bay study, which was funded by the Wisconsin Sea Grant College Program, and has invested “tens of millions of dollars” to address Marinette pollution. These efforts include an “expansive” groundwater treatment system, underground excavation and work on “long-term drinking water solutions” in the area.
PFAS compounds have been found in all five Great Lakes – Erie, Huron, Michigan, Ontario and Superior. They do not degrade naturally in the environment and move freely in water, unlike contaminants such as PCBs that remain in sediments, Remucal said.
Dan Jones, associate director of Michigan State University’s PFAS Research Center, said the findings are significant because they are based on a wider variety of compounds than most PFAS projects.
“We don’t always measure things like this group,” Jones said, adding that the study was remarkable in tracking pollution from its source through the river, groundwater and Green Bay.
Much is unknown about how PFAS chemicals affect Great Lakes fish, a topic the Michigan State center is exploring, Jones said.
“We know that these compounds are taken up by things that live in the lake … including certain fish that humans consume,” he said. “But we don’t know as much as we want about which fish are collected and why, and whether it’s different for different compounds.”
Our new weekly Impact Report newsletter examines how ESG news and trends are shaping the roles and responsibilities of today’s executives. Subscribe here.