Tributaries play key role in feeding ‘forever chemicals’ into Great Lakes: study

Tributary rivers that feed into Lake Michigan play a critical role in shuttling cancer-linked “forever chemicals” into the Great Lakes system, a new study has found.

Scientists quantified the presence of 10 types of perfluoroalkyl acids (PFAAs) in both water and sediment of 41 tributaries to Green Bay of Lake Michigan, according to the study, published recently in the American Chemical Society’s ES&T Water journal. The Great Lakes are the world’s largest source of fresh water, providing drinking water to more than 40 million people in the U.S. and Canada, according to the study.

PFAAs are members of the per- and polyfluoroalkyl substances (PFAS) umbrella group — which contains thousands of compounds and are known for their propensity to linger in the human body and the environment.

“Understandably, there is a heightened interest in the levels of PFAS in drinking water,” co-author Sarah Balgooyen, a postdoctoral researcher at the University of Wisconsin-Madison, said in a statement. “PFAS have been linked to a number of ill human health effects, including cancer.”

Most known for their presence in industrial discharge and jet-fuel firefighting foam, PFAS are also ingredients in a variety of household products and have been linked to kidney cancer, thyroid disease and other illnesses. 

While studying the water and sediment samples from the area, the researchers found that the Fox, Menominee and Peshtigo rivers contribute two-thirds of the total tributary PFAA release into Green Bay.

The sources of these chemicals, the scientists said, are probably linked to a firefighting foam manufacturer, industrial activity and airports that use the foam on their runways. 

In addition to looking at tributary discharge, the scientists also determined that tributary sediments could contribute to the release of PFAAs through a process called desorption — meaning a contaminated riverbed could become a source of PFAA pollution even if the water above it is clean.

“Our study is bringing some much-needed answers to not only the people who live around the bay of Green Bay, but also to all of the Great Lakes communities because it’s an interconnected water system,” Christy Remucal, a University of Wisconsin-Madison professor of civil and environmental engineering, said in a statement.

“These findings could also be extrapolated to understand the conditions surrounding thousands of other tributaries that flow into the five lakes,” she added.