Global rainwater is now contaminated with ‘forever chemicals.’ What can we do about it?

rain drops splashing on pavement
Photo by Matthew Modoono/Northeastern University

Rainwater contaminated by toxic chemicals called per- and polyfluoroalkyl substances, or PFAS, is now a global problem, according to new research published in Environmental Science & Technology.

The Stockholm University study found that levels of PFAS contamination are so persistent and widespread that even the most sparsely populated regions of the world, such as Antarctica and the Tibetan plateau, contained levels of the toxic “forever chemicals” that surpassed even the most “stringent” existing guidelines, the authors said. 

“There is nowhere on Earth where the rain would be safe to drink, according to the measurements that we have taken,” Ian Cousins, a professor at the university and lead author of the study, said recently. 

PFAS forever chemicals, so named because they do not easily degrade, accumulate in the body once ingested, potentially leading to a range of health problems.

headshot of phil brown outside
Phil Brown, director of the Social Science Environmental Health Research Institute and university distinguished professor of sociology and health sciences. Photo by Ruby Wallau/Northeastern University

The news is sure to place a burden on water suppliers, says Phil Brown, university distinguished professor of sociology and health sciences and director of the Social Science Environmental Health Research Institute at Northeastern.

“Drinking and municipal water suppliers are going to have a very hard time figuring out what to do with this,” he says. 

The report comes after the Environmental Protection Agency announced new health advisories for PFAS in June as part of the Biden administration’s strategic plan to deliver more clean water to U.S. communities. Those advisories, which Brown says are different from regulatory caps, were lowered after the chemicals were found to be associated with “reduced immune system response to childhood vaccines.”

“These are thousands of times lower than what we’ve had so far—and they aren’t regulatory,” he says. “But they are part of the pathway of getting regulatory and maximum contaminant levels.”

But, Brown says, in all likelihood “no one is going to be able to meet” these new levels. 

“What it does do is it puts people on alert that there are actual health effects—even at these lower levels,” Brown says. 

The report also comes amid new research published in JHEP Reports that found that high levels of PFAS exposure is linked to increased risk of liver cancer, or non-viral hepatocellular carcinoma. One particular chemical subset of PFAS, called perfluorooctane sulfonic acid, or PFOS, is strongly connected to the disease.

Jesse Goodrich, a postdoctoral researcher in the Department of Population and Public Health Sciences at the Keck School of Medicine, said in a statement that the study is the first to confirm a link using human samples.

“Liver cancer is one of the most serious endpoints in liver disease and this is the first study in humans to show that PFAS are associated with this disease,” he said.

Brown says that exposure to high levels of PFAS can also lead to decreased fertility, developmental delays in children, and prostate, kidney, or testicular cancer. There’s also lots of evidence linking PFAS toxification with various metabolic disorders, as well as obesity and diabetes, he says. 

Researchers at Northeastern launched an interactive, online map of the U.S. that pinpoints areas of concern due to high levels of the chemicals. 

What’s being done to counter the prevalence of PFAS?

Brown says there are many efforts underway to combat PFAS proliferation, from the development and refinement of filtration technologies designed to trap the substances in the water, to “thermal treatments” that essentially incinerate the chemicals. 

Most importantly, he says, is holding large corporations accountable for their outsized role in manufacturing products that contain PFAS, which can be found in everything from clothing products and cooking appliances, to dental floss, firefighting foam and food packaging.  

“The best thing we can be doing is cutting it off at the source,” he says.

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