In parts of the U.S., it’s raining PFAS

Monitoring data show rainwater tainted with phased-out and new toxic "forever chemicals"

WASHINGTON – As first reported by Garret Ellison at MLive, preliminary data from a joint Environmental Protection Agency and Canada monitoring network show rainwater in the Great Lakes region contains alarming levels of the toxic “forever chemicals” known as PFAS. 

Scientists with the Integrated Atmospheric Deposition Network of Great Lakes monitoring stations, or IADN, measured 38 different PFAS compounds in air and rainwater. An early analysis of raw data shows PFAS to be a major contaminant in regional rain and snow.

Since August 2020, IADN has collected and analyzed rainwater samples from Chicago, Cleveland, Sturgeon Point, N.Y., Sleeping Bear Dunes, Mich., and Eagle Harbor in Michigan’s Upper Peninsula.

Analyzing the latest raw data samples, the scientists found a combined concentration of 1,000 parts per trillion, or ppt, of PFAS in rainwater collected from Cleveland.

Phased-out PFAS and their so-called short-chain replacements were detected in all the samples. While the presence of legacy compounds such as PFOA and PFOS is decreasing in the Great Lakes, the short-chain substitutes are the most abundant compounds.

“The more we learn about the PFAS short-chain replacements, the more the evidence mounts of their close similarity to the phased-out legacy compounds,” said Alexis Temkin, Ph.D., a toxicologist at the Environmental Working Group. “These substitutes share many characteristics with first-generation PFAS, including many of the same health hazards and vast contamination of our environment, and the rainwater samples support those findings.”

PFAS are often called forever chemicals because they are incredibly persistent, never break down in the environment and build up in our blood and organs. They’ve even been detected in the snow and ice samples near the summit of Mount Everest and in polar bears’ blood. 

PFAS are a large family of chemicals linked to harm to the immune system, such as reduced vaccine efficacy; harm to development and the reproductive system, such as reduced birth weight and impacts on fertility; increased risk of certain cancers; and effects on metabolism, such as changes in cholesterol and weight gain.

“We test water samples for PFAS and what our research continues to show is the more we look for PFAS, the more we find them,” said Sydney Evans, EWG science analyst. “This is a national crisis as PFAS pollution continues to grow in our drinking water.”

In April, Jennifer Faust, an assistant professor at Wooster College, told an American Chemical Society meeting how PFAS are transported in the atmosphere and deposited far from the source via precipitation. She highlighted tests that found 17 different PFAS compounds in rainwater collected in summer 2019, expressing surprise at finding legacy and short-chain PFAS equally present in rainwater.

This new IADN analysis also builds on a 2019 study of the Great Lakes region confirming PFAS’ widespread presence in rainwater. The analysis also suggested that new federal regulation of the chemicals could reduce their levels in the environment.

“These toxic chemicals are so ubiquitous that it’s now literally raining PFAS,” said Scott Faber, EWG’s senior vice president for government affairs. “While we’re heartened that the Biden administration and the EPA continue to make PFAS a priority, to truly tackle this national PFAS pollution crisis, we need a whole-of-government approach that includes the Department of Defense, the Food and Drug Administration and the Federal Aviation Administration.  

Last year, a peer-reviewed study by EWG scientists found PFAS contamination is likely in drinking water supplying more than 200 million Americans. As of January, 2,337 locations in 49 states are known to have PFAS contamination. Regulating PFAS chemicals as a class is the only way to protect public health.


The Environmental Working Group (EWG) is a nonprofit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through research, advocacy and unique education tools, EWG drives consumer choice and civic action. 

Disqus Comments

Related News

Continue Reading