Rainwater in the Great Lakes region contains alarming levels of the toxic chemical PFAS, according to data from a joint Environmental Protection Agency and Canada monitoring network, as detailed in a recent article from EWG.

In the newest data samples, scientists found a combined concentration of 1,000 parts per trillion, or ppt, of PFAS in rainwater collected from Cleveland. While the presence of legacy compounds such as PFOA and PFOS is decreasing in the Great Lakes, the short-chain substitutes are the most prevalent compounds. Since August 2020, scientists with the Integrated Atmospheric Deposition Network (IADN) have been collecting and analyzing rainwater samples from Chicago, Cleveland, Sturgeon Point, N.Y., Sleeping Bear Dunes, Mich., and Eagle Harbor in Michigan’s Upper Peninsula.

“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,” according to Alexis Temkin, Ph.D.,a toxicologist at the Environmental Working Group.

“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.”

Last year, a peer-reviewed study by EWG scientists discovered 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.

Merit Laboratories is a leading national PFAS environmental laboratory, analyzing drinking water, soil, wastewater, groundwater, and other sample matrices, including biosolids and sludge. Analytical methods performed by Merit for PFAS include drinking water by EPA 533, EPA 537.1, and EPA 537 rev. 1.1, biosolids by ASTM D7968-17 with Isotopic Dilution, and soil, wastewater, groundwater, and surface water by ASTM D7979-19 with Isotopic Dilution and ASTM D7968-17.