Read the full article by Harvard John A. Paulson School of Engineering and Applied Sciences (

“Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) found large quantities of previously undetectable compounds from the family of chemicals known as PFAS in six watersheds on Cape Cod using a new method to quantify and identify PFAS compounds. Exposures to some PFAS, widely used for their ability to repel heat, water, and oil, are linked to a range of health risks including cancer, immune suppression, diabetes, and low infant birth weight.

The new testing method revealed large quantities of previously undetected PFAS from fire-retardant foams and other unknown sources. Total concentrations of PFAS present in these watersheds were above state maximum contaminant levels (MCLs) for drinking water safety.

‘We developed a method to fully capture and characterize all PFAS from fire-retardant foams, which are a major source of PFAS to downstream drinking water and ecosystems, but we also found large amounts of unidentified PFAS that couldn’t have originated from these foams,’ said Bridger Ruyle, a graduate student at SEAS and first author of the study. ‘Traditional testing methods are completely missing these unknown PFAS.’

The research will be published in Environmental Science & Technology.

PFAS—per- and polyfluoroalkyl substances—are present in products ranging from fire retardant foams to non-stick pans. Nicknamed ‘forever chemicals’ due to their long lifespan, PFAS have been building up in the environment since they were first used in the 1950s.

Despite the associated health risks, there are no legally enforceable federal limits for PFAS chemicals in drinking water. The Environmental Protection Agency’s provisional health guidelines for public water supplies only cover PFOS and PFOA, two common types of PFAS. Massachusetts, along with a few other states, has gone further by including six PFAS in their new MCLs in drinking water. But there are thousands of PFAS chemical structures known to exist, several hundred of which have already been detected in the environment.

‘We’re simply not testing for most PFAS compounds, so we have no idea what our total exposure is to these chemicals and health data associated with such exposures are still lacking,’ said Elsie Sunderland, the Gordon McKay Professor of Environmental Chemistry at SEAS and senior author of the paper.

The standard testing methods used by the EPA and state regulatory agencies only test for 25 or fewer known compounds. The problem is the overwhelming majority of PFAS compounds are proprietary and regulatory agencies can’t find what they don’t know exist.

The new method developed by Sunderland and her team can overcome that barrier and account for all PFAS in a sample…”