News Release 24-Sep-2025

Sea foam could contain more ‘forever chemicals’ than water below, study finds

Peer-Reviewed Publication

American Chemical Society

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A field study observed higher levels of forever chemicals in sea foam than in water along part of North Carolina’s coast.

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Credit: Emily Donovan, adapted from Environmental Science & Technology 2025, DOI: 10.1021/acs.est.5c03600

Sea foam is a common sight along the coastline as breaking waves churn up air and algae. Now, a study in ACS’ Environmental Science & Technology reports that sea foam from several beaches along North Carolina’s coast contain higher levels of per- and polyfluoroalkyl substances (PFAS) compared to the water below. Some foam samples had more PFAS than what is allowed in drinking water, highlighting the need to clean up and reduce environmental PFAS pollution.

“Our research shows that sea foam along North Carolina’s coast can concentrate PFAS to levels thousands of times higher than the surrounding seawater,” says Jeffrey R. Enders, the study’s corresponding author. “Monitoring these coastal environments is critical because contact with contaminated foam could pose unexpected risks to people and ecosystems.”

Depending on the day, ocean waves may release large bursts of sea spray or create a sudsy, floating foam. Past studies have shown that sea spray can carry PFAS into the air, if these forever chemicals are in the water, exposing people to contaminants that can lead to adverse health effects. But the transfer of forever chemicals into sea foam hasn’t been widely studied. Therefore, a grassroots community group (Clean Cape Fear) in North Carolina collected sea foam from coastal beaches and performed preliminary testing. The initial work found that some foam samples contained PFAS at significantly higher concentrations than the current parts-per-trillion (ppt) drinking water limits regulated by the U.S. Environmental Protection Agency (EPA). This result prompted Enders and colleagues to expand the investigation to 13 places along the mouth of the Cape Fear River and the nearby Atlantic coastline.

The researchers collected water and sea foam samples at each location, screened them for 49 common PFAS, and detected 35 individual PFAS across the samples. Each water sample exceeded 1 ppt total PFAS, with some reaching nearly a thousand times higher. Several foam samples had individual forever chemicals present at more than 1 million ppt, including perfluorooctane sulfonic acid (PFOS) — one of six PFAS explicitly regulated by the EPA — which was present at 8 million ppt. Additionally, most PFAS were more concentrated in foam than in the water, reaching levels that were tens to thousands of times higher in many locations. The researchers also identified new PFAS in the samples, which they say likely came from nearby manufacturing facilities.

These findings show that PFAS concentrations in sea foam are higher than in regular sea water, potentially impacting human and animal exposures. The researchers conclude that this work underscores the need to reduce regional PFAS pollution and expand coastal monitoring for contamination.

The authors acknowledge funding from the National Institute of Environmental Health Sciences of the National Institutes of Health.