A groundbreaking study has revealed that sea foam along the coast of North Carolina harbors significantly higher concentrations of per- and polyfluoroalkyl substances (PFAS), commonly referred to as “forever chemicals,” than the seawater beneath it. Published in the renowned journal Environmental Science & Technology, this research highlights an unexpected and concerning route by which PFAS can accumulate in coastal environments, potentially amplifying exposure risks for both humans and wildlife.
Sea foam forms naturally when turbulent breaking waves mix air, organic matter, and dissolved substances, creating a frothy layer that is often visible along sandy beaches. While sea spray has previously been studied as a medium capable of transporting airborne contaminants, the role of sea foam in concentrating and possibly dispersing PFAS has been largely unexplored until now. PFAS are a large family of synthetic chemicals used extensively in industrial applications and consumer products for their water- and grease-resistant properties. Due to their chemical stability and resistance to degradation, these substances persist in the environment and accumulate in living organisms, earning them the nickname “forever chemicals.”
The impetus for this study began with observations by Clean Cape Fear, a grassroots environmental group in North Carolina, which collected sea foam samples from local beaches. Initial analyses revealed alarmingly high PFAS concentrations in the foam, surpassing the strict regulatory limits set by the U.S. Environmental Protection Agency (EPA) for drinking water. This prompted lead researcher Jeffrey R. Enders and his team to systematically survey 13 sites along the mouth of the Cape Fear River and the adjacent Atlantic shoreline. Their expanded sampling effort involved measuring the levels of 49 different PFAS compounds in both water and foam samples.
The results were striking: all water samples contained total PFAS concentrations exceeding 1 part per trillion (ppt), with some readings nearly a thousand times greater. In foam samples, individual PFAS compounds were detected at staggering levels, reaching concentrations over one million ppt. Notably, perfluorooctane sulfonic acid (PFOS), one of the six PFAS substances regulated by the EPA due to its toxicity, was present at concentrations as high as eight million ppt in sea foam samples. These findings suggest that foam acts as a potent concentrator of PFAS compounds, with levels tens to thousands of times higher than the surrounding seawater.
The chemical mechanisms behind this enrichment likely involve the surface-active nature of PFAS molecules. These compounds have both hydrophobic and hydrophilic segments that cause them to adsorb at interfaces, such as the air-water boundary found in sea foam. As waves churn and organic matter accumulates, this interface becomes a hotspot where PFAS can partition and concentrate far beyond their dissolved levels in the bulk water. This phenomenon raises new concerns because coastal environments serve as a nexus between terrestrial pollution sources and marine ecosystems, intensifying the bioavailability of harmful contaminants.
Emerging evidence also points to the possibility that sea foam can facilitate the transfer of PFAS into the atmosphere. Previous studies have demonstrated that sea spray aerosol can carry these chemicals inland, serving as a vector for human and ecological exposure to airborne PFAS. Since foam formation often precedes or occurs concurrently with sea spray events, the high PFAS content found in foam might represent a reservoir that, when dispersed by wind and waves, releases contamination into the air. This dual pathway intensifies the challenge of managing PFAS pollution in coastal regions and underscores the urgency for environmental monitoring.
The discovery of new, previously unidentified PFAS in the collected samples further complicates the environmental picture. These novel compounds are likely linked to local industrial activities, suggesting ongoing inputs of PFAS from manufacturing facilities near the Cape Fear River. The complex mixture of legacy and emerging PFAS compounds detected in the study highlights the difficulty regulatory agencies face in keeping pace with the evolving chemical landscape. Targeted strategies are needed to identify and control sources as well as to understand the ecological fate of these substances.
Beyond chemical quantification, the study raises significant public health implications. People who frequent coastal areas—whether for recreation, fishing, or occupational purposes—may be exposed to concentrated PFAS through direct skin contact with foam or inhalation of PFAS-laden aerosols. Marine organisms, from microorganisms to larger fauna, could also bioaccumulate these substances, potentially introducing PFAS into food webs and further amplifying ecological risks. This multifaceted exposure highlights the need for interdisciplinary study combining chemistry, toxicology, and environmental health sciences.
The researchers advocate for enhanced regional monitoring programs incorporating sea foam alongside traditional water sampling. Such expanded surveillance would improve detection of contamination hotspots and help track temporal variations linked to weather, industrial discharges, or remediation efforts. Moreover, integrating foam analysis into environmental assessments could provide a more comprehensive understanding of PFAS dynamics in coastal ecosystems, enabling better-informed risk assessments.
This investigation is part of a growing body of scientific efforts aimed at unraveling the complex environmental behavior of PFAS. It also aligns with increasing global regulatory scrutiny as governments implement more stringent limits on PFAS in water, air, and consumer products. The findings support calls for reducing PFAS emissions at the source, improving wastewater treatment technologies, and fostering the development of safer chemical alternatives.
Funding from the National Institute of Environmental Health Sciences underscored the importance of this work, facilitating the advanced analytical techniques and field campaigns necessary to detect and characterize PFAS at ultra-trace levels. Sophisticated instrumentation capable of distinguishing dozens of PFAS compounds continues to be vital for advancing scientific knowledge and informing regulatory decisions.
In conclusion, the study shines new light on a previously overlooked environmental compartment: sea foam as a concentrated reservoir of hazardous “forever chemicals.” The discovery that PFAS levels in foam dramatically exceed those in seawater demands urgent attention from scientists, policymakers, and the public alike. Mitigating PFAS contamination in coastal regions will require collaborative efforts that span scientific disciplines and regulatory frameworks, aiming to protect both ecosystems and human communities from these persistent pollutants.
Subject of Research: Per- and polyfluoroalkyl substances (PFAS) concentrations and distribution in sea foam and seawater along the North Carolina coast.
Article Title: “Detection and Quantitation of Per- and Polyfluoroalkyl Substances in North Carolina Sea Foam and the Corresponding Sea Water”
News Publication Date: 27-Aug-2025
Web References:
10.1021/acs.est.5c03600
References:
Environmental Science & Technology, American Chemical Society.
Image Credits: Emily Donovan, adapted from Environmental Science & Technology 2025, DOI: 10.1021/acs.est.5c03600
Keywords: Chemistry, Pollution, Water pollution, Oceanography
