Fish can gather significant amounts of per- and polyfluoroalkyl substances (PFAS), even in areas distant from contamination sources, as shown by a recent study. This research emphasizes the necessity for enhanced monitoring in watersheds impacted by major PFAS sources, like military bases throughout the country that have been polluted due to the use of PFAS-laden foams in fire training and firefighting efforts.
A new study from researchers at The Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) demonstrates that fish can absorb significant levels of per- and polyfluoroalkyl substances (PFAS), even when located far from contamination sites. This study calls for improved monitoring in watersheds influenced by substantial PFAS sources, such as military bases nationwide that have been affected by the application of foams containing PFAS during fire training and firefighting operations.
“This study highlights the critical need for thorough monitoring of PFAS in aquatic environments, especially in areas where freshwater fishing is vital for both recreational and subsistence fishers,” remarked Elsie Sunderland, the Fred Kavli Professor of Environmental Chemistry and a Professor of Earth and Planetary Sciences at SEAS, who is the senior author of the study. “The health risks linked to PFAS extend beyond immediate contamination areas and can impact communities situated far away from known sources. To safeguard these communities, it is essential to assess PFAS levels in fish at locations hydrologically connected to recognized contamination sites and to establish consumption advisories.”
The findings were published in Environmental Science & Technology.
PFAS, often referred to as “forever chemicals” due to their durability in the environment, comprise a group of thousands of man-made chemicals that are commonly used for their non-stick, water-repellent, and stain-resistant properties. These substances have infiltrated our water, soil, and food supply, affecting more than 98-99% of the U.S. population. Although the Environmental Protection Agency (EPA) has set federal drinking water standards for six PFAS substances associated with health risks, no federal regulations exist for PFAS levels in food. Massachusetts has issued health-based consumption limits for one PFAS commonly found in fish (PFOS), but recent studies indicate that many other PFAS also build up in fish tissues. Freshwater fish and shellfish, which are diet staples for many, often have elevated concentrations of these “forever chemicals.”
The research team analyzed fish and shellfish species collected from ponds, rivers, and bays on Cape Cod, Massachusetts, situated downgrading from a military base that has historically utilized PFAS-containing firefighting foams, known as AFFF (aqueous film forming foams).
“Across the U.S., numerous military bases and airports extensively employed AFFF for firefighting and fire training, resulting in a legacy of contamination in various watersheds,” stated Heidi Pickard (’24), who recently completed her PhD at SEAS and is the lead author of the study derived from her doctoral research. “While PFAS contamination in surface and groundwater near these locations is well-documented, its implications for downstream ecosystems essential to recreational and subsistence fishing are less understood.”
The outcomes were alarming: PFAS levels in fish tissues remained shockingly high, even as far as 8 km from the military base. Although concentrations decreased somewhat with distance, fish filet samples routinely surpassed state guidelines for safe consumption based on PFOS levels alone, not considering other PFAS found in the samples.
The researchers discovered that a significant amount of PFAS contamination goes unnoticed by standard monitoring methods, which typically focus on a limited set of PFAS compounds. To fully understand the extent of PFAS contamination and its dangers, environmental monitoring initiatives and fish consumption guidelines must encompass a broader array of PFAS substances.
