What are PFAS?
PFAS is an umbrella term that includes both perfluoroalkyl and polyfluoroalkyl substances. The distinction between these two lies in the degree to which carbon atoms in their chemical structure are fluorinated:
- Perfluorinated chemicals have carbon atoms that are fully bonded to fluorine atoms.
- Polyfluorinated chemicals have at least one carbon atom that is not completely fluorinated.
This fluorination process gives PFAS their remarkable properties—water, grease, and stain resistance—making them highly desirable in a range of consumer and industrial applications.
Uses of PFAS
PFAS have been used since the 1950s in a wide range of products due to their unique properties, including:
- Cookware: Non-stick coatings
- Clothing and carpets: Stain resistance
- Firefighting foam: Foam suppression
- Paper products: Water and grease resistance
- Personal care products: Waterproofing
However, this versatility has come at a cost. PFAS have now been detected in water supplies worldwide, raising concerns about their environmental impact and potential risks to human health.
Common PFAS and Their Presence in Drinking Water
There are thousands of PFAS compounds, but some of the most commonly detected in drinking water and the environment include:
- Perfluorooctanoic acid (PFOA)
- Perfluorooctanesulfonate (PFOS)
- Perfluorobutanoic acid (PFBA)
- Perfluorohexanoic acid (PFHxA)
- Perfluoroheptanoic acid (PFHpA)
- Perfluorononanoic acid (PFNA)
- Perfluoroundecanoic acid (PFUnDA)
- Perfluorohexanesulfonic acid (PFHxS)
Studies on PFAS in drinking water have primarily focused on PFOA and PFOS, which are the most commonly detected and have been extensively studied for their health risks. However, other PFAS compounds have also been found in water sources. Recognizing the threat, the U.S. Environmental Protection Agency (EPA) has developed a validated method for testing PFAS in drinking water as part of its broader PFAS Action Plan.
The Challenges of Detection and Global Distribution
PFAS contamination is pervasive in surface water (SW) and groundwater (GW) worldwide. High levels have been detected in regions with significant industrial activity or frequent firefighting foam usage, such as airports. However, the concentration of research efforts in these areas—especially in Australia, China, Europe, and North America—may skew perceptions of PFAS distribution. It’s likely that PFAS contamination is more widespread than current data suggests, but unsampled regions remain under-researched.
Interestingly, contamination is not limited to areas near PFAS manufacturing facilities. For example, Australia does not produce PFAS but still has highly contaminated sites due to its use in firefighting activities. This highlights the broad-reaching impact of PFAS, making them a global issue.
PFAS: A Complex Family of Chemicals
The PFAS family includes hundreds of chemicals, each with unique properties. While perfluoroalkyl substances have all carbon atoms (except the last) bonded to fluorine atoms, polyfluoroalkyl substances have at least one carbon atom that is not fully fluorinated. This structural difference leads to a variety of chemical behaviors and environmental persistence across the PFAS family.
In the past, the abbreviation “PFC” (perfluorinated chemicals) was commonly used to refer to PFAS. However, this term is now considered outdated and confusing, as “PFC” also refers to perfluorocarbons, which are unrelated chemicals primarily associated with greenhouse gases. Despite this change, older materials may still use the “PFC” designation, but the term has since been retired from official use.
Environmental and Health Concerns
PFAS are highly resistant to degradation, which is why they are often called “forever chemicals.” Once introduced into the environment, they do not easily break down, leading to long-term contamination of soil, water, and air. They have been found to accumulate in both humans and wildlife, posing significant health risks, including potential links to cancer, thyroid disorders, and immune system dysfunction.
Given the global nature of PFAS contamination, continued research and regulation are crucial to understanding and mitigating their impact. The U.S. EPA’s testing methods represent a key step forward, but the scale of the issue demands a comprehensive international response to limit exposure and manage contaminated sites.
Conclusion
PFAS are a complex and pervasive group of chemicals that have been used in a wide range of products for decades. While their resistance to water, stains, and heat made them a revolutionary discovery, their long-lasting presence in the environment has become a growing concern. As research and regulatory efforts intensify, it is crucial to continue exploring the full extent of PFAS contamination and develop strategies to safeguard both the environment and public health from these “forever chemicals.”
References
Wang, Z., Hou, J., Zhang, Y., et al. (2021). Global distribution and environmental risks of perfluoroalkyl substances (PFAS). Environmental Science & Technology, 55(11), 7871-7883.
Ackerman Grunfeld, D., Gilbert, D., Hou, J., et al. (2024). Underestimated burden of per- and polyfluoroalkyl substances in global surface waters and groundwaters. Nature Geoscience, 17(5), 340–346. https://doi.org/10.1038/s41561-024-01402-8.
Buck, R. C., Franklin, J., Berger, U., et al. (2017). Perfluoroalkyl substances in the environment: Sources, fate, and occurrence. Environmental Science & Technology, 51(18), 10582-10611.
Lindstrom, A. B., Giesy, J. P., Strynar, M. J., et al. (2018). Global contamination of drinking water by perfluoroalkyl substances (PFAS). Environmental Science & Technology, 52(18), 10122-10135.
National Institute of Environmental Health Sciences. (n.d.). Perfluorinated Chemicals (PFCs) [https://www.niehs.nih.gov/research/supported/exposure/pfas].
U.S. Environmental Protection Agency. (2020, February 11). Pfas Explained [https://www.epa.gov/pfas/pfas-explained].