What Are PFAS?

Per- and polyfluoroalkyl substances (PFAS) are a large family of over 14,000 synthetic chemicals that share a common structural feature: chains of carbon atoms bonded to fluorine atoms. The carbon-fluorine bond is one of the strongest in organic chemistry, which gives PFAS their defining characteristics: exceptional resistance to heat, water, oil, and chemical degradation.

PFAS have been manufactured since the 1940s for a wide range of applications. Perfluorooctanoic acid (PFOA) was used in the production of non-stick coatings (Teflon). Perfluorooctane sulfonate (PFOS) was the key ingredient in stain-resistant fabric treatments (Scotchgard) and aqueous film-forming foam (AFFF) used for firefighting. Newer short-chain PFAS and replacement compounds such as GenX (HFPO-DA) have been introduced as alternatives to legacy long-chain PFAS.

PFAS enter water supplies through multiple pathways: discharge from manufacturing facilities, use of AFFF firefighting foam at airports, military bases, and fire training facilities, wastewater treatment plant effluent, landfill leachate, and application of PFAS-contaminated biosolids to agricultural land. Because PFAS do not biodegrade, they accumulate in the environment and have been detected in water supplies, soil, wildlife, and human blood samples worldwide.

Health Effects of PFAS in Water

PFAS bioaccumulate in the human body with half-lives ranging from approximately 2 to 8 years for long-chain compounds. Epidemiological and toxicological studies have linked PFAS exposure to a range of adverse health effects.

The most consistent findings include elevated cholesterol levels, thyroid disease, immune system suppression (including reduced vaccine response), reproductive effects (including preeclampsia and reduced birth weight), and certain cancers. PFOA has been associated with kidney and testicular cancer, and the International Agency for Research on Cancer (IARC) classified PFOA as carcinogenic to humans (Group 1) in 2023.

Immunotoxicity is a key concern, particularly for children. Studies have shown that PFAS exposure reduces antibody response to vaccinations, potentially leaving exposed children more vulnerable to infectious diseases. The EPA used immunotoxicity data as the basis for the health advisories of 0.004 ppt for PFOA and 0.02 ppt for PFOS issued in 2022.

Emerging research is also investigating links between PFAS exposure and metabolic effects (obesity, diabetes), endocrine disruption, and liver damage. The full spectrum of health effects from the thousands of PFAS compounds in commerce is still being characterized.

Regulatory Limits for PFAS in Drinking Water

The EPA PFAS rule of 2024 represents the most stringent PFAS regulation globally for individual compounds. Public water systems must conduct initial monitoring by 2027 and achieve compliance by 2029.

How to Test for PFAS in Water

PFAS testing requires highly specialized analytical methods due to the extremely low regulatory limits (parts per trillion). EPA Method 533 and EPA Method 537.1 are the approved methods for drinking water analysis, using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Sampling for PFAS requires PFAS-free sampling equipment, containers, and protocols. Standard laboratory supplies may contain PFAS that can contaminate samples. Samples should be collected in high-density polyethylene (HDPE) or polypropylene containers that have been verified PFAS-free. Field blanks and equipment blanks are essential for quality assurance.

Testing should cover the full suite of regulated PFAS compounds, and many laboratories offer expanded panels that include 30-40 or more individual PFAS compounds to characterize the contamination profile and guide treatment system design.

Treatment Methods for PFAS Removal

Granular Activated Carbon (GAC)

GAC adsorption is the most widely implemented technology for PFAS removal from drinking water. GAC filtration systems are effective for long-chain PFAS (PFOA, PFOS) with empty bed contact times of 10-20 minutes. Short-chain PFAS are less effectively adsorbed by GAC and may require more frequent carbon replacement or alternative technologies. Bituminous coal-based and coconut shell-based carbons have different adsorption characteristics for various PFAS compounds.

Ion Exchange Resins

PFAS-selective single-use anion exchange resins have emerged as a leading treatment technology, offering higher capacity and longer bed life than GAC for many PFAS compounds. These resins are typically used on a single-use (throw-away) basis because PFAS-laden spent resin requires incineration for destruction. Ion exchange systems can be designed for PFAS removal to below the EPA MCLs.

Reverse Osmosis and Nanofiltration

Reverse osmosis and nanofiltration provide the broadest PFAS removal across all chain lengths, including short-chain compounds that are poorly removed by GAC. RO achieves greater than 90% rejection for most PFAS compounds. The concentrate stream, which contains concentrated PFAS, requires proper management and disposal or destruction.

High-Pressure Membranes

For large-scale municipal applications, nanofiltration (NF) membranes offer PFAS removal comparable to RO at lower operating pressures, resulting in reduced energy costs. NF is particularly effective for PFAS compounds with molecular weights above 200 daltons.

Frequently Asked Questions

What are PFAS and why are they called forever chemicals?

PFAS (per- and polyfluoroalkyl substances) are a large class of synthetic chemicals characterized by strong carbon-fluorine bonds that make them extremely resistant to degradation. They are called forever chemicals because they do not break down naturally in the environment and persist indefinitely in water, soil, and biological organisms. PFAS have been manufactured since the 1940s and are found in non-stick coatings, stain-resistant fabrics, firefighting foam (AFFF), food packaging, and many industrial applications.

What is the EPA limit for PFAS in drinking water?

In April 2024, the EPA established the first-ever National Primary Drinking Water Regulation for PFAS. The MCLs are 4.0 parts per trillion (ppt) for PFOA and 4.0 ppt for PFOS individually. For PFHxS, PFNA, and HFPO-DA (GenX), the MCL is 10 ppt each. A hazard index of 1.0 applies to mixtures of PFHxS, PFNA, HFPO-DA, and PFBS. Public water systems have until 2029 to comply.

What is the best treatment for PFAS removal?

The three proven treatment technologies for PFAS removal are granular activated carbon (GAC), anion exchange resins, and reverse osmosis/nanofiltration. GAC is the most widely implemented, particularly for long-chain PFAS like PFOA and PFOS. Anion exchange resins offer higher capacity for certain PFAS compounds. RO provides the broadest removal across all PFAS chain lengths but produces a concentrate stream requiring management.

Need to Remove PFAS from Your Water?

ForeverPure provides commercial and municipal PFAS treatment systems, including GAC adsorbers, PFAS-selective ion exchange systems, RO/NF membrane systems, and complete treatment trains designed to meet the new EPA PFAS MCLs. Our engineering team designs solutions based on your PFAS characterization data, flow requirements, and compliance timeline.

Contact ForeverPure for a customized PFAS removal solution.