What makes PFAS particularly challenging is that many of them are chemically and biologically persistent, and some are highly mobile in the environment.
And current remediation technologies are marginally effective at removing all PFAS from soil and water. Also, there are thousands of PFAS compounds, most of which have little or no published data on toxicity, mobility, or successful treatment approaches. The standards being debated are extremely stringent (up to 1,000 times lower than for other pollutants), and public, regulatory and political pressures are driving an expedited timeline for remedial solutions.
PFAS in Drinking Water, Groundwater and Wastewater
Current U.S. Environmental Protection Agency guidance for PFAS are provided for PFOA and PFOS. In the absence of federally-mandated standards for PFAS, many states have established Maximum Contaminant Levels (MCLs) for PFOA and PFOS, as well as several other PFAS compounds. Many of these MCLs are regulated and often lower than the Federal guidance. This has generated the need for treatment of drinking water to meet both current federal guidance, as well as state-level standards. As state requirements continue to be developed, the quantity of water requiring treatment increases.
Additionally, many municipal wastewater treatment plants (WWTPs) have been identified to have PFAS in their influent. Recent studies have shown PFAS in WWTP influents to be in the tens to hundreds of nanograms per liter (ng/L) – well above guidelines. Conventional sewage treatment methods do not efficiently remove PFAS, and in many cases allow them to be discharged to local surface water.
PFAS have also been found in domestic sewage sludge. Application of biosolids as a soil amendment can result in a transfer of PFAS to soil, which can then leach to groundwater or be available for uptake by plants and soil organisms.
PFAS at Military and Civilian Airports
Unique PFAS chemical properties were exploited for aqueous film‑forming foams (AFFF), which efficiently extinguish class B (flammable liquid) fires. AFFF was used extensively by first responders, including Aircraft Rescue and Firefighting (ARFF) teams, as well as at chemical facilities, fuel storage areas, and training facilities. Potentially impacted areas include current or historical AFFF training areas; equipment maintenance and test areas; disposal areas and treatment lagoons; drainage channels, ditches, and outfalls; wastewater plants, piping, and sludge; and crash sites and hangars.
PFAS in Landfills
Landfilling is one of the most common disposal methods for end-of-life consumer products. A variety of consumer products (e.g., textiles, carpets) and packaging (e.g., paper, cardboard) containing PFAS are sent to municipal landfills at the end of their useful lives.
Following disposal, PFAS can be released from the waste through leaching. Leachate from unlined landfills can generate plumes downgradient of the landfill. Leachate collected in lined landfills is typically treated onsite and/or sent to wastewater treatment plants (WWTPs) for treatment. Many municipal WWTPs have been identified as having PFAS in their influent. Recent studies have shown PFAS in WWTP influents to be in the tens to hundreds of nanograms per liter. Conventional sewage treatment methods do not efficiently remove PFAS.