Frequently Asked Questions
Q: What are PFAS?
PFAS, also known as “forever chemicals,” are a group of man-made chemicals that includes perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), GenX, ADONA, and many other chemicals. There are thousands of known species of PFAS. PFAS have been manufactured and used in various industries around the globe, including in the United States, since the 1940s. PFOA and PFOS have been the most extensively produced and studied of these chemicals. Both are being phased out of manufacturing in the US at this time.
Q: How does PFAS get into our water supplies?
Aqueous film-forming foam (AFFF), or firefighting foam, has been a major source of PFAS contamination since its use in the late 1960s to extinguish petroleum fires at airfields, oil refineries, and military installations. Other important PFAS sources include the manufacture of consumer and industrial products such as Teflon-coated utensils, carpets, pizza boxes, popcorn bags, chrome plating, pesticides, textiles, semiconductors, and the manufacture of wires and cables. After decades of disposing of PFAS-containing items in landfills, leachate sent to wastewater treatment plants (WWTP) has resulted in additional contamination of WWTP effluents and biosolids that are subsequently used as fertilizer.
Q: What are the current regulations for PFAS in drinking water?
Health advisory levels vary throughout the world. However, in March 2023, the US EPA issued a proposed maximum contaminant level (MCL) of 4 parts per trillion (ppt) for PFOS and PFOA, along with a hazard index for several other PFAS, including PFBS, PFHxS, PFNA, and GenX. Many states in the US have issued health guidelines more stringent than the federal level.
Q: How can PFAS be removed from water?
According to the EPA’s Drinking Water Treatability Database, processes such as granular activated carbon, membrane separation, ion exchange, and powdered activated carbon are standard treatment technologies for drinking water treatment for PFAS removal. Aside from these technologies, PFAS removal is resistant to many, if not most, water treatment processes, while other technologies may increase their concentrations.
Q: What is the history of PFAS?
- PTFE, commercially known as Teflon, was discovered in the 1930s.
- The first applications included non-stick coatings for pans starting in the 1940s.
- PFAS’s natural ability to resist oil and water lent its utility to products like stain and water-resistant products.
- In the 1960s, PFOS was developed to help combat fires for aircraft landing on Navy ships. Aqueous Film Forming Foams (AFFF) use spread to all Department of Defense (DOD) sites and commercial airports for both fire suppression and practice. Many lives have been saved by using AFFF.
- In the 1970s waterproof fabrics hit the market for consumer and military applications.
- Paper coating applications exploded into use for everything from popcorn bags and fast-food wrappers to toilet paper.
- The number of different PFAS chemicals today is estimated to be in the thousands of different species.
Sources:
www.nytimes.com,
www.aps.org,
www.ncbi.nlm.nih.gov,
www.static.ewg.org ,
www.time.com,
www.fda.gov, and
www.nieh.nih.gov
What other names are used to refer to PFAS?
PFAS chemicals, PFCs, and fluorocarbon chemicals, are additional names used for the category of PFAS or its subsets. A listing of the more commonly found PFAS includes:
- Perfluorobutanoic acid (PFBA)
- Perfluoropentanoic acid (PFPeA)
- Perfluorohexanoic acid (PFHxA)
- Perfluoroheptanoic acid (PFHpA)
- Perfluorooctanoic acid (PFOA)
- Perfluorononanoic acid (PFNA)
- Perfluorodecanoic acid (PFDA)
- Perfluoroundecanoic acid (PFUnA)
- Perfluorododecanoic acid (PFDoA)
- Perfluorotridecanoic acid (PFTrDA)
- Perfluorotetradecanoic acid (PFTA)
- Perfluorobutanesulfonic acid (PFBS)
- Perfluorohexanesulfonic acid (PFHxS)
- Perfluorooctanesulfonic acid (PFOS)
- Hexafluoropropylene oxide dimre acid (HFPO-DA) (GenX)
- 4,8-dioxa-3H-perfluorononanoic acid (ADONA)
- N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
- N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA
- 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
- 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
Other common terms used to describe PFAS include “long-chain,” a sulfonic-based PFAS with six or more carbons in the polymer chain (i.e., PFOS and PFHxS), and carboxylic acid-based PFAS with eight or more carbons in their polymer chain (i.e., PFOA and PFNA). “Short-chain” PFAS refers to those compounds having fewer carbons than the “long-chain” definitions used above (i.e., PFBS and PFBA).
