The near ubiquitous presence of perfluoroalkyl acids (PFAAs) in humans has raised concerns about potential human health effects from these chemicals, some of which are both extremely persistent and bioaccumulative. Because some of these chemicals are highly water soluble, one major pathway for human exposure is the consumption of contaminated drinking water. There are no legally enforceable federal standards for PFAAs in drinking water in the U.S., but two PFAAs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are currently listed on U.S. EPA Contaminant Candidate List 3. While the regulatory focus has generally been directed at PFOS and PFOA, the inclusion of other PFAAs in the U.S. EPA Unregulated Contaminant Monitoring Rule 3 indicates that a larger suite of PFAAs may be regulated in the future. This study measured concentrations of PFAAs in 20 drinking water sources and evaluated 15 full-scale treatment systems for the attenuation of PFAAs in water treatment utilities throughout the U.S. A liquid-chromatography tandem mass-spectrometry method was used to enable measurement of a suite of PFAAs, including perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs). Despite the differences in reporting levels, the PFAAs that were detected in >70% of the source water samples (n = 39) included PFSAs, perfluorobutane sulfonic acid (74%), perfluorohexane sulfonic acid (79%), and perfluorooctane sulfonic acid (84%), and PFCAs, perfluoropentanoic acid (74%), perfluorohexanoic acid (79%), perfluoroheptanoic acid (74%), and perfluorooctanoic acid (74%). More importantly, water treatment techniques such as ferric or alum coagulation, granular/micro-/ultrafiltration, aeration, oxidation (i.e., permanganate, ultraviolet/hydrogen peroxide), and disinfection (i.e., ozonation, chlorine dioxide, chlorination, and chloramination) were mostly ineffective in removing PFAAs. However, anion exchange and granular activated carbon treatment preferably removed longer-chain PFAAs and the PFSAs compared to the PFCAs, and reverse osmosis demonstrated significant removal for all the PFAAs, including the smallest PFAA, perfluorobutanoic acid.

Occurrence and control of perfluoroalkyl acids in drinking water systems

248th National Meeting (2014)

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