Challenges and Research NeedsPFOA and PFOS account for only a small fraction of the total organic fluorine present in water and wastewater samples. Certain polyfluoroalkyl substances, including FTOHs, EtFOSE, and cationic/zwitterionic PFAS, can transform to PFOA and PFOS during chemical, biological, and thermal treatments. However, there are also unidentified precursors present in drinking water (Boiteux et al. 2017). The removal of precursors of PFOA and PFOS is the key to safeguarding drinking-water quality. The source water chemistry, the dose and type of disinfectants, and adequate pretreatments prior to the biological treatment or chemical disinfection are likely the main factors for controlling the formation of PFOA and PFOS in water and wastewater treatment processes.Various advanced technologies have been developed to remove PFOA, PFOS, and their precursor compounds from drinking water. Although some of these treatments have been successful in research labs [see references in Espan et al. (2015)], most of these approaches have major economic or design challenges prior to implementation for treatment of natural waters containing colloidal particles and dissolved organic matter (NOM) at circumneutral pH. At present, GAC adsorption appears to be one of the very few scalable treatment options for PFAS. The author believes that PFOA, PFOS, and their precursor compounds could be controlled by preoxidation via ozone or advanced oxidation processes to transfer precursor compounds to perfluoroalkyl substances (e.g., PFOA and PFOS), followed by adsorption of PFAS by GAC and thermal treatment of PFAS-laden GAC at 700°C or above (Xiao 2019).Conversely, although the thermal treatment holds promise for degradation of PFAS chemicals and reactivation of PFAS-laden GAC (Duchesne et al. 2020; Sasi et al. 2021; Watanabe et al. 2018; Xiao et al. 2020), carbon loss, energy cost, and volatile decomposition products of PFAS are potential concerns. Further studies are suggested to investigate alternative reactivation methods, such as chemical (Huling et al. 2005) or electrochemical (Karimi-Jashni and Narbaitz 2005) approaches, for PFAS-spent GAC.Nanofiltration (NF) and reverse osmosis (RO) as advanced separation technologies are capable of removing PFAS from water (Appleman et al. 2013; Tang et al. 2006), although not every community can afford to include NF and RO in the water treatment system. The main residual produced from an NF or RO system is brine containing elevated levels of NOM and ionic strength. The removal of PFOA, PFOS, or their precursor compounds from NF/RO brine is rarely studied.Furthermore, only limited data are available on the reaction of the cationic and zwitterionic precursor compounds with chemical disinfectants (Xiao et al. 2018). Systematic studies are needed to understand the fate and transformation of cationic and zwitterionic PFAS in water and wastewater treatment processes.Treated water leaving the drinking water treatment plants is usually disinfected and stored prior to distribution. The reaction between precursor compounds and residual chlorine may contribute to a further concentration increase of PFOA and PFOS during water storage. Future studies are suggested to understand the fate and transformation of precursor compounds in storage facilities and distribution systems.References Andrews, D. Q., and O. V. Naidenko. 2020. “Population-wide exposure to per- and polyfluoroalkyl substances from drinking water in the United States.” Environ. Sci. Technol. Lett. 7 (12): 931–936. Appleman, T. D., E. R. Dickenson, C. Bellona, and C. P. Higgins. 2013. “Nanofiltration and granular activated carbon treatment of perfluoroalkyl acids.” J. Hazard. Mater. 260 (Sep): 740–746. Appleman, T. D., C. P. Higgins, O. Quiñones, B. J. Vanderford, C. Kolstad, J. C. Zeigler-Holady, and E. R. Dickenson. 2014. “Treatment of poly- and perfluoroalkyl substances in U.S. full-scale water treatment systems.” Water Res. 51 (Mar): 246–255. Barzen-Hanson, K. A., S. C. Roberts, S. Choyke, K. Oetjen, A. McAlees, N. Riddell, R. McCrindle, P. L. Ferguson, C. P. Higgins, and J. A. Field. 2017. “Discovery of 40 classes of per- and polyfluoroalkyl substances in historical aqueous film-forming foams (AFFFs) and AFFF-impacted groundwater.” Environ. Sci. Technol. 51 (4): 2047–2057. Benskin, J. P., M. G. Ikonomou, F. A. Gobas, T. H. Begley, M. B. Woudneh, and J. R. Cosgrove. 2013. “Biodegradation of N-ethyl perfluorooctane sulfonamido ethanol (EtFOSE) and EtFOSE-based phosphate diester (SAmPAP diester) in marine sediments.” Environ. Sci. Technol. 47 (3): 1381–1389. Blum, A., et al. 2015. “The Madrid statement on poly- and perfluoroalkyl substances (PFASs).” Environ. Health Perspect. 123 (5): A107–A111. Boiteux, V., X. Dauchy, C. Bach, A. Colin, J. Hemard, V. Sagres, C. Rosin, and J. F. Munoz. 2017. “Concentrations and patterns of perfluoroalkyl and polyfluoroalkyl substances in a river and three drinking water treatment plants near and far from a major production source.” Sci. Total Environ. 583 (Apr): 393–400. Boulanger, B., J. D. Vargo, J. L. Schnoor, and K. C. Hornbuckle. 2005. “Evaluation of perfluorooctane surfactants in a wastewater treatment system and in a commercial surface protection product.” Environ. Sci. Technol. 39 (15): 5524–5530. Buck, R. C., J. Franklin, U. Berger, J. M. Conder, I. T. Cousins, P. de Voogt, A. A. Jensen, K. Kannan, S. A. Mabury, and S. P. van Leeuwen. 2011. “Perfluoroalkyl and polyfluoroalkyl substances in the environment: Terminology, classification, and origins.” Integr. Environ. Assess. Manage. 7 (4): 513–541. Clara, M., O. Gans, S. Weiss, D. Sanz-Escribano, S. Scharf, and C. Scheffknecht. 2009. “Perfluorinated alkylated substances in the aquatic environment: An Austrian case study.” Water Res. 43 (18): 4760–4768. Clara, M., C. Scheffknecht, S. Scharf, S. Weiss, and O. Gans. 2008. “Emissions of perfluorinated alkylated substances (PFAS) from point sources—Identification of relevant branches.” Water Sci. Technol. 58 (1): 59–66. D’Agostino, L. A., and S. A. Mabury. 2014. “Identification of novel fluorinated surfactants in aqueous film forming foams and commercial surfactant concentrates.” Environ. Sci. Technol. 48 (1): 121–129. Dasu, K., J. Liu, and L. S. Lee. 2012. “Aerobic soil biodegradation of 8:2 fluorotelomer stearate monoester.” Environ. Sci. Technol. 46 (7): 3831–3836. Dauchy, X., V. Boiteux, C. Rosin, and J. F. Munoz. 2012. “Relationship between industrial discharges and contamination of raw water resources by perfluorinated compounds: Part II: Case study of a fluorotelomer polymer manufacturing plant.” Bull. Environ. Contam. Toxicol. 89 (3): 531–536. D’eon, J. C., and S. A. Mabury. 2011. “Is indirect exposure a significant contributor to the burden of perfluorinated acids observed in humans?” Environ. Sci. Technol. 45 (19): 7974–7984. Dinglasan, M. J., Y. Ye, E. A. Edwards, and S. A. Mabury. 2004. “Fluorotelomer alcohol biodegradation yields poly- and perfluorinated acids.” Environ. Sci. Technol. 38 (10): 2857–2864. Duchesne, A. L., J. K. Brown, D. J. Patch, D. Major, K. P. Weber, and J. I. Gerhard. 2020. “Remediation of PFAS-contaminated soil and granular activated carbon by smoldering combustion.” Environ. Sci. Technol. 54 (19): 12631–12640. Ericson, I., J. L. Domingo, M. Nadal, E. Bigas, X. Llebaria, B. van Bavel, and G. Lindstrom. 2009. “Levels of perfluorinated chemicals in municipal drinking water from Catalonia, Spain: Public health implications.” Arch. Environ. Contam. Toxicol. 57 (4): 631–638. Eschauzier, C., E. Beerendonk, P. Scholte-Veenendaal, and P. de Voogt. 2012. “Impact of treatment processes on the removal of perfluoroalkyl acids from the drinking water production chain.” Environ. Sci. Technol. 46 (3): 1708–1715. Espan, V. A. A., M. Mallavarapu, and R. Naidu. 2015. “Treatment technologies for aqueous perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA): A critical review with an emphasis on field testing.” Environ. Technol. Innovation 4 (Oct): 168–181. Grandjean, P., E. W. Andersen, E. Budtz-Jorgensen, F. Nielsen, K. Molbak, P. Weihe, and C. Heilmann. 2012. “Serum vaccine antibody concentrations in children exposed to perfluorinated compounds.” J. Am. Med. Assoc. 307 (4): 391–397. Guo, R., W. J. Sim, E. S. Lee, J. H. Lee, and J. E. Oh. 2010. “Evaluation of the fate of perfluoroalkyl compounds in wastewater treatment plants.” Water Res. 44 (11): 3476–3486. Hoffman, K., T. F. Webster, S. M. Bartell, M. G. Weisskopf, T. Fletcher, and V. M. Vieira. 2011. “Private drinking water wells as a source of exposure to perfluorooctanoic acid (PFOA) in communities surrounding a fluoropolymer production facility.” Environ. Health Perspect. 119 (1): 92–97. Hoffman, K., T. F. Webster, M. G. Weisskopf, J. Weinberg, and V. M. Vieira. 2010. “Exposure to polyfluoroalkyl chemicals and attention deficit/hyperactivity disorder in U.S. children 12–15 years of age.” Environ. Health Perspect. 118 (12): 1762–1767. Hölzer, J., O. Midasch, K. Rauchfuss, M. Kraft, R. Reupert, J. Angerer, P. Kleeschulte, N. Marschall, and M. Wilhelm. 2008. “Biomonitoring of perfluorinated compounds in children and adults exposed to perfluorooctanoate-contaminated drinking water.” Environ. Health Perspect. 116 (5): 651–657. Houtz, E. F., R. Sutton, J. S. Park, and M. Sedlak. 2016. “Poly- and perfluoroalkyl substances in wastewater: Significance of unknown precursors, manufacturing shifts, and likely AFFF impacts.” Water Res. 95 (May): 142–149. Hu, X. C., et al. 2016. “Detection of poly- and perfluoroalkyl substances (PFASs) in U.S. drinking water linked to industrial sites, military fire training areas, and wastewater treatment plants.” Environ. Sci. Technol. 3 (10): 344–350. Huset, C. A., A. C. Chiaia, D. F. Barofsky, N. Jonkers, H. P. Kohler, C. Ort, D. W. Giger, and J. A. Field. 2008. “Occurrence and mass flows of fluorochemicals in the Glatt valley watershed, Switzerland.” Environ. Sci. Technol. 42 (17): 6369–6377. Ji, K., S. Kim, Y. Kho, D. Paek, J. Sakong, J. Ha, S. Kim, and K. Choi. 2012. “Serum concentrations of major perfluorinated compounds among the general population in Korea: Dietary sources and potential impact on thyroid hormones.” Environ. Int. 45 (Sep): 78–85. Jin, B., S. Mallula, S. A. Golovko, M. Y. Golovko, and F. Xiao. 2020. “In vivo generation of PFOA, PFOS, and other compounds from cationic and zwitterionic per- and polyfluoroalkyl substances in a terrestrial invertebrate (Lumbricus terrestris).” Environ. Sci. Technol. 54 (12): 7378–7387. Joensen, U. N., R. Bossi, H. Leffers, A. A. Jensen, N. E. Skakkebaek, and N. Jorgensen. 2009. “Do perfluoroalkyl compounds impair human semen quality?” Environ. Health Perspect. 117 (6): 923–927. Kim, S., et al. 2011. “Trans-placental transfer of thirteen perfluorinated compounds and relations with fetal thyroid hormones.” Environ. Sci. Technol. 45 (17): 7465–7472. Loganathan, B. G., K. S. Sajwan, E. Sinclair, K. S. Kumar, and K. Kannan. 2007. “Perfluoroalkyl sulfonates and perfluorocarboxylates in two wastewater treatment facilities in Kentucky and Georgia.” Water Res. 41 (20): 4611–4620. Marsh, H., and F. Rodríguez-Reinoso. 2006. Activated carbon. Amsterdam, Netherlands: Elsevier. Martin, J. W., D. A. Ellis, S. A. Mabury, M. D. Hurley, and T. J. Wallington. 2006. “Atmospheric chemistry of perfluoroalkanesulfonamides: Kinetic and product studies of the OH radical and Cl atom initiated oxidation of N-ethyl perfluorobutanesulfonamide.” Environ. Sci. Technol. 40 (3): 864–872. McDonough, C. A., S. Choyke, K. E. Barton, S. Mass, A. P. Starling, J. L. Adgate, and C. P. Higgins. 2021. “Unsaturated PFOS and other PFASs in human serum and drinking water from an AFFF-impacted community.” Environ. Sci. Technol. 55 (12): 8139–8148. McNamara, J. D., R. Franco, R. Mimna, and L. Zappa. 2018. “Comparison of activated carbons for removal of perfluorinated compounds from drinking water.” J. Am. Water Works Assn. 110 (1): E2–E14. Mejia-Avendano, S., S. Vo Duy, S. Sauve, and J. Liu. 2016. “Generation of perfluoroalkyl acids from aerobic biotransformation of quaternary ammonium polyfluoroalkyl surfactants.” Environ. Sci. Technol. 50 (18): 9923–9932. Melzer, D., N. Rice, M. H. Depledge, W. E. Henley, and T. S. Galloway. 2010. “Association between serum perfluorooctanoic acid (PFOA) and thyroid disease in the US national health and nutrition examination survey.” Environ. Health Perspect. 118 (5): 686–692. National Health and Nutrition Examination Survey (NHANES). 2014. Fourth national report on human exposure to environmental chemicals (updated tables). Atlanta, GA: Dept. of Health and Human Services, Centers for Disease Control and Prevention. Nickerson, A., A. E. Rodowa, D. T. Adamson, J. A. Field, P. R. Kulkarni, J. J. Kornuc, and C. P. Higgins. 2021. “Spatial trends of anionic, zwitterionic, and cationic PFASs at an AFFF-impacted site.” Environ. Sci. Technol. 55 (1): 313–323. Paul, A. G., K. C. Jones, and A. J. Sweetman. 2009. “A first global production, emission, and environmental inventory for perfluorooctane sulfonate.” Environ. Sci. Technol. 43 (2): 386–392. Place, B. J., and J. A. Field. 2012. “Identification of novel fluorochemicals in aqueous film-forming foams used by the US military.” Environ. Sci. Technol. 46 (13): 7120–7127. Post, G. B., P. D. Cohn, and K. R. Cooper. 2012. “Perfluorooctanoic acid (PFOA), an emerging drinking water contaminant: A critical review of recent literature.” Environ. Res. 116 (Jul): 93–117. Prevedouros, K., I. T. Cousins, R. C. Buck, and S. H. Korzeniowski. 2006. “Sources, fate and transport of perfluorocarboxylates.” Environ. Sci. Technol. 40 (1): 32–44. Quinones, O., and S. A. Snyder. 2009. “Occurrence of perfluoroalkyl carboxylates and sulfonates in drinking water utilities and related waters from the United States.” Environ. Sci. Technol. 43 (24): 9089–9095. Rahman, M. F., S. Peldszus, and W. B. Anderson. 2014. “Behaviour and fate of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in drinking water treatment: A review.” Water Res. 50 (Mar): 318–340. Rhoads, K. R., E. M. Janssen, R. G. Luthy, and C. S. Criddle. 2008. “Aerobic biotransformation and fate of N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE) in activated sludge.” Environ. Sci. Technol. 42 (8): 2873–2878. Sasi, P. C., A. Alinezhad, B. Yao, A. Kubatova, S. A. Golovko, M. Y. Golovko, and F. Xiao. 2021. “Effect of granular activated carbon and other porous materials on thermal decomposition of per- and polyfluoroalkyl substances: Mechanisms and implications for water purification.” Water Res. 200 (Jul): 117271. Schröder, H. F., and R. J. W. Meesters. 2005. “Stability of fluorinated surfactants in advanced oxidation processes—A follow up of degradation products using flow injection-mass spectrometry, liquid chromatography-mass spectrometry and liquid chromatography-multiple stage mass spectrometry.” J. Chromatogr. A 1082 (1): 110–119. Schultz, M. M., D. F. Barofsky, and J. A. Field. 2006a. “Quantitative determination of fluorinated alkyl substances by large-volume-injection liquid chromatography tandem mass spectrometry—Characterization of municipal wastewaters.” Environ. Sci. Technol. 40 (1): 289–295. Schultz, M. M., C. P. Higgins, C. A. Huset, R. G. Luthy, D. F. Barofsky, and J. A. Field. 2006b. “Fluorochemical mass flows in a municipal wastewater treatment facility.” Environ. Sci. Technol. 40 (23): 7350–7357. Steenland, K., S. Tinker, A. Shankar, and A. Ducatman. 2010. “Association of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) with uric acid among adults with elevated community exposure to PFOA.” Environ. Health Perspect. 118 (2): 229–233. Takagi, S., F. Adachi, K. Miyano, Y. Koizumi, H. Tanaka, M. Mimura, I. Watanabe, S. Tanabe, and K. Kannan. 2008. “Perfluorooctanesulfonate and perfluorooctanoate in raw and treated tap water from Osaka, Japan.” Chemosphere 72 (10): 1409–1412. Takagi, S., F. Adachi, K. Miyano, Y. Koizumi, H. Tanaka, I. Watanabe, S. Tanabe, and K. Kannan. 2011. “Fate of perfluorooctanesulfonate and perfluorooctanoate in drinking water treatment processes.” Water Res. 45 (13): 3925–3932. Tang, C. Y. Y., Q. S. Fu, A. P. Robertson, C. S. Criddle, and J. O. Leckie. 2006. “Use of reverse osmosis membranes to remove perfluorooctane sulfonate (PFOS) from semiconductor wastewater.” Environ. Sci. Technol. 40 (23): 7343–7349. USEPA. 2021. “Announcement of final regulatory determinations for contaminants on the fourth drinking water contaminant candidate list.” Fed. Regist. 86 (40): 12272–12291. Vestergren, R., and I. T. Cousins. 2009. “Tracking the pathways of human exposure to perfluorocarboxylates.” Environ. Sci. Technol. 43 (15): 5565–5575. Vestergren, R., I. T. Cousins, D. Trudel, M. Wormuth, and M. Scheringer. 2008. “Estimating the contribution of precursor compounds in consumer exposure to PFOS and PFOA.” Chemosphere 73 (10): 1617–1624. Wallington, T. J., et al. 2006. “Formation of C7F15COOH (PFOA) and other perfluorocarboxylic acids during the atmospheric oxidation of 8:2 fluorotelomer alcohol.” Environ. Sci. Technol. 40 (3): 924–930. Wang, N., J. Liu, R. C. Buck, S. H. Korzeniowski, B. W. Wolstenholme, P. W. Folsom, and L. M. Sulecki. 2011. “6:2 fluorotelomer sulfonate aerobic biotransformation in activated sludge of waste water treatment plants.” Chemosphere 82 (6): 853–858. Wang, N., B. Szostek, R. C. Buck, P. W. Folsom, L. M. Sulecki, V. Capka, W. R. Berti, and J. T. Gannon. 2005a. “Fluorotelomer alcohol biodegradation-direct evidence that perfluorinated carbon chains breakdown.” Environ. Sci. Technol. 39 (19): 7516–7528. Wang, N., B. Szostek, P. W. Folsom, L. M. Sulecki, V. Capka, R. C. Buck, W. R. Berti, and J. T. Gannon. 2005b. “Aerobic biotransformation of 14C-labeled 8-2 telomer B alcohol by activated sludge from a domestic sewage treatment plant.” Environ. Sci. Technol. 39 (2): 531–538. Wang, Y., G. Arsenault, N. Riddell, R. McCrindle, A. McAlees, and J. W. Martin. 2009. “Perfluorooctane sulfonate (PFOS) precursors can be metabolized enantioselectively: Principle for a new PFOS source tracking tool.” Environ. Sci. Technol. 43 (21): 8283–8289. Wang, Z., J. C. DeWitt, C. P. Higgins, and I. T. Cousins. 2017. “A never-ending story of per- and polyfluoroalkyl substances (PFASs)?” Environ. Sci. Technol. 51 (5): 2508–2518. Watanabe, N., M. Takata, S. Takemine, and K. Yamamoto. 2018. “Thermal mineralization behavior of PFOA, PFHxA, and PFOS during reactivation of granular activated carbon (GAC) in nitrogen atmosphere.” Environ. Sci. Pollut. Res. Int. 25 (8): 7200–7205. Xiao, F. 2019. Fundamentals of adsorption, desorption, and biodegradation of pfas and precursor compounds in the soil and landfill leachate system and an innovative treatment strategy for their removal in landfill leachate and groundwater. Grand Forks, ND: Univ. of North Dakota. Xiao, F., S. A. Golovko, and M. Y. Golovko. 2017. “Identification of novel non-ionic, cationic, zwitterionic, and anionic polyfluoroalkyl substances using UPLC-TOF-MS(E) high-resolution parent ion search.” Anal. Chim. Acta 988 (Oct): 41–49. Xiao, F., T. R. Halbach, M. F. Simcik, and J. S. Gulliver. 2012. “Input characterization of perfluoroalkyl substances in wastewater treatment plants: Source discrimination by exploratory data analysis.” Water Res. 46 (9): 3101–3109. Xiao, F., R. A. Hanson, S. A. Golovko, M. Y. Golovko, and W. A. Arnold. 2018. “PFOA and PFOS are generated from zwitterionic and cationic precursor compounds during water disinfection with chlorine or ozone.” Environ. Sci. Technol. Lett. 5 (6): 382–388. Xiao, F., P. C. Sasi, A. Alinezhad, S. A. Golovko, M. Y. Golovko, and A. Spoto. 2021. “Thermal decomposition of anionic, awitterionic, and cationic polyfluoroalkyl substances in aqueous film-forming foams.” Environ. Sci. Technol. 55 (14): 9885–9894. Xiao, F., P. C. Sasi, B. Yao, A. Kubatova, S. A. Golovko, M. Y. Golovko, and D. Soli. 2020. “Thermal stability and decomposition of perfluoroalkyl substances on spent granular activated carbon.” Environ. Sci. Technol. Lett. 7 (5): 343–350. Xiao, F., M. F. Simcik, and J. S. Gulliver. 2013. “Mechanisms for removal of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) from drinking water by conventional and enhanced coagulation.” Water Res. 47 (1): 49–56. Yeung, L. W., S. Robinson, J. Koschorreck, and S. A. Mabury. 2013. “Part I. A temporal study of PFCAs and their precursors in human plasma from two German cities 1982–2009.” Environ. Sci. Technol. 47 (8): 3865–3874. Yu, J., J. Y. Hu, S. Tanaka, and S. Fujii. 2009. “Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in sewage treatment plants.” Water Res. 43 (9): 2399–2408. Zhao, L., P. K. McCausland, P. W. Folsom, B. W. Wolstenholme, H. Sun, N. Wang, and R. C. Buck. 2013. “6:2 Fluorotelomer alcohol aerobic biotransformation in activated sludge from two domestic wastewater treatment plants.” Chemosphere 92 (4): 464–470. Zhu, B., W. Jiang, W. X. Wang, Y. F. Lin, T. Ruan, and G. B. Jiang. 2019. “Occurrence and degradation potential of fluoroalkylsilane substances as precursors of perfluoroalkyl carboxylic acids.” Environ. Sci. Technol. 53 (9): 4823–4831.

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