Trifluoroacetic Acid (TFA) Exceeds All Other Extractable Organofluorine in Drinking Water from Eastern Massachusetts, United States

Per- and polyfluoroalkyl substances (PFAS) are present in drinking water consumed by ~200 million United States (US) residents, but many are not detected by routine monitoring methods. Here, we aimed to better characterize the organofluorine mass budget in US drinking water samples from 19 sites in eastern Massachusetts. Extractable organofluorine (EOF) was detected at 16/17 sites served by community water systems (CWS) using conventional treatment techniques (coagulation, flocculation, clarification, and filtration). At these sites, a suite of 37 targeted PFAS accounted for 6-68% of the extractable organofluorine (EOF) and suspect screening identified fluorinated agrochemicals in almost all samples. High EOF concentrations in untreated source waters for two CWS that used granular activated carbon (GAC) and ion-exchange (IX) treatment, were reduced below detection in finished drinking water samples. Our EOF measurements were not selective for trifluoroacetic acid (TFA), so we measured concentrations in triplicate samples at one conventional treatment site, and from the IX, and GAC sites. At these sites, TFA concentrations were higher than EOF and were unaffected by treatment type. Results of this pilot study show GAC and IX treatment removed virtually all organofluorine in drinking water other than TFA.