Occurrence of Perfluoroalkyl Carboxylates and Sulfonates in Drinking Water Utilities and Related Waters from the United States

The prevalence and persistence of perfluoroalkyl compounds (PFCs) in environmental and biological systems has been well documented, and a rising number of reports suggest that certain PFCs can result in adverse health effects in mammals. As traditional water sources become increasingly impacted by waste discharge and the demand for planned potable reuse grows, there is recent interest in determining PFC occurrence in drinking water supplies. Here we report monitoring results from drinking water treatment facility samples collected across the United States, and from associated surface, ground, and wastewater sources. Using automated solid phase extraction (SPE) and isotope-dilution liquid chromatography/tandem mass spectrometry (LC/MS-MS), samples were screened for perfluorohexanoic acid (PFHxA), perfluorohexanesulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS), perfluorononanoic acid (PFNA) perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA), and perfluorododecanoic acid (PFDoA). Method reporting limits (MRLs) were established at 1.0 ng/L for all monitored PFCs except PFOA, for which the MRL was set at 5.0 ng/L given elevated procedural and instrumental background levels. PFOS was the only investigated PFC detected in minimally impacted surface waters, with individual site averages of 2.0 ng/L and lower. Conversely, wastewater treatment plant (WWTP) effluents and other highly impacted waters had almost 100% detection frequency for all PFCs except PFUdA and PFDoA, which were not detected above MRL in any samples. Of the investigated PFCs, PFOA averaged the highest overall concentration at any site at 115 ng/L. Substantial impacts from treated wastewater generally caused increased summed PFC concentrations at downstream drinking water facilities, although levels and distribution suggest geographical variability. No discernible differences between influent and effluent PFC levels were observed for drinking water facilities. Removal of PFCs, however, was observed at an indirect potable reuse facility using microfiltration and reverse osmosis for wastewater treatment, in which case all PFC levels in effluents were below the MRL.