A comprehensive, non-targeted analysis of polar organic pollutants using high resolution/accurate mass (HR/AM) mass spectrometry approaches has been applied to water samples from San Francisco (SF) Bay, a major urban...

Per-and polyfluoroalkyl ether acids (PFEAs) are a subclass of per-and polyfluoroalkyl substances (PFAS) that are detected with increasing frequency in environmental matrices. Diet can be an important route of PFEA exposure, but the presence of PFEAs in food is poorly understood. Extraction methods for food samples exist for traditionally studied PFAS, but their suitability for PFEAs and other novel PFAS remains unknown. In this study, an extraction and matrix cleanup method was developed to quantify 45 PFAS, including 13 PFEAs, 3 perfluoroalkane sulfonamides, and 6 fluorotelomer carboxylic acids in 10 types of fruits and vegetables. Homogenized samples were extracted with basic methanol, and resulting extracts were diluted with water and cleaned up using solid-phase extraction with weak anion-exchange cartridges. The method was validated by performing spike−recovery experiments at spike levels of 1 ng/g in all 10 matrices and 0.1 ng/g in 2 matrices. For PFAS without a corresponding isotopically labeled internal standard (IS), adopting an IS with a similar chromatographic retention time generated the most accurate recoveries. Dependent upon the matrix, recoveries of 38−44 PFAS (including 10−13 PFEAs) fell within 50−150% for samples spiked at 1 ng/g. Recoveries of 40 and 38 PFAS in blueberries and corn, respectively, fell within 50−150% for samples spiked at 0.1 ng/g. Method quantification limits (MQLs) of PFAS in pure solvents were determined as the lowest calibration level with an accuracy between 70 and 130%. To compensate for matrix effects, a matrix factor was applied on the basis of the analyte response in different matrices relative to the pure solvent. The MQLs of 45 PFAS (including 13 PFEAs) in 10 matrices ranged from 0.025 to 0.25 ng/g. Overall, this method is capable of sensitively quantifying 45 PFAS in many fruits and vegetables.

Eighteen private well users in North Carolina were recruited to test the performance of under-sink, activated carbon block water filters to remove per-and polyfluoroalkyl substances (PFAS). Monthly sampling was conducted for 8 months. Filters were certified for removal of perfluorooctanoic acid and perfluorooctanesulfonic acid under NSF International certification P473, but not for additional short-chain perfluoroalkyl acids or perfluoroalkyl ether acids (PFEAs) evaluated in this study. Out of 47 targeted analytes, 17 PFAS were detected in filter influent samples (influent P PFAS 4.7-131 ng/L). Mixed-effects Tobit regression models showed that the filters effectively removed 97%-99% of all influent PFAS, including short-chain PFEAs, for the entire manufacturer-recommended lifetime of the device. The prevalence of PFAS above the minimum reporting limits was reduced by 99.5%, and the prevalence of any PFAS above the method detection limits was reduced by 92%. The results provide increased confidence in NSF P473-certified filters for the removal of PFAS from private well water.activated carbon, PFAS, point-of-use water treatment, private wells | INTRODUCTIONPer-and polyfluoroalkyl substances (PFAS)-including perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs) (together referred to as perfluoroalkyl acids (PFAAs)), and replacement perfluoroalkyl ether acids (PFEAs)-have generated concern in recent decades for their widespread environmental