Samples for per- and polyfluoroalkyl substances (PFAS) were collected from 10 domestic wells to assess the extent to which PFAS is coming from the groundwater aquifer or from another source within the home. Specific objectives included: 1. Collect well construction information; 2. Collect samples for analysis of PFAS directly from the aquifer at domestic wells; 3. Collect samples for analysis of PFAS from two locations within the home to compare with samples collected directly from the aquifer; 4. Quality Assure all data in accordance with USGS policies; and 5. Release data to the public as a citable USGS Data Release. Description of Available Datasets: These data are available in Excel (.xlsx) files that contain water-quality and quality-assurance results. The Excel files are duplicated as tab-delimited text files to increase accessibility to nonproprietary formats. The files titled VDH_PFAS_Results contain analytical results and field measurements for samples collected from 10 locations in Virginia. The files titled VDH_PFAS_Quality_Assurance contain associated equipment blanks, field blanks, lab blanks, and replicates used for quality control. Lab blanks are used to assess contamination imparted by the analytical process. Equipment blanks were used to assess possible contamination from sampling equipment. Field blanks were collected using certified analyte-free water at each environmental sample and used to assess possible cross contamination from sampling materials and sampling technique in the field. Field replicates were collected concurrently with the environmental sample and used to understand the variability of results. The attached XML file titled VDH_PFAS_Metadata contains metadata explaining the provenance of the data and should be thoroughly read to understand data structure and limitations. The files titled VDH_PFAS_Data_Dictionary may be used as a reference to explain codes, terms, and abbreviations used in these datasets. The files titled VDH_PFAS_Ongoing_Precision_and_Recovery contain quality assurance samples reported by the laboratory which establishes additional confidence in results over time. Sample Collection, Data Validation, and Quality Assurance: Ten homes were sampled as part of this project and at each location domestic wells were the main source of water. At each home, one sample was collected directly from the aquifer by accessing the well and using pre-cleaned, PFAS-free sampling equipment. Field measurements (pH, specific conductance, temperature, dissolved oxygen, turbidity) were collected in a flow-through cell and recorded with the well sample, before contact with in-house plumbing and before treatment. One sample was collected at the main point of use within the home (typically the kitchen faucet). One sample was collected at an intermediate location within the homes plumbing system located between the well and kitchen faucet. Analyte concentrations were compared between sampling locations within the homes plumbing system to assess the contribution of PFAS from the aquifer and understand possible contribution of PFAS from the homes pluming system. U.S. Environmental Protection Agency (EPA) Method 533 (Rosenblum and Wendelken, 2019) was used to determine PFAS concentrations in all samples. Samples were analyzed at SGS Wilmington in North Carolina. Reporting and detection levels for PFAS results are specific to the analyte, sample matrix, instrumentation, and laboratory performance. Results throughout this dataset that are reported with a less than qualifier represent values that were not detected above the reporting level for that sample and specific analyte. The reporting levels shown in this dataset are synonymous with the minimum reporting level as defined by Rosenblum and Wendelken (2019). A combination of field blanks, laboratory method blanks, carbon-13 labelled internal standard compound recoveries, and ongoing precision and recovery samples were used to assess field techniques and

Concentrations of inorganic constituents, dissolved organic carbon (DOC), tritium, per- and polyfluoroalkyl substances (PFAS), volatile organic compounds (VOCs), and pharmaceuticals were measured in groundwater samples collected from 254 wells in 2019 and 2020. Concentrations of inorganic constituents, DOC, VOCs, and pharmaceuticals were measured at the U.S. Geological Survey (USGS) National Water Quality Laboratory in Lakewood, Colorado. Concentrations of tritium were measured at the USGS Tritium Laboratory in Menlo Park, California. Concentrations of PFAS were measured at SGS Laboratory in Orlando, Florida. In addition, several geospatial parameters were determined, including: percentages of selected land uses within 500-meter buffers around sampled wells, nitrogen loading from septic systems within 500-meter buffers around sampled wells, distance to nearest wastewater treatment plant, and distance to selected industry and other potential point sources that could be sources of PFAS to the environment. The data were collected as part of the USGS National Water-Quality (NAWQA) project. This data release contains 12 tables of well information, laboratory results, geospatial output, and a data dictionary, including: 1) PFAS_Data_Dictionary.csv – Parameters in each table are defined in this table. 2) PFAS_BLANK.csv – Concentrations of PFAS in equipment, field, and source-solution blank samples. 3) PFAS_ENV.csv – Concentrations of PFAS in environmental samples. 4) PFAS_GEOSPATIAL.csv – Percentages of selected land uses within 500-meter buffers around sampled wells; nitrogen loading from septic systems within 500-meter buffers around sampled wells; distance to nearest wastewater treatment plant; distance to selected industry and other potential point sources that could be sources of PFAS to the environment. 5) PFAS_INORGANICS_AND_OTHER.csv – Concentration of inorganic constituents, DOC, and tritium. 6) PFAS_LAB_BLANK.csv – Concentrations of PFAS in laboratory blank samples. 7) PFAS_PHARMA.csv – Concentrations of pharmaceutical compounds in environmental samples. 8) PFAS_REP.csv – Concentrations of PFAS in replicate samples. 9) PFAS_SPIKE_FIELD.csv – Percent recovery for PFAS in field matrix-spike samples. 10) PFAS_SPIKE_LAB.csv – Percent recovery for PFAS in laboratory reagent-spike and matrix-spike samples. 11) PFAS_VOCs.csv – Concentrations of VOCs in environmental samples. 12) PFAS_WELLS.csv – Site characteristics of the sampled wells.

Concentrations of inorganic constituents, dissolved organic carbon (DOC), tritium, per- and polyfluoroalkyl substances (PFAS), volatile organic compounds (VOCs), and pharmaceuticals were measured in groundwater samples collected from 254 wells in 2019 and 2020. Concentrations of inorganic constituents, DOC, VOCs, and pharmaceuticals were measured at the U.S. Geological Survey (USGS) National Water Quality Laboratory in Lakewood, Colorado. Concentrations of tritium were measured at the USGS Tritium Laboratory in Menlo Park, California. Concentrations of PFAS were measured at SGS Laboratory in Orlando, Florida. In addition, several geospatial parameters were determined, including: percentages of selected land uses within 500-meter buffers around sampled wells, nitrogen loading from septic systems within 500-meter buffers around sampled wells, distance to nearest wastewater treatment plant, and distance to selected industry and other potential point sources that could be sources of PFAS to the environment. The data were collected as part of the USGS National Water-Quality (NAWQA) project. This data release contains 12 tables of well information, laboratory results, geospatial output, and a data dictionary, including: 1) PFAS_Data_Dictionary.csv – Parameters in each table are defined in this table. 2) PFAS_BLANK.csv – Concentrations of PFAS in equipment, field, and source-solution blank samples. 3) PFAS_ENV.csv – Concentrations of PFAS in environmental samples. 4) PFAS_GEOSPATIAL.csv – Percentages of selected land uses within 500-meter buffers around sampled wells; nitrogen loading from septic systems within 500-meter buffers around sampled wells; distance to nearest wastewater treatment plant; distance to selected industry and other potential point sources that could be sources of PFAS to the environment. 5) PFAS_INORGANICS_AND_OTHER.csv – Concentration of inorganic constituents, DOC, and tritium. 6) PFAS_LAB_BLANK.csv – Concentrations of PFAS in laboratory blank samples. 7) PFAS_PHARMA.csv – Concentrations of pharmaceutical compounds in environmental samples. 8) PFAS_REP.csv – Concentrations of PFAS in replicate samples. 9) PFAS_SPIKE_FIELD.csv – Percent recovery for PFAS in field matrix-spike samples. 10) PFAS_SPIKE_LAB.csv – Percent recovery for PFAS in laboratory reagent-spike and matrix-spike samples. 11) PFAS_VOCs.csv – Concentrations of VOCs in environmental samples. 12) PFAS_WELLS.csv – Site characteristics of the sampled wells.

This data release provides concentration results for per- and polyfluoroalkyl substances (PFAS) collected by volunteer community members, in tapwater samples from 84 private residences, in select areas within the United States. Samples were collected July 1, 2023, through October 3, 2024. Samples were analyzed at the U.S. Geological Survey National Water Quality Laboratory (NWQL) in Denver, Colorado. Exact site location information for these sites is not available because of privacy concerns.

This data release provides concentration results for per- and polyfluoroalkyl substances (PFAS) collected by volunteer community members, in tapwater samples from 83 private residences, in select areas within the United States. Samples were collected July 1, 2023, through November 10, 2023. Samples were analyzed at the U.S. Geological Survey National Water Quality Laboratory (NWQL) in Denver, Colorado. Exact site location information for these sites is not available because of privacy concerns.

Per- and polyfluoroalkyl substances (PFAS) and related chemical and physical data are presented from shallow soil and groundwater at two sites in New Hampshire. The two sites, the former Brentwood Fire Training Area and White Farm, were selected because materials known to contain PFAS were used at each site. White Farm is an active farm where biosolids have been applied for several years. At the former Brentwood Fire Training Area, PFAS-containing aqueous film-forming foams were applied as part of regular fire training exercises. At each site, soil samples were collected in a gridded pattern over the site. Soil horizons within the sampling intervals were described using the National Soil Survey Center Natural Resources Conservation Service U.S. Department of Agriculture Field Book for Describing and Sampling Soils (Schoeneberger and others, 2012). Analyses included 36 PFAS compounds, 36 PFAS compounds post-total oxidizable precursor assay (TOPA), total organic carbon (TOC), moisture content, pH, autoclaved-citrate extractable protein, grain size, major ions and other physical and physicochemical parameters. Groundwater samples were collected and analyzed for PFAS during two sampling events at each site from temporary wells, existing monitoring wells, and/or pushpoint samplers. Additionally, a lysimeter was installed at the center of each site and a composite sample through the duration of each water sampling event (approximately 7 days) was collected. Quality control samples included source-solution blanks, equipment blanks, and replicates. Reference: Schoeneberger, P.J., Wysocki, D.A., Benham, E.C., and Soil Survey Staff, 2012, Field book for describing and sampling soils, Version 3.0: Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE.

Per- and polyfluoroalkyl substances (PFAS) and related chemical and physical data are presented from shallow soil and groundwater at two sites in New Hampshire. The two sites, the former Brentwood Fire Training Area and White Farm, were selected because materials known to contain PFAS were used at each site. White Farm is an active farm where biosolids have been applied for several years. At the former Brentwood Fire Training Area, PFAS-containing aqueous film-forming foams were applied as part of regular fire training exercises. At each site, soil samples were collected in a gridded pattern over the site. Soil horizons within the sampling intervals were described using the National Soil Survey Center Natural Resources Conservation Service U.S. Department of Agriculture Field Book for Describing and Sampling Soils (Schoeneberger and others, 2012). Analyses included 36 PFAS compounds, 36 PFAS compounds post-total oxidizable precursor assay (TOPA), total organic carbon (TOC), moisture content, pH, autoclaved-citrate extractable protein, grain size, major ions and other physical and physicochemical parameters. Groundwater samples were collected and analyzed for PFAS during two sampling events at each site from temporary wells, existing monitoring wells, and/or pushpoint samplers. Additionally, a lysimeter was installed at the center of each site and a composite sample through the duration of each water sampling event (approximately 7 days) was collected. Quality control samples included source-solution blanks, equipment blanks, and replicates. Reference: Schoeneberger, P.J., Wysocki, D.A., Benham, E.C., and Soil Survey Staff, 2012, Field book for describing and sampling soils, Version 3.0: Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE.

Samples were collected for a comparison method development study with the University of Minnesota and the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) in Lakewood, Colorado. Widely used liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods fail to capture large fractions of total organofluorine in environmental samples confounding the assessment and remediation of fluorinated pollution. Fluorine nuclear magnetic resonance (19F-NMR) is an inclusive method for organofluorine analysis that preserves chemical information about chemical compound classes of organofluorine.

These data were collected to understand the occurrence of per- and polyfluoroalkyl substances (PFAS) in drinking water samples at selected public water systems in West Virginia identified to have detections for PFAS above laboratory reporting levels in previously collected raw-water samples (McAdoo and others, 2022). These data are stored in the USGS National Water Information System (NWIS) but are not available to the public from that platform because West Virginia State Law §22-26-4, and USGS policy concerning the release of sensitive water related information, prohibits the release of public water system infrastructure location information. This USGS data release serves as the public release of available data for this project and provides a reference location for all users. Description of Available Datasets: These data are available in Excel (.xlsx) files that contain water-quality and quality-assurance results. The Excel files are duplicated as tab-delimited text files to increase accessibility to nonproprietary formats. The files titled WVDEP_PFAS_FinishedWater_Results contain analytical results for PFAS in drinking water collected at 107 sites located in West Virginia. The files titled WVDEP_PFAS_FinishedWater_Quality_Assurance contain associated field blanks, lab blanks, and replicates used for quality control. Lab blanks are used to assess contamination imparted by the analytical process. Field blanks were collected using certified analyte-free water at the sampling point and used to assess possible cross contamination from sampling materials and sampling technique in the field. Field replicates were collected concurrently with the environmental sample and used to understand the variability of results. The attached XML file titled WVDEP_PFAS_FinishedWater_Metadata contains metadata explaining the provenance of the data and should be thoroughly read to understand data structure and limitations. The files titled WVDEP_PFAS_FinishedWater_Data_Dictionary may be used as a reference to explain codes, terms, and abbreviations used in these datasets. The files titled WVDEP_PFAS_Ongoing_Precision_and_Recovery contain quality assurance samples reported by the laboratory which establishes additional confidence in results over time. Sample Collection, Data Validation, and Quality Assurance: Samples were collected at each public water system’s main finished-water sampling point. U.S. Environmental Protection Agency (EPA) Method 533 (Rosenblum and Wendelken, 2019) and EPA Method 537.1 (Shoemaker, 2020) were used to determine PFAS concentrations in all samples. Samples were analyzed at SGS Wilmington in North Carolina. Reporting and detection levels for PFAS results are specific to the analyte, sample matrix, instrumentation, and laboratory performance. Results throughout this dataset that are reported with a "less than" qualifier represent values that were not detected above the reporting level for that sample and specific analyte. The reporting levels shown in this dataset are synonymous with the minimum reporting level as defined by Rosenblum and Wendelken (2019). A combination of field blanks, laboratory method blanks, isotopically labeled compound recoveries, and ongoing precision and recovery samples were used to assess field techniques and validity of the reported results. Finished water results recorded in the file titled WV_PFAS_Finished_Water_Results met all quality assurance criteria, and no additional qualification was required. References: McAdoo, M.A., Connock, G.T., and Messinger, T., 2022, Occurrence of per- and polyfluoroalkyl substances and inorganic analytes in groundwater and surface water used as sources for public water supply in West Virginia: U.S. Geological Survey Scientific Investigations Report 2022–5067, 37 p., https://doi.org/10.3133/sir20225067. Rosenblum, L., and Wendelken, S.C., 2019, Method 533, Determination of per- and polyfluoroalkyl substances in drinking water by isotope dilution anion exchange

These data were collected to understand the occurrence of per- and polyfluoroalkyl substances (PFAS) in drinking water samples at selected public water systems in West Virginia identified to have detections for PFAS above laboratory reporting levels in previously collected raw-water samples (McAdoo and others, 2022). These data are stored in the USGS National Water Information System (NWIS) but are not available to the public from that platform because West Virginia State Law §22-26-4, and USGS policy concerning the release of sensitive water related information, prohibits the release of public water system infrastructure location information. This USGS data release serves as the public release of available data for this project and provides a reference location for all users. Description of Available Datasets: These data are available in Excel (.xlsx) files that contain water-quality and quality-assurance results. The Excel files are duplicated as tab-delimited text files to increase accessibility to nonproprietary formats. The files titled WVDEP_PFAS_FinishedWater_Results contain analytical results for PFAS in drinking water collected at 107 sites located in West Virginia. The files titled WVDEP_PFAS_FinishedWater_Quality_Assurance contain associated field blanks, lab blanks, and replicates used for quality control. Lab blanks are used to assess contamination imparted by the analytical process. Field blanks were collected using certified analyte-free water at the sampling point and used to assess possible cross contamination from sampling materials and sampling technique in the field. Field replicates were collected concurrently with the environmental sample and used to understand the variability of results. The attached XML file titled WVDEP_PFAS_FinishedWater_Metadata contains metadata explaining the provenance of the data and should be thoroughly read to understand data structure and limitations. The files titled WVDEP_PFAS_FinishedWater_Data_Dictionary may be used as a reference to explain codes, terms, and abbreviations used in these datasets. The files titled WVDEP_PFAS_Ongoing_Precision_and_Recovery contain quality assurance samples reported by the laboratory which establishes additional confidence in results over time. Sample Collection, Data Validation, and Quality Assurance: Samples were collected at each public water system’s main finished-water sampling point. U.S. Environmental Protection Agency (EPA) Method 533 (Rosenblum and Wendelken, 2019) and EPA Method 537.1 (Shoemaker, 2020) were used to determine PFAS concentrations in all samples. Samples were analyzed at SGS Wilmington in North Carolina. Reporting and detection levels for PFAS results are specific to the analyte, sample matrix, instrumentation, and laboratory performance. Results throughout this dataset that are reported with a "less than" qualifier represent values that were not detected above the reporting level for that sample and specific analyte. The reporting levels shown in this dataset are synonymous with the minimum reporting level as defined by Rosenblum and Wendelken (2019). A combination of field blanks, laboratory method blanks, isotopically labeled compound recoveries, and ongoing precision and recovery samples were used to assess field techniques and validity of the reported results. Finished water results recorded in the file titled WV_PFAS_Finished_Water_Results met all quality assurance criteria, and no additional qualification was required. References: McAdoo, M.A., Connock, G.T., and Messinger, T., 2022, Occurrence of per- and polyfluoroalkyl substances and inorganic analytes in groundwater and surface water used as sources for public water supply in West Virginia: U.S. Geological Survey Scientific Investigations Report 2022–5067, 37 p., https://doi.org/10.3133/sir20225067. Rosenblum, L., and Wendelken, S.C., 2019, Method 533, Determination of per- and polyfluoroalkyl substances in drinking water by isotope dilution anion exchange