This metadata record contains one table and one shapefile with results from field sampling at locations of groundwater discharge (seeps) identified by autonomous boat survey at the Lower Darby Creek Area (LDCA) Superfund Site, near Folcroft, Pennsylvania, in 2024. Included in the dataset are (1) PFAS concentrations, volatile organic compound (VOC) concentrations, cations/trace metals data, total organic carbon (TOC) content, anion concentrations, dissolved gas concentrations, total and ferrous iron concentrations, sulfide concentrations, water quality measurements, and their associated field sampling information for porewater samples collected from seeps and (2) water quality parameters (pH, turbidity, dissolved oxygen, specific conductance, and water temperature) and coordinates measured in creeks in LDCA by a remote-controlled autonomous boat as part of seep identification surveys.

Per- and polyfluoroalkyl substances (PFAS) and co-occurring inorganic and organic contaminants are widely distributed in the environment and understanding their surface water sources is critical for water resource management. In November 2021, 13 sites were sampled along a stream reach in the Neshaminy Creek basin in southeastern Pennsylvania utilizing a time of travel sampling approach. The reach had known potential PFAS source inputs and documented PFAS detections in water samples. This data release describes the sampling approach, sample processing, laboratory analytical methods, and contains the results. Site (Table1_NC_2021_Site_Info) and constituent information (Table2_Constituents) are provided in tab delimited text (txt) files. Results are provided in a machine readable format in Table3_Reporting_Long.txt for the following hydrologic metrics and chemical constituents: (1) field parameters (instantaneous discharge, water and air temperature, barometric pressure, pH, specific conductance, and dissolved oxygen), (2) optical properties (ultraviolet (UV)-visible absorbance, and fluorescence), (3) dissolved organic carbon and total dissolved nitrogen, (4) major anions, (5) major and trace elements, (6) PFAS, (7) pharmaceutical compounds, and (8) volatile organic compounds. Table_4_Wide_Summary.xlxs is a summary file including the reported values, laboratory standard deviations, remark codes, and qualification codes from Table3_Reporting_Long.txt as eight wide format pivot tables.

Per- and polyfluoroalkyl substances (PFAS) and co-occurring inorganic and organic contaminants are widely distributed in the environment and understanding their surface water sources is critical for water resource management. In November 2021, 13 sites were sampled along a stream reach in the Neshaminy Creek basin in southeastern Pennsylvania utilizing a time of travel sampling approach. The reach had known potential PFAS source inputs and documented PFAS detections in water samples. This data release describes the sampling approach, sample processing, laboratory analytical methods, and contains the results. Site (Table1_NC_2021_Site_Info) and constituent information (Table2_Constituents) are provided in tab delimited text (txt) files. Results are provided in a machine readable format in Table3_Reporting_Long.txt for the following hydrologic metrics and chemical constituents: (1) field parameters (instantaneous discharge, water and air temperature, barometric pressure, pH, specific conductance, and dissolved oxygen), (2) optical properties (ultraviolet (UV)-visible absorbance, and fluorescence), (3) dissolved organic carbon and total dissolved nitrogen, (4) major anions, (5) major and trace elements, (6) PFAS, (7) pharmaceutical compounds, and (8) volatile organic compounds. Table_4_Wide_Summary.xlxs is a summary file including the reported values, laboratory standard deviations, remark codes, and qualification codes from Table3_Reporting_Long.txt as eight wide format pivot tables.

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.

The USGS Pennsylvania Water Science Center (USGS PAWSC) in cooperation with the Pennsylvania Department of Environmental Protection (PADEP) has assembled this data release in support of ongoing USGS and PADEP evaluations related to the occurrence and distribution of Per-and Polyfluorinated Alkyl Substances (PFAS) within Pennsylvania surface water. The data is of four general types: 1. Discrete sample (one moment in time) PFAS concentration data from untreated surface water (raw stream and raw lake water) intended to describe environmental occurrence and distribution of PFAS, not to assess risk in drinking water; 2. Quality-control (QC) PFAS data from samples intended to evaluate the effectiveness and reliability of PFAS data collection from surface water; 3. Passive sampler (time weighted average) PFAS concentration data intended to describe a monthly average of PFAS concentrations at a single site, and finally; 4. Site locations and characteristics for each sampling site within the Pennsylvania Surface Water Quality Network (WQN) information that is presented for future interpretations of this data. Passive water samplers, unlike traditional discrete samples, can be deployed to collect data for several weeks at a time. Polar organic chemical integrative samplers (POCIS) use microporous membranes to sample hydrophilic contaminants. Eighteen POCIS were deployed for approximately one month during August and September 2019 to monitor PFAS. Six quality control samples were also collected with the environmental samples. More information about passive sampling can be found at the USGS Columbia Environmental Research Center website Passive Sampling Using SPMDs and POCIS. The USGS PAWSC has partnered with PADEP to operate the Pennsylvania Surface Water Quality Network (WQN) since 2002. Pennsylvania uses information produced from this partnership to evaluate trends in water quality, collect data to inform current or future permitting, to assess water for the Federal Clean Water Act Sections 303(d) and 305(b), and to evaluate emerging science topics, such as PFAS. This study used adapted-USGS surface-water sampling techniques to provide information on PFAS and PFAS precursor concentrations in surface water. The information presented herein is relevant to the PADEP, other state and federal agencies, local water resource managers, and the public. The outcomes of this data collection are: - A total of 303 samples (discrete, passive, qc) samples were collected and analyzed for this data collection effort. 180 discrete samples were collected at USGS & WQN surface water stations, with 36 QC samples, were analyzed at SGS AXYS Analytical (British Columbia, Canada) for 33 PFAS compounds and 19 PFAS precursor compounds (52 total PFAS-related analytes). 18 sites were concurrently sampled with POCIS passive samplers and 6 QC samples were collected with passive samplers that were analyzed at SGS AXYS Analytical only for the 33 PFAS compounds (not for PFAS precursor compounds). A total of 15 additional samples were analyzed by the PA DEP Bureau of Laboratories for 18 PFAS compounds to compare PFAS concentrations between two analytical methods. Finally, 48 equipment-cleaning QC blanks were collected and analyzed at the USGS National Water Quality Laboratory for 34 PFAS to evaluate cleaning effectiveness for future USGS and PA DEP studies. - Modified USGS stream sampling protocols were determined to be reliable for sampling ng/L (parts per trillion, ppt) levels of PFAS. Insights gained will be used to inform updates the USGS National Field Manual for the Collection of Water Quality Samples. - This first-of-its-kind PFAS dataset will improve understanding of PFAS distribution, to an extent, across the State of Pennsylvania landscape. - Inform future PFAS and ancillary data collection. - Provide PADEP Bureau of Laboratories and the USGS National Water Quality Laboratory with surface water samples to support method validation efforts. - This data will

The USGS Pennsylvania Water Science Center (USGS PAWSC) in cooperation with the Pennsylvania Department of Environmental Protection (PADEP) has assembled this data release in support of ongoing USGS and PADEP evaluations related to the occurrence and distribution of Per-and Polyfluorinated Alkyl Substances (PFAS) within Pennsylvania surface water. The data is of four general types: 1. Discrete sample (one moment in time) PFAS concentration data from untreated surface water (raw stream and raw lake water) intended to describe environmental occurrence and distribution of PFAS, not to assess risk in drinking water; 2. Quality-control (QC) PFAS data from samples intended to evaluate the effectiveness and reliability of PFAS data collection from surface water; 3. Passive sampler (time weighted average) PFAS concentration data intended to describe a monthly average of PFAS concentrations at a single site, and finally; 4. Site locations and characteristics for each sampling site within the Pennsylvania Surface Water Quality Network (WQN) information that is presented for future interpretations of this data. Passive water samplers, unlike traditional discrete samples, can be deployed to collect data for several weeks at a time. Polar organic chemical integrative samplers (POCIS) use microporous membranes to sample hydrophilic contaminants. Eighteen POCIS were deployed for approximately one month during August and September 2019 to monitor PFAS. Six quality control samples were also collected with the environmental samples. More information about passive sampling can be found at the USGS Columbia Environmental Research Center website Passive Sampling Using SPMDs and POCIS. The USGS PAWSC has partnered with PADEP to operate the Pennsylvania Surface Water Quality Network (WQN) since 2002. Pennsylvania uses information produced from this partnership to evaluate trends in water quality, collect data to inform current or future permitting, to assess water for the Federal Clean Water Act Sections 303(d) and 305(b), and to evaluate emerging science topics, such as PFAS. This study used adapted-USGS surface-water sampling techniques to provide information on PFAS and PFAS precursor concentrations in surface water. The information presented herein is relevant to the PADEP, other state and federal agencies, local water resource managers, and the public. The outcomes of this data collection are: - A total of 303 samples (discrete, passive, qc) samples were collected and analyzed for this data collection effort. 180 discrete samples were collected at USGS & WQN surface water stations, with 36 QC samples, were analyzed at SGS AXYS Analytical (British Columbia, Canada) for 33 PFAS compounds and 19 PFAS precursor compounds (52 total PFAS-related analytes). 18 sites were concurrently sampled with POCIS passive samplers and 6 QC samples were collected with passive samplers that were analyzed at SGS AXYS Analytical only for the 33 PFAS compounds (not for PFAS precursor compounds). A total of 15 additional samples were analyzed by the PA DEP Bureau of Laboratories for 18 PFAS compounds to compare PFAS concentrations between two analytical methods. Finally, 48 equipment-cleaning QC blanks were collected and analyzed at the USGS National Water Quality Laboratory for 34 PFAS to evaluate cleaning effectiveness for future USGS and PA DEP studies. - Modified USGS stream sampling protocols were determined to be reliable for sampling ng/L (parts per trillion, ppt) levels of PFAS. Insights gained will be used to inform updates the USGS National Field Manual for the Collection of Water Quality Samples. - This first-of-its-kind PFAS dataset will improve understanding of PFAS distribution, to an extent, across the State of Pennsylvania landscape. - Inform future PFAS and ancillary data collection. - Provide PADEP Bureau of Laboratories and the USGS National Water Quality Laboratory with surface water samples to support method validation efforts. - This data will

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.

The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) analyzed for per-and polyfluoroalkyl substances (PFAS) in groundwater samples collected from domestic and public drinking water supply wells in California. GAMA-PBP is a cooperative program between the U.S. Geological Survey and the California State Water Resources Control Board. This data release contains data for samples collected from May 2019 through December 2022 and includes revisions to earlier data (Kent, 2021) that were either screened or removed after analysis of quality-control data. Please see the quality-control and other descriptions of the data in the processing steps in the xml file. Subsequent updates will include data for samples collected after December 2022. Data are also publicly available for download from Jurgens and others (2018). The dataset consists of 4 tables. Table 1 lists the names and abbreviations of the twenty-eight PFAS constituents analyzed. Table 2 contains information about each site visited, including location and well depth information. Table 3 contains results for each PFAS constituent analyzed and includes quality-control sample results where applicable. Table 4 contains a list of every sample collected at each site and has a summary of all the PFAS detections for each sample. This data release supercedes previous PFAS data release versions reported by Kent (2021). Version 2.0 of the previous data release (Kent, 2021) contained data for samples collected from May 2019 through June 2021. Data from Kent (2021) is available upon request from the authors of this data release. References: Kent, R.H., 2021, Data sets for: Sampling for Per-and Polyfluoralkly Substances (PFAS) by the GAMA Priority Basin Project (GAMA-PBP)(2019-2021) (ver. 2.0, October 2021): U.S. Geological Survey data release, https://doi.org/10.5066/P92IPRJD. Jurgens, B.C., Jasper, M., Nguyen, D.H., and Bennett, G.L., 2018, USGS CA GAMA-PBP Groundwater Quality Results--Assessment and Trends: U.S. Geological Survey website, available at https://doi.org/10.5066/P91WJ2G1.

The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) analyzed for per-and polyfluoroalkyl substances (PFAS) in groundwater samples collected from domestic and public drinking water supply wells in California. GAMA-PBP is a cooperative program between the U.S. Geological Survey and the California State Water Resources Control Board. This data release contains data for samples collected from May 2019 through December 2022 and includes revisions to earlier data (Kent, 2021) that were either screened or removed after analysis of quality-control data. Please see the quality-control and other descriptions of the data in the processing steps in the xml file. Subsequent updates will include data for samples collected after December 2022. Data are also publicly available for download from Jurgens and others (2018). The dataset consists of 4 tables. Table 1 lists the names and abbreviations of the twenty-eight PFAS constituents analyzed. Table 2 contains information about each site visited, including location and well depth information. Table 3 contains results for each PFAS constituent analyzed and includes quality-control sample results where applicable. Table 4 contains a list of every sample collected at each site and has a summary of all the PFAS detections for each sample. This data release supercedes previous PFAS data release versions reported by Kent (2021). Version 2.0 of the previous data release (Kent, 2021) contained data for samples collected from May 2019 through June 2021. Data from Kent (2021) is available upon request from the authors of this data release. References: Kent, R.H., 2021, Data sets for: Sampling for Per-and Polyfluoralkly Substances (PFAS) by the GAMA Priority Basin Project (GAMA-PBP)(2019-2021) (ver. 2.0, October 2021): U.S. Geological Survey data release, https://doi.org/10.5066/P92IPRJD. Jurgens, B.C., Jasper, M., Nguyen, D.H., and Bennett, G.L., 2018, USGS CA GAMA-PBP Groundwater Quality Results--Assessment and Trends: U.S. Geological Survey website, available at https://doi.org/10.5066/P91WJ2G1.