This dataset contains measurements of dissolved hydrocarbons in from various water sources, as well as ancillary raw calibration data showing the stability of the gas chromatograph with an atomic emission detector and flame ionization detector (GC-AED-FID) analytical system over time. Across multiple studies, samples from tap water, groundwater, surface water, springs, mine outflows, and blank materials were analyzed using this system over a period from 2014 to 2017, comprising 172 samples analyzed. In addition to water samples, 183 calibrations conducted over the same period of time are included to document the stability of the GC-AED-FID system over time. The target analytes in this study were: methane (CH4), ethane (C2H6), ethene (C2H4), ethyne (C2H2), propane (C3H8), propene (C3H6), i-butane (C4H10), n-butane (C4H10), 1-butene (C4H8), propyne (C3H4), i-pentane (C5H12), n-pentane (C5H12), 2-methyl-pentane (C6H14), 3-methyl-pentane (C6H14), hexane (C6H14), and benzene (C6H6).

This dataset contains measurements of dissolved hydrocarbons in from groundwater samples collected in the shale gas producing regions of West Virginia, USA, between June and August of 2018. The target analytes in this study were: methane (CH4), ethane (C2H6), ethene (C2H4), ethyne (C2H2), propane (C3H8), propene (C3H6), i-butane (C4H10), n-butane (C4H10), 1-butene (C4H8), propyne (C3H4), i-pentane (C5H12), n-pentane (C5H12), 2-methyl-pentane (C6H14), 3-methyl-pentane (C6H14), hexane (C6H14), and benzene (C6H6). This dataset also contains corresponding measurements of chlorofluorocarbons (CFCs), Sulfurhexafluoride (SF6), dissolved permanent gases (N2/Ar), tritium, the isotope ratio of helium dissolved in water, the concentration of neon dissolved in water, the isotope ratios of hydrogen-2 and oxygen-18 in water, and the isotope ratio of carbon-13 in dissolved inorganic carbon (DIC).

This dataset contains measurements of dissolved hydrocarbons in from groundwater samples collected in the shale gas producing regions of West Virginia, USA, between June and August of 2018. The target analytes in this study were: methane (CH4), ethane (C2H6), ethene (C2H4), ethyne (C2H2), propane (C3H8), propene (C3H6), i-butane (C4H10), n-butane (C4H10), 1-butene (C4H8), propyne (C3H4), i-pentane (C5H12), n-pentane (C5H12), 2-methyl-pentane (C6H14), 3-methyl-pentane (C6H14), hexane (C6H14), and benzene (C6H6). This dataset also contains corresponding measurements of chlorofluorocarbons (CFCs), Sulfurhexafluoride (SF6), dissolved permanent gases (N2/Ar), tritium, the isotope ratio of helium dissolved in water, the concentration of neon dissolved in water, the isotope ratios of hydrogen-2 and oxygen-18 in water, and the isotope ratio of carbon-13 in dissolved inorganic carbon (DIC).

Water samples from 50 domestic wells located <1 kilometer (km) (proximal) and >1 km (distal) from shale-gas wells in upland areas of the Marcellus Shale region were analyzed for chemical, isotopic and groundwater-age tracers. Uplands were targeted because natural mixing with brine and hydrocarbons from deep formations is less common in those areas compared to valleys. Methane (CH4) -isotope and pre-drill CH4 data indicate one proximal sample (5 percent of proximal samples) contains thermogenic CH4 (2.6 milligrams per liter (mg/L)) associated with shale-gas production. Chloride (Cl), bromide (Br), lithium (Li), and neon-20 (20Ne)/argon-36 (36Ar) data suggest that CH4 leaked from a nearby gas well in a gas phase. Another proximal sample contains volatile hydrocarbons (0.03-0.4 micrograms per liter (µg/L)), including benzene, found in some hydraulic fracturing fluid. Modeled groundwater-age distributions, calibrated to tritium (3H), sulfur hexafluoride (SF6), and carbon-14 (14C) concentrations, indicate that water recharged prior to shale-gas development, suggesting surface releases associated with shale-gas production were not the source of those hydrocarbons, although leakage from a nearby gas well directly into the old groundwater cannot be ruled out. Estimated age distributions in the samples span ~20 to >10,000 years and have implications for relating occurrences of hydrocarbons in groundwater to surface releases associated with recent shale-gas production, and to the time required to flush contaminants from the system. This data release contains isotopic tracer, noble gas, and groundwater-age tracer concentration data collected by the U.S. Geological Survey and data for pH, specific conductance, major ions, and methane collected by Chesapeake Energy Corporation.

Water samples from 50 domestic wells located <1 kilometer (km) (proximal) and >1 km (distal) from shale-gas wells in upland areas of the Marcellus Shale region were analyzed for chemical, isotopic and groundwater-age tracers. Uplands were targeted because natural mixing with brine and hydrocarbons from deep formations is less common in those areas compared to valleys. Methane (CH4) -isotope and pre-drill CH4 data indicate one proximal sample (5 percent of proximal samples) contains thermogenic CH4 (2.6 milligrams per liter (mg/L)) associated with shale-gas production. Chloride (Cl), bromide (Br), lithium (Li), and neon-20 (20Ne)/argon-36 (36Ar) data suggest that CH4 leaked from a nearby gas well in a gas phase. Another proximal sample contains volatile hydrocarbons (0.03-0.4 micrograms per liter (µg/L)), including benzene, found in some hydraulic fracturing fluid. Modeled groundwater-age distributions, calibrated to tritium (3H), sulfur hexafluoride (SF6), and carbon-14 (14C) concentrations, indicate that water recharged prior to shale-gas development, suggesting surface releases associated with shale-gas production were not the source of those hydrocarbons, although leakage from a nearby gas well directly into the old groundwater cannot be ruled out. Estimated age distributions in the samples span ~20 to >10,000 years and have implications for relating occurrences of hydrocarbons in groundwater to surface releases associated with recent shale-gas production, and to the time required to flush contaminants from the system. This data release contains isotopic tracer, noble gas, and groundwater-age tracer concentration data collected by the U.S. Geological Survey and data for pH, specific conductance, major ions, and methane collected by Chesapeake Energy Corporation.

Historical water and gas chemistry data from geothermal areas are important for detecting long-term patterns, informing geothermal energy exploration, development, and use, and for contextualizing more recent data. The U.S. Geological Survey has published water and gas chemistry data from geothermal areas in the western United States, which is primarily available as scanned PDF files. This makes the data difficult to access or include in large-scale data analysis. This data release provides digitized and reformatted data from 20 previously published U.S. Geological Survey Open-File reports and journal articles, representing 1867 water chemistry samples and 313 gas chemistry samples. All data have been standardized to the same units, geographic coordinates, and file format. Description of sample site location was improved. Many reports do not report geographic location coordinates; those that do are frequently inaccurate, as latitude and longitude were interpolated from a map, or in some cases, estimated in the field before the common use of global positioning systems (GPS). Collection dates for individual samples range from 1930 to 2005, although most samples were collected between the years 1970 and 2000. Samples are primarily from California, Oregon, and Washington, although some reports include data from sites in Montana, Idaho, Nevada, Utah, Arizona, and New Mexico. Attributes for both water and gas chemistry are: Sample name, Sample ID, Type, Collection date, Collection time, Reported location, Reported latitude, Reported longitude, Reported Easting, Reported Northing, Location description, Region, State, County, Latitude, Longitude, Location resolution, Location error, Elevation, Source, Author comment, and Digitizer comment. Attributes for water chemistry are: Well depth, Collection depth, Discharge, Temperature, pH (field), pH (lab), pH, Aluminum (Al), Arsenic (As), Boron (B), Barium (Ba), Bromide (Br), Calcium (Ca), Chloride (Cl), Carbonate (CO3), Alkalinity as carbonate (CO3), Cesium (Cs), Copper (Cu), Dissolved Organic Carbon as Carbon (DIC as C), Fluoride (F), Iron (Fe), Hydrogen sulfide (H2S), Bicarbonate (HCO3), Alkalinity as bicarbonate (HCO3), Carbonic acid (H2CO3), Mercury (Hg), Iodide (I), Potassium (K), Lithium (Li), Magnesium (Mg), Manganese (Mn), Molybdenum (Mo), total Nitrogen (N), Sodium (Na), Ammonium (NH4), Nickel (Ni), Nitrate (NO3), total Phosphorus (P), Lead (Pb), Phosphate (PO4), Rubidium (Rb), Silica (SiO2), Sulfate (SO4), Strontium (Sr), Uranium (U), Vanadium (V), Zinc (Zn), Reported cations, Reported anions, Cations, Anions, Reported total dissolved solids, Salinity, Charge balance, Specific conductance, isotopic composition of hydrogen (Delta 2H), isotopic composition of oxygen in water (Delta 18O (H2O)), Oxygen shift, isotopic composition of oxygen in sulfate (Delta 18O (SO4)), isotopic composition of carbon (Delta 13C), isotopic composition of carbon in dissolved inorganic carbon (Delta 13C (DIC)), Tritium (3H), and 14C. Attributes for gas chemistry are: Temperature, Total gas, argon (Ar), oxygen and argon (O2 + Ar), ethane (C2H6), methane (CH4), carbon dioxide (CO2), hydrogen (H2), hydrogen sulfide (H2S), helium (He), nitrogen (N2), ammonia (NH3), oxygen (O2), dissolved argon (Ar dissolved), dissolved methane (CH4 dissolved), dissolved carbon dioxide (CO2 dissolved), dissolved hydrogen (H2 dissolved), dissolved helium (He dissolved), dissolved nitrogen (N2 dissolved), dissolved ammonia (NH3 dissolved), dissolved oxygen (O2 dissolved), isotopic ratio of helium (3He/4He), isotopic ratio of helium corrected for the atmospheric isotopic composition of helium (3He/4He corrected), isotopic composition of nitrogen (Delta 15N), and isotopic composition of carbon in carbon dioxide (Delta 13C (CO2)).

Historical water and gas chemistry data from geothermal areas are important for detecting long-term patterns, informing geothermal energy exploration, development, and use, and for contextualizing more recent data. The U.S. Geological Survey has published water and gas chemistry data from geothermal areas in the western United States, which is primarily available as scanned PDF files. This makes the data difficult to access or include in large-scale data analysis. This data release provides digitized and reformatted data from 20 previously published U.S. Geological Survey Open-File reports and journal articles, representing 1867 water chemistry samples and 313 gas chemistry samples. All data have been standardized to the same units, geographic coordinates, and file format. Description of sample site location was improved. Many reports do not report geographic location coordinates; those that do are frequently inaccurate, as latitude and longitude were interpolated from a map, or in some cases, estimated in the field before the common use of global positioning systems (GPS). Collection dates for individual samples range from 1930 to 2005, although most samples were collected between the years 1970 and 2000. Samples are primarily from California, Oregon, and Washington, although some reports include data from sites in Montana, Idaho, Nevada, Utah, Arizona, and New Mexico. Attributes for both water and gas chemistry are: Sample name, Sample ID, Type, Collection date, Collection time, Reported location, Reported latitude, Reported longitude, Reported Easting, Reported Northing, Location description, Region, State, County, Latitude, Longitude, Location resolution, Location error, Elevation, Source, Author comment, and Digitizer comment. Attributes for water chemistry are: Well depth, Collection depth, Discharge, Temperature, pH (field), pH (lab), pH, Aluminum (Al), Arsenic (As), Boron (B), Barium (Ba), Bromide (Br), Calcium (Ca), Chloride (Cl), Carbonate (CO3), Alkalinity as carbonate (CO3), Cesium (Cs), Copper (Cu), Dissolved Organic Carbon as Carbon (DIC as C), Fluoride (F), Iron (Fe), Hydrogen sulfide (H2S), Bicarbonate (HCO3), Alkalinity as bicarbonate (HCO3), Carbonic acid (H2CO3), Mercury (Hg), Iodide (I), Potassium (K), Lithium (Li), Magnesium (Mg), Manganese (Mn), Molybdenum (Mo), total Nitrogen (N), Sodium (Na), Ammonium (NH4), Nickel (Ni), Nitrate (NO3), total Phosphorus (P), Lead (Pb), Phosphate (PO4), Rubidium (Rb), Silica (SiO2), Sulfate (SO4), Strontium (Sr), Uranium (U), Vanadium (V), Zinc (Zn), Reported cations, Reported anions, Cations, Anions, Reported total dissolved solids, Salinity, Charge balance, Specific conductance, isotopic composition of hydrogen (Delta 2H), isotopic composition of oxygen in water (Delta 18O (H2O)), Oxygen shift, isotopic composition of oxygen in sulfate (Delta 18O (SO4)), isotopic composition of carbon (Delta 13C), isotopic composition of carbon in dissolved inorganic carbon (Delta 13C (DIC)), Tritium (3H), and 14C. Attributes for gas chemistry are: Temperature, Total gas, argon (Ar), oxygen and argon (O2 + Ar), ethane (C2H6), methane (CH4), carbon dioxide (CO2), hydrogen (H2), hydrogen sulfide (H2S), helium (He), nitrogen (N2), ammonia (NH3), oxygen (O2), dissolved argon (Ar dissolved), dissolved methane (CH4 dissolved), dissolved carbon dioxide (CO2 dissolved), dissolved hydrogen (H2 dissolved), dissolved helium (He dissolved), dissolved nitrogen (N2 dissolved), dissolved ammonia (NH3 dissolved), dissolved oxygen (O2 dissolved), isotopic ratio of helium (3He/4He), isotopic ratio of helium corrected for the atmospheric isotopic composition of helium (3He/4He corrected), isotopic composition of nitrogen (Delta 15N), and isotopic composition of carbon in carbon dioxide (Delta 13C (CO2)).

During October 1995 through March 2014, the U.S. Geological Survey in cooperation with the National Park Service, Luray, Virginia Station collected and analyzed samples of selected springs, air and unsaturated-zone gases in Shenandoah National Park, Virginia. The 19-year record of measurements of chemical and isotopic composition of water discharging from 34 springs located along the crest of the Blue Ridge Mountains in Shenandoah National Park, Virginia, is reported. These data include field measurements of water temperature, specific conductance, concentrations of dissolved oxygen (O2), and pH. Laboratory measurements included major-, minor-, and trace-element chemistry; concentrations of dissolved gases (nitrogen, [N2] argon [Ar], oxygen, and carbon dioxide [CO2]); concentrations of dissolved trace atmospheric gases, including trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), and trichlorotrifluoroethane (CFC-113) and sulfur hexafluoride (SF6); and hydrogen stable isotopic composition (δ2H) and oxygen isotopic composition (δ18O) of water. The data include an up to 14-year time series record of monthly sampling at five springs collected between 1995 and 2013. The measurements included temperature, specific conductance, pH, and discharge recorded at 30-minute intervals. Atmospheric mixing ratios of CFC-11, CFC-12, CFC-113, trifluorobromomethane (CF3Br), SF6, and trifluoromethyl sulfur pentafluoride (SF5CF3) in air from the Big Meadows Air Monitoring Station, Shenandoah National Park, were measured at approximately weekly intervals from September 1995 through March 2014. Additional data include monthly (between May 2001 and August 2003) measurements of temperature, N2, O2, Ar, CO2, CFC-12, CFC-11, CFC-113, and SF6 concentrations in unsaturated-zone air from seven multilevel piezometers in Shenandoah National Park and at the U.S. Geological Survey National Center in Reston, Virginia. All samples were analyzed at the U.S. Geological Survey Laboratories in Reston, Virginia.

During October 1995 through March 2014, the U.S. Geological Survey in cooperation with the National Park Service, Luray, Virginia Station collected and analyzed samples of selected springs, air and unsaturated-zone gases in Shenandoah National Park, Virginia. The 19-year record of measurements of chemical and isotopic composition of water discharging from 34 springs located along the crest of the Blue Ridge Mountains in Shenandoah National Park, Virginia, is reported. These data include field measurements of water temperature, specific conductance, concentrations of dissolved oxygen (O2), and pH. Laboratory measurements included major-, minor-, and trace-element chemistry; concentrations of dissolved gases (nitrogen, [N2] argon [Ar], oxygen, and carbon dioxide [CO2]); concentrations of dissolved trace atmospheric gases, including trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), and trichlorotrifluoroethane (CFC-113) and sulfur hexafluoride (SF6); and hydrogen stable isotopic composition (δ2H) and oxygen isotopic composition (δ18O) of water. The data include an up to 14-year time series record of monthly sampling at five springs collected between 1995 and 2013. The measurements included temperature, specific conductance, pH, and discharge recorded at 30-minute intervals. Atmospheric mixing ratios of CFC-11, CFC-12, CFC-113, trifluorobromomethane (CF3Br), SF6, and trifluoromethyl sulfur pentafluoride (SF5CF3) in air from the Big Meadows Air Monitoring Station, Shenandoah National Park, were measured at approximately weekly intervals from September 1995 through March 2014. Additional data include monthly (between May 2001 and August 2003) measurements of temperature, N2, O2, Ar, CO2, CFC-12, CFC-11, CFC-113, and SF6 concentrations in unsaturated-zone air from seven multilevel piezometers in Shenandoah National Park and at the U.S. Geological Survey National Center in Reston, Virginia. All samples were analyzed at the U.S. Geological Survey Laboratories in Reston, Virginia.

Assessment of biogeochemical processes and transformations at the aquifer-estuary interface and measurement of the chemical flux from submarine groundwater discharge (SGD) zones to coastal water bodies are critical for evaluating ecosystem service, geochemical budgets, and eutrophication status. The U.S. Geological Survey and the University of Delaware measured rates of SGD and concentrations of dissolved constituents, including nitrogen species, from recirculating ultrasonic and manual seepage meters, and in nearshore groundwater, on the southern shore of Guinea Creek, an estuarine tributary of Rehoboth Bay, in Millsboro, Delaware, in June, August, and October of 2015. A novel oxygen- and light-regulated seepage meter and a standard seepage meter were deployed as an adjacent pair and sampled at 0.5- to 2-hour intervals across the majority or entirety of single tidal cycles (8 to 12 hours). SGD rate was measured within an attached collection bag (0.5- to 2-hour intervals), or with an ultrasonic flow sensor (1-second intervals). Groundwater samples were collected at multiple depths (5 to 83 centimeters) in shore-perpendicular transects extending across the nearshore subtidal SGD zone. Constituents and other parameters measured in seepage meters and groundwater included: dissolved oxygen, salinity, pH, oxidation/reduction potential, temperature, nitrate, ammonium, phosphate, dissolved organic and inorganic carbon, stable isotopic ratios of carbon species, trace elements, and alkalinity. These data can be used to evaluate biogeochemical conditions and extent of chemical transformation in the upper coastal aquifer and surface sediments and to calculate fluxes of nitrogen and other constituents carried by SGD across the aquifer-estuary interface.