USGS Sullivan County, PA Baseline Groundwater Survey for 20 Domestic Wells

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A report titled "Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012" published in June 2013 by the U.S. Geological Survey. The testing was done on water wells before any Marcellus Shale drilling and shows a significant number of the wells (7 of the 20) have naturally occurring methane in measurable quantities. Two of the 20 wells have elevated levels of natural methane.

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USGS Sullivan County, PA Baseline Groundwater Survey for 20 Domestic Wells

  1. 1. Prepared in cooperation with thePennsylvania Department of Conservation and Natural Resources,Bureau of Topographic and Geologic SurveyBaseline Groundwater Quality from 20 Domestic Wellsin Sullivan County, Pennsylvania, 2012Scientific Investigations Report 2013–5085U.S. Department of the InteriorU.S. Geological Survey
  2. 2. Cover.  North Mountain, Laporte Township, Sullivan County, Pennsylvania. View is looking southeast from “Wright’s View” acrossthe Muncy Creek Valley.
  3. 3. Baseline Groundwater Quality from20 Domestic Wells in Sullivan County,Pennsylvania, 2012By Ronald A. SlotoPrepared in cooperation with thePennsylvania Department of Conservation and Natural Resources,Bureau of Topographic and Geologic SurveyScientific Investigations Report 2013–5085U.S. Department of the InteriorU.S. Geological Survey
  4. 4. U.S. Department of the InteriorSALLY JEWELL, SecretaryU.S. Geological SurveySuzette M. Kimball, Acting DirectorU.S. Geological Survey, Reston, Virginia: 2013For more information on the USGS—the Federal source for science about the Earth, its natural and livingresources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS.For an overview of USGS information products, including maps, imagery, and publications,visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.govAny use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by theU.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materialsas noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.Suggested citation:Sloto, R.A., 2013, Baseline groundwater quality from 20 domestic wells in Sullivan County, Pennsylvania, 2012:U.S. Geological Survey Scientific Investigations Report 2013–5085, 27 p., http://pubs.usgs.gov/sir/2013/5085/
  5. 5. iiiAcknowledgementsThe cooperation of the residents of Sullivan County who made their wells accessible forsampling is greatly appreciated. The author thanks Taylor Suskie of the Pennsylvania Geologi-cal Survey for her assistance with well location and sampling.ContentsAbstract............................................................................................................................................................1Introduction.....................................................................................................................................................1Purpose and Scope...............................................................................................................................3Description of Study Area....................................................................................................................3Population and Land Use.............................................................................................................3Physiography and Geologic Setting..........................................................................................3Alluvium.................................................................................................................................3Allegheny and Pottsville Formations................................................................................3Mauch Chunk Formation....................................................................................................3Burgoon Sandstone.............................................................................................................5Huntley Mountain Formation.............................................................................................5Catskill Formation................................................................................................................5Lock Haven Formation........................................................................................................5Methods...........................................................................................................................................................6Site Selection.........................................................................................................................................6Sampling and Analytical Methods......................................................................................................6Baseline Groundwater Quality.....................................................................................................................8Physical Properties...............................................................................................................................8Major Ions.............................................................................................................................................12Nutrients................................................................................................................................................12Metals and Trace Elements................................................................................................................12Radionuclides.......................................................................................................................................12Dissolved Gases...................................................................................................................................13Summary........................................................................................................................................................25References Cited..........................................................................................................................................26
  6. 6. ivFigures 1.  Land use and State lands in Sullivan County, Pennsylvania..................................................2 2.  Geology and location of groundwater-sampling sites, Sullivan County,Pennsylvania..................................................................................................................................4 3.  Stratigraphic chart for Sullivan County, Pennsylvania. From Edmunds (1996)....................5 4.  Relation between total dissolved solids and specific conductance for groundwatersamples from wells in Sullivan County, Pennsylvania.............................................................8 5.  Stable isotopic composition of carbon and hydrogen in dissolved methanein two groundwater samples from Sullivan County, Pennsylvania.....................................24Tables 1.  Information on 20 wells sampled in Sullivan County, Pennsylvania, 2012...........................7 2.  Summary statistics for physical properties and dissolved gas concentrationsin water samples from 20 wells sampled in Sullivan County, Pennsylvania, 2012..............9 3.  Physical properties and dissolved gas concentrations for water samplesfrom 20 wells, Sullivan County, Pennsylvania, 2012...............................................................10 4.  U.S. Environmental Protection Agency maximum contaminant, secondarycontaminant, and action levels for constituents in drinking water.....................................11 5.  Summary statistics for concentrations of major ions in water samplesfrom 20 wells, Sullivan County, Pennsylvania, 2012...............................................................14 6.  Concentrations of major ions in water samples from 20 wells, Sullivan County,Pennsylvania, 2012......................................................................................................................15 7.  Summary statistics for concentrations of nutrients in water samplesfrom 20 wells, Sullivan County, Pennsylvania, 2012...............................................................16 8.  Concentrations of nutrients in water samples from 20 wells, Sullivan County,Pennsylvania, 2012......................................................................................................................17 9.  Summary statistics for concentrations of metals and trace elements in samplesfrom 20 wells, Sullivan County, Pennsylvania, 2012. .............................................................18 10.  Concentrations of metals and trace elements in samples from 20 wells,Sullivan County, Pennsylvania, 2012.........................................................................................20 11.  Summary statistics for concentrations and activities of radioactive constituentsin samples from 20 wells, Sullivan County, Pennsylvania, 2012...........................................22 12.  Concentrations and activities of radioactive constituents in samplesfrom 20 wells, Sullivan County, Pennsylvania, 2012...............................................................23
  7. 7. vConversion FactorsInch/Pound to SIMultiply By To obtainLengthfoot (ft) 0.3048 meter (m)mile (mi) 1.609 kilometer (km)Areasquare mile (mi2) 2.590 square kilometer (km2)Volumegallon (gal) 3.785 liter (L)Flow rategallon per minute (gal/min) 0.06309 liter per second (L/s)Radioactivitypicocurie per liter (pCi/L) 0.037 becquerel per liter (Bq/L)Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:°F=(1.8×°C)+32Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:°C=(°F-32)/1.8Vertical coordinate information is referenced to the North American Vertical Datum of 1988(NAVD 88).Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).Elevation, as used in this report, refers to distance above the vertical datum.AbbreviationsAMCL alternate maximum contaminant levelsMCL maximum contaminant levelPaGS Pennsylvania Geological SurveySMCL secondary maximum contaminant levelUSEPA U.S. Environmental Protection AgencyUSGS U.S. Geological Surveyµg/L micrograms per litermg/L milligrams per literµS/cm microsiemens per centimeter at 25 degrees CelsiuspCi/L picocuries per liter
  8. 8. vi(This page intentionally left blank.)
  9. 9. Baseline Groundwater Quality from 20 Domestic Wells inSullivan County, Pennsylvania, 2012By Ronald A. SlotoAbstractWater samples were collected from 20 domestic wellsduring August and September 2012 and analyzed for 47 con-stituents and properties, including nutrients, major ions, metalsand trace elements, radioactivity, and dissolved gases, includ-ing methane and radon-222. This study, done in cooperationwith the Pennsylvania Department of Conservation and Natu-ral Resources, Bureau of Topographic and Geologic Survey(Pennsylvania Geological Survey), provides a groundwater-quality baseline for central and southern Sullivan County priorto drilling for natural gas in the Marcellus Shale.The analytical results for the 20 groundwater samplescollected during this study indicate that only one constituent(gross-alpha radioactivity) in one sample was found to exceedthe U.S. Environmental Protection Agency (USEPA) primarydrinking water maximum contaminant level (MCL). Watersamples from 85 percent of the sampled wells exceeded theproposed USEPA MCL of 300 picocuries per liter (pCi/L)for radon-222; however, only two water samples (10 percentof sampled wells) exceeded the proposed USEPA alternatemaximum contaminant level (AMCL) of 4,000 pCi/L forradon-222. In a few samples, the concentrations of total dis-solved solids, iron, manganese, and chloride exceeded USEPAsecondary maximum contaminant levels (SMCL). In addition,water samples from two wells contained methane concentra-tions greater than 1 milligram per liter (mg/L).In general, most of the water-quality problems involveaesthetic considerations, such as taste or odor from elevatedconcentrations of total dissolved solids, iron, manganese, andchloride that develop from natural interactions of water androck minerals in the subsurface. The total dissolved solidsconcentration ranged from 31 to 664 mg/L; the median was130 mg/L. The total dissolved solids concentration in onewater sample exceeded the USEPA SMCL of 500 mg/L.Chloride concentrations ranged from 0.59 to 342 mg/L; themedian was 12.9 mg/L. The concentration of chloride inone water sample exceeded the USEPA SMCL of 250 mg/L.Concentrations of dissolved iron ranged from less than 3.2 to6,590 micrograms per liter (µg/L); the median was 11.5 µg/L.The iron concentration in samples from 20 percent of thesampled wells exceeded the USEPA SMCL of 300 µg/L.Concentrations of dissolved manganese ranged from less than0.13 to 1,710 µg/L; the median was 38.5 µg/L. The manganeseconcentration in samples from 35 percent of the sampled wellsexceeded the USEPA SMCL of 50 µg/L.Activities of radon-222 ranged from 169 to 15,300 pico-curies per liter (pCi/L); the median was 990 pCi/L. The grossalpha-particle radioactivity ranged from below detection to33 pCi/L; the median was 1.5 pCi/L. The gross alpha-particleradioactivity of one water sample exceeded the USEPA MCLof 15 pCi/L.Concentrations of dissolved methane ranged from lessthan 0.001 to 51.1 mg/L. Methane was not detected in watersamples from 13 wells, and the methane concentration wasless than 0.07 mg/L in samples from five wells. The highestdissolved methane concentrations were 4.1 and 51.1 mg/L,and the pH of the water from both wells was greater than 8.Water samples from these wells were analyzed for isotopes ofcarbon and hydrogen in the methane. The isotopic ratio valuesfell in the range for a thermogenic (natural gas) source. Thewater samples from these two wells had the highest concentra-tions of arsenic, boron, bromide, chloride, fluoride, lithium,molybdenum, and sodium of the 20 wells sampled.IntroductionSullivan County, which is located in north central Penn-sylvania (fig. 1), is underlain by the Marcellus Shale. TheMarcellus Shale, which is being exploited for natural gas,lies approximately 6,000 to 9,000 feet (ft) below land surfacein Sullivan County. All of the residents of Sullivan Countyrely on groundwater as a source of water supply. Drillingand hydraulic fracturing of horizontal natural gas wells havethe potential to contaminate freshwater aquifers that providedrinking water and the base flow of streams (Kargbo and oth-ers, 2010; Kerr, 2010; U.S. Environmental Protection Agency,2013a). Since 2006, permits have been issued for 188 Marcel-lus Shale gas wells (Pennsylvania Department of Environ-mental Protection, 2012a), and 67 natural gas wells have beendrilled into the Marcellus Shale in Sullivan County. Most of
  10. 10. 2   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 201276°2076°3076°4041°3041°20EXPLANATIONState landsState parkPennsylvania Bureau of ForestryState gamelandState forestLand useAgriculturalDevelopedForestedOpen water0 84 MILES0 4 8 KILOMETERSSullivan CountyMarcellus ShaleEXPLANATIONState park boundaries from Pennsylvania Department of Conservation and NaturalResources (2011); State forest boundaries from Pennsylvania Department of Conservationand Natural Resources (2010); State gamelands boundaries from Pennsylvania GameCommission (2011); County boundary and roads from Pennsylvania Department ofTransportation (2009a, 2009b); land use from LaMotte (2008)Base from U.S. Geological Survey digital data220220154874287487220WORLDS ENDSTATE PARKPennsylvaniaBureau ofForestryDUSHOREWYOMINGSTATE FORESTFORKSVILLELAPORTESULLIVAN COUNTYLYCOMINGCOUNTYBRADFORDCOUNTYLUZERNECOUNTYCOLUMBIACOUNTYWYOMINGCOUNTYRICKETTS GLENSTATE PARKWYOMINGSTATE FORESTGamelands66Gamelands13Gamelands134Gamelands12Figure 1.  Land use and State lands in Sullivan County, Pennsylvania.
  11. 11. Introduction  3the wells are in the northern part of the county (PennsylvaniaDepartment of Environmental Protection, 2012b).Pre-gas well drilling groundwater-quality data for water-supply wells in the northern part of Sullivan County havebeen collected by the natural-gas industry. However, data arenot available for most of the central and southern part of thecounty. Without baseline data for associated water-quality con-stituents, it is not possible to establish a connection betweengas production activities and the well-water chemistry thatmight be affected. This study, conducted by the U.S. Geo-logical Survey (USGS) in cooperation with the PennsylvaniaDepartment of Conservation and Natural Resources, Bureau ofTopographic and Geologic Survey (Pennsylvania GeologicalSurvey), provides a pre-gas well drilling groundwater-qualitybaseline for the central and southern part of Sullivan County.Purpose and ScopeThis report presents analytical data for water samplesfrom 20 domestic wells sampled in central and southern Sulli-van County in August and September 2012. The water sampleswere analyzed for 47 constituents, including nutrients, majorions, metals and trace elements, radioactivity, and dissolvedgases, including methane and radon-222. The groundwater-quality data and summary statistics are presented for sampledconstituents to provide a pre-gas well drilling baseline.Description of Study AreaSullivan County occupies 450 square miles (mi2) innorth central Pennsylvania (fig. 1). Land-surface eleva-tions are highest (more than 2,500 ft above NAVD 88) in themountains of the southeastern part of the county and lowestin the southwestern part of the county (as low as about 755 ftabove NAVD 88) (U.S. Geological Survey, 2009). Averageannual temperatures in Sullivan County range from about 44to 49 degrees Fahrenheit with the warmest average annualtemperatures occurring in the southwestern part of the countyand the coldest average annual temperatures occurring in themountainous areas in the northwestern, northeastern, andsoutheastern parts of the county (PRISM Group at OregonState University, 2013). Average annual precipitation var-ies from west to east with an average of 40 inches in thewestern part of the county and an average of 54 inches in theeastern part of the county (PRISM Group at Oregon StateUniversity, 2013).Population and Land UseSullivan County is rural with a population of 6,496 in2010 (U.S. Census Bureau, 2013). The 2010 population isless than double the population in 1850 (Sullivan CountyPlanning and Economic Development Office, 2010). Areasmost densely populated are the boroughs of Dushore, Forks-ville, and Laporte (fig. 1) with 2010 populations of 746, 63,and 313, respectively. Seasonal dwellings made up 56 per-cent of housing units in the county in 2010 (U.S. CensusBureau, 2013).About 87 percent of the county is forested with approxi-mately 38 percent of forested land consisting of state parks,forests, and gamelands (fig. 1) (LaMotte, 2008). Agriculturallands are typically found in the narrow valley bottoms in thenorthern and south-central part of the county. Approximately10 percent of the county is devoted to agriculture with about5 percent of the county in cropland (Sullivan County Planningand Economic Development Office, 2010). About 3 percent ofthe county consists of developed land.Physiography and Geologic SettingSullivan County is mostly located in the AppalachianPlateaus Physiographic Province (Sevon, 2000). The northernpart of the county is in the Glaciated Low Plateau Section. Thisstudy was conducted in the central and southern parts, whichare divided between the western Deep Valleys Section, andthe eastern Glaciated High Plateaus Section. The Deep ValleysSection is characterized by very deep, angular valleys withsome broad to narrow uplands. The Glaciated High PlateausSection is characterized by broad to narrow, rounded to flat,elongate uplands and shallow valleys.Sullivan County is underlain by bedrock of Pennsylva-nia, Mississippian, and Devonian age (figs. 2 and 3). Allu-vium overlies the bedrock in the stream valleys. The geologicdescriptions below for alluvium and bedrock units croppingout in Sullivan County are from Taylor and others (1983).AlluviumThe thick, unconsolidated deposits of Quaternary age thatfill the stream valleys are collectively called alluvium. Allu-vium, which consists of gravel, sand, and clay, fills some val-leys to depths of over 200 ft. In some areas, the alluvium hasbeen transported relatively long distances as a result of glacialprocesses (outwash), and in other areas, it has been weatheredfrom the nearby rock formations.Allegheny and Pottsville FormationsIn Sullivan County, the rocks of Pennsylvanian age aremapped as the Allegheny and Pottsville Formations, undivided.The Allegheny Formation is composed of sandstone, siltstone,thin beds of limestone, and coal. Reported thicknesses for thisunit are consistently about 300 ft. The upper part of the Potts-ville Formation consists mainly of sandstone, siltstone, thinbeds of coal, and conglomerate. The lower part of the PottsvilleFormation consists predominantly of sandstone. Thicknessestimates for the Pottsville Formation range from 140 to 200 ft.Mauch Chunk FormationThe Mauch Chunk Formation of Mississippian agegenerally consists of two units. The lower unit is interbedded
  12. 12. 4   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Geology from Miles and Whitfield (2001)SU-167SU-166SU-165SU-164SU-163SU-162SU-161SU-159SU-157SU-155SU-154SU-153SU-152SU-151SU-150SU-149SU-148SU-158SU-160SU-15676°2076°3076°4041°3041°200 84 MILES0 4 8 KILOMETERSBase from U.S. Geological Survey digital dataLYCOMINGCOUNTYBRADFORDCOUNTYLUZERNECOUNTYCOLUMBIACOUNTYWYOMINGCOUNTYGeologyAllegheny and Pottsville Formations, undividedPottsville FormationMauch Chunk FormationBurgoon Sandstone of the Pocono FormationHuntley Mountain FormationCatskill FormationLock Haven FormationSU-150 Sampled well andidentification numberEXPLANATIONSULLIVAN COUNTYFigure 2.  Geology and location of groundwater-sampling sites, Sullivan County, Pennsylvania.
  13. 13. Introduction  5SYSTEMPennsylvanianQuaternaryAllegheny FormationalluviumGEOLOGIC UNIT LITHOLOGYMauch Chunk FormationPottsville FormationBurgoon Sandstone MemberMississippianCatskill FormationHuntley Mountain FormationDevonianPoorly sorted clay, sand,and gravelSandstone, siltstone,limestone, and coalLock Haven FormationAlleghenyandPottsvilleFormations,undividedPoconoFormationSandstone, siltstone,coal, and conglomerateSandstone, siltstone, shale,and mudstoneSandstone, shale,conglomerate, andmudstoneSandstone, siltstone, andshaleSandstone, siltstone, shale,and conglomerateSandstone, siltstone, shale,and conglomerateFigure 3.  Stratigraphic chart for Sullivan County, Pennsylvania. From Edmunds (1996).sandstone, siltstone, shale, and mudstone. The upper unit isa light-gray calcareous quartz sandstone. The Mauch ChunkFormation is up to 300 ft thick.Burgoon SandstoneThe Mississippian age Burgoon Sandstone Member ofthe Pocono Formation is informally divided into two units.The upper unit consists of light-gray, fine- to medium-grained,well-sorted, pure quartz sandstone (orthoquartzite). The lowerunit consists of gray sandstone and minor interbedded grayshale, conglomerate, and mudstone. Reported thicknesses forthe upper member range from 120 to 240 ft. Reported thick-nesses for the lower member range from 570 to 800 ft.Huntley Mountain FormationThe Huntley Mountain Formation of Late Devonianand Early Mississippian age consists of greenish-gray tolight olive-gray sandstone and some thin beds of grayish-redsiltstone or clay shale. The formation is reported to be about600 ft thick.Catskill FormationThe Catskill Formation of Devonian age consists of asuccession of grayish-red sandstone, siltstone, and shale withsome gray sandstone and conglomerate. The sandstone layersare generally fine grained and thin bedded. The thickness ofthe Catskill Formation varies from about 1,200 to 2,000 ft.Lock Haven FormationThe Lock Haven Formation of Devonian age is composedpredominantly of light olive gray interbedded sandstone,siltstone, shale, and a few thin beds of conglomerate nearthe top. No wells completed in the Lock Haven Formationwere sampled.
  14. 14. 6   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012MethodsWater samples were collected from 20 domestic wells(table 1 and fig. 2) during August and September 2012 andanalyzed to characterize their physical and chemical qual-ity. Samples were analyzed for 47 constituents and proper-ties, including nutrients, major ions, metals and trace ele-ments, radioactivity, and dissolved gases, including methaneand radon-222. Two samples, one field blank and onereplicate sample, were collected for quality assurance andquality control.Site SelectionSelection of water wells for sampling was made by theUSGS in consultation with the Pennsylvania GeologicalSurvey (PaGS). Wells were selected from the PennsylvaniaGroundwater Information System database (PennsylvaniaGeological Survey, 2012). Only wells with construction dataon file were considered. A field reconnaissance was conductedto locate 20 wells, obtain permission to sample, and verify thatany treatment systems could be bypassed. All wells selectedfor sampling are private domestic wells (table 1).Sampling and Analytical MethodsThe USGS and PaGS sampled the wells by using stan-dard USGS field-sampling protocols. Samples were collectedat an untreated tap, typically at a pressure tank and before anyfiltration, water softening, or bacteriological treatment. Watersamples were analyzed in the field for physical properties anddissolved oxygen and shipped overnight to laboratories foranalysis for major ions, nutrients, metals and trace elements,gross alpha and beta radioactivity, and dissolved gases. Thesamples were collected from each well and processed foranalysis by methods described in USGS manuals for the col-lection of water-quality data (U.S. Geological Survey, vari-ously dated).Sampling was done at all well sites using the followingsteps. (1) The existing submersible well pump was turned onand allowed to run. (2) A raw-water tap between the well andthe pressure tank was opened, and the water was allowed toflush to ensure that the water was representative of the aquifer.(3) The water was analyzed with a multiprobe meter for physi-cal properties (temperature, specific conductance, and pH) anddissolved oxygen concentration. (4) After the measurements ofthese physical properties stabilized, pre-rinsed sample bottleswere filled according to USGS protocols (U.S. Geological Sur-vey, variously dated). Samples were collected through a shortpiece of silicone tubing attached to the raw-water tap, whichavoided all water-treatment systems.The analyses for physical properties, radioactivity, anddissolved gases were done on unfiltered water samples toobtain total concentrations. Samples for dissolved concentra-tions of nutrients, major ions, and metals and trace elementswere filtered through a pre-rinsed 0.45-micrometer cellulosecapsule filter. To prevent sample degradation, nitric acid wasadded to the major ion and metals and trace-element samples.Samples for radon analysis were obtained through an inlineseptum with a gas-tight syringe to avoid atmospheric contact.Samples for gross alpha and beta radioactivity and dissolvedgases were obtained through silicon tubing that was placed inbottles that were filled and stoppered while submerged in a5-liter beaker of pumped water to avoid atmospheric contact.The samples were stored on ice in coolers and shippedby overnight delivery to the following three laboratories:(1) the USGS National Water Quality Laboratory in Denver,Colorado, for analysis of major ions, nutrients, metals andtrace elements, and radon; (2) a USGS contract laboratory inCalifornia for analysis of gross alpha and beta radioactivity;and (3) the USGS Chlorofluorocarbon Laboratory in Reston,Virginia, for analysis of methane and other dissolved gases.Descriptions of analytical methods for all constituents exceptthe dissolved gases and isotopes are available through theU.S. Geological Survey (2012a); the methods for determina-tion of dissolved gases in water are described by the U.S.Geological Survey (2012b). The analytical results are avail-able through the USGS National Water Information System(U.S. Geological Survey, 2012c).Water samples containing methane concentrationsgreater than 1 milligram per liter (mg/L) were shipped onice to a contract laboratory in Illinois for hydrocarbon andisotopic analysis. The stable carbon isotopes 12C and 13C andthe stable hydrogen isotopes 1H (protium) and 2H (deuterium)were determined. For the determination of carbon and hydro-gen isotopic ratios for hydrocarbons in a gas mixture, indi-vidual hydrocarbons were first separated and then convertedinto carbon dioxide and water for mass-spectrometric analy-sis. The hydrocarbons were separated from the water sampleby using a gas chromatograph and channeled into a combinedcombustion-collection unit. The combined combustion-collec-tion unit has quartz combustion tubes filled with cupric oxideto convert the hydrocarbons into carbon dioxide and water,which are then collected and purified for isotopic analysis.The carbon dioxide was transferred into Pyrex tub-ing and sealed for mass spectrometric analysis. The 13C/12Cratio was determined by a mass spectrometric analysis thatcompared the sample to a reference standard. The carbonisotope ratio value (δ13C) is reported in terms of per mil (‰)notation with respect to the Vienna Peedee Belemnite (VPDB)standard. Water samples for hydrogen isotope analysis weresealed into Pyrex tubing along with a measured quantity ofzinc. Each sample tube was reacted in a heating block at500°C for 35 minutes to generate hydrogen gas. Once thesample had been reacted, the 1H/2H ratio was determined bymass spectrometric analysis that compared the sample to areference standard. The hydrogen isotope ratio value (δD)is reported in terms of per mil notation with respect to theVienna Standard Mean Ocean Water (VSMOW) standard(Alan R. Langenfeld, Isotech Laboratories, Inc., written com-mun., 2012).
  15. 15. Methods  7Table 1.  Information on 20 wells sampled in Sullivan County, Pennsylvania, 2012.[Well locations are shown in figure 2. --, information not available; >, greater than; R, reported]Well-identificationnumberDatesampledWell depth(feet belowland surface)Casinglength(feet)Yield(gallonsper minute)Depth towater(feet belowland surface)Geologic unitSU-148 8/22/2012 245 20 15 -- Mauch Chunk FormationSU-149 8/20/2012 250 50 30 >140 Burgoon Sandstone member of the Pocono FormationSU-150 8/14/2012 440 40 10 -- Burgoon Sandstone member of the Pocono FormationSU-151 8/15/2012 340 41 10 -- Catskill FormationSU-152 8/15/2012 115 40 23 -- Huntley Mountain FormationSU-153 8/15/2012 250 67 9 -- Huntley Mountain FormationSU-154 8/14/2012 248 129 15 -- Huntley Mountain FormationSU-155 8/23/2012 145 81 5 -- Mauch Chunk FormationSU-156 8/16/2012 250 30 2 100 R Catskill FormationSU-157 8/21/2012 280 268 10 114.1 Huntley Mountain FormationSU-158 8/22/2012 46 12 6 15 R Huntley Mountain FormationSU-159 8/23/2012 104 104 20 30 R AlluviumSU-160 8/15/2012 500 40 1.5 235.4 Catskill FormationSU-161 9/5/2012 200 50 15 50 R Burgoon Sandstone member of the Pocono FormationSU-162 8/21/2012 140 60 >25 -- Huntley Mountain FormationSU-163 8/21/2012 100 54 15 -- Burgoon Sandstone member of the Pocono FormationSU-164 8/22/2012 300 40 30 -- Allegheny and Pottsville Formations, undividedSU-165 8/20/2012 440 60 6 -- Catskill FormationSU-166 8/23/2012 180 30 4 80 R Mauch Chunk FormationSU-167 8/27/2012 200 40 10 -- Mauch Chunk Formation
  16. 16. 8   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Baseline Groundwater QualityAnalytical results for the 20 groundwater samples col-lected during this study are provided in the following sections.The quality of the sampled groundwater was generally withinU.S. Environmental Protection Agency (USEPA) standards,although in some samples, the concentrations of certainconstituents exceeded drinking-water standards (U.S. Environ-mental Protection Agency, 2006, 2012). In general, most of thewater-quality problems involve aesthetic considerations, suchas taste or odor from excessive dissolved solids, iron, man-ganese, and chloride that develop from natural interactions ofwater and rock minerals in the subsurface.The quality assurance/quality control (QA/QC) field-blank sample contained no constituent in concentrationsgreater than the laboratory reporting levels; this indicatesthat no contamination occurred through the sampling oranalytical procedures.The difference in concentration between the sampleand the QA/QC replicate sample (well SU-162) ranged from0 to 2.5 percent for major ions and nutrients. Variability wasconsidered acceptable if the difference was less than 5 percent.The difference in concentration between the sample and theQA/QC replicate sample (well SU-162) for metals and traceelements ranged from 0.5 to 47.5 percent; the median differ-ence was 2.2 percent. The analytes with the largest percentdifferences in concentrations between the sample and itsreplicate were low-concentration analytes where the concen-trations were near the laboratory reporting level. The greatestdifference (47.5 percent) was for molybdenum; the differencein concentration between the sample (0.137 µg/L) and thereplicate sample (0.072 µg/L) was 0.065 µg/L. The laboratorydetection limit for molybdenum was 0.014 µg/L. The rangein measured molybdenum concentrations was from less than0.014 to 3.78 µg/L.Physical PropertiesPhysical properties include temperature, pH, and specificconductance. These properties are unstable and are determinedin the field at the time a water sample is collected. Alkalinityand dissolved oxygen concentration also are determined inthe field. Alkalinity was determined for several samples in thelaboratory. Summary statistics for physical properties are givenin table 2, and field values and analytical results are providedin table 3.The USEPA has set maximum contaminant levels (MCLs)and secondary maximum contaminant levels (SMCLs) forsome constituents in drinking water (table 4). MCLs generallyare set because elevated concentrations of these constituentsmay cause adverse health effects. SMCLs generally are set foraesthetic reasons; elevated concentrations of these constituentsmay impart an undesirable taste or odor to water.pH is a measurement of the activity of hydrogen ionsin water. pH is expressed in logarithmic units with a pH of 7considered neutral. Water with a pH less than 7 is acidic;water with a pH greater than 7 is basic. pH values in thisstudy ranged from 5.0 to 8.8; the median pH was 6.8 (table 2).The pH of 10 of the 20 samples (50 percent) was outside theUSEPA SMCL range of 6.5 to 8.5 (U.S. Environmental Protec-tion Agency, 2012). Nine samples had a pH less than 6.5, andone sample had a pH greater than 8.5 (table 3).Water samples from the Burgoon Sandstone Member ofthe Pocono Formation were the most acidic. The median pH ofwater samples from the Burgoon Sandstone Member was 5.9;from the Mauch Chunk Formation, 6.6; from the Catskill For-mation, 6.9, and from the Huntley Mountain Formation, 7.0.The alkalinity of a solution is a measure of the capac-ity for solutes it contains to react with and neutralize acid(Hem, 1985, p. 106). Alkalinity ranged from 6.4 to 134 mg/Las calcium carbonate; the median concentration was62.3 mg/L (table 2). Alkalinity is related to the pH of a watersample. In general, water samples with a higher pH have ahigher alkalinity.Specific conductance is a measurement of the ability ofwater to conduct an electric current. Specific conductanceranged from 42 to 1,280 microsiemens per centimeter (µS/cm);the median specific conductance was 218 µS/cm (table 2).Median specific conductance values ranged from 187 µS/cmfor the Catskill Formation to 248 µS/cm for the Huntley Moun-tain Formation. Specific conductance is related to the dissolvedsolids concentration of a water sample (r2 = 0.98, fig. 4). Themean ratio of specific conductance to total dissolved solids was0.63 for 20 water samples.Dissolved oxygen concentrations ranged from 0.1 to9.1 mg/L; the median concentration was 4.3 mg/L (table 2).Median dissolved oxygen concentrations ranged from 1.5 mg/Lfor the Huntley Mountain Formation to 4.7 mg/L for the Bur-goon Sandstone Member.01002003004005006007008000 200 400 600 800 1,000 1,200 1,400Specific conductance, in microsiemens per centimeterat 25 degrees CelsiusTotaldissovledsolids,inmilligramsperliterFigure 4.  Relation between total dissolved solids and specificconductance for groundwater samples from wells in SullivanCounty, Pennsylvania
  17. 17. Baseline Groundwater Quality   9Table2. Summarystatisticsforphysicalpropertiesanddissolvedgasconcentrationsinwatersamplesfrom20wellssampledinSullivanCounty,Pennsylvania,2012.[DissolvedgassamplesanalyzedbytheU.S.GeologicalSurveyChlorofluorocarbonLaboratoryinReston,Virginia;mg/L,milligramsperliter;μS/cm,microsiemenspercentimeterat25degreesCelsius;CaCO3,calciumcarbonate;<,lessthan;--,unabletocomputestatistic]ConstituentorpropertyAllwellsBurgoonSandstoneMemberofthePoconoFormation(n=4)CatskillFormation(n=4)HuntleyMountainFormation(n=6)MauchChunkFormation(n=4)MinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumpH,field(standardunits)5.06.88.85.05.96.25.76.98.45.87.08.85.66.67.1Specificconductance,field(μS/cm)422181,280422153701251871,28045248418129227387Oxygen,dissolved,field(mg/L)0.14.39.10.34.75.60.93.27.90.21.59.10.12.57.3Temperature(degreesCelsius)9.011.112.49.810.511.810.111.412.49.010.112.39.411.111.6Alkalinity(mg/LasCaCO3)6.462.31346.444.062.238.771.510516.267.713424.662.078.2Methane,dissolved(mg/L)<0.001<0.00151.1<0.001<0.0010.063<0.001<0.0014.1<0.001<0.00151.1<0.001--0.052Carbondioxide,dissolved(mg/L)0.3521.812047.054.31200.5620.190.40.3512.636.47.0732.986.9Nitrogengas,dissolved(mg/L)17.220.431.6*18.920.123.017.220.022.217.620.622.318.920.724.1Argon,dissolved(mg/L)0.660.731.06*0.680.710.740.660.700.760.660.730.780.690.740.80*AlleghenyandPottsvilleFormations,undivided.
  18. 18. 10   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Table3. Physicalpropertiesanddissolvedgasconcentrationsforwatersamplesfrom20wells,SullivanCounty,Pennsylvania,2012.[Locationsareshowninfigure2;siteinformationislistedintable1.DissolvedgassamplesanalyzedbytheU.S.GeologicalSurveyChlorofluorocarbonLaboratoryinReston,Virginia;mg/L,milligramsperliter;<,lessthan;μS/cm,microsiemenspercentimeterat25degreesCelsius;--,nodata;CaCO3,calciumcarbonate.Boldvaluesexceeddrinking-waterstandard]Well-identificationnumberpH,field(standardunits)Specificconductance,field(μS/cm)Oxygen,dissolved,field(mg/L)Temperature(degreesCelsius)Alkalinity,field,asCaCO3(mg/L)Alkalinity,lab,asCaCO3(mg/L)Methane,dissolved(mg/L)Carbondioxide,dissolved(mg/L)Nitrogengas,dissolved(mg/L)Argon,dissolved(mg/L)SU-1486.81430.39.4--78.20.00219.921.80.77SU-1496.23705.611.062.2--<0.00153.118.90.68SU-1505.82570.39.8--44.80.0612021.20.73SU-1518.41,2800.911.277.3--4.10.622.20.76SU-1527.22870.69.097.0--<0.00113.221.70.74SU-1536.34187.910.142.1--<0.00136.420.60.73SU-1548.83300.210.0--13451.10.419.10.66SU-1556.33110.111.0--61.70.0545.924.10.80SU-1566.91477.912.465.7--<0.00118.117.20.66SU-1576.71112.411.440.0--<0.00111.920.60.73SU-1585.8459.112.3--16.2<0.00132.417.60.67SU-1597.02327.411.5--63.6<0.0016.320.20.73SU-1606.92265.210.1105--<0.00122.119.70.71SU-1616.01723.810.043.1--<0.00147.023.00.74SU-1627.42090.29.393.3--0.0028.922.30.78SU-1635.0425.511.8--6.4<0.00155.519.10.70SU-1647.01715.611.8--90.40.00221.531.61.06SU-1655.71251.111.638.7--<0.00190.420.30.70SU-1665.63874.811.6--24.6<0.0017.118.90.72SU-1677.11297.311.162.3--<0.00186.919.50.69
  19. 19. Baseline Groundwater Quality   11Table 4.  U.S. Environmental Protection Agency maximum contaminant, secondarycontaminant, and action levels for constituents in drinking water.[From U.S. Environmental Protection Agency (2012). μg/L, micrograms per liter; mg/L, milligrams perliter; pCi/L, picocuries per liter; --, no standard; N, nitrogen]Regulated constituentMaximumcontaminant levelAction level1 Secondary maximumcontaminant levelAluminum -- -- 50–200 μg/LAntimony 6 μg/L -- --Arsenic 10 μg/L -- --Barium 2 mg/L -- --Beryllium 4 μg/L -- --Cadmium 5 μg/L -- --Chromium, total 100 μg/L -- --Chloride -- -- 250 mg/LCopper -- -- 1,000 μg/LFluoride 4 mg/L -- 2 mg/LIron -- -- 300 μg/LLead -- 15 μg/L --Manganese -- -- 50 μg/LNitrate as N 10 mg/L -- --Nitrite 1 mg/L -- --pH -- -- 6.5–8.5Selenium 50 μg/L -- --Silver -- -- 100 μg/LSulfate -- -- 250 mg/LTotal dissolved solids -- -- 500 mg/LUranium 30 μg/L -- --Zinc -- -- 5 mg/LGross alpha radioactivity 15 pCi/L -- --1Lead is regulated by a treatment technique that requires water purveyors to control the corrosiveness oftheir water. If more than 10 percent of tap-water samples exceed the action level, the water purveyor musttake additional steps.
  20. 20. 12   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Major IonsMajor ions dissolved from soil and rock make up mostof the dissolved solutes in groundwater; the remainder comesmostly from constituents dissolved in precipitation. Summarystatistics for major ions are given in table 5, and analyticalresults are provided in table 6. Major ions, in order of decreas-ing median concentration, were calcium, chloride, sodium,sulfate, silica, magnesium, potassium, fluoride, and bromide.Total dissolved solids (tables 5 and 6) is a measurementof the total solutes in water. The USEPA SMCL for total dis-solved solids in drinking water is 500 mg/L. The total dis-solved solids concentration ranged from 31 to 664 mg/L; themedian concentration was 130 mg/L. Median total dissolvedsolids concentrations ranged from 123 mg/L in the CatskillFormation to 144 mg/L in the Huntley Mountain Formation.The total dissolved solids concentration in water from onesample exceeded the SMCL. The elevated total dissolvedsolids concentration (664 mg/L) in the water sample fromwell SU-151 in the Catskill Formation was caused by elevatedconcentrations of sodium and chloride. The likely cause of theelevated sodium and chloride is connate water in the formationand a zone of restricted groundwater flow that limits flushing.Chloride concentrations ranged from 0.59 to 342 mg/L;the median concentration was 12.9 mg/L. Median chlorideconcentrations ranged from 6.18 mg/L in the Catskill Forma-tion to 39.6 mg/L in the Burgoon Sandstone Member. Theconcentration of chloride (342 mg/L) in the water samplefrom well SU-151 in the Catskill Formation (the geologic unitwith the lowest median chloride concentration) exceeded theUSEPA SMCL of 250 mg/L for chloride (tables 5 and 6).NutrientsNutrients include nitrogen and phosphorus species.Nitrogen is found in water principally as nitrate (NO3), nitrite(NO2), and ammonia (NH4). The presence of nutrients gener-ally is an indicator of an anthropogenic source(s) of nitrogen,which in groundwater might include fertilizers, storm runoff,animal wastes, and effluent from septic systems. Summary sta-tistics for nutrients are given in table 7, and analytical resultsare provided in table 8. Concentrations of nutrients in samplesfrom the 20 wells were low. Nitrite, ammonia, and orthophos-phorus were present in concentrations less than 0.3 mg/L.Median concentrations of ammonia (less than 0.01 mg/L) andnitrite (less than 0.001 mg/L) were below the laboratory detec-tion limit.Nitrate is the most prevalent nitrogen species in ground-water (table 7). Because concentrations of nitrite are so low,nitrate plus nitrite concentrations represent nitrate concentra-tions. The concentration of nitrate as nitrogen ranged fromless than 0.04 to 1.95 mg/L; the median concentration was0.245 mg/L. All nitrate concentrations were well below theUSEPA MCL of 10 mg/L.Metals and Trace ElementsMetals and other trace elements typically are present inconcentrations less than 1 mg/L in natural waters (Hem, 1985).Most of the metals and trace elements in natural groundwaterare leached from the soil or dissolved from the underlyingbedrock in minute quantities by circulating groundwater. Someare present in precipitation.Summary statistics for metals and trace elements arelisted in table 9, and analytical results are provided in table 10.The USEPA has established MCLs and SMCLs for some ofthese constituents in drinking water (table 4). Of these con-stituents, only iron and manganese concentrations exceededthe USEPA water-quality standards (table 9).Elevated concentrations of iron may cause the water tobe a yellowish or orange color. Elevated concentrations of ironand manganese in water may impart a bitter taste and stainlaundry and plumbing fixtures. Concentrations of dissolvediron in water from the 20 sampled wells ranged from less than3.2 to 6,590 µg/L; the median concentration was 11.5 µg/L(table 9). Median dissolved iron concentrations ranged from4.82 µg/L for the Huntley Mountain Formation to 154 µg/Lfor the Mauch Chunk Formation. Water samples from 4 of the20 sampled wells (20 percent) exceeded the USEPA SMCL of300 µg/L. Sources of iron in well water include minerals in thebedrock, corrosion of iron well casings, and bacterial activity.Concentrations of dissolved manganese in water from the20 sampled wells ranged from less than 0.13 to 1,710 µg/L;the median concentration was 38.5 µg/L (table 9). Medianmanganese concentrations ranged from 4.37 µg/L for theCatskill Formation to 336 µg/L for the Mauch Chunk Forma-tion. Water samples from 7 of the 20 sampled wells (35 per-cent) exceeded the USEPA SMCL of 50 µg/L. Three of thefour water samples (75 percent) from the Mauch ChunkFormation exceeded the USEPA SMCL for manganese.RadionuclidesAnalyses for radioactivity and radionuclides includedgross alpha radioactivity, gross beta radioactivity, and dis-solved radon-222 (radon gas). Uranium, a radioactive element,also was analyzed. Although radionuclides are naturally pres-ent in the groundwater of Sullivan County, they may presenta health problem if activities are elevated (see U.S. Environ-mental protection Agency, 2013b). Summary statistics forradioactive constituents are given in table 11, and analyticalresults are provided in table 12. The USEPA has establishedor proposed MCLs for some of these constituents in drinkingwater (table 4).Radioactivity is the release of energy and energetic par-ticles by changes in the structure of certain unstable elementsas they break down to form more stable arrangements. Radio-active energy is released as (1) alpha radiation consisting ofpositively charged helium nuclei, (2) beta radiation consisting
  21. 21. Baseline Groundwater Quality   13of electrons or positrons, and (3) gamma radiation consistingof electromagnetic waves.The most commonly used unit for radioactivity in wateris picocuries per liter (pCi/L). One Curie is the activity of1 gram of radium, which is equal to 3.7 × 1010atomic disinte-grations per second. Activity refers to the number of particlesemitted by a radionuclide. The rate of decay is proportionalto the number of atoms present and inversely proportionalto half-life. The half-life is the amount of time it takes for aradioactive element to decay to one half its original quantity.Naturally occurring radioactivity in groundwater is pro-duced primarily by the radioactive decay of uranium-238 andthorium-232. These isotopes disintegrate in steps, forming aseries of radioactive nuclide “daughter” products, mostly shortlived, until a stable lead isotope is produced. The uranium-238decay series produces the greatest amount of radioactivity innatural ground water (Hem, 1985, p. 147). Uranium-238 hasa half-life of 4.5 × 109years. Its daughter products includeradium-226 (half-life of 1,620 years) and radon-222 (half-lifeof 3.8 days). Radon-222, a decay product of radium-226, is acolorless, odorless, chemically inert, alpha-particle-emittinggas, which is soluble in water. The end product of the decayseries is the stable isotope lead-206.Activities of radon-222 in water from the 20 sampledwells ranged from 169 to 15,300 pCi/L; the median activitywas 990 pCi/L (table 11). Median radon-222 activities rangedfrom 680 pCi/L in the Mauch Chunk Formation to 1,390 pCi/Lin the Catskill Formation. The USEPA does not currentlyregulate radon-222 in drinking water. However, under theframework specified by the 1999 Notice for the ProposedRadon in Drinking Water Rule (Federal Register, 1999), theUSEPA proposed an alternative maximum contaminant level(AMCL) of 4,000 pCi/L for radon-222 for community watersystems that use groundwater for all or some of the supplyin states with an enhanced indoor radon program. For stateswithout an enhanced indoor air program, the USEPA proposedan MCL of 300 pCi/L for radon-222. Water samples from 17of the 20 wells sampled (85 percent) exceeded the proposedUSEPA MCL of 300 pCi/L; however, only two water samples(10 percent of sampled wells) exceeded the proposed USEPAAMCL of 4,000 pCi/L for radon-222. All four of the watersamples from the Catskill Formation exceeded the proposedUSEPA MCL.The gross alpha-particle radioactivity in water from the20 sampled wells ranged from less than the detection limit to33 pCi/L; the median activity was 1.5 pCi/L (table 11). TheUSEPA has established an MCL of 15 pCi/L for gross alpha-particle activity (table 4). One water sample exceeded theUSEPA MCL.The concentration of uranium ranged from less than0.004 to 6.35 µg/L; the median concentration was 0.152 µg/L.No water samples exceeded the USEPA MCL of 30 µg/Lfor uranium.Dissolved GasesDissolved gases analyzed are methane, carbon dioxide,nitrogen, argon, oxygen, and radon-222. Radon-222 wasdiscussed in the “Radionuclides” section, and oxygen was dis-cussed in the “Physical Properties” section. Summary statisticsfor the other dissolved gases are given in table 2, and analyti-cal results are provided in table 3.Concentrations of dissolved methane ranged from lessthan 0.001 to 51.1 mg/L (table 2). Methane was not detectedin water samples from 13 of the wells (table 3). The dissolvedmethane concentrations in water from two wells, SU-151(Catskill Formation) and SU-154 (Huntley Mountain Forma-tion) were 4.1 and 51.1 mg/L, respectively. A dissolved meth-ane concentration greater than 28 mg/L indicates that poten-tially explosive or flammable quantities of the gas are beingproduced (Eltschlager and others, 2001, p. 40). A very strongodor of hydrogen sulfide was noted during the sampling ofwell SU-154. Water from these 2 wells were the only samplesfrom the 20 wells sampled with a pH greater than 8.Samples of water from wells SU-151 and SU-154were also analyzed for the hydrocarbon gases ethane,ethylene, propane, iso-butane, and N-butane and for thehydrocarbon liquids iso-pentane, N-pentane, and hexane.Ethane concentrations of 0.002 and 0.02 mg/L weremeasured in the water samples from wells SU-151 andSU-154, respectively. The other hydrocarbons werenot detected.Samples of water from wells SU-151 and SU-154 wereanalyzed for isotopes of carbon and hydrogen in the methane.The δ13C values were -48.65 and -42. 37 per mil, and the δDvalues were -170.2 and -226.6 per mil for wells SU-151 andSU-154, respectively. These values fall within the range fora thermogenic natural gas source, rather than a microbial(biogenic) gas source (fig. 5). The water sample from wellSU-151 had the highest concentrations of arsenic, bromide,chloride, lithium, molybdenum, and sodium; the secondhighest concentrations of barium, boron, and strontium; andthe third highest concentrations of fluoride of the 20 wellssampled. The water sample from well SU-154 had the high-est concentrations of boron and fluoride; the second highestconcentration of bromide and sodium; and the third highestconcentration of arsenic, lithium, molybdenum, and strontiumof the 20 wells sampled.
  22. 22. 14   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Table5. Summarystatisticsforconcentrationsofmajorionsinwatersamplesfrom20wells,SullivanCounty,Pennsylvania,2012.[Allconstituentconentrationsareinmilligramsperliter;--,nowater-qualitystandard;n,numberofsamples;<,lessthan]DissolvedconstituentAllwellsBurgoonSandstoneMemberofthePoconoFormation(n=4)CatskillFormation(n=4)HuntleyMountainFormation(n=6)MauchChunkFormation(n=4)MinimumMedianMaximumSecondarymaximumcontaminantlevel1NumberofsamplesexceedingstandardMinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumCATIONSCalcium2.6425.441.9----2.6424.437.114.421.528.66.1720.841.923.026.637.3Magnesium1.072.739.66----1.264.275.851.111.662.421.073.319.662.673.435.75Potassium0.440.904.47----0.532.463.140.551.094.470.440.710.960.771.061.90Sodium0.428.08236----2.264.0727.84.5118.02361.1312.366.40.424.1240.6ANIONSBromide20.0180.0262.68----0.0200.0300.0430.0190.0242.680.0190.0290.260.0190.0290.047Chloride0.5912.934225015.024.672.50.986.18342.00.5917.2940.6623.481.5Fluoride<0.040.060.4520<0.040.040.08<0.040.140.23<0.040.060.45<0.040.060.08Sulfate0.686.9626.125003.298.2814.91.799.0113.20.684.1612.42.096.8626.1OTHERSSilica4.546.208.12----4.546.237.176.296.568.125.215.896.795.866.647.30Totaldissolvedsolids311306645001311282237512366437144318841272511FromU.S.EnvironmentalProtectionAgency(2012).2AlleghenyandPottsvilleFormations,undivided.
  23. 23. Baseline Groundwater Quality   15Table6. Concentrationsofmajorionsinwatersamplesfrom20wells,SullivanCounty,Pennsylvania,2012.[Welllocationsareshowninfigure2;siteinformationislistedintable1.Allconcentrationsareinmilligramsperliter;°C,degreesCelsius;<,lessthan;Boldvaluesexceeddrinking-waterstandard(U.S.EnvironmentalProtectionAgency,2012)]Well-identificationnumberCalcium,dissolvedMagnesium,dissolvedSodium,dissolvedPotassium,dissolvedBromide,dissolvedChloride,dissolvedFluoride,dissolvedSilica,dissolvedSulfate,dissolvedDissolvedsolidsdriedat180°CSU-14825.23.981.150.900.021.750.086.12.0990SU-14937.15.7627.81.820.04372.50.085.3910.3223SU-15025.55.852.873.140.03339.30.067.066.25156SU-15114.41.112361.62.683420.226.761.79664SU-15240.85.219.070.960.0219.10.075.2112.4162SU-15341.99.6621.80.90.03794<0.045.797.36318SU-15413.11.6466.40.600.26134.10.456.790.68206SU-15537.35.757.081.210.04745.10.067.189.8164SU-15628.62.424.510.550.0190.98<0.048.127.9199SU-15715.63.951.170.600.02110.60.055.760.9676SU-1586.171.071.130.440.0190.590.056.356.5537SU-15929.32.3913.50.610.19725.60.056.0311.1134SU-16027.11.8231.30.580.0255.510.236.2913.2147SU-16123.22.785.273.10.0279.88<0.047.1714.9100SU-16225.92.6715.50.810.13315.30.085.981.77125SU-162replicate26.12.6615.40.790.13615.20.085.971.75125SU-1632.641.262.260.530.025.000.024.543.2931SU-16419.26.199.281.430.0180.760.146.14.52109SU-16515.81.494.774.470.0236.850.066.3610.175SU-16627.92.8740.61.90.03981.50.057.326.1251SU-16723.02.670.420.770.0190.66<0.045.863.9184
  24. 24. 16   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Table7. Summarystatisticsforconcentrationsofnutrientsinwatersamplesfrom20wells,SullivanCounty,Pennsylvania,2012.[Allconstituentsareinmilligramsperliter;n,numberofsamples;N,nitrogen;P,phosphorus;<,lessthan;NS,unabletocomputestatistic;--,nowater-qualitystandard]DissolvedconstituentAllwellsBurgoonSandstoneMemberofthePoconoFormation(n=4)CatskillFormation(n=4)HuntleyMountainFormation(n=6)MauchChunkFormation(n=4)MinimumMedianMaximumMaximumcontaminantlevel1MinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumAmmonia,dissolved(asN)<0.01<0.010.241--<0.01NS0.241<0.01<0.010.127<0.01<0.010.124<0.01NS0.081Nitrateplusnitrite,dissolved(asN)<0.040.2451.95--<0.041.021.290.1720.9611.80<0.040.1961.07<0.04NS1.95Nitrate,dissolved(asN)<0.040.2451.9510<0.041.021.290.1720.9581.80<0.040.1961.07<0.04NS1.95Nitrite,dissolved(asN)<0.001<0.0010.0051<0.001<0.0010.001<0.001<0.0010.005<0.001NS0.001<0.001<0.0010.002Orthophosphate,dissolved(asP)<0.004NS0.045--<0.004<0.0040.0120.0050.0120.018<0.004NS0.045<0.004NS0.0171FromU.S.EnvironmentalProtectionAgency(2012).
  25. 25. Baseline Groundwater Quality   17Table 8.  Concentrations of nutrients in water samples from 20 wells, Sullivan County, Pennsylvania, 2012.[Well locations are shown in figure 2; site information is listed in table1. mg/L, milligrams per liter; N, nitrogen; P, phospho-rus; <, less than]Well-identificationnumberAmmonia,dissolved(mg/L as N)Nitrate plusnitrite, dissolved(mg/L as N)Nitrate,dissolved(mg/L as N)Nitrite,dissolved(mg/L as N)Orthophosphate,dissolved(mg/L as P)SU-148 0.075 <0.04 < 0.04 <0.001 <0.004SU-149 0.014 0.256 0.256 <0.001 <0.004SU-150 0.241 <0.04 < 0.039 0.001 <0.004SU-151 0.127 0.332 0.327 0.005 0.005SU-152 <0.01 0.159 0.158 0.001 <0.004SU-153 <0.01 1.07 1.07 0.001 0.005SU-154 0.124 <0.04 < 0.039 0.001 0.045SU-155 0.081 <0.04 < 0.038 0.002 <0.012SU-156 <0.01 1.8 1.8 <0.001 0.018SU-157 <0.01 0.622 0.622 <0.001 <0.004SU-158 <0.01 0.233 0.233 <0.001 0.015SU-159 <0.01 0.415 0.415 <0.001 <0.004SU-160 <0.01 0.172 0.172 <0.001 0.011SU-161 <0.01 1.29 1.29 <0.001 0.012SU-162 0.055 <0.04 <0.04 <0.001 <0.004SU-162 replicate 0.056 < 0.04 <0.04 <0.001 <0.004SU-163 <0.01 0.741 0.741 <0.001 <0.004SU-164 0.229 <0.04 <0.04 <0.001 <0.004SU-165 <0.01 1.59 1.59 <0.001 0.012SU-166 <0.01 1.95 1.95 <0.001 0.017SU-167 <0.01 0.234 0.234 <0.001 0.006
  26. 26. 18   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Table9. Summarystatisticsforconcentrationsofmetalsandtraceelementsinsamplesfrom20wells,SullivanCounty,Pennsylvania,2012.[Allconcentrationsareinmicrogramsperliter;water-qualitystandardsfromU.S.EnvironmentalProtectionAgency(2012);n,numberofsamples;--,nostandard;<,lessthan;NS,couldnotcomputestatistic]DissolvedconstituentAllwellsWater-qualitystandard1NumberofsamplesexceedingstandardPercentageofsamplesexceedingstandardBurgoonSandstoneMemberofthePoconoFormation(n=4)MinimumMedianMaximumMaximumcontaminantlevelActionlevel2SecondarymaximumcontaminantlevelMinimumMedianMaximumAluminum<2.2<2.226.3----50–20000<2.2<2.218.5Antimony<0.027<0.0270.2946----00<0.027NS0.251Arsenic<0.030.308.8510----00<0.030.0930.67Barium5.891401,0502,000----00241591,050Beryllium<0.0060.0100.1254----000.010.0340.125Boron420153----------72291Cadmium<0.016<0.0160.1125----000.021NS0.072Chromium<0.07<0.070.3100----00<0.07<0.070.1Cobalt<0.0210.0628.04----------0.0520.160.47Copper<0.804.2130----1,00000<0.8014.270.6Iron<3.211.56,590----300420<3.201156,590Lead<0.0250.3647.36--15--00<0.0250.8132.48Lithium0.485.73457----------1.296.5941.5Manganese<0.1338.51,710----5073540.142.61,710Molybdenum<0.0140.1263.78----------<0.014NS0.124Nickel<0.090.424.3----------0.421.34.3Selenium<0.030.080.9550----00<0.030.140.95Silver<0.005<0.0050.11----10000<0.005<0.0050.006Strontium13.42212,450----------6471,0481,180Zinc<1.49.244.4----5,0000010.224.725.5
  27. 27. Baseline Groundwater Quality   19Table9. Summarystatisticsforconcentrationsofmetalsandtraceelementsinsamplesfrom20wells,SullivanCounty,Pennsylvania,2012.—Continued[Allconcentrationsareinmicrogramsperliter;water-qualitystandardsfromU.S.EnvironmentalProtectionAgency(2012);n,numberofsamples;--,nostandard;<,lessthan;NS,couldnotcomputestatistic]DissolvedconstituentCatskillFormation(n=4)HuntleyMountainFormation(n=6)MauchChunkFormation(n=4)MinimumMedianMaximumMinimumMedianMaximumMinimumMedianMaximumAluminum<2.24.0626.3<2.2<2.25.12<2.2<2.214.2Antimony0.0430.0840.131<0.027<0.0270.294<0.027<0.0270.092Arsenic0.2173.478.85<0.030.2584.970.0960.9342.54Barium811404155.8916730488170354Beryllium0.0080.0100.057<0.0060.0070.017<0.0060.0140.775Boron94315052515341643Cadmium<0.016NS0.031<0.016<0.016<0.016<0.0160.0300.112Chromium<0.070.10.3<0.07NS0.1<0.07<0.070.2Cobalt0.0630.0650.076<0.0210.0240.037<0.0211.218.04Copper4.722.0130<0.80<0.8021.21.98.670.2Iron<3.207.5884.8<3.204.82523<3.201546,100Lead0.1980.7142.42<0.0250.1431.440.1720.2777.36Lithium0.4815.54570.553.9138.51.916.3819.4Manganese0.344.3769.30.16114.5316<0.13336765Molybdenum0.0441.163.78<0.0140.0961.15<0.0140.1070.335Nickel0.200.301.2<0.090.181.40.212.43.9Selenium0.060.260.53<0.03NS0.15<0.03NS0.55Silver<0.005NS0.11<0.005<0.0050.007<0.005<0.0050.007Strontium45.282.52,38013.41731,2101212122,450Zinc6.68.324.9<1.44.213.32.411.244.41FromU.S.EnvironmentalProtectionAgency(2012).2Leadisregulatedbyatreatmenttechniquethatrequireswaterpurveyorstocontrolthecorrosivenessoftheirwater.Ifmorethan10percentoftap-watersamplesexceedtheactionlevel,thewaterpurveyormusttakeadditionalsteps.
  28. 28. 20   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Table10. Concentrationsofmetalsandtraceelementsinsamplesfrom20wells,SullivanCounty,Pennsylvania,2012.[Welllocationsareshowninfigure2;siteinformationislistedintable1.Allconcentrationsareinmicrogramsperliter;<,lessthan;boldvaluesexceeddrinking-waterstandard]Well-identificationnumberAluminum,dissolvedAntimony,dissolvedArsenic,dissolvedBarium,dissolvedBeryllium,dissolvedBoron,dissolvedCadmium,dissolvedChromium,dissolvedCobalt,dissolvedCopper,dissolvedSU-148<2.20.0922.52460.020210.026<0.078.041.9SU-149<2.20.2510.112880.01891<0.016<0.070.0526.4SU-150<2.2<0.0270.671,0500.05028<0.016<0.070.467<0.80SU-1512.40.0438.94150.0111500.031<0.070.0644.7SU-152<2.20.2940.36286<0.00682<0.016<0.070.021<0.80SU-153<2.2<0.0270.1665.40.0175<0.0160.080.0373.7SU-1545.1<0.0275.03040.007153<0.0160.1<0.021<0.80SU-155<2.2<0.0271.73540.009110.033<0.072.3613.7SU-156<2.20.0951.81210.0089<0.0160.100.07639.3SU-157<2.2<0.027<0.035.89<0.0066<0.016<0.070.029<0.80SU-1583.7<0.0270.148.790.0075<0.0160.110.02421.2SU-159<2.20.0490.2474.2<0.00611<0.016<0.070.031.3SU-1605.720.0745.1810.01066<0.0160.10.0634.7SU-161<2.20.0310.08240.01150.0210.080.21770.6SU-162<2.2<0.0270.372680.01045<0.016<0.070.024<0.80SU-162replicate<2.2<0.0270.392710.00844<0.016<0.07<0.021<0.80SU-16318.5<0.027<0.03290.12570.072<0.070.09522SU-164<2.2<0.0271.33170.01440<0.016<0.070.979<0.80SU-16526.30.1310.221590.057190.0280.30.065130SU-16614.2<0.0270.10940.078430.1120.150.06270.2SU-167<2.2<0.0270.2288.2<0.0064<0.016<0.07<0.0213.5
  29. 29. Baseline Groundwater Quality   21Table10. Concentrationsofmetalsandtraceelementsinsamplesfrom20wells,SullivanCounty,Pennsylvania,2012.—Continued[Welllocationsareshowninfigure2;siteinformationislistedintable1.Allconcentrationsareinmicrogramsperliter;<,lessthan;boldvaluesexceeddrinking-waterstandard]Well-identificationnumberIron,dissolvedLead,dissolvedLithium,dissolvedManganese,dissolvedMolybdenum,dissolvedNickel,dissolvedSelenium,dissolvedSilver,dissolvedStrontium,dissolvedZinc,dissolvedSU-1482920.3528.895980.3351.8<0.03<0.0052658.2SU-149<3.2<0.02511.643.50.1241.40.030.012,45025.1SU-1506,5900.37541.51,710<0.0140.42<0.03<0.0051,15010.2SU-1519.40.19845769.33.780.380.220.119456.6SU-152<3.20.2186.010.160.2740.18<0.030.012,3804.0SU-1534.20.6471.80.440.0240.410.10<0.0051774.5SU-15427.70.03838.536.81.15<0.09<0.03<0.0051,210<1.4SU-1556,1000.17219.47650.0652.9<0.03<0.00516844.4SU-156<3.20.6954.120.400.620.20.31<0.0051598.1SU-1574.7<0.0250.5528.60.0560.130.15<0.00573.4<1.4SU-1585.01.440.560.37<0.0141.40.05<0.00517.513.3SU-159100.155.451.060.1280.170.15<0.0052659.9SU-1605.80.73326.80.341.70.220.53<0.0052658.5SU-161131.251.2940.10.0551.20.95<0.00545.224.3SU-1625230.06820.23160.1370.17<0.03<0.0051,18010.8SU-162replicate5200.04420.13110.0720.13<0.03<0.0051,20010.4SU-1632172.481.5741.6<0.0144.30.24<0.00513.425.5SU-1641,7900.78221.22330.2680.73<0.03<0.0056474.2SU-16584.82.420.488.340.0441.20.060.015024.9SU-16615.87.363.8773<0.0143.90.550.0191.614.2SU-167<3.20.2011.91<0.1300.1480.210.41<0.0051212.4
  30. 30. 22   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Table11. Summarystatisticsforconcentrationsandactivitiesofradioactiveconstituentsinsamplesfrom20wells,SullivanCounty,Pennsylvania,2012.[GrossalphaandbetaradioactivityanalysesbyEberlineCorporationofRedmond,California;μg/L,microgramsperliter;pCi/L,picocuriesperliter;--,nostandard;n,numberofsamples;R,notdetected,resultbelowsamplespecificcriticallevel;<,lessthan;NS,unabletocomputestatistic]ConstituentAllwellsWater-qualitystandardBurgoonSandstoneMemberofthePoconoFormation(n=4)MinimumactivityorconcentrationMedianactivityorconcentrationMaximumactivityorconcentrationMaximumcontaminantlevel1Proposedmaximumcontaminantlevel2NumberofsamplesexceedingstandardPercentageofsamplesexceedingstandardMinimumactivityorconcentrationMedianactivityorconcentrationMaximumactivityorconcentrationGrossalpharadioactivity,total(pCi/L)R1.53315--15R1.833Grossbetaradioactivity,total(pCi/L)R221--------1.12.821Radon-222,dissolved(pCi/L)316999015,300--30017851781,0801,630Uranium,dissolved(μg/L)<0.0040.1526.3530--00<0.0040.0870.465ConstituentCatskillFormation(n=4)HuntleyMountainFormation(n=6)MauchChunkFormation(n=4)MinimumactivityorconcentrationMedianactivityorconcentrationMaximumactivityorconcentrationMinimumactivityorconcentrationMedianactivityorconcentrationMaximumactivityorconcentrationMinimumactivityorconcentrationMedianactivityorconcentrationMaximumactivityorconcentrationGrossalpharadioactivity,total(pCi/L)2.23.29.1RNS2.8RNS4.2Grossbetaradioactivity,total(pCi/L)2.23.64.9R1.24.00.91.75.7Radon-222,dissolved(pCi/L)4101,3901,5004909904,70028068015,300Uranium,dissolved(μg/L)0.2292.046.35<0.0040.0601.580.0050.3461.821FromU.S.EnvironmentalProtectionAgency(2012).2FromFederalRegister(1999).3AlleghenyandPottsvilleFormations,undivided.
  31. 31. Baseline Groundwater Quality   23Table 12.  Concentrations and activities of radioactive constituents insamples from 20 wells, Sullivan County, Pennsylvania, 2012.[Well locations are shown in figure 2; site information is listed in table1; gross alpha andbeta radioactivity analyses by Eberline Corporation of Redmond, California; μg/L, micro-grams per liter; pCi/L, picocuries per liter; --, no replicate sample; R, not detected, resultbelow sample specific critical level, value is critical level; <, less than. Bold values exceeddrinking-water standard or proposed drinking-water standard]Well-identificationnumberGross alpharadioactivity,total(pCi/L)Gross betaradioactivity,total(pCi/L)Radon-222,dissolved(pCi/L)Uranium,dissolved(μg/L)SU-148 4.2 1.8 280 0.636SU-149 33 21 1,480 0.16SU-150 2.4 3.2 178 <0.004SU-151 2.4 4.9 1,390 0.229SU-152 2.8 2.9 1,000 1.58SU-153 R 0.6 1.3 2,640 0.144SU-154 R 1.1 940 0.034SU-155 R 0.6 0.9 670 0.005SU-156 3.9 2.2 1,500 3.44SU-157 1.9 4 4,700 0.086SU-158 R 0.1 R 0.6 980 <0.004SU-159 R 0.2 R 0.3 1,140 0.18SU-160 9.1 2.5 1,390 6.35SU-161 1.2 2.5 670 0.465SU-162 0.9 R 0.3 490 0.01SU-162 replicate -- -- -- 0.009SU-163 R 1.1 1,630 0.015SU-164 0.5 1.7 169 0.005SU-165 2.2 4.7 410 0.644SU-166 R 0.5 1.5 690 0.056SU-167 1.8 5.7 15,300 1.82
  32. 32. 24   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012Microbial Gas(Carbon Dioxide Reduction)Microbial Gas(Acetate Formation)Thermogenic Gas(Natural Gas)SU-151SU-154-380-360-340-320-280-300-260-240-220-200-180-160-140-120-100-90 -80 -70 -60 -50 -40 -30Relative to Vienna Pee Dee Belemnite, in per milδ C ,CH413RelativetoViennaStandardMeanδD,CH4OceanWater,inpermilFigure 5.  Stable isotopic composition of carbon and hydrogen in dissolved methane in twogroundwater samples from Sullivan County, Pennsylvania. Diagram shows process end membersobserved in natural systems (Modified from Coleman and others, 1993, based on the dataset ofSchoell, 1980). Isotope analyses were done by Isotech Laboratories, Inc., in Champaign, Illinois.
  33. 33. Summary  25SummarySullivan County is underlain by the Marcellus Shale,which is being tapped as a source of natural gas. Pre-gas welldrilling groundwater-quality data for water-supply wells inthe northern part of Sullivan County have been collected bythe natural-gas industry; however, data are not available forthe rest of the county. Without baseline data for associatedwater-quality constituents, it is not possible to establish a con-nection between gas production activities and the well-waterchemistry that might be affected. This study, done in coop-eration with the Pennsylvania Department of Conservationand Natural Resources, Bureau of Topographic and GeologicSurvey (Pennsylvania Geological Survey), provides a pre-gaswell drilling groundwater-quality baseline for the central andsouthern parts of Sullivan County.Sullivan County is underlain by surficial bedrock ofPennsylvania, Mississippian, and Devonian ages. Alluviumoverlies the bedrock in the stream valleys. The major bedrockgeologic formations in the county are the Pennsylvanian ageAllegheny and Pottsville Formations, undivided; the Missis-sippian age Mauch Chunk Formation and Burgoon SandstoneMember of the Pocono Formation; and the Devonian ageCatskill and Lock Haven Formations. No wells were sampledin the Lock Haven Formation.Water samples were collected from 20 domestic wells inAugust and September 2012 and analyzed to characterize theirphysical and chemical quality. Samples were analyzed for 47constituents and properties, including nutrients, major ions,metals and trace elements, radioactivity, and dissolved gases,including methane and radon-222. Wells were selected fromthe Pennsylvania Geological Survey (PaGS) PennsylvaniaGroundwater Information System database. Only wells withavailable construction data were considered. All sampled wellsare private domestic wells.The analytical results for the 20 groundwater samplescollected during this study indicate that only one constituent(gross-alpha radioactivity) in one sample was found to exceedthe U.S. Environmental Protection Agency (USEPA) primarydrinking water maximum contaminant level (MCL). Watersamples from 85 percent of the sampled wells exceeded theproposed USEPA MCL of 300 picocuries per liter (pCi/L)for radon-222; however, only two water samples (10 percentof sampled wells) exceeded the proposed USEPA alternatemaximum contaminant level (AMCL) of 4,000 pCi/L forradon-222. In a few samples, the concentrations of total dis-solved solids, iron, manganese, and chloride exceeded USEPAsecondary maximum contaminant levels (SMCL). In addition,water samples from two wells contained methane concentra-tions greater than 1 milligram per liter (mg/L). In general,most of the water-quality problems involve aesthetic consid-erations, such as taste or odor from elevated concentrationsof total dissolved solids, iron, manganese, and chloride thatdevelop from natural interactions of water and rock mineralsin the subsurface.pH ranged from 5.0 to 8.8 with a median value of 6.8.The pH of 50 percent of the sampled wells was outsidethe USEPA SMCL range of 6.5 to 8.5. Nine samples hada pH less than 6.5, and one sample had a pH greater than8.5. The median pH of water samples ranged from 5.9 forthe Burgoon Sandstone Member to 7.0 for the HuntleyMountain Formation.The total dissolved solids concentration ranged from31 to 664 mg/L; the median was 130 mg/L. Median totaldissolved solids concentrations ranged from 123 mg/L in theCatskill Formation to 144 mg/L in the Huntley Mountain For-mation. The total dissolved solids concentrations in one watersample exceeded the SMCL. The elevated total dissolvedsolids concentration (664 mg/L) in water from well SU-151 inthe Catskill Formation was caused by elevated concentrationsof sodium and chloride.Chloride concentrations ranged from 0.5.9 to 342 mg/L;the median was 12.9 mg/L. Median chloride concentrationsranged from 6.18 mg/L in the Catskill Formation to 39.6 mg/Lin the Burgoon Sandstone Member. The concentration of chlo-ride (342 mg/L) in the water sample from well SU-151 in theCatskill Formation exceeded the USEPA SMCL of 250 mg/Lfor chloride.Concentrations of nutrients were low. Nitrite, ammonia,and orthophosphorus were present in concentrations less than0.3 mg/L. Median concentrations were less than the laboratorydetection limit for ammonia and nitrite. Nitrate is the mostprevalent nitrogen species in groundwater. The calculatedconcentration of nitrate as nitrogen ranged from less than 0.04to 1.95 mg/L; the median concentration was 0.245 mg/L. Allnitrate concentrations were well below the USEPA maximumcontaminant level (MCL) of 10 mg/L.Concentrations of dissolved iron ranged from lessthan 3.2 to 6,590 micrograms per liter (µg/L); the medianconcentration was 11.5 µg/L. Median iron concentrationsranged from 4.82 µg/L for the Huntley Mountain Formationto 154 µg/L for the Mauch Chunk Formation. Water samplesfrom 20 percent of the sampled wells exceeded the USEPASMCL of 300 µg/L for iron.Concentrations of dissolved manganese ranged fromless than 0.13 to 1,710 µg/L; the median concentration was38.5 µg/L. Median manganese concentrations ranged from4.37 µg/L for the Catskill Formation to 336 µg/L for theMauch Chunk Formation. Water samples from 35 percent ofthe sampled wells exceeded the USEPA SMCL of 50 µg/Lfor manganese.Activities of radon-222 ranged from 169 to 15,300 pCi/L;the median activity was 990 pCi/L. Median radon-222 activi-ties ranged from 680 pCi/L in the Mauch Chunk Formationto 1,390 pCi/L in the Catskill Formation. Water samplesfrom 85 percent of the sampled wells exceeded the proposedUSEPA MCL of 300 pCi/L for radon-222; however, onlytwo water samples exceeded the proposed USEPAAMCL of4,000 pCi/L. All four of the water samples from the CatskillFormation exceeded the proposed USEPA MCL. The grossalpha-particle radioactivity ranged from less than the detection
  34. 34. 26   Baseline Groundwater Quality from 20 Domestic Wells in Sullivan County, Pennsylvania, 2012limit to 33 pCi/L; the median activity was 1.5 pCi/L. Onewater sample exceeded the USEPA MCL of 15 pCi/L for grossalpha-particle activity.Concentrations of methane ranged from less than 0.001 to51.1 mg/L. Methane was not detected in water samples from13 of the wells. The methane concentration in water from twowells, SU-151 (Catskill Formation) and SU-154 (HuntleyMountain Formation), were 4.1 and 51.1 mg/L, respectively.Ethane concentrations of 0.002 and 0.02 mg/L were measuredin the water samples from SU-151 and SU-154, respectively.A very strong odor of hydrogen sulfide was noted during thesampling of well SU-154. The pH of the water samples forboth wells was greater than 8.Samples of water from wells SU-151 and SU-154 wereanalyzed for isotopes of carbon and hydrogen in the methane.The values fall in the range for thermogenic natural gas, ratherthan microbial (biogenic) gas. The water sample from wellSU-151 had the highest concentrations of arsenic, bromide,chloride, lithium, molybdenum, and sodium; the second high-est concentrations of barium, boron, and strontium; and thethird highest concentration of fluoride of the 20 wells sampled.The water sample from well SU-154 had the highest concen-trations of boron and fluoride; the second highest concentra-tions of bromide and sodium; and the third highest concentra-tions of arsenic, lithium, molybdenum, and strontium of the20 wells sampled.References CitedColeman, D.D., Liu, C.L., Hackley, K.C., and Benson, L.J.,1993, Identification of landfill methane using carbon andhydrogen isotope analysis: Proceedings of Sixteenth Inter-national Madison Waste Conference, University of Wiscon-sin, September 22–23, 1993, p. 303–314.Edmunds, W.E., 1996, Correlation chart showing suggestedrevisions of uppermost Devonian through Permian stra-tigraphy, Pennsylvania: Pennsylvania Geological Survey,4th ser., Open-File Report 96–49, 12 p.Eltschlager, K.K., Hawkins, J.W., Ehler, W.C., and Baldas-sare, Fred, 2001, Technical measures for the investigationand mitigation of fugitive methane hazards in areas of coalmining: U.S. Office of Surface Mining Reclamation andEnforcement, 125 p.Federal Register, 1999, National Primary Drinking WaterRegulations; Radon-222: Federal register, v. 64, no. 211,p. 59245–59294.Hem, J.D., 1985, Study and interpretation of the chemicalcharacteristics of natural water (3d ed.): U.S. GeologicalSurvey Water-Supply Paper 2254, 264 p.Kargbo, D.M., Wilhelm, R.G., and Campbell, D.J., 2010, Natu-ral gas plays in the Marcellus shale—Challenges and poten-tial opportunities: Environmental Science and Technology,v 44, p. 5679–5684.Kerr, R.A., 2010, Natural gas from shale bursts onto the scene:Science, v. 328, p. 1624–1626.LaMotte, A.E., 2008, National Land Cover Database 2001 Tile2, northeast United States: U.S. Geological Survey digitaldata, accessed July 5, 2012, at http://water.usgs.gov/lookup/getspatial?nlcd01_2.Miles, C.E., and Whitfield, T.G., comps., 2001, Bedrock geol-ogy of Pennsylvania: Pennsylvania Geological Survey,4th ser., digital dataset, scale 1:250,000.Pennsylvania Department of Conservation and NaturalResources, 2010, DCNR State Forest Lands 2010: Bureauof Forestry, digital dataset, accessed on November 7,2012, at http://www.pasda.psu.edu/uci/MetadataDisplay.aspx?entry=PASDA&file=dcnr_stateforestlands_2010.xml&dataset=263.Pennsylvania Department of Conservation and NaturalResources, 2011, DCNR State Parks 201109: Bureau ofState Parks, digital dataset, accessed on November 7,2012, at http://www.pasda.psu.edu/uci/MetadataDisplay.aspx?entry=PASDA&file=DCNR_StateParks201109.xml&dataset=114.Pennsylvania Department of Environmental Protection, 2012a,Year to date permits issued by well type, accessed Decem-ber 5, 2012, at http://www.depreportingservices.state.pa.us/ReportServer/Pages/ReportViewer.aspx?/Oil_Gas/Permits_Issued_Count_by_Well_Type_YTD.Pennsylvania Department of Environmental Protection, 2012b,Wells drilled by county, accessed December 5, 2012, at http://www.depreportingservices.state.pa.us/ReportServer/Pages/ReportViewer.aspx?/Oil_Gas/Wells_Drilled_By_County.Pennsylvania Department of Transportation, 2009a, PennDOT- Pennsylvania municipality boundaries 2009: Pennsylva-nia Department of Transportation, Bureau of Planning andResearch, Cartographic Information Division, digital dataset,accessed on October 9, 2012, at http://www.pasda.psu.edu/uci/MetadataDisplay.aspx?entry=PASDA&file=PaMunicipalities2009_01.xml&dataset=41.Pennsylvania Department of Transportation, 2009b, PennDOT- Pennsylvania county boundaries 2009: PennsylvaniaDepartment of Transportation, Bureau of Planning andResearch, Cartographic Information Division, digital data-set, accessed on October 9, 2012, at http://www.pasda.psu.edu/uci/MetadataDisplay.aspx?entry=PASDA&file=PaCounty2009_01.xml&dataset=24.
  35. 35. References Cited  27Pennsylvania Game Commission, 2011, PGC State GameLands 201108: digital dataset accessed November 7,2012, at http://www.pasda.psu.edu/uci/MetadataDisplay.aspx?entry=PASDA&file=PGC_StateGameland201108.xml&dataset=86.Pennsylvania Geological Survey, 2012, Pennsylvania ground-water information system (PAGWIS) documentation,accessed October 3, 2012, at http://www.dcnr.state.pa.us/topogeo/groundwater/PaGWIS/help.aspx.PRISM Group at Oregon State University, 2013, Pre-cipitation and average minimum and maximum tem-perature, 1971–2000: PRISM Group at Oregon StateUniversity digital data, accessed February 15, 2013,at http://www.prism.oregonstate.edu/products/matrix.phtml?vartype=tmax&view=data.Sevon, W.D., 2000, Physiographic provinces of Pennsylvania:Pennsylvania Geological Survey, 4th ser., Map 13, 1 sheet.Schoell, M., 1980, The hydrogen and carbon isotopic com-position of methane from natural gases of various origins:Geochimica et Cosmochimica Acta, v. 44, p. 649–661.Sullivan County Planning and Economic Development Office,2010, Sullivan County comprehensive plan: SullivanCounty Planning and Economic Development Office, 175 p.Taylor, L.E., Werkheiser, W.H., and Kriz, M.L., 1983, Ground-water resources of the West Branch Susquehanna RiverBasin, Pennsylvania: Pennsylvania Geological Survey, 4thser., Water Resource Report 56, 143 p.U.S. Census Bureau, 2013, 2010 census interactive populationsearch, accessed January 28, 2013, at http://www.census.gov/2010census/popmap/ipmtext.php?fl=42.U.S. Environmental Protection Agency, 2006, Drinking waterstandards and health advisories: U.S. Environmental Protec-tion Agency EPA 822–R–06–013, 12 p.U.S. Environmental Protection Agency, 2012, Drinkingwater contaminants—National primary drinking waterregulations: U.S. Environmental Protection Agency,accessed December 5, 2012, at http://water.epa.gov/drink/contaminants/index.cfm.U.S. Environmental Protection Agency, 2013a, Hydraulic frac-turing, accessed February 15, 2013, at http://water.epa.gov/type/groundwater/uic/class2/hydraulicfracturing/.U.S. Environmental Protection Agency, 2013b, Basic informa-tion about radionuclides in drinking water: U.S. Environ-mental Protection Agency, accessed March, 20, 2013, athttp://water.epa.gov/drink/contaminants/basicinformation/radionuclides.cfm.U.S. Geological Survey, 2009, 1-Arc second National Eleva-tion Dataset: U.S. Geological Survey, SDE raster digitaldata, accessed February 15, 2013, at http://nationalmap.gov/viewer.html.U.S. Geological Survey, 2012a, National Water Quality Labo-ratory: U.S. Geological Survey, accessed December 5, 2012,at http://nwql.usgs.gov/.U.S. Geological Survey, 2012b, Analytical procedures fordissolved gas: U.S. Geological Survey, accessed Decem-ber 5, 2012, http://water.usgs.gov/lab/dissolved-gas/lab/analytical_procedures/.U.S. Geological Survey, 2012c, USGS water data for Pennsyl-vania: U.S. Geological Survey, accessed December 5, 2012,at http://waterdata.usgs.gov/pa/nwis/nwis.U.S. Geological Survey, variously dated, National field man-ual for the collection of water-quality data: U.S. GeologicalSurvey Techniques of Water-Resources Investigations, book9, chap. A1–A9, accessed December 5, 2012, at http://pubs.water.usgs.gov/twri9A/.
  36. 36. For additional information:DirectorU.S. Geological SurveyPennsylvania Water Science Center215 Limekiln RoadNew Cumberland, PA 17070http://pa.water.usgs.gov/Document prepared by the West Trenton Publishing Service Center
  37. 37. Sloto—BaselineGroundwaterQualityfrom20DomesticWellsinSullivanCounty,Pennsylvania,2012—ScientificInvestigationsReport2013–5085Sloto—BaselineGroundwaterQualityfrom20DomesticWellsinSullivanCounty,Pennsylvania,2012—ScientificInvestigationsReport2013–5085

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