title: Evaluation of methane sources in groundwater in northeastern Pennsylvania.
abstract: Testing of 1701 water wells in northeastern Pennsylvania shows that methane is ubiquitous in groundwater, with higher concentrations observed in valleys vs. upland areas and in association with calcium-sodium-bicarbonate, sodium-bicarbonate, and sodium-chloride rich waters--indicating that, on a regional scale, methane concentrations are best correlated to topographic and hydrogeologic features, rather than shale-gas extraction. In addition, our assessment of isotopic and molecular analyses of hydrocarbon gases in the Dimock Township suggest that gases present in local water wells are most consistent with Middle and Upper Devonian gases sampled in the annular spaces of local gas wells, as opposed to Marcellus Production gas. Combined, these findings suggest that the methane concentrations in Susquehanna County water wells can be explained without the migration of Marcellus shale gas through fractures, an observation that has important implications for understanding the nature of risks associated with shale-gas extraction.
authors.affiliation: GSI Environmental Inc, Houston, TX 77373, USA. lmolofsky@gsi-net.com
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Molofsky
authors.forename: John A
authors.initials: JA
authors.lastname: Connor
authors.forename: Albert S
authors.initials: AS
authors.lastname: Wylie
authors.forename: Tom
authors.initials: T
authors.lastname: Wagner
authors.forename: Shahla K
authors.initials: SK
authors.lastname: Farhat
mesh_terms: D002247:Carbon Isotopes; D004784:Environmental Monitoring; D005844:Geology; D060587:Groundwater / Q000032:analysis* / Q000737:chemistry*; D006838:Hydrocarbons / Q000032:analysis; D007554:Isotopes / Q000032:analysis; D008697:Methane / Q000032:analysis*; D061329:Oil and Gas Fields; D010414:Pennsylvania; D060753:Water Quality; D014881:Water Supply / Q000032:analysis; D060986:Water Wells
chemical_list: D002247:Carbon Isotopes; D006838:Hydrocarbons; D007554:Isotopes; D008697:Methane
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