Hydrocarbons in upland groundwater, Marcellus Shale Region, Northeastern Pennsylvania and Southern New York, USA

Environmental Science & Technology
By: , and 

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Abstract

Water samples from 50 domestic wells located <1 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. CH4-isotope, predrill CH4-concentration, and other data indicate that one proximal sample (5% of proximal samples) contains thermogenic CH4 (2.6 mg/L) from a relatively shallow source (Catskill/Lock Haven Formations) that appears to have been mobilized by shale-gas production activities. Another proximal sample contains five other volatile hydrocarbons (0.03–0.4 μg/L), including benzene, more hydrocarbons than in any other sample. Modeled groundwater-age distributions, calibrated to 3H, SF6, and 14C concentrations, indicate that water in that sample recharged prior to shale-gas development, suggesting that land-surface releases associated with shale-gas production were not the source of those hydrocarbons, although subsurface leakage from a nearby gas well directly into the groundwater cannot be ruled out. Age distributions in the samples span ∼20 to >10000 years and have implications for relating occurrences of hydrocarbons in groundwater to land-surface releases associated with recent shale-gas production and for the time required to flush contaminants from the system.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Hydrocarbons in upland groundwater, Marcellus Shale Region, Northeastern Pennsylvania and Southern New York, USA
Series title Environmental Science & Technology
DOI 10.1021/acs.est.9b01440
Volume 53
Issue 14
Year Published 2019
Language English
Publisher American Chemical Society
Contributing office(s) Pennsylvania Water Science Center, California Water Science Center, Massachusetts Water Science Center, New England Water Science Center, Southwest Regional Director's Office, National Water Quality Assessment Program, National Water Quality Program, Energy Resources Program, Central Energy Resources Science Center, Crustal Geophysics and Geochemistry Science Center, Colorado Water Science Center
Description 9 p.
First page 8027
Last page 8035
Country United States
State New York, Pennsylvania