title: A reconnaissance analysis of groundwater quality in the Eagle Ford shale region reveals two distinct bromide/chloride populations.
abstract: The extraction of oil and natural gas from unconventional shale formations has prompted a series of investigations to examine the quality of the groundwater in the overlying aquifers. Here we present a reconnaissance analysis of groundwater quality in the Eagle Ford region of southern Texas. These data reveal two distinct sample populations that are differentiable by bromide/chloride ratios. Elevated levels of fluoride, nitrate, sulfate, various metal ions, and the detection of exotic volatile organic compounds highlight a high bromide group of samples, which is geographically clustered, while encompassing multiple hydrogeological strata. Samples with bromide/chloride ratios representative of connate water displayed elevated levels of total organic carbon, while revealing the detection of alcohols and chlorinated compounds. These findings suggest that groundwater quality in the Western Gulf Basin is, for the most part, controlled by a series of natural processes; however, there is also evidence of episodic contamination events potentially attributed to unconventional oil and gas development or other anthropogenic activities. Collectively, this characterization of natural groundwater constituents and exogenous compounds will guide targeted remediation efforts and provides insight for agricultural entities, industrial operators, and rural communities that rely on groundwater in southern Texas.
authors.affiliation: Affiliate of the Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX 76019, United States; Inform Environmental, LLC, Dallas, TX 75206, United States. Electronic address: zac@informenv.com.
authors.forename: Zacariah L
authors.initials: ZL
authors.lastname: Hildenbrand
authors.affiliation: Affiliate of the Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX 76019, United States; Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States.
authors.forename: Doug D
authors.initials: DD
authors.lastname: Carlton
authors.affiliation: Affiliate of the Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX 76019, United States; Department of Biological Sciences, Tarleton State University, Stephenville, TX 76401, United States.
authors.forename: Jesse M
authors.initials: JM
authors.lastname: Meik
authors.affiliation: Inform Environmental, LLC, Dallas, TX 75206, United States.
authors.forename: Josh T
authors.initials: JT
authors.lastname: Taylor
authors.affiliation: Affiliate of the Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX 76019, United States.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Fontenot
authors.affiliation: Affiliate of the Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX 76019, United States.
authors.forename: Jayme L
authors.initials: JL
authors.lastname: Walton
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States.
authors.forename: Drew
authors.initials: D
authors.lastname: Henderson
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Thacker
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Korlie
authors.affiliation: Division of Water, Climate, and Environment, School of Earth Sciences, The Ohio State University, Columbus, OH 43210, United States; Division of Solid Earth Dynamics, School of Earth Sciences, The Ohio State University, Columbus, OH 43210, United States.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Whyte
authors.affiliation: Department of Geography, University of North Texas, Denton, TX 76203, United States.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Hudak
authors.affiliation: Affiliate of the Collaborative Laboratories for Environmental Analysis and Remediation, The University of Texas at Arlington, Arlington, TX 76019, United States; Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, United States. Electronic address: kschug@uta.edu.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Schug
keywords: Eagle Ford; Groundwater; Shale energy extraction