title: Halogenated Organic Compounds Identified in Hydraulic Fracturing Wastewaters Using Ultrahigh Resolution Mass Spectrometry.
abstract: Large volumes of water return to the surface following hydraulic fracturing of deep shale formations to retrieve oil and natural gas. Current understanding of the specific organic constituents in these hydraulic fracturing wastewaters is limited to hydrocarbons and a fraction of known chemical additives. In this study, we analyzed hydraulic fracturing wastewater samples using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) as a nontargeted technique to assign unambiguous molecular formulas to singly charged molecular ions. Halogenated molecular formulas were identified and confirmed using isotopic simulation and MS-MS fragmentation spectra. The abundance of halogenated organic compounds in flowback fluids rather than older wastewaters suggested that the observed molecular ions might have been related to hydraulic fracturing additives and related subsurface reactions, such as through the reaction of shale-extracted chloride, bromide, and iodide with strong oxidant additives (e.g., hypochlorite, persulfate, hydrogen peroxide) and subsequently with diverse dissolved organic matter. Some molecular ions matched the exact masses of known disinfection byproducts including diiodoacetic acid, dibromobenzoic acid, and diiodobenzoic acid. The identified halogenated organic compounds, particularly iodinated organic molecules, are absent from inland natural systems and these compounds could therefore play an important role as environmental tracers.
authors.affiliation: University of Maryland Center for Environmental Science , Chesapeake Biological Laboratory, Solomons, Maryland United States.
authors.forename: Jenna L
authors.identifier: http://orcid.org/0000-0002-1343-5375
authors.initials: JL
authors.lastname: Luek
authors.affiliation: Helmholtz Zentrum Muenchen , Research Unit Analytical BioGeoChemistry, Neuherberg, Germany.|Technische Universität München , Chair of Analytical Food Chemistry, Freising-Weihenstephan, Germany.
authors.forename: Philippe
authors.initials: P
authors.lastname: Schmitt-Kopplin
authors.affiliation: The Ohio State University , Department of Civil, Environmental and Geodetic Engineering, Columbus, Ohio United States.
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Mouser
authors.affiliation: Univeristy of South Carolina , Department of Chemistry and Biochemistry, Columbia, South Carolina United States.
authors.forename: William Tyler
authors.initials: WT
authors.lastname: Petty
authors.affiliation: Univeristy of South Carolina , Department of Chemistry and Biochemistry, Columbia, South Carolina United States.
authors.forename: Susan D
authors.initials: SD
authors.lastname: Richardson
authors.affiliation: University of Maryland Center for Environmental Science , Chesapeake Biological Laboratory, Solomons, Maryland United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Gonsior
mesh_terms: D000067071:Hydraulic Fracking; D013058:Mass Spectrometry; D059206:Natural Gas; D009930:Organic Chemicals / Q000032:analysis*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical
chemical_list: D059206:Natural Gas; D009930:Organic Chemicals; D062065:Wastewater; D014874:Water Pollutants, Chemical