title: Identifying chemicals of concern in hydraulic fracturing fluids used for oil production.
abstract: Chemical additives used for hydraulic fracturing and matrix acidizing of oil reservoirs were reviewed and priority chemicals of concern needing further environmental risk assessment, treatment demonstration, or evaluation of occupational hazards were identified. We evaluated chemical additives used for well stimulation in California, the third largest oil producing state in the USA, by the mass and frequency of use, as well as toxicity. The most frequently used chemical additives in oil development were gelling agents, cross-linkers, breakers, clay control agents, iron and scale control agents, corrosion inhibitors, biocides, and various impurities and product stabilizers used as part of commercial mixtures. Hydrochloric and hydrofluoric acids, used for matrix acidizing and other purposes, were reported infrequently. A large number and mass of solvents and surface active agents were used, including quaternary ammonia compounds (QACs) and nonionic surfactants. Acute toxicity was evaluated and many chemicals with low hazard to mammals were identified as potentially hazardous to aquatic environments. Based on an analysis of quantities used, toxicity, and lack of adequate hazard evaluation, QACs, biocides, and corrosion inhibitors were identified as priority chemicals of concern that deserve further investigation.
authors.affiliation: Earth & Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA; Ecological Engineering Research Program, School of Engineering & Computer Science, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA. Electronic address: wstringfellow@lbl.gov.
authors.forename: William T
authors.initials: WT
authors.lastname: Stringfellow
authors.affiliation: Ecological Engineering Research Program, School of Engineering & Computer Science, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA.
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Camarillo
authors.affiliation: Ecological Engineering Research Program, School of Engineering & Computer Science, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA.
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Domen
authors.affiliation: Ecological Engineering Research Program, School of Engineering & Computer Science, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA.
authors.forename: Whitney L
authors.initials: WL
authors.lastname: Sandelin
authors.affiliation: Earth & Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
authors.forename: Charuleka
authors.initials: C
authors.lastname: Varadharajan
authors.affiliation: Earth & Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
authors.forename: Preston D
authors.initials: PD
authors.lastname: Jordan
authors.affiliation: Earth & Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Reagan
authors.affiliation: Pacific Institute, 654 13th Street, Preservation Park, Oakland, CA 94612, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Cooley
authors.affiliation: Pacific Institute, 654 13th Street, Preservation Park, Oakland, CA 94612, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Heberger
authors.affiliation: Earth & Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
authors.forename: Jens T
authors.initials: JT
authors.lastname: Birkholzer
mesh_terms: D000818:Animals; D002140:California; D004202:Disinfectants; D004784:Environmental Monitoring; D019652:Extraction and Processing Industry; D006801:Humans; D000067071:Hydraulic Fracking; D061329:Oil and Gas Fields; D018570:Risk Assessment
chemical_list: D004202:Disinfectants
keywords: Biocides; Corrosion inhibitors; Hydraulic fracturing; Oil production; Produced water; Well stimulation