Comparison of fipronil sources in North Carolina surface water and identification of a novel fipronil transformation product in recycled wastewater Rebecca L. McMahen a , Mark J. Strynar b, ⁎, Larry McMillan c , Eugene DeRose d , Andrew B. Lindstrom b a United States Environmental Protection Agency, National Exposure Research Laboratory, 109 TW Alexander Dr., Durham, North Carolina 27705, United States b United States Environmental Protection Agency, National Exposure Research Laboratory, 109 TW Alexander Dr., Durham, North Carolina 27705, United States c National Caucus and Center on Black Aged Employee, U.S. Environmental Protection Agency, National Exposure Research Laboratory, 109 TW Alexander Dr., Durham, North Carolina 27705, United States d National Institute for Environmental Health Sciences, Nuclear Magnetic Resonance Facility, 111 TW Alexander Dr., Durham, North Carolina 27713, United States HIGHLIGHTS • The most important sources of fipronil in the environment have yet to be determined. • Sampling was conducted to learn more about the origins of fipronil in surface water. • High resolution mass spec analysis indicated that fipronil was routinely present. • Concentrations were substantially elevated near wastewater treatment plant outfalls. • In recycled water fipronil compounds are oxidized to a novel species. GRAPHICAL ABSTRACT abstract article info Article history: Received 15 April 2016 Received in revised form 12 May 2016 Accepted 13 May 2016 Available online xxxx Editor: Adrian Covaci Fipronil is a phenylpyrazole insecticide that is widely used in residential and agricultural settings to control ants, roaches, termites, and other pests. Fipronil and its transformation products have been found in a variety of environmental matrices, but the source[s] which makes the greatest contribution to fipronil in surface water has yet to be determined. A sampling effort designed to prioritize known fipronil inputs (golf courses, residential areas, biosolids application sites and wastewater facilities) was conducted in North Carolina to learn more about the origins of fipronil in surface water. High resolution mass spectrometry (HRMS) analysis indicated that fipronil and its known derivatives were routinely present in all samples, but concentrations were substantially elevated near wastewater treatment plant outfalls (range 10–500 ng/L combined), suggesting that they predominate as environmental sources. Corresponding recycled wastewater samples, which were treated with NaOCl for disin- fection, showed disappearance of fipronil and all known degradates. HRMS and nuclear magnetic resonance Keywords: Fipronil Source evaluation Science of the Total Environment xxx (2016) xxx–xxx Abbreviations: ACN, acetonitrile; DCM, dichloromethane; DI, deionized; EPA, environmental protection agency; FSC, fipronil sulfone chloramine; GABA, gamma-Aminobutyric acid; gHSQCAD, gradient heteronuclear single quantum coherence; HDPE, high-density polyethylene; HLB, hydrophilic-lipophilic balance; HPLC, high performance liquid chromatography; HRMS, high resolution mass spectrometry; LCL, lowest calibration level; LC/TOF, liquid chromatography time-of-flight mass spectrometry; MeOH, methanol; MgSO 4 , magnesium sulfate; NaOCl, sodium hypochlorite; NMR, nuclear magnetic resonance; TOF-MS, time-of-flight mass spectrometry; US, United States; WWTP, wastewater treatment plant. ⁎ Corresponding author. E-mail address: strynar.mark@epa.gov (M.J. Strynar). STOTEN-19989; No of Pages 8 http://dx.doi.org/10.1016/j.scitotenv.2016.05.085 0048-9697/Published by Elsevier B.V. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv Please cite this article as: McMahen, R.L., et al., Comparison of fipronil sources in North Carolina surface water and identification of a novel fipronil transformation product in re..., Sci Total Environ (2016), http://dx.doi.org/10.1016/j.scitotenv.2016.05.085