title: 4 Years after the Deepwater Horizon Spill: Molecular Transformation of Macondo Well Oil in Louisiana Salt Marsh Sediments Revealed by FT-ICR Mass Spectrometry.
abstract: Gulf of Mexico saltmarsh sediments were heavily impacted by Macondo well oil (MWO) released from the 2010 Deepwater Horizon (DWH) oil spill. Detailed molecular-level characterization of sediment extracts collected over 48 months post-spill highlights the chemical complexity of highly polar, oxygen-containing compounds that remain environmentally persistent. Electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), combined with chromatographic prefractionation, correlates bulk chemical properties to elemental compositions of oil-transformation products as a function of time. Carboxylic acid incorporation into parent MWO hydrocarbons detected in sediment extracts (corrected for mass loss relative to C30 hopane) proceeds with an increase of ∼3-fold in O2 species after 9 months to a maximum of a ∼5.5-fold increase after 36 months, compared to the parent MWO. More importantly, higher-order oxygenated compounds (O4-O6) not detected in the parent MWO increase in relative abundance with time as lower-order oxygenated species are transformed into highly polar, oxygen-containing compounds (Ox, where x > 3). Here, we present the first molecular-level characterization of temporal compositional changes that occur in Deepwater Horizon derived oil contamination deposited in a saltmarsh ecosystem from 9 to 48 months post-spill and identify highly oxidized Macondo well oil compounds that are not detectable by routine gas-chromatography-based techniques.
authors.forename: Huan
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Environmental Sciences, College of the Coast and Environment, Louisiana State University , 1285 Energy, Coast, and Environment Building, Baton Rouge, Louisiana 70803, United States.
authors.forename: Aixin
authors.initials: A
authors.lastname: Hou
authors.forename: Yuri E
authors.initials: YE
authors.lastname: Corilo
authors.affiliation: Department of Oceanography and Coastal Sciences, College of the Coast and Environment, Louisiana State University , 1002-Y Energy, Coast, and Environment Building, Baton Rouge, Louisiana 70803, United States.
authors.forename: Qianxin
authors.initials: Q
authors.lastname: Lin
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Oceanography and Coastal Sciences, College of the Coast and Environment, Louisiana State University , 1002-Y Energy, Coast, and Environment Building, Baton Rouge, Louisiana 70803, United States.
authors.forename: Irving A
authors.initials: IA
authors.lastname: Mendelssohn
authors.affiliation: Department of Environmental Sciences, College of the Coast and Environment, Louisiana State University , 1285 Energy, Coast, and Environment Building, Baton Rouge, Louisiana 70803, United States.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Rodgers
authors.forename: Amy M
authors.initials: AM
authors.lastname: McKenna
mesh_terms: D006838:Hydrocarbons; D013058:Mass Spectrometry; D059392:Petroleum Pollution; D012965:Sodium Chloride; D053833:Wetlands
chemical_list: D006838:Hydrocarbons; D012965:Sodium Chloride