title: Tar balls from Deep Water Horizon oil spill: environmentally persistent free radicals (EPFR) formation during crude weathering.
abstract: Tar balls collected from the Gulf of Mexico shores of Louisiana and Florida after the BP oil spill have shown the presence of electron paramagnetic resonance (EPR) spectra characteristic of organic free radicals as well as transition metal ions, predominantly iron(III) and manganese(II). Two types of organic radicals were distinguished: an asphaltene radical species typically found in crude oil (g = 2.0035) and a new type of radical resulting from the environmental transformations of crude (g = 2.0041-47). Pure asphaltene radicals are resonance stabilized over a polyaromatic structure and are stable in air and unreactive. The new radicals were identified as products of partial oxidation of crude components and result from the interaction of the oxidized aromatics with metal ion centers. These radicals are similar to semiquinone-type, environmentally persistent free radicals (EPFRs) previously observed in combustion-generated particulate and contaminated soils.
authors.affiliation: Chemistry Department, Louisiana State University, 338 Choppin Hall, Baton Rouge, Louisiana 70803, USA.
authors.forename: Lucy W
authors.initials: LW
authors.lastname: Kiruri
authors.forename: Barry
authors.initials: B
authors.lastname: Dellinger
authors.forename: Slawo
authors.initials: S
authors.lastname: Lomnicki
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D004777:Environment; D005609:Free Radicals / Q000737:chemistry*; D060851:Gulf of America; D059392:Petroleum Pollution; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014887:Weather
chemical_list: D005609:Free Radicals; D014874:Water Pollutants, Chemical