title: Photoinduced oxidation of the insecticide phenothrin on soil surfaces.
abstract: Photodegradation profiles of the pyrethroid insecticide phenothrin on a moistened U.S. soil thin layer was investigated by using its predominant component, the 1R-trans-isomer (I), under continuous exposure to light at >290 nm from a xenon arc lamp. Its degradation was moderately accelerated by irradiation with half-lives of 5.7-5.9 days (dark control 21-24 days), mainly via successive oxidation of the 2-methylprop-1-enyl group and ester cleavage followed by mineralization to carbon dioxide. Spectroscopic and cochromatographic analyses showed that the major degradates were the alcohol and ketone derivatives of I formed via photoinduced oxidation of the 2-methylprop-1-enyl group by singlet oxygen. The photoinduced generation of singlet oxygen in/on the soil surface was confirmed by using chemical trapping reactions together with ESR spectroscopy.
authors.affiliation: Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd., 4-2-1 Takatsukasa, Takarazuka, Hyogo 665-8555, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Andrea
authors.initials: A
authors.lastname: Lopez
authors.forename: Marian
authors.initials: M
authors.lastname: Ponte
authors.forename: Takuo
authors.initials: T
authors.lastname: Fujisawa
authors.forename: Luis O
authors.initials: LO
authors.lastname: Ruzo
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Katagi
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D007306:Insecticides / Q000737:chemistry*; D008027:Light; D010084:Oxidation-Reduction; D010782:Photolysis; D011722:Pyrethrins / Q000737:chemistry*; D012987:Soil / Q000032:analysis* / Q000737:chemistry
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D012987:Soil; C006166:phenothrin