title: Decrease of herbicide bromobutide and its debromo metabolite in paddy field soil during 24 weeks after application.
abstract: Variations in concentrations of herbicide bromobutide (RS)-2-bromo-N-(α,α-dimethylbenzyl)-3,3-dimethylbutyramide, and its metabolite bromobutide-debromo, N-(α,α-dimethylbenzyl)-3,3-dimethylbutyramide were investigated in soils from three paddy fields used for rice farming at 24 weeks after application. The bromobutide concentration was maximum within 24 h after application. That of bromobutide-debromo was maximum within 5-7 days of application. Each gradually decreased to below detection limits at 12-22 weeks after application. Bromobutide was detected up to 76-104 days after application in the paddy soils, whereas bromobutide-debromo was detected up to 125 days after application. The bromobutide composition was higher than 90 % within 6 days of application, decreasing to less than 5 % by 125 days of application. The decrease of bromobutide amount in the soil was inferred as the first-order reaction. The bromobutide half-life was calculated as 12-21 days (16 days mean) during 18-104 days following application.
authors.affiliation: Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata, Niigata, 956-8603, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Morohashi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Nagasawa
authors.forename: Nami
authors.initials: N
authors.lastname: Enya
authors.forename: Masaki
authors.initials: M
authors.lastname: Ohno
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Suzuki
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kose
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Kawata
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring; D006207:Half-Life; D006540:Herbicides / Q000032:analysis*; D006842:Hydrocarbons, Brominated / Q000032:analysis*; D012275:Oryza; D012987:Soil / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D006540:Herbicides; D006842:Hydrocarbons, Brominated; D012987:Soil; D014874:Water Pollutants, Chemical; C572217:bromobutide