Kinetics of extractable residue, bound residue and mineralization of a novel herbicide, ZJ0273, in aerobic soils

ZJ0273, propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate, is a broad-spectrum herbicide being marketed for use on rape crops. However, environmental behavior and fate of ZJ0273 remained poorly understood. In this study, we used ZJ0273 labelled with C-14 on the C ring to understand the transformation of ZJ0273 in aerobic soils. Results showed a first-order dissipation pattern for the parent compound, with half-lives ranging from 17.2 to 53.7 d, suggesting a short to moderate persistence. The dissipation of the parent molecule was accompanied by formation of bound residues and mineralization. The transformation of ZJ0273 appeared to decrease with decreasing soil pH and organic matter content. Differences were often observed in the formation of bound residues, and mineralization among different soils. After 100 d of incubation, the total bound residue accounted for 17.4-28.8% of the total applied amount in the three soils, while cumulative mineralization to CO2 reached 1.2% for an acidic soil, 7.7% for neutral and 9.9% for alkaline soil, suggesting that the herbicide in the neutral and alkaline soils met the non-accumulative criteria as stated in the directives by the Commission of the European Communities. (C) 2009 Elsevier Ltd. All rights reserved.