Metabolism of insecticide bistrifluron in soil

Abstract

Bistrifluron[N-2,6-Difluorobenzoyl-N-chlorois(3,5trifluoromethyl) Phenyl)urea] is a novel broad spectrum insecticide which developed by Dongbu-hannong Chemical Co. (Korea). To elucidate metabolic fate of bistrifluron, aerobic and aerobic flooded soil metabolism were investigated with [14C]bistrifluron. The metabolic studies were conducted for 120 days at a concentration of 0.28 μg/g on loamy soil in the dark a 22 ±1 oC with flow through system. The half-life of bistrifluron were approximately 110 days for aerobic condition and 48 days for aerobic flooded condition, respectively. Under aerobic condition, the metabolites were not observed while the evolved [14C]carbon dioxide accounted for up to 35.5% of applied radiocarbon at 120 DAT. Non-extractable bound residue accumulated up to 8.4% of that applied at 120 DAT under same condition. Under aerobic flooded condition, [14C]carbon dioxide was not observed and one metabolite CBU (2-chloro-3,5-bis-trifluroromethylphenyl)- urea) was observed and identified through LC/MS and NMR after isolation. It showed maximum concentration of 80.8% of applied radiocarbon at 120 DAT. The non-extractable radioactivity levels did not increase as the soil aged, accounting for 1.2% of applied radiocarbon at 120 DAT. The volatiles were not detected during both of the studies. The average material balance over the time course of the study was 93.2-105.9% of applied radiocarbon in both conditions.