Residual behavior, dissipation kinetics and decontamination of tolfenpyrad residue in cabbage and soil

Field trials were conducted to assess the effect of tolfenpyrad on consumers by studying the persistence, dissipation kinetics and effect of different household processing methods in the reduction of tolfenpyrad residues in cabbage. The average residues in cabbage heads (2 h after spray) were found to be 1.36, 1.46 and 2.39 mg kg^-1 after two applications at doses of 150, 187.5 and 300 g a.i. ha^-1. The residues dissipated below the LOQ of 0.01 mg kg^-1 after 15, 15 and 20 days of application at the three respective doses. In soil, the residues dissipated below the quantification limit on fifth, seventh and tenth day at three respective doses. Dissipation followed first-order kinetics with half-life (T_1/2) values of 2.11, 2.14, and 1.97 days at 150, 187.5 and 300 g a.i. ha^-1 doses, respectively. Risk assessment studies showed that application at 150 and 300 g a.i. ha^-1 doses using proper agricultural practices resulted in a Hazard Quotient less than 1. Effectiveness of household practices to decontaminate tolfenpyrad residues was assessed and cooking of cabbage proved to be more effective (81.60-85.91 per cent reduction of residues).