Dissipation rates and residue levels of diflubenzuron and difenoconazole on peaches and dietary risk assessment

Abstract

The dissipation kinetics, residue levels, and potential risks of diflubenzuron and difenoconazole on peaches were investigated under open field conditions. Two years of field trials were carried out in Shanghai, China, and the half-lives of diflubenzuron and difenoconazole on peaches ranged from 4.4 to 25d. Their terminal residue concentrations on peaches were 0.022–5.7 mg/kg after three of the tested sampling intervals. Based on the maximum residue levels (MRLs) of difenoconazole on peaches, a preharvest interval (PHI) of 14 d was proposed. A PHI of 10 d was proposed for diflubenzuron after a dietary safety assessment. During the safety assessment, the hazard quotient (HQ) and risk quotient (RQ) on peaches were determined. The results showed that the HQs (3.6–8.3%) and RQs(51–55%) of diflubenzuron were acceptable, proving that diflubenzuron poses no potential health risks. For difenoconazole, the HQs (0.027–0.071%) were satisfactory, but the RQs (115–116%) exceeded 100%, which indicated potential risk.