Residue and Dietary Intake Risk Assessment of Fenpropathrin and Fenvalerate in Chinese kale

Purpose The aim of this study was to investigate the residue dissipation of fenpropathrin and fenvalerate in Chinese kale and soil under open field conditions.

Method The methods for determination of fenpropathrin and fenvalerate were developed and validated using GC-ECD, based on which, the dynamics of both two pesticides were investigated via field trials.

Results The dissipation trends of fenpropathrin and fenvalerate in Chinese kale and soil were fitted to the first order kinetics with half-life of 0.72-1.6 d and 1.2-4.6 d in Chinese kale, and of 7.2-8.2 d and 6.1-23.4 d in soil, respectively, both of which belonged to the pesticide that was easy to be degraded. According to the terminal residue results, the fenpropathrin EC and fenvalerate EC were applied at a recommended dosage and at 1.5 times the recommended dosage for 3 to 4 times, the residues of fenpropathrin in Chinese kale was lower than 1.54 mg/kg with a risk quotient (RQ) of 0.407 on 5 d after the last application. The residues of fenvalerate was lower than 1.14 mg/kg with a RQ of 0.452 on 7 d after the last application, indicating that the risk was not significant.

Conclusion Based on the results of risk assessment, it is recommended that 20% fenpropathrin EC used at a dose of 90 g a.i/hm² and 20% fenvalerate EC used at a dose 120 g a.i/hm² in Chinese kale, the application time do not exceed 3 times, and the pre-harvest intervals are 5 d and 7 d for fenpropathrin and fenvalerate, respectively.