Journal of Food Safety and Quality

Objective To evaluate the degradation dynamics of the combined use of bifenazate and etoxazole on Vigna unguiculata and assess the dietary exposure risks for different population groups. Methods Bifenazate (sum of bifenazate and bifenazate-diazene) in samples of Vigna unguiculata collected from eight regions of China were detected by liquid chromatography-tandem mass spectrometry. Dietary exposure risk assessment was conducted based on the test results , dietary consumption data and body weight data of different population groups in China. Results The dissipation behaviors of bifenazate in Vigna unguiculata from Shandong, Anhui, Hunan and Guangxi all did not follow first-order kinetics. The dissipation behaviors of etoxazole in Vigna unguiculata from Shandong, Anhui, Hunan, and Guangxi followed first-order kinetics, and their half-lives were 1.93–2.54 d. Using a suspension concentrate containing 45% bifenazate and etoxazole with 8 mL formulation per mu (Chinese acre) to control red mites on Vigna unguiculata, spraying once, at the harvest interval of 10 d, terminal concentrations of bifenazate and etoxazole in Vigna unguiculata were <0.0100 mg/kg and <0.0020–0.0042 mg/kg, respectively. The contribution rate of the long-term dietary exposure risk of these 2 kinds of pesticides were all lower than 100% for different population groups, indicating that there was no unacceptable risk. Conclusion 45% bifenazate·etoxazole suspension concentrate is applied at a dosage of 8 mL per mu for controlling spider mites on Vigna unguiculata, with one spray application and a recommended pre-harvest interval of 10 days.

Vigna unguiculata; mixture application; pesticide residue; short-term dietary exposure; long-term dietary exposure