Dissipation profile of sulfoxaflor on squash under Egyptian field conditions: a prelude to risk assessment

Abstract

The neonicotinoid insecticide sulfoxaflor is widely used in Egypt. This work assessed the safety of using sulfoxaflor in squash to consumers, along with the residue behaviour. Supervised field trials were conducted to investigate the dynamics and terminal residues of sulfoxaflor in squash under Egyptian field conditions for several agricultural practices, including worst-case scenarios. A QuEChERS-based protocol coupled with LC-MS/MS was employed to measure residues in squash fruits; the limit of quantitation was successfully validated at 0.01 mg/kg. Sulfoxaflor residues reduce in squash fruits via a first-order decay process, with a calculated half–life (t1/2) of 6.13 days and significant degradation (88.5%) after 14 days. During harvest, the terminal residues of sulfoxaflor were ranged from 0.365 to 1.611 mg/kg and from 0.576 to 1.865 mg/kg on sampling days of 3, 7 and 14 days when applied 2-3 times at single or double recommended dose, respectively. A consumer risk assessment was performed employing the FAO/WHO approach; the risk quotients (RQs) were ≤0.0102, and hence; no significant health risks associated with consumption of squash treated with sulfoxaflor were identified.