Persistence and Risk Assessment of Quinalphos in Some Vegetables

The dissipation of quinalphos was studied on cabbage, cauliflower and potato from treatment @ 500 and 1000 g a.i. ha⁻¹; on onion, from treatment @ 300 and 600 g a.i.ha⁻¹. The initial deposits of quinalphos were found to be 0.740 and 1.250 mg kg⁻¹ in cabbage head, 0.475 and 0.888 mg kg⁻¹ in cauliflower curds and 1.058 and 1.359 mg kg⁻¹ in green/immature onion at the lower and higher doses, respectively. Initial deposits dissipated to half in 1.802.20, 1.21–1.26 and 2.46–3.00 d from cabbage, cauliflower and onion, respectively, at both doses. The residues persisted for 3 and 5 d on cauliflower and cabbage, respectively, at lower dose and for 5 d at higher dose. In immature onion, quinalphos persisted up to 7 d at lower dose and 10 d at higher dose. The residues were below detection limit (0.05 mg kg⁻¹) on potato tubers at 0 d sampling, although its cropped soil contained detectable residues. Average recoveries of quinalphos from different crop samples spiked at different levels (0.05–1.50 mg kg⁻¹) ranged from 94.00–96.00, 87.20–94.20, 90.44–94.00 and 85.70–100.00% for cabbage, cauliflower, onion and potato, respectively. Dietary risk assessment of quinalphos revealed no appreciable risk arising through consumption of treated cabbage, cauliflower, onion and potato.