Dissipation and Decontamination of Some Pesticides in/on Okra

Dissipation and decontamination of deltamethrin, alphamethrin, deltamethrin (in combination), triazophos, ethion, cypermethrin and profenophos residues were studied in/on okra fruits at middle Gujarat region, India. The samples were procured up to 7 d after application of pesticides by Knapsack sprayer. The average initial deposit of deltamethrin, alphamethrin, deltamethrin in combination, triazophos, ethion, cypermethrin and profenophos was 0.152, 0.136, 0.025, 0.543, 0.254, 0.172 and 4.519 mg kg⁻¹, respectively which dissipated to 0.025 (83.55%), 0.023 (83.09%), 0.010 (60.00%), 0.015 (0.015%), 0.013 (94.88%), 0.020 (88.37%) and 0.508 (88.76%) mg kg⁻¹ on 5^th and 7^th d. The half-life values for respective pesticides were 2.09, 2.09, 2.61, 1.68, 1.27, 2.59 and 1.88 d, respectively. Effect of decontamination processing viz. rubbing with wet cloth, dipping in normal water for 10 min, washing with normal water for 10 min, washing with 2% brine solution for 10 min and cooking was studied to dislodge pesticide residues on okra. Dislodging of various pesticide residues were observed more in cooking (46.62 to 95.10%), followed by washing with 2% brine solution (31.58 to 94.67%), washing with normal water (26.32 to 93.72%), dipping in normal water (9.02 to 90.80%) and rubbing with wet cloth (0.93 to 32.69%) after 1st d of the treatment. Reduction of residues after rubbing with wet cloth was minimal.