HPLC-PDA Determination of Chlorpyrifos and Glyphosate Residues in Mango Orchard Soil and their Subsequent Uptake to Mango Fruit

Chlorpyrifos and glyphosate are used to control mango mealybug and weeds respectively in mango ecosystem. Chlorpyrifos (2.5 and 5.0 mL L⁻¹ of water) and glyphosate (8.0 and 16.0 mL L⁻¹ of water) were applied to mango (cv. Dashehari) orchard soil to study their dissipation in soil and subsequent uptake in mango fruit using HPLC-PDA. Chlorpyrifos and glyphosate applied at standard and double doses, respectively dissipated from 5.05 and 8.30 mg kg⁻¹, and 3.37 and 6.12 mg kg⁻¹ after 2 h of soil application to 0.75 and 1.07 mg kg⁻¹, and 0.61 and 1.04 mg kg⁻¹ after 50 and 30 d of application. Residue of glyphosate was below detectable limit in soil beyond 30 d of application. The residual half-lives of chlorpyrifos and glyphosate in soil were 17–18 and 12–13 d from the standard and double doses, respectively. The rate of dissipation followed first-order exponential kinetics in soil for both the concentrations. Residues of either pesticide were below detectable limit in mature fruits at harvest. Hence, both the pesticides can be considered safe for their respective uses in mango ecosystem.