HPLC-PDA determination of chlorpyrifos and glyphosate residues in mango orchard soil and their subsequent uptake to mango fruit.

Abstract

Chlorpyrifos is generally used to control mango mealybug and glyphosate is used to control various weeds in mango ecosystem. Chlorpyrifos (2.5 and 5.0 ml/l of water) and glyphosate (8.0 and 16.0 ml/l of water) was applied to mango (cv. Dashehari) orchard soil to study their dissipation pattern in soil and subsequent uptake in mango fruit using HPLC-PDA. Chlorpyrifos and glyphosate dissipated from 5.05 and 8.30 mg/kg, and 3.37 and 6.12 mg/kg after 2 h of soil application to 0.75 and 1.07 mg/kg, and 0.61 and 1.04 mg/kg after 50 and 30 days of application at single and double doses, respectively. No residue of glyphosate was detected in soil beyond 30 days of application. The residual half-life values for chlorpyrifos and glyphosate in soil were calculated as 17-18 days and 12-13 days from single and double doses, respectively. The rate of dissipation followed first-order exponential kinetics in soil for both the concentrations. No residue of either pesticide was detected in mature fruits after harvest. Hence, both the pesticides can be considered safe for their respective use in mango ecosystem.