Leaching behaviour of chlorpyriphos and cypermethrin in sandy loam soil

The mobility of chlorpyriphos and cypermethrin in sandy loam soil was studied in soil columns under laboratory conditions at two application rates, 25 and 50 μg, with simulated rainfall of 300 mm. Residues of chlorpyriphos and cypermethrin in soil and leachate were estimated by gas-liquid chromatography and confirmed by gas chromatography-mass spectrometry. Though maximum concentration of both the insecticides was found in the top 10-cm layer, chlorpyriphos was found distributed in the soil up to a depth of 35 cm and cypermethrin remained up to 15 cm. Results indicated the low mobility of both the insecticides under saturated moisture condition and hence may not contaminate ground water. No residues of any insecticide were detected in the leachate fractions.