Adsorption,Desorption and Mobility of Four Commonly Used Pesticides in Malaysian Agricultural Soils

Working with Malaysian agricultural soils, high Freundlich adsorption distribution coefficients (K_ads(f)) were observed for paraquat (28·7 and 1419) and glyphosate (83·8 and 417) and lower values for 2,4-D (0·57 and 5·26) and lindane (2·65 and 14·1) in a sandy loam and a muck soil, respectively. Desorption of 2,4-D and lindane from the muck soil occurred. The adsorption of the pesticides was not affected by temperature (20°C/30°C), pH or addition of the pesticides as a mixture. Leaching of 2,4-D and lindane was evident under a high water influx (200 mm). Comparable results in the leaching of 2,4-D were observed between laboratory studies and a VARLEACH model prediction. © 1997 SCI.