SORPTION-DESORPTION OF METHYL PARATHION, FENITROTHION AND CARBOFURAN IN SOILS

Sorption-desorption of methyl parathion [0, 0-dimethyl 0-(p-nitrophenyl) phosphorothioate ], fenitrothion [0,0-diethyl 0-(3-methyl-4-nitrophenyl) phosphorothioate] and carbofuran (2,3-dihydro-2, 2-dimethyl-7-benzofuranyl N-methylcarbamate) in four soils was studied. Organic matter was the most important single factor affecting the sorption-desorption of all the three insecticides. Freundlich K and specific organic sorption (Kom) of the three insecticides in a given soil distinctly varied, apparently due to the differences in their octanol-water partition coefficient (Kow). Carbofuran with lowest Kow among the three insecticides was sorbed least. All the three insecticides desorbed less with increasing organic matter content of the soil.