Pesticide adsorption in a soil-water system in the presence of surfactants

The impact of anionic, cationic, and nonionic surfactants on the adsorption of four pesticides on a sandy loam soil was investigated. The pesticides were diazinon, acephate, atrazine, and ethofumesate. Three surfactant concentrations were examined: the critical micellar concentration, and 20-fold higher and ten-fold lower. Results indicated that, in all cases, the adsorption data could be described by the empirical Freundlich adsorption equation. Adsorption was found to depend on the degree of pesticide hydrophobicity and the surfactant concentration used. The effects of each surfactant type on pesticide adsorption are discussed separately.