Assessing the endosulfan contamination in an unconfined aquifer.

Groundwater samples were analyzed in order to elucidate the fate of endosulfan in the soil and its release mechanism into water of an unconfined aquifer. Residual alfa endosulfan was determined in all the wells; however, beta endosulfan was below 0.001 μg/L. Maximum adsorption rates of alfa and beta endosulfan were 91%-86% on the topsoil; 87%-91% on the subsoil, respectively. About 13%-23% desorption rate on the topsoil and subsoil exhibited the probability of endosulfan movement in the soil. The study showed that a hydrophobic-moderately persistent pesticide can reach to groundwater despite the high clay content of soil.