Natural attenuation of a low mobility chlorinated insecticide in low‐level and high‐level contaminated soil: A feasibility study

Abstract

AbstractEndosulfan is an economically important insecticide and widespread environmental pollutant, originating from a wide range of agricultural activities. The major implication from the feasibility study described was that endosulfan I can be remediated by natural attenuation processes in cotton‐farming soil, in which concentrations were relatively low, as well as heavily contaminated soil, from an agricultural chemical waste (evaporation) pit. Endosulfan I, the major isomer of endosulfan, was present in agricultural soils with low (2.2 mg/kg) and high (417 mg/kg) concentrations of technical‐grade endosulfan. The half‐lives of the major isomer of endosulfan were 94 and greater than 350 days in the low‐level (cotton farming soil) and high‐level (contaminated soil), respectively. Even under conditions of minimal intervention, as in the current study, endosulfan concentrations in contaminated soils can be substantially reduced. The nonbiological process of soil binding was predominantly responsible for the natural attenuation of endosulfan I in both soils. Low levels of mineralization of the chlorinated ring 14C‐labelled carbons were also reported, but mineralization did not play an important role in natural attenuation of endosulfan I in either soil studied.