Distribution of Chlorinated Insecticides in Cultivated Soil

Abstract The 1966 distribution of nine chlorinated insecticides in a 38 cm profile was determined in a Congaree sandy loam soil which had received accumulations of 73 or 146 kg/ha as frequently repeated foliar applications during the 1951, 1952, and 1953 growing seasons. Residues of aldrin (pure and technical—determined as dieldrin because only trace amounts of aldrin were detected), dieldrin, isodrin + endrin, endrin, heptachlor + heptachlor epoxide, chlordane, BHC, toxaphene, and Dilan were found throughout the profile. BHC and isodrin were more uniformly distributed throughout the profile than aldrin, dieldrin, Dilan, toxaphene, and chlordane. Between 85 to 90% of the latter insecticides were concentrated in the upper 23 cm, which probably corresponds to the cultivated layer. Residues were greatest in the 7.6 to 23 cm depths and least below the 23 cm depth. The relative mobility of the insecticides was: BHC ≥ isodrin > heptachlor > endrin > toxaphene ≥ dieldrin ≥ aldrin ≥ Dilan ≥ chlordane.