Vertical distribution of organochlorine pesticide residue along soil profile in agricultural soils of Huizhou

17 kinds of organochlorine pesticides(OCPs) in 6 agricultural soil profiles of Huizhou City were detected.The residues and distribution of OCPs in the soil were discussed.Results show that OCPs are found in all the samples and the range of OCPs content is 0.25~64.16 μg·kg-1.The content of OCPs decreases with soil depth and the vertical changes of all chemicals of OCPs are different due to various factors.HCHs residues shows low variation alonge the profiles and their highest concentrations are usually found in the subsoil(5~20 cm)in most sample sites.The topsoil contains much more DDTs than the bottom layes of soil.The ration of α-HCH/γ-HCH and DDT/(DDE+DDD)indicates that most of DDTs residues are from historic utilization,while recent Lindane into the environment might be correlated with HCHs,whose control should be enforced.