Determination of HCH and DDT in soils following Wenchuan 5.12 Violent Earthquake in China

A large number of disinfectants and insecticides were used on a large scale after the Wenchuan 5.12 Violent Earthquake. The disinfectants and insecticides, including HCH (hexachlorocyclohexane) and DDT (dichlorodiphenyltrichoroethane) as representative OCPs, could lead to serious environmental problems. In order to disclose the residues of HCH and DDT in soils following the Wenchuan 5.12 Violent Earthquake, surface soils in Dujiangyan City and Beichuan County were sampled in 2009. The samples were analyzed by GC/MS after pre-treatment by ultrasonic solvent extraction. It has been found that the concentrations of γ-HCH, β-HCH and 4,4′-DDT in soils of Beichuan County were 94–102.4, 14.1–36.1 and 2.9–4.3 times high their concentrations in those of the Wolong Nature Reserve, and the concentrations in soils of Dujiangyan City were 52.4–61.6, 8.8–45.3 and 5.4–6.2 times high their concentrations in soils of the Wolong Nature Reserve, respectively. According to the isomers of HCHs and metabolites of DDTs, it could be concluded that these areas may have additional inputs of lindane and 4,4′-DDT.