Contamination by selected organochlorine pesticides (OCPs) in surface soils in Hanoi, Vietnam

An evaluation of selected organochlorine pesticide residues [p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodiphenyldichloroethylene (DDE), p,p'-dichlorodiphenyldichloroethane (DDD), alpha, beta, gamma and delta- hexachlorocyclohexane (HCH)] in the surface soils of Hanoi, Vietnam was carried out. Sixty representative soil samples were collected from the centre of Hanoi and five surrounding districts. In agricultural areas, Sigma DDT concentrations ranged from < 0.02 to 171.83 ng g(-1) (mean 89.86 ng g(-1)) dry weight, whereas Sigma HCH concentrations ranged from < 0.05 to 20.57 n g g(-1)(mean 8.03 ng g(-1)) dry weight. Investigation of the ratio of different isomers in the soil samples indicates that there has been no recent input of DDT and HCH in the study area.