Abstract:Persistent organic pollutants (POPs) listed in the Stockholm Convention of 2000 all belong to the category of organochlorine chemicals and deserve high priority for investigation. However, researches on organochlorines in Hong Kong area used to be focused mainly on those in sediments, marine organisms and human milk in the past, and little was reported on their presence in soils. Forty six samples of surface (0~10 cm) soils typical in Hong Kong were collected and analyzed for organochlorine pesticides and polychlorinated Biphenyls with the aid of GC/ECD (gas chromatograph/electronic capturer detector), six Stockholm Convention substances including pesticides and PCBs as well as HCH were detected in the samples and they were lined up in a decreasing sequence of HCH > dichlorodiphenylthrichloroethane (DDT) > hexachlorobenzene (HCB) = Endrin = PCBs > α-endosulfan in terms of concentration. The major components of the organochlorine pesticide residues were β-HCH and p, p'-DDE due to their stable molecular structures compared with other homologues. The average contents of these two compounds were only 6.12 μg kg-1 and 0.41 μg kg-1, respectively, which was much lower than the corresponding target values in the Dutch List. As for the PCBs, five samples were detected to have PCB28 and PCB138, which were lower than 0.1 μg kg-1 in content. Moreover, the regression analysis results presented that residual contents of HCH in the soils were related to pH (KCl) and total organic carbon (TOC) content, but such relationship was not found with the other detectable organochlorines.