[Characteristics of dioxin-like polychlorinated biphenyls contamination in soils of Gudao Region in Dongying].

To investigate pollution characteristics of dioxin-like polychlorinated biphenyls (DL-PCBs) in Gudao Region, Dongying City, twenty surface soil samples were collected in April, 2011. The DL-PCBs in soil samples were determined by Soxhelt extraction-Florisil purification-Gas Chromatography(GC)-Electron Capture Detector (ECD). The concentration of DL-PCBs in surface soils ranged from 1.4 microg x kg(-1) to 7.4 microg x kg(-1), with the mean concentration of (3.5 +/- 1.7) microg x kg(-1). The total TEQ level was between 1.2 ng x kg(-1) and 31.8 ng x kg(-1), and the mean TEQ was 5.4 ng x kg(-1), which exceeded the Canadian soil environment quality guidelines (4.0 ng x kg(-1)). The congener profiles of DL-PCBs were similar among sites. Tetra-CB and penta-CB were the major homologues in all soil samples, together accounting for more than 80% of the total DL-PCBs. The level of DL-PCBs exhibited a decreasing trend with the increasing distance from the Gudao town to the suburb, which could be attributed to the chemical plants around the town. The correlation analysis showed that the concentration of DL-PCBs was positively correlated with the organic matter content and clay particle content (R2 were 0.732 and 0.687, separately, P < 0.01), but negatively correlated with the sand particle content (R2 = -0.438, P < 0.05).