Distribution patterns and major sources of dioxins in soils of the Changsha-Zhuzhou-Xiangtan urban agglomeration, China

Surface soils from an industrial base, the Changsha-Zhuzhou-Xiangtan urban agglomeration in central China were analyzed for 2378-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The PCDD/F concentrations ranged from 268 to 7510 pg g−1 dry weight (dw), 72% of which were above the U.S. guideline value (1000 pg g−1). It was found that octachlorodibenzo-p-dioxin (OCDD) was the most dominant congener accounting for 78.4–99.3% of the total PCDD/Fs, which was consistent with the PCDD/F profiles reported in other Asian countries. It is recommended that the four major sources of PCDD/Fs in the region can be diesel-fuel vehicles, open straw burning, mass burn-water wall (MB-WW), pentachlorophenate (PCP)/PCP-Na and boilers-hazardous waste incineration. This study is one of the few studies with a focus on the PCDD/F pollution in central China, providing evidences for establishing priorities in reduction of ecological risks posed by PCDD/Fs in central China and elsewhere.

► We examine the PCDD/Fs levels in soils from the Chang-Zhu-Tan urban agglomeration. ► PCDD/F concentrations in up to 72% of the samples were above 1000 pg g−1. ► Four major sources contribute to PCDD/Fs pollution in the region. ► It should be helpful for establishing priorities in reduction of PCDD/Fs in China.