Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in China and chemometric analysis of potential emission sources.

Aimed to give a preliminary image of dioxin pollution in China, chemometric analysis was performed to determine background dioxin levels during the period 1994-2002 and potential emission sources. Using principal components analysis (PCA), the congener profiles of 71 sediment samples from rivers, lakes, and sea bays around China were compared with the congener profiles of various known or suspected industrial, residential, and municipal dioxin sources to determine whether the dioxin residues typically found in a broad range of potential environmental sources could explain the presence of these chemicals in China. It was found that the background dioxin levels of China were similar to those of lightly polluted samples from other countries during the period 1994-2002. Primary ferrous ore sintering and secondary lead and aluminum smelters were the major sources of dioxin emission in China. Chloranil and wastewater from chemical plants, sodium pentachlorophenate, and pulp bleaching were also important sources of dioxin emission. Open burning of e-waste as well as diesel-fueled and leaded gas-fueled vehicles were additional possible sources of dioxin. In contrast to other countries, in China, flue gases from incineration of municipal waste, hazardous waste, and medical waste might be minor sources of dioxin emission.