Concentration And Sources Of Polychlorinated Biphenyl At Mount Heng, China

PCBs are semi-volatile organochlorine compounds with persistence, toxicities and bio-accumulative properties. To study the content of PCBs can provide basis for pollution prevention and control of PCBs. Mount Heng, the sampling point of this study, is in the south of China, and is representative of the area both in the aspect of location and climatic characteristics. The aim of this study is to add data of PCBs in high-mountain areas of China, obtain insights about long-range transport and the source of PCBs in this area.Sampling was conducted at the Mount Heng Weather Station between March and May,2009.34pairs of vapor and particulate samples and22times of cloud/fog water samples were obtained.7indicator-PCBs were detected by GC.The mean value of the7indicator-PCBs in atmosphere was180.51pg·m-3, while the dominate PCB congener was PCB52, which accounted for60.2%of the total content. High-chlorinated PCBs tended to be attached to particulate matter, while low-chlorinated PCBs preferred to distribute in the gas phase. The concentration of PCBs in atmosphere of Mount Heng was higher than that of11background points in China, lower than that of cities inland, and above or close to the levels of some foreign cities. Compared with high-mountain sites overseas, the PCBs concentration here was in a high level. The study of the relevance between PCBs content in atmosphere and temperature showed that, there was no good relation between the two. It could be considered that the content of PCBs of this area was impacted mainly by the long-range transport.The mean value of the7indicator-PCBs in cloud/fog water was86.81ng/L, while the dominate PCB congener was PCB52, too. Low-chlorinated PCBs were more than high-chlorinated PCBs. Total PCBs in particulate phase were a little more than those in aqueous phase. For the4low-chlorinated PCBs, their content in aqueous phase and particular phase was the same except for PCB52. High-chlorinated PCB153and PCB180was mostly present in the particulate phase.Back trajectory analysis indicated that airflows during the air sampling date can be divided into N and S two categories, while those of the cloud/fog water sampling date can be divided into N, S and L there categories. The category of N contained more PCBs both in the air and in the cloud/fog water.The outcome of principal component analysis showed that the sources of PCBs in this region could be mainly divided into two parts:one includes the release of incinerators, industrial processes such as paper bleaching and PCB products which were made in China, and the other represents PCB products made in foreign countries.