Preliminary Study On Pollution Characteristics And Source Analysis Of POPs From PM_2.5 In Hangzhou

Polychlorinated dibenzo-p-dioxins(PCDDs), polychlorinated dibenzofurans(PCDFs), polychlorinated biphenyls(PCBs) and polybrominated diphenyl ethers(PBDEs) are a group of persistent organic pollutants(POPs) that are ubiquitous in the environment. We performed an investigation focused on evaluating the concentrations and distributions of PCDD/Fs, PCBs and PBDEs in atmospheric fine particles(PM2.5).In addition, some PCDD/Fs emission sources impacting on Hangzhou atmospheric quality and human risks of PCDD/Fs and DL-PCBs via inhalation were studied preliminarily.It mainly results as follows :PM2.5 samples were collected concurrently in each of the four seasons, five sampling sites in Hangzhou. The results showed that the annual average concentrations of PM2.5 was 102 μg/m3, which suggested that the PM2.5 pollution was relative serious in Hangzhou, yet it has improved when compared with the results of 2004.The mass concentrations of PM2.5 at different times in the same area or different areas in the same time had a significant difference.The spatial distribution and seasonal pattern of PM2.5 has certain characteristics.The levels of PCDD/Fs, DL-PCBs, PBDEs(excluding BDE-209) and BDE-209 in PM2.5 samples were varied from 0.107-0.488 pg I-TEQ /m3,1.6-16.2 fg WHO-TEQ/m3,3.5-12.5 pg/m3 and 7.4-35.5 pg/m3, respectively.The atmospheric concentrations of PCDD/Fs were decreased in the developed country, but on the contrary, the contamination trends of PCDD/Fs in Hangzhou were increased year by year. Compared to some abroad studies, the concentrations of PCDD/Fs in this study were higher than those found in similar studies;but the concentrations of PCBs and PBDEs in PM2.5 were much lower than reported,which means the pollution of PCBs and PBDEs were in good condition.As the season changes,relative distributions of PCDD/Fs between gas and particle phase had the regularity. PCDD/Fs mainly distributed in the gas phase during the winter,but dominated in the particle phase in summer. However, this regularity was not observed for PCBs and PBDEs.PCBs were mainly distributed in the gas phase and PBDEs were contributed dominantly to particles for a year. Distribution patterns of PCDD/Fs, PCBs and PBDEs had temporal and spatial characteristics in different sampling sites and seasons.Some emission sources impacting on Hangzhou atmospheric quality were studied preliminarily.The results from a congener specific factor analysis reveled that the emission from vehicles, steel smelting and burning sources around were the major sources that accounted for atmospheric PCDD/Fs pollution. The extensive produce and use of deca-BDE made concentrations of BDE-209 measured higher in China.The dioxin daily via inhalation of PCDD/Fs and PCBs by the local adults and children were 164.6 fg TEQ/kg/day and 292.5 fg TEQ/kg/day, respectively.The risks of site E was little higher than site A, children intake was higher than adults. Human health was in the scope of acceptable risk when there is some exposure.