Observation of Persistent Organic Pollutants(POPs)at Mt Waliguan,a GAW Background Station in Northwest China:Implication for Long-range Atmospheric Transport

摘要

The atmospheric transport of organochlorine pesticides(OCPs)and polybrominated diphenyl ethers(PBDE)was investigated by analyzing air samples of Mt Waliguan,the highest(3810m above sea level)WMO-GAW baseline station and the farthest one from the sea in the world.Concentrations of alpha-HCH,gamma-HCH,HCB,DDTs,DDE and individual PBDEs in 26 air samples were comparable to other remote areas.The low temperature dependence of POPs concentrations and the variability in measured concentrations refer to a long-range atmospheric transport of these chemicals.Backward air trajectory analysis provided consistent evidence that the high air concentrations of gamma-HCH,DDTs and PBDEs may be related to air mass originated from former soviet countries.However,when the air mass came from west China where little anthropogenic pollutant exists,the concentrations of gamma-HCH,DDT and PBDEs were found to be the lowest.