Composition And Environmental Behavior Of Pbeds From Typically Local Sources In The Tibetan Plateau

As a typical background region,we usually think the source of persistent organic pollutants(POPs)in the Tibetan Plateau(TP)is long-range atmospheric transport.However,as the study progressed deeper,it was found that the heavy compounds reflected local sources appeared,so understanding its distribution and composition characteristics,and the contribution of local sources in the TP has become a problem to be solved.Due to the lack of research on local sources in the TP,Lhasa landfill is a typical local source of POPs.As an important sink of the used POPs,it could reflect the local POPs in the TP.Therefore,it may help us understand the composition and environmental behavior of the local POPs well to study the Lhasa landfill,and thus we would have a general understanding of the level of POPs in the TP.The object of this study is the largest landfill in the TP,PBDEs in the environment are the target of research.A waste soil was collected at the landfill site and we also collected 5 soil profiles and 7 surface sediments around it.The PBDEs concentration and composition characteristics in the spatial and vertical directions were studied.The concentration of PBDEs in surface soil ranged from 559 to 1219 ng/kg,and PBDEs were also found in deeper soils.The concentration in surface sediments ranged from 447 to 7295ng/kg,of which nona-and deca-BDEs dominate,indicating that the deca-BDE mixture was widely used as flame retardant in the TP.According to principal components analysis and multiple linear regression,the atmospheric dispersion and leachate seepage were considered as the two main transport pathways for PBDEs released from waste into soils,and they accounted for 62% and 38% of total contributions,respectively.In addition,the soil particle size had a significant effect on the spatial distribution of octa-to deca-BDEs,and the distribution of tri-to hepta-BDEs is greatly affected by SOC.Although the content of PBDEs in the soils and sediments in the study area were relatively low,the rapid urbanization process in the TP may greatly increase the inputs of PBDEs in the future,which affects the surrounding environment.Once local PBDEs participate in the regional cycle,the increase of inventory may significantly improve the level of background values in the TP.Therefore,it is very meaningful and valuable to study the local source of PBDEs in Tibetan Plateau.