Composition And Spatial Distribution Of Elements In Xanthoria Mandschurica From The Mountains Of Beijing To Qinhuangdao

Lichens are a symbiotic association of Fungi and photobionts(cyanobacteria or green algae).These organisms have a strong ability to accumulate metals from the atmosphere and are considered to be a good bioindicator for detecting atmospheric pollution.The air in Beijing,Tianjin,Hebei,and the surrounding regions has been heavily polluted in recent years.However,the effects of these pollutants on lichen elemental composition in the mountains from Beijing to Qinhuangdao are still unclear.In this study,the lichen Xanthoria mandschurica were collected from 41 sites in Yanshan Mountain,and 43 elements(Al,B,Ba,Bi,Ca,Cd,Ce,Cs,Cu,Dy,Er,Eu,Fe,Gd,Ho,K,La,Li,Lu,Mg,Mn,Na,Nb,Nd,Ni,P,Pb,Pr,Rb,S,Sb,Si,Sm,Sr,Tb,Th,Ti,Tl,Tm,V,Y,Yb,and Zn)in lichen thalli were measured by inductively coupled plasma mass spectrometry(ICP-MS).Spatial patterns and sources of these elements were analyzed using the clustering analysis,principal component analysis,enrichment factor analysis,Kriging analysis and other methods.The results show that Xanthoria mandschurica is a good biomonitor for atmospheric element deposition.Eight elements(Bi,Cd,Cu,Pb,S,Sb,Tl,and Zn)were possibly of anthropogenic origin.P and K exhibit roughly similar spatial distributions that are contrary to the anthropogenic pollutants,indicating that concentration of both elements in the lichen may be a result of interactions between atmospheric pollutant deposition and lichen physiological regulation.The other elements were mainly of crustal origin and their release and transportation have been simultaneous with the anthropogenic elements.According to the results of the analysis,it can be concluded that the air quality has been highly influenced by the long-range transportation and local emission of atmospheric elements.Air quality in the Zhang jia kou-Zhuo lu region has been highly affected by the local anthropogenic emissions and the deposition of sand dusts transported from Inner Mongolian Plateau.Air quality in the regions surrounding Beijing city has been greatly impacted by the local anthropogenic emissions and long-range transportation from NorthChina Plain.Air quality of montane areas north of Tangshan city has been highly influenced by the transportation of atmospheric pollutants from the Plain,especially from the steel plants.