Composition And Spatial Distribution Of Chemical Elements In Xanthoria Elegans From Taiyue Mountains,Shanxi Province

Lichens are a kind of reciprocal symbiosis composed of fungi and photosynthetic organisms(algae or cyanobacteria).Their special morphology and physiology rank them one of the best biomonitors of environmental conditions.Using the lichen elemental compositions to evaluate the local atmospheric elemental deposition is important in the control of air pollution in China.Shanxi Province is a major coal-producing province in China,and has a large population and heavy air pollution in the basins.However,the atmospheric element deposition patterns in this region is still unclear.In this study,the foliose lichen Xanthoria elegans were collected from 31 sites of Taiyue Mountains,Shanxi Province.This lichen belongs to Xanthoria,Teloschistaceae,Teloschistales,Lecanoromycetes,Ascomycota,Fungi.After cleaning and grinding the lichen thalli,45 elements(Al,As,Ba,Be,Bi,Cd,Ce,Cr,Cs,Cu,Dy,Er,Eu,Fe,Gd,Ge,Ho,K,La,Lu,Mn,Mo,Na,Nb,Nd,Ni,P,Pb,Pr,Rb,S,Sb,Sc,Si,Sm,Sr,Tb,Th,Ti,Tm,U,V,Y,Yb,Zn)in the samples were analyzed by using an inductively coupled plasma mass spectrometer(ICP-MS).To explore the element compositions and their spatial patterns,we cconducted several statistical analyses,such as cluster analysis,factor analysis,correlation analysis,one-way ANOVA,enrichment coefficient,pollution load coefficient,and Kriging mapping.The results show that:(1)34 elements(Al,Ba,Be,Ce,Cr,Cs,Dy,Er,Eu,Fe,Gd,Ge,Ho,La,Lu,Mn,Na,Nb,Nd,Ni,Pr,Rb,Sc,Si,Sm,Sr,Tb,Th,Ti,Tm,U,V,Y,Yb)are mainly of crustal origin,and are predominantly dispersed from Taiyuan-Jinzhong-Xiaoyi-Jiexiu Basins,Linfen Basin,Changzhi Basin and Jincheng-Jiaozuo Basins.(2)Eight elements(As,Bi,Cd,Cu,Mo,Pb,Sb,Zn)are mainly of anthropogenic orgin and are predominantly related to human activities in the basins.The Linfen Basin,Changzhi Basin and Jincheng-Jiaozuo Basins are the regions that have released pollutant elements in highest amount.(3)The three elements(K,P,S)are related to both human activities and lichen physiology.They pose the spatial patterns opposite to the eight pollutant elements and 34 crustal origin elements,and show little differences between the sites nearfrom the basins and the sites remote from the basins.These patterns are attributable to the interactive effects between the release by anthropogenic activities and the active and selective uptake by the lichens.Through the above results,we conclude that:(1)Xanthoria elegans can be used to monitor the sources and spatial patterns of atmospheric pollutants,especially those of the heavy metals in the study area,and is suitable for large-scale spatial scale monitoring of atmospheric element deposition.(2)The anthropogenic release of human activities in the basins and local anthropogenic activities are main sources for the decline of air quality in the study area.The Linfen Basin,Changzhi Basin and Jincheng-Jiaozuo Basins are the most important source of anthropogenic elements.Besides,the Taiyuan-Jinzhong-Xiaoyi-Jiexiu Basins may also be affected by the dust from the Inner Mongolia,Shaanxi and Shanxi Province.(3)In the study area,atmospheric pollution illustrated by lichen elements shows a trend of shifting from basin to mountainous area.Therefore,the entire Taiyue Mountains may suffer heavy air pollution in the future if the pollution source of the basin is not controlled.