Characteristics of Heavy Metal Distribution and Grain Size in Surface Sediments of Barchan Dunes of the Wuhai Section in Ulan Buh Desert
This study focused on barchan dune of Wuhai section in Ulan Buh desert.By integrating sampling investigation with laboratory experiment,the study determined the characteristics of heavy metals(Mn,Cu,Zn,Cr and Fe) and grain size of surface sediments from surface soil and dustfall of barchan dunes,as well as the correlation between heavy metals and particle size.The sources of heavy metal and its potential ecological risk were also analyzed.The results showed that:(1)The sediment grain were dominated by very fine sand and fine sand on barchan dunes and mainly contained very fine sand and silt in dustfall.However,the sediment grain were mainly medium sand and fine sand on upwind dunes and industrialization led to refinement of grain size on the dune surface.(2)The content of different heavy metal of the dune surface and dustfall followed the order:Fe＞Mn＞Cr＞Zn＞Cu,with the contents of Mn,Cu,Zn and Cr all higher than the background value.The contents of heavy metals in dustfall significantly differed with those in sand dunes.The variation coefficient of different heavy metal listed in the following order:Cu＞Fe＞Zn＞Mn＞ Cr.Mn and Zn showed intermediate variability(15％ ～36％),while Fe and Cu were highly variable(＞ 36％).The enrichment of Mn,Zn,Cu and Cr were observed and their enrichment coefficients were all higher than 1.(3)The contents of Mn,Zn and Cu were positively correlated with that of fine particle,while the contents of Zn and Cu were negatively correlated with that of medium sand,and Fe content showed negative correlation with all heavy metals.(4)The major source of Cu,Zn and Cr was industrial pollution.A part of Fe and Mn also came from industrial pollution and a part of Cu and Zn came from the daily life of human.The rest heavy metals were from earth weathering.The results indicated that Barchan dunes in study area were in the state of low ecological risk.However,the enrichment of Mn,Cu,Zn and Cr should be well controlled.
国家科技期刊平台
NSTL
万方数据
维普
