公路旁侧土壤-植物系统中的重金属分布特征

对内蒙古西部地区国道公路旁侧土壤与植物中重金属（Cd、Hg、Pb、Cu、Zn、Ni、Cr、As和Se）含量以及土壤重金属（Cu、Zn、Pb、Ni、Cr）形态进行测定,分析了公路旁侧土壤和植物油松（Pinus tabulae formis）、小叶杨（Populus simonii）中重金属元素含量特征,分析该区域土壤的重金属分布状况以及重金属的生物有效性。结果表明：Cd、Pb、Cr、Ni、Cu、Zn、Hg、As、Se的含量随距公路垂直距离的分布并不是简单的线性负相关关系。土壤重金属元素的吸附及污染程度以Cd为最高,土壤中Cd、Pb含量偏高可能因为机动车辆运行导致向公路两旁释放Cd、Pb元素。并在土壤中沉积所致。重金属在植物体不同器官中的含量存在一定差异。植物的根部和茎叶中重金属的含量均表现出“N”字形变动趋势。重金属元素有效态占总量百分比的大小序列与重金属元素在不同植物不同器官中的含量大小序列基本相同,5种重金属元素有效态占总量百分比的大小序列为：c（Zn）〉c（Pb）〉c（Ni）、c（Cr）〉c（Cu）,与重金属元素在不同植物不同器官中的含量大小序列趋于一致。

The Distribution Characteristics of Heavy Metals Pollutants in Soil-plant System Along Highway

Through distribution characteristic analysis of the heavy metal concentration in soil,in plants and in soil speciation along the highway in western Inner Mongolia.The result showed that was not simple linearity correlativity between Cd,Hg,Pb,Cu,Zn,Ni,Cr and metalloid As,Se of highway side soil and road uprightness distance.This also shows that the sources of heavy metals from highway are diversified.The highest desorption and adsorption for heavy metals and pollution degree in surface soils are Cd.For the high concentration of Cd and Pb in the highway side soil may be caused by traffic.These released from traffic and sediment in the soils lead to the high concentration.There lies the difference of the heavy metals concentration between the different organs of plant.With the atomic number increased(Cr to Pb),it showed the "N" figure for the concentration of heavy metals in the roots,stem and leaf of Poplar and juniperus.Furthermore the concentration of heavy metals is c(Zn)>c(Pb)>c(Ni),c(Cr)>c(Cu) in the different organs of the different plants.The comparison between the concentration of availability phases in the soils and the concentration of heavy metals in plants shows the same sequence.That is the sequence of percent of the availability phases concentration to the total concentration same as the sequence of the concentrations of heavy metals in the different organs on the different plants.