三峡库区消落带土壤重金属含量特征及污染评价

摘要

以三峡库区蓄水位从175m回落至163m后的云阳段消落带土壤为研究对象，进行重金属Cu、Zn、Pb、Cd和Cr的含量与剖面分布特征及评价研究。结果表明：消落带土壤Cu、Zn、Pb、Cd和Cr的含量分别为58.09mg/kg、108.93mg/kg、15.18mg/kg、0.46mg/kg和71.81mg/kg。重金属剖面分布特征呈规律性变化：0～10cm土层Cu、Cr和Zn含量高于10～20cm土层，而在干湿交替处Zn、Cr含量却表现为0～10cm土层低于10～20cm土层；Pb和Cd剖面分布特征均呈现出0～10cm土层含量低于10～20cm土层，而在干湿交替处呈相反趋势。研究区不受Pb污染，而受Cd、Cu、Zn和Cr不同程度污染，尤以Cd污染最严重，甚至超出三峡库区土壤背景值3倍以上。%This study was devoted to fluctuation zone of Three Gorges reservoir area in Yunyang and the concen-trations of Cu,Zn,Pb,Cd and Cr were determined which ranged from 175m to 163m in water-level-fluctuating zone soils. The result indicated that the total concentrations of Cu,Zn,Pb,Cd and Cr were 58.09mg/kg,108.93mg/kg,15.18mg/kg,0.46mg/kg and 71.81mg/kg,respectively. The profile distribution characteristics of heavy metal con-tent changed regularly:the content of Cu,Cr and Zn in surface soil is higher than that of in the deep soil,but the content of Cr and Zn in surface soil is lower than that of in the deep soil at the dry-wet alternation;Con-tent characteristics of Pb and Cd was the same,emerged as the surface is less than deep and the surface is more than deep at the dry-wet alternation. The study area was contaminated by Cd,Cu,Zn and Cr in varying de-grees,but far from the Pb pollution;however pollution of Cd was particularly serious,even beyond the background value more than three times.