包头市铜厂周边土壤中重金属垂直分布特征与形态分析

为了解包头市铜厂周边地区土壤剖面中重金属污染状况，采用火焰原子吸收分光光度法和Tessier连续提取法，对土壤中6种重金属（Cu，Zn，Mn，Ni，Pb和Cd）的垂直分布特征、形态及潜在生物可利用性进行了分析。结果表明:研究区土壤剖面各层土壤中6种重金属含量均超过内蒙古土壤背景值，Cu，Pb和Cd为主要污染物。随采样深度的增加，Cu，Zn，Pb和Mn的含量呈现下降趋势，且由相关性系数可知重金属Cu，Zn和Pb可能有相同人为或自然污染源；土壤剖面中6种重金属均主要以残渣态存在，含量均在50%以上，对生物危害较小；潜在生物可利用性分析结果为:Cu（32.61%） > Mn（31.85%） > Ni（24.90%） > Zn（16.60%） > Cd（15.23%） > Pb（14.87%），Cu和Mn的潜在生物可利用性较大，其次为Ni，Zn，Cd和Pb潜在生物可利用性较小。

Vertical Distribution Characteristics and Speciation Analysis of Heavy Metals in Topsoils Around a Copper Plant of Baotou

In order to investigate heavy metal contamination in a copper plant of Baotou City， the flame atomic absorption spectrophotometry and Tessiers sequential chemical extraction technique were adopted to study the vertical distribution characteristics, speciation analysis and potential biological availability analyses of heavy metals (Cu, Zn, Mn, Ni, Pb and Cd) in the soils. The results showed that the six heavy metal elements in the soils exceeded the Inner Mongolia soil background contents, Cu, Pb and Cd were the main pollutants. With the increase of the depth, the concentrations of Cu, Zn, Pb and Mn generally decrease, according to the correlation coefficients， the Cu, Zn and Pb indicate to have the same anthropogenic or natural sources of pollution. The residual fraction was dominant for the six heavy metals, contents were over 50% of the total, less damaging. The result showed the potential biological availability of heavy metal pollution followed the order: Cu (32.61%) > Mn (31.85%) > Ni (24.90%) > Zn (16.60%) > Cd (15.23%) > Pb (14.87%), the potential biological availability of Cu and Mn was relatively high, and the potential biological availability of Ni, Zn, Cd and Pb was lesser.