新乡小冀工业区周边土壤重金属污染评价与形态分析

Pollution evaluation and form analysis on heavy metals in soils around Xiaoji industrial zone,Xinxiang

通过实地调查和实验分析,对小冀工业区周边土壤中六种重金属(Cd、Cr、Cu、Ni、Pb和Zn)进行了总量测定。参照GB15618-1995二级标准,采用单因子指数法和内梅罗综合污染指数法对土壤质量进行了现状评价,并采用Tessier五步连续萃取法对超标重金属Cd、Ni和Zn进行了形态分析及生物活性分析。结果表明:1)Cr、Cu和Pb含量均未超过国标二级标准,Cd、Ni和Zn三种重金属含量均超标,工业区综合污染非常严重,主要污染元素是Cd;2)Cd、Ni和Zn在土壤中的形态分布差异性较大,Cd主要以铁锰氧化物结合态存在,Ni和Zn主要以残渣态和铁锰氧化物结合态存在;3)金属生物活性系数大小顺序为Cd>Zn>Ni,迁移系数的大小顺序是Cd>Zn>Ni,其中Cd的生态风险很大。

Through field surveys and laboratory analysis, the contents of 6 kinds of heavy metals （ Cd, Cr, Cu, Ni, Pb and Zn）in soils around Xiaoji industrial zone were measured. Reference to the standard of GB15618 - 1995, soil pollution was evaluated by using of single factor index and Nemerow pollution index method. Using Tessier sequential extraction procedure, the forms and biological activity of excessive heavy mentals （ Cd, Ni and Zn ） were analyzed. The results show that： 1） Cr, Cu and Pb do not exceed the standard of GB15618 -1995, the contents of Cd, Ni and Zn are excessive, and the industrial zone is polluted seriously and the major pollution element is Cd ; 2） The forms of Cd, Ni and Zn in soils are quite different, the major form of Cd is iron - manga- nese oxides fraction, Ni and Zn are dominated by the residual fraction and iron -manganese oxides fraction; 3） The metal biological activity coefficient of the order is Cd 〉 Zn 〉 Ni, and the order of the migration coefficient is Cd 〉 Zn 〉 Ni, and he ecological risk of Cd is serious.