绿洲灌淤土重金属复合污染的生物有效性  

Bioavailability of combined heavy metals in oasis soil,arid area of China

作　　者：丁海霞[1] 南忠仁[1] 刘晓文[1] 赵转军[1] 王胜利[1] 李媛[1] 

机构地区：[1]兰州大学资源环境学院西部环境教育部重点实验室,甘肃兰州730000

出　　处：《干旱区地理》2009年第6期924-931,共8页Arid Land Geography

基　　金：国家自然科学基金(NSFC40671167);国家环境保护公益性项目(NEPCP200809098);973项目(2008CB417212)的资助

摘　　要：以干旱区绿洲土壤为供试材料,通过盆栽实验探讨了Cd-Zn-Pb复合污染条件下,土壤重金属在油菜中的分布、累积和迁移情况。研究结果表明,复合污染对油菜生物量的负面影响不明显,甚至还存在一定的促进作用;不同处理下,油菜根部Zn的含量略高于地上部,Cd为油菜地上部含量远高于根部,Pb则主要积累在油菜的根部;Cd、Zn、Pb在油菜体内的累积除了受土壤中本元素浓度的影响外,共存元素对油菜中重金属的累积也有一定的影响。随着外源重金属添加量的增加,土壤中可交换态Cd、Zn、Pb的分配系数均呈增加趋势,且随浓度的增加而增幅变大;碳酸盐结合态和铁锰氧化物结合态的分配系数均为先增加后变化不明显或略有下降;残渣态的分配系数则均呈现出下降趋势,且在浓度较低时的下降态势比较明显。对油菜重金属吸收量影响比较显著的形态为Cd的可交换态、Zn的可交换态和碳酸盐结合态以及Pb的可交换态和碳酸盐结合态。油菜对Cd、Pb、Zn的富集系数和转运系数及富集量系数和转运量系数的关系均为Cd>Zn>Pb。A simulated test of compound contamination by Cd, Zn and Pb was carried out for the oasis soil. In order to study the compound effects of Cd - Zn - Pb, the migration, accumulation and distribution of Cd, Zn and Pb in rape were also studied. The results indicated that, the combination of Cd - Zn - Pb did not cause obvious inhibition on growth of rape, even brought about certain promotion. Under different treatments, the contents of Zn in the rape roots were slightly higher than that in the rape stems and leaves, while the contents of Cd in the rape stems and leaves were far higher than that in the roots, Pb was mainly accumulated in the roots of rape. The accumulation of heavy metals in rape was not only affected by themselves but also by their co-existent elements. With the increase of the contents of Cd, Zn, Pb in oasis experimental soils, the distribution coefficients of Cd, Zn, Pb of exchangeable fractions increased, and the rates of increase became higher as the added contents increasing. The distribution coefficients of Cd, Zn, Pb of carbonate fractions increased obviously at first, then increased non-obviously or decreased slightly. The distribution coefficients of Cd, Zn, Pb of iron-manganese oxides fractions had the same change tendency as carbonate fractions. The distribution coefficients of Cd, Zn, Pb of residual fractions presented a drop tendency, especially in low added contents, there was a sharp change. The fractions which were most significandy correlated with the amount of heavy metals absorbed by each part of rape were Cd of exchangeable fraction, Zn of exchangeable and carbonate fractions, Pb of exchangeable and carbonate fractions. The relation of absorption coefficients with transformation coefficients of rape to Cd, Zn and Pb was equally Cd 〉 Zn 〉 Pb. What＇s more, absorption capacity coefficients and transformation capacity coefficients had the same results.

关 键 词：重金属 油菜 盆栽试验 复合污染 

分 类 号：X53[环境科学与工程—环境工程]