模拟酸雨下污染土壤中重金属Cd、Zn、Cu的释放特征

Simulation on Releasing Characteristics of Cd,Zn and Cu in Soil Polluted by Acid Rain

通过对自然土壤和污染土壤的模拟酸雨土柱淋溶试验,研究了酸雨作用下土壤中重金属Cd、Zn、Cu的释放特征,比较了自然土壤与污染土壤重金属释放特征的差异。结果表明,自然土壤中Cd、Zn的释放量随淋溶量的增加呈现乘幂式增长,酸雨酸度愈强重金属释放量愈大,3种金属累积释放量之间存在显著的线性关系,重金属释放量顺序为Zn>Cd>Cu,自然土壤对这3种金属吸附能力为Cu>Cd>Zn。污染土壤中Cd、Zn、Cu的释放模式均呈现指数增长,重金属释放量顺序为Cd>Zn>Cu,污染土壤对金属的吸附能力为Cu>Zn>Cd;酸度的增加对污染土壤中Cd、Zn、Cu的释放影响不大。在酸雨作用下,自然土壤由于重金属释放量很小,出现重金属污染的可能性较小。

In this paper,study was made on the releasing characteristics of heavy metal Cd,Cu and Zn in the soil polluted by acid rain and comparison was made on their releasing difference from the natural soil and polluted soil by acid rain through leaching experiments of simulated acid rain for natural soil and polluted soil.The results indicated that the releasing amount of Cd and Zn in natural soil increased linearly with the increase of the leaching amount of simulated acid rain,the stronger the acidity of the acid rain,the larger the releasing amount of the heavy metals,there was a marked linear relation between the accumulative amounts of three heavy metals,the releasing sequence of the heavy metals was Zn >Cd > Cu and the absorbed sequence of heavy metals by the natural soil was Cu>Cd>Zn.In the polluted soil,the releasing mode of Cd,Zn and Cu increased logarithmically,the releasing sequence of heavy metals was Cd>Zn>Cu and the absorbed sequence of the heavy metals by the polluted soil was Cu>Zn>Cd;the acidity increase has a little influence on the releasing amount of Cd,Zn and Cu in polluted soil.The polluted possibility of natural soil by heavy metals under the action of acid rain was relative small due to less releasing amount of heavy metals from it.