赤泥对重金属污染稻田土壤Pb、Zn和Cd的修复效应研究

目的]研究赤泥对矿区重金属污染稻田土壤中Pb、Zn和Cd的修复效应,阐明其对重金属污染土壤的修复机理及肥效机制。方法]通过土壤培养试验,研究了赤泥对土壤pH值和电导率(EC)的影响,探讨了其对土壤Pb、Zn和Cd重金属的修复效应。结果]赤泥能显著降低土壤中交换态Pb、Zn和Cd含量,当赤泥用量为4%(W/W)时,培养30、60和90 d后,交换态Pb含量分别比不施赤泥的对照处理下降了39.25%、41.38%和50.19%;交换态Zn含量分别比对照下降了49.26%、57.32%和47.16%;交换态Cd含量分别比对照处理下降了19.53%、24.06%和25.70%。施用赤泥对土壤5种形态Pb、Zn和Cd所占总Pb、Zn和Cd的比重有明显影响,不同赤泥处理均降低了土壤中交换态Pb、Zn和Cd占总Pb、Zn和Cd的比重,且该3种重金属各自所占比重均随赤泥施用量的增加而下降。结论]该研究为赤泥在稻田土壤上的合理施用以及其减少稻田土壤重金属污染的研究提供参考依据。

Effects of Red Mud on the Remediation of Pb, Zn and Cd in Heavy Metal Contaminated Paddy Soil

Objective]To study the remediation efficiency of red mud on Pb,Zn and Cd in the heavy metal contaminated paddy soil of mine area,to clarify its remediation mechanism and fertilizer efficiency on heavy metal contaminated soil.Method] The soil incubation experiment was conducted to study the effect of red mud on the pH values and electrical conductivity(EC),and the remediation efficiency on lead(Pb),zinc(Zn) and cadmium(Cd) in heavy metal contaminated soil.Result] Red mud addition reduced the content of exchangeable Pb,Zn and Cd in the soil significantly.Compared with the control,when incubated for 30,60 and 90 d with the red mud dosage of 4%(W/W),the exchangeable Pb content was decreased by 39.25%,41.38% and 50.19%;exchangeable Zn content was decreased by 49.26%,57.32% and 47.16%;and exchangeable Cd content was decreased by 19.53%,24.06% and 25.70%,respectively.The application of red mud had significant impact on the share of Pb,Zn and Cd contents in five forms,and different amounts of red mud application all reduced the proportion of exchangeable Pb,Zn and Cd to the total Pb,Zn and Cd.Furthermore,the proportion of exchangeable Pb,Zn and Cd to total Pb,Zn and Cd decreased with the increasing amount of red mud addition.Conclusion]The study provided references for research on reasonable application of red mud and reduction of heavy metal pollution in paddy soil.