垃圾渗滤液中溶解性有机物对土壤中重金属迁移的影响

Impact of dissolved organic matter in landfill leachate on migration of heavy metals in soils

垃圾渗滤液主要组分中含有重金属和大量的溶解性有机物(DOM)。实验选用北方最具代表性的褐土为供试样品,通过室内土柱淋滤实验研究了垃圾渗滤液溶解性有机物对重金属Cu、Cd、Pb和Zn在土壤中的迁移行为的影响。结果显示,DOM对土壤中Cd、Zn的垂直迁移起着促进作用,而对Cu、Pb迁移起着一定的抑制作用;不同浓度的垃圾淋洗液DOM对土壤中重金属的迁移溶出效果不同,DOM浓度越高,Cd、Zn溶出的促进效果越明显,Cu、Pb则恰好相反;垃圾淋洗液DOM对土壤重金属的平均迁移量随时间的延长而减少。同时在土壤溶质运移模型的基础上,确立重金属元素在土壤中迁移转化模型,对预测污染物的时空分布和土壤重金属污染治理提供科学依据。研究可以为固体废物的土地利用提供理论指导。

The main component of the landfill leachate contains heavy metals and many dissolved organic matters（DOM）.The cinnamon soil used for the test is the most typical soil in the north China.The study considered the effect of dissolved organic matter from landfill leachate on migration of Cu,Cd,Pb and Zn in soils by column experiment.The results showed that the DOM played a promoting function for the vertical migration of Cd and Zn in soils,meanwhile,it played a certain extent inhibitory effect for the migration of Cu and Pb.The different concentrations DOM had different influence for migration of the heavy metals in soil,the higher concentration of DOM,the more obvious the dissolution of Cd,Zn,which was contrary to Cu and Pb.The average migration quantity of DOM to the heavy metals in soils decreased as the extension of time.The model is established about migration and transformation of heavy metals on the basis of soil solute transport model,it provides the scientific foundation for the prediction of the temporal and spatial distribution of pollutants and the pollution control of the heavy metals in soils.The study can provide theoretical guidance for land use of the solid waste.