刁江沿岸土壤重金属污染特征研究

受上游矿山开发的影响，刁江沿岸存在明显的As、Pb、Zn、Cd复合污染带，其污染区与洪水淹没区呈现高度的一致性；水田的犁底层对重金属具有明显的隔断作用，而旱地的淀积层中的重金属质量分数依然很高；上游地带土壤污染呈显性状态，土壤中尾砂沉积现象十分明显，而下游地带的土壤污染呈隐性状态，土壤中尾砂沉积现象不明显；蜈蚣蕨可以作为刁江沿岸土壤污染区的指示植物；土壤中Zn与Cd质量分数存在显著相关关系，表层土壤As与Pb质量分数呈现较好的相关性，而土壤垂直剖面中As与Pb质量分数除个别剖面外，相关关系不显著。

The characteristics of heavy metals in soils along Diaojiang river

Due to mining activities, soils along Diaojiang river in Guangxi, China, have been severely polluted by As, Pb, Cd and Zn. The soil pollution survey indicates that the contaminated area is coincided with the flooded area. The plowpan of paddy field can obstruct the transport of heavy metals downwards, but the B horizon of dry farmland contains high levels of heavy metals. There are obvious tailings deposits in soils at upper region of Diaojiang, and such phenomena disappear at the lower region. Pteris vittata L. can be used as pollution indicator of soil along Diaojiang river. The concentration of Zn is significantly correlated with that of Cd in soils, but only in topsoils except one sample significant correlation exists between As and Pb.