不同降雨强度下污染土重金属元素随径流迁移转化特征

Migration and Transformation Characteristics of Heavy Metals with Surface Runoff Under Different Rainfall Intensities in Contaminated Soil

通过室内模拟降雨试验,研究了不同降雨降雨强度下(29.9,55.2,78.5mm/h)空白土和污染土Cu、Pb和Zn随地表径流的迁移转化特征。结果表明,空白土与污染土径流携带的泥沙量均随降雨强度的增大而增大,土壤受重金属污染对侵蚀泥沙量的变化影响不大;污染土径流中水溶态Cu、Zn含量明显高于空白土含量,且基本不受降雨强度影响,其大小主要由土壤酸溶态中的可交换态含量决定,3种重金属水溶性含量大小为Zn>Cu>Pb;不管对于空白土还是污染土,径流中重金属总浓度都随降雨强度的增大而增大,但污染土增加的幅度明显比空白土大,且与泥沙量变化趋势基本一致,而空白土无此规律。

The effects of different rainfall intensities （29.9,55.2,78. 5 ram/h） on migration and transtormanon ot Cu,Pb,Zn with surface rainoff from heavy contaminated soil were studied by simulated rainfall experiments. The results showed that the eroded sediment whether from blank or contaminated soil was increased with increasing of rainfall intensity. There was little effects of the eroded sediment in contaminated soil. The contents of water solubility of Cu and Zn in runoff from contaminated soil were significantly higher than that from blank soil and were mainly determined by exchangeable content in soluble acid state of soil. The size of water solubility of heavy metals in soil was Zn〉Cu〉Pb. Meanwhile,with the increase of rainfall intensity, the total amount of heavy metals loss also increased and the increment of contaminated soil was sharply bigger than that of blank soil. The similar changes of tendency was observed between total heavy metals and sediment of contaminated soil, but no regularity changed of blank soil.