湖南典型地区大气降水与下渗水元素地球化学特征及其影响因素研究
Geochemical Characteristics and Influence Factors of Elemental Contents in Rainfall and Leaching Water in the Typical Areas of Hunan

摘要： 对比了湖南典型地区大气降水与下渗水中阴离子含量、Cd等重金属元素含量特征，并研究了Cd等重金属元素下渗的影响因素。研究表明，郴州市和株洲市大气降水中SO42-含量均比桂东—汝城地区和岳阳市高，郴州市和株洲市大气受到较为严重的污染。郴州市和株洲市大气降水及土壤中Cd等重金属元素含量均明显高于桂东—汝城地区和岳阳市，但下渗水中Cd等重金属元素含量差异不大。用元素浓度下渗比(下渗水中重金属元素含量/大气降水中重金属元素含量)来表征水循环过程中土壤重金属元素的累积性，结果显示郴州市和株洲市降水对土壤Cd等重金属元素累积的贡献大于桂东—汝城地区和岳阳市。综合对比表明郴州市和株洲市表层土壤Cd等重金属元素累积明显。影响Cd等重金属元素下渗的因素非常复杂，其中土壤有机碳和pH是控制As、Cd和Pb下渗的主要因素。
Abstract: This paper reported the characteristics of ion and heavy metal element contents such as Cd in rainfall water and leaching water in typical areas of Hunan, China, and discussed the leaching influence factors of heavy metal elements. The results showed that the contents of SO42-and heavy metal elements in rainfall water in Chenzhou and Zhuzhou were both significantly higher than those of GuidongRucheng as well as Yueyang. The air pollution was more serious in Chenzhou and Zhuzhou. However, such obvious differences were not detected in leaching water. Here, the ratio of leaching concentration(heavy metal element contents in leaching water/ heavy metal element contents in rainfall water)was used to show accumulative difference of heavy metal elements. The results indicated that the contribution of rainfall to the accumulation of heavy metal elements such as Cd in soils in Chenzhou and Zhuzhou was greater than those of GuidongRucheng and Yueyang. It obviously illustrated that the heavy metal elements such as Cd in surface soil had an accumulating trend in Chenzhou and Zhuzhou. The leaching influence factors of heavy metal elements are very complicated, of which organic carbon contents and pH of soil are the key factors to control the leaching capacities of As, Cd and Pb