模拟酸雨作用下红壤剖面元素活化迁移规律研究

发布时间：2018-07-02 19:50

本文选题：酸雨 + 红壤剖面　；参考：《中国地质大学(北京)》2016年硕士论文

【摘要】：福建省漳州龙海市位于中国东南沿海,工业发达,是我国主要的酸雨地区之一;该区地处南亚热带季风气候,雨量充沛,加上频繁的酸雨沉降导致土壤营养元素(Ca、Mg、K、Na等)大量淋失,土壤酸性强,进一步酸化有可能使土壤和岩石等自然介质中重金属及铝等化学元素的活化溶出,影响作物生长发育、水环境质量,存在较大的生态风险。本文选择龙海市境内地质背景和土地利用具有代表性的两个地点采集土柱剖面,开展模拟酸雨淋滤实验,取得以下认识:1.研究区土壤风化程度高,常量元素(Ca、Mg、K、Na)淋失严重,Al相对富集,土壤风化程度达到脱硅富铝阶段。剖面中微量元素的分布特征往往受常量元素的控制。2.溶出元素浓度随淋滤液酸性增强而增加,随淋滤土层的加深而增加;随着淋滤实验的逐次推进,土壤淋出液中多数元素浓度呈逐渐降低趋势。3.淋滤液中常量元素浓度按其土壤-溶液分配系数及淋出液浓度的纵向分布特征可以将其分为三组:第1组为Ca、Mg、K、Na;第2组为Al、Fe;第3组Si。第1组元素活动性强,在淋滤过程中极易活化溶出进入溶液,而第2、3组元素活动性较弱。4.淋滤液中微量元素的溶出规律显示受常量组分的支配。根据微量元素溶出浓度特征将其分为以下四组:第1组为Cu、Cd、Hg、Ni、Pb、U;第2组为Cr、Ti、Zr、As、F、P;第3组为B;第4组为S、Se。第1组元素的活性性强,其溶出明显受常量组分Ca、Mg、K、Na、Al的控制;第2组元素的溶出受Fe控制;第3组元素B的溶出受Si控制。5.随着淋滤土层的增加,两条土柱淋出液pH值均有增加的趋势,推测与Al的大量活化溶出有关。实验结果表明,研究区土壤酸性强,模拟酸雨可导致深层土壤中Al大量活化,存在生态灾害的风险。
[Abstract]:Longhai City, Zhangzhou City, Fujian Province, is located on the southeast coast of China and is one of the major acid rain areas in China. It is located in the subtropical monsoon climate with abundant rainfall. In addition, frequent acid rain deposition resulted in a large amount of leaching of soil nutrient elements (such as Caomg, MgK, Na, etc.) and strong acidity in the soil. Further acidification may lead to the activation and dissolution of heavy metals, aluminum and other chemical elements in natural media such as soil and rock, thus affecting the growth and development of crops. The quality of water environment has great ecological risk. In this paper, two representative sites in Longhai City are selected to collect soil column profiles, and the simulated acid rain leaching experiments are carried out, and the following understanding is obtained: 1. In the study area, the weathering degree of soil is high, and the leaching of major elements (CaOMg-Knna) is relatively rich in Al, and the weathering degree of soil reaches the stage of desilication and aluminum-rich. The distribution of trace elements in the profile is often controlled by constant elements. The concentration of dissolved elements increased with the increase of leaching fluid acidity and increased with the deepening of leaching soil layer, and the concentration of most elements in soil leachate decreased gradually with the successive advance of leaching experiment. The constant element concentration in leaching solution can be divided into three groups according to its soil-solution partition coefficient and the longitudinal distribution characteristics of leaching solution concentration: the first group is Caomg Ko Na; the second group is Alnife; and the third group is SiO2. The activity of the first group was strong, and it was easy to dissolve into the solution during the leaching process, but the activity of the second group was weak. 4. The dissolution rule of trace elements in the leachate showed that it was controlled by the constant component. According to the dissolution concentration of trace elements, they were divided into the following four groups: group 1 was Cuzcdcdcdcdcdcdcdcu, group 2 was CrTiTiOZrAZOFU, group 3 was Bandits, and group 4 was Sassee. The dissolution of the first group of elements was controlled by the constant component Caomg, the dissolution of the second group was controlled by Fe, and the dissolution of the third group of element B was controlled by Si .5.The dissolution of the first group of elements was obviously controlled by the constant component Caomg, the dissolution of the second group of elements was controlled by Fe, and the dissolution of the third group of element B was controlled by Si. With the increase of leaching soil layer, the pH value of the leaching solution of the two soil columns increased, which is related to the large amount of activated dissolution of Al. The results showed that the acidity of the soil in the study area was strong, and the simulated acid rain could lead to a large amount of Al activation in the deep soil, resulting in the risk of ecological disasters.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S153;X517

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