矿区土壤-小麦重金属迁移特征模拟研究

发布时间：2018-07-10 04:19

本文选题：矿区 + 土壤-小麦　；参考：《中国矿业大学》2017年硕士论文

【摘要】：矿产资源开发利用改变了区域生态系统的物质循环和能量流动,造成了严重的生态破坏和环境污染。其中,矿区土壤重金属污染是严重的问题之一。论文设计并实施2014、2015、2016年三期野外自然条件下的矿区土壤-小麦重金属迁移模拟实验,分析Cr添加场地、Pb添加场地、Zn添加场地和正常对照场地3种添加重金属Cr、Pb、Zn和2种常见重金属Cd、Cu在土壤-小麦系统中的迁移、富集特征。研究可为矿区土壤环境质量改善和粮食安全调控提供数据基础和理论依据。主要结论如下:(1)基于野外模拟实验的基础数据,分析了矿区土壤-小麦重金属迁移、富集特征。①四类场地土壤5种重金属随时间的变化规律存在差异,小麦中5种重金属含量大体先减后增。②添加重金属Cr、Pb、Zn在土壤和小麦中含量数据的离散程度均要大于Cd、Cu。③三类添加场地土壤和小麦中Cr、Pb、Zn均高于正常对照场地,说明人为添加重金属行为直接或间接地促进了重金属元素向土壤-小麦系统中转化和迁移。④三类添加场地土壤Cr、Pb、Zn存在由含量高处向含量低处迁移的现象,符合溶质运移规律。⑤四类场地小麦对Zn的富集能力最强、Pb的富集能力最弱。(2)建立了矿区土壤-小麦重金属迁移模型,并对徐州柳新矿区进行数值模拟。①四类场地土壤-小麦中重金属含量间绝大部分相关系数|r|0.5、灰色度fG(r)0.5,并不存在简单的线性相关关系。②四类场地土壤和小麦中重金属含量的最优曲线回归模型以二次曲线模型和抛物线模型居多。Zn和Cu曲线回归模型的相关性较显著,而Cr、Pb、Cu曲线回归模型的相关性不显著。除Cr以外,正常对照场地重金属曲线回归模型的相关系数岁要高于其他三种添加场地。③小麦中5种重金属的作物富集因子PAF与土壤相应重金属浓度数学模型的相关系数R2均大于0.5,说明两者之间的相关性显著,建立的数学模型可行。其中,小麦中Cd的PAF与土壤重金属Cd浓度数学模型的相关系数R2达到0.918,呈现极显著相关性。④优选的分配估计模型对徐州柳新矿区煤矸石复垦场地、粉煤灰复垦场地和对照场地小麦中Cr的预测效果相对较好、Cd的预测效果相对较差。(3)首先,评价了土壤-小麦系统中重金属生态危害程度,四类场地土壤-小麦中5种重金属总体处于轻度污染水平。在此基础上,设计并实施矿区土壤重金属Cr、Pb、Zn修复植物筛选实验,为矿区土壤重金属污染提供了一种修复植物筛选办法,并初步得出百喜草和狗牙根可做为土壤Cr的修复植物,苜蓿和落花生可做为土壤Pb的修复植物,东南景天和佛甲草对土壤Zn的修复效果不明显。
[Abstract]:The exploitation and utilization of mineral resources have changed the material circulation and energy flow of the regional ecosystem and caused serious ecological damage and environmental pollution. Among them, soil heavy metal pollution is one of the serious problems in mining area. This paper designs and implements a simulation experiment of heavy metal transport between soil and wheat in mining area under three natural conditions in the field in 2014, 2015 and 2016. The migration and enrichment characteristics of three kinds of heavy metals, CrPbPbZn and two common heavy metals, CD and Cu, in the soil-wheat system were analyzed. The study can provide data basis and theoretical basis for soil environmental quality improvement and food security control in mining area. The main conclusions are as follows: (1) based on the basic data of field simulation experiments, the changes of five heavy metals over time in soil and wheat in mining area were analyzed. The contents of 5 kinds of heavy metals in wheat decreased first, then increased 2. 2 in soil and wheat. The dispersion of the data of CRPbZn in soil and wheat was higher than that in the soil of three kinds of addition sites of CdCu.3 and in wheat, which was higher than that in normal control sites. The results showed that anthropogenic addition of heavy metals directly or indirectly promoted the transformation and migration of heavy metal elements into soil-wheat system. In accordance with the solute migration rule, wheat has the strongest enrichment ability of Zn and the weakest enrichment ability of Pb. (2) the heavy metal migration model of soil-wheat in mining area was established. Numerical simulation of Xuzhou Liuxin mining area. 1.Most correlation coefficient of heavy metal content between soil and wheat in four kinds of sites is r 0.5, grey degree fG (r) 0.5. There is no simple linear correlation between soil and wheat in four types of sites. The correlation between the quadratic curve model and the parabola model was significant in the optimal curve regression model of heavy metal content. The correlation between the curve regression model and the Cu curve regression model was significant. However, there was no significant correlation between the curve regression model of CrPbCU and Cu. Except for Cr, The correlation coefficient of curve regression model of heavy metals in normal control site was higher than that of the mathematical model of soil heavy metal concentration and PAF of 5 heavy metals in the other three kinds of wheat. 3. The correlation coefficient R2 of PAF was higher than that of the mathematical model of soil concentration of heavy metals. All of them are more than 0.5, which means that there is a significant correlation between them. The established mathematical model is feasible. Among them, the correlation coefficient R2 between PAF of CD in wheat and CD concentration in soil reached 0.918, which showed highly significant correlation. 4 optimal allocation estimation model for coal gangue reclamation site in Xuzhou Liuxin mining area. The prediction effect of Cr and CD in fly-ash reclamation site and control field was relatively good. (3) the ecological damage degree of heavy metals in soil-wheat system was evaluated. Five kinds of heavy metals in four kinds of soil-wheat were in the level of light pollution. On the basis of this, the screening experiment of remediation plants for heavy metal Cr Pb Zn in the soil of mining area was designed and carried out, which provided a method for the screening of remediation plants for heavy metal pollution in the soil of mining area, and it was preliminarily concluded that Bahia grasses and Doggeana could be used as remediation plants for soil Cr. Alfalfa and peanut can be used as soil Pb remediation plants.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S512.1;X53;X751

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