锌镉污染土壤的田间植物连续修复研究

发布时间：2018-05-10 07:22

  本文选题：锌镉污染土壤 + 田间试验　； 参考：《贵州大学》2015年硕士论文

【摘要】：重金属污染土壤植物修复技术因其固有的优越性而具有广泛的应用潜力,但该技术应用往往需要多次种植植物进行连续修复。修复过程中土壤重金属和植物吸收重金属变化将显著影响修复效率,且较长修复时间与农田土壤利用相矛盾。本论文以有色金属冶炼以及污泥有机肥长期农用导致的重金属污染土壤为对象,利用锌镉超积累植物伴矿景天(Sedum plumbizincicol a)及农作物开展田间连续修复和水分模拟试验,探讨长期田间连续修复下污染土壤锌镉和植物锌镉变化特征;探索适宜的生产和修复同时进行的种植模式和水分调控措施,为锌镉污染土壤进行安全生产的同时实现高效吸取修复提供理论依据。主要研究结果如下:1.连续八年开展伴矿景天与玉米(或高粱)套作田间试验,探讨长期修复下植物及土壤中锌镉变化。结果表明,田间长期原位修复能显著降低农田土壤的锌镉浓度,其中套作处理下土壤镉浓度从3.50±0.49 mg kg-1降低到0.55±0.44 mg kg-1,从而使土壤中镉低于国家土壤环境质量(GB15618-1995)三级标准。与2006年未修复土壤相比,玉米(高粱)单作、伴矿景天单作、玉米与伴矿景天间作处理,对污染土壤中锌镉的总去除修复效率分别达7.2,13.7,18.8%;40.9,71.9和85.4%,即伴矿景天与玉米间作可提高植物吸取修复效率,且玉米籽粒中镉浓度符合国家食品安全标准,可实现污染土壤的“边生产边修复”。2.在污泥有机肥长期农用土壤上种植伴矿景天,与常规的玉米-小麦-胡萝卜轮作处理比较,田间试验探讨了污泥有机肥长期施用导致的重金属污染土壤上农产品的污染风险和连续植物修复效率。结果表明,长期污泥农用土壤上农作物和超积累植物生长良好。与对照相比,“玉米-小麦-胡萝卜轮作”处理作物中锌镉浓度有所上升,且小麦、胡萝卜中镉浓度超过国家食品安全标准。伴矿景天处理下土壤中重金属显著降低,修复效率达到56.0%,而继续施用污泥情况下超积累植物的修复效率仍可达48.0%。证明在施用污泥条件下,种植伴矿景天和玉米,能够实现污泥安全处理、促进农作物生长和超积累植物高效修复的三重目标。3.土壤水分变化可显著改变土壤性质进而影响土壤重金属有效性。本试验通过测定土壤溶液和采用薄层凝胶梯度法(DGT)表征的水分变化过程中土壤重金属有效性的变化特征。结果表明,土壤干燥可显著降低DGT表征的重金属有效性。在农业生产中可通过适当水分管理措施改变土壤重金属的有效性,从而调节农作物和超积累植物对重金属吸收。
[Abstract]:The phytoremediation technology of heavy metal contaminated soil has wide application potential because of its inherent advantages, but the application of this technique often requires the continuous remediation of plants planted many times. The changes of heavy metals uptake by soil and plants during remediation will significantly affect the remediation efficiency, and the longer remediation time is contradictory to the utilization of farmland soil. In this paper, the heavy metal contaminated soil caused by non-ferrous metal smelting and sludge organic fertilizer for a long time was used to carry out continuous remediation and water simulation experiments in the field by using Zn and CD superaccumulative plant plumbizincicol a and crops. To explore the variation characteristics of Zn and CD in contaminated soil and plants under long-term continuous remediation in the field, and to explore the suitable planting mode and water control measures at the same time of production and remediation. It provides a theoretical basis for the safe production of zinc and cadmium contaminated soil and the realization of high efficiency absorption and remediation at the same time. The main results are as follows: 1. For eight consecutive years, a field experiment was carried out to study the changes of Zn and CD in plant and soil under long-term remediation with maize (or sorghum). The results showed that long-term in situ remediation could significantly reduce the concentration of Zn and CD in farmland soil. The soil cadmium concentration decreased from 3.50 卤0.49 mg kg-1 to 0.55 卤0.44 mg kg-1 under intercropping treatment, which resulted in the cadmium in soil lower than the third grade standard of National soil Environmental quality (GB15618-1995). Compared with the unrepaired soil in 2006, the maize (sorghum) monoculture, the intercropping of maize and the intercropping of the mined-linked Jingtian were treated. The total removal and remediation efficiency of Zn and CD in contaminated soil were 7.2 ~ 13.718.8% ~ 40.9 ~ 71.9 and 85.4, respectively. That is, the intercropping of Jingtian and corn could improve the recovery efficiency of plant absorption, and the cadmium concentration in corn grain was in line with the national food safety standard, and the total remediation efficiency of Zn ~ (2 +) and CD ~ (2 +) in maize grain was in accordance with the national food safety standard. Can achieve contaminated soil "production while remediation". 2. Compared with the conventional maize, wheat and carrot rotation treatment, the soil planted with sludge organic fertilizer for a long period of time in agriculture was compared with the conventional maize, wheat and carrot rotation treatment. Field experiments were conducted to investigate the risk of agricultural products pollution and the efficiency of continuous phytoremediation of heavy metal contaminated soil caused by long-term application of sludge organic fertilizer. The results showed that the crops and super-accumulative plants grew well on the soil of long-term sludge. Compared with the control, the concentration of Zn and CD in the maize, wheat and carrot rotation increased, and the cadmium concentration in wheat and carrot exceeded the national food safety standard. The heavy metals in the soil decreased significantly and the remediation efficiency reached 56.0 under the treatment of Jingtian mine, but the remediation efficiency of the superaccumulative plants was still 48.0 under the condition of continued application of sludge. It was proved that under the condition of sludge application, the triple target of high efficiency remediation of crops growth and superaccumulation could be achieved by planting Jingtian and maize. The change of soil moisture can significantly change the properties of soil and then affect the availability of heavy metals in soil. In this experiment, the characteristics of the availability of heavy metals in soil were determined by means of soil solution and TLC Gel gradient method (TGG). The results showed that soil drying could significantly reduce the availability of heavy metals characterized by DGT. In agricultural production, the availability of heavy metals in soil can be changed by appropriate water management measures, thus regulating the absorption of heavy metals by crops and superaccumulative plants.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X173
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本文编号：1868372