高浓度核素污染土壤修复植物筛选及肥料对植物修复的影响

发布时间：2018-11-20 08:09

【摘要】：随着核能的应用及核技术的发展,核素污染已成为一个日益严峻、亟待解决的问题,锶、铯、铀是较为常见且污染量较大的核素污染物。植物修复是目前具有绿色、经济、有效的修复技术之一,具有广泛的应用前景。本文采用稳定性同位素模拟放射性核素的方式,对锶、铯、铀污染(浓度分别227.47mg·kg-1、234.90mg·kg-1、485.00 mg·kg-1)土壤进行二次修复研究;用反枝苋、红圆叶苋、藜等16种不同科属植物,研究核素对植物的生物效应和植物对核素的富集能力,筛选对锶、铯、铀具有较好耐性及富集能力的植物;采用土壤、铀浓度、N、P、K肥料5因素5水平正交旋转设计,研究这5个因素对蕹菜和菊苣修复能力的影响;在不同铀污染土壤中,研究不同浓度锰、锌、铜、钼、硼微量元素对菊苣实生苗和再生苗修复的影响。本研究的目的是,筛选出对锶、铯、铀污染土壤的耐性和修复效果的植物,筛选出强化植物修复铀污染土壤效果好的施肥种类及用量,为铀污染土壤的植物修复提供理论和方法依据。主要研究结论如下:(1)不同植物修复88Sr、133Cs、238U的能力不同。根据耐性和富集含量,牛皮菜、红圆叶苋、反枝苋可以作为锶污染土壤修复植物,它们的锶含量分别为3435.85 mg·kg-1、2653.21 mg·kg-1、2572.99 mg·kg-1;牛皮菜、反枝苋、菊苣、红圆叶苋、藜可以作为铯污染土壤修复植物,它们的铯含量分别为12706.50mg·kg-1、8429.44 mg·kg-1、7744.50 mg·kg-1、6118.09 mg·kg-1、5930.65 mg·kg-1;酸模、鬼针草、苍耳、向日葵可以作为铀污染土壤修复植物,它们的铀含量分别为363.57 mg·kg-1、91.87 mg·kg-1、75.80 mg·kg-1、65.42 mg·kg-1。(2)不同植物在不同土壤、不同238U污染浓度下,施N、P、K对铀富集的影响有较大差异。施N、P、K对菊苣茎叶238U含量和TF影响不显著;施P或K肥对蕹菜单株238U含量没有显著影响,而N肥有显著的负影响;每kg土壤增施300 mg N,蕹菜铀含量降低9.789 mg·kg-1。(3)微量元素种类和用量对菊苣富集238U的影响不同。铜40 mg·kg-1降低150 mg·kg-1 238U浓度下菊苣实生苗富集238U作用最大,与CK相比降低50.87%,锌100降低100 mg·kg-1 238U浓度下菊苣再生苗富集238U作用最大,与CK相比降低61.52%;硼50 mg·kg-1增加50 mg·kg-1 238U浓度下菊苣实生苗和再生苗富集238U作用最大,与CK相比分别增加186.53%和80.69%。因此,实践中要根据土壤污染核素种类选择适宜的修复植物,要根据铀污染土壤种类和浓度采取适宜的施肥种类和数量,以便有效地提高修复效果。同时,菊苣再生苗的修复能力较强,实践中可以一次播种多次收获,降低修复成本,提高修复效率。
[Abstract]:With the application of nuclear energy and the development of nuclear technology, nuclide pollution has become an increasingly serious and urgent problem. Strontium, cesium and uranium are common and contaminated nuclide pollutants. Phytoremediation is one of the green, economical and effective remediation technologies, and has a wide application prospect. In this paper, the secondary remediation of strontium, cesium and uranium-contaminated soils (concentration of 227.47mg kg-1234.90mg kg-1485.00 mg kg-1) was studied by using stable isotopes to simulate radionuclides. The bioeffects of radionuclides on plants and the enrichment ability of plants to nuclide were studied by using 16 species of different families, including Amaranthus retrograde, Amaranthus rotundifolia, Chenopodium, etc., and plants with good tolerance and enrichment ability to strontium, cesium and uranium were screened. The effects of soil, uranium concentration and NbPK fertilizer on the remediation ability of Ipomoea aquatica and chicory were studied by orthogonal rotation design with 5 factors and 5 levels. Effects of trace elements mn, Zn, Cu, Mo and B on regeneration and regeneration of chicory seedlings were studied in different uranium-contaminated soils. The purpose of this study was to screen out the plants that could tolerate and repair the contaminated soils of strontium, cesium and uranium, and to screen out the kinds and amounts of fertilizer which could be used to restore uranium-contaminated soil by the enhanced plants. It provides theoretical and methodological basis for phytoremediation of uranium-contaminated soil. The main conclusions are as follows: (1) the ability of different plants to repair 88SrA133CsCs238U is different. According to their tolerance and enrichment, Herba canola, Amaranthus rotundifolia and Amaranthus retroglauca can be used as remediation plants for strontium contaminated soil. Their strontium content is 3435.85 mg kg-1,2653.21 mg kg-1,2572.99 mg kg-1;, respectively. The contents of cesium are 12706.50mg kg-1,8429.44 mg kg-1,7744.50 mg kg-1,6118.09 mg kg-1,5930.65 mg kg-1;, which can be used as the remediation plant of cesium contaminated soil, such as Cattleberry, reverse amaranth, chicory, red leaf amaranth and Chenopodium monopodium. Acid molds, nebula, Xanthium and sunflower can be used as remediation plants for uranium-contaminated soil. Their uranium content was 363.57 mg kg-1,91.87 mg kg-1,75.80 mg kg-1,65.42 mg kg-1. (2) different plants in different soils and different concentrations of 238U. The effect of K on uranium enrichment is quite different. There was no significant effect on the content of 238U and TF in stems and leaves of chicory, but no significant effect of P or K fertilizer on 238U content of water spinach per plant, but there was a significant negative effect of N fertilizer on the content of 238U in the stem and leaf of chicory. The effect of 9.789 mg kg-1. (3) trace elements on the enrichment of chicory was different when adding 300 mg N per kg to the soil of Ipomoea aquatica. When Cu 40 mg kg-1 decreased by 150 mg kg-1 238U, the enrichment of Cichory seedlings was the greatest, compared with that of CK, it decreased 50.87U, and that of Zn-100 decreased by 100 mg kg-1 238U. The concentration of Zn-100 decreased by 100 mg kg-1 238U, and the concentration of Zn-100 decreased by 100 mg kg-1 238U. Compared with CK, 61.52% decreased. When boron 50 mg kg-1 was increased by 50 mg kg-1 238U, the enrichment of seedling and regeneration seedlings of chicory was the greatest, which was 186.53% and 80.69% higher than that of CK, respectively. Therefore, it is necessary to select suitable remediation plants according to the types of soil contaminated nuclides in practice, and to adopt appropriate fertilizer types and quantities according to the types and concentrations of uranium-contaminated soils in order to effectively improve the remediation effect. At the same time, the regenerated plantlets of chicory have strong repair ability, which can be harvested many times at a time, reduce the cost of restoration and improve the efficiency of restoration.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X591;X53

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