铅锌矿区蜈蚣草富集砷过程与机理研究

发布时间：2018-01-14 19:10

本文关键词：铅锌矿区蜈蚣草富集砷过程与机理研究　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：随着矿产资源的开发利用,矿山开采带来的砷污染问题日益突出。开采过程中进入土壤的砷可以通过食物链进入人体,危害人类健康。土壤砷污染治理显得尤为重要。砷超富集植物蜈蚣草的发现,为土壤砷污染的治理提供了新思路。因此,研究蜈蚣草超富集砷的机理,可以为土壤砷污染的植物修复技术提供理论依据。本文以云南铅锌矿区蜈蚣草、凤尾草、华南毛蕨和芒萁及其生长环境为研究介质,调查了矿区污染问题,并针对As超富集植物蜈蚣草体内AsV到AsIII还原位置不确定以及蜈蚣草解毒机理不明的问题,开展了微区、形态和亚细胞提取的实验。其中,通过同步辐射微区XRF技术,重点开展了As与K、Mn、Fe、Cu、Zn、S的微区分布实验。通过X射线近边结构吸收光谱(XANES)技术,重点研究了蜈蚣草根状茎、茎、叶中As的形态。通过亚细胞提取实验,分析了亚细胞层面As在蜈蚣草根茎叶中的形态。具体得到了以下几点结论:(1)矿区土壤的调查结果显示:所调查区域土壤中砷含量均超标,污染最严重点是国家三级质量标准的10.08倍;(2)矿区4种植物的调查结果显示:找到了富集系数和转运系数均大于1的砷超富集植物蜈蚣草和凤尾草,并确定了华南毛蕨和芒萁不是砷超富集植物。(3)微区XRF结果表明:蜈蚣草整体幼苗中As与K、Mn、Fe、Cu、Zn、S的微区分布相似。推测As在地上部(尤其是羽片中)的与除Ca、S外的5种元素的微区分布似乎与植物体内阴阳离子之间的平衡有一定的关系。As与S较好的分布相似性则说明:尽管As和PCs结合的很少,但是PCs在蜈蚣草运输、富集As的过程中很可能扮演着非常重要的作用。(4)XANES结果显示:蜈蚣草根状茎、茎、叶中的As的形态分析,根据根中90%以上为AsV,紧接根和茎的根状茎78.6%为AsIII,茎中87.5%为AsIII,茎到叶的AsIII比例基本不变的实验结果,确定了蜈蚣草中AsV到As III转化的主要为位置为紧接根和茎的根状茎。(5)蜈蚣草根茎叶中砷的亚细胞形态提取结果表明:蜈蚣草叶中疏水蛋白结合态的砷仅占叶中总砷的2.4%,并推测蜈蚣草主要将As储存在了叶中的液泡中,从而达到解毒的目的。
[Abstract]:With the development and utilization of mineral resources, arsenic pollution caused by mining is becoming more and more serious. Arsenic entering the soil can enter the human body through the food chain. The discovery of arsenic super-enriched plant Pteris vittata has provided a new idea for the treatment of soil arsenic pollution. Therefore, the mechanism of super-enrichment of arsenic in Pteris vittata is studied. It can provide theoretical basis for the phytoremediation technology of arsenic pollution in soil. In this paper, the pollution problems in the mining area were investigated by using Pteris vittata, Pteris pondera, Dryopteris chinensis, Osmunda and Osmunda and their growing environment as the research medium. Aiming at the uncertainty of the AsV to AsIII reduction position and the detoxification mechanism of Pteris vittata, the microregion, morphology and subcell extraction experiments were carried out. Through synchrotron radiation (XRF) technique, the experiments on the distribution of as and K _ (mn) Fe _ (Cu) Zn ~ (2 +) S were carried out, and the X-ray near edge structure absorption spectrum (XANES) technique was used. The morphology of as in rhizome, stem and leaf of Pteris vittata was studied. The morphology of as at subcellular level in the stem and leaf of grass root of centipede was analyzed. The following conclusions were obtained: the arsenic content in the soil of the mining area was higher than the standard. The most serious pollution is 10.08 times of the national third-level quality standard; 2) the investigation results of four species of plants in the mining area showed that the enrichment coefficient and transport coefficient were more than 1. The results of XRF showed that as and K _ (mn) Fe _ (Cu) Zn in the whole seedlings of Pteris vittata were not arsenic super-enriched plants. The microdistribution of S is similar. It is inferred that as and Ca removal in the shoot (especially in the plume). The microdistribution of the five elements outside S seems to be related to the balance between anion and anion in plants. The similarity of distribution between as and S suggests that although there are few as and PCs binding. However, PCs may play a very important role in the transportation and enrichment of as in Pteris vittata. The results of XANES showed that the morphological analysis of as in the rhizome, stem and leaf of Pteris vittata. According to the experimental results, more than 90% in the root is ASV, 78.6% in the rhizome and stem is ASIII, 87.5% in the stem is AsIII, and the AsIII ratio between stem and leaf is almost unchanged. The transformation of AsV to as III in Pteris vittata was mainly located in the rhizome. The results of subcellular morphology extraction of arsenic from the stems and leaves of Centipede showed that the hydrophobic protein bound arsenic in the leaves of Pteris vittata was only 2.4% of the total arsenic in the leaves. It is inferred that Pteris vittata mainly stores as in the vacuoles of leaves to detoxify.
【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】：2017
【分类号】：X753;X173

【相似文献】