几种改良剂在重金属复合污染土壤修复中的作用研究

发布时间：2018-02-15 22:32

本文关键词： 土壤改良剂重金属植物生理指标亚细胞　出处：《新疆大学》2015年硕士论文　论文类型：学位论文

【摘要】：土壤重金属污染具有隐蔽性、滞后性、不可逆性和高生物毒性等特点,并能通过食物链传递作用对人体健康构成严重危害。目前我国重金属污染土壤面积已接近可用耕地面积的20%,根据国情开发成本低廉、操作简易、大面积适用的重金属污染土壤治理技术具有重要意义。本文以重金属复合污染土壤为研究对象,以沸石、鸡蛋壳、牡蛎壳、硅藻土、聚丙烯酰胺(PAM)为改良剂,采用单独施加和不同组合加入的方式,通过种植植物进行为期240天的温室盆栽修复试验,研究了改良剂存在条件下重金属Cu、Zn、Ni、Cd、Cr和Pb在土壤-植物系统中迁移转化规律;探讨了改良剂联合植物对重金属污染土壤修复的长效性,考察了改良剂对重金属稳定化效果随时间的变化;分析了加入不同改良剂后土壤中DTPA提取态Cu、Zn、Ni、Cd、Cr和Pb的含量及其形态变化;测定了土壤pH值、植物抗氧化系酶(超氧化歧化酶(SOD)和过氧化氢酶(CAT))、丙二醛(MDA)和H2O2含量的变化,并结合植物亚细胞分布模型对修复后土壤的生态安全进行了生物学性质评价。同时,开展场地微区试验研究,以苏州青为模式植物,考察不同改良剂对重金属复合污染土壤的原位修复效果,并对低积累青菜品种进行了筛选。主要研究结论如下:(1)改良剂的加入显著降低了青菜地上部分Cu、Zn、Ni和Cd的含量,并减少了氧化性损伤和脂膜损伤;同时,施加改良剂处理后,土壤pH值显著提高,提取态Cu、Zn、Pb、Ni和Cd的含量普遍降低(硅藻土处理除外);相关性分析表明,土壤pH值与提取态Pb、Zn、Ni和Cd含量呈显著的负相关,而青菜中Zn、Ni和Cd的含量与土壤提取态含量呈显著正相关。(2)连续种植实验研究结果表明,随着时间的推移,土壤的pH值有所降低,但依然显著高于对照;土壤提取态Cu、Zn、Pb、Ni和Cd含量显著降低(硅藻土处理除外);分级提取结果表明,土壤中Cu、Zn、Pb、Ni、Cr和Cd可交换态含量显著降低(除单独加入硅藻土处理外);茼蒿体内重金属含量呈现不同程度的降低趋势;茼蒿叶中MDA和SOD量有所降低,CAT活性升高,而H2O2含量的变化不显著,Cu、Ni和Cr在植物解毒组分中比例上升进而降低了重金属对植物的毒性。(3)原位修复实验结果表明,不同改良剂处理使得青菜中重金属Cu和Cr含量有不同程度的降低;六种青菜品种筛选结果表明上海青对目标重金属的富集量最少,可推荐作为当地的青菜种植品种。
[Abstract]:Heavy metal pollution in soil is characterized by concealment, lag, irreversibility and high biotoxicity. At present, the heavy metal contaminated soil area in our country is close to 20% of the usable cultivated land area, and the development cost is low and the operation is simple according to the national conditions. The treatment of heavy metal contaminated soil is of great significance. In this paper, zeolite, egg shell, oyster shell, diatomite, polyacrylamide polyacrylamide (PAM) are used as modifiers. A 240 day greenhouse pot experiment was carried out to study the migration and transformation of heavy metals (Cu ~ (2 +) Zn ~ (2 +) ~ (2 +)) ~ (2 +) ~ (2 +) ~ (2 +) ~ (2 +) in the soil-plant system in the presence of the modifier. The long-term effect of the modifier combined with plant on the remediation of heavy metal contaminated soil was studied. The effect of the modifier on the stabilization of heavy metal was investigated with time. The contents of Cr and Pb and their morphological changes in soil with different modifiers were analyzed, and the changes of soil pH, plant antioxidant enzymes (SOD), catalase (cat), malondialdehyde (MDA) and H _ 2O _ 2 (H _ 2O _ 2) were determined. The biological properties of soil ecological security after restoration were evaluated with plant subcellular distribution model. The in situ remediation effects of different modifiers on heavy metal contaminated soil were investigated, and the varieties of green vegetables with low accumulation were screened. The main conclusions were as follows: 1) the addition of the modifier significantly reduced the contents of Cu + Zn + Zn + Ni and CD in the aboveground part of the vegetable. At the same time, the pH value of the soil increased significantly, and the contents of Ni and CD in the extracted form of Cuznznzn PbN were decreased generally (except diatomite treatment), and the correlation analysis showed that, after the treatment of the modifier, the pH value of the soil was significantly increased, and the contents of Ni and CD in the extracted form were generally decreased. The soil pH value was negatively correlated with the contents of Pb ~ (2 +) Zn ~ (2 +) Ni and CD, while the content of Zn ~ (2 +) Ni and CD in green vegetables was positively correlated with the content of soil extract state.) the results of continuous planting experiment showed that the pH value of soil decreased with time. But it was still significantly higher than that of the control, and the contents of Ni and CD in the soil were significantly decreased (except diatomite treatment). The exchangeable state contents of Cu ~ (2 +) Zn ~ (2 +) Pb ~ (2 +) Ni ~ (2 +) Cr and CD in soil decreased significantly (except for diatomite treatment alone), the contents of heavy metals in chrysanthemum chrysanthemum showed a decreasing trend to different extent, and the contents of MDA and SOD in leaves of Chrysanthemum chrysanthemum decreased the activity of cat. However, the change of H _ 2O _ 2 content was not significant. The proportion of Cu _ (2) Ni and Cr in detoxification components increased and then decreased the toxicity of heavy metals to plants. The contents of heavy metals Cu and Cr in green vegetables were decreased by different modifiers, and the results of six varieties of green vegetables showed that Shanghai green had the least concentration of target heavy metals, which could be recommended as local varieties of green vegetables.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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