无机—有机混合改良剂对酸性多金属污染土壤的修复效应

发布时间：2018-07-26 11:33

【摘要】：目前,重金属污染土壤的修复方法主要包括物理修复、化学修复和生物修复,其中化学修复通常采用土壤改良剂,通过与土壤中的重金属发生吸附、沉淀、络合等各种反应,改变土壤重金属的赋存形态,从而降低其迁移性与生物有效性。这种原位化学改良方法操作简单、快速有效、费用成本低,适合于我国这种大面积中低度重金属污染土壤的治理。通常情况下,受矿业废水污染的土壤常为酸性多金属污染土壤,由于不同改良剂对不同重金属的作用机理和效果不同,单一改良剂通常难以达到很好的综合治理目标。因此,筛选出效果好、成本低、持效时间更长的混合改良剂显得尤为重要。本论文试图通过盆栽试验和田间试验,筛选出适合于治理受广东省韶关市大宝山矿业活动污染的酸性多金属污染土壤的无机-有机混合改良剂,为今后该地区的酸性多金属污染土壤的原位化学改良技术提供修复材料和理论依据。本论文取得的主要研究结果如下:(1)在盆栽试验中,“石灰+沸石+磷酸盐+有机肥”无机-有机混合改良剂处理土壤后,土壤pH值显著增加,土壤中Cd、Pb、Cu、Zn有效态浓度显著降低;土壤可交换态Cd、Pb、Cu、Zn含量所占比例显著降低,铁锰氧化物结合态Cd、Pb、Cu、Zn含量所占比例显著升高,土壤中重金属的生物有效性大大降低,从而有效减少了植物对重金属的吸收。其中钙镁磷肥对酸性多金属污染土壤的改良效果比磷矿粉更佳。(2)在田间试验中,混合改良剂能够显著提高土壤pH值和降低土壤中Cd、Pb、Cu、Zn有效态含量,油麦菜能够在改良后的土壤上健康生长,其产量显著提高,其中无机-有机混合改良剂剂比无机混合改良剂效果更佳,磷矿粉在改良土壤的实际应用更为经济且更具有长效性。6种无机-有机混合改良剂中,“石灰石+沸石+磷矿粉+有机肥”的混合改良剂更具有应用前景。土壤改良后,油麦菜地上部的Cd、Cu、Zn含量达到国家食品标准,Pb含量在改良后显著降低,但仍超出国家食品标准的上限值。因此,要保障蔬菜作物在大宝山周边的酸性多金属污染土壤上的安全生产,还需要配合种植Pb低累积作物来实现。(3)高通量测序分析发现,大宝山矿区酸性多重金属污染土壤中的微生物的优势菌种主要有变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、硝化螺旋菌门(Nitrospirae)等。混合改良剂能够显著提高土壤中微生物的活性、丰富度和物种多样性。改良后的土壤中变形菌门的相对丰度有所降低,酸杆菌门的相对丰度显著提高,不同的改良剂对土壤微生物群落结构和多样性的影响存在较大差异。
[Abstract]:At present, remediation methods of heavy metal contaminated soil mainly include physical remediation, chemical remediation and bioremediation. Among them, chemical remediation usually uses soil modifier, through adsorption, precipitation, complexation and other reactions with heavy metals in soil. To reduce the migration and bioavailability of heavy metals in soils by changing their occurrence forms. This in situ chemical improvement method is simple, rapid and effective, and low cost, which is suitable for the treatment of heavy metal contaminated soil in large area of our country. In general, the soil polluted by mining wastewater is usually acidic polymetallic soil. Because different modifiers have different mechanism and effect on different heavy metals, it is difficult for single modifier to achieve the goal of comprehensive treatment. Therefore, it is very important to screen out the mixed modifier with good effect, low cost and longer lasting time. Through pot experiment and field experiment, this paper tries to select the inorganic organic mixed modifier suitable for the treatment of acidic polymetallic contaminated soil polluted by mining activities in Shaoguan City, Guangdong Province. This paper provides the remediation materials and theoretical basis for the in situ chemical improvement of acidic polymetallic contaminated soils in this area. The main results obtained in this paper are as follows: (1) in pot experiment, the pH value of soil increased significantly and the available concentration of CdPbPbCuZn in soil decreased significantly after the treatment of "Lime zeolite Phosphate Organic Fertilizer" inorganic organic mixed modifier; The content of Cu ~ (+) Zn in exchangeable CD ~ (2 +) Pb ~ (2 +) ~ (2 +) decreased significantly, and the proportion of Fe ~ (2 +) -manganese oxide bound CD ~ (2 +) Pb ~ (2 +) Cu ~ (2 +) Zn increased significantly, and the bioavailability of heavy metals in soil decreased greatly, which effectively reduced the absorption of heavy metals by plants. The effect of calcium magnesium phosphate fertilizer on the improvement of acidic polymetallic contaminated soil was better than that of phosphate rock powder. (2) in the field experiment, the mixed modifier could significantly increase the pH value of soil and reduce the available state content of CdPbPbCU Zn in soil. Oatmeal can grow healthily in the improved soil, and its yield is significantly increased. The effect of inorganic organic modifier is better than that of inorganic mixed modifier. The application of phosphate rock powder in improving soil is more economical and has a long term effect of 6 kinds of inorganic organic mixed modifier, and the mixture of "limestone zeolite phosphate rock powder organic fertilizer" has more application prospect. After soil improvement, the content of CD ~ (2 +) ~ (2 +) Cu ~ (2 +) in the aboveground part of oatmeal was significantly lower than that of the national food standard, but it still exceeded the upper limit of the national food standard. Therefore, in order to ensure the safe production of vegetable crops in acidic polymetallic contaminated soils around Dabaoshan, it is also necessary to cooperate with the cultivation of low-accumulation Pb crops. (3) High-throughput sequencing analysis shows that, The dominant microbes in the soil contaminated by many heavy metals in Dabaoshan mine are mainly Proteus, (Proteobacteria), actinomycetes, (Acidobacteria), actinomycetes, (Actinobacteria), (Bacteroidetes), (Bacteroidetes), Helicobacter nitrificans, (Nitrospirae), and so on. The mixed modifier can significantly improve the microbial activity, richness and species diversity in soil. The relative abundance of Proteus in the improved soil was decreased, and the relative abundance of acidobacterium was significantly increased. The effects of different modifiers on the structure and diversity of soil microbial community were different.
【学位授予单位】：华南农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X53

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