有机氯农药污染土壤生物学特性及降解效应研究

发布时间：2018-04-14 15:19

本文选题：污染场地 + 有机氯农药　；参考：《清华大学》2015年博士论文

【摘要】：工业污染场地污染特征的识别对于设计、实施及评价土壤污染治理具有重要的基础意义。本文系统研究了农药厂搬迁场地土壤环境中的有机氯农药等典型有机类污染物的赋存特征,揭示了有机氯农药污染生物学特性、土著植物根围和根际效应及其与环境因子之间的关系,考察了不同生物强化过程中土壤中HCHs/DDTs去除效果及微生物群落结构的动态演化。本研究中,在污染表层土壤中检测出18种有机氯农药,其中HCHs和DDTs检出率为100%,其最高浓度为国家标准4-5个数量级,植物组织样品中的HCHs和DDTs的检出率在95%以上。根围土壤中污染物的浓度显著低于裸露土壤,差别为1-2个数量级。污染物沿土壤剖面分布的分析结果表明DDTs和HCHs存在深层迁移的风险。测定了有机氯污染土壤样品中的土壤酶活、功能基因(lin A和RDH-like)、微生物群落结构及多样性,结果表明:土壤中的微生物群落结构和多样性随着污染水平的升高而降低;同一污染水平下植物生长促进了微生物多样性;lin A基因的丰度随着污染水平升高而提高;植物根际区RDH-like和lin A基因的丰度为裸露土壤的3倍。采用多元统计分析方法确定了污染土壤中微生物群落和多样性的特征,揭示了HCHs和DDTs、土壤理化因子和植物生长等对不同采样点的土壤微生物群落的影响规律。采用微生物与植物协同降解有机氯农药,考察了不同实验条件下的降解效果以及土壤中微生物群落的演化特征。经过90天的降解,土壤中HCHs和DDTs最高去除率分别达到81%和85%左右。对微生物群落结构、多样性、Kocuria sp.P5和lin A基因的分析结果表明植物生长区形成了独特的微生物类群,说明农药污染和环境胁迫对微生物群落结构的重塑性具有重要作用。
[Abstract]:The identification of the pollution characteristics of industrial pollution sites is of fundamental significance for the design, implementation and evaluation of soil pollution control.In this paper, the occurrence characteristics of typical organic pollutants such as organochlorine pesticides in the soil environment of the relocation site of the agricultural pharmaceutical factory were systematically studied, and the biological characteristics of organochlorine pesticide pollution were revealed.The effects of root circumference and rhizosphere of indigenous plants and their relationship with environmental factors were studied. The removal efficiency of HCHs/DDTs in soil and the dynamic evolution of microbial community structure during different biofortification were investigated.In this study, 18 organochlorine pesticides were detected in contaminated topsoil. The detectable rate of HCHs and DDTs was 100 and the highest concentration was 4-5 orders of magnitude of national standard. The detection rate of HCHs and DDTs in plant tissue samples was more than 95%.The concentration of pollutants in root soil was significantly lower than that in exposed soil, with a difference of 1-2 orders of magnitude.The distribution of pollutants along soil profile showed that DDTs and HCHs had the risk of deep migration.The soil enzyme activity, the functional genes of catalin-A and RDH-like, the structure and diversity of microbial community in organochlorine contaminated soil samples were determined. The results showed that the structure and diversity of soil microbial community decreased with the increase of soil pollution level.Under the same pollution level, plant growth promoted the abundance of RDH-like A gene in microbial diversity, and the abundance of RDH-like and lin A genes in the rhizosphere of plants increased with the increase of pollution level. The abundance of RDH-like and lin A genes in the rhizosphere was 3 times higher than that in exposed soil.The characteristics of microbial community and diversity in polluted soil were determined by multivariate statistical analysis, and the effects of HCHs and DDTs, soil physicochemical factors and plant growth on soil microbial community at different sampling points were revealed.The biodegradation of organochlorine pesticides (OCPs) by microbes and plants was studied under different experimental conditions and the evolution characteristics of microbial communities in soil were studied.After 90 days of degradation, the highest removal rates of HCHs and DDTs in soil reached 81% and 85% respectively.The analysis of microbial community structure, Kocuria sp.P5 and lin A gene showed that the plant growth region formed a unique microbial community, indicating that pesticide pollution and environmental stress play an important role in the remodeling of microbial community structure.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X53;X592

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