【作者】 马传鑫；

【导师】 汪志荣；

【作者基本信息】 天津理工大学 ， 环境科学， 2011， 硕士

【摘要】 随着石油开采量和使用量的增加,石油不可避免的进入土壤环境,形成石油污染土壤。当石油进入土壤环境后,会改变土壤的理化性质,导致土壤通透性降低,同时,作为复杂化合物,其中芳香族化合物,特别是PAHs具有“三致”效应,对土壤中动物、植物及微生物造成严重威胁。植物-微生物作为一种快速、高效且不具有二次污染的处理方法,已经被普遍应用于石油污染土壤修复。结合天津市土壤盐碱化特点,采用植物-微生物联合修复的方法研究石油污染土壤的降解效率为原位土壤修复提供理论基础。通过设定含盐量2493mg/kg、3690mg/kg和4666.67mg/kg,含油量5000 mg/kg、10000 mg/kg和15000mg/kg,研究对土壤中石油污染物的去除,可以得出以下结论:通过对比分析非根系、植物和植物-微生物联合修复发现对于含油量5000mg/kg盆栽土壤,植物修复<非根系土壤<植物-微生物联合修复;对于含油量10000mg/kg和15000mg/kg盆栽土壤,植物修复≈非根系土壤<植物-微生物联合修复。研究不同条件下土壤中微生物数量和脱氢酶活性表明,在有植物作用的情况下,土壤中微生物数量到达峰值的时间要明显比非根系土壤推迟,同时,微生物数量亦高于非根系土壤。在高含盐量条件下,土壤中微生物数量明显受到抑制,这一结果在测定脱氢酶过程中亦有所体现。通过对盆栽土壤中微生物进行形态学结构分析,初步鉴定土壤中微生物菌群可分为10个属:芽孢杆菌属(12.8%)、芽孢乳杆菌属(38.5%)、葡萄球菌属(10.3%)、气球菌属(5.1%)、节杆菌属(12.8%)、盐芽孢杆菌(5.1%)、乳杆菌属(2.6%)、梭菌属(2.6%)、链球菌属(2.6%)和微球菌属(5.1%)。研究植物各项生理指标表明在含盐量4666.67mg/kg条件下,供试植物苜蓿的发芽率、株高、生物量和根长等明显受到抑制。同时对比分析植物根系活力发现,在有外源微生物菌群作用的条件下明显高于单一植物作用。通过研究高盐条件下细菌和真菌菌群对石油降解效果,并同时测定摇瓶中微生物数量、酶活性、pH及微生物群落多样性(PCR-DGGE)可以得到以下主要结论:石油在细菌和真菌菌群作用下的降解规律为:含油量30000>含油量10000>含油量50000。同时,通过平板计数研究微生物数量随时间变化发现,细菌数量明显高于真菌在各个时期的数量,反映到菌液中脱氢酶活性上亦可得到相似的结论,这在一定程度上可以解释细菌菌群中石油降解率明显高于真菌菌群的原因。在不同时期测定细菌和真菌菌群中pH变化发现,随着时间的推移摇瓶中pH呈现了弱碱性,需从菌群生长和代谢过程入手,找出具体原因。通过PCR-DGGE分析,可以发现无论细菌菌群还是真菌菌群,随着摇瓶中含油量的增加,体系中优势条带增多且强度增强,同时,菌群中其它条带增多,说明菌群多样性增加,结构更加复杂。更多还原

【Abstract】 With increased yield and consumption of crude oil, it is inevitable to enter soil environment and to contaminate the soil. Once crude oil mixing with soil, the physical and chemical characters of soil will be changed and permeability of the soil voids will be blocked. Meanwhile, as a complex compound, aromatic compounds in the crude oil take a large proportion, especially for PAHs, which can cause carcinogenic, teratogenic and mutagenic, all of these will run a high risk to animals, plants and microbes in the soil.Plant-microbial remediation as a fast, efficient and non-secondary pollution treatment has been applied remediation of crude oil contaminated soil commonly. Based on the salinity character of soil in Tianjin, crude oil contaminated soil remediation under high salt concentration by using plant-microbial method can provide theories for restoring in-suit soil directly. In this test, three salt contents, including 2493mg/kg, 3690mg/kg and 4666.67mg/kg, three crude oil contents, including 5000 mg/kg, 10000 mg/kg and 15000mg/kg are designed to study crude oil degradation rate in the pot experiments by applying plant-microbial combined method, the main conclusions are listed:Through comparison of non-root group, plant group and plant-microbe group, it shows that the degradation rate under 5000mg/kg crude oil is plant group<non-root group<plant-microbe group; the degradation rate under 10000mg/kg and 15000mg/kg crude oil is plant group≈non-root group<plant-microbe group.When considering the effect of plant in the whole process of remediation, the time of reaching peak point of the total microbial amount in the soil is delayed comparing with non-root group. Meanwhile, total microbial amount in the soil is higher than that of non-root group. Also, under high salt condition, microbial amount is inhibited, the same results can be found when measuring DHA in the different salt and oil contents.Ten sorts of bacteria in the pot experiment are identified through morphological structure of microbe, including Bacillus(12.8%), Sporolactobacillus(38.5%), Staphylococcus(10.3%), Aerococcus(5.1%), Arthrobacter (12.8%), Halobacillus-spring(5.1%), Lactabacillus(2.6%), Clostridium(2.6%), Strptococcus(2.6%) and Micrococcus(5.1%).Physiological indicators of plant describe that germination rate, height, biomass and root length of plant are inhibited under the condition of 4666.67mg/kg salt content. Meanwhile, comparing with root activity of plant group, the root activity under the effect of exogenous microbial flora is much higher than plant group.The main conclusions in the crude oil degradation under high salt concentration (7000mg/L) by bacteria flora and fungus flora are:The similar discipline of degradation rate of crude oil can be found in both bacteria flora and fungus flora: 30000mg/L>10000mg/L>50000mg/L. However, the final degradation rate of crude oil in the fungus flora is lower than that of in the bacteria flora. The same conclusions of DHA and total microbial amount in the flask are resulted.It is worth to point out that pH in both bacteria flora and fungus flora has changed greatly from neutral/acidic to alkaline. However, an exact explanation to this phenomenon cannot be concluded now.Through PCR-DGGE analysis, the main strain is increased as crude oil content increasement and the strength of these main strains is increased as well. Meanwhile, the structure and complex of bacteria and fungus flora become more and more diverse as crude oil increasement by observing other stains in each flask system.更多还原