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生物表面活性剂强化微生物修复多环芳烃污染土壤的初探 总被引:8,自引:0,他引:8
通过温室盆栽实验,单独或联合接种多环芳烃专性降解菌(DB)和添加生物表面活性剂-鼠李糖脂(RH),研究了生物表面活性剂强化微生物修复多环芳烃(PAHs)长期污染土壤的效果。结果表明,添加RH和接种DB能明显促进土壤中PAHs总量和各组分PAHs的降解。经过90 d培养后,添加RH、DB和RH+DB处理的PAHs的降解率分别为21.3%、32.6%、36.0%,较对照分别提高了333.0%、563.3%、633.0%。此外,随着苯环数的增加,土壤中15种PAHs平均降解率逐渐降低。同时也发现DB、RH+DB处理土壤中脱氢酶活性、多酚氧化酶活性和PAHs降解菌数量显著高于CK、RH处理,但是CK与RH处理没有显著差异,说明DB、RH在促进土壤中PAHs的降解方面有不同的机制。 相似文献
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多环芳烃污染土壤的植物-微生物联合修复初探 总被引:4,自引:1,他引:3
在温室盆栽条件下,通过种植紫花苜蓿单独或联合接种菌根真菌(Glomus caledonium L.)(AM)和多环芳烃专性降解菌(DB),研究了利用植物-微生物强化修复多环芳烃(PAHs)长期污染土壤的效果。试验结果表明,接种菌根真菌和PAHs专性降解菌能促进紫花苜蓿的生长和土壤中PAHs的降解。经过90天修复试验,种植紫花苜蓿接种AM、DB和DB+AM处理的PAHs的降解率分别为47.9%、49.6%、60.1%,均高于只种植紫花苜蓿的对照处理(CK)(21.7%)。另外,随着PAHs苯环数的增加,其平均降解率逐渐降低,但是接种PAHs专性降解菌能够提高4环和5环PAHs的降解率。同时也发现土壤中脱氢酶活性和PAHs降解菌数量越高的处理,土壤PAHs的降解率也越高,这也是种植紫花苜蓿接种微生物能够有效促进土壤PAHs降解的原因。 相似文献
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腐殖酸与活性污泥对污染土壤联合修复研究 总被引:1,自引:0,他引:1
采用正交试验的方法,研究了表面活性剂溶出和微生物降解联合作用对重金属铜、锌、铅和多环芳烃菲、萘、芘人工老化污染土壤的修复效率。选择腐殖酸为表面活性剂,强化微生物对有机污染物的降解性能,将高效降解菌的降解能力有效地发挥出来;用驯化的活性污泥为土壤生物修复剂,强化腐殖酸对重金属的洗提作用,旨在降低重金属和多环芳烃在土壤中的污染作用,提高修复效率。结果表明,接种2.0%活性污泥,温度为35℃,pH值为6.5,腐殖酸加入量为5mg/g的土壤为最佳修复条件,在此条件下菲、萘、芘的总修复率分别为73.4%,80.5%和68.2%;重金属离子Cu2+,Zn2+,Pb3+的总修复率分别为75.5%,64.2%和71.7%。添加腐殖酸和驯化活性污泥可明显提高土壤中重金属和多环芳烃的修复效率,表明化学溶出与生物降解同时作用于复合污染土壤具有较好的协同作用。 相似文献
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多环芳烃长期污染土壤的微生物强化修复初步研究 总被引:16,自引:5,他引:16
本研究通过室内模拟试验,以急性毒性较强的菲(Phe)和遗传毒性较强的苯并[a]芘(B[a]P)为代表性多环芳烃(PAHs)污染物,以不同C源、通气状况和水分条件为调控因子,对PAHs长期污染土壤的土著微生物强化修复进行初步研究。结果表明,搅动处理使污染土壤中Phe和B[a]P的降解率分别达59.44%和26.14%,而淹水处理使两者降解率分别达46.48%和13.27%。添加C源(淀粉和葡萄糖)处理提高了土壤中PAHs的降解率,且随着C源的施用量而增加。同时也发现污染土壤中PAHs降解菌和微生物总量呈正相关,并随着PAHs降解菌数量的增加,土壤中PAHs降解率也随之提高。可见,土壤中PAHs降解速率主要决定于PAHs的降解菌数量。 相似文献
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多环芳烃类有机污染物在土壤中可长期存在,进而通过食物链对人类健康产生重大潜在风险。对多环芳烃污染土壤进行植物修复是一种环境友好且经济有效的污染补救策略。进行植物根际效应机制研究对于开发可持续性多环芳烃污染土壤的植物修复技术具有重要指导意义。对近年来的相关研究工作进行了总结,结果表明:多种禾本科植物具有较强的多环芳烃污染耐受性和较好的修复效能,利用多植物混植的联合修复方式表现出优于单一植物的修复优势。低分子量有机酸类根系分泌物通过与土壤中多环芳烃污染物形成反馈回路决定植物修复体系中多环芳烃的命运。修复植物根系分泌物可塑造特定的根际微生物区系,根际微生物可通过多种机制来降解土壤环境中的多环芳烃。针对在植物修复多环芳烃污染土壤研究过程中尚存在一些问题,提出了未来植物修复根际效应机理研究中应该关注的重点和方向,旨在为优化多环芳烃污染土壤植物修复技术提供科学依据与理论参考。 相似文献
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多环芳烃胁迫下稻田土壤细菌及分支杆菌种群多样性研究 总被引:1,自引:0,他引:1
多环芳烃(PAHs)污染对土壤微生物群落特别是微生物功能群的影响一直备受关注。本文应用变性梯度凝胶电泳(DGGE)技术,从群落和功能群多样性两个角度,分析了PAHs胁迫条件下稻田土壤细菌遗传多样性及与PAHs降解有密切关系的分支杆菌种群多样性变化。结果表明,PAHs污染对稻田土壤细菌群落多样性指数无显著影响,但造成土壤细菌群落结构的改变,重度PAHs造成一些对污染敏感的细菌种类消失,而使一些与PAHs降解有关的细菌种类丰度增加。而对与多环芳烃降解有密切关系的分支杆菌而言,中度PAHs污染稻田土壤分支杆菌种群多样性指数较重度和轻度PAHs污染土壤的略高,不同PAHs污染程度稻田土壤的优势分支杆菌种类不尽相同,PAHs污染造成稻田土壤1种或几种分支杆菌得到富集。长期PAHs污染造成土壤细菌群落和分支杆菌种群结构的变化,将直接影响土壤生态系统功能的发挥,间接改变土壤质量。 相似文献
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阐述了植物和微生物降解环境中石油污染物及PAHs的重要作用和最新进展。国内外大量实验室研究表明,不同植物和微生物(细菌、真菌和放线菌)联合修复石油污染土壤均得到了较为理想的效果,在某种程度上微生物菌群要优于单一菌株;土壤中植物根系与微生物形成根际效应对污染物的降解起到了促进作用;生物表面活性剂较合成表面活性剂具有更好的生态适宜性和石油污染土壤修复能力;土壤中多组分污染物共同修复虽处于起步阶段,其作用机理也有待进一步研究,但是,发展前景值得期待。目前该领域的研究仍存在一些问题有待解决:植物–微生物菌群降解石油污染物过程中,微生物菌群间协同和竞争机制及试验结果的可重复性尚需证实;实验室研究与大田环境条件的差异,使得目前的研究成果尚需田间试验的验证和支持;根据土壤类型和气候特点,研究极端(高含盐量;氮、磷等营养元素缺乏;低温)条件下的石油高效降解菌株/群,制备有效的便于大田应用的固体菌肥意义重大;同时在确定石油污染物对环境致害的限值的基础上,建立石油污染土壤评价体系也势在必行。 相似文献
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土壤中多环芳烃的微生物降解: 降解途径及其影响影子 总被引:4,自引:0,他引:4
Adverse effects on the environment and high persistence in the microbial degradation and environmental fate of polycyclic aromatic hydrocarbons (PAHs) are motivating interest. Many soil microorganisms can degrade PAHs and use various metabolic pathways to do so. However, both the physio-chemical characteristics of compounds as well as the physical, chemical, and biological properties of soils can drastically influence the degradation capacity of naturally occurring microorganisms for field bioremediation. Modern biological techniques have been widely used to promote the efficiency of microbial PAH-degradation and make the biodegradation metabolic pathways more clear. In this review microbial degradation of PAHs in soil is discussed, with emphasis placed on the main degradation pathways and the environmental factors affecting biodegradation. 相似文献
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Surfactant-Enhanced Soil Washing for Removal of Petroleum Hydrocarbons from Contaminated Soils: A Review 总被引:2,自引:0,他引:2
An increase in energy demand leads to further exploration, transportation, and utilization of petroleum, which creates severe soil contamination because of recurrent accidents and oil spills. Remediation of these contaminated soils is challenging. Among many treatment methods practiced for remediation of petroleum-contaminated soils, surfactant-enhanced soil washing has been widely practiced as a preferred treatment option, as it is a fast and environmentally accepted method. In this paper, we review research undertaken on various anionic, nonionic, cationic, biological, and mixed surfactants for the remediation of petroleum hydrocarbon-contaminated soils. Upcoming surfactants like gemini and switchable surfactants are summarized. We assess the challenges and opportunities of in-situ and ex-situ soil washing, the mechanisms of surfactant-enhanced soil washing, and the criteria to follow for surfactant selection. Furthermore, we briefly discuss the operational and environmental factors affecting soil washing efficiency and soil and surfactant properties affecting surfactant adsorption. We also describe the advantages of coupling soil washing with effluent treatment and surfactant reuse challenges and opportunities. Moreover, challenges and possible new directions for future research on surfactant-enhanced soil washing are proposed. 相似文献
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Purpose
Enhancing desorption of hydrophobic organic contaminants from soils is a promising approach for the effective remediation of soils contaminated with organic compounds. The desorption efficiency of chemical reagent, such as surfactant, should be evaluated. In this study, the effect of mixed anionic–nonionic surfactants sodium dodecylbenzene sulfonate (SDBS)–Tween 80 on the distribution of polycyclic aromatic hydrocarbons in soil–water system was evaluated.Materials and methods
Batch desorption experiments were employed to evaluate the distribution of polycyclic aromatic hydrocarbons (PAHs) and surfactants in soil–water system. PAHs and SDBS were determined by high-performance liquid chromatography, Tween 80 by spectrophotometry, and total organic carbon with a carbon analyzer.Results and discussion
Sorption of PAHs to soil was increased at low surfactant concentration due to the effective partition phase on soil formed by sorbed surfactants. The mixture of anionic and nonionic surfactants decreased the sorption of surfactants to soil, increasing the effective surfactant concentration in solution and thus decreasing the sorption of PAHs on soil. Anionic–nonionic mixed surfactant showed better performance on desorption of PAHs from soil than single surfactant. The greatest desorption efficiency was achieved with low proportions of SDBS (SDBS/Tween80?=?1:9).Conclusions
SDBS–Tween 80 mixed surfactant showed the highest desorption rate with low proportion of SDBS, which indicated that the addition of relative low amount of anionic surfactant could significantly promote the desorption efficiency of PAHs by nonionic surfactants. Results obtained from this study did provide useful information in surfactant-enhanced remediation of soil and subsurface contaminated by hydrophobic organic compounds. 相似文献16.
砷污染土壤的生物修复研究进展 总被引:8,自引:0,他引:8
土壤As污染已是全球性问题,我国也不例外,对As污染土壤的生物修复已是研究热点,但相关机理仍不完全清楚.本文综述了国内外微生物、蚯蚓、植物在As污染土壤中吸收转化As及其解As毒机理,以及微生物-植物复合系统修复As污染土壤方面实验室内研究情况.目前广泛认为植物修复土壤重金属/非金属污染较有应用前景,可限于甚至是使用超富集植物单一作用下仍有较多缺陷,如通过微生物技术及蚯蚓调节根际微生态,以利于植物在污染土壤中存活或/和吸收更多的As,将极具应用前景. 相似文献
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厌氧微生物降解是环境中多环芳烃(polycyclic aromatic hydrocarbons,PAHs)污染削减的重要途径。为系统、全面地了解PAHs厌氧微生物降解的研究现状,以Web of Science核心数据库为数据源,对该领域已发表文献进行文献计量分析,并以厌氧环境中不同还原条件对应的电子受体还原体系为切入点,分别论述反硝化体系、金属离子还原体系、硫酸盐还原体系和产甲烷体系中的PAHs厌氧微生物降解的研究进展,在此基础上重点对土壤中PAHs厌氧微生物降解研究的现存理论空白和未来发展趋势进行探讨。分析结果表明,PAHs厌氧微生物降解领域的研究整体较少,其中,绝大多数仅针对低环PAHs;不同还原条件中对产甲烷和金属离子还原体系的关注也较少;已有研究多侧重纯培养物或水体、沉积物等环境介质,较少基于土壤展开,且新兴技术在该领域尚未得到广泛应用。因此,目前针对土壤中PAHs厌氧微生物降解的认识尚存在诸多理论空白。土壤是环境中PAHs汇集和积累的重要场所,未来应当尝试将单体稳定同位素分析、稳定同位素核酸探针、组学等多种新兴技术与传统研究方法相结合,从多种的角度深入探究土壤PAHs厌氧微生物降解的机制,并将已有的理论和经验在土壤中进行验证,以填补现存理论空白,推进厌氧土壤中PAHs污染微生物修复工作的开展。 相似文献
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Bert van Bavel 《Journal of Soils and Sediments》2006,6(4):208-214
Background, Aim and Scope
Polycyclic aromatic hydrocarbons (PAHs) are formed as a result of incomplete combustion and are among the most frequently
occurring contaminants in soils and sediments. PAHs are of great environmental concern due to their ubiquitous nature and
toxicological properties. Consequently, extensive research has been conducted into the development of methods to remediate
soils contaminated with PAHs. Fenton's reagent or ozone is the most commonly studied chemical oxidation methods. However,
the majority of remediation studies use soils that have been artificially contaminated with either one or a limited number
of PAH compounds in the laboratory. Hence, it is essential to extend such studies to soils contaminated with multiple PAHs
under field conditions.
Objectives The objective of this study is to investigate the capacity of Fenton's reagent and ozone to degrade PAHs in soils. The soils
have been collected from a number of different industrial sites and, therefore, will have been exposed to different PAH compounds
in varying concentrations over a range of time periods. The capacity of Fenton's reagent and ozone to degrade PAHs in industrially
contaminated soils is compared to results obtained in studies using soils artificially contaminated with PAHs in the laboratory.
Materials and Methods:
Nine soil samples, contaminated with PAHs, were collected from five different industrial sites in Sweden. For the Fenton's
reagent procedure, the pH of the soil slurry samples was adjusted to pH 3 and they were kept at a constant temperature of
70oC whilst H2O2 was added. For the ozone procedure, soil samples were mixed with 50% water and 50% ethanol and kept at a
constant temperature of 45 oC. Ozone was then continually introduced to each soil sample over a period of four hours. Following
the Fenton's reagent and ozone oxidation procedures, the samples were filtered to isolate the solid phase, which was then
extracted using pressurized liquid extraction (PLE). The sample extracts were cleaned up using open columns and then analysed
by gas chromatography-mass spectrometry (GC-MS).
Results:
The relative abundance of the detected PAHs varied between soils, associated with different industries. For example, low molecular
weight (LMW) PAHs were more abundant in soil samples collected from wood impregnation sites and high overall PAH degradation
efficiencies were observed in soils originating from these sites. In the contaminated soils studied, PAHs were more effectively
degraded using Fenton's reagent (PAH degradation efficiency of 40-86%) as opposed to ozone (PAH degradation efficiency of
10-70%). LMW PAHs were more efficiently degraded, using ozone as the oxidizing agent, whereas the use of Fenton's reagent
resulted in a more even degradation pattern for PAHs with two through six fused aromatic rings.
Discussion:
The degradation efficiency for both methods was largely dependent on the initial PAH concentration in the soil sample, with
higher degradation observed in highly polluted soils. LMW PAHs are more susceptible to degradation than high molecular weight
(HMW) PAHs. As a result of this the relative abundance of large (often carcinogenic) PAHs increased after chemical oxidation
treatment, particularly after ozone treatment. Repeated Fenton's reagent treatment did not result in any further degradation
of soil PAHs, indicating that residual soil PAHs are strongly sorbed. The effectiveness of the two oxidation treatment approaches
differed between industrial sites, thus highlighting the importance of further research into the influence of soil properties
on the sorption capacity of PAHs.
Conclusions:
This study demonstrates that the degree to which chemical oxidation techniques can degrade soil bound PAHs chemical degradation
is highly dependent on both the concentration of PAHs in the soils and the compounds present, i.e. the various PAH profiles.
Therefore, similarities in the PAH degradation efficiencies in the nine soil samples studied were observed with the two chemical
oxidation methods used. However, the degradation performance of Fenton's reagent and ozone differed between the two methods.
Overall, Fenton's reagent achieved the highest total PAH degradation due to stronger oxidation conditions. LMW PAHs showed
higher susceptibility to oxidation, whereas high molecular weight (HMW) PAHs appear to be strongly sorbed to the soils and
therefore less chemically available for oxidation. This study highlights the importance of including soils collected from
a range of contaminated sites in remediation studies. Such soil samples will contain PAH contaminants of varying concentrations,
chemical and physical properties, and have been aged under field conditions. In addition to the chemical and physical properties
of the soils, these factors will all influence the chemical availability of PAHs to oxidation.
Recommendations and Perspectives:
We recommend including aged contaminated soils in chemical degradation studies. In future chemical remediation work, we intend
to investigate the potential influence of the chemical and physical properties of PAHs and soil parameters potential influence
on the chemical oxidation efficiency in aged contaminated soils.
Due to the vast number of contaminated sites there is a great need of efficient remediation methods throughout the world.
This study shows the difficulties which may be experienced when applying remediation methods to a variation of contaminated
sites. 相似文献
19.
有机质对多环芳烃环境行为影响的研究进展 总被引:21,自引:3,他引:21
多环芳烃(PAHs)的归宿和毒性受其环境行为的影响,主要取决于环境中各个因素的交互作用,而有机质是相当重要的因素,有机质对环境中PAHs的物理化学行为、生物过程均有一定的影响。本文着重介绍了有机质对水体、土壤和沉积物中PAHs的吸附、溶解和迁移以及生物可利用性和毒性等方面的影响,总结了离子强度、pH、表面活性剂、时间等影响有机质与PAHs作用的因素,同时简要介绍了土壤和沉积物中结合残留态PAHs的研究情况,指出结合残留态PAHs现有的研究方法有热解法和同位素标记法,最后提出系统地研究内源有机质(尤其碳黑和腐殖酸)的组成、性质与土壤PAHs的锁定与降解的关系和利用外源有机物强化修复污染的环境是今后研究的重点。 相似文献
20.
Enhanced bioremediation of PAH-contaminated soil by immobilized bacteria with plant residue and biochar as carriers 总被引:2,自引:0,他引:2