重金属污染土壤中生物间相互作用及其协同修复应用

土壤是人类赖以生存的物质基础。我国土壤重金属污染状况不容乐观,给人类健康构成严重威胁。生物修复重金属污染土壤被广泛认为是可持续的修复技术,但当前仍存在修复效率不高的科学瓶颈问题。土壤中生活着丰富的微生物、植物和动物,且这些生物之间存在着复杂的相互作用,并且通过物质循环和能量传递形成了错综复杂的食物网联系。土壤生物间的相互作用能深刻影响土壤中污染物的迁移转化和生物修复的效率,多元生物协同的修复技术集合了单一生物修复方法的优势,具有强化生物修复效果的巨大潜力。文中综述了土壤中微生物-植物-动物之间的相互作用,及其对土壤重金属迁移转化和生物修复效果的影响,并对定向调控土壤食物网结构、提高重金属污染土壤的生物修复效果、建立基于食物网的多元生物协同修复技术进行了展望。     

A comprehensive overview of elements in bioremediation

Sustainable development requires the development and promotion of environmental management and a constant search for green technologies to treat a wide range of aquatic and terrestrial habitats contaminated by increasing anthropogenic activities. Bioremediation is an increasingly popular alternative to conventional methods for treating waste compounds and media with the possibility to degrade contaminants using natural microbial activity mediated by different consortia of microbial strains. Many studies about bioremediation have been reported and the scientific literature has revealed the progressive emergence of various bioremediation techniques. In this review, we discuss the various in situ and ex situ bioremediation techniques and elaborate on the anaerobic digestion technology, phytoremediation, hyperaccumulation, composting and biosorption for their effectiveness in the biotreatment, stabilization and eventually overall remediation of contaminated strata and environments. The review ends with a note on the recent advances genetic engineering and nanotechnology have had in improving bioremediation. Case studies have also been extensively revisited to support the discussions on biosorption of heavy metals, gene probes used in molecular diagnostics, bioremediation studies of contaminants in vadose soils, bioremediation of oil contaminated soils, bioremediation of contaminants from mining sites, air sparging, slurry phase bioremediation, phytoremediation studies for pollutants and heavy metal hyperaccumulators, and vermicomposting.     

The effect of the bioremediation of soil contaminated with petroleum derivatives on the occurrence of epigeic and edaphic fauna

This field study investigated the colonization process of soil contaminated with different petroleum products (petrol, diesel fuel, spent engine oil; dose: 6000 mg of fuel·kg^?1 dry mass [d.m.] of soil) by epigeic and edaphic invertebrates during the progress of natural bioremediation and bioremediation enhanced using selected microorganisms (ZB-01 biopreparation). Epigeic fauna was captured using pitfall traps. Occurrence of edaphic fauna in soil samples as well as total petroleum hydrocarbon contents (TPH) were also investigated. Results showed that inoculation with ZB-01 biocenosis allowed the degradation of petroleum derivatives in the soil contaminated with diesel fuel and engine oil, with 82.3% and 75.4% efficiency, respectively. Applying bioremediation to all contaminated soils accelerated the process of recolonization by edaphic invertebrates. However, the 28-month period was too short to observe full population recovery in soils contaminated with diesel fuel and engine oil. Microbe-enhanced bioremediation accelerated recolonization by epigeic invertebrates on soil contaminated with diesel fuel, whereas it exerted inhibitory effect on recolonization of soil contaminated with engine oil (especially by Collembola). The observed discrepancies in the rates of recolonization for soils contaminated with petrol and diesel fuel that were still noted at the stage of no longer different TPH levels justify the idea to include the survey of edaphic faunal density as one of the parameters in the ecological risk assessment of various bioremediation techniques.     

Enhanced crude oil biodegradation in soil via biostimulation

Research on feasible methods for the enhancement of bioremediation in soil contaminated by crude oil is vital in oil-exporting countries such as Kuwait, where crude oil is a major pollutant and the environment is hostile to biodegradation. This study investigated the possibility of enhancing crude oil bioremediation by supplementing soil with cost-effective organic materials derived from two widespread locally grown trees, Conocarpus and Tamarix. Amendments in soils increased the counts of soil microbiota by up to 98% and enhanced their activity by up to 95.5%. The increase in the biodegradation of crude oil (75%) and high levels of alkB expression substantiated the efficiency of the proposed amendment technology for the bioremediation of hydrocarbon-contaminated sites. The identification of crude-oil-degrading bacteria revealed the dominance of the genus Microbacterium (39.6%), Sphingopyxis soli (19.3%), and Bordetella petrii (19.6%) in unamended, Conocarpus-amended, and Tamarix-amended contaminated soils, respectively. Although soil amendments favored the growth of Gram-negative bacteria and reduced bacterial diversity, the structures of bacterial communities were not significantly altered.     

我国污染土壤生物修复技术的发展及现状

本文简要回顾了近30年来我国污染土壤生物修复技术的发展过程,主要包括生物修复技术在我国的发展阶段、生物修复的4大类型及其所适用对象与范围、生物修复用菌株的筛选与特性研究、活性菌株(菌剂)在典型污染土壤中的应用及其效果等,并针对土壤污染和生物修复技术的发展现状,简要讨论了未来生物修复技术的发展。     

Importance of soil-water relations in assessing the endpoint of bioremediated soils

This study was conducted to investigate water movement in hydrocarbon contaminated soils. Three soils were studied, a hydrocarbon contaminated soil, the same soil after 3 years of bioremediation, and a control soil from the same site. There was a critical soil water content around 18% (bioremediated soil) and 20% (contaminated soil), above which the sorptivity of the contaminated soil was near that of the control soil. For soils with water contents below this value, there was a strong divergence in sorptivity between contaminated and control or bioremediated soils. Results suggest that water availability in contaminated soils will be highly dependent on soil water properties as water potential approaches the permanent wilting point (-1.5 MPa matrix potential).Infiltration of water into air dry (2% m.c. w/w) hydrocarbon contaminated soils was up to three orders of magnitude slower than for the control soil. For air dried soils, the infiltration rate of the contaminated and bioremediated soils was constant with time. This was in contrast to the control soil where infiltration rate was a function of the reciprocal of the square root of time.     

白车轴草(Trifolium repens)植株抗病性和生长与植物病史的关系

从白车轴草(Trifolium repens)自然种群中采集无白车轴草单孢锈菌病史的无性系(clones)17个,有白车轴草单孢锈菌病史的无性系14个,分别作为抗病型和感受型植物实验材料;采集白车轴草单孢锈菌(Uromyces trifolii-repentis)菌系(strains)10个,作为病菌实验材料.分别设置并进行了两个温室实验、一个田间盆栽实验和一个原生长地移栽实验,实验处理上分对照、单菌系接种和10个菌系接种等3种.实验结果表明,无论是用单菌系接种还是10个菌系接种,植株发病的概率和程度均与其抗病性有关,抗病型植株(无病史)发病的概率和程度显著低于感受型(有病史)植株.在相同处理的实验中(无论是田间实验还是温室实验),无病史植株和有病史植株的生长无显著差异;不同处理田间实验植株的生长有显著差异,病情愈重,生长愈差.无病史植株的抗病性明显强于有病史植株.但是,原生长地的移栽实验结果表明,在无病原菌存在的情况下,有病史植株的(叶)生长显著好于无病史植株.可以认为,研究生物个体对环境因子反应性差异的实验应当在自然条件下和自然梯度范围内进行.     

AM真菌对重金属污染土壤生物修复的应用与机理

土壤重金属污染威胁人类健康和整个生态系统,而高效、低耗、安全的生物修复技术显示出了极大的应用潜力,特别是利用植物-微生物共生体增强生物修复效应的应用.丛枝菌根(Arbuscular Mycorrhizae,AM)真菌是一类广泛分布于土壤生态系统中的有益微生物,能与90％以上的陆生高等植物形成共生体.研究发现,AM真菌能够增强宿主植物对土壤中重金属胁迫的耐受性.当前,利用AM真菌开展重金属污染土壤的生物修复已经引起环境学家和生态学家的广泛关注.基于此,围绕AM真菌在重金属污染土壤生物修复作用中的最新研究进展,从物理性防御体系的形成、对植物生理代谢的调控、生化拮抗物质的产生、基因表达的调控等角度探究AM真菌在重金属污染土壤生物修复中的作用机理,以期为利用AM真菌开展重金属污染的生物修复提供理论依据,并对本领域未来的发展和应用前景进行了展望.     

Bioremediation of hydrocarbon-contaminated polar soils

Bioremediation is increasingly viewed as an appropriate remediation technology for hydrocarbon-contaminated polar soils. As for all soils, the successful application of bioremediation depends on appropriate biodegradative microbes and environmental conditions in situ. Laboratory studies have confirmed that hydrocarbon-degrading bacteria typically assigned to the genera Rhodococcus, Sphingomonas or Pseudomonas are present in contaminated polar soils. However, as indicated by the persistence of spilled hydrocarbons, environmental conditions in situ are suboptimal for biodegradation in polar soils. Therefore, it is likely that ex situ bioremediation will be the method of choice for ameliorating and controlling the factors limiting microbial activity, i.e. low and fluctuating soil temperatures, low levels of nutrients, and possible alkalinity and low moisture. Care must be taken when adding nutrients to the coarse-textured, low-moisture soils prevalent in continental Antarctica and the high Arctic because excess levels can inhibit hydrocarbon biodegradation by decreasing soil water potentials. Bioremediation experiments conducted on site in the Arctic indicate that land farming and biopiles may be useful approaches for bioremediation of polar soils.     

Comparative Mesocosm Study of Biostimulation Efficiency in Two Different Oil-Amended Sub-Antarctic Soils

Biological treatment has become increasingly popular as a remediation method for soils and groundwater contaminated with petroleum hydrocarbon, chlorinated solvents, and pesticides. Bioremediation has been considered for application in cold regions such as Arctic and sub-Arctic climates and Antarctica. Studies to date suggest that indigenous microbes suitable for bioremediation exist in soils in these regions. This paper reports on two case studies at the sub-Antarctic Kerguelen Island in which indigenous bacteria were found that were capable of mineralizing petroleum hydrocarbons in soil contaminated with crude oil and diesel fuel. All results demonstrate a serious influence of the soil properties on the biostimulation efficiency. Both temperature elevation and fertilizer addition have a more significant impact on the microbial assemblages in the mineral soil than in the organic one. Analysis of the hydrocarbons remaining at the end of the experiments confirmed the bacterial observations. Optimum temperature seems to be around 10 degrees C in organic soil, whereas it was higher in mineral soil. The benefit of adding nutrients was much stronger in mineral than in the organic soil. Overall, this study suggests that biostimulation treatments were driven by soil properties and that ex situ bioremediation for treatment of cold contaminated soils will allow greater control over soil temperature, a limiting factor in cold climates.     

土壤污染的生物修复技术研究进展

土壤污染是当今面临的一个重要环境问题。常规的土壤污染治理技术,如物理及化学治理技术,由于其技术要求高或经济成本昂贵,对土壤结构的扰动破坏严重,因而对其大规模的推广应用存在较大问题。而生物修复技术已被证明是一项非常有应用前景的新技术,成为土壤污染治理研究领域的一个热点,本文综述了近年来有机物及重金属土壤污染的生物修复机理和研究进展,并对其治理技术的最新研究动态、存在问题及发展趋势做了初步的讨论。     

Effects of humic substances and soya lecithin on the aerobic bioremediation of a soil historically contaminated by polycyclic aromatic hydrocarbons (PAHs)

The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) strongly reduces their bioavailability in aged contaminated soils, thus limiting their bioremediation. The biodegradation of PAHs in soils can be enhanced by employing surface-active agents. However, chemical surfactants are often recalcitrant and exert toxic effects in the amended soils. The effects of two biogenic materials as pollutant-mobilizing agents on the aerobic bioremediation of an aged-contaminated soil were investigated here. A soil historically contaminated by about 13 g kg(-1) of a large variety of PAHs, was amended with soya lecithin (SL) or humic substances (HS) at 1.5% w/w and incubated in aerobic solid-phase and slurry-phase reactors for 150 days. A slow and only partial biodegradation of low-molecular weight PAHs, along with a moderate depletion of the initial soil ecotoxicity, was observed in the control reactors. The overall removal of PAHs in the presence of SL or HS was faster and more extensive and accompanied by a larger soil detoxification, especially under slurry-phase conditions. The SL and HS could be metabolized by soil aerobic microorganisms and enhanced the occurrence of both soil PAHs and indigenous aerobic PAH-degrading bacteria in the reactor water phase. These results indicate that SL and HS are biodegradable and efficiently enhance PAH bioavailability in soil. These natural surfactants significantly intensified the aerobic bioremediation of a historically PAH-contaminated soil under treatment conditions similar to those commonly employed in large-scale soil bioremediation.     

Rhizosphere Microbial Characterization in Petroleum-Contaminated Soil

Contamination of soil with petroleum compounds is of concern worldwide. Although there are a variety of physical and chemical technologies available to remediate petroleum waste sites, biological methods are often used due to lower cost and public acceptance. Growth and enhanced activity of microbial communities in contaminated soil is a key factor for the success of bioremediation. Establishing vegetation in petroleum-contaminated soil may enhance microbial activity and remediation success even further by providing root exudates to the rhizosphere microorganisms. In this study, microorganisms were characterized in petroleum-contaminated soils and sediments quantitatively and qualitatively based on enumeration and metabolic diversity assessments. Contaminated soils and sediments were obtained from a phytoremediation field demonstration project in California. Microbial numbers in the unvegetated soil, based on plate counts and most probable number of hydrocarbon degraders, were significantly lower than the vegetated soils. Metabolic microbial characterization using BIOLOG was also conducted and based on principle component analysis (PCA), there was a distinct difference between the metabolic diversity of microbial communities in vegetated and unvegetated soils. Results from this research indicate that the presence and type of plants, and level of contamination may greatly influence microbial communities in polluted soils.     

石油污染土壤的生物修复技术

1　前　言在石油生产、贮运、炼制加工及使用过程中 ,由于事故 ,不正常操作及检修等原因 ,都会有石油烃类的溢出和排放。例如 ,油田开发过程中的井喷事故 ;输油管线和贮油罐的泄漏事故 ;油槽车和油轮的泄漏事故 ;油井清蜡和油田地面设备检修 ;炼油和石油化工生产装置检修等。石油烃类大量溢出 ,应当尽可能予以回收 ,但有的情况下回收很困难 ,即使尽力回收 ,仍会残留一部分 ,对环境 (土壤、地面和地下水 )造成污染。其进入土壤后 ,会破坏土壤结构 ,分散土粒 ,使土壤的透水性降低。其富含的反应基能与无机氮、磷结合并限制硝化作用和脱磷酸作…     

Enhanced biodegradation of transformer oil in soils with cyclodextrin – from the laboratory to the field

The use cyclodextrins for the intensification of bioremediation by improving the mobility and bioavailability of contaminants has recently been studied. In this work, the role of randomly methylated -cyclodextrin in the bioremediation of soils contaminated with transformer oil was studied both in bench scale bioreactors and through field experiments. The aims of this research were to (a) establish the scientific background of a cyclodextrin-based soil bioremediation technology, (b) demonstrate its feasibility and effectiveness in the field, and (c) develop an integrated methodology, consisting of a combination of physical, chemical, biological and ecotoxicological analytical methods, for efficiently monitoring the technology performances. The stepwise increasing scale of the experiments and the application of the integrated analytical methodology supported the development of a scientifically established new technology and the identification of the advantages and the limitations of its application in the field. At each phase of the study, randomly methylated -cyclodextrin was found to significantly enhance the bioremediation and detoxification of the transformer oil-contaminated soils employed by increasing the bioavailability of the pollutants and the activity of indigenous microorganisms.     

石油污染土壤堆制微生物降解研究

采用异位生物修复技术堆式堆制处理方法 ,对辽河油田原油污染土壤进行了生物修复处理研究 .处理工程设 4个处理料堆单元 ,每个处理单元长 118.5cm ,宽 6 5 .5cm ,高 12 .5cm .研究结果表明 ,当进行处理的石油污染土壤中石油烃总量为 5 .2 2 g·10 0 g-1土时 ,利用黄孢原毛平革菌 (Phanerochaetechrysospori um) ,经过 5 5d的运行 ,石油烃总量去除率达 5 4.2 % .堆制处理中影响污染土壤石油烃总量生物降解的主要变化因子为污染土壤的O2 和CO2 含量、降解石油烃微生物的数量、污染土壤pH的变化 .通过监测这些数据的变化 ,可直接反映该工程的处理石油污染土壤的效果 .本处理工程采用定期通风措施 ,操作简单、运行费用低廉 ,为石油污染土壤生物修复实用化提供了一种简单易行的污染土壤清洁技术 .     

PAH Phytoremediation: Rhizodegradation or Rhizoattenuation?

Dealing with soil contaminated with persistent organic pollutants (POP) is an increasing concern amplified by both regulatory constraints and the dramatic impact of human activities on the soil resource. The most used management options are treatments which totally eradicate the toxic compounds targeted. When possible, environmental-friendly processes should be used, and recent years have seen the emergence of green technologies using biological energies involving microorganisms (bioremediation) and plants (phytoremediation). Research has focused on phytoremediation and many have presented this technology as the process ideally combining efficiency, low cost and environmental acceptance. However, the applicability of phytoremediation on soils contaminated by bio-recalcitrant organic compounds, such as polycyclic aromatic hydrocarbons (PAH), has not yet proved as successful as expected. We propose here a review and discussion of the overall question of PAH status in soil and their potential for treatment. The limits and applicability of bioremediation technologies are discussed, and the specific beneficial effect of plants is objectively evaluated with a special interest to processes which lead to rhizoattenuation. Given the PAH high affinity to soil organic matter, availability is the main limitation to phytoremediation. In this context, bioavailability quantification remains an issue as well as the characterization of the recalcitrant fraction.     

土壤中高环多环芳烃微生物降解的研究进展

微生物修复是去除土壤中多环芳烃(PAHs)的主要措施。本文以微生物修复PAHs污染土壤的理论基础及其难点为主线,全面综述了土壤中高环PAHs的微生物降解机理。近年来,富集分离得到的以高环PAHs为唯一碳源和能源的优势降解菌逐渐增多,其中,主要是代谢降解四环PAHs的单株降解菌,一些降解菌还能以共代谢方式利用五环PAHs。高环PAHs污染土壤修复的一个难点是其低生物可利用性,微生物通过释放生物表面活性剂、形成生物膜以及分泌胞外多糖提高高环PAHs的生物可利用性,从而加速其降解。真菌和细菌联合作用能增强污染土壤实地修复的效果。因此,通过微生物修复技术来去除土壤中PAHs具有环境友好性、经济适用性以及可持续应用性。