有机污染土壤电动-微生物修复过程中的影响因素及优化措施

生物修复技术因其费用低、对环境不产生二次污染而被视为是一项具有广阔发展前景的技术。然而,一些强疏水性的有机污染物,生物可利用性很差,严重阻碍了其生物降解效率。电动与微生物联合修复技术(电动-微生物修复),在顽固性有机污染物的去除方面表现出巨大潜力。电场的施加可向土壤中分散外源物质、营养物质和微生物;或通过增强土壤中有机污染物与降解菌的传质过程,提高难降解有机物的生物可利用性;还可诱使土壤中的污染物产生电化学反应,增强污染物的去除效果。文章对有机污染土壤的电动-微生物修复过程的影响因素及优化措施进行了综述。文章认为,影响电动-微生物修复效率的因素主要有电场强度、污染物的生物可利用性、污染物结构和性质、微生物种群以及环境因素(如土壤pH值、土壤类型、营养物质、含水量等)。因此,在实施修复的过程中应根据污染场址的电化学特性选择合适的电流或电压梯度;另外,可通过施加表面活性剂、助溶剂或螯合剂,构建微生物群落,以及优化土壤环境条件,如调整土壤pH、提供营养物质、电子受体、共代谢基质等方式优化有机污染土壤电动-微生物修复的过程。深入研究有机污染土壤电动-微生物修复过程中的影响因素和优化措施,有望为电动-微生物修复技术在有机污染土壤的场地修复及过程调控中的应用提供一定的理论依据。     

多溴联苯醚微生物降解过程与机理的研究进展

多溴联苯醚(PBDEs)属溴代阻燃剂,曾因其优良的阻燃性能而广泛应用于电子电器、石油化工和建材纺织等工业产品中.然而,随着大量生产和使用,PBDEs已成为大气、水体、土壤和生物体等多环境介质中普遍检出且极具生态风险的有机污染物.因此,开展微生物降解研究对于典型环境中PBDEs污染风险消除和污染修复,具有重要的科学意义.本文从PBDEs环境归趋行为及其暴露风险出发,综述了PBDEs微生物厌氧降解和好氧降解的最新研究动态,比较分析了两种降解过程的降解特性与影响因素,并针对微生物,尤其是好氧微生物降解机理,阐述了bph A或etb A功能基因及其编码酶对PBDEs好氧降解过程的调控作用,同时就PBDEs微生物高效降解菌种选育、降解机理等方面的研究趋势进行了展望.     

生物质炭强化土壤中有机污染物的微生物降解及电子传递机制

生物质炭(BC)具有吸附土壤中有机污染物的能力,同时自身具有一定的氧化还原性,对土壤中有机污染物的降解具有重要影响。通过改善土壤理化性质,BC能够增强土壤微生物的活性,在与微生物共同作用下促进土壤中有机污染物的降解。这种促进作用与生物质炭提供的电子转移能力有关。因此,探究有机污染物、生物质炭和微生物之间的电子传递机制,对了解土壤中有机污染物的降解规律十分必要。本研究主要综述了BC增强微生物降解有机污染物及其介导电子传递的机制,并归纳了增强生物质炭介导电子传递能力的方法。另外,本研究还提出了微生物穿梭电子的作用范围与贡献大小、BC的电子交换能力测定标准方法、BC在土壤环境中长期效应等方面的研究和应用存在的不足。本研究对BC在土壤污染治理中的应用提供了重要的参考价值,并为使用BC增强土壤微生物降解有机污染物提供了新思路。     

土壤中总石油烃污染（TPH）的微生物降解与修复研究进展

微生物降解和修复是处理土壤中总石油烃(TPH)污染最简单、有效的方法之一.论文阐述了土壤TPH污染的产生、危害以及物理、化学、生物等修复方法的各自特点,其中重点介绍了微生物修复方法,论述了土壤中TPH在微生物表面的吸附、转运,在微生物体内的降解以及相关降解酶及基因;详细介绍了电子受体、温度、pH、营养元素等外界因素对微生物修复TPH污染的影响,在此基础上对土壤TPH污染的微生物修复现状和发展趋势进行了讨论.     

藻类对壬基酚微生物降解的影响

壬基酚(NP)为在水环境中广泛存在的一种典型环境内分泌干扰物质。为了探讨NP在自然水体中的归趋,研究了水体中藻类对微生物降解NP的影响。结果表明,本研究筛选的耗氧混合菌可以有效降解NP,在暗环境下半衰期为1.16d,光照不利于NP的微生物降解,半衰期增加到5.19d;藻类和藻胞外分泌物可以提高光照条件下NP的微生物降解,这是藻类和菌加和作用的结果;而破碎的藻对降解作用改善不大。藻类和微生物相互作用对于有机污染物降解的影响还鲜见报道,本研究为全面理解NP在水环境中的归驱提供了重要的数据。     

污染土壤中菲的修复技术研究进展

菲是多环芳烃中的代表性物质,具有"三致"效应,而且菲的蒸汽压小,辛醇-水分配系数高,生物可利用性低,是一种持久性有机污染物。随着化石燃料的大量使用,受菲污染的土壤越来越多,研究菲的修复技术对污染土壤的再利用具有重要意义。结合目前国内外研究进展,综述了污染土壤中菲的修复方法,包括物理修复、化学修复和生物修复。针对各种修复方法,阐述了其原理、修复条件、实例应用和优缺点,重点论述了植物修复和微生物修复方法的降解机理和应用,分析了微生物性质,包括氧、营养物、温度、土壤理化性质、共存污染物等环境因素对生物降解的影响。由于溶解性的菲有较好的迁移转化能力,因此表面活性剂的助溶作用适用于各种修复方法,选择合适的表面活性剂可以提高修复效果。在各种修复技术中,物理修复是通过物理技术实现菲的解吸与富集,无污染,但是去除率低;化学修复是使用氧化剂将菲氧化分解成无毒易降解的小分子物质或通过添加化学淋洗剂增加菲的溶解性,提高迁移转化能力,用时短,但是引入其他试剂,容易造成二次污染;植物修复是通过植物的提取、降解和固定等过程实现菲的修复,尤其是植物的根际环境为微生物的生长提供有利的条件;微生物修复以菲可作为微生物生长的碳源为基础,在分解酶的作用下实现菲的降解,但是生物修复周期长,可利用的生物少,而且可能生成毒性更高的中间代谢产物。因此,寻找合适的修复物种,采用基因技术提高生物的修复能力或多法联用、取长补短可提高修复效率。最后,在共降解理论的基础上,结合重金属和有机污染物共存时,一种物质的存在对另一种物质的降解有促进作用,提出了协同降解的概念,寻求对多种污染物有协同降解或共降解作用的修复方法是今后发展的主要方向。     

一株同时降解3种邻苯二甲酸酯降解菌的筛选鉴定及降解特性

选择邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二丁酯(DnBP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)作为目标污染物,采用富集驯化法从设施菜地土壤中筛选出1株可同时降解DMP、DnBP和DEHP的细菌MB1.经形态、生理生化特征及16S rDNA序列分析,初步鉴定为微杆菌属(Microbacterium sp.).通过正交试验研究了该菌株的最优降解条件以及最优条件下该菌株的生长曲线和降解曲线,最后在培养条件下研究了该菌株对人工污染土壤中邻苯二甲酸酯的降解特性.结果表明,菌株MB1的最优降解条件为:pH值为8,温度为25℃,接菌量为5%,每种邻苯二甲酸酯浓度为300 mg·L~(-1).在此最优条件下该菌株呈S型曲线增长,7 d后无机盐培养液中DMP、DnBP和DEHP的降解率分别为99.62%%、99.65%和55.26%.人工污染土壤中空白试验和投加菌株试验结果为:在不添加菌液的处理中,灭菌土壤21 d时DMP、DnBP和DEHP的降解率分别为3.86%、4.19%和2.01%;未灭菌土壤21 d时对DMP、DnBP和DEHP的降解率分别为4.82%、5.99%和3.44%.在添加菌液的处理中,21 d时土壤灭菌处理中DMP、DnBP和DEHP的降解率分别达94.45%、95.65%和39.21%;而土壤未灭菌处理中DMP、DnBP和DEHP的降解率分别达94.93%、95.99%和41.16%.该结果表明:土壤中土著微生物仅能降解微量PAEs,菌株MB1对土壤中DMP、DnBP和DEHP等3种PAEs污染物具有较为高效的降解能力,未灭菌土壤中邻苯二甲酸酯的降解效果略高于灭菌土壤.     

杀草丹降解菌Bacillus sp. T2的筛选、鉴定及降解特性

为研发稻田除稗剂杀草丹污染环境的生物修复技术和探究杀草丹微生物降解代谢机制,通过微生物驯化与富集技术,从长期施用杀草丹水稻田土样中分离纯化一株能够以杀草丹为唯一碳源生长的高效降解菌株T2,在36 h内对0.4 mmol/L的杀草丹降解率达到98.3%以上.根据其形态、生理生化特征及16S rRNA基因序列相似性分析,将其初步鉴定为芽孢杆菌属(Bacillus sp.T2).通过GC-MS鉴定产物为对氯苄硫醇、对氯苯甲醛和对氯苯甲酸;依据产物鉴定结果推测菌株T2通过硫酯键水解的方式起始杀草丹的降解,首先将其转化为对氯苄硫醇,随后进一步被氧化为对氯苯甲醛和对氯苯甲酸,该降解途径可能是一种新的杀草丹微生物降解代谢途径.因此菌株Bacillus sp.T2对杀草丹具有非常高的降解效率,在污染环境的微生物修复方面具有很好的应用前景;本研究结果也为揭示土壤中杀草丹微生物降解代谢过程及机制提供了研究材料和理论依据.     

生物强化技术及其在污水处理中应用研究评述

在传统废水生物处理过程中,难降解有机污染物的存在和外界环境的变化会抑制土著微生物的活性,从而影响废水处理效果。生物强化技术是向生物处理系统中引入特定的高效降解功能微生物,通过微生物自身所具备的降解机制对污染物质进行降解,达到有效处理废水的目的。相较于传统生物处理法,生物强化技术能更好地提高难降解污染物处理效果,维持系统的稳定性,减少污泥的产生,缩短系统的启动时间,并可以使系统表现出良好的抗冲击负荷能力。目前生物强化技术研究主要集中在高效菌群对难降解有机污染物的高效降解作用和优势菌种对于极端环境的耐受能力等方面。文章综述了生物强化技术的作用机理,主要有高效菌通过自身携带的降解基因或分泌的降解酶对污染物质的直接降解作用、微生物的共代谢作用和群体感应作用;介绍了生物强化技术中优势菌种的3种获取方式,分别是从自然界中直接进行驯化筛选、构造基因工程菌以及通过水平基因转移获取的方式;论述了生物强化技术的作用形式,包括直接将微生物投加到目标水体中、应用微生物固定化技术和研制生物强化菌剂进行投加的3种方式;另外还总结了近几年来生物强化技术在景观水体、土壤修复、产能和水处理等方面的应用,最后阐述了生物强化技术研究存在问题和新路径。     

接种邻苯二甲酸酯(PAEs)降解菌缓解PAEs对玉米胁迫效应和机制研究

邻苯二甲酸酯(PAEs)是一类典型的环境内分泌干扰物,国内农业土壤普遍受PAEs的污染。土壤中的PAEs可被农作物吸收累积,影响植物的生理生化特性和农产品的质量安全。探索PAEs污染土壤的生物修复技术以及高效降解菌缓解PAEs污染胁迫和降低农作物吸收累积PAEs迫在眉睫。以在土壤中的质量分数和检出频率均较高的邻苯二甲酸二(2-乙基己基)酯(DEHP)为目标化合物,采用DEHP污染土壤(18 mg·kg~(-1)和75 mg·kg~(-1))进行盆栽玉米(Zea mays)试验,研究接种PAEs高效降解菌(嗜吡啶红球菌Rhodococcus pyridinivorans XB)缓解DEHP胁迫对玉米生长、吸收积累DEHP的影响及其抗氧化酶系统的响应。结果显示,经DEHP处理的玉米丙二醛质量摩尔浓度显著增加(P0.05),尤其是高浓度处理的玉米根系丙二醛质量摩尔浓度增加464%;且高浓度处理的玉米根系过氧化氢酶和多酚氧化酶活性显著增加(P0.05),生物量显著下降(P0.05),说明DEHP严重影响玉米的生长。与不接种微生物处理相比,玉米接种菌株XB能显著提高玉米体内超氧化物歧化酶(10%~154%)、过氧化氢酶(11%~34%)及多酚氧化酶(48%~288%)活性,显著降低丙二醛质量摩尔浓度(30%~60%),提高玉米生物量(5%~85%),减少玉米对DEHP的吸收积累(4%~60%)。结果说明菌株XB能缓解土壤DEHP对玉米生长的胁迫,降低玉米吸收积累DEHP,有利于保障农产品质量安全。     

Phthalate esters contamination in soil and plants on agricultural land near an electronic waste recycling site

The accumulation of phthalic acid esters (PAEs) in soil and plants in agricultural land near an electronic waste recycling site in east China has become a great threat to the neighboring environmental quality and human health. Soil and plant samples collected from land under different utilization, including fallow plots, vegetable plots, plots with alfalfa (Medicago sativa L.) as green manure, fallow plots under long-term flooding and fallow plots under alternating wet and dry periods, together with plant samples from relative plots were analyzed for six PAE compounds nominated as prior pollutants by USEPA. In the determined samples, the concentrations of six target PAE pollutants ranged from 0.31–2.39 mg/kg in soil to 1.81–5.77 mg/kg in various plants (dry weight/DW), and their bioconcentration factors (BCFs) ranged from 5.8 to 17.9. Health risk assessments were conducted on target PAEs, known as typical environmental estrogen analogs, based on their accumulation in the edible parts of vegetables. Preliminary risk assessment to human health from soil and daily vegetable intake indicated that DEHP may present a high-exposure risk on all ages of the population in the area by soil ingestion or vegetable consumption. The potential damage that the target PAE compounds may pose to human health should be taken into account in further comprehensive risk assessments in e-waste recycling sites areas. Moreover, alfalfa removed substantial amounts of PAEs from the soil, and its use can be considered a good strategy for in situ remediation of PAEs.     

微生物修复土壤多环芳烃污染的研究进展

多环芳烃是一类具有致癌、致畸、致突变性质的持久性有机污染物,主要来源于煤、石油等燃料的不完全燃烧,易吸附于固体颗粒表面和有机腐殖质,化学结构稳定,能长期存在于自然环境,给人类健康和生态环境带来很大的危害。中国土壤多环芳烃污染严重,因此急需寻求有效的修复方法进行治理。在众多的多环芳烃污染修复方法中,微生物修复因其低成本、高效、污染少等优点成为研究热点。科学家们从自然界中分离出了多种细菌、真菌等具有降解多环芳烃能力的微生物,并对多环芳烃的降解机理进行了探索,结果表明,微生物在代谢活动过程中能够产生酶来实现对土壤中多环芳烃的降解。细菌主要通过产生双加氧酶来催化多环芳烃的加氧反应,而真菌可以通过分泌木质素降解酶系或单加氧酶来氧化多环芳烃。两种途径均是首先通过降低多环芳烃的稳定性,使之容易被进一步降解。目前,微生物修复技术正逐步应用于PAHs污染土壤的实地修复,且已取得一定成效。文章简要介绍了降解多环芳烃的微生物,对多环芳烃的微生物降解机制进行了综述,讨论了影响微生物修复过程的因素,列举了常见的微生物修复相关技术,展望了今后的研究趋势。     

Integration of microbial reductive dehalogenation with persulfate activation and oxidation (Bio-RD-PAO) for complete attenuation of organohalides

•Bio-RD-PAO can effectively and extensively remove organohalides. •Bio-RD alone effectively dehalogenate the highly-halogenated organohalides. •PAO alone is efficient in degrading the lowly-halogenated organohalides. •The impacts of PAO on organohalide-respiring microbial communities remain elusive. •Bio-RD-PAO provides a promising solution for remediation of organohalide pollution. Due to the toxicity of bioaccumulative organohalides to human beings and ecosystems, a variety of biotic and abiotic remediation methods have been developed to remove organohalides from contaminated environments. Bioremediation employing organohalide-respiring bacteria (OHRB)-mediated microbial reductive dehalogenation (Bio-RD) represents a cost-effective and environmentally friendly approach to attenuate highly-halogenated organohalides, specifically organohalides in soil, sediment and other anoxic environments. Nonetheless, many factors severely restrict the implications of OHRB-based bioremediation, including incomplete dehalogenation, low abundance of OHRB and consequent low dechlorination activity. Recently, the development of in situ chemical oxidation (ISCO) based on sulfate radicals (SO₄^·−) via the persulfate activation and oxidation (PAO) process has attracted tremendous research interest for the remediation of lowly-halogenated organohalides due to its following advantages, e.g., complete attenuation, high reactivity and no selectivity to organohalides. Therefore, integration of OHRB-mediated Bio-RD and subsequent PAO (Bio-RD-PAO) may provide a promising solution to the remediation of organohalides. In this review, we first provide an overview of current progress in Bio-RD and PAO and compare their limitations and advantages. We then critically discuss the integration of Bio-RD and PAO (Bio-RD-PAO) for complete attenuation of organohalides and its prospects for future remediation applications. Overall, Bio-RD-PAO opens up opportunities for complete attenuation and consequent effective in situ remediation of persistent organohalide pollution.     

Applications of hollow nanomaterials in environmental remediation and monitoring: A review

Hollow nanomaterials have attracted significant attention because of their high chemical and thermal stability, high specific surface area, high porosity, low density, and good biocompatibility. These state-of-the-art nanomaterials have been shown to efficiently adsorb heavy metals, and volatile hazardous substances, photodegrade persistent organic pollutants, and other compounds, and inactivate bacteria. Such properties have enabled the use of these materials for environmental remediation, such as in water/wastewater treatment, soil remediation, air purification, and substance monitoring, etc. Hollow nanomaterials showed higher photocatalytic activity than those without hollow structure owing to their high active surface area, reduced diffusion resistance, and improved accessibility. And, the Doping method could improve the photocatalytic performance of hollow nanomaterials further under visible light. Moreover, the synthetic mechanisms and methods of these materials are important because their size and morphology help to determine their precise properties. This article reviews the environmental applications and potential risks of these materials, in addition to their syntheses. Finally, an outlook into the development of these materials is provided.     

植物-微生物修复石油烃污染土壤与根际微生态环境变化

石油烃作为一类持久性难降解有机污染物对土壤环境质量产生严重的危害。以天津大港油田原油污染土壤中筛选出的耐低温高效石油烃降解菌为靶细胞,以小麦、紫花苜蓿作为供试植物,利用盆栽试验,对植物-外源菌协同修复体系中的脱氢酶活性和土壤微生物多样性进行研究,分析其变化及其与石油烃降解率的关系。结果表明植物-微生物协同修复对石油烃具有较好的降解能力,其中小麦-固定化外源菌组具有最高的降解率,石油烃含量从最初的30 600 mg獉kg-1下降为24 300 mg獉kg-1,降解率为20.6%,并且其试验后期石油烃的降解率最大,远远高于其他时期,表现出良好的修复潜力。外源菌投加的初始阶段会迅速提高脱氢酶活性,然而这种影响随着降解时间延长而逐渐减弱。初期脱氢酶活性与总石油烃的降解存在较好的相关性,脱氢酶活性可以在一定程度上表征土壤石油烃的降解情况。微生物多样性与总石油烃降解也存在一定的相关性。     

Review on remediation technologies for arsenic-contaminated soil

• Recent progress of As-contaminated soil remediation technologies is presented. • Phytoextraction and chemical immobilization are the most widely used methods. • Novel remediation technologies for As-contaminated soil are still urgently needed. • Methods for evaluating soil remediation efficiency are lacking. • Future research directions for As-contaminated soil remediation are proposed. Arsenic (As) is a top human carcinogen widely distributed in the environment. As-contaminated soil exists worldwide and poses a threat on human health through water/food consumption, inhalation, or skin contact. More than 200 million people are exposed to excessive As concentration through direct or indirect exposure to contaminated soil. Therefore, affordable and efficient technologies that control risks caused by excess As in soil must be developed. The presently available methods can be classified as chemical, physical, and biological. Combined utilization of multiple technologies is also common to improve remediation efficiency. This review presents the research progress on different remediation technologies for As-contaminated soil. For chemical methods, common soil washing or immobilization agents were summarized. Physical technologies were mainly discussed from the field scale. Phytoextraction, the most widely used technology for As-contaminated soil in China, was the main focus for bioremediation. Method development for evaluating soil remediation efficiency was also summarized. Further research directions were proposed based on literature analysis.     

中国土壤与沉积物中邻苯二甲酸酯污染水平及其吸附研究进展

邻苯二甲酸酯（PAEs）是一类重要的环境激素化合物,具有致畸性、致癌性、致突变性及生殖毒性的特点。在环境中普遍存在,对人体及生态环境的威胁极大,已经引起了人们广泛的关注。吸附作用是影响污染物在土壤及沉积物环境中迁移转化的关键因素之一。分析了近年来我国土壤及沉积物中PAEs的污染现状,归纳了影响PAEs吸附过程的主要因素。我国与世界其他各国的土壤及沉积物的PAEs主要污染组分较为一致,但PAEs污染相对严重。土壤有机质及粘土矿物对PAEs的吸附影响成为了学术界的研究热点。有机质中的腐殖质对PAEs的吸附起着决定作用;腐殖质由胡敏酸、富里酸及胡敏素,部分含有碳黑组成,各组成对PAEs的吸附影响大小不一,相应的吸附机理还有待于深入的研究,而且土壤与沉积物中的溶解性有机物（DOM）对PAEs的吸附双重影响认识还不够。在有机质含量低的土壤中,粘土矿物对PAEs的吸附起着主要作用,然而PAEs的吸附与粘土矿物类型及其表面电场的关系、是否能与水分子竞争表面电场等问题还不甚清楚,需要进一步探索。今后将引入并开发先进的分析测试技术,从土壤及沉积物的有机质组成及微观结构研究其对PAEs的吸附机理。     

The evolution of pollution profile and health risk assessment for three groups SVOCs pollutants along with Beijiang River,China

Three important groups of semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), organic chlorinated pesticides (OCPs) and phthalate esters (PAEs), were produced by various human activities and entered the water body. In this study, the pollution profiles of three species including 16 PAHs, 20 OCPs and 15 PAEs in water along the Beijiang River, China were investigated. The concentrations of Σ₁₆PAHs in the dissolved and particulate phases were obtained as 69–1.5 × 10² ng L^?1 and 2.3 × 10³–8.6 × 10⁴ ng g^?1, respectively. The levels of Σ₂₀OCPs were 23–66 ng L^?1 (dissolved phase) and 19–1.7 × 10³ ng g^?1 (particulate phase). Nevertheless, higher levels of PAEs were found both in the dissolved and particulate phases due to abuse use of plastic products. Furthermore, non-cancer and cancer risks caused by these SVOCs through the ingestion absorption and dermal absorption were also assessed. There was no non-cancer risk existed through two kinds of exposure of them at current levels, whereas certain cancer risk existed through dermal absorption of PAHs in the particulate phase in some sampling sites. The results will show scientific insights into the evaluation of the status of combined pollution in river basins, and the determination of strategies for incident control and pollutant remediation.     

A review of combinations of electrokinetic applications

Anthropogenic activities contaminate many lands and underground waters with dangerous materials. Although polluted soils occupy small parts of the land, the risk they pose to plants, animals, humans, and groundwater is too high. Remediation technologies have been used for many years in order to mitigate pollution or remove pollutants from soils. However, there are some deficiencies in the remediation in complex site conditions such as low permeability and complex composition of some clays or heterogeneous subsurface conditions. Electrokinetic is an effective method in which electrodes are embedded in polluted soil, usually vertically but in some cases horizontally, and a low direct current voltage gradient is applied between the electrodes. The electric gradient initiates movement of contaminants by electromigration (charged chemical movement), electro-osmosis (movement of fluid), electrolysis (chemical reactions due to the electric field), and diffusion. However, sites that are contaminated with heavy metals or mixed contaminants (e.g. a combination of organic compounds with heavy metals and/or radionuclides) are difficult to remediate. There is no technology that can achieve the best results, but combining electrokinetic with other remediation methods, such as bioremediation and geosynthetics, promises to be the most effective method so far. This review focuses on the factors that affect electrokinetic remediation and the state-of-the-art methods that can be combined with electrokinetic.     

Remediation of soil heavily polluted with polychlorinated biphenyls using a low-temperature plasma technique

Polychlorinated biphenyls （PCBs） were removed by low-temperature plasma technique （dielectric barrier discharge） from heavily polluted soil and their intermediate products were analyzed. The removal rate ranged from 40.1 to 84.6% by different treatments, and they were also influenced significantly （P 〈 0.01） by soil particle-size, electric power, gas flow rate and reaction time. The optimal reaction conditions of PCB removal from the soil were obtained experimentally when soil particle-size, electrical power, flow rate and reaction time were 5-10mm, 21w, 120mL. rain and 90rain, respectively. However, decreasing electrical power, flow rate and reaction time to 18 w, 60 mL. min- and 60 min respectively were also acceptable in view of the cost of remediation. This technique was characterized by the additional advantage of thorough oxidation of PCBs in the soil, with no formation of intermediate products after reaction. The technique therefore shows some promise for application in the remediation of soils contaminated with persistent organic pollutants in brown field sites in urban areas.