土壤重金属污染修复技术研究进展

近年来随着社会经济的快速发展,土壤受重金属污染问题日益显著,土壤污染不仅对整个土壤圈层造成危害,而且对其它各大圈层也造成一定的影响,如水体污染、空气污染等.其污染源主要分为自然源和人工源2大类,所涉及到的重金属元素主要有Hg、Cd、Pb、Cr、As、Zn、Cu、Ni等元素,如何有效地治理土壤重金属污染对农产品安全和人类健康发展具有重要意义.因此文中从土壤重金属污染来源,国内外土壤修复研究现状,土壤重金属污染修复技术的研究进展几个方面阐述,目前土壤重金属污染修复所采用的技术主要有物理修复、化学修复、生物修复、农业生态修复以及联合修复技术,阐述各修复技术的原理、适用条件、应用实例并分析其优点和不足,其中最为常用的修复手段为生物修复,而联合修复因具备其它单一修复技术所不具备的优越性,可以作为今后在土壤修复领域的重点发展方向,以期为我国受污染土壤的治理借鉴经验.      

多环芳烃污染土壤生物修复技术研究进展

多环芳烃污染土壤的面积伴随着生物质燃料的广泛应用不断增加,污染程度亦随之增强,研究污染土壤高效修复方法已刻不容缓.生物修复相对于物理和化学修复具有费用低、效果好、不产生二次污染等优点.植物-微生物联合修复体系则是其中最为高效、最具市场潜力的修复技术.详细介绍了微生物修复与植物-微生物联合修复技术的机理及应用, 并展望了多环芳烃污染土壤生物修复的发展趋势.     

土壤重金属污染及修复研究现状

阐述土壤中重金属污染来源和存在形式,对比分析物理修复法、化学修复法和生物修复法修复技术的优缺点,提出了当前土壤重金属污染与修复技术研究的重点,为针对复合污染进行的联合修复提供理论依据.     

汞污染修复技术研究进展

汞污染作为全球性的污染问题，已广泛影响到人们的生活。随着工业化进程的加快，汞污染带来的不良影响日趋严重，这使得人们越发关注对汞污染修复方法的研究。为了更好地掌握当前汞污染修复技术的发展现状，介绍了环境介质(大气、水和土壤)中汞的来源及汞对环境造成的危害，从物理修复、化学修复、生物修复、基因工程修复和纳米修复5个方向具体阐述了当前各种汞污染修复技术的原理和适用场景，并对各修复技术的优缺点进行分析，同时对汞污染修复技术发展方向提出了展望。     

铬污染毒性土壤清洁修复研究进展与综合评价

综述了土壤中铬的来源,土壤中铬的赋存形式及其提取方法,国内外铬污染土壤修复技术研究动态,探讨了铬污染土壤修复的发展方向,并对现阶段主要的修复技术,诸如客土法、稀释法、固定化和稳定化、化学还原、土壤淋洗、电动修复、生物修复等进行了详细介绍,进而对各种修复方法的优缺点进行了对比、归纳和评价,针对不同特点、性质的铬污染土壤给出修复方法的建议,为清洁高效修复铬污染土壤提供参考.      

镉污染土壤修复治理技术研究

镉是一种毒性较强的重金属元素,易被动植物吸收富集而产生危害。研究镉污染农田土壤修复技术及安全利用方法对保护生态环境及保障食品安全具有重大意义。目前,镉及其镉化合物被广泛应用,导致越来越多的土壤被镉等重金属污染,环境问题也变得越来越突出。文章就土壤镉污染修复技术及安全利用方法存在效率低、体系不稳定等问题,探究土壤镉生物有效性关键调控因子及其作用机制、充分挖掘特殊镉累积特性的植物资源并探寻改造植物镉耐性的方法以提高镉污染土壤修复效率。     

有色金属矿山重金属污染土壤修复技术研究进展

我国有色金属种类与产量众多,有色金属矿区的土壤普遍存在重金属污染状况。介绍了有色金属矿区重金属污染的来源,重点对矿区重金属污染土壤的不同修复技术进行了阐述,客土法、换土法、玻璃固定化、热脱附技术适合小范围内的土壤修复。土壤淋洗、化学稳定化修复效率较快,但因为要外加药剂,处理不当很容易造成二次污染。相比于物理化学修复,生物修复更加具有经济性环保性,适合用于工程上大规模的修复,有利于矿区生态长久地发展。同时对矿区重金属污染土壤治理的发展方向进行了展望,以期为有色金属矿区土壤生态环境保护提供参考。     

重金属污染土壤修复原理与技术

重金属污染会导致土壤生态结构、功能、理化性质发生改变,极大地减少农作物产量,危害生态环境和人体健康,已经成为全球主要的环境污染之一。为修复土壤重金属污染,开发了数种土壤修复技术。探讨了各种修复技术的原理、优缺点、适用性,提出了未来土壤重金属污染的研究方向应该是联合修复技术。     

某有机污染场地土壤修复方案设计

文章对华北区域某石油烃污染场地的项目基本情况及修复方案设计进行了介绍。根据前期场地调查和风险评估工作明确了场地的污染范围、方量，确定了修复目标值。经过方案比选，本场地最适合的修复技术为原地异位化学氧化修复技术。根据场调数据及修复要求，将石油烃污染土壤进行分级开展小试试验。通过小试试验知，不同污染层级的土壤分别添加4%、6%、9%比例的氧化剂(过硫酸盐)能达到本项目的修复目标要求，最终制定了场地的修复方案。     

典型金属矿区污染土壤生态修复研究与实践进展

为助推我国金属矿区污染土壤生态修复研究与治理,促进植物筛选、配置技术在矿区生态构建中的应用,对国内外金属矿区污染土壤生态修复历史发展与现状进行总结、比较,指出我国矿区污染土壤生态修复所面临的问题,简要概述矿区污染土壤的物理、化学、生物改良方法与过程,重点阐述金属矿区污染土壤生态修复研究与实践中植物选择的原则、植物的种类以及配置原则,并对矿区生态修复研究与应用的发展提出展望。     

Thermal Insulation Systems for Bioremediation in Cold Regions

Bioremediation of petroleum-contaminated soils in cold regions is hampered by low temperatures, frozen soils, and short summers. Extreme environmental conditions limit remedial efforts to a few technologies. Bioventing and combined air-sparging and soil vapor extraction have shown promise in subarctic regions. Expensive thermal desorption or encapsulation of organically contaminated soil is practiced in arctic Alaska and Canada, in lieu of successful bioremediation. Thermal insulation systems have recently been developed for innovative bioremediation efforts in cold regions. Commercially available insulation, electrical heating elements, and construction materials have been uniquely packaged to enhance bioremediation at two petroleum-contaminated sites in Alaska. Thermally enhanced bioventing successfully remediated hydrocarbon contamination in the vadose zone at a subarctic site within two years. Preliminary results from an oxygenated and fertilized biopile, actively warmed and covered with a thermal insulation system, shows promise at an arctic site. A guide for thermal insulation system design for bioremediation application in cold regions is developed.     

AMF添加与植物组合方式对黑麦草生长和铀富集效果的研究

植物-微生物联合修复因其绿色经济的特点已成为解决土壤铀污染的主要方法之一。选取小白菜(Brassica chinensis)、紫花苜蓿(Medicago sativa)与黑麦草(Lolium perenne)作为供试植物,构建植物组合,以黑麦草为研究中心,在是否添加丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF),两种铀浓度土壤条件下探究不同植物组合方式对黑麦草生长和铀元素富集效果的影响。结果表明,植物组合增加了黑麦草地上部分生长量的投入,紫花苜蓿-黑麦草-小白菜组合以及紫花苜蓿-黑麦草组合促进黑麦草地上生长,添加AMF提高了单独种植的黑麦草对铀元素的富集能力,促进了植物组合种植条件下黑麦草的生物量积累。植物组合以及植物-AMF的联合是生物修复未来的研究方向,本研究可为探索植物组合修复铀污染的土壤提供理论和实践参考。     

Microbial leaching in environmental clean-up programmes

Microbial leaching is a simple and effective technology for extracting valuable metals from low-grade ores and mineral concentrates. Besides the industrial application for raw materials supply, microbial leaching has some potential for remediation of mining sites, treatment of mineral industrial waste products, detoxification of sewage sludge and for remediation of soils and sediments contaminated with heavy metals. There is no routine treatment for toxic metals dispersed in solid materials, and autotrophic and heterotrophic leaching processes may be considered for environmental clean-up programmes. The problems of bioremediation for heavy metal-contaminated sites are very different from those of bioremediation for organic pollution, but intensive interdisciplinary collaboration in basic and applied research in this economically important field is expected to be very beneficial in the near future. It would be ideal if the bioremediation system maximised the extent and rate of degradation of waste materials, simultaneously minimising the level of toxic substances during the operation.     

Integrated Subsurface Modeling and Risk Assessment of Petroleum-Contaminated Sites in Western Canada

Soil and groundwater contamination can pose a variety of impacts and risks to communities. Identification of management schemes with sound environmental and socio-economic efficiencies is desired. Before any decisions regarding site remediation actions can be made, three major questions may have to be answered. They are namely “What happened underground?”, “What will happen in the future under the given remediation scenarios?”, and “Are there specific risks to the surrounding community?”. In this study, an integrated modeling and risk assessment method is developed for effectively managing petroleum-contaminated sites through technically answering the above questions. It presents an integral concept that integrates issues of multicontaminant transport simulation, biodegradation modeling, health risk assessment, and site remediation for real-world problems within a general decision support framework. The developed method is applied to a petroleum-contaminated groundwater system in western Canada for identifying cost-effective management schemes with improved environmental and socio-economic efficiencies. The research outputs are directly useful for the decision maker to gain insight into the site and to make remediation decisions.     

Improved Real-Coded GA for Groundwater Bioremediation

Cost-effective ways of remediating contaminated ground water by in situ bioremediation or other methods can be identified by coupling optimization and simulation methods. However, application of these methods to field-scale problems is limited by computational efficiency and by ease of use. In this paper, a more efficient genetic algorithm is developed and applied to in situ bioremediation of ground water. The algorithm involves a real-coded genetic algorithm (GA) coupled with two newly developed operators: directive recombination and screened replacement. This paper is the first application of a real-coded genetic algorithm (RGA) to ground-water remediation. The numerical results obtained for two bioremediation examples indicate that the directive recombination and screened replacement significantly improve the performance of RGA and that RGA performs much better than the standard binary-coded GA for the ground-water remediation problem. Because of the incorporation of interactions between the degrading microbes, oxygen, and contaminant concentrations, the equations for bioremediation are highly nonlinear. The RGA developed would also be expected to be more efficient for other highly nonlinear water resources problems.     

Fuzzy Geographic Information Systems for Phytoremediation Plant Selection

Geographic information systems (GIS) technology was combined with fuzzy logic to construct a phytoremediation plant selection tool. Phytoremediation involves the use of vegetation for treatment of contaminated soils, sediments, and water. In this paper, the focus is on one particular phytoremediation mechanism plant-assisted bioremediation of polycyclic aromatic hydrocarbon (PAH) soil contamination. Many plants show potential for PAH remediation, but factors such as growth requirements, climate, and soil conditions need to be considered. Given the spatial nature of the data involved, GIS was chosen as the basis for the plant selection tool. Eight candidate plants were selected because of their PAH phytoremediation potential, and their growth requirements were represented using fuzzy membership functions to account for parameters’ uncertainty. Vermont and South Carolina were selected as case studies, and calculations were performed to determine the suitability ratings for each of the candidate plants in these areas based on the plants’ growth requirements with respect to climate and soil attributes.     

Initial-phase optimization for bioremediation of munition compound-contaminated soils

We examined the bioremediation of soils contaminated with the munition compounds 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine, and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine by a procedure that produced anaerobic conditions in the soils and promoted the biodegradation of nitroaromatic contaminants. This procedure consisted of flooding the soils with 50 mM phosphate buffer, adding starch as a supplemental carbon substrate, and incubating under static conditions. Aerobic heterotrophs, present naturally in the soil or added as an inoculum, quickly removed the oxygen from the static cultures, creating anaerobic conditions. Removal of parent TNT molecules from the soil cultures by the strictly anaerobic microflora occurred within 4 days. The reduced intermediates formed from TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine were removed from the cultures within 24 days, completing the first stage of remediation. The procedure was effective over a range of incubation temperatures, 20 to 37 degrees C, and was improved when 25 mM ammonium was added to cultures buffered with 50 mM potassium phosphate. Ammonium phosphate buffer (50 mM), however, completely inhibited TNT reduction. The optimal pH for the first stage of remediation was between 6.5 and 7.0. When soils were incubated under aerobic conditions or under anaerobic conditions at alkaline pHs, the TNT biodegradation intermediates polymerized. Polymerization was not observed at neutral to slightly acidic pHs under anaerobic conditions. Completion of the first stage of remediation of munition compound-contaminated soils resulted in aqueous supernatants that contained no munition residues or aminoaromatic compounds.     

铀矿区放射性污染土壤修复技术研究进展

放射性核素导致的土壤污染受到人们的日益关注,铀矿山生产引起的矿区生态环境污染治理与修复已成为环保行业研究热点。铀矿区核素污染土壤修复技术包括物理修复技术、化学修复技术和生物修复等。土壤挖掘、覆盖和清洗是应对突发事件的首选方法,可发挥拓展污染场地的实际利用功能。对复杂的污染场地应当根据实际情况,发挥多学科交叉的作用,制定具有成本效益和环境友好的不同的修复技术方案,成为铀矿区放射性污染土壤修复技术的主流选择。系统总结了物理修复技术、化学修复技术和生物修复技术的基础理论、作用机制和发展现状,探讨对不同场地修复需求制定特定的修复方案路径,展望铀矿区核素污染土壤修复标准制定方向,为铀矿区放射性核素铀污染土壤修复提供理论支撑和指导依据。     

基于文献计量的土壤污染修复研究热点与发展趋势

为全面准确了解国内外土壤污染修复领域的研究进展与布局,基于Web of Science核心合集(WOSCC)数据库并结合文献计量学方法和可视化分析软件探讨了该领域近30年来的研究现状、研究热点及发展趋势。结果表明,世界范围内土壤污染修复领域年度发文量呈快速增长态势,我国在该研究领域虽起步较晚,但发展迅速,并于2009年成为该领域年度发文量最高的国家。研究机构以中国科学院发文量和被引频次最多且总联系强度最大,表明中国科学院在土壤污染修复研究方面具有显著影响力和较强的活跃度。关键词热点分析结果显示,当前土壤污染修复研究主要侧重于重金属和多环芳烃污染土壤修复,修复技术则以植物修复、生物修复、生物降解为研究热点。微生物修复、生物炭钝化等绿色高效修复技术是当下及未来土壤污染修复领域的发展方向和研究热点。