土壤多环芳烃污染根际修复研究进展

多环芳烃(polycyclicaromatichydrocarbons,PAHs)是环境中普遍存在的具有代表性的一类重要持久性有机污染物,具“三致性”、难降解性,在土壤环境中不断积累,严重危害着土壤的生产和生态功能、农产品质量和人类健康。修复土壤多环芳烃污染已成为研究的焦点。根际修复是利用植物-微生物和根际环境降解有机污染物的复合生物修复技术,是目前最具潜力的土壤生物修复技术之一。对国内外学者近年来在土壤多环芳烃污染根际修复的效果、根际修复机理和根际修复的影响因素方面的研究进展作了较系统的综述,并分别分析了单作体系、混作体系、多进程根际修复系统和接种植物生长促进菌根际修复系统对土壤多环芳烃的修复效果。指出根际环境对PAHs的修复主要有3种机制:根系直接吸收和代谢PAHs;植物根系释放酶和分泌物去除PAHs,增加根际微生物数量,提高其活性,强化微生物群体降解PAHs。并讨论了影响根际修复PAHs的环境因素如植物、土壤类型、PAHs理化性质、菌根真菌以及表面活性剂等。植物-表面活性剂结合的根际修复技术、PAHs胁迫下根际的动态调节过程、运用分子生物学技术并结合植物根分泌物的特异性筛选高效修复植物以及植物富集的PAHs代谢产物进行跟踪与风险评价将成为未来研究的主流。

Research progress in rhizoremediation on polycyclic aromatic hydrocarbons (PAHs) contaminated soil

Polycyclic aromatic hydrocarbons (PAHs), a class of persistent organic pollutants (POPs), are widely accumulated in the soil environment. Soil contamination with PAHs poses a great threat worldwide to the production and ecological function of soil, the agricultural food quality and human health due to their widespread occurrence, persistence in soil ecosystems, carcinogenic, mutagenic and not easy degradable properties. Remediate the contaminated soil with PAHs has been focused in the world. Rhizoremediation is a relatively new approach to removing organic contaminants from the environment using plant, rhizosphere microorganisms and rhizosphere environment. It is a combined bioremediation with stronger growth potential. The recent studies on efficiency, mechanisms and affecting environmental factor of PAHs rhizoremediation were reviewed. The efficiency of single plant cultivation, combined plants cultivation, multi-process rhizoremediation system, and introduction of plant growth promoting rhizobacteria (PGPR) were analysed. There were three roles and mechanisms to remove PAHs from rhizoenvironment. Root could uptake, accumulate and metabolize PAHs. Root exudates and enzyme could dissipate PAHs and stimulate the activity of rhizospheric microbes. The environmental factors affecting the rhizoremediation of PAHs, including plant, soil type, physical and chemical characters of PAHs, mycorrhizal fungi, as well as surfactant were also discussed. The use of surfactants to enhance the efficiency of rhizoremediation, the process of root regulate system under PAHs stress, choosing the highest efficiency plant with applying molecular biological technology and peculiarity of root exudates, and the track and risk assessment of metabolism of PAHs in plant will become the mainstream study of future.