多环芳烃污染土壤生物联合强化修复研究进展

多环芳烃(polycyclic aromatic hydrocarbons,PAHs)是广泛存在于环境中的一类有毒有机污染物。在PAHs污染土壤修复领域中,运用一些生物化学的方式来强化生物联合修复技术可以有效缩短生物修复的时间,大大提高修复效率,最具发展前景和应用价值。本文主要以植物-微生物、植物-微生物-土壤动物两种生物联合修复方式为对象,结合各自的特点、机理和实例,推断了其修复机制的内在原因,总结了影响土壤中PAHs降解效率的主要因素(包括:PAHs的浓度水平、根系分泌物的种类、外源添加降解菌和土壤动物的数量和种类、菌属或土壤动物之间的种间竞争和部分环境因素等);同时通过综述近年来国内外强化生物联合修复PAHs污染土壤的技术原理、应用成果和存在的一些问题,指出了不同情况下制约PAHs强化降解进程的潜在限制因子(包括:表面活性剂和固定化微生物的添加量、不同表面活性剂的适度混合、载体材料的性质、固定化方式的选取、土壤养分和水分含量等);并强调在进行强化修复的过程中,要注重现场应用和安全性评价,为多环芳烃污染土壤的生物联合强化修复研究提供了理论依据和技术参考。

A Review of Researches on Intensified Bio-Remediation of Polycyclic Aromatic Hydrocarbons Contaminated Soils

Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic organic pollutants, found widely in the environment. In soil, as they are strongly adsorbed on soil particles, it is hard to remedy the contaminated soil efficiently. To remedy such soils, the technique of using intensified biological methods in combination to intensify the effect may effectively shorten the time the soil needs to get remedied and improve remediation efficiency, so it is considered to be the most promising one with bright future and high application value. Based on field experiments using two kinds of intensified bioremediation methods (plants-microbes and plants-microbes-soil animals), this paper introduces systematically features, mechanisms and effects of the two methods separately, infers immanent factors of the mechanisms and summarizes major factors (such as PAHs concentration, type of root exudates, amount and type of degrading bacteria and soil animals amended into the soil, interspecific competition and some environmental factors). In the meantime, an overall review is presented of the recent studies at home and abroad on intensified bioremediation of PAHs-contaminated soil including addition of surfactants or immobilized microorganisms, and their techniques, principles, applications and problems, and potential factors that may limit the intensified degradation process of PAHs in various conditions are addressed, including amount of surfactant or PAHs immobilizing microorganism added, ratio of different surfactants in mixing, properties of carries, choice of immobilizing pattern, soil water and nutrient contents and so on. In the end, the paper emphasizes that it is essential to pay attention to field application and safety evaluation in practicing the methods, so as to provide some theoretical bases and technical references for future researches on bioremediation of PAH-contaminated soils.