Abstract: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.