生物修复中有机污染物的生物可利用性

Bioavailability of organic contaminants during bioremediation

论述了土壤和地下水生物修复中有机污染物的生物可利用性。污染物的可利用性对生物修复速率和生物强化效率有重要影响。生物可利用性是指土壤和地下水中的微生物或其胞外酶对有机污染物的可接近性,它受土壤理化性质、污染物和微生物性质、污染接触时间等许多因素的综合影响。污染物的介质吸附、多相分配、老化和形成非水相基质,以及土壤微生物的吸附、过滤和沉降作用降低了污染物的可利用性。促进土壤中污染物和微生物的解吸附,增强非水相基质的溶解,加速土壤污染物与微生物之间的质量传递,可以增强污染物的可利用性和生物降解的速率。施用表面活性剂和电动力学方法可有效地增强污染物的生物可利用性。

This paper discussed the bioavailability of organic contaminants to bacteria during bioremediation of polluted soils and groundwater. The availability of organic contaminants as substrates to microorganisms in contaminated sites frequently determinates the rate of bioremediation and the efficiency of bioaugmentation. The term of bioavailability herein is referred to the accessibility of organic pollutants to bacteria or bacterial extracellular enzymes in subsurface, which is often dependent upon the combined effect of the soil physicochemical properties, the characteristics of the pollutants and bacteria in subsurface, and the contact duration of pollutans to soils, and so on. The availability of organic contaminants to bacteria is lowered mainly througth the matrix sorption, multiphase partitioning, aging or sequestration, and formation into non-aqueous phase of contaminants, and also througth the adhesion, filtration and deposition of bacteria in subsurface. Greater bioavailability and higher biodegradation rate can be produced by accelerating the desorption of sorbed pollutants and bacteria from the surface of soil particles, sitmulating the dissolution of non-aqueous phase organics into pore fluids, or enhancing the mass transfer between the contaminants and the bacteria in soils. Surfactants and electrokinetic technology, if properly used, can effectively enhance the bioavailability in the process of bioremediation.