植物-微生物修复石油烃污染土壤与根际微生态环境变化

石油烃作为一类持久性难降解有机污染物对土壤环境质量产生严重的危害。以天津大港油田原油污染土壤中筛选出的耐低温高效石油烃降解菌为靶细胞,以小麦、紫花苜蓿作为供试植物,利用盆栽试验,对植物-外源菌协同修复体系中的脱氢酶活性和土壤微生物多样性进行研究,分析其变化及其与石油烃降解率的关系。结果表明植物-微生物协同修复对石油烃具有较好的降解能力,其中小麦-固定化外源菌组具有最高的降解率,石油烃含量从最初的30 600 mg獉kg-1下降为24 300 mg獉kg-1,降解率为20.6%,并且其试验后期石油烃的降解率最大,远远高于其他时期,表现出良好的修复潜力。外源菌投加的初始阶段会迅速提高脱氢酶活性,然而这种影响随着降解时间延长而逐渐减弱。初期脱氢酶活性与总石油烃的降解存在较好的相关性,脱氢酶活性可以在一定程度上表征土壤石油烃的降解情况。微生物多样性与总石油烃降解也存在一定的相关性。

Remediation of Petroleum Hydrocarbon Contaminated Soil by Plant-Microbe and the Change of Rhizosphere Microenvironment

Petroleum hydrocarbons are persistent refractory organic pollutants and have negative effect on soil environmental quality. The plant-bacteria combined method has been extensively investigated to remediate petroleum hydrocarbon contaminated soils in recent years for its high efficiency and safety. The bacteria that has low temperature-resistance and high efficiency for petroleum hydrocarbon degradation, were screened from crude oil contaminated soil in Dagang oil field of Tianjin, and selected as target cells. Wheat and alfalfa were used as target plants, and pot experiments were applied to study the dehydrogenase activity and soil microbial biodiversity. The results showed that petroleum hydrocarbons were reduced the most in wheat-bacteria remediation group with degradation rate of 20.6%. The degradation rate at final stage was much higher than that of other periods. The dehydrogenase activity was rapidly increased in the initial stage when exogenous bacteria was added, while this activity was gradually reduced with time. Dehydrogenase activity was related to the degradation of total petroleum hydrocarbons and it can be used to characterize the degradation of petroleum hydrocarbons in soils. There is a good correlation between the microbial biodiversity and the degradation of total petroleum hydrocarbons.