中文摘要：

某废弃石化冶炼厂土壤及地下水污染十分严重。该研究通过钻孔取样的方法,采集了厂区内距地表约30 m深的石油污染地下水,分析了该样品的水质参数及主要石油污染物组成。同时提取水样中微生物总DNA,构建细菌16S rDNA克隆文库,并通过16S rDNA序列的系统发育分析,对样品中的降解菌群落结构进行了研究。结果表明,该地下水样品中的污染物主要为苯环类物质;水样中的降解菌则分属10个细菌类群。在这一生态系统中,α-变形杆菌纲（Alphaproteobacteria,44.2%）细菌占据主导地位,其中Altererythrobacter spp.在文库中的比例高达25.9%。据我们所知,这是首次发现Altererythrobacter属细菌存在于地下水环境中。β-变形杆菌纲（Betaproteobacteria,24.8%）和γ-变形杆菌纲（Gamaproteobacteria,20.9%）在系统中所占比例也均超过了20%,其中噬氢菌属（Hydrogenophaga）和溶杆菌属（Lysobacter）细菌所占比例分别达16.1%和15.3%。石油污染物的种类对降解菌群落结构组成有着重要的影响。

英文摘要：

Soil and groundwater sample were contaminated seriously in an abandoned petrochemical factory.A petroleumcontaminated groundwater sample was collected from an aquifer about 30m below ground surface,and water characteristics and pollutant components of the sample were determined.Microbial genome DNA was extracted for 16S rDNA gene amplification,and then a bacterial 16S rDNA gene clone library was constructed.After phylogenetic analysis of 16S rDNA sequence,degrading bacteria community structure of the groundwater was studied.Results showed benzene ring substances were main pollutants in the groundwater and degrading bacteria could be divided into 10 groups.Alphaproteobacteria were the most abundant group in the ecosystem,accounting for 44.2%,and especially Altererythrobacter spp.accounted for 25.9% of all bacteria.It is the first occasion that Altererythrobacter species were detected in the groundwater.While Betaproteobacteria and Gamaproteobacteria accounted for over 20% of total clones,within which Hydrogenophaga spp and Lysobacter spp.represented 16.1% and 15.3% of all bacteria respectively.The components of petroleum contaminant have an important effect on community structure of degrading bacteria.