Rogers Shane W, Ong Say Kee, Moorman Thomas B
Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA 50011, USA.
Chemosphere. 2007 Nov;69(10):1563-73. doi: 10.1016/j.chemosphere.2007.05.058. Epub 2007 Jul 6.
The microbial community structure and mineralization of polycyclic aromatic hydrocarbons (PAHs) in a coal-tar contaminated aquifer were investigated spatially using fluorescence in situ hybridization (FISH) and in laboratory-scale incubations of the aquifer sediments. DAPI-detected microbial populations in the contaminated sediments were three orders of magnitude greater than nearby uncontaminated sediments, suggesting growth on coal-tar constituents in situ. Actinobacteria, beta- and gamma-Proteobacteria, and Flavobacteria dominated the in situ aerobic (>1 mg l(-1) dissolved oxygen) microbial community, whereas sulfate-reducing bacteria comprised 37% of the microbial community in the sulfidogenic region of the aquifer. Rapid mineralization of naphthalene and phenanthrene were observed in aerobic laboratory microcosms and resulted in significant enrichment of beta- and gamma-Proteobacteria potentially explaining their elevated presence in situ. Firmicutes, Flavobacteria, alpha-Proteobacteria, and Actinobacteria were also enriched in the mineralization assays, but to a lesser degree. Nitrate- and sulfate-limited mineralization of naphthalene in laboratory microcosms occurred to a small degree in aquifer sediments from locations where groundwater chemistry indicated nitrate- and sulfate-reduction, respectively. Some iron-limited mineralization of naphthalene and phenanthrene was also observed in sediments originating near groundwater measurements of elevated ferrous iron. The results of this study suggest that FISH may be a useful tool for providing a much needed link between laboratory microcosms and groundwater measurements made in situ necessary to better demonstrate the potential for natural attenuation at complex PAH contaminated sites.
利用荧光原位杂交技术（FISH）对煤焦油污染含水层中多环芳烃（PAHs）的微生物群落结构及矿化作用进行了空间研究，并对含水层沉积物进行了实验室规模的培养。DAPI检测到污染沉积物中的微生物数量比附近未受污染的沉积物高出三个数量级，表明微生物在原位利用煤焦油成分生长。放线菌、β-和γ-变形菌以及黄杆菌在原位需氧（溶解氧>1 mg l(-1)）微生物群落中占主导地位，而硫酸盐还原菌在含水层的产硫化物区域占微生物群落的37%。在需氧实验室微观环境中观察到萘和菲的快速矿化，导致β-和γ-变形菌显著富集，这可能解释了它们在原位的高丰度。厚壁菌门、黄杆菌、α-变形菌和放线菌在矿化试验中也有富集，但程度较小。在分别显示硝酸盐和硫酸盐还原的地下水化学特征的地点采集的含水层沉积物中，实验室微观环境中萘的硝酸盐和硫酸盐限制矿化程度较小。在亚铁离子含量升高的地下水测量点附近采集的沉积物中，也观察到了一些萘和菲的铁限制矿化。本研究结果表明，FISH可能是一种有用的工具，有助于在实验室微观环境与原位地下水测量之间建立急需的联系，这对于更好地证明复杂PAH污染场地的自然衰减潜力是必要的。
