Feris Kevin, Mackay Doug, de Sieyes Nick, Chakraborty Irina, Einarson Murray, Hristova Krassimira, Scow Kate
Department of Biology, Boise State University, Boise, Idaho, USA.
Environ Sci Technol. 2008 Apr 1;42(7):2289-94. doi: 10.1021/es702603q.
Ethanol (EtOH) is a commonly used fuel oxygenate in reformulated gasoline and is an alternative fuel and fuel supplement. Effects of EtOH release on aquifer microbial ecology and geochemistry have not been well characterized in situ. We performed a controlled field release of petroleum constituents (benzene (B), toluene (T), o-xylene (o-X) at approximately 1-3 mg/L each) with and without EtOH (approximately 500 mg/L). Mixed linear modeling (MLM) assessed effects on the microbial ecology of a naturally sulfidic aquifer and how the microbial community affected B, T, and o-X plume lengths and aquifer geochemistry. Changes in microbial community structure were determined by quantitative polymerase chain reaction (qPCR) targeting Bacteria, Archaea, and sulfate reducing bacteria (SRB); SRB were enumerated using a novel qPCR method targeting the adenosine-5'-phosphosulfate reductase gene. Bacterial and SRB densities increased with and without EtOH-amendment (1-8 orders of magnitude). Significant increases in Archaeal species richness; Archaeal cell densities (3-6 orders of magnitude); B, T, and o-X plume lengths; depletion of sulfate; and induction of methanogenic conditions were only observed with EtOH-amendment MLM supported the conclusion that EtOH-amendment altered microbial community structure and function, which in turn lowered the aquifer redox state and led to a reduction in bioattenuation rates of B, T, and o-X.
乙醇（EtOH）是一种常用于新配方汽油中的燃料含氧化合物，也是一种替代燃料和燃料添加剂。乙醇释放对含水层微生物生态和地球化学的影响在原位尚未得到充分表征。我们进行了一次受控的现场释放实验，释放了石油成分（苯（B）、甲苯（T）、邻二甲苯（o-X），每种浓度约为1-3毫克/升），其中一组添加了乙醇（约500毫克/升），另一组未添加。混合线性模型（MLM）评估了对天然含硫含水层微生物生态的影响，以及微生物群落如何影响B、T和o-X羽流长度和含水层地球化学。通过针对细菌、古菌和硫酸盐还原菌（SRB）的定量聚合酶链反应（qPCR）确定微生物群落结构的变化；使用一种针对腺苷-5'-磷酸硫酸还原酶基因的新型qPCR方法对SRB进行计数。无论是否添加乙醇，细菌和SRB密度均增加（1-8个数量级）。仅在添加乙醇的情况下，观察到古菌物种丰富度显著增加；古菌细胞密度增加（3-6个数量级）；B、T和o-X羽流长度增加；硫酸盐消耗；以及产甲烷条件的诱导。MLM支持了这样的结论，即添加乙醇改变了微生物群落结构和功能，进而降低了含水层的氧化还原状态，并导致B、T和o-X的生物衰减率降低。
