Assessment of natural bioattenuation of PCE & TCE

该项目将基因探针分析与实验室和实地研究相结合，以评估一种创新的含水层修复技术——共溶剂冲洗（使用95%乙醇）对本地微生物的影响。除了研究生态系统功能指标外，该项目还将调查在最初被过氯乙烯（PCE）和三氯乙烯（TCE）污染的特定地点存在的微生物种群降解残留污染物和处理后残留降解产物的潜力。要测试的具体假设是：1)现场存在的微生物能够反弹到冲洗前识别的原始多样性和活性；2)这些反弹的微生物能够降解冲洗后残留的任何污染物和子产物，从而使场地对人体健康和环境无害。具体目标1/基因探针分析：将在处理前后测量特定的原核基因浓度，并将其用作生态和生物降解指标。然后，这些指标将与实验室特定处理有关，并将用作生态和生物降解指标。然后，这些指标将与实验室（特定目标2）和原位微观环境（特定目标3）结果相关联，以便提供评估现有群落自然降解能力的手段。具体目标2/实验室MICROCOSM研究：Microcosms将建立模型，模拟佛罗里达州杰克逊维尔一个PCE和tce污染地点在乙醇冲洗前后的环境（就氧气水平、营养物质和污染物浓度而言）。将测量并比较处理前后污染物转化和产物形成的速率（包括TCE、顺式和反式二氯乙烯（DCE）、氯乙烯（VC）、乙烯（ETH）、水合二氯乙酸氯醛等）。具体目标3/原位微环境研究：将建立原位微环境，然后放置在PCE污染场地的不同位置。将测量底物转化、产物形成和电子供体/受体利用的原位速率，并将其与实验室微观研究相比较，作为确定在现场冲洗前后存在的微生物活性的另一种评估工具。

This project will combine gene probe analysis with laboratory and field studies to assess the effect of an innovative aquifer remediation technology, co-solvent flushing (using 95% ethanol), on the indigenous microorganisms. In addition to studying indicators of ecosystems functioning, this project will also investigate the potential of the microbial populations present at a specific site originally contaminated with perchloroethylene (PCE) and trichloroethylene (TCE) to degrade residual contaminant and degradation products remaining after treatment. The specific hypotheses to be tested are: 1) microorganisms present at the site are capable of rebounding to their original diversity and activity recognized before flushing; and 2) these rebounded microorganisms are capable of degrading any contaminant and daughter products remaining after flushing, thus rendering the site harmless to human health and the environment. This proposed work has three specific aims: SPECIFIC AIM 1/GENE PROBE ANALYSIS: Specific prokaryotic gene concentrations will be measured before and after treatment and will be used as ecological and biodegradative indicators. These indicators will then be related to laboratory (Specific treatment and will be used as ecological and biodegradative indicators. These indicators will then be related to laboratory (Specific Aim 2) and in situ microcosm (Specific Aim 3) results in order to provide a means of assessing the natural degradative ability of the communities present. SPECIFIC AIM 2/LABORATORY MICROCOSM STUDIES: Microcosms will be set up to model the environment present before and after ethanol-flushing at a PCE- and TCE-contaminated site in Jacksonville, FL (in terms of oxygen levels, nutrient and contaminant concentrations). Rates of contaminant transformation and product formation (including TCE, cis- and trans-dichloroethylene (DCE), vinyl chloride (VC), ethene (ETH), chloral hydrate dichloroacetate, etc.) will be measured and compared before and after treatment. SPECIFIC AIM 3/IN SITU MICROCOSM STUDIES: In situ microcosms will be built and then placed at various locations at a PCE- contaminated site. In situ rates of substrate transformation, product formation, and electron donor/acceptor utilization will be measured and compared to the laboratory microcosm studies as another assessment tool for determining the activity of the microorganisms present before and after flushing at the site.