Isotopic and Geochemical Analysis of Microbial Processes in Uncontaminated and Contaminated Ground Water and Sediment: Innovative Application of Radiocarbon

未受污染和受污染地下水和沉积物中微生物过程的同位素和地球化学分析：放射性碳的创新应用

• 批准号: 9975223
• 负责人: C. Marjorie Aelion
• 金额: $ 22.62万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-10-01 至 2003-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9975223&HistoricalAwards=false
• 关键词: Isotopic; Geochemical; Analysis; Microbial; Processes

Aelion, MarjorieStone, PeterMCB-9975223AbstractQuantifying biodegradation of chlorinated hydrocarbons (CHCs) in the subsurface is problematic because of the recalcitrant nature of the compounds and the complexity of the degradation processes. The overall objective of this innovative field study is to investigate in situ microbial mineralization of CHCs and naturally-occurring organic carbon in the subsurface using radiocarbon (14C), and carbon and hydrogen stable isotopes (13C and deuterium (2H)) of carbon dioxide (CO2) and methane (CH4). This research will quantify, compare and evaluate tetrachloroethylene (PCE) and trichloroethylene (TCE) biodegradation in the vadose zone and groundwater from a contaminated field site and uncontaminated adjacent area, under varying redox conditions. PCE, TCE, concentrations of their metabolites, and geochemical parameters will be measured using standard techniques (gas chromatography, spectrophotometry). In addition, sediment vadose zone CO2 and CH4, and groundwater dissolved inorganic carbon and CH4 will be collected and purified cryogenically for 14C and 13C analysis by accelerator mass spectrometry (AMS) and mass spectrometry (MS). Combining isotopic monitoring of 14C, 13C and 2H of CO2 and CH4 with limited contaminant monitoring can better differentiate between biochemical processes occurring in uncontaminated and contaminted groundwater. This technique distinguishes between CO2 and CH4 produced from natural substrate biodegradation versus CHC biodegradation, and can be used under varying and low contaminant and CO2 and CH4 concentrations. Although the use of radiocarbon in environmental biodegradation studies is relatively new, it is used commonly in geological and archeological dating. Currently, indirect evidence and measurements of microbial degradation are used to estimate the contribution of naturally-occurring bacteria to contaminant removal. Radiocarbon measurements will be used in conjunction with stable carbon measurement and metabolite monitoring to improve the detection of microbial degradation of organic pollutants in groundwater. Although this research will examine microbial degradation of chlorinated solvents used in dry cleaning and industrial applications, this technique should apply to any petroleum-derived contaminant such as polycyclic aromatic hydrocarbons (PAHs), diesel and jet fuel, heating oil and trinitrotoluene (TNT), because 14C is depleted in these compounds. The proposed research will expand the use radiocarbon as an environmental tracer and lay the groundwork for the application of this technique to other biochemical contaminant studies.This proposal was submitted in response to the Environmental Geochemistry and Biogeochemistry solicitation NSF 99-9 and is being funded jointly by the Divisions of BIO and EAR.

Aelion、MarjorieStone、PeterMCB-9975223 摘要 由于化合物的顽固性质和降解过程的复杂性，量化地下氯化烃 (CHC) 的生物降解是有问题的。 这项创新实地研究的总体目标是利用放射性碳 (14C) 以及二氧化碳 (CO2) 和甲烷 (CH4) 的碳和氢稳定同位素（13C 和氘 (2H)）来研究 CHC 和地下天然存在的有机碳的原位微生物矿化。 这项研究将在不同的氧化还原条件下量化、比较和评估渗流区和受污染现场和未受污染邻近区域的地下水中四氯乙烯 (PCE) 和三氯乙烯 (TCE) 的生物降解情况。 四氯乙烯、三氯乙烯、其代谢物浓度和地球化学参数将使用标准技术（气相色谱法、分光光度法）进行测量。 此外，沉积物包气带CO2和CH4以及地下水溶解的无机碳和CH4将被收集并低温纯化，通过加速器质谱（AMS）和质谱（MS）进行14C和13C分析。 将 CO2 和 CH4 的 14C、13C 和 2H 同位素监测与有限污染物监测相结合，可以更好地区分未受污染和受污染地下水中发生的生化过程。 该技术区分了天然底物生物降解产生的 CO2 和 CH4 与 CHC 生物降解产生的 CO2 和 CH4，并且可以在变化的低污染物以及 CO2 和 CH4 浓度下使用。 尽管放射性碳在环境生物降解研究中的应用相对较新，但它通常用于地质和考古年代测定。目前，微生物降解的间接证据和测量用于估计天然存在的细菌对污染物去除的贡献。 放射性碳测量将与稳定碳测量和代谢物监测结合使用，以改进地下水中有机污染物微生物降解的检测。 虽然这项研究将研究干洗和工业应用中使用的氯化溶剂的微生物降解，但该技术应该适用于任何石油衍生的污染物，例如多环芳烃 (PAH)、柴油和喷气燃料、取暖油和三硝基甲苯 (TNT)，因为这些化合物中的 14C 已耗尽。 拟议的研究将扩大放射性碳作为环境示踪剂的用途，并为该技术应用于其他生化污染物研究奠定基础。该提案是为了响应环境地球化学和生物地球化学征集 NSF 99-9 而提交的，并由 BIO 和 EAR 部门联合资助。