Watson Ian A, Oswald Sascha E, Mayer K Ulrich, Wu Youxian, Banwart Steven A
Groundwater Protection and Restoration Group, Department of Civil and Structural Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom.
Environ Sci Technol. 2003 Sep 1;37(17):3910-9. doi: 10.1021/es020242u.
Groundwater contaminants may degrade via fermentation to intermediate species, which are subsequently consumed by terminal electron-accepting processes (TEAPs). A numerical model of an aquifer-derived laboratory microcosm is developed to simulate the dynamic behavior of fermentation and respiration in groundwater by coupling microbial growth and substrate utilization kinetics with a formulation that also includes aqueous speciation and other geochemical reactions including surface complexation, mineral dissolution, and precipitation. The model is used to test approaches that currently make use of H2(aq) to diagnose prevalent TEAPs in groundwater. Competition between TEAPs is integral to the conceptual model of the simulation, and the results indicate that competitive exclusion is significant but with some overlap found in the temporal sequence of TEAPs. Steady-state H2(aq) concentrations observed during different TEAPs do not differ significantly. The results are not consistent with previous applications of the partial equilibrium approach since most TEAP redox pairs exhibit free energies that suggest a particular process is able to proceed, yet observations here show that this process does not proceed.
地下水污染物可能通过发酵降解为中间物种，这些中间物种随后会被末端电子接受过程（TEAPs）消耗。开发了一个源自含水层的实验室微观模型的数值模型，通过将微生物生长和底物利用动力学与一个还包括水相形态以及其他地球化学反应（包括表面络合、矿物溶解和沉淀）的公式相结合，来模拟地下水中发酵和呼吸的动态行为。该模型用于测试目前利用溶解态氢气（H2(aq)）来诊断地下水中普遍存在的TEAPs的方法。TEAPs之间的竞争是模拟概念模型的一个组成部分，结果表明竞争排斥作用显著，但在TEAPs的时间序列中发现有一些重叠。在不同的TEAPs过程中观察到的稳态溶解态氢气（H2(aq)）浓度没有显著差异。这些结果与部分平衡方法的先前应用不一致，因为大多数TEAP氧化还原对的自由能表明某个特定过程能够进行，但此处的观察结果表明该过程并未发生。
