Development of methods to investigate soil vapor intrusion risks for methane and BTEX compounds at ethanol-blended biofuel spill sites

乙醇混合燃料的生产、分配和使用的增长增加了意外排放到环境中的可能性。这种增加的风险给污染场地管理和补救带来了新的挑战，因为缺乏关于这些生物燃料在饱和和特别不饱和的土壤中命运的详细信息。乙醇的存在可能会增加甲烷和二氧化碳的生成潜力，增加甲烷和汽油挥发性化合物侵入土壤蒸气的风险，并产生不利于汽油降解的条件，导致这些污染物持续存在于土壤大气中。因此，了解控制乙醇混合燃料降解的过程和条件对于评估其长期环境命运以及土壤蒸气侵入建筑物和其他地下基础设施的可能性至关重要。通过这一战略项目，我们将开发和应用新的和创新的方法来表征控制土壤中生物燃料衰减的过程。特别是，我们将开展田间和实验室研究，整合先进的气体通量测量技术、土壤微生物生态和化合物特有的稳定同位素。我们将通过开发和实施新的基于过程的反应传输模型来整合这些数据。这一战略项目的结果将提供所需的工具，以确定

Growth in the production, distribution and utilization of ethanol-blended fuels has raised the probability of accidental releases to the environment. This increased risk presents new challenges for contaminated site management and remediation, as detailed information on the fate of these biofuels in saturated and particularly unsaturated soils is lacking. The presence of ethanol may enhance the potential for methane and carbon dioxide generation, increase the risk of soil vapor intrusion by methane and volatile compounds of gasoline, and generate conditions non-conducive to gasoline degradation, causing these contaminants to persist in the soil atmosphere. Understanding the processes and conditions that regulate degradation of ethanol-blended fuels is therefore critical for assessing their long-term environmental fate and the potential for soil vapor intrusion into buildings and other underground infrastructure. Through this strategic project, we will develop and apply novel and innovative approaches to characterize the processes that control attenuation of biofuels in soils. In particular, we will conduct field and laboratory studies that integrate advanced techniques for measuring gas fluxes, soil microbial ecology, and compound-specific stable isotopes. We will integrate these data through development and implementation of novel process-based reactive transport models. The results of this strategic project will provide the tools needed to determine