Characterization of Persistent Volatile Contaminant Sources in the Vadose Zone
Characterization of Persistent Volatile Contaminant Sources in the Vadose Zone
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DOI：
10.1111/gwmr.12006
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发表时间：
2013-03-01
影响因子：
1.9
通讯作者：
Rohay, Virginia J.
中科院分区：
文献类型：
--
作者：
Carroll, Kenneth C.;Truex, Michael J.;Rohay, Virginia J.
有效的长期运作的土壤蒸汽提取（SVE）系统的清除渗流区的来源需要考虑的可能性，随着时间的推移，补救活动将改变地下分布和配置的污染物。介绍了一种用于确定包气带中持久性挥发性有机污染物（VOC）源的分布和性质的方法。该方法包括三个组成部分：分析现有的网站和SVE操作数据，气相循环污染物质量排放测试，短期气相污染物质量排放测试在多个地点进行了串联。从该方法获得的结果被用来表征整体源区传质限制，源强度降低，源区结构的潜在变化，以及能源部汉福德站点的持久性源的空间变异性和范围。结果证实了污染物质量排放的非均匀分布在整个包气带。质量排放剖面的分析表明，其余的污染源是符合在现场的低渗透性单元。本文所获得的源强度和大小的这种测量是确定渗流区源对地下水污染和蒸汽侵入的影响所必需的，并且可以支持SVE操作的性能的评估和优化。
Effective long-term operation of soil vapor extraction (SVE) systems for cleanup of vadose-zone sources requires consideration of the likelihood that remediation activities over time will alter the subsurface distribution and configuration of contaminants. A method is demonstrated for locating and characterizing the distribution and nature of persistent volatile organic contaminant (VOC) sources in the vadose zone. The method consists of three components: analysis of existing site and SVE-operations data, vapor-phase cyclic contaminant mass-discharge testing, and short-term vapor-phase contaminant mass-discharge tests conducted in series at multiple locations. Results obtained from the method were used to characterize overall source zone mass-transfer limitations, source-strength reductions, potential changes in source-zone architecture, and the spatial variability and extent of the persistent source(s) for the Department of Energy's Hanford site. The results confirmed a heterogeneous distribution of contaminant mass discharge throughout the vadose zone. Analyses of the mass-discharge profiles indicate that the remaining contaminant source is coincident with a lower-permeability unit at the site. Such measurements of source strength and size as obtained herein are needed to determine the impacts of vadose-zone sources on groundwater contamination and vapor intrusion, and can support evaluation and optimization of the performance of SVE operations.