Brusseau Mark L, Guo Zhilin
School of Earth and Environmental Sciences, University of Arizona, 429 Shantz, Tucson, AZ 85721, United States.
School of Earth and Environmental Sciences, University of Arizona, 429 Shantz, Tucson, AZ 85721, United States.
J Contam Hydrol. 2014 Aug;164:16-24. doi: 10.1016/j.jconhyd.2014.05.004. Epub 2014 May 22.
Historical groundwater-withdrawal and contaminant-concentration data collected from long-term pump-and-treat operations were analyzed and used to examine contaminant mass discharge (CMD) and mass-removal behavior for multiple sites. Differences in behavior were observed, and these differences were consistent with the nature of contaminant distributions and subsurface properties of the sites. For example, while CMD exhibited a relatively rapid decline during the initial stage of operation for all three sites, the rate of decline varied. The greatest rate was observed for the PGN site, whereas the lowest rate was observed for the MOT site. In addition, the MOT site exhibited the lowest relative reduction in CMD. These results are consistent with the actuality that the MOT site likely contains the greatest proportion of poorly accessible contaminant mass, given that it comprises a combined alluvium and fractured-bedrock system in which solvent and dissolved mass are present directly in the bedrock. The relative contributions of the source zones versus the plumes to total CMD were determined. Constrained contaminant mass removal was observed to influence the plumes for all three sites, and was attributed to a combination of uncontrolled (or imperfectly controlled) sources, back diffusion, and well-field hydraulics. The results presented herein illustrate that detailed analysis of operational pump-and-treat data can be a cost-effective method for providing value-added characterization of contaminated sites.
对从长期抽提处理作业中收集的历史地下水抽取量和污染物浓度数据进行了分析，并用于研究多个场地的污染物质量排放（CMD）和质量去除行为。观察到了行为上的差异，这些差异与场地污染物分布的性质和地下特性一致。例如，虽然所有三个场地在作业初期CMD都呈现出相对快速的下降，但下降速率各不相同。PGN场地的下降速率最大，而MOT场地的下降速率最小。此外，MOT场地的CMD相对减少量最低。这些结果与以下实际情况一致，即MOT场地可能含有比例最大的难以触及的污染物质量，因为它由冲积层和裂隙基岩组成的混合系统，其中溶剂和溶解物质直接存在于基岩中。确定了源区与羽流对总CMD的相对贡献。观察到受约束的污染物质量去除对所有三个场地的羽流都有影响，这归因于未控制（或控制不完善）的源、反向扩散和井场水力学的综合作用。本文给出的结果表明，对抽提处理作业数据进行详细分析可能是一种具有成本效益的方法，可为污染场地提供增值特征描述。
