...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Contaminant Hydrology >DFN-M field characterization of sandstone for a process-based site conceptual model and numerical simulations of TCE transport with degradation
【24h】

DFN-M field characterization of sandstone for a process-based site conceptual model and numerical simulations of TCE transport with degradation

机译：基于过程的场地概念模型的砂岩DFN-M场表征和退化的TCE输运的数值模拟

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Plumes of trichloroethene (TCE) with degradation products occur at a large industrial site in California where TCE as a dense non-aqueous phase liquid (DNAPL) entered the fractured sandstone bedrock at many locations beginning in the late 1940s. Groundwater flows rapidly in closely spaced fractures but plume fronts are strongly retarded relative to groundwater flow velocities owing largely to matrix diffusion in early decades and degradation processes in later decades and going forward. Multiple data types show field evidence for both biotic and abiotic dechlorination of TCE and its degradation products, resulting in non-chlorinated compounds. Analyses were conducted on groundwater samples from hundreds of monitoring wells and on thousands of rock samples from continuous core over depths ranging from 6 to 426 metres below ground surface. Nearly all of the present-day mass of TCE and degradation products resides in the water-saturated, low-permeability rock matrix blocks. Although groundwater and DNAPL flow primarily occur in the fractures, DNAPL dissolution followed by diffusion and sorption readily transfers contaminant mass into the rock matrix. The presence of non-chlorinated degradation products (ethene, ethane, acetylene) and compound specific isotope analysis (CSIA) of TCE and cis-1,2-dichloroethene (cDCE) indicate at least some complete dechlorination by both biotic and abiotic pathways, consistent with the observed mineralogy and hydrogeochemistry and with published results from crushed rock microcosms. The rock matrix contains abundant iron-bearing minerals and solid-phase organic carbon with large surface areas and long contact times, suggesting degradation processes are occurring in the rock matrix. Multiple, high-resolution datasets provide strong evidence for spatially heterogeneous distributions of TCE and degradation products with varying degrees of degradation observed only when using new methods that achieve better detection of dissolved gases (i.e., Snap Sampler (TM)) and contaminant mass stored in the low permeability rock matrix (i.e., CORE-DEN (TM)). Simulations using a discrete fracture-matrix (DFN-M) numerical model capable of rigorously simulating flow and transport in both the fractures and matrix, including interactions, show that even slow, first-order degradation rates (i.e., 5- to 20-year half-lives) informed by site-derived parameters can contribute strongly to natural attenuation, resulting in TCE plumes that become stationary in space and might even retreat after 50 to 100 years, if the DNAPL sources become depleted due to the combination of diffusion and degradation processes.
机译：带有降解产物的三氯乙烯（TCE）羽团出现在加利福尼亚的一个大型工业场所，那里的TCE作为致密的非水相液体（DNAPL）从1940年代末开始在许多位置进入了破裂的砂岩基岩。地下水在紧密分布的裂缝中快速流动，但羽流前沿相对于地下水流动速度受到严重阻碍，这主要归因于前几十年的基质扩散和后几十年及以后的退化过程。多种数据类型显示了TCE及其降解产物进行生物和非生物脱氯的现场证据，从而导致了非氯化化合物。对数百个监测井的地下水样品和连续岩心的数千个岩石样品进行了分析，深度范围为地表以下6至426米。目前，几乎所有的三氯乙烯（TCE）和降解产物都存在于水饱和的低渗透性岩石基质块中。尽管地下水和DNAPL的流动主要发生在裂缝中，但DNAPL的溶解以及随后的扩散和吸附很容易将污染物转移到岩石基质中。 TCE和顺式1,2-二氯乙烯（cDCE）的非氯化降解产物（乙烯，乙烷，乙炔）和化合物特异性同位素分析（CSIA）的存在表明，至少有一些生物和非生物途径都完成了完全脱氯，这是一致的观察到的矿物学和水文地球化学，并发表了碎石微观世界的已公布结果。岩石基质中含有丰富的含铁矿物和固相有机碳，具有较大的表面积和较长的接触时间，表明岩石基质中正在发生降解过程。多个高分辨率数据集为TCE和降解产物的空间异质分布提供了有力的证据，只有在使用能够更好地检测溶解气体（即Snap Sampler（TM））和存储在其中的污染物质量的新方法时，才能观察到不同程度的降解。低渗透性岩石基质（即CORE-DEN（TM））。使用能够严格模拟裂缝和基质中的流动和输运（包括相互作用）的离散裂缝矩阵（DFN-M）数值模型进行的模拟显示，甚至缓慢的一阶降解速率（即5至20年）如果根据扩散和降解的结合而耗尽了DNAPL的来源，那么根据现场派生的参数得出的半衰期可极大地促进自然衰减，从而导致TCE羽流在太空中变得稳定，甚至在50至100年后可能退缩。流程。

著录项

  • 来源
    《Journal of Contaminant Hydrology》 |2018年第5期|96-114|共19页
  • 作者

    Pierce Amanda A.; Chapman Steven W.; Zimmerman Laura K.; Hurley Jennifer C.; Aravena Ramon; Cherry John A.; Parker Beth L.;

  • 作者单位

    Univ Guelph, Inst Groundwater Res G360, Guelph, ON N1G 2W1, Canada;

    Univ Guelph, Inst Groundwater Res G360, Guelph, ON N1G 2W1, Canada;

    Univ Guelph, Inst Groundwater Res G360, Guelph, ON N1G 2W1, Canada;

    Univ Guelph, Inst Groundwater Res G360, Guelph, ON N1G 2W1, Canada;

    Univ Waterloo, Dept Earth & Environm Sci, Waterloo, ON N2L 3G1, Canada;

    Univ Guelph, Inst Groundwater Res G360, Guelph, ON N1G 2W1, Canada;

    Univ Guelph, Inst Groundwater Res G360, Guelph, ON N1G 2W1, Canada;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号