Estimating Persistent Mass Flux of Volatile Contaminants from the Vadose Zone to Ground Water
Contaminants may persist for long time periods within low permeability portions of the vadose zone where they cannot be effectively treated and are a potential continuing source of contamination to groundwater. Setting appropriate vadose zone remediation goals requires evaluating these persistent sources in terms of their impact on meeting groundwater remediation goals. One-dimensional approaches for estimating transport of volatile contaminants in the vadose zone are considered and compared to a one-dimensional flux-continuity-based assessment of vapor-phase contaminant movement from the vadose zone to the groundwater. The flux-continuity-based assessment demonstrates that the ability of the groundwater to move contaminant away from the water table controls the vapor-phase mass flux from the vadose zone across the water table. Limitations of the one-dimensional approaches are then discussed with respect to the need for further method development and application of two- or three-dimensional numerical modeling. The carbon tetrachloride (CT) plume at the U.S. Department of Energy Hanford Site is used as an example of a site where persistent vadose zone contamination needs to be considered in the context of groundwater remediation.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 963591
- Report Number(s):
- PNNL-SA-62637; 830403000
- Journal Information:
- Ground Water Monitoring and Remediation, 29(2):63-72, Journal Name: Ground Water Monitoring and Remediation, 29(2):63-72 Journal Issue: 2 Vol. 29; ISSN GWMREV; ISSN 1069-3629
- Country of Publication:
- United States
- Language:
- English
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