| Title: | The vapor-phase multi-stage CMD test for characterizing contaminant mass discharge associated with VOC sources in the vadose zone: Application to three sites in different lifecycle stages of SVE operations |
| Author(s): | Brusseau ML; Mainhagu J; Morrison C; Carroll KC; |
| Address: | "Soil, Water and Environmental Science Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721, United States; Hydrology and Water Resources Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721, United States. Electronic address: brusseau@email.arizona.edu. Soil, Water and Environmental Science Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721, United States. Plant and Environmental Sciences Department, New Mexico State University, United States" |
| DOI: | 10.1016/j.jconhyd.2015.05.006 |
| ISSN/ISBN: | 1873-6009 (Electronic) 0169-7722 (Print) 0169-7722 (Linking) |
| Abstract: | "Vapor-phase multi-stage contaminant mass discharge (CMD) tests were conducted at three field sites to measure mass discharge associated with contaminant sources located in the vadose zone. The three sites represent the three primary stages of the soil vapor extraction (SVE) operations lifecycle-pre/initial-SVE, mid-lifecycle, and near-closure. A CMD of 32g/d was obtained for a site at which soil vapor SVE has been in operation for approximately 6years, and for which mass removal is currently in the asymptotic stage. The contaminant removal behavior exhibited for the vapor extractions conducted at this site suggests that there is unlikely to be a significant mass of non-vapor-phase contaminant (e.g., DNAPL, sorbed phase) remaining in the advective domains, and that most remaining mass is likely located in poorly accessible domains. Given the conditions for this site, this remaining mass is hypothesized to be associated with the low-permeability (and higher water saturation) region in the vicinity of the saturated zone and capillary fringe. A CMD of 25g/d was obtained for a site wherein SVE has been in operation for several years but concentrations and mass-removal rates are still relatively high. A CMD of 270g/d was obtained for a site for which there were no prior SVE operations. The behavior exhibited for the vapor extractions conducted at this site suggest that non-vapor-phase contaminant mass (e.g., DNAPL) may be present in the advective domains. Hence, the asymptotic conditions observed for this site most likely derive from a combination of rate-limited mass transfer from DNAPL (and sorbed) phases present in the advective domain as well as mass residing in lower-permeability ('non-advective') regions. The CMD values obtained from the tests were used in conjunction with a recently developed vapor-discharge tool to evaluate the impact of the measured CMDs on groundwater quality" |
| Keywords: | "Arizona Environmental Restoration and Remediation Gases *Groundwater/analysis/chemistry Hydrology/*methods Soil/chemistry Soil Pollutants/analysis Utah Volatile Organic Compounds/*analysis Water Water Pollutants, Chemical/*analysis Water Quality Groundwat;" |
| Notes: | "MedlineBrusseau, M L Mainhagu, J Morrison, C Carroll, K C eng P42 ES004940/ES/NIEHS NIH HHS/ ES04940/ES/NIEHS NIH HHS/ Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S. Netherlands 2015/06/07 J Contam Hydrol. 2015 Aug; 179:55-64. doi: 10.1016/j.jconhyd.2015.05.006. Epub 2015 May 23" |
