Integrity of clay till aquitards to DNAPL migration: Assessment using current and emerging characterization tools
| Autor: | Gary Wealthall, Annika Sidelmann Fjordbøge, Henriette Kerrn-Jespersen, Mette Martina Broholm, Torben Højbjerg Jørgensen, Bernt Grosen, Anders G. Christensen, Gry Sander Janniche |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Release site
geography geography.geographical_feature_category Chlorinated solvents Soil test 0208 environmental biotechnology Soil science Aquifer 02 engineering and technology 010501 environmental sciences Dye test 01 natural sciences 020801 environmental engineering Permeability (earth sciences) Horizontal migration Limestone aquifer Geotechnical engineering Geology 0105 earth and related environmental sciences Water Science and Technology Civil and Structural Engineering |
| Zdroj: | Fjordbøge, A S, Janniche, G S, Jørgensen, T H, Grosen, B, Wealthall, G, Christensen, A G, Kerrn-Jespersen, H & Broholm, M M 2017, ' Integrity of clay till aquitards to DNAPL migration: Assessment using current and emerging characterization tools ', Ground Water Monitoring & Remediation, vol. 37, no. 3, pp. 45-61 . https://doi.org/10.1111/gwmr.12217 |
| Popis: | Field investigations were carried out to determine the occurrence of tetrachloroethene (PCE) dense non-aqueous phase liquid (DNAPL), the source zone architecture and the aquitard integrity at a 30-50 year old DNAPL release site. The DNAPL source zone is located in the clay till unit overlying a limestone aquifer. The DNAPL source zone architecture was investigated through a multiple-lines-of-evidence approach using various characterization tools; the most favorable combination of tools for the DNAPL characterization was geophysical investigations, Membrane Interface Probe (MIP), core subsampling with quantification of chlorinated solvents, hydrophobic dye test with Sudan IV and Flexible Liner Underground Technologies (FLUTe) NAPL liners with activated carbon felt (FACT). While the occurrence of DNAPL was best determined by quantification of chlorinated solvents in soil samples supported by the hydrophobic dye tests (Sudan IV and NAPL FLUTe), the conceptual understanding of source zone architecture was greatly assisted by the indirect continuous characterization tools. Although mobile or high residual DNAPL (St >1%) only occurred in 11% of the source zone samples (intact cores), they comprised 86% of the total PCE mass. The data set, and associated data analysis, supported vertical migration of DNAPL through fractures in the upper part of the clay till, horizontal migration along high permeability features around the redox boundary in the clay till, and to some extent vertical migration through the fractures in the reduced part of the clay till aquitard to the underlying limestone aquifer. The aquitard integrity to DNAPL migration was found to be compromised at a thickness of reduced clay till of less than 2 m. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|