Back to Search
Start Over
Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes
- Source :
- Soil systems, Soil Systems, Volume 5, Issue 1, Soil Systems, Vol 5, Iss 18, p 18 (2021)
- Publication Year :
- 2021
- Publisher :
- MDPI AG, 2021.
-
Abstract
- This study uses a combination of conventional and high resolution field and laboratory methods to investigate processes causing attenuation of a hexavalent chromium (Cr(VI)) plume in sedimentary bedrock at a former industrial facility. Groundwater plume Cr(VI) concentrations decline by more than three orders of magnitude over a 900 m distance down gradient from the site. Internal plume concentrations generally exhibit stable to declining trends due to diffusive and reactive transport in the low permeability matrix as fluxes from the contamination source dissipate due to natural depletion processes and active remediation efforts. The strong attenuation is attributed to diffusion from mobile groundwater in fractures to immobile porewater in the rock matrix, and reactions causing transformation of aqueous Cr(VI) to low-solubility Cr(III) precipitates, confirmed by high spatial resolution rock matrix contaminant concentrations and comparisons with groundwater concentrations from multi-level sampling within the plume. Field characterization data for the fracture network and matrix properties were used to inform 2-D discrete-fracture matrix (DFM) numerical model simulations that quantify attenuation due to diffusion and reaction processes, which show consistency with field datasets, and provide insights regarding future plume conditions. The combination of field, laboratory and modeling evidence demonstrates effects of matrix diffusion and reaction processes causing strong attenuation of a Cr(VI) plume in a sedimentary bedrock aquifer. This approach has important implications for characterization of sites with Cr(VI) contamination for improved site conceptual models and remediation decision-making.
- Subjects :
- Environmental remediation
0207 environmental engineering
Soil Science
reaction
Aquifer
Soil science
02 engineering and technology
010501 environmental sciences
01 natural sciences
Article
Matrix (geology)
lcsh:Chemistry
groundwater plume
Diffusion (business)
matrix diffusion
sedimentary bedrock
020701 environmental engineering
lcsh:Physical geography
attenuation
hexavalent chromium
0105 earth and related environmental sciences
Earth-Surface Processes
geography
geography.geographical_feature_category
Bedrock
6. Clean water
Plume
lcsh:QD1-999
13. Climate action
Fracture (geology)
Environmental science
lcsh:GB3-5030
Groundwater
Subjects
Details
- ISSN :
- 25718789
- Volume :
- 5
- Database :
- OpenAIRE
- Journal :
- Soil Systems
- Accession number :
- edsair.doi.dedup.....c69cf8b463e4654b26647e75b0fed364