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Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes

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 thr...

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Autores principales: Chapman, Steven, Parker, Beth, Al, Tom, Wilkin, Richard, Cutt, Diana, Mishkin, Katherine, Nelson, Shane
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8809365/
https://www.ncbi.nlm.nih.gov/pubmed/35118346
http://dx.doi.org/10.3390/soilsystems5010018
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author Chapman, Steven
Parker, Beth
Al, Tom
Wilkin, Richard
Cutt, Diana
Mishkin, Katherine
Nelson, Shane
author_facet Chapman, Steven
Parker, Beth
Al, Tom
Wilkin, Richard
Cutt, Diana
Mishkin, Katherine
Nelson, Shane
author_sort Chapman, Steven
collection PubMed
description 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.
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spelling pubmed-88093652022-02-02 Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes Chapman, Steven Parker, Beth Al, Tom Wilkin, Richard Cutt, Diana Mishkin, Katherine Nelson, Shane Soil Syst Article 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. 2021-03-16 /pmc/articles/PMC8809365/ /pubmed/35118346 http://dx.doi.org/10.3390/soilsystems5010018 Text en https://creativecommons.org/licenses/by/4.0/This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.
spellingShingle Article
Chapman, Steven
Parker, Beth
Al, Tom
Wilkin, Richard
Cutt, Diana
Mishkin, Katherine
Nelson, Shane
Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes
title Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes
title_full Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes
title_fullStr Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes
title_full_unstemmed Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes
title_short Field, Laboratory and Modeling Evidence for Strong Attenuation of a Cr(VI) Plume in a Mudstone Aquifer Due to Matrix Diffusion and Reaction Processes
title_sort field, laboratory and modeling evidence for strong attenuation of a cr(vi) plume in a mudstone aquifer due to matrix diffusion and reaction processes
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8809365/
https://www.ncbi.nlm.nih.gov/pubmed/35118346
http://dx.doi.org/10.3390/soilsystems5010018
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