Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites

Geogenic chromium (Cr) and vanadium (V) contamination of groundwater in the Piedmont region of North Carolina poses threats to public health. These contaminants are naturally derived from saprolite and aquifer materials, but geochemical variability in these materials makes it difficult to predict sp...

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Main Authors: Fatai O. Balogun, Hannah R. Peel, Robert E. Austin, Ibrahim G. Okunlola, David S. Vinson, Owen W. Duckworth, Matthew L. Polizzotto
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Soil Systems
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Online Access:https://www.mdpi.com/2571-8789/8/4/127
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author Fatai O. Balogun
Hannah R. Peel
Robert E. Austin
Ibrahim G. Okunlola
David S. Vinson
Owen W. Duckworth
Matthew L. Polizzotto
author_facet Fatai O. Balogun
Hannah R. Peel
Robert E. Austin
Ibrahim G. Okunlola
David S. Vinson
Owen W. Duckworth
Matthew L. Polizzotto
author_sort Fatai O. Balogun
collection DOAJ
description Geogenic chromium (Cr) and vanadium (V) contamination of groundwater in the Piedmont region of North Carolina poses threats to public health. These contaminants are naturally derived from saprolite and aquifer materials, but geochemical variability in these materials makes it difficult to predict specific risks of Cr and V in well water. The objectives of this study were to (1) determine host phases of Cr and V in representative subsurface materials; (2) characterize contaminant binding parameters of chemically variable saprolites; and (3) examine the influence of saprolite chemistry on contaminant sorption, speciation, and phase associations. Isotherm experiments revealed that saprolite samples sorbed roughly an order of magnitude more V than Cr. Chemical extractions and synchrotron-based X-ray fluorescence showed that substantial Cr and V were bound with metal oxide/oxyhydroxides in native and Cr-and V-sorbed saprolites; however, electrostatically bound fractions were also present, representing potentially important sources of groundwater contamination. X-ray absorption-near-edge-structure spectroscopy indicated that sorbed Cr was found as reduced Cr(III), whereas sorbed V was dominated by the oxidized V(V) and intermediate V(IV) species. Results from this study could be used to help parameterize mechanistic models and improve prediction of the Cr and V contamination potential of shallow aquifers.
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spelling doaj-art-7a9942ea684a458f841bdf96e054bb8f2025-08-20T02:57:21ZengMDPI AGSoil Systems2571-87892024-12-018412710.3390/soilsystems8040127Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina SaprolitesFatai O. Balogun0Hannah R. Peel1Robert E. Austin2Ibrahim G. Okunlola3David S. Vinson4Owen W. Duckworth5Matthew L. Polizzotto6Department of Earth Sciences, University of Oregon, Eugene, OR 97403, USADepartment of Crop and Soil Science, North Carolina State University, Raleigh, NC 27695, USADepartment of Crop and Soil Science, North Carolina State University, Raleigh, NC 27695, USADepartment of Geological Sciences, University of Alabama, Tuscaloosa, AL 35487, USADepartment of Geography and Earth Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USADepartment of Crop and Soil Science, North Carolina State University, Raleigh, NC 27695, USADepartment of Earth Sciences, University of Oregon, Eugene, OR 97403, USAGeogenic chromium (Cr) and vanadium (V) contamination of groundwater in the Piedmont region of North Carolina poses threats to public health. These contaminants are naturally derived from saprolite and aquifer materials, but geochemical variability in these materials makes it difficult to predict specific risks of Cr and V in well water. The objectives of this study were to (1) determine host phases of Cr and V in representative subsurface materials; (2) characterize contaminant binding parameters of chemically variable saprolites; and (3) examine the influence of saprolite chemistry on contaminant sorption, speciation, and phase associations. Isotherm experiments revealed that saprolite samples sorbed roughly an order of magnitude more V than Cr. Chemical extractions and synchrotron-based X-ray fluorescence showed that substantial Cr and V were bound with metal oxide/oxyhydroxides in native and Cr-and V-sorbed saprolites; however, electrostatically bound fractions were also present, representing potentially important sources of groundwater contamination. X-ray absorption-near-edge-structure spectroscopy indicated that sorbed Cr was found as reduced Cr(III), whereas sorbed V was dominated by the oxidized V(V) and intermediate V(IV) species. Results from this study could be used to help parameterize mechanistic models and improve prediction of the Cr and V contamination potential of shallow aquifers.https://www.mdpi.com/2571-8789/8/4/127chromiumvanadiumgroundwater contaminationsorptionchemical extractionspectroscopy
spellingShingle Fatai O. Balogun
Hannah R. Peel
Robert E. Austin
Ibrahim G. Okunlola
David S. Vinson
Owen W. Duckworth
Matthew L. Polizzotto
Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites
Soil Systems
chromium
vanadium
groundwater contamination
sorption
chemical extraction
spectroscopy
title Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites
title_full Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites
title_fullStr Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites
title_full_unstemmed Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites
title_short Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites
title_sort sorption and phase associations of chromate and vanadate with two contrasting north carolina saprolites
topic chromium
vanadium
groundwater contamination
sorption
chemical extraction
spectroscopy
url https://www.mdpi.com/2571-8789/8/4/127
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