Dissolution of Mn-bearing dolomite drives elevated Cr(vi) occurrence in a Permian redbed aquifer
Westrop, Jeffrey P. Tomlinson, Zachary D. Maples, Brandon M. Dee, Kato T. Swindle, Andrew L. Elwood Madden, Megan E. Hu, Qinhong Elwood Madden, Andrew S.
Westrop, Jeffrey P.
Tomlinson, Zachary D.
Maples, Brandon M.
Dee, Kato T.
Swindle, Andrew L.
Elwood Madden, Megan E.
Hu, Qinhong
Elwood Madden, Andrew S.
Citations
Altmetric:
Other Names
Location
Time Period
Advisors
Original Date
Digitization Date
Issue Date
2022-11-09
Type
Article
Genre
Keywords
Subjects (LCSH)
Citation
Westrop, J. P., Tomlinson, Z. D., Maples, B. M., Dee, K. T., Swindle, A. L., Elwood Madden, M. E., . . . Elwood Madden, A. S. (2022). Dissolution of Mn-bearing dolomite drives elevated Cr(vi) occurrence in a Permian redbed aquifer [10.1039/D2EM00395C]. Environmental Science: Processes & Impacts. https://doi.org/10.1039/D2EM00395C
Abstract
Municipalities in central Oklahoma, U.S.A. increasingly rely on water drawn from the Central Oklahoma Aquifer (COA) as surface water resources have not grown in proportion to population and current water demands. However, water drawn from certain regions of the COA frequently contains elevated levels of naturally occurring hexavalent chromium. Rock samples from the Norman Arsenic Test Hole Core (NATHC) were investigated to identify the mineralogic host(s) of Cr and mechanisms of Cr(vi) release via bulk mineralogy and chemistry measurements, selective chemical extractions, and microscale elemental analyses. Results demonstrate most COA Cr is contained in Fe oxides and clays as isomorphic substitutions for Fe(iii). Analyses of regional groundwater data, including hierarchical clustering methods and GIS, demonstrate the most intense Cr(vi) occurrence is linked to cation exchange with Na-clays at depth. Cation exchange allows dissolution of Mn-bearing dolomite, which in turn produces Mn oxides in otherwise dolomite-saturated groundwaters. Mn oxides in turn are known to oxidize Cr(iii) to Cr(vi). In general, co-occurrence of Mn-bearing carbonates and exchangeable clays in any aquifer, particularly those with Cr(iii) present in iron oxide cements, serve as ingredients for groundwater occurrences of oxidizable trace metals.
Table of Contents
Description
Click on the DOI to access this article (may not be free).
Publisher
The Royal Society of Chemistry
Journal
Book Title
Series
Environmental Science: Processes & Impacts
2022
2022
Digital Collection
Finding Aid URL
Use and Reproduction
Archival Collection
PubMed ID
DOI
ISSN
2050-7887