Title: Field experiments of surface water to groundwater recharge to characterize the mobility of uranium and vanadium at a former mill tailing site

Abstract

Characterizing the mobility of uranium and vanadium in groundwater with a hydraulic connection to surface water is important to inform the best management practices of former mill tailing sites. In this study, the recharge of river water to the unsaturated and saturated zones of a uranium-contaminated alluvial aquifer was simulated in a series of forced-gradient single- and multi-well injection-extraction tests. The injection fluid (river water) was traced with natural and artificial tracers that included halides, fluorobenzoates, lithium, and naphthalene sulfonate to characterize the potential mass transport mechanisms of uranium and vanadium. The extraction fluid (river water/groundwater mixture) was analyzed for the tracers, uranium, and vanadium. The results from the tracers indicated that matrix diffusion was likely negligible over the spatiotemporal scales of the tests as evident by nearly identical breakthrough curves of the halides and fluorobenzoates. In contrast, the breakthrough curves of lithium and naphthalene sulfonate indicated that sorption by cation exchange and sorption to organic matter, respectively, were potential mass transport mechanisms of uranium and vanadium. Uranium was mobilized in the saturated zone containing gypsum (gypsum-rich zone), the vadose zone (vadose-rich zone), and the saturated zone containing organic carbon (organic-rich zone) whereas vanadium was mobilized only in the saturatedmore » gypsum-rich zone. The mechanisms responsible for the mobilization of uranium and vanadium were likely dissolution of uranium- and vanadium-bearing minerals and/or desorption from the gypsum-rich zone, flushing of uranium from the vadose-rich zone, and desorption of uranium from the organic-rich zone due to the natural contrast in the geochemistry between the river water and groundwater. The experimental design of this study was unique in that it employed the use of multiple natural and artificial tracers coupled with a direct injection of native river water to groundwater. Here, these results demonstrated that natural recharge and flooding events at former mill tailing sites can mobilize uranium, and possibly vanadium, and contribute to persistent levels of groundwater contamination.« less

Authors:

Paradis, Charles Joseph ^[1]; Johnson, Raymond H. ^[2]; Tigar, Aaron D. ^[2]; Sauer, Kirsten Benedict  ^[1];

• Search DOE PAGES for author "Sauer, Kirsten Benedict"
• Search DOE PAGES for ORCID "0000-0001-7987-4584"

Marina, Oana C. ^[1]; Reimus, Paul William  ^[1]

• Search DOE PAGES for author "Reimus, Paul William"
• Search DOE PAGES for ORCID "0000-0002-7422-9540"

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Earth and Environmental Sciences Div.
2. Navarro Research and Engineering, Inc., Grand Junction, CO (United States)

Publication Date:

Tue Nov 26 00:00:00 EST 2019

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Office of Legacy Management (LM)

OSTI Identifier:

1576938

Alternate Identifier(s):

OSTI ID: 1996178

Report Number(s):

LA-UR-19-26931; LA-UR-22-33078
Journal ID: ISSN 0169-7722

Grant/Contract Number:  

89233218CNA000001

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Contaminant Hydrology

Additional Journal Information:

Journal Volume: 229; Journal Issue: C; Journal ID: ISSN 0169-7722

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; Uranium; Vanadium; Groundwater; Surface Water