1
|
Sultana R, Johnson RH, Tigar AD, Wahl TJ, Meurer CE, Hoss KN, Xu S, Paradis CJ. Contaminant mobilization from the vadose zone to groundwater during experimental river flooding events. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 265:104391. [PMID: 38936239 DOI: 10.1016/j.jconhyd.2024.104391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/08/2024] [Accepted: 06/22/2024] [Indexed: 06/29/2024]
Abstract
Natural river flooding events can mobilize contaminants from the vadose zone and lead to increased concentrations in groundwater. Characterizing the mass and transport mechanisms of contaminants released from the vadose zone to groundwater during these recharge events is particularly challenging. Therefore, conducting highly-controlled in-situ experiments that simulate natural flooding events can help increase the knowledge of where contaminants can be stored and how they can move between hydrological compartments. This study specifically targets uranium pollution, which is accompanied by high sulfate levels in the vadose zone and groundwater. Two novel experimental river flooding events were conducted that utilized added non-reactive halides (bromide and iodide) and 2,6-difluorobenzoate tracers. In both experiments, about 8 m3 of traced water from a nearby contaminant-poor river was flooded in a 3-m diameter basin and infiltrated through the vadose zone and into a contaminant-rich unconfined aquifer for an average of 10 days. The aquifer contained 13 temporary wells that were monitored for solute concentration for up to 40 days. The groundwater analysis was conducted for changes in contaminant mass using the Theissen polygon method and for transport mechanisms using temporal moments. The results indicated an increase in uranium (21 and 24%), and sulfate (24 and 25%) contaminant mass transport to groundwater from the vadose zone during both experiments. These findings confirmed that the vadose zone can store and release substantial amounts of contaminants to groundwater during flooding events. Additionally, contaminants were detected earlier than the added tracers, along with higher concentrations. These results suggested that contaminant-rich pore water in the vadose zone was transported ahead of the traced flood waters and into groundwater. During the first flooding event, elevated concentrations of contaminants were sustained, and that chloride behaved similarly. The findings implied that contaminant- and chloride-rich evaporites in the vadose zone were dissolved during the first flooding event. For the second flooding event, the data suggested that the contaminant-rich evaporites continued to dissolve whereas chloride-rich evaporites were previously flushed. Overall, these findings indicated that contaminant-rich pore water and evaporites in the vadose zone can play a significant role in contaminant transport during flooding events.
Collapse
Affiliation(s)
- Rakiba Sultana
- Department of Geosciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave, Milwaukee, WI 53211, United States.
| | - Raymond H Johnson
- RSI EnTech, LLC, Contractor to the U.S. Department of Energy Office of Legacy Management, 2597 Legacy Way, Grand Junction, CO 81503, United States
| | - Aaron D Tigar
- RSI EnTech, LLC, Contractor to the U.S. Department of Energy Office of Legacy Management, 2597 Legacy Way, Grand Junction, CO 81503, United States
| | - Timothy J Wahl
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E Greenfield Ave, Milwaukee, WI 53204, United States
| | - Cullen E Meurer
- Department of Geosciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave, Milwaukee, WI 53211, United States
| | - Kendyl N Hoss
- Department of Geosciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave, Milwaukee, WI 53211, United States
| | - Shangping Xu
- Department of Geosciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave, Milwaukee, WI 53211, United States
| | - Charles J Paradis
- Department of Geosciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave, Milwaukee, WI 53211, United States
| |
Collapse
|
2
|
Paradis CJ, Hoss KN, Meurer CE, Hatami JL, Dangelmayr MA, Tigar AD, Johnson RH. Elucidating mobilization mechanisms of uranium during recharge of river water to contaminated groundwater. JOURNAL OF CONTAMINANT HYDROLOGY 2022; 251:104076. [PMID: 36148719 DOI: 10.1016/j.jconhyd.2022.104076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/13/2022] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
The recharge of stream water below the baseflow water table can mobilize groundwater contaminants, particularly redox-sensitive and sorptive metals such as uranium. However, in-situ tracer experiments that simulate the recharge of stream water to uranium-contaminated groundwater are lacking, thus limiting the understanding of the potential mechanisms that control the mobility of uranium at the field scale. In this study, a field tracer test was conducted by injecting 100 gal (379 l) of oxic river water into a nearby suboxic and uranium-contaminated aquifer. The traced river water was monitored for 18 days in the single injection well and in the twelve surrounding observation wells. Mobilization of uranium from the solid to the aqueous phase was not observed during the tracer test despite its pre-test presence being confirmed on the aquifer sediments from lab-based acid leaching. However, strong evidence of oxidative immobilization of iron and manganese was observed during the tracer test and suggested that immobile uranium was likely in its oxidized state as U(VI) on the aquifer sediments; these observations ruled out oxidation of U(IV) to U(VI) as a potential mobilization mechanism. Therefore, desorption of U(VI) appeared to be the predominant potential mobilization mechanism, yet it was clearly not solely dependent on concentration as evident when considering that uranium-poor river water (<0.015 mg/L) was recharged to uranium-rich groundwater (≈1 mg/L). It was possible that uranium desorption was limited by the relatively higher pH and lower alkalinity of the river water as compared to the groundwater; both factors favor immobilization. However, it was likely that the immobile uranium was associated with a mineral phase, as opposed to a sorbed phase, thus desorption may not have been possible. The results of this field tracer study successfully ruled out two common mobilization mechanisms of uranium: (1) oxidative dissolution and (2) concentration-dependent desorption and ruled in the importance of advection, dispersion, and the mineral phase of uranium.
Collapse
Affiliation(s)
- Charles J Paradis
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA.
| | - Kendyl N Hoss
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Cullen E Meurer
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Jiyan L Hatami
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Martin A Dangelmayr
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Aaron D Tigar
- RSI EnTech, LLC, US Department of Energy Office of Legacy Management Support Contractor, Grand Junction, CO, USA
| | - Raymond H Johnson
- RSI EnTech, LLC, US Department of Energy Office of Legacy Management Support Contractor, Grand Junction, CO, USA
| |
Collapse
|
3
|
Paradis C, Van Ee N, Hoss K, Meurer C, Tigar A, Reimus P, Johnson R. Single-Well Injection-Drift Test to Estimate Groundwater Velocity. GROUND WATER 2022; 60:565-570. [PMID: 35156199 DOI: 10.1111/gwat.13184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
A simple algebraic equation is presented here to estimate the magnitude of groundwater velocity based on data from a single-well injection-drift test thereby eliminating the time-consuming and costly extraction phase. A volume of tracer-amended water was injected by forced-gradient into a single well followed by monitoring of the conservative solute tracers under natural-gradient conditions as their upgradient portions drifted back through the well. The breakthrough curve data from the single well during the drift phase was analyzed to determine the mean travel times of the tracers. The estimated mean upgradient travel distance back through the single well and the mean travel times of the tracers were used in a simple algebraic equation to estimate groundwater velocity. The groundwater velocity based on the single-well injection-drift test was estimated to be approximately 0.64 ft per day. Two transects of observation wells were used to monitor the natural-gradient tracer transport downgradient of the injection well. The one-dimensional, or dual-well, transport of the tracer from the injection well to the nearest downgradient observation well indicated that the groundwater velocity was 0.55 ft per day. The two-dimensional, or multi-well, transport of the center of mass of the tracers indicated that the groundwater velocity was 0.60 ft per day; the dual- and multi-well results were in excellent agreement with those from the single-well and validated the simple algebraic equation. The new single-well method presented here is relatively simple, rapid, and does not require an extraction phase.
Collapse
Affiliation(s)
- Charles Paradis
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Nathan Van Ee
- School of Freshwater Sciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Kendyl Hoss
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Cullen Meurer
- Department of Geosciences, University of Wisconsin at Milwaukee, Milwaukee, WI, USA
| | - Aaron Tigar
- RSI EnTech, LLC, US Department of Energy Office of Legacy Management Support Contractor, Grand Junction, CO, USA
| | - Paul Reimus
- Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Raymond Johnson
- RSI EnTech, LLC, US Department of Energy Office of Legacy Management Support Contractor, Grand Junction, CO, USA
| |
Collapse
|
4
|
Paradis CJ, Miller JI, Moon J, Spencer SJ, Lui LM, Van Nostrand JD, Ning D, Steen AD, McKay LD, Arkin AP, Zhou J, Alm EJ, Hazen TC. Sustained Ability of a Natural Microbial Community to Remove Nitrate from Groundwater. GROUND WATER 2022; 60:99-111. [PMID: 34490626 PMCID: PMC9290691 DOI: 10.1111/gwat.13132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 05/23/2023]
Abstract
Microbial-mediated nitrate removal from groundwater is widely recognized as the predominant mechanism for nitrate attenuation in contaminated aquifers and is largely dependent on the presence of a carbon-bearing electron donor. The repeated exposure of a natural microbial community to an electron donor can result in the sustained ability of the community to remove nitrate; this phenomenon has been clearly demonstrated at the laboratory scale. However, in situ demonstrations of this ability are lacking. For this study, ethanol (electron donor) was repeatedly injected into a groundwater well (treatment) for six consecutive weeks to establish the sustained ability of a microbial community to remove nitrate. A second well (control) located upgradient was not injected with ethanol during this time. The treatment well demonstrated strong evidence of sustained ability as evident by ethanol, nitrate, and subsequent sulfate removal up to 21, 64, and 68%, respectively, as compared to the conservative tracer (bromide) upon consecutive exposures. Both wells were then monitored for six additional weeks under natural (no injection) conditions. During the final week, ethanol was injected into both treatment and control wells. The treatment well demonstrated sustained ability as evident by ethanol and nitrate removal up to 20 and 21%, respectively, as compared to bromide, whereas the control did not show strong evidence of nitrate removal (5% removal). Surprisingly, the treatment well did not indicate a sustained and selective enrichment of a microbial community. These results suggested that the predominant mechanism(s) of sustained ability likely exist at the enzymatic- and/or genetic-levels. The results of this study demonstrated the in situ ability of a microbial community to remove nitrate can be sustained in the prolonged absence of an electron donor.
Collapse
Affiliation(s)
- Charles J. Paradis
- Department of Earth and Planetary SciencesUniversity of TennesseeKnoxvilleTN
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN
| | - John I. Miller
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN
- Bredesen CenterUniversity of TennesseeKnoxvilleTN
| | - Ji‐Won Moon
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN
| | - Sarah J. Spencer
- Biological Engineering DepartmentMassachusetts Institute of TechnologyCambridgeMA
| | - Lauren M. Lui
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCA
| | - Joy D. Van Nostrand
- Institute for Environmental Genomics, Department of Microbiology and Plant Biologyand School of Civil Engineering and Environmental Sciences, University of OklahomaNormanOK
| | - Daliang Ning
- Institute for Environmental Genomics, Department of Microbiology and Plant Biologyand School of Civil Engineering and Environmental Sciences, University of OklahomaNormanOK
| | - Andrew D. Steen
- Department of Earth and Planetary SciencesUniversity of TennesseeKnoxvilleTN
- Department of MicrobiologyUniversity of TennesseeKnoxvilleTN
| | - Larry D. McKay
- Department of Earth and Planetary SciencesUniversity of TennesseeKnoxvilleTN
| | - Adam P. Arkin
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCA
- Department of BioengineeringUniversity of CaliforniaBerkeleyCA
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biologyand School of Civil Engineering and Environmental Sciences, University of OklahomaNormanOK
| | - Eric J. Alm
- Biological Engineering DepartmentMassachusetts Institute of TechnologyCambridgeMA
| | - Terry C. Hazen
- Department of Earth and Planetary SciencesUniversity of TennesseeKnoxvilleTN
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN
- Bredesen CenterUniversity of TennesseeKnoxvilleTN
- Department of BioengineeringUniversity of CaliforniaBerkeleyCA
- Department of Civil and Environmental SciencesUniversity of TennesseeKnoxvilleTN
- Center for Environmental BiotechnologyUniversity of TennesseeKnoxvilleTN
- Institute for a Secure and Sustainable EnvironmentUniversity of TennesseeKnoxvilleTN
| |
Collapse
|
5
|
Paradis CJ, Johnson RH, Tigar AD, Sauer KB, Marina OC, Reimus PW. Field experiments of surface water to groundwater recharge to characterize the mobility of uranium and vanadium at a former mill tailing site. JOURNAL OF CONTAMINANT HYDROLOGY 2020; 229:103581. [PMID: 31810750 DOI: 10.1016/j.jconhyd.2019.103581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 11/23/2019] [Accepted: 11/24/2019] [Indexed: 06/10/2023]
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 saturated 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. 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.
Collapse
Affiliation(s)
- Charles J Paradis
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Raymond H Johnson
- Navarro Research and Engineering, Inc., Contractor to the United States Department of Energy, Office of Legacy Management, Grand Junction, CO, USA
| | - Aaron D Tigar
- Navarro Research and Engineering, Inc., Contractor to the United States Department of Energy, Office of Legacy Management, Grand Junction, CO, USA
| | - Kirsten B Sauer
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Oana C Marina
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Paul W Reimus
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| |
Collapse
|