Contaminant Attenuation and Transport Characterization of 200-DV-1 Operable Unit Sediment Samples

Truex, Michael J.; Szecsody, James E.; Qafoku, Nikolla P.; Strickland, Christopher E.; Moran, James J.; Lee, Brady D.; Snyder, Michelle M.V.; Lawter, Amanda R.; Resch, Charles T.; Gartman, Brandy N.; Zhong, Lirong; Nims, Megan K.; Saunders, Danielle L.; Williams, Bruce A.; Horner, Jacob A.; Leavy, Ian I.; Baum, Steven R.; Christiansen, Beren B.; Clayton, Ray E.; McElroy, Erin M.; Appriou, Delphine; Tyrrell, Kimberly J.; Striluk, Miranda

doi:10.2172/1368134

Cited by 16 publications

(30 citation statements)

References 15 publications

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“…All of the experiments with an initial iodine concentration of 500 ppb iodine continued for 60 days, and all have comparable solid phase concentrations of 78-93 µg/g (Table 5). Previous experiments conducted using the same 0.1M solutions resulting in solid phase concentrations of 5.7-6.8 µg/g for 50 ppb initial I concentrations (Truex et al 2017a). With similar results across the experiments here as well as the previously conducted iodine-calcite experiments (Truex et al 2017b), it is unlikely that the concentrations of U used in these experiments had any effect (either beneficial or detrimental) on the removal of iodine by calcite precipitation.…”

Section: Iodine and Uranium Incorporation Into Calcitesupporting

confidence: 76%

“…If iodine and uranium are both incorporated into calcite, and calcite is slowly dissolving during leaching, then similar iodine and uranium release rate trends would be observed for each core. However, this was not observed in Szecsody et al 2017, Truex et al 2017a, and Lee et al 2017, as cores that leached the most iodine were not correlated with cores that leached the most uranium. The most striking difference between iodine and uranium leaching behavior was that the uranium exhibited no differences between vadose zone and aquifer cores ( Figure 3).…”

Section: Iodine and Uranium Precipitationmentioning

confidence: 77%

“…Studies of field vadose zone (Truex et al 2017a;Szecsody et al 2017) and aquifer cores (Lee et al 2017) have shown that the leached iodine mass is correlated to the leaching rate, with faster initial leaching of aqueous and adsorbed iodine followed by slower leaching from the slow dissolution of carbonates (or other phases). Sequential liquid extractions of contaminants from cores show that 50% to 80% of the iodine mass in the sediment can be dissolved by the pH 5 and pH 2.3 acetate extractions, which dissolve carbonates and other phases such as iron oxides.…”

Section: Discussionmentioning

confidence: 99%

“…Vadose zone cores collected beneath the B-, T-, and S-Complexes showed significantly different concentration trends than in the groundwater (Truex et al 2017a;Szecsody et al 2017). Whereas groundwater was predominated by iodate, iodine aqueous concentrations were predominated by iodide in the unsaturated zones.…”

Section: Iodine Species In Vadose Zone Coresmentioning

confidence: 99%

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Effect of Co-Contaminants Uranium and Nitrate on Iodine Remediation

Szecsody

Lee

Lawter

et al. 2017

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The objective of this study is to evaluate the significance of co-contaminants on the migration and transformation of iodine species in the Hanford subsurface environment. These impacts are relevant because remedies that target individual contaminants like iodine, may not only impact the fate and transport of other contaminants in the subsurface, but also inhibit the effectiveness of a targeted remedy. For example, iodine (as iodate) co-precipitates with calcite, and has been identified as a potential remedy because it immobilizes iodine. Since uranium also co-precipitates with calcite in field sediments, the presence of uranium may also inhibit iodine co-precipitation. Another potentially significant impact from co-existing contaminants is iodine and nitrate. The presence of nitrate has been shown to promote biogeochemical reduction of iodate to iodide, thereby increasing iodine species subsurface mobility (as iodide exhibits less sorption). Hence, this study reports on both laboratory batch and column experiments that investigated a) the change in iodate uptake mass and rate of uptake into precipitating calcite due to the presence of differing amounts of uranium, b) the amount of change of the iodate bio-reduction rate due to the presence of differing nitrate concentrations, and c) whether nitrite can reduce iodate in the presence of microbes and/or minerals acting as catalysts. Batch experiments were conducted to quantify coupled uranium-iodate behaviors, where iodate and uranium were either incorporation into calcite, or adsorbed to the mineral surface. Results demonstrated that the presence of uranium did not influence iodate removal from solution. However, increasing iodate concentrations enhanced uranium removal. Moreover, results indicated that a significant amount of iodate would not be removed from solution if added post-calcite precipitation. Since this result differs from uranium behavior, and multiple studies have shown that uranium incorporates into calcite, this implies that iodine mass is mainly incorporated into a different surface phase than calcite. Experiments that investigated the impact of nitrate concentrations on the iodate bio-reduction rate demonstrated that iodate occurred in eight different Hanford vadose zone and aquifer sediments under both anoxic and oxic geochemical conditions. Iodate reduction decreased twofold in the presence of 8.4 mg/L O2 or in the presence of 8.4 mg/L O2, and 27 mg/L nitrate. For 1-D column experiments under high sediment/water conditions, the presence of nitrate did not increase the observed abiotic/biotic iodate reduction rate, implying that any increase in the co-metabolic bio-reduction rate of nitrate and iodate was a small contribution. Separate experiments with a microbial isolate (Shewanella oneidensis, MR-1) or an enrichment culture with Ringold sediments were executed to evaluate the influence of nitrate on microbiallymediated iodate reduction. Sediments that were pretreated with 2% gluteraldehyde for 7 days to decrease microbial activity and resulted...

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Section: Iodine and Uranium Incorporation Into Calcitesupporting

confidence: 76%

Section: Iodine and Uranium Precipitationmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Iodine Species In Vadose Zone Coresmentioning

confidence: 99%

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Effect of Co-Contaminants Uranium and Nitrate on Iodine Remediation

Szecsody

Lee

Lawter

et al. 2017

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“…Available sediments from 200-DV-1 OU characterization activities included collection of samples from some locations previously investigated as part of technology development (e.g., associated with waste similar to the 241-BX-102 samples used in URGS technology development). The observed uranium concentrations and mobility in sediments characterized during the 200-DV-1 OU effort were low in almost all of these samplesTruex et al 2017; Demirkanli et al 2018). Sediment samples for acidic waste disposal sites will not become available until new boreholes are installed and samples are collected at waste sites for 200-WA-1 OU characterization efforts.…”

mentioning

confidence: 97%

Deep Vadose Zone Treatability Test of Uranium Reactive Gas Sequestration for the Hanford Central Plateau: Final Report

Truex

Szecsody

Strickland

et al. 2018

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Over decades of operation, the U.S. Department of Energy (DOE) and its predecessors have released nearly 2 trillion L (450 billion gal.) of liquid into the vadose zone at the Hanford Site. Much of this liquid waste discharge into the vadose zone occurred in the Central Plateau, a 200 km 2 (75 mi 2 ) area that includes approximately 800 waste sites. Some of the inorganic and radionuclide contaminants in the deep vadose zone at the Hanford Site are at depths where direct exposure pathways (human health or ecological) are not of concern, but the contamination may need to be remediated to protect groundwater. The Tri-Party Agencies (DOE, the U.S. Environmental Protection Agency, and the Washington State Department of Ecology) established Milestone M-015-50, which directed DOE to submit a treatability test plan for remediation of technetium-99 (Tc-99) and uranium in the deep vadose zone. These contaminants are mobile in the subsurface environment and have been detected at high concentrations deep in the vadose zone, and, at some locations, have reached groundwater. Testing of technologies to remediate Tc-99 and uranium will also provide information relevant to remediating other contaminants in the vadose zone. The uranium reactive gas sequestration (URGS) test described herein was conducted as an element of the deep vadose zone treatability test plan published to meet Milestone M-015-50. The URGS technology was tested as a potential remedy to decrease the mobility of uranium in the vadose zone as a mechanism to protect groundwater. Information about URGS obtained from this test is intended for use in subsequent feasibility studies for Hanford Central Plateau waste sites with uranium contamination in the deep vadose zone.

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Development of a vadose zone advanced monitoring system: Tools to assess groundwater vulnerability

Linneman

Strickland

Appriou

et al. 2022

Vadose Zone Journal

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Performing repeat pore‐fluid sampling over long time‐scales can provide valuable information on unsaturated zone contaminants and their potential flux to ground water. This information can be used to manage groundwater remedies and identify contaminants that need to be sequestered in the vadose zone to minimize flux to ground water. Pore‐water samples are commonly used to obtain contaminant concentrations within the vadose zone, but existing methods are limited as they only provide a single sample at one location and time. The vadose zone advanced monitoring system (VZAMS) has been designed to integrate multiple technologies into a single down‐borehole system that allows for sampling of pore fluids (liquid and gas) to provide information about contamination and hydraulic conditions at multiple depths (∼0.3‐m intervals) within a cased borehole. Testing has been completed at the laboratory scale to verify the sampling elements of VZAMS, including geochemical testing for representative contaminants known to exist at the Hanford Site, located in southeastern Washington State. Physical tests focused on the ability of the sampler to draw fluid under unsaturated conditions. Initial geochemical testing showed that the stainless steel material used with the porous cuff may affect the sampled concentrations of redox‐sensitive contaminants under very dry conditions. Additional laboratory testing demonstrated that the VZAMS components are able to collect representative samples for substances of interest under expected field conditions. In this paper, the design and functionality of a novel instrument are demonstrated in support of subsequent testing in the field.

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Contaminant Attenuation and Transport Characterization of 200-DV-1 Operable Unit Sediment Samples

Cited by 16 publications

References 15 publications

Effect of Co-Contaminants Uranium and Nitrate on Iodine Remediation

Effect of Co-Contaminants Uranium and Nitrate on Iodine Remediation

Deep Vadose Zone Treatability Test of Uranium Reactive Gas Sequestration for the Hanford Central Plateau: Final Report

Development of a vadose zone advanced monitoring system: Tools to assess groundwater vulnerability

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