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Intercomparison of determining diffusion coefficients of I− in compacted bentonite using various mathematical models of through-diffusion experiments in the laboratory. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-08041-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Jaquenoud M, Elam WT, Grundl T, Gimmi T, Jakob A, Schefer S, Cloet V, De Cannière P, Van Loon LR, Leupin OX. In-situ X-ray fluorescence to investigate iodide diffusion in opalinus clay: Demonstration of a novel experimental approach. CHEMOSPHERE 2021; 269:128674. [PMID: 33228984 DOI: 10.1016/j.chemosphere.2020.128674] [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: 06/09/2020] [Revised: 10/04/2020] [Accepted: 10/16/2020] [Indexed: 06/11/2023]
Abstract
During the last two decades, the Mont Terri rock laboratory has hosted an extensive experimental research campaign focusing on improving our understanding of radionuclide transport within Opalinus Clay. The latest diffusion experiment, the Diffusion and Retention experiment B (DR-B) has been designed based on an entirely different concept compared to all predecessor experiments. With its novel experimental methodology, which uses in-situ X-ray fluorescence (XRF) to monitor the progress of an iodide plume within the Opalinus Clay, this experiment enables large-scale and long-term data acquisition and provides an alternative method for the validation of previously acquired radionuclide transport parameters. After briefly presenting conventional experimental methodologies used for field diffusion experiments and highlighting their limitations, this paper will focus on the pioneer experimental methodology developed for the DR-B experiment and give a preview of the results it has delivered thus far.
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Affiliation(s)
- Max Jaquenoud
- National Cooperative for the Disposal of Radioactive Waste (NAGRA), Hardstrasse 73, 5430, Wettingen, Switzerland.
| | - William T Elam
- Applied Physics Lab, University of Washington, Seattle, WA, 98105, USA
| | - Tim Grundl
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, WI, 53201, USA
| | - Thomas Gimmi
- Institute of Geological Sciences, University of Bern, 3012, Bern, Switzerland; Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland
| | - Andreas Jakob
- Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland
| | - Senecio Schefer
- Swisstopo, Route de la Gare 63, 2882, St-Ursanne, Switzerland
| | - Veerle Cloet
- Arcadis, Ifangstrasse 11, 8952, Schlieren, Switzerland
| | | | - Luc R Van Loon
- Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland
| | - Olivier X Leupin
- National Cooperative for the Disposal of Radioactive Waste (NAGRA), Hardstrasse 73, 5430, Wettingen, Switzerland
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Neeway JJ, Kaplan DI, Bagwell CE, Rockhold ML, Szecsody JE, Truex MJ, Qafoku NP. A review of the behavior of radioiodine in the subsurface at two DOE sites. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 691:466-475. [PMID: 31323591 DOI: 10.1016/j.scitotenv.2019.07.146] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 06/10/2023]
Abstract
Multiple processes affect the fate of the radioactive isotope 129I in the environment. Primary categories of these processes include electron transfer reactions mediated by minerals and microbes, adsorption to sediments, interactions with organic matter, co-precipitation, and volatilization. A description of dominant biogeochemical processes is provided to describe the interrelationship of these processes and the associated iodine chemical species. The majority of the subsurface iodine fate and transport studies in the United States have been conducted at U.S. Department of Energy (DOE) sites where radioisotopes of iodine are present in the environment and stored waste. The DOE Hanford Site and Savannah River Site (SRS) are used to illustrate how the iodine species and dominant processes at a site are controlled by the prevailing site biogeochemical conditions. These sites differ in terms of climate (arid vs. sub-tropical), major geochemical parameters (e.g., pH ~7.5 vs. 4), and mineralogy (carbonate vs. Fe/Al oxide dominated). The iodine speciation and dominant processes at a site also have implications for selection and implementation of suitable remedy approaches for 129I.
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Affiliation(s)
- James J Neeway
- Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Daniel I Kaplan
- Savannah River National Laboratory, Aiken, SC, United States of America
| | | | - Mark L Rockhold
- Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - James E Szecsody
- Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Michael J Truex
- Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Nikolla P Qafoku
- Pacific Northwest National Laboratory, Richland, WA, United States of America.
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Xue X, Li J, Xie X, Qian K, Wang Y. Impacts of sediment compaction on iodine enrichment in deep aquifers of the North China Plain. WATER RESEARCH 2019; 159:480-489. [PMID: 31128472 DOI: 10.1016/j.watres.2019.05.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/05/2019] [Accepted: 05/11/2019] [Indexed: 06/09/2023]
Abstract
To understand the effects of large-scale sediment compaction on iodine enrichment in the groundwater system of the North China Plain (NCP), hydrogeochemical and isotope (2H, 18O and 87Sr/86Sr) geochemical features of groundwater, seawater and pore water of the deep aquifer sediments were characterized. Groundwater iodine concentration ranged from 5.8 to 1110 μg/L and approximately 80% of groundwater samples have iodine concentration more than 100 μg/L. High iodine groundwater (>100 μg/L) is mainly distributed in the Bohai bay area where serious land subsidence occurs. The sediments deposited during several events of marine transgression are considered as the main source of groundwater iodine. The pore solution compacted from the clayey sediments has a iodine concentration up to 830 μg/L, indicating that marine source iodine was stored in the clayey layers. The hydrogen and oxygen isotope signatures of groundwater show that the groundwater from NCP is mainly recharged by precipitation and the pore water from sediment compaction due to intense land subsidence. The Cl/Br molar ratio and 87Sr/86Sr signatures of groundwater and sediment pore water further suggest the effects of mixing with compaction-released pore solution on the hydrochemical evolution of high iodine groundwater. Based on groundwater δ2H, Cl concentration and 87Sr/86Sr, the results of two end-members mixing model calculation indicate that the compaction-released pore solution contributes approximately 49.1-68.9% iodine to high iodine groundwater, and the iodine from compaction-released pore solution ranges between 407 and 572 μg/L. The results of this study therefore suggest that the compaction of clayey sediments can be a major hydrogeological process controlling the genesis of high iodine groundwater in deep aquifers at NCP.
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Affiliation(s)
- Xiaobin Xue
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Junxia Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; Laboratory of Basin Hydrology and Wetland Eco-restoration, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Xianjun Xie
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; Laboratory of Basin Hydrology and Wetland Eco-restoration, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Kun Qian
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Yanxin Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
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Li J, Zhou H, Qian K, Xie X, Xue X, Yang Y, Wang Y. Fluoride and iodine enrichment in groundwater of North China Plain: Evidences from speciation analysis and geochemical modeling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 598:239-248. [PMID: 28441602 DOI: 10.1016/j.scitotenv.2017.04.158] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/14/2017] [Accepted: 04/20/2017] [Indexed: 06/07/2023]
Abstract
To better understand the enrichment of fluoride and iodine in groundwater at North China Plain (NCP), speciation analysis and geochemical modeling were conducted to identify the key hydrochemical processes controlling their mobilization in groundwater system. Groundwater fluoride and iodine concentrations ranged from 0.18 to 5.59mg/L and from 1.51 to 1106μg/L, respectively, and approximately 63% and 32.3% of groundwater fluoride and iodine were higher than the guidelines for drinking water (1.5mg/L and 150μg/L). High fluoride concentration (>1.5mg/L) can be detected in groundwater from the flow-through and discharge areas of NCP, and high iodine groundwater (>150μg/L) is mainly scattered in the coastal area. Na-HCO3/Cl type water resulted from water-rock interaction and seawater intrusion favors fluoride and iodine enrichment in groundwater. Speciation analysis results indicate that (1) fluoride complexes in groundwater are dominated by free fluoride, the negative charge of which favors fluoride enrichment in groundwater under basic conditions, and (2) iodide, iodate and organic iodine co-occur in groundwater at NCP with iodide as the dominant species. The geochemical modeling results indicate that groundwater fluoride is mainly associated with the saturation states of fluorite and calcite, as well as the adsorption equilibrium onto goethite and gibbsite, including the competitive adsorption between fluoride and carbonate. Groundwater iodine is mainly controlled by redox potential and pH condition of groundwater system. Reducing condition favors the mobilization and enrichment of groundwater iodide, which has the highest mobility among iodine species. Under reducing condition, reductive dissolution of iron (oxy)hydroxides is a potential geochemical process responsible for iodine release from sediment into groundwater. Under (sub)oxidizing condition, as groundwater pH over the 'point of zero charge' of iron (oxy)hydroxides, the lowering adsorption capacity of groundwater iodide/iodate on minerals leads to the release of sediment iodine into groundwater.
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Affiliation(s)
- Junxia Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; Laboratory of Basin Hydrology and Wetland Eco-restoration, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
| | - Hailing Zhou
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Kun Qian
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Xianjun Xie
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; Laboratory of Basin Hydrology and Wetland Eco-restoration, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Xiaobin Xue
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Yijun Yang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Yanxin Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China; School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
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Li J, Zhou H, Wang Y, Xie X, Qian K. Sorption and speciation of iodine in groundwater system: The roles of organic matter and organic-mineral complexes. JOURNAL OF CONTAMINANT HYDROLOGY 2017; 201:39-47. [PMID: 28495233 DOI: 10.1016/j.jconhyd.2017.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 04/06/2017] [Accepted: 04/23/2017] [Indexed: 06/07/2023]
Abstract
Characterizing the properties of main host of iodine in soil/sediment and the geochemical behaviors of iodine species are critical to understand the mechanisms of iodine mobilization in groundwater systems. Four surface soil and six subsurface sediment samples were collected from the iodine-affected area of Datong basin in northern China to conduct batch experiments and to evaluate the effects of NOM and/or organic-mineral complexes on iodide/iodate geochemical behaviors. The results showed that both iodine contents and kf-iodate values had positive correlations with solid TOC contents, implying the potential host of NOM for iodine in soil/sediment samples. The results of chemical removal of easily extracted NOM indicated that the NOM of surface soils is mainly composed of surface embedded organic matter, while sediment NOM mainly occurs in the form of organic-mineral complexes. After the removal of surface sorbed NOM, the decrease in kf-iodate value of treated surface soils indicates that surface sorbed NOM enhances iodate adsorption onto surface soil. By contrast, kf-iodate value increases in several H2O2-treated sediment samples, which was considered to result from exposed rod-like minerals rich in Fe/Al oxyhydroxide/oxides. After chemical removal of organic-mineral complexes, the lowest kf-iodate value for both treated surface soils and sediments suggests the dominant role of organic-mineral complexes on controlling the iodate geochemical behavior. In comparison with iodate, iodide exhibited lower affinities on all (un)treated soil/sediment samples. The understanding of different geochemical behaviors of iodine species helps to explain the occurrence of high iodine groundwater with iodate and iodide as the main species in shallow (oxidizing conditions) and deep (reducing conditions) groundwater.
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Affiliation(s)
- Junxia Li
- State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Hailing Zhou
- State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Yanxin Wang
- State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
| | - Xianjun Xie
- State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Kun Qian
- State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
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Zhao Y, Fu B, Wu T, Han X, Wang H, He C, Luo Y, Li K, Zhang K, Deng J. Transport of 125I in compacted GMZ bentonite containing Fe-oxides, Fe-minerals or Cu2O. J Radioanal Nucl Chem 2016. [DOI: 10.1007/s10967-015-4430-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Frasca B, Savoye S, Wittebroodt C, Leupin OX, Michelot JL. Comparative study of Se oxyanions retention on three argillaceous rocks: Upper Toarcian (Tournemire, France), Black Shales (Tournemire, France) and Opalinus Clay (Mont Terri, Switzerland). JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2014; 127:133-140. [PMID: 24215888 DOI: 10.1016/j.jenvrad.2013.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/13/2013] [Accepted: 10/04/2013] [Indexed: 06/02/2023]
Abstract
A comparative study of selenium oxyanion sorption was carried out by means of batch sorption experiments on three argillaceous rocks that differ in their mineralogical compositions and textural properties. The results show no selenate (Se(VI)) sorption onto the argillaceous rocks after 60 days, but clear sorption of selenite (Se(IV)), the extent being closely related to the initial Se(IV) concentration. At the lowest concentration ([Se(IV)]eq < 10(-8) mol L(-1)), the ranking of rock affinity for Se(IV) is Black Shales > Opalinus Clay (OPA) > Upper Toarcian, with Rd values of 910 ± 70, 600 ± 65 and 470 ± 70 mL g(-1) respectively. The Se(IV) sorption isotherms acquired for the three argillaceous rocks can be reproduced well by means of Langmuir formalism, particularly with a two-site Langmuir model. The comparison of the Se(IV) sorption isotherms obtained for these three rocks led to identification of pyrite associated with natural organic matter (NOM) as one of the main phases involved in selenium retention. While the desorption results suggested a significant Se(IV) reduction in the Upper Toarcian samples, the reversible sorption shown on the Black Shales and OPA samples was correlated with a sulfate increase, symptomatic of surface oxidation of pyrite which could limit the Se(IV) reduction in favor of sorption.
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Affiliation(s)
- B Frasca
- CEA, DEN/DANS/DPC/SECR/L3MR, F-91191 Gif-sur-Yvette, France; UMR "IDES" CNRS-Université de Paris-Sud, F-91405 Orsay, France.
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Savoye S, Frasca B, Grenut B, Fayette A. How mobile is iodide in the Callovo-Oxfordian claystones under experimental conditions close to the in situ ones? JOURNAL OF CONTAMINANT HYDROLOGY 2012; 142-143:82-92. [PMID: 23143184 DOI: 10.1016/j.jconhyd.2012.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 09/24/2012] [Accepted: 10/08/2012] [Indexed: 06/01/2023]
Abstract
The iodide behaviour towards the Callovo-Oxfordian claystone was studied using batch and diffusion experiments under conditions which limited the artefacts cited in the literature to be responsible for the iodide uptake (i.e. the experiments were carried out under anoxic conditions with N(2)/CO(2) atmosphere with a monitoring of the iodine redox-state). The results show that all the radioactive iodine was (125)I(-), with no measurable activity for (125)IO(3)(-), which is known to have a higher affinity for the rock than iodide. Moreover, the batch experiments revealed no sorption, independently of the initial iodide concentration (from 10(-6) to 10(-3) mol L(-1)) and the contact time (up to 106 days). Conversely, the diffusion experiments indicated a weak but measurable retention. The through-diffusion experiments led to distribution ratio values only significant (R(D)~0.05 mL g(-1)) for initial iodide concentration ≤ 10(-4) mol L(-1). Higher R(D) values were estimated from out-diffusion experiments, ranging from about 0.05 mL g(-1) for an initial concentration of 10(-3) mol L(-1) to 0.14 mL g(-1) for the lowest one. A retention phenomenon that could be reversible and kinetically-controlled was proposed to explain the differences in the extent of the iodide retardation of the two types of diffusion experiments.
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Affiliation(s)
- Sébastien Savoye
- CEA, DEN/DANS/DPC/SECR/Laboratoire de Mesures et Modélisation de la Migration des Radionucléides, F-91191 Gif-sur-Yvette, France.
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