Boom Clay pore water geochemistry at the Mol site: Experimental data as determined by in situ sampling of the piezometers

Research output: Contribution to journalArticlepeer-review

Bibtex - Download

@article{7385b7b78e91490bb28d519dfc456749,
title = "Boom Clay pore water geochemistry at the Mol site: Experimental data as determined by in situ sampling of the piezometers",
abstract = "In many countries, geological disposal in clay is the primary option for the final disposal of high-level radioactive waste and spent fuel. In Belgium, the Boom Clay is studied as a potential host rock for the disposal of radioactive waste. In this frame, the pore water geochemistry of the Boom Clay is an essential feature for evaluating the performance and long term safety of geological disposal in a host rock because: (1) it determines the speciation and solubility of radionuclides, and (2) it is required as initial or boundary condition to evaluate the interactions with other repository components, i.e. the different waste forms and the engineered barrier system (e.g. overpack materials, backfill), as well as to evaluate the influence of the repository construction (e.g. oxidation, interaction with the liner if present). In this study, we report a unique, first of its kind data set of the in situ sampled pore waters of the Boom Clay at the Mol site, covering a depth interval of 65 m. The thorough screening of the collected data for potential geochemical perturbations and sampling artifacts led to a reference data set of 195 pore waters complemented with 39 in situ gas and pH analyses. A statistical analysis was applied to this dataset and a reference pore water composition was derived for the Boom Clay pore water at the Mol site. The reported ranges of the elemental concentrations reflect pore water natural variations at formation scale, whereas in situ sampled pCO2 and pH values are limited to the depth interval enveloped by HADES URL at 196–200 m below sea level. Thus, uncertainty remains on the variations of the pCO2 and pH at the scale of Boom Clay Formation. The reference pore water chemistry dataset will help to update current geochemical pore water chemistry model. At the same time, the presented data set can improve geochemical modelling strategies developed for low permeability sediments, like argillites and shales, where direct pore water sampling is technically difficult.",
keywords = "Boom Clay, Pore water extraction, Chemical analyses, pH, Alkalinity, pCO2, Redox potential, Reference pore water composition",
author = "Miroslav Honty and Lander Frederickx and Lian Wang and {De Craen}, Mieke and Peter Thomas and Hugo Moors and Elke Jacops",
note = "Score=10",
year = "2022",
month = jan,
day = "1",
doi = "https://doi.org/10.1016/j.apgeochem.2021.105156",
language = "English",
volume = "136",
pages = "1--19",
journal = "Applied Geochemistry",
issn = "0883-2927",
publisher = "Elsevier",

}

RIS - Download

TY - JOUR

T1 - Boom Clay pore water geochemistry at the Mol site: Experimental data as determined by in situ sampling of the piezometers

AU - Honty, Miroslav

AU - Frederickx, Lander

AU - Wang, Lian

AU - De Craen, Mieke

AU - Thomas, Peter

AU - Moors, Hugo

AU - Jacops, Elke

N1 - Score=10

PY - 2022/1/1

Y1 - 2022/1/1

N2 - In many countries, geological disposal in clay is the primary option for the final disposal of high-level radioactive waste and spent fuel. In Belgium, the Boom Clay is studied as a potential host rock for the disposal of radioactive waste. In this frame, the pore water geochemistry of the Boom Clay is an essential feature for evaluating the performance and long term safety of geological disposal in a host rock because: (1) it determines the speciation and solubility of radionuclides, and (2) it is required as initial or boundary condition to evaluate the interactions with other repository components, i.e. the different waste forms and the engineered barrier system (e.g. overpack materials, backfill), as well as to evaluate the influence of the repository construction (e.g. oxidation, interaction with the liner if present). In this study, we report a unique, first of its kind data set of the in situ sampled pore waters of the Boom Clay at the Mol site, covering a depth interval of 65 m. The thorough screening of the collected data for potential geochemical perturbations and sampling artifacts led to a reference data set of 195 pore waters complemented with 39 in situ gas and pH analyses. A statistical analysis was applied to this dataset and a reference pore water composition was derived for the Boom Clay pore water at the Mol site. The reported ranges of the elemental concentrations reflect pore water natural variations at formation scale, whereas in situ sampled pCO2 and pH values are limited to the depth interval enveloped by HADES URL at 196–200 m below sea level. Thus, uncertainty remains on the variations of the pCO2 and pH at the scale of Boom Clay Formation. The reference pore water chemistry dataset will help to update current geochemical pore water chemistry model. At the same time, the presented data set can improve geochemical modelling strategies developed for low permeability sediments, like argillites and shales, where direct pore water sampling is technically difficult.

AB - In many countries, geological disposal in clay is the primary option for the final disposal of high-level radioactive waste and spent fuel. In Belgium, the Boom Clay is studied as a potential host rock for the disposal of radioactive waste. In this frame, the pore water geochemistry of the Boom Clay is an essential feature for evaluating the performance and long term safety of geological disposal in a host rock because: (1) it determines the speciation and solubility of radionuclides, and (2) it is required as initial or boundary condition to evaluate the interactions with other repository components, i.e. the different waste forms and the engineered barrier system (e.g. overpack materials, backfill), as well as to evaluate the influence of the repository construction (e.g. oxidation, interaction with the liner if present). In this study, we report a unique, first of its kind data set of the in situ sampled pore waters of the Boom Clay at the Mol site, covering a depth interval of 65 m. The thorough screening of the collected data for potential geochemical perturbations and sampling artifacts led to a reference data set of 195 pore waters complemented with 39 in situ gas and pH analyses. A statistical analysis was applied to this dataset and a reference pore water composition was derived for the Boom Clay pore water at the Mol site. The reported ranges of the elemental concentrations reflect pore water natural variations at formation scale, whereas in situ sampled pCO2 and pH values are limited to the depth interval enveloped by HADES URL at 196–200 m below sea level. Thus, uncertainty remains on the variations of the pCO2 and pH at the scale of Boom Clay Formation. The reference pore water chemistry dataset will help to update current geochemical pore water chemistry model. At the same time, the presented data set can improve geochemical modelling strategies developed for low permeability sediments, like argillites and shales, where direct pore water sampling is technically difficult.

KW - Boom Clay

KW - Pore water extraction

KW - Chemical analyses

KW - pH

KW - Alkalinity

KW - pCO2

KW - Redox potential

KW - Reference pore water composition

UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/47108891

U2 - https://doi.org/10.1016/j.apgeochem.2021.105156

DO - https://doi.org/10.1016/j.apgeochem.2021.105156

M3 - Article

VL - 136

SP - 1

EP - 19

JO - Applied Geochemistry

JF - Applied Geochemistry

SN - 0883-2927

M1 - 105156

ER -

ID: 7310726