Extraction of water and solutes from argillaceous rocks for geochemical characterisation: Methods, processes and current understanding

Sacchi, Elisa; Michelot, Jean‐Luc; Pitsch, H.; Lalieux, Philippe; Aranyossy, Jean-François

doi:10.1007/s100400000113

Cited by 83 publications

(56 citation statements)

References 57 publications

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“…Much effort has been made during recent years to improve the water extraction methods, develop numerical interpretation methods and achieve consistency of experimental data and geochemical modeling (Sacchi et al, 2001;Bradbury and Baeyens, 2003;Pearson et al, 2003;Fernández et al, 2004). Preserving in situ conditions of core samples is difficult.…”

Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

“…Preserving in situ conditions of core samples is difficult. A general discussion of perturbations caused by sampling, storage, preparation and extraction techniques is given by Sacchi et al (2001) and Pearson et al (2003). Aqueous extract tests (AET) have been used to obtain pore water chemistry for compacted FEBEX bentonite.…”

Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

“…Clay sample and water are stirred during a period of time of usually 2 days during which equilibration of water and clay sample is allowed. Chemical analyses are performed on the supernatant solution after phase separation by centrifugation (Sacchi et al, 2001). In addition to dilution, chemical reactions take place during pore water extraction which change the concentrations of dissolved species in a complex nonlinear manner.…”

Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

“…In addition to dilution, chemical reactions take place during pore water extraction which change the concentrations of dissolved species in a complex nonlinear manner. This makes it difficult to derive the chemical composition of the original pore water from the aqueous extract data (Bradbury and Baeyens, 1998;Sacchi et al, 2001). The inference of dissolved concentration for reactive species requires geochemical modeling based on mineralogical data (Bradbury and Baeyens, 1997, 2003Pearson et al, 2003;Fernández and Rivas, 2005;Zheng et al, 2008a).…”

Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

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A coupled THC model of the FEBEX in situ test with bentonite swelling and chemical and thermal osmosis

Zheng

Samper

Montenegro

2011

Journal of Contaminant Hydrology

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The performance assessment of a geological repository for radioactive waste requires quantifying the geochemical evolution of the bentonite engineered barrier. This barrier will be exposed to coupled thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes. This paper presents a coupled THC model of the FEBEX (Full-scale Engineered Barrier EXperiment) in situ test which accounts for bentonite swelling and chemical and thermal osmosis. Model results attest the relevance of thermal osmosis and bentonite swelling for the geochemical evolution of the bentonite barrier while chemical osmosis is found to be almost irrelevant. The model has been tested with data collected after the dismantling of heater 1 of the in situ test. The model reproduces reasonably well the measured temperature, relative humidity, water content and inferred geochemical data. However, it fails to mimic the solute concentrations at the heater-bentonite and bentonite-granite interfaces because the model does not account for the volume change of bentonite, the CO 2 (g) degassing and the transport of vapor from the bentonite into the granite. The inferred HCO 3 -and pH data cannot be explained solely by solute Page 2 of 54 transport, calcite dissolution and protonation/deprotonation by surface complexation, suggesting that such data may be affected also by other reactions.

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Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

Section: Inference Of Pore Water Composition From Aqueous Extract Datamentioning

confidence: 99%

See 2 more Smart Citations

A coupled THC model of the FEBEX in situ test with bentonite swelling and chemical and thermal osmosis

Zheng

Samper

Montenegro

2011

Journal of Contaminant Hydrology

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“…In order to obtain high-quality measurements of chloride (or any other tracer) in pore water of argillaceous rocks, many scientists have developed and improved various techniques [Sacchi et al, 2000[Sacchi et al, , 2001. One of the most recent is that developed by van der Kamp et al [1996] using direct chemical equilibration of the interstitial water through a liquid phase; this method was validated by comparing interstitial water concentrations calculated after equilibration with concentrations measured in ''free'' water collected by piezometers in the same formation.…”

Section: Introductionmentioning

confidence: 99%

Diffusion as the main process for mass transport in very low water content argillites: 1. Chloride as a natural tracer for mass transport—Diffusion coefficient and concentration measurements in interstitial water

Patriarche

Michelot

Ledoux

et al. 2004

Water Resources Research

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[1] Argillites are one of the rock types studied by French authorities for their confining properties for the isolation of radioactive wastes. One of the main objectives of such study is the better understanding of water transport through rocks with very low water content and hydraulic conductivity, using modeling of tracer profiles. This article presents the protocol developed and applied for acquiring data on chloride in interstitial water of the Toarcian argillites in Tournemire (southern France). This protocol is based on laboratory experiments involving diffusion process and on modeling. Experimental data obtained during transient and steady parts of diffusion allow for the assessment of the diffusion coefficient and initial concentration in pore water, respectively. Profiles for both have been acquired along the geological sequence; they are used in part 2 of this article for proposing a hydrogeological model where diffusion appears to be the main process for mass transport through the argillites and for comparing deuterium and chloride transport.

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Dynamic, structured heterogeneity of water isotopes inside hillslopes

Oshun

Dietrich

Dawson

et al. 2016

Water Resources Research

121

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Use of the stable isotopes of water (dD, d 18 O) to determine vegetative water sources, runoff paths, and residence times generally assumes that, other than shallow evaporative enrichment, the isotopic composition of precipitation is conserved as it travels through the subsurface to the stream channel. Here we follow rainfall through a thick (up to 25m) vadose zone of soil, saprolite, and weathered bedrock mostly composed of argillite, and underlying a steep (328) forested hillslope. We discover a persistent structured heterogeneity of water isotopes inside the hillslope. Summer dry season causes evaporative enrichment of the soil, but not in the saprolite and weathered bedrock. In winter, the mobile water, generated by successive rainstorms with widely varying isotopic composition, mixes in the vadose zone, elevating soil and rock moisture content, and eventually recharging the groundwater with isotopically invariant water similar to the seasonally averaged rainfall. Yet throughout the winter the less mobile winter soil and rock moisture remains relatively light, and water extracted from the interior of argillite lies well to the left of the local meteoric water line. This persistently light composition of soil and rock moisture and the deviation from average meteoric values suggest that subsurface fractionation, or the inheritance of paleo-meteoric rock moisture associated with rock uplift may lead to large enduring isotopic differences between high and low mobility water. These differences suggest that the use of water isotopes as tracers must consider the possibility of subsurface isotopic evolution and the influence of exchange with more tightly held water.

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Extraction of water and solutes from argillaceous rocks for geochemical characterisation: Methods, processes and current understanding

Cited by 83 publications

References 57 publications

A coupled THC model of the FEBEX in situ test with bentonite swelling and chemical and thermal osmosis

A coupled THC model of the FEBEX in situ test with bentonite swelling and chemical and thermal osmosis

Diffusion as the main process for mass transport in very low water content argillites: 1. Chloride as a natural tracer for mass transport—Diffusion coefficient and concentration measurements in interstitial water

Dynamic, structured heterogeneity of water isotopes inside hillslopes

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