258 research outputs found
GDAT intercomparison exercice on CFCs and SF6 tracers for groundwater dating
No full textInternational audienceGDAT intercomparison exercice on CFCs and SF6 tracers for groundwater dating Labasque T. Géosciences Rennes, Université Rennes1-CNRS, Rennes, France GDAT-participants for CFCs and SF6 comparisons: Aquilina L., Vergnaud V., Geosciences Rennes, France; Goody D., BGS Wallingford, UK; Leaney F., Suckow A., CSIRO, Australia; Oster H, Spurentofflabor, Germany; Han L., Hillegonds D, Matsumoto T., IAEA, Austria; Aeschbach-Hertig W., Freund F., Schneider T., Heidelberg, Germany; Yoon Y., Kigam, Corea; Busenberg E., Casile J., USGS Reston Lab, USA; Rosanski K., Bartysel J., AGH, Poland; Sliwka I., Bielewski J., INP, Poland; Rigby A., Solomon K;, University of Utah, USA; Barbecot F., IDES, France. Two intercomparison exercises have been carried out in 2012 by the hydrogeochemist community : Fontainebleau sandy aquifer (January 2012) and Betton fractured shists aquifer (October 2012). Environmental tracers devoted to groundwater dating were compared during these experiments. These methods are very sensitive and need a great analytical practice to obtain accurate results. The GDAT exercise was designed in order to compare methods and analytical protocols. All the participants sampled groundwater from the same boreholes at the same time using similar sampling methods, and analysed similar environmental tracers using for each laboratory its own analytical protocol. We here present CFCs and SF6 results obtained on the Fontainebleau aquifer and on the Betton aquifer. The first one shows quite "old" CFC waters and the second one "younger" CFCs waters. The intercomparison exercise brought together 31 laboratories from 14 countries including 12 laboratories for CFCs analysis and 11 for SF6 analysis. Results show good agreement for most of the laboratories with apparent uncertainties less than 3 years on the quite "old" CFCs waters. The major uncertainty source results from sampling and storage methods
GDAT intercomparison exercice on CFCs and SF6 tracers for groundwater dating
No full textInternational audienceGDAT intercomparison exercice on CFCs and SF6 tracers for groundwater dating Labasque T. Géosciences Rennes, Université Rennes1-CNRS, Rennes, France GDAT-participants for CFCs and SF6 comparisons: Aquilina L., Vergnaud V., Geosciences Rennes, France; Goody D., BGS Wallingford, UK; Leaney F., Suckow A., CSIRO, Australia; Oster H, Spurentofflabor, Germany; Han L., Hillegonds D, Matsumoto T., IAEA, Austria; Aeschbach-Hertig W., Freund F., Schneider T., Heidelberg, Germany; Yoon Y., Kigam, Corea; Busenberg E., Casile J., USGS Reston Lab, USA; Rosanski K., Bartysel J., AGH, Poland; Sliwka I., Bielewski J., INP, Poland; Rigby A., Solomon K;, University of Utah, USA; Barbecot F., IDES, France. Two intercomparison exercises have been carried out in 2012 by the hydrogeochemist community : Fontainebleau sandy aquifer (January 2012) and Betton fractured shists aquifer (October 2012). Environmental tracers devoted to groundwater dating were compared during these experiments. These methods are very sensitive and need a great analytical practice to obtain accurate results. The GDAT exercise was designed in order to compare methods and analytical protocols. All the participants sampled groundwater from the same boreholes at the same time using similar sampling methods, and analysed similar environmental tracers using for each laboratory its own analytical protocol. We here present CFCs and SF6 results obtained on the Fontainebleau aquifer and on the Betton aquifer. The first one shows quite "old" CFC waters and the second one "younger" CFCs waters. The intercomparison exercise brought together 31 laboratories from 14 countries including 12 laboratories for CFCs analysis and 11 for SF6 analysis. Results show good agreement for most of the laboratories with apparent uncertainties less than 3 years on the quite "old" CFCs waters. The major uncertainty source results from sampling and storage methods
A glimpse of the Anthropocene captured by environmental tracers in the groundwater of a fractured aquifer
No full textInternational audienceGoldschmidt 2021 Abstracthttps://doi.org/10.7185/gold2021.6897A glimpse of the Anthropocenecaptured by environmental tracers inthe groundwater of a fracturedaquiferDR. ELIOT CHATTON1, THIERRY LABASQUE2,WERNER AESCHBACH3, VIRGINIE VERGNAUD2 ANDLUC AQUILINA41CNRS UMR61182Univ. Rennes, CNRS, UMS 33433Institute of Environmental Physics4Université de Rennes 1 Géosciences Rennes UMR 6118Presenting Author: [email protected] Anthropocene is an epoch in Earth’s history that has beenproposed to characterise the global impact of human activities onthe Earth's atmosphere, biosphere, hydrosphere, geosphere, i.e.the Critical Zone.Just as for past climates, the signature of these anthropogenicimpacts are recorded by environmental tracers dissolved ingroundwater that could provide a better understanding ofgroundwater flows, residence time and mixing thus providinginformation on this major water resource both in terms ofquantity and quality.In this study, we use dissolved gases (CFCs, SF6, 4He, 14C,noble gases, VOCs, stable isotopes) and groundwater chemicalcomposition as environmental tracers to unveil insights of theAnthropocene in a fractured aquifer in the northwest of France.We analyse the impact of groundwater abstraction on residencetime and excess air composition. We evidence the influence ofclimate change on groundwater recharge temperature (noble gastemperatures, NGT). We also quantify the appearance ofanthropogenic compounds over the last decades.These observations enable us to define the Anthropocenesignature in groundwater and the distribution of its impacts onthe groundwater resource in order to gain a better picture of itsresilience in the future
Quantification of conservative and reactive transport using a singlegroundwater tracer test in a fractured media
No full textInternational audiencedentification of biogeochemical reactions in aquifers and determining kinetics is important for the predictionof contaminant transport in aquifers and groundwater management. Therefore, experiments accounting for bothconservative and reactive transport are essential to understand the biogeochemical reactivity at field scale.This study presents the results of a groundwater tracer test using the combined injection of dissolved conservativeand reactive tracers (He, Xe, Ar, Br-, O2and NO3-) in order to evaluate the transport properties of a fracturedmedia in Brittany, France.Dissolved gas concentrations were continuously monitored in situ with a CF-MIMS (Chatton et al, 2016) allowinga high frequency (1 gas every 2 seconds) multi-tracer analysis (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe)over a large resolution (6 orders of magnitude). Along with dissolved gases, groundwater biogeochemistry wasmonitored through the sampling of major anions and cations, trace elements and microbiological diversity.The results show breakthrough curves allowing the combined quantification of conservative and reactive transportproperties. This ongoing work is an original approach investigating the link between heterogeneity of porousmedia and biogeochemical reactions at field scale.Eliot Chatton, Thierry Labasque, Je ́roˆme de La Bernardie, Nicolas Guihe ́neuf, Olivier Bour and LucAquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics andBiogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016
Quantification of conservative and reactive transport using a singlegroundwater tracer test in a fractured media
No full textInternational audiencedentification of biogeochemical reactions in aquifers and determining kinetics is important for the predictionof contaminant transport in aquifers and groundwater management. Therefore, experiments accounting for bothconservative and reactive transport are essential to understand the biogeochemical reactivity at field scale.This study presents the results of a groundwater tracer test using the combined injection of dissolved conservativeand reactive tracers (He, Xe, Ar, Br-, O2and NO3-) in order to evaluate the transport properties of a fracturedmedia in Brittany, France.Dissolved gas concentrations were continuously monitored in situ with a CF-MIMS (Chatton et al, 2016) allowinga high frequency (1 gas every 2 seconds) multi-tracer analysis (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe)over a large resolution (6 orders of magnitude). Along with dissolved gases, groundwater biogeochemistry wasmonitored through the sampling of major anions and cations, trace elements and microbiological diversity.The results show breakthrough curves allowing the combined quantification of conservative and reactive transportproperties. This ongoing work is an original approach investigating the link between heterogeneity of porousmedia and biogeochemical reactions at field scale.Eliot Chatton, Thierry Labasque, Je ́roˆme de La Bernardie, Nicolas Guihe ́neuf, Olivier Bour and LucAquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics andBiogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016
Quantification of conservative and reactive transport using a singlegroundwater tracer test in a fractured media
No full textInternational audiencedentification of biogeochemical reactions in aquifers and determining kinetics is important for the predictionof contaminant transport in aquifers and groundwater management. Therefore, experiments accounting for bothconservative and reactive transport are essential to understand the biogeochemical reactivity at field scale.This study presents the results of a groundwater tracer test using the combined injection of dissolved conservativeand reactive tracers (He, Xe, Ar, Br-, O2and NO3-) in order to evaluate the transport properties of a fracturedmedia in Brittany, France.Dissolved gas concentrations were continuously monitored in situ with a CF-MIMS (Chatton et al, 2016) allowinga high frequency (1 gas every 2 seconds) multi-tracer analysis (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe)over a large resolution (6 orders of magnitude). Along with dissolved gases, groundwater biogeochemistry wasmonitored through the sampling of major anions and cations, trace elements and microbiological diversity.The results show breakthrough curves allowing the combined quantification of conservative and reactive transportproperties. This ongoing work is an original approach investigating the link between heterogeneity of porousmedia and biogeochemical reactions at field scale.Eliot Chatton, Thierry Labasque, Je ́roˆme de La Bernardie, Nicolas Guihe ́neuf, Olivier Bour and LucAquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics andBiogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016
Towards operational hydrology for a thorough spatio-temporalexploration of the Critical Zone
No full textInternational audienceOver the last century, the Critical Zone faced remarkable climate and land use changes increasing the pressures onthe Hydrosphere and giving rise to numerous environmental consequences in terms of water quantity and quality.From now on, the Critical Zone must face the challenge to supply 9 billion people with quality food and safedrinking water in a context of global warming. For the Hydrosphere, this challenge could be addressed with abetter understanding of the dynamics and resilience of aquatic environments (rivers, lakes, groundwaters, oceans).In view of the spatial and temporal variety and variability of flow dynamics and biogeochemical reactions occur-ring in the Hydrosphere a new investigation method is needed. This study approaches the concept of “operationalhydrology” aiming to enhance either the spatio-temporal distribution and the quality of environmental data for athorough exploration of the Hydrosphere.To illustrate our approach, we present natural and anthropogenic dissolved gas data (He, Ne, Ar, Kr, Xe, N2, O2,CO2, CH4, N2O, H2, BTEX, and some VOCs) measured in situ with a CF-MIMS (Chatton et al, 2016) installedin a mobile laboratory arranged in an all-terrain truck (CRITEX-Lab). This ongoing work focuses on groundwaterand the field investigation of residence time distributions, recharge processes (origins), water flow paths andmixing, biogeochemical reactivity and contamination (sources).The rationale behind “operational hydrology” could be applied to the field measurement at high-frequency ofmany other environmental parameters (temperature, cations, anions, isotopes, micro-organisms) not only for theinvestigation of groundwaters but also rivers, lakes and oceans.Eliot Chatton, Thierry Labasque, Jerome de La Bernardie, Nicolas Guihe neuf, Olivier Bour and LucAquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics andBiogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016
Apports des traceurs environnementaux à la connaissance de l’âge des eaux souterraines
No full textEnvironmental tracers are relevant tools for understanding the water cycle and particularly for understanding the circulation of groundwater. Groundwater is indeed invisible to humans most of the time and circulates in complex and heterogeneous geological environments. This resource suffers from serious anthropogenic impacts due to its overexploitation, especially in arid regions. It also undergoes a degradation of its chemical, even bacteriological quality by the use in particular of pollutants on the surface of the ground. Water stocks, their evolution and their vulnerability must therefore be estimated. Understanding of the groundwater cycle is accessible, in particular through the use of chemical compounds such as environmental tracers, which will integrate the water molecule, or dissolve in water and follow it along it course in the rocks. Knowledge of the origin of these tracers in water and their evolution, coupled with high-performance analytical techniques, should make it possible to reconstruct the history of these waters, in terms of residence time, mixtures, and geographical origin. The water age ranges estimated by these tracers go from a few days to several million years and therefore cover almost all of the water ages in the ground. Analytical techniques have progressed considerably from the second half of the 20th century, to allow these tracers to be measured at extremely low concentrations, with increasingly reduced volumes of water, thus allowing their democratization in the world scientific community. The interpretation models for these tracers have also been greatly developed in order to better consider the advective, dispersive and diffusive processes of water and associated tracers.Les traceurs environnementaux sont des outils pertinents pour la compréhension du cycle de l’eau et particulièrement pour la compréhension de la circulation de l’eau souterraine. L’eau souterraine est en effet invisible à l’homme la plupart du temps et circule dans des milieux géologiques complexes et hétérogènes. Cette ressource subit de graves impacts anthropiques de par sa surexploitation, notamment dans les régions arides. Elle subit également une dégradation de sa qualité chimique, voire bactériologique, par l’utilisation notamment de polluants à la surface du sol. Les stocks d’eau, leur évolution et leur vulnérabilité doivent donc être estimés. La compréhension du cycle de l’eau souterraine est accessible, notamment par l’utilisation de composés chimiques tels que les traceurs environnementaux, qui vont intégrer la molécule d’eau, ou se dissoudre dans l’eau et suivre celle-ci le long de son parcours dans les roches. Une connaissance de l’origine de ces traceurs dans l’eau et de leur évolution, couplée à des techniques analytiques performantes, doivent permettre de reconstituer l’histoire de ces eaux, en termes de temps de résidence, de mélanges, et d’origine géographique. Les gammes d’âges de l’eau estimées par ces traceurs vont de quelques jours à plusieurs millions d’années et couvrent donc la quasi-totalité des eaux présentes dans le sous-sol. Les techniques analytiques ont beaucoup progressé à partir de la seconde moitié du XXeme siècle, pour permettre de mesurer ces traceurs à des concentrations extrêmement faibles, avec des volumes d’eau de plus en plus réduits, permettant ainsi leur démocratisation dans la communauté scientifique mondiale. Les modèles d’interprétation de ces traceurs se sont également beaucoup développés afin de mieux prendre en compte les processus advectifs, dispersifs et diffusifs de l’eau et des traceurs associés
Contribution of environmental tracers to knowledge of the age of groundwater
No full textLes traceurs environnementaux sont des outils pertinents pour la compréhension du cycle de l’eau et particulièrement pour la compréhension de la circulation de l’eau souterraine. L’eau souterraine est en effet invisible à l’homme la plupart du temps et circule dans des milieux géologiques complexes et hétérogènes. Cette ressource subit de graves impacts anthropiques de par sa surexploitation, notamment dans les régions arides. Elle subit également une dégradation de sa qualité chimique, voire bactériologique, par l’utilisation notamment de polluants à la surface du sol. Les stocks d’eau, leur évolution et leur vulnérabilité doivent donc être estimés. La compréhension du cycle de l’eau souterraine est accessible, notamment par l’utilisation de composés chimiques tels que les traceurs environnementaux, qui vont intégrer la molécule d’eau, ou se dissoudre dans l’eau et suivre celle-ci le long de son parcours dans les roches. Une connaissance de l’origine de ces traceurs dans l’eau et de leur évolution, couplée à des techniques analytiques performantes, doivent permettre de reconstituer l’histoire de ces eaux, en termes de temps de résidence, de mélanges, et d’origine géographique. Les gammes d’âges de l’eau estimées par ces traceurs vont de quelques jours à plusieurs millions d’années et couvrent donc la quasi-totalité des eaux présentes dans le sous-sol. Les techniques analytiques ont beaucoup progressé à partir de la seconde moitié du XXeme siècle, pour permettre de mesurer ces traceurs à des concentrations extrêmement faibles, avec des volumes d’eau de plus en plus réduits, permettant ainsi leur démocratisation dans la communauté scientifique mondiale. Les modèles d’interprétation de ces traceurs se sont également beaucoup développés afin de mieux prendre en compte les processus advectifs, dispersifs et diffusifs de l’eau et des traceurs associés.Environmental tracers are relevant tools for understanding the water cycle and particularly for understanding the circulation of groundwater. Groundwater is indeed invisible to humans most of the time and circulates in complex and heterogeneous geological environments. This resource suffers from serious anthropogenic impacts due to its overexploitation, especially in arid regions. It also undergoes a degradation of its chemical, even bacteriological quality by the use in particular of pollutants on the surface of the ground. Water stocks, their evolution and their vulnerability must therefore be estimated. Understanding of the groundwater cycle is accessible, in particular through the use of chemical compounds such as environmental tracers, which will integrate the water molecule, or dissolve in water and follow it along it course in the rocks. Knowledge of the origin of these tracers in water and their evolution, coupled with high-performance analytical techniques, should make it possible to reconstruct the history of these waters, in terms of residence time, mixtures, and geographical origin. The water age ranges estimated by these tracers go from a few days to several million years and therefore cover almost all of the water ages in the ground. Analytical techniques have progressed considerably from the second half of the 20th century, to allow these tracers to be measured at extremely low concentrations, with increasingly reduced volumes of water, thus allowing their democratization in the world scientific community. The interpretation models for these tracers have also been greatly developed in order to better consider the advective, dispersive and diffusive processes of water and associated tracers
Continuous monitoring of dissolved gases with membrane inlet massspectrometry to fingerprint river biochemical activity
No full textInternational audienceWater quality in rivers results from biogeochemical processes in contributing hydrological compartments (soils,aquifers, hyporheic and riparian zones) and biochemical activity in the river network itself. Consequently,chemical fluxes fluctuate on multiple spatial and temporal scales, leading eventually to complex concentrationsignals in rivers. We characterized these fluctuations with innovative continuous monitoring of dissolved gases, toquantify transport and reaction processes occurring in different hydrological compartments.We performed stream-scale experiments in two headwater streams in Brittany, France. Factorial injections ofinorganic nitrogen (NH4NO3), inorganic phosphate (P2O5) and multiple sources of labile carbon (acetate,tryptophan) were implemented in the two streams. We used a new field application of membrane inlet massspectrometry to continuously monitor dissolved gases for multiple day-night periods (Chatton et al., 2016).Quantified gases included He, O2, N2, CO2, CH4, N2O, and 15N of dissolved N2 and N2O. We calibrated andassessed the methodology with well-established complementary techniques including gas chromatography andhigh-frequency water quality sensors. Wet chemistry and radon analysis complemented the study.The analyses provided several methodological and ecological insights and demonstrated that high frequencyvariations linked to background noise can be efficiently determined and filtered to derive effective fluxes. Froma more fundamental point of view, the tested stream segments were fully characterized with extensive samplingof riverbeds and laboratory experiments, allowing scaling of point-level microbial and invertebrate diversity andactivity on in-stream processing. This innovative technology allows fully-controlled in-situ experiments providingrich information with a high signal to noise ratio. We present the integrated nutrient demand and uptake anddiscuss limiting processes and elements at the reach and catchment scales.Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour, Luc Aquilina.2016. Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics andBiogeochemistry of Groundwater Flow. Environ. Sci. Technol
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