HAL-BRGM, les publications scientifiques en libre accès du BRGM
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Dissipation of the insecticide profenofos in tropical agricultural soils (Berambadi catchment, South India): insight from compound-specific isotope analysis (CSIA)
No full textInternational audienceAssessing the role of agricultural lands in pesticide contamination of water ecosystems is critical for water management agencies and policymakers when formulating effective mitigation strategies. Current approaches based on concentration measurements are often insufficient to evaluate the contribution of pesticide dissipation processes in complex agroecosystems. This study focuses on the dissipation of profenofos insecticide within plots subject to intensive agriculture in the Berambadi watershed (India). We examined profenofos dissipation kinetics and related carbon isotopic fractionation in laboratory volatilisation, hydrolysis, photolysis and soil biodegradation experiments, and in a field plot experiment. Process-specific isotope fractionation analyses revealed significant carbon isotope fractionation, with epsilon(C) =- 2.0 f 0.8 %o during UV photolysis, and epsilon(C) =- 0.9 f 0.4 %o during biodegradation of profenofos in the soil. Accordingly, the formation of 4-bromo-2-chlorophenol and another profenofos transformation product indicated the cleavage of O-P and C-Br bonds in soil experiments. By integrating dissipation kinetics, compound-specific isotope analysis (CSIA), transformation products analysis and modelling results, biodegradation was identified as the dominant dissipation process in the agricultural plot, accounting for > 90 % of profenofos dissipation. Model predictions were consistent with the observed dissipation kinetics and isotopic data, confirming the fast degradation (T-1/2 = 1.1 +/- 0.6 day) and low (< 0.02 %) leaching potential of profenofos, which was not detected in the local groundwater monitored by passive samplers (POCIS). Overall, these results highlight the usefulness of profenofos CSIA to identify and unravel dissipation processes in tropical agroecosystems for improving contamination risk assessment
Effect of degassing on scaling in hypersaline system: Tuzla geothermal field, Turkey
No full textInternational audienceA serious issue with geothermal power plants is the loss of production and decline in power plant efficiency. Scaling, also known as mineral precipitation, is one of the frequently-observed issue that causes this loss and decreasing efficiency. It is heavily observed in the production wells when the geothermal fluid rises from the depths due to a change in the fluid's physical and chemical properties. Scaling issue in geothermal power plants result in significant output losses and lower plant effectiveness. In rare instances, it might even result in the power plant being shut down. The chemistry of the geothermal fluid, non-condensable gases, pH, temperature and pressure changes in the process from production to reinjection, power plant type and design, and sometimes the materials used can also play an active role in the scaling that will occur in a geothermal system. ICP-MS was used to evaluate the chemical properties of the fluids. On the other hand, XRD, XRF and SEM were used to investigate the chemical and mineralogical compositions of the scale samples in analytical methods. For the numerical approach, PhreeqC and GWELL codes were used to follow the chemical reactivity of the geothermal fluid in Tuzla production well. The novelty of this study is to determine potential degassing point and to characterize the mineralogical assemblage formed in the well because of the fluid composition, temperature and pressure variations. During production, geothermal fluids degas in the wellbore. This causes a drastic modification of the chemistry of the Tuzla fluids. This is why it is focused the calculations on the nature of the minerals that are able to precipitate inside the well. According to simulation results, the degassing point is estimated to be about 105 m depth, consistent with the field observations. If a small quantity of precipitated minerals is predicted before the boiling point, degassing significantly changes the fluid chemistry, and the model predicts the deposition of calcite along with smaller elements including galena, barite, and quartz. The simulation results are consistent with the mineral composition of scaling collected in the well
Regional assessment using public webcams of the role of post-storm recovery in the seasonal variability of beach width
No full textInternational audienceUnderstanding the mechanisms and times required for beaches to recover after extreme storms, as well as the effect of these episodic setbacks on long-term coastal erosion trends, is crucial for anticipating changes and implementing effective management strategies. A storm can have significant impacts on the coastline, resulting in retreats of several meters within hours. The natural recovery of the beach in the hours/days following a storm varies greatly between sites, ranging from a few days to several months. In this study, we examine the regional variability in coastal response during winter storms and post-storm recovery, using a beach width indicator obtained through the analysis of public webcam images on event, seasonal, and multi-year time scales. Video-derived shoreline positions were used to calculate weekly average beach widths at 11 sites along the coastline of Occitanie. The analysis demonstrated that storm responses and seasonal trends exhibit significant variability despite similarities in morphologies, and exposure to storm waves. Although post-storm recovery following the major events of 2021 and 2022 was nearly complete and very rapid for most sites, some beaches experienced prolonged recovery periods, requiring several months to return to their initial position. While the results indicated that storm events were sufficiently spaced to allow these beaches to recover, a series of events in autumn 2023 raises questions about this recovery capacity and underscores the potential impact of singular events on medium- and long-term coastal evolution trends
Exploring the Fabrication, Properties, and Morphology of Fluorine Substituted Hydroxyapatite Coatings
No full textInternational audienceHighlights▪ Atomic Force Microscopy (AFM) was used to analyze the surface topography of FHAp coatings and MG63 cell adhesion on FHAp coatings surface. ▪ FHAp coatings displayed uniform deposition with evenly distributed particle conglomerates. ▪ MG63 cells maintained normal morphology and adhered consistently to FHAp coatings over 72 hours. ▪ AFM imaging revealed a monolayer of well-aligned cells on FHAp coatings, suggesting good biocompatibility. ▪ FHAp coatings offer promising surfaces for MG63 cell adherence and proliferation.</div
Origin of Helium and Associated Fluid in Fault‐Related Hydrothermal Systems of the Eastern Pyrenees
No full textInternational audienceIntense hydrothermal activity hosted by regional tectonic structures occurs in the Eastern part of the Pyrenees. Helium isotope ratios (3He/4He) in hot springs along the Têt (0.033-0.099 Ra) and the Tech (0.171-0.375 Ra) faults indicate different signatures from purely crustal to slightly contaminated by magmatic helium. 3He/4He ratio increased towards the East, consistently with the observed thinning of the continental crust. These results suggest localised and not interconnected hydrothermal systems at fault scale. The origin of magmatic helium contamination is discussed in the light of the Gulf of Lion geodynamic evolution and data from comparable orogenic hydrothermal systems in the Alps
Future Circular Collider Feasibility Study Report Volume 1: Physics and Experiments
No full textInternational audienceVolume 1 of the FCC Feasibility Report presents an overview of the physics case, experimental programme, and detector concepts for the Future Circular Collider (FCC). This volume outlines how the FCC would address some of the most profound open questions in particle physics, from precision studies of the Higgs and EW bosons and of the top quark, to the exploration of physics beyond the Standard Model. The report reviews the experimental opportunities offered by the staged implementation of the FCC, beginning with an electron-positron collider (FCC-ee), operating at several centre-of-mass energies, followed by a hadron collider (FCC-hh). Benchmark examples are given of the expected physics performance, in terms of precision and sensitivity to new phenomena, of each collider stage. Detector requirements and conceptual designs for FCC-ee experiments are discussed, as are the specific demands that the physics programme imposes on the accelerator in the domains of the calibration of the collision energy, and the interface region between the accelerator and the detector. The report also highlights advances in detector, software and computing technologies, as well as the theoretical tools /reconstruction techniques that will enable the precision measurements and discovery potential of the FCC experimental programme. The content and structure of this report are guided by the scope and priorities defined in the mandate of the FCC Feasibility Study. It is therefore not intended to serve as an exhaustive review of the full physics potential of the FCC. Several topics, already covered in earlier reports such as the FCC CDR, are not reiterated here or are addressed only briefly, in alignment with the study’s focus. This volume reflects the outcome of a global collaborative effort involving hundreds of scientists and institutions, aided by a dedicated community-building coordination, and provides a targeted assessment of the scientific opportunities and experimental foundations of the FCC programme
3D Quantification of Subsidence During Pyrenean Retro‐Wedge Initiation: Role of Structural and Thermal Inheritance on Hyperextended Margin Inversion (Aquitaine Basin)
No full textInternational audienceWe present novel 3D subsidence data enabling vertical movements' quantification during the early formation of the Pyrenean retro-wedge. From Cenomanian to Turonian times, subsidence is relatively low (~26 ± 10 m/Myr), corresponding to a brief 10 Myr thermal re-equilibration of the European lithosphere following the hyperextended rift episode. The Coniacian-Santonian period marks a major subsidence reorganisation, with uplift or subsidence cessation on the former Early Cretaceous margin and a sudden acceleration in the necking domain (~300 ± 10 m/Myr). We interpret this episode as lithospheric buckling related to far-field deformation leading to superimposed flexural and thermal subsidence due to incomplete thermal re-equilibration. During Campanian-Maastrichtian time, subsidence decreases in the necking domain (~26 ± 10 m/Myr) and resumes on the margin (~26 ± 10 m/Myr), reflecting a homogenization of subsidence drivers across the Aquitaine Basin. This marks the progressive shift from post-rift thermal subsidence to flexural retro-foreland basin subsidence
Vers une modélisation semi-distribuée pour la simulation des étiages : comparaison de quatre modèles hydrologiques sur le bassin de la Meuse
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How are the data from the OZCAR RI critical zone observatories used by local stakeholders?
No full textInternational audienceThe long-term observatories of the OZCAR Critical Zone Research Infrastructure (https://www.ozcar-ri.org/ ) were initially set up to answer scientific questions of local interest to society. To answer these questions, a series of variables documenting meteorological conditions, hydro-geochemistry of surface water or aquifers, land surface fluxes and soils, as well as land use and practices are collected, sometimes over several decades. In the context of open science, these data are shared according to the FAIR (Findable, Accessible, Interoperable, Reusable) principles. However, a recurring question is the usefulness of making this data available and the use made of it by local stakeholders or citizens. To answer this question, observatory managers were asked to provide information on - The measured variables from their observatory used by local actors, - The stakeholders who use their data- The type of data used (raw data or data already transformed/digested by scientists) - The type of interactions they have with stakeholders.The results of the consultation show that the data is primarily used in universities or as part of initial training. Long-term involvement in the study-areas has also led to the establishment of long-lasting relationships with stakeholders (e.g. local authorities, hydropower companies, river basins management authorities, water agencies, Regional Natural Parks, state agencies (e.g. forest managers), associations, farmers and the public. Often, but not always, these stakeholders make direct use of the data produced by the observatories included in OZCAR RI. Qualified data from several monitored sites are used to manage the drinking water supply of several towns or municipalities, flood warning systems (in this case in near-real time or in a a posteriori analysis of problematic episodes), quantify water resources (quantity, quality), understand soil quality, or monitor wetland restoration. Nevertheless, in the face of increasingly strong and frequent pressures and disturbances, local stakeholders are increasingly questioning critical zone observatories to obtain data, trends and projections on the impact of climate change or land use. This information will help them to draw up regulatory documents and make decisions on the future habitability of their areas. Scientists are also called upon to provide scientific mediation and make the results of their research accessible to non-specialists. In addition to data, decision-makers, elected representatives and the public expect scientists to provide them with indicators that can be used more directly than raw data. In order to provide satisfactory responses to these new needs, it is necessary to co-construct the various actions, which requires time and a strong investment by scientists and stakeholders. As a result, new missions and new jobs are emerging, making observatories meeting places for local stakeholders and scientists. Observatories are becoming places, named Living Labs, where knowledge and research questions can be co-constructed, where citizens can be involved in metrology (participatory science), in order to better respond to the challenges of the Earth's habitability in the various areas
Approche microfluidique du transfert de masse aux interfaces fluide-fluide dans les milieux poreux avec contrôle de mouillabilité par plasma et analyse par spectroscopie Raman
No full textThis PhD thesis is part of the INTER-AQ project within CNRS, an interdisciplinary research initiative aiming to unravel the complex and coupled dynamics of mass transfer and fluid redistribution at fluid-fluid interfaces within porous media. The project combines experimental microfluidics to replicate subsurface environments, vibrational spectroscopy for in situ chemical quantification, and novel plasma-based techniques to tailor pore surface properties. These integrated approaches target key environmental and energy challenges, such as geological CO₂ storage. Within this framework, the PhD research contributes to a pore-scale perspective, advancing experimental methods to investigate how interfacial phenomena influence fluid behavior in porous systems. The objective of this thesis is to address a fundamental gap in our understanding of mass transfer at the pore scale, specifically how wettability affects fluid/fluid interfacial mass transfer processes and fluid trapping in geological porous media. The research focuses on the development of an experimental platform that integrates microfluidics and μRaman spectroscopy to track CO₂-water interfacial mass transfer in real time. Microfluidic devices are transparent pore networks made of channels of rectangular cross-sections, mimicking subsurface porous environments and allowing direct visualization of fluid behaviors. Crucially, the study introduces in situ atmospheric pressure plasma treatment as a new tool for modifying wettability within closed glass microfluidic devices. This allows precise control over surface characteristics, enabling systematic investigation of wettability impacts on interfacial dynamics. The insights of wettability influenced interfacial mass transfer gained in this study are expected to improve the calibration of both pore- and field-scale models, increasing the accuracy of predictions for carbon storage in geological reservoirs. Three core research questions structure the investigation. First, the feasibility of propagating atmospheric plasma within closed microfluidic channels is explored to determine whether in situ wettability tuning is technically viable. The work demonstrates that plasma jets can be successfully introduced and controlled within the devices, enabling reliable alteration of surface wettability. Results obtained by in situ contact angle measurement on images indicate uniform wettability treatment with increased hydrophilic properties after only 1 min of plasma treatment. The wettability achieved on glass with our setup offers stability for up to 70 days, depending on the plasma treatment and storage parameters. Second, the study examines how wettability conditions affect capillary trapping and interfacial mass transfer. By employing microfluidic devices with increasing geometrical complexity, the experiments reveal how surface wettability indeed influences fluid displacement/ retention, water evaporation and CO₂ dissolution under a range of flow conditions. Our results demonstrate the influence of wettability on fluid-fluid displacement and mass transfer processes. Third, the potential of μRaman spectroscopy for in situ, semi-quantitative analysis of CO₂ dissolution is assessed. Raman analyses is able to capture the temporal evolution of dissolved species, providing complementary chemical data to visual flow observations and enabling the quantification of interfacial mass transfer rates. In summary, this research establishes an integrated atmospheric-plasma-microfluidic-μRaman experimental framework that allows for the systematic study of pore-scale interfacial mass transfer under controlled wettability conditions. By leveraging plasma technology for surface modification and spectroscopic techniques for chemical analysis on microfluidic devices, the thesis delivers new insights into the mechanisms that govern CO₂ trapping in porous media and that are critical for the design and optimization of carbon sequestration strategies.Cette thèse de doctorat s’inscrit dans le cadre du projet INTER-AQ porté par le CNRS, une initiative de recherche interdisciplinaire visant à élucider les dynamiques complexes et couplées du transfert de masse et de la redistribution des fluides aux interfaces fluide-fluide dans les milieux poreux. Le projet combine la microfluidique expérimentale pour reproduire des environnements souterrains, la spectroscopie Raman pour la quantification chimique in situ, et des techniques innovantes à base de plasma pour moduler les propriétés de surface des pores. Ces approches intégrées ciblent des enjeux énergétiques majeurs, tels que le stockage géologique du CO₂. Dans ce cadre, la recherche doctorale apporte une contribution à l’échelle des pores, en développant des méthodes expérimentales permettant d’analyser comment les phénomènes interfaciaux influencent le comportement des fluides dans les systèmes poreux. Cette thèse vise à combler une lacune essentielle dans la compréhension du transfert de masse à l’échelle des pores, en s’intéressant spécifiquement à l’impact de la mouillabilité sur les échanges aux interfaces fluide–fluide et sur les mécanismes de piégeage. Cette étude présente le développement d’une plateforme expérimentale intégrant la microfluidique et la spectroscopie μRaman. Les dispositifs microfluidiques sont des réseaux de pores transparents constitués de canaux, simulant des environnements poreux souterrains et permettant une visualisation directe des comportements des fluides. Cette étude propose, pour la première fois, l’utilisation in situ du traitement plasma à pression atmosphérique comme outil de contrôle de la mouillabilité. Les connaissances acquises sur le transfert de masse interfacial en fonction des propriétés de mouillabilité devraient permettre d’améliorer l’étalonnage des modèles numériques à l’échelle des pores comme à l’échelle du réservoir, augmentant ainsi la précision des prévisions pour le stockage du carbone dans les réservoirs géologiques. L’étude s’articule autour de trois questions de recherche principales. Premièrement, la faisabilité de la propagation d’un plasma atmosphérique dans des canaux microfluidiques fermés est examinée pour contrôler la mouillabilité des surfaces. Le travail démontre qu’un jet de plasma à pression atmosphérique peut être introduit et contrôlé avec succès dans les dispositifs, permettant une modification fiable de la mouillabilité des canaux. Les résultats obtenus par mesure in situ de l’angle de contact sur images indiquent un traitement homogène avec un accroissement des propriétés hydrophiles. La mouillabilité obtenue sur le verre avec notre configuration montre une stabilité pouvant atteindre 70 jours, selon les paramètres de traitement plasma et de stockage. Deuxièmement, l’étude examine comment les conditions de mouillabilité affectent le piégeage capillaire et le transfert de masse interfacial. En utilisant des dispositifs microfluidiques de complexité géométrique croissante, les expériences révèlent que la mouillabilité de surface influence effectivement le piégeage résiduel, l’évaporation de l’eau et la dissolution du CO₂ sous différentes conditions d’écoulement. Troisièmement, le potentiel de la spectroscopie μRaman pour une analyse in situ semi-quantitative de la dissolution du CO₂ est évalué. L’analyse Raman permet de capturer l’évolution temporelle des espèces dissoutes, fournissant des données chimiques complémentaires aux observations visuelles des écoulements, et permettant la quantification des taux de transfert de masse interfaciale. En résumé, cette recherche intègre les plasmas atmosphériques, la microfluidique et la spectroscopie μRaman, pour l’étude du transfert de masse à l’échelle des pores sous conditions de mouillabilité contrôlées. La thèse apporte de nouvelles connaissances sur les mécanismes régissant le piégeage du CO₂ dans les milieux poreux, essentiels à la conception et à l’optimisation des stratégies de séquestration du carbone