HAL-BRGM, les publications scientifiques en libre accès du BRGM
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Innovations pour une gestion concertée et durable de l'eau
No full textLa gestion de l’eau est devenue un enjeu majeur du fait de la pression anthropique croissante et du changement climatique. Elle constitue un domaine particulier d’innovations car l’eau est un bien commun qui circule. L’eau est nécessaire à la vie et à tous les secteurs économiques, et dont la gestion combine des dimensions technologiques, organisationnelles, institutionnelles et sociales. Ce numéro d’Innovations. Revue d’économie et de management de l’innovation précise les enjeux actuels des innovations pour la gestion de l’eau, à travers des articles de synthèse et l’analyse de situations variées : la construction d’une tarification de l’eau ; des innovations low cost ; l’intégration de la télédétection pour gérer la ressource des fleuves ; la valorisation des eaux usées ; les services « Eau, Assainissement, Hygiène » dans les villes africaines… Ces travaux associent « Water Studies » et « Innovation Studies ». Ils mettent aussi en débat les approches jusque-là trop centrées sur les innovations techniques, appelant à développer une vision plus systémique et circulaire, mais aussi responsable et participative
Biodiversity co-variation patterns in a range of soil organism taxa across highly contrasting ecosystems
No full textInternational audienceSoil biodiversity as a critical component of terrestrial ecosystems and their functioning varies across spatial scales and environmental conditions. However, it remains unclear whether and how biodiversity patterns co-vary among different soil taxa across ecosystems.In this study, we compared diversity patterns of plants, earthworms, nematodes, bacteria, and fungi, as five major groups of soil organisms, across six strongly contrasting ecosystems ranging from mountain peatland to crop fields, including within-ecosystem variation in soil moisture. We hypothesized co-variation in taxonomic richness (alpha diversity) and composition (beta diversity) of multiple groups of soil organisms across ecosystems, moisture conditions and spatial scales.In partial contrast to our initial hypothesis, co-variation in the taxonomic richness among these groups was limited, though significant positive associations were found among bacteria, fungi, and earthworms across all sites. Plant diversity showed distinct associations with soil organism diversity, particularly with earthworms and bacteria, highlighting above-belowground biodiversity linkages. Beta diversity showed substantial co-variation among all soil organism groups, reflecting a spatial coupling of their communities that was influenced by differences in soil moisture conditions. These patterns were more pronounced in near-natural and no-till agroecosystems compared to conventional agricultural systems. Our results highlight that ecosystem type shapes broad-scale taxonomic richness, while local soil moisture critically influences soil biodiversity and spatial community composition, emphasizing the multi-scale drivers of soil biodiversity.</div
Fine Characterization of Co/Fe-Based Materials: Insights into the Influence of Cation Ratios Between 2/2 and 10/2 on Obtaining Layered Double Hydroxides
No full textInternational audienceCo/Fe layered double hydroxides (LDHs) are among the most promising materials for advanced industrial and energy applications. Controlling the synthesis conditions of LDH materials is thus crucial to precisely tailoring cation composition and distribution, thereby regulating surface charge, ion sorption, and electron transfer required for optimal chemical and electrochemical performance. Therefore, characterizing Co/Fe precipitates (chemical composition, purity, morphology, and crystallinity) is also required to further exploit their controlled properties. Thus, solids with Co/Fe cation ratios between 2/2 and 10/2 were synthesized under an air atmosphere, at pH 8 or 11.5. For the first time, multiscale physicochemical techniques (FTIR, TEM-EELS, SEM, AAS, TGA, CHN elemental analysis, and XRD complemented by Rietveld refinement) were used to provide a fully documented characterization of the structure, texture, purity, chemical composition, and thermal properties of Co/Fe LDH-based materials. The combined interpretation of data from these complementary techniques enabled the precise identification and chemical characterization of the mineralogical phases formed. Both acid-base and redox reactions govern the overall Co II /Fe III LDH formation process. Well-crystallized LDHs were synthesized, except for the 2/2 ratio at pH 11.5, which led to the formation of α-Co(OH) 2 , γ-Fe 2 O 3 , and Co 3 O 4 byproducts. A pH value of 8.0 provides valuable LDH materials made of quasi-hexagonal particles with diagonal lengths between 200 and 500 nm. Rietveld refining showed the presence of LDH phases in the range of 95-98%. Multiple local chemical analyses using EDX on chosen particles demonstrated pure 4/2 and 6/2 LDHs. For the 2/2 ratio, the cumulative mass fraction of two LDH-type products consistently reached 97%, distributed between Co/Fe 1.5/2 (71%) and Co/Fe 4/2 (29%). For the 10/2 ratio, only partial Co precipitation was observed, forming 95% Co/Fe LDH phases distributed between Co/Fe 10/2 (72%) and 7/2 (28%)
High-frequency fluorescence monitoring in karst aquifers: A multivariate approach for early detection of anthropogenic contamination of water resources
No full textInternational audienceKarst aquifers play an essential role in drinking water supply, but their vulnerability to anthropogenic pollution, particularly during rainfall events, requires adapted monitoring methods. In this study, we developed an approach combining high-frequency in situ measurements and laboratory analyses to characterise the intensity and occurrence of organic matter fluorescence peaks, in particular Tryptophan-Like Fluorescence (TLF) peaks, associated with faecal contamination. We adapted a background noise correction method based on multiple regression applied to multispectral signals from field fluorometers. A specific calibration in TLF equivalents of the signals from an optical sensor measuring fluorescence at 285 nm is used to quantify contamination peaks. This method was tested on a dataset including 95 samples analysed in the laboratory and high-frequency data spanning 2015–2025 at 15-minute intervals from the Lez karst spring (France), showing its effectiveness in correcting optical interferences and detecting low pollution episodes. The analysis of time series underlined the importance of high-frequency monitoring to capture rapid water flow dynamics, while confirming the indispensable complementarity of laboratory analyses to better discriminate the fluorophores controlling the intensity of high-frequency in situ signals. The results highlight critical contamination periods, particularly in autumn and spring, and confirms the suitability of TLF for Early Warning System (EWS) applications. This approach broadens the methods used for water quality management in karst environments and proposes a methodological framework transferable to other sites
Modeling of the CoSO4-Li2SO4-H2O ternary phase diagram between 283.15 K and 348.15 K
No full textInternational audienceA new set of ternary interaction parameters is proposed to describe the excess properties of aqueous solutions in the CoSO4-Li2SO4-H2O chemical system between 283.15 K and 348.15 K at P = 101.3 kPa, using the Pitzer formalism. The parameters were determined using a combination of (i) experimental solubility values between 283.15 K and 323.15 K coming from the literature and a new set of experimental osmotic coefficients at 298.15 K and 308.15 K, (ii) reliable solid-liquid equilibrium models based on Pitzer equations for the CoSO4-H2O and Li2SO4-H2O binary systems, from literature. The new interaction parameters defined in this study allow to reproduce correctly the change in the hydration state of salts with temperature (Li2SO4.H2O and CoSO4.nH2O with n = 1, 6, 7) as well as their solubility products but they also allow to accurately represent the experimental phase diagram of the CoSO4-Li2SO4-H2O system according to temperature
Improving the identification of pesticide transformation products and assessing their ecotoxicity for aquatic organisms
No full textPlant protection products used in agriculture contain molecules specifically designed to be toxic to target organisms. However, their use can also have unintended effects, posing potential risks to ecosystems and non-target organisms, including humans. Research has deepened our understanding of the links between exposure to these substances and the effects observed in the environment. In particular, studies have highlighted how even low levels of exposure can cause chronic effects on non-target organisms and disrupt ecosystems. These findings underscore the importance of quantifying and characterising these exposures in order to better assess their potential impacts on human health and the environment.International audienceThe TAPIOCA project investigated pesticide transformation products (TPs) in the environment and their ecotoxicity on a selection of aquatic organisms. The project enabled to (i) develop non-targeted analytical methods and apply them to the identification of TPs in various environmental matrices, (ii) improve knowledge of the ecotoxic effects of a selection of pesticides and TPs under controlled laboratory conditions, and (iii) test the benefits of tools for predicting the environmental fate and ecotoxicological effects of TPs relative to their parent substance, in order to provide an initial assessment of the environmental risks arising from the formation of TPs
Assimilation de données pour la prévision des débits d’étiage
No full textWithin the framework of WP3 of the ANR CIPRHES project, data assimilation techniques have been developed and/or evaluated at spatial scales ranging from watershed to the entire country of France. General conclusions common to all of these studies emerge. The first is that assimilating observed streamflows improves the simulation of river flows for historical periods. It appears to have a modest but present effect on low flow forecasts. The results from these studies show a very short persistence of the assimilation contribution in forecasting (less than 10 days). Moreover, the results demonstrate a real interest in terms of operational scores (e.g., anticipating the onset of drought periods). Finally, assimilating groundwater table levels does not seem to improve either the simulation of river flows for historical periods or future river flow forecasts.As a perspective, it is necessary to increase the number of assimilated observation points, either to improve the contribution of assimilation itself, or to enhance the method in order to improve its robustness in more varied hydrological contexts. Finally, the modalities for which a transition to operational use in the PREMHYCE platform could be considered in the future still need to be defined.Dans le cadre du WP3 du projet ANR CIPRHES, des techniques d’assimilation ont été développées et/ou évaluées à des échelles spatiales allant du bassin versant jusqu’à la France entière. Il en ressort des conclusions générales communes à l’ensemble de ces travaux. La première est que l’assimilation des débits observés permet d’améliorer la simulation des débits en périodes historiques. Elle semble avoir un effet modeste mais néanmoins présent sur la prévision des débits d’étiage. Les résultats issus de ces travaux montrent une persistance très courte de l’apport de l’assimilation en prévision (inférieure à 10 jours). De plus, les résultats montre un réel intérêt au regard de scores plus opérationnels (exemple : anticiper le démarrage des périodes de sécheresse). Enfin, l’assimilation des niveaux de nappe ne semble pas apporter d’amélioration ni sur la simulation des débits en période historique, ni sur la prévision future des débits.En perspectives de ces travaux, il est nécessaire d’augmenter le nombre de points d’observation assimilés, soit pour améliorer l’apport de l’assimilation en elle-même, soit pour améliorer la méthode pour qu’elle soit robuste dans des contextes hydrologiques plus variés. Enfin, il reste à définir les modalités pour lesquelles un passage en opérationnel dans la plate-forme PREMHYCE pourrait être envisagé dans le futur
Le renouveau minier en Europe Occidentale
No full textInternational audiencePour ce numéro thématique de la revue Entreprises et Histoire sur Entreprises minières et transitions, nous souhaitons échanger sur le renouveau minier en Europe occidentale à l’heure de la transition et des problèmes de souveraineté. En effet, il est question aujourd’hui de relancer l’activité minière en raison de problématiques énergétiques fortes, et plusieurs projets d’extraction ont été annoncés, que ce soit en Suède ou en France. À partir de ces différents projets, il s’agit de comprendre les politiques, les stratégies et les discours autour d’une relance de l’activité minière qui soulève de multiples questions, de type économique, environnemental et social
A conceptual framework for mineral supply chain traceability: Enabling conditions and core dimensions
No full textInternational audienceCompanies trading in mineral resources must monitor supply chains rigorously, as minerals may originate from conflict-affected areas and present risks like human rights abuses, environmental damage, and corruption. Beyond regulatory pressures mandating ethical sourcing and transparency, consumers, NGOs, employees, and investors increasingly demand robust due diligence and detailed information on material origin. A central element of these practices is traceability, which enables companies to verify that their sourcing aligns with corporate standards and sustainability goals. Despite progress, traceability initiatives remain fragmented, often addressing isolated issues rather than forming a unified framework. The complexity of mineral supply chains, involving numerous actors and diverse requirements, further complicates the implementation of traceability. This study proposes an integrated conceptual framework for mineral supply chain traceability, developed through an extensive review of academic literature, technical and regulatory documents, and refined through expert validation. The framework organises traceability into enabling conditions and core dimensions across five interdependent categories, consisting of a total of twenty factors: Governance and compliance, Supply chain management, Social and environmental impacts, Technology and analytics, and Performance and evaluation. It is emphasised that effective traceability is a systemic task that requires solid institutional structures, coordinated operational practices, meaningful social and environmental commitments, appropriate technological tools, and continuous evaluation mechanisms. Technologies such as blockchain or digital product passports only prove their effectiveness when integrated into favourable conditions. The proposed framework provides policymakers, industry actors and certification bodies with a coherent structure for designing, assessing and strengthening traceability across diverse mineral supply chain
Sensitivity analysis of numerical models of earthquake ground motions using Sobol indices for an extremely shallow earthquake in a complex intracontinental area
No full textInternational audienceDeterministic physic-based earthquake ground motion simulations are a powerful tool for predicting ground motions during earthquakes, especially in areas prone to site effects. However, such simulations require detailed knowledge of the source, path and site properties, which is often lacking in realistic scenarios.In this works, we focus on the Mw4.9 Le Teil earthquake (November 11, 2019, France) aftershocks. We assess the epistemic uncertainties associated with 3D physics-based ground motion simulations of it, including uncertain source location and mechanism, uncertain S-wave/P-wave/density/quality factor structures, as well as complex lithostratigraphic features (marls and limestone alteration, quaternary deposit, and velocity profile inversion).Using a variance-based global sensitivity analysis applied to a dataset of 4096 physics-based high-performance simulations (representing 346 030 single-core CPU hours, i.e. 39 years of computation), we show how these uncertainties impact key output metrics such as Fourier amplitude spectra, peak ground velocity, etc. Our case study is especially interesting as it is an extremely shallow intraplate earthquake in a geologically complex area.The global sensitivity analysis, through computation of first-order Sobol indices, emphasizes the importance of considering the bedrock complexity as observed in the Le Teil area. Conversely, uncertainties added on P-wave velocities, densities and quality factors around the values determined by Brocher et al. (2008) laws are shown to have negligible impact.To further investigate the underlying physical processes, we compare simulations of the Le Teil aftershocks with those of an almost-similar earthquake model with a deeper source (-6200 ± 500 m instead of -1200± 700 m). This comparison helps clarify the relative influence of source-related uncertainties versus those associated with the velocity structure