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Analytical and numerical models describing the evolution of contaminant concentrations in the plume associated with the dissolution of NAPL source and degradation processes were presented in the literature. At real sites and particularly in complex aquifers like chalk, it is difficult to understand how the sources of contaminants evolve with time. 1,1,1-Trichloroethane (1,1,1-TCA) is one of the few compounds with a well-known hydrolysis constant, that can help to improve knowledge of the contaminant sources and transport rates of dissolved contaminants in groundwater by dating the spill. In this work, different scenarios that could explain the evolution of the concentrations of 1,1,1-TCA and its degradation product 1,1-Dichloroethene (1,1-DCE) at a real contaminated site were investigated by analytical and numerical modelling. The results show that (1) the peaks of concentration time series do not correspond to a single contamination event even in the case of a complex medium, (2) the multiphasic behavior of the concentration time series is dictated by the dissolution in a heterogeneous medium, and (3) the persistence of the concentrations can arise from a small residual organic phase or transport in dual domain medium.

International audience; Soils and groundwater are often contaminated by complex organic mixtures also called Non Aqueous Phase Liquids (NAPLs). Several techniques such as drilling, monitoring of soil gas or injection of tracers are traditionally used to quantify NAPLs in aquifers but are complex to perform. The use of natural soil gas such as 222Rn could be an easy and cheap alternative. This method requires the knowledge of the radon NAPL-water partitioning coefficients (Kn-w.). Once spilled on soil, NAPL will undergo degradation (evaporation, effects of sun light among others) and this degradation could impact the Kn-w. This study aims at investigating the partitioning coefficients of complex NAPLs such as commercial diesel fuel and gasoline in relation to degradation such as evaporation and UV-degradation. For that purpose, batch experiments and GCMS investigations were carried out. The results show different Kn-w for the commercial diesel fuel (60.7 ± 6.1) and gasoline (37.4 ± 5.6). The results also show different Kn-w behaviors in relation with degradation. Degraded diesel fuel display opposite Kn-w values (74.8 ± 7.5 and 25.1 ± 2.5 for UV degraded and evaporated diesel fuel, respectively), compared to fresh one. Degraded gasoline shows no significant variations of the Kn-w compared to fresh one. The molecular investigation reveals the removal of the most volatile fraction for the evaporation treatment, whereas UV-degradation do not have pronounced effects on the chromatogram pattern. For the gasoline molecular investigation, no difference is observed between the treatments excepted a very slight removal of the lightest compounds under evaporation. These results show that NAPL degradation have effects on the Kn-w for diesel fuel and no significant effects for gasoline, at least with these degradation paths. This Kn-w variation will have in fine effects on 222Rn activity interpretation and NAPL subsurface quantification.

International audience; The contamination of groundwater resources is a challenge for drinking water supplies. To meet water quality standards, well-field operators need practical solutions to reduce the vulnerability of production wells. Strategies for several combinations ofmanagement variables such as well flow rate or water level in drains, are usually possible to satisfy the required production rate.However, these strategies may lead to contamination issues for the abstracted groundwater. A surrogate transport model wasimplemented in a well field vulnerable to a contaminated stream. An adaptive multi-objective optimization approach is proposed.The objective is to maximize the water production at the well field while minimizing the proportion of stream water abstracted.The optimization problem is adaptive to the stream level, which is a key parameter describing hydrological conditions. Asystematic exploration of management settings is conducted and a three-dimensional Pareto front is extracted. From theseoptimum settings, a practical easy-to-use approach is developed. The well-field operator can adjust production settings tooptimum conditions as a function of the observed stream water level and desired production rate.; La contamination de la ressource en eaux souterraine est un défi pour l’approvisionnement en eau potable. Pour respecter les normes de qualité de l’eau potable, les exploitants ont besoin de solutions pratiques pour réduire la vulnérabilité des puits de production. La mise en place de stratégies jouant sur les schémas de gestion, telles que le débit des puits ou le niveau d’eau dans les drains, sont généralement possibles pour atteindre le débit de production requis. Cependant, ces stratégies peuvent entraîner des problèmes de contamination des eaux souterraines captées. Un modèle équivalent de transport a été mis en œuvre sur un champ captant vulnérable à un cours d’eau contaminé. Une approche d’optimisation multi-objectifs adaptative est proposée. L’objectif est de maximiser la production d’eau tout en minimisant la proportion d’eau du cours d’eau captée. Le problème d’optimisation est adaptatif au niveau du cours d’eau, paramètre clé décrivant les conditions hydrologiques. Une exploration systématique des paramètres de gestion est effectuée et un front de Pareto tridimensionnel est extrait. À partir de ces paramètres optimaux, une approche pratique et facile à utiliser est développée. L’opérateur peut ajuster les paramètres de production aux conditions optimales en fonction du niveau d’eau du cours d’eau observé et du débit de production souhaité.

The Western Pyrenean Jurassic carbonate platform, cropping out on the northerwestern Pyrenees foreland, is a remarkable laboratory for the characterization of dolomitization. With a geodynamic evolution at the interface between margin and chain, as well as the presence of the whole carbonate system at the outcrop,the study of this zone allows to apprehend the crucial parameters of the dolomitization and thus to determine which geodynamic and sedimentary contexts are suitable. The combination of field observations, petrographic, isotopic and microthermometric analyses on fluid inclusions coupled with carbonate U-Pb dating allowed to determine the dolomitization conditions of different localities of this carbonate system cropping out in the chaînons béarnais and the Basque Country.In the Mano (Tithonian) and Meillon (Batho-Callovo-Oxfordian) Formations of the Mail Arrouy (referenceoutcrop) in the Chaînons Béarnais, dolomitization occurred in several stages, spanning the Neocomian (prerift)to the Albian (syn-rift, associated with crustal hyper-thinning and mantle exhumation, accompanied by activesalt tectonics). Both units were first massively dolomitized in near-surface to shallow burial conditions duringNeocomian, likely triggered by the influx of marine-derived waters. Between the Barremian and the Albian, theLower Cretaceous rifting caused the upward influx of hot fluids (T > 160°C), associated with partial to completerecrystallization of the initial dolomites. Subsequent dolomites precipitated in both formations during the Albian,from distinct hot fluids (with evaporite-derived water in the Meillon and clay water in the Mano) as vein- andpore-filling cements. Finally, a last episode of dolomite cementation occurred only in the vicinity of faults andvolcanic intrusions during the Albian, from hydrothermal water recording the mixing of mantle-, crustal- andevaporites-derived waters and the highest temperatures in both formations (T > 260°C). Subsequent quartz andcalcite cement precipitation record a temperature decrease in a post-rift to inversion context.Southward (Layens anticline), dolomitization was only partial in the Meillon Formation. The upwelling of hot fluids during the rifting induced a partial recrystallization of this outcrop, located on the necking zone of the rift basin. Dedolomitization was also strongly present, induced by an extended emersion period, until the rifting, causing an influx of meteoric water synchronous with this episode of hydrothermalism.In the Basque Country, the dolomitic Meillon and Mano Formations lateraly pass to the distal formationsof Microfilament limestones and Hosta marls. In these compact and marl-rich formations, only a few traces ofdolomite are present as vein fillings. Calcite was ubiquitous during the Albian, and partially to completelyreplaced the dolomites initially in place. Thus, the distal zone of this carbonate system was also affected bydolomitization, during the Cretaceous rifting, probably caused by the upwelling of hot fluids.The dolomitization of the West Pyrenean platform was primarily controlled by the sedimentary andclimatic depositional environment allowing the influx of seawater generating early massive dolomitization.Cretaceous rifting inducing thermal anomalies, combined with the presence of a significant salt layer and salttectonics represent the second control, inducing massive recrystallization and dolomitic cementationsthroughout the basin. The stratigraphic architecture of the carbonate system also conditions the distribution ofthe dolomite with the presence of traces of cement in the distal environment as opposed to the abundance ofdolomite observed in the more internal environment. Thus, the distribution of dolomite on carbonate platform onsalt-rich hyperthinned passive margin depends essentially on the correlation between the sedimentology of thecarbonate system and the paleogeography of the margin., Affleurant sur le versant nord des Pyrénées, la plate-forme carbonatée jurassique ouest-pyrénéenne constitue un laboratoire d’étude unique dans la caractérisation de la dolomitisation. Avec une évolution géodynamique à l’interface entre marge et chaine, ainsi que la présence de l’ensemble du système carbonate ́à l’affleurement, l’étude de cette zone permet d’appréhender les paramètres cruciaux de la dolomitisation et ainsi déterminer quels contextes géodynamiques et sédimentaires s’avèrent propices. La combinaison d’observations de terrain, d’analyses pet́ rographiques, isotopiques et microthermomet́riques sur inclusionsfluides couplée à la datation U-Pb a permis de déterminer les conditions de la dolomitisation de différentes localités de ce système carbonaté dans les Chaînons Béarnais et le Pays basque.Dans les Formations de Mano (Tithonien) et de Meillon (Batho-Callovo-Oxfordien) du Mail Arrouy, la dolomitisation se fait en plusieurs étapes du Néocomien (anté-rift) à l’Albien (syn-rift associe ́ à un hyperamincissement crustal et une exhumation mantellique, accompagné d’une tectonique gravitaire). Dans un premier temps, ces formations ont éte ́ affectées par une dolomitisation massive en domaine peu profond à émergent, liée à l’influx d’eau de mer durant la période d’émersion puis de ré-ennoiement de la plate-forme au Néocomien. Du Barreḿ ien a ̀ l’Albien, la remontée de fluides chauds (T > 160°C) à affinité évaporitique provoquée par le rifting, a induit la recristallisation complète à partielle de la Formation de Meillon. La précipitation de ciments dolomitiques a ̀ partir de fluides chauds distincts (a ̀ affinité évaporitique dans le Meillon et générés par la diagenèse argileuse dans le Mano), a suivi dans les deux formations. Une dernière précipitation de dolomies baroques (saddle) à proximité de failles enregistre les fluides les plus chauds (T >260°C), témoignant également d’une contribution crustale, mantellique et évaporitique durant l’Albien. Par la suite, la précipitation de quartz et de calcites enregistre une diminution de la température lors du post-rift et de la compression pyrénéenne. En direction du sud (chaînons du Layens), la dolomitisation est seulement partielle dans la Formation du Meillon. La remontée de fluides chauds durant le rifting a induit une recristallisation partielle de cet affleurement excentré du coeur du rift. La dédolomitisation est également présente, induite par une émersion prolongée jusqu’au rifting, provoquant un influx d’eau météorique.Dans le Pays basque, les Formations de Meillon et de Mano passent latéralement aux faciès distaux des Calcaires à Microfilaments et des Marnes d’Hosta. Dans ces formations, seulement quelques traces de dolomies sont présentes. La calcite est omniprésente durant l’Albien, et remplace partiellement à complètement les dolomites initialement en place. Ainsi, la zone distale de ce système carbonate ́ a également éte ́ affectée par une dolomitisation, pendant ou avant le rifting crétacé. La dolomitisation de cette plate-forme est premièrement contrôlée par l’environnement de dépôt sédimentaire permettant l’influx d’eau de mer générant une dolomitisation massive. Le rifting crétacé induisant des anomalies thermiques, combiné à de la tectonique salifère représente le second contrôle, induisant une recristallisation massive ainsi que des cimentations dolomitiques dans l’ensemble du bassin.L’architecture stratigraphique du système carbonaté conditionne également la répartition de la dolomie avec la présence de traces de ciment en milieu distal opposée à l’abondance de dolomies observée en milieu plus interne. Ainsi, la répartition de la dolomie sur une plate-forme carbonateé en contexte de marge salifère hyper-étirée et inversée dépend essentiellement de la corrélation de la sédimentologie du système carbonaté et de la paléogéographiede la marge.

International audience; The inverse problem of groundwater models is often ill-posed and model parameters are likely to be poorly constrained. Identifiability is improved if diverse data types are used for parameter estimation. However, some models, including detailed solute transport models, are further limited by prohibitive computation times. This often precludes the use of concentration data for parameter estimation, even if those data are available. In the case of surface water-groundwater (SW-GW) models, concentration data can provide SW-GW mixing ratios, which efficiently constrain the estimate of exchange flow, but are rarely used. We propose to reduce computational limits by simulating SW-GW exchange at a sink (well or drain) based on particle tracking under steady state flow conditions. Particle tracking is used to simulate advective transport. A comparison between the particle tracking surrogate model and an advective–dispersive model shows that dispersion can often be neglected when the mixing ratio is computed for a sink, allowing for use of the particle tracking surrogate model. The surrogate model was implemented to solve the inverse problem for a real SW-GW transport problem with heads and concentrations combined in a weighted hybrid objective function. The resulting inversion showed markedly reduced uncertainty in the transmissivity field compared to calibration on head data alone.

International audience; No abstract available

International audience; We measured the streaming potential coupling coefficient of natural saturated and unsaturated carbonate rocks. Saturation was achieved with NaCl brines with salinities ranging from 2 ´ 10 −3 to 2.0 mol L −1. The magnitude of the coupling coefficient increased with decreasing salinity, similarly to the trend observed for sandstones. The permeability had a low impact on the values of the streaming potential coupling coefficient at high and low salinity. The zeta potential was calculated at full saturation using a modified version of the Helmholtz-Smoluchowski equation that accounts for surface electrical conductivity. Under atmospheric conditions, the magnitude of the zeta potential decreased with the increase in salinity. We also explored the relationships between the streaming potential coupling coefficient and water saturation in three partially saturated limestones using a steady-state flow experiment. We found good agreement between the van Genuchten approach and experimental data, and fitted both the relative per-meability and capillary pressure curves with the same value of the van Genuchten exponent m v. We validated the predictive water relative permeability model described by Revil in water-wet rocks when the second fluid phase is non-polar.

International audience; Emergent Contaminants (ECs) including nanoparticles (NPs) are preoccupation cause for concern for the scientific community, industrials, territorial communities and the general public. High production volume, potential release from consumer product, environmental exposure, we need to measure the environmental concentrations of NPs and their behavior in natural waters. This is too complicated given the complexity of natural particles and the similarity of Engineering NanoParticles (ENPs) with Natural NanoParticles (NNPs) called here NPs. Thus, we need new methods/protocols dedicated to NPs as ECs which cover the sampling strategy, the analysis and the data valorization using new approaches, theory, paradigms! Our objective is to propose a global approach addressing the above mentioned concerns conveying: sampling, analysis and concept(s) dedicated to Metallic Trace Elements (MTEs) and Nanoparticles (NPs). • Sampling: A crucial point due to the representativeness of the samples regarding a water mass (notion of flux) whose matrix integrates organic matter, chemical elements (from the major to the trace) ligands, biological compounds and contaminants such as MTEs and NPs? • Analysis: Once a representative sample is obtained, how to analyze with minimum artefacts (fractionation, metastable complexes over time, endogenous reaction between the different components, etc.)? What are the basic parameters necessary for understanding the fate of TMEs and NPs in the water column? • Concept(s): it should be holistic which means able to describe the main scenario allowing for consideration of the parameters controlling the fate and behavior of MTE and NPs. Holistic approach consists of sampling devices adapted to the target elements, user-friendly, easy to analyze using a dedicated analytical platform that fits the concept of physical chemical speciation.

International audience; From a natural underground cavity and two locations situated in a well, three CO 2 injections have been designed and performed under controlled conditions in order to study its migration along the carbonate vadose zone and to test geochemical and geophysical techniques. After the understanding of the natural CO 2 dynamics and the establishment of a baseline, some numerical simulations have been performed to help to optimize the monitoring strategy (spatially and temporally). A mixture of CO 2 + noble gases has been injected and the results show that CO 2 subsurface leakage can be anticipated thanks to these inert chemical gases used as tracers (He + Kr).The geochemical and geophysical monitoring approaches are very complementary.

Background Lead is well known environmental pollutant, which can cause toxic effects in multiple organ systems. However, the influence of lead oxide nanoparticles, frequently emitted to the environment by high temperature technological processes, is still concealed. Therefore, we investigate lead oxide nanoparticle distribution through the body upon their entry into lungs and determine the microscopic and ultramicroscopic changes caused by the nanoparticles in primary and secondary target organs. Methods Adult female mice (ICR strain) were continuously exposed to lead oxide nanoparticles (PbO-NPs) with an average concentration approximately 106 particles/cm3 for 6 weeks (24 h/day, 7 days/week). At the end of the exposure period, lung, brain, liver, kidney, spleen, and blood were collected for chemical, histological, immunohistochemical and electron microscopic analyses. Results Lead content was found to be the highest in the kidney and lungs, followed by the liver and spleen; the smallest content of lead was found in brain. Nanoparticles were located in all analysed tissues and their highest number was found in the lung and liver. Kidney, spleen and brain contained lower number of nanoparticles, being about the same in all three organs. Lungs of animals exposed to lead oxide nanoparticles exhibited hyperaemia, small areas of atelectasis, alveolar emphysema, focal acute catarrhal bronchiolitis and also haemostasis with presence of siderophages in some animals. Nanoparticles were located in phagosomes or formed clusters within cytoplasmic vesicles. In the liver, lead oxide nanoparticle exposure caused hepatic remodeling with enlargement and hydropic degeneration of hepatocytes, centrilobular hypertrophy of hepatocytes with karyomegaly, areas of hepatic necrosis, occasional periportal inflammation, and extensive accumulation of lipid droplets. Nanoparticles were accumulated within mitochondria and peroxisomes forming aggregates enveloped by an electron-dense mitochondrial matrix. Only in some kidney samples, we observed areas of inflammatory infiltrates around renal corpuscles, tubules or vessels in the cortex. Lead oxide nanoparticles were dispersed in the cytoplasm, but not within cell organelles. There were no significant morphological changes in the spleen as a secondary target organ. Thus, pathological changes correlated with the amount of nanoparticles found in cells rather than with the concentration of lead in a given organ. Conclusions Sub-chronic exposure to lead oxide nanoparticles has profound negative effects at both cellular and tissue levels. Notably, the fate and arrangement of lead oxide nanoparticles were dependent on the type of organs. Electronic supplementary material The online version of this article (10.1186/s12989-017-0236-y) contains supplementary material, which is available to authorized users.

International audience; PurposeBasic slags are alkaline by-products of the steel industry with potential properties to ameliorate nutrient supply and metal stabilisation in contaminated soils. This study aimed at investigating the potential of a P-spiked Link Donawitz slag and a conventional basic slag called Carmeuse for the aided phytostabilisation of a Cu-contaminated soil at a wood treatment site. The effects of basic slag addition on Cu fractionation, mobility and (phyto) availability were assessed.Materials and methodsBoth slags were incorporated at 1 % w/w into the Cu-contaminated soil phytostabilised with Cu-tolerant plants, using either outdoor lysimeters or a field plot. Untreated soil (UNT), amended soils with the P-spiked Link Donawitz slag (PLDS) and the conventional slag (CARM) respectively, and a control soil (CTRL) were sampled, potted and cultivated with dwarf bean. Physico-chemical analysis, determination of total soil elements and a Cu-sequential extraction scheme were carried out for all soils. Physico-chemical characteristics of soil pore water and Cu speciation (rhizon, ion selective electrode and diffusive gradient in thin film (DGT)) were determined. Shoot dry weight yield and leaf ionome (i.e. all inorganic ions present in the primary leaves) of dwarf beans were investigated.Results and discussionThe slag incorporation at only 1 % w/w increased the soil pH from 1.5 to 2 U and electrical conductivity in soil pore water by three times. The residual Cu fraction increased for both slag amended soils compared to the UNT soil by six times in parallel to the decrease of the Cu oxidisable fraction (1.5 times) and to a less extent the reducible fraction. The incorporation of both slags did not reduce the total dissolved Cu concentration in the soil pore water but significantly reduced the real dissolved Cu concentration ca five times, the Cu labile pool as measured by DGT (at least two times) and the Cu phytoavailability. The dwarf bean total biomass was also improved with the slag addition especially for the P-spiked Linz–Donawitz slag.ConclusionsThe addition of both slags in the contaminated soil increased Cu concentration in the residual fraction and thus reduced its potential mobility. Though the total dissolved Cu soil pore water concentration remained identical, its speciation changed as the real dissolved fraction diminished and lowered the Cu bioavailability. The addition of small amount of P-spiked Linz–Donawitz and Carmeuse slags was beneficial for this Cu-contaminated soil in the context of aided phytostabilisation.

International audience; The dynamic response of four unstable rock compartments in the Alps has been studied using the ambient vibration technique, with the aim of identifying precursors to rockfalls. The test sites present various geological settings (limestone, argillite, and shale-sandstone series), failure mechanisms and volumes. The ambient vibration spectra measured on the unstable compartments systematically showed clear energy peaks at specific frequencies, in contrast with records made on the adjacent stable rock masses. These predominant frequencies were interpreted as resonant frequencies of the unstable compartments, in agreement with 2-D modal analysis. In the horizontal plane, ground motion at the fundamental frequency was found to be systematically parallel to the line of maximum slope gradient, and perpendicular to the main bounding fracture observed at most of the sites. The fundamental frequency of each prone-to fall compartment shows reversible variations related to temperature fluctuations at different timescales, with a significant contrast in magnitude and phase shift between sites. At the more fractured site, resonance seems to result from a contrast in internal rigidity between the compartment and adjacent rock mass, rather than from decoupling along a rear fracture, which is the mechanism observed at the three other sites. No change in fundamental frequency resulting from damage was observed over the period of study.

In this study, the distribution of labile trace metals (LTMs; Cd, Co, Cr, Cu, Ni, Pb, and Zn) in a semi-urban runoff collector was examined to assess its influence to a natural aqueous system (Jalle River, Bordeaux, France). This river is of high importance as it is part of a natural reserve dedicated to conserving aquatic flora and fauna. Two sampling campaigns with a differing precipitation condition (period 1, spring season; and period 2, summer season associated with storms) were considered. Precipitation and water flow were monitored. The collector is active as it is receptive to precipitation changes. It influences the river through discharging water, contributing LTMs, and channeling the mass fluxes. During period 2 where precipitation rate is higher, 25 % of the total water volume of the river was supplied by the collector. LTMs were detected at the collector. Measurements were done by using diffusive gradient in thin films (DGT) probes deployed during 1, 7, and 14 days in each period. The results showed that in an instantaneous period (day 1 or D1), most of these trace metals are above the environmental quality standards (Cd, Co, Cr, and Zn). The coefficient of determination (r 2 > 0.50) employed confirmed that the LTM concentrations in the downstream can be explained by the collector. While Co and Cr are from the upstream and the collector, Cd, Cu, and Zn are mostly provided by the collector. Ni, however, is mostly delivered by the upstream. Using the concentrations observed, the river can be affected by the collector in varying ways: (1) adding effect, resulting from the mix of the upstream and the collector (if upstream ˂ downstream); (2) diluted (if upstream ˃ downstream); and (3) conservative or unaffected (upstream ~ downstream). The range of LTM mass fluxes that the collector holds are as follows: (1) limited range or ˂10 g/day, Cd (0.04–1.75 g/day), Co (0.08–05.42 g/day), Ni (0.06–1.45 g/day), and Pb (0.08–9.89 g/day); (2) moderate range or 11–50 g/day, Cr (0.23–33.26 g/day) and Cu (0.77–37.88 g/day); and (3) wide range or ˃50 g/day, Zn (26.33–676.61 g/day). Hence, the collector is a major source of concern in terms of contamination. This is as the water with considerable LTMs is channeled openly to the river without any treatment.

International audience

International audience; This paper reports on the aquatic chemistry of trace elements in terms of spatial and temporal distribution, but also pollution sources in the transboundary watershed of the Seversky Donets River (Ukraine/Russia). Bed sediments and filtered water were collected from the Udy and Lopan Rivers at sites from the river source in the Belgorod region (Russia) to rural and urban areas in the Kharkiv region (Ukraine) in May and August 2009. Priority trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn), an urban tracer (Ag) and additional metals (Co, Mo, V) and Th were measured in stream water and sediments. The low levels and variability of Th-normalized concentrations indicated the absence of geochemical anomalies in the upstream part of the rivers and suggested that these data represent a regional baseline for trace elements in bed sediments. In contrast, water and sediments within the city of Kharkiv were contaminated by Ag, Pb, Cd, Cu, Cr and Zn, which are mainly attributed to municipal wastewater inputs and urban run-off. Results of the environmental quality assessment showed that element concentrations in the sediments can be considered as potentially toxic to aquatic organisms in sites downstream of the wastewater discharges.

As a result of the massive irrigation development during the Soviet Union era and intensive chemization of agriculture, the surface runoff quality has been degraded in this arid and endorheic region. Moreover hydraulically related groundwater has also been affected. Excessive irrigation has lead to land salinization, which now threatens the soil quality of significant areas where crop yields would be at risk in the future. Since the collapse of the Soviet Union, institutional changes have been undertaken for the management of natural resources and water infrastructure. At present, underdeveloped and inadequate systems have been practiced with respect to groundwater use and management. This paper analyzes the present extent of groundwater resources with consideration to their reserves, quality evolution, and to technical, institutional and transboundary management practices in Uzbekistan.

The Barada and Awaj basin is the most important and extensively used water basin in Syria. Chemical and isotopic data of groundwater have been used to determine the spatial distribution of hydrogeological features in the upper part of Awaj River catchment area located southwest of this basin. Hydrogeochemical evolution of groundwater reveals the domination of dissolution/precipitation mechanisms in these very complex stratigraphic sequences. The dissolution of carbonate rocks as well as reverse cation exchange processes seem to be the main factors controlling groundwater mineralization. The isotopic composition of precipitation and groundwater indicate that the modern-day atmospheric precipitation is the main source of groundwater recharge before an important evaporation occurred. The isotopic data also imply an existence of hydraulic connection between the different aquifers system. The results obtained allowed us to delineate two main spatial groundwater zones within the study area with different flow components. The south, central and eastern parts are considered to be one zone which is characterised by a shallow horizontal flow associated with active interaction between groundwater and hosting rocks. The nitrate concentrations in this zone are attributed to anthropogenic sources. The second zone consists in south-western, western and north-western parts where the karstic features are well developed mainly in the Jurassic strata. This zone is characterized by a high vulnerability to pollution confirmed by high values of nitrate coming from sewage water. The deep vertical groundwater flow component seems to be dominant in this zone and is controlled by fractures and geological structures.

International audience; Ground surface analysis of CO2 emissions with δ13C determination is experimentally demonstrated to be a potential methodology to monitor, on line, the dynamics of petroleum-hydrocarbon biodegradation in soil aquifers, thanks to the improvement of the Isotopic Ratio Infra Red Spectroscopy technique. Biodegradation rate of remaining hydrocarbon substrates in groundwater can be quantified using basic application of the Rayleigh equations, by δ13CCO2 analysis released at ground surface above the pollution plume instead of usual approaches based on groundwater hydrocarbons δ13C analysis, when physical and chemical properties for the contaminated site meet appropriate conditions.The validation approach for that gasoline contaminated specific site is discussed and verified by comparison of first order attenuation rate constant determined from δ13CCO2 analysis emitted at ground surface and from δ13CTOLUENE analysis in ground water. A kinetic fractionation factor α of 0.9979 (or ε value of −2.1 ± 0.5‰) is estimated for the biodegradation of the most reactive hydrocarbon substrates (TEX). The treatment of this Rayleigh equations by linear regression of δ13CCO2 values along the predominant direction of groundwater flow leads to the following results and conclusions for that site: (i) first order biodegradation rate constants (and annual variation) are maximum after the activation of a Permeable Reactive Barrier (PRB) in May 2014: 0.92(+0.29–0.17) year−1, and during July and October: 0.46(+0.14–0.09) year−1 and minimum in mid-winter in February 2015: 0.17(+0.05–0.03) year−1, given by the estimation range for ε. These results are in the lower range with reported in literature for similar contaminated sites (1.6–18 year−1) considering natural attenuation under sulfate reducing conditions and (ii) the seasonal variation of the first order biodegradation rate constant is mainly correlated with the seasonal variation of the CO2 flux, where maximum values are in summers and minimum values in winters. Both seasonal variations are mainly due to the annual cycle of the natural biodegradation activity at the scale of the pollution plume, rather than the activation of the PRB.This work demonstrates that δ13CCO2 analysis released at ground surface from biodegradation of groundwater hydrocarbons could provide, under characterized and appropriate conditions, a non-intrusive (without soil samplings), fast, and low-cost online method to monitor and therefore to optimize soil remediation processes in real time. (Monitored Natural Attenuation or Enhanced Bioremediation).

International audience; The spatio-temporal trend of trace metals (Cd, Co, Cr, Cu, Ni, Pb, and Zn) in a tropical urban estuary under the influence of monsoon was determined using diffusive gradient in thin films (DGT) in situ samplers. Three different climatic periods were observed: period 1, dry with dredging activity; period 2, intermediate meaning from dry to wet event; and period 3, wet having continuous rainfall. Conforming to monsoon regimes, these periods correspond to the following: transition from winter to summer, winter, and summer monsoons, respectively. The distinction of each period is defined by their specific hydrological and physico-chemical conditions. Substantial concentrations of the trace metals were detected. The distribution and trend of the trace metals under the challenge of a tropical climate were able to follow using DGT as a sensitive in situ sampler. In order to identify the differences among periods, statistical analyses were performed. This allowed discriminating period 2 (oxic water) as significantly different compared to other periods. The spatio-temporal analysis was then applied in order to distinguish the trend of the trace metals. Results showed that the trend of trace metals can be described according to their response to (i) seasonal variations (Cd and Cr), (ii) spatio-temporal conditions (Co, Cu, Ni, and Pb), and (iii) neither (i) nor (ii) meaning exhibiting no response or having constant change (Zn). The correlation of the trace metals and the physico-chemical parameters reveals that Cd, Co, Cu, and Cr are proportional to the dissolved oxygen (DO), Cd and Ni are correlated pH, and Zn lightly influenced by salinity.

In developing countries such as Syria, the lack of hydrological data affects groundwater resource assessment. Groundwater models provide the means to fill the gaps in the available data in order to improve the understanding of groundwater systems. The study area can be considered as the main recharge area of the eastern side of Barada and Awaj basin in the eastern part of Mt. Hermon. The withdrawal for agricultural and domestic purposes removes a considerable amount of water. The steady-state three-dimensional (3D) groundwater model (FEFLOW which is an advanced finite element groundwater flow and transport modeling tool), was used to quantify groundwater budget components by using all available data of hydrological year 2009–2010. The results obtained may be considered as an essential tool for groundwater management options in the study area. The calibrated model demonstrates a good agreement between the observed and simulated hydraulic head. The result of the sensitivity analysis shows that the model is highly sensitive to hydraulic conductivity changes and sensitive to a lesser extent to water recharge amount. Regarding the upper aquifer horizon, the water budget under steady-state condition indicates that the lateral groundwater inflow from the Jurassic aquifer into this horizon is the most important recharge component. The major discharge component from this aquifer horizon occurs at its eastern boundary toward the outside of the model domain. The model was able to produce a satisfying estimation of the preliminary water budget of the upper aquifer horizon which indicates a positive imbalance of 4.6 Mm3·y−1.

International audience; Groundwater withdrawals can reduce aquifer-to-stream flow and induce stream-to-aquifer flow. These effects involve potential threats over surface water and groundwater quantity and quality. As a result, the description of stream-aquifer flow in space and time is of high interest for water managers. In this study, the EauDyssée platform, an integrated groundwater/surface water model is extended to provide the distribution of stream-aquifer flow at the regional scale. The methodology is implemented over long periods (17 years) in the Seine river basin (76 375 km 2 , France) with a 6 481 km long simulated river network. The study scale is compatible with the scale of interest of water authorities, which is often larger than study scales of research projects. Net and gross stream-aquifer exchange flow are computed at the daily time step over the whole river network at a resolution of 1 km. Simula-tion results highlight that a major proportion of the main stream network (82 %) is supplied by groundwater. Groundwater withdrawals induce a reduction of net aquifer-to-stream flow (−19 %) at the basin scale and flow reversals in the vicinity of pumping locations. 140 Pryet et al. Such an integrated model provided at the appropriate regional scale is an essential tool provided to water managers for the implementation of the EU Water Framework Directive.

International audience

International audience; Fundamental processes taking place in UV and IR laser ablation and their significance for LA-ICP-MS measurements were investigated with synthetic glassy materials. LA-ICP-MS experiments were conducted on several vitreous and crystallized matrices with different composition using two Nd∶YAG laser ablation systems operating at 1064 nm and 266 nm. Macro-scale effects of the laser factors and matrix properties were evaluated with ICP-MS detection. In-situ investigation of the laser ablation process was carried out at the micro-scale to assess physical and chemical transformations of the original material, based on electron probe microanalysis of ablation products collected on filters and laser impacts. Fragments and beads in the 1–10 µm range enriched in refractory elements (Ca, Al) were characteristic of IR laser ablation, whereas sub-microscopic particles with similar composition to the original matrix were found for UV laser ablation. LA-ICP-MS response factors for matrix and minor elements appeared to be dependent on both the chemical composition and structure of the matrix (up to 30% and 60% for the UV and IR laser, respectively) and were also different for the two lasers by a factor 10. The use of La, a refractory matrix element, as an internal standard could compensate for differences in the ablation yield and thus limit matrix effects. However, fractionation effects were observed for the IR laser and also, to a lesser extent, with the UV one for volatile elements (e.g., Pb, As, B, Cs). Elemental fractionation effects were correlated with the oxide melting point of the elements as the LA-ICP-MS response factors for the IR laser normalized by the UV ones showed a linear relation with this parameter. At the micro-scale, the samples underwent physical and chemical differentiation that could be explained in terms of fusion, vaporization and fragmentation, resulting in the recombination of the analytes in the ablation products.

International audience; In this paper we show that preparation of Ag doped hydroxyapatite by an adapted co-precipitation method at 100°C has several advantages over other techniques. Specifically, it can generate highly crystalline nanopowder Ag:HAp which could be used for implantable medical devices. The XRD of HAp (xAg = 0) and Ag:HAp (xAg = 0.05, and xAg = 0.4) also demonstrates that powders obtained by co-precipitation at 1000C exhibit the apatite characteristics with good crystal structure and no new phase or impurity is found. The SEM results suggested that Ag+ doping had little influence on the morphology and dimension of the samples. It can be seen that all the samples consist of elipsoidal particles. The antibactericidal activity of Ag:HAp-NPs with xAg = 0, xAg = 0.05, and xAg = 0.4 on Bacilus and E.coli ESBL 1576 were presented. The Ag:HAp-NPs with xAg = 0.05, and xAg = 0.4 inhibited the biofilm development both by the gram-positive (Staphylococcus aureus 0364) and the gram-negative (Providencia stuartii 1116) strains. On the other hand, our studies have shown that Ag:HAp with xAg = 0 had no antibacterial activity against gram-positive and gram-negative bacteria.

International audience; The potential of the Diffusive Gradient Thin-Films (DGT) as a supplemental method for water quality monitoring was employed has been tested through 3 sampling campaigns to measure the trace metals (Cd, Co, Cr, Cu, Pb, Ni and Zn) present in the surface water of a highly urbanized river. Specifically, the study done in the Pasig River (Philippines) seeks to: assess the applicability of DGT passive sampler in an urban context exhibiting highly contrasted hydrological conditions (greatly influenced by episodic events) and sediment disturbance (dredging) and provide proposal for a better water management. The results indicate that: (1) DGT is highly recommended as part of a routine analysis for water quality monitoring; (2) DGT are able to capture the fluxes even in very contrasted flow regimes; (3) DGT are suitable to trace the labile fluxes of metals from the lake to the estuary; and (4) at the confluence of the Marikina River water management should be intensified. Moreover, recommendations were made for developing pertinent water monitoring protocol and management scheme.

International audience; The sorption of inorganic elements on carbonate minerals is well known in strictly controlled conditions which limit the impact of other phenomena such as dissolution and/or precipitation. In this study, we evidence the behavior of Zn(II) (initially in solution) and two trace elements, Mn(II) and Sr(II) (released by carbonate dissolution) in the context of a leakage from a CO 2 storage site. The initial pH chosen are either equal to the pH of the water-CO 2 equilibrium (~2.98) or equal to the pH of the water-CO 2-calcite system (~4.8) in CO 2 storage conditions. From this initial influx of liquid, saturated or not with respect to calcite, the batch experiments evolve freely to their equilibrium, as it would occur in a natural context after a perturbation. The batch experiments are carried out on two natural carbonates (from Lavoux and St-Emilion) with P CO 2 = 10 À3.5 bar, with different initial conditions ([Zn(II)] i from 10 À4 to 10 À6 M, either with pure water or 100 g/L NaCl brine). The equilibrium regarding calcite dissolution is confirmed in all experiments, while the zinc sorption evidenced does not always correspond to the two-step mechanism described in the literature. A preferential sorption of about 10% of the concentration is evidenced for Mn(II) in aqueous experiments, while Sr(II) is more sorbed in saline conditions. This study also shows that this preferential sorption, depending on the salinity, is independent of the natural carbonate considered. Then, the simulations carried out with PHREEQC show that experiments and simulations match well concerning the equilibrium of dissolution and the sole zinc sorption, with log K Zn(II)~2 in pure water and close to 4 in high salinity conditions. When the simulations were possible, the log K values for Mn(II) and Sr(II) were much different from those in the literature obtained by sorption in controlled conditions. It is shown that a new conceptual model regarding multiple Trace Elements (TE) sorption is required, to enable us to better understand the fate of contaminants in natural systems. Résumé-Comportement du Zn(II), Mn(II) et Sr(II) au sein d'un système réservoir carbonate naturel. Partie 1 : impact de la salinité, du pH initial et de la concentration en Zn(II) en conditions atmosphériques-La sorption d'éléments inorganiques sur les minéraux carbonatés est bien connue

Airborne lidar systems have become a source for the acquisition of elevation data. They provide georeferenced, irregularly distributed 3D point clouds of high altimetric accuracy. Moreover, these systems can provide for a single laser pulse, multiple returns or echoes, which correspond to different illuminated objects. In addition to multi-echo laser scanners, full-waveform systems are able to record 1D signals representing a train of echoes caused by reflections at different targets. These systems provide more information about the structure and the physical characteristics of the targets. Many approaches have been developed, for urban mapping, based on aerial lidar solely or combined with multispectral image data. However, they have not assessed the importance of input features. In this paper, we focus on a multi-source framework using aerial lidar (multi-echo and full waveform) and aerial multispectral image data. We aim to study the feature relevance for dense urban scenes. The Random Forests algorithm is chosen as a classifier: it runs efficiently on large datasets, and provides measures of feature importance for each class. The margin theory is used as a confidence measure of the classifier, and to confirm the relevance of input features for urban classification. The quantitative results confirm the importance of the joint use of optical multispectral and lidar data. Moreover, the relevance of full-waveform lidar features is demonstrated for building and vegetation area discrimination.

The development of predictive models for the long term evolution of nuclear waste glass requires the complete knowledge of the glass dissolution at the laboratory scale. A new approach was developed to determine the initial reaction during the first steps of experience, a new concept was developed, based on the combination of dynamic leaching test and the characterization of the altered materials. With this experimental set-up it is possible to follow in real time the glass alteration process at a fine temporal scale. The results put in evidence a singular behaviour of the lanthanide, shown by a concentration peak of La, Nd and Ce after 2 h and a quick decrease of their concentration measured on line in the solution during the leaching test. This fact is directly linked to the development of an interphase (altered layer which differs from the initial solid by its texture, structure and chemical composition) at the interface of the glass surface and the leaching solution. This work is an attempt to integrate the formation of the alteration products (here the interphase) during leaching into the dissolution mechanisms of a nuclear waste glass. A model is proposed and discussed.

International audience; The Early Cretaceous hyperextended Mauléon rift is localized in the north-western Pyrenean orogen. We infer the Tertiary evolution of the Mauléon basin through the restoration of a 153 km-long crustal-scale balanced cross-section of the Pyrenean belt, which documents at least 67 km (31%) of orogenic shortening in the Western Pyrenees. Initial shortening, accommodated through inversion of inherited crustal structures, led to formation of a pop-up structure, in which the opposite edges underwent similar shortening with different tectonic reactivation styles, localized versus. distributed. Underthrusting of the Iberian margin accommodated further convergence, forming the Axial Zone antiformal stack of crustal nappes within a lithospheric pop-up. Thin-skinned and thick-skinned structures propagated outwardfrom the heart of this pop-up, a block of strong mantle acting as a buttress inhibiting complete inversion of the Mauléon rift basin.This work is part of the OROGEN project, cofunded by Total S.A., BRGM and Institut national de sciences de l'Univers (INSU).

International audience; Despite Tertiary Pyrenean orogenesis, the Early Cretaceous Mauléon hyperextended basin remains preserved in the heart of a lithospheric pop-up structure. A multidisciplinary approach combining Raman spectroscopy of carbonaceous material, paleostress reconstructions, seismic interpretations and 3D implicit geological modeling yields evidence, from the outcrop to the lithospheric scale, for the presence of N20°-oriented transfer zones. The thrust segments of the N120°-oriented Lakhoura and North Pyrenean Frontal thrust systems, defining the edges of the Mauléon basin pop-up, branch into these transfer zones and define corridors with differing amounts of shortening. This overall structural pattern defines drawer-like structures allowing the closure, by stages, of the former rift domain. This concept can be applied at both the crustal and the lithospheric scale. This study clarifies the role of inherited lithospheric autochthonous transfer zones in the reactivation of a hyperextended rift basin and bears upon the origin of the non-cylindrical shape of the Pyrenean belt.

Engineering school; Frost and drought limit the distribution of species at the rear and leading edges. Because of global warming, these two constraints will increasingly coexist. Within the framework of the DECLIC project, a database on the frost resistance of woody species has been compiled, the analysis of which aims to predict the evolution of forests due to these climate changes. The results show that evergreen species are less hardy than deciduous ones and that gymnosperms are hardier than angiosperms. Moreover, frost resistance is related to the geographical position of the species and correlated non-linearly to the climatic conditions of its distribution niche: thus, the most resistant species are associated with harsher climates and higher altitudes and latitudes. Crossing of freezing and drought data showed that in angiosperms, freezing resistance excludes drought resistance and vice versa. In gymnosperms, on the other hand, these two resistances can coexist. Since drought and frost affect the same physiological processes, such as photosynthesis and transpiration, and have the same consequence, namely dehydration, a trade-off between drought and frost resistance could be considered.; Le gel et la sécheresse limitent la distribution des espèces aux marges avant et arrière de leur niche. Dans un contexte de changement climatique, ces deux contraintes seront amenées à coexister de plus en plus. Dans le cadre du projet DECLIC, il a été réalisé une base de données sur la résistance au gel des espèces arborées et arbustives dont l’analyse a pour objectif de prédire l’évolution des forêts compte tenu de ces changements climatiques. Les résultats montrent que les espèces à feuilles persistantes sont plus sensibles au gel que celles à feuilles caduques et que les gymnospermes sont plus résistants que les angiospermes. De plus, la résistance au gel est liée à la position géographique de l’espèce et corrélée non linéairement aux conditions climatiques de sa niche de distribution : ainsi, les espèces les plus résistantes sont associées à des climats plus rudes et à des altitudes et latitudes plus élevées. Le croisement des données de gel et de sécheresse a montré que chez les angiospermes, la résistance au gel exclue la résistance à la sécheresse et inversement. Chez les gymnospermes, en revanche, ces deux résistances peuvent coexister. Puisqu’elles affectent les mêmesprocessus physiologiques, tels que la photosynthèse et la transpiration, et qu’elles ont la même conséquence, à savoir la déshydratation, un compromis entre les résistances à la sécheresse et au gel est envisageable.

The Moroccan Anti-Atlas consists of a several kilometers thick sediment pile accumulated on the northern Gondwana platform since the latest Precambrian (Ediacaran). This study focuses on the Ktaoua Group, early Late Ordovician (Mid-Sandbian to Katian) in age, which records a major and multiphase transgressive/regressive cycle above the shallow marine sandstones of the underlying First Bani Group. In the western Central Anti-Atlas, the Ktaoua Group is formed by offshore shales to coastal sandstones organized in regressive parasequences. Here, high-resolution field-based stratigraphy is used to constrain the shelf architecture and clinoforms geometries within the Ktaoua Group.Whereas the lower part of the Ktaoua Group records parasequences from silty-shale to fine to coarse sandstones with hummocky-cross-stratification (HCS), its upper part oscillates between HCS beds and very coarse sandstones. Ferruginous, condensed horizons usually drape the parasequences. In this study, we investigate the platform geometry through the correlation of the stacking patterns of seventeen stratigraphic logs along an 85 km long, well-exposed cliff. Drone images support the logging and the correlations of the sections by imaging clinoforms geometries. Several decameters of fine to coarse sandstones can be observed to grade laterally into condensed level(s) within a few kilometers, hence evidencing clinoforms pinching out. The visible orientation of the clinoforms along the cliff exposures show a proximal to distal trend from the south-west to the north-east, in agreement with the overall basin geometry. Three clinoforms with distinct geometries and lateral evolution of facies associations are highlighted. The distal part of a clinoform, 15 m in thickness, pinches out onto the top of the underlying First Bani Group within 7 km. The overlying regressive parasequence, approximatively 50 m thick, remains consistent more than 50 km, and is understood as a prograding clinoform. A third clinoform, capped by a prominent sandstone body constantly thicker than 20 m over ca. 20 km, disappears within its last 3.5 km onto the underlying clinoform. This study offers new details on the progradation and regression geometries along a giant platform within a detailed stratigraphic framework.We would like to thank the Pacha and the Gendarmerie Royale of Foum-Zguid, the governor of Tata and the different persons who gave their approval and facilitated the use of the drone in the region of Souss-Massa for their precious help.

Micropollutants (MPs) represent an important environmental and health issue. Identifying their sources and then reducing their discharges is the strategy used in France to fight against water pollution. This is also the approach implemented in the Regard project (Reduction and management of micropollutants in the Bordeaux metropolis). The first phase of the project aimed to carry out a territorial, global and integrated diagnosis combining both chemical and biological analyses of the natural environment and the sewerage network from the discharge points (wastewater treatment plant, separate stormwater overflow, by-pass) to the emission sources (domestic, industrial, hospital and stormwater). In addition, a social characterization of the sources was carried out in order to understand the practices, products and uses at the origin of MP discharges and to identify decisive actions to reduce these discharges. The strengths of this diagnostic assessment are the complementary of various approaches (engineering and social sciences, chemical and biological analyses, wastewater and stormwater studies) and the large number of sampling sites. The second phase of the project was to ensure the implementation of reduction actions to test and evaluate their impacts from the environmental (effectiveness in reducing the quantity, diversity and effect of MPs), social (appropriation and satisfaction of solutions) and economic (to guide public action) points of view. The best results have been achieved with (i) the “water families challenge” action on the domestic source, (ii) mechanical rat control actions, defoaming of tennis courts and grassing of cemeteries for the community source, and (iii) the treatment action of separate stormwater in real conditions on a pilot scale. This feedback on what has been achieved to date should help communities interested to implement such an approach in order to avoid the same “mistakes” and, on the contrary, to directly implement actions that give significant reduction results.; Les micropolluants (MP) représentent un enjeu environnemental et sanitaire important. Identifier leurs sources pour ensuite réduire leurs rejets est la stratégie privilégiée au niveau français pour lutter contre cette pollution. C’est aussi la démarche qui a été mise en oeuvre dans le projet Regard (réduction et gestion des micropolluants sur la métropole bordelaise). La première phase du projet correspondait ainsi à la réalisation d’un diagnostic territorial, global et intégré couplant à la fois des analyses chimiques et biologiques du milieu naturel et du réseau d’assainissement depuis les points de rejets (station de traitement des eaux usées, exutoires pluviaux, by-pass) jusqu’aux sources d’émission (domestique, industrielle, hospitalière et pluviale). En complément, une caractérisation sociale dessources a été faite afin de comprendre les pratiques, les produits et les usages à l’origine des rejets de MP et d’identifier des leviers d’action pour réduire ces rejets. Les points forts de ce diagnostic sont la complémentarité des approches (sciences de l’ingénieur et sciences sociales, analyses chimiques et biologiques, étude des eaux usées et pluviales) et le nombre important de sites d’étude. La seconde phase du projet correspondait à la mise en oeuvre d’actions de réduction pour les tester et les évaluer du point de vue environnemental (efficacité pour réduire la quantité, la diversité et l’effet des MP), social (appropriation et satisfaction vis-à-vis des solutions) et économique (aide à l’orientation de l’action publique). Les actions ayant eu les meilleurs résultats sont (i) l’action « Familles EAU Défi » sur la source domestique, (ii) les actions de dératisation mécanique, de démoussage des terrains de tennis et d’enherbement des cimetières pour la source collectivité et (iii) l’action de traitement des eaux pluviales strictes en conditions réelles à l’échelle d’un pilote. Le présent retour d’expérience sur ce qui a été fait doit aider les collectivités qui souhaiteraient effectuer une telle démarche à ne pas commettre les mêmes « erreurs » et, au contraire, à mettre en oeuvre directement les actions qui donnent des résultats satisfaisants.

National audience; Ces milieux aquatiques fournissent de nombreux services écosystémiques, en assurant des fonctions de support (production primaire, biodiversité), de régulation(épuration des nutriments, régulation des flux hydriques), d’approvisionnement (eau potable, irrigation, énergie) et socio-culturels (loisir, tourisme). Souvent perçusà tort comme immuables, stables et en dehors de toute pression, les plans d’eau font l’objet de multiples usages anthropiques, impactant leur fonctionnement. Lechangement climatique en cours ne fait qu’exacerber ces impacts et accélérer la dégradation des milieux ; à l’échelle régionale, ses effets restent encore à évaluer. Dans cet ouvrage, nous avons souhaité illustrer, de la manière la plus large possible, la variété des systèmes lentiques présents en Nouvelle-Aquitaine,ainsi que les lacunes de connaissance que diverses études mettent en évidence. Le but de cet ouvrage est d’apporter des éclairages scientifiques pourl’aide à la décision et aux choix politiques, et d’accompagner l’appropriation citoyenne des connaissances. Notre souhait ultime serait que ces lieuxemblématiques, source de bien-être et de services, puissent continuer à recouvrir leurs rôles fonctionnels dans le futur.

International audience; During Cambrian-Ordovician times (542-444 Ma), the Anti-Atlas (Southern Morocco) was part of the Gondwana supercontinent and drifted from mid- to subpolar latitudes. The area was part of a shallow marine platform on the so-called northern passive margin of the continent. The stratigraphic succession records a long-term flooding of the platform from the Cambrian to the Silurian. Above Lower Cambrian fluvial to estuarine deposits, an essentially shallow-marine succession (from offshore shales to tidal sandstones) is punctuated by major flooding events in the Middle Cambrian, the lowermost Ordovician, the middle Ordovician and the lower Upper Ordovician. A superimposed eustatic sea-level drop due to the Late Ordovician glaciation marks the last transgressive-regressive cycle that includes the Ktaoua group (mid-Sandbian to Upper Katian) and the glaciation-related Second Bani Group (Hirnantian).In spite of well-known stratigraphy, details of the depositional processes, the overall geometry of the clinoforms (shelf vs. ramp) and resulting stacking patterns of the high-frequency units remain poorly understood in the platform domain. Here, we present a stratigraphic correlation made through a field-based logging of seven sections along a 50 km long, well-exposed cliff located in the Central Anti-Atlas. The Ktaoua to Second Bani groups, part of the Jbel Bani Mountain, are investigated between the villages of Tissint and Foum Zguid. The Ktaoua succession is dominated by high-order regressive parasequences grading from shales into fine to coarse-grained bioturbated sandstones, presenting paraconformable contacts. Incursions of sandstones showing hummocky-cross-stratifications (HCS) are common and considered to represent offshore-transition storm deposits. In the Second Bani Group, which includes glacially-related depositional facies (diamictites), fine to coarse-grained sandstones are dominant as well, though HCS are virtually absent. In the study area, the upper Second Bani Group forms an unconformable unit, severly truncating the Ktaoua succession and emphasizing a regressive sequence initiated within the Ktaoua deposition.These archives enable to constrain the basin geometry in the Upper Ordovician. Indeed, whereas offshore shales in the region of Zagora (Central Anti-Atlas) characterize the depocenter of the basin (eastward from the study area), the studied succession is surrounded by a belt of coarser-grained deposits to the north-east (Alnif, Eastern Anti-Atlas) and west (Tissint/Foum Zguid, Western Central Anti-Atlas). The stratigraphic correlation of the Ktaoua parasequences will be used to reconstruct the orientation, direction, and dip of platform clinoforms, which will allow to dissociate a scheme based on chronostratigraphic units from the usual lithostratigraphy. Besides, we aim to further characterize the geometry, shape, and stratigraphic position of HCS bodies in order to advance our understanding of the setting (e.g., paleobathymetry, position relative to regressive vs. transgressive trends) and hydrodynamic processes generating sandstones bodied with prevailing HCS beds.

National audience; L’objectif du bulletin de situation hydrogéologique (BSH) des nappes est de mettre à la disposition des acteurs de l’eau, un bilan synthétique sur l’évolution mensuelle des ressources en eau souterraine en France. Il est constitué de cartes et de commentaires décrivant la tendance d’évolution du niveau d’une nappe par rapport au mois précédent (stable, à la hausse ou à la baisse) et son état de remplissage (7 niveaux statistiques allant de très bas à très hauts). A ce jour, 259 indicateurs ponctuels (piézomètres) et 31 indicateurs globaux (combinaison de 2 à 20 indicateurs ponctuels pour caractériser un secteur géographique) permettent de préciser, chacun à leur échelle, ces deux informations (tendance-remplissage) qui sont représentées grâce au calcul de l’Indicateur Piézométrique Standardisé (IPS). Cet outil, mis en place pour la réalisation du BSH, est intégré au portail national d’accès aux données sur les eaux souterraines ADES.La collecte et la mise à disposition des données dans ADES se fait à fréquence bimensuelle. Néanmoins, la technologie GPRS, déployée au droit de 1400 ouvrages de surveillance du réseau piézométrique national géré par le BRGM, permet désormais de proposer une mise à disposition quotidienne des données piézométriques. Une actualisation du BSH permet ainsi de suivre quotidiennement l’état des ressources et d’identifier les secteurs en tension quantitative.Dans un contexte de changement climatique avéré sur la ressource en eau, les gestionnaires/utilisateurs de l’eau souhaitent bénéficier d’informations en temps réel sur l’évolution des nappes et d’informations prédictives quant à la disponibilité de la ressource pour les semaines et mois futurs.Le BRGM a développé un outil appelé « MétéEAU des nappes » qui offre, via un site internet, un ensemble de services permettant le suivi du comportement actuel et futur des aquifères. Il est possible, pour les points de surveillance actuellement proposés (et associés à un modèle global Gardénia-Tempo), de visualiser les mesures les plus récemment acquises et issues du réseau piézométrique national. Ces données sont visualisables sous forme de chroniques issues de travaux de modélisation et de prévision des niveaux des nappes en basses eaux ou en hautes eaux. Ces données prévisionnelles, proposées pour une période de 6 mois, sont comparées à des seuils piézométriques « sécheresse » issus des arrêtés préfectoraux de restriction d’usage en vigueur sur la période. D’autres seuils de gestion peuvent également être définis (IPS, niveaux historiques, risque de dénoyage de pompe…). Des données météorologiques, hydrologiques et piézométriques sont mises à disposition, en quasi temps réel, et en format interopérable sur 10 sites représentatifs de France métropolitaine (sélection selon la problématique ayant motivé la mise en place d’un modèle et leur contexte hydrogéologique).Récemment, le BRGM a inventorié près de 550 modèles globaux, mis en œuvre sur 350 piézomètres et sources dont 75 sont utilisés comme indicateurs ponctuels dans le cadre du BSH. Dans le cadre de futurs partenariats, les informations associées à ces modèles pourraient être actualisées puis exposées dans le site internet. Le BSH actuel évoluerait ainsi vers un BSH prévisionnel permettant une meilleure gestion de situations hydrogéologiques extrêmes.

International audience; Le principal site de production d’eau potable via des eaux souterraines d’Eau du Morbihan est situé à Beignon, dans le Nord-Est du Morbihan [A. Le Gal et al., 2015]. Les recherches d’eau réalisées ont permis de mettre en service en 2011 trois forages (FE3, FE4 et FE7), pour un débit total de 125 m3/h. Ces forages sont situés à proximité d’un cours d’eau, l’Aff, affecté régulièrement par des assecs en étiage, au droit des forages mais également sur plusieurs kilomètres en amont. Leur profondeur varie de 97 m à 150 m.Du point de vue géologique, le site est implanté à l’extrémité Ouest des synclinaux paléozoïques du Sud de Rennes, sur les Schistes rouges de Pont Réan, d’âge Paléozoïque. Ces schistes recouvrent les Schistes briovériens, qui affleurent plus au Sud. Les schistes rouges sont surmontés par les Grès armoricains. L’Aff a un cours sinueux, en lien avec les nombreuses failles du secteur (orientation principale N150). Les 3 forages captent en profondeur l’aquifère des Schistes briovériens fracturés, sous recouvrement des Schistes rouges de Pont Réan (zone cimentée, non crépinée).A la demande d’Eau du Morbihan et des Directions Départementales des Territoires et de la Mer du Morbihan et d’Ille-et-Vilaine, le BRGM a réalisé en 2014-2015 des études complémentaires afin d’évaluer l’incidence de l’exploitation des 3 forages sur le débit de l’Aff [Rapport BRGM/RP-64225-FR]. Elles ont confirmé la complexité de ce site : signature atypique en strontium pour un aquifère briovérien, pertes du cours d’eau inhabituelles en zone de socle, débits souterrains exceptionnellement élevés en zone de socle, aquifère a priori très compartimenté.Compte-tenu de la complexité de ce site stratégique pour l’alimentation en eau potable du secteur, Eau du Morbihan et le BRGM ont cofinancé un projet pour améliorer la compréhension du fonctionnement hydrogéologique du site (avec subvention de l’Agence de l’Eau Loire-Bretagne).Les objectifs étaient les suivants : (i) améliorer la connaissance de l’aquifère de socle complexe considéré, (ii) établir son schéma de fonctionnement hydrogéologique et géochimique, (iii) évaluer l’impact quantitatif des prélèvements dans les 3 forages sur la rivière de l’Aff, (iv) gérer de façon durable les prélèvements au niveau des 3 forages pour assurer la distribution d’eau potable, préserver la ressource quantitativement et qualitativement, et limiter l’impact de l’exploitation sur le cours d’eau.Pour répondre à ces objectifs, la réalisation de ce projet (2017-2021) s’est appuyée sur une approche scientifique pluri-disciplinaire : hydrogéologie (synthèse bibliographique, monitorings, slug-tests, diagraphies, divers essais de pompage, nouveaux forages), géophysique (panneaux électriques), géologie (investigations de terrain, analyse des cuttings des ouvrages), hydrologie (installation de stations de jaugeage en rivière, équipements, courbes de tarage), géochimie (analyses physico-chimiques et isotopiques, en hautes eaux, en basses eaux, et en pompage)…

International audience; Foams can be used to remediate aquifer pollution due to industrial leaks. However, when in contact with oily pollutants, foams may collapse and thus have a very limited life-time. A suitable formulation of biodegradable foam that resists oil contact is therefore needed. Hence, the ability of xanthan polymer and silica colloidal particles to stabilise foam against oil was investigated. Their performance in terms of stabilisation was evaluated via foam generation experiments in columns of porous medium, conducted with and without oil. The results show that the addition of xanthan polymer led to an increase in the viscosity of the solution, which thwarted the formation of foam. It did not improve the resistance of foam to oil, but increased altogether the resistance factor up to more than twice the original value. Concerning silica particles, it was demonstrated that they both noticeably increased resistance factor and moderately stabilised foam against oil by 20% at optimum concentration. As such, this study presents a new way to reinforce foam against oil for soil remediation issues.

International audience; À la fin des années 60, l'idée d'une glaciation d'âge Ordovicien supérieur s'impose à la communauté des Sciences de la Terre. Des indices concordants, tout d'abord identifiés de la Mauritanie au Tchad, laissent imaginer une glaciation d'envergure comparable à l'actuel inlandsis antarctique qui aurait essentiellement touché l'Afrique du Nord et de l'Ouest alors positionnée aux hautes latitudes australes. Depuis, des dépôts glaciaires de même âge ont été reconnus plus à l'est, jusqu'en Iran et en Oman, vers le sud, jusqu'au cap de Bonne-Espérance, et vers l'ouest, sur une grande partie du continent sud-américain. Au nord, en Europe, des dépôts à galets lâchés par des glaces dérivantes sont connus du Portugal à la Bulgarie, en passant par la France (Bretagne, Normandie, Corse) ; des icebergs circulaient jusqu'en Pologne par de-là le paléo-océan Rhéique. C'est en fait l'ensemble du Gondwana occidental (Afrique jointe à l'Amérique du Sud) qui fut affecté par cette glaciation (fig. 1). Au Maroc, les séries sédimentaires de l'Ordovicien de l'Anti-Atlas (au sud) mais aussi de la Meseta (au nord) recèlent des archives glaciaires tout à fait exceptionnelles. On doit leur mise en évidence à J. Destombes, qui publie en 1968 deux courts articles : l'un démontre que les glaciers issus de l'actuel Sahara s'écoulaient jusqu'au Maroc ; l'autre apporte une donnée fondamentale quant à l'âge de cette glaciation en précisant l'âge hirnantien de son maximum d'extension, soit l'Ordovicien tout à fait terminal (âge aujourd'hui estimé autour de 444-445 millions d'années). La poursuite du programme de cartographie géologique de l'Anti-Atlas aboutira à la synthèse de 1985 qui inspira et reste encore aujourd'hui la base de nombreux programmes de recherche dédiés au Paléozoïque du Maroc en général (Voir Razin et al., ce numéro), et à l'Hirnantien glaciaire en particulier.

International audience; Previous drilling through submerged fossil coral reefs has greatly improved our understanding of the general pattern of sea-level change since the Last Glacial Maximum, however, how reefs responded to these changes remains uncertain. Here we document the evolution of the Great Barrier Reef (GBR), the world’s largest reef system, to major, abrupt environmental changes over the past 30 thousand years based on comprehensive sedimentological, biological and geochronological records from fossil reef cores. We show that reefs migrated seaward as sea level fell to its lowest level during the most recent glaciation (~20.5–20.7 thousand years ago (ka)), then landward as the shelf flooded and ocean temperatures increased during the subsequent deglacial period (~20–10 ka). Growth was interrupted by five reef-death events caused by subaerial exposure or sea-level rise outpacing reef growth. Around 10 ka, the reef drowned as the sea level continued to rise, flooding more of the shelf and causing a higher sediment flux. The GBR’s capacity for rapid lateral migration at rates of 0.2–1.5 m yr$^{−1}$ (and the ability to recruit locally) suggest that, as an ecosystem, the GBR has been more resilient to past sea-level and temperature fluctuations than previously thought, but it has been highly sensitive to increased sediment input over centennial–millennial timescales.

International audience; La caractérisation de la pollution du milieu souterrain d’un site est un enjeu essentiel pour définir les actions de remédiation et atteindre les objectifs associés. Parmi les verrous récurrents à cette caractérisation, se situent la complexité des sites, les hétérogénéités géologiques des sols, les grandes différences de comportement et de mobilité des polluants d’intérêts. La compréhension de la distribution des polluants et des contextes physiques dans lesquels ils se situent représente une clé du succès d’une opération de remédiation.La caractérisation des pollutions, par l’intermédiaire d’un prélèvement classique d’eaux souterraines réalisé dans un piézomètre, fournit généralement une information trop partielle pour permettre d’établir un schéma conceptuel de qualité des milieux complexes. Dans pareil cas, des prélèvements multi niveaux et l’acquisition de données complémentaires aux données de qualité chimiques des eaux sont indispensables.Cette étude organise un atelier participatif pour tester différents outils innovants de caractérisation détaillée des matrices souterraines :Mesures de flux de nappe (sens, vitesse …),Mesures multiniveaux de la matrice eau (concentrations, flux…).Les résultats attendus portent sur des connaissances partagées des périmètres d’utilisation de ces outils (typologies de site, géologie, hydrogéologie, contaminants…), des conditions opérationnelles de leur mise en œuvre (conditions d’accès à la technique, facilités d’utilisation, compétences nécessaires, coûts associés, …), de leurs performances techniques (précisions, incertitudes, quantifications, …), de leurs limites (selon les différents contextes de sites…).Cette comparaison doit favoriser l’appropriation d’outils innovants (français et étrangers) pour une caractérisation détaillée de sites pollués (D-L-NAPL), permettant de mieux comprendre les dynamiques et le fonctionnement des systèmes. Elle pourrait permettre de proposer des schémas conceptuels plus précis pour une meilleure connaissance des transferts et une meilleure conception des opérations de remédiation.

International audience

International audience; The Pyrenees, at the border between France and Spain constitute a typical example of an intraplate orogen. They result from the closure and inversion of Albian rift basins during the upper Cretaceous to Eocene times. The Albian basins, result from the hyperextension of continental crust which sometimes led to the exhumation of subcontinental mantle and locally accompanied by a High-Temperature and Low-Pressure metamorphism. This metamorphic zone is currently located along the eastern half part of the chain in a narrow and highly deformed band known as Internal Metamorphic Zone (IMZ). The deformation observed in the IMZ is too intense to estimate the initial geometry of the former Albian basins. In this study, we used a new approach based on thermal data acquired by Raman Spectroscopy on Carbonaceous Material. We thus constrain the original dimensions and structure of the former basin. We determined 7 thermal paleogradients, across the only preserved rift-basin (Mauleon basin) using 156 Tmax measured on boreholes and field samples. We obtained different paleogradient values increasing from proximal to distal rift domains: ~30-36°C/km for proximal margin 37-45°C/km for necking zone and 57-60°C/km for hyper-extended domain. In addition, the present-day thermal gradient, combined with the paleogradietns allows us to model the evolution of the thermicity from rifting to collision. nterpolating the highest paleogradients, the temperature at the base of the basin reached 600°C. This is identical to temperature measured in the IZM. This thermal calibration of preserved Mauleon basin allows then to restore the geometry of the stretched IZM basin.

International audience

International audience; Authigenic clay coats (mostly Fe-rich chlorite coats) affect sandstone reservoir qualities by inhibiting quartz overgrowth during burial diagenesis, preserving both porosity and permeability. It is still unclear what initial mineralogical assemblages and initial sedimentation conditions produce chloritized sandstone reservoirs, which is important for sandstone reservoir quality prediction. For this purpose, better link facies with chlorite coat occurences could be useful. To address these questions, sedimentological, petrographical and mineralogical analyses were carried out from sand and sandstones cores for both a deeply buried Permian estuarine sandstone reservoir (Australia) and the Gironde estuary (France). Comparisons reveal similar sedimentary facies and vertical facies associations (from a muddy bottom to cross-stratified sandier packages and to a muddy top), indicative of tidal sand bars deposited in a mud-rich estuary. These criteria can be useful for recognizing tidal deposits when describing cores. X-ray diffraction and Scanning Electron Microscope (SEM) analysis show that detrital clay minerals are composed of illite, smectite, kaolinite and chlorite while clay assemblage differs in the Permian reservoir with dickite or an illite-rich illite/smectite mixed layer (I/S). Coats are either composed of detrital clays minerals (Gironde) or Fe-rich chlorite crystals (Permian). Transformations of detrital clays into other clay minerals (such as berthierine, precursor to Fe-rich chlorite) during eogenesis can initiate well-crystallized Fe-rich chlorite formation during burial diagenesis. Detrital minerals and detrital clay grain coats observed in the Gironde estuary could be the prerequisite initial conditions for generating authigenic Fe-rich chlorite coats in estuarine sandstones during burial. This is partly due to the initial clay fraction content of 15-20%, part of which forms detrital clay grain coats. Our main conclusion shows that facies from the middle to the upper tidal sand bar at the top of the transgressive cycle were probably uncemented during burial, and might be good candidates during reservoir exploration.

International audience; Deglacial sedimentary sequences recording the decay and final demise of ice sheets result from intricate interactions between the pattern of ice margin retreat, inherited basin physiography and relative sea-level (RSL) changes. A specific emphasis is here given to the glacio-isostatic adjustment (GIA), which may force postglacial local RSL fall in spite of concomitant glacio-eustatic rise. In this contribution, we characterize a Quaternary deglacial succession emplaced in such a setting, subsequently used as an analogue to interpret an end-Ordovician deglacial record. The Quaternary deglacial succession, tens of metres thick, formed under condition of RSL fall forced by the GIA in c. 10 000 years in the aftermath of the deglaciation. This sedimentary succession consists of a lower, fining-upward sequence representing the backstepping of ice-contact depocentres following the retreat of the ice margin, and an upper, coarsening-upward sequence that relates to the subsequent progradation of a glaciofluvial delta system. A very similar stratigraphic stacking pattern characterizes the Ordovician analogue, suggesting a comparable deglacial sequence. By analogy with the Quaternary succession, this ancient deglacial record would have hence been emplaced under conditions of RSL fall forced by the GIA. Moreover, it must only represent a very short time interval that could be viewed as virtually instantaneous regarding the Late Ordovician glaciation. Such a vision is at odds with commonly accepted interpretations for such successions.

International audience

In urban areas, information concerning very high resolution land cover and especially material maps are necessary for several city modelling or monitoring applications. That is to say, knowledge concerning the roofing materials or the different kinds of ground areas is required. Airborne remote sensing techniques appear to be convenient for providing such information at a large scale. However, results obtained using most traditional processing methods based on usual red-green-blue-near infrared multispectral images remain limited for such applications. A possible way to improve classification results is to enhance the imagery spectral resolution using superspectral or hyperspectral sensors. In this study, it is intended to design a superspectral sensor dedicated to urban materials classification and this work particularly focused on the selection of the optimal spectral band subsets for such sensor. First, reflectance spectral signatures of urban materials were collected from 7 spectral libraires. Then, spectral optimization was performed using this data set. The band selection workflow included two steps, optimising first the number of spectral bands using an incremental method and then examining several possible optimised band subsets using a stochastic algorithm. The same wrapper relevance criterion relying on a confidence measure of Random Forests classifier was used at both steps. To cope with the limited number of available spectra for several classes, additional synthetic spectra were generated from the collection of reference spectra: intra-class variability was simulated by multiplying reference spectra by a random coefficient. At the end, selected band subsets were evaluated considering the classification quality reached using a rbf svm classifier. It was confirmed that a limited band subset was sufficient to classify common urban materials. The important contribution of bands from the Short Wave Infra-Red (SWIR) spectral domain (1000–2400 nm) to material classification was also shown.