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International audience; The database for hydrological observatories (BDOH) is an efficient tool for storage which allows the combination of water discharge data, suspended particulate matter (SPM) and particulate contaminants concentrations, produced thought a same observatory network, to calculate time series fluxes. This application is used in the Rhone Sediment Observatory (OSR) program to estimate SPM and their associated contaminants fluxes along the Rhone River and its main tributaries. However, incomplete time series need to be filled prior to computation in BDOH. Hence, a sensitivity test was run to evaluate the effect of different estimation methods of SPM concentration and particulate mercury time series on final instantaneous and accumulated fluxes on the Rhone River at the two main stations of the OSR network (Jons and Arles). The results demonstrate that the differences between SPM and particulate mercury annual fluxes assessed with different estimation methods are less than 5%. However, at monthly scale, estimation methods can create higher differences (26-51%). In the future, these preliminary results will be completed with the estimation of the uncertainties associated with particle flux measurements.; La Base de Données pour les Observatoires en Hydrologie (BDOH) est un outil de bancarisation qui permet de combiner les mesures de débit, de matières en suspension (MES) et de contaminants particulaires issues d'un même réseau de stations pour calculer des chroniques de flux instantanés et cumulés. Cette application est utilisée dans le cadre de l'Observatoire des Sédiments du Rhône (OSR) pour estimer les flux de MES et de contaminants associés (Hg, PCB,...) en transit dans le Rhône et ses principaux affluents. Cependant, avant le calcul de ces chroniques, les données mères lacunaires doivent être reconstituées. Un test de sensibilité a été mené afin d'évaluer l'impact de différentes méthodes d'estimation des chroniques de concentrations en MES et en Hg particulaire sur les calculs de flux instantanés et cumulés dans le Rhône aux deux stations principales de l'OSR (Jons et Arles). Les résultats montrent que, quelle que soit la méthode d'estimation utilisée, les flux annuels de MES et de Hg particulaire ne diffèrent pas plus de 5 %. A l'échelle mensuelle, en revanche, les différentes méthodes génèrent des variabilités plus élevées (26-51 %). En perspective, ces premiers résultats seront complétés par l'évaluation des incertitudes quantitatives sur les calculs de flux particulaires.

International audience; Pharmaceutical wastewaters are usually characterized by a complex mixture of active substances and metabolites with variable characteristics and composition throughout the year. Accordingly, assessing the efficiency of pharmaceutical industry treatment plants and the resulting decrease in effluent ecotoxicity and ecological risk throughout the treatment process remains very challenging. Microbial biofilms have been proven to be early warning natural assemblages to detect acute and long-term effects produced by toxic substances, including pharmaceuticals. Being composed of both autotrophic and heterotrophic microorganisms exhibiting a large range of sensitivity to many toxicants, biofilms are thus relevant models to assess ecotoxicological risks of effluents by studying effects on microbial structure, diversity and functions. In this context, in collaboration with the pharmaceutical firm SANOFI, we installed a pilot system, connected to the wastewater treatment plant of a SANOFI production factory, to evaluate, throughout the treatment steps, the decrease in chronic and acute toxicity of pharmaceutical production effluents for natural biofilms. The system consists of five artificial outdoor channels, each sub-divided into three compartments to ensure replication, continuously filled with wastewater collected after secondary, tertiary and quaternary treatments, respectively, as well as with stream water collected at the immediate upstream and downstream from the discharge. The chronic and acute toxicity of effluents on natural biofilms will be evaluated by combining structural and functional analysis as well as a pollution community tolerance (PICT) approach using pharmaceutical mixtures directly extracted from passive samplers (Polar Organic Chemical Integrative Samplers, POCIS) immersed for several weeks in the different channels.

International audience; While many metals are known to accumulate in sediments, knowledge about the resulting ecotoxicological effects on sediment microbial communities is scarce. The present study aimed at evaluating the structural and functional impact of chronic exposure to environmental concentrations of copper (Cu) and arsenic (As), alone or mixed together, on river sediment microbial communities. Natural uncontaminated surface sediments collected in a French River (Ain) were spiked with As and Cu at a nominal concentration of 40 mg/kg and then were exposed for 21 days in laboratory channels with overlying waters. The response of heterotrophic microbial communities to metals was evaluated both in terms of genetic structure (using ARISA analysis) and functional potential (using exo-enzymatic, metabolic and qPCR analyses). A pollution induced community tolerance (PICT) approach was also performed to assess if the exposure led to an increase in the capacity of microbial communities to tolerate metals. Our results showed rapid and marked effects of Cu alone on the structure and the functions of the exposed communities. Chronic Cu exposure also induced an increase in community tolerance to Cu, as observed by PICT measurement using beta-glucosidase activity. In contrast, the effects of As were mostly undetectable. Under mixture exposure (Cu+As), the effects were similar or higher than those provoked by Cu alone, depending on the measured parameter. Altogether those findings reveal that metals accumulation in sediments can impact exposed microbial communities thus affecting their functional role in aquatic ecosystems.

International audience; Sediments play a critical role in biogeochemical cycling and in the maintenance of the biodiversity. They are natural sinks for many contaminants which can accumulate over time and impact exposed communities, thereby disturbing the functioning of aquatic ecosystems. However, knowledge about the functional effects of contaminants on benthic communities is scarce and there is a need of ecosystem functioning indicators of ecotoxicological impacts. In the present microcosm study, we assessed the individual and combined effects of Cu and As (40 mg kg dw-1 each, 21 days of exposure) on the capacity of natural micro- and macro-organism communities from an uncontaminated river sediment to consume and decompose particulate organic matter using the bait lamina method (ISO 18311) as well as artificial tablets consisting of cellulose, bran flakes and active coal embedded in an agar matrix. The sediment toxicity was also evaluated using the standardized ostracod toxicity test (ISO 14371:2012). The two tested substrates (i.e. bait lamina and artificial tablets) showed similar results with low effects of As on feeding activity and organic matter breakdown whereas Cu demonstrated a strongest functional effect. When the two metals were combined, a total functional inhibition was observed, whatever the kind of substrate. The ostracod toxicity test also showed high toxicity of Cu-spiked and mixture-spiked sediments and low toxicity of As-spiked sediments. Our results highlight the relevance of artificial organic matter substrates to assess the functional effects of contaminants on sediment micro- and macro-organism communities, opening new perspectives to assess the functional integrity of contaminated sediments.

International audience; In the last decade, omics tools dedicated to microbial communities have been developed to characterize the functional groups of those communities and better understand microbial response to contamination. Most of those tools focused on heterotrophic and fungal communities while omics application dedicated to microalgae and diatoms are mostly restrained to diversity assessment (e.g. based on 18S rRNA or rbcL genes). In this study, the possibility of studying gene expression in autotrophic river biofilm communities was explored and we present the proof of concept for a Functional Gene Array (FGA), based on consensus sequences from genes of key physiological processes. Indeed, microarrays offer a comprehensive tool for system-wide analysis of community functioning based on the simultaneous detection of the activity of thousands of genes. The FGA designed in this study include 83 functional genes chosen to reflect several essential biochemical pathways and specific stress response pathways of microalgae. Probes of these genes were designed from consensus sequences from up to 6 microalgal species (diatoms and chlorophytes). Furthermore, species-specific probes were included resulting in 1554 unique oligonucleotide probes for 83 different genes. RNA extracted from Chlamydomonas reinhardtii, Scenedesmus vacuolatus and multi-species biofilms was then used to test different hybridisation conditions. Signal intensity was affected by sequence divergence but results showed that a hybridisation temperature of 55ºC allowed a good compromise between cross-hybridisation and specificity. Due to the reduced number of probes and available sequence information the designed FGAs is at present particularly useful for ecotoxicological laboratory experiments performed with biofilm communities.

International audience; In the context of the European Water Framework Directive (WFD, 2000/60/EC), which aims to achieve a good ecological and chemical status for all natural aquatic environments, it is necessary to better quantifying pesticide transfers in agricultural watersheds. Modeling is a relevant tool to study the processes occuring in the fate of pesticides, and identifying sound managing solutions to water contamination. Physically-based and spatially distributed models are particularly useful to represent in detail processes and interactions between the soil surface and subsurface. In particular, they can help to assess the role of landscape elements such as vegetative buffer strips, ditches, ... . The present study aims to test a recently added reactive transport to the coupled surface water/groundwater 3D model CATHY, in order to represent pesticide transfers at the watershed scale. Contaminant reactions implemented are linear adsorption and degradation (first order kinetics). The model has been successfully validated on laboratory data and submitted to a sensitivity analysis as a further step of validation. In this study, we tested the model on field conditions, simulating a 150 m x 40 m hillslope in the Morcille catchment (Beaujolais, France). The hillslope is predominantly covered with a chemically weeded vineyard crossed by 4 very shallow ditches gathering the runoff towards a concrete channel. The flow coming from the vineyard plot in then conducted on a 25 m long vegetative buffer strip. The site is instrumented with piezometers, lysimeters, flow and solute concentration measurement devices. Real field conditions makes the model's application more difficult because of the complexity in representing the interactive processes in a large domain, combined to uncertainty on input parameters that is important in field experiments. However, such challenging modeling allows a more comprehensive understanding of solute transfers and gives some keys to evaluate the efficiency of mitigation elements of the landscape.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; International audience; The interest of epigenetic regulation is becoming increasingly important in ecotoxicology. Among epigenetic marks, DNA methylation could be a biomarker of interest. The aim of this study is to investigate the measurement of genomic DNA methylation level as a possible stress biomarker in the ecologically relevant freshwater species Gammarus fossarum.

International audience; In the past decades, an increasing number of anthropogenic contaminants such as pesticides, antibiotics or drug residues has reached the aquatic ecosystem, leading to chronic chemical perturbations. While improvements in chemical analyses allow detecting a large diversity of micro-pollutants at low chemical concentrations, biological analyses are still required to estimate the effects of contaminants in the environment. In particular, the PICT (Pollution Induced Community Tolerance) approach allows detecting chronic exposure to specific contaminants based on microbial communities’ adaptation capacity. Thus, an increase in microbial tolerance to a pollutant is likely to reflect the adaptative response of microbial communities to such a perturbation. Acute toxicity tests performed in laboratory on natural communities can reveal this tolerance acquisition and point to a direct link between tolerance and pollutant exposure. For instance, Pesce et al. 2016 highlighted a decrease in microbial community tolerance to the herbicide diuron, in a freshwater stream, following diuron ban. The PICT approach provides information on both environmental contamination and ecological effect and thus can be used to reveal chronic effects of an environment contamination as well as to follow microbial response after a perturbation. However, currently toxicity tests on natural microbial communities are time-consuming which limits the number of contaminants or sites tested simultaneously. In this context, the aim of this work was to optimize toxicity tests performed on periphytic communities (e.g. time reduction, process miniaturization) to eventually provide a battery of toxicity tests to detect contaminant effects on community tolerance. Furthermore, those improved tests were applied, during a monitoring program, on a freshwater stream impacted by pesticides to reveal differences in exposure. The optimization of toxicity tests on microbial communities will improve the use of PICT approach in environmental assessment.

International audience; Several types of passive samplers have been developed for the time-integrative monitoring of various organic contaminants in the aquatic environment. The passive SBSE (p-SBSE) has been recently demonstrated to be a suitable passive sampler for pesticides monitoring in agricultural watersheds. Nevertheless, for the determination of time-weighted average (TWA) concentrations, a calibration of the passive samplers under controlled conditions has to be performed prior to field exposure in order to determine for each pesticides accumulation kinetics and sampling rates (Rs). Many calibration systems have been described in the literature, but we could not find any comparison of these experimental systems for a same passive sampler and tested compounds. The aim of this study was to test two different laboratory experimental systems (continuous flow and static mode) for the calibration of p-SBSE for 16 pesticides with a wide range of physico-chemical properties (log Kow 2.2 – 5.1). We evaluated the performances of both systems in terms of consumption of water and pesticides, and stability of flow rate, temperature and pesticides concentration during the calibration experiments. The continuous flow calibration was performed in 15 glass channels (3 L each and a triplicate of p-SBSE per channel) and was based on a constant supply of water contaminated with the studied pesticides. The nominal concentrations ranged from 0.2 to 40 µg/L depending on the pesticides. The static mode calibration consisted in placing the passive samplers (up to 24 p-SBSE) in a 30 L-stainless steel tank containing spiked silicone sheets (8 sheets used), as a diffuse source of pesticides in order to generate a constant water contamination during the calibration period. The nominal concentrations of pesticides ranged from 0.1 to 150 µg/L. We performed the calibration at 20°C during 7 days for both experimental systems. The flow velocity was 2.5 cm.s-1 in the continuous flow calibration, and 10 cm.s-1 in the static mode calibration. For both systems, the temperature and the water flow velocity were stable during the calibration (20°C ± 1 for temperature, and RSD lower than 14% (n=240) for flow velocity measurements). The main advantage of the continuous flow calibration system is that the hydrodynamic conditions are close to the in situ conditions. However, it requires huge volumes of water (2000 L) and a large amount of pesticides (3.5 g) for spiked water renewal in order to maintain hydrophobic pesticide concentrations stable. Moreover, the system is relatively complex to operate due to the large number of pumps that need to be accurately calibrated. On the contrary, the static mode calibration system allows a limited consumption of water (30 L) and pesticides (0.1 g) as water renewal was not needed. This system is easy to use and stable contaminant concentrations in water can simply be maintained. However, it requires a previous step for spiking the silicone sheets which implies to know the exchange kinetics between silicone sheet, water and passive samplers before calibration. Both systems enabled to obtain curvilinear sorption profiles for 16 pesticides that were used for the determination of Rs. For hydrophilic compounds, the calculated Rs are similar with both systems, whereas for hydrophobic pesticides, the Rs obtained with the batch mode calibration system are generally greater, which can be relied to the difference of flow velocity between the two systems.

International audience; The degree of pollution of waterbodies is traditionally appraised by micropollutants research and quantification applied in sediment or in water. While this chemical approach can determine contamination of the targeted compounds in waterbodies, it is inadequate for assessing the bioavailability of chemical substances and toxic impact of aquatic environments (characterized by complex mixture of pollutants) which are currently proposed as complementary analysis. Because of the need of such diagnosis tools for public and private managers, substantial efforts have been made over the last 30 years to develop and apply innovating biological approaches for risk assessment. In this context, this presentation focuses on using a crustacean model, the freshwater amphipod Gammarus fossarum, to assess chemical contamination and toxicity. Our approach of active biomonitoring, based on calibration of “control” individuals (size, sex, population,…) which were exposed during 7 days directly in waterbodies (by caging methodology), is an integrative and relevant approach for field experiments. To demonstrate it, we will show how in situ bioassays bring complementary information to public and private managers in illustrating by various cases of study: waste water treatment plant, storm pillway, dam draining as well as industrial sites. During these field experiments, we finally assessed 1- level of bioavailability contamination for metallic and organic compounds in exposed gammarids and 2- ecotoxicological effects on global parameters (survival, feeding rate, reprotoxicity) and on specific parameters (acetylcholinesterase activity, endocrine disruption). For a reliable data interpretation, we proposed threshold values for bioaccumulated concentrations and biological responses. The general purpose is to highlight the operational, cost-effective and reliable character of active monitoring using gammarids for a large scale deployment in waterbodies.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; International audience; Despite the importance of invertebrates in aquatic systems, we lack specific biomarkers to assess the effects of endocrine disruption (ED) on these animals. This can be attributed to a poor knowledge of their endocrine systems and to the absence of genomic data for non-model species. The development of relevant tools for hazard assessment of ED is currently a challenge for crustacean species used in aquatic ecotoxicology. Our research teams have conducted a “proteogenomic” approach to generate a large transcriptomic and proteomic dataset for the amphipod crustacean Gammarus fossarum, a sentinel species used widely in aquatic ecotoxicology in Europe. However, among the 2257 MS-certified proteins obtained with this approach, key proteins involved in hormonal regulation that could be potential candidates for endocrine disruption biomarkers were not identified. Therefore, the aim of this study was to identify, in G. fossarum, some key players involved in the endocrine regulation of crustaceans/amphipods in order to propose candidate biomarkers of endocrine disruptions in this species. For this, we first established a list of candidate genes known to play an essential role in hormonal systems of crustaceans and insects: nuclear hormone receptors, other regulatory genes, enzymes of the hormone metabolism and hormone-regulated genes. Using sequence similarity and phylogenetic analyses, we identified similar sequences of three candidate genes in our transcriptomic G. fossarum database: the nuclear receptors RXR and E75, and the regulator broad-complex. The three genes were cloned in order to obtain reliable nucleotide sequences and primers for the subsequent expression studies. Their functional validation and relevance as biomarkers was then performed by studying gene expression during the female reproductive cycle, and after laboratory exposure to model ED chemical compounds (pyriproxyfen and tebufenozide).

International audience; The degree of pollution of waterbodies is traditionally appraised by micropollutants research and quantification applied in sediment or in water. While this chemical approach can determine contamination of the targeted compounds in waterbodies, it is inadequate for assessing the bioavailability of chemical substances and toxic impact of aquatic environments (characterized by complex mixture of pollutants) which are currently proposed as complementary analysis. Because of the need of such diagnosis tools for public and private managers, substantial efforts have been made over the last 30 years to develop and apply innovating biological approaches for risk assessment. In this context, this presentation focuses on using a crustacean model, the freshwater amphipod Gammarus fossarum, to assess chemical contamination and toxicity. Our approach of active biomonitoring, based on calibration of “control” individuals (size, sex, population,…) which were exposed during 7 days directly in waterbodies (by caging methodology), is an integrative and relevant approach for field experiments. To demonstrate it, we will show how in situ bioassays bring complementary information to public and private managers in illustrating by various cases of study: waste water treatment plant, storm pillway, dam draining as well as industrial sites. During these field experiments, we finally assessed 1- level of bioavailability contamination for metallic and organic compounds in exposed gammarids and 2- ecotoxicological effects on global parameters (survival, feeding rate, reprotoxicity) and on specific parameters (acetylcholinesterase activity, endocrine disruption). For a reliable data interpretation, we proposed threshold values for bioaccumulated concentrations and biological responses. The general purpose is to highlight the operational, cost-effective and reliable character of active monitoring using gammarids for a large scale deployment in waterbodies.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; International audience; Proteomics is becoming popular in ecotoxicology as an approach for the discovery of new candidate biomarkers of environmental contamination. Studies are currently based on the classical proteomic approach, in which proteomes from a control and a contaminated situation are resolved by 2D-PAGE, and proteins differentially expressed are then identified by mass spectrometry. Most of these detected proteins are abundant, usually housekeeping proteins, such as those involved in ATP metabolism and maintenance of the cytoskeletal structure, but rarely specific to a contamination exposure. This drawback is due to the few sequenced genomes in aquatic invertebrates that limit the interpretation of the mass spectra and the identification of proteins, and the low dynamic range of the 2D-PAGE approach. Recent technological advances in highthroughput “omics” methodologies, in which thousands of genes, proteins or metabolites can be assessed simultaneously, provide invaluable molecular information. Shotgun proteomics allows in-depth analysis of whole proteomes if performed with the most recent mass spectrometers. In order to unveil the novel perspectives offered by the latest generation of mass analyzer, we analyzed the performances of the Q-Exactive HF tandem mass spectrometer equipped with an ultra-high field Orbitrap analyzer. The aim of this study was to reconsider the discovery of new candidate biomarkers of exposure to Pyriproxyfen in male gammarids by shotgun proteomics, in the light of the latest generation of tandem mass spectrometer. Males were exposed to two concentrations of the xenobiotic Pyriproxyfen (0.5 and 50 μg/L) during two consecutive spermatogenesis cycles. The number of proteins identified, their abundance and the number of proteins that were modulated by the contamination were used to document the performance of the new.

National audience; Les résultats des expérimentations ex-situ et in-situ sur le gammare réalisés à la station d'épuration de Sophia Antipolis rendent compte de la toxicité des rejets en sortie de traitements secondaire. Des effets toxiques gradués ont été mesurés le long de la ligne de traitement complémentaire, plus prononcés en amont qu'en aval des traitements, et un impact a été observé dans le milieu récepteur.

Benthic ecosystems are important areas both in terms of biodiversity and functioning. They are receiving direct or indirect inputs from the water column or from the watershed and may therefore be accumulating zones for contaminants. Many benthic and epibenthic organisms may be exposed to these substances, with as consequences, disruption of ecological traits and functions at the ecosystem level such as changes in benthic community structure and ecosystem functioning. However, knowledge about the ecotoxicological effects of accumulated contaminants at the benthic community level is scarce. Accordingly, the present study aimed at assessing the functional impact of chronic exposure to environmental concentrations of metals on natural sediment communities. We evaluate the usefulness of assessing/studying feeding activity and organic matter breakdown as endpoints, using two kinds of artificial organic matter substrates.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; National audience; Despite the importance of invertebrates in aquatic systems, we lack specific biomarkers to assess the effects of endocrine disruption (ED) on these animals. This can be attributed to a poor knowledge of their endocrine systems and to the absence of genomic data for non-model species. The development of relevant tools for hazard assessment of ED is currently a challenge for crustacean species used in aquatic ecotoxicology. Our research teams have conducted a “proteogenomic” approach to generate a large transcriptomic and proteomic dataset for the amphipod crustacean Gammarus fossarum, a sentinel species used widely in aquatic ecotoxicology in Europe. However, among the 2257 MS-certified proteins obtained with this approach, key proteins involved in hormonal regulation that could be potential candidates for endocrine disruption biomarkers were not identified. Therefore, the aim of this study was to identify, in G. fossarum, some key players involved in the endocrine regulation of crustaceans/amphipods in order to propose candidate biomarkers of endocrine disruptions in this species. For this, we first established a list of candidate genes known to play an essential role in hormonal systems of crustaceans and insects: nuclear hormone receptors, other regulatory genes, enzymes of the hormone metabolism and hormone-regulated genes. Using sequence similarity and phylogenetic analyses, we identified similar sequences of three candidate genes in our transcriptomic G. fossarum database: the nuclear receptors RXR and E75, and the regulator broad-complex. The three genes were cloned in order to obtain reliable nucleotide sequences and primers for the subsequent expression studies. Their functional validation and relevance as biomarkers was then performed by studying gene expression during the female reproductive cycle, and after laboratory exposure to model ED chemical compounds (pyriproxyfen and tebufenozide).

International audience; During the months of August 1893 and August 2003 two heat waves greatly affected France. This study considers “offline” data assimilation method using the Ensemble Kalman Filter to provide a reanalysis of the two heat waves. The method is here applied for reconstructing the 8-24 August 1893 heat wave in France, using all available daily temperature observations from that period. In order to assess the performance of assimilation methods, the method is used to reconstruct the well-known 3-14 August 2003 heat wave by using (1) all available stations, and (2) the same station density as in August 1893. Results show a spatially coherent view of the heat waves at the national scale as well as a reduced uncertainty compared to initial meteorological reconstructions, thus demonstrating the added value of data assimilation.

International audience; In the context of the European Water Framework Directive (WFD, 2000/60/EC), which aims to achieve a good ecological and chemical status for all natural aquatic environments, tools to help understand and quantify pesticide transfers in agricultural watersheds are necessary. Models which are physically based and spatially distributed can be particularly useful for representing in detail processes and interactions between the soil surface and subsurface and thus to evaluate the management of landscape elements remediation. The present study aims to test and validate a recently added reactive transport to the coupled surface water/groundwater model CATHY, in order to represent pesticide transfers. Contaminant reactions implemented in CATHY for this study are linear adsorption and degradation (first order kinetics). The advection part of the model is solved according to the finite volume method and reactions are computed on volumes using a sequential non-iterative approach. The CATHY model has been tested on laboratory data and with a Morris sensitivity analysis and is applied now in real field conditions, on a vegetative buffer strip monitored by Irstea in a vineyard catchment (Beaujolais, France). The site is instrumented with lysimeters, flow and solute concentration measurement devices. This test represents a complex step into the model validation, initial and boundary conditions are not fully controlled, and field parameters measurement are not fully known.

International audience; The Andes mountain range provides the setting for watersheds with high natural background of metals and for mining operations that enhance contaminant mobilization, notably in Northern and Central Chile. Dissolved and solid metal species are actively transported by streams to the Pacific Ocean from area and point sources, like acid drainage. We examine the response of metal rich particle suspensions downstream zones of mixing where shifts in the chemical environment occur. We propose a conceptual model which is used to analyze the fate of copper in the upper Mapocho watershed. The main source of copper is the Yerba Loca river, a naturally impacted stream with pH ranging from 3 to 7 and high concentrations of Cu (0.8 - 6.3 mg/L), Al (1.3 - 7.6 mg/L) and Fe (0.4 - 4.2 mg/L). Steep chemical shifts occur after the confluences with the San Francisco and the Molina rivers. We characterized stream chemistry, hydrological variables and suspended particles, including particle size distribution (PSD), turbidity, and total suspended solids. A marked seasonal behavior was observed, with a higher total Cu flux during smelting periods and a shift towards the dissolved phase during summer. When acid drainage is discharged into a receiving stream, incomplete mixing occurs thereby promoting the formation of a range of metal-rich solids with a characteristic PSD. Similarly, areas of chemical heterogeneity control the partition of metals associated to suspended geomaterials coming from bank and slope erosion. A highly dynamic process ensues where metastable phases shift to new equilibria as fully mixed conditions are reached. Depending on the reaction kinetics, some particles persist despite being exposed to thermodynamically unfavorable chemical environments. The persistence of metal-rich particles downstream zones of acid drainage mixing is important because it ultimately controls the flux of metals being delivered to the ocean by watersheds impacted by acid drainage.

International audience; The modeling toolkit BUVARD (BUffer strip for runoff Attenuation and pesticides Retention Design tool) consists in several steps like analyzing the watershed and its characteristics (soil, climate, cultural practices), and running dynamical models, in particular the mechanistic model VFSMOD. At the end this toolkit delivers the optimal VFS width considering the needed filter efficiency (for example, 70% of runoff reduction).The present study aims at making possible to simplify this very complete method, to determine its sensitivity to input parameters in new climatic and agronomic conditions by reducing the computational cost of the modeling toolkit. A metamodel (or surrogate model) developed on local conditions would allow to perform GSA with low cost yet ensuring it is based on physics. It would help users understanding the most important processes in the VFS they want to design and would increase the operational scope of the modeling toolkit. We performed a much smaller sampling of input parameters using the Latin Hypercube Sampling method optimized with a maximin criteria. The metamodel is then be based on a Kriging approach with a very good quality of prediction. It is a promising tool to perform uncertainty analysis and sensitivity analysis at alow cost.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU; International audience; Physically-based models represent detailed surface/subsurface transfer, but the required spatial information does not allow their operational use. In situ data on pesticides in a catchment are usually rare and not continuous in time and space. Satellite images, on the other hand, well describe data in space, but only water related, and at limited time frequency. This study aims to exploit these 3 types of information (model,in situ data, images) with data assimilation methods adapted to image data, in order to improve pesticide and hydrological parameters and better understand physical processes. This poster discusses the proposed methodology as well as the available study site data and modeling components.

International audience; Films of organic compounds exposed to the atmosphere are ubiquitously found on surfaces of cloud droplets, aerosol particles, buildings, plants, soils and the ocean. The sea-surface microlayer is one example of organic films that are host to countless biogenic amphiphilic compounds concentrated there with respect to bulk water. Yet, organic materials present in the bulk, such as humic acids and other photosensitizing compounds, can still have a tremendous impact on the surfactants (George, 2015). Here, we present a laboratory investigation on secondary organic aerosol (SOA) formation from the reaction of ozone with volatile organic compounds (VOCs), originating from photo-induced processes in surfactant-containing water or sea-water. The results underscore the environmental importance of photochemical reactions at the air–water interface to produce SOA precursors in significant amounts, leading to significant particle formation and growth. Laboratory experiments were conducted in a custom-built 2 m3 Teflon reaction chamber with a pure or sea-water reservoir containing nonanoic acid, a model surfactant proxy for a surface microlayer, and humic acids when desired. In other experiments nonanol was used as a surfactant for comparison. VOC concentrations were measured over time using a proton transfer reaction–time of flight–mass spectrometer (PTR–ToF–MS) as a function of irradiation (UV and visible light) in a humidified low NOx and low ozone environment. Additionally, photochemical gas- and liquid-phase products generated by irradiation of natural riverine biofilms were investigated. Characterization of organic compounds in water and aerosol particles was performed with ion chromatography and liquid chromatography–high resolution mass spectrometry (LC–HRMS) utilizing a quadrupole-orbitrap detector. Aerosol size distribution and numbers were continuously monitored during all experiments. Production of VOCs occurred while the chamber air and water were irradiated with UV light for the nonanoic acid and pure water system. Gas-phase products included alkenes, aldehydes and dienes, as observed by PTR–ToF–MS in three different ionization modes (H3O+, NO+ and O2+). Aerosol nucleation and growth occurred upon ozone introduction and reaction in the chamber but with lights switched off, further indicating the presence of unsaturated VOCs. Concentrations of aerosol particles were typically on the order of 102–103 cm–3. When nonanoic acid and seawater were present, similar types and concentrations of VOCs were observed. Production of halogenated organic compounds was investigated using O2+ reagent ions. The addition of humic acids typically enhanced photochemical VOC production and aerosol formation, where SOA numbers exceeded 104 cm–3 after ozone injection and particle nucleation. We note that when nonanol was used as a surfactant, VOC and aerosol formation was never observed. This result highlights the potential importance of the carbonyl functionality of the acid group in the photochemical mechanism. The products were not only emitted to the gas phase, but also the bulk water. Using LC–HRMS the same VOCs, observed with the PTR–ToF–MS in the gas phase, were also identified in bulk water samples extracted during and after experiments. In addition, high molecular weight compounds such as highly oxidized organic molecules and molecular recombination products were identified in experiments with the nonanoic acid surfactant. We suggest that light absorption precedes radical chemistry at the organic surfactant interface. Recent experimental findings in our group, supported by quantum chemical calculations, reveal the possibility of exciting nonanoic acid molecules to their triplet state even under irradiation of 300–320 nm wavelengths. Subsequent inter- and intra-molecular reactions have been proposed generating OH and other radicals leading to a suite of products. At an organic interface neighboring organic molecules are likely to react, especially in molecular layers such as those existing in organic or biogenic films. This proximity of organic molecules is unique to an interface, in contrast to the bulk or gas phase and thus, may also result in unique chemical reaction pathways leading to VOC formation. Fatty acid and organic compound coated surfaces are ubiquitous and photon-induced chemistry at organic interfaces may be important, ultimately influencing VOC flux and SOA formation at the Earth’s surface and aloft. References George, C., Ammann, M., D’Anna, B. Donaldson, D. J., Nizkorodov, S. A. (2015), Chemical Reviews 115 (10), 4218–4258. DOI: 10.1021/cr500648z

International audience; Channelization has increased in piedmont areas with urbanization and other anthropogenic alterations. Changes in riparian structures and in sediment dynamics have affected riparian biodiversity including aquatic macroinvertebrate richness. In this context, riverbank restoration becomes a major issue in preserving stream ecosystem functioning and associated services. As a relevant integrator of environmental changes in river systems, macroinvertebrate communities are likely to readily respond to a combination of anthropogenic disturbances. We aimed at assessing the response of the taxonomic and functional characteristics of benthic macroinvertebrate communities along a gradient of managed riverbank naturalness.

International audience; Ce poster présentent les développements réalisés pour la conception de l'application web BUVARD online, destinée au dimensionnement des bandes tampons végétalisées.

/ Ce poster a pour objectif de présenter de manière vulgarisée le travail des équipes EMHA et Ecotox d'Irstea Lyon et notamment leur utilisation des communautés microbiennes et des invertébrés pour évaluer l'impact des perturbations dans les rivières.

/ Les écosystèmes aquatiques sont soumis à des sources de contamination anthropiques et naturelles contribuant à leur appauvrissement. Le développement d'un biotest sur le sperme de gammare permet l'évaluation de l'impact des contaminants sur la spermatogenèse. La mise en place de ces outils a nécessité : La caractérisation tissulaire de la gonade mâle et de la spermatogenèse. L'étude de la spermatogenèse à l'aide du dénombrement des spermatozoïdes. L'étude de l'impact des contaminants et des rejets de station d'épuration sur la production de spermatozoïdes.

International audience; The urban and periurban area of Copiapó in the arid Atacama desert has more than 30 abandoned mine tailings, one active copper smelter, and 150,000 inhabitants. Fast development of the mining industry during the 19th century and unplanned growth has led to public concern about the presence of metals in soils and street dust. Recent floods and mud currents in the Copiapó watershed have introduced new solid material in about 40% of the urban area. We conducted a geochemical screening before and after the disaster in March 2015. We found concentrations as high as 1000 mg/kg of copper and 180 mg/kg of arsenic in urban soils. Since effective control measures require connecting sites of metal enrichment with the possible sources, we have performed a statistical analysis of metal association and complemented it with other analyses like x-ray diffraction. Cluster analyses of elemental compositions suggest that mud and tailing have different origins from the rest of the matrices, while soils and street dust have a similar one. Some clusters have a mix of matrices that suggest anthropogenic enrichment of some areas of Copiapó. Our initial results indicate that a correlation between observed enrichment and the copper smelter can be hypothesized for Cu, Pb, and Zn. Further spatial, statistical, and chemical analyses are needed to further confirm such findings, complemented with a thorough analysis of the baseline values that could be considered representative of the area. Future work include Principal Component Analysis (PCA) and Positive matrix factorization (PMF) to test the link contaminant sources and metal occurrence, while scanning electron microscopy can be used to identify the presence of smelter-related particles. The information generated by this research will be a necessary input for defining urban planning strategies and land use guidelines, defining health risk assessment studies, and for future evaluation of intervention priorities.

International audience; The presence of toxic metals in watersheds affected by acid drainage (AD) imposes a challenge for sustainable supply of water for cities, agriculture and industry. The formation and settling of metal-rich HFO (hydrous ferric oxides) and HAO (hydrous aluminum oxides) is a relevant mechanism for the attenuation of dissolved metals from AD, particularly for arsenic. Organic matter is known to alter the chemical speciation and key physical properties like particle size distribution (PSD) and settling velocity of HFO and HAO particle suspensions. However, available experimental studies focus either on chemical or physical properties. We used a suite of analytical techniques to probe the effects of organic matter on particle suspensions formed in natural waters and in laboratory model systems. Dissolved organic matter was added at different concentrations (0, 0.1, 0.3, 0.6, 1 and 1.5 mg C/L) to synthetic AD before neutralization with alkaline solutions. PSD and average particle size were measured with laser scattering transmissometry (LISST), while organic matter was characterized by total organic carbon (TOC) and UV-VIS spectrometry. Larger concentrations of organic matter lead to the formation of particle suspensions with larger particle volume and size. When 1.5 mg C/L were added, the total particle volume concentration increased from 0.67 to 23.74 μL/L, while the mean particle size increased from 102 to 176 μm. These results suggests that organic matter influences the fate of metals from AD. Undergoing measurements include total and dissolved metal analyses with total reflection X-ray fluorescence (TXRF) and ICP-OES to confirm increased removal of dissolved arsenic. The results from this research are necessary to understand the processes governing natural attenuation of metal contamination in fluvial systems affected by AD and to serve as the basis for enhanced natural attenuation schemes.

International audience; During the last decade, the interest on the fate of emerging organic micropollutants, including pharmaceuticals and pesticides, in rivers and waste waters has constantly grown. Analysis of these pollutants at trace level in complex matrices is an analytical challenge that requires the development of reliable analytical methods. Based on the conclusions of national research programs on wastewater and sludge treatments and on expert opinions, indicative compounds typical of urban domestic pollution were selected according to i) their frequency of quantification in untreated wastewaters, secondary and tertiary wastewater effluents and in receiving rivers, ii) their toxic effect in aquatic and terrestrial ecosystems, iii) their large range of physico-chemical properties (log Kow, pKa) and chemical classes. Finally, 49 targeted compounds were selected, including 8 pesticides, 35 pharmaceuticals compounds (antibiotics, antidepressants, betablockers, anti-inflammatories, hypolipemiants and anticarcinogens) and 6 metabolites, to be part of a multiresidue method. This method also includes 4 priority substances (simazine, atrazine, diuron and isoproturon) of the Water Framework Directive (WFD, 2000/60/CE) and one watch-list substance (diclofenac) of the WFD daughter directive (2013/39/UE). After collection in field, water samples were filtered and acidified. Samples were concentrated and purified by solid phase extraction (SPE). Twenty-two stable isotope labelled compounds were used as surrogates to overcome matrix effects generated during whole analytical procedure. Ultra high performance liquid chromatography (UHPLC) coupled to electrospray (both positive and negative ionization) tandem mass spectrometry was performed in the multiple reaction monitoring (MRM) mode, so molecule identity could be confirmed by two quantitation and confirmation transitions according to the EC Commission Decision (2002/657/CE), except for diclofenac. We present accuracy, linearity and limits of quantification (LOQ) in intermediate fidelity conditions (intra-laboratory reproducibility), evaluated in real waters. As examples of application, we present concentration ranges for these compounds measured in rivers and wastewaters.

International audience; Surface waters of the Ardières and Morcille Rivers (South-East France) are historically polluted by arsenic (As), with total dissolved As concentrations reaching up 40 µg/L. High frequency monitoring of surface waters during 3 years showed a strong seasonal variability of total dissolved concentrations of As, with low concentrations in winter (high-water level, 2-3 µg/L) and high concentrations in summer (low-water level, 20-40 µg/L). These findings suggest a more pronounced input of low- oxygenated water from groundwater to the river during summer than during winter period. Under this assumption, we suggest that during summer, dissolved concentrations of reduced As (As III) are probably higher than during winter period. Since the reduced form of As (As III) is known to be more toxic than the oxidized form of As (As V) for aquatic organisms, there is a need to assess temporal variability of inorganic As speciation in these surface waters. Nevertheless, inorganic forms of As are unstable, especially when parameters such as pH and/or redox vary. Passive sampling technique such as Diffusive Gradient in Thin films (DGT) presents several advantages to better assess in-situ As speciation, by eliminating problems of contamination and especially by reducing modification of speciation during steps of sampling and storage by directly trapping in-situ As III and As V. Thus, we worked with commercially available DGT with a resin constituted by ferrihydrite (DGT-FH). We first determined diffusive coefficients of As III and As V by realizing kinetic experiments. Then, we tested several extractants (HNO3 0.8M, HNO3 1M, HCl 4M with acid acetic 10% and hydroxylamine 0.4M) to extract As III and As V with a good reproducibly, by minimizing transformation of As III into As V and by optimizing limit of quantification during analysis by HPLC-ICPMS. To finish we deployed triplicates of DGT-FH during 1 week in summer and in winter on the Ardières and Morcille Rivers to assess inorganic As speciation. Kinetic experiments allowed determining diffusive coefficients for As III (6.52 10-6 cm² s-1) and As V (4.76 10-6 cm² s-1) which are in the same range than those found in literature. Experiments realized in situ showed that DGT-FH was well adapted to trap in-situ As III and As V during the summer campaign. Results highlighted that during this low-water level, As III concentrations in surface waters were ~1 µg/L accounting for 5 to 10 % of total dissolved concentrations. Results of the winter campaign are in progress. This study provided the first attempt to develop a method allowing to extract inorganic species of As previously trapped in-situ by DGT-FH and to analyze by HPLC-ICP-MS. This approach allows us to better characterize, by passive sampling method, temporal exposition of aquatic organisms to As species in surface water.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; International audience; Most monitoring programs for surface waters within a legislative framework such as the Water Framework Directive (WFD) rely on conventional techniques such as spot or automated sampling to determine total dissolved concentration of a target substance. These sampling methods are generally time-consuming, do not take into account temporal variability and could induce samples contamination, loss of analyte or speciation modifications. The Diffusive Gradient in Thin films (DGT) technique is an alternative sampling method to assess a time-weighted average (TWA) metal concentration in surface waters, as it takes into account metal variations during the period of exposure. This passive sampler based on a polyacrylamide diffusive gel and a Chelex resin has been widely used to measure TWA concentration for cationic metals such as cadmium (Cd), nickel (Ni), lead (Pb), zinc (Zn) and copper (Cu). Recently, the gel and/or the resin were modified to propose a similar tool allowing trapping mercury (Hg) species and arsenic (As). These different tools are commercially available but several laboratories are now developing their home-made DGTs. As each laboratory prepares its home-made gel or resin in different working conditions by using different reagents (i.e. purity and/or supplier) and by using different methods to determine diffusive coefficient the comparison of results obtained with these tools could be not relevant. To answer this question, the objective of our study was to compare commercial and “home-made” DGT performances for cationic metals (Cd, Pb, Ni, Cu, Zn, Co) and total mercury during an in situ intercomparison exercise. The in situ intercomparison exercise was carried out in July 2014 in the Deûle River (northern France) for 2 weeks. Results were addressed in terms of (i) blank values, (ii) accumulated metal mass and (ii) TWA concentration by overcoming the analytical bias. First results highlighted the effect of different working conditions on blank values and their impact for the determination of TWA concentrations. Additionally, data showed the importance of characterizing diffusion coefficients for each type of home-made DGT in order to compare them.

International audience; Grab sampling may be scarcely adequate to evaluate the impact on surface waters of pesticide used in agriculture because of its poor spatiotemporal representativeness compared to the high variability of the contamination patterns. Indeed, it is still not easy to link the effect of agricultural practice changes to water quality at the catchment scale. Furthermore, biological indicators may also be useful in addition to pesticide concentration determination to evaluate their impact on ecosystems. In this way, the contribution of new integrative tools has been evaluated. Passive samplers and biological indicators have been applied together at the catchment scale so as to identify their coherence and complementarity. The tested chemical tools are the passive-SBSE (Stir Bar Sorptive Extraction) dedicated to hydrophobic to moderately hydrophilic compounds and the POCIS (Polar Organic Chemical Integrative Sampler) dedicated to hydrophilic compounds. As concerns biological approach, it consisted in the in situ deployment of i) caging methodology with a highly ecological relevant amphipod species, Gammarus fossarum, coupled to the measurement of toxicity markers (acetylcholine esterase inhibition, feeding rate) and ii) the study of microbial and macro-invertebrate communities (measurement of leaf decomposition rates) as well as phototrophic periphytic communities (measurement of Pollution Induced Community Tolerance). These tools have been applied during june 2014 (corresponding to vineyard and corn period of application) in two contrasted agricultural catchments. The Ardières basin situated in the Beaujolais region (France) is submitted to viticulture pressure and a marked pesticide contamination has already been highlighted. Three measurement stations have been chosen so as to search for a contamination gradient from upstream to downstream. The Coise basin is located in the Monts du Lyonnais (France) in a zone of mixed farming breeding with a predominance of meadows, corn and cereals. Three measurement stations have been selected on three sub-catchments corresponding to differentiated pesticide use. In total, 49 pesticides (28 herbicides, 9 fungicides and 12 insecticides) have been analyzed as well as potential confusing parameters (metal(oïd)s, nutrients, temperature, luminosity, water flow). Results show the high coherence of chemical and biological tools responses. All of them were able to reflect the spatial contamination gradients as well as the specific contamination and impact associated to each agro-pedo-climatical context. A weekly exposure also permitted to take into account the temporal variability of the contamination according to flood occurrence. Finally, their sensitivity, reactivity and integration capacity make these tools relevant and promising to assess agricultural pesticide impact on surface water in addition to grab sampling.

International audience; The use of pesticides in agricultural fields leads to nonpoint source contamination of freshwaters by various pathways (runoff, infiltration, lateral flows…). Different research programs have been developed to study and explain these transfer mechanisms. They required specific sampling strategies for each compartment of the aquatic environments. Passive sampling has been introduced as an alternative to grab or average automated sampling, in order to obtain at lower cost, more realistic estimates of the contamination levels of pesticides in water. This technique allows the in situ accumulation of chemicals over exposition periods ranging from days to months. Silicone rods, investigated in this work, are single-use and low cost new passive samplers. Extraction and quantification of pesticides from silicone rods were performed by liquid desorption followed by UHPLC-MS/MS. The nature and mass of pesticides sorbed on in situ exposed silicone rods can be used as qualitative and semi-quantitative measures to assess trends or gradients of contamination at different scales: from plots to rivers or watersheds. The aim of this study was to investigate the use of silicone rods as a passive sampling technique in different water bodies and to assess their benefits for the monitoring of pesticides and metabolites with various physico-chemical properties. Firstly, silicone rods have been exposed during one month (four exposition periods of one week) in a river located in a vineyard watershed with a marked pesticide contamination. Fifteen pesticides, mainly fungicides, were sorbed on silicone rods, but also insecticides that could not be detected in parallel grab samples. A strong gradient of contamination was clearly shown according to the increase of land use. Contamination reaches a maximum in the second week corresponding to a rainy period after a dry one. A second application of silicone rods consisted in their deployment inside a network of piezometers in an instrumented vineyard plot to evaluate the spatial propagation of pesticide contamination during a rainfall event. Silicone rods allowed for the qualitative detection of seventeen pesticides from different families and origins. The spatial dispersion of pesticides highlighted a strong axial subsurface transfer following the slope of the plot. The comparison of upslope and downslope masses of pesticides sorbed on the rods permitted to discriminate the behaviour of the pesticides either in controlled conditions (for pesticides injected during a simulation event) or in natural conditions (for pesticides applied on the plot by the farmer). We illustrated here that sensitive passive samplers can now be considered as an alternative or complement to grab sampling to improve the monitoring of pesticides in aquatic environments by integrating pesticide concentration variations over exposition periods.

International audience; Conventional wastewater treatment plants (WWTPs) partially eliminate micropollutants present in domestic and industrial discharges (Martin-Ruel et al., 2010; Choubert et al., 2011). However, some molecules still occur in effluents of WWTPs at concentrations close to 0.1 μg/L for some pesticides (e.g. diuron) and pharmaceuticals (e.g., carbamazepine, sotalol, diclofenac). The potential hazard of these compounds requires the development of new processes (tertiary) to anticipate possible regulation changes. This poster focuses on study of 11 compounds (pesticides and pharmaceuticals) during degradation process in tertiary treatments such as ozonation or photodegradation. The aim of this communication is to present our analytical methodology to identify degradation products (DP) created under controlled conditions during lab-scale experiments. Both direct and indirect ozonation of spiked WWTP effluent at about 1 µg/L was driven on a lab-scale apparatus at two different O3 concentrations (4.3 and 9.5 gram per gram of dissolved organic carbon). Photodegradation was studied in laboratory with ultrapure water spiked at 10 µg/L using a light box equipped with a xenon lamp. Analysis of parent and degradation products were performed on a Waters ACQUITY H-Class UPLC system coupled to Xevo G2-S high resolution mass spectrometer using a quadrupole-time of flight technology. The separation was performed on a C18 HSS-T3 column (100mm x 2.1mm, 1.7µm) after direct injection. Acquired centroid raw data were processed quantitatively for parent compounds using TargetLynx and qualitatively for degradation products identification using ChromaLynx applications manager for MassLynx 4.1 software. Such strategy combined a classical targeted analysis with quantitative approach and a retrospective database comparison for suspected-target screening of more than 150 potentially DPs. Results and discussion are focused on criteria and clues to identify DP. Scoring of evidences is based on proposed identification confidence levels described by Schymanski et al. (2014).

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU; International audience; A long-term goal of the Rhône Sediment Observatory is to quantify suspended particles and associated contaminant fluxes along the Rhône River from Lake Geneva to the Mediterranean Sea, from hydrological event to annual scales. Facing the complexity to evaluate these fluxes, an original observation strategy was developed to produce dense datasets regarding liquid discharges, suspended particulate matterloads (from turbidity), particle-size, organic and inorganic contaminant concentrations from centrifuge or sediment trap samples. Eventually, continuous time-series and flux calculation were established and made available in an efficient database (BDOH/FluxOSR).

International audience; Kinetic models are used to link metal exposure to metal contamination in aquatic organisms and enable also the prediction of metal bioaccumulation. Kinetic models are characterised by kinetic parameters (uptake and elimination rate constants) which can be determined in controlled conditions. “Global” kinetic parameters for Cd, Pb and Ni have been established in five naïve populations of gammarids. Gammarids can, however, live in rivers exhibiting metal contamination to which organisms may adapt physiologically. Adaptation can result in the modulation of bioaccumulation abilities i.e. kinetic parameters. This may limit the environmental relevance of kinetic models and the reliability of bioaccumulation predictions. The aim of thsi study was to assess the bioaccumulation abilities of metals in gammarids chronically exposed to metals in situ by (i) determining the kinetic parameters describing Cd, Pb and Ni bioaccumulation in populations of gammarids chronically exposed to metals in situ, (ii) comparing the kinetic parameters with “global” kinetic parameters already determined in five naïve populations of gammarids.

International audience; Among freshwater species intensively used in ecotoxicology, Gammarus fossarum is a relevant test species. In addition to its sensitivity towards contaminants, this species is a common shredder which plays a major role in leaf litter breakdown processes. Many sub-individual and individual responses have been proposed in gammarids in order to monitor and predict effects of chemical compounds on water quality. In this framework, energetic metabolism variations appear to be a good predictive tool to detect physiological disturbance of organisms linked to ecosystem quality. Indeed animal survival depends on the availability of metabolic energy necessary to ensure maintenance, growth and reproduction. Among biological processes to access energy, digestive capacities appear sensitive to contamination stress. In recent studies, based on the use of one reference population, reference and threshold values for digestive enzymes proposed as biomarkers were defined. In the same way, the same research team described link between digestive changes and reproductive impairments. So digestive capacities appear as potential ecologically relevant endpoints to provide information on the consequences likely to occur at the highest hierarchical levels of organization (population). However the use of only one experimental population is not representative of biological diversity. In this way, it appears necessary to precise the between-population variability of these enzyme activities. Among more than 40 sites investigated, 8 populations of Gammarus fossarum considered as reference were selected. On these populations a double approach was applied. In a first step, the basal level of digestive enzyme activities were studied after an acclimation of organisms to similar laboratory conditions. In a second step, the pattern of digestive capacities modulation in the 8 poulations exposed at a similar stress (trophic stress) were considered. This second step aims to identify a potential difference of sensitivity between the eight populations. The results of this preliminary study, underlying changes in digestive enzymes activities, will be discussed according to environmental parameters which could be implied (different sources of food according to the site) but also concerning the potential consequences on the reference and threshold values define previously via one control population.

International audience; Comprehension and prediction of ecological effects related to environmental contamination calls for improvement of risk assessment approaches and validation of existing methods. As regards to metals, the prediction of ecological disturbance through the assessment of bioavailability is limited to the use of approaches not successfully validated in situ. Metal-related risk assessments should integrate results from field studies about the relationship between bioavailable concentrations and ecological response. In this aim, 1/ biota (which reflect bioaccumulation and bioavailability) should be used to estimate water contamination level, and 2/ the relationship between concentrations in biota and ecological response should be characterised. The validation of this approach at a wide scale could reveal the existence of a universal threshold for metal concentrations in a given biomonitor above which adverse ecological effects appear. Previous studies mainly rely on passive biomonitoring: the presence of the test organism is required in situ and the influence of confusing factors may be neglected. Active biomonitoring with transplanted organisms collected from the same population enables to overcome these drawbacks. Our work aimed at calibrating the active biomonitor Gammarus fossarum by relating the concentrations measured in in situ caged organisms to local ecological indicators. 129 sites were investigated in France, for which relevant ecological and chemical data were available. Controlled batches of gammarids were exposed during 7 days. Metals were analysed by ICP-MS (Cd, Pb, Ni, Co, Ag, As, Zn, Cr, Cu) or automated AAS (Hg). For most metals, bioaccumulation was significant with ratios between the lowest and the highest values related to the essential or non-essential character of the metals, confirming the relevance of this species to monitor metal contamination in freshwater systems. For all metals, results showed no relationship between bioaccumulation levels and global ecological disturbance. On the contrary, for Cd and Pb, a clear relationship was established between the concentration in caged organisms and the abundance of metal-sensitive invertebrates. Metal concentration in G. fossarum can be quantitatively related to metal-specific adverse responses in stream invertebrates. Dose-response curves, defined for each metal at the national scale, indicate that contamination measured in caged organisms could be used to manage the risk of metallic contamination.

International audience; In Europe, a significant presence of contaminants is found in surface water, partly due to pesticide applications. Vegetative filter strips or buffer zones (VFS), often located along rivers, are a common best management practice (BMP) to reduce non point source pollution of water by reducing surface runoff. However, they need to be adapted to the agro ecological and climatic conditions, both in terms of position and size, in order to be efficient. The TOPPS-PROWADIS project involves European experts and stakeholders to develop and recommend BMPs to reduce pesticide transfer by drift or runoff in several European countries. In this context, Irstea developed a guide accompanying the use of different tools, which allows designing site-specific VFS by simulating their efficiency to limit transfers using the mechanistic model VFSMOD. This method which is very complete assumes that the user provides detailed field knowledge and data, which are not always easily available. The aim of this study is to assist the buffer sizing by using a unique tool with a reduced set of parameters, adapted to the available information from the end-users. In order to fill in the lack of real data in many practical applications, a set of virtual scenarios was selected to encompass a large range of agro-pedo-climatic conditions in Europe, considering both the upslope agricultural field and the VFS characteristics. As a first step first, in this work we present scenarios based on North of France climate consisting of different rainfall intensities and durations, hillslope lengths and slopes, humidity conditions, a large set of field rainfall/runoff characteristics for the contributing area, and several shallow water table depths and soil types for the VFS. The sizing method based on the mechanistic model VFSMOD was applied for all these scenarios, and a global sensitivity analysis (GSA) of the VFS optimal length was performed for all the input parameters in order to understand their influence and interactions, and set priorities for data collecting and management. Based on GSA results, we compared several mathematical methods to compute the metamodel, and then validated it on an agricultural watershed with real data in the North-West of France . The analysis procedure allows for a robust and validated metamodel, before extending it on other climatic conditions and typical european watersheds . The tool will allow comparison of field scenarios, and to validate/improve actual existing placements and VFS sizing

International audience; "Flood control" policies have now shifted to "integrated flood risk management", which should also blend nicely within "water management" and "sustainable development". Thus, flood risk reduction strategies are one element to define in coordination with others in a broader picture. From a practical point of view, the relevance of flood management projects must now be examined under several angles. This is where Multi-Criteria Analysis is useful: they assess objectively the impact of projects through different indicators, either to guide decision-making by the project manager, or even to obtain final authorizations and/or funding. Here, we advocate that it could be used as guidance throughout all the stages of the project, to ensure informed decisions at each step, from the definition of the project broad lines to the choices of technical details. We propose here a practical method to define the best compromise between the different disciplines involved by the project, and all along the process. The idea is to make the best use of the competences of each involved person, including technical staffs. Co-conception implies the active participation of all. Therefore, our approach insists that first the objectives have to be explicit and shared, and that solutions must be found to discuss and compare the means of action, using common conceptual and operational views. Our approach still has to be implemented for full-scale studies, in real and varied contexts, to test and improve the method to a fully operational stage. Only then can "guidelines' be written, but always allowing much freedom in the implementation. Future implementations should be followed closely, certainly not to control the process, but to capitalize on the experience. Social sciences should be closely associated to the project, to analyze the paths towards solutions: how different specialists collaborate, which were the expected and unexpected misunderstandings at the beginning, how they were identified and solved, how compromises were made, how each specialist around the table really influenced the final version of the project. Of course, each project is different, but feed-back analysis can always bring insight to the delicate art of project management and help identify obstacles and solutions for fruitful co-conception.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; International audience; Approaches for the assessment of environmental impacts of contamination rely on toxic effects observed mainly at the individual level. These effects are then extrapolated to higher levels of biological organization (population, community and ecosystem) that constitute the protection goals of environmental regulations (REACH, WFD). Individual performance is governed by the allocation of energy to the physiological processes. DEB theory (Dynamic Energy Budget) formalizes the allocation of energy to key physiological functions (growth, maintenance and reproduction). However, until now, these models assume a permanent energy allocation to the reproduction during the lifespan of an organism, while it is generally a discrete process driven by physiological constraints. This is particularly true for crustaceans for which reproduction is synchronized with molt, such as Gammarus fossarum, a keystone species playing an important role in the functioning of European freshwater ecosystems. The aims of our presentation are (1) to present a mechanistic DEB model describing the allocation of energy during a reproductive cycle of G. fossarum females exposed to different temperatures and (2) to illustrate how it can be used under stress conditions. According to the knowledge on G. fossarum reproductive cycle, we schematized the biomass fluxes occuring during a reproductive cycle and formalized them by six differential equations. Considering different temperatures and different sizes of females allowed to consider different feeding rate values for the calibration of energetic processes implied during a reproductive cycle. Parameters were then estimated by Bayesian inference: we obtained precise estimations for the parameters. In particular, we estimated that females allocate 12% [0.11-0.14] of the assimilated energy to reproduction and predicted that 83% of the observations were within the predictive credible intervals. The model was then validated on other data. Finally, we fixed the scheme of energy allocation and compared the model predictions with lower food inputs to what is observed when females are under such food limited conditions. We showed that the more the food was restricted, the more the model underestimated reproduction, meaning that energy allocation was modified to privilege reproduction. Our study shows how a DEB formalism may describe the energy allocation processes of a crustacean for which reproduction occurs in a discrete way during successive molts.

Human induced-physical habitat alterations are the main threat to aquatic ecosystems. In a context of climate change, these alterations could be exacerbated by changes in low flow regimes, inducing modifications of aquatic communities. Understanding the links between aquatic communities, their physical habitat and climate change is therefore a major but difficult challenge because climate change can interact with other anthropogenic pressures, thus confounding their effects. In this study, we simulate potential macroinvertebrate hydraulic habitat alterations due to predicted more extreme low flows on the Loire River watershed, regardless of other anthropogenic pressures. By coupling a species distribution model and a habitat model that combines a model of shear stress distribution with a macroinvertebrate preference model, we are able to point out changes in community structure in response to shifts in habitat availability. By isolating more extreme low flows effects on macroinvertebrate communities, we emphasize natural sensitivities to climate change and provide a frame to better understand how anthropogenic pressures could exacerbate them.

International audience; Developing macrophytes-based methods for assessing the ecological status in rivers needs to deal with different analyze scales: floristic data are recorded at the site scale while the anthropic pressures are defined at large scale of catchment area. Thus, the response of the macrophytes communities cannot be directly explained by the catchment features. To focus on the hydromorphology highlights the needs of multi-scales approach. Indeed these environmental parameters cover functioning (hydrology) and characteristics (substrate, river shape) at nested scales. The search for sensitive macrophytes metrics assessing the impact of environmental parameters, especially for the hydromorphological aspects, were tackled by 1/ determinate the relationship between population and habitat at the site scale, 2/ understand the links between large-scale pressure and local morphological feature, 3/ analyzing the correlations between both scales and biocenosis characteristics. This approach was undertaken using the French WFD biological monitoring (over 4000 surveys). A set of biological (IBMR, growth forms, vegetal cover) and environmental metrics was defined and tested as integrating meta-data. A PLS modeling distinguishing pressures at catchment, reach and site scales was used in order to respect the hierarchical spatial organization. This multi-scalar method was developed to identify and quantify the biotic response through these different scales.

International audience; Andean watersheds in Northern and Central Chile are naturally enriched with metals, many of them associated to sulfide mineralizations related to copper mining districts. The natural and anthropogenic influx of toxic metals into drinking water sources pose a sustainability challenge for cities that need to provide safe water with the smallest footprint. This work presents our study of the transformations of copper in the Yerba Loca-Mapocho system. Our sampling campaign started from the headwaters at La Paloma Glacier and continues to the inlet of the San Enrique drinking water treatment plant, a system feeding municipalities in the Eastern area of Santiago, Chile. Depending on the season, total copper concentrations go as high as 22 mg/L for the upper sections, which become diluted to

Ovaries were taken from five sexually mature amphipods: Gammarus fossarum, Gammarus pulex, Gammarus roeseli, Hyallela azteca and Parhyale hawaiensis. The soluble proteome extracted from individual pair of ovaries from five biological replicates was trypsin digested and the resulting peptides were analyzed by high resolution tandem mass spectrometry. The spectra were assigned with four protein sequence databases with different specificities: a RNAseq-derived G. fossarum database; a RNAseq-derived P. hawaiensis database; both originating from ovaries transcriptome; the Daphnia pulex database derived from whole-genome sequencing and the NCBInr database. The best interpretation was obtained for most animals with the specific RNA-seq protein database previously established by means of RNAseq carried out on G. fossarum. Proteins identified in the five amphipod species allow defining the core-proteome of female reproductive tissues of the Senticaudata suborder. The data accompanying the manuscript describing the database searches and comparative analysis Trapp et al., 2015 [1] have been deposited to the ProteomeXchange with identifiers http://www.ebi.ac.uk/pride/archive/projects/PXD002253 (G. fossarum), http://www.ebi.ac.uk/pride/archive/projects/PXD002254 (G. pulex), http://www.ebi.ac.uk/pride/archive/projects/PXD002255 (G. roeseli), http://www.ebi.ac.uk/pride/archive/projects/PXD002256 (H. Azteca), and http://www.ebi.ac.uk/pride/archive/projects/PXD002257 (P. hawaiensis).

/ D'une façon générale, un corridor représente une emprise spatiale garante de la connectivité dans un réseau écologique. Pour les cours d'eau, cette notion est non seulement liée à une zone spatialement identifiée comme riparienne, ou corridor rivulaire, qui se définit comme une bande de végétation naturelle située le long d'un cours d'eau, Mais, c'est également un milieu où se cumulent de nombreuses fonctionnalités écosystémiques : zone tampon, filtre d'épuration, zone de provision et de rétention de nutriments, habitat, écotone et couloir de connexion, de contact et d'échange. L'étude du corridor rivulaire est par conséquent indissociable de celle de la rivière, de son paysage et de son bassin versant. Quelles sont les échelles pertinentes à considérer pour appréhender la continuité écologique des corridors rivulaires? Comment construire une approche qui tienne compte de l'échelle de réalisation des processus d'échange et de contact ? Le focus de mes travaux au laboratoire d'hydroécologie quantitative repose sur les cours d'eau à l'échelle large de la France avec une attention particulière portée à leur structure et leur fonctionnement hydromorphologique. Les altérations physiques, la fragmentation des habitats, mais aussi la pollution se présentent comme des pressions emboîtées à différentes échelles, qui peuvent se cumuler au sein des réseaux hydrographiques. Pour correctement identifier leurs impacts et pouvoir y remédier, il fallait mobiliser de nouveaux concepts et bâtir un programme de recherche à moyen terme pour développer de nouvelles méthodes d'analyse hiérarchique, notamment pour caractériser la notion de connectivité. Le travail repose sur une sélection de variables spatiales d'intérêt, concrétisée ensuite par leur extraction géomatique à partir de bases de données couplées à des systèmes d'informations géographiques ou à partir de documents cartographiques, incluant par exemple l'imagerie à très haute résolution spatiale. Ces caractéristiques, résumées par des indicateurs spatiaux qui renseignent les ruptures de continuité, sont ensuite utilisées pour explorer avec un nouveau regard et une ouverture du champ spatial (réseaux hydrographiques, effets amont aval) des relations fonctionnelles entre corridor et différents processus ou réponses écologiques.

The objective of this study is to evaluate the influence of soil hydrodynamic characteristics variability on surface and subsurface flows at a vegetative buffer strip scale, using mechanist modeling. Cathy (CATchment HYdrology, Camporese et al. 2010) is a research partial-differential-equation-based model, solving Richards equation in 3 dimensions for water fluxes in the soil, and a simplified scheme of Navier-Stokes equation for surface runoff. Its particularity is to handle interactions between surface and subsurface, which is a key point concerning water but also solute transport in vegetative filter strips. Balance between runoff and infiltration, flow pathways, water content, are very sensitive to hydrodynamic characteristics, especially saturated hydraulic conductivity (Ksat). This soil property is very difficult to measure and to describe at a fine scale, since it is highly variable spatially in the 3 dimensions. Models described by PDE such as Richards equation need a value of Ksat at each soil layer and each node, though simpler conceptual modeling run with average values of larger cells or storages, using some 'representative Ksat' at a larger scale. This kind of models however can simulate with high quality the processes despite the simplifications they make on parametrization. Using a mechanist and physically-based modeling, we evaluate the influence of Ksat high spatial variability on fluxes, by comparison with observations from an experimental vegetative filter strip. It should allow to understand until which degree of simplification one can describe hydrodynamic characteristics in modeling for more conceptual models.

/ L'usage des végétaux aquatiques dans les filières de traitement des eaux provient de l'observation du rôle des zones humides naturelles dans la préservation de la qualité des milieux aquatiques. En France l'expérience a démarré en 1978. Depuis les premières réalisations jusqu'au début des années 2000 la filière a été évaluée principalement par des bilans 24 h à chaque étape de traitement. Si cette méthode considère les systèmes comme une boîte noire et ne donne pas accès à la quantification des mécanismes impliqués au sein du système, elle a permis néanmoins de poser les premières règles de dimensionnement. Cette approche pragmatique a permis de fiabiliser le dimensionnement et de crédibiliser la filière classique. Cependant, certaines questions restaient en suspens comme le comportement des filtres dans des conditions extrêmes (limites hydrauliques, limites organiques) et la nécessaire évolution de la filière pour l'amélioration des performances (dénitrification, phosphore ...). De même, le succès de la filière a généré des intérêts à associer les filtres à d'autres systèmes de traitement (lagunage naturel, lits bactériens, disque biologiques ...) ou de développer la filière pour d'autres types d'applications comme le traitement des boues ou les surverses de déversoir d'orage. Mon activité de recherche a reposé sur l'objectif de développer et d'encadrer le développement des systèmes extensifs de traitement des eaux et des boues d'épuration. La démarche mise en ½uvre associe différents niveaux. Un niveau structurel (comment organiser la recherche et l'appui technique face à une demande très forte) ainsi qu'un niveau scientifique (quelles méthodologies développer pour lever les verrous scientifiques). Les axes de développement sont liés soit à l'amélioration des performances (niveaux de rejet plus stricts, optimisation de l'emprise au sol, du coût ...) soit au développement de nouveaux domaines d'application (eaux urbaines de temps pluie, matières de vidange ...). La difficulté, à l'instar de tout procédé biologique, réside dans le fait que les filtres plantés sont des écosystèmes complexes qu'il n'est pas possible d'étudier par le biais d'une seule discipline. L'hydraulique, la chimie, la microbiologie, la physiologie végétale, sont autant de domaines scientifiques qu'il convient de prendre en compte pour comprendre les mécanismes et équilibres qui gèrent ces systèmes. L'objectif était de faire évoluer la recherche d'une analyse pragmatique des systèmes (de type essais-erreurs), vers une approche déterministe pour préciser les mécanismes ainsi qu'une approche mécaniste par la création de modèles dynamiques complexes. Le rapport montre comment les recherches menées ont permis de faire évoluer la filière pour répondre à des problématiques non maîtrisées jusqu'alors (réseau unitaire, azote, phosphore, association de procédés, réduction de l'emprise au sol, traitement des boues et matières de vidange, traitement des rejets urbains de temps de pluie...). Pour cela, une forte évolution des approches de recherche a été nécessaire pour étudier plus finement les mécanismes hydrauliques, chimiques et biologiques des ouvrages de traitement. Cette approche fait intervenir la modélisation mécaniste et le transfert de ces connaissances via des outils d'aide au dimensionnement des ouvrages pour l'ingénierie. Les pistes futures sont présentées aussi bien sur les problématiques opérationnelles à court terme pour les eaux usées domestiques (Intensification des filières pour le traitement des eaux usées domestiques, usage de matériaux alternatifs, problématique du colmatage ...) les eaux pluviales et les boues que, à moyens et longs termes, des champs d'application nouveaux pour l'application dans les pays du sud ou s'adapter à l'évolution de la gestion des eaux dans la ville. Ces problématiques opérationnelles sont à associer avec des problématiques scientifiques pour mieux comprendre les mécanismes impliqués (dynamique de la matière organique, transferts d'oxygène ...) et intégrer ces connaissances des différents processus dans la modélisation mécaniste. Pour cela de nouveaux outils seront à utiliser comme par exemple ceux issus de la biologie moléculaire.

International audience; Method development and validation for the analysis of 20 hormones (including estrogens, androgens and progestagens compounds) in various aqueous matrices. During the last twenty years, consumption of hormones compounds (natural hormone or synthetic analogue) mainly for human medicine has considerably increased. Both androgens, progestogens and estrogens compounds are usually not entirely metabolized and reach aquatic environment mainly via effluents of wastewater treatment plants. All of them can be considered as endocrine disrupting compounds because of undesirable effects in biota. Hence, highly sensitive and selective analytical method is needed to identify and quantify these emerging contaminants in various environmental compartments. The aim of this communication is to show the different steps for development and validation of an analytical method for 20 hormonal compounds (estrone [E1], 17 estradiol [aE2], 17 estradiol [bE2], 17 ethynylestradiol [EE2], estriol [E3], androstenedione [ANDRO], androsterone [ANDROSTER], cortisone [CORT], cortisol [CORT-OH], dexamethasone [DEXA], dienestrol [DIEN], diethylstilbestrol [DES], drospirenone [DROSPI], epitestosterone [ETESTO], levonorgestrel [LEVO], medroxyprogesterone [MEDRO], megestrol acetate [MEGAC], norethindrone [NORET], progesterone [PROG], testosterone [TESTO]) in aquatic environments chosen because of their strong or potential endocrine-disrupting potency in river and wastewater. The sample pretreatment procedure that has been determined with a simple experimental screening design (Statgraphics software from SigmaPlus was used for data processing) consists of an extraction on polymeric based phase followed by purification on normal phase (Florisil). Eighteen stable isotope labelled compounds were used as surrogates to overcome matrix effects generated during whole analytical process. Ultra high performance liquid chromatography (UHPLC) coupled to electrospray (both positive and negative ionizations) tandem mass spectrometry is performed in the multiple reaction monitoring (MRM) mode, so molecule identity can be confirmed by two quantitation and confirmation transitions according to the EC Commission Decision (2002/657/CE). Accuracy and limits of quantification in intermediate fidelity conditions (intra-laboratory reproducibility) have been evaluated in accordance with the French standard (NF T90-210, 2009) on different aqueous matrices.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA; International audience; Since Pb and Cd are both non-biodegradable and non–essential, they represent a serious threat for aquatic ecosystems. Metal determination in aquatic organisms such as gammarids offers encouraging perspective to monitor water quality. However, metal uptake in organisms may be influenced by water cationic composition because of competition processes on biological binding sites. The development of bioaccumulation models constitutes promising tools to quantify metal bioavailability and predict metal impact on aquatic ecosystems. In order to arise such models, it is necessary to formalize the abilities of organisms to regulate metals and water chemistry effects in controlled conditions. However, what is the environmental relevance of experimentally derived models to predict bioaccumulation in field conditions?