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International audience; Preservation of biodiversity and ecosystem services is critical for sustainable development and human well-being. However, an unprecedented erosion of biodiversity is observed and the use of plant protection products (PPP) has been identified as one of its main causes. In this context, at the request of the French Ministries responsible for the Environment, for Agriculture and for Research, a panel of 46 scientific experts ran a nearly 2-year-long (2020-2022) collective scientific assessment (CSA) of international scientific knowledge relating to the impacts of PPP on biodiversity and ecosystem services. The scope of this CSA covered the terrestrial, atmospheric, freshwater, and marine environments (with the exception of groundwater) in their continuity from the site of PPP application to the ocean, in France and French overseas territories, based on international knowledge produced on or transposable to this type of context (climate, PPP used, biodiversity present, etc.). Here, we provide a brief summary of the CSA's main conclusions, which were drawn from about 4500 international publications. Our analysis finds that PPP contaminate all environmental matrices, including biota, and cause direct and indirect ecotoxicological effects that unequivocally contribute to the decline of certain biological groups and alter certain ecosystem functions and services. Levers for action to limit PPP-driven pollution and effects on environmental compartments include local measures from plot to landscape scales and regulatory improvements. However, there are still significant gaps in knowledge regarding environmental contamination by PPPs and its effect on biodiversity and ecosystem functions and services. Perspectives and research needs are proposed to address these gaps.

To assess the risk of pesticide mixtures in lagoon waters, this study adopted a multi-step approach using integrative passive samplers (POCIS) and concentration addition (CA) toxicological models. Two French Mediterranean lagoons (Thau and Or) were monitored for a range of 68 pesticides continuously over a period of a year (2015-16). The findings revealed mixtures of dissolved pesticides with varying composition and levels over the year. The Or site contained more pesticides than Thau site (37 vs 28 different substances), at higher concentrations (0.1-58.6 ng.L

There is growing interest in using the ecosystem services framework for environmental risk assessments of plant protection products (PPP). However, there is still a broad gap between most of the ecotoxicological endpoints used in PPP risk assessment and the evaluation of the risks and effects of PPP on ecosystem services. Here we propose a conceptual framework to link current and future knowledge on the ecotoxicological effects of PPP on biodiversity and ecological processes to their consequences on ecosystem functions and services. We first describe the main processes governing the relationships between biodiversity, ecological processes and ecosystem functions in response to effects of PPP. We define 12 main categories of ecosystem functions that could be directly linked with the ecological processes used as functional endpoints in investigations on the ecotoxicology of PPP. An exploration of perceptions on the possible links between these categories of ecosystem functions and groups of ecosystem services (by a panel scientific experts in various fields of environmental sciences) then finds that these direct and indirect linkages still need clarification. We illustrate how the proposed framework could be used on terrestrial microalgae and cyanobacteria to assess the potential effects of herbicides on ecosystem services. The framework proposed here uses a set of clearly-defined core categories of ecosystem functions and services, which should help identify which of them are effectively or potentially threatened by PPP. We argue that this framework could help harmonize and extend the scientific knowledge that informs decision-making and policy-making.

L’Ifremer coordonne, sur l’ensemble du littoral métropolitain, la mise en œuvre des réseaux d’observation et de surveillance de la mer côtière. Ces outils de collecte de données sur l’état du milieu marin répondent à deux objectifs : • servir des besoins institutionnels en fournissant aux pouvoirs publics des informations répondant aux exigences de la Directive Cadre sur l’Eau (DCE), des conventions de mers régionales (OSPAR et Barcelone) et de la réglementation sanitaire relative à la salubrité des coquillages de production conchylicoles ou de pêche ; • acquérir des séries de données nourrissant les programmes de recherche visant à mieux comprendre le fonctionnement des écosystèmes côtiers et à identifier les facteurs à l’origine des changements observés dans ces écosystèmes. Le dispositif comprend : le réseau d’observation et de surveillance du phytoplancton et de l’hydrologie dans les eaux littorales (REPHY), le réseau de surveillance des phycotoxines dans les organismes marins (REPHYTOX), le réseau d’observation de la contamination chimique (ROCCH), le réseau de contrôle microbiologique (REMI) et les réseaux de surveillance benthique pour la DCE (DCE Benthos). Les Laboratoires Environnement et Ressources (LER) de l’Ifremer opèrent également des observatoires de la ressource conchylicole : ECOSCOPA pour l’huitre creuse, MYTILOBS pour la moule bleue. Toutes les données obtenues intègrent la base de données Quadrige² qui est le référentiel national des données de la surveillance des eaux littorales et forme une composante du Système national d’information sur l’eau (SIEau). Le bulletin de la Qualité Littoral du Laboratoire Environnement Ressources du Languedoc-Roussillon (LER/LR) contient une synthèse et une analyse des données collectées par l’ensemble des réseaux pour la région Occitanie en 2020. Des représentations graphiques homogènes pour tout le littoral français, assorties de commentaires, donnent des indications sur les niveaux et les tendances des paramètres mesurés sur les bandes littorales et dans les lagunes des départements des Pyrénées Orientales, de l’Aude, de l’Hérault, du Gard.

Oysters modify the planktonic microbial community structure by their filtration and NH4 excretion activities. While many studies have been conducted on this subject with adult oysters, none had been carried out in situ with juveniles. Pacific oyster juveniles (Magallana gigas, previously Crassostrea gigas) died massively all over the world since 2008 in relation with OsHV-1 infection. During mortality episodes, sick and dead oysters are not separated from healthy live ones, and left to decay in the surrounding environment, with unknown consequences for the nutrient cycle and planktonic microbial components (PMC). The present study aimed to elucidate for the first time the interactions between oyster juveniles and PMC during a mortality episode. Innovative 425-L pelagic chambers were deployed weekly in situ around oyster lanterns along a stocking-density gradient in the Thau Mediterranean lagoon (France) before, during and after an oyster mortality episode, from April to May 2015. This study reveals (i) significant changes of planktonic microbial community structure during mortality episodes, with a proliferation of picoplankton (

WOS:000674222500001; Pharmaceuticals are present in natural waters, thus contributing to the general exposure of aquatic organisms, but few data are available on the accumulation of these substances in marine organisms. The present study evaluated the in vivo bioconcentration of an antidepressant-venlafaxine (VLF)-in marine mussels (Mytilus galloprovincialis) during 7 days of exposure at nominal 10 mu g/L concentration, followed by a 7-day depuration period. The bioconcentration factor (BCF) was 265 mL/g dry weight (dw). VLF accumulation reached an average tissue concentration of 2146 +/- 156 ng/g dw within 7 days, showing a first-order kinetics process. N-desmethylvenlafaxine (N-VLF) and O-desmethylvenlafaxine (O-VLF) metabolites were quantified in mussel tissues, whereas N,N-didesmethylvenlafaxine (NN-VLF) was only recorded as being detected. These three metabolites were also quantified in water, indicating an active metabolism and VLF excretion in Mediterranean mussels. Complementary experiments conducted at nominal concentrations of 1, 10, and 100 mu g/L for 7 days confirmed the VLF bioconcentration and metabolism and allowed us to quantify a supplementary metabolite, i.e., N,O-didesmethylvenlafaxine (NO-VLF), in mussel tissues. These results encourage further research on a more complete characterization of metabolism and on any disturbances linked to bioconcentration of VLF on bivalves.

International audience; The aim of the present work was to test the influence of juvenile oyster culture on benthic-pelagic coupling in the French Mediterranean Thau Lagoon. Although the period of juvenile growth induces the introduction of millions of juvenile oysters in the lagoon over a short duration, the effects on the water-column and on the benthic ecosystem are poorly known. Using a multiple ecological approach, water column parameters, sedimentation rates, sediment characteristics and benthic fluxes were monitored on three occasions during the oyster pre-growth period, from October to December, at two sites inside the farming area and two sites outside the farming area that served as reference. In the water column, results showed a significant lower ratio between total phytoplankton biomass (chlorophyll-a) and degraded pigments (pheopigment), a significant increase in the contribution of phytoplankton containing chlorophyll-b (ie chlorophytes) to total phytoplankton biomass and a significant decrease in the contribution of phytoplankton containing chlorophyll-c (mainly diatoms) to the total phytoplankton biomass at farm sites, attributed to the grazing pressure caused by juvenile oysters on large particles, as described for adult oysters. No significant effect was observed at the benthic interface during this period, due to the dispersion of the small quantities of biodeposit produced by juveniles in the low water temperature conditions. A multivariate approach supported the effect of juvenile oysters on the water column and revealed a trend in benthic conditions with farm sites being distinct from the reference ones. The long farming history of the lagoon could have shaped sediment properties such that farming areas maintain different benthic conditions.

Ce rapport a pour objet de faire le bilan de l'état de réalisation de l'étude : Suivi des lagunes du Bassin RMC - programme 2017-2019, Volet pesticide, ci après nommée "OBSLAG pesticides", et encadrée par les contrats Ifremer n°17/3212552/F et 18/1312605 et par les conventions d'aide financière avec l'AERMC n°2017 1182 et n°2017 1185 et dont le terme est prévu en février 2020.

French Mediterranean coastal lagoons have been subject to huge inputs of urban nutrients for decades leading to the eutrophication of these vulnerable ecosystems. In response to new environmental regulations, some of the lagoons have recently been the subject of large-scale management actions targeting the waste water treatment systems located on their watersheds. While the eutrophication of coastal ecosystems is well described, recovery trajectories have only recently been studied. To assess the rapidity and the extent of the effect of the remediation actions, we analysed data from a 14-year time series resulting from the monitoring of nutrients, biomass and the abundance of phytoplankton in the water column of French Mediterranean coastal lagoons covering the whole anthropogenic eutrophication gradient. Following a 50% to 80% reduction in total phosphorus (TP) and total nitrogen (TN) urban loadings from the watershed of hypertrophic and eutrophic ecosystems, the integrative parameters chlorophyll a, TN and TP, provide evidence for a rapid response (1 to 3 years) and for an almost complete recovery, suggesting no hysteresis for the eutrophic lagoon. However, our findings also show that recovery patterns depend on the eutrophication status before remediation and may include feedback responses. The different responses revealed by our results should help stakeholders prioritise remediation actions and identify appropriate restoration goals, especially in light of the targets of the Water Framework Directive (WFD).

International audience; Near-shore and direct groundwater inputs are frequently omitted from nutrient budgets of coastal lagoons. This study investigated groundwater-driven dissolved inorganic nitrogen (DIN) inputs from an alluvial aquifer to the hypertrophic Or lagoon, with a focus on the Salaison River. Piezometric contours revealed that the Salaison hydrogeological catchment is 42% bigger than the surface watershed and hydraulic gradients suggest significant groundwater discharge all along the stream. Hydrograph separation of the water flow at a gauging station located 3 km upstream from the Or lagoon combined with DIN historical data enabled to estimate that groundwater-driven DIN inputs account for 81–87% of the annual total DIN inputs to the stream upstream from the gauging station. A radon mass balance was performed for the hydrological cycle 2017–2018 to estimate groundwater inflow into the downstream part of the stream. Results showed that (1) DIN fluxes increased by a factor 1.1 to 2.3 between the gauging station and the Salaison outlet, (2) the increase in DIN was due to two groundwater-fed canals and to groundwater discharge along the stream, the latter represented 63–78% of the water flow. This study thus highlights the significance of groundwater driven DIN inputs into the Salaison River, which account for 90% of the annual DIN inputs. This is particularly true in the downstream part of the river, which, on averages, supplies 48% of total DIN inputs to the river. These downstream DIN inputs into the Or lagoon were previously not taken into account in the management of this and other Mediterranean lagoons. The inputs will probably affect restoration processes for many years due to their residence time in the aquifer. This study throws light on a rarely documented source of ‘very-nearshore’ groundwater discharge to coastal streams in water and nutrient budgets of coastal zone ecosystems.

International audience; Aquatic organisms are exposed to pharmaceuticals present in natural waters, but few data are available on the accumulation of these substances in such organisms. The present study evaluated the in vivo bioconcentration of two anticonvulsants – carbamazepine (CBZ) and 10-hydroxy-10,11-dihydro-carbamazepine (10OH) – in marine mussels (Mytilus galloprovincialis) exposed to nominal 10 μg L− 1 concentrations for one week. The bioconcentration factors (BCFs) were 3.9 and 4.5 L kg− 1 dry weight (dw) for CBZ and 10OH, respectively. CBZ accumulation reached an average tissue concentration of 29.3 ± 4.8 ng g− 1 dw, and 10OH accumulated up to 40.9 ± 4.6 ng g− 1 dw in tissues within one week, showing first-order kinetics. BCF obtained with linear QSAR models correctly estimated the CBZ bioconcentration and overestimated the 10OH bioconcentration to some extent. The detection of two metabolites (carbamazepine-10,11-epoxide and acridine) among the five sought suggested an active metabolism for CBZ. In contrast, none of the 10OH metabolites were detected in mussels exposed to 10OH. CBZ showed higher accumulation in the digestive gland, where some relevant metabolites were detected, than in other studied tissues. The implication of those findings on field biomonitoring is discussed.

International audience; Ostreid herpesvirus 1 (OsHV-1 μvar) infection has caused significant mortalities in juvenile oysters (Crassostrea gigas). In contrast to the practices of other animal production industries, sick and dead oysters are not separated from live ones and are left to decay in the surrounding environment, with unknown consequences on fluxes of dissolved materials. A laboratory approach was used in this study to test the influence of oyster mortality episode on dissolved inorganic fluxes at the oyster interface, dissociating (i) the effect of viral infection on metabolism of juvenile oysters and (ii) the effect of flesh decomposition on oxygen consumption and nutrient releases at the individual scale. Nine batches of juvenile oysters (Individual Total wet weight 1 g) were infected via injection of OsHV-1 enriched inoculums at different viral loads (108 and 109 OsHV-1 DNA copies per oyster) to explore infection thresholds. Oysters injected with filtered seawater were used as controls (C). Oysters were maintained under standard conditions to avoid stress linked to hypoxia, starvation, or ammonia excess. Before, after the injection and during the mortality episode, i.e. at days 1, 3, 7, 10 and 14, nine oysters per treatment were incubated in individual metabolic chambers to quantify oxygen, ammonium and phosphate fluxes at the seawater-oyster interface. Nine empty chambers served as a reference. Injections of the two viral loads of OsHV-1 induced similar mortality rates (38%), beginning at day 3 and lasting until day 14. The observed mortality kinetics were slower than those reported in previous experimental pathology studies, but comparable to those observed in the field (Thau lagoon, France). This study highlights that oxygen and nutrient fluxes significantly varied during mortality episode. Indeed (i) OsHV-1 infection firstly modifies oyster metabolism, with significant decreases in oxygen consumption and ammonium excretion, and (ii) dead oysters lead to a strong increase of ammonium (6 fold) and phosphate (41 fold) fluxes and a decrease in the N/P ratio due to mineralisation of their flesh. The latter may modify the structure of the planktonic community in the field during mortality episode. This study is a first step of the MORTAFLUX program. The second step was to in situ confirm this abnormal nutrient loading during a mortality episode and show its impact on bacterio-, phyto- and protozoo-plankton.

International audience

Coastal areas are subject to growing pressures and impacts due to increasing of the human activities. Lipophilic organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) or polychlorinated biphenyls (PCBs), have been monitored for decades within biomonitoring programs. However, until now, little information on the detection of called “emerging contaminants” as hydrophilic organic compounds, in the marine environment and no data on its metabolites or transformation products in marine organisms is available. In this way, a sensitive analytical methodology for identification and confirmation of venlafaxine residues (VEN) and five of its main metabolites in the marine mussels Mytilus galloprovincialis was validated. The sample preparation procedure was based on the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) approach. An analytical method was then developed to quantify these compounds at ultra-trace levels by liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS). The strategy was then applied to marine mussels collected from Mediterranean Sea in southeastern France. Residues of the antidepressant VEN were occasionally detected at ng/g dw level. In addition, the approach allowed us to identify and quantify several transformation products in the analyzed samples. N-Desmethylvenlafaxine (NDV) was the most frequently detected metabolite followed by N,O-Di-Desmethylvenlafaxine (NODDV) and O-Desmethylvenlafaxine (ODV).

International audience; Along the French Mediterranean coast, a complex of eight lagoons underwent intensive eutrophication over four decades, mainly related to nutrient over-enrichment from continuous sewage discharges. The lagoon complex displayed a wide trophic gradient from mesotrophy to hypertrophy and primary production was dominated by phytoplankton communities. In 2005, the implementation of an 11 km offshore outfall system diverted the treated sewage effluents leading to a drastic reduction of anthropogenic inputs of nitrogen and phosphorus into the lagoons. Time series data have been examined from 2000 to 2013 for physical, chemical and biological (phytoplankton) variables of the water column during the summer period. Since 2006, total nitrogen and phosphorus concentrations as well as chlorophyll biomass strongly decreased revealing an improvement in lagoon water quality. In summertime, the decline in phytoplankton biomass was accompanied by shifts in community structure and composition that could be explained by adopting a functional approach by considering the common functional traits of the main algal groups. These phytoplankton communities were dominated by functional groups of small-sized and fast-growing algae (diatoms, cryptophytes and green algae). The trajectories of summer phytoplankton communities displayed a complex response to changing nutrient loads over time. While diatoms were the major group in 2006 in all the lagoons, the summer phytoplankton composition in hypertrophic lagoons has shifted towards green algae, which are particularly well adapted to summertime conditions. All lagoons showed increasing proportion and occurrence of peridinin-rich dinophytes over time, probably related to their capacity for mixotrophy. The diversity patterns were marked by a strong variability in eutrophic and hypertrophic lagoons whereas phytoplankton community structure reached the highest diversity and stability in mesotrophic lagoons. We observe that during the re-oligotrophication process in coastal lagoons, phytoplankton shows complex trajectories with similarities with those observed in freshwater lake systems.

International audience; A significant investment in research has been conducted to define exposures andpotential hazards of pharmaceuticals in freshwater and terrestrial ecosystems. Incontrast, comparatively few empirical studies have been conducted forpharmaceuticals that are likely to enter coastal and marine ecosystems[1,2]. Theantidepressant venlafaxine (VLF) and some of its metabolites were recently foundin mussels caged in a coastal site receiving treated wastewater[3]. In those marineorganisms, very scarce data is available on the accumulation and/or metabolisationof pharmaceuticals. Consequently, it appears hazardous to conclude on the originof those metabolites in mussels, which could include a bioaccumulation throughdirect exposure as well as a metabolism of VLF in mussels. The aim of the presentwork was to quantify the accumulation of VLF in the marine mussel Mytilusgalloprovincialis and to evaluate the possible metabolism in laboratory controlledexperiments. The accumulation of VLF was evaluated in the whole mussel tissuesafter 1, 3 and 7 days of semi-static exposure by water (10µg L-1day-1) followedby 1, 3 and 7 days of depuration. Under those conditions, VLF attained an averagetissue concentration of (n=3) 2146.3 ± 156.0 ng g-1 dry weight (d.w.) in sevendays. The kinetic bioconcentration factor (BCF) was 265 ± 19 L kg-1 d.w. Sevendays of depuration allowed a decrease of tissue concentration to 21 ± 1.0 ng g-1d.w. Four VLF metabolites were quantified in mussel tissues and excreted inwater. The kinetics of those metabolites in water confirmed the metabolism ofVLF by mussels. Complementary experiment conducted at 1, 10 and 100 µL L-1nominal concentration clearly confirmed that M. galloprovincialis metabolizeVLF, with the quantification of studied metabolites excepted the NNO-VLF.These results gave a first approach on the ability of mussel to metabolizepharmaceuticals. Together with bioaccumulation information, this study provideda first approach on the pharmacokinetics of a pharmaceutical in a wild marinespecies, underlining the need of further experiments to better understand howvenlafaxine modulate the receptors in mussels and how exposure to thisantidepressant affects physiological functions of invertebrates.

International audience; In the last years, several scientific studies have shown that carbamazepine (CBZ) is one of the most frequently detected pharmaceutical in aquatic environment. However, little data is available on its detection and its transformation products (TPs) in marine water. The use of polar organic chemical integrative sampling (POCIS) passive samplers as a semi-quantitative and qualitative tool for screening of pharmaceuticals and TPs in seawater has been studied. Furthermore, the uptake rates of the target compounds were also determined under laboratory experiments to characterize the levels accumulated in devices. The results confirmed the presence of residues of anticonvulsant CBZ as well as some of its main metabolites, over a 1-year monitoring campaign carried out in French coast on the Mediterranean Sea. The work reports for the first time the presence of two TPs (10,11-dihydro-10,11-trans-dihydroxycarbamazepine (TRANS) and 10-hydroxy-10,11-dihydrocarbamazepine (10OH)) in marine water. The results contribute in assessing the environmental and human health risk of pharmaceuticals on coastal areas.

International audience; The accumulation of EHMC, OCT and OD-PABA, three common UV filter compounds, was investigated in marine mussels. Wild Mytilus edulis and Mytilus galloprovincialis were sampled in ten sites along the French Atlantic and Mediterranean coasts from June to November. In mussel tissues, 100% of the samples had quantifiable EHMC concentrations ranging from 3 to 256 ng g− 1 dry weight, while 55% of the samples had detectable OCT concentrations ranging from under 2 to 7 112 ng g− 1 dry weight. These concentrations significantly increased with the rising air temperature in summer, the recreational pressure and the geomorphological structure of the sampling sites (its lack of openness to the wide). This is the first study to report bioaccumulation of UV filters in marine mussels, thus highlighting the need for further monitoring and assessment.

International audience; Parent compounds and metabolites excreted in wastewater are inconstantly eliminated in WTPs and therefore are rejected mainly in surface water. However, the coastal environment suffers from pollution generated by inland activities which discharge their wastes into the sea via streams, rivers and wastewater marine outfalls. The low levels reported in the marine environment encourage the development of adapted methodologies to estimate predicted environmental concentrations (PECs). In the present work, the occurrence of VLF and its major human metabolites was investigated at a Mediterranean coastal site directly impacted by a submarine outfall. Concentrations of VLF and its metabolites were measured in the different compartments i.e. in water with passive sampler, sediment and mussels. Predicted concentrations of VLF and its main human metabolites were estimated in seawater taking into account the sold amounts of VLF, its human metabolism and the diffusion and dilution of the compounds in the coastal zone using an adapted hydrodynamic model (MARS 3D) developed by Ifremer. In seawater, estimated concentrations were in a good agreement with measured levels. Moreover, concentrations in mussels were estimated using concentrations estimated in seawater and a bioconcentration factor (BCF) linear model described in the literature for marine mussels. Estimated concentrations in biota were then compared to the concentrations in mussels detected at the studied site. Concentrations estimated with the BCF model were overestimated compared to measured concentrations, which could be explained by a possible metabolism of these compounds by mussels, not taken into account in the estimations. Moreover, attenuation mechanisms such as sorption on suspended matter could explain a lower availability of compounds for mussels in the water column and a lower bioconcentration in organisms than those expected. Studies on sorption mechanismsand metabolism of these compounds in mussels should be further performed, in order to improve these estimations. As organisms are long-term exposed to low concentrations of pharmaceuticals, possible effects could be observed. The use of sensitive approaches, such as “omics” approaches, already used for other pollutants such as heavy metals, could help obtain this information.

L’objectif de cette étude est de mettre en évidence et de hiérarchiser les pressions anthropiques ayant le plus d’impact sur les éléments de qualité DCE sur les lagunes méditerranéennes et de consolider ainsi les liens état/pressions. Il s’agit également de mettre en évidence des groupes de masses d’eau homogènes en termes de pressions. Ce travail s’appuie sur les précédentes études menées sur le sujet (Battut, 2010 ; Bouchoucha et al., 2010 ; Meinesz et al., 2013) et vise à les compléter grâce : • à la mise en œuvre d’une approche descriptive multidimensionnelle qui permet de mettre en évidence les interactions entre les différentes métriques de pression et d’état et de regrouper les masses d’eau similaires, • à l’intégration de données de pression et d’état complémentaires : pressions hydromorphologiques (Aquascop, 2014), état biologique (campagnes DCE 2009 et 2012), contamination chimique de l’eau et du biote (PEPSLAG 2010, DCE 2012, RINBIO 2009 et RINBIO 2012), • à la mis en œuvre d’une méthode de hiérarchisation permettant de faire un tri parmi les 81 métriques analysées. Les analyses réalisées sur les variables hydromorphologiques permettent de consolider l’intérêt d’un découpage de la typologie des lagunes, du fait de la spécificité des masses d’eau oligohalines et mésohalines. Pour les lagunes poly-euhalines, les analyses mettent en évidence des groupes de masses d’eau différents selon l’ensemble de variables pris en compte. Les variables de pressions font ressortir un gradient de pressions anthropiques, auquel les rejets des stations d’épuration contribuent le plus fortement. Un gradient de « bon état » est par ailleurs mis en évidence par les indicateurs biologiques et physico-chimiques. Les indicateurs écologiques les plus fortement corrélées aux variables hydromorphologiques et de pression sont la turbidité, le NID, la composition des macrophytes et l’état du phytoplancton. L’écart de salinité moyen entre la mer et la lagune ressort comme la variable la plus anti-corrélée aux variables d’état écologique. Ensuite, les pressions urbaines et les stocks sédimentaires de phosphore apparaissent fortement liés aux indicateurs d’état écologique. Les données de contamination chimique des moules permettent de distinguer un gradient de pollution organique et métallique, auquel contribuent fortement les concentrations en PCB, DDT, HAP, mercure et plomb. Les pressions urbaines et agricoles apparaissent comme les variables les plus corrélées aux concentrations de ces 5 contaminants dans le biote. En revanche, les analyses des données d’état chimique de l’eau évalué au travers d’échantillonneurs passifs illustrent les fortes disparités entre les résultats des campagnes 2010 et 2012 et mettent en évidence peu de liens avec les variables hydromorphologiques et de pressions.

International audience

In vitro bioassays would facilitate monitoring of estrogen-like compounds in mussels (Mytilus galloprovincialis) since they tend to accumulate lipophilic compounds in their fat and muscle tissue. However, estradiol (E2) steroid (already identified in mussels) could induce false positive responses. This study focuses on temporal variability in estrogenic responses of mussel extracts and the possible relation of this response with E2 levels. The reproductive cycle and growth were thus monitored for six months in sexed mussels. E2 levels were similar between genders and these levels varied with reproductive stages. human estrogen receptor (hER) activities were similar at all stages except in February. E2 present in male and female extracts accounted for part of the hER activation observed, but no correlation was found between E2 levels and hER activities. (C) 2008 Elsevier Ltd. All rights reserved.

The Water Framework Directive (WFD) is probably the most significant legislation in the water field that has been introduced for many years. Several publications pointed out that passive samplers (PSs) can be valuable tools as complementary method in monitoring water quality in the context of the WFD However, there is still a lack of quality assurance and control (QA/QC) procedures that demonstrate the reliability and the comparability of results obtained by passive sampling. Up to date, very few in situ intercomparison exercises on PSs have been performed until now. To our knowledge only three pan-European or international intercomparison studies have been organized in situ since 2007 (ICES Passive sampling survey and intercalibration, AQUAREF, IPSIC and NORMAN). Among them, the AQUAREF intercomparison exercise was conducted on several passive samplers for priority pollutants (PAH, pesticides and metals) in surface and coastal waters. Presentation of this exercise and first outputs have been already published (Miège et al., 2012) and showed that in spite of variety of expert laboratories, strategies and tools, we observed a low and satisfactory uncertainty on the estimation of mean TWA concentrations with passive sampling. The objective of this poster is to present specific results obtained during this interlaboratory exercise for pesticide sampling. Two trials were conducted during 14 days in the Charente River (at Beillant, France) and in a marine site, the Thau Lagoon (Hérault, France) with the participation of 11 laboratories at Beillant and 8 laboratories at Thau. Nine pesticides (acetochlor, S-metolachlor, 5 WFD priority substances, i.e., alachlor, atrazine, diuron, isoproturon, simazine and two atrazine metabolites, i.e. desethylatrazine, deisopropylatrazine) were considered. Among the tested PSs, we found Polar Organic Chemical Integrative Sampler (POCIS, pharmaceutical & pesticide configuration), polar Chemcatcher (with SDB-XC, SDB-RPS or C18 phases), silicon rod and silicon sheet, speedisk hydrophylic DVB06, ... We will present here and discuss results on i) Comparison of pesticide quantities accumulated per surface of passive sampler exposed ii) Mean and variability of Time Weighted Average (TWA) water concentrations of pesticides obtained with passive samplers and comparison with water concentration from grab samples iii) Pesticide fingerprints in the various passive samplers compared with those in grab samples

International audience; To assess pharmaceutical contamination in surface waters at a national and regional scale, different geo-referenced watershed models PhATETM and GREAT-ER were used. These models incorporate spatial and temporal characteristics of the receiving environment allowing more accurate and realistic PECs than those calculated according to EMEA guidelines methodology. In coastal zone, models including the diffusion are scarce; however, this interface between the land and the sea should also been affected by drugs contamination.Thus, the aim of the present project is to propose a model to assess pharmaceuticals concentrations in a coastal zone receiving effluents from a WTP through a submarine outfall. For this purpose, pharmaceuticals, carbamazepine (Cbz), oxcarbazepine (OxCz) and their main metabolites were selected. In effluents, PECs calculation took into account in addition to the common wastewater fate, the initial Cbz and OxCz prescriptions, their metabolisms and their excretion rates. The obtained PECs results were similar to the measured concentrations (MECs) in the wastewater effluent. In the coastal zone, PECs were calculated taking into account the diffusion in the coastal zone through the submarine outfall using the hydrodynamic numeric model MARS 3D. PEC values in coastal zone were in agreement with MECs, measured using the passivesamplers polar organic chemical integrative sampler implemented around the submarine outfall. The combined approach considering both detailed local consumption of parent compounds and their human metabolisms, in association with the diffusion estimation in coastal water allowed a reliable estimation of the pharmaceutical PEC for parent compounds and metabolites. MARS 3D model allows a refined assessment of concentrations in seawater influenced by specific mechanisms occurring. It can be further applied to others molecules, including elimination half-lives.

21 pharmaceuticals, 6 alkylphenols and 27 hydrophilic pesticides and biocides were investigated using polar organic contaminant integrative samplers (POCIS) during a large-scale study of contamination of French Mediterranean coastal waters. Marine and transitional water-bodies, defined under the EU Water Framework Directive were monitored. Our results show that the French Mediterranean coastal waters were contaminated with a large range of emerging contaminants, detected at low concentrations during the summer season. Caffeine, carbamazepine, theophilline and terbutaline were detected with a detection frequency higher than 83% in the coastal waters sampled, 4-nonylphenol (4-NP), 4-tert-octylphenol (4-OP) and 4-nonylphenol diethoxylate (NP2EO) were detected in all coastal waters sampled, and diuron, terbuthylazine, atrazine, irgarol and simazine were detected in more than 77% of samples. For pharmaceuticals, highest time-weighted average (TWA) concentrations were measured for caffeine and carbamazepine (32 and 12 ng L-1, respectively). For alkylphenols, highest TWA concentrations were measured for 4-nonylphenol mono-ethoxylate and 4-nonylphenol (41 and 33 ng L-1, respectively), and for herbicides and biocides, they were measured for diuron and irgarol (33 and 2.5 ng L-1, respectively). Except for Diana lagoon, lagoons and semi-enclosed bays were the most contaminated areas for herbicides and pharmaceuticals, whilst, for alkylphenols, levels of contamination were similar in lagoons and coastal waters. This study demonstrates the relevance and utility of POCIS as quantitative tool for measuring low concentrations of emerging contaminants in marine waters.

Bioaccumulation is essential for gaining insight into the impact of exposure to organic micropollutants in aquatic fauna. Data are currently available on the bioaccumulation of persistent organic pollutants, but there is very little documentation on the bioaccumulation of pharmaceuticals and personal care products (PPCPs). The bioconcentration of selected PPCPs was studied in marine mussels (Mytilus galloprovincialis). The selected PPCPs were two organic UV filters, i.e., 2-ethylhexyl-4-trimethoxycinnamate (EHMC) and octocrylene (OC), and two benzodiazepines (BZP), i.e., diazepam (DZP) and tetrazepam (TZP). Laboratory experiments were performed in which M. galloprovincialis was exposed to these compounds either directly from water, for the less lipophilic substances (BZP) or via spiked food for lipophilic UV filters. M. galloprovincialis uptook and eliminated BZP following first-order kinetics. The biological half-life (t (1/2)) of TZP was 1.4 days, resulting in a bioconcentration factor of 64 and 99 mL g(-1) dry weight (dw), respectively, for 2.3 and 14.5 μg L(-1) of exposure, while the biological half-life (t (1/2)) of DZP was 0.4 days, resulting in a bioconcentration factor of 51 mL g(-1) dw for 13.2 μg L(-1) of exposure. The uptake of UV filter was rapid in mussels, followed by elimination within 24 h. EHMC increased from 15 to 138 ng g(-1) dw in 1 h and decreased to 25 ng g(-1) after 24 h for 11.9 μg L(-1) exposure. OC reached 839 ng g(-1) dw after 1 h and decreased to 33 ng g(-1) after 24 h for 11.6 μg L(-1) exposure. However, EHMC and OC were slightly accumulated in 48 h, i.e., 38 and 60 ng g(-1) dw, respectively.

Pharmaceuticals are widely released in aquatic environment through treated wastewaters. They reach coastal zone indirectly via streams or directly though marine outfalls however data concerning this contamination in coastal waters are scarce. Environmental Risk Assessment (ERA) of pharmaceuticals have been conducted mostly in surface waters and has not been performed in coastal zone. The first step of ERA is to evaluate the exposure through predictive environmental concentration (PEC) values. The aim of this study was to predict the occurrence of some pharmaceuticals in a coastal aera subjected to treated wastewater (TWW) reject through a marine outfall (Fig 2.). Among pharmaceuticals, Carbamazepine, Oxcarbazepine and their main metabolites (Fig 1.) were chosen. CBZ has been proposed as an indicator of wastewater contamination and has been already detected in Mediterranean (Munaron et al., 2011). Prediction was performed based on local pharmaceuticals consumption recording and a review of pharmacokinetics data. PECs values were estimated in TWW and at the marine outfall and compared with MECs obtained by direct quantification and with POCIS implementation.

Dans le périmètre de la Directive Cadre Européenne sur l’Eau (DCE), une campagne menée entre mars et avril 2009 (N.O. "L’Europe") a permis d'évaluer la qualité des eaux côtières méditerranéennes françaises. Les objectifs étaient de compléter les résultats acquis en 2006, de déterminer, grâce en grande partie à la mise en oeuvre de stations artificielles de moules (réseau RINBIO), la contamination chimique de l’eau. Afin de pouvoir mesurer les concentrations de contaminants chimiques (métaux composés organiques hydrophobes et hydrophiles), des échantillonneurs passifs (DGT, SBSE et POCIS) ont également été utilisés au cours de cette campagne. Les données obtenues ont contribué à la caractérisation des masses d'eau par rapport à certains contaminants sur lesquels il n'y avait aucune information, à la mise en évidence de la présence, ou l’absence, de certains contaminants émergents. De plus, les concentrations mesurées ont permis de définir les niveaux moyens d’exposition pour l'ensemble des contaminants suivis, notamment ceux faisant partie des listes prioritaires des annexes IX et X de la DCE. Les données obtenues ont aussi permis de compléter celles de la première campagne PEPS Méditerranée réalisée en 2008 au cours de laquelle des mesures de concentrations de métaux et de composés hydrophiles avaient été réalisées grâce à des DGT et des POCIS (Gonzalez et al., 2009b).

Ce document est réalisé dans le cadre de la convention Onema-Ifremer 2010 au titre de l’action n°9 (Mise en place d’un site « marin » en Méditerranée pour l’essai inter-laboratoire (EIL) sur les échantillonneurs passifs). Cette action s’inscrit dans le programme AQUAREF 2010 et vient donc en complément de l’action n°13 de la convention Onema- Cemagref 2010 (Exercices d’inter-comparaison in situ d’échantillonneurs intégratifs. Application pour l’échantillonnage de métaux, d’hydrocarbures aromatiques polycycliques et de pesticides). Sur le fond, ces deux actions ne peuvent être dissociées, c’est pourquoi les deux rapports d’étape réalisés (dont celui-ci) présenteront inévitablement des redondances. Les difficultés liées à la mesure de micropolluants dans les eaux marines ont conduit au développement de divers systèmes d’échantillonnage in situ (échantillonneurs passifs) dans le but de faciliter la représentativité de l'échantillonnage et la détection des micropolluants à l’état de traces. De nombreux laboratoires de recherche les utilisent c’est pourquoi un besoin d’harmonisation et de synthèse des pratiques est devenu indispensable pour améliorer et développer l’usage de ces outils notamment dans l’optique de suivis environnementaux réglementaires (DCE, DCSMM). Le présent rapport synthétise les résultats de l'organisation d'un essai d’intercomparaison sur ces nouveaux outils pour l'échantillonnage de substances prioritaires de la DCE dans les eaux marines de l’étang de Thau. Cet EIL s’intègre dans une démarche plus large initiée dans le cadre d’AQUAREF et coordonnée par le Cemagref, dans le cadre de laquelle deux sites « eaux douces » ont également fait l’objet d’intercomparaisons. Les résultats de ces trois essais sont actuellement en cours de traitement par le comité d’organisation, de manière conjointe en parallèle. Ils ne seront donc pas présentés ici.

Le RSL véritable outil de veille et d’aide à la décision, produit chaque année un diagnostic des lagunes de la Région Languedoc-Roussillon vis-à-vis de l’eutrophisation.Il permet ainsi d’alimenter les réflexions dans le cadre des démarches de gestion concertée, d’orienter la mise en œuvre d’action et les travaux de restauration prioritaires.

International audience; The use of mussel extracts in in vitro bioassays which express the estrogen receptor could provide valuable information on the bioavailability of endocrine disruptors in coastal environments. The aim of this study was to assess the temporal variability of the estrogenic responses in bioassays in Mytilus galloprovincialis. A 6-month in situ experiment was conducted in order to follow the estrogenic activity on MELN cell line during the reproduction stages of mussels. Estradiol equivalents (EEQ) determined in mussels using the MELN cell lines ranged from 0.79 to 3.72 ng/g dry weight (d.w.) in males, from 0.42 to 2.33 ng/g d.w. in females and from 3.41 to 4.2 d.w. in undifferentiated bivalves. We observed an increase in EEQ values during the spawning stage for males, not for female. The maximal EEQ values were observed at the indifferent stage. We discuss these results in regards to the actual knowledge on mussels' reproductive cycle and to the possible impact of xeno-estrogens. Variations of E2 levels in mussels must be taken into account for further studies on xeno-estrogens monitoring using hER reporter cell-lines bioassays.

In order to better understand environmental disturbances in the French coastal Mediterranean lagoons, we used an ecotoxicological approach based on the measurement of the toxicity of the sediments using oyster embryo bioassay that provides a basis for assessing the effects on the fauna of contaminants adsorbed on the sedimentary particles. The study covers all of the main lagoons of the French Mediterranean coasts of Languedoc Roussillon, Camargue, and Provence (Berre and Bolmon lagoons), where 188 stations were sampled. The toxicity tests provide evidence of variable levels of toxicity in sediments. Contaminated lagoons such as La peyrade, Le canet, and Ingrill and locally affected lagoons such as Bages-Sigean, Vaccares, Bolmon, and Berre have sampling stations with 100% of larval abnormalities during 24-h development. In all of the lagoons, the toxicity was mainly located close to local harbors and rivers. Salses Leucate (Languedoc roussillon) lagoon was found very clean, with no important toxicity. The results are discussed in terms of environmental disturbances of the coastal lagoons and with regard to the long-term monitoring of the impact of contaminants on the coastal environment.

Our study aims at making progress the estimate of herbicide and nutrient inputs to the Marennes-Oleron bay which could influence summer oysters mortalities, and to bring a better understanding of the impact on coastal ecosystems by modelling the dynamics of these compounds in the shellfish-farming area. The development of a strategy adapted to the river Charente and its estuary reveals that agricultural activity on the watershed area is omnipresent, as well on the level of the nitrogen as on the one of herbicides contributions. It is thus necessary to specify Charente fluxes, which is the main tributary of the Marennes-Oleron bay, in order to better characterize its impact on shellfish-farming activity. Hydrodynamic modelling will constitute an invaluable help in the risk assessment with respect to pesticides, by specifying the periods of the high and low concentrations of these molecules and the biotope exposure durations., Cette étude vise à faire progresser l'estimation des apports d'herbicides et de nutriments au bassin de Marennes-Oléron susceptibles d'influencer les épisodes de mortalité estivale des huîtres, et à apporter par la modélisation une meilleure compréhension de la dynamique de ces composés dans la zone de production conchylicole. La mise au point d'une stratégie d'étude adaptée au fleuve Charente et à son estuaire révèle que l'influence de l'activité agricole sur le bassin versant est omniprésente, tant au niveau des apports d'azote que d'herbicides. Il est donc nécessaire de préciser les flux apportés par la Charente, principal affluent du bassin de Marennes-Oléron, afin de mieux caractériser son impact sur l'activité conchylicole. L'utilisation d'un modèle de dispersion constituera une aide précieuse dans l'évaluation du risque vis à vis des produits phytosanitaires, en précisant les niveaux de présence de ces molécules et les durées d'exposition du biotope.

Ce rapport a pour objet de faire le bilan de l'état de réalisation de l'étude : Suivi des lagunes du Bassin RMC - programme 2017-2019, Volet pesticide, nommée "OBSLAG pesticides", et encadrée par les contrats Ifremer n°17/3212552/F et 18/1312605 et par les conventions d'aide financière avec l'AERMC n°2017 1182 et n°2017 1185 et dont le terme est prévu en février 2020.

Since recent decades, nutrient-related eutrophication, originating from agricultural use of fertilizer and population enhancement, can be considered worldwide as the main disturbance for coastal lagoons. Since coastal lagoons are very shallow and enclosed, their functioning is tightly linked to meteorological conditions. The aim of this study is to compare different rainfall levels and eutrophication response on coastal lagoons of the Languedoc-Roussillon (Western Mediterranean coast), subject to different nutrient loads from their watershed, in order to check the possibility to distinguish the effects of watershed management or rainfall conditions on water quality (waste water treatment plant improvement, decrease of fertilizer spreading).

With the new European legislation (the Water Framework Directive, 2000/60/EC), the decision makers responsible for the assessment of the environmental contamination require simple monitoring tools. Passive sampling methods seem to be promising tools for the sampling of polar organic compounds in water, especially in marine waters where important dilutions and low concentrations are usual. They are taking into account the temporal variability and integrating the contamination over period of time. This work presents a study, on a large scale, of the contamination of French Mediterranean coastal waters realized in partnership with the Water Agency Rhône Méditerranée Corse (AERMC), and Coastal Water Quality Offices (CQEL).

This project is a contribution to the improvement and development of passive sampling techniques. The objectives are: - to develop ways to limit the fouling formation on the samplers requiring prolonged immersion time (POCIS) and ensure a "constant" and reproducible sampling rate - test and validate the DGT developed specifically for Hg wich is a "WFD priority" metal. Key words (thematic and geographical area) :Passive samplers, POCIS, DGT, fouling, sampling rate, Hg, baie du Lazaret , étang de Thau, Ce projet est une contribution à l'amélioration et au développement des techniques d'échantillonnage passif. Les objectifs sont: - de trouver des solutions pour limiter la formation de fouling sur les échantillonneurs nécessitant des temps d'immersion prolongés (POCIS) et assurer taux d'échantillonnage "constant" et reproductible. - de tester et valider les DGT développés spécialement pour Hg qui est un métal "DCE prioritaire" Mots clés (thématique et géographique) :Echantillonneurs passifs, POCIS, DGT, fouling, taux d'échantillonnage, Hg, baie du Lazaret , étang de Thau

L’Ifremer coordonne, sur l’ensemble du littoral métropolitain, la mise en œuvre des réseaux d’observation et de surveillance de la mer côtière. Ce bulletin contient une synthèse et une analyse des données collectées par l’ensemble des réseaux : de contrôle microbiologique (REMI), d’observation et de surveillance du phytoplancton et de l’hydrologie dans les eaux littorales (REPHY), de surveillance des phycotoxines dans les organismes marins (REPHYTOX), d’observation de la contamination chimique (ROCCH), d’observations conchylicoles (ECOSCOPA) des départements des Pyrénées Orientales, de l’Aude, de l’Hérault, du Gard du littoral de la région Occitanie en 2021. Des représentations graphiques homogènes, assorties de commentaires, donnent des indications sur les niveaux et les tendances des paramètres mesurés.

Cette étude est réalisée dans le cadre du projet OBSLAG (OBServatoire des LAGunes) et porte sur les 10 masses d’eau lagunaires méditerranéennes situées à l’aval des cours d’eau suivis depuis 2015 par le « réseau flux » de l'Agence de l’Eau Rhône Méditerranée Corse. Le rapport correspond aux actions réalisées en 2020 dans le cadre du volet « eutrophisation » d’OBSLAG, répondant aux objectifs suivants : (1) réaliser un suivi estival en 2020 du phytoplancton et de la physico-chimie de l’eau et évaluer l’état DCE de ces compartiments pour la période 2015-2020 sur les 10 masses d’eau lagunaires du suivi « réseau flux », regroupant 13 lagunes poly-euhalines. Ce suivi permet de renforcer la fréquence des suivis DCE sur la colonne d’eau et le phytoplancton, qui ne sont réalisés qu’un été sur deux depuis 2015 ; (2) appliquer des indicateurs plus sensibles que les indicateurs DCE, mettant en évidence, sur les périodes d’évaluation, les tendances d’évolution et la variabilité de l’état du phytoplancton et de la colonne d’eau, compartiments les plus réactifs des écosystèmes lagunaires. Les suivis réalisés au cours de l’été 2020 sur les 10 masses d’eau lagunaires ont montré que le bon état DCE est atteint pour la période 2015-2020 pour 6 masses d’eau en ce qui concerne les paramètres physico-chimiques de la colonne d’eau et pour 5 masses d’eau en ce qui concerne le compartiment phytoplancton. Quatre masses d’eau atteignent le bon état pour les deux compartiments colonne d’eau et phytoplancton (Bages-Sigean, Ayrolle, Thau et Berre). Une masse d’eau est concernée par une perte de classe qualité (La Palme en état moyen pour l’état physico-chimique) pour la période 2015-2020 par rapport à la période 2013-2018 et deux masses d’eau par des gains de classe de qualité (Berre en très bon état physico-chimique et en bon état pour le phytoplancton ; Canet en état médiocre pour le phytoplancton). L’application de méthodes statistiques adaptées (bootstrap, tests de Mann Kendall et de Kruskal-Wallis) sur les données acquises de 2015 à 2020 ont permis :  d’évaluer la confiance accompagnant les diagnostics DCE des masses d’eau,  de mettre en évidence une tendance à l’augmentation au cours de la période 2015-2020 des concentrations en nutriments sur 2 masses d’eau (La Palme et Thau) et une tendance à la diminution sur une masse d’eau (Palavasiens-Est),  de mettre en évidence une tendance à l’augmentation au cours de la période 2015-2020 de la biomasse de phytoplancton sur une masse d’eau (La Palme). Les indicateurs fournis permettent ainsi de détecter des changements de façon précoce et d’attirer l’attention sur des nouveaux signes de dégradation ou de restauration de l’état des lagunes.

The poster presents the approach that led to the construction of a network of cooperation between managers and scientists for coastal lagoon management in the region of Languedoc-Roussillon, its architecture and modus operandi, its achievements and developments over time. At the end of the ninety’s, eutrophication and lack of knowledge were identified as issues to enhance the management of coastal lagoons on the Mediterranean coast of France. In 2000, in the region of Languedoc-Roussillon, scientists (Ifremer) and institutional managers (Regional Council of Languedoc-Roussillon and Water Agency Rhône-Méditerranée & Corse) joined their forces in building a network to address this need. The core of this network consists of an operational tool for the diagnosis of eutrophication based on a battery of indicators within several ecological compartments of coastal lagoons (water column, phytoplankton, macrophytes, sediments). This tool routinely is operated at a regular time according to ecological compartments. The innovative aspect of this network was its management support component. The aim of the network is not only to supply with informations about the eutrophication state of the lagoons, but also to provide to local management structures support to their operational management and development. This support takes a variety of forms: studies on specific site on various issues, model application to test management scenario, dissemination of results to various audiences. Over the years, the structure and modus operandi of the network has evolved, especially by increasing the involvement of local coastal lagoon managers. After nearly 10 years of operation, it appears that cooperation between science and management is possible and potentially fruitful for the conservation of coastal lagoons. However, its success is subject to the establishment of a perennial frame such as the Coastal Lagoon Monitoring Network of Languedoc-Roussillon, a major effort in dissemination at different levels and obviously, the whole requires perennial significant financial resources., Le poster présente la démarche qui a conduit à la construction d’un réseau de coopération entre gestionnaires et scientifiques pour la gestion des lagunes côtières de la Région du Languedoc-Roussillon, son architecture et son mode de fonctionnement, les résultats acquis et son évolution au cours du temps. A la fin des années 90, l’eutrophisation et le déficit de connaissances sur le fonctionnement des écosystème furent identifiés comme des problématiques majeures en vue d’une amélioration de la gestion des lagunes côtières sur la façade méditerranéenne française. En 2000, au niveau de la Région du Languedoc-Roussillon, scientifiques (Ifremer) et gestionnaires institutionnels (Conseil régional du Languedoc-Roussillon et Agence de l’Eau Rhône-Méditerranée & Corse, Cépralmar) se sont associés pour construire un réseau (le RSL) afin de pallier à ce besoin. Le cœur de ce réseau est constitué d’un outil opérationnel de diagnostic de l’eutrophisation basé sur une batterie d’indicateurs de l’état de différents compartiments des lagunes côtières (colonne d’eau, phytoplancton, macrophytes, sédiments), outil opéré en routine à pas de temps régulier, mais différent selon les compartiments. Outre l’importante part liée à la communication, l’aspect novateur de ce réseau est sa composante d’aide à la gestion. Le but du réseau n'est pas seulement de donner une indication sur le niveau d'eutrophisation des lagunes, mais également d'apporter aux structures de gestion des étangs côtiers une aide opérationnelle dans la gestion et l'aménagement des sites lagunaires dont elles ont la charge. Cette aide à la gestion revêt plusieurs formes : études spécifiques à un site sur diverses thématiques, application de modèles pour test de scenarii de gestion, diffusion des résultats vers divers publics. Au cours des années, la structure et le mode de fonctionnement du réseau a évolué avec notamment une implication de plus en plus importante des gestionnaires et usagers locaux. Après presque 10 ans de fonctionnement, constat est fait que la coopération entre science et gestion est possible et potentiellement fructueuse pour la préservation des lagunes côtières. Néanmoins, sa réussite est assujettie à la mise en place d’un cadre pérenne comme le Réseau de Suivi Lagunaire, d’un effort conséquent de mise à disposition de l’information à différents niveaux, l’ensemble nécessitant évidemment des moyens financiers importants.

Cette étude est réalisée dans le cadre du projet OBSLAG (OBServatoire des LAGunes) et porte sur les 10 masses d’eau lagunaires méditerranéennes situées à l’aval des cours d’eau suivis depuis 2015 par le « réseau flux » de l'Agence de l’Eau Rhône Méditerranée Corse. Le rapport correspond aux actions réalisées en 2016 dans le cadre du volet « eutrophisation » d’OBSLAG, répondant aux objectifs suivants : (1) réaliser un suivi estival du phytoplancton et de la physico-chimie de l’eau et évaluer l’état DCE de ces compartiments pour la période 2011-2016 sur les 10 masses d’eau lagunaires du suivi « réseau flux », regroupant 13 lagunes poly-euhalines. Ce suivi permet de renforcer la fréquence des suivis DCE sur la colonne d’eau et le phytoplancton, qui ne sont réalisés qu’un été sur deux depuis 2015 ; (2) construire un ou des indicateurs plus sensibles que les indicateurs DCE, mettant en évidence, sur les périodes d’évaluation, les tendances d’évolution et la variabilité de l’état du phytoplancton et de la colonne d’eau, compartiments les plus réactifs des écosystèmes lagunaires. Les suivis réalisés au cours de l’été 2016 sur les 10 masses d’eau lagunaires ont montré que le bon état DCE est atteint pour la période 2011-2016 pour 4 masses d’eau en ce qui concerne le compartiment phytoplancton et pour 7 masses d’eau en ce qui concerne les paramètres physico-chimiques de la colonne d’eau. L’application de méthodes statistiques (bootstrap, tests de Mann Kendall et de Kruskal-Wallis) sur les données de biomasse phytoplanctonique acquises de 2000 à 2016 sur les étangs Palavasiens a permis de montrer l’intérêt du développement d’indicateurs plus sensibles que les indicateurs DCE. La méthode de boostrap proposée est pertinente pour évaluer la confiance accompagnant le diagnostic DCE. Par ailleurs, les tests de Mann Kendall et de Kruskal-Wallis sont efficaces et complémentaires pour détecter précocement des tendances d’évolution et des années particulières au sein des plans de gestion. La détection des changements dans les écosystèmes doit pouvoir se faire à des échelles spatio-temporelles qui sont pertinentes pour les décisions. Du fait de l’inertie des indicateurs DCE et des enjeux vis-à-vis des enjeux de gestion des milieux, il semble nécessaire de maintenir un rythme annuel de suivi et d’évaluation des tendances d’évolution pour la colonne d’eau et le phytoplancton.

Les questions abordées dans le présent rapport concernent la recherche et l’interprétation d’un repère de représentation des données du RSL (colonne d’eau et phytoplancton) pour l’ensemble des stations des lagunes de Provence-Alpes Côte d’Azur (PACA), Languedoc-Roussillon (LR) et Corse : 1) Est-il possible de trouver un repère pertinent de représentation des trajectoires d’évolution pour toutes les stations, en effectuant des regroupement par typologie de stations ? Comment interpréter les deux premiers axes de l’analyse en composantes principales (ACP) ? 2) Le premier axe des repères d’ACP constitue-t-il un « Gradient d’eutrophisation » ? 3) Est-il possible de mettre en évidence un effet météorologique sur les évolutions des teneurs en azote et phosphore inorganiques ? Les repères fournis par les ACP des groupes de lagunes oligo-mésohalines (OMH) et des autres lagunes (LR-PACA-Corse) ont été jugés pertinents pour représenter les évolutions temporelles (« trajectoires ») de l’état vis-à-vis de l’eutrophisation pour chaque station. L’analyse comparée de plusieurs méthodes statistiques a permis : • de confirmer le caractère intégrateur des variables NT, PT et CHLA, qui s’avèrent robustes pour représenter l’état des lagunes vis-à-vis de l’eutrophisation, • de montrer la difficulté à expliquer la variabilité des paramètres dissous, qui indiquent des pollutions ponctuelles ou des apports récents.

Après un rappel des objectifs, du fonctionnement et de la méthode d’interprétation des résultats du réseau de contrôle microbiologique (REMI) et du réseau de surveillance chimique (ROCCH), ce rapport comprend un bilan national et décrit le programme annuel 2020 de la région Occitanie. Il présente l’ensemble des résultats obtenus, en particulier l’estimation de la qualité microbiologique et chimique des zones classées de production de coquillages. En 2020, 24 zones de production ont été suivies par le REMI en Occitanie dont 10 dans l’Aude, 13 dans l’Hérault et 1 dans le Gard au travers de 30 points de suivi. Le taux de réalisation de la surveillance régulière microbiologique en 2020 est de 96,6%, et 46 alertes ont été déclenchées au cours de l’année. La qualité microbiologique estimée en 2021 à partir des résultats de la période 2018-2020 est : « A » pour 2 zones (8,3%), « B » pour 12 zones (50%), « C » pour 6 zones (25%) et « très mauvaise » pour 2 zones (8,3%), le nombre de données est insuffisant pour estimer la qualité de 2 zones de pêche de palourdes pour lesquelles le suivi a été initié en 2020. Parmi ces zones, 16 ont un classement sanitaire concordant avec l’estimation de leur qualité et 6 ont un classement sanitaire plus favorable que l’estimation de leur qualité. La qualité chimique est satisfaisante pour l’ensemble des points suivis.

Dans le cadre du Réseau de Surveillance Prospective, un volet littoral est décliné en 2019, avec l’objectif de proposer un dispositif de recherche des substances d’intérêt émergent (contaminants of emerging concern - CEC) en milieu marin qui permettre in fine d’alimenter la liste des substances pertinentes candidates aux PSEE (Polluants Spécifiques de l’Etat Ecologique). Cela se traduit par l’élaboration en 2019 d’une stratégie d’acquisition de données (substances, matrices, points d’échantillonnage, fréquence et période) et sa déclinaison opérationnelle pour une acquisition de données en 2020-2022. Le principe est d’assurer la pérennité et l’évolutivité de ce dispositif. L’élaboration de cette stratégie s’appuie sur les travaux engagés depuis plus de 10 années par l’Ifremer sur les échantillonneurs passifs en lien avec l’AFB et Aquaref et sur l’expertise et la mise en œuvre de la surveillance environnementale opérées via le ROCCH et le projet de recherche Veille-POP.

L’objectif de cette étude est de caractériser le niveau d’exposition des lagunes aux contaminants chimiques, complétant ainsi notre connaissance de la qualité des masses d’eau côtières méditerranéennes françaises. 23 masses d’eau de transition (soit 26 lagunes) réparties sur 7 départements côtiers en LR et PACA ont été échantillonnées au moyen d’échantillonneurs intégratifs (SBSE, POCIS et DGT) entre mai et août 2010. 141 contaminants issus de différentes familles chimiques (pesticides, médicaments, alkylphenols, HAP, PCB et métaux traces) ont été recherchés et leurs teneurs comparées aux Normes de Qualité Environnementales, lorsque celles-ci existent. La plupart des contaminants disposant d’une NQE ne la dépasse pas, à l’exception du cuivre, des insecticides organochlorés de la famille des cyclodiènes, des lindanes et de l’insecticide endosulfan. 20 masses d’eau de transition sur les 23 suivies sont considérées comme étant en mauvais état chimique à cause de ces polluants et seulement 3 (La Palme, Bagnas et Ponant) en bon état vis-à-vis de la Directive Cadre sur l’Eau (DCE). Sur les 20 masses d’eau en mauvais état, 19 le sont en raison d’un déclassement par au moins un insecticide organochloré.