Accumulation de l’argent et du cuivre chez l’huître japonaise Crassostrea gigas : outils géochimiques pour une optimisation du message environnemental
L’analyse des données de biosurveillance (RNO/ROCCH, IFREMER, 2003-2014) des concentrations en argent (Ag) et cuivre (Cu) dans les huîtres sauvages de 13 sites de la côte atlantique française a montré des variations spatio-temporelles reflétant les pressions locales. De fortes relations entre Ag et Cu semblent en partie dues à des facteurs physiologiques impliqués dans leur bioaccumulation chez les huîtres. Le rapport élémentaire Cu/Ag a montré un potentiel intéressant pour détecter des sources de Ag et Cu, invisibles à travers les concentrations absolues qui sont caractérisées par une très forte variabilité inter-individuelle. Les mesures chimiques et les observations histologiques dans les huîtres sauvages de la Gironde, ont montré une accumulation préférentielle de Ag et Cu dans la glande digestive, accompagnée d’importantes dégradations cellulaires. La méthode innovante du dopage isotopique est très sensible et précise pour observer les cinétiques rapides d’accumulation in vivo de Ag et Cu par voie directe à des niveaux d’exposition réalistes. Les signaux isotopiques ont permis de quantifier l’accumulation rapide des ETM dans les différents organes et d’observer des phénomènes de co-régulation entre Ag et Cu. De plus, elle représente une réelle avancée pour des expérimentations écotoxicologiques permettant d’analyser l’état de contamination initial et après exposition dans le même individu. L’étude de la voie trophique suggère une accumulation de Ag supérieure à celle de Cu chez les algues. La fraction de Ag et Cu particulaire potentiellement biodisponible des particules estuariennes a été estimée à 60% et 82%, respectivement. Les résultats ont montré que cette estimation dépend du temps d’exposition et de la concentration en sédiment, pouvant entraîner d’importantes sous-estimations.
(25/10/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Évaluation des changements hydro-sédimentaires de l'estuaire de la Gironde en lien avec les pressions sur le milieu
La dynamique sédimentaire estuarienne joue un rôle très important pour la qualité de l'eau, les écosystèmes et la navigation. Les estuaires macrotidaux comme la Gironde se caractérisent par la formation de régions très chargées en matière en suspension (MES), appelées zones de turbidité maximale (ZTM), qui influencent le transport et le dépôt des sédiments fins, l'envasement des chenaux, la consommation d'oxygène dissous et le devenir des polluants. L'objectif de ce travail est de comprendre la dynamique hydro-sédimentaire, particulièrement de la ZTM, dans la section fluviale, encore peu étudié, de l'estuaire de la Gironde en lien avec les facteurs de forçage environnementaux et les perturbations du système (changements hydrologiques et morphologiques naturels et anthropiques). La méthodologie de ce travail est basée sur l'analyse de 10 années de données continues de turbidité enregistrées par le réseau de surveillance MAGEST. L'exploitation de telles séries de données, assez novatrice dans les estuaires, a notamment impliqué le développement d'une méthode d'analyse basée sur la combinaison de plusieurs méthodes spectrales. Cette approche est complétée par l'analyse des profils de turbidité et de vitesse de courant lors de cycles de marée, l'analyse de séries temporelles historiques de marée et l'exploitation d'un modèle semi-analytique 2DV. La dynamique sédimentaire de l'estuaire fluvial est d'abord détaillée à toutes les échelles de temps représentatives. A l'échelle de temps intratidale, la distribution verticale des MES et des courants, en deux points d'une même section transversale, a permis de détailler les mécanismes de transport sédimentaire. Les flux particulaires résiduels (totaux, advection, pompage tidal) ainsi estimés pour plusieurs conditions hydrologiques, démontrent le contrôle du pompage tidal sur les flux de MES lors de l'étiage. A l'échelle de temps subtidale, la réponse de la ZTM aux fluctuations hydrologiques (crues, périodes d'augmentation ou diminution continue du débit, variabilité inter-anuelle) est analysée. Ceci a permis de définir plusieurs indicateurs hydrologiques des caractéristiques de la ZTM, qui suggèrent l'intensification de la ZTM au cours des dernières décennies en lien avec la diminution des débit. La contribution relative des facteurs de forçage à la variabilité de la turbidité a été quantifiée pour différentes régions estuariennes et échelles de temps (saisonnière et plurianuelle). L'application de la méthodologique développée à l'estuaire de la Loire, qui dispose de séries de données similaires (réseau SYVEL), a permis de généraliser ces résultats. Enfin, l'effet des changements pluri-décennaux hydrologiques et morphologiques sur la propagation de la marée et la dynamique sédimentaire est détaillé dans la Garonne tidale. Il ressort une amplification du marnage et de la asymétrie de la marée au cours des six dernières décennies, principalement liée aux changements morphologiques naturels dans la Gironde en aval, les extractions de granulat et le changement de régime hydrologique. L'implémentation d'un modèle semi-analytique a permis de vérifier ces résultats et d'analyser leurs implications sur les concentrations de MES et la limite amont de la ZTM.
(21/10/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Toxicity assessment of water-accommodated fractions from two different oils using a zebrafish (Danio rerio) embryo-larval bioassay with a multilevel approach
Petroleum compounds from chronic discharges and oil spills represent an important source of environmental pollution. To better understand the deleterious effects of these compounds, the toxicity of water-accommodated fractions (WAF) from two different oils (brut Arabian Light and Erika heavy fuel oils) were used in this study. Zebrafish embryos (Danio rerio) were exposed during 96 hours at three WAF concentrations (1, 10 and 100% for Arabian Light and 10, 50 and 100% for Erika) in order to cover a wide range of polycyclic aromatic hydrocarbon (PAH) concentrations, representative of the levels found after environmental oil spills. Several endpoints were recorded at different levels of biological organization, including lethal endpoints, morphological abnormalities, photomotor behavioral responses, cardiac activity, DNA damage and exposure level measurements (EROD activity, cyp1a and PAH metabolites). Neither morphological nor behavioral or physiological alterations were observed after exposure to Arabian Light fractions. In contrast, the Erika fractions led a high degree of toxicity in early life stages of zebrafish. Despite of defense mechanisms induced by oil, acute toxic effects have been recorded including mortality, delayed hatching, high rates of developmental abnormalities, disrupted locomotor activity and cardiac failures at the highest PAH concentrations (Σ TPAHs=257029 ± 47231 ng.L-1). Such differences in toxicity are likely related to the oil composition. The use of developing zebrafish is a good tool to identify wide range of detrimental effects and elucidate their underlying foundations. Our work highlights once more, the cardiotoxic action (and potentially neurotoxic) of petroleum-related PAHs.
(Science of the Total Environment. vol. 568, n° 0048-9697, pp. 952–966, 15/10/2016)
LIENSs, INSU - CNRS, ULR, CNRS, BE, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Mass balance of organic contaminants at a large basin scale: case of the Seine River basin (France)
The Seine River basin drains an area of 78 650 km² which accomodates 25% of the French population and 30% of its industry. Thus, it is highly impacted by anthropic activities. As such, the Seine River basin has been the place of numerous studies, mostly achieved within the PIREN-Seine research programme, aiming to quantify several groups of organic micropollutants in different environmental compartments and urban matrices. Among the monitored organic persistent pollutants, Polycyclic Aromatic Hydrocarbons (PAHs), Polybrominated Diphenyl Ethers (PBDEs), Polychlorinated Biphenyls (PCBs), Phthalates (PAEs), Alkylphenols (APs) and perfluoroalkylated substances (PFAs) have been considered. These compounds originate from very contrasting sources in the environment. PAHs are mainly emitted during combustion processes such as household heating and road traffic. PBDEs were mainly used as flamme retardants in plastic and textile industries. Although PCBs are forbidden in France since 1987, they have been extensively used as electric insulators and they can still be found in the environment. Phthalates are still used nowadays as plasticizer. Finally, PFAs can be found in many daily consumers goods as waterproof textiles or non-stick coatings. Along with their diversified sources, differences in their physico-checimal properties strongly impact their environmental fate. This study aims to establish mass balances at the Seine River basin scale for these 6 groups of organic compounds. Mass balances constitute efficient tools for understanding transfer pathways of pollutants in the environment. Databases collected by several research teams working on the Seine River basin were used for the calculations. Along with stocks in soils, most of major environmental fluxes were quantified including atmospheric fallout, erosion from soils, river exports and wastewater treatment plant discharges. A focus on urban mass balances was also carried out considering wastewater, runoff, and sewage discharges at the Paris City scale. First results show very contrasting dynamics depending on organic contaminant groups. PAHs were found to be the most abundant compounds in the soils of the Seine basin. The other contaminant stocks were smaller (PAHs > PAEs > Aps > PCBs > PBDEs > PFAs), likely due to differences in emission sources. In atmospheric fallout, Aps were found to be the most abundant compounds. AP, PAE and PAH atmospheric fallouts were homogeneous across the basin, but highest PBDE and PCB fluxes were measured on Paris City and on agricultural areas respectively. These results suggest that PBDEs present very specific sources and that agricultural soils may act as secondary sources for PCBs. The largest fluxes in the Seine River downstream Paris City were measured for Aps and PAEs and reached about 10 t.yr-1. The lowest fluxes were observed for PBDEs and PCBs (ca. 50 kg.yr-1). Soil erosion seems to be a predominant contributor to PAH and PCB fluxes in the Seine River. For PAEs, wastewater treatment plant discharges appears as a significant contributor. Concerning PBDEs and APs, erosion and urban discharges were approximatively proportionnal to fluxes in the river. However, so far, some sources remain unidentified or poorly quantified and futher treatment of results is required.
(12/10/2016)
LEESU, ENPC, UPEC UP12, METIS, UPMC, EPHE, PSL, CNRS, INERIS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Integration of contamination peaks with variable intensity and duration by the Polar Organic Chemical Integrative Sampler
Contamination level estimate can vary abruptly, depending on season and hydrology of the river at the sampling moment. The Polar Organic Chemical Integrative Sampler (POCIS) may integrate contamination peaks of about 3 days for moderately polar compounds (log Kow = 2-3) [3]. Concerning shorter contamination peaks (less than 1 hour) generated by punctual pollutions or a brutal intake of pesticides in a river (soil leaching, for example), interrogations about its reactivity (e.g. lag time) is still remaining. In this context, a laboratory calibration was made for three different contamination peak patterns, with variable intensity and duration. This experiment was led over a total exposure time of 14 days, and with a selection of 15 pesticides which covering different polarities (log Kow = 0.6-4.7) and classes (herbicides, fungicides, insecticides). Finally, the data showed different accumulation kinetic profiles, with phenomena like burst effect or lag effect, depending on physical-chemical properties of the substances and the exposition duration.
(pp. 1, 04/10/2016)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Occurrence of pharmaceuticals in WWTP effluents and their impact in a karstic rural catchment of Eastern France
(Environmental Science and Pollution Research. vol. 23, n° 0944-1344, pp. 25427-25441, 03/10/2016)
LCE, CNRS, UFC, UBFC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBFC, UFC, UBFC, CNRS, ISA, UCBL, INC-CNRS, CNRS, ISA, UCBL, INC-CNRS, CNRS
Distribution and geochemical behaviour of antimony in the Gironde Estuary A first qualitative approach to regional nuclear accident scenarios
Antimony (Sb) is a highly toxic trace element for which environmental biogeochemical cycles are still relatively poorly known, especially in coastal aquatic systems. In addition, Sb is a fission product in nuclear power plants (NPPs), presenting non-negligible decay and consecutive exposition rates over short to mean terms (i.e., 125Sb isotope half-life of 2.76 years). Understanding the environmental behaviour and fate of natural stable isotopes and combining this with intrinsic properties of the respective radionuclides (e.g. half-life) is essential to predict the environmental fate and potential dispersion of radioisotopes before accidental NPP events. In the present work, the distribution and geochemical behaviour of stable Sb are determined for the first time in the highly turbid Gironde Estuary. Both dissolved and particulate concentrations along the estuarine salinity and turbidity gradients were quantified during low, intermediate and high freshwater discharges. Results clearly suggest that long residence times within the salinity and turbidity gradients favour the observed non-conservative, additive behaviour of Sb. Distribution coefficients (log10 Kd ≈ 3.5–4.4 l kg− 1) indicate that in the Maximum Turbidity Zone (MTZ; SPM ~ 1000 mg l− 1) ~ 90% of total Sb occurs in the particulate phase, compared to only ~ 10% in the less turbid portions of the estuary (SPM ≤ 100 mg l− 1). We propose a first/broad qualitative approximation (scenarios) to possible behaviour and dispersion of Sb radionuclides in case of accidental release from the Blayais NPP located on the Gironde Estuary. Our results suggest that the hydrological situation and the position of the MTZ during a potential accident can be primordial to residence time and distribution pathways in the estuary. We estimate that (i) high river discharge and a downstream position of the MTZ may favour Sb radionuclide adsorption onto particles, implying long (months to years) residence times in the estuary and a high risk of seasonal upstream transport into the city of Bordeaux, whereas (ii) under low discharge conditions, dissolved Sb species will predominate implying rapid transport and higher dispersion along the coast. © 2016 Elsevier B.V.
(Marine Chemistry. vol. 185, n° 0304-4203, pp. 65-73, 01/10/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSN/PRP-ENV/SERIS/LRTE, IRSN
Inputs and seasonal removal of pharmaceuticals in the estuarine Garonne River
Pharmaceuticals were screened in the estuarine Garonne River to investigate the role of estuaries as passive or active transfer compartments in the removal of these compounds. Monthly monitoring of 53 pharmaceuticals from various therapeutic classes at 6 sampling points over 18 months showed that most compounds were frequently detected with median concentrations in the low ng L− 1 range. Saline intrusion was responsible of an overall dilution but an enrichment from the treated urban effluents of Bordeaux city was also observed with increases resulting from this input being compound dependent. An average cumulated load of 10 kg of the monitored pharmaceuticals was found to enter the estuary daily from the catchment area. After normalization to the persistent marker carbamazepine, a large majority of the compounds were found to exhibit in-stream attenuation during summer while this removal was enhanced farther down the estuary, indicating a likely effect of residence time, temperature and suspended solid concentration on the stability of the pharmaceuticals.
(Marine Chemistry. vol. 185, n° 0304-4203, pp. 3-11, 01/10/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The impact of long-term hydrocarbon exposure on the structure, activity, and biogeochemical functioning of microbial mats
Photosynthetic microbial mats are metabolically structured systems driven by solar light. They are ubiquitous and can grow in hydrocarbon-polluted sites. Our aim is to determine the impact of chronic hydrocarbon contamination on the structure, activity, and functioning of a microbial mat. We compared it to an uncontaminated mat harboring similar geochemical characteristics. The mats were sampled in spring and fall for 2 years. Seasonal variations were observed for the reference mat: sulfur cycle-related bacteria dominated spring samples, while Cyanobacteria dominated in autumn. The contaminated mat showed minor seasonal variation; a progressive increase of Cyanobacteria was noticed, indicating a perturbation of the classical seasonal behavior. Hydrocarbon content was the main factor explaining the differences in the microbial community structure; however, hydrocarbonoclastic bacteria were among rare or transient Operational Taxonomic Units (OTUs) in the contaminated mat. We suggest that in long-term contaminated systems, hydrocarbonoclastic bacteria cannot be considered a sentinel of contamination
(Marine Pollution Bulletin. vol. 111, n° 0025-326X, pp. 115-125, 01/10/2016)
LANL, Ecosym, UM1, UM2, IFREMER, CNRS, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LGC, INRA, ENVT, Toulouse INP, Comue de Toulouse, LMAP, UPPA, CNRS, UBIA, INRA, IPREM, UPPA, INC-CNRS, CNRS
Development and validation of a video analysis software for marine benthic applications
Our aim in the EU funded JERICO project was to develop a flexible and scalable imaging platform that could be used in the widest possible set of ecological situations. Depending on research objectives, both image acquisition and analysis procedures may indeed differ. Up to now the attempts for automating image analysis procedures have consisted of the development of pieces of software specifically designed for a given objective. This led to the conception of a new software: AVIExplore. Its general architecture and its three constitutive modules: AVIExplore — Mobile, AVIExplore — Fixed and AVIExplore — ScriptEdit are presented. AVIExplore provides a unique environment for video analysis. Its main features include: (1) image selection tools allowing for the division of videos in homogeneous sections, (2) automatic extraction of targeted information, (3) solutions for long-term time-series as well as large spatial scale image acquisition, (4) real time acquisition and in some cases real time analysis, and (5) a large range of customized image-analysis possibilities through a script editor. The flexibility of use of AVIExplore is illustrated and validated by three case studies: (1) coral identification and mapping, (2) identification and quantification of different types of behaviors in a mud shrimp, and (3) quantification of filtering activity in a passive suspension-feeder. The accuracy of the software is measured comparing with visual assessment. It is: 90.2%, 82.7%, and 98.3% for the three case studies, respectively. Some of the advantages and current limitations of the software as well as some of its foreseen advancements are then briefly discussed.
(Journal of Marine Systems. vol. 162, n° 0924-7963, pp. 4-17, 01/10/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS