85 research outputs found
Roles of regional hydrodynamic and trophic contamination in cadmium bioaccumulation by Pacific oysters in the Marennes-Oléron Bay (France)
International audienceThe Marennes-OlĂ©ron Bay, hosting the largest oyster production in France, is influenced by the historic polymetallic pollution of the Gironde Estuary. Despite management efforts and decreasing emissions in the Gironde watershed, cadmium levels in oysters from the bay are close to the consumption limit (5 lg g Ă1 dw, EC). From mid April to mid July 2009, we investigated the role of tidal resuspension and regional hydrodynamics on Cd speciation (seawater, SPM, phytoplankton, sediment, microphytobenthos) and bioaccumulation in 18 month-old oysters (gills, digestive glands, rests of tissues) reared under natural conditions (i) at $60 cm above the sediment and (ii) on the sediment surface. Dissolved and particulate Cd concentrations in surface and bottom waters were similar and constant over tidal cycle suggesting the absence of Cd release during sediment resuspension. Temporal dissolved and particulate Cd concentrations were closely related to Gironde Estuary water discharges, showing increasing concentrations during flood situations and decreasing concentrations afterwards. Cd depletion in the water column was associated with increasing Cd in the [20-100 lm] plankton fraction, suggesting Cd bioaccumulation. After 3 months, enrichment factors of Cd in tissues of oysters exposed in the water column and directly on the sediment were respectively 3.0 and 2.2 in gills, 4.7 and 3.2 in digestive glands and 4.9 and 3.4 in remaining tissues. Increasing Cd bioaccumulation in gills, digestive glands and remaining tissues can be related to elevated dissolved Cd in the bay, suggesting gill contamination via the direct pathway and subsequent internal redistribution of Cd to other organs and tissues. Elevated Cd contents in oysters reared on tables could be attributed to different trophic Cd transfer (phytoplankton versus micro-phytobenthos) or to different oyster metabolisms between the rearing conditions as suggested by metal-lothionein concentrations
A Methodology to Characterize Riverine Macroplastic Emission Into the Ocean
Land-based macroplastic is considered one of the major sources of marine plastic debris. However, estimations of plastic emission from rivers into the oceans remain scarce and uncertain, mainly due to a severe lack of standardized observations. To properly assess global plastic fluxes, detailed information on spatiotemporal variation in river plastic quantities and composition are urgently needed. In this paper, we present a new methodology to characterize riverine macroplastic dynamics. The proposed methodology was applied to estimate the plastic emission from the Saigon River, Vietnam. During a 2-week period, hourly cross-sectional profiles of plastic transport were made across the river width. Simultaneously, sub-hourly samples were taken to determine the weight, size and composition of riverine macroplastics (>5 cm). Finally, extrapolation of the observations based on available hydrological data yielded new estimates of daily, monthly and annual macroplastic emission into the ocean. Our results suggest that plastic emissions from the Saigon River are up to four times higher than previously estimated. Importantly, our flexible methodology can be adapted to local hydrological circumstances and data availability, thus enabling a consistent characterization of macroplastic dynamics in rivers worldwide. Such data will provide crucial knowledge for the optimization of future mediation and recycling efforts
Description of the post-consumer plastic packaging value chains in a commune of a rural district of HCMC: implications for EPR implementation. Technical report under the project âRethinking Plastics â Circular Economy Solutions to Marine Litter âfunded by the European Union and the German Federal Ministry for Economic Cooperation and Development (BMZ), 31 p.
Description of the post-consumer plastic packaging value chains in a commune of a rural district of HCMC: implications for EPR implementation. Technical report under the project âRethinking Plastics â Circular Economy Solutions to Marine Litter âfunded by the European Union and the German Federal Ministry for Economic Cooperation and Development (BMZ), 31 p.
Mécanismes biogéochimiques de la contamination des hußtres Crassostrea gigas en Cadmium en baie de Marennes Oléron
La baie de Marennes OlĂ©ron, premier site ostrĂ©icole français, est influencĂ©e par la pollution polymĂ©tallique historique de lâestuaire de la Gironde avec des concentrations en cadmium dans les huĂźtres proches de la limite de consommation europĂ©enne (RNO 2006; 5 ÎŒg.g-1 ps, ECNo.466/2001). Ces travaux de recherche pluridisciplinaires ont pour objectif de caractĂ©riser le comportement des ETM en zone cĂŽtiĂšre et les mĂ©canismes de contamination en ETM des huĂźtres, spĂ©cifiquement en Cd, dans la baie de Marennes OlĂ©ron. Pour cela, sept missions ocĂ©anographiques en pĂ©riode contrastĂ©e ont permis de caractĂ©riser la spĂ©ciation des ETM Ă lâembouchure des estuaires de la Charente et de la Gironde ainsi quâau Pertuis de Maumusson.Une Ă©tude spatio-temporelle complĂ©mentaire des sĂ©diments de surface de la baie de Marennes OlĂ©ron a montrĂ© un enrichissement des sĂ©diments de surface en Cd dans la zone sud baie,confirmant la connexion des eaux girondines et lâapport en Cd particulaire Ă la baie par le Pertuis de Maumusson. Cette zone sud a ainsi Ă©tĂ© choisie pour mener une transplantation dâhuĂźtres pendant trois mois. Lâhydrodynamique rĂ©gionale, observĂ©e par imagerie satellite, a prĂ©sentĂ© unrĂŽle important dans la distribution et la variation temporelle des concentrations en Cd dissous et particulaires minĂ©rales de la baie. La bioaccumulation en Cd des diffĂ©rents organes dâhuĂźtres cultivĂ©es sur table a Ă©tĂ© plus importante que celle des huĂźtres cultivĂ©es directement sur le sol,suggĂ©rant le faible rĂŽle de la diffusion de Cd par la remise en suspension des sĂ©diments de surface et du microphytobenthos sur la bioaccumulation. De plus, le temps dâimmersion Ă©tant relativement proche entre les deux conditions, nous suggĂ©rons que la voie trophique via le plankton pĂ©lagique participe Ă la contamination des huĂźtres en plus de la voie directe. Cette contribution de la voie trophique a Ă©tĂ© confirmĂ©e lors dâexpĂ©rimentations en conditions contrĂŽlĂ©es en laboratoire par le dĂ©veloppement dâune mĂ©thode de traçage simultanĂ© des voies de contamination directe et trophique par ajouts dâisotopes stables de Cd, conduites pour des concentrations 10 fois supĂ©rieures Ă lâenvironnement et des concentrations rĂ©alistes observĂ©es en baie de Marennes OlĂ©ron (40 ng.l-1 et ~0.7 mg.kg-1).The Marennes-OlĂ©ron Bay, hosting the largest oyster production in France, is influenced by thehistoric polymetallic pollution of the Gironde Estuary, with cadmium levels in oysters close tothe consumption limit level (5 ÎŒg.g-1 dw, EC No.466/2001). The aim of this pluridisciplinarywork was to characterize the behaviour of trace metals in the coastal zone and the mechanisms ofCd contamination in oysters in the Marennes OlĂ©ron Bay. Seven oceanographic cruises wereconducted during contrasting season to characterize trace metals behaviour and speciation in theGironde and Charente estuaries and the coastal zone. Then, a spatial and temporal study of tracemetals in the surface sediments of the Marennes-OlĂ©ron Bay showed punctual Cd-enrichedsediments in the southern part, reflecting the connexion with the Gironde waters and theparticulate Cd inputs via the Maumusson inlet. Thus, this area was chosen to study Cdbioaccumulation in oysters over a three months transplantation. The regional hydrodynamic,observed by satellite images, played an important role on Cd speciation and the temporalvariability of dissolved and particulate Cd concentrations. Cadmium bioaccumulation in organsof oysters reared on tables at 60 cm height was more important than in oysters reared near thesediment, suggesting the absence of Cd released during tidal suspension from sediment andmicrophytobenthos. Furthermore, as the immersion time was closed between the two rearingconditions, we suggested Cd bioaccumulation via the direct pathway and also via trophicpathway of contamination by pelagic plankton ingestion. This trophic pathway of Cdcontamination was validated during laboratory experiments using a simultaneous tracing of Cddirect and trophic pathways in oysters by stable isotope spikes at concencentrations 10-foldhigher than the Gironde Estuary and at realistic concentrations observed in the Marennes-OlĂ©ronBay
Description of the post-consumer plastic packaging value chains in a commune of a rural district of HCMC: implications for EPR implementation. Technical report under the project âRethinking Plastics â Circular Economy Solutions to Marine Litter âfunded by the European Union and the German Federal Ministry for Economic Cooperation and Development (BMZ), 31 p.
Mécanismes biogéochimiques de la contamination des hußtres Crassostrea gigas en Cadmium en baie de Marennes Oléron
La baie de Marennes OlĂ©ron, premier site ostrĂ©icole français, est influencĂ©e par la pollution polymĂ©tallique historique de lâestuaire de la Gironde avec des concentrations en cadmium dans les huĂźtres proches de la limite de consommation europĂ©enne (RNO 2006; 5 ÎŒg.g-1 ps, ECNo.466/2001). Ces travaux de recherche pluridisciplinaires ont pour objectif de caractĂ©riser le comportement des ETM en zone cĂŽtiĂšre et les mĂ©canismes de contamination en ETM des huĂźtres, spĂ©cifiquement en Cd, dans la baie de Marennes OlĂ©ron. Pour cela, sept missions ocĂ©anographiques en pĂ©riode contrastĂ©e ont permis de caractĂ©riser la spĂ©ciation des ETM Ă lâembouchure des estuaires de la Charente et de la Gironde ainsi quâau Pertuis de Maumusson.Une Ă©tude spatio-temporelle complĂ©mentaire des sĂ©diments de surface de la baie de Marennes OlĂ©ron a montrĂ© un enrichissement des sĂ©diments de surface en Cd dans la zone sud baie,confirmant la connexion des eaux girondines et lâapport en Cd particulaire Ă la baie par le Pertuis de Maumusson. Cette zone sud a ainsi Ă©tĂ© choisie pour mener une transplantation dâhuĂźtres pendant trois mois. Lâhydrodynamique rĂ©gionale, observĂ©e par imagerie satellite, a prĂ©sentĂ© unrĂŽle important dans la distribution et la variation temporelle des concentrations en Cd dissous et particulaires minĂ©rales de la baie. La bioaccumulation en Cd des diffĂ©rents organes dâhuĂźtres cultivĂ©es sur table a Ă©tĂ© plus importante que celle des huĂźtres cultivĂ©es directement sur le sol,suggĂ©rant le faible rĂŽle de la diffusion de Cd par la remise en suspension des sĂ©diments de surface et du microphytobenthos sur la bioaccumulation. De plus, le temps dâimmersion Ă©tant relativement proche entre les deux conditions, nous suggĂ©rons que la voie trophique via le plankton pĂ©lagique participe Ă la contamination des huĂźtres en plus de la voie directe. Cette contribution de la voie trophique a Ă©tĂ© confirmĂ©e lors dâexpĂ©rimentations en conditions contrĂŽlĂ©es en laboratoire par le dĂ©veloppement dâune mĂ©thode de traçage simultanĂ© des voies de contamination directe et trophique par ajouts dâisotopes stables de Cd, conduites pour des concentrations 10 fois supĂ©rieures Ă lâenvironnement et des concentrations rĂ©alistes observĂ©es en baie de Marennes OlĂ©ron (40 ng.l-1 et ~0.7 mg.kg-1).The Marennes-OlĂ©ron Bay, hosting the largest oyster production in France, is influenced by thehistoric polymetallic pollution of the Gironde Estuary, with cadmium levels in oysters close tothe consumption limit level (5 ÎŒg.g-1 dw, EC No.466/2001). The aim of this pluridisciplinarywork was to characterize the behaviour of trace metals in the coastal zone and the mechanisms ofCd contamination in oysters in the Marennes OlĂ©ron Bay. Seven oceanographic cruises wereconducted during contrasting season to characterize trace metals behaviour and speciation in theGironde and Charente estuaries and the coastal zone. Then, a spatial and temporal study of tracemetals in the surface sediments of the Marennes-OlĂ©ron Bay showed punctual Cd-enrichedsediments in the southern part, reflecting the connexion with the Gironde waters and theparticulate Cd inputs via the Maumusson inlet. Thus, this area was chosen to study Cdbioaccumulation in oysters over a three months transplantation. The regional hydrodynamic,observed by satellite images, played an important role on Cd speciation and the temporalvariability of dissolved and particulate Cd concentrations. Cadmium bioaccumulation in organsof oysters reared on tables at 60 cm height was more important than in oysters reared near thesediment, suggesting the absence of Cd released during tidal suspension from sediment andmicrophytobenthos. Furthermore, as the immersion time was closed between the two rearingconditions, we suggested Cd bioaccumulation via the direct pathway and also via trophicpathway of contamination by pelagic plankton ingestion. This trophic pathway of Cdcontamination was validated during laboratory experiments using a simultaneous tracing of Cddirect and trophic pathways in oysters by stable isotope spikes at concencentrations 10-foldhigher than the Gironde Estuary and at realistic concentrations observed in the Marennes-OlĂ©ronBay
Des contaminations record de plastiques en eau douce
Si la pollution par les plastiques des océans est fortement médiatisée, celle dans les eaux douces l'est moins. Or, il pouvait s'agir d'un problÚme sanitaire et environnemental majeur
Regard sur les vies sociales et environnementales des matiĂšres plastiques au Vietnam
International audienc
Regard sur les vies sociales et environnementales des matiĂšres plastiques au Vietnam
International audienc
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