Traitement de la micropollution organostannique aqueuse et sédimentaire par des procédés d’oxydation avancée. TBT-STOP (TBT-Samples Treated by Oxydation Processes)

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Tributyltin in Wastewater: Influence on the Performance of Suspended Growth Biological Processes

International audienceThe aim of this study was to evaluate the potential effect of tributyltin (TBT) on the performance of suspended-growth biological processes. The influence of TBT was evaluated for (i) the endogenous and exogenous respirations of heterotrophic micro-organisms in laboratory-scale batch reactors, taken from a municipal wastewater treatment plant and (ii) chemical oxygen demand (COD) removal, sludge production and oxygen consumption of a pilot-sale membrane bioreactor (MBR) system inoculated with heterotrophic micro-organisms taken from a MBR system. The batch experiments showed that the presence of TBT was likely to modify the activity of bacterial populations in endogenous conditions. The increase in endogenous oxygen needs suggested an increase in the maintenance requirements, essentially to manage the chemical stress induced by the presence of TBT. If the addition of TBT did not perturb COD removal in an MBR system, it limited sludge production and increased oxygen requirements; it is assumed that these modifications were linked with the necessity for the biomass to adapt in this stressful environment, as reflected by an increase in the maintenance requirements. These results emphasised that the respiratory activity of the bacterial cultures was modified by the presence of TBT, in the sense that an excess of oxygen was required to adapt to this chemical stress.Le but de cette étude était d'évaluer l'effet potentiel du tributylétain (TBT) sur la performance des processus biologiques à croissance suspendue. L'influence du TBT a été évaluée pour (i) les respirations endogène et exogène de micro-organismes hétérotrophes dans des réacteurs batch à l'échelle du laboratoire, provenant d'une station d'épuration municipale et (ii) l'élimination de la demande chimique en oxygène (DCO), la production de boues et la consommation d'oxygène d'un système pilote de bioréacteur à membrane (MBR) inoculé avec des micro-organismes hétérotrophes provenant d'un système MBR. Les expériences en batch ont montré que la présence de TBT était susceptible de modifier l'activité des populations bactériennes en conditions endogènes. L'augmentation des besoins endogènes en oxygène a suggéré une augmentation des besoins de maintenance, essentiellement pour gérer le stress chimique induit par la présence de TBT. Si l'ajout de TBT n'a pas perturbé l'élimination de la DCO dans un système MBR, il a limité la production de boues et augmenté les besoins en oxygène ; on suppose que ces modifications sont liées à la nécessité pour la biomasse de s'adapter dans cet environnement stressant, comme le reflète l'augmentation des besoins de maintenance. Ces résultats ont souligné que l'activité respiratoire des cultures bactériennes était modifiée par la présence de TBT, dans le sens où un excès d'oxygène était nécessaire pour s'adapter à ce stress chimique

Behaviour of butyltin compounds in the sediment pore waters of a contaminated marina (Port Camargue, South of France)

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Design et calibration de chemcatcher pour la surveillance de butylétains dans les zones portuaires

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Deciphering As and Cu cycling in sediment pore waters in a large marina (Port Camargue, southern France) using a multi-tracer (Fe, Mn, U, Mo) approach

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Cu isotope records of Cu-based antifouling paints in sediment core profiles from the largest European Marina, The Port Camargue

The intensive use of copper (Cu) compounds as an alternative biocide in antifouling paints (APs) has resulted in wide Cu contamination into the marine environment, especially near marina harbor activities. In this work, the applicability of Cu isotopes to discriminate Cu origins related to the use of Cu-based APs in marine environments was tested. To this, Cu isotopes in APs, shipyard sludges, and sediment cores sampled in the Cu-contaminated Mediterranean marina of Port Camargue were determined. APs represent an important dominant anthropogenic source for metals in this site, making it ideal to test Cu isotopes as tracers. The overall isotope composition of four sediment cores and a surface sample varied between −0.13 and 0.44 ‰ (δ65Cu relative to NIST-976). Selected APs brands show a similar Cu concentration ~0.15 % and δ65Cu average of 0.54 ± 0.05 ‰. The plot of δ65Cu vs concentration for all datasets allowed dissociating natural and APs end-members. However, sample isotope systematics were not consistent with a conservative mixing binary source process. Heavily Cu-contaminated sediments show isotope signatures lighter than APs brands. However, the most Cu-contaminated sample, located directly above the careening area, shows a δ65Cu slightly lighter than APs (0.44 ‰ vs 0.54 ‰, respectively). Results suggest the preferential releasing of a heavy isotope pool by APs when these compounds are solubilized in seawater. The isotope fractionation was attributed to potential chemical Cu coordination changes during its elemental partition between paint and marina seawater and the fractionation induced by the organic ligands in the water column, before deposition. Further laboratory experiments are recommended to model the isotope fractionation mechanisms related to Cu release by APs. Because the APs' isotope signature is modified in marine environments, the use of Cu isotopes as tracers of AP in marine environments is challenging and needs more investigation

Trace elements in the sediments of a large Mediterranean marina (Port Camargue, France): Levels and contamination history

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Study of passive sampler calibration (Chemcatcher®) for environmental monitoring of organotin compounds: Matrix effect, concentration levels and laboratory vs in situ calibration

International audienceApplication of Chemcatcher® to monitor organotin compounds [monobutyltin (MBT), dibutyltin (DBT) and tributlytin (TBT)] in sea water has been little developed. Prior to the measurement of the time-weighted average water concentrations (TWAC), a calibration step is required to determine sampling rates (Rs) which is usually assessed in a flow-through laboratory pilot where experimental conditions are well controlled. This paper investigates the effect of the water matrix (tap water vs real sea water from the harbor of Port Camargue in France) and organotin concentrations on the uptake rates of organotin compounds. Laboratory calibrations provided sampling rates in the range of 66–225 mL.day−1 in high concentration (usually used for laboratory calibrations) and in the range of 30–56 mL.day−1 at low concentrations (environmental range). When the tank is filled with real sea water, sampling rates were found to be in the range of 38–177 mL.day−1. In order to demonstrate the efficiency of Chemcatcher® in real conditions, in situ calibration was done in the harbor of Port Camargue. This calibration has been done in order to replicate environmental conditions: compounds concentrations, hydrodynamic and water matrix effects. To compare the impact of calibration procedures on TWAC determination, Chemcatcher® was deployed in the harbor of Port Camargue and spot sampling was performed to monitor the concentrations of organotins in water throughout the exposure period. Results obtained using the field Rs determined by in situ calibration were more reliable. In this case, TWAC is in agreement with spot sampling concentration

The environmental legacy of historic Pb-Zn-Ag-Au mining in river basins of the southern edge of the Massif Central (France)

International audienceThe main rivers (Aude, Orb, Herault) that discharge into the Gulf of Lions and the west bank tributaries of the Rhone River including the Gardon have former non-ferrous metal mines in their upper drainage basin. Using unpublished data and data from the literature, this study provides an integrated overview of the contamination of water and sediment along the continent-sea continuum and of its impacts on the biota and on human health. In the upper part of these basins, water and stream sediments are enriched in metal(-loids) compared to median European concentrations. Arsenic is the main contaminant in the rivers Aude and Gardon d'Anduze, Sb in the Orb and Gardon d'Alès, and Tl in the Herault river. A rapid reduction in dissolved and particulate concentrations was systematically observed along the river due to dilution and precipitation. The high concentrations of metal(-loid)s observed suggest that the former mining activity still represents a potential threat for the environment, but the lack of high temporal resolution monitoring, especially during Mediterranean floods, prevents accurate assessment of metal fluxes from these rivers to the Mediterranean Sea. Studies dedicated to the impacts on human health are too rare, given that studies have shown a higher rate of arsenic-specific cancer near Salsigne mine in the Aude River basin and cases of saturnism in children in the upper Herault River basin. These studies underline the need to take environmental health issues into consideration not only in these watersheds but around the entire Mediterranean basin, which harbors numerous metalliferous ores that have been mined for millennia

Spéciation de l’arsenic et potentiel génétique bactérien dans deux lacs de carrière alcalins de la région minière de Zeida (Maroc)

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