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
Past and present platinum contamination of a major European fluvial–estuarine system: Insights from river sediments and estuarine oysters
(Marine Chemistry. vol. 185, n° 0304-4203, pp. 104-110, 01/10/2016)
EPOC, EPHE, PSL, UB, INSU - 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
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
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
Experimental Study of the Formation of Organosulfates from α-Pinene Oxidation. Part I: Product Identification, Formation Mechanisms and Effect of Relative Humidity
(Journal of Physical Chemistry A. vol. 120, n° 1089-5639, pp. 7909-7923, 30/09/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
How to Assess Temporal Changes of Point and Diffuse Contamination in a Rural Karstic Watershed? Relevance of Suspended Particulate Matter (SPM) for Efficient Monitoring
(Water, Air, and Soil Pollution. vol. 227, n° 0049-6979, pp. 384, 27/09/2016)
LCE, CNRS, UMLP, UBFC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBFC, UMLP, UBFC, CNRS
Chemical Forms of Mercury in Human Hair Reveal Sources of Exposure
Humans are contaminated by mercury in different forms from different sources. In practice, contamination by methylmercury from fish consumption is assessed by measuring hair mercury concentration, whereas exposure to elemental and inorganic mercury from other sources is tested by analysis of blood or urine. Here, we show that diverse sources of hair mercury at concentrations as low as 0.5 ppm can be individually identified by specific coordination to C, N, and S ligands with high energy-resolution X-ray absorption spectroscopy. Methylmercury from seafood, ethylmercury used as a bactericide, inorganic mercury from dental amalgams, and exogenously derived atmospheric mercury bind in distinctive intermolecular configurations to hair proteins, as supported by molecular modeling. A mercury spike located by X-ray nanofluorescence on one hair strand could even be dated to removal of a single dental amalgam. Chemical forms of other known or putative toxic metals in human tissues could be identified by this approach with potential broader applications to forensic, energy, and materials science.
(Environmental Science and Technology. vol. 50, n° 0013-936X, pp. 10721-10729, 23/09/2016)
ISTerre, IFSTTAR, INSU - CNRS, USMB [Université de Savoie] [Université de Chambéry], CNRS, UGA [2016-2019], LCE, CNRS, UMLP, UBFC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ESRF, IECB, UB, INSERM, CNRS
Why is Asari (= Manila) clam Ruditapes philippinarum fitness poor in Arcachon Bay: a meta-analysis to answer?
Asari (= Manila) clam, Ruditapes philippinarum, is the second bivalve mollusc in terms of production in the world and, in many coastal areas, can beget important socio-economic issues. In Europe, this species was introduced after 1973. In Arcachon Bay, after a decade of aquaculture attempt, Asari clam rapidly constituted neo-naturalized population which is now fished. However, recent studies emphasized the decline of population and individual performances. In the framework of a national project (REPAMEP), some elements of fitness, stressors and responses in Arcachon bay were measured and compared to international data (41 publications, 9 countries). The condition index (CI=flesh weight/shell weight) was the lowest among all compared sites. Variation in average Chla concentration explained 30% of variation of CI among different areas. Among potential diseases, perkinsosis was particularly prevalent in Arcachon Bay, with high abundance, and Asari clams underwent Brown Muscle Disease, a pathology strictly restricted to this lagoon. Overall element contamination was relatively low, although arsenic, cobalt, nickel and chromium displayed higher values than in other ecosystems where Asari clam is exploited. Finally, total hemocyte count (THC) of Asari clam in Arcachon Bay, related to the immune system activity, exhibited values that were also under what is generally observed elsewhere. In conclusion, this study, with all reserves due to heterogeneity of available data, suggest that the particularly low fitness of Asari clam in Arcachon Bay is due to poor trophic condition, high prevalence and intensity of a disease (perkinsosis), moderate inorganic contamination, and poor efficiency of the immune system.
(Estuarine, Coastal and Shelf Science. vol. 179, n° 0272-7714, pp. 226-235, 20/09/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, PHYC, DYNECO, IFREMER, LERAR, COAST, IFREMER, LRHA, HGS, IFREMER
Assessing and managing the risks of hypoxia in transitional waters: a case study in the tidal Garonne River (South-West France)
The Gironde estuary (S-W France) is one of the largest European macrotidal estuaries. In the tidal Garonne River, its main tributary, episodes of low (<5 mg L−1) to hypoxic (<2 mg L−1) dissolved oxygen (DO) concentrations have been occasionally recorded close to Bordeaux, about 100 km from the mouth. Projected long-term environmental changes (increase in temperature and population, decrease in river discharge) suggest the establishment of summer chronic oxygen deficiency in the tidal Garonne River in the next decades. Assessing and managing the risk of hypoxia on such a large, hyper-turbid fluvio-estuarine system is complex, due to the different forcing factors (temperature, river discharge, turbidity, urban wastes) acting over a wide range of temporal and spatial scales. In this context, we show the interest of a real-time, high-frequency monitoring of the water quality, the MAGEST network, which continuously records since 2005 temperature, salinity, turbidity, and dissolved oxygen in surface waters in Bordeaux. Through the analysis of the 10-year DO records, we demonstrate the interest of a high-frequency, long-term database to better document DO variability and to define the controlling factors of DO concentrations. This real-time monitoring is also of great interest for the development of manager’s oriented tools and the follow-up of DO objectives in the tidal Garonne River.
(Environmental Science and Pollution Research. vol. 24, n° 0944-1344, pp. 3251-3259, 14/09/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS