Seasonal variations and annual fluxes of arsenic in the Garonne, Dordogne and Isle Rivers, France

Masson, Matthieu; Schäfer, Jörg; Blanc, Guillaume; Anschutz, Pierre

doi:10.1016/j.scitotenv.2006.10.039

Cited by 68 publications

(33 citation statements)

References 43 publications

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“…The Garonne and the Dordogne respectively contribute 65% and 35% of freshwater inputs in the Gironde estuary. The freshwater discharge in the Garonne ranges from less than 100 m in the Dordogne [28]. The Gironde's morphology is typical of wave and tide dominated estuaries.…”

Section: Gironde Estuarymentioning

confidence: 99%

Toward Sentinel-2 High Resolution Remote Sensing of Suspended Particulate Matter in Very Turbid Waters: SPOT4 (Take5) Experiment in the Loire and Gironde Estuaries

et al. 2015

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At the end of the SPOT4 mission, a four-month experiment was conducted in 2013 to acquire high spatial (20 m) and high temporal (5 days) resolution satellite data. In addition to the SPOT4 (Take5) dataset, we used several Landsat5, 7, 8 images to document the variations in suspended particulate matter (SPM) concentration in the turbid Gironde and Loire estuaries (France). Satellite-derived SPM concentration was validated using automated in situ turbidity measurements from two monitoring networks. The combination of a multi-temporal atmospheric correction method with a near-infrared to visible ), at an accuracy sufficient to detect the maximum turbidity zone (MTZ) in both estuaries. Such a multi-sensor approach can be applied to high spatial resolution satellite archives and to the new ESA Sentinel-2 mission. It offers a promising framework to study the response of estuarine ecosystems to global changes at unprecedented spatio-temporal resolution.

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Section: Gironde Estuarymentioning

confidence: 99%

Toward Sentinel-2 High Resolution Remote Sensing of Suspended Particulate Matter in Very Turbid Waters: SPOT4 (Take5) Experiment in the Loire and Gironde Estuaries

et al. 2015

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“…These rivers' watersheds represent 57,000 km 2 and 24,000 km 2 , and they supply respectively 65% and 35% freshwater inputs into the Estuary. The Garonne's freshwater discharge ranges from less than 100 m 3 ·s −1 to more than 4000 m 3 ·s −1 , while the Dordogne discharge fluctuates between 200 and 1500 m 3 ·s −1 [38]. The Gironde's flow rate averages 1100 m 3 ·s −1 and its morphology is typical of a macro-tidal estuary (tidal ranges from 2 to 5 m) impacted by waves.…”

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confidence: 99%

Atmospheric Corrections and Multi-Conditional Algorithm for Multi-Sensor Remote Sensing of Suspended Particulate Matter in Low-to-High Turbidity Levels Coastal Waters

et al. 2017

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Abstract:The accurate measurement of suspended particulate matter (SPM) concentrations in coastal waters is of crucial importance for ecosystem studies, sediment transport monitoring, and assessment of anthropogenic impacts in the coastal ocean. Ocean color remote sensing is an efficient tool to monitor SPM spatio-temporal variability in coastal waters. However, near-shore satellite images are complex to correct for atmospheric effects due to the proximity of land and to the high level of reflectance caused by high SPM concentrations in the visible and near-infrared spectral regions. The water reflectance signal (ρ w ) tends to saturate at short visible wavelengths when the SPM concentration increases. Using a comprehensive dataset of high-resolution satellite imagery and in situ SPM and water reflectance data, this study presents (i) an assessment of existing atmospheric correction (AC) algorithms developed for turbid coastal waters; and (ii) a switching method that automatically selects the most sensitive SPM vs. ρ w relationship, to avoid saturation effects when computing the SPM concentration. The approach is applied to satellite data acquired by three medium-high spatial resolution sensors (Landsat-8/Operational Land Imager, National Polar-Orbiting Partnership/Visible Infrared Imaging Radiometer Suite and Aqua/Moderate Resolution Imaging Spectrometer) to map the SPM concentration in some of the most turbid areas of the European coastal ocean, namely the Gironde and Loire estuaries as well as Bourgneuf Bay on the French Atlantic coast. For all three sensors, AC methods based on the use of short-wave infrared (SWIR) spectral bands were tested, and the consistency of the retrieved water reflectance was examined along transects from low-to high-turbidity waters. For OLI data, we also compared a SWIR-based AC (ACOLITE) with a method based on multi-temporal analyses of atmospheric constituents (MACCS). For the selected scenes, the ACOLITE-MACCS difference was lower than 7%. Despite some inaccuracies in ρ w retrieval, we demonstrate that the SPM concentration can be reliably estimated using OLI, MODIS and VIIRS, regardless of their differences in spatial and spectral resolutions. Match-ups between the OLI-derived SPM concentration and autonomous field measurements from the Loire and Gironde estuaries' monitoring networks provided satisfactory results. The multi-sensor approach together with the multi-conditional algorithm presented here can be applied to the latest generation of ocean color

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“…Although bacteria are known to play a key role in speciation, mobility, and bioavailability of As in the environment, they have never been considered in previous studies of As mobility in the Isle River system. Indeed, former investigations of As cycling were focused on geochemical studies (4,11,12,22,33).As(III)-oxidizing bacteria can contribute to a natural attenuation of As pollution by decreasing its bioavailability and can help remove As from mine wastewaters through bioprocessing (1, 2). Many As(III) oxidizers have been isolated from various environments, especially mesophilic ecosystems (3,5,8,16,25,27,32,38).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…Important variations in dissolved As concentrations are found in the Isle River and depend on the hydrogeological season, with maximum values in spring and summer generally detected during low-flow conditions (12,22), and probably on temperature-controlled microbial As(V) reduction and/or microbial dissolution of solid As carrier phases (22). Two toxic inorganic forms of As are usually detected in aquatic system: arsenite, As(III), which is found mainly under anaerobic conditions and is more mobile than arsenate, As(V), which typically occurs under aerobic conditions and tends to associate with oxyhydroxides and clay minerals (11,34).…”

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confidence: 99%

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Population Structure and Abundance of Arsenite-Oxidizing Bacteria along an Arsenic Pollution Gradient in Waters of the Upper Isle River Basin, France

Quéméneur

Cébron

Billard

et al. 2010

Appl Environ Microbiol

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Denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR (qPCR) were successfully developed to monitor functional aoxB genes as markers of aerobic arsenite oxidizers. DGGE profiles showed a shift in the structure of the aoxB-carrying bacterial population, composed of members of the Alpha-, Beta-and Gammaproteobacteria, depending on arsenic (As) and E h levels in Upper Isle River Basin waters. The highest aoxB gene densities were found in the most As-polluted oxic surface waters but without any significant correlation with environmental factors. Arsenite oxidizers seem to play a key role in As mobility in As-impacted waters.Arsenic (As) occurs naturally as a local geological constituent of the soils surrounding the Upper Isle River Basin (Massif Central, France) due to natural geochemical anomalies but is also released from Au/As deposits of disused gold mines (4,11,12,33). Important variations in dissolved As concentrations are found in the Isle River and depend on the hydrogeological season, with maximum values in spring and summer generally detected during low-flow conditions (12,22), and probably on temperature-controlled microbial As(V) reduction and/or microbial dissolution of solid As carrier phases (22). Two toxic inorganic forms of As are usually detected in aquatic system: arsenite, As(III), which is found mainly under anaerobic conditions and is more mobile than arsenate, As(V), which typically occurs under aerobic conditions and tends to associate with oxyhydroxides and clay minerals (11,34). Although bacteria are known to play a key role in speciation, mobility, and bioavailability of As in the environment, they have never been considered in previous studies of As mobility in the Isle River system. Indeed, former investigations of As cycling were focused on geochemical studies (4,11,12,22,33).As(III)-oxidizing bacteria can contribute to a natural attenuation of As pollution by decreasing its bioavailability and can help remove As from mine wastewaters through bioprocessing (1, 2). Many As(III) oxidizers have been isolated from various environments, especially mesophilic ecosystems (3,5,8,16,25,27,32,38). They belong to more than 25 genera, mainly of the Proteobacteria phylum (3, 32, 38), and are related to organisms unable to oxidize As(III) based on 16S rRNA phylogeny. Diverse primer sets have been successfully developed to specifically target the functional aoxB gene (9,14,17,25,26), encoding the large molybdenum-bearing catalytic subunit of As(III)-oxidase (EC 1.20.98.1), an enzyme of the dimethyl sulfoxide (DMSO) reductase family. Using cloning-sequencing approaches, the aoxB gene has proven to be a reliable molecular marker for diversity studies of the polyphyletic aerobic As(III) oxidizers in As-impacted soil and water systems (17, 25). The genetic fingerprinting denaturing gradient gel electrophoresis (DGGE) technique is one useful tool for spatial, temporal, and geographical monitoring of complex bacterial population structure (23, 24). Quantitative real-time PCR (qPCR) p...

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Seasonal variations and annual fluxes of arsenic in the Garonne, Dordogne and Isle Rivers, France

Cited by 68 publications

References 43 publications

Toward Sentinel-2 High Resolution Remote Sensing of Suspended Particulate Matter in Very Turbid Waters: SPOT4 (Take5) Experiment in the Loire and Gironde Estuaries

Toward Sentinel-2 High Resolution Remote Sensing of Suspended Particulate Matter in Very Turbid Waters: SPOT4 (Take5) Experiment in the Loire and Gironde Estuaries

Atmospheric Corrections and Multi-Conditional Algorithm for Multi-Sensor Remote Sensing of Suspended Particulate Matter in Low-to-High Turbidity Levels Coastal Waters

Population Structure and Abundance of Arsenite-Oxidizing Bacteria along an Arsenic Pollution Gradient in Waters of the Upper Isle River Basin, France

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