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Malherbe J.,Laboratoire Of Chimie Analytique Bio Inorganique Et Environnement | Malherbe J.,U.S. National Institute of Standards and Technology | Isaure M.-P.,Laboratoire Of Chimie Analytique Bio Inorganique Et Environnement | Seby F.,Ultra Traces Analyses Aquitaine UT2A | And 9 more authors.
Environmental Science and Technology | Year: 2011

Hexavalent chromium (Cr(VI)) occurrence in soils is generally determined using an extraction step to transfer it to the liquid phase where it is more easily detected and quantified. In this work, the performance of the most common extraction procedure (EPA Method 3060A) using NaOH-Na2CO3 solutions is evaluated using X-ray absorption near edge structure spectroscopy (XANES), which enables the quantification of Cr(VI) directly in the solid state. Results obtained with both methods were compared for three solid samples with different matrices: a soil containing chromite ore processing residue (COPR), a loamy soil, and a paint sludge. Results showed that Cr(VI) contents determined by the two methods differ significantly, and that the EPA Method 3060A procedure underestimated the Cr(VI) content in all studied samples. The underestimation is particularly pronounced for COPR. Low extraction yield for EPA Method 3060A was found to be the main reason. The Cr(VI) present in COPR was found to be more concentrated in magnetic phases. This work provides new XANES analyses of SRM 2701 and its extraction residues for the purpose of benchmarking EPA 3060A performance. © 2011 American Chemical Society. Source


Plewniak F.,University of Strasbourg | Koechler S.,University of Strasbourg | Navet B.,University of Strasbourg | Dugat-Bony E.,CNRS Microorganisms Laboratory: Genome and Environment | And 6 more authors.
Molecular Ecology | Year: 2013

Microorganisms dwelling in sediments have a crucial role in biogeochemical cycles and are expected to have a strong influence on the cycle of arsenic, a metalloid responsible for severe water pollution and presenting major health risks for human populations. We present here a metagenomic study of the sediment from two harbours on the Mediterranean French coast, l'Estaque and St Mandrier. The first site is highly polluted with arsenic and heavy metals, while the arsenic concentration in the second site is below toxicity levels. The goal of this study was to elucidate the potential impact of the microbial community on the chemical parameters observed in complementary geochemical studies performed on the same sites. The metagenomic sequences, along with those from four publicly available metagenomes used as control data sets, were analysed with the RAMMCAP workflow. The resulting functional profiles were compared to determine the over-represented Gene Ontology categories in the metagenomes of interest. Categories related to arsenic resistance and dissimilatory sulphate reduction were over-represented in l'Estaque. More importantly, despite very similar profiles, the identification of specific sequence markers for sulphate-reducing bacteria and sulphur-oxidizing bacteria showed that sulphate reduction was significantly more associated with l'Estaque than with St Mandrier. We propose that biotic sulphate reduction, arsenate reduction and fermentation may together explain the higher mobility of arsenic observed in l'Estaque in previous physico-chemical studies of this site. This study also demonstrates that it is possible to draw sound conclusions from comparing complex and similar unassembled metagenomes at the functional level, even with very low sequence coverage. © 2013 John Wiley & Sons Ltd. Source


Menta M.,University of Pau and Pays de lAdour | Frayret J.,University of Pau and Pays de lAdour | Grassl B.,University of Pau and Pays de lAdour | Gleyzes C.,Ultra Traces Analyses Aquitaine UT2A | And 2 more authors.
Journal of Cleaner Production | Year: 2015

In the metal finishing or aeronautical industries, efficient degreasing of metallic alloy surfaces is an essential step. This step was first performed with halogenated solvents. Legislation has involved since 1999 their replacement with green cleaners due to the hazardous effects of solvents on human health and on environment. Aqueous cleaners, commonly called detergents, are widely used as an alternative. The monitoring of such degreasing baths is usually realized by alkaline titration or conductimetry. However these techniques do not provide significant information on the state of degreasing baths. In this study a new method is proposed using dynamic light scattering (DLS). This technique can evaluate the size of the micelles formed in the degreasing bath. The free and "full of oil" micelles can be identified and quantified due to their different sizes. The contamination rate and the loss of detergent all along the use of the bath can be determined with these new indicators. After a validation step with prepared degreasing solutions, this method has allowed monitoring precisely industrial degreasing baths, reducing the frequency of the baths replacement, the volume of aqueous effluents and optimizing baths management. © 2015 Elsevier Ltd. Source


Menta M.,University of Pau and Pays de lAdour | Frayret J.,University of Pau and Pays de lAdour | Gleyzes C.,Ultra Traces Analyses Aquitaine UT2A | Castetbon A.,University of Pau and Pays de lAdour | Potin-Gautier M.,University of Pau and Pays de lAdour
Journal of Cleaner Production | Year: 2012

In the metal finishing or aeronautical industries, efficient degreasing of metallic alloy surfaces is an essential step. This step was first performed with halogenated solvents. Legislation has recently required their replacement with green cleaners due to the hazardous effects of the solvents on human health and on the environment. The industrial partners of the study chose to use aqueous cleaners, commonly called detergents, as an alternative. The monitoring of these baths is important to evaluate degreasing power on soiled alloy pieces. This study is focused on the evaluation of typical analytical tools recommended by providers (alkaline titration and electrical conductivity measurements) to perform degreasing bath monitoring. The results demonstrate that these techniques do not provide significant information on the state of the degreasing bath if they are used alone. Indeed, investigations performed on prepared samples simulating a degreasing bath demonstrate that alkaline titration is mainly representative of the oil in solution, whereas electrical conductivity measurements are influenced by oil and surfactants or detergents. Detergents are surfactants that possess adapted characteristics for detergency. From these results, an alternative methodology has been developed to monitor industrial samples, and conductivity measurements were used as age indicators for the rinsing baths. © 2011 Elsevier Ltd. All rights reserved. Source


Unceta N.,University of the Basque Country | Seby F.,Ultra Traces Analyses Aquitaine UT2A | Malherbe J.,University of Pau and Pays de lAdour | Donard O.F.X.,University of Pau and Pays de lAdour
Analytical and Bioanalytical Chemistry | Year: 2010

In recent years, the extensive use of chromium in industrial processes has led to the promotion of several directives and recommendations by the European Union, that try to limit and regulate the presence of Cr(VI) in the environment and to protect industrial workers using chromium and end-users of manufactured products. As a consequence, new standard methods and analytical procedures have been published at the EU level for Cr(VI) determination in soil, sludge, sediment, and similar waste materials, workplace atmospheres, cement, packaging materials, industrially produced samples, and corrosion-protection layers on some components of vehicles and electrical and electronic equipment. The objective of this article is to summarize the different directives and recommendations and to critically review the currently existing standard methods and the methods published in the literature for chromium speciation in the above mentioned solid matrices, putting the emphasis on the different extraction procedures which have been developed for each matrix. Particular attention has been paid to Cr(III) and Cr (VI) inter-conversions that can occur during extraction and efforts to minimize these unwanted reactions. Although the use of NaOH-Na2CO3 solutions with hot plate extraction seems to be the more widespread procedure, species transformation can still occur and several studies suggest that speciated isotope-dilution mass spectrometry (SIDMS) could be a suitable tool for correction of these interconversions. Besides, recent studies have proved the role of Cr(III) in chromium toxicology. As a consequence, the authors suggest an update of standard methods in the near future. © Springer-Verlag 2010. Source

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