Naturally Occurring Asbestos in France: Geological Mapping, Mineral Characterization and Regulatory Developments

International audienceIn France, the asbestos banning is subject to a national decree (n° 96-1133), published in 1996. The regulatory texts and standards adopted to control this banning concern in particular asbestos-bearing manufactured products, but remain difficult to apply to asbestos-bearing natural materials (ie. rocks, soils). Considering problems related to such asbestos-bearing natural materials, the Ministry of Ecological and Solidary Transition has mandated the French Geological Survey to locate the impacted areas. Mappings were priority carried out in geological domains where NOA was predictable (French Alps, Corsica). These studies integrated field expertise, sampling and laboratory analyses, in order to characterize the potential of geological units to contain NOA. Furthermore, some expertises were carried out on geological formations exploited in France to produce aggregates. These studies concerned the quarries exploiting massive basic or ultrabasic rocks, likely to contain NOA, and quarries exploiting alluvium likely to contain asbestos-bearing rock pebbles. These studies highlight the difficulty of establishing robust diagnoses for natural materials. Indeed, distinction between cleavage fragments resulting from the fragmentation of non-asbestos particles and proper asbestos fibers is particularly problematic for laboratories. Thus, a recent study of the National Agency for Health Safety, Food, Environment and Work (2015) recommends to apply the asbestos regulation for elongated mineral particles (L/D > 3:1, L > 5 μm, D < 3 μm) with chemical composition corresponding to one of the five regulated amphibole species, irrespective of their mode of crystallization (asbestiform or non-asbestiform). The upcoming regulatory changes are part of a decree published in 2017, including the prior identification of asbestos in natural soils or rocks likely to be impacted by the execution of work. Specific protocols will be defined for sampling, analysis and characterization of natural materials that may contain asbestos

Combined electrochemical and biological treatment for pesticide degradation - Application to phosmet

International audienceThe aim of this study was to determine the feasibility of coupling an electrochemical process with a biological treatment in order to degrade phosmet, an organophosphorous pesticide. The absence of biodegradability of phosmet by Pseudomonas fluorescens and activated sludge was verified in our operational conditions. So, a conventional biological treatment is not appropriate for phosmet polluted effluents. Electrochemical behavior of phosmet was studied by cyclic voltammetry and the feasibility of an electrochemical pretreatment was thus demonstrated. Preliminary results with activated sludge showed a diminution of 26% for COD (chemical oxygen demand) measured when the electrolyzed solution was used as the sole carbon and nitrogen sources. When glucose and ammonium were added as supplementary carbon and nitrogen sources, the COD diminution reached 34% after 79 h of culture. This study demonstrates the feasibility of an electrochemical pre-treatment prior to biotreatment

False positive PCR detection of Tropheryma whipplei in the saliva of healthy people

<p>Abstract</p> <p>Background</p> <p><it>Tropheryma whipplei</it>, the agent of Whipple's disease (WD), has been recently isolated and the genomes of two isolates have been fully sequenced. Previous diagnosis tools for the diagnosis of the disease used sequence analysis of the 16S rRNA gene. Using this target gene, the high percentage of detection of the bacterium in saliva of healthy people was in contrast to the negative results obtained with specific target genes. The aim of our study was to compare previously published primers targeting the 16S rRNA gene to real-time PCR with Taqman* probes targeting specific repeat genes only found in the genome of <it>T. whipplei </it>in a series of 57 saliva from healthy people.</p> <p>Results</p> <p>Although the specific real-time PCR assays with both primers and probes were negative for all the samples, 13 out of 57 samples were positive with different primers previously reported targeting the 16S rRNA gene. Among the positive samples, 8 yielded a 231-bp sequence that was 99.1% identical to that of <it>Actinomyces odontolyticus</it>, 2 yielded a 226-bp that was 99.6% identical to that of <it>A. turicensis</it>, and 3 yielded a 160-bp sequence that was 98.5% identical to that of <it>Capnocytophaga gingivalis</it>. We found that the <it>C. gingivalis </it>and <it>A. odontolyticus </it>16S rRNA sequences obtained in our study share more than 80% homology with the corresponding 16S rRNA sequences of the <it>T. whipplei </it>genomes especially at 5' and 3' end.</p> <p>Conclusion</p> <p>Asymptomatic carriers of <it>T. whipplei </it>in saliva may exist but their prevalence is much lower than those previously reported. Testing the specificity of designed primers is critical to avoid false positive detection of <it>T. whipplei</it>. In atypical case we recommend to test two different specific target genes before concluding.</p

Direct electrochemical oxidation of a pesticide, 2,4-dichlorophenoxyacetic acid, at the surface of a graphite felt electrode: Biodegradability improvement

International audiencePesticides' biorecalcitrance can be related to the presence of a complex aromatic chains or of specific bonds, such as halogenated bonds, which are the most widespread. In order to treat this pollution at its source, namely in the case of highly concentrated solutions, selective processes, such as electrochemical processes, can appear especially relevant to avoid the possible generation of toxic degradation products and to improve biodegradability in view of a subsequent biological mineralization. 2,4-D was found to be electroactive in oxidation, but not in reduction, and the absence of hydroxyl radicals formation during the electrochemical step was demonstrated, showing that the pretreatment can be considered as a "direct" electrochemical process instead of an advanced electrochemical oxidation process. The presence of several degradation products in the oxidized effluent showed that the pretreatment was not as selective as expected. However, the relevance of the proposed combined process was confirmed since the overall mineralization yield was close to 93%

Reductive dehalogenation of 1,3-dichloropropane by a [Ni(tetramethylcyclam)]Br2-Nafion modified electrode

International audienceDechlorination reaction of 1,3-dichloropropane, a contaminant solvent, was investigated by electrochemical reduction in aqueous medium using a Ni(tmc)Br2 complex, known as effective catalyst in dehalogenation reactions. The catalytic activity of the complex was first investigated by cyclic voltammetry and flow homogeneous redox catalysis using a graphite felt as working electrode. A total degradation of 1,3-dichloropropane was obtained after 5 h of electrolysis with a substrate/catalyst ratio of 2.3. The concentration of chloride ions determined by ion chromatography analysis showed a dechlorination yield of 98%. The complex was then immobilized on the graphite felt electrode in a Nafion® film. Flow heterogeneous catalytic reduction of 1,3-dichloropropane was then carried out with the [Ni(tmc)]Br2-modified Nafion® electrode. GC analyses underlined the total degradation of the substrate in only 3.5 h with a substrate/catalyst ratio of 100. A dechlorination yield of 80% was obtained, as seen with ion chromatography analyses of chloride ion. Comparison of both homogeneous and heterogeneous reactions highlighted the interest of the [Ni(tmc)]Br2-modified Nafion® electrode that led to a higher stability of the catalyst with a turnover number of 180 and a higher current efficiency

Modern pollen assemblages from grazed vegetation in the western Pyrenees, France: a numerical tool for more precise reconstruction of past cultural landscapes

International audienceModern pollen assemblages from grazed vegetation in the Pyrenees Mountains (France) were studied with the aim of providing a calibrated model for reconstructing past pastoral activities. The modern analogues were selected to cover the major gradients of grazing pressure and degree of openness. The vegetation was surveyed by means of the synusial integrated method, assessing the structure and the patchiness of the pastoral phytoceonoses. A correlative model (Redundancy analysis) was devised relating 61 modern pollen spectra with 37 explanatory vegetation and land-use variables. It was shown that wooded, open grazed and nitrophilous sites are clearly separated from one another and that the model can be simplified using three relevant vegetation types as explanatory variables: dry heathland, semi-open oak forest and overgrazed community, respectively related to gradients of openness, soil richness and grazing pressure. When reconstructing past pastoral activities with fossil pollen spectra, it is important to consider scale-dependent influences of plant species. Low frequencies of well-dispersed taxa such as Artemisia, Chenopodiaceae, Plantago lanceolata and Plantago major/media must be interpreted with care since they reflect more regional, rather than local, input into the pastoral landscape. In contrast, the simultaneous occurrence of Asteroideae, Cichorioideae, Cirsium-type, Galium-type, Ranunculaceae, Stellaria-type and Potentilla-type pollen is clearly related to grazing on a local scale. Calculation of Davis indices also shows that Cichorioideae, Galium-type and Potentilla-type indicate the very local presence of the corresponding plants. These pastoral plant indicators may have a limited geographical validity, ie, mountainous regions with crystalline bedrock, which may indeed also provide the framework for the application to fossil spectra of the modern pollen/vegetation/land-use models presented here

Suivi rhéologique du processus d'agrégation de la protéine tau

International audienceAlzheimer's disease is one of thirty pathology called conformational disease that are characterized by errors folding and assembly of protein. In Alzheimer's disease, tau protein and amyloid beta peptide are responsible of the neuronal degeneration. Understanding these mechanisms and diagnosis are closely linked to the availability of an efficient analytical concept for monitoring ex vivo self-assembly of proteins. To understand the aggregation's mechanism, a microsystem is developed for the detection of protein tau based on the micro-rheological followed by high frequency ultrasonic waves. The sensor used is a TSM (Thickness Shear Mode) resonator operating in shear mode at a fundamental frequency of 5MHz. In contact with the fluid to be characterized, the sensor generate shear waves, which are measured in reflection through instrumentation developed in the laboratory. From the measurement of the complex impedance of quartz with a network analyzer, the extraction of G' (elastic modulus) and G'' (viscous modulus) is possible. Initial results indicate that our sensor can quantify, by viscosity, concentration variations of a peptide sequence of tau protein, and can differentiate, by plasticity, the conformational state.  </p

Combined process for removal of tetracycline antibiotic - Coupling pre-treatment with a nickel-modified graphite felt electrode and a biological treatment.

International audienceBiodegradability improvement of tetracycline-contg. solns. after an electrochem. pre-treatment was examd. Cyclic voltammetry with a nickel electrode revealed a significant electrochem. activity of tetracycline, in both oxidn. and redn. Electrochem. treatment was therefore performed in a home-made flow cell using a nickel-modified graphite felt electrode as the working electrode. Optimal conditions, namely 100 mg l-1 initial tetracycline, above 0.45 V potential, and between 1 and 6 mL min-1 flow rate, led to a more than 99% conversion yield of tetracycline in oxidn. in alk. conditions, after only a single pass through the percolation cell. However, total org. carbon (TOC) analyses revealed a low mineralization level, i.e., always below 31%, underscoring the importance of a combined electrochem. and biol. treatment. This was confirmed by the favorable trends of the COD/TOC ratio, decreasing from 2.7 to 1.9, and the av. oxidn. state, increasing from 0.044 to 1.15, before and after oxidn. pretreatment at 0.7 V and 3 mL min-1 flow rate. Electrolyzed solns. appeared biodegradable, since BOD5/COD increased from 0 to 0.46 for untreated and pretreated TC at 0.7 V/SCE. Biol. treatment showed only biosorption for non-pretreated tetracycline, while after 11.5 days of culture, the mineralization of solns. electrolyzed in oxidn. was 54%, leading to a 69% overall TOC decrease during the combined process

A history of long-term human-environment interactions in the French Pyrenees inferred from the pollen data

International audienceOver the last decade, several research programs have been involved in studying the socioecological history of the Pyrenean Mountains using sedimentary records preserved in lakes and bogs. Their main focus was on understanding human exploitation of natural resources and its environmental consequences. Recovering these “memories” buried for thousands of years in sediments requires interdisciplinary efforts dealing with the analysis of a large number of bio-indicators. The study of those bio-indicators has become a multi-proxy process which combines the classicalstudy of fossil pollen and spores with macro-charcoal (size >150 m m) and nonpollen palynomorphs (algae, fungal spores, etc.) data

Système d'aide à la décision pour la limitation des risques d'inondation dans les agglomérations urbaines méditerranéennes

97 pagesSupport system for managers and representatives for flood risk mitigation in Mediterranean urban areas. The objective is to propose a tool for the space management dedicated to decision makers which could detect urban areas subjected to flood risk in order to act on urban public policies in the field of construction, traffic management and types of urban organisation. The method is the modelling of risk spatialisation and evolutio