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Nanomaterials and biorefineries : inspiring some safety thoughts
No full textInternational audienceThis presentation aims essentially at examining and discussing the potential nanosafety issues pertaining to the production of advanced bio-based chemicals that might impact their development. Nanomaterials are now used for energy storage and conversion, the production of various added-value chemicals from biomass including biochemicals, biomaterials and biofuels. Several nanomaterials are also synthetized from renewable and highly abundant feedstocks like carbonaceous nanomaterials (fullerene, carbon nanotubes) or nanocellulose. The use of nanomaterials has paved the road of multiple sustainable innovations and is perceived as rather safe because "green", i.e. avoiding the use and generation of toxic and polluting substances [1]. Safety concerns about these materials were raised by the bio-community only recently [2]. It is however important to have a closer look at their potential environmental and occupational risks. Concerning hazards related to nanomaterials, their potential toxicity is the first thing that comes to mind. However, toxicity of these materials is not the only potential hazard. Thermal stability, flammability and dust explosivity also have to be assessed as several types of nanomaterials are combustible powdered materials that may accidentally turn into explosible atmospheres. Historically, literature studies concerning the evaluation of explosion and flammability hazards of powders were essentially but several investigations are being carried out also on nanomaterials and several questions are raised through EU research projects as well as in the European Standardization Committees, CEN TC 352. Testing strategies that may be used for screening purposes at pre-commercial stages should also be discussed as they require dedicated facilities such as the S-NANO Platform at INERIS. The hazard characterization of the nanomaterials issued from bio-engineering is essential to ensure that their market deployment is not delayed by uncertainties related to their safety. This presentation gives a brief overview of the current challenges and knowledge on the topic as well as some considerations about the concepts related to the inherent safety design of these materials
Compréhension et prédiction des mécanismes d’incompatibilités chimiques à l’aide de la DFT
No full textInternational audienceLe nitrate d'ammonium (NA) est largement utilisé comme engrais et explosif. En raison de son danger physique, le nitrate d'ammonium est classé comme agent oxydant selon le UN Recommendation on the Transport of Dangerous Goods. NA est incompatible avec une large gamme de substances comme les composés chlorés, les composés organiques, les nitrites (NaNO2), etc... Au cours des dernières années, l'INERIS, en collaboration avec Chimie ParisTech, a développé une approche de modélisation moléculaire basée sur la Théorie de la Fonctionnelle de la Densité (DFT) pour compléter et améliorer les connaissances expérimentales sur les incompatibilités chimiques du nitrate d'ammonium. Cette approche a permis de mieux comprendre les voies de réaction possibles entre le nitrate d'ammonium et des composés incompatibles, en termes d'énergie et de produits formés1,2,3. Actuellement, la contribution proposée présentera des travaux en cours visant le développement d'un outil de prédiction capable d'identifier différents comportements de contaminants en contact avec NA (inerte, stabilisateur ou promoteur) en se concentrant sur les étapes clés des voies réactionnelles. Les deux premiers contaminants étudiés au cours de cette recherche sont le carbonate de calcium CaCO3, utilisé comme stabilisant pour le nitrate d'ammonium, et le sulfate de calcium CaSO4 utilisé comme inerte. Il a été clarifié que les deux sels ont un mécanisme de réaction similaire avec NA et les résultats sont en accord avec des études expérimentales 4,5. Ces résultats ont démontré la capacité de l'approche à caractériser le potentiel de stabilisation d'un contaminant. Des travaux sont également en cours pour proposer une approche de dépistage simplifiée permettant d'identifier la nature des contaminants (compatibles, stabilisants, incompatibles) à partir d'indicateurs structurels et / ou d'études mécaniques simplifiées
PBPK modeling of zebrafish embryo for reprotoxicity assessment of valproic acid and some of its analogs
No full textInternational audienceIntroduction: Understanding and predicting chemical effects on development and reproduction is a complex challenge. The zebrafish embryo is an in vitro test system increasingly used for its transparency, short development time, easy husbandry and gene homologies with humans. Objectives: To better explain and predict developmental toxic effects observed in zebrafish embryo, we are developing a generic physiologically-based pharmacokinetic (PBPK) model to predict target organ concentrations of neutral or ionizable chemicals. We present an application of the model in the assessment of the teratogenicity of valproic acid (VPA) and nine analogs. Material and methods: Quasi steady-state distribution of chemicals is modeled in ten embryo organs, and in two sub-cellular organelles: lysosomes and mitochondria. The partition coefficients between the organs or organelles and the culture medium depend on physico-chemical properties of the substances. Organ volumes grow over the first 5 days of life. Liver metabolism can be linear or saturable. For VPA and analogs, metabolic parameters were estimated by Bayesian fitting of the model to data on culture medium and embryo concentrations during repeated dosing. Results: The kinetic data were reasonably well fitted by the model (Figure 1), even though residual uncertainty was substantial. Linear clearance estimates for VPA and analogs were around 10-10 to 10-11L/min, which for an embryo volume of 3×10-7L, correspond to half-lives of about 11.5h. Embryo organ concentrations were used to calculate dose-response for general lethality and heart defect-caused deaths. Naïve dose-responses were also calculated using nominal dose. Using target organ concentrations shifts substantially the magnitude of doseresponse parameters and the relative toxicity ranking of the VPA analogs studied (Figure 2). Conclusion: The model can be used to relate zebrafish effects observed in vitro to cellular exposures. It should improve the translation of in vitro zebrafish data to humans for safety assessment
Opening science to civic society: the case of stakeholder committees in research institutions in France
No full textInternational audienceThis paper draws on the analysis of an institutional innovation: the creation of stakeholder committees in public research organisations. In France, this innovation dates back from the 2000's. The official objective is to open up the governance to members of the 'civic society' in order to increase research pluralism and to improve the alignment between 'societal needs' and production of scientific and technical knowledge. So far, such opening up has not been studied. As these stakeholder committees have now ten years experiences, successes and failures, the time is ripe to thoroughly analyse this institutional innovation. Can such committees influence knowledge production and orientations? Does it change the sociology of people involved in scientific decisions? What practices does it promote in scientific institutions? To explore those general questions, this paper pays attention "to rules and rule making" of stakeholder committees (Epstein 1998, Fischer 2000, Weisman 1998, Frickel & Moore 2005). Here we focus on specific rules: accreditation as a representative (people and organizations) - hearing (roles and knowledges) - file process - agendas setting - relationships to other institutional governance parts. Our comparative study draws on the analysis of 4 stakeholder committees settled as part of scientific governance in French expertise and research institutions in sanitary and environmental fields. Qualitative and quantitative data were collected by participant observatory, interviews and archival work. The results shows that public engagement is highly shaped by rules processes
NANOWET project : characterization of nanoparticle emission from high temperature incineration of nano-/halogen-/sulfur-containing wastes and performances of wet-scrubber units
No full textInternational audienceIn order to address the health and environmental problems potentially raised by the incineration of nanowastes, the NanoWet project (supported by the French Agency for Environment and Energy Management -ADEME- CORTEA funding scheme - Grant No. 1581C0096) focuses on the treatment of nanowastes by high-Temperature (T) incineration required when halogen- and sulfur-containing wastes are disposed of. The objectives of the project are i) to assess the effect of both high postcombustion T of 1,100°C and presence of acid gases in raw fumes, on the potential emission and behaviour of nanoparticles originating from nanowaste incineration, and ii) to quantify downstream nanoparticle capture by the wet-scrubbers equipping the fume treatment lines before the exhaust. First, three wastes were selected and characterized: PDMS waste from polyorganosiloxane polymerization processes containing 24.4% dwt of SiO2 nano-fillers (waste previously studied in the framework of NanoFlueGas project [1]); soft PVC from flexible PolyVinyl Chloride production containing 36% dwt of Cl and nano-fillers mainly composed of TiO2; Resin waste from soiled strong acid cation exchange resins of sulfonic type exhibiting 15.4% dwt of S, but no nano-filler type identified. A lab-scale incinerator device composed of a tubular horizontal furnace was designed to operate in representative key conditions of a high-T incineration process dedicated to industrial wastes (T of 1,100°C in both combustion zones, residence time at least of two seconds in the post-combustion zone, air excess from primary and secondary air flows contributing to achieve adequate turbulence conditions). A fume sampling device allows to characterize O2, CO2, CO, SO2, HCl contents as well as particulate matter concentrations in various granulometric ranges. When present, the solid residue after incineration is analyzed to estimate the presence of nano-fillers. Incineration tests were carried out in single-waste or mixed loads. The interactions between the PDMS nanowaste and the halogen- /sulfur- wastes will be discussed in terms of behavior/fate of particles in the fumes. In order to study the performances of wet-scrubbers regarding nanoparticle capture, a lab-scale spraying scrubber will be developed based on real data inferred through a measurement campaign which was carried out on a full-scale industrial unit (TREDI - Groupe Séché Environnement), out of specific incineration of nanowastes but in prevalence condition of halogen-/sulfur-containing wastes. In particular, the particle concentration and size distribution were measured in the core-process, at the inlet of the wet-scrubber columns (after dedusting by electrofiltration). The lab-scale spraying scrubber will thus operate in realistic conditions of temperature, humidity, particle load, liquid/gas ratio, height/diameter ratio of the column, residence time, turbulent flow regime, droplet diameter and relative velocity between particles and droplets
Post-mining management in France. Implementation of a systematic prevention policy
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Vulnérabilité des structures. Description spatiale du chargement issu d’explosions accidentelles : mise en évidence d’une réflexion de Mach
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Les échantillonneurs passifs de flux pour la mesure de la qualité des eaux souterraines
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Rôle du transport particulaire lié à la déstructuration de gypses poreux dans le développement de cavités de dissolution
No full textInternational audienceAfin d’améliorer la connaissance sur les mécanismes de dissolution et de déstabilisation des vides, des travaux de recherche ont été entrepris à l’Ineris en partenariat avec le Centre Géosciences Mines-ParisTech. Cette collaboration scientifique s’intègre au marché de recherche et développement sur les processus de dissolution du gypse réalisé pour le compte de la Société du Grand Paris (SGP). Ce travail vise principalement à étudier les couplages hydrodynamiques, chimiques et mécaniques intervenant dans les processus de dissolution du gypse. Différents protocoles expérimentaux ont été mis au point afin d’évaluer la variabilité du taux de dissolution du gypse en fonction des faciès et des propriétés physiques du fluide sous-saturé et de vérifier si la nature pétrophysique et pétrographique du gypse influence ses propriétés de dissolution