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Toxicocinétique du perfluorooctane sulfonate chez la truite arc en ciel (Onchorynchus mykiss) à différentes température : étude à l'aide d'un modèle à base physiologique
No full text[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiplesInternational audienceThis study is part of a project aiming to improve our understanding of the toxicokinetics of perfluoro-alkyl substances (- PFOS, perfluorohexane sulfonate and perfluorononanoate - PFNA) in fish, using the rainbow trout (Onchorynchus mykiss) as model species. The project involves a combination of dietary exposure experiments and physiologically-based toxicokinetic (PBTK) modelling. We developed first a 10-compartment PBTK model to elucidate PFOS kinetics in adult rainbow trout. This PBTK model included various physiological characteristics: blood perfusion to each organ, plasmatic fraction, PFOS free fraction, and growth of individuals. The parameters were optimized using Bayesian inference. This development was based on an experimental dataset, where fish were first fed daily with spiked food, and allowed to depurate for an equivalent duration [1]. We evaluated the relative importance of different absorption as well as elimination routes, and the role of the entero-hepatic cycle. This model was then used to explore the effects of temperature on PFOS toxicokinetics. The modulation of physiological processes induced by temperature was introduced into the model structure thanks to Arrhenius law. These processes included food absorption, ventilation rate, growth, cardiac output, urinary, biliary and fecal clearances, and relative blood flow distribution to organs. We hypothesized that temperature could also affect PFOS tissue:plasma or tissue:blood partition coefficients. Simulations were performed for water temperatures of 7°C, 11 °C, 15 °C and 19°C and compared to experimental data [1, 2]. The simulation having the lowest Root Mean Squared Error was obtained when all physiological processes were modulated according to temperature. Overall, the model outcomes suggest that PFOS toxicokinetics was more affected by temperature induced changes in partition coefficients than in fish physiology. A sensitivity analysis is ongoing in order to confirm and refine this result. [1] Vidal A, Lafay F, Daniele G, Vulliet E, Rochard E, Garric J, Babut M. in press. Does water temperature influence the distribution and elimination of perfluorinated substances in rainbow trout (Oncorhynchus mykiss)? Environ Sci Pollut Res. [2] Goeritz I, Falk S, Stahl T, Schäfers C, Schlechtriem C. 2013. Biomagnification and tissue distribution of perfluoroalkyl substances (PFASs) in market-size rainbow trout (Oncorhynchus mykiss). Environ Toxicol Chem 32:2078-2088
Data fusion for air quality mapping using sensor data : feasibility and added-value through an application in Nantes
No full textInternational audienceData fusion for air quality mapping using sensor data: feasibility and added-value through an application in NantesaThe recent technological developments and the increased interest for public information lead to a fast-growing use of microsensors for air quality monitoring. Measurement campaigns are conducted to assess the potential of these low-cost instruments by deploying fixed sensors (e.g. on top of buildings, street lights or reference stations) and/or mobile sensors (e.g. on top of cars, bikes, or carried by citizens). These experiments allow to measure pollutant concentrations at high resolution in space and time. The large amount of collected information offers new opportunities of developments in air quality modelling and mapping. This work aims to take the best of these sensors despite the related measurement uncertainty to produce urban air pollution maps at fine spatial and temporal resolution. A geostatistical methodology (data fusion) is presented, which uses sensor observations as well as dispersion model outputs. It is applied to PM10 data in the French city of Nantes. It involves new challenges such as the consideration of the quick change of the sensor location if it is mobile, the temporal variability of the measurements, the analysis of numerous and heterogeneous data, the spatial representativeness of the measurements and the measurement uncertainties. Also, efforts still need to be done on the sampling design to ensure appropriate spatial coverage of the considered domain and get more accurate estimates
Exploratory analysis of fire risks pertaining to furanic platform chemicals
No full textInternational audienc
Proposition of threshold for waste contaminated with mercury (compounds) in application of the Minamata convention on mercury and impact assessment
No full textInternational audienceThe Minamata Convention on Mercury is a global treaty to protect human health and the environment from the adverse effects of mercury. Environmentally sound management of waste is under discussion. This note proposes a threshold for waste of category c) Contaminated with mercury or mercury compounds to be disposed of (Article 11 of the Convention), using the Globally Harmonized System of classification and labelling of chemicals of the United Nations (GHS - UNEP 2017). Mercury and mercury compounds are classified as substances for the physical, health and environmental hazards categories. The thresholds of mercury and mercury compounds classifying a mixture as hazardous for the different hazard categories (physical, health, environmental) are “Presence”, >0.1% and >0.0025% (25 mg mercury/kg of waste) respectively. For impact assessment, this threshold is then compared with large data set of hazardous (793 data), potentially hazardous (depending on the concentration of hazardous substances) (55 data), as well as natural or non-polluted anthropized media (composts, sediments, agricultural soils) (21 784 data) from France. This demonstrates that 75% of the hazardous waste have higher total mercury concentration, that potentially hazardous waste samples have lower concentrations, and that all composts, agricultural soils and marine sediments and 99% of the fluvial sediments have lower concentrations. So, this threshold will not classify common industrial waste or natural media as requiring special treatment for safe disposal, but well a large part of industrial hazardous waste
Overpressure Effects from Propane Detonation : Comparison of Simulation Results with Experimental Data
No full textInternational audienceAccidental gas explosion is a standard scenario considered in risk assessment for process industries. Blast walls or barriers are an efficient way to reduce the effects of pressure waves originated from an explosion. However, the proper design of a blast wall requires heavy investigation considering real accidental scenarios. CFD-based method can be used for a parametric investigation and for design optimization instead of experimental investigations. Nevertheless, the first CFD codes must be validated versus corresponding experimental data. The purpose of this paper is to present comparison of CFD simulations of propane/oxygen detonation and experimental measurements for small scale explosions
Aérosolisation de particules de carbure de silicium sur des périodes longues
No full textInternational audienceSilicon carbide (SiC) particles used in long-duration industrial applications releases potentially hazardous dust which can also change the bulk material quality. However, most dustiness tests do not study dust released over long durations nor do they measure the effect of dust generation on the bulk powder as they emulate applications lasting for short duration (few seconds to minutes) which has minimal effect on the bulk sample. In this study, we test the number and mass dustiness of two different samples of SiC powders with median particle sizes (x50) of 66 µm and 38 µm, over six hours using a vortex shaker. The dust generation mechanism might include the release of aerosols due to the attrition of particles owing to inter-particle and particle-wall impaction. This study emphasizes the need for long duration dustiness tests for hard materials like SiC and characterization for change in bulk material properties due to dust generation and release. Furthermore, the results can aid in selecting the bulk material for long-term applications based on dustiness.Certaines applications industrielles utilisent de la poudre de carbure de silicium sur des durées allant de plusieurs heures à plusieurs mois. De telles durées induisent des problématiques d'émission (exposition des opérateurs, rejets à l'environnement) mais aussi de modification de la poudre elle-même. Ces problématiques sont très peu considérées à ce-jour, les tests de pulvérulence étant principalement centrés sur les quantités de matière émises, et ce pour des durées plus courtes. Les résultats présentés ici portent sur l'étude par agitateur vortex [3, 4] de la pulvérulence en masse et en nombre de deux types de poudre de SiC de diamètre médian (x50) de 66 µm et 38 µm, sur des périodes de 6 heures. Le mécanisme de génération de poussières peut comprendre la libération d'aérosol due à l'attrition des particules due à l'impaction entre particules et à la paroi des particules. Cette étude souligne la nécessité de procéder à des essais à long terme sur la poussière pour les matériaux durs comme le SiC et à la caractérisation des propriétés des matériaux en vrac en raison de la génération et de la libération de poussières. En outre, les résultats peuvent être trouvés dans le matériau en vrac pour des applications à long terme basées sur la poussière
Resilience, reliability, safety : multilevel research challenges
No full textInternational audienceThis chapter contributes to current research on resilience by considering two aspects of this topic. The first describes the popularity of resilience as a product of a shift of erawhich creates a degree of uncertainty about the future in several domains of concern in a globalised context, and how this notion has also travelled in the field of safety. The second part addresses the cognitive, institutional, methodological, empirical and theoretical challenges of interdisciplinary multilevel safety research
Storytelling or theory building? Hopkins’ sociology of safety
No full textInternational audienceIn the past two decades, Andrew Hopkins has been a very successful analyst of technological disasters and an acclaimed storyteller. In this article, I argue that he is also a theorist, and that he has developed over 40 years a normative sociological model of safety for studying major events. To do so, I first situate his contribution through a historical perspective going back to the 1970s and 1980s, a time during which Hopkins established core elements of a research program on catastrophic events subsequently deployed in late the 1990s onwards. Initially inspired in the 1970s and 1980s by the crime of the powerful, white-collar crime literature and a Marxist socio-legal perspective of society, he developed what I define as a white-collar crime accident model (WCC-AM). He then moves in the 1990s and 2000s on to a more organisational and practical sociology of safety elaborated in his retrospective accounts of disasters. To ground this assertion, I explain how his storytelling success results from the invention of a specific narrative structure which is based on a repeated sequence of description (1), assumption (2), explanation (3), comparison (4), recommendation (5) and counterfactual reasoning (6), applied to many articulated topics. From there, I extract a normative sociological model of safety built over two decades, and then discuss some of the findings of this study
Air pollution modeling and exposure assessment during pregnancy in the French Longitudinal Study of Children (ELFE)
No full textInternational audienceWe developed a nation-wide exposure model to NO2, PM10 and PM2.5 at a fine spatial and temporal resolution for France in order to study air pollutants exposure during pregnancy for the French Longitudinal Study of Children (ELFE). The exposure to air pollutants was estimated daily for years 2010 and 2011 by combining three simulation models at the national and regional scale (CHIMERE) and at the local urban scale (ADMS-Urban or SIRANE). The spatial resolution was 4 km for the national scale model, 3–4 km for regional models and from 10 to 200 m for urban-scale models. We developed a confidence index (from 0 to 10) based on the target plot to identify the best model to estimate exposure for a given address, year and pollutant. Air pollution exposure during pregnancy was then estimated using each modeling scale for the 17,427 women participating in the ELFE cohort. We described the exposure of the women during different time windows of pregnancy using each of the three models and using the most suitable model as estimated by the confidence index. The exposure estimates obtained from the three models were quite similar and highly correlated (spearman correlation between 0.64 and 0.96), especially for the national and regional models. For NO2 and PM10 predicted by the urban models, the minimum values were lower and the maximum values and the variability were higher, compared to the regional and national models. The averaged confidence indexes were comprised between 5.6 and 8 depending on the pollutant, year and exposure model considered. The best confidence index was observed for urban modeling (10) and the lowest for the regional modeling (0). In average during pregnancy, using the most suitable model, women were exposed to 21 μg/m3 for NO2, 16 μg/m3 for PM2.5 and 24 μg/m3 for PM10. To our knowledge, this is the first study combining three modeling tools available at different scales to estimate NO2, PM10 and PM2.5 concentrations at a fine spatial and temporal resolution over a large geographical area. The confidence index provides guidance in the choice of the exposure model. These exposure estimates will be used to investigate potential effects of air pollutants on the pregnant woman health and on health of the fetus and development of the child
Modeling the effect of non-ideality, dynamic mass transfer and viscosity on SOA formation in a 3-D air quality model
No full textInternational audienceIn this study, assumptions (ideality and thermodynamic equilibrium) commonly made in three-dimensional (3-D) air quality models were reconsidered to evaluate their impacts on secondary organic aerosol (SOA) formation over Europe. To investigate the effects of non-ideality, dynamic mass transfer and aerosol viscosity on the SOA formation, the Secondary Organic Aerosol Processor (SOAP) model was implemented in the 3-D air quality model Polyphemus. This study presents the first 3-D modeling simulation which describes the impact of aerosol viscosity on the SOA formation. The model uses either the equilibrium approach or the dynamic approach with a method specially designed for 3-D air quality models to efficiently solve particle-phase diffusion when particles are viscous. Sensitivity simulations using two organic aerosol models implemented in Polyphemus to represent mass transfer between gas and particle phases show that the computation of the absorbing aerosol mass strongly influences the SOA formation. In particular, taking into account the concentrations of inorganic aerosols and hydrophilic organic aerosols in the absorbing mass of the aqueous phase increases the average SOA concentration by 5% and 6 %, respectively. However, inorganic aerosols influence the SOA formation not only because they constitute an absorbing mass for hydrophilic SOA, but also because they interact with organic compounds. Non-ideality (short-, medium- and long-range interactions) was found to influence SOA concentrations by about 30 %. Concerning the dynamic mass transfer for the SOA formation, if the viscosity of SOA is not taken into account and if ideality of aerosols is assumed, the dynamic approach is found to give generally similar results to the equilibrium approach (indicating that equilibrium is an efficient hypothesis for inviscid and ideal aerosols). However, when a non-ideal aerosol is assumed, taking into account the dynamic mass transfer leads to a decrease of concentrations of the hydrophilic compounds (compared to equilibrium). This decrease is due to differences in the values of activity coefficients, which are different between values computed for bulk aerosols and those for each size section. This result indicates the importance of non-ideality on the dynamic evolution of SOA. For viscous aerosols, assuming a highly viscous organic phase leads to an increase in SOA concentrations during daytime (by preventing the evaporation of the most volatile organic compounds). The partitioning of nonvolatile compounds is not affected by viscosity, but the aging of more volatile compounds (that leads to the formation of the less volatile compounds) slows down as the evaporation of those compounds is stopped due to the viscosity of the particle. These results imply that aerosol concentrations may deviate significantly from equilibrium as the gas-particle partitioning could be higher than predicted by equilibrium. Furthermore, although a compound evaporates in the simulation using the equilibrium approach, the same compound can condense in the simulation using the dynamic approach if the particles are viscous. The results of this study emphasize the need for 3-D air quality models to take into account the effect of non-ideality on SOA formation and the effect of aerosol viscosity for the more volatile fraction of semi-volatile organic compounds