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Actualisation des valeurs guides de qualité d’air intérieur - Benzène (CAS n°71-43-2)
No full textCitation suggérée : Anses. (2024). Actualisation des valeurs guides de qualité de l’air intérieur pour le benzène. (saisine 2021-MPEX-0006). Maisons-Alfort : Anses, 260 p.En France, comme pour l’air extérieur, la qualité de l’air à l’intérieur des bâtiments constitue une préoccupation de santé publique, en particulier puisque chaque individu passe en moyenne, en climat tempéré, 85 % de son temps dans des environnements clos dont une majorité de ce temps dans l’habitat. L’environnement intérieur offre une grande diversité de situations de pollutions par de nombreux agents physiques et contaminants chimiques ou microbiologiques, liées notamment à la nature des matériaux de construction, aux équipements, à l’environnement extérieur immédiat et aux activités des occupants. Or, les pollutions peuvent avoir des conséquences importantes sur l’état de santé des individus, même si elles ne sont pas toutes quantifiables avec précision et s’il est souvent difficile de s’accorder sur la part des déterminants génétiques, sociaux et environnementaux dans l’apparition et le développement des pathologies observées : irritations, maladies allergiques, pathologies dermatologiques d’origine immunitaire, affections broncho-pulmonaires, intoxications aiguës, cancers, syndrome des bâtiments malsains (SBM ou sick building syndrome (SBS)), etc.Les données collectées par l’Observatoire de la Qualité de l’Air Intérieur (OQAI), mis en place par les pouvoirs publics en 2001, ont confirmé la nécessité de disposer, au niveau national et par polluant, de valeurs de référence permettant de situer les niveaux de concentrations mesurées dans les environnements clos et d’instaurer des mesures de réduction des émissions proportionnées notamment au risque potentiel encouru. Par ailleurs, le manque de niveaux de référence pour la qualité de l’air intérieur limite le développement de référentiels utiles pour la qualification, en termes sanitaires, des émissions de composés par les produits de construction, de décoration ou de consommation. Ces éléments manquent également pour la conception de protocoles en vue de la spécification de bâtiments à Haute Qualité Environnementale (HQE).À l’échelle internationale, des valeurs de recommandations sont proposées dans certains pays et par quelques organismes reconnus. Le rapport du projet européen INDEX (CE 2005), financé par la Direction Générale de la Commission Européenne pour la santé et la protection des consommateurs (DG SANCO), a dressé en 2005 une liste de polluants chimiques prioritaires des environnements intérieurs susceptibles d’être réglementés dans le futur et a proposé des valeurs guides de qualité d’air intérieur. Par ailleurs, l’Organisation Mondiale de la Santé (OMS) s’est engagée en 2006 à proposer des valeurs guides de qualité de l’air intérieur (OMS 2006) en distinguant trois groupes : substances chimiques, agents biologiques et polluants émis par la combustion intérieure. Les travaux relatifs spécifiquement à l’humidité et aux moisissures ont été publiés en 2009 (OMS 2009). Puis, des valeurs guides de qualité d’air intérieur ont été publiées fin 2010 pour neuf substances chimiques (OMS 2010). En France, des actions à court, moyen et long terme afin d’améliorer la qualité de l’air dans les espaces clos sont proposées dans les différentes éditions des Plans nationaux Santé environnement (PNSE). Pour faire face à l’enjeu sanitaire que représente la qualité de l’air intérieur et apporter aux pouvoirs publics des éléments utiles à la gestion de ce risque, l’Agence nationale de sécurité sanitaire de l’alimentation de l’environnement et du travail (Anses) s’est autosaisie en 2004 afin d’élaborer des valeurs guides de qualité d’air intérieur (VGAI), fondées sur des critères sanitaires.Les VGAI proposées par l’Anses constituent le socle initial du processus institutionnel visant à fixer des valeurs réglementaires de surveillance de la qualité de l’air intérieur.Afin d’appuyer les pouvoirs publics dans l’élaboration de valeurs opérationnelles permettant de mettre en place des actions d’amélioration de la qualité de l’air intérieur, le ministère chargé de la santé sollicite usuellement le Haut conseil de la santé publique (HCSP) en vue de proposer, à partir des VGAI de l’Anses, des valeurs repères d’aide à la gestion dans l’air des espaces clos, ainsi qu’un calendrier pour leur déploiement. Le HCSP tient compte, dans ses propositions, de considérations pratiques, réglementaires, juridiques, économiques et sociologiques.Enfin, conformément à la loi du 1er août 2008 relative à la responsabilité environnementale, des VGAI réglementaires sont établies par le ministère chargé de l’écologie, inscrites dans lecode de l’environnement et sont associées à des mesures de gestion
Anthropogenic legacy of potassium-40 in French large rivers reconstructed from sediment cores
No full text(IF 8.2; Q1)International audienceEnvironmental imprint of inorganic fertilizer uses was assessed over the last hundred years at the downstream part of large French rivers (Loire, Moselle, Rhine, Rhone, Meuse and Seine rivers) based on Potassium-40 (40K) activity concentration data sets acquired from soil monitoring (1980–2022) and from sediment coes collected from 2020 to 2022 to reconstruct the temporal trajectories of 40K activity concentrations since the beginning of the last century. Cultivated soils were significantly enriched in 40K compared to non-cultivated ones in the 1980s and 1990s when they turned back to the contents of non-cultivated soils during the following decades. In riverine sediments, all the rivers displayed close 40K temporal trajectories with peaking 40K contents in fine grain size sediments in the 1980s. Maximum 40K enrichment factors from this period were related to the proportion of agricultural areas in the river catchment. In the Loire and Moselle rivers, some high 40K contents were associated with sandy sedimentary strata deposited by flood events before the end of the 1950s due to the presence of potassium enriched minerals. The comparison of 40K activity concentration in sediments with potassic fertilizer delivery in France highlighted very similar temporal trajectories giving evidence that the uses of potassic fertilizers imprint the riverine sediments of most French large rivers. Finally, the environmental resilience face to this anthropic pressure was fast as 40K levels decreased immediately after the decreases of the delivery in most of cases
Large-eddy simulation of a full-scale glove box fire
No full textInternational audienceReactive large-eddy simulations (LES) of the stage of peak heat release rate of open atmosphere glove box fires are carried out. To the best of the authors’ knowledge, this is the first time that the LES of such a geometry is reported in the literature. A multi-fuel extension of the eddy-dissipation model (EDM) is used to simulate the combustion of the two distinct solid fuels, PMMA and Polycarbonate, relevant to this configuration. Three increasingly refined grids are considered. All of them lead to temperature values that are in good agreement with experimental data, and similar levels of heat release are obtained inside the glove box. From a more quantitative point of view, only the most refined grid leads to satisfactory values of LES quality criteria. The intermediate grid allows resolving a fraction of the inertial range dynamics, while the solution obtained on the coarsest grid exhibits very large turbulent structures with characteristic sizes of the order of the integral length scale. The analysis confirms that the choice of the grid cell size has a significant influence on the description of the local flow hydrodynamics, the location and thickness of the reactive zones
Combining PIXE and EBS for the analysis of paint layers: Experiment and simulation highlight the influence of the pigment grain size
No full textInternational audiencePIXE and EBS were used simultaneously to characterize paint layers containing pigments of controlled grain size. The experiments were carried out using the external 3 MeV proton beam from the NewAGLAE facility. The paint layers consisted of lead silicate pigments mixed in linseed oil. The pigments were characterized by XRD and SEM prior to IBA measurements. Irregularly shaped grains ranging from 13 to 64 µm were observed.The PIXE spectra were fitted by TRAUPIXE and the EBS spectra were simulated with STRUCTNRA using simplified models of the paint structure assuming non-overlapping spherical pigment particles in oil. For each simulation, the particle size was used as provided by the SEM observations. The density of each paint layer was calculated according to the pigment composition determined by PIXE. For the linseed oil matrix, the oxygen content was fitted at about two times higher than in linseed oil, which is qualitatively consistent with the oxygen uptake during the drying process. The pigment volume fraction and the stick-out fraction were adjusted to fit the experimental spectra. A reasonable agreement between experimental and simulated spectra was achieved. This demonstrates that the simulation and quantitative understanding of EBS spectra from paintings requires the microstructure of the paint layer to be taken into account
Challenges To Develop and Draw Relevant Lessons From A Level 1 Internal Flooding PSA
No full textInternational audienceIn the framework of the 4th Periodic Safety Review (PSR) of the 1,300 MWe French Pressurized Water Reactor (PWR) series, in the streamline with previous PSR, Electricity of France (EDF) has developed a large span of Probabilistic Safety Analysis (PSAs) that cover Internal initiating Events (IE), but also internal hazards (fire, flooding, explosion) and external hazards (seismic, flooding, heat wave and high winds). To support its review of the EDF PSA, IRSN (as Technical Support Organization (TSO) of the French Nuclear Safety Authority (ASN)) has also developed in-house internal initiating events and limited scope hazard PSA. When performing hazard PSA, attention must be paid on the hazard characterization (magnitude/frequency), identification of the most important scenarios and assessment of the hazard impact on the plant and on the conditions to perform emergency human actions to mitigate the accident. Generally, the PSA assumptions are best estimate and may be different from the deterministic study conservative assumptions. As hazard PSAs cover many complex scenarios, it is a challenge to develop a complete set of representative supporting studies and to evaluate all hazard impacts on the plant and the human factors. In addition, the hazard characterization is challenging because representative data and operating experience are rare. Therefore, the interpretation of hazard PSA results, risk ranking, and safety insights must rely on an acute analysis of the PSA limits. This paper focuses on the recent lessons learned from the Level 1 internal flooding PSA developed or reviewed by IRSN
An experimental study of the thermal-hydraulics of a spent nuclear fuel pool under loss-of-cooling accident conditions. Part I: The MIDI facility and its main experimental results
No full textInternational audienceMotivated by the 2011 accident at the Fukushima Daiichi nuclear power station, the French Institute for Radiation Protection and Nuclear Safety (IRSN) launched in 2014 the DENOPI project. This research program, supported by the French Government and carried out in collaboration with national and international partners, dealt with the open issues of spent fuel pool accidents. As part of this project, a test facility named MIDI was designed and built at the IRSN’s research unit of Cadarache, France. The MIDI facility is an experimental tool which aims at reproducing the thermal–hydraulic phenomena that may occur at an integral scale in a spent fuel pool undergoing a loss-of-cooling accident, before the stored fuels get uncovered. This paper first describes the MIDI facility and its instrumentation and the test matrix achieved to date. An overview of its main results is then provided. In the framework of the DENOPI project, nine tests were achieved and allowed investigating the phenomenology of this type of accident. The highlighted phenomenology is characterized by three competing liquid vaporization modes: the evaporation at the pool free surface, the nucleate boiling within the fuel bundles and the gravity-driven flashing of superheated water on top of the storage racks. The existence of the latter vaporization mode, uncertain at the launch of the DENOPI project, is now confirmed in the configuration of a spent fuel pool
Anoxic corrosion of carbon steel in high pH cementitious media and high temperature conditions: New insights on the formation of (Fe,Al)Si-hydrogarnet corrosion product
No full textInternational audienceThe corrosion of carbon steel in alkaline anaerobic conditions and high temperature (80◦C) was studied through mock-up tests representative of imperfect contact between steel and cementitious material. The evolution of the whole system, including cement mineralogy, reservoir solution chemistry, corrosion product and rate, was fol- lowed over one year. SEM-EDX and XRD analyses indicated that the corrosion product layer was mostly constituted of (Fe,Al)Si-Hydrogarnet ((Fe,Al)Si-HG) and that its densification progressively inhibited corrosion. Thermodynamic and reactive transport modelling helped to better constrain the chemical and temperature conditions of (Fe,Al)Si-HG formation
Biogeochemical recycling of K and Cs isotopes in deciduous forest stands on the long term after deposition
No full textInternational audienceDue to atmospheric releases from the Chernobyl and Fukushima accidents, Cs-137 long half-live (30y) and its incorporation into the biogeochemical cycle of elements lead to its persistence within forest ecosystems, affecting forest ecosystem services even more since their decontamination is hardly possible. Predicting its behavior and transfer dynamics over time is of key importance to help recovering benefit from forest products. Such assessment studies require the transfer processes to be documented with numerous data to encompass the variability of environmental factors (e.g. species, age, climate, deposit). To date, the root-uptake which is known to be the major process of Cs-137 intake in trees after the transition phase (>10y) couldn’t be robustly assessed due to the remaining contribution of initial foliar uptake. More, data remain scarce for deciduous trees as most post-Chernobyl and post-Fukushima field studies mainly focused on evergreen species.Relying on stands monitoring data collected during the post-accident long-term phase (>30y) in 4 various deciduous forest stands (France, Ukraine), we compared their Cs-137 concentrations and inventories distributions in trees as well as those of stable chemical analogues (Cs-133, K). To differentiate annual root-uptake from internal translocations fluxes in trees, we assessed their biogeochemical cycling fluxes (mass balance approach).On the long-term, the Cs-137 initial foliar uptake contribution was no more visible at our sites due to biomass dilution and Tag (aggregated transfer factor) values were one order of magnitude lower than reference ones (IAEA, 2009) likely indicating a long-term decrease of Cs-137 bioavailability in soil. The concentrations of Cs-133 and Cs-137 normalized by the exchangeable inventories in soil were linearly correlated (r>0.7, p<0.05) and differences between isotopes were explained by the soil depth root density. The Cs isotopes were more sequestered than K in roots. Compared to evergreen coniferous forests, uptake rates (y-1) were up to twice higher for K but up to 10 times lower for Cs isotopes, consequently exhibiting a stronger Cs/K discrimination. In a Q. serrata stand sampled in 2014-2018 (Japan, early-medium stage) where dynamics were slower than for coniferous, use of Cs-133 and K to assess the magnitude of Cs-137 root uptake rate is underway.2 376 / 5 000En raison des rejets atmosphériques des accidents de Tchernobyl et de Fukushima, la longue demi-vie (30 ans) du Cs-137 et son incorporation dans le cycle biogéochimique des éléments conduisent à sa persistance au sein des écosystèmes forestiers, affectant d'autant plus les services écosystémiques forestiers puisque leur décontamination est difficilement possible. . Prédire son comportement et sa dynamique de transfert dans le temps est d’une importance capitale pour aider à récupérer les bénéfices des produits forestiers. De telles études d'évaluation nécessitent que les processus de transfert soient documentés avec de nombreuses données pour englober la variabilité des facteurs environnementaux (par exemple, espèces, âge, climat, gisement). À ce jour, l’absorption racinaire, connue pour être le processus majeur d’absorption du Cs-137 dans les arbres après la phase de transition (> 10 ans), n’a pas pu être évaluée de manière robuste en raison de la contribution restante de l’absorption foliaire initiale. De plus, les données restent rares pour les arbres à feuilles caduques, car la plupart des études de terrain post-Tchernobyl et post-Fukushima se sont principalement concentrées sur les espèces à feuilles persistantes.En nous appuyant sur les données de suivi des peuplements collectées pendant la phase post-accidentelle à long terme (>30 ans) dans 4 peuplements forestiers feuillus différents (France, Ukraine), nous avons comparé leurs concentrations et répartitions des stocks de Cs-137 dans les arbres ainsi que celles des composés chimiques stables. analogues (Cs-133, K). Pour différencier l'absorption racinaire annuelle des flux de translocations internes dans les arbres, nous avons évalué leurs flux de cycles biogéochimiques (approche bilan de masse).À long terme, la contribution initiale de l'absorption foliaire du Cs-137 n'était plus visible sur nos sites en raison de la dilution de la biomasse et les valeurs du Tag (facteur de transfert agrégé) étaient d'un ordre de grandeur inférieures à celles du Cs-137. ceux de référence (AIEA, 2009) indiquant probablement une diminution à long terme de la biodisponibilité du Cs-137 dans le sol. Les concentrations de Cs-133 et de Cs-137 normalisées par les inventaires échangeables dans le sol étaient linéairement corrélées (r>0,7, p<0,05) et les différences entre les isotopes étaient expliquées par la densité des racines en profondeur du sol. Les isotopes Cs étaient plus séquestrés que K dans les racines. Comparés aux forêts de conifères à feuilles persistantes, les taux d'absorption (y-1) étaient jusqu'à deux fois plus élevés pour le K mais jusqu'à 10 fois plus faibles pour les isotopes du Cs, présentant par conséquent une discrimination Cs/K plus forte. Dans un peuplement de Q. serrata échantillonné en 2014-2018 (Japon, stade précoce-moyen) où la dynamique était plus lente que celle des conifères, l'utilisation du Cs-133 et du K pour évaluer l'ampleur du taux d'absorption racinaire du Cs-137 est en cours
Fundamentals of wildlife dosimetry and lessons learned from a decade of measuring external dose rates in the field
No full textInternational audienceMethods for determining the radiation dose received by exposed biota require major improvements to reduceuncertainties and increase precision. We share our experiences in attempting to quantify external dose rates tofree-ranging wildlife using GPS-coupled dosimetry methods. The manuscript is a primer on fundamental conceptsin wildlife dosimetry in which the complexities of quantifying dose rates are highlighted, and lessons learned arepresented based on research with wild boar and snakes at Fukushima, wolves at Chornobyl, and reindeer inNorway. GPS-coupled dosimeters produced empirical data to which numerical simulations of external dose usingcomputer software were compared. Our data did not support a standing paradigm in risk analyses: Usingaveraged soil contaminant levels to model external dose rates conservatively overestimate the dose to individualswithin a population. Following this paradigm will likely lead to misguided recommendations for risk management.The GPS-dosimetry data also demonstrated the critical importance of how modeled external dose rates areimpacted by the scale at which contaminants are mapped. When contaminant mapping scales are coarse evendetailed knowledge about each animal’s home range was inadequate to accurately predict external dose rates.Importantly, modeled external dose rates based on a single measurement at a trap site did not correlate to actualdose rates measured on free ranging animals. These findings provide empirical data to support published concernsabout inadequate dosimetry in much of the published Chernobyl and Fukushima dose-effects research. Ourdata indicate that a huge portion of that literature should be challenged, and that improper dosimetry remains asignificant source of controversy in radiation dose-effect research
Uranium contamination of bivalve Mytilus galloprovincialis, speciation and localization
No full textInternational audienceUranium is a natural radioelement (also a model for heavier actinides), but may be released through anthropogenicactivities. In order to assess its environmental impact in a given ecosystem, such as the marine system, itis essential to understand its distribution and speciation, and also to quantify its bioaccumulation. Our objectivewas to improve our understanding of the transfer and accumulation of uranium in marine biota with musselstaken here as sentinel species because of their sedentary nature and ability to filter seawater.We report here on the investigation of uranium accumulation, speciation, and localization in Mytilus galloprovincialisusing a combination of several analytical (Inductively Coupled Plasma Mass Spectrometry, ICP-MS),spectroscopic (X ray Absorption Spectroscopy, XAS, Time Resolved Laser Induced Fluorescence Spectroscopy,TRLIFS), and imaging (Transmission Electron Microscopy, TEM, μ-XAS, Secondary Ion Mass Spectrometry, SIMS)techniques. Two cohorts of mussels from the Toulon Naval Base and the Villefranche-sur-Mer location werestudied. The measurement of uranium Concentration Factor (CF) values show a clear trend in the organs ofM. galloprovincialis: hepatopancreas ≫ gill > body ≥ mantle > foot. Although CF values for the entire mussel arecomparable for TNB and VFM, hepatopancreas values show a significant increase in those from Toulon versusVillefranche-sur-Mer.Two organs of interest were selected for further spectroscopic investigations: the byssus and the hepatopancreas.In both cases, U(VI) (uranyl) is accumulated in a diffuse pattern, most probably linked to protein complexingfunctions, with the absence of a condensed phase.While such speciation studies on marine organisms can be challenging, they are an essential step for decipheringthe impact of metallic radionuclides on the marine biota in the case of accidental release. Following ourassumptions on uranyl speciation in both byssus and hepatopancreas, further steps will include the inventory andidentification of the proteins or metabolites involved