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Evaluation of Placental Transfer and Tissue Distribution of cis- and Trans-Permethrin in Pregnant Rats and Fetuses Using a Physiological-Based Pharmacokinetic Model
No full textInternational audienceBiomonitoring studies have highlighted the exposure of pregnant women to pyrethroids based on the measurement of their metabolites in urine. Pyrethroids can cross the placental barrier and be distributed in the fetus as some pyrethroids were also measured in the meconium of newborns. Prenatal exposure to pyrethroids is suspected to alter the neurodevelopment of children, and animal studies have shown that early life exposure to permethrin, one of the most commonly used pyrethroid in household applications, can alter the brain development. This study aimed to characterize the fetal permethrin exposure throughout gestation in rats. We developed a pregnancy physiologically based pharmacokinetic (pPBPK) model that describes the maternal and fetal kinetics of the cis - and trans - isomers of permethrin during the whole gestation period. Pregnant Sprague–Dawley rats were exposed daily to permethrin (50 mg/kg) by oral route from the start of gestation to day 20. Permethrin isomers were quantified in the feces, kidney, mammary gland, fat, and placenta in dams and in both maternal and fetal blood, brain, and liver. Cis - and trans -permethrin were quantified in fetal blood and tissues, with higher concentrations for the cis -isomer. The pPBPK model was fitted to the toxicokinetic maternal and fetal data in a Bayesian framework. Several parameters were adjusted, such as hepatic clearances, partition coefficients, and intestinal absorption. Our work allowed to estimate the prenatal exposure to permethrin in rats, especially in the fetal brain, and to quantitatively estimate the placental transfer. These transfers could be extrapolated to humans and be incorporated in a human pPBPK model to estimate the fetal exposure to permethrin from biomonitoring data
Operationalizing the Health-Environment Nexus: Measuring Environmental Health Inequalities to Inform Policy
No full textInternational audienceThe identification of vulnerable individuals and communities at risk in order to target public health interventions relies on environmental health inequality indicators based on exposure assessment processes. The indicator framework should be able to investigate the processes taking place at the interface between the environment and the populations, and to characterize the principal environmental impact factors. The goal of this chapter is to contribute to the development of policy-relevant environmental health inequality indicators. I first present the scientific contexts in which the characterization of Environmental Health Inequalities operates and the need for indicators to inform decision-making. Examples of existing indicators are then briefly examined to present concise measurement frameworks and issues in data processing. Finally, I offer some recommendations as to the type of indicators needed and their possible integration in public policies
Automatic generation from MCM of reduced mechanisms to study the formation and evolution of SOA in 3D air quality models
No full textInternational audienceAs secondary organic aerosols (SOA) largely contribute to the mass of particles and may strongly affect health, it is essential to represent them as accurately as possible in air quality models (AQM). Their formation and aging involve multi-generation oxidations of numerous volatile organic compounds (VOC) combined with gas-particle partitioning processes.Tracking the non-linear relationship between VOC emissions and aerosol formation demands comprehensive chemical mechanisms, which take into account the whole complexity of the SOA precursor oxidation to simulate aerosols under various conditions.However, the use of explicit gas-phase chemical mechanism (e.g., MCM, GECKO-A) or molecular structure-limited parameterization (e.g., VBS, SOM, FGOM) could be problematical in large-scale SOA modeling, as the former is overwhelmingly computational expensive while the latter loses tracks of VOC oxidation products after few generations and specific properties relying on aerosol formation.Consequently, we have developed semi-explicit SOA chemical mechanisms designed to model the SOA formation and evolution in 3D AQM. These mechanisms are reduced based on simulations of the near-explicit master chemical mechanism (MCM) performed under various conditions representative of ambient conditions and different lumping strategies. The new mechanisms integrate the crucial SOA species/reactions with different mechanism complexities. The mechanisms, therefore, preserve the complexity of the oxidation chemistry (dependence on NOx of the SOA formation, the influence of radical concentrations, humidity, photolysis, etc..) as well as the molecular composition of the organic aerosol. The mechanisms are implemented in a novel 0D aerosol model SSH-aerosol, which can use the molecular structure of lumped compounds to estimate the influence of non-ideality on SOA formation.The current application has been conducted on the MCM degradation scheme of beta-caryophyllene (C<sub>15</sub>H<sub>24</sub>), the most representative sesquiterpene. A reduction of the average 90% CPU time and up to 92% number of S/IVOCs species has been achieved compared to the original MCM mechanism
First year of real-time VOC measurements at the SIRTA facility (Paris region, France): diurnal and seasonal variabilities, impact of lockdowns on air quality
No full textInternational audienceVolatile Organic Compounds (VOCs) have direct influences on air quality and climate. They also play a key role in atmospheric chemistry, as they are precursors of secondary pollutants, such as ozone (O<sub>3</sub>) and secondary organic aerosols (SOA).Long-term datasets of in-situ atmospheric measurements are crucial to characterize the variability of atmospheric chemical composition. Online and continuous measurements of O<sub>3</sub>, NO<sub>x</sub> and aerosols have been achieved at the SIRTA-ACTRIS facility (Paris region, France), since 2012. Regarding VOCs, they have been measured there for several years thanks to bi-weekly samplings followed by offline Gas Chromatography analysis. However, this method doesn&#8217;t provide a good representation of the temporal variability of VOC concentrations. To tackle this issue, online VOC measurements using a Proton-Transfer-Reaction Quadrupole Mass-Spectrometer (PTR-Q-MS) have been started in January 2020.The dataset acquired during the first year of online VOC measurements is analyzed, which gives insights on VOC seasonal variability. The additional long-term datasets obtained from co-located measurements (O<sub>3</sub>, NO<sub>x</sub>, aerosol physical and chemical properties, meteorological parameters) are also used for the sake of this study.Due to Covid-19 pandemic, the year 2020 notably comprised a total lockdown in France in Spring, and a lighter one in Autumn. Therefore, a focus can be made on the impact of these lockdowns on the VOC variability and sources. To this end, the diurnal cycles of VOCs considered markers for anthropogenic sources are carefully investigated. Results notably indicate that markers for traffic and wood burning sources behave quite differently during the Spring lockdown in comparison to the other periods. A source apportionment analysis using positive matrix factorization allows to further document the seasonal variability of VOC sources and the impacts on air quality associated with the lockdown measures
Automatic Detection and Location of Microseismic Events from Sparse Network and Its Application to Post-mining Monitoring
No full textInternational audienceIn post-mining regions with seismic hazard, timely decision making for risk management faces the challenge of quick and reliable detection and location of seismic events. As a response to the increasing density of monitoring stations, generating large volumes of seismic data, automatic, full waveform-based methods have been developed in recent years in global seismology. Such methods often cannot be directly applied to post-mining monitoring with a limited station coverage, as it is the case when temporarily networks are installed as an emergency response. In this paper we propose a new methodology that bridges this gap and enables the application of a full waveform, backprojection based method (BackTrackBB) to data of sparse network. The methodology was successfully tested on an abandoned and flooded underground coalmine in South-eastern France. Steps preceding BackTrackBB application were implemented in order to remove the coherent noise that otherwise results in numerous false detections. First results indicate that seismic activity in the study area is controlled by water level variation within former room-and-pillar mine works and fault segments (re)activation below them
Diagnostiquer et réduire à la source les micropolluants -Retour d'expérience du projet Regard (Bordeaux Métropole)
No full textMicropollutants (MPs) represent an important environmental and health issue. Identifying their sources and then reducing their discharges is the strategy used in France to fight against water pollution. This is also the approach implemented in the Regard project (Reduction and management of micropollutants in the Bordeaux metropolis). The first phase of the project aimed to carry out a territorial, global and integrated diagnosis combining both chemical and biological analyses of the natural environment and the sewerage network from the discharge points (wastewater treatment plant, separate stormwater overflow, by-pass) to the emission sources (domestic, industrial, hospital and stormwater). In addition, a social characterization of the sources was carried out in order to understand the practices, products and uses at the origin of MP discharges and to identify decisive actions to reduce these discharges. The strengths of this diagnostic assessment are the complementary of various approaches (engineering and social sciences, chemical and biological analyses, wastewater and stormwater studies) and the large number of sampling sites. The second phase of the project was to ensure the implementation of reduction actions to test and evaluate their impacts from the environmental (effectiveness in reducing the quantity, diversity and effect of MPs), social (appropriation and satisfaction of solutions) and economic (to guide public action) points of view. The best results have been achieved with (i) the “water families challenge” action on the domestic source, (ii) mechanical rat control actions, defoaming of tennis courts and grassing of cemeteries for the community source, and (iii) the treatment action of separate stormwater in real conditions on a pilot scale. This feedback on what has been achieved to date should help communities interested to implement such an approach in order to avoid the same “mistakes” and, on the contrary, to directly implement actions that give significant reduction results.Les micropolluants (MP) représentent un enjeu environnemental et sanitaire important. Identifier leurs sources pour ensuite réduire leurs rejets est la stratégie privilégiée au niveau français pour lutter contre cette pollution. C’est aussi la démarche qui a été mise en oeuvre dans le projet Regard (réduction et gestion des micropolluants sur la métropole bordelaise). La première phase du projet correspondait ainsi à la réalisation d’un diagnostic territorial, global et intégré couplant à la fois des analyses chimiques et biologiques du milieu naturel et du réseau d’assainissement depuis les points de rejets (station de traitement des eaux usées, exutoires pluviaux, by-pass) jusqu’aux sources d’émission (domestique, industrielle, hospitalière et pluviale). En complément, une caractérisation sociale dessources a été faite afin de comprendre les pratiques, les produits et les usages à l’origine des rejets de MP et d’identifier des leviers d’action pour réduire ces rejets. Les points forts de ce diagnostic sont la complémentarité des approches (sciences de l’ingénieur et sciences sociales, analyses chimiques et biologiques, étude des eaux usées et pluviales) et le nombre important de sites d’étude. La seconde phase du projet correspondait à la mise en oeuvre d’actions de réduction pour les tester et les évaluer du point de vue environnemental (efficacité pour réduire la quantité, la diversité et l’effet des MP), social (appropriation et satisfaction vis-à-vis des solutions) et économique (aide à l’orientation de l’action publique). Les actions ayant eu les meilleurs résultats sont (i) l’action « Familles EAU Défi » sur la source domestique, (ii) les actions de dératisation mécanique, de démoussage des terrains de tennis et d’enherbement des cimetières pour la source collectivité et (iii) l’action de traitement des eaux pluviales strictes en conditions réelles à l’échelle d’un pilote. Le présent retour d’expérience sur ce qui a été fait doit aider les collectivités qui souhaiteraient effectuer une telle démarche à ne pas commettre les mêmes « erreurs » et, au contraire, à mettre en oeuvre directement les actions qui donnent des résultats satisfaisants
Development of an Untargeted Metabolomics Approach Based on LC-(ESI)-HRMS, Applied to Three-Spined Sticklebacks Exposed to Diclofenac
No full textInternational audienceIntroduction The aquatic systems are the ultimate repository of a large part of the compounds due to human activities. In response to these chemical stresses which aquatic environment may suffer, most studies have focused on the use of biomarkers as early responses induced by these pressures. In recent years, several studies showed that metabolomics can be used to compare and determine the causal link between exposure and effects for predicting toxic effects of contaminants in aquatic organisms. Especially, untargeted approaches based on high resolution mass spectrometry has gained more and more popularity due to its benefit of analysing the whole metabolome in a global view. This approach is a promising tool to provide biomarkers of effect and information on exposure ways in organisms in view of aquatic biomonitoring and environmental risk assessment. The aims of this study were : - To develop an exhaustive untargeted approach able to cover a huge range of metabolites within three-spined sticklebacks (Gasterosteus aculeatus) - To identify impacted metabolites after a sub-chronic exposure of this species to diclofenac. Materials and methods A solid liquid extraction followed by liquid chromatography (RSLC U3000 from Thermo Scientific®) coupled to QtoF (Maxis Plus from Bruker Daltonics®) were used. The data were processed using Metaboscape 4.0 (Bruker Daltonics®). The extraction process was performed on 25 or 50 mg of whole fish, liver, gills or brain with 2.5 mL of MeOH/H2O/heptane. Two complementary analytical methods were then combined : a reverse phase separation on HSS T3 C18 column for positive ionization mode, and an HILIC separation on Nucleodur column for negative ionization mode. This development was done to identify finer and then more relevant biomarkers by a comparative strategy between control and exposed individuals to diclofenac. Results and discussion Two LC-HRMS methods have been developed based on the responses of analytical standards representative of different metabolite groups (amino acids, sugars...). The extraction protocol has been optimized in all matrices, taking into account the number of features (m/z, tr) observed in LC-HRMS. The study shows the influence of the nature of the solvents during the extraction stage as well as the choice of chromatographic conditions. These methods were applied to adult fish exposed to diclofenac, a non-steroidal anti-inflammatory drug ubiquitous in the environment. Individuals were exposed for 21 days at 1 and 100 µg/L. The results of the untargeted metabolomic approach will be presented during the speech. Conclusions This study provides a complete reliable analytical method for the characterization of metabolites in three-spined sticklebacks. Thus, it enables to identify biomarkers through a comparative strategy, for biomonitoring of water bodies quality
An Imprecise Bayesian Approach to Thermal Runaway Probability
No full textInternational audienceIn this pioneering work, an assessment of thermal runaway probability based on simplified chemical kinetics has been performed with imprecise Bayesian methods relying on several priors. The physical phenomenon is governed by two chemical kinetic parameters A and Ea. We suppose that their values are considerably uncertain but also that we know the experimental profiles of a chemical species corresponding to their true values, thereby allowing us to compute likelihoods and posteriors corresponding to different levels of information. We are interested in the critical delay time tc beyond which an explosion will certainly occur. The use of several priors allows us to see when the data truly dominate the prior with respect to the probability distribution of tc. It does not appear possible to do so in an orthodox precise Bayesian framework that reduces all forms of uncertainty to a single probability distribution
Synthesis of large-scale source apportionment of oxidative potential at 15 sites in France
No full textInternational audienceAtmospheric ambient particulate matter (PM) is linked to diverse health outcomes such as asthma, cardiovascular disease and increased cancer risk. Although PM present a wide span of size, shape, chemical composition and so sanitary impacts, epidemiological studies usually focus on PM mass concentrations only. The oxidative potential (OP) of PM has been proposed as a new proxy for air quality in order to better estimate the population exposure since it integrates the different PM characteristic and is closely linked to the inflammatory response of the body to the oxidative stress induced by PM. However, long time-series of OP measurement are still limited in the literature and no standardized assays has emerged. Moreover, very few source apportionment studies of OP have been conducted yet
Real-time source apportionment of organic aerosols in three European cities
No full textInternational audienceAtmospheric particulate matter (PM) has direct and indirect effects on public health, ecosystems and climate (IPCC, 2014). At the same time, European countries are still suffering from poor air quality: 70% of air quality monitoring stations within Europe exceed the annual PM2.5 value of the WHO guidelines (10 μg/m3) (European Environment Agency (EEA), 2020). Considering organic aerosol (OA) is one of the major components of PM (Jimenez et al., 2009), the knowledge of OA sources is extremely valuable for policymakers in order to design effective mitigation strategies