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Pertinence d'une approche multibiomarqueurs en biosurveillance active avec l'épinoche à trois épines (Gasterosteus aculeatus)
No full textMany chemical contaminants have been produced and spread into aquatic environments and given rise to anthropogenic activities. In order to assess and predict the impacts of this contamination on organisms and ecosystems, several tools were developed. Among them, biomarkers have been shown to be sensible and early indicators of a perturbation at sub individual level. These physiological responses can be measured in native individuals as well as in individuals from husbandry imported on the field through caging systems. This latter approach, mostly known as active biomonitoring approach, brings with it the ability to overcome some confounding factors present when native individuals are used (history, exposure time, adaptation mechanism). Additionally, the use of imported individuals enables the study of sites in which the model species is endangered or absent. This active methodology also seems more effective in defining reference levels for the comparison of sites over large geographic scales. In this context, the present work aims to assess the relevance of using a new model species in active biomonitoring approach: the three spined stickleback (Gasterosteus aculeatus). Several physiological functions have been chosen to be representative of the global health of individuals (antioxidant system and oxidative damages, biotransformation enzymes, reproduction system, innate immune system, synaptic transmission). As a first step, the effect of a restricted access to food and the confinement induced by caging conditions have been characterized in two seasons with the aim to ensure a correct and thorough interpretation of the results. Then, the approach has been deployed on the field (i) to assess the efficiency of a constructed wetland built downstream a wastewater treatment plant (WWTP), (ii) to assess the potential effects of several effluents of WWTP and (ii) to discriminate different sites along the Meuse basin (Interreg DIADeM program). Findings have been encouraging in highlighting the relevance of the three spined stickleback as a sentinel species and the selected biomarkers in this context of contamination in active biomonitoring. In a larger scale, these same tools have made it possible to discriminate the different sites in the Meuse basin according to the modulated physiological functions. Thus, this work has demonstrated the potential of the multibiomarker approach in active biomonitoring with the three spined stickleback in the assessment and the characterization of water quality.Le développement des activités anthropiques a engendré la production et la diffusion de nombreux contaminants chimiques dans les milieux aquatiques. Afin d’évaluer l’état des masses d’eau et de prédire les impacts de cette contamination générale sur les organismes vivants et sur les écosystèmes, différents outils ont été développés. Parmi ces outils, les biomarqueurs présentent un intérêt particulier, lié à leur grande sensibilité et leur précocité de réponse. Ils peuvent être utilisés sur des organismes autochtones prélevés directement dans les milieux d’intérêt, ou sur des individus issus du laboratoire et importés sur les sites d’études via des dispositifs d’encagement. Cette seconde approche, dite de biosurveillance active, permet de s’affranchir d’un certain nombre de biais liés aux incertitudes concernant les individus sauvages (historique, temps d’exposition, adaptation) et permet également l’évaluation de sites sur lesquels l’espèce modèle est absente ou menacée. Cette méthodologie active semble également plus appropriée pour définir un référentiel visant à la comparaison de sites sur une échelle géographique importante. Dans ce contexte, le travail réalisé a pour objectif d’évaluer la pertinence de l’utilisation en biosurveillance active d’une espèce modèle bien documentée en écologie : l’épinoche à trois épines (Gasterosteus aculeatus). Les réponses biologiques étudiées portent sur plusieurs fonctions physiologiques (système antioxydant et dommages oxydatifs, enzymes de biotransformation, système reproducteur, transmission synaptique et système immunitaire inné) afin d’être représentatives de l’état de santé global des individus. Dans un premier temps, les effets du confinement ainsi que de la restriction d’accès à la nourriture induits par l’encagement sur la batterie de biomarqueurs ont été caractérisés afin de permettre une interprétation correcte et rigoureuse des résultats. L’approche a ensuite été déployée in situ dans le but (i) d’évaluer l’efficacité d’une zone humide tampon construite en aval d’une station de traitement des eaux usées (STEU), (ii) d’évaluer l’effet potentiel de plusieurs effluents de STEU sur le milieu récepteur et (iii) de discriminer les différents sites le long du bassin de la Meuse (programme Interreg DIADeM). Le déploiement des outils dans ce contexte a mis en évidence la pertinence de l’espèce modèle et des biomarqueurs sélectionnés dans la caractérisation des effets sur les milieux aquatiques de ce type d’installation. A une plus large échelle, les outils ont permis de discriminer les différents sites en fonction des réponses physiologiques modulées. Les travaux ont ainsi mis en évidence tout le potentiel d’une approche multibiomarqueurs en biosurveillance active dans l’évaluation et la caractérisation des milieux aquatiques
Diagnostiquer : inventorier, surveiller et évaluer: inventorier, surveiller et évaluer
No full textInternational audienc
Comprendre le devenir du perfluorooctane sulfonate chez la truite arc-en-ciel (Onchorynchus mykiss) à l'aide d'un modèle toxicocinétique à base physiologique
No full text[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiplesInternational audiencePer- and poly-fluorinated substances (PFAS) are widely found in freshwater ecosystems because of their resistance to degradation. Among them, several long-chain perfluoroalkyl acids bioaccumulate in aquatic vertebrates, but our understanding of the mechanisms of absorption, distribution and elimination is still limited in fish. For this purpose, we developed a 10-compartment physiologically-based toxicokinetic (PBTK) model to elucidate perfluorooctane sulfonate (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 inferences. First, only PFOS absorption by diet was considered in the model as well as its elimination by urine, bile and feces. Then two mechanistic hypotheses, assumed to govern PFOS toxicokinetics in fish, namely the enterohepatic cycle and the absorption and elimination though gills, were tested. Improvement of the model's fit to the data was studied in each organ by comparing predictions with observed data using relative error. The experimental data set was obtained from an exposure experiment, where adult rainbow trout were fed with a PFOS-spiked diet for 42 days, followed by a 35-day depuration period. In all cases, PFOS concentrations were accurately predicted in organs and feces by the model. The results of this PBTK model demonstrated that feces represented the major elimination route for PFOS while urine was a minor route. Also, PFOS branchial uptake can be substantial despite low concentrations of the compound in water, and elimination through gills should not be neglected. Finally, the enterohepatic cycle is likely to play a minor role in PFOS toxicokinetics. Overall, this PBTK model accurately described PFOS distribution in rainbow trout and provides information on the relative contribution of absorption and elimination pathways
L’utilisation future de l’espace souterrain
No full textInternational audienceD’après les Nations Unies, la population urbaine devrait augmenter de 1,5 milliard d’humains d’ici 2030 et atteindre 60% de la population mondiale (Barthélémy, 2012). Des chercheurs ont ainsi prédit par modélisation,un triplement de la superficie de l’espace urbain mondial, à raison d’une augmentation moyenne de 110 km2 par jour (Seto et al., 2012). Pour limiter l’impact environnemental de cette urbanisation de masse, ils ont notamment suggéré, de privilégier la densification des villes plutôt que leur étalement. Cette densification devra se concevoir en hauteur mais également en profondeur avec le développement de l’urbanisme souterrain, ce qui pourrait permettre de résoudre de nombreux problèmes parmi lesquels (Broere, 2016 ; Thewes et al., 2012) : la congestion du trafic et la pollution induite (y compris sonore), la protection contre les risques naturels (crues, pluies,ouragans, neige, gel, séismes…), l’impact environnemental des projets, le manque d’espace en surface (notamment pour des stockages), la récupération d’énergie (géothermie, stockage de chaleur, STEP2 souterraines) ou la protection de grands équipements sensibles (scientifiques, militaires, informatiques…)
Seasonal size distribution and mixing state of black carbon aerosols in a polluted urban environment of the Yangtze River Delta region, China
No full textInternational audienceThe optical properties of black carbon aerosols (BC) are determined by the particles size and the associated non-BC materials, which may be source-related or modified during secondary processing. The one-year long monitoring of BC was first conducted using a Single Particle Soot Photometer (SP2) from December 2013 to November 2014 in Nanjing, a megacity in the Yangtze River Delta region of China. The seasonal variation in the BC size distribution and mixing state were investigated. There was no apparent systematic variation in the mean BC core mass median diameter between seasons, as these values were 226 +/- 12 nm, 217 +/- 13 nm, 211 +/- 15 nm and 221 +/- 12 nm for winter, spring, summer and autumn respectively. The mixing state of BC was quantified as the bulk relative coating thickness (defined as particle size D(p )over core size D-c, D-p/D-c), which ranged from 1.05 to 2.65. The BC was found to be significantly more coated in the winter (D-p/D-c = 1.50 +/- 0.30) than in other seasons (D-p/D-c = 1.27 +/- 0.09, 1.28 +/- 0.10, 1.27 +/- 0.11 in spring, summer and autumn respectively). Higher levels of coating during the winter may due to the contributions of the primary source (with the highest BC mass loadings between seasons) or secondary processes such as low temperature that facilitated the condensation. It was found that the photochemical process may enhance the coatings on BC in summer. At nighttime, the reduced and stabilized planetary boundary layer and the nighttime secondary formation may also lead to BC becoming well mixed with other components. Moreover. BC was shown to be less coated when the NOx concentration was high. However, during all seasons, the BC coating was strongly correlated with other non-BC particulate mass, which suggests that at higher pollution levels BC was more significantly coated with other existing materials through coagulation or condensation by other secondary species
The sorting of waste for a circular economy : sampling when (very) few particles have (very) high concentrations of contaminant or valuable element
No full textInternational audienceThe measurement of elements in numerous individual particles (≥ 1 cm²) by a portable X-ray fluorimeter is used to review a part of the sampling theory of granular solid waste for environmental studies and the circular economy. The paper addresses the case when the concentration of element or substance is not related to the grain size. The key concept (from the binomial law) is the number of particles that must be present in a portion of matter to be representative of a larger portion of matter. This number depends on the frequency of particles having the studied property, and on the desired variability of this property. In all cases, the lowest achievable variability is the analytical variability with the smallest possible test portion (results cannot be less variable). The studied property can either be the presence of an element or a substance, or the presence of an element or a substance at a given concentration. Those concepts are the basis of the existing sampling standards but are not presented as such. As a result, the equations of these standards are not easy to understand and, to our knowledge, rarely used to calculate the mass of a representative sample. When the distributions of concentrations are skewed by (very) large values, the last centiles of concentration tremendously increase the observed mean concentration of a waste heap or flow, and a representative sample must include these last centiles of particles for a proper characterizing and sorting of waste and secondary raw material for the circular economy. Data of centiles of concentrations per particle and laboratory analytical variability are presented. The resulting recommended number of particles that should be present in a sample at any scale from the waste stream (thousands of tons) to the test portion (frequently less than one gram) is estimated at 100 000. Some published sampling plans (from the waste stream to the laboratory sample) and analytical standards (from the laboratory sample to the test portion) are then reviewed for the number of particles. It is crucial to measure the mean mass of the particles to sample, from the granulometric distribution of the particles, and the bulk density, to determine the weight and volume of 100 000 particles. If there is a fine fraction (< 63 μm or even < 1 mm), the recommended mass or volume complies with the requirement of n ≥ 100 000. When there is no fine fraction, like for some WEEE plastic scraps, the volume recommended in technical specification and standard for laboratory sample can’t have enough particles for p = 0.001, but well for p = 0.1 for plastics from small household appliances or higher p for plastics from fluorescent lamps. These p values must be verified for these plastics but are probably not unrealistic for the unsorted fraction. On the other hand, using the equation of the sampling standards overestimates the mean mass of particle when fines are present. Another application is the evaluation of the number of particles to measure individually, in order to calculate the fraction of particles trespassing a given concentration of an element, and the confidence interval of that fraction
Instability mechanisms of chalk mines in presence of water : feedback from the collapse of the Baulieu mine (France)
No full textInternational audienceThe weakening of chalk mechanical characteristics under the influence of ageing and flooding/unflooding cycles may be at the origin of dramatic collapses. For illustration, in January 1910, the collapse of the underground chalk mine known as "Beaulieu" (Chateau-Landon, France) caused a large landslide, leading to the death of seven people and destroying several houses. The sudden nature of the event and its concomitance with the flooding of the mine by the nearby “Loing” river have raised the hypothesis that the collapse was caused by the degradation of the mechanical properties of the chalk induced by the increase of saturation degree. To investigate this hypothesis and more generally, to better understand the mechanisms at the origin of instabilities in chalk mines, a large program including a laboratory characterization, in situ instrumentation and numerical modelling, was set up in 2011. Three underground chalk mines of the Paris Basin (France), including Chateau-Landon, were selected to study the geomechanical behavior of chalks subjected to changes in water saturation degree. Various series of laboratory tests have been undertaken, which allowed to advance in the understanding of the physical and mechanical water-chalk interactions. However, the extent of the phenomenon observed in Chateau-Landon could not be explained only by the reduction of the mechanical properties of chalk in the presence of water. In this context, it was decided to study the behavior of a neighboring and still accessible mine known as "Royer", located less than 500 m from the Beaulieu mine. This mine appeared as the ideal site to get further insights into the mechanisms responsible for this collapse. Indeed, this mine has extracted a similar material, and showed signs of instability in 2016 following exceptional climatic events for this region (177 mm of precipitation for the month of May and important flood of the Loing)
Autologous induced pluripotent stem cell-derived four-organ-chip
No full textInternational audienceMicrophysiological systems play a pivotal role in progressing toward a global paradigm shift in drug development. Here, we designed a four-organ-chip interconnecting miniaturized human intestine, liver, brain and kidney equivalents. All four organ models were predifferentiated from induced pluripotent stem cells from the same healthy donor and integrated into the microphysiological system. The coculture of the four autologous tissue models in one common medium deprived of tissue specific growth factors was successful over 14-days. Although there were no added growth factors present in the coculture medium, the intestine, liver and neuronal model maintained defined marker expression. Only the renal model was overgrown by coexisting cells and did not further differentiate. This model platform will pave the way for autologous coculture cross-talk assays, disease induction and subsequent drug testing
Prediction of maternal and foetal exposures to perfluoroalkyl compounds in a Spanish birth cohort using toxicokinetic modelling
No full textInternational audiencePrenatal exposures to perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) have been associated with child health outcomes, but many of these associations remain poorly characterized. The aim of this work was to provide new indicators of foetal exposure for the Spanish INMA birth cohort. First, a pregnancy and lactation physiologically based pharmacokinetic (PBPK) model was calibrated in a population framework to provide quantitative estimates for the PFOA and PFOS placental transfers in humans. The estimated distributions indicated that PFOA crosses the placental barrier at a rate three times higher than PFOS and shows a higher variability between mothers. The PBPK model was then used to back-calculate the time-varying daily intakes of the INMA mothers corrected for their individual history from a spot maternal concentration. We showed the importance of accounting for the mothers' history as different dietary intakes can result in similar measured concentrations at one time point. Finally, the foetal exposure was simulated in target organs over pregnancy using the PBPK model and the estimated maternal intakes. We showed that the pattern of PFOA and PFOS exposures varies greatly among the foetuses. About a third has levels of either one compound always higher than the levels of the other compound. The other two thirds showed different ranking of PFOA and PFOS in terms of concentrations in the target organs. Our simulated foetal exposures bring additional information to the measured maternal spot concentrations and can help to better characterize the prenatal exposure in target organs during windows of susceptibility
Fire tests carried out in FCH JU Firecomp project, recommendations and application to safety of gas storage systems
No full textInternational audienceIn the event of a fire, composite pressure vessels behave very differently from metallic ones: the material is degraded, potentially leading to a burst without significant pressure increase. Hence, such objects are, when necessary, protected from fire by using thermally-activated devices (TPRD), and standards require testing cylinder and TPRD together. The pre-normative research project FireComp aimed at understanding better the conditions which may lead to burst, through testing and simulation, and proposed an alternative way of assessing the fire performanceof composite cylinders. This approach is currently used by Air Liquide for the safety of composite bundlescarrying large amounts of hydrogen gas