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Where does the carbon go? A new carbon balance method to assess what happens to plastics under solar exposure
No full textInternational audiencePlastic pollution is a major and global threat to ecosystems and human health, resulting from the spreading and breakdown of plastic litter in the environment. In an aquatic environment, the first causes of this degradation are exposure to natural ultraviolet light and abrasion or collisions in the water. The extent of such degradation on a plastic object after a given time remains very difficult to quantify, especially regarding the relative production of microplastics, nanoplastics and soluble species along with volatile compounds. All of these degradation products may contribute differently to environmental pollution. Therefore, when evaluating the pollution caused by plastic objects, we should consider how much of each byproduct is generated. We propose a novel method based on conservation of the carbon mass during the degradation process. This approach is the first to enable quantification of carbon retrieved in each type of degradation product (Microplastics, Nanoplastics, Solubles, Volatile Compounds), as well as its evolution with exposure time. By applying this method to polypropylene granules, we demonstrate its effectiveness in tracking carbon footprint throughout the aging process. One of the unexpected results of this study is to show that the amount of carbon released in volatile form is far from negligible (17%) compared to MP (55%). The procedure we present is general enough to be applied to any type of polymer, and can be a valuable tool for assessing the amount of by-products of a given size released into the environment
An Original Approach to Determine the Minimum Operating Frequency of Mode-stirred Reverberation Chambers
No full textInternational audienceThe minimum operating frequency (MOF) of mode-stirred reverberation chambers is often assessed through statistical analysis using goodness-of-fit (GoF) statistical hypothesis tests such as Anderson-Darling or Kolmogorov-Smirnov. However, in the context of MOF determination, hypothesis tests are typically used with the aim of proving the null hypothesis made on the probability distribution of the electric field in the cavity, as opposed to the initial intent of the tests. A new approach avoiding hypothesis testing is proposed in this work by introducing a criterion based on normalized statistical distances. By normalizing the distances, it has been made possible to limit the influence of the sample size on the assessed minimum frequency, thereby improving the consistency of the results
Evaluation en laboratoire d'un dispositif de mesure en ligne du potentiel oxydant des aérosols
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Carpal tunnel syndrome and occupational co-exposure to biomechanical factors and neurotoxic chemicals using job-exposure matrices and self-reported exposure: Findings from the Constances cohort
No full textInternational audienceObjective To study the association between occupational co-exposure to biomechanical risk factors, potentially neurotoxic chemicals and carpal tunnel syndrome (CTS) in a large cohort of French workers, using two methods to estimate chemical exposure: job-exposure matrices (JEM) and self-reported exposure. Methods A randomly selected sample of adults were included between 2012 and 2018 in the French cohort CONSTANCES. Self-reported CTS was assessed using the first self-administered follow-up questionnaire, sent out approximately one year after baseline. Occupational exposure to biomechanical risk factors was assessed using self-administered questionnaire completed at inclusion. Lifetime occupational exposure to chemicals was assessed using two different methods: with JEMs and with a self-administered questionnaire completed at inclusion. Multivariate logistic regression models were used to evaluate the association between co-exposure to biomechanical risk factors and chemicals and CTS, adjusted for personal and medical factors and stratified by gender. Results For the analysis using JEM assessment, 35,941 workers (16,920 men and 19,021 women) were included: 261 men (1.5%) and 469 women (2.5%) declared having CTS at follow-up. There was an association between CTS and the co-exposure group: OR=2.37 [1.60–3.44] in men and OR=2.09 [1.55–2.77] in women, compared to the non-exposed group. For the self-reported chemicals analysis, 42,168 workers (20,877 men and 21,291 women) were included: 338 men (1.6%) and 532 women (2.5%) declared having CTS at follow-up. There was an association between CTS and the co-exposure group: OR=3.07 [2.28–4.08] in men and OR=2.68 [1.91–3.66] in women, compared to the non-exposed group. Conclusions The study showed an association between self- reported CTS and co-exposure to biomechanical risk factors and chemicals. This finding should be confirmed using more objective case definition of CTS, e.g. carpal tunnel release surgery
Temporal change of outdoor RF-EMF levels in four European countries: a microenvironmental measurement study
No full textInternational audienceIntroductionOver the past two decades, the amount of transmitted mobile data has increased rapidly. It is unknown whether the implementation of the new technologies enabling this has resulted in changes of outdoor radio-frequency electromagnetic fields (RF-EMF) exposure. Therefore, microenvironmental measurements were used to investigate temporal trends in RF-EMF exposure between 2016 and 2023, in the Netherlands, Switzerland, Belgium and Spain, following a similar protocol across campaigns. Microenvironmental measurements refer to exposure measurements performed at predefined small areas that have been differentiated with a specific function in that particular area. This allowed us to compare exposure trends between countries and years.MethodsThe data was collected as part of the ACCEDERA (2016–2018), ETAIN (2023), and GOLIAT (2023) projects, walking repeatedly the same routes with RF-EMF exposimeters. Identical microenvironments were identified in each country and measurements of the exposure from mobile base stations, mobile phones and the total exposure were compared across years.ResultsComparing measurements between 6 and 14 unique microenvironments in each country, our data did not suggest significant changes in the exposure from the mobile base station origin (total downlink exposure) between baseline measurements in 2016 to follow up and 2023 for the four countries. Across all countries and years the median values of the mobile base station exposure ranged from 0.11 mW/m2 (Switzerland, 2023) to 0.62 mW/m2 (Netherlands, 2018). There was no consistent trend in the individual microenvironments across the countries.ConclusionsOur measurements of RF-EMF outdoor exposure levels across included microenvironment groups do not indicate change in exposure levels between 2016 and 2023 despite an increase in mobile data traffic by a factor of 8 in Western Europe1
Bisphenol A induces sex-dependent alterations in the neuroendocrine response of Djungarian hamsters to photoperiod
No full textInternational audienceIn nature, species synchronize reproduction and energy metabolism with seasons to optimize survival and growth. This study investigates the effect of oral exposure to bisphenol A (BPA) on phenotypic and neuroendocrine seasonal adaptations in the Djungarian hamster, which in contrast to conventional laboratory rodents, is a well-recognized seasonal model. Adult female and male hamsters were orally exposed to BPA (5, 50, or 500 μg/kg/d) or vehicle during a 10-week transition from a long (LP) to short (SP) photoperiod (winter transition) or vice versa (summer transition). Changes in body weight, food intake, and pelage color were monitored weekly and, at the end of the exposure, expression of hypophysio-hypothalamic markers of photoperiodic (TSHβ, deiodinases), reproductive (Rfrp, kisspeptin) and metabolic (somatostatin, Pomc) integration, reproductive organ activity, and glycemia were assessed. Our results revealed sex-specific effects of BPA on acquiring SP and LP phenotypes. During LP to SP transition, females exposed to 500 μg/kg/d BPA exhibited delayed body weight loss and reduced feed efficiency associated with a lower expression of somatostatin, while males exposed to 5 μg/kg/d BPA showed an accelerated acquisition of SP-induced metabolic parameters. During SP to LP transition, females exposed to 5 μg/kg/d BPA displayed a faster LP adaptation in reproductive and metabolic parameters, along with kisspeptin downregulation occurring 5 weeks earlier and Pomc upregulation delayed for up to 10 weeks. In males, BPA exposure led to decreased expression of central photoperiodic integrators, with no effect on the acquisition of the LP phenotype. This pioneering study investigating EDCs' effects on mammalian seasonal physiology shows that BPA alters the dynamics of metabolic adaptation to both SP and LP transitions with marked sex dimorphism, causing temporal discordance in seasonal adaptation between males and females. These findings emphasize the importance of investigating EDCs’ effects on non-conventional animal models, providing insights into wildlife physiolog
5G Radiofrequency Exposure Reduces PRDM16 and C/EBP β mRNA Expression, Two Key Biomarkers for Brown Adipogenesis
No full textInternational audienceThe widespread use of wireless technologies has raised public health concerns about the biological effects of radiofrequency (RF) exposure. Children have a higher specific absorption rate (SAR) of radiation energy compared to adults. Furthermore, brown adipose tissue (BAT) is more prevalent in infants and tends to decrease with age. Previous animal studies demonstrated a cold sensation in rats exposed to 900 MHz (second generation, 2G). UCP1-dependent thermogenesis and BAT hyperplasia are two fundamental adaptive mechanisms initiated in response to cold. This study investigated the impact of short-term exposure to 2G and fifth generation (5G) on key thermogenic and adipogenic markers related to these mechanisms while considering age and exposure duration. Juvenile and young adult Wistar rats were randomized into three subgroups: a 5G group (3.5 GHz), 2G group (900 MHz), and a control group (SHAM). They were exposed to their respective continuous-wave RF signals for 1 or 2 weeks at an intensity of 1.5 V/m, with two exposure sessions of 1 h per day. After the exposure period, a RT-qPCR was carried out to evaluate the genetic markers involved in BAT thermogenesis and adipogenesis. Two adipogenic biomarkers were affected; a fold change reduction of 49% and 32% was detected for PRDM16 (p = 0.016) and C/EBP β (p = 0.0002), respectively, after 5G exposure, regardless of age and exposure duration. No significant RF effect was found on UCP1-dependent thermogenesis at a transcriptional level. These findings suggest that exposure to a 5G radiofrequency may partially disrupt brown adipocyte differentiation and thermogenic function by downregulating PRDM16 and C/EBP β, possibly leading to higher cold sensitivity
Réponse toxicologique des cellules BEAS-2B après exposition aiguë à l'interface air-liquide à l'éthylbenzène et au m-xylène seuls et dans des mélanges binaires
No full textInternational audienceBenzene, toluene, ethylbenzene, and xylenes (o‐, m ‐, and p ‐xylenes) constitute a family, named BTEX, of volatile organic compounds (VOCs) known for its toxicity. This study aimed to study the acute in vitro toxicity of ethylbenzene and m ‐xylene on human bronchial epithelial cells exposed at the air–liquid interface (ALI). The cells were exposed to VOCs alone and in a mixture for 1 h, followed by 5, 23, and 47 h of incubation. The kinetics of the cell response was characterized, including cytotoxicity, xenobiotic biotransformation, antioxidant defense system, inflammatory response, and apoptosis. The gene expression results showed major differences between these two compounds, even though their chemical structure is very similar. Ethylbenzene did not appear to be metabolized in BEAS‐2B cells, as it inhibited gene expression of xenobiotic metabolizing enzymes (XME) and did not induce antioxidant defense systems or apoptosis. However, a slight inflammatory response was observed after exposure. m ‐Xylene was metabolized in BEAS‐2B cells, inducing several XMEs and upregulating enzymes involved in the antioxidant defense system, as well as markers of inflammation and apoptosis. Co‐exposure to the binary mixture resulted in an inhibition phenomenon, resulting in the inhibition of toxic action mechanisms studied. The results provide new information on the toxicity of ethylbenzene and m ‐xylene and highlight the importance of conducting ALI exposures to mixtures of toxicants.Le benzène, le toluène, l'éthylbenzène et les xylènes (o-, m- et p-xylènes) constituent une famille, appelée BTEX, de composés organiques volatils (COV) connus pour leur toxicité. Cette étude visait à étudier la toxicité aiguë in vitro de l'éthylbenzène et du m-xylène sur des cellules épithéliales bronchiques humaines exposées à l'interface air-liquide (ALI). Les cellules ont été exposées aux COV seuls et en mélange pendant 1 heure, puis incubées pendant 5, 23 et 47 heures. La cinétique de la réponse cellulaire a été caractérisée, notamment la cytotoxicité, la biotransformation xénobiotique, le système de défense antioxydant, la réponse inflammatoire et l'apoptose. Les résultats de l'expression génique ont montré des différences majeures entre ces deux composés, même si leur structure chimique est très similaire. L'éthylbenzène ne semblait pas être métabolisé dans les cellules BEAS-2B, car il inhibait l'expression génique des enzymes métabolisant les xénobiotiques (XME) et n'induisait pas de systèmes de défense antioxydants ni d'apoptose. Cependant, une légère réponse inflammatoire a été observée après l'exposition. Le m-xylène a été métabolisé dans les cellules BEAS-2B, induisant plusieurs XME et régulant à la hausse les enzymes impliquées dans le système de défense antioxydant, ainsi que les marqueurs de l'inflammation et de l'apoptose. La co-exposition au mélange binaire a entraîné un phénomène d'inhibition, résultant en l'inhibition des mécanismes d'action toxiques étudiés. Les résultats fournissent de nouvelles informations sur la toxicité de l'éthylbenzène et du m-xylène et soulignent l'importance de mener des expositions ALI à des mélanges de substances toxiques
Threatened or thriving? Q methodology reveals stakeholder discourses of bats in an insular context
No full textInternational audienceBats are the only indigenous mammals on Reunion Island, with one of the three species, Mormopterus francoismoutoui, being endemic, and another, Pteropus niger, endangered. The endemic bat is highly adapted to urban areas and coexists in proximity to humans, living in large colonies in rooftops of houses, schools, and churches, and also under bridges. These bats hold considerable importance for Reunion Island’s natural heritage, but at the same time, they carry diseases and leave dejections that can cause olfactory discomfort and respiratory problems. As conservation and management measures hold profound implications on both human and bat populations, we need to foster a proper understanding of stakeholder perspectives and find common ground. We applied Q methodology to explore stakeholder discourses of bats on Reunion Island, focusing on aspects of conservation, management, and public health. Our combined quantitative and qualitative analyses revealed three principal discourses. The human-oriented discourse advocates public education and addressing myths and misconceptions to protect bats. The nature-oriented discourse prioritizes the protection of natural habitats to conserve bats. The public health and policy-oriented discourse seeks to adapt bat conservation and management policies to ensure public health safety. All stakeholders agreed that there is a lack of awareness among local media, which at times diffuses sensational and erroneous information, and that as well there is a need to integrate research output into public outreach efforts to garner interest in bats. These results can aid in contextualizing conservation actions and policies and could potentially provide sustainable management solutions to human-bat coexistence on Reunion Island