International audience

International audience | Halong Bay (northern Vietnam) is heavily affected by human activities. Metals and metalloids (e.g., Al, Cu, Hg, Ni, Sb, Pb, V; MM) were used as proxies to assess the origin and transport of anthropogenic inputs. The chronology of inputs was examined according to different particle transport pathways using two sediment cores, one from coastal waters (HL) exposed to both atmospheric deposition and the Red River drainage, and the other from a small isolated lake on an islet (HT) receiving only atmospheric deposition. Higher accumulation rates were observed in HL (0.449 g cm -2 year -1 ) than in HT (0.069 g cm -2 year -1 ). In both cores, all anthropogenic MM fluxes are controlled by sedimentation processes regardless of their origin and transport pathways. Results show that coastal waters are strongly influenced by Red River drainage with specific events recorded in 1947 (Indochina War), 1960 (first five-year plan), 1974 and 1985 (flash flooding) and 2002 (Tuyen Quang Dam landslides). In HL core, the highest variabilities were observed for Cr, Hg, Ni, Pb and V with surface maxima of 67.7, 0.107, 26.0, 31.4, 82.2 µg g -1 , respectively. Geochemical ratios (Pb/Hg and V/Ni) showed specific signatures related to fossil fuel combustion. Estimated Pb deposition fluxes follow the increase in CO 2 emissions in the region.

National audience | À chaque étape de leur cycle de vie, les plastiques libèrent des débris, des particules et des molécules qui contaminent les écosystèmes terrestres, aquatiques et marins. Ils contribuent alors aux trois grandes crises environnementales : la pollution, la perte de biodiversité et le changement climatique.Aucune espèce n’est épargnée : de la tortue marine au phytoplancton, du blé au hérisson européen, en passant par le brochet ou le héron cendré, toutes sont concernées par cette pollution, en grande partie invisible car principalement composée de micro- et de nanoplastiques, désormais présente dans tous les compartiments de l’environnement.Issu d’un travail collectif réunissant plusieurs organismes de recherche et universités, cet ouvrage aborde les différentes facettes de ce problème devenu global. Il s’appuie sur les dernières avancées scientifiques ayant permis de mieux quantifier et caractériser cette pollution, d’en étudier les impacts sur la biodiversité et le fonctionnement des écosystèmes — via le biomonitoring, l’étude des espèces sentinelles, les recherches en écotoxicologie et d’autres approches innovantes. Les auteurs proposent également un cadre réglementaire, ainsi que des solutions ou alternatives à destination des politiques publiques pour faire face aux enjeux liés à cette menace.Cet ouvrage s’adresse autant aux décideurs qu’aux chercheurs, étudiants en écologie, biologie ou sciences de l’environnement, ainsi qu’aux citoyens soucieux de mieux comprendre les multiples formes que prend aujourd’hui la pollution plastique et les enjeux qu’elle soulève.

International audience | The French Moss Survey employs forest mosses as indicators to monitor the deposition of atmospheric substances, notably focusing on cadmium (Cd), a known carcinogenic and contributor to respiratory illnesses. This comprehensive study encompasses 55 variables to understand Cd accumulation in terrestrial mosses in France. These variables include moss species, tree cover, biogeographical markers, land use area, proximity to road and rail networks, soil concentration of Cd and atmospheric concentration and deposition of Cd using a physical model. The response variable undergoes a complementary log–log transformation to constrain prediction values within the maximum Cd content in mosses. We have built a regression model to improve predictions, considering the impacts of covariates in France. This model retains biogeographical effects, leading to data segmentation into four distinct biogeographical zones: Atlantic, Continental, Mediterranean and Alpine. Subsequently, zone-specific regression models are explored to refine predictions and consider the impacts of covariates specific to each region, such as those related to railways and roads of the Mediterranean zone. Our biogeographical models effectively mitigate spatial correlation issues and yield accurate predictions, as evidenced by the leave-one-out cross-validation assessment. Compared to ordinary kriging map, the regression prediction maps highlight the contributions of certain covariates, such as the EMEP atmospheric transport model, to areas with high Cd concentrations. Furthermore, these maps exhibit new areas with high (resp. low) Cd concentrations due to high (resp. low) values of the covariates.

International audience | The use of organic plastic additives (OPAs) in food packaging has led to their widespread presence in various foodstuffs. These additives, including mainly flame-retardants, bisphenols, UV-stabilizers and plasticizers, are known for their potential hazards and environmental impact. This review aims to comprehensively assess the contamination of food products by OPAs and evaluate their role as vectors of exposure to hazardous chemicals. A review of recent literature was conducted, focusing on studies that report on the presence and concentrations of OPAs in different food categories, including aquatic products, beverages, cereals, dairy products, eggs, oils, fats, meat, poultry, vegetables, fruits and other food categories. The review also examines regional variations in contamination levels and identifies the pollutants. Significant contamination of foodstuffs by OPAs are highlighted, with varying concentrations reported across different regions and food types. Potential sources of contamination include food-packaging materials and environmental pollution. This review also identifies research gaps and proposes future directions to improve the study of OPAs in food, aiming to enhance the reliability and comparability of findings while supporting efforts to mitigate contamination risks.

International audience | This review summarizes how salinity and temperature, two key global factors driven by climate change in freshwater systems, interact with other stressors on organisms in controlled small-scale factorial experiments at the population, individual, or subindividual level (excluding mesocosm and field studies). Despite the growing interest, research following all these criteria remains limited with 156 publications of which 50% analyzed stressors + salinity, 46% stressors + temperature, and only 4% involved the triple combination. Research on the combined effect of temperature and salinity predominantly focused on metals, pesticides, and, to a lesser extent, emergent contaminants, such as microplastics and nanomaterials, encompassing various biological models and responses. In general, increased temperature amplifies the single effect of stressors, whereas salinity leads to a higher diversity of responses, with similar proportions of synergisms and antagonisms. Fish (Salmoniformes, Perciformes, and Cypriniformes) were the most studied organisms. Among Crustacea, only cladocerans of the genera Daphnia and Ceriodpahnia were considered. The present review highlights the need to include other species that play key roles in freshwater food webs and to increase triple combination studies to understand complex interactions and develop adaptation and mitigation strategies to preserve the environment and its services in this changing world.

International audience | The strong pest pressure on intensive banana cultivation in the French West Indies led to the intensive use of chlordecone (an organochlorine insecticide) between 1972 and 1993. Due to its high toxicity for the population and the environment, many studies were conducted on the transfer of chlordecone over the last 20 years. However, most studies focused on the dissolved fraction of chlordecone, while the particle-bound fraction was understudied. Therefore, this study reconstructs pluri-decadal erosion rates ( 1980–2023) and associated chlordecone particle-bound transfers from soil and sediment cores sampled in a cultivated headwater catchment (Saint-Esprit, Martinique). Based on sediment accumulation analyses in an agricultural reservoir, high erosion rates ( 10 t ha−1 yr−1) were found in the investigated catchment during the study period, with values exceeding the estimated tolerable soil loss rate in tropical contexts ( 2.2 t ha−1 yr−1). Based on the analysis of soil cores sampled along a banana plantation hillslope, this study highlights the formation of colluvial deposits with high levels of chlordecone contamination. When these areas are affected by erosion processes, this leads to massive remobilization of particle-bound chlordecone to water bodies. Indeed, in sediment sampled in the downstream reservoir, we observed a drastic increase in these transfers since 2006, synchronous with changes in agricultural practices. This study therefore highlighted the occurrence of legacy contamination at toeslope positions, which was estimated to potentially persist for 4000 to 11,000 years. Such a residence time highlights the need to implement changes in land management to effectively reduce erosion of agricultural soils, particularly in areas identified as ”temporary deposition zones” for chlordecone contamination, in order to protect downstream water bodies from chlordecone transfer. To achieve this, agricultural practices that may increase soil erosion, such as herbicide application or intensive ploughing, should be minimized. Overall, this study improved our understanding of erosion and associated chlordecone transfers in tropical environments.

Following a number of meetings devoted to knowledge sharing, identification of key issues, and discussing the best ways to move forward, a wide international expert community is now able to provide recommendations regarding the monitoring of seafloor macrolitter through observation and imaging. As the seafloor constitutes a major sink for marine litter including plastics, it is important to acquire robust and extensive data on litter distribution, abundance, types and size ranges across marine habitats. This should be done through widely agreed, harmonised, and non-destructive methods encompassing advanced technologies. Training and capacity building are essential elements in this endeavour. Both new and legacy imagery are needed to establish baseline assessments and trends. Informing policy-making is indispensable for effective action through upstream and targeted measures, with seafloor macrolitter (and megalitter) being a vital part of the evidence base for global mitigation measures.

International audience | Surfactants are used for a variety of applications such as emulsifiers, solubilizers, or foaming agents. Their intensive production and use in pharmaceutical, cosmetic and agricultural products have resulted in their continuous discharge in the environment, especially via wastewaters. Surfactants have become a threat to living organisms as they interact with, and disrupt, cell membranes and macromolecules. Their effects have mainly been studied in aquatic species; however, terrestrial organisms are also threatened by these emerging contaminants. This study investigates the effects of two widely used nonionic surfactants, Tween-20 and Triton X-100, on key traits of larvae and adults of the fruit fly Drosophila melanogaster. We assessed the toxicity of the two surfactants on viability, development time, body size and food intake of the flies. The results revealed that both surfactants induced toxic effects on the drosophila flies leading to decreased viability, delayed development and lowered food consumption at the highest tested concentrations. Both surfactants proved to be toxic to flies, and, for all tested traits, Triton X-100 appeared more toxic than Tween-20. Our results might extend to other invertebrates. The widespread use of these substances, which then end up in the environment, should be regulated to mitigate their impacts on biodiversity and ecosystems.

International audience | Soil and the threats it faces nowadays are often underestimated by citizens. This is rather due to a lack of awareness than to a lack of interest. In France, the surface covered by private gardens is not negligible, as it represents 2% of the territory, which is four times larger than the area of natural reserves in the country. Therefore, ensuring the protection and preservation of healthy soils in these areas is of great importance. Citizen science is a good way to raise awareness about scientific issues. Using a scientific and educational approach, the citizen science project “La clé du sol,” funded by the Fondation de France coordinated by the evertéa Foundation, aimed to raise home gardeners’ awareness of soil complexity and how to maintain healthy soil, as well as help them realize the possible consequences of their practices. For 2 years, fourteen gardeners participated in the project which involved theoretical and practical workshops where cultivation practices were listed, garden soils were sampled, and their physico-chemical and biological parameters as well as contaminants were analyzed. The strength of this project was the close interaction between the gardeners, a local citizen association, agronomy students, and researchers to decipher and interpret the results and learn how to translate them into practical advice. The progress of the project is presented in this article. Moreover, the scientific, social, and educational contributions of “La clé du sol” as well as the challenges inherent in citizen science projects involving long-term citizen engagement will be discussed.