International audience | Shredder organisms play a key role in rivers by feeding and fragmenting coarse organic matter that will then beexploited by other consumers. The effects of microplastics (MPs) on Gammarus sp., an ubiquitous genus offreshwater amphipods, and its shredding activity have been broadly investigated. However, the potentialbehavioral and physiological effects of different sizes of MPs on Gammarus sp. remain overlooked despite therecognized influence of MP size on MP toxicity. This study investigated the effects of a 28-day exposure to fourdifferent concentrations of two size fractions of PVC-microplastics (PVC-MPs), on Gammarus fossarum mortalityrate, feeding rate, assimilation efficiency, and expression of proteins involved in key processes. Increased mortalitywas observed for all treatments exposed to PVC-MPs, with higher mortality in the presence of smaller PVC-MPs at the highest concentration. No protein biomarker modulation was observed in presence of PVC-MPs,suggesting that no metabolic stress but direct physical damages of PVC-MPs might have led to the observedmortalities. No difference was observed for feeding rates, but a higher assimilation efficiency was measured forindividuals exposed to PVC-MPs, regardless of the concentration. This could be due to energy reallocation towardsdefense mechanisms or indicate a potential shift in digestive microbiota. This study highlighted thetoxicity of PVC-MPs, particularly of smaller sizes and even at relatively low concentration, for Gammarus fossarum.PVC-MP pollution may therefore alter the functional integrity of river ecosystems by reducing theabundance of shredder organisms and, subsequently, the process of leaf litter decomposition.

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.

International audience | Fishing gears are designed to catch marine species, but when lost at sea, they can continue to trap and kill aquatic life, a phenomenon known as ghost fishing. This study evaluated the use of a biodegradable twine made from poly(butylene succinate)/poly(butylene adipate terephthalate) (PBS/PBAT) in trawl fishing. The assessment included mechanical testing, trawl modelling, and seawater ageing simulations to explore potential loss scenarios. Mechanical tests indicated that the PBS/PBAT braid was about half as strong as high-density polyethylene (HDPE) but was suitable for braiding and netting. After 3 years in seawater, PBS/PBAT monofilaments showed biotic degradation, with strength losses of 20 % at 15 °C and 80 % at 25 °C. This suggests that gear made from this polymer would degrade faster than conventional gear if lost. Trawl modelling further demonstrated that trawl performance was only slightly affected by material change and ageing, highlighting the potential for reducing ghost fishing with less persistent twine.

International audience | More than 70 years of industrial production of per-and polyfluoroalkyl substances (PFAS) have resulted in their ubiquitous presence in the environment on a global scale, although differences in sources, transport and fate lead to variability of occurrence in the environment. Gull eggs are excellent bioindicators of environmental pollution, especially for persistent organic pollutants such as PFAS, known to bioaccumulate in organisms and to be deposited in bird eggs by maternal transfer. Using yellow-legged gull (Larus michahellis) eggs, we investigated the occurrence of more than 30 PFAS, including the most common chemicals (i.e., legacy PFAS) as well as their alternatives (i.e., emerging PFAS) in the Bay of Marseille, the second largest city in France. Compared to eggs from other colonies along the Mediterranean coast, those from Marseille had PFAS concentrations ranging from slightly higher to up to four times lower, suggesting that this area cannot be specifically identified as a hotspot for these compounds. We also found several emerging PFAS including 8:2 and 10:2 FTS, 7:3 FTCA or PFECHS in all collected eggs. Although the scarcity in toxicity thresholds for seabirds, especially during embryogenesis, does not enable any precise statement about the risks faced by this population, this study contributes to the effort in documenting legacy PFAS contamination on Mediterranean coasts while providing valuable novel inputs on PFAS of emerging concern. Identifying exposure in free-ranging species also participate to determine the main target for toxicity testing in wildlife.

International audience | <div><p>Aquaculture is crucial in meeting global seafood demand; however, intensification often leads to bacterial diseases that threaten productivity. Dicentrarchus labrax, a key species in European aquaculture, is highly vulnerable to vibriosis, primarily caused by Vibrio harveyi. This study investigates genetic profiles associated with vibriosis by analyzing V. harveyi strains from a seabass farm during 2022 vibriosis outbreaks. Sampling from biofilm and water environments yielded 946 bacterial isolates, of which 56 were identified as V. harveyi using MALDI-TOF MS. ERIC-PCR genotyping revealed four distinct profiles. Despite observing variability in the presence of the 80 tested virulence genes, the overall genetic variation among these profiles was not pronounced. Notably, no single genotypic profile was linked to vibriosis. These findings suggest that the presence of virulence genes alone may not predict disease outbreaks, thus highlighting the need for future research on environmental and transcriptional factors to improve disease control in aquaculture systems.</p></div>

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 | 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 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 | 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.

Agricultural use of pesticides continues to rise globally. Argentina ranks fifth in use. While pesticides help yields, they also pose risks to human health and the environment. Indoor dust can present high pesticide concentrations, raising concerns about chronic exposure in non-farming households. Studies of pesticides in indoor dust are few worldwide. This pioneering study aimed to identify and/or quantify for the first time pesticide occurrence in indoor dust from urban residences in the Pampas Region, southeast of Buenos Aires Province, Argentina. Pesticide residues in indoor dust from 48 non-agricultural homes in the Pampas plain region were analysed. Study participants completed questionnaires on household demographics, pet ownership, pesticide use, gardening, and habits like leaving shoes outside. We detected 41 out of 49 targeted pesticides, including metabolites and banned compounds. Seven of the 49 tested are dual-use compounds (i.e. pesticide & biocide or veterinary applications). The synergist piperonyl butoxide, the dual-use imidacloprid, and “agricultural only” pesticides carbaryl, glyphosate, and atrazine were detected in all dust samples. Glyphosate, 2,4-D, atrazine, imidacloprid, carbaryl, tetramethrin, and piperonyl butoxide had maximum concentrations exceeding 1, 000 μg kg−1. Complex mixtures of up to 32 residues were found per sample. Questionnaire responses revealed that most participants brought shoes inside (60 %), almost all had pets (93 %), and 51 % had used flea repellents (mainly imidacloprid and fipronil). Approximately 48 % reported pesticide use in the past year, and 19 % reported exposure via their (non-farmer) jobs, e.g., via disinfection and weeding. These findings highlight the prevalence of pesticide residues in residential settings and the need for further research on long-term exposure and risks. Improved tracking of agricultural, household, and mixed-use pesticide applications is crucial, particularly in regions heavily reliant on agriculture.