Caractérisation de la contamination métallique des sédiments dans les masses d’eau de la métropole bordelaise et analyses préliminaires de son effet sur la diversité piscicole
Dans un contexte d’une urbanisation croissante et de pressions anthropiques multiples (industrielles, domestique, agricole, trafic routier), les milieux aquatiques sont le réceptacle de grandes quantités de contaminants dont les éléments traces métalliques (ETM), historiques (e.g. Plomb [Pb], Zinc [Zn]) ou émergeants (e.g. Terres Rares REE). L’objectif général du travail s’appuie sur deux postulats : 1) La matrice sédimentaire est un bon intégrateur de la pollution engendrée à l’échelle des bassins versants dont les ETM pourraient être un bon proxy ; 2) Les poissons sont de bons indicateurs des perturbations anthropiques. Couplant deux postulats, cette étude vise à établir les relations potentielles entre la présence d’ETM dans les hydrosystèmes et la richesse et composition spécifique des peuplements de poissons dans les environnements urbains et péri-urbains de Bordeaux Métropole (Nouvelle Aquitaine, SO France). Pour cela, des pêches électriques ont été effectuées en 2018 et 2019, complétées par des prélèvements de sédiments. Une caractérisation physico-chimique des sédiments a été réalisée durant ce stage en déterminant la texture (granulométrie), les teneurs en Carbone Organique Total (COT) et en ETM sur la fraction totale (minéralisation triacide) et la fraction chimiquement disponible (digestion HCl 1M). Les concentrations brutes et normalisées (s’affranchissant de l’effet granulométrique) ont été comparées au bruit de fond géochimique régional et à des indices écotoxicologiques (TEC/PEC, Métox). Les analyses statistiques n’ont pas révélé de différence significative entre les sites, habitats et années. L’analyse préliminaire des relations entre les ETM et la composition spécifique des communautés de poissons n’a pas mis en évidence de lien statistique significatif entre les deux jeux de données. Les raisons possibles de cette absence de corrélation sont discutées, en particulier le rôle d’autres facteurs structurants négligés (e.g. physico-chimique, non intégration des ETM dissous ou de variables d’intégrité physique des cours d’eaux) et seront à investiguer pour de prochaines campagnes.
(pp. 56, 02/09/2026)
UR EABX, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact of nickel mining in New Caledonia on marbled eels Anguilla marmorata
New Caledonia is particularly affected by nickel open pit mining activities because of the presence of ultramafic soils rich in metal trace elements. The nickel particles dispersed by atmospheric transport and soil erosion during the excavation of nickel will end up by deposition or leaching in aquatic ecosystems where they may be bioaccumulated by living organisms in the rivers downstream the mines. Despite alarming freshwater metals concentrations, no study investigated the level of their bioaccumulation in eels living downstream mining sites, and if high bioaccumulation levels occur, the potential consequences on eel's health. The aim of this study was to determine how eels Anguilla marmorata are impacted in situ by metal concentrations issued from mining activity by measuring: morphometric parameters; metal concentrations in tissues and organs and transcription levels of target genes encoding proteins involved in several metabolic key functions. Among organs, liver was found to be the most affected by mining with average nickel concentrations of 5.14 mg/kg versus 1.63 mg/kg for eel liver away from mines leading to dysregulation of numerous genes involved in oxidative stress, DNA repair, apoptosis, reproduction and both lipid and mitochondrial metabolisms. This study should allow us to define in an integrated way if metals released by mining activities influence metals bioaccumulation in eels and induce biological effects.
(Journal of Hazardous Materials. vol. 436, n° 0304-3894, pp. 129285, 02/09/2026)
CRCTB, UB, CHU Bordeaux, INSERM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ISEA, UNC, UMS POREA, INSU - CNRS, CNRS, INRAE
Progress towards an international comparison of river sediment pollution: Key factors influencing metal concentrations along seven Western European Rivers (1945-2020)
Since 60 years, a large amount of data has been acquired to survey river sediment quality, especially concerning regulatory trace metals such as Cd, Cr, Cu, Hg, Ni, Pb, and Zn. Large-scale syntheses are still rare and show some limits to assess the effectiveness of public regulations and the river systems' resilience. Based on a sediment contamination database comprising more than 12,000 samples, we propose a first attempt to decipher spatio-temporal trends of metal contamination along seven major rivers in Western Europe (Garonne-Lot, Loire, Meuse Rhine, Rhone, Scheldt and Seine Rivers). Facing heterogeneous sampling and analytical methods on different sediment matrices (bed and flood deposits – BFD, suspended particulate matter – SPM, dated sediment cores – DSC), this work investigates the effect of analytical protocols, spatial and temporal factors on metal concentration trends. At a large scale, an increase in metal concentrations (especially for Cd, Pb and Zn) is reported along most of the investigated rivers. It appears closely related to major urban-industrial hotspots (Paris-Rouen corridor on the Seine River, Bonn-Duisburg corridor on the Rhine River, etc.) and to the geology of each watershed, both influencing the regional sediment quality. Former mining and metallurgical districts, generally located in crystalline areas, also caused high metal concentrations on the long term (Upper Loire River, Middle Meuse River, Lot River). A global decrease of metal concentrations is observed in all river sections since the 1960s-1970s onwards, in response to European and national regulations, and to socio-economical changes affecting urban-industrial areas. The high influence of the location of the samples along the rivers and the decade of sampling is confirmed by a Factor Analysis of Mixed Data (FAMD). Secondary factors such as the influence of the sediment matrix type (BFD, SPM and DSC) and the different digestion procedures prior to elemental analysis also explained significant differences for Cr, Cd, Cu, Pb, or Zn, although this can also be locally balanced by the substratum (i.e. for alkaline rivers). This approach points out the limitations of the available data, particularly regarding the need of regional geological backgrounds and the more systematic acquisition of ancillary data such as grain-size and TOC. It also provides critical clues to intercompare metal sediment pollution in rivers at large spatial and temporal scales worldwide.
(02/09/2026)
EVS, ENS de Lyon, Mines Saint-Étienne MSE, IMT, UL2, UJML, INSA Lyon, INSA, UJM, UJM EPE, ENTPE, ENSAL, CNRS, ALLHiS, UJM, UJM EPE, GéHCO, UT, NEOLAiA, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, LIVE, UNISTRA, CNRS, ITES, ENGEES, UNISTRA, INSU - CNRS, CNRS, LEHNA, UCBL, ENTPE, CNRS, ENTPE, ENTPE
Atmospheric Nitrous Acid Measurement in the French Landes Forest
(ACS Earth and Space Chemistry. vol. 6, n° 2472-3452, pp. 25-33, 02/09/2026)
IRCELYON-CARE, IRCELYON, UCBL, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LVEEM, UCA [2017-2020], CERI EE - IMT Nord Europe, IMT Nord Europe, IMT, IRCELYON, UCBL, INC-CNRS, CNRS
Extrinsic and intrinsic drivers of parasite prevalence and parasite species richness in a marine bivalve
Parasite species richness is influenced by a range of drivers including host related factors (e.g. host size) and environmental factors (e.g. seawater temperature). However, identification of modulators of parasite species richness remains one of the great unanswered questions in ecology. The common cockle Cerastoderma edule is renowned for its diversity and abundance of parasites, yet drivers of parasite species richness in cockles have not been examined to investigate the association of both macro and microparasite communities. Using cockles as a model species, some of the key drivers of parasite prevalence and parasite species richness were investigated. Objectives of this 19-month survey were to determine the influence of the environment, host-parasite dynamics and parasite associations on parasite species richness and prevalence at two different geographic latitudes, chosen based on environmental differences. The highest parasite species richness was recorded in the northern sites, and this was potentially influenced by a range of interactions between the host, the pathogens and the environment. Parasite prevalence increased with host size and age, and parasite species richness increased with reduced salinity. A number of interactions between parasites, and between parasites and pathologies may be influencing parasite infection dynamics. New and concerning information is also presented regarding interactions between parasites and their environment. A number of parasites and potential pathogens (bacteria, Trichodina ciliates, metacercariae, trematode sporocysts) may be advantaged under climate change conditions (warming seas, increased precipitation), increasing disease incidence, which may prove detrimental not just for cockles, but for other bivalve species in the future.
(PLoS ONE. vol. 17, n° 1932-6203, pp. e0274474, 02/09/2026)
UCC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impacts des produits phytopharmaceutiques sur la biodiversité et les services écosystémiques. Rapport de l’expertise scientifique collective
Chaque année, entre 55 000 et 70 000 tonnes de substances actives phytopharmaceutiques, incluant celles utilisables en agriculture biologique et de biocontrôle, sont vendues sur le territoire français métropolitain et d’outre-mer et sont utilisées pour la protection des cultures ou l’entretien des jardins, espaces végétalisés et infrastructures (JEVI). Dans le même temps, le rapport sur l’évaluation mondiale de la biodiversité et des services écosystémiques établi en 2019 par la Plateforme intergouvernementale scientifique et politique sur la biodiversité et les services écosystémiques (IPBES) dresse le bilan alarmant d’une érosion sans précédent de la biodiversité. La pollution chimique générée par les activités humaines, incluant les produits phytopharmaceutiques (PPP), est identifiée parmi les causes de cette érosion. Cette pollution s’ajoute à d’autres pressions, comme les destructions d’habitats causées par l’urbanisation, l’intensification des pratiques agricoles et sylvicoles, et les conséquences du changement climatique. Face à ce constat, la réglementation européenne en matière de mise sur le marché des PPP vise un degré élevé de protection, avec en particulier pour principe d’éviter tout effet inacceptable sur l’environnement. Toutefois, elle ne parvient pas complètement à atteindre cet objectif, en raison notamment d’une prise en compte insuffisante de la diversité des interactions telles qu’elles se produisent dans l’environnement (entre substances, entre organismes, avec une variété de facteurs physico-chimiques, etc.). C’est dans ce contexte que les ministres chargés de l’Environnement, de l’Agriculture et de la Recherche ont sollicité INRAE et l’Ifremer pour réaliser un état des lieux des connaissances scientifiques relatives aux impacts des PPP sur la biodiversité et les services écosystémiques. La précédente expertise scientifique collective (ESCo) portant sur Pesticides, agriculture et environnement avait été réalisée en 2005. Le présent exercice consiste à en actualiser les résultats, en les élargissant à l’ensemble du continuum terre-mer et en incluant les usages de PPP relevant des zones non agricoles (JEVI). A la différence de celle de 2005, cette ESCo est positionnée en aval de l’utilisation des PPP, pour traiter du devenir et des impacts de ces substances une fois introduites dans l’environnement. Elle ne traite pas des pratiques ou systèmes agricoles permettant de réduire les utilisations de PPP, ni des stratégies préventives de régulation des bioagresseurs. Ces thématiques font l’objet d’autres travaux en cours, notamment une autre ESCo conduite par INRAE sur la gestion des couverts végétaux pour la régulation naturelle des bioagresseurs dont les résultats sont attendus à l’automne 2022. Ces deux exercices s’inscrivent dans le cadre du Plan Ecophyto II+, en complément de l’expertise Pesticides et santé humaine publiée par l’Inserm en 2021. Le périmètre de la présente ESCo couvre les différents milieux (terrestre, atmosphérique, aquatiques continental et marin, à l’exception des eaux souterraines) dans leur continuité, du lieu d’application jusqu’à l’océan, en France métropolitaine et d’outre-mer, à partir de connaissances produites ou transposables dans ce type de contexte (climat, PPP utilisés, biodiversité présente, etc.). Il intègre tous les produits destinés à la protection des cultures ou à l’entretien des JEVI, qu’il s’agisse de PPP conventionnels ou de produits ou agents de biocontrôle, dès lors qu’ils sont susceptibles de se retrouver dans l’environnement du fait d’une utilisation actuelle ou plus ancienne. Le cadre d’analyse mis en place considère la biodiversité dans ses dimensions structurelle et fonctionnelle, et il intègre la question des services écosystémiques. L’attention est ainsi plus particulièrement portée sur des travaux qui documentent la mise en évidence des risques et des effets dans des conditions environnementales réalistes, et à des niveaux d’organisation biologique (ex. individu, population, communauté, écosystème) susceptibles de faciliter le lien à établir avec la biodiversité ainsi qu’avec les fonctions et services écosystémiques.
(pp. 1408 p., 02/09/2026)
ECOSYS, INRAE, RiverLy, INRAE, IFREMER, ISA, UNS, CNRS, INRAE, UniCA, LMGE, CNRS, UCA, UMR BAGAP, ESA, INRAE, Institut Agro, LPED, IRD, AMU, SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, EMMAH, AU, INRAE, MET, ENVL, INRAE, CRIOBE, UPVD, EPHE, PSL, CNRS, CNELIAS, ENS de Lyon, EHESS, AU, AMU, CNRS, LBBE, UCBL, VAS, CNRS, UB, UBFC, INRAE, Institut Agro, LCE, CNRS, UMLP, UBFC, UMR SAVE, UB, Bordeaux Sciences Agro, INRAE, DECOD, IFREMER, INRAE, Institut Agro, Institut Agro, OFB, GREDEG, UNS, CNRS, UniCA, UMR ITAP, INRAE, Institut Agro, LEREPS, UT Capitole, Comue de Toulouse, UT2J, Comue de Toulouse, ENSFEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR Eco&Sols, Cirad, IRD, INRAE, Institut Agro, IODE, UR, CNRS, UPR HORTSYS, Cirad, Cirad-PERSYST, Cirad, UMR MARBEC, IRD, IFREMER, CNRS, UM, AMURE, IRD, IFREMER, UBO EPE, CNRS, UR EABX, INRAE, IMBE, AU, AMU, CNRS, ICRA, UdG, BRM, IFREMER, URAFPA, UL, INRAE, UR HYCAR, INRAE, AQUA, INRAE, DipSO, INRAE, DEPE, INRAE
Mammal extinction facilitated biome shift and human population change during the last glacial termination in East-Central Europe
The study of local extinction times, together with the associated environmental and human population changes in the last glacial termination, provides insights into the causes of mega- and microfauna extinctions. In East-Central (EC) Europe, groups of Palaeolithic humans were present throughout the last glacial maximum, but disappeared suddenly around 15,200 cal BP. In this study cave sediment profiles dated using radiocarbon techniques and a large set of mammal bones dated directly by AMS 14C were used to determine local extinction times. These were, in turn, compared to changes in the total megafauna population of EC Europe derived from coprophilous fungi, the Epigravettian population decline, quantitative climate models, pollen and plant macrofossil inferred climate, as well as to biome reconstructions. The results suggest that the population size of large herbivores decreased in the area after 17,700 cal BP, when temperate tree abundance and warm continental steppe cover both increased in the lowlands. Boreal forest expansion started around 16,200 cal BP. Cave sediments show the decline of narrow-headed vole and arctic lemming populations specifically associated with a tundra environment at the same time and the expansion of the common vole, an inhabitant of steppes. The last dated appearance of arctic lemming was at ~ 16,640 cal BP, while that of the narrow-headed vole at ~ 13,340, and the estimated extinction time of woolly mammoth was either at 13,830 (GRIWM) or 15,210 (PHASE), and reindeer at 11,860 (GRIWM) or 12,550 cal BP (PHASE). The population decline of the large herbivore fauna slightly preceded changes in terrestrial vegetation, and likely facilitated it via a reduction in the intensity of grazing and the concomitant accumulation of plant biomass. Furthermore, it is possible to conclude that the Late Epigravettian population had high degree of quarry-fidelity; they left the basin when these mammals vanished.
(Scientific Reports. vol. 12, n° 2045-2322, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Video-Based Nearshore Bathymetric Inversion on a Geologically Constrained Mesotidal Beach during Storm Events
Although geologically constrained sandy beaches are ubiquitous along wave-exposed coasts, there is still a limited understanding of their morphological response, particularly under storm conditions, which is mainly due to a critical lack of nearshore bathymetry observations. This paper examines the potential to derive bathymetries from video imagery under challenging wave conditions in order to investigate headland control on morphological beach response. For this purpose, a video-based linear depth inversion algorithm is applied to three consecutive weeks of frames collected during daylight hours from a single fixed camera located at La Petite Chambre d’Amour beach (Anglet, SW France). Video-derived bathymetries are compared against in situ topo-bathymetric surveys carried out at the beginning and end of the field experiment in order to assess the performance of the bathymetric estimates. The results show that the rates of accretion/erosion within the surf zone are strongly influenced by the headland, whereas the beach morphological response can be classified into three main regimes depending on the angle of wave incidence θp: (1) under deflection configuration (θp>0°), the alongshore sediment transport was trapped at the updrift side of the headland, promoting sand accretion. (2) Under shadowed configuration (θp<0°), the interruption of the longshore current drove a deficit of sand supply at the downdrift side of the headland, leading to an overall erosion in the surf zone. (3) Under shore-normal configuration (θp=0°), rip channels developed, and up-state beach transition was observed. A comparison between video-derived bathymetries and surveys shows an overall root mean square error (RMSE) around 0.49 to 0.57 m with a bias ranging between −0.36 and −0.29 m. The results show that video-derived bathymetries can provide new insight into the morphological change driven by storm events. The combination of such inferred bathymetry with video-derived surface current data is discussed, showing great potential to address the coupled morphodynamics system under time-varying wave conditions.
(Remote Sensing. vol. 14, n° 2072-4292, pp. 3850, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SIAME, UPPA
A remote sensing-based classification approach for river mouths of the Amazon-influenced Guianas coast
The mouths of the rivers on the 1500-km-long Guianas coast, South America, are strongly influenced by large mud banks migrating alongshore from the Amazon River. To probe this influence, a river-mouth morphological classification scheme was carried out from satellite images, complemented by data from rare previous studies of estuarine hydrodynamics. The classification highlights a variety of morphological and dynamic river-mouth types that are further influenced by both fluvial water discharge and fluvial catchment rock type. Three basic types are identified: (1) river mouths diverted westward by capes and spits built from multi-decadal to multi-millennial accumulation of mud supplied by the Amazon; among these, mouths close to the Amazon are fixed by bedrock surrounded by mud; (2) small river mouths in French Guiana fixed by outcrops of Precambrian rocks that form headlands devoid of Amazon mud; and (3) large river mouths characterized by high water discharge that imparts an orientation normal to the coast; the largest two belonging to this type (the Essequibo in Guyana and the Maroni on the border between French Guiana and Suriname) exhibit infilled mouths that are transitioning towards deltas. These river mouths show a tropical seasonal estuarine circulation regime strongly influenced by Amazon mud. The influence of mud from the distant Amazon constitutes a unique aspect of the river mouths on the Guianas coast. Field and modelling studies in the future will be needed in order to achieve better characterization of the influence of Amazon mud on the estuarine circulation systems and of the distribution of sediment types within these river mouths, including sand supplied by the rivers.
(Regional Environmental Change. vol. 22, n° 1436-3798, pp. 65, 02/09/2026)
LEEISA, IFREMER, UG, CNRS, CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, IEPA, Cerema Direction Risques, Eau & Mer, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Cellular and molecular mechanisms of NiONPs toxicity on eel hepatocytes HEPA-E1: An illustration of the impact of Ni release from mining activity in New Caledonia
Anthropic activities such as open pit mining, amplify the natural erosion of metals contained in the soils, particularly in New Caledonia, leading to atmospheric emission of nickel oxide nanoparticles (NiONPs). These particles are produced during extraction end up in aquatic ecosystems through deposition or leaching in the rivers. Despite alarming freshwater Ni concentrations, only few studies have focused on the cellular and molecular mechanisms of NiONPs toxicity on aquatic organisms and particularly on eels. Those fish are known to be sensitive to metal contamination, especially their liver, which is a key organ for lipid metabolism, detoxification and reproduction. The objective of this study was to assess in vitro the cytotoxic effects of NiONPs on Anguilla japonica hepatocytes, HEPA-E1. HEPA-E1 were exposed to NiONPs (0.5-5 μg/cm2) for 4 or 24 h. Several endpoints were studied: (i) viability, (ii) ROS production, SOD activity and selected anti-oxidant genes expression, (iii) inflammation, (iv) calcium signalling, (v) mitochondrial function and (vi) apoptosis. The results evidenced that NiONPs induce a decrease of cell viability and an increase in oxidative stress with a significant superoxide anion production. An increase of mitochondrial calcium concentration and a decrease of mitochondrial membrane potential were observed, leading to apoptosis. These results underline the potential toxic impact of NiONPs on eels living in mining areas. Therefore, eel exposure to NiONPs can affect their migration and reproduction in New Caledonia.
(Chemosphere. vol. 303, Part 3, n° 0045-6535, pp. 135158, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CRCTB, UB, CHU Bordeaux, INSERM, CHU Bordeaux, UMS POREA, INSU - CNRS, CNRS, INRAE, ICMCB, UB, INC-CNRS, CNRS, BIC, UB, INSERM, CNRS