Responses and structural recovery of periphytic diatom communities after short-term disturbance in some rivers (Hanoi, Vietnam)
Field transfer experiments of periphytic diatom assemblages developed on artificial substrates were set up to assess the responses of those communities to environmental disturbances. The glass slides were positioned for colonization at the relatively unpolluted site (Red, in the Red River) and at the heavily polluted site (TL, in the To Lich River) in the beginning of the experiment. After a period of 2 weeks, the colonized glass slides were concomitantly transferred from the unpolluted Red site to the heavily polluted TL site and to the moderate polluted site (NT 2, in the Nhue River) and, conversely, from the TL site to the Red site, and then to the NT 2 site. The responses and the adapting capacity of periphytic diatom communities to environmental changes were assessed through the cell density, diversity index, species richness, taxonomic composition, and diatom indices after 2 and 4 weeks of transfer periods. For all transfers except for the transfer from the Red to the TL site in which the growth inhibition of diatom cells was found, the diatom density significantly increased until the end of the experiment. Thus, the diatom communities have expressed their pollution tolerance or sensitivities by changing their composition to adapt themselves to environmental changes. Characteristic species of the Red site (Gyrosigma scalproides, Navicula recens) were replaced by Nitzschia palea, Nitzschia umbonata, Aulacoseira granulate typical species of the NT 2 site, in the biofilm transferred from the Red site to the NT 2 site. The relative abundances of typical diatom species of the Red site proliferated in the biofilm transferred from the TL site to the Red site. The replacement of periphytic diatom communities appeared after the transfer from the second week at the different sites. The slow shift of the species towards the typical species at the TL site could result from the organized structure of diatoms within biofilm before the transfer from the Red site to the TL site. The shifts in values of the Index of Specific Polluosensitivity and Diatom Assemblage Index to organic pollution throughout the experiment indicated the clear sensitivity of these indices to water quality changes.
(Journal of Applied Phycology. vol. 24, n° 0921-8971, pp. 1053-1065, 26/06/2026)
IRSTEA, UR REBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSTEA
Embryotoxic and genotoxic effects of heavy metals and pesticides on early life stages of Pacific oyster (Crassostrea gigas)
This study evaluated embryotoxicity and genotoxicity of two dissolved metals copper and cadmium (Cu and Cd) and two pesticides (metolachlor and irgarol) occurring in Arcachon Bay (SW France) in Pacific oyster (Crassostrea gigas) larvae and investigated the relationship between those two endpoints. Embryotoxicity was measured by calculating the percentage of abnormal D-shaped larvae and genotoxicity was evaluated with DNA strand breaks using the comet assay. After 24 h exposure, significant increases of the percentage of abnormal D-larvae and the DNA strand breaks were observed from 0.1µg/L for Cu, 10 µg/L for Cd and 0.01 µg/L for both irgarol and metolachlor in comparison with the controls. A strong positive relationship between embryotoxicity and genotoxicity was recorded for Cu, Cd and metolachlor. The current study suggests that copper, irgarol and metolachlor can induce larval abnormalities and DNA damage in a population of exposed oysters at environmentally relevant concentrations.
(Marine Pollution Bulletin. vol. 64, n° 0025-326X, pp. 2663-2670, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Événements extrêmes (submersion estuarienne et crue) dans le Médoc viticole : Quels changements environnementaux pour la qualité géochimique des eaux de l’estuaire de la Gironde ?
L’estuaire de la Gironde (sud-ouest de la France) a été marqué au cours de ces dernières décennies par des événements météorologiques majeurs (Tempêtes Martin en 1999, Xynthia en 2010), responsables d’importantes inondations (submersions estuariennes et crues). Dans un contexte de changements globaux (augmentation du niveau de la mer, urbanisation croissante, …), des incertitudes persistent quant à la fréquence de ces événements. A ces incertitudes s’ajoute une méconnaissance des impacts géochimiques sur la qualité des sols et des eaux de l’estuaire, consécutifs à la remise en eau temporaire des terrains riverains principalement viticoles, pouvant être fortement contaminés en certains métaux. A partir d’une base de données existantes sur les catastrophes naturelles (GASPAR) et d’une base météorologique, nous avons identifié les communes les plus sinistrées du Médoc sur lesquelles nous avons collecté des sols qui ont subi des tests de lixiviation en laboratoire. Pour cela, les sols ont été mis au contact avec de l’eau douce ou estuarienne afin d’identifier les processus de relargages ou piégeages en métaux et simuler, ainsi, l’impact des inondations. Les paramètres des tests de lixiviation ont été déterminés à partir de la détermination des caractéristiques des événements (type, durée, saison). Cette étude s’inscrit dans un programme de recherche pluridisciplinaire Adapt’eau (ANR CEP&S 2011), qui vise à étudier les impacts des changements globaux et à expérimenter des options d’adaptation sur l’environnement fluvio-estuarien Garonne-Gironde, notamment la dépoldérisation. Dans cette perspective, notre recherche apporte des éléments d’éclairage sur l’impact de la remise en eaux des terres viticoles sur la Garonne-Gironde.
(pp. 17, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR ADBX, IRSTEA
Evaluation of the efficiency of wastewater advanced treatments and sludge treatments through chemical analysis of 168 selected compounds and non-target analysis
The general objective of the ECHIBIOTEB research program (“Innovating tools for sampling, chemical and biological analyses for the diagnosis of wastewater advanced tertiary treatments and sludge treatments”, 2011-2014, financed by the French National Research Agency, coordinated by Irstea) is to use innovative and complementary tools to characterize the efficiency of water advanced treatments and sludge treatments in wastewater treatment plant. To achieve this goal, various strategies were combined: chemical analysis of a large panel of selected priority and emerging contaminants, non-target chemical analysis, in vitro and in vivo biological analysis and innovating sampling tools such as integrative samplers (e.g. POCIS (Polar Organic Chemical Integrative Sampler) and SPMD (Semi-Permeable Membrane Device)). Our presentation will focus on results on the chemical analyses of selected molecules and non-target analysis. Until today, 11 sampling campaigns, 8 for water and 3 for sludge, have been conducted. Among the potential treatments used for advanced (or tertiary) water treatments, ozone (O3), Granular Activated Carbon (GAC), O3 + GAC, ozone peroxide (H2O2) and UV/H2O2 were studied in full scale or large scale pilot design, located on the outlet of secondary biological treatments. For sludge treatments, solar dryer, compost and reed-bed filter were tested. A total of 138 contaminants belonging to pharmaceuticals, oestrogenic hormones, alkylphenols (AkP), Endocrine Disruptor Compounds (EDC), Polycyclic Aromatic Hydrocarbons (PAH) and pesticides were measured in the dissolved phase of water samples; and 113 contaminants, belonging to pharmaceuticals, oestrogenic hormones, AkP, EDC, organochlorine pesticides, PAH, PCB (PolyChloroBiphenyl) and PBDE (PolyBrominated DiphenylEthers) were measured in sludge samples. After extraction by adapted methods such as Liquid-Liquid Extraction, Solid Phase Extraction or Solid Phase MicroExtraction for waters, and Accelerated Solvent Extraction or microwave extraction for sludge, molecules were analysed by gas (GC) or liquid phase chromatography coupled with single or tandem mass spectrometry. Non-target analysis were realised with two-dimensional GC coupled to Time Of Flight mass spectrometer. For most of the compounds, targeted analysis showed a significant reduction in contaminant concentration in the dissolved phase of water after all tested treatments. Indeed, pharmaceuticals and AkP were efficiently eliminated with concentrations in effluents respectively about 100 and 10 times lower than in influents. In contrast, aminomethylphosphonic acid (AMPA) and glyphosate were not eliminated at all from secondary wastewaters. Many of the selected compounds are refractory to conventional secondary treatments; nonetheless, we demonstrated that they can be efficiently removed thanks to selected advanced tertiary treatments. In the presentation, we will discuss which treatment seems to be the most efficient to eliminate the selected compounds. Depending on the process and the contaminant class, concentrations in raw and treated sludge varied widely. Non-target analyses of 3 different sludge samples allowed to obtain a list of 190 molecules of interest, among which some nitrogen heterocyclic compounds as potential emerging contaminants. Further investigations are needed, especially combining chemical with biological analysis, to determine which compounds among these 190 would be the most relevant to be considered in environmental studies.
(pp. 19, 26/06/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Particle size distribution of nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) on traffic and suburban sites of a European megacity : Paris (France)
The size distribution of particulate nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) was determined during two field campaigns at a traffic site in summer 2010 and at a suburban site during the MEGAPOLI (Megacities : 5 Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) experiment in summer 2009. Both, OPAHs and NPAHs were strongly associated (>85 %) to fines particles (Dp < 2.5 µm) increasing the interest of their study on a sanitary point of view. Results showed really different NPAH and OPAH particle size distributions between both sites. At traffic site, 10 clearly bimodal (notably for NPAHs) particle size distributions (Dp = 0.14 and 1.4 µm) were observed, while the particle size distributions were more scattered at the suburban site, especially for OPAHs. Bimodal particle size distribution observed at traffic site for the NPAH could be assigned to the vehicle emissions and the particle resuspension. Broadest distribution observed at the suburban site could be attributed to the 15 mass transfer of compounds by volatilization/sorption processes during the transport of particles in the atmosphere. Results also showed that the combination of the study of particle size distributions applied to marker compounds (primary : 1-nitropyrene ; secondary : 2-nitrofluoranthene) and to NPAH or OPAH chemical profiles bring some indications on their primary and/or secondary origin. Indeed, 1,4-anthraquinone seemed 20 only primary emitted by vehicles while 7-nitrobenz[a]anthracene, benz[a]antracen7,12- dione and benzo[b]fluorenone seemed secondarily formed in the atmosphere.
(Atmospheric Chemistry and Physics. vol. 12, n° 1680-7316, pp. 8877-8887, 26/06/2026)
INERIS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Evaluation of advanced oxidation processes for the reduction of refractory micropollutants in treated wastewater
Complementary treatments can allow a reduction of concentrations of micropollutants to reach values compatible with a good state of the environment. Processes that seem more efficient to eliminate refractory substances from treated wastewater are advanced technologies similar to the ones used for drinking water production : ozonation, UV light, adsorption on activated carbon, membranes and advanced oxidation processes. Advanced oxidation processes (AOP) rely on the formation of HO° radical witch is less selective than ozone and has higher reaction constants. An advanced oxidation processes pilot was tested in two plants. The AOP pilot is a container with two reactors in parallel (O3/H2O2 and O3/H2O2/UV). Mass balances were performed based on wastewater flow and micropollutants concentration data at the inlet and at the outlet of the studied processes. All advanced oxidation processes tested were efficient on beta blockers and other drugs (>90%). The removal of alkylphenols was not complete with UV and hydrogen peroxide.
(pp. 2, 26/06/2026)
IRSTEA, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Etude intégrée de l’effet des apports amont et locaux sur le fonctionnement de la Garonne estuarienne (ETIAGE) : Rapport de synthèse année 1 Avril 2010 - Mars 2011
Le programme ETIAGE a été mis en place avec pour objectif de répondre aux questions suivantes : que représentent les apports des effluents de la Communauté Urbaine de Bordeaux (CUB) par rapport à ceux venant de l’amont en termes de charge organique et de micro-polluants ? Quels rôles sur le devenir des effluents jouent la présence du bouchon vaseux et la stagnation résiduelle des eaux (déplacement net entre mouvement de flot et de jusant) au niveau de l’estuaire fluvial amont en période d’étiage estival ? Réciproquement, à quels moments et jusqu’où s’étend l’impact de ces effluents sur la qualité des eaux de la Garonne estuarienne ? Quelles incidences des effluents sur le comportement des populations biologiques en place ou migratoires dans la Garonne estuarienne ? Quelle tendance évolutive va connaître l’oxygénation des eaux ? Quel sera l’impact sur le comportement des micro-polluants et des populations biologiques ? Quelles recommandations de gestion pourraient être préconisées à partir de la synthèse des pressions exercées sur les eaux de la Garonne estuarienne ? Le programme est divisé en 5 axes, dont les bilans de travail sont présentés axe par axe pour l’année 1, couvrant la période Avril 2010 – Mars 2011.
(pp. 36, 26/06/2026)
UR EPBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A new breaking wave height direct estimator from video imagery
Breaker height is a key parameter of nearshore processes and the demand for a continuous remote estimator is pressing. In this paper we present a standalone remote video-based method that estimates wave height at the breakpoint. Individual breaking events are first identified from changes in optical properties and wave height is further derived from the optical signature at the onset of breaking. An extended validation is performed using a dense wave basin dataset. The results show the ability of the method to measure individual breaker heights (9% of mean error, 18% RMS). In addition, the unique combination of in situ and remotely sensed data allows the estimation of two other breaking-related parameters, the height-to-depth ratio and wave front face slope, which show a substantial amount of dispersion. Because nearshore video systems are rapidly spreading over world coasts, this low-cost remote breaker height estimator should encounter large interest in coastal engineering studies.
(Coastal Engineering. vol. 61, n° 0378-3839, pp. 42-48, 26/06/2026)
PUC, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, UTFSM, LEGI, UJF, Grenoble INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Agulhas leakage as a key process in the modes of Quaternary climate changes
Heat and salt transfer from the Indian Ocean to the Atlantic Ocean (Agulhas leakage) has an important effect on the global thermo-haline circulation and climate. The lack of long transfer record prevents elucidation of its role on climate changes throughout the Quaternary. Here, we present a 1,350-ka accumulation rate record of the planktic foraminiferal species Globorotalia menardii. We demonstrate that, according to previous assumptions, the presence and reseeding of this fauna in the subtropical southeast Atlantic was driven by interocean exchange south of Africa. The Agulhas transfer strengthened at glacial ice-volume maxima for every glacial-interglacial transition, with maximum reinforcements organized according to a 400-ka periodicity. The long-term dynamics of Agulhas leakage may have played a crucial role in regulating meridional overturning circulation and global climate changes during the Mid-Brunhes event and the Mid-Pleistocene transition, and could also play an important role in the near future.
(Proceedings of the National Academy of Sciences of the United States of America. vol. 109, n° 0027-8424, pp. 6835-6839, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOCEAN, IPSL, ENS-PSL, PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, IP Paris, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS
An ocean–ice coupled response during the last glacial: a view from a marine isotopic stage 3 record south of the Faeroe Shetland Gateway
The rapid climatic variability characterising the Marine Isotopic Stage (MIS) 3 (∼ 60-30 cal ka BP) provides key issues to understand the atmosphere-ocean-cryosphere dynamics. Here we investigate the response of sea-surface paleoenvironments to the MIS3 climatic variability through the study of a high resolution oceanic sedimentological archive (core MD99-2281, 60 • 21 N; 09 • 27 W; 1197 m water depth), retrieved during the MD114-IMAGES (Interna-tional Marine Global Change Study) cruise from the southern part of the Faeroe Bank. This sector was under the proximal influence of European ice sheets (Fennoscandian Ice Sheet to the East, British Irish Ice Sheet to the South) during the last glacial and thus probably responded to the MIS3 pulsed climatic changes. We conducted a multi-proxy analysis of core MD99-2281, including magnetic properties, x-ray fluorescence measurements, characterisation of the coarse (> 150 µm) lithic fraction (grain concentration) and the analysis of selected biogenic proxies (assemblages and stable isotope ratio of calcareous planktonic foraminifera, dinoflagellate cyst-e.g. dinocyst-assemblages). Results presented here are focussed on the dinocyst response, this proxy providing the reconstruction of past sea-surface hydrological conditions, qualitatively as well as quantitatively (e.g. transfer function sensu lato). Our study documents a very coherent and sensitive oceanic response to the MIS3 rapid climatic variability: strong fluctuations, matching those of stadial/interstadial climatic oscillations as depicted by Greenland ice cores, are recorded in the MD99-2281 archive. Proxies of terrige-neous and detritical material suggest increases in continental advection during Greenland Stadials (including Heinrich events), the latter corresponding also to southward migrations of polar waters. At the opposite, milder sea-surface conditions seem to develop during Greenland Interstadials. After 30 ka, reconstructed paleohydrological conditions evidence strong shifts in SST: this increasing variability seems consistent with the hypothesised coalescence of the British and Fennoscandian ice sheets at that time, which could have directly influenced sea-surface environments in the vicinity of core MD99-2281.
(Climate of the Past. vol. 8, n° 1814-9324, pp. 1997-2017, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIMAG, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, NIOZ