PAHs and fish-exposure monitoring and adverse effects-from molecular to individual level
Polycyclic aromatic hydrocarbons (PAHs) are a diverse family of more than one hundred compounds, containing at least two aromatic rings. In addition to parent compounds, the PAH family also includes substituted derivatives, bearing one or several alkyl groups, sulfur, or oxygen. In the environment, PAHs are ubiquitous and present as very complex mixtures. They can also be associated with metallic and/or other organic compounds. The composition of PAH mixtures depends on their origin. There are two major types of such PAH mixtures, petrogenic and pyrogenic, which enter the environment through different routes. Petrogenic mixtures originate from oils, including natural oil seeps. They enter the aquatic environment due to harbor activity or soil runoff or as a consequence of oil spills. Pyrolytic mixtures result from the incomplete combustion of organic matter, including fossil fuel, entering aquatic environments through deposits of atmospheric emissions directly into water or soil, followed by soil erosion and runoff. Directly linked to human activity, the release of PAHs into the environment has increased over the last few decades. As an example, the amount of PAHs released into the atmosphere has dramatically increased from under 50,000 tons in 1987 (Eisler 1987) to over 500,000 tons in 2004 (Zhang and Tao 2009)
(Environmental Science and Pollution Research. vol. 21, n° 0944-1344, pp. 13685-13688, 22/04/2026)
LPGP, INRA, Biosit : Biologie - Santé - Innovation Technologique, BE, IFREMER, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Flash rip dynamics on a high-energy low-tide-terraced beach (Grand Popo, Benin, West Africa)
Rip currents are wave-driven intense seaward-flowing jets of water that are important to both beach morphodynamics and the overall ecosystem. Rip currents are also the leading deadly hazard to recreational beach users worldwide. More specifically, the African region is reported to have the highest rates of drowning in the world, yet both the occurrence and the type of rips developing along the African beaches are unknown. In February 2013, a 12-day field experiment was performed at the high-energy low-tide-terraced sandy beach of Grand Popo beach (Benin, West Africa). Human drifter data and video imagery are combined to address wave-driven circulation and rip current activity. Results show two prevailing rip current types. (1) Low-energy (~0.2-0.4 m/s) swash rips, with short life-spans of about 1 minute, extend about 5-10 m offshore and occur preferably at mid to high tide at fixed locations in the center of beach cusps. (2) Higher-energy (0.2 - 0.8 m/s) surfzone flash rips become active with the onset of intense wave breaking across the low-tide terrace. They tend to migrate downdrift with alonger time-span of about 2-5 minutes. The relatively weak longshore current (0.2 - 0.55 m/s) measured during the experiment suggests that flash rips were driven by vorticity generated by wave breaking rather than shear instabilities of the longshore current. Swash rips and flash rips are common at Grand Popo and often co-exist. We propose a conceptual model of both flash and swash rip activity on this stretch of the West African coast.
(Journal of Coastal Research. vol. SI 70, n° 0749-0208, pp. 633-638, 22/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOLA, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, IRD [France-Ouest]
Living (stained) deep-sea Foraminifera off Hachinohe (NE Japan, Western Pacific): environmental interplay in oxygen-depleted ecosystems
Live (Rose-Bengal stained) deep-sea foraminiferal faunas have been studied at five stations between 500–2000-m depth along the NE Japanese margin (western Pacific) to understand how complex environmental conditions (e.g., oxygen depletion, organic matter) control their structure (i.e., diversity, standing stocks, and microhabitats). All stations are characterized by silty sediments with no evidence of recent physical disturbances. The three stations located between 760–1250 m are bathed by dysoxic bottom waters (<45 μmol/L). Although high organic-carbon contents are recorded at all stations (>2.2% DW), only the oxygen-depleted sites are characterized by higher concentrations of sugars, lipids, and enzymatically hydrolysable amino acids (EHAA). Sedimentary contents in chlorophyllic pigments decrease with water depth without any major change in their freshness (i.e., [Chl a/(Chl a + Pheo a)] ratios). Both Uvigerina akitaensis and Bolivina spissa are restricted to the stations bathed by dysoxic waters, proving their oxygen-depletion tolerance. In such conditions, both phytophagous taxa are obviously able to take advantage of labile organic compounds (e.g., lipids and EHAA) contained in phytodetritus. Nonionella stella and Rutherfordoides cornuta survive in oxygen-depleted environments probably via alternative metabolic pathways (e.g., denitrification ability) and a large flexibility in trophic requirements. At stations where oxygen availability is higher (i.e., >70 μmol/L in bottom water) and where bioavailable organic compounds are slightly less abundant, diversity indices remain low, and more competitive species (e.g., Uvigerina curticosta, U. cf. U. graciliformis, Nonionella globosa, Nonionellina labradorica, and Elphidium batialis) are dominant.
(Journal of Foraminiferal Research. vol. 44, n° 0096-1191, pp. p. 281-299, 22/04/2026)
GM, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, JAMSTEC, CEFREM, UPVD, INSU - CNRS, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, NIOZ
Multi-agent modelling of the trajectory of the LBK Neolithic: a study in progress
(22/04/2026)
EVS, ENS de Lyon, Mines Saint-Étienne MSE, IMT, UL2, UJML, INSA Lyon, INSA, UJM, ENTPE, ENSAL, CNRS, ALLHiS, UJM, ArScAn, UP1, UP8, UPN, MCC, CNRS, UMR LISAH, IRD, INRA, Montpellier SupAgro, Montpellier SupAgro, BioArch, MNHN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Inrap, CEPAM, UNS, CNRS, REEDS, UVSQ
Geochemical composition of Trondheimsfjord surface sediments: Sources and spatial variability of marine and terrigenous components
High sedimentation rates in fjords provide excellent possibilities for high resolution sedimentary and geochemical records over the Holocene. As a baseline for an improved interpretation of geochemical data from fjord sediment cores, this study aims to investigate the inorganic/organic geochemistry of surface sediments and to identify geochemical proxies for terrestrial input and river discharge in the Trondheimsfjord, central Norway. Sixty evenly distributed surface sediment samples were analysed for their elemental composition, total organic carbon (C org), nitrogen (N org) and organic carbon stable isotopes (δ 13 C org), bulk mineral composition and grain size distribution. Our results indicate carbonate marine productivity to be the main CaCO 3 source. Also, a strong decreasing gradient of marine-derived organic matter from the entrance towards the fjord inner part is consistent with modern primary production data. We show that the origin of the organic matter as well as the distribution of CaCO 3 in Trondheimsfjord sediments can be used as a proxy for the variable inflow of Atlantic water and changes in river runoff. Furthermore, the comparison of grain size independent Al-based trace element ratios with geochemical analysis from terrigenous sediments and bedrocks provides evidence that the distribution of K/Al, Ni/Al and K/Ni in the fjord sediments reflect regional sources of K and Ni in the northern and southern drainage basin of the Trondheimsfjord. Applying these findings to temporally well-constrained sediment records will provide important insights into both the palaeoenvironmental changes of the hinterland and the palaeoceanographic modifications in the Norwegian Sea as response to rapid climate changes and associated feedback mechanisms.
(Continental Shelf Research. vol. 88, n° 0278-4343, pp. 61-71, 22/04/2026)
UiT, NGU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Single and mixture effects of pesticides and a degradation product on fluvial biofilms
The Morcille River located in the Beaujolais vineyard area (Eastern France) is subjected to strong vine-growing pressure leading to the contamination by a range of herbicides and fungicides of the surrounding freshwater environment. Particularly high concentrations of norflurazon, desmethyl norflurazon and tebuconazole were recorded in spring 2010 at the downstream site of the river. Despite their occurrence in rivers, scarce toxicity data are available for these products, in particular in the case of desmethyl norflurazon (main norflurazon degradation product). Furthermore, the toxicity data are generally available only for single compounds and are issued from single species toxicity tests, leading to a lack of ecological relevance. Consequently, this study was undertaken to evaluate the toxic effects of norflurazon, desmethyl norflurazon and tebuconazole singly and in a ternary mixture on fluvial biofilm. Toxicity tests were performed in microplates for 48 h. Photosynthetic endpointsweremeasured using pulse amplitude-modulated fluorometry; diatom densities and taxonomic composition were determined. After 48 h of exposure, significant effects on optimal quantumyield (Fv/Fm) for desmethyl norflurazon and mixturewere observed.
(Environmental Monitoring and Assessment. vol. 186, n° 0167-6369, pp. 3931-3939, 22/04/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Influence of sediment composition on PAH toxicity using zebrafish (Danio rerio) and Japanese medaka (Oryzias latipes) embryo-larval assays
Due to hydrophobic and persistent properties, polycyclic aromatic hydrocarbons (PAHs) have a high capacity to accumulate in sediment. Sediment quality criteria, for the assessment of habitat quality and risk for aquatic life, include understanding the fate and effects of PAHs. In the context of European regulation (REACH and Water Framework Directive), the first objective was to assess the influence of sediment composition on the toxicity of two model PAHs, benzo[a]pyrene and fluoranthene using 10 day-zebrafish embryo-larval assay. This procedure was undertaken with an artificial sediment in order to limit natural sediment variability. A suitable sediment composition might be then validated for zebrafish and proposed in a new OECD guideline for chemicals testing. Second, a comparative study of toxicity responses from this exposure protocol was then performed using another OECD species, the Japanese medaka. The potential toxicity of both PAHs was assessed through lethal (e.g. survival, hatching success) and sublethal endpoints (e.g. abnormalities, PMR and EROD) measured at different developmental stages, adapted to the embryonic development time of both species. Regarding effects observed for both species, a suitable artificial sediment composition for PAH toxicity testing was set at 92.5 % dw silica of 0.2-0.5 mm grain size, 5 % dw kaolin clay without organic matter for zebrafish and 2.5 % dw blond peat in more only for Japanese medaka. PAH bioavailability and toxicity were highly dependent on the fraction of organic matter in sediment and of the Kow coefficients of the tested compounds. The biological responses observed were also dependent of the species under consideration. Japanese medaka embryos appeared more robust than zebrafish embryos for understanding the toxicity of PAHs due to the longer exposure duration and it lower sensitivity of sediment physical properties.
(Environmental Science and Pollution Research. vol. 21, n° 0944-1344, pp. 13703 - 13719, 22/04/2026)
LIENSs, INSU - CNRS, ULR, CNRS, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPGP, INRA, Biosit : Biologie - Santé - Innovation Technologique
Persistent Organic Pollutants in a marine bivalve on the Marennes-Oléron Bay and the Gironde Estuary (French Atlantic coast) -Part 2: Potential biological effects
Contaminant effects on defence responses of ecologically and economically important organisms, such as the Pacific oyster Crassostrea gigas, are likely to influence their ability to resist infectious diseases, particularly at the young stages. The aim of this study was to explore the potential relationships between organic contaminants accumulated in the soft tissues of juvenile oysters, defence responses and physiological condition. Oysters were transplanted during summer and winter periods in different sites in the Marennes-Oléron Bay, the first area of oyster production in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Among the battery of biochemical and physiological biomarkers applied in the present work (superoxide dismutase -SOD-, catalase, glutathione peroxidase -GPx-, malondyaldehyde -MDA-, catecholase, laccase and lysozyme in gills, digestive gland, mantle and haemolymph, glycogen, proteins and lipids in the digestive gland and the condition index at the whole organism level), MDA and lysozyme in the digestive gland and SOD, GPx and laccase in plasma contibuted to significantly discriminate sites in which oysters bioaccumulated different levels of heavy polycyclic aromatic hydrocarbons (HPAHs), polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs) and lindane. These results strengthen the hypothesis that it is possible to differentiate sites depending on their contamination levels and biological effects by carrying out studies with transplanted juvenile oysters. In addition, correlations between antioxidant and immune defence responses and PAH and DDT body burdens in the first area of oyster production in France, the Marennes-Oléron Bay, and where massive oyster mortalities have been reported, suggest that the presence of organic chemical contaminants in the Marennes-Oléron Bay may influence defence responses in juveniles of C. gigas, and, therefore, could influence their ability to resist infectious diseases.
(Science of the Total Environment. vol. 514, n° 0048-9697, pp. 511-522, 22/04/2026)
PUJ, LIENSs, INSU - CNRS, ULR, CNRS, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Fluid Seepage in Relation to Seabed Deformation on the Central Nile Deep-Sea Fan, Part 1: Evidence from Sidescan Sonar Data,
The central Nile Deep-Sea Fan contains a broad area of seabed destabilisation in association with fluid seepage: slope-parallel sediment undulations are associated with multibeam high-backscatter patches (HBPs) related to authigenic carbonates. During the 2011 APINIL campaign, a deep-towed sidescan and profiling system (SAR) was used to acquire high-resolution data along three transects across water depths of 1,700-2,650 m. Three seabed domains are distinguished, all developed within stratified sediments overlying mass-transport deposits (MTDs). Upslope of the undulations (<1,950 m), sidescan HBPs record focused fluid seepage via seabed cracks. In the western area of undulations, sidescan HBPs are distinct from intermediate-backscatter patches (IBPs) that extend up to 850 m parallel to the undulations, mainly along their downslope flanks; some contain sub-circular HBPs up to 300 m wide, three associated with smaller (<10 m) hydroacoustic gas flares. Focused fluid seeps are inferred to have shifted over time to form elongate carbonate pavements, preferentially along the footwalls of faults beneath the undulations that provide pathways for fluid flow. In contrast, in the eastern area of undulations, sidescan imagery reveal only slope-transverse furrows formed by turbulent flows, interpreted to indicate that fossil carbonates sampled during submersible operations have been exhumed by erosion.
(Advances in Natural and Technological Hazards Research. vol. 37, pp. 129-139, 22/04/2026)
GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], UniCA, OGS, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Contributions and potential impacts of seven priority substances (As, Cd, Cu, Cr, Ni, Pb, and Zn) to a major European Estuary (Gironde Estuary, France) from urban wastewater
Urban wastewater metal inputs into coastal systems are of increasing interest to both scientists and managers facing restrictive environmental protection policies, population increase and changing metal applications. However, their impact and contribution to metal loads in estuarine and coastal environments is widely unknown due to the lack of (i) monitoring in both artificial and natural aquatic systems and (ii) an understanding of control parameters, such as spatial and temporal variations in hydrological conditions. We investigated the daily concentrations, fluxes and dynamics of seven EU priority contaminants (potentially toxic metals Cd, Cu, Cr, Ni, Pb, Zn and the metalloid As) transported by the Garonne River (La Réole site; watershed area ~ 57,000 km2) to those released into the freshwater reaches of the Gironde Estuary (Garonne Branch) by two main wastewater treatment plants (WWTPs) of Bordeaux under low river discharge and contrasting rainfall situations. During short intense summer rainstorms, wastewater flow into the WWTPs increased by up to 150% and 60%, respectively, resulting in an increase of 70% (As) to 200% (Pb) for fluxes entering the treatment plants. Overall resulting WWTP particulate and dissolved effluent concentrations were up to 2 (Cr), 3 (Pb, Cu and Ni) and 5 (Cd and Zn) times higher than measured upstream in the Garonne River, respectively. During low-discharge, maximum outlet fluxes at the WWTPs were similar to respective watershed-derived fluxes in the Garonne River. During rain events, Pb in all fractions, total and dissolved Cu and total and particulate Zn fluxes entering the fluvial estuary were close to the respective minimum flux values at the La Réole site. Furthermore, during rain episodes, particulate Cu and dissolved Zn fluxes from the WWTPs to the fluvial estuary were greater than those transported by the Garonne River at the La Réole site. Mixing of treated wastewater with highly turbid estuarine freshwater most likely results in a re-equilibration between the dissolved and particulate phases, although biogeochemical processes in downstream estuarine turbidity and salinity gradients may partly reverse contaminant adsorption on estuarine particles. Accordingly, urban wastewater contaminant release clearly impacts estuarine water quality before being expulsed to the Bay of Biscay.
(Marine Chemistry. vol. 167, n° 0304-4203, pp. 123-134, 22/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS