Etude comparative de l’écodynamique de micropolluants organohalogénés historiques et d’intérêt émergent dans l’estuaire de Seine
Dans un contexte de changement global, les effets de la pollution d'origine anthropique sont importants. Cette pollution est liée à l'urbanisation, l'activité industrielle ou encore l'agriculture intensive. Ces multiples sources génèrent de nombreuses catégories de pollution, dont la pollution chimique. Afin de mieux comprendre l'écodynamique de certains polluants ubiquistes, toxiques et bioaccumulables, l'estuaire de Seine a été choisi car il constitue le réceptacle final d'un bassin versant soumis à une forte pression anthropique. Plusieurs compartiments y ont été étudiés. Quatre espèces d'oiseaux marins (goéland argenté : Larus argentatus ; goéland brun : Larus fuscus ; goéland marin : Larus marinus ; cormoran huppé : Phalacrocorax aristotelis) sentinelles, bioindicatrices, représentatives d’un niveau trophique élevé et ayant des habitats et des habitudes d'alimentation variés et caractéristiques des milieux estuariens ont été choisies afin de suivre leur imprégnation en différentes classes de contaminants historiques tels que les polychlorobiphényles (PCB), les pesticides organochlorés (OCP) et les polybromodiphényléthers (PBDE) et de contaminants d’intérêt plus émergents comme les composés per- et poly-fluoroalkylés (PFAS). Les PCB, l'hexabromocyclododécane (HBCDD) et les PFAS ont été également suivis dans le milieu de vie et le réseau trophique de la sole commune (Solea solea) afin d’appréhender les transferts du sédiment vers le biote, au sein du réseau trophique benthique, mais aussi entre les stades juvéniles d'un organisme d’intérêt halieutique et écologique majeur.
(30/03/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Benefit versus cost trade-offs of masting across seed-to-seedling transition for a dominant subtropical forest species
Masting is a common reproductive strategy regulating seedling regeneration in many perennial plant species. The evolutionary origins and functional benefits of masting have been explained by well-supported hypotheses relating to economies of scale of seed production. Nevertheless, our understanding of the potential costs of masting for the plant seed-to-seedling transitions remains limited. We tracked the seed fate and documented changes in the seed spatial distribution patterns during the seed-to-seedling transition process of Castanopsis fargesii, a dominant species of subtropical evergreen broad-leaved forests in China under natural conditions for more than 6 years. Masting resulted in a high proportion of seeds escaping predation by vertebrates and rodents, supporting the predator satiation hypothesis. However, it increased the pre-dispersal seed predation by insects, and decreased the seed germination rate due to a negative effect on seed mass. This resulted in seed-to-seedling transition rates during mast years to be roughly half as much as during non-mast years. In addition, masting negatively affected the spatial rearrangement of seeds, resulting in a spatial aggregative distribution pattern of newly germinated seedlings. The combined negative effects of smaller seeds and spatially aggregated seedlings reduced the survival rate of newly germinated seedlings at seedling establishment stage. Synthesis. Considering the whole seed-to-established seedling transition process, the benefits of masting on seedling recruitment due to the effective seed predator situation by vertebrates and rodents were decreased by the additional costs on seed mass, seed germination, seed spatial arrangement and seedling establishment. Our results highlight the importance of considering both the positive and negative effects of masting at each stage of the seed-to-seedling transition. Inferences based on seed predation and recruitment of newly germinated seedlings alone would lead to an overly optimistic conclusion about the benefits of masting. © 2021 British Ecological Society
(Journal of Ecology. vol. 109, n° 0022-0477, pp. 3087-3098, 26/03/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Monitoring of 53 contaminants of emergent concern: occurrence in effluents, sludges, and surface waters upstream and downstream of 7 wastewater treatment plants
(25/03/2021)
INERIS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ISA, UCBL, INC-CNRS, CNRS
Chronic feeding exposure to virgin and spiked microplastics disrupts essential biological functions in teleost fish
Toxicity of polyethylene (PE) and polyvinyl chloride (PVC) microplastics (MPs), either virgin or spiked with chemicals, was evaluated in two short-lived fish using a freshwater species, zebrafish, and a marine species, marine medaka. Exposures were performed through diet using environmentally relevant concentrations of MPs over 4 months. No modification of classical biomarkers, lipid peroxidation, genotoxicity or F0 behaviour was observed. A significant decrease in growth was reported after at least two months of exposure. This decrease was similar between species, independent from the type of MPs polymer and the presence or not of spiked chemicals, but was much stronger in females. The reproduction was evaluated and it revealed a significant decrease in the reproductive output for both species and in far more serious numbers in medaka. PVC appeared more reprotoxic than PE as were MPs spiked with PFOS and benzophenone-3 compared to MPs spiked with benzo[a]pyrene. Further, PVC-benzophenone-3 produced behavioural disruption in offspring larvae. These results obtained with two species representing different aquatic environments suggest that microplastics exert toxic effects, slightly different according to polymers and the presence or not of sorbed chemicals, which may lead in all cases to serious ecological disruptions.
(Journal of Hazardous Materials. vol. 415, n° 0304-3894, pp. 125626, 11/03/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSEA MARBEC, UMR MARBEC, IRD, IFREMER, UM, CNRS, MDH, UB, UMR MARBEC, IRD, IFREMER, UM, CNRS, GABI, INRAE
High-Sensitivity Permeation Analysis of Ultrasmall Nanoparticles Across the Skin by Positron Emission Tomography
Ultrasmall nanoparticles (US-NPs; <20 nm in hydrodynamic size) are now included in a variety of pharmacological and cosmetic products, and new technologies are needed to detect at high sensitivity the passage of small doses of these products across biological barriers such as the skin. In this work, a diffusion cell adapted to positron emission tomography (PET), a highly sensitive imaging technology, was developed to measure the passage of gold NPs (AuNPs) in skin samples in continuous mode. US-AuNPs (3.2 nm diam.; TEM) were functionalized with deferoxamine (DFO) and radiolabeled with 89Zr(IV) (half-life: 3.3 days, matching the timeline of diffusion tests). The physicochemical properties of the functionalized US-AuNPs (US-AuNPs-PEG-DFO) were characterized by FTIR (DFO grafting; hydroxamate peaks: 1629.0 cm–1, 1569.0 cm–1), XPS (presence of the O═C–N C 1s peak of DFO at 287.49 eV), and TGA (organic mass fraction). The passage of US-AuNPs-PEG-DFO-89Zr(IV) in skin samples was measured by PET, and the diffusion parameters were extracted thereby. The signals of radioactive US-AuNPs-PEG-DFO-89Zr(IV) leaving the donor compartment, passing through the skin, and entering the acceptor compartment were detected in continuous at concentrations as low as 2.2 nM of Au. The high-sensitivity acquisitions performed in continuous allowed for the first time to extract the lag time to the start of permeation, the lag time to start of the steady state, the diffusion coefficients, and the influx data for AuNPs permeating into the skin. PET could represent a highly valuable tool for the development of nanoparticle-containing topical formulations of drugs and cosmetics.
(Bioconjugate Chemistry. vol. 32, n° 1043-1802, pp. 729-745, 10/03/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Corrigendum: Invasive Aquatic Plants as Ecosystem Engineers in an Oligo-Mesotrophic Shallow Lake
(Frontiers in Plant Science. vol. 12, n° 1664-462X, 08/03/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Environments, climates and technological changes in Late Middle Palaeolithic in southwestern France
(08/03/2021)
IRAMAT-CRP2A, IRAMAT, UTBM, UO, UBM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPHE, PSL, LMJL, UN UFR ST, UN, CNRS
Chemical characterization of water extractable organic matter from plants: A better understanding of soil dissolved organic matter sources and path in permafrost thawing regions
(04/03/2021)
METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, UCLouvain, iEES Paris, IRD, SU, UPEC UP12, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Environmental Fate Modeling of Nanoplastics in a Salinity Gradient Using a Lab-on-a-Chip: Where Does the Nanoscale Fraction of Plastic Debris Accumulate?
The aim of this study is to demonstrate how the flow and diffusion of nanoplastics through a salinity gradient (SG), as observed in mangrove swamps (MSPs), influence their aggregation pathways. These two parameters have never yet been used to evaluate the fate and behavior of colloids in the environment, since they cannot be incorporated into classical experimental setups. Land-sea continuums, such as estuaries and MSP systems, are known to be environmentally reactive interfaces that influence the colloidal distribution of pollutants. Using a microfluidic approach to reproduce the SG and its dynamics, the results show that nanoplastics arriving in a MSP are fractionated. First, a substantial fraction rapidly aggregates to reach the microscale, principally governed by an orthokinetic aggregation process and diffusiophoresis drift. These large nanoplastic aggregates eventually float near the water's surface or settle into the sediment at the bottom of the MSP, depending on their density. The second, smaller fraction remains stable and is transported toward the saline environment. This distribution results from the combined action of the spatial salt concentration gradient and orthokinetic aggregation, which is largely underestimated in the literature. Due to nanoplastics' reactive behavior, the present work demonstrates that mangrove and estuarine systems need to be better examined regarding plastic pollution.
(Environmental Science and Technology. vol. 55, n° 0013-936X, pp. 3001-3008, 02/03/2021)
GR, UR, INSU - CNRS, CNRS, IPR, UR, CNRS, UAG, UPMC, UNS, CNRS, IPREM, UPPA, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULaval, INSU - CNRS, CNRS
Muted cooling and drying of NW Mediterranean in response to the strongest last glacial North American ice surges
Abstract The massive North Atlantic iceberg discharges of the last glacial period, the so-called Heinrich events (HE), resulted in atmospheric and oceanic responses of the Mediterranean region that remain poorly documented and understood. This paper focuses on the climatic phases termed Heinrich stadials (HS) 4 and 5 generated by the HE 4 and 5 that occurred during a period of similar intermediate global ice volume and greenhouse gas concentrations but with different iceberg discharges and orbital boundary conditions. Our comparison of sea surface temperature and salinity changes with deep water conditions in the Gulf of Lions (planktonic and benthic foraminifera δ18O and δ13C records) and regional pollen-based temperature and precipitation reconstructions in NW Mediterranean for these Heinrich stadials reveal a paradoxical situation. A lower North American iceberg discharge during HS 5 compared to HS 4 is associated with colder and drier conditions in the NW Mediterranean borderlands. During the moderate iceberg discharge of HS 5 a relatively high salinity in the Gulf of Lions lead to stronger Western Mediterranean Deep Water formation and mixing of the surface with the deeper layers. By contrast during HS 4, we suggest that the massive North Atlantic iceberg break-up decreased the salinity of the Gulf of Lions and reduced the wind stress in the Mediterranean, leading to the stratification of the Mediterranean water column and inducing limited upward mixing of cold water, resulting in regional atmospheric warming and wetting compared to HS 5. This work highlights the potential crucial role of local processes in modulating the regional response to a global climate change related with ice-sheet instabilities.
(Geological Society of America Bulletin. vol. 133, n° 0016-7606, pp. 451-460, 01/03/2021)
EPHE, PSL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRAMAT-CRP2A, IRAMAT, UTBM, UO, UBM, CNRS, GEO3BCN–CSIC, CSIC