Non-stationary Model Free Parameter in Equilibrium Shoreline Modelling
The state-of-the-art equilibrium shoreline model proposed ShoerFor [1] is used to hindcast shoreline evolution. A similar approach to the work of Ibaceta et al. (2022) [2] is adopted, where they introduced non-stationary model free parameters to improve long term shoreline change predictions. An Ensemble Kalman Filter (EnKF) is implemented to track the temporal variability in model free parameters and explore if their evolution can be linked to the environmental forcing. A correlation between the winter wave energy and the model free parameter φ (beach memory) is identified where high energetic winters are followed by an increase in the parameter suggesting such time variation in beach memory can be parametrized.
(. vol. 42, pp. 646 - 651, 23/05/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, UNSW
Past trajectory of a Northwest Europe socio-ecosystem at the land-sea interface: Case study of the northern watersheds of the Bay of Brest over the last 150 years
The Bay of Brest (BB) is a macro-tidal estuarine environment that has been exposed to strong anthropogenic pressures over the past few decades, especially since the Second World War. This makes the BB an ideal site for studying coastal ecosystem transformations since the Industrial Revolution. We analysed five sediment cores collected in two key BB areas with varying exposure to marine hydrodynamic processes: i) the Elorn sector (3 cores) and ii) the Bay of Daoulas (2 cores) in the inner BB, close to the mouth of the Daoulas river. Our study used palynological (pollen and dinoflagellate cysts) and benthic foraminiferal assemblages, sedimentological data, and elemental geochemistry, at a very fine temporal resolution (2 to 16-year resolution). Working at a local spatial scale reveals robust correlations between the different driving forces and environmental changes over the last 150 years. Statistical analyses of these sedimentological and paleoecological time series reveal major breakpoints, specifically four key threshold periods: 1925–1938, 1960–1967, 1980–1987, and 2005, which are essential for understanding temporal changes in protist communities and the evolution of BB landscapes over this time period. Combining these findings with a reanalysis of regional precipitation patterns back to 1850, nutrient concentration data, and historical accounts of land-use practices, enables us to identify the main drivers of coastal ecosystem transformation. Our findings emphasize the strong influence of agricultural practices on trophic changes and the decline in the BB water quality, in agreement with coastal observatory series showing a notable increase in toxic algal blooms since the 1980s.
(Palaeogeography, Palaeoclimatology, Palaeoecology. vol. 690, n° 0031-0182, pp. 113703, 23/05/2026)
GEO-OCEAN, UBS, IFREMER, INSU - CNRS, UBO EPE, CNRS, BEEP, IFREMER, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOARCHI, UBS, UBO EPE, IBSHS, UBO EPE, ENS Rennes, GR, UR, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, LMBA, UBS, UBO EPE, CNRS
Colloid-facilitated release of PFAS from polluted-soil monoliths
Firefighting Aqueous Film Forming Foams contain per- and polyfluoroalkyl substances (PFAS). Because PFAS are persistent, firefighting training sites constitute a source of soil and groundwater contamination. Colloidal soil particles are known to facilitate the mobility of contaminants that have a strong affinity for soils. Indeed, colloid-facilitated transport of PFAS has been brought up repeatedly to discuss experimental observations regarding PFAS mobility. Still, it has only been observed experimentally for two PFAS molecules, using model experimental situations: repacked soil columns spiked with PFAS. We investigated for the first time the determinants and extent of colloid-facilitated transport of PFAS from AFFF-impacted undisturbed-soil monoliths during simulated rainfalls. These experiments showed that : (i) colloids contributed to the mobility—up to 70% of their concentration in leachates—of 12 PFAS having a perfluorinated carbon chain length nc ≥6, out of the 20 PFAS present in leachates; (ii) PFAS content in colloids was up to 25 times higher than in bulk soil, this enrichment stemmed from the adsorption on colloids of PFAS present in the soil solution; (iii) colloid-facilitated transport was exacerbated during transient flow regimes, which was probably related to the adsorption of PFAS and colloids to the moving air-water-interfaces. In addition, diffusion was the mechanism limiting the mobility of eight other PFAS with nc ≤7 and hydrodynamic conditions, linked to the soil structure, strongly affected the mobility of PFAS. The importance of colloidal particles as a carrier phase of PFAS calls for a renewed conceptual model of PFAS fate in soils.
(Journal of Hazardous Materials. vol. 511, n° 0304-3894, pp. 142279, 23/05/2026)
EMMAH, AU, INRAE, GERS-LEE, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSTV, BRGM, UA, ULR, Cerema, CNRS, INSIS - CNRS, IMT Atlantique, IMT, Nantes Univ, Nantes Univ - ECN, Nantes Univ, Nantes Univ - ENSA Nantes, Nantes Univ, Institut Agro
Sustainability ranking of antifouling coatings for leisure boats – Balancing efficacy and environmental impact
Antifouling coatings are widely used on leisure boats to prevent biofouling, yet their environmental impacts vary significantly depending on formulation. This study systematically evaluated seven commercial antifouling products, including five copper-based coatings (with varying cuprous oxide content), one tralopyril-based coating and one biocide-free silicone foul-release coating. The evaluation included three complementary approaches: field-based efficacy testing, environmental risk assessment (ERA) modeling and ecotoxicological assays. Field trials were conducted over six months at three European coastal sites (Skagerrak, Kattegat and Atlantic) to assess the antifouling performance. Biocide release rates were quantified using X-ray Fluorescence and used to model environmental risks in accordance with EU guidelines. Acute toxicity of leachates was tested on four marine species (Aliivibrio fischeri, Phaeodactylum tricornutum, Artemia salina larvae and Oryzias melastigma larvae). The biocide-free silicone coating ranked highest in sustainability, combining strong antifouling efficacy with minimal acute toxicity. The copper-based coatings typically showed comparable efficacy at all sites despite differences in copper release but some only passed ERA thresholds in one of the sites (Atlantic). Lower copper content formulations generally exhibited reduced environmental impact. The tralopyril-based coating, despite being marketed as “environmentally safe”, demonstrated the highest toxicity and environmental risk. These findings highlight the need for environmental assessment of antifouling products to validate environmental safety claims and to promote lower impact formulations. While ERA modeling is suitable for biocidal products, ecotoxicological testing remains essential for biocide-free alternatives. Improved and standardized leaching protocols are needed to better reflect real-world conditions and support sustainable product development.
(Journal of Hazardous Materials. vol. 506, n° 0304-3894, pp. 141600, 23/05/2026)
OFB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GU, DTU, UMR MARBEC, IRD, IFREMER, CNRS, UM
Determinants of residential pesticide contamination in vineyard regions: a structural equation modeling approach
Background Previous studies have associated pesticide exposure among people living near fields with adverse health outcomes. However, the factors influencing residential contamination by agricultural pesticides remain unclear. Objective This study aims to assess the effect of the local environment, home characteristics, and occupant behaviors on residential contamination. Methods In 2021, wipe samples from outdoor and indoor surfaces were collected in 28 homes in Bordeaux vineyard region during peak pesticide spraying. Eight fungicides were analyzed by LC-MS/MS or GC-MS/MS. Environmental, residential, and occupant-related data were gathered through questionnaires and databases. Using multilevel structural equation modeling, we simultaneously examined the effects of multiple factors on pesticide contamination outdoors (Model 1, n = 227 samples) and indoors (Model 2, n = 543 samples), reporting standardized beta coefficients. Results Outdoor pesticide contamination was positively associated with local vineyard areas (beta = 0.79, p = <0.001) and the probability of a recent pesticide application (beta = 0.34, p = 0.09). In contrast, daily wind speed (beta = -0.54, p = 0.001), cumulative rainfall over the past month (beta = -0.32, p = 0.03), and cleaning (beta = -0.37, p < 0.001) were negatively associated with outdoor contamination. Indoor contamination was significantly associated with the annual local purchases of pesticides (beta = 0.79, p < 0.001) and pesticide track-in by occupants (beta = 0.16, p < 0.001). Conversely, households with active adults and children (beta = -0.49, p < 0.01), cleaning (beta = -0.40, p < 0.001), and surface contact frequency (beta = -0.30, p < 0.001) showed significant negative associations. Air exchange exhibited only a weak suggestive association (beta = 0.07, p = 0.09). Both models demonstrated good fit indices. Significance These results improve our understanding of residential pesticide contamination and could help inform the design of strategies to reduce exposure in rural populations.
(Journal of Exposure Science and Environmental Epidemiology, n° 1559-0631, 23/05/2026)
CHU Bordeaux, BPH, UB, INSERM, Irset, UA, UR, EHESP, INSERM, Biosit : Biologie - Santé - Innovation Technologique, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECOSYS, INRAE
From Fixed to Transgressive Dunes, the Conditions and Timing of the Transition Along the Aquitaine Coast, France
Today most of the coastal dunes in temperate latitudes, especially in the northern hemisphere, are relatively stable. However, over the last decade, the Gironde coast, southwest France, has experienced substantial natural dune remobilization following a major marine erosion event. Annual, large-scale and high-resolution, airborne LiDAR data and Satellite imagery (Sentinel-2) are combined to address the coastal dune morphological changes and establish relations with forcing and controlling factors (vegetation cover, geomorphological descriptors). Between 2014 and 2023, about 10 out of 85 km of the Gironde dunes have switched from fixed to transgressive state. The analysis showed that in the vast majority of the cases the dominant process involved was dune front cannibalism. However, there is considerable spatial and temporal variability along the coast, depending on the vegetation cover evolution, the amount of sediment remobilized and the morphological characteristics of the dunes (steepness of the front slope, width)
(. vol. 41, pp. 10 - 15, 23/05/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS, ONF
Influence of Estuarine Turbidity Maximum Dynamics and River Discharge on Tide Propagation in Two Fluvial-Estuarine Systems
Tidal propagation in estuaries is shaped by the balance between morphological convergence and frictional effects, yet the influence of mud deposition associated with estuarine turbidity maxima remains unexplored. This study investigates the influence of Estuarine Turbidity Maxima (ETM) dynamics and river discharge on tidal propagation in the Loire and Gironde estuaries, combining frequency analysis of high-frequency observational data with an analytical model. Enhanced Harmonic Analysis reveals a tipping section-located downstream of the saline intrusion limit-in both hyperturbid systems, beyond which tidal properties (amplification, distortion, asymmetry) become highly sensitive to river discharge. Decomposing total friction into tidal, riverine, and interaction terms shows that the tipping point marks a regime shift where tide-river interaction dominates under low flow conditions, while the river term dominates during high discharge. Observations show that seasonal and interannual ETM-induced changes in bottom roughness can modulate tidal amplification by up to 35%, a mechanism confirmed by idealized modelling, while morphological changes have a more limited effect at these scales. Finally, scenario-based simulations suggest that sealevel rise and anthropogenic deepening may further enhance tidal amplification, 1 potentially promoting the upstream migration of salinity and turbidity maxima, with broader implications for estuarine functioning under future climate and human pressures.
(Estuaries and Coasts. vol. 49, n° 1559-2723, pp. 68, 23/05/2026)
RHITME, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOMA, UB, CNRS
Morphological Development and Evolution of Barchanoid Dunes on the Cap Ferret Coastal Spit
Barchans are crescent-shaped dunes with their convex side facing the wind and their horns pointing downwind, commonly observed in deserts but also in coastal environments. This study investigates the dune field of the Cap Ferret Spit (5-km wide, 23-km long; Atlantic Coast, SW France) including of series of barchanoids dunes, currently stabilized by forest cover. The aims are to classify each dune into distinct typologies and characterize their morphology in order to analyze their evolution. LiDAR-based analysis identified four distinct barchanoid dune types. Moreover, it revealed superimposed bedforms on the dunes, including draping and oscillating patterns, reflecting the influence of consistent wind regimes during dune development and migration. This study proposes an evolutionary sequence in which proto-barchans evolve into barchanoid ridges and eventually as mature isolated barchans. These findings provide insight into the geomorphological evolution of barchanoid dunes in a coastal context, and particularly their migration pattern on a coastal spit system
(. vol. 41, pp. 41 - 47, 23/05/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Sinking Together? Settling Behavior of Microplastics in the Presence of Fine Sediments
Predicting microplastic (MP) transport in aquatic environments requires understanding how particle properties, hydrodynamics, and aggregation processes control vertical transport, particularly in turbid systems. Here we investigate how particle physical properties and interactions with fine sediments influence the settling velocity of small MPs (<125 μm) under controlled laboratory conditions. We propose a novel methodology using an optical settling column (SCAF) to measure the settling velocity of MPs with contrasting sizes, shapes, and densities, both as dispersed particles and in mixtures with fine cohesive sediments at concentrations typical of turbid environments, under three treatments: dispersed, preagitated, and prerested. Settling velocities of dispersed MPs were primarily governed by size and density with minor shape effects. Empirical models developed for natural particles accurately predicted the MP settling in this size range. In MPsediment mixtures, the settling behavior varied markedly with particle properties and treatment conditions. Irregular particles, particularly fragments, exhibited flocculation under all treatments and higher settling velocities, whereas larger spheres interacted weakly with sediments and settled independently. Under prerested conditions, most particles showed enhanced and more uniform settling, with floc velocities converging around ∼0.5-0.6 mm/s. These findings offer insights into aggregation-driven vertical transport and provide a basis for improving predictive models in turbid environments.
(Environmental Science and Technology. vol. 60, n° 0013-936X, pp. 10251-10262, 23/05/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UAS, RHITME, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS
Late Holocene coastal sand-drift events and long-term socio-ecological resilience (Béniguet Island, Western France)
(Aeolian Research. vol. 76, n° 1875-9637, pp. 101048, 23/05/2026)
LETG - Brest, UBO EPE, UR2, CNRS, LETG, UBO EPE, UR2, CNRS, Nantes Univ - IGARUN, LETG, UBO EPE, UR2, CNRS, Nantes Univ - IGARUN, Nantes Univ, GR, UR, INSU - CNRS, CNRS, UBO EPE, CNRS, UP1, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Inrap