peer reviewed | Metconazole (MEZ), a chiral triazole fungicide, produces enantioselective adverse effects in non-target organisms. Among MEZ's isomers, cis-MEZ displays robust antimicrobial properties. Evaluating MEZ and cis-MEZ's toxicity may mitigate fungicide usage and safeguard non-target organisms. Our study evaluated the toxicity of MEZ and its cis-isomers at concentrations of 0.02, 0.2, 2, and 4 mg L−1. We report stereoselectivity and severe cardiovascular defects in zebrafish, including pericardial oedema, decreased heart rate, increased sinus venous and bulbous arteries distances, intersegmental vessel defects, and altered cardiovascular development genes (hand2, gata4, nkx2.5, tbx5, vmhc, amhc, dll4, vegfaa, and vegfc). Further, MEZ significantly increased oxidative stress and apoptosis in zebrafish, primarily in the cardiac region. Isoquercetin, an antioxidant found in plants, partially mitigates MEZ-induced cardiac defects. Furthermore, MEZ upregulated the Wnt/β-catenin pathway genes (wnt3, β-catenin, axin2, and gsk-3β) and β-catenin protein expression. Inhibitor of Wnt Response-1 (IWR-1) rescued MEZ-induced cardiotoxicity. Our findings highlight oxidative stress, altered cardiovascular development genes, and upregulated Wnt/β-catenin signaling as contributors to cardiovascular toxicity in response to MEZ and cis-MEZ treatments. Importantly, 1R,5S-MEZ exhibited greater cardiotoxicity than 1S,5R-MEZ. Thus, our study provides a comprehensive understanding of cis-MEZ's cardiovascular toxicity in aquatic life. © 2024 Elsevier Ltd

peer reviewed | Accurate interpretation of mercury (Hg) isotopic data requires the consideration of several biotic factors such as age, diet, geographical range, and tissue metabolic turnover. A priori knowledge of prey-predator isotopic incorporation rates and Hg biomagnification is essential. This study aims to assess Hg stable isotopes incorporation in an Arctic species of Phocidae, the hooded seal Cystophora cristata, kept in human care for 24 months (2012 - 2014) and fed on a constant diet of Norwegian Spring Spawning herring Clupea harengus. We measured THg, MMHg and iHg levels, as well as Hg stable isotope composition with both mass dependent (MDF) and mass independent (MIF) fractionation (e.g. δ202Hg and Δ199,200,201,204Hg) in hooded seal kidney, liver, hair and muscle, in addition to herring muscle. We then calculated Hg MDF and MIF isotopic fractionation between hooded seals and their prey. We found a significant shift in δ202Hg between hooded seal hair (+0.80‰) and kidney (-0.78‰), and herring muscle. In hooded seals tissues δ202Hg correlated positively with MMHg percentage. These findings suggest that tissue-specific Hg speciation is the major driver of changes in Hg isotopic fractionation rates in this Arctic predator. Δ199Hg, Δ200Hg, Δ201Hg and Δ204Hg values did not vary between herring and hooded seal tissues, confirming their utility as tracers of Hg marine and atmospheric sources in top predators. To our knowledge, this represents the first attempt to assess complex Hg isotope dynamics in the internal system of Arctic Phocidae, controlling the effects of age, diet, and distribution. Our results confirm the validity of Hg stable isotopes as tracers of environmental Hg sources even in top predators, but emphasize the importance of animal age and tissue selection for inter-study and inter-species comparisons. | 14. Life below water

This article reviews methods for estimating leaching of PFAS from contaminated materials. Given the variety of methods, selecting those that best simulate assessment objectives is essential. Specific scenarios requiring PFAS leaching assessment, such as leaving materials in place, reuse, and disposal, are discussed. The knowledge gaps presented could be used to improve existing leaching methods for better predictions and understanding of PFAS leachability. | publishedVersion

peer reviewed | Trace elements (TEs) remain of significant toxicological concern as many are critical for global decarbonisation. TEs accumulate in sediments so benthic polychaetes (e.g. Hediste diversicolor and Alitta virens) are highly relevant for ecotoxicology. However, ecological/biological differences could influence TE accumulation and biomonitoring suitability. Exploiting multiple sympatric populations (Solent, UK), we measure sediment and tissue concentrations generating EFs (enrichment factors), AEIs (Adverse Effects Indexes) and tissue bioaccumulation factors. We also assess stable isotope compositions to elucidate diet influences. Despite diverse anthropogenic activity in the Solent, the majority of TEs present low levels of sediment contamination at the sites. For Ni, Pb and As, a combination of mean AEIs >1 and some sediment concentrations exceeding SQVs (Sediment Quality Values) indicate a slight toxicological risk. For Cu and Hg, high EFs and AEI scores confirm they are the greatest risk, thus requiring source identification/control. However, only mean As tissue concentrations reflect contaminated sites, therefore, identifying the As-source(s) is also a priority. Sediment and tissue concentration relationships were generally negative and not significant for both species. Although a significant negative relationship for Cd for A. virens requires further investigation, the lack of evidence for TE bioaccumulation from sediment may limit both species' biomonitoring suitability for low-contamination sites. Species differences in tissue concentration were also TE specific: H. diversicolor had significantly higher concentrations for Ag, Cu, Hg, Ni and Zn, whilst the reverse was true for Cd, Fe, Cr and As. Whilst ecological differences and that feeding sources are site and species-specific (as evidenced by C, N and S stable isotopes analysis) cannot be ignored, the diverse tissue concentrations strongly suggest different TE regulation strategies per species. Together these data will be important for ecotoxicologists and regulators to select the 'best' polychaete biomonitor and assess TE toxicity under future global decarbonisation trajectories for TE inputs. | 14. Life below water

peer reviewed | In oceans, the noise generated by human activities has reached phenomenal proportions, with considerable harmful effects on marine life. Measuring this impact to achieve a sustainable balance for highly vulnerable marine ecosystems, such as coral reefs, is a critical environmental policy objective. Here, we demonstrate that anthropogenic noise alters the interactions of a coral reef fish with its environment and how this behavioural response to noise impairs foraging. In situ observations on the Moorea reef revealed that the damselfish Dascyllus emamo reacts to boat passage by moving closer to its coral bommie, considerably reducing the volume of water available to search for prey. Using boat noise playback experiments in microcosms, we studied D. emamo's behaviour and modeled its functional response (FR), which is the relationship between resource use and resource density, when feeding on juvenile shrimps. Similar to field observations, noise reduced D. emamo's spatial occupancy, accompanied by a lower FR, indicating a reduction in predation independent of prey density. Overall, noise-induced behavioural changes are likely to influence predator-prey interaction dynamics and ultimately the fitness of both protagonists. While there is an urgent need to assess the effect of anthropogenic noise on coral reefs, the ecological framework of the FR approach combined with behavioural metrics provides an essential tool for evaluating the cascading effects of noise on nested ecological interactions at the community level.

International audience | Fine particulate matter (PM2.5) in the atmosphere is of particular concern due to its adverse effects on human health and its impact on global warming. southeast Asia is a hot spot for fossil fuel combustion with recurrent release of large plumes spreading over the ocean and neighbouring countries. Due to the complex mixture of PM2.5, the atmospheric sources contribution related to local and regional emissions in Hanoi (northern Vietnam) is still ill-constrained. Here, we present a year-round study (November 2019 to December 2020) with measurements of 18 metals and metalloids (MM) and lead isotopes in the PM2.5 fraction to quantify weather-related atmospheric inputs and to assess risk to human health. Anthropogenic inputs from fossil fuel combustion accounted for about 80% in PM2.5. We found high PM2.5-bound MM concentrations often exceeding national and global standards with a low risk of chronic inhalation and carcinogenicity, mainly attributable to Cr. During winter monsoon (northeastern winds), stable weather conditions led to the enrichment of long-range air mass transport of local particulate emissions. During the summer monsoon (southeastern winds), warm and moist winds reduced coal contribution in PM2.5. Our study highlights the need for a strict implementation of policies to control hazardous MM emissions by reducing fossil fuel combustion. On the one hand, reducing coal-related activities could reduce Cr emissions and therefore improve the risks to human health. On the other hand, public policies should encourage conversion to green transport in order to reduce petrol combustion and thus limit global warming.

International audience | The cocktail of pesticides sprayed to protect crops generates a miscellaneous and generalized contamination of water bodies. Sorption, especially on soils, regulates the spreading and persistence of these contaminants. Fine resolution sorption data and knowledge of its drivers are needed to manage this contamination. The aim of this study is to investigate the potential of Mid-Infrared spectroscopy (MIR) to predict and specify the adsorption and desorption of a diversity of pesticides. We constituted a set of 37 soils from French mainland and West Indies covering large ranges of texture, organic carbon, minerals and pH. We measured the adsorption and desorption coefficients of glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D) and difenoconazole and acquired MIR Lab spectra for these soils. We developed Partial Least Square Regression (PLSR) models for the prediction of the sorption coefficients from the MIR spectra. We further identified the most influencing spectral bands and related these to putative organic and mineral functional groups. The prediction performance of the PLSR models was generally high for the adsorption coefficients Kdads (0.4 < R 2 < 0.9 & RPIQ > 1.8). It was contrasted for the desorption coefficients and related to the magnitude of the desorption hysteresis. The most significant spectral bands in the PLSR differ according to the pesticides indicating contrasted interactions with mineral and organic functional groups. Glyphosate interacts primarily with polar mineral groups (OH) and difenoconazole with hydrophobic organic groups (CH2, C=C, COO-, CO , CO -C). 2,4-D has both positive and negative interactions with these groups. Finally, this work suggests that MIR combined with PLSR is a promising and cost-effective tool. It allows both the prediction of adsorption and desorption parameters and the specification of these mechanisms for a diversity of pesticides including polar active ingredients.

International audience | Wetlands are among the most threatened ecosystems on the planet and pollution is a major factor causing the decline of wetland biodiversity. Despite the increasing use of pesticides, their fate and effects on freshwater reptiles remain largely unknown. We studied the European pond turtle (Emys orbicularis), a long-lived species at risk with a high exposure potential to pesticides. Between 2018 and 2020, we measured 29 pesticides and metabolites in 408 blood samples of turtles from two populations in the Camargue wetland (France). We were able to quantify 24 compounds and at least one pesticide or one degradation product in 62.5% of samples. Pesticide occurrences and concentrations were low, except for a herbicide widely used in rice cultivation and locally detected in water: bentazone that reached high blood concentrations in E. orbicularis. The occurrence and the concentration of pesticides in E. orbicularis blood depended mainly on the site and the sampling date in relation to pesticide application. Individual characteristics (sex, age, body condition) did not explain the occurrence or the concentration of pesticides found in turtle blood. Assessing the exposure of aquatic wildlife to a cocktail of currently-used pesticides is a first and crucial step before studying their effects at the individual and population levels.