International audience | Once released into the environment, pesticides generate transformation products (TPs) which may be of (eco-)toxicological importance. Past studies have demonstrated the difficulty to predict pesticide TP occurrence and their environmental risk by monitoring-driven approaches mostly used in current regulatory frameworks targeting only known toxicologically relevant TPs. We present a novel combined approach which identifies and categorizes known and unknown pesticide TPs in soil by combining suspect screening time-of-flight mass spectrometry with in silico molecular typology. This approach applies an empirical and theoretical pesticide TP library for compound identification by both non-target and target time-of-flight (tandem) mass spectrometry and structural elucidation through a molecular structure correlation program. In silico molecular typology was then used to group the detected TPs according to common molecular descriptors and to indirectly elucidate their environmental properties by analogy to known pesticide compounds having similar molecular descriptors. This approach was evaluated via the identification of TPs of the triazole fungicide tebuconazole occurring in a field dissipation study. Overall, 22 empirical and 12 yet unknown TPs were detected and categorized into three groups with defined environmental properties. This approach combining suspect screening time-of-flight mass spectrometry with molecular typology could be extended to other organic pollutants and used to rationalize the choice of TPs to be intensively studied towards a more comprehensive environmental risk assessment scheme.

International audience | The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorlyinvestigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Somestudies have suggested that environmental exposure to PCBs and altered CORT secretion might beassociated. Here we investigated the relationships between blood PCB concentrations and circulatingCORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hencecovering a wide range of PCB exposure. Blood P7PCB concentrations (range: 61e115,632 ng/g lw) werepositively associated to baseline or stress-induced CORT levels in three species and negatively associatedto stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levelsgenerally increase with increasing blood P7PCB concentrations, whereas stress-induced CORT levelsdecrease when reaching high blood P7PCB concentrations. This study suggests that the nature of thePCB-CORT relationships may depend on the level of PCB exposure.

Currently, the geological storage of CO2 is heavily studied around the world in order to limit global warming due to the greenhouse effect. The atmospheric CO2, which has been steadily increasing for more than a century, is assumed to be in a large part responsible of this warming. Nowadays, various options have been considering to store CO2 in an underground environment for periods covering several centuries. Among the options, one is to inject it in unexploited coal seams. The objective of our work is to characterise the interactions between CO2 ans coal interfaces from two French coal seams. This will contribute to identify the most adapted coal basin which could be used for storing CO2 in France.

International audience | Urban streams that receive untreated domestic and hospital waste can transmit infectious diseases and spread drug residues, including antimicrobials, which can then increase the selection of antimicrobial-resistant bacteria. Here, water samples were collected from three different urban streams in the state of São Paulo, Brazil, to relate their range of Water Quality Indices (WQIs) to the diversity and composition of aquatic microbial taxa, virulence genes (virulome), and antimicrobial resistance determinants (resistome), all assessed using untargeted metagenome sequencing. There was a predominance of phyla Proteobacteria, Actinobacteria, and Bacteroidetes in all samples, and Pseudomonas was the most abundant detected genus. Virulence genes associated with motility, adherence, and secretion systems were highly abundant and mainly associated with Pseudomonas aeruginosa. Furthermore, some opportunistic pathogenic genera had negative correlations with WQI. Many clinically relevant antimicrobial resistance genes (ARGs) and efflux pump-encoding genes that confer resistance to critically important antimicrobials were detected. The highest relative abundances of ARGs were β-lactams and macrolide-lincosamide-streptogramin. No statistically supported relationship was detected between the abundance of virulome/resistome and collection type/WQI. On the other hand, total solids were a weak predictor of gene abundance patterns. These results provide insights into various microbial outcomes given urban stream quality and point to its ecological complexity. In addition, this study suggests potential consequences for human health as mediated by aquatic microbial communities responding to typical urban outputs.

International audience | Mice were exposed to a low dose of the model thyroid hormone disruptor, propylthiouracil. Although this had only a modest effect on maternal thyroid hormones production, postnatal analysis of the pups’ plasma by mass spectrometry and the brain striatum by RNA sequencing gave evidence of low lasting changes that could reflect an adverse effect on neurodevelopment. Overall, these methods proved to be sensitive enough to detect minor disruptions of thyroid hormone signalling in vivo.

International audience

International audience | <div><p>Aerated compost teas (ACTs) are rich in soluble humic substances (SHS) that have high affinity for metals, notably Cu. Using a batch experiment, we measured the extent to which two ACTs altered Cu dynamics in vineyard topsoils one day and 21 days after their addition. Soils were extracted with 0.01 M KCl, and total Cu concentration, free Cu ion fraction and size distribution of Cu ligands were measured in the extraction solution to assess the impact of ACT on the mobility of Cu. Diffusive gradient in thin film (DGT) measurements were carried out to assess the effect of ACT on Cu bioavailability, and the dissociation rate of Cu-SHS complexes was measured. The results revealed that ACT increased the mobility of Cu from a factor 1.2 to 5.8 depending on the soil, the ACT and the incubation time. Cu mobilization was associated with an increase in absorbance at 254 nm and a decrease in the free Cu ion fraction in the KCl extract. Associated with the strong agreement between the size distribution of SHS and that of Cu ligands in the KCl extract of soils treated with ACT, these results showed that Cu was mobilized through complexation by the SHS present in ACTs. A fraction of the SHS supplied with ACTs sorbed onto the soil constituents, notably in calcareous soils where this fraction reached 86% for ACT B. Between 15% and 50% of the SHS remaining in solution degraded between day one and day 21 under the presumed action of microflora. This explains why the Cu mobilization efficiency of ACTs was on average lower in calcareous soils than in non-calcareous soils, and decreased with time. Lastly, ACT increased the bioavailability of Cu in soils from a factor 1.3 to 4.2, due to the relatively high dissociation rate of Cu-SHS complexes.</p></div>

International audience | Mercury (Hg) is a metallic trace element toxic for humans and wildlife that can originate from natural and anthropic sources. Hg spatial gradients have been found in seabirds from the Arctic and other oceans, suggesting contrasting toxicity risks across regions. Selenium (Se) plays a protective role against Hg toxicity, but its spatial distribution has been much less investigated than that of Hg. From 2015 to 2017, we measured spatial coexposure of Hg and Se in blood samples of two seabird species, the Brünnich’s guillemot (Uria lomvia) and the black-legged kittiwake (Rissa tridactyla) from 17 colonies in the Arctic and subarctic regions, and we calculated their molar ratios (Se:Hg), as a measure of Hg sequestration by Se and, therefore, of Hg exposure risk. We also evaluated concentration differences between species and ocean basins (Pacific-Arctic and Atlantic-Arctic), and examined the influence of trophic ecology on Hg and Se concentrations using nitrogen and carbon stable isotopes. In the Atlantic-Arctic ocean, we found a negative west-to-east gradient of Hg and Se for guillemots, and a positive west-to-east gradient of Se for kittiwakes, suggesting that these species are better protected from Hg toxicity in the European Arctic. Differences in Se gradients between species suggest that they do not follow environmental Se spatial variations. This, together with the absence of a general pattern for isotopes influence on trace element concentrations, could be due to foraging ecology differences between species. Inboth oceans, the two species showed similar Hg concentrations, but guillemots showed lower Se concentrations and Se:Hg than kittiwakes, suggesting a higher Hg toxicity risk in guillemots. Within species, neither Hg, nor Se or Se:Hg differed between both oceans. Our study highlights the importance of considering Se together with Hg, along with different species and regions, when evaluating Hg toxic effects on marine predators in internationalmonitoring programs.

International audience | The gut microbiota is a collection of symbiotic microorganisms in the gastrointestinal tract. Its sensitivity to chemicals with widespread exposure, such as phthalates, is little known. We aimed to investigate the impact of perinatal exposure to phthalates on the infant gut microbiota at 12 months of age. Within SEPAGES cohort (Suivi de l'Exposition à la Pollution Atmosphérique durant la Grossesse et Effet sur la Santé), we assessed 13 phthalate metabolites and 2 di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH) metabolites in repeated urine samples collected in pregnant women and their offspring. We obtained stool samples from 356 children at 12 months of age and sequenced the V3-V4 region of the 16S rRNA gene, allowing gut bacterial profiling. We used single-chemical (linear regressions) and mixture (BKMR, Bayesian Kernel Machine Regression) models to examine associations of phthalates and DINCH metabolites, with gut microbiota indices of α-diversity (specific richness and Shannon diversity) and the relative abundances of the most abundant microbiota phyla and genera. After correction for multiple testing, di(2-ethylhexyl) phthalate (ΣDEHP), diethyl phthalate (DEP) and bis(2-propylheptyl) phthalate (DPHP) metabolites 12-month urinary concentrations were associated with higher Shannon α-diversity of the child gut microbiota in single-chemical models. The multiple-chemical model (BKMR) suggested higher α-diversity with exposure to the phthalate mixture at 12 months, driven by the same phthalates. There were no associations between phthalate and DINCH exposure biomarkers at other time points and α-diversity after correction for multiple testing. ΣDEHP metabolites concentration at 12 months was associated with higher Coprococcus genus. Finally, ΣDEHP exposure at 12 months tended to be associated with higher phylum Firmicutes, an association not maintained after correction for multiple testing. Infancy exposure to phthalate might disrupt children's gut microbiota. The observed associations were cross-sectional, so that reverse causality cannot be excluded.