Utilisation de solutions isotopiquement enrichies pour l’analyse de l’exposition aux mélanges Cr(III)/Cr(VI) en écotoxicologie

International audienc

Ecotoxicity and speciation of Cr in a small ultramafic catchment.

International audienc

Development of a Recyclable Remediation System for Gaseous BTEX: Combination of Iron Oxides Nanoparticles Adsorbents and Electrochemistry

We designed a two-step green technique to remove and recycle selected gaseous air pollutants. The first step includes the assessment of adsorption efficiencies of BTEX (benzene, toluene, ethylbenzene, and xylenes) on magnetite, hematite, and their composite surfaces. Improvement of the synthesis method led to BTEX adsorption (>85%; 200 ppmv) on 1.0 g of nanoparticles within a time scale of minutes. The second element included the design of an electrochemical reactor for the regeneration of used nanoparticles. NaOH showed superior performance as an electrolyte in comparison to NaCl and Na₂CO₃. The stripping efficiency for cathodic regeneration was higher than the anodic one. Under optimized conditions, the stripping efficiency was up to 85%. Iron oxides nanoparticles were regenerated (∼90%). Using high-resolution transmission electron microscopy, X-ray diffraction, NanoScan, and Brunauer–Emmett–Teller, selected physical and chemical properties of nanosurfaces were analyzed, revealing that the physical properties of nanoparticles remained unchanged during the regeneration process

New insights in defining analogy to advance the science of a read-across framework: Starting with Dreissena spp. exposed to psychotropic drugs

International audienceCompounds designed to be biologically active at low doses, such as pharmaceutical compounds, raise environmental concern. Despite the amount of literature already published about their (eco-)toxicity, knowledge gaps still remain about their fate in organisms and their mechanisms and modes of action at these low environmental concentrations. Read-across is a technique for filling knowledge gaps in toxicology information by analogy between well-studied and poorly studied chemicals. This technique assumes that substances which are structurally similar will have reasonably similar physical-chemical properties, behave similarly, and elicit similar biological effects across species if their molecular targets are present. However, predictions can be difficult for aquatic invertebrates, as our knowledge on the existence and the functional roles of drug targets in these organisms is often incomplete. While direct read-across between mammals and aquatic invertebrates may be complicated, the same difficulty may exist between species phylogenetically close, since life history strategies and their ecology may influence species tolerance. The objective of our work is to address this issue on two freshwater bivalves commonly used in ecotoxicology, Dreissena polymorpha and Dreissena rostriformis bugensis. To test this, we expose organisms to different psychoactive compounds at environmentally-relevant concentrations, during 15 and 28 days; and we studied a targeted set of biomarkers, linked to important physiological functions (e.g. neuroendocrine system, energy metabolism and osmoregulation), and bivalve’s ecological role (e.g. filtration and mineral contents). These functions are expected to be disrupted in bivalves according to what we already know for humans or other non-target organisms. Potential differences between males and females are also assessed. In overall, our results showed strong differences in the fate and effects of these compounds to the two species, as well as differential sensitivity between males and females. By testing the impact of several confounding factors on our capacity to read-across between psychoactive compounds and between molluscs, we bring new knowledge to improve the environmental risk assessment of pharmaceuticals

Ecotoxicity of mixture of Cr (III) and Cr (VI) to freshwater algae

International audienc

Photosynthetic activity as a proxy for algal growth inhibition: relevance for the ecotoxicity assessment of the poorly soluble Cr(III).

Virtual congress because of the Covid-19 pandemic.Originally scheduled to take place in Dublin, Ireland.International audienc

Effets écotoxicologiques des eaux d’un ruisseau de tête de bassin ultramafique (Pluhuv Bor, République Tchèque) sur l’invertébré aquatique Daphnia magna

National audienc

Protective role of colloids against Cr and Ni ecotoxicity in a small ultramafic catchment

International audienc

Nickel and chromium speciation in a small ultramafic catchment: implications for elemental bioavailability to freshwater organisms

International audienc

Effects and bioaccumulation of Cr(III), Cr(VI) and their mixture in the freshwater mussel Corbicula fluminea

International audienceChromium has two main oxidation states, Cr(III) and Cr(VI), that can occur simultaneously in natural waters. Current consensus holds that Cr(VI) is of high ecotoxicological concern, but regards Cr(III) as poorly bioavailable and relatively non-toxic. In this work, the effects and bioaccumulation of Cr(III), Cr(VI) and their mixture were studied using the freshwater clam Corbicula fluminea as a model organism. Mixture exposures were carried out using solutions isotopically enriched in 50Cr(III) or 53Cr(VI), allowing to quantify the contribution of each redox form to total Cr accumulation in the clams. Following exposure to individual redox forms, Cr(III) accumulated preferentially in the digestive glands and Cr(VI) in the gills of C. fluminea. In mixture exposures, both redox forms accumulated mainly in the gills; the concentration of Cr(III) in the digestive glands being much lowered compared with individual exposures. Both oxidation states affected the expression of biomarkers related to energy reserves, cellular damage and mitochondrial functioning, as well as the expression of mRNA for detoxification genes. The observed effects differed between gills and digestive glands. The present study suggests that Cr(III) is a bioavailable and biologically active elemental species deserving more consideration by the ecotoxicological community