Role of biologically-mediated boundary reactions in the bioavailability of Cd to freshwater phytoplankton.

Liu, Fengjie; Fortin, Claude et Campbell, Peter G. C. (2016). Role of biologically-mediated boundary reactions in the bioavailability of Cd to freshwater phytoplankton. In: 7th SETAC World Congress / 37th Annual Meeting Society of Environmental Toxicology and Chemistry - SETAC North America 2016, 8 6-10 novembre 2016, Orlando, États-Unis.

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Résumé

We show that concentration in ambient well-buffered water, the bioavailability of dissolved Cd decreased or increased due to biologically-mediated chemical changes in the boundary layer of planktonic cells under different physiological conditions. For instance, decreased Cd bioavailability can result from a decrease in the free Cd2+ concentration in the boundary layer, resulting from deprotonation of metal-binding ligands induced by local pH enhancement as a consequence of algal release of HO. The observations of increased Cd bioavailability were probably due to an enhancement of the free Cd2+concentration in the boundary layer, resulting from chemical oxidation of metal-binding ligands (e.g., cysteine) by oxidants released by the algal cells. Note that there is no uptake of intact cysteine-Cd complexes. The results highlight the importance of biologically-mediated surface processes (e.g., redox and pH changes), in addition to other well-known abiotic processes, in determining metal bioavailability.

Type de document:	Document issu d'une conférence ou d'un atelier
Informations complémentaires:	Affiche
Mots-clés libres:	phytoplankton; biodisponibilité; écotoxicologie; algues
Centre:	Centre Eau Terre Environnement
Date de dépôt:	31 août 2017 20:48
Dernière modification:	31 août 2017 20:48
URI:	https://espace.inrs.ca/id/eprint/5243

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