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Rate of Cd2+ Release from Dissolved Fulvic Acid and Natural Dissolved Organic Carbon as a Function of UVB Dose.

Néron, Roxanne; Auclair, Jean-Christian; Fortin, Claude (2006). Rate of Cd2+ Release from Dissolved Fulvic Acid and Natural Dissolved Organic Carbon as a Function of UVB Dose. Environmental Chemistry , vol. 3 , nº 6. p. 433. DOI: 10.1071/EN06053.

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Résumé

Abstract. Using controlled UVB exposures in a laboratory incubator, the photolytic release of bound cadmium from cadmium-contaminated dissolved fulvic acid and cadmium-amended natural lakewater dissolved organic carbon was examined using an ion-exchange technique, developed to measure the cadmium free-ion concentration (Cd2+). In the fulvic acid experiments, with increasing UVB dose, the increasing cadmium free-ion concentration followed an exponential saturation function, whereas the decrease in dissolved organic carbon was linear. Experiments using natural lakewaters did not reveal any increase in Cd2+, even at high UVB exposures. Given the much greater dissolved iron concentration in humic natural lakewaters, relative to the fulvic acid medium, iron photoreduction and reoxidation produces fresh amorphous iron oxide surfaces. We hypothesize that these bind the cadmium free-ion, thus reducing its aqueous concentration. Depending on Cd2+ affinity to biological surfaces, this mechanism might thus competitively further protect the biota from trace metal toxicity.

Type de document: Article
Mots-clés libres: bound residues; complexation; dissolved organic carbon; humic substances; UV radiation
Centre: Centre Eau Terre Environnement
Date de dépôt: 08 janv. 2021 16:52
Dernière modification: 08 janv. 2021 16:52
URI: http://espace.inrs.ca/id/eprint/10943

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