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Title

Photo-transformation of pedogenic humic acid and consequences for Cd(II), Cu(II) and Pb(II) speciation and bioavailability to green microalga

Authors
Adenmatten, David
Miéville, Pascal
Traber, Jacqueline
Published in Chemosphere. 2015, vol. 138, p. 908-915
Abstract Humic substances (HS) play key role in toxic metal binding and protecting aquatic microorganisms from metal-induced stress. Any environmental changes that could alter HS concentration and reactivity can be expected to modify metal complexation and thus affect metal speciation and bioavailability to microalgae. The present study explores the influence of increased solar irradiance on the chemical structures and molecular weight of Elliott soil humic acid (EHA) and the associated consequences for Cd(II), Cu(II) and Pb(II) complexation and intracellular metal content in microalga. The results demonstrate that high radiance doses induce an oxidation of EHA with a formation of low molecular weight acids, an increase of –OH and –COOH group abundance, and a drop in EHA hydrodynamic size and molecular weight. The photo-induced structural changes are accompanied with a release of metal from M–EHA complexes and narrowing their size distribution, which in turn results in an increase of the intracellular Cd, Cu and Pb contents in microalga Chlamydomonas reinhardtii in agreement with the measured free metal ions concentrations.
Keywords Dissolved organic matterMetal bioavailabilityPhotooxidationFlow field-flow fractionationUVChlamydomonas reinhardtii
Identifiers
Full text
Structures
Research groups Environmental Biogeochemistry and Ecotoxicology
ISE Eau
Project FNS: 200021-134627
Citation
(ISO format)
WORMS, Isabelle et al. Photo-transformation of pedogenic humic acid and consequences for Cd(II), Cu(II) and Pb(II) speciation and bioavailability to green microalga. In: Chemosphere, 2015, vol. 138, p. 908-915. https://archive-ouverte.unige.ch/unige:72925

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Deposited on : 2015-06-02

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