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Characterizing dissolved Cu and Cd uptake in terms of the biotic ligand and biodynamics using enriched stable isotopes

Environmental Science and Technology

By:
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DOI: 10.1021/es0615122

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Abstract

The biotic ligand model considers the biological and geochemical complexities that affect metal exposure. It relates toxicity to the fraction of physiological active sites impacted by reactive metal species. The biodynamic model is a complementary construct that predicts bioaccumulation and assumes that toxicity occurs when influx rates exceed rates of loss and detoxification. In this paper we presume that metal influx rates are mechanistically the resulting processes that characterize transmembrane transport. We use enriched stable isotopes to characterize, both in terms of the biotic ligand and biodynamics, dissolved metal uptake by a freshwater snail at water hardness varying up to 180-fold. Upon 24 h exposure, metal uptake was linear over a range encompassing most environmental concentrations; although saturation kinetics were observed at higher concentrations. Cadmium influx rates correlate with changes in the affinity of the biotic ligand, whereas those of Cu correlate with changes in both site affinity and capacity. A relationship between metal influx rate and ligand character asks whether toxicity is the result of accumulation at the biotic ligand or the rate at which metal is transported by that ligand.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Characterizing dissolved Cu and Cd uptake in terms of the biotic ligand and biodynamics using enriched stable isotopes
Series title:
Environmental Science and Technology
DOI:
10.1021/es0615122
Volume
41
Issue:
9
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
3140
Last page:
3145
Number of Pages:
6