Effects of Na, Ca, and pH on the simultaneous uptake of Cd, Cu, Ni, Pb, and Zn in the zebrafish Danio rerio: a stable isotope experiment.
Concentrations of major cations in the medium play an important role in metal accumulation process. Variations in Ca, Na concentrations and pH of the medium had pronounced effects on metal uptake in zebrafish simultaneously exposed to five metals at environmentally realistic concentrations. Largest effects were found in gills (the whole body for Ni). A high level of Zn homeostatic regulation was observed. Addition of 0.1-2.5 mM Ca2+ to the medium had a suppressing effect on Cd uptake. The highest Cu, Pb and the lowest Ni uptake rates were observed atthe middle 0.5 mM Ca concentration. Increase in Na concentrations from 0.5 to 8 mM decreased Cd and increased Ni uptake rates in gills. Both low and high Na concentrations in water had a suppressing effect on Pb uptake. Increase in the pH of the medium promoted Cd and Ni uptakes. Cu and Pb, in turn, exhibited highest uptakes at neutral conditions compared to acidic and alkaline pH due to changes in Cu and Pb speciation. The fact that such changes in metal uptakes occur at low, environmentally relevant concentrations, emphasizes the need for further studies of bioaccumulation and toxicity processes.
Komjarova
Irina
I
Department of Biology, University of Antwerp, Antwerp, Belgium. Irina.Komjarova@ua.ac.be
Blust
Ronny
R
D000818:Animals; D002118:Calcium; D006863:Hydrogen-Ion Concentration; D007554:Isotopes; D019216:Metals, Heavy / Q000493:pharmacokinetics*; D012964:Sodium; D014867:Water / Q000737:chemistry*; D015027:Zebrafish / Q000378:metabolism*
D007554:Isotopes; D019216:Metals, Heavy; D014867:Water; D012964:Sodium; D002118:Calcium