Multimetal interactions between Cd, Cu, Ni, Pb, and Zn uptake from water in the zebrafish Danio rerio

The uptake of essential (Cu, Ni, and Zn) and nonessential (Cd and Pb) metals in the gills and whole body of zebrafish exposed to a mixture of trace elements at environmentally relevant concentrations was investigated using a stable isotope technique. Negative and positive interactions as well as nonlinear responses were observed. The Cd and Pb uptake processes were influenced the most by other metals. The uptake of Cd was inhibited by Cu, Pb, and Zn and enhanced in the presence of Ni at concentrations above 0.1 microM. Pb uptake rates were consistently increasing in the presence of Cd, Ni, and Zn in both gills and the whole body, except in one case of decreased whole body Pb uptake in the presence of Cd. The addition of Cu resulted in more complex nonlinear variations in Pb uptake rates. The addition of Pb, in turn, facilitated Cu uptake with a more pronounced effect in the gills, while Zn had a stimulating effect on the whole body level. Uptake of Ni continuously decreased with the addition of Zn, and some decline in whole body Ni accumulation was observed in the presence of Cd. In contrast Cu increased the Ni uptake rates in both gills and the whole body. The results demonstrate the complexity of the uptake processes occurring in media containing a mixture of metals at environmentally relevant concentrations. These interactions may be of key significance in understanding and predicting metal uptake, accumulation, and toxicity in multimetal exposure scenarios.