Bioaccumulation of trace elements by Loricariidae (Teleostei: Siluriformes) in Brazilian Savanna streams

Trace elements are present in small concentrations in nature, but have a high potential for contamination and toxicity in aquatic environments. Although they occur naturally, the intensity of human actions increases the contamination of these environments. In this study, we evaluated the bioaccumulation of zinc (Zn) and cadmium (Cd) in Loricariidae species in streams of the Brazilian Cerrado. Trace elements were quantified in the muscle and liver tissues of different Loricariidae species by atomic absorption spectrometry. In addition, limnological variables and the concentrations of Zn and Cd in the water of the studied streams were measured. We collected 40 individuals belonging to six Loricariidae species. Zn concentrations in the water were higher than Cd concentrations. Zn and Cd were bioaccumulated by all Loricariidae species. Liver tissue accumulated higher concentrations of Zn, while Cd was accumulated in greater quantities in muscle tissue. The concentrations of trace elements accumulated by fish were related to some limnological variables, but especially to the concentrations of Zn and Cd dissolved in the water. The presence of Zn and Cd in the environment and in animals may indicate potential contamination for other communities that use water resources, especially those at higher trophic levels, i.e. humans.