Analysis of metal contamination and bioindicator potential of predatory fish species along Contas River basin in northeastern Brazil.

Samples of two carnivore fish species (Hoplias malabaricus and Serrasalmus brandtii) were collected along Contas River, northeastern Brazil, to determine the levels of Co, Cr, Cu, Fe, Mn, Ni and Pb in edible and non-edible tissues of these important local fisheries resources. Lead could not be quantified in most of the samples, while the other metals were detected in both species. In edible parts, Cr levels were above Brazilian threshold limits in all specimens and Ni was at high concentration in S. brandtii individuals from one collection site. In non-edible parts (viscera), besides Cr, Cu concentration was higher than that recommended by Brazilian laws. Both fish species proved to be sensitive to environmental contamination. Despite the different ecological characteristics, such as vagility and feeding strategy, these fish showed that aquatic predators are efficient bioindicators of water quality and biomagnification.