Trace metals in liver and kidney of the franciscana (Pontoporia blainvillei) from the northern coast of Rio de Janeiro State, Brazil

In the Southwestern Atlantic few studies have documented trace metal concentrations in cetacean tissues. This study presents both hepatic and renal trace metal concentrations (Fe, Cu, Zn, Mn, Hg and Cd), in franciscana (n=17), inhabiting the waters of Rio de Janeiro State, southeastern Brazil. The concentrations of Fe, Cu, Zn, Mn and Hg generally were highest in the liver and Cd levels in liver and kidney were comparable. Hepatic and renal essential metal (Fe, Cu, Zn and Mn) concentrations were similar to those documented elsewhere for other species. THg and Cd concentrations were found to increase with age. The low concentrations of trace metals determined in the franciscana tissues in this study reflect its dietary habits, trophic position and the low bioavailability of metals in northern Rio de Janeiro