Concentrations of metals in liver of Guiana dolphins (Sotalia guianensis) from an estuary in Southeast of Brazil

Abstract

Concentrations of Fe, Zn, Cu, Mn, Pb, Cr, Co and Ni were measured in the liver of 21 Guiana dolphins from the Estuarine-Lagoon Complex of Iguape-Cananéia, in order to indicate the impact of their habitat and to verify if these concentrations differ between the sexes and age classes. The concentrations followed the order: Fe>Zn>Cu>Mn>Pb>Cr>Co>Ni, and with the exception of lead, all concentrations were in the same order of magnitude observed for the species. The accumulations between the sexes were similar, while copper were higher in infants, suggesting that the organ can act as a reservoir for Co in a period of rapidly postnatal growth. Lead mean concentration (3.17 μg g-1) were the highest described for the species, which from a toxicological point of view may be a matter of concern. This accumulation suggests a trophic transfer, indicating the contamination of the food chain, which possibly reflects the local environmental contamination caused by ancient lead mining.