An alternative approach to bioaccumulation assessment of methyl-Hg, total-Hg, Cd, Pb, Zn in bivalve Anomalocardia brasiliana from Rio de Janeiro bays.

We present an alternative approach for establishing in situ bioaccumulation assessment of methyl-Hg (MeHg), total-Hg, Cd, Pb and Zn in bivalve Anomalocardia brasiliana from four bays of Rio de Janeiro presenting varying degrees of eutrophication, acid volatile sulfides (2-55 μmol g-1), simultaneously extracted metals (SEM) and total metals (TM) in sediments. Using metal concentrations of composite samples from three size classes of bivalve and their incorporation rates (IR = metal concentration / total length), which depend on exposure time, we calculated asymptotic IR and respective consequent metal concentrations. Both IR and the metal concentration presented inverse relationships with total length (excepting MeHg) and bay contamination. Lead and zinc concentrations were above Brazilian legal criteria in the most anoxic and contaminated bay, suggesting significant metal bioavailability (SEM/TM between 8% and 63%).