Nonessential elements (Al, As, Cd, & Pb) in shrimps and mussels from southeastern Brazil

Abstract

The bioaccumulation of nonessential elements (Al, As, Cd, & Pb) in shrimps and mussels from southeastern Brazil (21°S–23°S) were compared. The objective was to verify and confirm the differential responses of elemental assimilation at both the taxonomic and spatial level. Two hypotheses were predicted: i) shrimps have lower element concentrations than mussels, and ii) both shrimps and mussels from the highly polluted site have higher element concentrations. The results confirmed the first hypothesis. The intense filter feeding activity of mussels explains the taxonomic difference. The second hypothesis was not validated. Both shrimps and mussels from the highly polluted site (Guanabara Bay) have lower elemental concentrations than individuals from the less polluted site. This finding is explained by the large inputs of sewage that result in partially reducing conditions of the water and high sedimentation rates, maintaining elements buried in anoxic sediment and making them unavailable for biological uptake. To understand what drives the bioaccumulation of chemical elements in marine animals it is necessary to know the species feeding habits and physiology, and the habitat characteristics in each region.