Bioaccumulation rate of Cd and Pb in Mytilus galloprovincialis foot and gills

Abstract

Abstract The aim of this experimental study was to investigate the bioaccumulation rate of cadmium and lead in the mussel foot and gills and the possibility to use these organs as quantitative bioindicators of the pollution of near-shore marine environments. Therefore, our experiment has been designed to provide conditions as close as possible to those found in nature. Three age groups of the mussel Mytilus galloprovincialis (1, 1.5 and 2 yr) were kept in tanks with elevated cadmium and lead concentrations (Cd, 5.1, 9.6 and 13.9 nM; Pb, 5.2, 9.9, 14.7 nM) for seven days. To study the interaction effects of Cd and Pb during accumulation, the mussels were also exposed to a mixture of these metals with concentrations of 9.5 nM Cd and 5.1 nM Pb. Even though the concentrations of metals in the experimental medium were relatively low, compared with the concentrations used by other authors in similar experiments, a significant increase of Cd and Pb concentrations in foot and especially in gills, as a function of time, was observed (particularly in younger age groups). This study also confirms the fact that Cd and Pb concentrations in mussel foot and gills depend on their size and age as well as on the metal levels in a particular environment and on the exposure time to elevated metal concentrations in the experimental media. In addition, the mussels in the tanks with higher metal concentrations accumulated greater metal quantities. It is interesting that metal accumulation in foot and gills during the experiment (seven days) showed slight exponential increase. Interactions between Cd and Pb were not observed with reference to bioaccumulation. Apart from known comparative advantages with respect to other organs (invariability of weight with reproductive cycle, easy removal from the rest of the soft tissue), this study confirms the assumption that the mussel foot and gills may be used as quantitative bioindicators for assessing the degree of cadmium and lead pollution in a particular marine environment.