Seasonal distribution of cadmium, lead, nickel, and magnesium in several tissues of mussels from the Algerian coasts

This study aims to investigate the distribution of heavy metals (Cd, Pb, Ni, and Mn) in different organs of two marine mussel species, Perna perna collected from Figuier site and Mytilus galloprovincialis sampled from Sercouf and Algiers port sites of the Algerian coast. Thirty individuals (>5 cm length) were seasonally sampled over a 1-year period from each site, and condition index (CI) and gonado somatic index (GSI) of mussels were calculated. The gill, digestive gland, rest of soft tissues, and gonad were accurately isolated and heavy metal contents were analyzed by ICP-MS. Heavy metal results, expressed on mu g/g dry weight, ranged from 0.1 to 2.6 Cd, 0.1 to 17.15 Pb, 0.36 to 25.7 Ni, and 3.68 to 74.76 Mn. Thus, typical distribution of studied metals in various organs of mussels was found. In fact, the digestive gland followed by gill revealed significantly high metal concentrations. However, gonad showed low heavy metal contents. Different patterns of heavy metal distribution in various organs of mussels were found at the three sampling sites. High levels of Cd, Pb, Ni, and Mn were detected in mussels of Sercouf, Algiers port, and Figuier sites, respectively. According to the Algerian and European norms, mussels collected from all sites were healthy except those of Algiers port sampled in autumn and winter seasons where lead contamination was found.