Etude de la concentration des métaux traces chez Hexaplex trunculus (Muricidae) le long du littoral Tunisien

Abstract

Tunisian coast line is the important ecosystem for fisheries. The industrial activities have often an impact on the quality of marine environment. The present work is devoted to study the bioaccumulation levels of cadmium, lead and mercury in whole body of Gastropod shellfish Hexaplex trunculus and to evaluate metallic pollution levels of marine and lagoon ecosystems and finally to conclude if the specie was considered a bioindicator of environmental chemical contamination. The samples were collected in Gabes and Tunis gulfs and in Tunis and Bizerte lagoons, during years 2003/2004. The analysis methods used for trace metals determination is the method adopted by UNEP/IAEA/FAO, (1990). The obtained results show Cd, Pb and Hg levels were site and season dependant. The results showed variations from 0,227 to 0,953 mg/Kg wet weight (WW) for Cd, 0,214 to 0,786 mg/Kg WW for Pb and 0,067 to 0,595 mg/Kg WW for Hg. In addition the variation of trace metals accumulation in H. trunculus is essentially due to the specie reproduction period and pollution sources. The concentrations levels of Cd, Pb and Hg remain lower than the thresholds recommended by the World Organization of Health (WHO).