Variations in the geographical distribution,size and content of cadmium in the mussel Mytilus galloprovincialis collected at the coast of Safi [Variations de la répartition géographique,taille et teneur en cadmium chez la moule Mytilus galloprovincialis prélevée au niveau du littoral de Safi]

The aim of this study is to assess the degree of contamination of the marine ecosystem of coastal safi (morocco),using the mussel mytilus galloprovincialis as a bioindicator of pollution. the main objective is the correlation between the distance to the sources of pollution,the size distribution of mussels and their levels of cadmium as a model. five sites (s) coasts sampling is chosen: s1 cap beddouza,s2 marissa iii,s3 located 5 km south of safi,the discharges are mainly minerals,s4 ouled salman located 16 km south of safi,characterized by the absence of any domestic activity the industrial and s5 located 36 km south of safi at souiria lakdima remote from industrial activity. the distribution and size of the mussel vary from one site to another. the site of cap beddouza,taken as a reference and having good environmental conditions,holds the biggest of the five mussel study sites followed by the station souiria lakdima. these results demonstrate that the size of the mussels of the same age and high in different sites,varied according to the quality of the marine environment. the study of the geographic distribution of mussels contaminated by cadmium shows that the s3 site has the highest concentration of 29.2 (mg/kg dry matter). this site is located close to the main outlet of the chemical,which confirms the anthropogenic source of cadmium. more away from the addition site s3 content becomes lower. indicating that the cadmium discharged at this site,is transported by the ocean current as to more distant site (s1) sites (s2),(s4) and (s5) with a concentration of 4.68,9.16,5.86 and 5.5 mg/l respectively.