Abhatoo - Centre Nationale de Documentation

Geochemical study of superficial sediments of Tangier bay and its continental emissaries was carried out with the aim of evaluating the contamination degree of the sediments by heavy metals and their impact on the coastal marine environmental. In Tangier bay, two sectors are distinguished: the Eastern one, with prevalence of sandy facies, and the western sector characterized by fine sediments and rich in organic carbon. The carbonates are localized to offshore of the bay. In the continental emissaries, the granulometrics facies distribution shows an increasing grain evolution from downstream to upstream. The carbonates and organic carbon show a slightly increasing enrichment from the upstream to the downstream of the emissary.
The results of the geochemical analyses show that the high contents of heavy metals are located in thewestern sector of the bay, in front of the Souani and Mghogha rivers mouths and on the downstream part of the continental emissaries. The high variations of the metals contents reveal the existence of anthropogenic origin pollution, in direct relation with the domestic and industrial liquid and solid discharges. The results of the statistical data show in the bay the presence of heavy metal association constituted by Pb>Zn>Cu>Cd>Ni, while in the continental emissaries, the dominant association is represented by Pb>Cu>Sable>Ni>Cr. These two metallic associations testify an increasing gradient of sediments pollution and the anthropic degree of the studied zone. On the socio-economic level, these data will contribute to a better management of the protection of coastal marine environment as well as the economic and tourist development of the Tangier region.