Assessment of the global toxicity of marine sediments from the Dakar peninsula (Senegal, West Africa)

Abstract

Marine pollution in West Africa is major threat particularly around coastal megacities. We assess the chemical and ecotoxicological quality of the marine sediments in various submerged sampling sites of Dakar. Analysis revealed that sediments were slightly basic in which fine and coarse sands predominated. High percentages of total organic carbon were found sometime above6%. Higher levels of heavy metal were reported than in previous studies. Chromium and nickel were above the Probable Effect Concentration. Low trophic level appeared not affected by the overall toxicity, while medium trophiclevel was more affected. Indeed, the vast majority (91%) of sites studied revealed a net percentage of Magallana gigas embryolarval developmental abnormality over 20%. The assessment of the global toxicity of marine sediments from the Dakar sites Studied(n = 11) seemed, almost, as a whole, to be in a poor ecotoxicological state calling to take measures to improve the sanitary condition of this marine feature.