SEASONAL METAL POLLUTION LEVEL AND ECOLOGICAL RISKS OF THE SUPERFICIAL SEDIMENTS FROM A TROPICAL LAGOON AREA

The aim of this study was to the assessment of the seasonal level metal contamination of the superficial sediments from the lagoon area II and to deduce the likely seasonal ecological risks which results. This study were conducted during one year (from June 2020 to May 2021) and the concentration in eight trace metals (As, Cd, Cr, Cu, Hg, Pb, Ni and, Zn) of these substrates, obtained in this period, were used. Seven metal contamination indexes, six ecological risks indexes and, two sediment qualities guidelines were used for this purpose. The results highlighted the very severe contamination of these superficial sediments in all season by all these trace metals in the whole, especially by As, Cd and Hg. So, the seasonal ecological risks for its fauna, particularly for its benthic fauna, were very severe. The population of its benthic fauna threatened by this pollution was relatively important, to 21% in this period.