Répartition du mercure dans les sédiments de surface de l’oued Meliane et de la frange littorale Rades - Hammam lif, golfe de Tunis (Tunisie)

Abstract

The Rades - Hammam lif coast is a highly urbanized and industrialized area exposed for a long time to the contamination by pollutants coming essentially from the Meliane River which constitutes the main source of trace metals.Mercury is an element known for his toxicity, it is found naturally on earth and also in the environment due to intense human activities. The Gulf of Tunis is influenced by the contributions of the main exoreic rivers, coming from various sources of domestic, industrial and agricultural discharges. The southwestern part of the Gulf of Tunis, in particular the Rades - Hammam lif coastal fringe, has for years been subjected to the influx of discharges from the oued Meliane. The mercury concentration at the level of the oued Meliane ranges from 0.02 to 0.61 (µg.g-1) and from 0.01 to 0.97 (µg.g-1) respectively during the summer season and winter. The enrichment factor indicates moderate to extremely high enrichment where the pollution is of anthropogenic origin. The contamination factor shows considerable to very strong contamination at the level of the Meliane oued and the coastal stations. The spatio-temporal distribution of Hg varies according to the sources of releases installed on the coastal zone and on the edge of the oued Meliane as well as the direction of the littoral drift at the level of the coast.