Assessment of trace elements in surface sediments from Hammamet Gulf, Tunisia (Mediterranean sea)

Abstract

Metals in sediment constitute a significant source of environmental pollution. Trace metals and oligo-elements in surface sediments from Hammamet gulf( Tunisia) were assessed in order to evaluate their levels and spatial distribution due to urbanization, economic and touristic development of this region. Twenty stations were prospected and the collected sediment samples were analyzed by Atomic Absorption Spectrophotometry. The ranges of the measured concentrations in  the sediments  were as follows: 0.19-1.86 mg.kg-1 for Cd, 47.6-150.2 mg.kg-1 for Pb, 0.23-0.46 mg.kg-1 for Hg, 1.80-30.42 mg.kg-1 for Cu, 287-713 mgkg-1 for Zn, 3-26 gkg-1 for Fe, 86-374 mgkg-1 for Mn, 11-18 gkg-1 for Mg, 61-160 g.kg-1 for Na, 8-109 g.kg-1 for Ca, 4-19 g.kg-1 for K. The results showed significant correlation between Cu, Pb and Zn, indicating that they have common anthropogenic and natural sources. The spatial distribution of metals in sediments of Hammamet Gulf   shows that the level of metals in the central and South Eastern parts of  the Gulf is relatively high by some metals (i.e. Pb, Zn). This contamination is depending mainly on anthropogenic sources and petrochemical activities. Concentrations of trace metals in the studied area was comparable to the levels recorded in different other Mediterranean ecosystems. A constant monitoring should be conducted since the level of heavy metals may increase as industries are established in Hammamet Gulf.