Determination of concentration of heavy metals in fish from sea port of Zanzibar by energy dispersive x-ray fluorescence (EDXRF)

Abstract

Seafood is the major source of food for a large number of people residing in the coastal areas of Zanzibar. It has been reported that the seafoods are a connecting link for the transfer of toxic heavy metals in human beings. The present study assessed the metal concentrations upon sample species of fish along the coast Sea Port of Zanzibar. Fish samples (namely changu, sardine, baracout and tuna fish) were the ideal species for the assessment study on effects of heavy metal contamination in aquatic organisms. They were collected at the Sea Port and the concentrations of the assessed metals were determined using Energy Dispersive X-ray Fluorescence (EDXRF). Concentrations of Fe, Pb, Cr, Ni, As, Cu and Zn were found to be higher in sardine whilst Hg was found to be higher in changu species.  Concentrations of Cd and Mn were found to be below the detection limits in all sample species but higher in mussels. Hg was only detected in changu species. Comparing the data from this study to data from other studies in other regions, the concentrations of Fe, Cr and As in different species of fishes collected were quite higher than the values reported in the literature. The results of this study indicated that As, Hg and Cr were higher in fish than WHO/FAO (2004)