Assessment of heavy metal levels in fishes and fresh water from lake Victoria basin, Uganda.

Abstract

Background: Heavy metals -vital group of chemical contaminants and the major vehicle for entry in to the body systems is food, one of which is consumable fish. Therefore, the main purpose of this study was to assess the amount of heavy metals (Lead, Cadmium, Zinc) and their safety in fish species and fresh water in Lake Victoria basin, Uganda. Methods: This was purely a quantitative study cross-sectional study in which fish samples were collected from the selected fishing communities. Four fish species (Haplochromine cichlid, Lates niloticus, Oreochromis niloticus, clarius batruchus) were collected nine from each fish landing site was bought from skilled fishermen with whom appointments were made the previous day. Analysis against lead (Pb), zinc (Zn) and cadmium (Cd) using an atomic absorption spectrometry. Safety was assessed by making comparisons against the World Health Organization (WHO), European Union (EU) and the United States Environmental Protection Agency (US EPA) acceptable limits in fish and water. Results; Enkejje fish had the highest Zn concentrations of 25.2ppm while the other fish species all had low Zn concentrations. No significant differences were found in Pb concentrations in all fish species, although Catfish had high relative values of Pb. Concentrations of Cd were also the same in all fish species although Enkejje had relatively higher Cd concentrations than all fish species. Zn was higher in waters in Gaba and Masese while Pb was only identified in water collected from Kasenyi fish landing site in Lake Victoria.Cd was not detected. Conclusion: Fish in Lake Victoria basin, Uganda are able to bioaccumulate heavy metals even above the set limits of WHO, EU and USEPA. The main public health risks identified in the study were the presence of high relative values Pb and Cd in Catfish, Nile Tilapia and Nile perch.Zinc was found to be a good source in small fsh which is enkejje.