Spatial and Tissue-Specific Accumulation of Heavy Metals in Tilapia (Oreochromis niloticus) Fish from Nguru River

The concentration of heavy metals namely, Lead, Arsenic, chromium, copper and Zinc (Pb, As, Cr, Cu, Zn) were determined in Tilapia fish samples collected from three (3) selected areas of Nguru River during raining season. The fishes were carefully dissected and the muscles, livers and gills were sampled and prepared for digestion, afterward the level of heavy metals were assessed using atomic absorption spectroscopy (AAS). The results showed that all metals identified in this study follow the same accumulation pattern, with liver having the highest concentration (As:11681µg/kg, Cu:36.87µg/kg, Cr:252.50µg/kg, Zn:11688.11µg/kg), followed by gills (As:543.39µg/kg, Cu:16.04µg/kg, Cr:499.44µg/kg, Zn:9438.93µg/kg), and muscles (As:479.58µg/kg, Cu:14.29µg/kg, Cr:252.50µg/kg, Zn:7233µg/kg). Lead was not detected in all the tissue samples. However, the concentrations of heavy metals in the muscles of fishes collected from all the sites were within the permissible levels and are safe for the human consumption and public health.