Study on Concentration of some Heavy Metals in Nile Tilapia, Oreochromis niloticus and Cat Fish, Clarias gariepinus from Lake Manzala, Egypt

Abstract

The increasing demand for fish, driven by its high nutritional value, is challenged by heavy metal pollution in aquatic environments from urbanization and industrial activities. This study examines the accumulation of heavy metals (Cu, Zn, Pb, Cd, Hg) in Oreochromis niloticus (Nile tilapia) and Clarias gariepinus (African catfish) from Lake Manzala, Egypt, using Atomic Absorption Spectrophotometry. Results revealed species-specific metal accumulation patterns: O. niloticus accumulated higher levels of Zn (122.15 µg/g) and Cu (75.23 µg/g), whereas C. gariepinus showed elevated Pb (0.441 µg/g), Cd (0.235 µg/g), and Hg (0.183 µg/g) concentrations. Liver tissues consistently exhibited the highest metal concentrations, followed by gills, gonads, and muscles. The metal levels in fish muscles were below FAO/WHO legal limits, indicating their safety for human consumption. These findings highlight the importance of species-specific assessments and ongoing monitoring to understand environmental contamination and ensure food safety. Further research into the mechanisms of metal accumulation and their ecological and health impacts is essential.