Environmental and physiological impacts of heavy metals on Nile tilapia (Oreochromis niloticus)

The present study was conducted to investigate the distribution of selected metals (Fe, Zn, Cd, Pb, and Cu) in tissues of Nile Tilapia (Oreochromis niloticus) grown along El- Khadrawia drain – Mubark industrial Zone. The tissues analyzed included muscle and liver. Results showed metal concentrations in water followed a richness of: Fe> Zn> Cu> Pb >Cd mg/l (p < 0.05) while Fe> Cu > Zn > Pb > Cd mg/Kg dry wt. (p < 0.05) in muscles and liver tissues in winter season. Metal levels in muscles follow the level: Zn>Fe>Cu> Pb>Cd mg/Kg dry wt. (p < 0.05), while in liver they follow the level: Fe > Zn > Cu>Pb>Cd mg/Kg dry wt. (p < 0.05) in summer season. The presence of heavy metals led to significant decrease in nucleic acids (DNA & RNA) contents in liver tissue during summer season (p<0.05). So, the study showed that muscles of Nile Tilapia (Oreochromis niloticus) along El- Khadrawia drain are not safe from contamination with the metals investigated.