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Abstract

This research studied heavy metal variations in organs of Clarias gariepinus and Tilapia dageti from landing sites by lower Benue River at Ibi, Taraba State, Nigeria. The results of heavy metal variations examined showed C. gariepinus recorded higher concentrations of the metals compare to T. dageti. Among the metals studied zinc (Zn) values were higher for both species while cadmium (Cd) values were lower. Ranking profile in organs was: liver >Gills > muscles with metal in order of Zn > Pb > Cu > Cd. Concentration of metals varied significantly (p<0.05) in organs for T. dageti. Zinc (Zn) recorded higher concentration (1.2000 mg/kg) while cadmium recorded lower values (0.0034 mg/kg). Also the correlation results during the study for the two species showed C. gariepinus have a strong association with the heavy metals compare to T. dageti. The Correlation association of heavy metals for cadmium (Cd) showed there was significant difference (p<0.05) for affinity for metal between the species. However, Lead (Pb) concentrations showed weak correlation between C. gariepinus and T. dageti during the study period. The correlation results also showed significant difference (p<0.05) in zinc (Zn) concentrations for C. gariepinus compare to T. dageti. Results of this study ascertained occurrence of heavy metals in lower river Benue and that variations in levels affect fish. All metals studied were within safe range for fish and fisheries product by the Food and Agricultural Organization (FAO)/World Health Organization (WHO) in the two species. However continuous monitoring and check on fish species for heavy metals load should be encourage and sustained. Heavy metals concentrations should also be investigated in other commercial species of the river to assess their safety for consumption and routine studies of the river water should also be sustained.