Assessment of seasonal variations of some heavy metals in the gills and muscles of some nile tilapia from some dams in Katsina state, Nigeria.

Aim/Background:The growing concern about human health risk associated with consumption fish from polluted sources has highlighted the importance of monitoring heavy metal levels in tilapia tissues. Hence this study determined the levels of some heavy metals (Cadmium. Cobalt, Copper, Nickel, Lead and Zinc) in the muscle and gill of Nile Tilapia(Oreochromis Niloticus) collected from Gwaigwaye, Maska and Zobe dams in dry and wet seasons. Method:The digested tissues were analyzed using Microwave plasma atomic emission spectrometry. Results:The results obtained ranged as follows 0.023±0.01 to 0.066±0.051 mg/kg for Cadmium, 0.00±0.00 to 0.10±0.00 mg/kg for Cobalt, 0.076±0.02 to 0.76±0.00 mg/kg for Cu, 0.013±0.03 to 0.2±0.00 mg/kg for Nickel, 0.00±0.00 to 0.13±0.03 mg/kg for Lead and 0.60±0.04 to 0.79±0.03 mg kg for Zinc in Tilapia muscles of Gwaigwaye, Maska and Zobe dams in dry and wet seasons. Likewise, the concentrations were obtained in the following ranges, 0.01±0.03 to 0.03±0.00 mg/kg for Cadmium, 0.00±0.00 to 0.086±0.03 mg/kg for Cobalt, 0.034±0.03 to 0.160±0.00 mg/kg for Copper, 0.00±0.00 to 0.166±0.03 mg/kg for Nickel, 0.00±0.00 to 0.06±0.00 mg/kg for Lead and 0.060±0.04 to 0.766±0.03 for Zinc in tilapia gill of Gwaigwaye, Maska and Zobe dams in dry and wet seasons. The levels of the heavy metals analyzed in gill and muscles of tilapia were below the permissible limits of world health organization (WHO) and Standard Organization of Nigeria (SON).The results of statistical Analysis(ANOVA)indicated no significant difference between the levels of the analyzed metals in the muscles and gills of Nile tilapia from Maska, Gwaigwaye and Zobe dams, across the dry and wet seasons as P values were greater than 0.05. Conclusion: It can be concluded that the gills and muscles of tilapia analyzed were safe for human consumption.