Carcinogenic and Non-carcinogenic Risks of Heavy Metals in Clarias gariepinus (African Catfish) Obtained from Bariga Section of Lagos Lagoon, Nigeria

Document Type : Original Article


1 Department of Biology, Federal University Birnin Kebbi, PMB 1157, Birnin Kebbi, Nigeria

2 Biology Unit, Distance Learning Institute, University of Lagos, Nigeria

3 Department of Biology, National Open University of Nigeria, Lagos, Nigeria

4 Department of Applied Geophysics, Federal University Birnin Kebbi, Nigeria


The Bariga section of Lagos lagoon is famous in Lagos for fishing activities. However, the safety of edible fishes sold in the place has not been evaluated for a long time. This study determined the safety of Clarias gariepinus (African catfish), which is the most frequently patronized fish species in the area. Samples of the fish and soil sediments obtained during rainy and dry seasons were subjected to atomic absorption spectroscopy to determine the levels of cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), and manganese (Mn). Afterward, the daily intake (DI), target hazard quotient (THQ), hazard index (HI), and carcinogenic risks (CR) of the heavy metals were calculated. The results showed that the levels of Cd and Pb in the fish and soil sediments were above the world health organization (WHO) permissible limits, while Zn, Cu, and Mn were normal. The DI of the heavy metals, as well as the THQ and HI, were normal. However, the CR of Cd and Pb were above the recommended limits. The heads of the fishes contained the highest concentrations of the heavy metals, DI, THQ, HI, and CR. Among the heavy metals, Cd had the highest CR. There was no significant (p > 0.05) seasonal variation in the accumulations of the heavy metals in the soil sediments. Overall, the results showed that the fish may predispose consumers to health hazards. Consequently, there is a need for heavy metal pollution control in the lagoon, to safeguard the health of fish consumers.


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