Comparative Assessment of Heavy Metals Bioaccumulation in Tissues of African Catfish (Clarias gariepinus) Collected from Otin, Oba, Ogun and Agbabu Rivers, South-Western Nigeria

Abstract

Heavy metal contamination has devastating effects on the ecological balance of recipient water bodies and the diver- sity of aquatic organisms present therein. Fish are widely used to evaluate the health of aquatic ecosystems because pollutants build up in the food chain which results in adverse effects in the aquatic systems. African catfish (Clarias gariepinus) is of great commercial importance because it is the most widely consumed freshwater fish in Nigeria. In this research, heavy metal pollutants in the tissues of Clarias garienus collected from Otin, Oba, Ogun and Agbabu Rivers in the South-Western Nigeria were investigated to evaluate the bioaccumulation patterns of heavy metals. The fish were collected twice a month for six months from May to November. Concentrations of heavy metals were determined using Atomic Absorption Spectrophotometer (AAS). Results were compared using ANOVA and P<0.05 was considered to indicate statistical significance. Means of significant differences were separated using Duncan’s multiple range test. The study indicated that the levels of heavy metals contamination in the analyzed water bodies are in the following order: Agbabu>Ogun>Otin>Oba. The mean concentration of the heavy metals in each organ and tissue sampled differed slightly and also conformed to the specifications of regulatory bodies.