Bioaccumulation of Some Heavy Metals in Tissues of The African Cat-Fish Clarias gariepinus From Selected Markets in Delta State, Nigeria

ABSTRACT

The increasing rate of consumption of the common African catfish, Clarias gariepinus, a popular delicacy in Delta State, Nigeria has raised worries about the safety of health of consumers in the face of perceived increasing input of recalcitrant pollutants such as the heavy metals in the aquatic habitats of the organism. This research therefore investigated the bioaccumulation of some heavy metals (Pb, Cd, Cu, Zn, Co) in the muscle and brain tissues of the catfish, C. gariepinus sourced from markets in Delta State. Replicate adult fish samples were obtained from seven market locations in Oleh, Asaba, Ekpan, Ogwashi-Ukwu, Okere, Abraka and Ughelli towns, labeled and taken to the laboratory in iced coolers. The presence and levels of the heavy metals were determined with the Varian Spectra 600 AA atomic absorption spectrophotometer. The descriptive statistics, Student’s t-test, single factor ANOVA, as well as means and variation plots were used to analyze data. Of the heavy metals, only Zn was detected with variations ranging from 0.015-0.19 (0.09 ± 0.02) mg/kg in the muscle and 0.035-0.36 (0.16 ± 0.03) mg/kg in the brain tissues. Accumulation levels showed significant difference (Sig. t=0.005) and correlation (Sig. r=0.000) between the muscle and brain tissues at pFcrit(4.02)] at p