Bioaccumulation of some heavy metals in tissues of the African catfish (clarias gariepinus) from selected markets in Delta State, Nigeria
Date
2021-06
Authors
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Publisher
Federal University of Technology, Owerri
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, OgwashiUkwu, 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 0.0150.19 (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 p<0.05. There was also significant spatial heterogeneity in accumulations of the metal [F(100.97)>Fcrit(4.02)] at p<0.05; with least accumulation of 0.03 (± 0.01) mg/kg recorded in Ughelli and maximum accumulation of 0.28 (± 0.07) mg/kg recorded in Oleh locations. However, levels were below the Food and Agricultural Organization and World
Health Organization acceptable limits for Zn in edible fish. Results revealed that the lipophilic brain tissues accumulated more heavy metal than muscle tissues. It was concluded that since accumulation levels were low, they do not currently constitute public health risks to consumers in Delta State.
Description
This thesis is for the award of Master of Technology (M.Tech.) in Environmental Management
Keywords
African catfish, heavy metals, tissue accumulation, Delta State, local delicacy, Department of Environmental Management
Citation
Iloegbunam, K. A. (2021). Bioaccumulation of some heavy metals in tissues of the African catfish (clarias gariepinus) from selected markets in Delta State, Nigeria [Unpublished Master's Thesis]. Federal University of Technology, Owerri, Nigeria