Bioaccumulation of copper, lead and zinc in the organs and tissue of Clarias gariepinus (Burchell 1822) in Eleyele Lake, Ibadan, Nigeria.

Abstract

Bioaccumulation of copper (Cu), lead (Pb) and Zinc (Zn) in the intestine, gill and muscle of Clarias gariepinus in Eleyele Lake, Ibadan, Nigeria was investigated between February and July 2002. Samples of C. gariepinus were taken monthly from the fishermen's catches. These samples were analysed for Cu, Pb and Zn. Water samples were also collected twice during both dry season (February – April) and wet season (May – July) for heavy metal analysis.


Results obtained showed that the rate of accumulation of these heavy metals varied among the tissue and organs examined. The prime site for Zn and Cu absorption in C. gariepinus is the intestine with mean levels of 84.58 + 23.21mg/kg and 12.09 + 3.31mg/kg recorded respectively. Pb was only detectable in the gill of C. gariepinus with mean Pb concentration of 8.67 + 9.63mg/kg. In all the samples examined, the muscle recorded the lowest level of heavy metals. Seasonal variation of these heavy metals (mg/kg) in C. gariepinus shows that wet season has the highest value of 4.11+ 8.19mg/kg for lead, 6.37 + 4.36mg/kg (copper) and 57.46 + 34.09mg/kg (Zinc) compared to 1.67 + 5.0mg/kg (Lead), 6.01 + 5.82mg/kg (copper) and 65.07 + 32.42 (Zinc) for dry season. These values however showed no significant difference.


Key Words: Bioaccumulation, organs and tissue, Clarias gariepinus.


Journal of Environmental Extension Vol.4 2003: 74-78