Metal Distribution and Bioaccumulation in Water and Fish of a Tropical Lake

Abstract

A study was conducted to investigate the metal (copper, zinc and manganese) concentrations in the surface water and fish of a man-made lake receiving agricultural and domestic effluents in Ibadan, Nigeria. The lake (Main Lake, IITA) is a site of drinking water abstraction and the major water source for the surrounding agricultural research farms. Factor analysis indicated that copper was an important contributor to the total variance observed in the lake, being involved in Factor 1 of the 6-factor model. Significant differences occurred in the copper and manganese levels of the organs of Oreochromis niloticus at P< 0.05 and P< 0.01 respectively and in manganese levels of Sarotherodon. galilaeus at P< 0.05. Significant differences did not occur in Lates niloticus and Synodontis nigrita organs. Bioaccumulation factors from water to fish muscles were highest for manganese ranging from 4.56-10.56; zinc from 1.83-5.67 and copper from 1-1.8. These factors showed that despite the low levels of these metals in surface water, there may be an onset of bioaccumulation in some of the fishes. This work contributes to the baseline data on the presence and effects of metals in African freshwaters and could aid future plans for the control of toxic build-up in our aquatic environments.

Keywords: Metal, concentrations, lake, bioaccumulation, water, fish and IITA

Tropical Freshwater Biology Vol. 17 (1) 2008: pp. 81-91