No abstract

Studies have shown that elevated heavy metal concentrations in water and sediments may be biomagnified along the aquatic food chains/webs and eventually affecting human health through the consumption of metal-contaminated water and/or fish from such water bodies. This study was conducted to assess the concentration of heavy metals in the tissues of Oreochromis niloticus baringoensis, Protopterus aethiopicus and Clarias gariepinus fish species of Lake Baringo and compare the results with WHO guideline values. Water and fish samples were collected from five selected sites in six sampling occasions and the analyses for heavy metals (i.e. Cu, Hg, Cd, Pb) in fish and water samples was done using the Atomic Absorption Spectrophotometer at Nakuru Water and Sewerage Company Laboratory. Most of the heavy metals of interest were available in measurable quantities in water and fish samples that were analyzed. There was a significant difference in Cadmium, Copper and Mercury concentration in water samples collected from different sampling sites in Lake Baringo (p>0.05). A negative relationship was observed between pH and heavy metals with sampling sites having low water pH recording high heavy metal concentrations. The pooled heavy metal concentration levels recorded in fish for Copper, Cadmium and Zinc was 0.4728±0.12455, 3.565±0.06289 and 24.398±3.26165 respectively. Therefore the heavy metal concentration in fish decreased in the sequence Zinc>Cadmium>copper. Lead and Mercury concentrations were below the limits of instrument detection. Most of the metals in fish were below WHO guideline values thus posing more of environmental than human health concern except for cadmium. There is a need to carry out continuous monitoring of metal contaminants in Lake Baringo. Such an assessment will be vital in understanding human health risks associated with heavy metal exposure through consumption of metal-contaminated fish.