Heavy Metals Concentrations in some selected Fish Species in Tono Irrigation Reservoir in Navrongo, Ghana

Abstract

An assessment of heavy metals (lead, cadmium, copper, manganese, zinc and iron) in water, sediments and in the organs of Tilapia (Sarotherodon gallelacus) and African Giraffe Bagrid (Auchenoglanis occidestalis) from the Tono irrigation dam has been carried out. Sediments contained the highest concentrations and appeared to be the major source of bioaccumulation of heavy metals in the fish species as deduced from estimated transfer factors. The mean concentrations of heavy metals Cd, Zn and Cu in muscle and gills both fish species fell within USEPA (2002) acceptable levels for human uses while those of Pb, Mn and Fe were above. The mean concentrations of heavy metals in raw water fell within the permissible limits of WPCL (2004) for aquaculture except Cd (0.03mg/l) and Fe (0.86mg/l). The relatively high mean concentrations of Pb (0.375mg/kg FW in the two fish species may originate from chemicals (fertilisers, weedicides and pesticides) being used for agricultural purposes in the study area. This is a potential health hazard and requires monitoring and awareness creation.

Keywords: fish species, Ghana, heavy metals, Navrongo, Tono dam,