ASSESSMENT OF COPPER, IRON, LEAD AND MERCURY AND THEIR EFFECT ON Clarias gariepinus IN THOMASS DAM, DANBATTA, KANO STATE NIGERIA

This study was carried out between March and December, 2019 to assess heavy metal concentration in water, fish tissue, and their effect on water quality in Thomas Dam was assessed, samples collected from the selected stations were analyzed. Heavy metals in water showed that Iron concentration ranges between 0.03 and 0.45mg/l , Lead concentration ranges between 0.01 and 0.18mg/l and Mercury ranges from 0.07 and 0.20mg/l all the values exceeds the WHO (2011) of 0.03mg/l, 0.01mg/l and 0.002mg/l respectively, however copper concentration ranges between 0.02 and 0.33mg/l which is below the recommended limits of 2.0mg/l set by WHO (2011) for drinking water.The findings on heavy metals in the gill of fish showed that Iron concentration ranges between 0.05and 0.10mg/kg. Lead concentration ranges between 0.008 and 0.09mg/kg while Mercury concentration ranges between 0.001and 0.09mg/kg which also exceeds the WHO (1989) recommended level of 0.03mg/kg, 0.01mg/kg and 0.002mg/kg respectively, however, Copper concentration is 0.01 to 0.11 mg/kg which is below the acceptable limits of 1.3mg/kg set by WHO (1989). The order of occurrence of heavy metals in both the water sample and that of fish gill across the sampling stations were: Fe > Hg > Pb >Cu. The study reveals that the concentration of heavy metal in water and in the fish gill were influenced by the source of water, geographical patterns of the site, Irrigation, grazing by animals and burning of wastes. Hence, adequate sensitization to educate households and farmers bordering the Lake on the danger associated with loading of the Lake with waste.