keywords: Water, soil, fish, plant, heavy metals
The aim of this study was to determine the levels of heavy metals in soil, water, plants and fish samples from Matara-Uku in Hadejia-Nguru wetlands. Twenty (20) samples of soil, water, two plants samples (Moringa oliefera and Paulliria pinnata) and six Tilapia fishes were collected from the four sites and digested using a mixture of hydrochloric acid and trioxonitrate (V) acid in the ratio 3:1. The plant samples were digested for 4 h at 900C. The heavy metals (Pb, Ni, and Cd) levels in the digested samples were analyzed using Atomic Absorption Spectrophotometer. The mean concentration of the heavy metals analyzed for the water samples ranged between 0.127 to 0.273 mg/L for Pb, 0.00260 to 0.00530 mg/L for Cd, and 0.0705 to 0.141 mg/L for Ni, respectively. The Concentration of Pb exceeded the maximum permissible limit of 0.01 mg/L for surface water. The heavy metals concentration in plants ranged between 3.0±0.026 to 14.7±0.084 mg/kg for Pb, 0.056±0.001 to 3.089±0.002 mg/kg for Cd and 1.96±0.003 to 6.87±0.005 mg/kg for Ni. The mean nickel (Ni) concentration in fish liver was 0.010633, muscle was 0.01075 mg/kg and the average nickel (Ni) concentration in gills was 0.0111 mg/kg. The mean concentration of Pb in muscles was 0.01015 mg/kg, in gills it was 0.0043 mg/kg and lead (Pb) was not detected in the liver. While cadmium, (Cd), was not detected in all fish samples. The concentrations of all heavy metals which were analyzed in the muscles, gills and liver of tilapia fish (Oreochromis niloticus) were lower than the maximum permitted concentrations recommended by FAO and WHO. The fish of that wetland is good for human consumption.