Health risk assessment of heavy metals and radionuclides in waste and soil near scrap smelting industries in Ile-Ife and Ikirun, Nigeria

The smelting plants facilitate the recycling of metal wastes as well as a secondary source for metal production. Nevertheless, the wastes from such plants may present routes of heavy metal and radionuclide contamination in the environment. Soil and waste samples from iron smelting industries in Ikirun and Ile-Ife, Osun State were analysed for heavy metal and radionuclide concentrations using Atomic Absorption Spectrophotometer and Gamma Spectrometer, respectively. The concentration of the heavy metals in the soil samples ranged from Not Detectable (ND) for Cd and Pb to 110 mg/kg in Cu and ND for Cd to 812 mg/kg for Cu in the waste samples. The activity concentrations of the radionuclides ranged from 3 Bqkg-1 for U-238 in the waste to 1056 Bqkg-1 for K-40 in the soil samples. The contamination load, degree of contamination, pollution load index and environmental risk factor ranged from 0 to 45, 2 to 105, 0.3 to 12 and 3 to 1640, respectively in the soil and waste samples. The results for the pollution indices showed that the waste samples were more contaminated than the soil samples. Thus, there might be future contamination of the environment with heavy metals as a result of the leaching of accumulated heavy metals from the waste. Though the concentrations of all the heavy metals, except Cu, were below the highest set by the Finnish Legislation for contaminated soil. The radium equivalent showed that the smelting activities poses no radiological risk to the workers and the environment since the results of the radium equivalent were less than 370 Bqkg-1 .