Assessments of Natural Radioactivity and Heavy Metals in Commonly Consumed Milk in Oke-Ogun Area, Nigeria and Estimation of Health Risk Hazard to the Population

摘要

Eight samples of commonly consumed powdered milk by adults were collected from local markets in Oke-Ogun area, Nigeria and analyzed using gamma ray spectrometer with NaI(Tl) detector for radioactive analysis and Atomic Absorption Spectrophotometer for heavy metal analysis (Pb, Fe, Cd and Cu). The main activity concentration detected is that of 40K with average of 39.6 Bq.kg-1 while the activities of 226Ra and 232Th were below detection limit (BDL). The total annual effective dose due to the ingestion of radionuclide in the milk sample was estimated to be 33.7 μSv.y-1 which is lower than the ICRP recommended limit of 1mSv.y-1 for all ages. The geometric means of Pb, Cd, Fe and Cu in the samples were found to be 0.024, 0.328, 2.168 and 0.242 mg.kg-1, respectively and the annual daily dose estimated were 0.1490, 0.010, 0.0002 and 0.0003 mg.day-1, respectively. The results of the hazard index revealed that the intake of heavy metal through ingestion of the milk samples did not exceeds the recommended limit of unity. Therefore, the consumption of these milk samples is safe.