Natural radioactivity and heavy metals measurement in rice and flour consumed by the inhabitants in K.S.A

The natural radionuclide’s 226Ra, 232Th and 40K and some heavy metals (Fe, Cd, Zn, Cu, Mn, Ni, and Pb) were measured in the rice and the flour samples consumed in Saudi Arabia. Gamma ray spectrometry was used to determine the activity concentration of the three nuclides. Heavy metals were analyzed by an inductively coupled plasma optical emission spectrophotometer (ICP-OES). The results indicate that the average concentration of 226Ra, 228Th, and 40K in the rice samples were 1.08, 1.19 and 83.08 Bq kg-1, respectively. While, in the flour samples, the average concentrations were 1.65, 1.61 and 171..31 Bqkg-1, respectively. The ingestion doses were calculated to be 0.224μSvY-1for the rice and 0.471 μSvY-1 for the flour samples which are below the recommended 1 mSv limit. The concentration of heavy elements (Fe. Cd, Mn, Ni, and Pb) in the rice and the flour samples were below the detection limits. Whereas, the mean contents of Cu were 3.75 mg/kg and 3.6 mg/kg of the rice and the flour samples, respectively. The mean values of Zn in the rice and the flour samples were 19.42 mg/kg and 17.3 mg/kg, respectively. The daily intake of Cu and Zn through the rice and the flour samples were lower than the tolerable daily intakes by FAO/WHO; this indicates there is no risk due to the intake of these foods to the people.