Natural radioactivity and radiation risks of soils in Ali Al-Sharqi and Kumait, Iraq

Humans are subjected to natural radiation from external sources, such as radionuclides on Earth and cosmic radiation, as well as internal radiation from radionuclides integrated into the body. Radionuclide intake occurs mostly through the ingestion of food and water, as well as inhalation. The natural radioactivity in the soils of Ali Al-Sharqi and Kumait, two cities in Misan province, Iraq, were measured. The soil samples were collected from 47 Ali Al-Sharqi and Kumait areas, and levels of natural radionuclide were analyzed using a high-purity germanium detector. The average activity concentrations of radionuclides, radium-226, thorium-232, and potassium-40, were found to be 15.1 ± 2.5, 14.7 ± 2.4, and 180.8 ± 7.9 Bq/kg, respectively, for Ali Al-Sharqi. In Kumait, the corresponding values were 13.6 ± 2.1, 17.2 ± 2.4, and 193.6 ± 8.6 Bq/kg, respectively. Radiation risk parameters were also evaluated for both cities. The average radium equivalent activities for Ali Al-Sharqi and Kumait were 50.2 Bq/kg and 53.2 Bq/kg, respectively. Internal and external hazard indices were 0.2 and 0.1, while the gamma level index was 0.2 in both cities. In Ali Al-Sharqi, the absorbed gamma dose rates in the air (Din, Dout, and Dtot) were 44.8, 23.5, and 68.3 nGy/h, the annual effective dose equivalents (AEDEin, AEDEout, and AEDEtot) were 0.2, 0.02, and 0.2 mSv/y, the excess lifetime cancer risks (ELCRin, ELCRout, and ELCRtot) were 0.8 × 10−3, 0.1 × 10−3, and 0.9 × 10−3, and the annual gonadal dose equivalent was 165.3 μSv/y. In Kumait, the corresponding values were 47.2, 24.8, and 72 nGy/h, 0.2, 0.03, and 0.3 mSv/y, 0.8 × 10−3, 0.1 × 10−3, and 0.9 × 10−3, and 175 μSv/y, respectively. These findings indicate that the measured levels of radioactivity and health hazard parameters in both cities were below the global average values reported by the United Nations Scientific Committee on the Effects of Atomic Radiation. Therefore, the natural radioactivity in the soils of the investigated areas does not pose a health risk to the public.