Soil radioactivity levels, radiation hazard assessment and cancer risk in Al-Sadr City, Baghdad Governorate, Iraq

Natural radioactivity concentrations of 238U, 232Th, and 40K in surface soil specimens from various sectors in Sadr City were collected and measured by HPGe detector.

Twenty specimens were collected from selected sites in the study district. The total average activity concentrations of radionuclides 238U, 232Th and 40K were 15.35±0.82 Bq/kg, 13.31±0.79 Bq/Kg, and 315.39±18.05 Bq/kg, respectively. Correlations between these radionuclides demonstrate a secular equilibrium in the examined soil.

It was found that the average rate of absorbed dose is 87.510±21.555 nGy/h which is below the maximum limit except for specimens S13 and S14, where their values are close to the permissible limit. The indoor gamma-ray absorbed dose rate exceeds the permissible limit in the soil specimens S13 and S14. Radium equivalent activities, external and internal hazard indices, representative, with respect to the examined soil, do not override the global limits. 

Average concentrations of the radioactive elements were lower than the worldwide mean values. 40K concentration and lifetime cancer risk ELCRin  and ELCRtatal in soil specimens S13, S14, and S20 were above the recommended limit, while total annual effective dose equivalent AEDEtatal is very close to the permissible limits provided by UNSCEAR and ICRP.