Measurements of Natural Radiation in soil of the College of Education, University of Kufa, Al-najaf Al-ashraf, Iraq

The natural radiation of soil samples in the education college for girls which is located in Kufa University in Al-Najaf Al-Ashraf govern mate have been studied. A total of 10 Soil samples were collected randomly in October 2010 then kept aside for about 4 week to ensure the equilibrium has been reached between ²²⁶ Ra and its decay products of short half –life and ²²⁸Ra and its decay products before they were taken for gamma spectrometric analysis. The obtained values of the activity concentrations (Bq.kg^-1) were determined for the radionuclides ²³⁸U, ²²⁶Ra, ²³²Th, ²²⁸Ra, and 40K. The presented results of the contents of radionuclides in soil samples showed the minimum activity concentration 4.48±0.8Bq kg-1 of 226Ra was determined in the soil sample No. 9, while the maximum value of 49.89±10.08 Bq kg^-1 was found in the soil from the sample No. 2. The activity concentrations of ²³²Th were in the range 0.87±0.2 Bq kg^-1 to 11.53±2.5 Bq kg^-1 with a minimum value for the sample No. 1 and a maximum for the sample No. 8. The 40K concentrations are disbursed as minimum value 34.54±6.7 Bq kg^-1 in sample No.1 and maximum value 236.78±93.5 Bq kg^-1 in sample No. 6. The highest annual effective dose rate was found to be 139.88 (μSv/y) while the world average annual effective dose equivalent is 460 (μSv/y). The corresponding gamma radiation hazard indices, annual effective dose and gamma activity concentration index (Iγr) were below those of the limit considered acceptable.