Calculate the Rate of Natural Radioactivity in the Soil of Some Schools Using the NaI(Tl) Detector in the City of Hilla-Iraq

Abstract

Activities and risk markers in 15-20 cm soil samples from Hilla City schools were thoroughly examined. This was made possible by the NaI(Tl) detector. The results indicated that the specific activity values for ²³⁸U from 2.244±0.06 Bqkg^-1 to 23.637±0.60 Bqkg^-1, with an average value of 11.70±0.39 Bqkg^-1. Similar to ²³²Th, the average specific activity level was 8.53±0.31 Bqkg^-1, ranging between 1.603±0.09 Bqkg^-1 and 21.503±0.56 Bqkg^-1. For ⁴⁰K, its specific activity range was 222.96±2.72 to 441.824±2.78 Bqkg^-1, with an average of 375.32±2.71 Bqkg^-1. The average radiative forcing of the radium equivalent (Ra_eq) was calculated to be 52.80 Bqkg^-1. The external risk index (H_ex) was 0.14, and the internal risk index (H_in) was 0.17. The gamma risk index (Iγ) was determined to be 0.41. Also, the average outdoor absorbed dose level D_out is 26.35 nGyh^-1, while the average indoor absorbed dose level D_in is 50.54 nGyh^-1. The average annual values of effective dose equivalents (internal and external) are 0.03 and 0.25 nGyh^-1. The additional lifetime cancer risk ELCR_(t) due to natural radioactivity in the models was 0.93x10^-3.  Note that the global average permissible nuclide concentration was 30, 32, and 420, and the danger index values were 1, 1, 6, 59, 84, 0.4, 0.07, and 1.45, respectively, based on the report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). After carefully comparing the study results with permissible global averages, they fit well within the recommended range.