Natural radioactivity for soil samples in primary schools at Najaf city, Iraq

Natural radiation is the most significant contribution to the annual exposure of the world population, making it essential to assess the quantity of natural radiation in soil. This research aims to assess the level of natural radioactivity within the soil samples taken from primary schools in Al-Najaf, Iraq using gamma-ray spectroscopy. Specific activity was determined for the ²³⁸U series (²¹⁴Bi), ²³²Th series (²¹⁸Tl), ⁴⁰K, and ²³⁵U. Twelve radiological hazard indices were computed. SPSS software version 23.0 was employed for data statistical analyzes to include average, standard error, standard deviation, box plot, frequency distribution, and Pearson's correlation coefficient. The results of the concentrations of ²³⁸U, ²³²Th, and ⁴⁰K, were drawn using a geographic information system (GIS) technique. The results showed that the average values and standard error of ²³⁸U, ²³²Th, ⁴⁰K, and ²³⁵U were 20.1 ± 0.65 Bq/kg, 11.5 ± 0.22 Bq/kg, 330.9 ± 7.1 Bq/kg, and 0.926 ± 0.03 Bq/kg, respectively. The results of ²³⁸U, ²³²Th, ⁴⁰K, and ²³⁵U were compared to the average world value. This indicates that some schools' ²³⁸U and ⁴⁰K levels had exceeded the acceptable worldwide levels. At the same time, the results of radiological hazard indices were seen to be within the permissible worldwide levels. As a result, the elementary schools under study can be argued that they are relatively free of natural radiation threats. The resulted data of the current research might be contributed to the database of natural radioactivity levels and radiation doses received by those who come into touch with these schools.