NATURAL RADIOACTIVITY OF U-238, Th-232 AND K-40 IN SURFACE SOIL OF BAGHDAD, NAHRAIN AND AL-MUSTANSIRIYAH UNIVERSITY IN IRAQ
The study of natural radioactivity in public universities soil is very important because of containing a large numbers of students and personnel in small areas and for long periodic times, especially the centers and gathering student's areas. So it was chosen the most important universities in Baghdad city according with the student's density, which is Baghdad and Nahrain University in Al-Jadriyah region in addition to Al-Mustansiriyah University in Palestine street region. Thirteen soil samples collected from these regions to estimate the radiological impact to the dweller, the concentrations of 238U, 232Th and 40K present in the soil samples were analyzed using HPGe as Gamma-spectrometry. The results showed that the average radioactivity of 238U is 26.262±4.52 Bq/kg, for 232Th is equal to 24.860 ± 4.03 Bq/kg and for 40K is 293.706 ± 16.62 Bq/kg. Thus, the values of specific activity of 238U, 232Th and 40K for all soil samples are in acceptable values of the worldwide average. The maximum value for Raeq is 119.727 ± 10.94 Bq/kg recorded in sample (Bag2), with an average value of 76.938 ± 8.44 Bq/kg. All soil samples have Raeq value below the 247 Bq/kg (Iraqi permissibility limit). In addition to radium equivalent, the absorbed gamma dose rate (D), outdoor annual effective dose and hazard indices are calculated in this work and show low values compared with permissible limits.