Radioactivity Levels and Radiation Hazard Assessment in Soil Samples of Peshawar University

Presence of natural radionuclides (Ra-226, Th-232 and K-40) and man-made radionuclide Cs-137 has been investigated in soil samples collected from Peshawar University campus, Khyber Pakhtunkhwa, Pakistan, using gamma-ray spectrometry. A High Purity Germanium (HPGe) detector was used for gamma spectrometry. The detector was connected with a computer based high resolution multi channel analyzer. The specific activities in soil ranged from 30.2 to 49.1 Bq/kg for Ra-226, 54.8 to 77.3 Bq/kg for Th-232, 9.8 to 46.6 Bq/kg for Cs-137 and 373.6 to 1071 Bq/kg for K-40 with the average values of 40.9, 63.8, 22.5 and 858.3 Bq/kg, respectively. Cs-137, an artificial radionuclide, was also found in measurable concentration in all soil samples of University campus. The detection of Cs-137 showed that the soil of University campus also gained some fallout from Chernobyl power plant nuclear accident in 1986. The radium equivalent activity was found lower than 370 Bq/kg (OECD safe limit) in all the soil samples. The radium equivalent activity, external and internal hazard indices have average values of 198.01 Bq/kg, 0.54 and 0.64, respectively. The mean values of indoor and outdoor absorbed dose rate in air were found 109.36 nGy.h(-1) and 91.13 nGy.h(-1), respectively. In the present analysis, K-40 was the significant radionuclide detected in the University campus soil. The concentration of radionuclides found in the soil samples of University of Peshawar during the present investigations were nominal and do not produce any harmful health effects to the local residents.