Study of natural radioactivity (226Ra, 232Th, and 40K) in soil samples for the assessment of average effective dose and radiation hazard parameters

Abstract

The radioactivity concentration and the natural gamma absorbed dose rates of the terrestrial radionuclides (226Ra, 232Th, and 40K) have been measured in soil samples collected from Thoubal and Bishnupur districts, Manipur, India, using high purity germanium detector. The range of activity concentration of 226Ra, 232Th, and 40K in the soil from the studied areas varies from 28.7 Bq/kg (Thoubal College) to 126.0 Bq/kg (Kakching Khunou College), 27.2 Bq/kg (Ikop Pat) to 203.5 Bq/Kg (Kakching Khunou College), and 335.6 Bq/kg (Nongpok Sekmai) to 1953.9 Bq/kg (Mantak) with overall mean values of 69.8, 76.6, and 1028.0 Bq/kg, respectively. The radium equivalent activities (Raeq) have been evaluated in soil samples for the assessment of the radiation hazard. The corresponding absorbed dose rate, annual effective dose, and external radiation hazard index in the study area range from 54.5 to 239.3 nGyh−1, 0.3 to 1.5 mSv, and 0.3 to 1.4 with an average value of 121.4 nGyh−1, 0.7 mSv, and 0.7, respectively.

Keywords

• High purity germanium gamma spectrometry
• natural radioactivity (226Ra
• 232Th
• and 40K)
• radiation hazard index
• radiation hazards