Assessment of Annual Effective Dose from Measured Soil Radioactivity Levels Using HPGe Detector

Abstract

Human beings are persistently exposed to ionizing radiation caused by terrestrial, extra-terrestrial and anthropogenic radionuclides. In order to assess the risks associated with exposure due to the natural radioactivity in soil, a radiological environmental monitoring survey was carried out in district Chakwal. In the present study, activities of 226Ra, 232Th and 40K are measured in soil samples using an HPGe based gamma spectrometry system. The measured mean specific radioactivity concentration of 226Ra, 232Th and 40K in the studied samples was 31.08 ± 1.2 Bqkg-1, 47.67 ± 2.30 Bqkg-1 and 558.23 ± 17.52 Bqkg-1, respectively. From the measured activity concentration, radium equivalent activity, external and internal hazard indices, terrestrial absorbed dose and annual effective dose were calculated. Mean radium equivalent activity (Raeq), outdoor radiation hazard index (Hex), indoor radiation hazard index (Hin) and absorbed dose rate (D) for the area under study were determined as 142.18 Bqkg-1, 0.38, 0.47 and 66.13 nGyh-1 respectively. The annual effective dose equivalent (AEDE) varied in the range from 0.10 mSv y-1 to 0.16 mSv y-1. On the basis of measured activity and calculated values of hazards indices, it is concluded that the surveyed area does not pose any significant radiological risk to the population and environment.