DETERMINATION OF ANNUAL EFFECTIVE DOSE FROM MEASURED SOIL RADIOACTIVITY LEVELS IN AUYO LOCAL GOVERNMENT AREA JIGAWA STATE.

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 Auyo Local Government Jigawa State. In the present study, activities of ²²⁶Ra, ²³²Th and ⁴⁰K are measured in soil samples, the measured mean specific radioactivity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K in the studied samples were 31.25 ± 1.17 Bqkg^-1, 48.97 ± 2.29 Bqkg^-1 and 554.78 ± 18.55 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 (Ra_eq), outdoor radiation hazard index (H_ex), indoor radiation hazard index (H_in) and absorbed dose rate (D) for the area under study were determined as 143.73 Bqkg^-1, 0.39, 0.47 and 66.78 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.