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

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 (Raeq), outdoor radiation hazard index (Hex), indoor radiation hazard index (Hin) 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.

人类持续受到来自陆地、地外及人为放射性核素所产生的电离辐射照射。为评估土壤天然放射性照射相关风险，研究团队在吉加瓦州奥约地方政府辖区开展了放射环境监测调查。本研究对土壤样品中的镭-226（226Ra）、钍-232（232Th）及钾-40（40K）活度进行了测量；受试样品中上述核素的平均比活度浓度分别为31.25±1.17 Bq·kg⁻¹、48.97±2.29 Bq·kg⁻¹及554.78±18.55 Bq·kg⁻¹。基于实测活度浓度，研究人员计算得到镭等效活度、外照射危害指数、内照射危害指数、陆地吸收剂量率及年有效剂量。本研究区域的平均镭等效活度（Raeq）、室外辐射危害指数（Hex）、室内辐射危害指数（Hin）及吸收剂量率（D）分别为143.73 Bq·kg⁻¹、0.39、0.47及66.78 nGy·h⁻¹。年有效剂量当量（AEDE）的取值范围为0.10 mSv·y⁻¹至0.16 mSv·y⁻¹。基于实测活度与危害指数计算结果，本研究得出结论：本次调查区域不会对当地人群及环境构成显著放射学风险。