Evaluation of the background ionizing radiation and health status of personnel in laboratories at some Tertiary Institutions in Delta State
Exposure to ionizing radiation even at low doses may be harmful to cells. In this study, an in-situ measurement of Background Ionization Radiation (BIR) exposure rate in laboratories Tertiary Institutions in Delta State, Nigeria was carried outusing a Geiger Muller counter (GMC 320+). The purpose is to estimate the BIR health parameter and hence predict the radiation health status of personnel in these laboratories. For all the measurements readings were taken three consecutive times at a height of one metre above the ground for each point. A geographical positioning system (GPS) was used to determine the coordinates of the study areas. The results indicate that the mean values of the exposure rates range from 0.05 – 0.17 μSv/hr for indoor and 0.08 – 0.14 μSv/hr for outdoor. The obtained annual effective dose equivalent (AEDE) values for the selected institutions range from 0.63 – 1.02 mSv/yr for the indoor and 0.15 – 0.24 mSv/yr for outdoor. These values are within the recommended safety limit of 1.0 mSv/yr by the International Commission on Radiation Protection. The calculated mean excess lifetime cancer risk (ELCR) for the institutions range from 1.72 x 10-3 – 2.77 x 10-3 for the indoor environment. These values are higher than the 0.29 x 10-3 value recommended by United Nations Scientific Committee on the Effects of Atomic Radiation. This implies the laboratory personnel in these institutions are likely to develop cancer at the age of 55 years and above. There is the need for regular monitoring by the relevant body.
Keywords: Indoor/Outdoor Radiation, Annual Effective Dose Equivalent and Excess Lifetime Cancer Risk.