Radiological Assessment of Background Ionizing Radiation Exposure Rates from Solid Mineral Mining Sites in Ikwo Local Government Area of Ebonyi State, Nigeria

Abstract

Human exposure to ionizing radiation from natural and artificial sources is an unending and unpreventable phenomenon on earth. The negative health impact of human activities in the environment has been an issue of discussion in contemporary times. A study to assess the radiological background ionizing radiation exposure dose rates from solid mineral mining sites in Ikwo Local Government Area of Ebonyi State was carried out. An in-situ measurement of BIR exposure rate in mRh-1 for 50 locations was done using a well calibrated   Digilert -200 nuclear radiation meter (S.E international, INC.) at an elevation of 1.0 m above ground level with a geographical positioning system (GPS) for geographical location. The measured BIR exposure rates were utilized to assess the radiological health hazards and radiation effective doses to different body organs using well established radiological relations. To determine the radiological health status of the environment, the collected results were compared to recommended allowed limits.  The mean values of BIR exposure levels (0.02 mRh-1 ), absorbed dose rates (185.39 ηGyh-1 ) and excess lifetime cancer risk (1.00 ×10-3) are higher than their recommended safe limits of 0.013 mRh-1 , 84.0 ηGyh-1 , 0.29×10-3respectively as recommended by ICRP and UNSCEAR. The mean annual effective dose equivalent (0.20 mSvy-1 ) is within recommended permissible limits of 1.00 mSvy-1 for general public exposure. Also, the effective doses to different body organs are all below the recommended limits of 1.0 mSvy-1 . Generally, the study shows that Ikwo solid minerals mining areas are radiologically contaminated due to land excavation and mining activities taking place. However, the contamination has no immediate radiological health effects on the residents of the area, but there is the possibility of long-term health concerns in the future, such as cancer, due to accumulated doses.