Evaluation of Excess Lifetime Cancer Risk Radiation from Background Ionizing Radiation in Eligbam and Government Residential Area (Gra Phase II)

Abstract

A study of evaluation of excess lifetime cancer risk was carried out in Eligbam and government residential area phase II (GRA PHASE II) in Obio/Akpor local government area, the study was successfully caried out using the GMC-300 Giger Muller counter Radiation Detector to measure background radiation, The geographical coordinates of the various sample points were recorded using the geographical positioning systems (GPS).The measured radiation levels in Eligbam location ranged from 0.007 mR/hr to 0.016 mR/hr with an overall average of 0.012±0.06 mR/hr. The detected radiation levels in GRA phase II varied from 0. 011mR/hr to 0.034mR/hr with an overall mean of 0.0139±0.04mR/hr. Also, the computed absorbed dose from the background radiation levels in Eligbam location varied from 60.9nGy/hr to 139.2nGy/hr with an overall mean of 104.98±20.04nGy/hr. While the calculated absorbed dose from the measured radiation levels in GRA Phase II ranged from 95.7nGy/hr to147.9nGy/hr with an overall average of 120.64±36.96nGy/hr. The annual effective dose equivalent (AEDE) computed for Eligbam varied from 0.09mSv/yr to 0.21mSv/yr with an overall mean of 0.16±0.03mSv/yr. Similarly, the computed annual effective dose rate for GRA Phase II varied from 0.13mSv/yr to 0.45mSv/yr with an overall average of 0.18±0.06mSv/yr. The excess lifetime cancer risk calculated for Eligbam varied from 0.33×10-3 to 0.45×10-3 with an overall mean of 0.56 ×10-3 . The computed excess lifetime cancer risk for GRA Phase II ranged from 0.47×10-3 to 1.57×10-3 with an overall average of 0.66 ×10-3 which is quite higher than the world average. The range of values for the background radiation are all within the acceptable safe limit by the International Commission on radiological Protection (ICRP, 2000). However, the computed values for the absorbed dose, annual effective dose equivalent and the excess lifetime cancer risk are all higher than the ICRP safe limit of 89.0nGy/hr, 1.0mSV/yr and 0.29×10-3 respectively. Although, there is presently no reported health hazard associated to exposure due to ionizing radiation, but adequate caution need to be apply in case of impending danger.