Assessment of Excess Life Time Cancer Risk from Gamma Radiation Exposure Rate in Two Tertiary Institutions in Bayelsa State, Nigeria (Published)
The present study assessed the excess lifetime cancer risk associated with gamma radiation exposure rate in two tertiary institutions in Bayelsa State, Nigeria using Radalert 100xTM, nuclear radiation monitor which uses a Geiger Mueller tube to detect radiation emissions. The studied campuses of Niger Delta University (NDU) and Federal University of Otuoke (FUO) were delineated into eleven (11) and Ten (10) sections respectively. Results of the measurements showed that the highest exposure rate of 0.05mR/h (2.66msvy-1) was recorded at NDUIP against 0.04mR/h (2.128msvy–1) of FUOHL. Excess lifetime cancer risk analysis showed that at NDUIP, it was 1.866 x 10-3 and 1.500 x 10-3 at FUOHL. In calculated mean values for exposure rate (ER), Absorbed Dose Rate (ADR), Annual Effective Dose Equivalent (AEDE) and excess lifetime cancer rate (ELCR) it was; 0.030mR/h (1.596mSvy-1), 238.06nGy/h, 0.290mSvly and 1.020 x 10-3 respectively for NDU and 0.02mR/h (1.064mSvy-1), 204.45 nGy/h, 0.250mSvy-1 and 0.880 x 10-3 respectively in FUO. Compared with world average value (WAV) of 0.013mRlh (0.6916msvy-1) for ER, 59.00nGy/h for ADR, 0.070mSvy-1 for AEDE and 0.290 x 10-3 for ELCR respectively. The calculated dose to organ showed that the testes have the highest organ dose of 0.087mSvy-1 in NDU and 0.070mSvy-1 in FUO respectively. The obtained mean values in both campuses exceed the WAV. However, the obtained results do not impose alarming danger, but effort should be made for control measures in compliance with ALARA Principle.
Keywords: Radiation, Risk Assessment, exposure, lifetime