Assessment of Radiological Health Risks from Gamma Radiation Levels in Selected Oil Spill Communities of Bayelsa State, Nigeria

Abstract

Measurement of terrestrial background ionizing radiation of oil spilled communities of Bayelsa State, Nigeria was carried out using well-calibrated radalert-100 and 200 meters and a Global Positioning System (Garmin 765). The average exposure rate of the four communities 0.009±0.001, 0.010±0.002, 0.009±0.002 and 0.010±0.002 mRh-1 respectively. The mean of absorbed dose rates estimated in Otuasega, Ibelebiri, Imiringi and Otuegwe are 82.17, 86.13, 73.95 and 83.52 nGy/hr respectively. Estimated values of the annual effective dose equivalent (AEDE) for outdoor exposures 0.13 mSv/yr was obtained in Otuasega, and Ibelebiri while at Imiringi AEDE was 0.15 mSvy-1 and  0.11 mSv/yr was obtained in Otuegwe II respectively. The mean excess lifetime cancer risk calculated for the oil spill values are (0.44, 0.46, 0.40 and 0.45) x10-3 respectively. The obtained values for background ionizing radiation in Ibelebiri and Imiringi oil spill sites was below the recommended standard limits by ICRP  while the absorbed dose (D) and AEDE calculated in the entire oil spill sites are within safe values but the excess lifetime cancer risk (ELCR) estimated were higher than their world permissible values of 0.29x10-3 respectively. The calculated dose to organs showed that the testes have the highest organ dose of 0.085 mSvy-1while the liver has the lowest organ dose of 0.048 mSvy-1. The contour map of Fig. 5 showed low level of BIR sparsely distributed and also the result showed that the oil spilled had little or no impact on the background radiation of the area.