Investigation of radiological health indices from background ionizing radiation levels in Swali Market, Yenagoa, Nigeria

Abstract

Investigation of Radiological Health Indices from Background Ionizing Radiation levels in Swali Market was carried out using well-calibrated radalert-100 and 200 meters and a Global Positioning System (Garmin 765). The measured average exposure rates at seven different sections of the market were 0.017±0.005 mRh^-1(Entry point/market junction), 0.016±0.005 mRh^-1(Centre), 0.017±0.005 mRh^-1(Exit area), 0.018±0.003 mRh^-1(River bank), 0.016±0.004 mRh^-1(Dump area), 0.015±0.007 mRh^-1(Park zone) and 0.014±0.005 mRh^-1(Road side). The mean absorbed dose rates estimated in these sections of the market were 147.90, 142.68, 143.55, 158.78, 139.20, 132.68, and 118.90 nGy/hr respectively. Minimum annual effective dose equivalent (AEDE) for outdoor exposure of 0.18 mSv/yr was obtained at the road side of the market while the maximum value of 0.24 mSv/yr was obtained along the river bank. The calculated mean excess lifetime cancer risk (ELCR) was (0.74 x10^-3) as against the permissible limit of 0.29x10^-3. The results of exposure to background ionizing radiation in Trailer park zone and Road side were in agreement with the standard limit of 0.013mRh^-1as recommended by the International Committee on Radiation Protection (ICRP) while in other areas the results were slightly above the ICRP recommended value. The computed absorbed doses (D) estimated were marginally higher than the safe value, however the average AEDE of the entire market was within safe value of 1.0mSvy^-1. The analysed dose to organs showed that the testes has the highest organ dose of 0.492 mSvy^-1 while the liver has the lowest organ dose of 0.276 mSvy^-1. In general, the results showed that the Swali market pose no serious radiological burden on the traders.

Keywords: Health indices; Investigation; Radiological risk; Swali market