Risk Assessment of Outdoor Gamma Radiation in Some Coastal Communities of Delta State, Nigeria

An assessment of background ionization radiation and associated health risk in some coastal communities of Delta State, Nigeria was carried out using a well calibrated portable radiation detector (Radalert-200) and GPS (Garmin GPS 72H) for the measurement of the geographical locations. The study covered Abiteye and Anotech Jetty water ways with nine notable communities assessed, where marine transportation and equipment haulage are predominant. The exposure rates ranged from 0.011 to 0.019 mRh−1 with overall mean value of 0.015 ± 0.002 mRh−1. The computed absorbed dose rates ranged from 95.70 to 165.30 nGyh-1 with overall mean value of 132.46 ± 19.05 nGyh-1. The estimated overall mean annual effective dose equivalent (AEDE) for the studied communities was 0.203±0.03 mSvy-1, while the overall mean excess lifetime cancer risk (ELCR) was (0.710±0.10) x10-3. The dose received by organs was highest in the testes (18%), the ovaries received 13%, while the liver had the lowest dose values (10%). Among all the estimated risk parameters, only the overall mean AEDE was found to be below the safe world recommended standard value while others were higher than their respective safe world average values. Hence the exposure may not constitute any immediate health risk to the resident of the study area.