GIS MAPPING OF BIR LEVELS AROUND FOSSIL FUEL AND GAS DISPENSING STATIONS AND ASSESSMENT OF THEIR RADIOLOGICAL RISK IMPLICATIONS
The assessment of terrestrial background ionizing radiation levels within fossil fuel and gas dispensing environments to evaluate the radiological risk around Warri metropolis has been conducted using a digilert 200 Nuclear Radiation monitor meter and a GPS. The GIS monitoring of the BIR levels was carried out between September and December 2018 by delineating the city into eight zones using GIS mapping. The measured average exposure rates ranged from 0.006mRh-1(0.50 𝑚𝑆𝑣𝑦-1) to 0.026mRh-1(2.19𝑚𝑆𝑣𝑦-1) with an overall mean value of 0.015±0.004mRh-1 (1.26±0.32 𝑚𝑆𝑣𝑦-1). The estimated mean outdoor absorbed dose rate for the regions ranged from 116.60±40.38nGyh-1 in Jeddo region to 148.9±49.63nGyh-1 in PTI region and a mean of 129.82±32.98𝜂Gyh-1.The AEDE evaluated is 0.16±0.04 𝑚𝑆𝑣𝑦-1 while the ELCR value is 0.56±0.014µ𝑆𝑣𝑦-1. The estimated dose to organs testes receiving the highest organ dose of 0.10 𝑚𝑆𝑣𝑦-1 while the liver receives the lowest dose to organ of 0.06 𝑚𝑆𝑣𝑦-1. The GIS mapping of the examined facilities revealed that radiation levels in 38 of the 61 sampling locations (62.3%) exceeded the global ambient permissible level of 13.0 𝜇Rh-1 (1.0 𝑚𝑆𝑣𝑦-1) reported by UNSCEAR, therefore the measured values are adjudged high and the environment radiologically impaired. But, these may not cause any short- team health risk to the fuel/gas attendants and attendees in these stations. The obtained estimated excess lifetime cancer risk indicates low chances of contracting cancer and the radiation doses to the adult organs investigated is insignificant.