Characterization of Radiation Exposure Dose Rate from Waste Dumpsites within Owerri, Nigeria: An Atmospheric Concern

Abstract

This work evaluated the exposure dose rates emanating from five (5) selected waste dumpsites within the Owerri metropolis, Nigeria. The objectives are to measure the dose rates emanating from the selected dumpsites, evaluate the rates at which the radiation exposures diminished with distance at each dumpsite, show the relationship between the emissions emanating from each dumpsite within the metropolis and identify “Safety Zone”, which defined safe regions that can mitigate increased exposure dose rates. The data were acquired by a portable radiation survey meter (Radalert-100) and analyzed using descriptive statistics. The results show that all the waste dumpsites emit radiation that exceeds the ICRP recommended maximum permissible limit of 11.4 μR hr-1 for members of the public. However the radiation exposure dose rate obeying the inverse square law were observed to diminish with varying distance from the linear regression equation of the trends having rate values of -0.398 µR hr-1 m-1, -0.266 µ R hr-1 m-1, -0.348 µR hr-1m-1, -0.369 µR hr-1 m-1, -0.237 µR hr-1 m-1 and -0.323 µR hr-1 m-1 for dumpsites 1 to 5 and the areal average respectively. The exposure dose rate at each of the dumpsites significantly correlated to one another and to the areal average at 95% confidence level, then the attributes of one waste dumpsite stands for the other. The “Safety Zone” from all waste dumpsites was computed from the linear regression equation of the trends. This study is imperative as it point at a way in mitigating radiation exposure dose rates from waste dumpsites in developing cities around the world with similar attributes to Owerri metropolis, Nigeria.