Radiation Mapping of Osun State, Southwestern Nigeria, Measuring The Status of Radioactivity

Abstract

The Fukushima Daiichi nuclear disaster happened in Japan long ago in 2011, and it resulted in the emission of radioactive substances into the atmosphere. These substances were transported by air currents and were detected in several parts of the world, including Nigeria. In the aftermath of the event, it has become necessary to determine the spatial distribution of radioactivity within Osun state. This present study aims to investigate and identify areas of high gamma radiation in Osun State. This study utilised a Garmin GPS and a Geiger Muller counter radiation detector over the entire state. This study presents a radiation map of Osun state. It shows that the region has an elevation range of 190 m to 600 m, and the elevation chart shows that in comparison to the extreme south of the research region, the extreme north is distinguished by high heights. The average ionising radiation within the state ranges from 0.08 to 0.3l µSv/hr. Places including Ila, Boluwaduro and Obokun recorded the highest elevation, which in turn also had the highest dose of gamma radiation, while Ife North, Ife South, Isokan, and Irewole axis recorded their lowest figures of elevation and also had low doses of gamma radiation. The average annual effective dose rate was 0.33 mSvy-1 which is greater than 0.07 mSvy-1 for outdoor exposure. Therefore, it is important to take appropriate safety measures by wearing protection shields to avoid or minimise exposure to high levels of gamma radiation. Keywords: Fukushima Daiichi, Gamma Radiation, Geiger Muller Counter, Radiation Map, Annual Effective Dose

Keywords

• Fukushima Daiichi, Gamma Radiation, Geiger Muller Counter, Radiation Map, Annual Effective Dose