Evaluation of Excessive Lifetime Cancer Risk Due to Gamma Radiation on Rocks in Shira Village, Bauchi State Nigeria

Abstract

This study evaluates the natural radioactivity levels and the associated excess lifetime cancer risk (ELCR) due to gamma radiation from rock samples in Shira Village, Bauchi State, Nigeria. Terrestrial radiation arises primarily from radionuclides such as ²³⁸U, ²³²Th, and ⁴⁰K present in geological formations. Understanding these radiation levels is essential for monitoring environmental safety and assessing public health risks. A total of 100 rock points were randomly sampled, and radiation readings were measured using a radiation survey meter. The absorbed dose rate in air was found to range from 70.0056 to 590.0472 nGy/h, with an average value of 228.9183 nGy/h, significantly exceeding the world average of 59.00 nGy/h. The excess lifetime cancer risk (ELCR) for indoor and outdoor exposure ranged from 1.201966 × 10^-3 to 10.13087 × 10^-3 and 0.300492 × 10-3 to 2.532719 × 10^-3, respectively, with a total average of 4.913045 × 10^-3. These values are considerably higher than the global average of 0.29 × 10-3, indicating a potentially elevated health risk for residents in the study area. The results underscore the need for regular monitoring and the implementation of appropriate mitigation strategies to safeguard public health in Shira Village.