Assessment of Outdoor Gamma Radiation Levels and Radiological Health Risks in Selected Oil-Producing Communities of Eastern Obolo, Akwa Ibom State, Nigeria

Abstract

This study evaluated outdoor gamma radiation levels and the associated radiological health risks in selected oil-producing communities within Eastern Obolo Local Government Area, Akwa Ibom State, Nigeria. A cross-sectional field approach was adopted, with in situ measurements carried out across five communities: Okoroete, Iko, Obianga, Okorombokho, and Elepon, using a portable radiation survey meter. The geographical coordinates of all sampling locations were recorded using a handheld Global Positioning System (GPS) device. The measured absorbed dose rates were used to calculate key radiological risk parameters, including annual effective dose equivalent (AEDE), external and internal hazard indices, representative gamma index, and excess lifetime cancer risk (ELCR), based on standard models. The absorbed dose rates ranged from 55.6 to 91.5 nGy/h, with a mean value of 72.2 nGy/h, exceeding the global average of 59 nGy/h reported by UNSCEAR. The AEDE values varied between 0.082 and 0.094 mSv/y, with an average of 0.089 mSv/y, remaining below the recommended public exposure limit of 1.0 mSv/y. The external hazard index (0.38–0.46), internal hazard index (0.45–0.54), and representative gamma index (0.58–0.69) were all below the permissible limit of unity, indicating no immediate radiological risk, the ELCR values ranged from 2.87 × 10⁻⁴ to 3.29 × 10⁻⁴, with most values slightly higher than the global average of 2.9 × 10⁻⁴, suggesting a marginal increase in long-term cancer risk. The findings indicate moderately elevated background radiation levels compared to global averages, although still within internationally accepted safety limits. Continuous environmental monitoring is therefore recommended to ensure long-term radiological safety in oil-producing communities of the Niger Delta