Radiological Dose and Health Risk Assessment of Naturally Occurring Radioactive Materials at Kataeregi Artisanal Mining Site, Niger State Using RESRAD Code

Abstract

This study examined the distribution of naturally occurring radioactive materials (NORMs) and the corresponding gamma radiation exposure in Kataeregi artisanal mining area of Minna, Niger State, Nigeria. To assess radioactive exposure and possible health hazards, a combination of experimental measurements and RESRAD modeling was used. Activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 18.74 0.8, 9.12 1.23 and 360.13 11.96, respectively. Excess lifetime cancer risk (ELCR), annual effective dose (AED), and external gamma dose rates were calculated using the average concentrations. According to the results, the overall dose gradually drops from roughly 4.0 × 10⁻² to 2.2–2.6 × 10⁻¹ mSv/yr, mostly as a result of the decrease in the ⁴⁰K contribution. However, long-term exposure is dominated by ²²⁶Ra, which stays relatively steady, whereas ²³²Th gradually increases until stabilizing. According to the pathway analysis, ingestion pathways, especially fish intake, contribute very little but gradually grow over time, whereas external exposure from contaminated soil accounts for over 85–90% of the overall dose. Low radiological danger is shown by the calculated dose values, which are far lower than the recommended public exposure limit of 1 mSv/yr and the global average of 0.07 mSv/yr. However, the persistence of long-lived radionuclides indicates continual low-level exposure, emphasizing the need for constant monitoring and efficient radiation protective measures.