Assessment of Soil Gamma Radiation Riskin Ulaanbaatar City

Abstract

This study assessed the Excess Lifetime Cancer Risk (ELCR) associated with environmental gamma radiation from soil in densely populated areas of Ulaanbaatar, Mongolia. Soil samples collected in 2025 from sampling locations arranged on a 1-km grid were analyzed using an accredited gamma spectrometry laboratory at the National Institute of Nuclear Science and Technology, National University of Mongolia. Based on the measured radionuclide concentrations, the annual effective dose (Eout) and ELCR were calculated. Monte Carlo simulation was applied to evaluate the distribution of the results and measurement uncertainty.The average ELCR estimated using the population risk coefficient was 0.261 × 10⁻³ in 2025, which was lower than the internationally accepted reference level of 0.290 × 10⁻³. However, age-and gender-specific risk assessment showed that ELCR was highest for children, followed by females. The estimated ELCR for children exceeded the reference level at all sampling locations, while that for females exceeded the reference level atmost locations. These findings indicate the need for continued monitoring and more detailed risk assessment for vulnerable population groups and locations with elevated ELCR values.This study provides important baseline information on soil gamma-radiation risk in Ulaanbaatar and contributes to long-term environmental radiation monitoring and radiological risk assessment