Abstract
Natural radionuclides in agricultural products may contribute to long-term radiological health
risks through dietary intake. This study assessed the activity concentrations of U-238, Th-232,
and K-40 in vegetables cultivated in irrigation farms within Soba Local Government Area,
Kaduna State, Nigeria, and evaluated the associated radiological health risks. Pepper, onion,
and tomato samples collected from nine locations were analyzed using NaI(Tl) gamma-ray
spectrometry. Radiological parameters, including committed effective dose (CED), lifetime
cancer risk (LCR), and internal hazard index (Hᵢ), were estimated for adults and children using
standard ICRP dose conversion coefficients. The highest radionuclide concentrations were
recorded in Kinkiba, with values of 2.45, 7.93, and 556.84 Bq kg⁻¹ for U-238, Th-232, and K-
40, respectively. Total CED values ranged from 4.86 × 10⁻⁵ to 2.85 × 10⁻⁴ mSv yr-1 for adults
and 1.97 × 10⁻⁵ to 1.37 × 10⁻⁴ mSv yr-1 for children. The maximum LCR obtained was 1.42 ×
10⁻², while all Hᵢ values remained below the recommended safety threshold. Although spatial
variations in radionuclide concentrations were observed, the evaluated radiological indices
indicate low ingestion-related health risk under current exposure conditions. The study provides
baseline radiological data for environmental monitoring and food safety assessment in
agricultural communities