Quantification of ²²⁶Ra, ²³²Th, and ⁴⁰K in four species of Talinum leaves grown in southwestern Nigeria: A radiological risk evaluation

Naturally occurring radionuclides in edible plants contribute to internal radiation exposure in humans. This study quantified ²²⁶Ra, ²³²Th, and ⁴⁰K in four Talinum species ( T. paniculatum, T. triangulare, T. fruticosum, and T. portulacifolium ) cultivated in southwestern Nigeria to assess potential radiological risks. Fresh leaf samples were collected, washed, oven-dried, homogenized, and analyzed using a NaI(Tl) gamma-ray spectrometer. Radiological risk indices, including radium equivalent activity (Raeq), absorbed dose rate (D), annual effective dose equivalent (AEDE), external hazard index (Hex), internal hazard index (Hin), and ingestion dose (Eing), were computed. Mean activity concentrations ranged from 9.22 ± 0.79 to 10.01 ± 0.51 Bq kg⁻¹ for ²²⁶Ra, 7.36 ± 0.41 to 8.21 ± 0.71 Bq kg⁻¹ for ²³²Th, and 110.72 ± 8.21 to 129.90 ± 4.75 Bq kg⁻¹ for ⁴⁰K. Calculated Raeq (24.3–27.4 Bq kg⁻¹), absorbed dose rates (11.8–13.4 nGy h⁻¹), and AEDE (0.014–0.016 mSv y⁻¹) were below international safety limits, and ingestion doses (8.21–9.15 µSv y⁻¹) were negligible compared with the global average annual background dose (~2.4 mSv y⁻¹). These results indicate that consuming these Talinum species poses no significant radiological health risk. Observed variations among species likely reflect differences in soil composition, pH, and fertilizer application. Findings align with earlier studies reporting low natural radioactivity in edible vegetables and underscore the importance of continued environmental monitoring, especially in agricultural and industrial areas that may influence radionuclide accumulation in crops.