A radiological study of radon concentration in commonly used herbal medical plants and its probable environmental and public health impacts

Natural radon in medicinal plants represents a potential source of internal radiation exposure. This study aims to assess radon activity concentration and the related radiation hazard indices in 65 commonly consumed medicinal plants. The solid-state detector (CR-39) measured radon levels using the sealed-can technique. The average radon concentration in the confined air above the samples was 25.07 ± 0.45 Bq m⁻ ³, whereas the average radon level within the plant matrices was 1073.68 ± 21.34 Bq m⁻ ³, indicating higher levels and intrinsic radionuclide content. The average radium activity was 0.201 ± 0.003 Bq kg⁻ ¹, remaining below global limits of 35 Bq kg⁻ ¹, and showed a strong positive correlation with radon accumulation (R² = 0.76). The average annual effective dose from radon ingestion was 0.021 ± 0.000 µSv y⁻ ¹ for low consumption, increasing proportionally to 0.205 ± 0.003 µSv y⁻ ¹ under high-consumption scenarios. These values are below the recommended dose limit of 1 mSv y⁻ ¹. The average excess lifetime cancer risk values (0.079 ± 0.001 × 10⁻ ⁶ - 0.790 ± 0.013 × 10⁻ ⁶) were lower than safety limits of 2.9 × 10⁻⁴. The findings indicate that regular consumption of the investigated medical plants is unlikely to present a significant environmental health risk.