Assessment of radiological hazards in edible plants from a gold mine in Gauteng Province, South Africa

Background This study assessed the potential health risks from Naturally Occurring Radionuclide Materials (NORMs) in plants collected near a gold mining site in Gauteng Province, South Africa. Methods Eleven plant samples from the mining area and a control site were analyzed using a high-resolution BEGe gamma detector to measure activity concentrations of uranium-238 (²³⁸U), thorium-232 (²³²Th), and potassium-40 (⁴⁰K). Results Plants from the mining area showed slightly higher radionuclide levels (17.4 ± 3.1 Bq/kg for ²³⁸U, 19.7 ± 1.6 Bq/kg for ²³²Th, and 146.7 ± 9.2 Bq/kg for ⁴⁰K) compared with control samples (12.1 ± 1.5, 15.6 ± 1.0, and 125.7 ± 4.8 Bq/kg, respectively). However, all values remained below global averages. The calculated radium equivalent activity (Raeq) was also modest (56.8 ± 4.0 Bq/kg in the mining area vs. 44.1 ± 2.1 Bq/kg in the control area). Estimated radiation exposure indicators—including Annual Effective Dose Equivalent for terrestrial gamma radiation (0.03 mSv/year), ingestion dose (1.24×10⁻³ mSv/year), and external and internal hazard indices (both 0.2)—were all well within internationally accepted safety limits. Conclusion Overall, the radionuclide levels in plants surrounding the mining site pose no significant radiological risk to the public.