Occupational and environmental radiation exposures from small-scale tin ore processing: A case study from Bangka Island

This study assessed the radiation exposure risks from Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) generated during small-scale tin ore processing on Bangka Island, Indonesia. Twenty individuals, including workers and nearby residents, were evaluated. Workers experienced significant occupational exposure, with mean annual doses of 6.87 mGy/y and some exceeding 26.49 mGy/y. Notably, 71% of residents exceeded the International Commission on Radiological Protection (ICRP) public dose limit of 1 mSv/y at their desk locations, indicating elevated environmental contamination risks. For comparison with the mSv-based dose limits, effective dose was approximated from the measured air kerma using ICRP 116 conversion coefficients (1 mGy ≈ 1 mSv for the relevant gamma energies). A significant correlation (R² = 0.6612) was observed between the distance from the workshops and resident exposure, indicating elevated external doses for workers and nearby residents around small-scale tin workshops. Significant differences in exposure were observed between ore workers and non-ore workers, highlighting both direct occupational exposure and indirect residential exposure (body: p = 0.021, r = 0.52; desk: p = 0.010, r = 0.57). Urinary uranium in the ore worker was 14.3 ng/L, while the two controls showed 7.5-8.8 ng/L. These values are reported descriptively because the sample size was too small for statistical comparison. This study demonstrates significant occupational and environmental radiation exposure risks associated with small-scale tin ore processing. These findings point to the need for strengthened radiation protection measures and improved contamination control around small-scale tin workshops.