Samuel Odumu Ogana JOHN ^1* Stephen Friday Olukotun ^1,2 Moses Mpofana Radebe ¹ Manny Mathuthu ¹

• ¹ Center for Applied Radiation Science and Technology (CARST), North-West University, Mahikeng, South Africa
• ² Department of Physics and Engineering Physics, Obafemi Awolowo University, Ile-Ife 220282, Nigeria

Human exposure to natural radionuclides in the environment primarily occurs through ingestion of foodstuffs, making monitoring essential. The study investigates activity concentration levels of 226Ra, 228Ra, and 40K, and associated radiological health risks, in fourteen commonly available sugar brands in South Africa, using gamma spectrometry. The activity concentrations ranged from 2.01 ± 0.13 to 7.93 ± 0.34 Bq/kg for 226Ra, 2.90 ± 0.10 to 7.09 ± 0.32 Bq/kg for 228Ra, and 209.40 ± 4.79 to 453.20 ± 10.49 Bq/kg for 40K. The respective mean values were 3.83±0.21, 2.90±0.21, and 320.26±7.41 Bq/kg, brown sugar having lower values than white sugar. Annual effective ingestion dose from intake of 226Ra, 228Ra, and 40K, for infants (1-2 years), children (7-12 years) and adults (> 17 years) ranged from 0.28 to 0.69, 0.32 to 0.82 and 0.12 to 0.30 mSv/y, respectively. The respective mean values are 0.40±0.11, 0.45±0.14 and 0.17±0.05 mSv/y. 228 Ra contributed largest proportion to ingestion dose (46 -67 %), indicating potential radiation risk to bones. Lifetime cancer risk ranged from 1.25 × 10-8 to 4.95 × 10-8 for 226Ra, 1.95 × 10-8 to 4.77 × 10-8 for 228Ra and 5.53 × 10-7 to 1.19 × 10-6 for 40K, with a total mean of 8.96 × 10-7±2.31 × 10-7. Total chronic daily intake due to 226Ra, 228Ra, and 40K ranged from 0.26 to 0.56 with mean of 0.39±0.10 (mg/kg-day). The activity concentration levels are within the reference value while annual effective ingestion dose and lifetime cancer risks were found to be below international permissible limits. This indicates that sugar in South Africa is radiologically safe and does not pose significant radiological health risks. The measured activity levels in this study are comparable to those reported in similar studies. This baseline study highlights importance of continuous monitoring of radionuclide levels in foodstuffs ensuring consumer safety, compliance with regulatory standards, and contribute to ongoing discussions on radiological health risks associated with dietary habits. Public health initiatives could consider offering guidelines for safe levels in consumables like sugar, especially for vulnerable populations like children.