Radiological safety assessment of sugar consumption in South Africa-a study of 226Ra, 228Ra, and 40K levels.

Abstract

Human exposure to natural radionuclides in the environment primarily occurs through ingestion of foodstuffs, highlighting the importance of continuous monitoring of radionuclide levels in foodstuffs by ensuring consumer safety and compliance with regulatory standards. Using gamma spectrometry, this study investigates activity concentration levels of 226Ra, 228Ra, and 40K, and associated radiological health risks, in 14 commonly available sugar brands in South Africa. The activity concentration levels of these natural radionuclides 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, with brown sugar having lower values than with 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/year, respectively, and the respective mean values are 0.40 ± 0.11, 0.45 ± 0.14, and 0.17 ± 0.05 mSv/year. 228Ra contributed the 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 wi