Excess lifetime cancer risk and committed effective dose associated with dietary exposure to radioactivity of natural origin from mining areas

Abstract

Food safety concerns associated with radiotoxicity risks among consumers are widespread in areas with human activities such as mining. Therefore, the study was carried out to determine natural radioactivity levels in total diets in an area with excessive mining activities. Using validated models, the committed effective dose and excess cancer risk were calculated for consumers based on the activity concentration, food intake, exposure frequency, exposure duration, dose, and risk conversion factors. In addition, the percentage contribution of each radionuclide to the committed effective dose was determined. The results showed that the levels of activity concentration of 226Ra (0.17Bq/kg), 228Ra (0.10Bq/kg), 228Th (0.08Bq/kg) and 40K (33.2Bq/kg) were below global reference values (0.580Bq/kg). The corresponding order of the total committed effective dose for age groups was: 0.179mSv/year (adults) < 0.485mSv/year (children) < 0.571mSv/y (adolescents) < 0.634mSv/year (toddlers) and exceeded the typical level (0.3mSv/year) with the exception of adults. 40K in diets from this study was the highest contributor (48%) to committed effective dose, followed by 228Ra (35%), 226Ra (16%) and 228Th (1%) respectively. Radionuclide-specific excess cancer risk was found to increase in this order: 228Th (7 108) < 40K (3 107) < 226Ra (2106) < 228Ra (3 106). This study showed that both radionuclide-specific and cumulative excess cancer risks (5.5 � 10�6) were all within the protective range (1 104�1 � 10�6). 2021,