Dietary exposure to natural radionuclides in foodstuffs from Bengaluru, India: a radiological and statistical assessment

Naturally occurring radionuclides in foodstuffs constitute an important pathway of internal radiation exposure to the general population. This study evaluated the activity concentrations of 226Ra,232Th, and 40K in commonly consumed food products, including Coorg tea, food supplements, green gram, ragi (finger millet), tapioca, and wheat collected from retail outlets in Bengaluru, India. Gamma-ray spectrometric measurements were performed using a 3″ × 3″ NaI(Tl) detector, and ingestion-related radiological risks were assessed through the estimation of annual committed effective dose (ACED) and excess lifetime cancer risk (ELCR). The measured activity concentrations ranged from 3.32–13.98 Bq kg−1 for 226Ra, 7.10–29.93 Bq kg−1 for 232Th, and 30.39–142.36 Bq kg−1 for 40K. Among the investigated food categories, green gram exhibited the highest mean activity concentration of 40K, whereas Coorg tea showed the lowest radionuclide levels. The estimated ACED values ranged from 0.021 to 0.083 mSv y−1, while the corresponding ELCR values varied from 0.074 × 10−3 to 0.291 × 10−3. All calculated doses were well below the public dose limit of 1 mSv y−1 recommended by the International Commission on Radiological Protection (ICRP), and the associated cancer risks remained within internationally accepted safety levels. Pearson correlation analysis revealed a strong positive relationship between 226Ra and 232Th, suggesting a common natural origin. The results indicate that the analyzed foodstuffs do not pose significant radiological health risks under normal consumption patterns. This study provides updated baseline data on dietary exposure to natural radionuclides in urban food products and food supplements marketed in Bengaluru, India.