Level of natural radionuclides in foodstuffs and resultant annual ingestion radiation dose

Abstract

The natural radioactivities in three major groups of foodstuff widely consumed in Upper Egypt were determined. The specific activities of ²²⁶Ra, ²³²Th, and ⁴⁰K in cereals, leguminosae, and flour were measured using γ-ray spectroscopy. Another group of hay, water, and soil samples from the same location were also analyzed. Hay samples were found to contain the highest radioactivity concentration among all the samples that were investigated. This increment could be due to the high water content in the shoots which tends to accumulate soluble radionuclides. The average calculated concentrations of soil samples in the present study exhibits the lowest values with respect to those from different countries. In the case of water samples, the average activities of both ²³²Th and ⁴⁰K were similar to those for soil while ²²⁶Ra was twice that of water sample. The annual ingestion dose from each radionuclide was calculated. The computed annual dose owing to daily intake of radium, thorium, and potassium via wheat flour, lentils, and bean in the present study (214.8 μSv) is ten times lower than the global average annual radiation dose (2400 μSv) from the natural radiation sources as proposed by UNSCEAR. The obtained results show that the dose values are quite low and carry insignificant radiation dose to the public.