A review of annual effective dose from ingesting 226Ra, 232Th, and 40K in rice across different countries.

Abstract

This review synthesises studies from various countries that have assessed the concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in rice. Rice is a primary diet source for over 50 % of the global people, particularly in Asia. Thus, the estimation of the annual effective dose due to the ingestion of ²²⁶Ra, ²³²Th, and ⁴⁰K in rice has become an important area of study in food safety and human health risk assessment. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in rice were found by gamma spectroscopy using sodium iodide scintillation (NaI (Tl)) and high purity germanium (HPGe) detectors. Even if the activity concentration of ⁴⁰K in Thailand rice is higher than 400 Bq kg^-1, the other present rice investigations demonstrate that the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K are smaller than the world limit values of 35, 30, and 400 Bq kg^-1, respectively. Although the people of the Asia continent consume the highest rate of rice, the highest ingestion annual effective dose due to these radionuclides through consuming rice was found in Africa. It was found that the highest ingestion annual effective doses of ²²⁶Ra, ²³²Th, and ⁴⁰K from eating rice were 645.49 μSv y^-1 in Thailand, which is greater than the average value of 290 μSv y^-1 worldwide. For public health officials, researchers, and legislators who are worried about radioactive exposure from food sources, this review is an invaluable resource.