CONTENTS OF CESIUM, IODINE, STRONTIUM, THORIUM, AND URANIUM IN SELECTED HUMAN ORGANS OF ADULT ASIAN POPULATION

Abstract

Contents of cesium, iodine, strontium, thorium, and uranium in some selected human organs were estimated for adult Asian population using data obtained in four Asian countries: China, India, Philippines, and Republic of Korea, as part of a Coordinated Research Program of the International Atomic Energy Agency on "Ingestion and Organ contents of elements of importance in radiation protection." These countries together represent more than 40% of the world population. Highly sensitive analytical techniques were employed to measure cesium in skeletal muscle, iodine in thyroid, strontium in skeleton, thorium and uranium in skeleton, liver, kidneys, and lungs where, in comparison to other organs, these elements are present in higher concentrations. The organ contents for adult Asian population, when compared with the corresponding data proposed for Reference Man by International Commission on Radiological Protection (ICRP), showed about 40 times lower kidneys content and about 10 times lower skeleton content of uranium. The content of thorium in skeleton for Asian population was also half of the ICRP Reference Man value. Interestingly, organ contents for the other elements such as iodine in thyroid, cesium in skeletal muscle, and strontium in skeleton were comparable for Asian and the Caucasian population (represented by ICRP Reference Man). Organ contents for these elements were also calculated by applying the new ICRP models of these elements to their daily intakes. The comparison of the calculated and measured organ contents showed that despite uncertainties in the organ content values arising due to the inter-country variations in daily dietary intakes, the contents were within a factor of two to three. This observation is significant since human data both on organ contents and ingestion were obtained at environmental level of intakes. The study suggests that currently available ICRP models for these elements are quite realistic.