Actinides and Long-Lived Radionuclides in Tissues of the Japanese Population: Summary of the Past 20-Year Studies

Radioactive fallout constitutes the major source of contamination of the environment with fission products. Our primary interest was in selected fission products, such as ¹³¹I, ⁸⁹Sr, ⁹⁰Sr, and ¹³⁷Cs, and neutron activation products, such as ³H and ¹⁴C. Plutonium-239,240, ²⁴¹Am and ⁹⁰Tc are generated from nuclear tests, and they are important by-products of nuclear industries. Polonium-210, ²¹⁰Pb and ²³²Th, ²³⁰Th and ²²⁸Th occur widely in nature. These radionuclides enter the human body through inhalation and the ingestion through food and water. These nuclides may cause radiation doses to certain organs of the body. Assessment of the resulting health hazards is an essential public health activity, which demands reliable techniques for the assay of the various radionuclides in man and his environment. In this paper, we present the accumulation of radionuclides from man-made sources and primordial radionuclides in various tissues of the Japanese population. The studies were performed at the Department of Public Health, Akita University School of Medicine, during the periods from 1973 to 1995.