THE UNITED-STATES TRANSURANIUM AND URANIUM REGISTRIES - 1968-1993

The historical development and scientific contributions of the United States Transuranium and Uranium Registries are briefly traced. Further to encourage radiobiology studies and to provide unique materials for research in other areas such as biomarkers including oncogenes, the R egistries have established the National Human Radiobiology Tissue Repo sitory, which includes more than 20,000 tissue samples and solutions, histopathology slides, and related materials from persons with interna l depositions, including radium dial painters, available to other inve stigators for collaborative or individual research purposes. Emphasis is given to recent findings of the Registries with respect to biokinet ic models for the actinides and the post-mortem analysis of USTUR Case 0246, an individual who suffered a massive intake of Am-241 eleven ye ars prior to death from heart disease. Registries studies show that, i n addition to skeleton and liver, muscle is an appreciable reservoir f or both plutonium and americium. The systemic biokinetics of plutonium and americium are well represented by a three-compartment model that includes skeleton, liver, and muscle, although the biokinetic paramete rs of these two transuranium elements differ significantly. Initial up take fractions for plutonium are 0.4, 0.4, and 0.2, with residence hal f-times of 50, 20 and 10 years, respectively, for skeleton, liver and muscle. For americium, the comparable uptake fractions are 0.45, 0.25, 0.3 with residence half-times of 50, 2.5 and 10 years for the three c ompartments.