Measured 234,238U and fallout 239,240Pu in human bone ash from Nepal and Australia: skeletal alpha dose.

Human bone samples from Nepal and Australia were analyzed for isotopic uranium and fallout plutonium. The Nepalese samples were obtained for a 3-yr period (1976-78) while the Australian samples are representative of a single year (1977). The surface air plutonium concentrations for the latitude bands of these countries were either measured and/or estimated from 1954 through 1978. With the plutonium air concentrations and age-dependent breathing rates as input data, the measured human bone results were compared with skeletal estimates derived from the ICRP Task Group Inhalation Model, and the agreement was found to be reasonably good. The measured isotopic uranium concentrations in these samples provide a benchmark against which to assess fallout plutonium based upon a comparison of the skeletal alpha radiation dose from a natural actinide to these populations.