Recent animal studies on the deposition, retention and translocation of plutonium and other transuranic compounds

In recent years experimental animal studies have been extended to include transuranics other than plutonium. This has allowed their behaviour in the body to be compared with that of plutonium. Americium and curium, regardless of the chemical form in which they are inhaled, are largely translocated to liver and skeleton and do not accumulate in thoracic lymph nodes to the extent that 239PuO2 does. Inhaled 238PuO2 has been found to be translocated from lung to liver and skeleton more than 239PuO2 but not as much as curium and americium oxides. Experimental data are suggestive that particle size characteristics of the inhaled aerosol and the method of preparing the aerosol, as well as the magnitude of the amount initially deposited in the lungs, may alter pulmonary retention and translocation rates. However, these effects have been inadequately studied. Also needing study are mixtures of transuranics which are the forms most likely to be encountered in accidental releases. Knowledge of the behaviour of inhaled transuranics supports the need for continued development of therapeutic measures to remove the transuranics from skeleton, liver and other soft tissues as well as from the lungs. (author)