This publication is intended to review, update and extend the information on the metabolism of plutonium, neptunium and the trivalent actinides, previously reviewed in ICRP Publication 19, with special reference to the absorption from the gastro-intestinal tract, the retention times in liver and skeleton, the influence of bone remodelling on the microdistribution within the skeleton and the relation of actinide metabolism to that of other radionuclides. This report is intended to complement, rather than replace, the original report and it has not been thought appropriate to reproduce all the extensive data presented in ICRP Publication 19. The new report follows the general patter of the first one, beginning with a short overview of some salient features of the chemistry of the actinides in mammalian systems and then reviewing the behaviour of the elements following entry by inhalation, by ingestion, or through the skin. The penultimate chapter reviews the retention of plutonium and the actinides in liver, bone, gonads and the other organs of the human body.
