The Metabolism of Curium in the RAT

The heaviest of the known elements is curium, which was recently discovered by Seaborg and his associates. This new element can be produced by the alpha particle transmutation of plutonium by the following reaction: {sub 94}Pu{sup 239} + {sub 2}He{sup 4} {yields} {sub 96}Cm{sup 242} + {sub 0}N{sup 1} This isotope of curium is radioactive and decays by the emission of an alpha particle to form plutonium 238 which, in turn, is also radioactive. Curium 242 has a half-life of 150 days, and its radioactive daughter, plutonium 238, has a half-life of 50 years. This isotope of plutonium decays by the emission of an alpha particle to form uranium 234 which has a half-life of 233,000 years. Shortly after the organization of the Atomic Energy Project, it became apparent that formidable problems would be presented as the result of the release of nuclear energy. One of the most urgent of these was the hazard presented by the production of large quantities of the radio-elements created by the fission of uranium and the coincidental formation of neptunium and plutonium. In an attempt to evaluate the potential danger presented by these radio-elements from the chain reacting pile, a large series of metabolic studies with experimental animals were undertaken in a number of laboratories working upon the Atomic Energy program. These studies, which have been briefly summarized elsewhere, included a series of investigations on the metabolism in the rat of the more important members of the fission products in the carrier-free state, as well as most of the heaviest elements at the end of the periodic table. These studies made it possible to predict on a semi-quantitative basis the potential hazards that this large number of radioactive elements might present should they gain entry into the body.