The Transport of Plutonium, Americium and Curium in the Blood of Rats

Abstract

The rates of disappearance from the blood of plutonium, americium and curium after intravenous injection in various chemical forms has been studied in rats. The rate of removal of plutonium is markedly influenced by the physicochemical form of the injected plutonium and especially by the presence of colloidal material. The plasma clearance rate of plutonium injected as a citrate solution which had been freed from polymeric species, by filtration through a 10 mμ pore diameter filter, is considered to afford a close approximation to the rate of disappearance of plutonium which enters the blood in soluble form from the lung, gastrointestinal tract, or through a contaminated wound. In contrast to plutonium, the plasma clearance rates of americium and curium are more rapid and much less influenced by chemical form. A study of the distribution of plutonium, americium and curium amongst the serum proteins at various times after injection, showed that plutonium was always found mainly in the β₁ globulins but that americium and curium were more generally distributed between the various serum proteins. All the results provide further evidence of the differences between tetravalent plutonium and the trivalent actinides in their reactions with biological systems.