- ll - Page 7. lings 23-27 - "Another explanation for the apparently higher solubility of Pud. than 2385 U0 is the possibility that the intense alpha radiolysis of the lung fluid at the surface of the particles leads to the production of chemically active free radicals which in turn react with Pu0y molecules on the particle surface." Comments: The author is incorrect; presumably a typographical error occurred. We expect that "...higher solubility of 239P Ww, than 238 Pudy is..." should read "...higher solubility of *38puo, than *9%puo, is...". In the experiments referred to (29), "intense alpha radiolysis" seems rather inappropriate to describe the irradiation of a solvent surrounding a submicrometer particle of 239PW05 or 238pu09 which are probably widely separated in the lung. A 0.44 um ?38pw0, particle of the same size emits only 3 alpha particles per hour. In well buffered solvents such as were used in the dissolution experiments, radiolysis products are probably quickly inactivated at the slow rate and in the small quantities that they are formed. Page 8, lines 2-6 - "However this dissolved plutonium undoubtedly would be slowly redistributed in the lung in the same fashion as that reported by Moskalev +) for inhaled soluble compounds of plutonium, resulting in a highly non-uniform distribution, with hot spots located predominantly in the sub-pleural region of the Lungs." Comments: That "...this dissolved plutonium undoubtedly would be slowly redistributed in the lung...''-(emphasis added) is a source of confusion. The material that is redistributed in the lung is the material that does not become solubilized, e.g., Pu0) particles, or polymerized Pu(NO3)4. The solubilized plutonium enters the bloodstreams and is translocated to the liver or the skeleton; this has been shown quite clearly in both the rat and the dog in studies at the Pacific Northwest Laboratories.