Document pmV7z32BbneGeJe9QYKXpeDoa

industrial Hygiene Digest June, 1957 793 Pulmonary Effect* from Radioactive Thallium-Activated Clay Particles. H. Cember, J. A. Watson, and T. B. Grucci. Arch. Ind. Health 15, 449, 4^0 (May 1957). In experiments designed to study the biological effects on the lungs due to point sources of radiation located within the pulmonary parenchyma, the solubility of the radio active particle in the pleural fluids introduces a complicating (actor. A stable and practic ally insoluble source of radiation was produced by adsorbing thalllum-204 on montmorillonite clay and heating to 1000`C. Rats were intratracheally insufflated with an isotonic saline sus pension of this preparation with a narrow size distribution over a number of months. Histo logic examination of the tissue sections showed no damage that could be attributed to radla- tion. There was no difference between the control group and the exposed group. The dis tribution of the dose according to distance from the discrete particle is calculated. In this experiment, although (he specific activity of the particles was low, it i* significant that the chronic exposure In the immediate vicinity of the particle at a level about ten times greater- ' than the maximum permissible daily dose rate produced no observable biologic damage. 794 A Clinical Study of Radiation Cataracts and the Relationship to Dose. O. R. Merriam and Elizabeth F. Focht. Am. J. Roentgenol. Radium Therapy 77,* 759-783 (May 1957). The dose ot roentgen and gamma radiation to the lens ha* been measured for 100 cases with radiation cataracts and 73 cases which received radiation to the lens but did not develop cataracts. The probabilities of cataract (or varied doses were calculated for single and divided treatments. The higher the dose for a given duration of treatment, the shorter is the time of appearance of the lens changes and the higher the incidence of progressive opacities. The lenses of children under one year of age are the most sensitive. The usual shielding methods are ample protection from roentgen rays of 100-140 Kv. For higher voltages (200-250 kv. ) 2 mm. of lead is usually sufficient. In the entire group of 100 radiation cataracts, it is estimated that by the use of current techniques the lens opacities could have been avoided in at least 80 cases. - - Coad. from authors' summary 795 Decontamination of Irradiated Uranium by a FluqridcVoiatiiity Process, . W. J. Mecham, R. C. Lilmatainea, R. W. Kessie, and W. D. Seefeldt. Chem. Eng; Progr. 5_3, 72F-77F (Feb. 1957). A series of six pilot plant runs has been made on 10 kg. lots of uranium to demonstrate the decontamination of irradiated uranium by a process based on distillation of uranium hexafluoride. A rough distillation followed by a purification distillation gave a decontamination factor of the order of 10** (or the uranium hexafluoride product. Editor's summary 796 Engineering Aspects of the Disposal of Radioactive Wastes from the Peacetime Application* .ofNuclear Technology. J. A. Lieberman. Am. J. Public Health 47, 345-351 (Mar. 1957). The importance of developing safe methods of disposal of radioactive wastes is discussed. Present and possible disposal methods are described. Caseous and airborne particulate wastes are being bandied by methods that are described <-nd as yet do not con stitute a serious problem. The engineering of systems for handling and disposal of solid wastes has been relatively simple. Burial of such wastes under known, controlled conditions, and, in specific instances, disposal of sea have successfully and safely handled the problem, but problems will arise with expansion of the Industry. Incineration of combustible solid wastes has been practiced to a limited extent. In the case of liquid wastes, it is Important to distinguish between high-volume, low-level and low-volume, high level, waste*. The latter type constitutes the bulk of the engineering problem. The following methods are dis cussed: fixation in inert media, special separation of specific Isotopes, and direct dis charge to selected geologic formations. Each method presents a number of engineering problems. Other aspects discussed include site selection, administrative control, and changing technology. 11 206 1051 24.