25. "Deposition and Retention Models for 1966. Task Group on Lung Dynamics. Internal Dosimetry of the Human Respiratory Tract." Health Phystce 12:173-207. 26. 27. 28, Volchok, H. L., R. Knuth, and M. T. Kleinman. 1972a. Fraction of Plutonium at Rocky Flats." 1972b. "The Respirable Health Physics 23:395~-396. 1976. Wahlgren, M. A., J. J. Alberts, D. M. Nelson, and K. A. Orlandini. Home logues “Study of the Behavior of Transuranics and Possible Chemical in Lake Michigan Water and Biota." In: Transurantuwn Nuclides in the Environment. IAEA~-SM-199/44, Vienna. p- 9-24. LOS ALAMOS WASTE DISPOSAL SITE "Plutonium in the Neighborhood of Rocky Flats, Colorado: Airborne Respirable Particles. pp. 12-117. HASL-246. Health and Safety Laboratory, New York. Volchok, H. L., R. H. Knuth, and M. T. Kleinman. DISTRIBUTION OF PLUTONIUM AND AMERICIUM AT A FORMER S. Fried, A. M. Friedman, J. Hines Chemistry Division, Argonne National Laboratory, Argonne, IL G. Schmitz Prairie State College, Chicago Heights, IL and M. Wheeler Los Alamos Scientific Laboratory, Los Alamos, NM ABSTRACT A thirty year old liquid waste disposal site at Los Alamos Scientific Laboratory has been cored and a portion of each six inch increment analyzed for plutonium and americium. The site received unprocessed tow level waste solutions from 1945 to 1952, and treated waste effluents from 1952 to 1967. The actinide content of each core increment was determined by low energy photon spectroscopy utilizing the characteristic L x-rays of each nuclide. The data obtained are presented as a histogram and compared to gross activity measurements made at the site. A laboratory simulation of the site was also prepared using simulated waste solutions and a specimen of disposal site's geologic material, tuff, a welded volcanic ash. This simulation was scaled and proportioned according to archival records of the original site. The results of this experiment are compared with measurements from the actual core sample. INTRODUCTION One of the most serious problems confronting the nuclear energy industry is the long term isolation of radioactive wastes, Transuranic elements contained in such waste contribute significantly to the hazard, both in toxicity and persistence. Whatever method is finally chosen to contain these wastes, access of the actinides to the environment must be restricted. Deep terrestrial 115 114