OFFICIAL USE ONL. emitters unless the levels were very high. At present there are 250 square miles of the Nevada Test Site contaminated with "significant" amounts of plutonium. An applied ecology group has been formed at the test site which is supported both by the Division of Biology and Medicine and the Division of Military Application. In addition, there are representatives from a number of other agencies on the steering committee. The steering committee An ad hoc committee provides guidance on priorities of research activities. on plutonium has been established to recommend research approaches to the plutonium problem. The plutonium problem is considered to have a high priority. Studies by this group are confined to the Nevada Test Site. The Environmental Protection Agency is looking at areas outside the boundaries of the test site. The work to date indicates that plutonium contamination is 3-7 times higher under the brush that grows on the desert floor than it is on the desert floor. The old surveys were made between the stands of brush and therefore underestimated the extent of contamination. Mr. Davis described in some detail some of the proposed work which involves many organizations and many disciplines. Basically they will be looking at the distribution over the surface of selected areas of the test site, the distribution with soil depth, the amounts in the native animals and in the plants growing in these regions, Dr. Vaughan, from the Battelle Northwest Ecology group, discussed "reentrainment" of plutonium in ecosystems through biological factors. He suspects that chelation plays an important role in the reentrainment phenomenon. They have found that plants growing around fuel processing installations show a higher level of plutonium than they would have expected. Because of the strong discrimination against plutonium when it is ingested, he suggested that the body burdens found in animals in contaminated areas may result from respiration of the material rather than its ingestion. Dr. Lindenbaum, from the Argonne National Laboratory, discussed his experiments in small animals using plutonium and americium. The materials were given by injection rather than by the respiratory route and the measurements made were concerned primarily with distribution and excretion of these nuclides. He tried various proportions of colloidal plutonium in the injected solutions and found that the greater the percentage of colloid, the higher the retention in the liver as opposed to bone. Later, however, the material deposited in the liver moves to the bond endosteum. Like many investigators before him, he found that chelating agents are usefuly in removing either of these materials from the liver. The loss in the chelated form is through the biliary system. He is of the opinion that 20 nanograms of plutonium per gram of liver is a threshold for killing of the liver cells which then enables translocation to bone. Chelation is not useful in removing radionuclides from bone. He indicated that they plan to extend their studies to dogs. They also plan to try to utilize "glucan" to remove radionuclides from the reticulo- endothelial system. If chelation is used in conjunction with glucan, apparently there is significant excretion through the urinary tract. then Dr. W. Jee, from the University of Utah, described the research in dogs that has been conducted there. This was the first laboratory established OFFICIAL USE ONLY