90 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



does not exceed 400 Ci, of which a small percentage may have reached the general off-site 

 environments. 



Something should be said v^th regard to the ingrowth of americium as a result of the 

 decay of plutonium. During the production of weapons-grade plutonium in a reactor, a 

 small fraction of the material produced is ^'*^Pu, which has a 13-yr half-life for decay 

 by beta emission to ^"^^Am. As this decay progresses, the americium activity grows to 

 approach the long-term level. Through this ingrowth mechanism the inventory of 

 environmentally available transuranic material has substantially increased. Because the 

 percent ^'*^Pu produced depends on the conditions under which the material was 

 produced in the reactor, the amount of ^"^^ Am that will result from the ingrowth process 

 is not a fixed fraction that can be predicted. For plutonium more than 20 or 30 yr 

 after its production, however, americium activity at several percent of the curie level of 

 the host plutonium is to be expected. 



In summary, on the order of 10^ Ci of weapons plutonium has probably been broadly 

 distributed wdthin the world environment from all sources. Of that amount, between 10^ 

 and 10** Ci is probably concentrated in surface soils around the U. S. test sites. Plutonium 

 that remains dispersed and environmentally available from actual weapon accidents may 

 be on the order of 10^ Ci with perhaps an additional 10^ Ci dispersed and environmen- 

 tally available as a result of weapon accident tests. On the order of 10^ Ci of plutonium is 

 probably accessible in the environment owing to spills and releases at laboratories and 

 plants. 



References 



Carter, M. W., and A. A. Moghissi, 1977, Three Decades of Nuclear Testing, Health Phys., 33: 55-71. 



Dunaway, P. B., and M. G. White, 1974, The Dynamics of Plutonium in Desert Environments, Nevada 

 Applied Ecology Group Progress Report as of January 1974, USAEC Report NVO-142, Nevada 

 Operations Office, NTIS. 



Edgington, D. N., M. A. Wahlgren, and J. S. Marshall, 1976, The Behavior of Plutonium in Aquatic 

 Ecosystem: A Summary of Studies on the Great Lakes, in Environmental Toxicity of Aquatic 

 Radionuclides: Models and Mechanisms, Proceedings of the 8th Rochester International 

 Conference on Environmental Toxicology, Rochester, N. Y., June 2— 4, 1975, M. W. Miller and 

 J. N. Stannard (Eds.), pp. 45-79, Ann Arbor Science Pubhshers, Inc., Ann Arbor, Mich. 



Essington, E. H., and E. B. Fowler, 1976, Distribution of Transuranic Radionuclides in Soils, in 

 Transuranics in Natural Environments, Symposium Proceedings, Gathnburg, Tenn., Oct. 5-7, 

 1976, M. G. White and P. B. Dunaway (Eds.), ERDA Report NVO-178, p. 41, Nevada Operations 

 Office, NTIS. 



Glasstone, Samuel, 1962, The Effects of Nuclear Weapons, Appendix B, U.S. Atomic Energy 

 Commission, GPO. 



, and Philip J. Dolan, 1977, The Effects of Nuclear Weapons, Sec. 9.50, U.S. Department of 



Defense and U. S. Department of Energy, GPO. 



Hardy, E. P., P. W. Krey, and H. L. Volchok, 1973, Global Inventories and Distribution of Fallout 

 ?\\iXom\xm, Nature, 241: 444. 



Harley, J. H., 1971, Worldwide Plutonium Fallout from Weapons Tests, in Environmental Plutonium 

 Symposium Proceedings, Los Alamos, New Mexico, USAEC Report LA-4756, Los Alamos 

 Scientific Laboratory, NTIS. 



Meyers, Wm, A., and M. Lindner, 1971, Precise Determination of the Natural Abundance of ^^''Np 

 and ^^'Pu in Katanga Pitchblende,/. Inorg. Nucl. Chem.. 33: 3233-3238. 



U. S. Air Force, 1970, USAFNucl. Saf. 65(2), No. 1, Special Edition, Crested Ice. 



U. S. Atomic Energy Commission, 1974, Plutonium and Other Transuranium Elements, USAEC 

 Report WASH-1 359, NTIS. 



