600 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



this region of the lagoon are variable, and the windward reef community contributes a 

 significant detrital load with associated plutonium to the lagoon. Since growmg coral is a 

 point source in the environment, small changes in even the local circulation, to name one 

 of many factors, will greatly alter the plutonium concentration in the vicinity of the 

 coral. It is rather more surprising that, for the most part, the ^'^^ ^'*°Pu levels associated 

 with the last 9 yr of growth are nearly constant. This shows that the dissolved 2 3 9+2 4 Op^ 

 levels available to the corals in a specific region have also been similar during the last 9 yr. 

 These results from coral and other studies demonstrate that Enewetak lagoon has 

 attained a chemical steady-state condition with respect to plutonium remobilization from 

 solid components to solution. Not only will the simple equiUbrium model explain average 

 concentrations in lagoon water but also it can be used to estimate local concentrations 

 expected in the waters from areas of the Atoll with different levels of contamination. By 

 using appropriate concentration factors for plutonium, one can estimate the quantities 

 accumulated by marine organisms anywhere in the lagoon. The data on biotic 

 concentration can be used to estimate the potential dose to man if part or all of the Atoll 

 were to supply his marine food requirements. 



Acknowledgments 



I wish to express my appreciation to several coworkers, K.Wong, R.Eagle, R. Spies, 

 K. Marsh, T. Jokela, J. Brunk, G. HoUaday, and L. Nelson, who provided much of the 

 previously unreported data and without whose efforts in the field our program in the 

 Marshall Islands could not be carried out. This work is supported by the Division of 

 Biology and Environmental Research of the U. S. Department of Energy, contract No. 

 W-7405-ENG-48. 



References 



Beasley, T. M., 1976, Analysis of Windscale and Bikini Atoll Sediments for ^''^ Am, in Activities of the 

 International Laboratory of Marine Radioactivity 1976 Report, Report IAEA-187, International 

 Atomic Energy Agency, Vienna. 



Bowen, V. T., H. D. Livingston, and J. C. Burke, 1976, Distributions of Transuranium Nuclides in 

 Sediment and Biota of the North Atlantic Ocean, in Transuranium Nuclides in the Environment, 

 Symposium Proceedings, San Francisco, 1975, p. 107, STI/PUB/410, International Atomic Energy 

 Agency, Vienna. 



CLrceo, L. J., Jr., and M. D. Nordyke, 1964, Nuclear Cratering Experience at the Pacific Proving 

 Grounds, USAEC Report UCRL-12172, Lawrence Livermore Laboratory, NTIS. 



Duursma, E. K., and P. Parsi, 1974, Distribution Coefficient of Plutonium Between Sediment and 

 Seawater, in Activities of the International Laboratory of Marine Radioactivity 1974 Report, 

 Report IAEA-163, p. 94, International Atomic Energy Agency, Vienna. 



Emery, K. O., J. L Tracy, and H. S. Ladd, 1954, Geology of Bikini and Nearby Atolls, Professional 

 Paper 260-A, U. S. Geological Survey. 



Gatrousis, C, 1975, Lawrence Livermore Laboratory, private communication. 



Gerber, R. P., and N. Marshall, 1974, Ingestion of Detritus by the Lagoon Pelagic Community at 

 Enewetak AtoW, Li mnol. Oceanogr., 19: 815. 



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

 ¥[\i\.om\\m. Nature , 241: 444. 



Hetherington, J. A., D. F. Jefferies, and M. B. Lovett, 1975, Some Investigations into the Behaviour of 

 Plutonium in the Marine Environment, in Impacts of Nuclear Releases into the Aquatic 

 Environment, Symposium Proceedings, Otaniemi, Finland, 1975, p. 193, STI/PUB/410, Interna- 

 tional Atomic Energy Agency, Vienna. 



Hines, N. O., 1962, Proving Grounds, An Account of the Radiobiological Studies in the Pacific, 

 1946-1961, University of Washington Press, Seattle, Wash. 



