Dosimetry and Ecological Effects 



of Transuranics in the Marine Environment 



WILLIAM L. TEMPLETON 



Radiation doses received by aquatic organisms as a result of exposure to transuranics in 

 the ertvironment are comparable to those received from natural radionuclides even in 

 known contaminated areas. At these levels it is doubtful whether experimental studies in 

 the field, or in the laboratory at similar levels, could reasonably be conducted which 

 would offer some degree of success in determining radiological effects on individuals, 

 populations, or ecosystems. Some of the mechanisms of recruitment to exploited fish 

 populations are considered, and these mechanisms suggest that any radiation-induced 

 effects would probably be compensated for by density-dependent responses in highly 

 fecund species. In species with low fecundity, increased stress would clearly increase the 

 chances of diminishing these populations; however, from the dose-rate estimates, present 

 levels of radiation are unlikely to provide any additional stress in comparison to 

 exploitation of some of these species by man. Although little quantitative genetic 

 information is available for aquatic populations, it appears unlikely, from estimated 

 mutation rates, that significant deleterious genetic effects due to radiation would be 

 produced at the present low levels in the environment. 



Over the past quarter of a century, the open oceans and coastal waters of the world have 

 received quantities of artificially produced transuranic elements. These elements have 

 been distributed globally in the atmosphere as a result of nuclear weapons testing 

 conducted by the United States, the United Kingdom, the Union of Soviet Socialist 

 Republics, France, India, and China and the burnup of a U. S. space sateUite (SNAP-9A) 

 in 1964. Estimates are that about 325 kCi of ^^^'^"^^Pu and about 8 kCi of "^Pu have 

 been deposited over the globe by weapons testing and about 1 7 kCi of ^ ^ ^ Pu by the SNAP 

 failure (Hardy, Krey, and Volchok, 1973). On a more local scale, transuranic elements 

 have been, and continue to be, introduced to the marine environment at nuclear weapons 

 testing grounds, at nuclear-fuel reprocessing plants, and, to a much lesser degree, by 

 nuclear power facilities and occasional nuclear-device accidents. In the Pacific the total 

 inventory of transuranic elements in the, Bikini and Enewetak atolls at the Pacific Proving 

 Grounds probably is as high as 10 kCi, with a reported net flux from the Bikini lagoon to 

 the North Equatorial Current of about 6 Ci of ^^^'^"^^Pu per year and 3 Ci of ^'** Am 

 per year (Nevissi and Schell, 1975). During the period 1960 to 1974 (Hetherington et al., 

 1975; 1976), the nuclear-fuel reprocessing plant at Windscale (United Kingdom) 

 discharged approximately 10 kCi of ^^^'^^^'^''^Pu to the northeast Irish Sea. In recent 

 years the average transport out of the Irish Sea has been 40 Ci/yr. 



The major world inventories of transuranics are, of course, contained in reactors, 

 weapons stockpiles, reprocessing plants, and waste-storage systems, and only a very small 



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