TRANSURANICS IN MARINE ENVIRONMENT 715 



fraction of the transuranics produced has been or will be released or disposed of to the 

 environment. We still, however, have only a scant knowledge of the processes that control 

 the behavior and fate of the transuranics in the environment, and hence our abihty to 

 predict and assess the potential effects is hampered. 



In the past, and this is still partly true today, the primary consideration has been 

 anthropocentric, and research priorities have been particularly directed to the assumed 

 primary pathway of inhalation by man. Less attention has been given to secondary 

 pathways, wliich result in chronic long-term exposures to man through the food web and 

 to biota in the ecosystem. Although the primary short-term hazard to man from an 

 atmospheric release may be via the inhalation pathway, it behooves us to give increased 

 consideration to the long-term hazard potentials because of the potential time lag in 

 transfer and long-term persistence in natural reservoirs. 



The behavior and fate of transuranics in the marine environment were given very little 

 attention before the mid-1960s. One reason for this was the lack of methodology and 

 instrumentation to determine the ultralow levels that existed in the aquatic environment. 

 In fact, it was not until Pillai, Smith, and Folsom (1964) determined the levels of 

 2 3 9,2 4 0p^j -j^ marine organisms from weapons tests that any data were published other 

 than total-alpha measurements from some selected sites. Since that time data have 

 become available for plutonium isotopes and americium from weapons tests, SNAP -9 A, 

 and some reprocessing plants in particular in air, freshwater, seawater, sediment, and 

 biological materials. Much of the available published data was reviewed by Noshkin 

 (1972). Although intensive monitoring and research studies have been conducted more 

 recently at the Pacific test sites (U. S. Atomic Energy Commission, 1973), in the 

 northeast Irish Sea (Hetherington et al., 1976), at La Hague in France (Frazier and Guary, 

 1976; Guary and Frazier, 1977a; 1977b), and in Lake Michigan (Wahlgren et al., 1976), 

 by far the greatest amount of data on plutonium isotopes generated in the late 1960s was 

 applicable only to the determination of the residence times of these materials in the 

 oceans. Laboratory and field studies on plutonium kinetics in marine ecosystems have 

 been very limited until recently, and even today Httle research has been conducted on 

 transuranic elements other than plutonium (International Atomic Energy Agency, 1976). 

 Data for americium, neptunium, and curium are sparse, and none have been published for 

 berkelium and californium. This chapter discusses one aspect of transuranics in the 

 marine environment: the potential effects of radiation from these materials on organisms 

 in the marine ecosystem. 



One way to assess whether the present levels of transuranics, more particularly 

 plutonium, in the aquatic environment have a potential to result in somatic or genetic 

 damage to aquatic organisms is to compare the radiation dose rate from plutonium, both 

 from weapons-test fallout and from selected sites contaminated to a relatively higher 

 level, with that from natural radiation to which organisms, populations, communities, and 

 ecosystems have been exposed for near- geological time for their life-spans. These 

 calculated dose rates can also be compared with experimentally determined data on 

 effects. Finally, where the availabiUty of data for the latter are lacking, we need to assess, 

 and perhaps hypothesize, on the basis of other related data on radiation effects, 

 ecological interactions, and population dynamics, whether or not these dose rates in the 

 environment could result in somatic and genetic effects that would be detrimental to the 

 maintenance of aquatic populations. This chapter draws heavily on a recent review and 

 assessment of the ecological effects of radiation in the marine environment (International 



