TRANSURANICS IN TERRESTRIAL ENVIRONMENT 705 



Calculations: 



Required air concentration 



__ (lxlO-^MCi/g)(IO-'MCi/,n3) ^ , 3 ^ ,0^3 ^„/™= 

 1.6 X 10-5 ^(^j/g 



Required ^^^Pu application to soil 

 _6.3 X lO-^iuCi/m^ _ 



10-5/m 



630MCi/m^ 



If these calculations approach reality, it is clear that very large applications of ^ ^^Pu 

 would be required to produce measurable ecological changes, especially in plant 

 communities. Nevertheless, such studies, if done, would carry more credibility than crude 

 extrapolations and simplified calculations. 



Contaminated Environments 



The approach of examining ecosystems that have been accidentally contaminated with 

 transuranics is feasible and probably desirable. Because of the lack of direct experimental 

 data and the inherent complexity and uncertainty in computational models, we should 

 look at areas that have been contaminated to ^^^Pu activity levels that significantly 

 exceed worldwide fallout levels. Several such areas exist or have existed in the past. These 

 include Rocky Flats, Trinity, several areas at the Nevada Test Site, and various sites on 

 Enewetak atoll (in the Pacific). In addition, plutonium releases to the environment have 

 occurred from nuclear facilities at Oak Ridge, Hanford, Mound Laboratory, Los Alamos, 

 Savannah River, Idaho National Engineering Laboratory, and from bomber crashes in 

 local areas in Greenland and Spain. 



If sufficiently careful searches for ecological changes in contaminated areas prove to 

 be negative, then it probably can be concluded that the observed levels had no detectable 

 consequence. Such data should be examined in the light of laboratory information for 

 additional assurance. If biological perturbations are discovered in contaminated areas, 

 then it may or may not be possible to assign causal factors. In many contaminated sites, 

 more than one toxic substance may be present, or other factors may be responsible for 

 changes. It may be possible to offset these problems if a proper control area is available, 

 but this should be determined before the initiation of any search for effects. 



A comparison of various biological measurements between two ecologically similar 

 study areas of substantially differing '^^Pu levels at Rocky Flats was conducted by T. F. 

 Winsor* and C. A. Littlet of Colorado State University and G. E. Dagle of Battelle— 

 Pacific Northwest Laboratories (Whicker, 1976; Little, 1976). The ^^^Pu readings from 

 soil in the principal study areas ranged from 100 to over 20,000 d/min per gram in the 

 upper 3 cm (2 to 400 )uCi/m^). In addition, comparative data were obtained from control 

 areas containing only worldwide fallout plutonium of the order of 0.1 d/min per gram 



* Present address: Rockwell International, Rocky Flats Plant, Golden, Colo. 



t Present address: Division of Health and Safety Research, Oak Ridge National Laboratory, Oak 

 Ridge, Tenn. 



