SYNTHESIS OF THE RESEARCH LITERATURE 3 7 



4. In spite of the large fraction of plutonium and americium residing in soils and 

 sediments, chemical and biological processes produce a veiy small fraction of soluble 

 species in terrestrial and aquatic environments. These species are incorporated in 

 biological tissue, but the concentrations in biota have not produced demonstrable 

 deleterious radiation effects. 



5. An increase or decrease in the soluble fraction of plutonium over long weathering 

 times cannot be demonstrated at tliis time. However, preliminary observations of 

 naturally occurring analog elements indicate that plant uptake and transfer of plutonium 

 and americium througli food chains would not be expected to change appreciably over 

 time. 



6. Concentrations of plutonium do not increase from one trophic level to the next in 

 natural food webs except for sorption by phytoplankton and one observation of starfish 

 feeding on mussels. 



7. The environmental chemistry of transuranic elements in marine and in oligotrophic 

 freshwater systems is similar in a number of ways. However, significant differences in 

 chemical species exist in many lakes where chemical conditions, such as pH and ligand 

 concentration (botli organic and inorganic), may be different. 



8. Present levels of transuranium elements in our environment have not produced 

 discernible ecological effects. 



Important reservations are implicit in the above generalizations mainly because of 

 insufficient information on fundamental processes and lack of data pertaining to 

 transuranic elements other than plutonium. Three lines of investigation are necessary in 

 future studies: 



1. Develop process and dose models as a framework to identify specific research areas 

 where important data are lacking. 



2. Expand research related to neptunium, americium, and curium to provide a 

 broader base of information about the environmental behavior of the transuranic 

 elements. 



3. Investigate the kinetics of the Pu(IV)^Pu(V and VI) oxidation and the factors 

 controlling tliis valence distribution since increasing evidence suggests that oxidation 

 mechanisms occur that make plutonium more soluble than predicted in some environ- 

 mental media. 



References 



Adriano, D. C, et al., 1975, A lield Study to Determine Pu Contents of Wheat and Soil in a Warm, 

 Humid Area, in Annual Meeting of the Society of Agronomy, Knowille, Tenn., Aug. 24-29, 

 1975. 



Alberts, J. J., R. N. Muller, and K. A. Orlandiiii, 1976, Particle Size and Chemical Phase Distribution 

 of Plutonium in an l-,stuarine Sediment, in Radiological and Environmental Research Division 

 Annual Report. January-December 1976, ERDA Report ANL-76-88(Pt. 3), pp. 34-36, Argonne 

 National Laboratory, NTIS. 



Anspaugh, L. R., J. H. Shinn, and P. L. Phelps, 1915, Resuspension and Distribution of Plutonium in 

 Soils, USAEC Report UCRL-76419, University of California Radiation Laboratory, NTIS. 



, J. H. Shinn, and D. \V. Wilson, 1974. Evaluation of the Resuspension Patliway Toward Protective 



Guidehnes for Soil Contamination with Radioactivity, in Population Dose Evaluation and 

 Standards for Man and His Environment. Symposium Proceedings, Yugoslavia, May 20-24, 1974, 

 pp. 51 3-524, STl/PUB/375, International Atomic Energy Agency, Vienna. 



^ J. H. Shinn, P. L. Phelps, and N. C. Kennedy, 1975, Resuspension and Redistribution of 



Plutonium in Soils, in Proceedings of tlie Second Annual Life Sciences Symposium on 



