Biological Effects of Transuranic Elements 

 in the Environment: Human Effects 

 and Risk Estimates 



ROY C. THOMPSON and BRUCE W. WACHHOLZ 



The potential for human effects from environmentally dispersed transuranic elements is 

 briefly reviewed. Inhalation of transuranics suspended in air and ingestion of transuranic s 

 deposited on or incorporated in foodstuffs are the significant routes of entry. Inhalation 

 is probably the more important of these routes because gastrointestinal absorption of 

 ingested transuranics is so inefficient. Major uncertainties are those concerned with 

 substantially enhanced absorption by the very young and the possibility of increased 

 availability as transuranics become incorporated in biological food chains. 



Our knowledge of plutonium distribution and retention in the human is based on 

 human autopsy data and on the extrapolation of a large body of experimental animal 

 data. These data are undoubtedly more precise than our knowledge of the environmental 

 exposure pathways that may lead to such deposition and more precise than our 

 knowledge of the health consequences that may result from this deposition. 



There is no positive information on the effects of transuranic elements in either man 

 or experimental animals at the very low exposure levels with which we are concerned. 

 Various approaches to the evaluation of this problem are discussed. We can conclude with 

 some certainty that effects from present fallout levels will never be detected as a 

 perturbation on normal cancer death rates. The possibility of no cancer deaths from 

 fallout plutonium cannot be precluded. 



The principal focus of this book is the environment, exclusive of man. Our ultimate 

 concern, however, is for the effect of this environment on man. This chapter, therefore, 

 reviews briefly the routes by which man can interact with transuranics in the environment 

 and the possible consequences to man of such interaction. The level of treatment in this 

 chapter is less detailed than in other chapters. The reader interested more specifically in 

 effects on man and in the animal studies bearing on that problem can find such detail in 

 several recent compilations: Hodge, Stannard, and Hursh, 1973; Bair, 1974: Thompson 

 and Bair. 1972: Jee, 1976; and Wachholz. 1974. 



Routes of Exposure 



Opportunities for exposure of man to transuranics are of two quite different types: those 

 resulting from employment in the nuclear industry and those resulting from the general 

 dispersal of transuranics throughout the environment. It is the latter type which concerns 

 us in the context of this book. Routes of exposure will differ for the two types, but 

 effects are presumed to be similar in both cases. 



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