Synthesis of the Research Literature 



R. L. WAITERS, D. N. EDGINGTON, T. E. HAKONSON, W. C. HANSON, 

 M. H. SMITH, F. W. WHICKER, and R. E. WILDUNG 



This book provides a compendium of enviromnental research related to transuranium 

 elements; this research has developed greatly over the last 5 yr. The individual chapters 

 describe studies that deal with mobility and transport in various environmental media and 

 physiographic provinces. The intent of this synthesis is to develop, from the information 

 in this book and other publications, unifying ideas and generaHzations about movement 

 of these elements through the environment to the human population. 



Chemical, physical, and biotic processes control movement of transuranic elements 

 within ecosystems. As illustrated by the conceptual model in Fig. 1, transport processes 

 are driven by wind, water, biotic, and mechanical activity. For example, wind, water, or 

 mechanical resuspension of soil and sediment can result in contamination of plant and 

 animal surfaces, and the diet of consumer organisms may therefore contain this surficially 

 deposited material. Examples of biotic transport include the movement of soil 

 contaminants associated with a grazing animal and the subsequent redistribution of this 

 material through defecation and/or death. Burrowing and grooming activities, which 

 result in contamination of the animal, are additional examples of biotic transport. 



Examples of chemical transport are the passage of soluble contaminants from soil 

 through plant roots or across physiological membranes (e.g., lungs or gut wall) and the 

 vertical leaching of soluble contaminants through the soil, although these processes may 

 involve biochemical and physical parameters. 



To predict the behavior of transuranic elements in the environment, one must 

 understand (l)the ecological relationships in contaminated ecosystems, including the 

 content and size of compartments and the exchange of materials between compartments, 

 and (2) the pathways, rates, and mechanisms of transport through the ecosystems. 



The behavior of transuranic elements in the environment must be described, at 

 present, in terms of data obtained from direct sampling of sites with different 

 contamination histories, sources, and ecological features. This information, together with 

 data from laboratory studies defining rates and mechanisms, provides the framework for 

 consideration of environmental fates and effects. 



The results of this synthesis are, in many cases, tentative conclusions — as one would 

 expect in any process involving inductive reasoning. Most of the inferences must be drawn 

 from data pertaining to plutonium, which has been more intensively studied than other 

 transuranic elements now under investigation. Some of these conclusions will become 

 well established as more evidence accumulates; others may require modification to 

 emphasize exceptions. 



