PLUTONIUM CONTENTS OF FIELD CROPS 393 



TABLE 4 Plutonium Concentration and Concentration 

 Ratio of Field Crops from the Oak Ridge WOC Floodplain 



* Values are means ± 1 standard error, which includes analytical 

 error of approximately 10%. 



fConeentration ratio values are based on a soil concentration of 

 63 + 0.4 (standard error) pCi/g. 



because no particles were observed in microscopic examination on any sample except 

 soybean pods where hirsute structures effectively retained surface contaminants. 



The plutonium concentration of soybean fruit, which included the pod, was similar to 

 that of the whole bean. Concentrations of whole snap beans and shelled beans were also 

 similar. For both species the bean pod protected bean seeds from possible surface 

 contamination while young bean seeds matured on the vine. Because plutonium 

 concentrations were similar when bean seeds were analyzed separately and when seeds 

 and pods were analyzed together, these observations reinforced the argument that any 

 residual surface soil contaminant was removed from vegetative surfaces by the cleaning 

 process. Thus the plutonium content of these vegetables is attributed to assimilation by 

 the root pathway. Other results in support of root assimilation are discussed elsewhere 

 (Dahlman, Bo.ndietti, and Eyman, 1976; Dahlman and McLeod, 1977). 



