430 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



10^ 



5 10^ 2 5 102 2 



DEPTH (D), cm 



5 10-^ 



Fig. 5 Rutonium concentration in Rocky Flats macroplot 1 soil as a function of depth 

 of sample. Sample concentrations adjusted for distance east and south of center of 

 asphalt oil-barrel storage pad. 



composition of the soil sample. The spatial distribution of plutonium (i.e., more 

 plutonium downwind than downslope) implicated wind as the prime mechanism of 

 plutonium transport onto the studied areas. Such factors as resuspension with or without 

 added mechanical disturbances by humans or fauna undoubtedly contributed to the wind 

 transport of plutonium but to a presently unknown degree. The data also indicated that 

 plutonium was found to a depth of 21 cm in most samples from downwind of the barrel 

 storage area but that about two-thirds of the contamination was in the top 5 cm. The 

 relationship between plutonium concentration and soil particle size suggested a 

 surface-attachment mechanism of plutonium attacliment to soil particles. However, the 

 lack of any pattern of soil mass fraction with depth for the various particle sizes probably 

 indicates that plutonium transport with depth is not simply a case of transport of the 

 various plutonium— soil particles downward. 



Plutonium in Plant Compartments 



The vegetation community of the study area was composed mostly of grasses and 

 members of the sunflower family. Members of the sedge, pea, and mustard families were 



