258 TRANS URANIC ELEMENTS IN THE ENVIRONMENT 



< 



en 



CL in-l 



10" 



O 



GO 

 EC 



Site B 



Site AB 



10" 



200 400 600 800 



DISTANCE FROM SITE A, m 



1000 



Fig. 16 Ratio of ^^'Pu/^^'Pu on nonrespirable airborne particles as a function of 

 distance at Rocky Flats. 



calculated from these data may be more representative than ranges calculated for ^^^Pu. 

 The ^^''Cs data for the BC-Crib Area ranged from 10"^ to 30. The magnitude of this 

 range is important since one might as a first approximation assume air contamination 

 levels per gram of solids to be equal to surface contamination levels per gram of solids. 



Airborne ^ ^ ^Pu/^ ^ ^Pu Ratios 



Airborne ^^^Pu/^^^I*u ratios at Rocky Flats consistently changed (Sehmel, 1976a) from 

 sampling site A to site B. Ratios shown in Fig. 16 are for total plutonium collected within 

 each cowl at each sampUng site and sampling height. At site A the ^•^^Pu/^'^^Pu ratio on 

 airborne nonrespirable soil is comparable with ratios determined from 5-cm-deep 

 surface-soil samples. The surface-soil range is shown as the crosshatched soil sample range. 



