TRANSURANIC AND TRACER SIMULANT RES USPENSION 251 



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— Site AB 



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 filter 



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10 100 



PARTICLE DIAMETER, Mm 



1000 



Fig. 11 Plutonium-239 concentration on airborne soil as a function of particle diameter 

 at Rocky Flats. 



Both ^^^Pu and ^^^Pu concentrations on airborne soil decreased from site A to 

 site AB. Site AB/site A ratios are shown in Fig. 13. Concentrations per gram decreased by 

 a factor of up to about 10"^ in the intervening 392-m distance separating sampling 

 sites A and AB. Concentration ratios for ^''^Pu on respirable particles were about 10~^ 

 and were independent of particle size. In contrast, for nonrespirable particle sizes "^^^Pu 

 ratios between sites decreased nearly linearly as the particle diameter increased. 

 Plutonium-239 concentrations on nonrespirable particles decreased at rates greater than 

 those for the ^^^Pu concentrations. For ^^^Pu the concentration ratios for 

 site AB/site A were nearly one order of magnitude greater than for ^^^Pu. These larger 

 ratios suggest that ^^^Pu resuspended more readily relative to ^^^Pu. 



