MODEL FOR ESTIMATING Pu TRANSPORT AND DOSE 485 



where 76 m^/day = estimated respiration rate for a 275-kg cow (Eq. 21) 

 10~^ g(soil)/m^(air) = estimated mass-loading factor (Eq. 21 ) 



215 pCi/g = average concentration of "^^^Pu in the soil of Area 13* 



0.18 = assumed fraction of inhaled plutonium deposited in the lungs and 

 cleared with a 500-day half-life 

 2.1 kg = estimated weight of the lungs 

 X = In (2)/ 5 00 days 



Liver and muscle. The plutonium ingestion rate for a 275-kg cow can be estimated as 

 follows: 



Iv = 6158 g vegetation/ dayt X 0.1 X 70 pCi/g soil + 250 g soU/day x 70 pCi/g soil 

 = 60,606 pCi/day 



The concentration in liver for cows in the inner compound can now be estimated as 

 follows: 



^ _ (60,606 g/ day )(3 x 10'^)(0.12) 1 -e~^"^ 

 ^'•^^■- 4Jki X 



= 19.6 pCi/kg (vs. 13.7 pCi/kg, Table 4) 



where 3 X 10"^ = fraction transferred from the gastrointestinal tract to blood (Fig. 2) 

 0.12 = fraction transferred from the blood to the liver (Fig. 2) 

 4.8 kg = estimated weight of the liver 

 X = ln(2)/30,000days(Fig.2) 



Similar calculations were made for the other cases given in Table 4. The observed 

 values from Table 4 and the estimated values [pCi/kg (wet weight)] are compared below; 



pCi/kg (wet weight) 



These comparisons suggest that the model for beef cattle may be somewhat conservative, 

 but the order-of-magnitude agreement between observed and estimated values appears to 

 be good, better than might be expected, as a matter of fact. However, partial data for 



*Tlie average soil concentration m the outer compound is 70 pCi/g, but some of the resuspended 

 material in the air of the outer compound is assumed to come from the soil of the inner compound, 

 t Based on i-.q. 20 for a 275-kg cow. 



