638 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



10' 



10' 



2 102 



O 



Q. 



10 



1-2 



Experimental: After After 



2 days 5 days 



Whole duck O • 



Duck without gut D ■ 



Gut and contents A A 



Fig. 4 Total plutonium accumulated by experimental ducks after 2 and 5 days of 

 continuous contact with U-Pond compared with minimum, maximum, and mean 

 concentrations of plutonium in whole waterfowl occurring naturally on U-Pond. Mean 

 plutonium concentrations in experimental ducks are shown by location of appropriate 

 symbol within the ranges of data depicted by horizontal lines. 



indicates that most of the plutonium accumulated while the ducks were in contact with 

 the pond would be lost soon after they flew away. 



The mean plutonium concentrations of whole experimental ducks after 2 to 5 days of 

 continuous-contact with U-Pond (~6 X 10° pCi/g) were more than an order of magnitude 

 greater than the mean plutonium concentrations in whole wild duck samples (~4 X 10~ ^ 

 pCi/g, Fig. 4). However, the maximum plutonium concentrations in whole wild ducks 

 were higher than the minimum concentrations in whole experimental ducks. This 

 comparison suggests an upper limit of contact duration, and it is concluded that wild 

 ducks have a plutonium burden that is less than that obtained from 2 days of continuous 

 contact with U-Pond. 



The estimated total weight of waterfowl contacting U-Pond annually is 1.2 x 10^ kg. 

 Since the range of plutonium concentrations in whole wild ducks was from 3 X 10~^ to 

 3x10° pCi/g, the amount of plutonium exported by waterfowl annually could be from 

 approximately 4 x 10^ nCi to 4 x 10^ nCi. The mean plutonium concentration in whole 

 wild ducks of 4 X 10"^ pCi/g suggests a mean annual export of 5 x 10^ nCi of 

 plutonium. These export quantities are approximately four orders of magnitude lower 

 than the total plutonium inventory for U-Pond. 



Birds. Birds observed around U-Pond are mainly sparrows, swallows, blackbirds, doves, 

 and shorebirds (Emery, Klopfer, and Weimer, 1974). Estimates of contact frequency 



