74 TRANSURANIC ELEMENTS IN THE ENVIRONMENT 



100 



10 



E 



n 

 O 



c 

 E 

 2 0.1 



0.01 



0.001 



T 



T 



■^-llpu (based on 239,240pu using 240pu/239pu activity ratio 

 of 1.35 and 24lpij/239pu activity ratio of 63) 



2''lPu measurements made 

 at Richland, Wash. 



241 Pu (based on 239,240pu 

 using 240pu/239pu activity ratio 

 of 0.67 and 24lpu/239pu activity 

 ratio of 21 



241 Am calculated from Mike 241 Pu 

 and assuming residence half-time of 1 yr 



•241 Am calculated from 

 fallout 241 Pu assuming 

 residence half-time of 1 yr 



^.i: 



241 Am measured yearly 

 averages at Richland, Wash 



I " 



1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 



YEAR 



Fig. 9 Estimated concentrations of ^ " ' Pu and ^^ ' Am as compared with the measured 

 concentration of ^ "' Am in surface air since 1962 at Richland, Wash. 



TABLE 8 Relative Abimdance and Estimated 

 Amounts of Transuranium Elements That 

 Have Been Injected into the Atmosphere 



♦Assumes 360,000 Ci (360 kCi) ^ ' » -^ " o p^ atmo- 

 spheric injection with Mike ratios. 



t Americium-241 fomied on total decay of 



Pu. 



