activity is 2.6% of the initial atl activity. Because the present 241 Pu activity in the soil is about seven times that of 2??+240 Pu, the final 241A soil activity resulting from the decay of 7+! pu will be 0.18 that of concentrations are 0.7 that of 241 Am resulting from 24) 23942405 2394240 Pu. The currently observed 241 Ay soil Thus, the final total soil concentration of 241 Am now present and that resulting from 0.88 (0.7 + 0.18) that of the existing 727*2#0 Pu soil concentrations. Pu decay will be For estimates of dose via inhalation, the eventual 241 Am soil concentrations can be considered equal to the 23942405, concentrations. As a result, the doses calculated for 239+240p, can be doubled to account for the 24! am, 102 T 7 T TT F \ ba L Zz = 10-¢ F 2 C = T TFT “Ty T T T 7 241 by activity 7 \ 4 \\ \ 4 \ \\ sfL 2 \ z4 a \ ‘\ & 26 — poe eof 1 : 241 am activity _ \ \ 1 \ z \ q 241 Puactivity .. 4 1 241 Am activity 0.1 pop gt 0 4 tt a 40 80 7 S f \ 120 Time (y) Figure 2. Relationship between parent aul Pu activity and daughter 241 amy activity. 1D