TABLE 3. #1 SOURCES OF FALLOUT RADIATION Radionuclide Halflifes’ Years Principal Radiations®/ bs cf MeV MeV A_f Cesivm-137 30 - 0.187 Strontium 90 29 - | 24,065 Plutonium -239 -240 " Americium -241 eds F Fraction absorbed from gut in adults*/ Annual dose (ren) per pCi/g in tissuef/ soft tissue bone marrow MeV .66 1.0 -010 (muscle) -009 1.13 - 3 - 005 5.23 - - -001 1.93 0.63 6,537 5.24 - - .001 1.93 (liver) 0.63 432 5.57 - .001 “/ ICRP Publication 38. b/ Quality factor, 20. c/ Quality factor, 1. - (liver)| 2.06 (liver) 0.68 (Radionuclide transformations) 4/ X and gamna rays are anitted whose total contribution to dose would be less than 16%. ¢/ ICRP Publication 30. Supplement to Part 1. (1980), and ICRP Publications 48 and 5] for transuranics. transuranics. The half-retention time in liver is 20 years, in skeleton 50 years for the t/ Dose in 1 year for an activity of 1 pCi/g maintained for that year in the tissues which receive the highest dose when the radionuclide is ingested. (Reference, See Footnote */.) 21