68 EFFECTS OF IONIZING RADIATION Table 5.1.—Biologically Hazardous Internally Deposited Fission Products Hawr-Lire RabDIo-ELEMENT Treetor RaDIaTION Piston ABUNDANCE ~ Sr yu 8 8 Ze Rus Rui By Bey a Bal By [3st Lai Celt Pris Celt 8, 8 8,7 a 8, ¥ | | ! | 4.6 | 6.4 3.7 05 | | 690 | 5.4 | 5.9 28 6.0 5.7 5.3 FRACTION REACHING CRITICAL 7 | | | aes 538 387 65 42 365 8 | 7 5 5Davs By INGgstion | 3.9 x 108 | | 13.8 | 275 25 | . 35 04 04 | . 07 | 0. 22 >500 28x10 ' 0.14 180 0.2 0.15 > 100 20 20 12.8 | ~ 200 17 | 2 86| Toe 35 =>100 50 500 | . 20 12x 107) . 25 01 2x 10-4 0. 10 1.3x10-* | , 063 From: ' Seaborg and Perlman, Rev. Mod. Physies, 20: 585, 1948. ? Hamilton, J. G. Rev. Mod. Physics, 20:718, 1948. 3 Handbook 52, U. S. Dept. of Commerce, National Bureau of Standards. general, long radiological and biological halflives and produce high-energy beta particles. Thus, they cause greater damage to bone and to the radiosensitive bone marrow than to other tissues. The damage to the blood formingtissue results in a reduction of blood cells, and thus affects the entire body. Information on the biological effects of internally deposited isotopes is derived from the limited studies of accidental radioisotopic poisoning in humans, or from animal experimentation. The best documented data on theeffects of small amounts of internally deposited emitters in human beings are obtained from studies of radium poisoning. .\s a result of radium deposition, terminal anemia, bone necrosis and osteogenic sarcoma appeared after a numberof years. The residual activity in the body associated with these effects is 1 to 2 micrograms of radium. Radium is a particularly hazardous element when deposited internally because of its long biological and radiological half-life. Very few data are available on the long term biological etfects in humanbeings of the shorter lived isotopes such as Sr, I, P® and Na*. The metabolism, excretion and biological effects of a number of fission products have been studied in animals by Hamilton (1), .\brams (2), Bloom (3). However, most of these studies do not cover the problem of the long term effects in animals produced by small amounts of internally deposited isotopes. Fewdata are available concerning the effects of internal contamination with mixed fission preducts from nuclear detonations. Contamtnation is not produced by every cletonation of a nuclear device. For example, no internal contamination was detected in individuals exposed to the air burst at Nagasnki and Hiroshima. . In Held tests of the contaminating type of atoniic detonation, animals that inhaled fission products during short periods of exposure were found to have insignificant amounts of internal contamination, The long term etfects (primarily malignant changes) resulting from radium deposition have been used to set the limits for maximum permissible body concentrations of a few bone seeking radioisotopes-in the body (5). Maximum permissible body content of other radioisotopes are estimated on quantities resulting in a dose of 03 rem per week to the tissue of highest concentration,