sone tol atBS PaiBIRba St a aetik hs Sa Da abd Contamination from Local Fallout tnity «table 5). The largest portion (99 per cent) of the internally deposited activity was fixed m the skeleton. The biological localization of residual activity within skelctal tissue is shown in an autoradiograph of the femur of a pig that was exposed to the initial fallout for a period of 30 davs following detonation (figure 2}. It will be noted that there 1s a dense concentration of fission products in the eprphvscal region of the bone. For comparison. the autoradiograph of a tibia of a rooster collected at 2 vcars following detonation is shown in figure 3. Here 1s seen a concentrated deposition of activity in the draphysis and a hghter deposition in the region of growth at the ends of the bonc. indicating that the primary deposition occurred soon after detonation. while the ammal was \oung and growing. and that subsequent bone growth incorporated much smaller amounts of radivactive material. Ficure 2, Autoradiograph of femur of Ronzelap pig; sacrificed 38 days after detonation (from Cohn, 1956). o042 151 317