elfen he bess P15 to ow dete is cbhtaimed upon assuming Saab 60-75% of the fallout is due to Russian tests having a storage time of 6 te 9 months with the remainder coming from Pacific tests vith a storage time of 4 years. This proportbionabion appsaved to eonbinus throvghow: the summer of 2959. On this besis it is possible to compute the initial amomt of any isotope in the resevolr at the time of detonation. For exemple, Sze Csvb? eontent of the ressvoir according to these data yas 6.0 megecuries in Cctober 1958. For thia same date, sir and rain sapling indicated 4 megeeuries of Sr? in the resevoir (13). Using the Cs/Sr ratio of 1.6, one obteins 6.4 megacuries of ca’. The initial resevoir content of the other fiegion vroducts measured are in agreement with that of cel?” secording to the fission yielés of thege isotopes. Encouraged by the consistancy of these findings, estinates of the future levels of external radiation and integral dose from such radiation wers mats under the assumption that testing is not resumed. T% is to be emphasized that these figures actually vertain only to the Argorme site and ite immediate surromdings, although the similarity in Sr70 deposition at Argonne and at other localities throughous the North Central and Northeastern United States implies that comparable fallout levels sxist over this area, which contains roughly one half the population of the country. Figure 2? indicates the variation of gamma dose rate from ali fission products, as well as that due to ce? alone, starting in 1957, Extrapolation to future levels is doze

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