0018933 mation of Sr °. - Measurements have been made to determine the existing levels at the saxrth's surface, the quantity stored in the stratcsphere, ind the deposition rate, Samples of fallout have been t1ken from the soil and vegetation, by gummed tipe and pot-type collectors on the grovnd,ard by 2ir-filter samplers at the surface and in the tropcesphers and etrstosphere (References &, 23, 39, 40, 41, 42, 43, 44, 45). Based on this work, it was estimated in the fall of 1956 that the Sr?? levels were about22 me /mi* in the midwestern section of the United States, 15-17 me/mi* for similar latitudes elacewhere and perhaps 3-4 mc/mi® for the rest of the world (References38, 39}, The totzl &.mount in the stretcspheric reservoir, if uniformly distributed over the azea of th: glche, would increase these figures by about 12 me/mi*, The deposi- tion rate of the stored material was considered to be around 10% per arnum, It was further estimzted that if these levelz were maintiined for fifteen years the concentration in the human sksleton would Es atcut 1% of the maximum permissible (Reference 24}, The quintity ci radioactivity in the storage reservoir was esti- mited by summation ef the contributions of all the bursts thrcugh Opsration abe ‘ REDWING which have deposited debris in the stratosphere, Ths available fraction ef the weapon wis determined by subtracting the lccsl 2nd intermediate fallout from the total, The intermediate: filleut is tho:ght to