#73 ot Date wnat hetieity 9 S739 ag799: % gr89°90 vy gr PCfon O? 8/27 4,800 d/m 3,560 74 32: 0.12 11/30 2974 afm 272 99 6 0.23 12/8 35,800 d/m 36,500 as 124 0,08 12/15 1,460 d/n 935 33 23 0.31 pcember 213 showed an average of 0,08 a/n/m, of which 0,02 d/m/n was7 ‘iostrontium., The strontium percentage, as for the .aircraft samples, was x ch higherthan Air samples collected on the roof at NYO during the week of expected. | a _ Sm oe —e et A l2epallo stainless steel pot was used to collect accumulaqed rainfall and dry fallout on the roof at NYO during the period of JulyJisSth to December 23rd of 1480 d/min,. of which 745 d/min. wera radiofktrontiun. Again the strontium pertantage is higher than expected, The analyses of samples taken during ths test period indicat a lover racdiostrontium content than expected, while those talen well after detonation show a relatively high radiostrontium content. Sines the ren cent high altitude measurements give the highest strontium pareentage. as will be discussed, it is probabis that fractionation has occurred, The late formation of Sr?” and sr°? compared to the life of [the fireball make it possible that they are more highly dispersed, [Tne early fallout is deficient in radiostrontium, since the smaller particles re= main suspended, while the iater fallout and partisularly *th@ material stored in the upper atmospheres scntains an excass, =| The sr 90/gp89 ratios are quite constant for a given time sifice detonation, as shown in Table 8. However for mixed fallout from mors than one serias the Sr? /sr89 ratio can probably be used only as an approxifration of the relative amount of material from each series. The net effeot of fractionation appears to be minimal, As the Sr°9"90 measured in soil is in good acreement with the ty, based on measurements of total fallout in the area and contribution of Sr°’"’™, froted earlisr, pradicted activi= Ithe theoretical Of interest; is the comparison of 89/90 measured in bone w#th the ratio predicted in soil, The latter is based on fallout measurements, and takes the age of the fallout into consideration. As seen in Ficuge 7, the ratio in bone is higher than predicted bv a factor of about 2,