piggies, aeRee ‘ a Bobb. -cosg ac 8 pee Tap at et apier overs othe’ sn 1 : . . The sol] and- sand. samplesincludedthose fromthe islands — meme mare 7 : ‘proper, fromthe beach, and fromthe lagoon bottom. - The radio- activity of a sample taken from the top inchof soil on | Labaredj-Isiand March 26, 1954, wae 6.3 microourles per gran, which is equivalent te one curle per .325 pounds. of top soll. Phe activity ofthis sample ten months later, January 29, 1955, _was one thirtieth its original value, t.e., 1¢ had passed throughnearly five half~Lives. .The deeayrate fer this period 4s expressedby the formula, r= ¢ 7/51, with March 1, 1954, .as-the date of origin (Figure 12), Thisvate approximates the mixed.fission product decay rate and in general approximates the decay rate for many of the biological samples. For these ae ‘Péasons the decay faetor tor correcting counts back to the day of colleation wea paged on the decay«ourveof a‘similarsoft ‘sample, | “The decline in radioactivity of the soll samples ean ‘be i ae “Sbaervedfrom‘the figures in Appendix ‘TableXe ‘considerable’ oe “variation in.‘the activity of soul samples trom ‘the same‘area on TE the game day ¢an be expected ‘because of the nature of the fall- out:‘pattern and should be kept in ‘ind’wheninterpreting results. “ “1954, but less from guly 1954 to ‘Jamuary1955. then the sample pte ‘ofdecline is greater than the. decay rate ‘from‘aréh to saty’ “eounta fron all istands are ‘averaged,the ‘Felative¢decline an Boncommre es SOE Gh RETSTEoS EEOTRRegreer “If consideration 1s given to the Fabelle séupies only, ‘the rate ceeikonaa-tiedesuicean egeivetot totty ene: