1S . ’ . ‘ . . ” at oa a eo wooo .° vate . veer . f an . . oa so oe . « . affected the southern more than the northern part of fongelap Atoll. Samples 6076-77 of plankton collected July1956 from the Rongelap_ ro Island vicinity of Rongelap Lagoon were more radioactive when first counted one month after collecting than the corresponding sample (6079) from the lagoon near Kabelle Island.- ‘Gre ofthe‘Rongelap “ At Island samples (6077) was about 24 uo to 9 times more|‘Padioactie than oe the other two samples and decayed most rapidiy of tnose’stiudied. wens Within S weeks it was less than half (.44) as aotie:Gewhen first ena e. counted, while the other two samples decayed only.0.0.5 *%¢ of ‘their , re original values. When recounted as much é as, a year.‘stilt later, toe this sariple that had originally been the highest of‘the ‘three was af least radioactive of all, thus verifying its sgrller®Fapiadecay. gE Furthermore, the other Rongelap Island sample, algo, Aga ‘decayed’ more than had either of the Kabelle Island samples. an Decay of March 1958 samples was negligible during thetwo months from September to November 1958, while August 1958 samples decayed during the month of November 1958 fat rly rapidly, with,a“Waitelife . ay 3 of atout 100 days, tnus supporting the assumption that theAnereased eh * levels were attributable to the Hardtack series of ‘Metonations. iB © The rate of decay of the samples collected in 3954,‘was less steep than the rate of decline or radioactivity in Ronge1ap Lagoon plankton. [In Figure 3 the decay slopes of curves,rto 3range, from -1.6 to a maximum of -2. 4, even in the steep portion fron 660 to 1740 days, + while in Figure 2, the decline slope shown by the’‘aotted line