17 . And, at the same time, the difference in 60 Co content between the goatfish from near the crater and those at Bikini I. is by a factor of about ten. . . 207... It appears that the physical redistribution of Bi is similar to that of 6000, but since the levels of 207535 are lower than those of 60K by a factor of about 20, we are at the ‘limits of detection, with the method used, from the crater. for samples distant The use of larger samples, chemical separation and more sensitive counting methods would make it possible to determine 6005 77s ratios in sediments, lagoon water and organisms in different parts of the lagoon. These ratios would indicate whether transported radionuclides were primarily in solution or on particles. If the ratios remained constant, that would be a strong indication of transport on particles. The results of analyses of selected samples for 20754 by gamma-ray spectrometry and by chemical separation are compared in Table t3. Bismuth-207 will be a useful tracer in the future because it has a long half-life, 30 years compared to 5.2 years for 6000. Plutonium-239, with a half-life in excess of 24,000 years, is another potentially useful tracer. The sample analyzed for plutonium were selected on the bases of collection location and content of gamma-emitting radionuclides, which indicate