of the muscie, and in carnivores about two to three times those of the muscle. Differences between these three tissues seemed to be greatest at Rigili, Engebi, and Aaraanbiru in postshot fish. Aside from the exceptions at Japtan and Igurin mentioned above, the liver was usually much more radioactive than skin, bone, and muscle. The averagefor all fish livers combined was about twice that of skin and bone at preshot stations, increasing to about nine times ir the postshot fish. The increase in activity in postsrot over preshot carnivores was less than that of omnivores. Of the preshot fish samples omnivores from Engebi had the highest count in liver tissue. After the shot Bogallua omnivores had the most radioactive liver tissue. The gut averaged about twice as high as the liver at all preshot stations, increasing to four times in postshot fish; the greatest increase was found in omnivores at Engebi. Postshot carnivores at Bogallua had three times as much activity in the gut as carnivores at Engebi. Comparatively high counts were found in the gut of preshot fish at Rurit and Engebi and, to some extent, at Bogombogo and Aomon, Fish with the lowest activity in the gut were collected at Japtan. - Distribution of radioactive materials throughout the tissues from gut to muscle was fairly uniform in preshot and postshot fish from Japtan and Igurin. For example, by comparing the radioactivity in the gut with that of muscle of all fish, the preshot activity in the gut was about 2.5 and 1.8 times that of muscle at Japtan and Igurin, respectively (Fig. 4.2). At other islands the ratios between gut and muscle were markedly greater: about 10.3 times at Rigili, 35 times at Bogombogo, 100 times at Engebi, 68 times at Aomon, and 352 times at Runit. Postshot ratios were as follows: Japtan, about 1.5 times; Igurin, 42; Rigili, over 3000; Bogallua, 107; Engebi, 310; Aaraanbiru, 1000; and Runit, 940. Ratios between tissues thus seem proportionately less with distance from shot islands, with the exception of Rigili, and were least to the south and southeast within the Atoll. The average increase in all tissues from preshotto postshot activity was greatest by far at Bogallua (Fig. 4.2 and Table 4.10). Although Engebi and Bogallua were about equidistant from the target center, the amount of radioactivity in fish tissues at Bogallua showed an increase of 4 to 18 times that of the fish tissues at Engebi. The data indicate that, of the radioactive materials taken into the gut at Engebi or Bogallua, a greater proportion reached the muscle, skin, bone, and liver of fish at Bogallua than at Engebi. 4.6 LAND PLANTS The plants collected before and after the shot included 15 species of flowering plants, 4 species of fungi, and 1 species of lichen. Someof the plants were collected at only a few of the stations. A check list of land plants collected is given in Appendix E. In general, col- lections were made in the areas where rat traps were set (Sec. 4.7.1), but a few were made along the beach or wherever it was possible to obtain certain of the species. Some plants were pressed directly in the field for future use in autoradiography; others were preserved for identification. Radiological assay of the plants followed the same procedure used for the other organisms. Counts were made on leaves, atems, roots, flowers, fruits, and fungi. 4.6.1 Analysis by Area Table 4.14 is a summary of the activity found in all the plants collected at each station before and after Mike shot. Counts of all plant parts are included in the averages. The greatest amount of activity was found at Engebi Island both before and after the Mike test. Since landings were not made at either Bogallua or Bogombogoafter the shot, there were no collections at these islands. In general, the activity levels of the land plants were lower than those of the algae collected at the sameisland, but the trend is similar. Plants from those islands closest to and west of the shot island contained the highest activity. Most of the plants at Engebi and Rojoa, as well as someat Rigili, were either burn<d or physically damaged after 47 _UNCLASSIFIED 7 aw dt