Mike shot. Comparison of counts of damaged and healthy leaves from Rigili plants showed no al marked differences between the two, indicating that most of the activity was on the surface of the leaves. Table 4.14 RADIOACTIVITY OF LAND PLANTS BY STATIONS*® Preshot Bi Island Postshot Mean nn Max. Min. Japtan Igurin Rigili 0.014 0.28 0.58 14 22 17 0.074 «(3.7 8.6 Background Background Background Bogombogo 0.12 22 «1.6 Background Engebi Aomon and Rojoa_ Runit 0.83 0.28 24 «(3.4 3001.3 0.092 Background “Mean 0.24 16 100 1900 89 40 on Max. Min. 8 11 20 0.33 39 820 0.13 0.83 1.0 6 12 2 4000 370 60 280 4.9 20 * Measured in disintegrations per minute per gram (x 1000), wet sample. 4.6.2 Analysis by Species Because of the incompleteness of the collections and the great variation within species, it is not reasonable to attempt to determine whether significant differences in the amount of activity exist between species. From the data available it appears that bunch grass, Lepturus yvepens, had the highest activity of the plants collected at Rigili and Rojoa after the shot. On the other hand, Mycena, a fungus, was among the highest at Rigill, but lowest at Igurin. Because of inconsistencies of this nature, conclusions as to species differences are not justifiable. 4.6.3 Analysis by Organs No specific conclusions can be made regarding radioactivity in the organs of the land plants collected before and after Mike shot because of the inconsistencies encountered. At somecollecting areas the roots had the highest activity, at others the lowest. In general, the leaves were highest. An insufficient number of flower and fruit samples was assayed from the post-Mike series to warrant comparison. 4.6.4 Radiochemical Analyses Radiochemical analyses of post-Mike soils from Rigili, Rojoa, and Runit and of post-Mike I, plants from Engebi were made in order to determine the identity and relative amounts of fis- sion products present. By comparing the relative percentages of specific fission products in plants with those found in the soil and knowing the solubility of these fission products in water, it is possible to estimate which isotopes have entered the plant via the normal processes of mineral absorption. The results (Table 4.15) are tabulated as percentage of total recovered activity in the sample, although actual chemical yield was approximately 75 per cent of the total radioactivity in the samples. If the percentages of the radioisotopes in plant and soll samples are approximately the same, then it may be assumed that the radicactive material is adsorbed onto the surfaces of the plants. The radiochemical analyses and the analytical procedures are described in Sec. 4.8 of this report. The radiochemical content of the soils from the four islands is fairly uniform, with some exceptions noted in the Engebi soil. As in the soil samples 80 to 85 per cent of the radioactivity in the land rlants from Engebi was found in the highly insoluble fission products that are absorbed by the plants in minimal amounts under normal conditions. The remaining portion cf the radioactivity is found in the more 48 . UNGLASSi o