The highest concentration of radioactivity was found in viscera with less in bone, skin and muscle, as shown in Fig. 1.
With water or EDTA-Na solution, some amount of radioactive material was washed off from the raw meat effectively (Table 1).
The radioactive materials contained in various organs of fishes were analyzed by the method shown in Fig. 2 (see also Table 2), and the results were summarized in Table 3 and 4.
The active substance in fishes was proved to be chiefly consisted of the radioisotopes belongs to III group, whereas those belongs to IV group (Sr, Ca, etc.) was relatively little. Members of III group were further separated in A (Al, Fe, etc.) and B (Zn, Co, Ni, etc.) subgroups, and the latter fraction contained also considerable amount of radioactive materials.
It is noticeable that Zn65 was detected in this III B group with the gamma-ray analysis.