著者

白井 和雄

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.23, no.11, pp.723-728, 1958-03-25 (Released:2008-02-29)

参考文献数

6

被引用文献数

1

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In the previous papers on the radioelements in skipjacks, 1)2) the identification of Cd113m as a main contaminant and the presence of Zn65, Fe55 and a trace of Ba140-La140 were reported. The present paper deals with a contaminated big-eyed tuna, Parathunnus mebachi, caught at a station (12°17'N, 167°04'E) in the Pacific Ocean on Oct. 20, 1956. Data on the specimen are given in Table 1 and the radioactivity of tissues and organs is shown in Fig. 1. The ashes of liver, pyrolic caeca, kidney, red muscle and ordinary muscle were fractionated by the group separation method using carriers and the considerable amount of radioactivity was found in Group II (Table 2). Radioactive elements contained in Group II were proved to be mostly composed of Cd113m and Cd115m by the further fractionation (Fig. 2). The existence of these nuclides was confirmed by the half lives of Cd fractions (57-71 days when estimated directly and 43-44 days when traversed with 263.9mg/cm2 Al absorber), energy of β-ray (1.6 Mev) calculated from absorption curves (Fig. 3) and energy of γ-ray (1.1 Mev). Group IIIB and IV obtained from the liver, pyrolic caeca and kidney were supposed to be chiefly consisting of Zn65 and Sr90-Y90 respectively, judging from the decay and energy of β-ray, measured on the unrefined fractions (Fig. 6, 7). Member of Group IIIA were not thoroughly examined in spite of higher activity due to the disturbance of phosphate. Further confirmation of these nuclides will be dealed in the following papers.

著者

白井 和雄 佐伯 誠道 大野 駿

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.22, no.10, pp.651-653, 1957-02-25 (Released:2008-02-29)

参考文献数

2

被引用文献数

1

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Succeeding to the previous papers, the present paper deals with the presence of Cd113m. Group II, separated directly from the raw ashes of the liver or the pyloric caeca of skipjacks, Katsuwonus pelamis, or from the radio active fration, “6-L-F2”, obtained by ion-exchange resin, was fractionated further into each member (Fig. 1). The considerable activity was found in Cd-fraction in both cases (Table 1). The Cd-fraction showed no decay in 50 days and no γ-ray emission. The maximum energy was found to be 0. 6 MeV., when calculated from the absorption curve (Fig. 2). From these results, the nuclide in question was identified as Cd113m. The weak activity was also found in Sn-fraction in the above fractionation, but the nuclide has not yet been identified.