著者

谷田沢 道彦 石原 隆

出版者

公益社団法人 日本農芸化学会

雑誌

日本農芸化学会誌 (ISSN:00021407)

巻号頁・発行日

vol.29, no.3, pp.229-234, 1955

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In the preceeding papers⁽³⁾the authors reported the radioactive contamination of plants⁽³⁾ in Japan covered with rain-out from H-bomb detonated in Spring 1954, at Bikini-atoll. In this paper; absorption of the fission products by sweet-clover and rice plants are released.<br> <b>I. Investigation on the radioactiv contamination of sweet-clover</b>.: Sample plants were taken from grass-land of Shiga Agr. College at three different period of time. In the field, sweet-clovers were cut down at about three weeks interval, and every time new leaves sprouted before long. Since early of June, radioactive density of rain had greatly decreased.<br> Plants ash was analysed in routine procedure of inorgenic separation⁽⁶⁾. Ratio of radioactivity of each analytical group was shown in Table. 1. By examining the table, it may be concluded that radioactive alkaline earths especially Sr₈₉ and S_??_⁹⁰ were selectively accumulated in plants from the fact that the increasing ratio of alkaine earths highly exceeded what was brouhht from different half-life time of each radioactive elements.<br> <b>II. Selective absorption of Bikini-ash by rice plants</b>.: A part of long-line (rope) on board No. 5 Fukuryu-Maru was ashed and then dissolved in nitric acid. Excess of acid were neutralized with ammonia to pH 5.2, and diluted with 1 distilled water. Resulted solution was evaluated as about 4m&mu;c/m<i>l</i> in its radioactivity.<br> Nbn-contaminated rice plants were cultivated in this radioactive solution for 20 days in greenhouse, then the absorption by plant of Bikini-ash was examined radiochemically. Group separations of radioactive elements in plant ashes and remaining culture solution were made chromatographically in the use of cation exchanger Amberlite IR-120. Elution curves were shown in Fig. 1 to 3. Total radioactivity and ratio of each separation group was shown in Table 2. From these figures and table, it becomes clear that rice plants accumulated larger parts of fission products in their roots, and selectively absorbed and translocated radioctive alkaline earths in their shoots even if the absorption ratio of Bikini fission products was comparatively small.