5, Conclusions it was initially intended to measure the # anc y activities of radioactive nuclides after chemical separation of the elements. As the work progressed, it became evident chat modifications of usualy fj rocedures vere necessary to achive adejuate separations of the elements encountered in this anslysis. The procedures adapted enable recoveries of greater then 70% of the original samples to be attained. The redioactive decay pattern of the total rare earth fraction indicated the presence of essentially '44.6 - Mtpr , with sossibly traces of other rare earth clements. The seperation and determination of Ce and Pr is usually accomplished by the solvent extraction technique utilizing methyl— ig@butylketone. Although the determination of “zr - On in *Vasam Yugi l. % Nb was r—-ray not carried out in this analysis, the exsistence of these nuclides in planktons indicates the necessity of establishing methods for the chemical separations and determinations of the-> elements. An investigation concerning the analysis of these elements is currently being conducted in this laboratory. The exsistence of 65on and 7Y-ray puls hi 19 fishes Two Sp cau peak were detected natural **¢K¢1, °®go in plankton through 7 counting was first suggested by Dr. Tsuruga and these determinations were carried out during the process of this analysis. In the g of 9 Zr5 Nb we Although the level of radioactivity of tuna fish examined is rather low, the results suggest their intake of other sealife may contain much higher concentrations of radioactive substances. | % National In:

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