-2(mullet), suggesting that selection in favor of the non-fission isotopes was occurring in these animals, Kawabata (1954) reported the presence of the non-fission product ano? in several organs and tissues of the albacore and big-eyed tuna, thus confirming the earlier postulate of Okano (personal communication to Kawabata), based on that and might be present. 1955; Yamada 1955; Mori and Saiki Yamatera spectra, Subsequently this isotope was identified in several species of fish (Rinehart UWPL-43 7 et al., 1955; et al., 1955, 1956; Saeki, Okano, and Mort 1956; Yoshii 1956; Nagasawa et al., 1956) and in plankton (Seymour et al., 1956; etal., 1957). In 1956 two additional non-fission product isotopes were reported in biological samples: 60° by Weiss and Shipman (196 ) and Fe?? by Amano et al., (1956). Amano and his co-workers also postulated the presence of Fe? on the basis of decay and absorption characteristics of the iron fractions. Yoshii (1956) also suggested the presence of Fe? in fish samples and Kawabata (personal communication, paper in press) subsequently confirmed the presence of Fe? in contaminated fish, In 7Y spectra studies done by the present authors during the latter part of 1956 the presence of Zn 65 and °° in many organisms was established; also the presence of Co", C08, and Mn 54 in several samples was suggested. of the above isotopes were identified. were found, In the present study all In addition Fe? and Feo?

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