Radioactivity of Marine Organisms photopeak of a more abundant nuclide bidden by t he f approximately the same energy. with gamma rayS 0 have Nuclides If ype the latter category that might in the samples analyzed inciuded co- cobalt-60 and been expecteeariun-144 as well as emit gamma rays bas ginc-69. when two nuclides that of De Ne Pe Sady oftenRRR aR i a samtely the same energy are present in aero iten one nuclide can be identified by scan- ping the sa mma has been detected only in spiny lobster “liver.' Additional information on radionuclides to be ex- pected in marine organisms from the western Pacific can be found in the report of the Hansford Labora- tories on the radionuclide analyses of samples col- lected after the 1956 Redwing test series. ACKNOWLEDGMENTS spectrum for other photopeaks from the same nuclide or from assocated nuclides, without resorting to radiochemical methods. The nuclides listed in Table 1 were identified solely by scanning the gamma spectrum except for silver-110m, as mentioned above. Further analysis of the samples from Guan, Palau. and the Gulf of Siam for specific radionu- clides was not attempted because of the extensive work done by the Hanford Laboratories on radionuclide composition of similar samples collected af- ter the Redwing test series in 1956 (Thomas et al., 1958). To the extent that the 1956-1957 samples could be compared with the 1958-1959 samples there were no gross differences in resuits between the two groups of data. SUMMARY Following the Hardtack weapons test series at Bikini and Eniwetok in 1958, samples of fish, crabs, lobsters, snails, clams, algae, and plankton were collected at Guam, Palau, and in the Gulf of Siam by the George Vanderbilt Foundation for radiologi- cal analyses at the Laboratory of Radiation Bio- logy. The collecting areas were 1,200. 1,950, and 4,250 miles, respectively, west of the test site. The gross beta activity was determined for all samn- ples and the gamma-emitting nuclides were identified in selected samples. The rate of westward transport of local fallout from the Hardtack series by the North Equatorial Current was estimated at eight miles per day between the test site and Guam and Palau. The criterion for the arrival of the fallout at the collecting area was a Significant increase in the gross beta count of certain biological samples. The levels of radioactivity were considerably different for samples from the three collecting areas: the counts of samples from Guar were notably higher than those from Palau. which in turn were very much higher than those from the Gulf of Siam, whicb were essentially at background level for all collections Page 155 The western Pacific samples were collected by the George Vanderbilt Foundation, Stanford University, and sent to the Laboratory of Radiation Biology, University of Washington, analyses. . for radiological The program was supported by the U. 8. Atomic Energy Commission under contract number AT(04)3102 with Stanford University and contract number AT (45-1)540 with the University of Washington. REFERENCES Bonham, K. 1959. Further contributions on gross beta radicactivity of biological and related samples at the Eniwetok Proving Ground, 1952-1958. Univ. of Washington, U. 8S. AEC report UWFL-63. 41 pp. Dunham, C.L. 1959. Statement, Hearings before the Special Subcommittee on Radiation, Joint Committee on Atomic Energy, Congress of the U. S., May 5-8, 1959. Fallout from Nuclear Weapons Tests, U. 8. Government Printing Office, Washington. pp. 10- 154. Harley, J.H. (ed.). 1956. Operation TROLL. JHeaith and Safety Laboratory, New York, U. §. AEC report N¥O-4656. 34 pp. Heath, R.L. 1957, Scintillation spectrometry gammaray spectrum catalogue, Idaho Operations Office, Idaho Falls, 239 pp. Idaho, U. 3. AEC report IDO-16408, Libby, W.F. 1959. Ways of reducing world-wide or offSite fallout from testing at a given level. [In Summary-Analysis of Hearings, Fallout from Nuclear Weapons Tests. App. B. Special Subcommittee on Radiation, Joint Committee on Atomic Energy, Congress of the U. S., May 5-8. U. S. Government Printing Office, Washington. p. 42. Lowman, F.G. 1960. Marine biological investigations at the Eniwetok Test Site. In Vol. II. Disposal of Radioactive Wasteg, Intern. Atomic Energy Agency, Vienna. pp. 105~138. The gross beta counts of fish muscle from all areas from all collections were constant and less than seven micromicrocuries per gram of wet weight. The samples with the highest gross beta counts were Miyake, ¥., Y. Sugiura, and K. Kameda. 1955. On the distribution of radioactivity in the sea around Bikini Atoll in June 1954. Papers in Meteorology and Geophysics (Tokyo) 5(3-4): 253-262. of 204 and 356 micromicrocuries per gram, respec~ tively. Gross beta counts of some Guam and Palau Seckel, H., and K.D. Waldron. 1960, the Hawaiian skipjack fishery. clam kidney and spider snail liver, with maximums Samples prior to the arrival of the Hardtack fallout indicate the presence of radionuclides from prior test series. Gamma~emitting nuclides other than naturally occurring potassium-40 included, in order of abundance, cobalt-57, cobait-60, manganese -54, cerium-144, zinc-65, and silver-110m. The greatest value was 2,300 micromicrocurtes per gram Oi wet weight for clam kidney (Tridacna). The oclope ec? of silver-110m in the liver of the spiny obster was of special interest because it ig a previously unreported fallout nuclide and so far 58(3): 11. Oceanography and Pacific Fisherman Seymour, A.H., E.E. Held, F,G, Lowman, J.R. Donaldson, and D.J. South. 1957. Survey of radioactivity in the sea and in pelagic marine life west of the Marshall Islands, September 1-20, 1956. Univ. of Washington, U. S. AEC report UWFL-47. 57 pp. Thomas, C.W., D.L. Reid, and L.F. Lust. 1958, Radiochemical analysis of marine biological samples following the "Redwing" shot series - 1956. Hanford Atomic Products Operation, General Electric Co., U. S. AEC report HW-58674. 81 pp. DOE ARCHIVES

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