Transuranics in Bikini Lagoon 731 data we explain iome specific raL cooperative pro- ygeochemical be1 elements at Bire collected in e RV Palumbo, ico Nuclear Cenwledge the help the RV Palumbo Lowman and W. cipating investirowth results study was a live 2dged in Novemf 28 m at station '. In the periods ruary-May 1954, July 1958, Bikini ies of nuclear deavents in the last ted along the in1 perimeter of the m the reef (1954: ; 1961) produced in Fig. 1. f Am, iby "Co, an from lacation B-3; m date, 8 November ; TTT rin % of value) ~TL£6 1.16410 2.6446 3.6724 2.7844 0.9645 0.39416 0.38416 5.0642 6.8343 7.4543 4.7845) 2.006 0.8929 0.60412 1.3848 2.3146 11.8242 12.4143 3.6245 1.1448 0,68+10 Fig. 2. Autoradiograph of a cut vertical section from the coral sample. Radioactive regions have been retouched for better contrast. The distributions of specific radionuclides in the lagoon are extremely heterogeneous (Noshkin et al. 1974). For example, the 1972 activity levels and isoactivity lines of “1Am in the surface 2.5 cm of sediment deposit (Fig. 1) show that the region around station B-3 was heavily contaminated with artificial radionuclides from the test series. Table 1 gives the levels of several radionuclides to a depth of 35 cm in a sediment core from station B-3. Levels of radioactivity are relatively high throughout the column. The coral from this location should reflect the changes in activity during its growth cycle in this contaminated region of the lagoon. The coral surface was washed and the specimen was dried at 110°C for 1 week. The sample was first cut in half vertically from the surface through the base. (Wealways cut from presumably low-radioactivity sections toward higher level sections to