94 appear. Similar to the radionuclide distributions found in the B-2 sediment core, increased concentrations were measured in the lowest section of this core. As in both other cores from this region of. the lagoon, the 23942405, ratios measured with deptn in the core showed only a sliyghtincrease with depth. In the 8-16 cm region of the core, the ordering sequence of radionuclide concentrations changed from those found in surface sediments (Fig. 19} to the order Pu > Eu > Am > Co > Bi > Cs. This sequence is the same as that observed below the 6 cm section at Station B-2 and in surface sediments in the far western region of the atoll. 5.3-3 Central and Eastern Lagoon Sediment Cores The four sediment cores collected from the central and eastern regions of the atoll (stations B-27, B-16, B-15, B-30) were similar in three respects. First, there was no significant net increase or decrease in the concentration of radionuclides measured betyvieen the upper and lower sec- tions in any of these four cores. 2394240 24) am, T55, Pu, V3? 66, 207 Second, the distribution profiles of Bi and 696, concentrations are roughly similar with depth in the individual cores. Third, the 2394240 pu/?*8pu ratios measured in all but the Tower section of the cores from Station B-27 were Similar to the ratio in the surface sediment section. Because of the very short (6 cm) length of the station B-16 and B-30 cores, no further interpretation of the observed radionuclide profiles is warranted. ordering of Except for the 24) Am in one section, and 239+240 Pu in the 10-12 cm section immedi- ately below, the ordering sequence of radionuclide concentrations in the 16 cm core from Station B-15 is the same as in surface sediments (Fig. 19). In the 10-cm core collected from Station R-27, the sequence of 60¢9, 2073; and 13766 concentrations measured did not change with depth from that shown in Fig. 19. However, in the 4-8 cm region, 241 a was higher in concentration