pCi/g were found at any depth are Analysis of the sediment and core samples indicates the presence of 40K 60 90 101 102m 106 Co, Sr, Rh, Rh, Ru, enclosed in cross-hatched areas in Fig. 152. 1275) Thus it seems likely that soil bearing 13% og 1525) 1545) ate 20735, 235). 2385. 239, 2405, and high concentrations of plutonium — as opposed to pieces of plutonium — is largely 241 Am in some, but not necessarily all limited to a band roughly 350 m wide of the samples. across the island, uniformly distributed over the lagoon centered on the visible plutonium soil layer, Each nuclide is non- floor, with the highest levels generally Within this band, plutonium concentrations are greatest on found in the northwest part of the lagoon, the ocean side, less on the lagoon side, 2-3 km southeast of the islands ALICE and least in the island center — a finding through IRENE; the next highest levels are consistent with historical data which in- found in the area southwest of YVONNE; dicate that debris was bulldozed away and the lowest levels are found south of a from the shot point toward both shore- line extending across the lagoon from the lines after the event which produced these Southwest Passage to TOM. plutonium particles, for example, shows the distribution pat- Except for this band across the island, tern for 95. Figure 158, Similar figures have been there is no evidence which indicates that prepared for each of the predominant plutonium particles on or near the ground species found. surface in the larger area shown in Many of the radionuclides found in the Fig. 152 are also found at any significant marine sediment and core samples were depth below the surface. not detected in the water samples, in102mpy, 106R 1256) 1525) cluding and 235 Because of the discrete nature and random distribution of these particles, of course, the only way that their distribution could be further U. In only 15 samples from the northern part of the lagoon were 80 G6, established would be by analysis of very 1555), large volumes of soil, 13765 and 239, 24054 were positively 20755 and 241 am detected. identified in all samples. Radioactivity Levels in Enewetak Table 217 gives the mean surface water concentration of Lagoon 13765 and 239, 2405, in the four quadrants of the lagoon, in the ocean close to the Approximately 858 samples taken from the Enewetak lagoon environment were east side of the lagoon, analyzed by germanium gamma- areas in other parts of the world for spectroscopic (GeLi) and wet-chemistry comparative purposes. and for several In the plankton samples, the most techniques to determine the distribution of radioactive species in the lagoon, in- abundant isotopes observed were 90, cluding 345 sediment and bottom cores, (av 0.86 pCi/g, wet wt) and 207 Bi 82 seawater and seawater filters, 21 algae, (0.83 pCi/g), followed in decreasing order plankton, or coral, and 410 fish samples. Figure 157 shows the major sampling of abundance by ©°Co (0.68 pCi/g), 239, 2405, (9.39 pCi/g), 1° Eu (0.24 pCi/g), 744am (0.23 pCi/g), and !3’cs locations for this marine program. II-8