96 naturally occurring radionuclides was also used to help detail the origin and accumulation processes of sediment and transuranic radionuclides with depth in the sediment column, in selected samples. The results of these measurements are found in Table 15 (uranium), Table 16 (“" 226 Ra), and Appendix III (219p9), Station C-3 (Bravo Crater) Sediment Core. The distribution of 238, U, 226 Ra and 210 Po concentrations measured in the Station C-3 core are also shovm in Figure 22. All three radionuclides show increased concentrations in the 0-10 cm region of the core, compared to their concentration in lower sections. Although the distribution profiles of these three radionuclides are not as wel] detailed as the 24) Am or 155 Eu profiles measured, the increase in the 226p 2105, and uranium concentrations in the 0-10 cm layers is not apparently different from the well-defined increase in the 24) Am and 155 Eu concentrations which were observed in detail. Although the absolute uranium concentrations measured in the 0-2, 6-8, 30-32 and 50-52 em'sections of the core varied by a factor of 4, the 234 238), ratios in each section varied from 1.06 by less than 2% (< 1 S.D. propagated counting error). These observations indicate that either: (1) 238), and 234), contamination have been selectively added to sediments in the upper 8-10 cm of the core in activity concentrations similar to those present in (on) the coral in lower sections (whose radiological signatures differ in other respects), or (2) the pulverized materia) in the upper 8-10 cm of the core is old sediment (of about the same apparent age as the sediments in deeper sections) which naturally contains a higher uranium concentration, or (3) the 238) 2344 enrichment on the particles in the 8-10 cm section did not originate from bomb materials, but was artificially concentrated on the particles; first by a volatilization of the coral sediment in the fireball, and then condensation