TRANS URANIC ELEMENTS AT BIKINI ATOLL 553 

 TABLE 3 (Continued) 



*Mean ± 2 standard deviations. 



A long core (56 cm) of entirely pulverized sediment was collected from the center of 

 the Bravo crater (station C-3). Three segments of this core (the 0- tal2-, 26- to 34-, and 

 48- to 56-cm regions) were cut into 2-cm sections for the radionuchde measurements. The 

 concentrations of radionuclides (Fig. 8 and Table 3) measured in the two lower regions of 

 the core were similar to the uniform concentrations measured in the Zuni crater core. In 

 the surface 12 cm, however, a well-defined layer of high-radionucUde concentrations was 

 centered at the 6- to 8-cm depth. Elevated concentrations of all radionuclides were 

 measured in this section, which contained the highest concentrations of ^^^Pu 

 (8.3 pCi/g), ^^^Bi (432 pCi/g), and ^^Co (306 pCi/g) measured in any Bikini sediments 

 except for the one higher ^^^Pu concentration (19.0 pCi/g) that was found in Zuni crater 

 (station C-12) sediments. The ordering sequence of radionuclide concentrations in 

 different regions in the core differed greatly. This ordering sequence can be compared 

 with that for surface sediments shown in Fig. 9. The sequence in the 0- to 2-cm section of 

 the core differed from that in lower sections and from that found in the three other 

 surface grab samples collected across the crater; these grab samples also differed from 

 each other. In the 2- to 12-cm region of the core, the order in the sections was Bi > Co > 



