76 northern and eastern sectors of the atoll, respectively. In addition, in groups of stations (within the dotted lines in Fig. 18) the relative ordering of 6069, 1370, and 207 Bi changed, delineating still smaller areas. The sequetces found may thus serve as discrimirants for groups of stations where the ordering sequence of radionuclides concentrations are the same. additional discriminant, the ratios of As an 2394240, 2385), found in sur face sedi- ments at each station are added to the figure, since these ratios may also retain the signature of debris from individual devices. Comparison of these two "discriminant functions" show that although individual detonations may have disseminated unique proportions of radionuclides, mixing and/or fractionation of the radionuclides and debris from the several tests have left few conclusive signatures of individual sources in the laaoon sediments. The relatively high abundance of 185 Eu in north central lagoon sediments may j]ltustrate the area over which debris ejected from the Station B-18 and C-8 test areas has had major influence on the concentrations present in surface sediments. It may also be of significance to note the possible correlation between the distributions of high to the distribution of high 2394240, 2394240 Pu/ 238 Pu ratios south of Tewa Crater, pyri, 1 137%e5/88co and ow 23942405) W95e 4 ratios which are common both this area and the test areas around Station B-18 and Tewa Crater. 5.1-8 Uranium, Radium-226 and Polonium-210 The naturally occurrina isotopes 210 Po are members of the 238 U decay series (Fig. 19). 238 U and 234,, U, 226 Ra and The structures of orga- nisms which comprise the sediments of coralline atolls accumulate these radionuclides from sea water. In addition, deposition of 210 Pb and 210 Po in the Sediments results from aeolian and pluvial transport process. Because the activity ratio 2307, 234), in recent coral is less than 0.005 (Thurber et al.,