61 5. RESULTS Thirty-three surface sediment samples and 75 sections from nine sediment cores were measured for the y-emitting radionuclides and °°Co. 24) Am, 207,. 155 137 Cs Eu, Bi, All of the surface sediments and about one-half of the core sections were analyzed for 2385, and 23942405 in the course of the project. Over 150 plutonium analyses were made In addition, 22 uranium, 39 2105, and 26 226p4 concentrations were measured in selected sediment samples. Tne results of the 23854, 23942405, 241, s 20735, Seu, 137 66 and 60-4 measurements are shown in Appendix II (surface sediments) and Appendix III (sediment cores). 5.1 Radionuclide Distributions in Surface Sediments The concentrations of 23942405, 2385, + 24l an, 20754, 150, 1376, and 0c in surface sediments, in additon to being found in the appendix data tables, are displayed at their respective collection stations within the atoll by a series of areal distribution maps. To obtain the best estimate of the concentration of each radionuclide at each station for use in these maps, al] of the concentrations measured in lagoon surface sediments (including the 0-2 em sections of the cores) collected at the same sampling station were averaged. In crater-station samples, the measured concentrations were similarly averaged, with the following exceptions: Samples C-10 (s-34) (Tewa) and C-1) the severa] other samples from these crater stations, and were omitted from the average. The low concentrations measured in these samples may be partly due to the fact that these two sediments were collected away from the central wr eee er ere oe ee ee (s-16) (Zuni) contained radionuclides in much lower concentrations than did _ a. Note that in "“crater-stations,” only the prefix "C” is common to the samples from the same station. See Fig. 7 for the sample numbers which were common to the same stations.