15 Measurable amounts of radioactive materials were found in the water at each station sampled. In general, ern part of the area had the lowest values. the northwest- The highest read- ings were from station 9D near the northwestern edge of Bikini Atoll. The surface samples had a higher average value for total radioactivity, 10,000 d/m/l, than samples from other depths. This value is the average of the sums of the radioactivity of the residue on the filter paper and that in the filterable portion. Water samples obtained from the 100-meter depth had the lowest average radioactive content, 3,900 d//.. The distribution of the radiation in the water at the depths sampled is illustrated in Figures 12 to 16. The highest radiation levels for each depth sampled were at station 9D, immediately north of Bikini Atoll. A second area of concentration was found in a limited region north and west of Eniwetok Atoll. In only the surface samples did the particulate matter retained on the filter paper have a greater radioactive content than the filterable fraction (Table 3). In the surface samples sixty per cent of the activity was recovered in the carbonate precipitate. In samples obtained from the 25, 50, 75 and 100- meter depths, most of the radiation passed through the filter paper, indicating that it was in solution. While radioactive materials were found at all sampling stations the decline of the amounts found around the edge of the area under study suggests that the regions of greatest contamination were included in the survey. rtvdo