DNA 1240H-2 elliptical contaminated surface urea with the leading edge about 2.5 mt west of the shot point at H+ 2 hr. of 50 ft at early times. The contamination extended to depths According to Ref. &, the greatest amount of radioactivity in the water ot surface zero at H + 48 hr was found in samples taken below the thermocline, which was located at 100 meters. Doses due to the water recorded in the second hour after burst appear to be insignificant. Floating film pucks dropped into the down- wind array 120 min after Wahoo und 00 min after Umbrella "did not register any dose significantly above background; therefore the film-pack data indicate no contribution from radioactive material suspended in the water after those times." Reference 32 concludes that the passage of radioactive foam would represent a serious hazard to small boats between 5 to 15 min after burst, although waterborne radioactivity is of secondary importance aboard ships.” Investigation of the radioactive contamination of the water following Shot Wahoo 8 indicated that, at the end of 3.5 days, the boundaries of the radioactive water mass extended beyond the survey area, 50 mi to the west of Eniwetok Atoll, and to a depth of at least 300 meters. Analysis of water samples collected et 5.5 hr and 27 hr after detonation in- dicated activity present at all depths sampled (from the surface to 300 meters). The measured amounts of beta radioactivity in the water were the same at both times. At 48 hr after burst, at surface zero, the greatest amount of radioactivity was found in the samples tuken helow the thermocline. gperetion Wigwam: detonated On 14 May 1955, Shot Wigwam (about 32 KT) was at a depth of 2000 ft in very deep water. Reports of water- surface radioactivity from thie operation are contradictory, and it is impossible to determine which of the primary documents 2» is more reliable. Discussion of the depth-probe measurements®2 is also difficult to interpret. Reference 8&3 states that "Project 2.1 arranged that samplers be dropped and towed through the area, tut had no part in the sample recovery." Unfortunately, most of the samples were lost. *More recent data from the Sword Fish underwater shot, received too late for detailed inclusion in this report indicate that the early-time radioactive-pool hazard to larger ships can be of considerable significance during the first half hour after burst. BEST AVAILABLE COPY 17~96 - wee ee x wee ee ee ee ee te eee te oe