CHAPTER 4 CONCLUSIONS AND RECOMMENDATIONS In order to completely document the hazardous fallout activity resulting from the fission products and wranium neutron capture products on Operation CASTLE, one would have had to anticipate the wide- spread contamination that was produced. The scope of this project was limited to documentation (primrily on land and secondarily on water) at the shot atolls. Documentation on water, as it was done by this project, was not practical and was discontinued after the first shot. Fallout stations were set up in varying arrangements for Shots 1, ys 3> 4, and 6. When significant fallout occurred at an island after any of these shots, it apparently began to arrive there within six minutes after the detonation. The maximum activity per sampling time interval resulting from Shot 1 and other shots having yields of the same order of magnitude arrived at all sampling stations during the first hour after the detonation. Extrapolation of the beta activity has indicated rates as high as 1.3x1014 dpn/ft*, 1 to 6 min after detonation. The major part of the activity had arrived at a given station within 3 to 6 hours after the detonation, with small amounts continu- ing to arrive up to at least 12 hours after the detonation. Gamma dose rates due to each shot at the shot atoll 1 hour after each shot were estimated from data collected by this project and Rad Safe to be as follows: Shot 1s 1600 to 2900 r/hr along the northern islands, 160 to 630 r/hr on the eastern islands and 15 to 43 r/br along the southwest side of the atoll. Shot 2: 1100 to 4700 r/hr on the northwest islands close to ground zero and 2.4 to 14 r/fnr on the rest of the atoll. Shot 3: 410 r/hr at Uncle, just west of ground zero, 10 to 125 r/hr on the north and northeast islands, and 0.8 to 4.5 r/hr elsewhere. Shot 4: 160 to 440 r/hr on the north and northeast islands, and 0.1 r/for elsewhere. Shot 6: (At Eniwetok) Over 1000 r/hr in the immediate vicinity of ground zero, dropping to 17 to 32 r/hr on the islands westward and 1 to 6 r/hr eastward from ground zero. Within the atoll, there was no apvarent trend of radioactive particle size distribution with distance, direction, or time. 100 The