EFFECTIVE ARRIVAL TIME (HOURS) 0. 6 f -¢ 1 8 dy 9 Ty iO | tl | l2@ I I Tf 34 15 Tf 16 17 18 1920 PF 300 1000 000. =~ 2700 331900'7~ 2900 TOLL s pry 0 1020 —$59_ 40 104-158 75 60 80 FT] !00 120 UTIRIK RONGERI K ATOLL ,AILINGNAE ATOLL |; 40 FT ATOLL = 6072004 10055-80900 oT i40 yg i60 gt dG dt TAKA ye" ATOLL dg 180 200 220 240 260 280 300 320 340 DISTANCE FROM GROUND ZERO (MILES) Figure 1. Approximate gamma dose rates (roentgens per hour) at 3 feet above the ground, one day after the detonation. 2. From Glasstone (40). Residual Radiation To assess potential effects of low-level residual radiation persisting on Rongelap, Utirik, and Bikini, periodic monitoring of the inhabitants of these atolls as well as samples of native flora, fauna, were performed. E. soil, and marine life These studies are discussed in Section X and Appendix II. Data Evaluation Reevaluations of dose estimates are planned or under way using more so- phisticated technology and computer methods currently available, and it is possible dose estimates may be increased. In the meantime the dose calculations previously developed will continue to be used. co or Cc While quantitative variations in dose estimates have an obvious impact on dose/effect correlations, other considerations are equally important in these studies, especially regarding radiation induction of thyroid neoplasms (caveats regarding thyroid dose estimates are discussed in Section IX and Appendix II). Risk probabilities for development of neoplasms secondary to radiation have classically been derived for malignant tumors of specific organ systems.