N-10 INHALATION DOSE The inhalation of dust can vary tremendously depending on activity. On Bikini Island ploughing an open field in the dry season would represent the high end of the spectrum: resting quietly at home or Sailing on the lagoon would be near the low end. Robison (Ref. UCRL 53805, p. 9) has revised his earlier excessive estimate based on 5 hours per day of ploughing. As an average now throughout the year, he takes 1 hour per day plus 23 hours under normal conditions, resulting in a daily intake at Bikini of .017 pci of plutonium-239,-240 and .0071 pCi/d of americium-241, totalling .024 pCi/d. To obtain the Rongelap dose, it was assumed that the distribution of particle sizes and of radionuclides was practically the same on Bikini and Rongelap Islands. Therefore, the inhalation dose on Rongelap would be to that on Bikini as the transuranic specific activity of Rongelap soil (0-5 cm) was to that of Bikini Island. The plutonium level on Rongelap was 29% of that on Bikini, and the americium level 12% (Robison 1982a, pp. 8, 12, 44, 56; 1982b, pp. 12, 14, 47, B10, B13). The daily transuranic exposures for adults on Rongelap were therefore: plutonium-239,-240, anericium-241, Total 29% of .017 pci = .005 pci/d 12% of .00071 pCi = .0009 pCi/d -006 pCci/d -The adult 30-year inhalation doses are estimated to be (Table 4.2 #1B): Tissue Plutonium-239 ,-240 (rem) Americium-241 (rem) Whole-body 023 004 Red marrow 035 -006 Bone surfaces -004 -0007 For the infant (to be on the safe side) we have assumed exposure to be the same as for an adult. Therefore, taking the total daily transuranic exposure as .006 pCi/d, we find the whole-body dose for the first year to be (Table 4.4 #1): 9000618 —