summing. This gave 8949 rads for the total population original 550. including the The total dose received by the original 550, assuming that all live for the 30 years, is P’=? (1 - e-at) = 11,902 rads For those born after the return, the population would be the difference between the total population in 30 years, the number of deaths and the Thus, the per capita dose for this group original 550 people or 1134. is 8949/1134 = 7.9 rads. 11,902/550 = 22 rads. For the &riginal 550, the per capita dose is The ratio of these two to give an estimate of the fraction of the full 30 year dose received by the children is 0.36. The assumption of no deaths in the original 550 returning was made for simplicity and the lack of good death rate data. We also compared the age characteristics IV-3 and the U.S. population in 1970. attached curve. of the Marshallese This comparison from Table is given in the The slopes are similar above age 35 but the magnitudes are distorted by the high birth rate in the Marshall Islands. However, in terms of the relative risk the similar slopes suggest that if the natural cancer rates in the two populations are similar, the relative risk for people above 35 in both populations would be similar because most of the cancer occurs at ages from about 40 and above. However, the magnitude of the relative risk in the U.S. used for the Marshallese will be high by a factor of somewhere around 2-3 because of the distortion caused by the very high proportion of young people who have a relatively low natural cancer incidence. Using the preceding calculations for a population of 550, calculations were made for other population s- zes. For a population of 550 preceding): Deaths in 30 years = 164s Births in 30 years = 1277= 160 1300 For a population of 140 (the number that returned to Bikini): from