Fig. 5.4 Autoradiograph of Rongelap Pig Tibia, 42 hr Exposure. Animal Sacrifleed 58 Davs Post -eXposurc. 5.4 : - __ -" HUMAN STUDIES r 9.4.1 Excretion Gross beta activity measurements on the urine samples from Rongelap, Ailinginae, and Roneenk indicate siznificant contamination in the majority of samples. The variation in beta activity excreted 24 hours among individuals in any one group is quite large (Table 5.1). If the mean values of urine activity of the adults of the three groups six weeks after exposure are compared, it will be seen that the Rongelap group had the highest activity, 1208 d m 24 hours. The Ailinginae group had 553 d-m/24 hours, and the American group had 309 d.m 24 hours. A proup of the Japanese fishermen exposed to fallout from the same detonation had a urine activity comparable to that of the Rongelap adult group. Phe mean activity of the individuals under 15 years of age appears to be considerably lower than that of the adult group. An examination of the group collections analyzed by the viilrious Labormiuories involved showed fairly consistent levels of activity for the individual from day to day. The variation which occurs is not considered to be excessively lLirge for this type of study. The activity as function of time fell off rapidly due to the large component of months post-exposure the Rongelap urine was found to contain a barely detectable amount of beta activity, The results of radiochemical studies of urine indicate that Sr®™, Ba'*, and the rare earti group apparently constitute 77 per cent of the total beta activity at 46 days. Stran- tium-89 contributes 40 per cent of the total beta activity, Ba'“°— 11 per cent and the rare earth a . e t aepeee 92 Ssadiaihialieastehaa, atid) anitneeatieal Bal’? - Ea"? and uther shcrt lived radioisotopes. For example the Rongelap group had a mean activity of 1208 d.m 24 hours at 46 days and activity of 339 d,m/24 hours at 90 days. At six ' on nage gee preee eae : ‘ 1 . + " ops ye Mis | r