the external dose assessment, pandanus fruit and breadfruit. is based For living upon the unmodified conditions for the pattern III, for example, the total village island. terrestrial bone dose is 75*rem, of which The largest contribution to the whole-body and bone doses comes 74% is derived from the intake of bread- from the terrestrial food chain, the ex- fruit and pandanus. ternal dose pathway is the next highest however, that the large contribution tc contributor, the bone dose via these fruits occurs only and the marine food chain It is important to note, and inhalation pathway contribute the when they are grown on northern islands, least.” The relative contributions of each Pandanus and breadfruit grown on the less diet component to the terrestrial pathway contaminated southern islands lead to dose is shown in Tables 242 and 243, much lower dose commitments. Table 245 shows the 30-yr integral In general, living on JANET, visiting northern islands, and maintaining dose for the six living patterns for the agriculture on northern islands (living modified soil condition, i.e., where the patterns III, V, and VI) lead to signifi- village area has 5 cm of gravel and the cantly higher doses than if the village and village island is plowed. agriculture are located on islands in the shows the 5-, 10-, 30-, and 70-yr dose southern half of the Atoll (living pattern estimates for the same conditions. I). Doses for these same patterns have heen calenlated for & 10) Table 246 Table 247 shows the additional effect and 70 vr and on the 30-yr integral dose of limiting growth of pandanus, breadfruit, coconut, are shown in Table 244, and tacca to the southern islands, while The most significant contribution via the terrestrial food chain is the dose to Table 248 shows the effect of limiting all bone resulting from 905» uptake via terrestrial foods to the southern islands. The effect of the combination of these preventive measures reduces the dose for “As indicated earlier, these dose calculations assume that the Enewetak people will continue their current practice of living pattern III from 11 rem to 1.9 rem for whole body and from 80 to 4.7 rem using catchment rain water for drinking and that the underground lens water sup- for bone. A comparison of the 30-yr integral dose ply will not be a part of their diet. An indication of doses that are to be expected from lens water may be obtained from for living patterns I and III relative to the average United States externa] background four water samples taken on JANET in July 1971. These samples, two each from each of two 2,5-m-deep holes about 100 m from the lagoon shore, gave aver- dose over 30 yr is shown in Table 249. Plutonium isotopes, because of their age concentrations of 130 pCi/liter for 90Sr, and 400 pCi/liter for 138%Ccs, 239py long half-lives, will still be present <0.03, and 17 pCi/liter) but, for our current purpose, we will assume an average at the Atoll have decayed away; therefore, concentrations were scattered (<0.03, 21, value of 20 pCi/liter. when the other major isotopes observed Tables 250 and 251 are included to show Using these concentrations, and the predicted doses from plutonium to assuming an average daily intake of 100 m1 of lens water, the resulting 30-yr doses would be 0.83 rem due to °9Sr, 0.019 rem due to !8?Csg, and 0.00082 rem due to 239pu, the three major receptor organs (lung, liver, and bone) via the three relevant exposure pathways. II-60