163 Acute and chronic intakes of fallout radionuclides @ S. L. SIMoNn ET AL. Table 1. (Continued) Population group Nectar Zuni Flathead Tewa Cactus Fir Koa Maple Redwood Cedar Ailinginae* Ailinglaplap — 168 — — 71 — — — — — 179 — — — — — — — — Bikini community” 182 — — — 183 — 101 — Enewetak community* 112 31 59 Ailuk Arno Aur Ebon Jaluit — — — 98 — — — 91 84 182 — — — 126 126 — 84 — 126 154 Majuro Maloelap Meyjit Island — — — Mili 70 182 Kwajalein Lae Lib Island Likiep — 76 — — — — — — — — 25 84 161 158 189 60 63 — — — — — — 174 197 192 — — — — 104 91 98 — — — 98 67 104° — — — — — — 188 185 76 — 101 — — — — — — 101 101 101 — — — 160 157 84 — — — 101 101 102 — — 17 102 17 — — — — 104° — — 76 — — — — — — — — — — 154 126 140 — — 76 — — — — — 98 — Utrik community Wotho Wotje 112 70 92 energy expenditure, and body surface area (ICRP 2002). For the ages younger than adult, we found that the age dependence of body surface area to be most similar to the age dependenceof the reported bioassay data. Ourinterpretation of body surface area as a surrogate index for scaling adult intakes to younger age groups is related to the concept that particulate contamination of the face and hands (whose area can be considered to be a constant fraction of the body surface at each age) was a major contributor to internal contamination. This would be particularly true for children, for whom hand to mouth contact is frequent. The age-dependent acute intakes, relative to adults, selected in this study are presented in Table 2. For the youngest age group (<1 y), we assumedthat there are two sources of intake: the consumption of mother’s breast milk and the ingestion of fallout particles. The intake of a given radionuclide via mother’s breast milk is the product of the mother’s radionuclide intake, the fraction of the activity of each nuclide ingested by the motherthatis transferred to breast milk (F,,,,), and the consumption rate of breast milk by the infant. We discuss the derivation of these — — — — — — 92 — — — — — — 42 — — — — 60 101 — 101 101 101 Rongelap Island community* Rongerik® 84 91 — — — — — — — 119 165 — — — — — , — — 63 182 154 — Ujae — 101 — Namorik Namu Rongelap control group* 126 — — — — — 176 — — — — 189 — — — 101 101 105 — — — — — 76 84 70 — — — — — — — 101 — 101 — — — 101 — — 17 — factors in a later section. In addition to the intake of radionuclides via breast milk, we assumed infants (O-1 y of age) had direct ingestion of fallout equal to 10% of the adult intake (Table 2), since the body surface area of the infant is about 10% of that of the adult (CRP 2002). Chronic intakes Chronic intakes of radionuclides that persisted in the environment for years after fallout deposition were also assessed. The environmental pathways resulting in chronic intake are substantially different from those of the acute Table 2. Assumed age dependence of acute radionuclide intake relative to adult intake. Age category (y) Acute intake relative to adult <1 1 to <3 3 to <8 8 to <13 13 to <18 =18 0.1 + breastfeeding 0.3 0.4 0.6 0.9 1