171 Acute and chronic intakes of fallout radionuclides @ S. L. SIMoNn ET AL. Table 7. Parameters used to estimate '*'I and '°’Cs intake among adults based on urine bioassay (Harris et al. 2010) following the Bravo test and '*’Cs intake per unit ‘Cs deposition. Group sampled (ID) Date of sampling Assumed time of intake (H+h) Sampling to counting (d) cps per 500 mL Average 24-h urine production (mL d7') for adults Number of persons sampled for urine in pooled samples Estimated excretion fraction on day of sampling (see text) Average intake BY (adult, kKBq) 87Cs deposition from Bravo (kBq m~) 87Cs intake (kBq) Cs intake per unit Cs deposited (kBq per kBg m™’) Uncertainty of '°’Cs deposition (GSD) Weighted average '*’Cs intake per unit '°’Cs deposited* Marshallese adults on Rongelap Island (LA316R) 3/16/1954 Marshallese adults on Rongelap Island (LA317R) 3/17/1954 8.4 Marshallese adults on Sifo, Ailinginae (LA319S) 3/19/1954 8.4 American military weather observers on Rongerik (LA319A) 3/19/1954 5.6 11.2 14 70 427 13 76 448 11 33 385 11 20 1,072 35 31 15 9 1.73 x 10 1.63 x 10“ 1.42 x 107" 1.85 x 10~* 3,310 3,680 1,320 1,710 100 100 32 67 2.9 0.029 3.2 0.032 1.5 0.031 (Rongelap and Ailinginae) 1.2 0.036 1.4 0.021 1.8 2.0 0.021 (Rongerik) * Logarithms of '*’Cs intake per unit '°’Cs deposition inversely weighted by variance of '*’Cs deposition (see text). '’Cs per unit of '°’Cs deposited. We calculated the intake of '°’Cs per unit deposition of '’Cs separately for the and LA317R, Table 7) and Ailinginae (LA319S) and 0.031 Bq per Bq m* (Table 7). This indicates that the fallout ingested by adults was approximately equal to the material deposited on 310 cm’. Our evaluation of the likely exposure conditions agrees with those of Lessard et al. (1985) and suggests that particulate contamination of Bravo '°’Cs deposited at the two atolls. For the three of foods, utensils, hands and face, and to a lesser degree, drinking water, led to the internal contamination of pooled samples of adult urine collected from populations exposed to Bravo fallout on Rongelap (groups LA316R weighted each by the relative precision of our estimates urine samplings (LA316R, LA317R, LA319S), our esti- mates of '*’Cs intake per unit deposition of '*’Cs were 0.029, 0.032, and 0.036 Bq per Bq m~ while the estimated uncertainties of the '*’Cs deposition at Rongelap and Ailinginae, expressed as geometric standard deviations (GSDs), were 1.5 and 1.8, respectively. Our best estimate of the '*’Cs intake per unit '°’Cs deposition was derived from a weighted average" in consideration of the uncertainties of the '°’Cs deposition, and was found to be * The logarithms of the point estimates of °’Cs intake per unit 87Cs deposition had associated multiplicative uncertainties (similar in form to geometric standard deviations). These estimates were used in a conventional inverse variance weighting method (see Bevington 1969) as follows: h= S\(x/0?)/ > (/e2), adults. As expected, our average estimate of intake per unit deposition for American military weather observers stationed on Rongerik was less than the average for the Marshallese since their lifestyle was less dependent on outdoor food preparation. Our estimate of intake for the military weather observers stationed on Rongerik was 0.021 Bq per Bq m°(also based onbioassay) or about two-thirds of the intake per unit deposition experienced by the Marshallese on Rongelap. We interpret the estimated smaller intake per unit deposition of the Americans to be consistent with our belief that the military personnel took, at least, some precautions against ingestion of fallout particles. According to the records of Sharp and Chapman (1957), some of the military personnel worked indoors during the day though others continued to work outdoors. Hence, the