SLIDE 21 Radioactivity intake estimated from excreta. The fraction of an initial 131; activity intake by ingestion that would be eliminated by an adult on a given One was a model by Johnson day post the intake was calculated by two methods. (Jo81) and the other was a model used by ICRP (ICRP79). Both models had feedback incorporated into the estimate of the fraction of initial intake. Both were solved using catengry compartment kinetics and both led to similar I by a reference man. Based on 0.48 kBa (1.32 x valyes for elimination of 10°“ #Ci) in adult urine intake was estimated for 18 I.the 17th day post intake, a 3,440 kBq (93% lang Ci) The intake of 3,440 kBq (93 s# Ci) Yas used as a normalization point. That is, once the relationship between I and other nuclides in fallout was determined by us, then the contr} bytion to thyroid dose from all radioiodines was estimated while keeping the I intake at 3,440 kBq (93 BCL). Whole-body retention functions were given by ICRP (ICRP72) for strontium and barium as follows: =5 -4 Rg(t) = 0.60082540 ,299(£40.20)-0+18(0, 555¢76+ 5x10” tag gu5en2eOx107 Mt, _ _ 4 _ “4 Rya(t) = 0.38e0°7 940.191 (t+0.007)70*237(0, 56407! 20910 “tay 436074 36x10 ty | where t is in days and R(t) is the absorbed fraction remaining on day t. The fecal to urine ratios for excretion of absorbed Sr and Ba wer 0.25 and 9.0, respectively (ICRP72) Correcting for45 days of decay, the 125 activity absorbed was estimated to be 2.3 x 10° Bq (0.62 pCi) and the Ba activity absorbed was 6.1 x 10° Bq (16.4 Aci). If fallout was directly ingested as a single intake of dust at 0.5 days post detonation, then the intake of 140 905, or L3ly should be in a ratio similar to one estimated by us by a different approach. The fraction of ingested iodine absorbed into blood was taken as 1.0, the fraction of ingested strontium absorbed into blood was taken as 0.2 and the fraction of ingested barium absorbed into blood was taken as 0.06 (ICRP68} 4 The tR5ake ratios we obtained from urine results for I relative to ~*Sr or Ba are 28 and 0.34, respectively. The hypothetical ratios are 8.5 and 1.2 based on unfractionated thermonuclear fission data. Thus the urine derived patio of activity is a factor of 3, kewer than the hypothetical ratio for Sr and a factor of 3 higher for ESTIMATE OF ACTIVITY INGESTED (RONGELAP) Nuclide Activity Iodine Activity® Bq Nuclide Activity Ingested ae a9 3.4x10°5 Ba 1.0x107 Sr 1.2X10 et 1.0 8.5 1.2 *Thermonuclear neutron fission and 5 hours post detonation. 26 Ba.