cabo . oe ee a intake of 13ly using 140g4 and 89%sr estimates of injected activities. The frac tions ingested and absorbed into body fluids were taken to be 1.0 for iodine, 0.2 for strontium and 0.06 for barium (ICRP68). We assumed instantaneous transfer from ingestion with meals up to the point of injection_into systemic body fluids. The corresponding estimated intakes were 1.2 x 109 Bq (3.1 uci) for I¢€ iodine, barium, and strontium 89sr and 1.0 x 10? Bq (270 uci) for 140n,. were taken as dust, then we estimate 1311 intake as 2.4 x 106 Bq (64.1 wCi) or 1.8 x 10’ Bq (490 uCi) based on strontium or barium intakes, respectively. i. Absorption ThroughSkin. According to Glasstone (G162), fall- out will enter the body through the digestive tract, through the lungs, or through wounds or abrasions. No direct absorptionthrough skin is reported in JCAES7, JCCRRERS6, G162, Cr56, or Du56. Beta burns appeared on the skin of Rongelap people many weeks after exposure; thus at the time of contamination we believe skin was intact. Harrison (Ha63) measured the extent to which gaseous Ig and aqueous solutions of Ki31y and 131y, were absorbed through human skin. For aqueous Ki311, the mean absorption rate was 7.8 x 1074 n@! and for 131, it was less. Use of stable I carrier with the gas was found to irritate and blister skin which may have led to the increased absorption reported for gaseous ly, (Ha63). We assumed 0.17 m* of skin surface was exposed, a skin surface ac~ tivity of 110 MBq m~2 (3.1 x 109 uci m2), and 49 hours of exposure at Rongelap Island. These assumptions led to an upper estimated intake of 0.7 MBq (19 uCi) I based on an absorption rate of 7.8 x 10~¢ h7!. This was an upper estimate since the skin surface was likely to be less contaminated than the ground sur- face because of swimming and bathing. Assuming that the urine bioassay results of Harris (Ha54) were accurate, we estimate the intake through skin to be as much as 20% of the total intake for 13!r. It was not likely that skin was as contaminated as the ground and, therefore, we do not consider this to be an important pathway. 3. Absorbed Dose for Individuals a. Absorbed Dose per Unit Activity Intake. Radioiodine and radiotellurium thyroid absorbed-dose commitment per unit activity intake and corresponding age were compiled in Table 21 from dose equivalent per unit intake results generated by Johnson (Jo81, Jo82). We performed an exponential interpolation of pre-adult values in order to generate ail the results given here. Thyroid absorbed-dose commitment was generated because all the nuclides of interest to us had half-lives much shorter than 50 years, the integration interval used by Johnson to generate committed dose equivalents. The values for the tellurium isotopes were generated from reference man data in Limits for Intakes of Radionuclides by Workers (ICRP79). The tellurium isotope values listed in Table 21 for the pre-adult ages were generated by ratios of the Johnson values for the appropriate iodine daughters. The thyroid absorbed dose for a person of any age per unit activity intake for tellurium was assumed to be directly proportional to the product of the adult value and the ratio of the iodine value. For example, 132Te rad per uUCi for a six-year-old (see Table 21) would be the product of 0.22 (taken from the 132Te column of Table 21) and the ratio of 0.048 to 0.013 (taken from the 1322 column of Table 21). rene yt; ted ul Li ow -37-