SLIDE 27 Estimated activity intake from cistern water. Based on 1) Bikini Ash radioiodine activity per unit area estimates, 2) a 20% release of iodine activity from fallout granules to cistern water and, 3) an average cistern water volume of 0.15 m, the radioiodine activity concentrations were estimated for cisterns located at Rongelap Island. These concentrations were in agreement with gross beta analysis of cistern water. Prior to evaculation of Rongelap, many weeks of drought were reported by Sharp (Sh57). In the weeks preceding the BRAVO contamination, water from cisterns was rationed to one pint cup per person eagh day (Sh57). Assuming this wording implies US liquid measure, then 470 cm” of water per person per day were distributed and regulated by village officials. This water was used to,make tea and coffee and was directly ingested (Sh57). cm of water were assumed to be taken with each meal. One hundred fifty At Rongelap Island, this was assumed to occur at 5.5 (lunch), 12 (dinner), 24 (breakfast), 30 (lunch), 38 (dinner) and 50 (breakfast) hours post detonation. These assumed cistern water intakes led us to estimate the ingested activity tabulated here. This was a conservative estimate of radioiodine activity intake from this pathway because all the activity in the liquid phase in the cistern was assumed to be due only to the iodine isotopes. ESTIMATED ACTIVITY INTAKE FROM CISTERN WATER Rongelap Island Nuclide Activity Intake", M Bq me 0.75 ag 0.14 sae L 1.0 131 I 0.41 I 0.078 “Normalized to exposure rate and fallout composition. 29