SLIDE 56 Intake estimates and dose equivalent. Adult average values for activity ingestion rate on day of return were calculated for all nuclides at Rongelap, Utirik, or Bikini. This information was used to estimate adult body—burden histories based on the assumption of declining continuous intake or increasing intake. The declining continuous intake equation provided us with a smooth bodyburden function for Rongelap and Utirik adults. The equation was a tool to provide retroactive body-burden estimates during the early years post-return to Utirik. Few direct measurements were made at this time. Biological variation and errors in the collection and analysis of urine samples introduced larger errors in body-burden estimates §han did direct whole-body counting. These variations result in indirect body burden deviating widely from the hypothetical curve. Sr measurements of In contrast the 137 ¢6 results fit the curve closely. The method use to fit the data was not chosen to minimize the weighted sum of squares of deviations of the body-burden estimates. Instead average values of initial intake Fase were selected to represent all the body-burden data. For Rongelap, the Cs body burdens varied from the fitted int gke function by a maximum factor of 1.7 and an average factor of 1.4; the “Sr body burdens varied from the fitted intake function by a maximum factor of 3 and an average factor of 1.6. These factors reflect the quality of fit for directly measured body burdens and urine-derived body burdens in general. The integral intake for 50 years and the committed effective dose equivalent were derived quantities which depended on knowledge of the fitted intake function for each population. The 50-yr interval chosen for internal intake represented the years 1957-2007 for Rongelap residents. For Utirik residents, the 50-yr interval represented the years 1954-2004. The committed effective dose equivalent was based on this cumulated intake. integral intake was for a 4.5 year period, 1974-1978, At Bikini the For the nuclide 1376, an age dependent retention function was incorporated into the fitted intake function. In the estimate of adult committed efféctive dose equivalent a body mass of 60 kg was used based on 28 years of adult body mass measurements. INTAKE ESTIMATES Declining Continuous Intake Increasing Intake COMMITTED EFFECTIVE DOSE EQUIVALENT Retention vs Age Body Mass 54