infants, children, and adults in 1974 (Robison etal., 1975). . In this report, we discuss in more detail the methods for estimating the relative radiological dose to infants, children, and adults as a result of ingestion of 157Cs and 99Sr. We have included recent data on physiological parameters, dosimetry models, and diet. The total dose equivalent (D) from ingestion of a radionuclide to.a person (or an organ ina person} is the product of several factors: TY? De 2iCixlix fixxd 1. The diet—the g/d intake of various foods. — 2. The radionuclide concentrationsin the various foods. 3. The deposition and retention of the radionuclides in the body. 4. The dosimetry of the ingested radionuclides. The combination of the dietary intake and the concentration of the radionuclides in food items determines the intake of radionuclides. Consequently, the radionuclide intake is directly proportional to the g/d consumption of local foods at a contaminated atoll. Thus, the relative consumption of imported andlocal foods where C; I, = the radionuclide concentration in food i, pCi/g, = the intake of food i, g/d, Ty’ = the effective half-life of the fj d radionuclide, d, = the fractional deposition of the radionuclide in the body or selected organ, unitless, = the dose equivalent rate conversion constant for a unit activity in the body, rem/pCi. The effective half-life, Te, is the combina- tion of radioactive decay (TY?) and biological elimination after ingestion (Ty*). This combination is Te* = (Tya TH)Te n or in terms of elimination constants, Ap =AR 4 Ap. : Including Te? and f; in an overall umbrelia of “deposition and retention,” there are four- separate categories for which data must be available in order to estimate the dose to people from ingestion: is very important for estimating the daily intake ofSr and 137Cs. These four basic categories will be discussed and the results combined to indicate the relative dose equivalent for infants, children, and adults. Wewill use radionuclide concentration data in local foods at Rongelap Island at Rongelap Atoll as a specific example for the calculation. Moreover, the relative doses established by the methodology for the different age groups would be the same for any atoll; only the daily intake . of radionuclides, and consequently the magnitude of the dose, would vary amongatolls or islands within an atoll. Because of the anticipated diverse audience of scientists and laymen to whom this report will be distributed, we have included a significant literature review on the intake and distribution, the retention, and the dosimetry of 137Cs and 9°Sr to help lay the foundation for the results.