infants, children, and adults in 1974 (Robison et al., 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 197Cs_ and Sr. 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 in a person) is the product of several factors: 1 _ D« EG xlxftx TE? xd 0.693 where C; I, Th » 2. The radionuclide concentrations in the variousfoods. 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 consumptionof local foods at a contaminated atoll. Thus, the relative consumption of imported andlocal foods = the radionuclide concentration in food i, pCi/g, = the intake of food i, g/d, = the efrective half-life of the radionuclide, d, f; = the fractional deposition of the radionuclide in the body or d = the dose equivalent rate conversion constant for a unit activity in the body, rem/pCi. selected organ, unitless, The effective half-life, Te’, is the combina- tion of radioactive decay (T'e’) and biological elimination after ingestion (Ty ). This combination is Ty? = (TH. + T/Te ve or in terms of elimination constants, Ap =AR 4 Ap. Including Te’ and f, in an overall umbrella 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: 5000152 1. The diet—the g/d intake of various foods. is very important for estimating the daily intake of Sr and 137Cs. These four basic categories will be discussed and the results combined to indicate the relative © dose equivalent for infants, children, and adults. We will 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 anyatoll; only the daily intake of radionuclides, and consequently the magnitude of the dose, would vary among atolls 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 99Sr to help lay the foundation for the results.