rather insensitive to calcium intake unless it greatly exceeds 1.0 ¢ per day sous 4 or is less than 0.3 g per day (personal communication, B. G. Bennett and J. Harley). Therefore, the similar nature and the similar intake of Ca for the overall Marshallese diet relative to U.S. diets would indicate no major problems in applying the 90s; model to the Marshallese population. Using Spiers model the dose rate, Dj, to a small tissue filled cavity - in bone is calculated from the 90s, concentration in mineral bone. Then, from geometrical considerations, the dose rates to the bone marrow, Da, and to endosteal cells, Ds, are calculated, using the conversion factors Dm/Do = 0.315 and Ds/Do = 0.434 respectively. The conversion factors are those ‘quoted in UNSCEAR22 and are equivalent to a marrow dose rate of 1.4 mrad/yr per pCi/gmCa and an endosteal cell dose rate of 1.9 mrad/yr per pCi/geCe. These dose rates are determined directly and not by comparison to radius so that "rads" are equivalent to "rems." Since bone marrow is considered a blood forming organ (annual dose limit equals 500 mresi/yr) and endosteal cells are in the “other organ" category (annual dose limit equals 1500 mrem/yr), the bone marrow dose is the critical organ in bone (1CRP23) for 906, Exanple calculations of the model are given in Appendix» D. 137¢. and 6066 For 1376. and ©%o the wethods of ICRP2°12° ane KCRP2® as developed by Killough and Rohwer in their "INDOS' code 27 are used for the dose calculations. This code is used as published; however, the output is modified to show the body burdens for each year. in the Marshall Islands, For 1376. | which is of major importance the model consists of two exponential components - as 3) 5011110 - if a ~i, Arr Ge ON