4 Finally, once strontium is ingested and absorbed into the blood, 705, disintegra- tions are evenly distributed in cortical and cancelous bone tissues. vidual was assumed to exhibit different 905 ingestion rates. ity ingestion rate was determined from urine data. Each indi- The daily activ- The prospective dose equiva- lent was determined with the assumption that ingestion of 905, ceased when the individual departed from Bikini Atoll. Disintegrations resulting from residual strontium-90 in bone post departure were calculated for an infinite post residence interval versus a fifty year period commonly chosen for radiation workers. The dose equivalent commitment, the sum of the retrospective and prospective dose equivalents, are listed in Table 41, Column 3. The retrospective and prospective dose equivalent resulting from the ingestion of 1376, have been calculated for members of the Bikini Atoll population. The symbols, constants and equations used are presented in Appendix C. Data used for these calculations were obtained from Tables 9 through 12 of this re- port. Because the 1376, body burden data dramatically increased between 1974 and 1978, constant and continuous uptake of 1376, could not be assumed. quently, Conse- the dose equivalent during the uptake interval was calculated using a monotonic increasing uptaxe regime. The total residency period, was divided into three intervals during which constant and continuous ingestion of Cs was assumed. 1976 These periods, January 1, to April 5, 1970 to December 31, 1977 and April 6 to August 31, 1975, January 1, 1978, were determined based on the bioassay data and the maturation period for vegetation planted in the early 1970's. It was also assumed that the initial 13766 body burdens of individuals returning to Bikini Atoll were at baseline levels. . . . . The prospective dose equiva- . lent was determined with the assumption that the ingestion of 13 137 . Cs ceased after