DISCUSSION The body-burden and urine data indicated a definite decline with time from the day of return atom ingestion rate for 137, S; for 2395, were uncertain but indicated a decline. 65 Zn, 60 Co and 90 Sr. The data These measurements of inter- nal levels of radionuclides used in conjunction with the declining continuous in- take equations provided an estimate of the total intake, the committed effective dose equivalent and the rate of decline of radionuclides in the overall diet. The data for directly measured body burdens at Rongelap Atoll were the best qual- ity data for determining derived quantities. Based on a declining continuous intake due solely to radioactive decay and the 1970 5556 adult average body burden for each atoll, an estimate of the daily activity ingestion rate for 2 Re on the day of return was calculated. this ingestion rate, it was estimated that Based on 55 Fe contributed a negligible amount to the total committed effective dose equivalent (see Table 4). The assumption that k=O for 37 Fe was made because sequential body-burden data were not available. Assigning k=2.0x10_ 3 aly the value determined for 60¢,, leads to an 35 r¢ committed effective dose equivalent of 2.3x10 ~ adults. 3 Sv (2.3x1072 rem) for Rongelap This is larger by a factor of 5 than the estimate for committed effec- tive dose equivalent based on k=0. Use of the body-burden extrapolation equation leads to the conclusion that 6525 could have been the major contributor to the ingested activity during the first year post rehabitation of Utirik Atoll (see Table 4). This was supported to some extent by a Japanese report (JCCRRERS6) which indicated a rise in the photon count rate at the surface of various types of tuna retrieved from the Marshall Islands' fishing grounds from March to August 1954 (100 cpm to 10,000 epm). Fish with count rates greater than 100 cpm at the surface were discarded. 20