sik , UNITED STATES ATOMIC ENERGY COMMISSION WASHINGTON, D.C. 20545 DEC 14 1973 WITHOUT ENCLOSURES/ATTACHMENTS CONFIRMED TO BE UNCLASSIRED Dr. Robert Conard Brookhaven National Laboratory Upton, New York 11973 BYDRGk SON.DATE 616-9F ,. AbD Dear Bob: You will recall that during our last meeting we agreed to pull from the files reports on past survey activities that may be helpful in planning the next field trip. There is a large amount of information that could be reviewed. Enclosure 1 contains such material developed in preparation for the 1970 AEC survey of Bikini that was conducted by the Division of Operational Safety. The first part was developed to compare the 1967 precleanup and 1969 post-cleanup survey results. The question at that time was whether anything found during cleanup would significantly change Phil Gustafson's predictions which had been used by the Ad Hoc Committee in making their recommendations. We were trying to determine if there were any areas where more data were needed. You can see from the comparison of external radiation levels that the 1967 results for Bikini Island would not be changed by the 1969 findings. On the other hand, for internal emitters, the 1969 samples indicate somewhat higher levels of 90Sr in Pandanus, Arrowroot, and Coconut Crab. If you want to review the data on this, it is published in SWRHL 1lir by Smith and Moore and in NVO-269-8 by Edward Held. Another question in our minds at the time of the 1970 Bikini survey was what exposures would occur if the Ad Hoc Committee's recommendations for measures to reduce exposures were not followed. Table V shows how Gustafson's estimates would de changed by updating the 1967 survey results with the 1969 samples, the effect of leaving crabs in the diet with no calcium supplement and conversely with a supplement, and the effect of no further precautions. The major increase in whole body and bone doses for the case of no precautions is due to 90Sr and 137Cs in Pandanus. One alleviating factor for the present is that there are no edible Pandanus in Bikini Atoll. However, such levels could occur if the precautions for planting this food are not taken and if a calcium supplement is not used. Also, note that the five-year bone dose could be almost four Galant asa ALoGulb Gabe, ~ 7 rT; Cma ps WEEE 7238 [310 Pe /9 y x