Dr. J. L. Liverman 2 December 17, 1976 individuals. Dietary, work, travel and recreational characteristics of the sampled individuals should be accurately recorded. With regard to the second question, sources of possible contamination, the TTG Sf was presented a brief review of information on plutonium in the Bikini environment > and incomplete information on the dietary habits of the residents and sources of YGfood. The TTG recognizes the need for continued moni toring of air, soil, water, : Y y and foodstuffs for plutonium and other transuranics. \ y 3) “ « KK Bs. vA uJ . - 7 fe i . 7. ™ The third question regarding projected ‘levels of transuranics in the current A ~. we et‘1 residents and their descendants follows from the first two questions in that it ar is necessary to derive reliable estimates of the body burdens of the current / residents and determine the sources of intake--whether from worldwide fallout or from the Bikini environment. To do this adequately requires better models than now exist. A Lawrence Livermore analysis is inconclusive because the ICRP model used was developed for radiation protection purposes and is not necessarily valid for assessing body burdens from urine data or predicting body burdens from inhalation and ingestion routes. The TTG recommends that the available data be reexamined using an updated metabolic model to derive new estimates of current body burdens .. ‘+ To minimize the cost of this effort a long range plan is needed that will assure identification of any gradual or precipitous changes in levels of transuranics in these substances. Samples ( tL are required that will be truly representative of the air the residents breathe| earners and the food they eat. oe - uo o "Serene © ’ and to project future body burdens in current residents and their descendants. TTG does not believe in vivo counting offers much hope at the estimated current body burdens. The However, if the revised projections indicate body burdens attaining nanocurie levels, then in vivo counting of all residents is urged. The fourth question, regarding possible health risks, depends upon current and future body burdens of transuranics in Bikini residents. Data presented to the TTG suggests that the average burden is \ 200 pCi 239,240 Pu. Using risk factors in the BEIR and similar reports, estimates of the health risk associated with this level Pade of plutonium can be calculated. However, the TTG believes this would be premature and of no value in guiding decisions relative to the human occupation of the Bikini Atoil. Such estimates should not be attempted until the body burdens of the Bikini residents can be ascertained with confidence. Also, such estimates of possible health consequences must be done. in context with other possible radiation exposures, such as from the beta-~gamma radiation from fission products dispersed on Bikini. In considering these questions, the TTG felt somewhat handicapped in that a concise but comprehensive summary of information on Bikini was not available. Apparently Livermore, Brookhaven, HASL, the University of Washington and perhaps other Labs have collected data which could be useful in assessing the current levels of contamination on Bikini but also provide guidance in obtaining additional data. Sincerely yours, W. J. Bair, Ph.D., Chairman . Transuranium Technical Group WUB:mjs