instead of the annual 3.65 pCi com- the inhalation pathway. puted from the reported data.” tonium concentrations reported for There If the plu- would, of course, be an additional urine samples from New York are contribution to urine plutonium levels accepted, the data suggest that the due to transport from deep-lung and parameters for transfer of inhaled lymph-node burdens of previous inhala- plutonium to blood must be consider- tion exposure. ably higher than those presently However, the magnitude of this contribution should be similar assumed. to that previously estimated for the percentage transferred from the New York and would therefore lead to upper respiratory tract to the blood total annual urine levels of approxi- and in the percentage transferred mately 0.015 pCi. from the blood to the urine that are The reported urine However, increases in both concentrations indicate an annual reasonable for physiological function urine level of 3.65 pCi. and chemical transport still cannot If we accept these reported urine con- account for 204 of the total annual centrations for Bikini, intake appearing in the urine. then it would Be- seem that the transfer coefficient cause of this seemingly large fraction across the gut for plutonium incor- of the total intake appearing in the porated in food products must be much urine, higher than 3 x 107°. if this human data indicates that However, the New York data indicate it is difficult to evaluate transfer to urine is greater for human that the major contribution to the populations than previously assumed plutonium urine concentrations is via from animal studies. Summary Bikini Atoll may be the only global Bikini population is correct, and the source of data on humans where intake estimated dietary intakes are reason- via ingestion is thought to contribute able, it appears that the transfer the major fraction of plutonium body across the gut wall of plutonium burden. incorporated into food products is It is possibly the best greater than previously expected. available source of data for evaluating the transfer of plutonium The New York data, where the major across the gut wall after being intake is via the inhalation. pathway, incorporated into biological systems. if accepted as reported also lead to. If the plutonium urine data for the altered conclusions regarding the -15- ee 5010235