SLIDE 53 Body burden history at Rongelap and Utirik. Adult average body-burden data and urine-activity concentration data were used as input quantities to equations which related them to activity intake rates. These input data were obtained from Conard's medical report (C056, Co58, Co59, Co60, Co62, Co63, Co67, Co70, Co75, Wo59) and from recent surveys performed by members of the BNL Safety and Environmental Protection Division. An equation was developed to relate the activity in the urine or whole bedy to the activity taken in by ingestion of contaminated food and fluids. To select an appropriate model for this relationship, we examined the bodyburden history and fhe higsgry of ggtivity in vegetation and soil. Activity concentrations of Cs, I and Sr in surface soil on Rongelap and Utirik Atolls were observed by us to decline with time at a rate greater than radioactive decay f5ga 1954 §8 the present (Ne77, Ne79, Br82). Activity concentrations of Cs and Sr in vegetation were observed to decline at a rate greater than that predicted by radioactive decay alone (Ne77, Ne79). Body burdens and urine activity concentrations were observed to increase rapidly and to decline slowly throughout the residence time of persons at Rongelap and Utirik Atolls (Co75, Le80b). These observations led to the selection of a declining continuous intake model. The lines fitting the declining continuous intake model at Rongelap are presented here. Measured results are plotted. The body burdens at Utirik were a factor of 2.6 times less than those at Rongelap for the period 1958 to 1984, ‘ —--—9 Fe-55 RONGELAP re} > —~-—e Cs-[37 Ls > a oO fee} fs)N z ul a x ee) wo fs)e o io! Toya TIME. PAST REHABITATION, days 51