DIETARY-INTAKE EVALUATION AND DOSIMETRIC MODELING FOR THE TECHA RIVER RESIDENTS BASED ON IN-VIVO MEASUREMENTS OF SR-90 IN TEETH AND SKELETON

Explanations are given for the models and algorithms that are utilised to reconstruct the doses due to the incorporation of Sr-90 in the inhabitants of the Techa riverside villages. A model for the Sr-90 accumulation and excretion in the tooth enamel is employed to derive the relative intakes of Sr-90 in the years 1950-1959. The measurements of beta-ray activity on the surface of the front teeth of persons born between 1940-1959 are used to derive the relative intakes in different calendar years and the transfer functions to the tooth enamel as a function of age. This derivation is based on a non-linear optimisation algorithm, to fit the observed average count rates for different birth cohorts in a village. The data for the village of Muslyumovo are used as the reference data set. Absolute values of the strontium intake are derived from the relative values by a fit to the measurements of the Sr-90 body burdens that were performed after 1974. A model has been developed for the age-dependent metabolism of strontium in the skeleton. The computations in terms of this model are in reliable agreement with experimental data on strontium in man.