PILOT-STUDY OF THE URALS POPULATION BY TOOTH ELECTRON-PARAMAGNETIC-RESONANCE DOSIMETRY

During 1949-1956, about 76 x 10(6) m(3) of radioactive liquid waste co ntaining a total activity of 10(17) Bq was discharged into the Techa R iver by the first Russian industrial nuclear facility Mayak. As a cons equence, the population living in the river valley received considerab le internal and external radiation doses. The results of a first appli cation of electron paramagnetic resonance (EPR) of tooth enamel for a retrospective individual dose evaluation of the residents of the Techa riverside are presented. Three main contributions to the dose absorbe d in tooth enamel have been considered: external exposure mainly from the Techa River sediments, internal exposure mainly due to Sr-90; and background radiation including all other sources of exposure except th e Techa River. The teeth of 86 inhabitants of the town Kamensk-Uralski i were analysed to determine the age-dependent contribution of the bac kground radiation to the enamel dose. For 22 residents of the middle a nd lower Techa riverside, measurements of the Sr-90 whole-body content and EPR measurements of the absorbed dose in enamel were used to esta blish a correlation between these two quantities. Finally, absorbed do ses in the enamel of five residents of the upper Techa riverside were determined by the EPR method. Contributions of the background radiatio n and the internal Sr-90 contamination were subtracted to determine th e external exposure of the residents.