Measurements of Sr-90 content in teeth of Techa River residents

MAYAK PA plant (Southern Urals, Russia) is an enterprise for production and reprocessing of weapon’s grade plutonium. Between 1949 and 1951 about 100 PBq of intermediate and low level liquid radioactive wastes were released into the Techa River. To estimate the radiation exposure of Techa River residents taken place in the past the EPR measurements of teeth enamel were performed. The cumulative dose obtained by EPR is due to both: external photons and internal Sr⁹⁰ incorporated in enamel and dentin. To provide estimates of enamel dose from Sr⁹⁰/Y⁹⁰ for Techa River residents the Sr⁹⁰ content in the teeth tissue was measured using new beta spectrometer. The sensitivity of the measurements of Sr⁹⁰ activity in teeth tissue samples of weight 0.2–0.3 g is 0.4 Bq with accuracy 25%.