Application of EPR dosimetry method for dose estimation among population of Stepnogorsk city, Republic of Kazakhstan, living close to the uranium-processing plant: preliminary results

The preliminary assessment of doses to residents of Stepnogorsk, Republic of Kazakhstan, including workers of the uranium-processing plant, located near this city, is presented in the paper. Radiation doses in the residents of Stepnogorsk and workers of uranium-processing plant were evaluated in comparison with the exposure to the population of Astana city, chosen as the control territory. The method of EPR dosimetry with human tooth enamel was used for dose estimations. Teeth samples were removed according to medical indications. The paper presents the first results of the study. In total 27 samples of tooth enamel collected among residents of Stepnogorsk city (including workers of uranium-processing plant) were analyzed. It was found that the difference between radiation doses of the samples of teeth collected among workers of uranium-processing plant and the residents of Stepnogorsk city (not being employees of this plant), and radiation doses among residents of the Astana city (control territory) is not statistically significant. The relatively high doses were found in four residents of Stepnogorsk city, who did not work the uranium-processing plant. In a course of individual questioning it was found that these individuals were not exposed to radiation for medical purposes. A possible reason of the estimated high values of individual doses may be migration of these individuals from different localities of Kazakhstan, located in the immediate vicinity of the Semipalatinsk nuclear test site, where they could be exposed to additional irradiation. The presented results were obtained in a frame of pilot study. The investigation will be continued as additional samples of tooth enamel will be collected according to medical indications.