Radon (222Rn) concentrations in groundwater and surface water in the mountainous areas of the northern Tien Shan and assessment of radiological impact on health (case study in the Ala-Archa river basin, Kyrgyz Republic).

This article focuses on a pressing issue in mountainous arid regions: the elevated levels of ²²²Rn in the natural environment. This phenomenon is related to the endogenous activity of mountainous regions, which gives rise to seismic activity, fluid dynamics and the occurrence of ore mineralisation. Among these areas, the Tian Shan region, which is mainly occupied by the Kyrgyz Republic, deserves special mention. This article presents the results of the calculation of the dose loads and the assessment of the potential radiological impact on the health of the population of different age groups from ²²²Rn contained in the waters of the Ala-Archa river basin (Kyrgyz Republic). To this end, radioecological and physico-chemical parameters in surface and groundwater were investigated. The highest concentration of ²²²Rn was observed in groundwater, with values ranging from 1.1 ± 0.5 to 139.2 ± 27.8 Bq dm^-3, with a mean value of 21.3 ± 4.3 Bq dm^-3. The results of the radon flux density studies led to the conclusion that the increased ²²²Rn content in the groundwater is of tectonic origin. Dose calculations showed that the mean annual total effective dose was below the WHO recommended reference dose of 100 μSv y^-1, except for groundwater for adults (107.86 μSv y^-1) and infants (165.98 μSv y^-1). The presence of surface water and groundwater with different 222Rn contents and the lack of radioecological studies indicate the potential for further research in the mountainous areas of the Tien Shan.