Abstract
The article presents the results of determination of concentration and isotope composition of uranium in waters and ice of the Pamiro-Alai. The obtained experimental data are the background for studying of the regularities of the formation of the effluent of mountain rivers. This work is significant because of the studied region is transboundary and is under the interest of the neighboring countries. Sampling was carried out during fieldwork in 2016 under the USAID-Afghanistan PEER454 project. Determination of uranium isotopes was carried out using high-resolution alpha-spectrometry after radiochemical isolation and purification. The main objects of this study are Kyzylsu and Muksu rivers with their tributaries, as well as the ice of this region. Three genetic types were determined based on the obtained experimental data. The first type includes atmospheric precipitations and young ice (ice from the glacier of Lenin and a spring near the Ters-Agar passage). The second type of water is characteristic for waters having contact with uranium-enriched rocks (the estuary of Kashkasu river). The third type of water is waters of deep circulation with active water exchange in mountain ranges with a high uranium concentration (eastern springhead of the Kyzylsu river). The calculations showed that the main source of most of the studied water bodies are atmospheric precipitations.