Formation and change of the water chemical composition along the bed of the transboundary pyanj river (tajikistan)

The hydrochemistry of the Pyanj River was investigated by sampling at ten points in the middle and lower reaches of the river between the geographical coordinates 37.92010N 71.40069E and 37.98391N 70.25198E. Physicochemical studies covered water samples from the summer and autumn periods, and the results were generalizations of the values of the concentration of chemical elements during these periods. The dynamics of changes in the concentration of cations and anions were established by comparing their values in the middle and lower reach of the river. The aim of research is the study of the hydrochemistry of the middle and lower reaches of the transboundary Pyanj River and the dynamics of changes in the chemical composition along the riverbed. Ten samples were taken at each sampling point to determine trace elements. Elemental analysis was performed in the United States at the Laboratory of Environment and Geology of the Department of Geological Sciences at the University of Colorado in Boulder and the wet chemistry Laboratory of the Institute of Arctic and Alpine Research using an inductively coupled plasma mass spectrometer (ICP-MS) and ion chromatography. To assess the relationship between the average values of indicators and various physical and chemical parameters, a Pearson correlation analysis was performed, the statistical significance of which was established at the level of P <0.05. Studies of the chemical composition of the Pyandj River in its middle and lower reaches have shown the determining role of weathering processes in the enrichment of river water with a wide class of chemical elements and the existence of their interrelationship, which was shown using Pearson correlation. In summarizing the results of the studies, it was shown that the dynamics of changes in the concentration of chemical elements along the riverbed is characterized by a decreasing trend with the manifestation of bursts of their concentrations in certain parts of the river. The manifestation of such an effect is primarily associated with the adjoining tributaries to the main water artery, the Pyanj River, which demonstrates their important role in the formation of the hydrochemistry of the main river. The processes of rock weathering are a key factor in the formation of the hydrochemistry of mountain rivers. The study of the chemical composition of rivers provides extensive information about the ecological state of water arteries and the geological structure of the area. Monitoring the hydrochemistry of rivers allows for a timely response to the appearance of pollutants and acts appropriately to neutralize their stationary sources.