Microelements in the surface waters of the Malka River basin and geochemical features of the region

Abstract

Relevance. The study of the chemical composition of surface waters is a very urgent task both from the point of view of studying the migration of elements in the environment, and the possible presence of toxic trace elements. The aim of this work was to study the possible influence of geochemical anomalies located in the Malka River basin on the content of trace elements in soluble form in the surface waters of this area. Methods. Studies of the trace element composition of surface waters were conducted from 2013 to 2019. There are 6 sampling points located along the riverbed itself. Data on 13 tributaries and 7 springs are also provided. In these water bodies, we studied the content of 12 trace elements (Ag, Al, As, Cd, Cr, Cu, Li, Mn, Mo, Ni, Pb, Zn). The samples were taken during the period of intensive melting of glaciers. The content of heavy metals was determined by atomic absorption spectrometry. The content of lithium ions was determined by capillary ionophoresis. Results. The waters of the river in the study area are quite clean. The concentrations of arsenic aluminum, copper, molybdenum, and cadmium were very low. In the waters of the middle course of the Malka River and its tributaries, silver concentrations increased to 0.1-0.2 µ/ dm3 , which is in good agreement with the data on the presence of anomalies associated with the deposit of noble metals in this area. There is a clear link between the presence of elevated concentrations of lead and zinc in surface waters and sites with the presence of geochemical anomalies for these elements. In the area of the Malkinsky deposit of iron ores naturally alloyed with chromium and nickel there is an increase in the concentrations of these elements in surface waters. For manganese, there is a clear trend of a natural decrease in concentrations during the transit of water from the high-altitude zone to the plain. High concentrations of lithium in the waters of the upper reaches of the Malka River basin are associated with the Elbrus volcanic center.