BASIC FORMS OF METALS MIGRATION IN THE PRESENCE OF HUMIС SUBSTANCES IN SODA LAKES OF EASTERN TRANSBAIKALIA

Relevance of the research is caused by insufficient information on metals behavior in the presence of humic substances as a factor reducing their toxicity and bioavailability in saline lakes of Eastern Transbaikalia. The aim of the research is to identify basic forms of some metals migration in the presence of fulvic and humic acids in soda lakes of Eastern Transbaikalia using thermodynamic calculations. Objects: humic substances, metal ions, soda lakes of Eastern Transbaikalia. Methods: chemical analysis of soda lakes water samples: titrimetry, potentiometry, photocolorimetry, atomic absorption spectrometry, flame emission spectrometry, inductively coupled plasma mass spectrometry; thermodynamic modeling using the MINTEQ software package (Generic NICA-Donnan). Results. The paper introduces the chemical research results of natural water samples composition taken from soda lakes of Eastern Transbaikalia. The authors have carried out thermodynamic calculations using the MINTEQ software package, taking into account the presence of humic and fulvic acids in lake waters and determined the basic forms of some metals available. The paper demonstrates the dependence of organically and inorganically bound metal complexes formation on mineralization and pH, metals sorption selectivity by humic substances and authigenic minerals formation in soda lakes and introduces the lake waters saturation indices with respect to these minerals. It was determined that those minerals, which lake water is in equilibrium with and even supersaturated by them, are the main barrier against basic cations concentration in lakes considered. The number of metals bound to complexes and their positions in the rows are determined by the level of organic matter, their properties, together with basic geochemical parameters of the environment.