Some peculiarities of metal migration in the aerobic and anaerobic conditions in the surface water bodies

Abstract

The results of research on metal migration (Mn, Cu, Zn, Pb, Cr) in the surface water bodies of the different type (the Kiev and the Kanev reservoirs of the Dnieper cascade, and Verbnoye and Telbin lakes of the Kiev city) in dependence on their oxygenous regime are considered. It was shown that the metal migration in the aerobic conditions is mainly directed from water thickness to bottom sediments. In contrast, the migration of metal compounds from bottom sediments in the anaerobic conditions is increased. Manganese is mostly in a form of free ions Mn2+ in the pore solutions, therefore, it migrates from bottom sediments in the greatest extent. The migration of other studied metals occurs in a much smaller extent and depends on the migration mobility of organic substances which they are bound to complexes. Migration mobility of copper, lead and chromium decreases essentially when the hydrogen sulphide is in the water of bottom layer. The data on a degree of metal binding to complexes and their chemical nature in water of reservoirs and lakes are given. The greater part of metals is found to be in complex compounds with humic substances in water of the Dnieper reservoirs, whereas in the lakes a share of neutral (mainly with carbohydrates) and cationic (mainly with protein-like substances) complexes essentially increases. The distribution of metals is explained by distinction in a component composition of dissolved organic matters in the reservoirs and in the lakes.