G. V. Motuzova

Forms of heavy metal compounds in soils of the steppe zone

A parallel scheme of extractions was used for determining heavy metal compounds in uncontaminated and artificially contaminated soils of Rostov oblast. A method for calculating the contents of complex and specifically adsorbed metal compounds from the difference in their concentrations in different extracts was suggested. It was found that the portion of firmly fixed metal compounds decreases and the portion of potentially mobile (exchangeable, complex, and specifically adsorbed) metal compounds increases with an increase in the degree of contamination of chernozems and chestnut soils with lead, copper, and zinc over a one-to two-year-long observation period. This was due to the capacity of heavy metal ions to substitute for the exchangeable cations in the exchange complex of the studied soils, to form complexes with the soil organic matter, and to participate in the specific adsorption. Some differences in the behavior of different metals were found.

Combined approach for fractioning metal compounds in soils

A combined approach for fractioning metal compounds in soils on the basis of sequential and parallel extractions is proposed. This approach has been used to assess the group composition of Zn, Cu, and Pb compounds in an ordinary chernozem and its changes upon the soil contamination with metals. The contents of firmly and loosely bound metal compounds that are presumably fixed by the particular soil components (organic substances, carbonates, and silicate and nonsilicate minerals) have been determined.

Interaction of heavy metals with the organic matter of an ordinary chernozem

Lead, copper, and zinc interacted with the soil organic matter when applied to an ordinary chernozem in a pot experiment. Two years after the treatment, an appreciable part of the metals applied was found in the organic substances, predominantly in a loosely bound state. These organic substances were supposed to be organomineral complexes, the formation of which resulted in the partial destruction of humic acid molecules. These processes increased the content of aliphatic structures and the share of fulvic acids and decreased the content of humic acids in the organic matter of the chernozem.

Fractional and group composition of the Mn, Cr, Ni, and Cd compounds in the soils of technogenic landscapes in the impact zone of the Novocherkassk Power Station

The compounds of Cr, Ni, Mn, and Cd in the soils around the Novocherkassk Power Station and the influence of the technogenic and natural factors on their composition were investigated. The data on the fractional and the group composition of these compounds proved to be informative for assessing the ecological state of the soils. The soil components specifying the accumulation and the properties of the heavy metal compounds in the polluted and unpolluted areas were identified.

Group composition of heavy metal compounds in the soils contaminated by emissions from the Novocherkassk power station

The effect of natural and technogenic factors on the mobility and transformation of metal compounds was studied from an analysis of the fractional-group composition of Cu, Zn, and Pb compounds in the soils of areas adjacent to the Novocherkassk power station. Changes in the composition of Cu, Zn, and Pb compounds in the soils of technogenic landscapes were estimated. The effect of aerosol technogenic emissions on the mobility of metal compounds was revealed; a higher metal mobility was found in soils with low buffering capacity. Common and specific features of the formation of Cu, Zn, and Pb compounds in soils were determined. The role of individual soil components in the retention of metals in clean and contaminated soils was established.

Erratum to: “Fractional and group composition of zinc and lead compounds as an indicator of the environmental status of soils”

An ordinary chernozem artificially contaminated with Zn and Pb salts and reclaimed by the addition of chalk and glauconite under pot experimental conditions has been analyzed. The fractional and group composition of the metal compounds in the soil extracts have been determined according to an original combined fractionation procedure. Coefficients characterizing the changes in the environmental status of the metals under the reclamation conditions have been proposed for describing the formation tendencies of the metal composition in the soils. These are the mobility coefficients (MCs) of the heavy metals (HMs) in the soils and the stability coefficients (SCs) of the soils for the HMs. They are calculated from the analysis of the fractional and group composition of the metal compounds. The MC characterizes the environmental vulnerability of soils to the impact of HMs; the SC characterizes the environmental sustainability of soils concerning the contamination with HMs. The obtained experimental data characterize the behavior features of Zn and Pb in the studied soils. An increase in the environmental hazard has been revealed at the contamination of soils with HMs, as well as its decrease at the application of the tested ameliorants. The participation of both strongly and loosely fixed HM fractions in the development of the HM mobility in the soils and the sustainability of the soils to their impact has been shown.

Composition of lysimetric waters from soils of the Upper Volga landscapes

The results of six-year-long observations of the chemical composition of lysimetric waters from soils of three biogeocenoses (forest, meadow, and agrocenosis) in the vicinity of the Ivan’kovo water reservoir were analyzed. It was found that the lysimetric waters of in the three biogeocenoses belonged to the class of fresh calcium-bicarbonate waters. Some differences in chemical compositions of these waters were identified; these differences were due to the impact of biogenic, lithogenic, and anthropogenic factors on the soils in which these waters were formed.

Sorption and migration of zinc in taiga zone soils in laboratory and field experiments

The parameters of the zinc sorption and migration were experimentally determined under laboratory and field conditions for soils of forest and meadow biogeocenoses of Tver’ oblast. Two methods gave relatively close values for the parameters of the metal’s sorption by an almost neutral loamy sandy soddy soil of a meadow biogeocenosis. The potential capacity of an acid sandy loamy soddy-podzolic soil for zinc sorption determined under laboratory conditions was not completely realized under the field conditions, which was related to the properties of the biogeocenosis (the forest plants, the organization of the soil pore space, and the soil reaction) and the experimental conditions.

The effects of iron, mercury, and copper ions on the acid-base properties of aqueous soil extracts

This article presents indicators of the influences of salts of iron, mercury, and copper on the acid- base properties of aqueous extracts from the upper soil horizons of taiga zones. Their acidification is estab- lished; under the influence of metals, the processes responsible for elevated levels of protons in the extracts are identified, viz., the hydrolysis of metal ions and their inclusion in the complexation with water-soluble organic substances. We discovered the effects on these processes of organic materials of the extracts, as well as of the properties of metals and the type and amount of salts, in whose composition the metals are included in the extracts.

Comparative characterization of humic acids from arable soils of the taiga, steppe, and semidesert zones

The parameters of the elemental composition, molecular weight distribution, infrared and proton spectroscopy, and hydrophilic-hydrophobic properties were determined for humic acids preparations isolated from arable horizons of soils from different natural zones (an ordinary chernozem, a soddy-podzolic soil, and a meadow sierozem). The general and specific properties of the humic acids from the three studied soils were revealed.