Tatiana Minkina

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.

Effect of attendant anions on the adsorption of zinc, copper, and lead by chernozem

The adsorption of Cu, Zn, and Pb from acetate solutions is accompanied by higher values of the affinity constants compared to the adsorption of the same cations from nitrate solutions. The observed differences are due to the formation of stable charged complexes of acetate ions with heavy metal cations, whose binding strength with the surface of soil particles is higher than that of free ions, and also due to the possible precipitation of poorly soluble metal compounds in a calcareous ordinary chernozem.

Translocation of heavy metals in soil-plant system

Different capacities of soils for heavy metal adsorption affects the absorption of heavy metals by plants. The present study was conducted to obtain quantitative information about the heavy metals forms in chernozem and chestnut soil and their translocation in barley.

Erratum to: Forms of Cu (II), Zn (II), and Pb (II) compounds in technogenically transformed soils adjacent to the Karabashmed copper smelter

Purpose The aim was to study Cu (II), Zn (II), and Pb (II) forms in technogenically transformed soils adjacent to the Karabashmed copper smelter.

Comparing two methods of sequential fractionation in the study of copper compounds in Haplic chernozem under model experimental conditions

PurposeIt is very important to obtain the information on the soils capacity to immobilize HMs and distribute them among soil components. The aim of this work was to study the fractional composition of Cu compounds in Haplic chernozem under model contamination conditions using different fractionation methods.Materials and methodsThe fractional composition of copper compounds in Haplic Chernozem artificially contaminated with copper acetate has been studied under model experimental conditions. General regularities and differences in the distribution of Cu forms in soils at the use of sequential fractionation by the Miller method modified by Berti and Jacobs (1996) and the Tessier method (Tessier et al. 1979) are revealed.Results and discussionThe differences are related to the metal affinity for specific carrier phases, as well as to the selectivity and extraction capacity of the reagents used in these methods. A significant increase in the most mobile exchangeable Cu fraction is observed in contaminated soils. Aluminosilicates and soil organic matter make the largest contribution to the adsorption and retention of Cu.ConclusionsThe Tessier method is more suitable for the separation of the total technogenic component from contaminated soils. The Miller method is more informative at the determination of loosely bound HM compounds because of the use of weaker extractants.

Isolation and Identification of Bacterial Strains from Decomposing Hazelnut Husk

ABSTRACT Composting is the microbial decomposition of materials that are biologically degradable. The structure of the initial organic materials differs from that of the decomposed materials in terms of C/N ratio and other related chemical properties. During the decomposition process, various microorganisms degrade intermediate organic products. The objectives of this study were to determine the bacteria enabling the degradation of hazelnut husks and some chemical properties of decomposing hazelnut husks, which are an agricultural waste. For that purpose, 1 m3 of hazelnut husks collected from hazelnut orchards were heaped on bare soil and left to decompose aerobically. The bacterial strains that utilize hazelnut husks were sampled periodically for 2 years. Thirty bacterial isolates were cultured; the majority of the bacterial isolates were affiliated with Actinobacteria, especially Streptomyces spp. with seventeen strains. The total N, pH, and electrical conductivity of the hazelnut husk heap increased significantly over the 2-year period, with the highest values obtained at the end of the study period. The initial C/N ratio was 55.7 and after the 24 months, the final ratio was 22.6.

Morphological and anatomical changes of Phragmites australis Cav. due to the uptake and accumulation of heavy metals from polluted soils

The effect of strong chemical contamination of soils on the growth and structure of reed (Phragmites australis Cav.) roots and stems has been investigated. Soils and plants on monitoring plots in the zone of industrial sewage tanks and sludge reservoirs in the city of Kamensk-Shakhtinskii (southern Russia) were studied. Polyelement pollution of soils on the studied monitoring plots was revealed, with exceedances of Clarkes in hundreds of times for Zn and Cd, in tens of times for Pb, and in several times for Cu, Ni, Cr, and Mn. An ecological-geochemical estimation revealed an extremely hazardous level of soil contamination HMs in total. It is shown that the high level of soil contamination decelerates the ontogenetic development of plants and decreases their morphometric parameters. Electron-microscopic study of plants revealed changes in the ultrastructure of cell membranes, as well as the main cytoplasmic organelles of root and stem cells (mitochondria, plastids, etc.). It is suggested that the revealed structural changes in epidermis and mesoderm under the impact of metals hamper the radial migration of fluid in the root from the peripheral parts. These changes are one of the reasons for the decrease in the level of nutrient uptake and translocation from roots to shoots.

Determining the speciation of Zn in soils around the sediment ponds of chemical plants by XRD and XAFS spectroscopy and sequential extraction

For a correct assessment of risk of polluted soil, it is crucial to establish the speciation and mobility of the contaminants. The aim of this study was to investigate the speciation and transformation of Zn in strongly technogenically transformed contaminated Spolic Technosols for a long time in territory of sludge collectors by combining analytical techniques and synchrotron techniques. Sequential fractionation of Zn compounds in studied soils revealed increasing metal mobility. Phyllosilicates and Fe and Mn hydroxides were the main stabilizers of Zn mobility. A high degree of transformation was identified for the composition of the mineral phase in Spolic Technosols by X-ray powder diffraction. Technogenic phases (Zn-containing authigenic minerals) were revealed in Spolic Technosols samples through the analysis of their Zn K-edge EXAFS and XANES spectra. In one of the samples Zn local environment was formed by predominantly oxygen atoms, and in the other one mixed ZnS and ZnO bonding was found. Zn speciation in the studied technogenically transformed soils was due to the composition of pollutants contaminating the floodplain landscapes for a long time, and, second, this is the combination of physicochemical properties controlling the buffer properties of investigated soils. X-ray spectroscopic and X-ray powder diffraction analyses combined with sequential extraction assays is an effective tool to check the affinity of the soil components for heavy metal cations.

Time effect on the stabilization of technogenic copper compounds in solid phases of Haplic Chernozem

We studied the regularities of Cu stabilization in Haplic Chernozem contaminated with easily soluble (acetates, nitrates, sulfates, chlorides) and poorly soluble (acetates, nitrates, sulfates, chlorides) metal compounds in a five-year model experiment were studied. A low contents of Cu loosely bound compounds (LBC) (no >5% of total content) unchanging over time were revealed in the uncontaminated soil, which is indicative of the stability of soil processes. The Cu LBC content decreased over time in the soils contaminated with easily soluble compounds and increased in the soils contaminated with poorly soluble compounds. In both cases, the contents of Cu LBCs after 5 years of incubation remained higher than in the original uncontaminated soil. The effect of the attendant anions on the Cu LBC content was more apparent under the Cu application of 2000 mg kg-1 than at 300 mg kg-1. An inverse process characterized by an increase in the concentration of Cu LBCs over time was observed in the soil contaminated with Cu orthophosphate and oxide. Soil contaminated with different Cu compounds results in soil acidification. According to the effect on the decrease in soil pH, the attendant anions form the following series: SO42- ≈ Cl- > NO3- > Ac- > PO42- > O2-, which correlates with the Cu LBC content. Thus, the stabilization of Cu compounds in the soil is affected by the attendant anions and the interaction time of the metal with the soil solid phases.

Toxicity of copper oxide nanoparticles on spring barley (Hordeum sativum distichum)

The rapid growth of copper oxide nanoparticles (CuO NPs) production and its abundant uses in many industries, and increasing release into an environment from both intentional and unintentional sources, create risks to spring barley (Hordeum sativum distichum), one of the most important staple food crop. Thereby, the aim of this study was to investigate the phytotoxicity of CuO NPs on H. sativum growth in hydroponic system. The CuO NPs inhibited H. sativum growth by affecting the germination rate, root and shoot lengths, maximal quantum yield of photosystem II, and transpiration rate. Structural and ultrastructural examination of H. sativum tissues using light, transmission and scanning electron microscopy showed effects on stomatal aperture and root morphology, metaxylem size and changes in cellular organelles (plastids, mitochondria), as well as in plastoglobules, starch granules, protoplasm, and membranes. The formation of electron-dense materials was noted in the intercellular space of cells of CuO NPs-treated plants. In addition, relative root length was one-third (35%) that of the control, and relative shoot length (10%) was also reduced. Further, the Cu content of roots and leaves of CuO NPs-treated plants was 5.7 and 6.4-folds higher than the control (without CuO NPs), respectively. Presented data were significant at p ≤ 0.05 compared to control. Conclusively, the results provide insights into our understanding of CuO NPs toxicity on H. sativum, and findings could be used for developing strategies for safe disposal of NPs.