Svetlana N. Sushkova

Effect of the particle-size distribution on the adsorption of copper, lead, and zinc by Chernozemic soils of Rostov oblast

The parameters of adsorption of Cu2+, Pb2+, and Zn2+ cations by soils and their particle-size fractions were studied. The adsorption of metals by soils and the strength of their fixation on the surface of soil particles under both mono- and polyelement contamination decreased with the decreasing proportion of fine fractions in the soil. The adsorption capacity of the Lower Don chernozems for Cu2+, Pb2+, and Zn2+ depending on the particle-size distribution decreased in the following sequence: clay loamy ordinary chernozem ∼ clay loamy southern chernozem > loamy southern chernozem > loamy sandy southern chernozem. According to the parameters of the adsorption by the different particle-size fractions (Cmax and k), the heavy metal cations form a sequence analogous to that obtained for the entire soils: Cu2+ ≥ Pb2+ > Zn2+. The parameters of the heavy metal adsorption by similar particle-size fractions separated from different soils decreased in the following order: clay loamy chernozem > loamy chernozem > loamy sandy chernozem. The analysis of the changes in the parameters of the Cu2+, Pb2+, and Zn2+ adsorption by soils and their particlesize fractions showed that the extensive adsorption characteristic, namely, the maximum adsorption (Cmax), was a less sensitive parameter characterizing the soil than the intensive characteristic of the process—the adsorption equilibrium constant (k).

Effect of an attendant anion on the balance of cations in the soil-solution system with an ordinary chernozem as an example

The effect of different anions on the balance of heavy metal cations in the soil-solution system has been assessed under model laboratory conditions. It has been found that the uptake of the Cu, Zn, and Pb cations by an ordinary chernozem from solutions of different salts is accompanied by the displacement of the exchangeable cations to the solution in the following order: Ca2+ > Mg2+ > Na+ > K+. The sum of the displaced exchangeable cations in most cases exceeds the amount of the adsorbed heavy metal cations. According to the effect of the anions on the displacing capacity of the metal cations, the following series are formed: for copper, SO42− ≫ Cl− > OAc− > NO3−; for lead, Cl− ≫ NO3− > OAc−; and, for zinc, SO42− ≫ Cl− ≫ OAc− > NO3−.

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.

Dynamics of benzo[α]pyrene accumulation in soils under the influence of aerotechnogenic emissions

The regularities of benzo[α]pyrene (BaP) accumulation and distribution in chernozems (Haplic Chernozems), meadow-chernozemic soils (Haplic Chernozems (Stagnic)), and alluvial soils (Fluvisols) affected by the aerotechnogenic emissions from the Novocherkasskaya Electric Power Station (NEPS) were studied on the basis of long-term (2002–2011) monitoring data. A 5-km-wide zone stretching to the northwest from the electric power station and coinciding with the predominant wind direction was found to be most contaminated, with the maximum accumulation of BaP at about 1.6 km from the source. The coefficients of vertical BaP distribution between the layers of 0–5 and 5–20 cm closely correlated with the contents of physical clay, clay, and humus, and with the cation exchange capacity. The content of BaP in soils was shown to be indicative of the level of technogenic loads related to the combustion products of hydrocarbon fuels.

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.

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.

Benzo[a]pyrene degradation and bioaccumulation in soil-plant system under artificial contamination

The involvement of benzo[a]pyrene (BaP) one of the most toxic polycyclic aromatic hydrocarbons (PAHs) in the soil-plant system causes its potential carcinogenicity and mutagenicity for human health. The aim of this article is benzo[a]pyrene (BaP) degradation and bioaccumulation in soil-plant system under artificial contamination in model experiment with Haplic Chernozem and that spiked with various doses of BaP (20, 200, 400 and 800μgkg-1) equivalent to 1, 10, 20 and 40 levels of maximal permissible concentrations (MPC) planted with spring barley (Hordeum sativum distichum). The experimental soil samples were planted every spring and incubated outdoor during 4years. The express-method of subcritical water extraction was used for BaP extraction from samples. It was established the values of BaP period of semi-degradation in soil (T50, y) contaminated with 10, 20 and 40MPC deviated from 1.4 to 1.8years, while these values in low contaminated soils deviated from 2.9 to 5.4years. It was found the BaP concentrations in plants depended on initial BaP contamination and reduced simultaneously with diminish of BaP concentration in the related spiked samples. Growing of spring barley in the BaP spiked soils lead to BaP accumulation in plants. The bioaccumulation factors for BaP in roots and vegetative part of barley plants (BAFr and BAFv respectively) fluctuated within 0.035-0.065 and 0.015-0.025 respectively at the 1st season and then reduced about twice to the 4th season. Meantime those values in control soils vice-versa increased twice from 0.03 and 0.01 respectively.

Method for hydrophytic plant sample preparation for light and electron microscopy (studies on Phragmites australis Cav.)

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Method of determining loosely bound compounds of heavy metals in the soil

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Ecological evaluation of polymetallic soil quality: the applicability of culture-dependent methods of bacterial communities studying

PurposeThis work aimed to study the effect of long-term polymetallic contamination on the state and parameters of soil bacterial communities, including the abundance of different groups of culturable bacteria and the activity of nitrification.Materials and methodsMonitoring plots were located in the dry lake and surrounding area, which had been formerly used for the discharge of industrial waste. The soils in the 16 plots were characterized by extremely high levels of heavy metal pollution. This study evaluated the main soil physicochemical properties by various methods, total metal contents by X-ray analysis, mobile metal content by atomic absorption spectrophotometry, the abundance of chosen groups of culturable bacteria by inoculation on solid media, and nitrification activity from ammonium and nitrite oxidation rates.Results and discussionHigh adaptation capacity of microbial communities to long-term pollution was revealed through marked lack of decrease in the abundance of some of the bacterial groups in soils with high contamination levels. Among the bacteria determined by the colony count method, copiotrophic and spore-forming bacteria were the least sensitive to contamination, and actinomycetes were the most sensitive. The high levels of soil pollution with heavy metals had pronounced adverse effects on nitrification activity. The decrease in activity was strongly correlated with pollutant concentrations. The oxidation of nitrite was shown to be more affected by pollution that the oxidation of ammonium.ConclusionsSome groups and parameters of culturable microorganisms can be used for soil status estimation under pollution conditions even though they are only a small fraction of the microbial community. The most sensitive parameter was the nitrification rate, while the number of actinomycetes was found to be most promising parameter among the groups of bacteria determined by plate counts. The use of sensitive groups of culturable microorganisms for bioindication purposes is a method, which may provide a cheap and sufficiently reliable tool for large-scale soil monitoring studies.