Potentially toxic elements in urban soils of the coastal city of the Sea of Azov: Levels, sources, pollution and risk assessment.

Coastal cities are major centers of economic activity, which at the same time has negative consequences for the environment. The present study aimed to determine the concentrations and sources of PTEs in the urban soils of Taganrog, as well as to assess the ecological and human health risks. A total of 47 urban and 5 background topsoils samples were analyzed by ICP-MS and ICP-AES. A significant excess of Cu, Zn, and Sb was noted in urban soils compared to the upper continental crust and average world-soil (1.7-2.9 times). Statistical analysis showed that the elements in soils were of geogenic, mixed and anthropogenic origin. According to the single pollution index (PI), the greatest danger of soil pollution was represented by anthropogenic elements, namely Cu, W, Pb, Zn, Cd, and Sn, the levels of which were increased in residential and industrial areas. The median contents of As, Mn, Cr, Sr, Mo, Sb, Cu, W, Pb, and Zn were 1.1-2.1 times higher, while Cd and Sn were 2.5 folds higher in the urban soils compared to the background ones. The total pollution index (ZC) showed that only 15% of the soils had high level of pollution, which is typical for the industrial areas. Overall ecological risks were negligible or low in 92% of soils, and were mainly due to elevated levels of Cu, Zn, As, and Pb. Non-carcinogenic risks to humans were mainly related to exposure to La and Pb. The hazard index (HI) values for all PTEs were less than ten, indicating that overall non-carcinogenic risk for adults and children was low-to-moderate and, moderate, respectively. The total carcinogenic risk (TCR) exceeded threshold and corresponded to low risk, with Pb, As, and Co being the most important contributors. Thus, the industrial activities of Taganrog is the main source of priority pollutants.

Phenolic Compounds of the Medicinal Plants in an Anthropogenically Transformed Environment.

In this article, the impact of an anthropogenically transformed environment on the content of pharmaceutically valuable biologically active compounds in medicinal plants is analyzed. The studied biologically active substances included phenolic compounds (flavonoids, anthocyanins, tannins, and phenolic acids). The number of transmissible forms of heavy metals (HMs), including cadmium, lead, and mercury, were discharged from factories that are present in the soil. Plants uptake these toxic metals from the soil. HM causes changes in the activity of the several enzymes such as phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI) and other enzymes. These enzymes play an important role in biosynthesis of phenolic compounds in medicinal plants. It has been demonstrated that plant materials possess high antioxidant potential due to their high phenolic content. As a result, the present review discusses a thorough investigation of anthropogenically transformed environment effects on the quantity of pharmaceutically valuable phenolic compounds in medicinal plants.

Fabrication of biochar derived from different types of feedstocks as an efficient adsorbent for soil heavy metal removal.

For effective soil remediation, it is vital to apply environmentally friendly and cost-effective technologies following the notion of green sustainable development. In the context of recycling waste and preserving nutrients in the soil, biochar production and utilization have become widespread. There is an urgent need to develop high-efficiency biochar-based sorbents for pollution removal from soil. This research examined the efficacy of soil remediation using biochar made from three distinct sources: wood, and agricultural residues (sunflower and rice husks). The generated biochars were characterized by SEM/SCEM, XRF, XRD, FTIR, BET Specific Surface Area, and elemental compositions. The presence of hydroxyl and phenolic functional groups and esters in wood, sunflower and rice husk biochar were noted. The total volume of pores was in the following descending order: rice husk > wood > sunflower husk. However, wood biochar had more thermally stable, heterogeneous, irregular-shaped pores than other samples. Adsorption of soil-heavy metals into biochars differed depending on the type of adsorbent, according to data derived from distribution coefficients, sorption degree, Freundlich, and Langmuir adsorption models. The input of biochars to Calcaric Fluvic Arenosol increased its adsorption ability under contamination by Cu(II), Zn(II), and Pb(II) in the following order: wood > rice husk > sunflower husk. The addition of sunflower husk, wood, and rice husk biochar to the soil led to an increase in the removal efficiency of metals in all cases (more than 77%). The increase in the percentage adsorption of Cu and Pb was 9-19%, of Zn was 11-21%. The present results indicated that all biochars functioned well as an absorbent for removing heavy metals from soils. The tailor-made surface chemistry properties and the high sorption efficiency of the biochar from sunflower and rice husks could potentially be used for soil remediation.

Soil organic matter and biological activity under long-term contamination with copper.

Organic matter (OM) and enzymes activity can act as indicators of the time and level of soil contamination with heavy metal. The goal of this study is evaluation of the effect of chronic long-term soil contamination with Cu on OM and biological activity in Spolic Technosols. The monitoring plot is located in the zone of industrial wastewater storage and sludge reservoirs in the Seversky Donets River flood plain. The total amount of Cu in the investigated soils varied greatly from 52 to 437 mg/kg. The results of Cu sequential fractionation the contaminated soil have shown that the chemical fraction composition of metal changed when the soil contamination level increased. The amount of Cu compounds associated with OM and Fe and Mn oxides was also higher. Fractions of OM from the humic and fulvic acids groups were studied. Soil was subjected to extraction with cold and hot water, and the content of water-soluble OM (WSOM) was determined. An increased solubility of humic and fulvic acids as well as elevated content of cold and hot extraction WSOM was established. The cold-extracted amount of WSOM increased with an enhance in the Cu content. The long-term contamination of soil with Cu leads to an adaptation of microorganisms to this adverse environmental factor, and this adaptation is manifested in the WSOM content increase. The effect of Cu contamination on microbiological activity was assessed by plate-counting culturable microorganisms and determining urease and dehydrogenase enzymatic activity. A high level of soil contamination with Cu showed a noticeable negative effect on the number of soil bacteria; however, active and potentially active bacteria were observed even in the highly contaminated soils. The changes in soil OM and microbial communities caused by Cu pollution can lead to disruption of ecosystem functioning.

Geochemical transformation of soil cover and vegetation in a drained floodplain lake affected by long-term discharge of effluents from rayon industry plants, lower Don River Basin, Southern Russia.

Lake Atamanskoye is one of the most polluted aquatic environments in the South of Russia. This water body was affected by long-term pollution by effluent from industrial rayon plants located in the city of Kamensk-Shakhtinsky. Accumulation of pollutants resulted in the degradation of Lake Atamanskoye, which is currently drained. This research focused on the geochemical transformation of soils and vegetation within the territory of the former water body and its surroundings. Methods of study included the evaluation of potentially toxic elements (PTEs) in soils and plants by X-ray fluorescence, as well as the contents of their forms by sequential extraction and statistical processing of the data. The results revealed that Spolic Technosols and Fluvisols represent the most widespread soils within Lake Atamanskoye. The concentration of metals found in the soils of the lakebed is several orders of magnitude higher than the regional geochemical background and world soil baseline values due to long-term industrial pollution. The natural and technogenic soils were subdivided into two groups according to pH. Alkaline soils in the presence of carbonates were characterised by high levels of PTEs, while acidic soils with higher proportions of exchangeable fractions and higher potential for metal accumulation in adjacent plants had lower levels of PTEs.

Metal-Based Green Synthesized Nanoparticles: Boon for Sustainable Agriculture and Food Security.

The applications of metal-based nanoparticles (MNPs) in the sustainable development of agriculture and food security have received greater attention in recent years in the science community. Different biological resources have been employed to replace harmful chemicals to reduce metal salts and stabilize MNPs, i.e., green methods for the synthesis have paid attention to the nanobiotechnological advances. This review mainly focused on the applications of green synthesized MNPs for the agriculture sector and food security. Because of the novel domains, the green synthesized MNPs could be helpful in the different areas of agriculture like plant growth promotion, plant disease, and insect/pest management, fungicidal agent, in food security for food packaging, for increasing the shelf life and protection from spoilage, and other purposes. The global scenario of the recent studies on the applications of green synthesized MNPs, particularly in sustainable agriculture and food security, is comprehensively discussed.

Effects of Zinc Oxide Nanoparticles on Physiological and Anatomical Indices in Spring Barley Tissues.

The aim of the present work was to investigate the toxic effects of zinc oxide nanoparticles (ZnO NPs, particle size < 50 nm) on the physiological and anatomical indices of spring barley (Hordeum sativum L.). The results show that ZnO NPs inhibited H. sativum growth by affecting the chlorophyll fluorescence emissions and causing deformations of the stomatal and trichome morphology, alterations to the cellular organizations, including irregularities of the chloroplasts, and disruptions to the grana and thylakoid organizations. There was a lower number of chloroplasts per cell observed in the H. sativum leaf cells treated with ZnO NPs as compared to the non-treated plants. Cytomorphometric quantification revealed that ZnO NPs decreased the size of the chloroplast by 1.5 and 4 times in 300 and 2000 mg/L ZnO NP-treated plants, respectively. The elemental analysis showed higher Zn accumulation in the treated leaf tissues (3.8 and 10.18-fold with 300 and 2000 mg/L ZnO NPs, respectively) than the untreated. High contents of Zn were observed in several spots in ZnO NP-treated leaf tissues using X-ray fluorescence. Deviations in the anatomical indices were significantly correlated with physiological observations. The accumulation of Zn content in plant tissues that originated from ZnO NPs was shown to cause damage to the structural organization of the photosynthetic apparatus and reduced the photosynthetic activities.

The Effect of Granular Activated Carbon and Biochar on the Availability of Cu and Zn to Hordeum sativum Distichum in Contaminated Soil.

The presence of heavy metals in the soil could impose serious problems on soil-plant systems due to the accumulation of heavy metals in plants. Even vital elements such as Cu and Zn have a toxic effect in the case of excessive intake by living organisms. The present work aimed to investigate the content of loosely bound (exchangeable, complexed, and specifically sorbed) compounds of Cu and Zn and their availability to spring barley (Hordeum sativum distichum) in contaminated Haplic Chernozem soil under the conditions of a model experiment (five approximate permissible concentrations (APC) and 10 APC of metal). Changes in the bioavailability of the metals upon application of carbon sorbents were observed. An increase in loosely bound metal compounds has been shown under conditions of soil contamination with metals (up to 57% of the total content). The increase in the availability of Cu in the soil was mainly due to the formation of complexed metal forms with organic matter (up to 17%). The availability of Zn was found to be associated with an increase in exchangeable (up to 21%) and specifically sorbed compounds (up to 27%). Granular activated carbon (GAC) and biochar have high sorption properties. A decrease in the content of loosely bound compounds of metals was established, especially in the most mobile forms such as exchangeable and complexed forms. The introduction of sorbents into the soil opened up a new venue for binding heavy metals in situ, eventually leading to a decrease in their bioavailability. The inactivation of Cu and Zn in the soil upon the application of sorbents led to a decrease in metal absorption by spring barley. The highest efficiency of biochar application was established at a dose of 2.5% and 5% in soil contaminations of 5 APC and 10 APC of Cu or Zn. The efficiency of the use of sorbents was more influenced by the dose of application than by the type of sorbent. There was no significant difference between biochar and GAC. Stabilization and inactivation of metals may improve soil fertility and plant growth.

Transformation of copper oxide and copper oxide nanoparticles in the soil and their accumulation by Hordeum sativum.

In recent years, the study of the influence of nanoparticles (NPs) on the environment has attracted much interest as nanotechnology is becoming the key technology of the future generation. The comparative studies on the effects of macro- and nanosized copper oxide (CuO) on plants rarely cover the state and behaviour of CuO in the soil-plant system. This work considers the transformation of CuO in Haplic Chernozem depending on the degree of dispersion and its toxic effects on spring barley (Hordeum sativum) growth. To investigate the transformation of the studied particles of metal oxide in the soil and plant, both chemical method of analysis and synchrotron radiation X-ray powder diffraction, X-ray absorption near-edge structure spectroscopy (XANES) and X-ray absorption fine-structure spectroscopy (EXAFS) were used. It was shown that CuO NPs underwent a stronger transformation due to the high reactivity of smaller particles. The Cu mobility was observed to increase within the soil profile as confirmed by the model pollution experiment. This is mainly due to the formation of complex forms of metal with organic matter. A dose of 300 mg/kg of macro- and nanosized CuO did not significantly affect the development and productivity of spring barley. The effect of high doses of macro- and nanosized CuO (2000 and 10,000 mg/kg) had a negative impact on the growth of spring barley. The application of nanosized CuO had a greater toxic effect than the macrosized CuO on the plants. The XANES and EXAFS data revealed that CuO NPs accumulated in the soil and plants. The linear combination fit shown that Cu atoms, incorporated into the plants, have environment typical of CuO. This indicates a high environmental risk when soil is contaminated with CuO NPs compared with its arrival as CuO.

Environmental and human health risk assessment of potentially toxic elements in soils around the largest coal-fired power station in Southern Russia.

The combustion of solid fuel at power plants pollutes adjacent areas with potentially toxic elements (PTEs), which increases risks to public health in the vicinity of these facilities. The proposed paper presents the results of a geochemical study of PTEs (Cr, Mn, Ni, Cu, Zn, Cd, and Pb) contamination in the vicinity of Novocherkassk Power Plant (NPP) as it relates to environmental and human health risks. The impact zone of NPP is pronounced for a distance of approximately 7 km northwest of the enterprise-the second largest coal power plant in Southern Russia. Data from monitoring sites lead us to conclude that spatial patterns of soil pollution are strongly influenced by the peculiarities of local atmospheric circulation, while the characteristics of soils within the study area play a secondary role. The highest levels of PTEs and their exchangeable forms exceed both regional background and sanitary and hygienic standards within a radius of 3 km to the west of the plant, which corresponds to a zone of soils contaminated with Cr, Ni, Cu, Zn, Cd, and Pb. The carcinogenic risk to human health slightly exceeds the permissible standard of 1 × 10-6 for soils in close vicinity of the enterprise due to the potential human intake of Ni, Cd, and Pb. The results of the health risk assessment indicate no noncarcinogenic risks for adults, while for children, they are low.

The toxic effect of CuO of different dispersion degrees on the structure and ultrastructure of spring barley cells (Hordeum sativum distichum).

Nowadays, nanotechnology is one of the most dynamically developing and most promising technologies. However, the safety issues of using metal nanoparticles, their environmental impact on soil and plants are poorly understood. These studies are especially important in terms of copper-based nanomaterials because they are widely used in agriculture. Concerning that, it is important to study the mechanism behind the mode of CuO nanoparticles action at the ultrastructural intracellular level. It is established that the contamination with CuO has had a negative influence on the development of spring barley. A greater toxic effect has been exerted by the introduction of CuO nanoparticles as compared to the macrodispersed form. A comparative analysis of the toxic effects of copper oxides and nano-oxides on plants has shown changes in the tissue and intracellular levels in the barley roots. However, qualitative changes in plant leaves have not practically been observed. In general, conclusions can be made that copper oxide in nano-dispersed form penetrates better from the soil into the plant and can accumulate in large quantities in it.

The influence of long-term Zn and Cu contamination in Spolic Technosols on water-soluble organic matter and soil biological activity.

Potentially toxic elements (PTE) pollution has a pronounced negative effect on the soil and its components. The characteristics of soil organic matter and the activity of soil enzymes can serve as sensitive indicators of the degree of changes occurring in the soil. This study aims to assess the effect of long-term severe soil contamination with Zn and Cu on water-soluble organic matter (WSOM) and the associated changes in the biochemical activity of microorganisms. The total content of Zn and Cu in the studied soils varies greatly: Zn from 118 to 65,311 mg/kg, Cu from 52 to 437 mg/kg. The content of WSOM was determined using cold and hot extraction. It was revealed that the WSOM, extracted with cold water is a sensitive indicator reflecting the nature of the interaction of Zn and Cu with it. With an increase in the Cu and Zn content, the amount of WSOM extracted with cold water increases due to rise in the complex-bound metal compounds associated with it. The content of complex-bound compounds Zn in Spolic Technosols reaches 50% of the total metal content. It is shown that one of the biogeochemical mechanisms of microorganisms' adaptation to metal contamination is clearly manifested by the increase in the content of WSOM. The precipitation of metal carbonates develops in the soil which reduces the mobility and toxicity of PTE. Due to this mechanism, a decrease in the activity of dehydrogenases and urease was not prominent in all studied soils, despite the very high level of pollution and the transformation of organic matter. The study of the relationship of PTE with the most easily transformed part of WSOM and the activity of soil enzymes is of great importance for an objective assessment of possible environmental risks.

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.

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

Method of determination of heavy metals loosely bound compounds in the soil was developed using three separate extractions. The group of loosely bound compounds of metals includes exchangeable, complexed, and specifically adsorbed forms. This method is available, rapid and not expensive. Extraction takes less than 24 h. Sample procedure preparation is simple, and the analysis consists of only three steps, which can be performed simultaneously. The parallel extraction gives reliable and reproducible results and provides a relatively complete idea of the metals mobility in the soil, their availability to plants, migratory capacity, and transformation. •Method is suitable for a wide range of heavy metals and soil types. From the obtained data, the content of loosely bound compounds of heavy metals and the coefficients of metals mobility in the soil can be calculated.•Method is suitable for estimation the microelement supply of uncontaminated soils. The content of elements in the 1 N CH3COONH4 extract characterizes the actual pool of elements, and their content in the 1 N HCl extract defines their potential pool in the soil.•The coefficient of mobility (Km) is calculated to assess the contamination of soil with heavy metals. Estimation criteria of Km for Haplic Chernozem were developed.

The effect of technogenic emissions on the heavy metals accumulation by herbaceous plants.

The effect of technogenic emissions on the input of Pb, Zn, Cd, Cu, Mn, Cr, and Ni into plants from the Poaceae and Asteraceae families has been studied. Soil and plant contamination by anthropogenic emissions from industrial enterprises leads the decreasing of crop quality; therefore, the monitoring investigation of plants and soils acquires special importance. The herbaceous plants may be used as bioindicators for main environmental changes. It was found that the high level of anthropogenic load related to atmospheric emissions from the power plant favors the heavy metal (HM) accumulation in herbaceous plants. Contamination with Pb, Cd, Cr, and Ni was revealed in plants growing near the power plant. Heavy metals arrive to plants from the soil in the form of mobile compounds. Plant family is one of the main factors affecting the HM distribution in the above- and underground parts of plants. Plants from the Poaceae family accumulate less chemical elements in their aboveground parts than the Asteraceae plants. Ambrosia artemisiifolia and Artemisia austriaca are HM accumulators. For assessing the stability of plants under contamination with HMs, metal accumulation by plants from soil (the bioconcentration factor) and metal phytoavailability from plants above- and underground parts (the acropetal coefficient) were calculated. According to the bioconcentration factor and translocation factor values, Poaceae species are most resistant to technogenic contamination with HMs. The translocation factor highest values were found for Tanacetum vulgare; the lowest bioconcentration factor values were typical for Poa pratensis.