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Antimicrobial properties of the new strains of micro-organisms isolated from natural sources of various ecological niches in the Moscow region and the Republic of Tatarstan were studied. Antifungal activity of isolates was detected in a test culture of toxin-producing microscopic fungi that can cause animal and plant diseases: Aspergillus flavus, Candida albicans, Fusarium oxysporum and Penicillium spp. Of the 46 studied micro-organisms of genera Bacillus, Lactobacillus, Lactococcus and Streptomyces isolates, there are four strains (Bacillus subtilis, Lactobacillus plantarum, Propionibacterium freudenreichii and Streptomyces spp.) that showed an ability to produce biologically active metabolites with a pronounced antimicrobial potential against phytopathogenic fungi metabolites. Based on the selected four strains, a Bacterial product LRV composition has been created. Scots pine, pedunculate oak and small-leaved linden seedlings with single and double foliar treatment and Bacterial product LRV at a concentration of 10 mL/L led to an increase in the growth of the aboveground part by 31.8, 51.9 and 25.4%, respectively, and the underground part by 25.0, 37.2 and 25.7%, respectively, compared to the control. The weight of seedlings at the end of the study exceeded the control variant by an average of 26.0, 44.0 and 78.0%, respectively. Plant protection Bacterial product LRV use did not have a significant effect on the group of molds that caused the powdery mildew and Schütte disease damage to trees. The Biological product LRV provided plant protection from fungal diseases caused by Lophodermium pinastri Chev. and Microsphaera alphitoides. [ABSTRACT FROM AUTHOR]

As objects for reforestation, the least studied are carbonate substrates, which have a number of specific features in terms of mineral composition, the exchange of nutrients, and biological activity. The use of biological preparations of a consortium of bacteria of the genus Bacillus and mycorrhizal fungi of the genus Glomus in growing seedlings of Scots pine (Pinus sylvestris L.) on carbonate substrates provides the metabolic products; soluble and microelement salts function as catalysts for chemical reactions of exudates and soil products; and a greater amount of plant heavy metals (HM) Cu, Zn, Cd, and Pb accumulate in the soil. Among HMs, the random factors most strongly determined an accumulation of Cd (the influence rate of random factors h2x = 34.6%) and Pb (the influence rate of random factors h2x = 21.7%) in the plants. A trend of all studied HMs higher uptake by the Cretaceous pine (Pinus sylvestris var. cretacea (Kalen.) Kom.) in comparison with the P. sylvestris ecotype is revealed. Against the biological preparation background of Biogor KM and MycoCrop®, a greater value of the HM's biological absorption in comparison with the option without biological preparations is noted. This process occurs against a background of a significant increase in the nitrification capacity in the chalk fine-grained substrate (soil aggregates < 1 mm in size), which is an indirect indicator of an increased intensity of microbiological processes. Spearman's correlation was noted between the coefficient of accumulation of Cu, Zn, Cd, and Pb in the dry matter of Scots pine (P. sylvestris) seedlings and the nitrification capacity of substrate (rs = 0.610–0.744, p < 0.05), as well as the relationship between the nitrification capacity index of substrate and the coefficient of biological absorption of copper, zinc, and cadmium (rs = 0.543–0.765, p < 0.05). No relationship was found between the coefficient of biological absorption of lead and other soil chemical property indicators. HM absorption by plants was random. No correlations have been established between an accumulation of HMs and a content of total nitrogen, an absolute value of nitrate nitrogen, a humus content, or a pH. The significance of the work is the possibility of providing reliable reforestation with Scots pine (P. sylvestris) and Cretaceous pine (P. sylvestris var. cretacea) on the chalk outcrops using the biological preparations Biogor KM, MycoCrop®, and BGT* methodology and ensuring soil phytoremediation from HMs. [ABSTRACT FROM AUTHOR]

The floodplains and seacoasts of southern Russia are characterized by urbanization, developed agriculture, and rapidly developing industries. Anthropogenic activity leads to the long-term release of pollutants into the environment, which threatens the stability of ecosystems and public health. The study aimed to assess the ecological and human health risks posed by potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in the topsoils of the Taganrog Bay coast and the Lower Don floodplain. Concentrations of PTEs and PAHs were measured using X-ray fluorescence and high-performance liquid chromatography, respectively. Except for the comparatively most toxic Cd, which ranged from low to moderate, ecological risk factors indicated a low risk for PTEs. The cumulative ecological risk of PTEs was low. Zn, As, Cd, and benzo[a]pyrene (BaP) were the most dangerous pollutants, with concentrations 1–2 orders of magnitude higher than the maximum permissible concentrations (MPCs). Mostly sandy soils were characterized by high and very high individual pollution since they have more stringent quality standards due to their lower resistance to contamination. Significant concern is caused by the total contamination of soils with PAHs. A comparison of the toxic equivalent quotient of PAHs with the MPC of BaP showed high or very high contamination in two-thirds of the samples. The non-carcinogenic risk for adults in the region was negligible, whereas the risk for children was low. Dermal contact with PTEs and PAHs contributed to a significant non-carcinogenic risk. Only the combined intake of pollutants poses a substantial risk for children. Over most of the research area, total carcinogenic risk surpasses the threshold, indicating a low risk, with As being the most important contributor. The results of the study showed that PAHs pose a greater potential ecological risk than PTEs, and the opposite trend was observed in relation to the risk of negative impacts on human health. In this regard, taking into account the combined influence of different types of components allows for a more comprehensive risk assessments. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are chemically recalcitrant carcinogenic and mutagenic compounds with primarily anthropogenic origin. The investigation of the effects of emissions from energy enterprises on soil microbiomes is of a high priority for modern soil science. In this study, metagenomic profiling of technogenic contaminated soils was carried out based on bioinformatic analysis of shotgun metagenome data with PAH-degrading genes identification. The use of prokaryotic consortia has been often used as one of the bio-remediation approaches to degrade PAHs with different molecular weight. Since the process of PAH degradation predominantly includes non-culturable or yet-to-be cultured species, metagenomic approaches are highly recommended for studying the composition and metabolic abilities of microbial communities. In this study, whole metagenome shotgun sequencing of DNA from two soils with varying PAH levels was performed. In the control site, the total content of 12 priority PAHs was 262 µg kg−1. The background soil levels in the polluted site for PAHs with 3 or more rings exceeded this, at 800 µg kg−1. The abundance of genes and taxa associated with PAH degradation in these two sites were estimated. Despite differences in PAH concentrations up to 1200 µg kg−1, individual and operon-organized PAH degradation genes were almost equally abundant and diverse in pristine and highly contaminated areas. The most numerous taxa in both spots were actinobacteria from Terrabacteria group. In addition to well-known PAH degraders such as Gordonia and Rhodococcus, genes corresponding to the PAH degradation were found in Azoarcus, Burkholderia and Variovorax. The data shows non-specificity and multifunctionality of metabolic pathways encoded in the genes of PAH-degrading microorganisms. [ABSTRACT FROM AUTHOR]

Due to anthropogenic activities, potentially toxic elements cause severe soil pollution worldwide. Therefore, remediation of contaminated soils is exigent and imperative. One cost-effective and environmentally friendly remediation approach is the application of biochar, which is a solid carbonaceous material. Biochar degrades slowly in soil and can persist there for thousands of years, according to various estimations. In addition, coal obtained from crop wastes has a developed porous structure, a high specific surface area, and does not contain toxic compounds such as heavy metals and polycyclic aromatic hydrocarbons. Biochar with optimal values for specific surface area and porosity was obtained from rice husk by stepwise pyrolysis. The pyrolysis parameters such as the heating rate (11 °C∙min−1), temperature (700 °C), and holding time (45 min) were established. At the same time, the surface area of the biochar increased by almost three times with a change in the pyrolysis conditions. As a part of this research, the efficacy of adsorption of Cu(II) from Haplic Chernozem using biochar made from rice husk was examined. The Langmuir and Freundlich models were employed to describe the adsorption data. The isotherm data of heavy metals was better fitted to the Langmuir adsorption model. The addition of rice husk biochar to the soil presented greater removal efficiencies of Cu(II) than soil in pure form. The analysis of the structural characteristics of the sorbent suggest that this material may work efficiently for the restoration of contaminated soil. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]