The impact of the placer gold mining in Eastern Transbaikalia (Russia) on the environment components of river valleys in the Amur River basin

Based on the results of the analysis of satellite images and field observations, data on the length of the gold-bearing placers disturbed by the development along a number of main tributaries of the Shilka and Argun rivers are presented, the formed technogenic relief forms are indicated. Depending on the method of development, two types of technogenic landscapes have been identified - the excavation-dump with hydromonitor mining and belt trench-dump when washing with drags. The main directions of research on the assessment of placer gold mining in the natural complexes of river valleys are proposed.

The ecological and economic achievements in landscape optimization of technogenic reliefs

Mining and accumulation of industrial and household waste on the earth’s surface form the technogenic relief of the planet. The main forms of violation of the natural relief are quarries, ditches, landfills and spoil tips. There are two ways of landscape optimization in order to restore ecological balance, to turn the aggressive terrain into an ecological and economic value. The first is a return to the original natural landscape. The process is implemented by ground filling of technogenic depressions, removal and chemical and technological processing of waste accumulated at landfills and spoil tips. The second way is to use technogenic relief to form a new natural landscape. The main attention of the article is paid to the optimization of technogenic landscapes by forest plantations and forest reclamation. As a result of these activities, environmentally safe and aesthetically expressive spaces are formed. Most of these facilities have a high potential for economic, socio-economic and recreational use. The outstanding world achievements in this field are considered. Their ecological and economic characteristics are given.

Satellite monitoring of the state and dynamics of disturbed natural and technogenic landscapes in Siberia

A method for monitoring recovery process in post-fire and post-technogenic landscapes was proposed based on satellite data in wide spectral range including the infrared bands data. The spectral albedo in short-wavelength bands (MODIS band #1 and #2) was underestimated by 20–48% relative to the background in the first year after the wildfire and remained underestimated by 3–12% after 20 years of vegetation restoration. For the variant of post-technogenic plot with reclamation, the albedo value was corresponded to the dynamics in post-fire plots, while for post-technogenic dumps without reclamation the level of the albedo underestimation remained 45–60% throughout the observation period (> 60 years). A decrease in the spectral albedo of the surface in post-fire areas, due to destruction of on-ground vegetation, provokes excessive heating of surface and upper soil layer. Surface thermal anomalies were evaluated under conditions of changes in the heat-insulating properties of vegetation and ground cover. Temperature anomalies in post-fire plots (overestimation up to 30%) are typical for permafrost conditions of Siberia. Similar process was recorded for both natural (post-fire) and post-technogenic landscapes. Within 20 years of the fire, thermal insulation properties of the vegetation cover restore. Thus, the relative temperature anomaly has reached the background value of 3 ± 1%. In post-technogenic plots conditions are more “contrast” compared to the background, and restoration of the thermal regime takes significantly longer period (> 60 years). Forming “neo-technogenic ecosystems” are characterized with specific thermal regimes of soils compared to the background ones both for reclaimed and for non-reclaimed post-technogenic plots. In averaged, surface temperature has overestimated at least by 10–15% in post-technogenic plots.

The microorganism-plant system for remediation of soil exposed to coal mining

Introduction. Coal mining causes a radical transformation of the soil cover. Research is required into modern methods and complementary technologies for monitoring technogenic landscapes and their remediation. Our study aimed to assess soil and rhizosphere microorganisms and their potential uses for the remediation of technogenic soils in Russian coal regions. Study objects and methods. We reviewed scientific articles published over the past five years, as well as those cited in Scopus and Web of Science. Results and discussion. Areas lying in the vicinity of coal mines and coal transportation lines are exposed to heavy metal contamination. We studied the application of soil remediation technologies that use sorbents from environmentally friendly natural materials as immobilizers of toxic elements and compounds. Mycorrhizal symbionts are used for soil decontamination, such as arbuscular mycorrhiza with characteristic morphological structures in root cortex cells and some mycotallia in the form of arbuscules or vesicles. Highly important are Gram-negative proteobacteria (Agrobacterium, Azospirillum, Azotobacter, Burkholderia, Bradyrizobium, Enterobacter, Pseudomonas, Klebsiella, Rizobium), Gram-positive bacteria (Bacillus, Brevibacillus, Paenibacillus), and Grampositive actinomycetes (Rhodococcus, Streptomyces, Arhtrobacter). They produce phytohormones, vitamins, and bioactive substances, stimulating plant growth. Also, they reduce the phytopathogenicity of dangerous diseases and harmfulness of insects. Finally, they increase the soil’s tolerance to salinity, drought, and oxidative stress. Mycorrhizal chains enable the transport and exchange of various substances, including mineral forms of nitrogen, phosphorus, and organic forms of C3 and C4 plants. Microorganisms contribute to the removal of toxic elements by absorbing, precipitating or accumulating them both inside the cells and in the extracellular space. Conclusion. Our review of scientific literature identified the sources of pollution of natural, agrogenic, and technogenic landscapes. We revealed the effects of toxic pollutants on the state and functioning of living systems: plants, animals, and microorganisms. Finally, we gave examples of modern methods used to remediate degraded landscapes and reclaim disturbed lands, including the latest technologies based on the integration of plants and microorganisms.

CARAGANA ARBORESCENS LAM. AS A SHRUB SPECIES FOR BIOLOGICAL RECLAMATION OF POST-TECHNOGENIC AREAS

Minerals are considered one of the components of the economy of any country. The negative side of technogenesis is the emergence of technogenic landscapes with developed exogenous processes. To prevent and eliminate them, biological reclamation is carried out, the most promising direction of which is forest reclamation. In forest reclamation, preference is given to soil-improving tree and shrub species. The research was carried out in the stands of the Caragana arborescens (Caragana arborescens Lam.) on the dumps of the Kursk magnetic anomaly in the Belgorod region of the Central Federal District of Russia. The work on the test areas was carried out according to generally accepted methods. On the sandy-chalk dump of loose overburden, the karagany cultures completely died by the age of 38. On a two-component technozem, with surface application of a fertile layer on a sand-chalk mixture, karagana showed positive results. The maximum safety (84.2-82.0%) is typical for the first four years of karagana's life. It does not depend much on environmental conditions. The growth of shoots in karagana begins only in the second decade of May. Shoots grow most actively in the third decade of May - 43.8%. The average biomass of one karagana bush at the age of 6 years is 503 g. At the same time, the average mass of one specimen of Robinia pseudoacacia is 2264 g. The total supply of phytomass in the 9-year-old karagana plantation is 69.5 c/ha, which is 2.6 times less than in the robinia pseudoacacia plantation. The reclamation role of caragana leaves is insignificant. The tree-like karagana is rich in mineral elements, which is reflected in their accumulation in substrates. The reserves of nitrogen – 4.06% and calcium – 1.46% are especially large in Karagan. The dump is located in the mining production zone, so the iron content in the assimilating organs of karagany exceeds 4 times the content on zonal soils, and titanium - 1.8 times. A significant part of the chemical elements falls on the green parts of plants. Caragana leaves are supplied with: nitrogen - 26.64 kg /ha, potassium - 1.78 kg/ ha, calcium - 17.52 kg/ ha and magnesium - 4.56 kg/ha. More than half of the chemical elements of root systems accumulate in small roots. When they die off, they enter directly into the substrate. The tree-like karagana can be recommended for forest reclamation of technogenically disturbed lands when mixed with more valuable tree and shrub species

INDICATORS OF CHEMODESTRUCTIVE FRACTIONATION OF ORGANIC MATTER SOILS OF NATURAL AND ANTHROPOGENIC-TRANSFORMED LANDSCAPES OF THE SOUTH OF PRIMORYE

The differences in the qualitative composition of organic matter in the soils of natural and anthropogenically transformed landscapes in the south of Primorye were established by the method of chemodestructive fractionation (CDF). The lowest indices of the easily oxidizable part (EOP) in the organic matter are typical for soils of technogenic landscapes (embryozems) with very low humus content due to low reserves of aboveground phytomass and the supply of fresh organic matter of plant origin. Embryozems are characterized by a low supply of humus with nitrogen. Higher EOP values are characteristic of soils of natural landscapes (burozems) with average humus content. In burozems, oxidative and eluvial processes are balanced by humus formation. In the soils of agrogenic landscapes (agro-dark-humus podbeles, agro-dark-humus gley soils) with low humus content, the proportion of EOP decreased and, at the same time, the proportion of the hardly oxidized part in the composition of soil organic matter increased. Some increase in EOP was recorded in agro-dark-humus gley soils with rump crops, which is associated with the intensification of the transformation processes of organic matter and the transition of organic matter from the difficult-to-oxidize to the easily oxidized part. Based on the data obtained on the qualitative composition of organic matter, the CDF method implies that in the soils of natural landscapes (burozems), the proportion of EOP exceeded that in comparison with soils of agrogenic (agro-dark-humus podbely, agro-dark-humus gley) and technogenic landscapes (em-briozems). This indicates differences in the conditions of soil formation and the ongoing oxidative and humus-forming processes.

Comparative assessment of the use of humic substances derived from brown coals for technogenic landscapes reclamation

The objective of the study. To identify the prospects for the use of humic preparations for the restoration of disturbed coal-mining areas, by assessing the relationship between their biological activity and the structural-group composition. Location and time of the study. The study was carried out in the Novokuznetsk district of the Kemerovo region (N 54.14o N and E 87.10o E) in 2020. Methodology. The study of the structure-group composition of humic preparations was carried out by the 13C NMR spectroscopy. Evaluation of the effect of humic preparations was performed in a series of plot experiments setup in the reclaimed and non-reclaimed areas of the coal mining spoils. The properties of the soils substrates of the technogenic landscapes were determined by traditional soil methods. The effect of the preparations was assessed by the dry phytomass production and pod yields of Vícia villósa vetch, as well as the phytomass production of the Avéna satíva + Vícia villósa mixture. Statistical analysis of the data was carried out by the principal components analysis. Main results: Comparison of humic preparations obtained from brown coals of the Tisulsky (Kansk-Achinsky basin) and Tyulgansky (South Ural basin) deposits showed that, in general, all preparations positively affected phytomass production and pod yeild. However, in different conditions of technogenic landscapes and in relation to different plant species, the effect could manifest itself in different directions. A stable positive effect from pre-sowing seed treatment was achieved only with substrates depleted in natural humic substances (humus and peat), and with optimal moisture. Under such conditions, the greatest influence was exerted by preparations obtained from brown coals of the Tisulsky deposit of the Kansk-Achinsky basin, and their naturally oxidized form, which are characterized by a high proportion of oxygen-containing aliphatic (CO-Alk-O), as well as aromatic (СAr) groups. At the same time, under moisture deficit, the indicated chemical properties negatively affected the yield. In stony areas of technogenic landscapes, a positive effect was manifested only by preparations with a maximum proportion of aromatic hydroxide-containing groups (СAr-ОН). Enrichment of humic preparations with microelements (Zn and Cu) did not result in either positive or negative consequences. Conclusion. The use of humic preparations obtained from brown coals for restoring technogenic landscapes is justified only in areas composed of loamy rocks with a low content of humic substances of humus and peat. The noted multidirectional action of humates, which manifests itself depending on their structural and group composition, properties of substrates and plant species used at the biological stage of reclamation, indicates that using the same standardized preparations for the reclamation of various technogenic objects may not be reasonable.

Optimization of technogenic landscapes of the Crimea. Report 1. Quarries and pits

The main forms of anthropogenic relief formation (defensive ditches, mounds, canals, quarries, dumps, etc.) from the Neolithic to the present, which were marked by the presence of 152 abandoned and 137 active quarries on the territory of the peninsula, are considered. The basic principles and approaches to the reclamation of anthropogenic landforms are stated. Improvement options should be determined by the specific conditions of the technogenic landscape, as well as the suitability of the quarry for the intended use and the possibility of its transformation and, of course, the need of the ecosystem and society for an optimized object of the proposed type. The versions of optimization of open-pit workings during dry and wet rock excavation are considered. It is noted that in conditions of water shortage, preference should be given to the creation of reservoirs at the place of workings. The basic requirements for reclamation for agricultural and forest lands, the formation of sozological reserves by the formation of artificial reservoirs for various purposes: a reservoir to maintain ecological balance and preserve biological diversity (landscape-ecosystem function), a reservoir as a recreation area (recreational function), a reservoir as a source of drinking water (hydrological function), a reservoir for fish farming, including professional fishing (economic function). Possible approaches to optimization of quarries are discussed. An assortment of plant species suitable for creating coastal communities with a coastal protection function is presented.

Migration of 238U and 226Ra Radionuclides in Technogenic Permafrost Taiga Landscapes of Southern Yakutia, Russia

This article describes the features and migration patterns of natural long-lived heavy radionuclides 238U and 226Ra in the major components of the environment including rocks, river waters, soils, and vegetation of permafrost taiga landscapes of Southern Yakutia, which helped us to understand the scale and levels of their radioactive contamination. Different methods have been used in this study to determine the content of 238U and 226Ra in various samples, including gamma-ray spectrometry, X-ray spectroscopy, laser excited luminescence, and emanation method. It was determined that the main source of radioactive pollution of soil and vegetation cover, as well as surface waters in these technogenic landscapes, are the dumps of radioactive rock that were formed here as the result of geological exploration carried out in this area during the last third of the 20th century. The rocks studied were initially characterized by a coarse, mainly stony gravelly composition and contrasting radiation parameters, where the gamma radiation exposure rate varied between 1.71 and 16.7 µSv/h, and the contents of 238U and 226Ra were within the range 126–1620 mg/kg and 428–5508 × 10−7 mg/kg, respectively, and the 226Ra: 238U ratio was 1.0. This ratio shifted later on from the equilibrium state towards the excess of either 238U or 226Ra, due to the processes of air, water, and biogenic migration. Two types of 238U and 226Ra radionuclides migration were observed in studied soils, namely aerotechnogenic and hydrotechnogenic, each of which results in a different intraprofile radionuclide distribution and different levels of radioactive contamination. In this study, we also identified plants capable of selective accumulation of certain radionuclides, including Siberian mountain ash (Sorbus sibiricus), which selectively absorbs 226Ra, and terrestrial green and aquatic mosses, which accumulate significant amounts of 238U.