No 2 (2025)

The study of karst hazard associated with the suffusion is a very relevant topic for construction sites in Moscow upon performing engineering geological survey and developing means of protecting the territory. According to archival data, a site with an area of 4.9 km² in the north-west of the city belongs to “hazardous” category. Within this area, 42 karst sinkholes were recorded in the 20th century. In the article, the authors analyze the geological conditions of the site based on the study of more than 400 wells. The work attempts to find a connection between the parameters of the geological environment structure and the appearance of sinkholes. A map of the thickness of clay deposits overlying the karst horizon has been compiled. A new approach to zoning the territory according to the degree of karst hazard has been proposed, as a result of which the area of the territory classified as “hazard” is reduced to 2.50 km².

The Kamchatka area has significant hydrothermal resources — according to some estimates, up to 80% of the total mineral water in Russia. The main thermal mineral resources have been developed near the regional center of Petropavlovsk-Kamchatsky. At the same time, many hydrothermal resources located at a considerable distance from the regional center in ecologically clean areas are insufficiently studied. One of these areas is Bystrinsky district, located in the center of Kamchatka, where three hydrothermal fields have been explored and used for heating needs, i.e., Anavgayskoye (82°C), Bystrinsky (48°C), Essovskoye (78°C). According to the chemical composition of water in these field, calcium-sodium sulfate waters are similar in composition and mineralization (1.0-2.6 g/dm³). The purpose of the study was to search for radon in these fields. Information about the presence of radon in these fields was not previously found in publications. A preliminary assessment of the radon presence in the associated gas in the wells of Anavgaysky, Bystrinsky and Essovsky geothermal fields was carried out using the measuring complex “CAMERA-01” (NTC “Niton”) for monitoring radon. Sampling was carried out on coal sorption columns directly on the heads of production wells. The sampling time, the number of columns and the gas flow rate from the top of the wellhead were selected taking into account the maximum radon capture. As a result of measurements in the associated gas of production wells of geothermal fields, significant concentrations of radon were found somewhere. The measured radon activity at the coal of the “CAMERA-01” complex ranged from 0.4 to 233 Bq. The analysis of the micro-component composition (device — ICPE-9000 laboratory of the RGTC FEB RAS) showed an increased content of boron — 7.97 mg/l, strontium — 0.83 mg/l and molybdenum — 0.017 mg/l in the deposits. No dependence of radon activity in production wells on the chemical composition, depth of wells, etc., was found in the fields. The presence of radon in the wells of hydrothermal fields opens up prospects for the development of resort and sanatorium complexes in the Bystrinsky district, Kamchatka, Russia.

A full-scale survey of water bodies differing in origin and formation conditions was conducted in the upper reaches of the Kuban River and the basin of its main tributary, the Teberda River (about 90 observation points). The purpose was to determine typical and atypical levels of a wide range of impurities in water, to identify the real sources of impurities entering watercourses, their migration, spatial distribution of water bodies with increased concentrations, and possible associations of ingredients. Concentrations of major ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃^–, SO₄^2–, Cl^–) and ions of trace elements (F^–, Li⁺, Sr²⁺) were determined by capillary ionophoresis, trace elements (Al, As, Cr, Cu, Mn, Mo, Ni, Pb, Zn), by atomic absorption method with electrothermal atomization. Based on the data analysis by methods of order statistics, i.e. five-number summary with adding internal and external upper adjacent values, regional elevated, high and extremely high concentrations were distinguished and the distribution of relevant water bodies in the studied area using GIS was revealed. Spatial analysis has shown that in most cases, but not always, they coincide in location with ore occurrences and scattering plumes (As, Mo), zones of modern volcanism under the western peak of Elbrus (Al, Li, F, Mg, SO₄^2–), of pyritization (SO₄^2–), zones with prevalence of sedimentary carbonate and gypsum-bearing rocks (Ca, Mg, Sr, SO₄^2–). In most of the water bodies (50–75%) the concentrations of almost all components are below the river water clarks. They are so depleted of essential elements (F, Ca, Mg, K) that they do not meet the criteria of physiological usefulness for drinking water. Due to the large number of Cu–Zn and Pb–Zn deposits, manifestations and mineralization points, Zn concentrations in 80% of the observation points are higher than clark. In some water bodies, natural pollution of As, Al and Li reaches dangerous levels exceeding MPC of drinking water up to 5 times for Li, 8.5 times for Al and 14 for As and habitants and tourists use them for drinking. The risks increase against the background of a deficiency of the main cations inherent in these waters.

The article discusses the conceptual framework and the possibility of using safety barriers in the design of MSW landfills. Their existing classifications are evaluated, as well as the experience of their application at present. The article presents the safety concept based on a systematic description of various types of barriers (multi-barriers) using the example of barriers for MSW landfills. The international experience in using safety barriers, as well as their application in the design of MSW landfills in Russia, is considered. It is proposed to use on a wide scale the doctrine of geochemical barriers, which is an achievement of the Russian science. Options are considered for creating artificial geochemical barriers that have proven to be effective in neutralizing hazardous waste from the metallurgical and mining industries, allowing us to increase the effectiveness of geoenvironment protection and to reduce the cost of arranging landfills. A schematic diagram of the expected hazard assessment method, the so-called “bow tie” method is presented and the possibility of its application for assessing the risks of environmental impact on the landfill and the landfill on the geological environment is considered.

Thermal conductivity of some loose urban soils in Yekaterinburg has been studied using the needle probe method. The studied samples include weathering crusts of granitic and ultramafic rocks, quartz sand and crushed piezoelectric quartz. Humidity and granulometric composition have also been studied. An increase in humidity from 2–3% to 20–25% leads to an increase in thermal conductivity from 0.15–0.3 W m^–1 K^–1 to 1.2–2.0 W m^–1 K^–1. Most samples are characterized by an “S”-shaped dependence of thermal conductivity on humidity, including an initial section of slow growth in thermal conductivity, a section of a faster growth, and a flattening of the dependence as it approaches maximum saturation. For the analytical description of experimental data, the percolation-based effective medium approximation (P-EMA) was used. The approximation error was 0.08–0.26 W m^–1 K^–1. The “critical humidity” parameter in the P-EMA approximation determines the position of curve inflection. It has been established that the critical humidity increases with the growth of the finest fraction content, i.e., clay and silty loam. Data on the thermal conductivity of loose urban soils can be used in calculating heat exchange on urban surfaces, for example, in urban heat island studies.

During routine measurements of radon flux density for construction purposes in Moscow, the areas were found with abnormally high radon flux densities exceeding 400 mBq m^–2 s^–1. These values far exceed those average values around 24–40 mBq m^–2 s^–1 for local sandy and clay soils, which is compounded with the fact that the area under study doesn’t contain any active faults or natural soils rich in uranium. Therefore, the question arises, whether these high values are of technogenic or natural origin. This paper uses machine learning algorithms to find the answer to these questions. Machine learning algorithms including random forest trees and artificial neural networks were used to try and predict radon flux density anomalies on a city scale. Predictors used included maps of geodynamically active areas, lineaments, distances to heavy rail infrastructure such as metro tunnels and surface-level rail. Additionally, normal predictors of radon such as ²²⁶Ra concentration in soil, quaternary soil type and elevation were used for the predictions. Predictions were made for both anomaly-free and anomaly included datasets. Training data included radon flux data for Moscow with both anomalous and background values which included 931 data points, of which 112 was classified as anomalous (more than 400 mBq m^–2 s^–1). Based on the predictions obtained, factors which influence radon flux density and those that may produce anomalous values were underlined.