N. E. Kosheleva

Ecological-geochemical state of soils in Ulaanbaatar (Mongolia)

Based on the results of the soil-geochemical survey, the assessment of the soil cover pollution in different Ulaanbaatar functional zones is given. The soils of the industrial and traffic zones concentrating a wide spectrum of pollutants (Zn, Mo, Cr, Cr, Cd, Pb, and Cu) are characterized by the strongest technogenic transformation. The soils of the residential areas accumulate Pb and Zn, while those of the recreation zone, Mo, Ni, and Cr. The geochemical mapping allowed distinguishing four groups of elements with similar distribution patterns determined by the common pollution sources, the specific features of the parent rocks, and the intensity of the migration. Among the natural and technogenic factors responsible for the accumulation of microelements in soils, the basic ones are the soil physical and chemical properties: the contents of organic matter (for As, Cd, Cu, Mo, Zn), physical clay (Ni, Co), sulfates (Pb, Sr), and the pH (Cr). The character of the land use noticeably affects the concentration of many elements. The soils of the city are assessed as weakly polluted (Zc = 11). The contents of As, Zn, Mo, and Pb exceeded their MPC in 100, 34, 20, and 16% of the city’s territory, respectively. As compared to the state of the soil cover in 1990, no significant changes were revealed.

Factors of the accumulation of heavy metals and metalloids at geochemical barriers in urban soils

The bulk contents and concentrations of mobile (extracted by an ammonium acetate buffer with EDTA) Cd, Pb, Sb, As, Bi, Zn, and Cu were determined in the surface horizons of urban soils in the Eastern administrative okrug of Moscow. The regression analysis showed that the accumulation of these metals and metalloids in the soils is controlled by the physicochemical soil properties and by number of anthropogenic factors and landscape conditions (geochemical position, type of loose deposits, character of land use, dust load, vehicle emissions, building pattern, percent of green areas, and the extent of sealed soils). The precipitation of studied elements on the geochemical barriers had the following regularities: Cd, Cu, and Zn accumulated on the alkaline barriers; Bi, Sb, As, Cu, Pb, and Zn, on chemisorption barriers; Sb, As, and Pb, on organomineral barriers; and Cd and Cu, on the sorption-sedimentation barriers. Technogenic transformation of the physicochemical properties of urban soils resulted in the increase of the mean bulk contents of heavy metals and metalloids by 33–99%; the portion of elements fixed on the geochemical barriers increased by 26–50%.

Long-term dynamics of the anthropogenic salinization of soils in Moscow (by the example of the Eastern district)

The long-term (1989–2010) and seasonal dynamics of the anthropogenic salinization of soils related to the use of deicing mixtures in the Eastern Administrative District of Moscow were examined. Data on the chemical composition of deicing mixtures and on the contents of soluble salts in the snowmelt and in the soil profiles of different functional zones were analyzed. The maps of soil salinization were compiled for 1989, 2005, and 2010; on their basis, the resulting map of the degree of soil degradation was developed. The areas with abnormal concentration of salts in the soils expanded during the study period (21 yrs), and the average content of salts in such areas increased by 3.2 times. The maximum total content of salts was found in the spring season in the soils along major highways.

Polycyclic Aromatic Hydrocarbons in Urban Soils (Moscow, Eastern District)

The content and distribution of 17 individual structures of polycyclic aromatic hydrocarbons (PAH) were determined in the surface soil layers of the Eastern Administrative District of Moscow and in the background soils of the Meshchera Lowland. The maximum contribution to the PAH spectrum in the background soil belonged to the structures with a small number of nuclei mainly of natural genesis. In the urban soils, the mean total PAH was 5385 ng/g; it was 40 times higher than in the background objects. The unsubstituted multinuclear hydrocarbons as compared to homologues accumulated two times more intensely. The total PAH concentration in the soils of different functional zones varied from 4288 (old residential area) to 8655 ng/g (new blocks). The soils of each zone were characterized by a constant composition of polyarenes, which reflected a specific combination of pollution sources. Using the maps of the benz(a)pyrene contents in the soils in different years, two of its contrasting technogenic anomalies were revealed in the northern and central parts of the district. In 2006, in these areas, the benz(a)pyrene concentration exceeded its MPC by 150 times. The ecological hazard of PAH pollution was assessed. The estimate obtained took into account the carcinogenic potential of 13 individual polyarenes by their equivalents with respect to benz(a)pyrene.

Geochemical transformation of soil cover in copper–molybdenum mining areas (Erdenet, Mongolia)

PurposeThe aim of the present study is to evaluate geochemical transformation of soil cover in the territory of Erdenet (Mongolia) and to assess the environmental risk associated with soil cover contamination. The objectives of the present study included: (1) the determination of heavy metals (HMs) and metalloids contents in surface horizons of background and urban soils and the assessment of geochemical transformation of the city’s soil cover; (2) the identification of elements’ associations and patterns of their spatial distribution in the soil cover of the city; (3) the assessment of environmental hazard, related to contamination of soils with complexes of HMs and metalloids.Materials and methodsSoil–geochemical survey was conducted by the authors in the summer periods of 2010 and 2011. In total, 225 samples, including 32 backgrounds, were collected. Bulk contents of HMs and metalloids in soil samples were analyzed by mass-spectral method with inductively coupled plasma at All-Russian Research Institute of Mineral Raw Materials (Moscow) using Elan-6100 and Optima-4300 devices (Perkin Elmer, USA).Results and discussionMo, Cu, and Se appeared to be the priority pollutants nearly in all land-use zones. The maximum accumulation of Mo, Cu, Se, As, Sb, and W is restricted to the industrial area where total pollution index of soils (Zc) equals 74.8. Three technogenic associations of elements, derived mainly from petrochemical features of Erdenet ore field and characterized by similar spatial distribution within the city, are identified. Environmental assessment of surface soil horizon geochemistry in Erdenet showed that 1/5 of its area has dangerous and extremely dangerous levels of soil pollution.ConclusionsExperience of the environmental–geochemical assessment of soil cover in the impact zone of mining enterprises could be useful for other fields of the non-ferrous metals with high lithological–geochemical heterogeneity of the territory. It suggests the need of accounting for the geological diversity and specific features of metallogeny of an area. Geochemical indices local enrichment factor/local depletion factor should be calculated against the individual background values for each soil-forming rock. Such approach allows more accurate assessment of the degree of technogenic geochemical transformation of soils and the environmental hazard of pollution.

Trace Element Composition of Poplar in Mongolian Cities

Purpose. The aim of our work was to assess changes in the trace element composition of poplar leaves in large cities and mining centers of Mongolia. The objectives of the study included: (1) to reveal the biogeochemical background features and changes in the trace element composition of poplar leaves in urban and mining landscapes; (2) to determine the degree of technogenic disturbance in the chemical composition of urban vegetation; and (3) to assess the functioning and ecological status of poplars under technogenic impact. Materials and methods. Poplar hybrids, which compose about 75 % of the urban woody plantations, were sampled in Ulaanbaatar (77 samples) in the mid-summer of 2008, Erdenet (30 samples) in 2011, Darkhan (19 samples) in 2011, and Sharyngol (21 samples) in 2013. Bulk concentrations of 54 heavy metals in the samples of the dry plant material were measured by inductively coupled plasma mass spectrometry (ICP-MS) on Elan-6100 and Optima-4300 analyzers. Results and discussion. The local biogeochemical background of the Mongolian cities under consideration differs from the mean global values in the higher concentrations of Cd, Sr, As, and Zn. The concentrations of Be, V, Pb, Cr, and Ni in plants of the background areas are lower than their global values. The maximum coefficients of the biogeochemical transformation, Z v , were revealed in Ulaanbaatar. In the other cities, the values of Z v in the industrial zones were higher than those in the residential zones by 1.5–2 times. The trace element ratios characterizing the balance in the provision of metabolic processes confirm the conclusion about the satisfactory state of the urban trees.

Heavy metals in the air and snow cover of Ulan Bator

Field observations have been used to characterize air pollution in Ulan Bator by heavy metals during the 2008/2009 heating season. The degree of technogenicity of emissions and their main sources are determined. The diurnal and seasonal dynamics of atmospheric pollution are considered. It is found that many pollutants exceed maximum permissible concentrations (MPC). The most dangerous components in the urban atmosphere include Pb (up to 26 mean daily maximum permissible concentrations (MPCmd) and airborne particles (up to 21 MPCmd). The study revealed very high levels of total air pollution, especially in the center of the city (air pollution index (API) > 50)). Soluble forms of heavy metals as contained in the snow are characterized by a maximally high degree of pollution hazard for the urban environment, with a low degree corresponding to solid-phase depositions. Snow cover pollution decreases as follows: yurt districts > industrial zone > multi-storey districts.

State of the environment of urban and mining areas in the Selenga Transboundary River Basin (Mongolia Russia)

The pollution of the soil cover, river water and bottom sediments in the Ulaanbaatar and Ulan-Ude cities and the Erdenet and Zakamensk mining centers was assessed using the data of geochemical surveys in 2011–2015. In Ulaanbaatar, the highest pollution with Pb, Cd, Zn, Mo, Cr, and Cu is revealed in the central industrial–transport–residential area. Emissions from thermal power plants and motor vehicles are the main sources of pollutants. In Ulan-Ude, the highest concentrations of Pb, Cd, Sb, and Sn are observed in the soils of the industrial zone with various engineering and manufacturing enterprises. The topsoils in the mining centers are contaminated with ore and accompanied elements: Mo, Cu, As, Sb in Erdenet, and W and Mo, W, Bi, Cd, Pb, and Sb in Zakamensk. The extremely hazardous level of the soil pollution in Erdenet was revealed in the mining complex area, while in Zakamensk, it occupies about half of the city’s territory. The Ulaanbaatar city’s effect on the trace element composition of water and bottom sediments in the Tuul River during the summer floods is insignificant, in low-water season content of dissolved Pb, Cd, Zn, Co, Sr, Ni and Cu, Co, V in suspension increase many times. In the Selenga River lower course near Ulan-Ude, the floodwater has high concentrations of dissolved Cu, Co, V, Ni and is slightly enriched with suspended V, Bi, Sb, Sn, Mo; the concentrations of heavy metals in bottom sediments remain unchanged. The mining centers exert a local impact on the river network.

An ecological-geochemical assessment of the state of woody vegetation in Ulaanbaatar city (Mongolia)

Based on the results of a biogeochemical survey, an assessment of the state of woody vegetation in the functional zones of Ulaanbaatar is given. A strong accumulation of Zn and Cd is detected in poplar leaves, with Mo and V found in larch needles. Among the factors responsible for the accumulation of microelements in poplar leaves, the main ones are the altitude (for As, Cd, Co, Cu, Ni, Zn), city sector (V, Pb), functional zone (Cr, Sr), and composition of soils and rocks (Mo). The microelements with a high (Pb, V) and low range (As, Cd, Co, Cr, Ni, Sr, Zn) of atmospheric transfer are revealed. Poplar trees are tolerant to pollution, while larch trees suffer a significant deterioration in vital functions under urban conditions.

Long-term dynamics of anthropogenic solonetzicity in soils of the Eastern okrug of Moscow under the impact of deicing salts

The long-term dynamics of the anthropogenic soil solonetzicity under the impact of applied deicing salts were studied in the Eastern administrative okrug (EAO) of Moscow. The composition and amount of the applied agents and distribution patterns of sodium in snowmelt water and in soils of different land-use zones were analyzed. The maps of soil solonetzization in the EAO in 1989, 2005, and 2010 were compiled, and the degree of degradation of the soil cover was evaluated. It was shown that the contrast of the technogenic anomalies in the content of exchangeable sodium and the size of these anomalies in soils of the okrug increase with time. In 21 years, the mean content of exchangeable sodium in the surface soil layer increased from 0.38 to 0.80 cmol(equiv.)/kg, and the degree of solonetzicity (as judged from the exchangeable sodium percentage) increased from 3.1 to 7.2%. In 2005–2010, the rates of sodium accumulation in the soil adsorption complex were twice as high as those in 1989–2005.