D. N. Gabov

Formation of polycyclic aromatic hydrocarbons in northern and middle taiga soils

An integrated study of the qualitative and quantitative composition of polycyclic aromatic hydrocarbons (PAHs) in the atmospheric precipitation-soil-lysimetric water system was performed using high performance liquid chromatography. It was shown that the accumulation of low-molecular PAHs (phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, and chrysene) in soils is due to the transformation of organic matter and the regional transport and deposition of PAHs with atmospheric precipitation on the underlying surface. High-molecular polyarenes (benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benzo[ghi]perylene, and indeno[1,2,3-cd]pyrene) mainly result from the decomposition of soil organic matter.

Polycyclic aromatic hydrocarbons in soils of Vasilievsky Island (St. Petersburg)

The composition and accumulation patterns of priority polycyclic aromatic hydrocarbons (PAHs) in soils of Vasilievsky Island in Saint Petersburg were studied. Concentrations of benzo[a]pyrene were found to exceed maximum permissible concentrations in all the samples, and the maximum recorded concentration exceeded the MPC by 50 times. Concentrations of other PAHs also exceeded the background values. The main soil pollutants were found to be fluoranthene, pyrene, benzo[b]fluoranthene, benzo[a]pyrene, and benzo[g, h, i] perylene, the part of which in the total content of PAHs was 65–80%.

Bioaccumulation of polycyclic aromatic hydrocarbons in the soil-plant systems of the northern-taiga biocenoses

Regularities in the formation of the pool of priority polycyclic aromatic hydrocarbons (PAHs) in the soil-plant systems of the northern taiga forest biocenoses were revealed. In soils and plants, PAHs mainly consisted of 3- and 4-nuclear structures. The content of polyarenes in plants on technogenically contaminated areas exceeded the background values by 2–5 times. The maximum bioconsumption of polyarenes was observed for bilberry leaves and Siberian spruce sprouts 4–5 years old. The highest mass fraction of PAHs was found in Siberian spruce plants of a mixed spruce-birch forest of the northern taiga. It was revealed that bilberry plants are hyperaccumulators of light PAHs.

Saturated hydrocarbons in the background and contaminated soils of the cisurals

A homologous series of n-alkanes (C20–C35) was identified in peaty-podzolic-gleyic soils. Structures with odd numbers of carbon atoms (C25–C35) were predominant in the soil organic matter. It was found that the major amount of both odd and even n-alkanes was accumulated in the peaty litter. In the mineral horizons, the mass fraction of the odd n-alkanes abruptly decreased to become comparable to that of the even n-alkanes in the soil-forming rock.

Polycyclic aromatic hydrocarbons in tundra soils of the Komi Republic

The qualitative and quantitative composition of polycyclic aromatic hydrocarbons (PAHs) in tundra soils has been studied by gradient high-performance liquid chromatography. The differentiation of the PAHs in the soil profile is of clear accumulative character. The pool of polyarenes in the soils is determined by the cryogenesis processes and mainly consists of low-molecular-weight bi- to tetranuclear PAHs, the high-molecular-weight PAHs in the organic horizons make up no more than 20% of the total polyarenes in the soil, and penta- and hexanuclear structures are almost absent in the mineral layer.

Properties of soils and soil-like bodies in the Vorkuta area

The specific features of the formation of soils and soil-like bodies on technogenic substrates in Vorkuta—a polar city specializing in coal mining—are characterized. According to the new Russian soil classification system, these soils are classified as urbanozems (urban soils) and constructozems (soil-like bodies constructed by humans); the latter are subdivided into recreazems (soil-like bodies of recreation zones) and replantozems (soil-like bodies of reclaimed urban areas with planted vegetation). They are characterized by the increased content of heavy metals and by some alkalization of the upper soil horizons in comparison with the natural background soils. The benz(a)pyrene content in most of the soil samples exceeds the maximum permissible concentration (MPC). The maximum levels of the soil contamination with benz(a)pyrene reach 80 MPCs. According to the total contamination index calculated relative to the background concentrations of the major contaminants, the upper horizons of the investigated soils and soil-like bodies are qualified as ecologically hazardous and extremely hazardous bodies.

Pyrogenic changes in iron-illuvial podzols in the middle taiga of the Komi Republic

The changes in the morphological, physicochemical, and chemical properties of iron-illuvial podzols under middle-taiga dwarf shrub-green moss pine forests in the first months after fires are examined. It is shown that forest fires are accompanied by changes in the morphology of the litter horizons, their compaction, and by changes in the chemical properties of the soils. The data on the polycyclic aromatic hydrocarbons (PAHs) indicate a significant increase in the contents of chrysene, fluorene, naphthalene, pyrene, and anthracene in the Opyr(L) horizon in comparison with the litters in the background pine forest. The total PAH content in the O(F)pyr horizon increases mainly at the expense of di- and tri-nuclear PAHs (naphthalene and fluorene). The mineral soil horizons in the burnt area become enriched in the most mobile amphiphilic fractions of the organic matter, which is seen from the increase in the absolute and relative contents of the hydrophilic fractions, which might be represented by the products of combustion of fresh plant remains and litter.

Polycyclic aromatic hydrocarbons in the soils of technogenic landscapes

An integrated study of qualitative and quantitative composition of polycyclic aromatic hydrocarbons (PAH) in the atmospheric precipitation-soil-lysimetric water system of aerotechnogenic polluted landscapes was conducted using high-performance liquid chromatography in a gradient mode. Only low-molecular weight polyarenes (phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, and chrysene) were found in the atmospheric precipitation and lysimetric waters. The growth of PAHs in soils is provided by the input of phenanthrene, fluoranthene, and pyrene with atmospheric precipitation. The absence of heavy PAHs (benzfluoranthenes, benz(a)pyrene, dibenz(a,h)anthracene, benz(ghi) perylene, and indeno[1,2,3-cd]pyrene) in the atmospheric precipitation and their identification in soil give grounds to state that their accumulation was caused mainly by transformation of organic matter during pedogenesis. The technogenic impact was estimated and criterion of the degree of soil pollution by PAH was proposed.

Accumulation of polycyclic aromatic hydrocarbons in soils and plants of the tundra zone under the impact of coal-mining industry

Thirteen polycyclic aromatic hydrocarbon (PAH) compounds were identified in organic horizons of tundra surface-gleyed soils ( Histic Stagnosols (Gelistagnic) and plants. The total content of PAHs in contaminated soils exceeded the background values by three times. Concentrations of low-molecular weight hydrocarbons in soils at different distances from the coalmines were relatively stable. Concentrations of highmolecular weight hydrocarbons had a distinct maximum at a distance of about 0.5 km from the source of emission. The increased values of correlation coefficients were found between PAH concentrations in organic soil horizons, plants, and coal of the Vorkutinskaya mine. Mostly low-molecular weight structures predominated in the organic soil horizons and in the studied plant species. The maximum capacity for the biological accumulation of PAHs was displayed by Pleurozium schreberi and the minimum capacity was displayed by Vaccinium myrtillus. Mosses and lichens actively absorbed polyarenes from the surface; most of the PAHs were transported into the plants. This phenomenon was not observed for Vaccinium myrtillus Concentrations of PAHs on the surface and in plant tissues decreased with an increase in the distance from the mine. Distribution of polyarenes in plant organs was nonuniform. Insignificant excess of concentration of polyarenes was found in dead part of Pleurozium schreberi in comparison with its living part. The accumulation of polyarenes in the leaves of Vaccinium myrtillus was higher than that in its stems and roots.

Polycyclic aromatic hydrocarbons in soils and lower-layer plants of the southern shrub tundra under technogenic conditions

In soils and plants of the southern shrub tundra, 15 polycyclic aromatic hydrocarbons (PAHs) have been detected by high-performance liquid chromatography. Polyarenes in emissions, soil organic horizons, and plants mainly include low-molecular-weight PAHs: naphthalene, fluorine, and pyrene. The contents of the total PAHs in soils and plants exceed the background levels by 3–5 times. The distribution of polyarenes among the organs of the studied plants is nonuniform and depends on the plant species and technogenic load on the area. The studied plants include both hyperaccumulators of polyarenes (Pleurozium schreberi) and indicators of PAHs in the soil (Polytrichum commune). Pleurozium schreberi is the most abundant species in the areas under study, and it accumulates the largest mass fraction of PAHs. The differences in the accumulation of PAHs by the plants of the tundra and taiga zones have been revealed.