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In the course of the model experiment, extraction conditions of 16 priority PAHs in subcritical water medium were selected for soils of the chestnut-solonetz complex. For low molecular weight 2-ringed naphthalene and 3-ringed acenaphthene, acenaphthylene, anthracene, phenanthrene and fluorene, the optimal extraction conditions correspond to 10 minutes at a temperature of 200°C. For high molecular weight 4- and 5-ring benz(a)anthracene, fluoranthene, pyrene, chrysene, benz(b)fluoranthene, benz(k)fluoranthene, dibenz(a,h)anthracene, as well as the pollutant of the first hazard class - benz(a)pyrene, the optimal extraction time reached 20 minutes at a temperature of 250°C. For 6-ring benz(g,h,i)perylene and indeno(1,2,3-cd)pyrene, the optimum extraction time increased to 30 minutes and the temperature to 300°C. When comparing the methods of extraction of pollutants from soils, it is shown that the extraction methods can be placed in the following descending order by the value of the extraction coefficient of priority PAHs from the studied types of soils: ultrasonic extraction (1.05) > subcritical extraction (1.13) > saponification method (1.25). Using multivariate analysis of dispersion it is shown that the efficiency of subcritical aqueous extraction decreases with increasing number of benzene rings in the PAH molecule, as well as with increasing soil salinity in the following order: Gleyic Kastanozems < Endosalic Kastanozems < Kastanozems Sodic < Solonets. [ABSTRACT FROM AUTHOR]

The main regularities of pollutant distribution through the soil profile were established based on the analysis of the content of 15 priority PAHs in 29 soil sections of different soil types located in the coastal zone of the Lower Don and Taganrog Bay with different anthropogenic loads. It was shown that the total content of PAHs in the 0-20 cm layer of soils of coastal territories varies from 172 μg kg-1 to 16006 μg kg-1. In addition, according to the total pollution indicator, (Zc) determines the level of soil pollution, which varies from "not polluted" to "extremely polluted". The influence of pollution sources falls on the 0-20 cm layer of soils of different types and is especially pronounced for subordinate landscapes. With increasing sampling depth, the total PAH content decreases with the redistribution of individual compounds of the PAH group towards the dominance of low molecular weight and 4-ring compounds in the composition of the sum of 15 PAHs and depends largely on the content of organic matter and soil pH. Based on the cluster analysis results, the main factor determining the profile distribution of PAHs is the type of pollutant origin source and its intensity. [ABSTRACT FROM AUTHOR]

The large-scale studies of the Lower Don and the Taganrog Bay coastal zone were carried out to determine the background concentrations of polycyclic aromatic hydrocarbons (PAHs) in soils. The content of 15 priority PAHs was determined by saponification method with HPLC detection and varied widely from 77 µg kg−1 to 16,017 µg kg−1 with mean and median values of 1040 µg kg−1 and 406 µg kg−1, respectively. PAHs' highest concentration level was observed in the soils of the Don River delta and industrial areas of Taganrog city affected by pyrogenic contamination sources. Background monitoring sites were mostly represented with hydromorphic (Fluvisols Salic and Tidalic Fluvisols) and automorphic (Rendzic Leptosols, Mollic Leptosols) soil types in the study area. The PAHs content in the soils of the background plots did not exceed 600 µg kg−1, with a share of low-molecular-weight PAHs: about 50%. Benzo(a)pyrene content did not exceed the maximum permissible concentration (20 µg kg−1), and low-molecular-weight compounds did not exceed the threshold level for the impact of polyarenes. In automorphic soils, naphthalene and phenanthrene (35–54%) dominated in the composition of the low-molecular-weight PAHs compounds, and only phenanthrene (59–70%) dominated in hydromorphic soils. [ABSTRACT FROM AUTHOR]

The PAHs transformation in the soils of the coal mining enterprises impact zones and thermal power plants remains poorly studied. In turn, coal mining can be considered as a primary cycle in the production of electricity. One of the main sources of negative environmental impact is the coal mining industry located on the territory of the upland in the south of the East European Plain. The features of PAHs accumulation in the soils of fuel and energy enterprises have been studied on the example of mines impact zones with different service life and the current coal-fired power plant. It was established that, regardless of the period and intensity of the emission source, as well as its current status, the polycyclic aromatic hydrocarbons (PAHs) content in the soils of the impact zones was significantly higher than in the soils of the background territory. The content of low molecular and high molecular weight PAHs in the impact zones soils differed depending on the land use type, as well as the period and intensity of an industrial effect type. The pollutants content of in the soils of all considered impact zones significantly exceeded the background values and according to the low molecular weight PAHs content in the soils, they formed the following decreasing series: Mayskiy ≥ Ayutinsky > Novoshahtinsk > Power station > Background. According the high molecular weight PAHs content, the series changed to: Novoshahtinsk >Mayskiy ≥ Ayutinsky > Power station > Background. Soil pollution markers for enterprises of the fuel and energy complex were identified as pyrene and chrysene, which are part of coal, formed from the hydrocarbon sources. The influence of the power plant was accompanied by the benzo(g,h,i)perylene concentration increase. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the polycyclic aromatic hydrocarbon (PAH) levels in urban topsoils (0–10 cm) affected by Combined Heat and Power (CHP) plant and oil refinery (Antipinsky Refinery) in comparison with residential area topsoils of Tyumen city. Anthropogenically transformed soils (Urbic Technosols) and artificial loamy soils enriched with organic matter with high pH values are widely represented in the residential area and industrial areas. The 12 priority PAHs in soils were analyzed by HPLC method with fluorescence detection. Urban topsoils of residential area have been contaminated mainly by benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, and benzo[g,h,i]perylene whereas enhanced concentrations of fluorene, phenanthrene, benzo[a]anthracene, and benzo[k]fluoranthene were observed in topsoil of industrial areas. The total amount of PAHs in the background soil was 113.5 μg kg−1. The PAH group composition in all studied soils was expressed mainly by high-molecular polyarenes. The maximum accumulation was found for phenanthrene, pyrene, and fluoranthene. The total amount of PAHs in urban soils exceeded the background level up to three times (341.0 μg kg−1). In the residential area, the total PAH content was twice higher than in the industrial areas of CHP-2 plant and the Antipinsky Refinery (482.7, 275.0, and 273.3 μg kg−1, respectively). The PAH content improvement connected with the soil properties, and it was also affected by long-term and intensive anthropogenic impact. It was found that the level of soil pollution in the residential area is typified as hazardous, in the impact area as moderately hazardous, and in the CHP-2 plant impact area, as permissible. [ABSTRACT FROM AUTHOR]

The assessment of toxic effects of polycyclic aromatic hydrocarbons (PAHs) on Haplic chernozems soil was developed by using spring barley (Hordeum sativum distichum) bioaccumulation tendencies. Spring barley was used to estimate the negative effect of chernozemic soil contamination with benzo[a]pyrene (BaP), one the most carcinogenic and mutagenic PAHs compounds. The bioaccumulation tendencies were studied in soil spiking with BaP. Spiked doses were close to technogenic pressure level in studied area, 0–800 µg/kg of BaP. Condition and doses of BaP during 4 years of model experiment influenced morphometric characteristics of spring barley and rates of BaP uptake by plants. Exposure to the growth characteristics containing at least 20 µg/kg BaP promoted absorbing BaP by plants root system as well as increased roots length. Tendencies of phytotoxicity parameters inhibition were observed for all morphometric characteristics of spring barley as energy of germination, length of vegetation part, plant weight and ear height. Quantifiable levels of BaP uptake by spring barley roots exceeded vegetative part more than 2.5 times in all polluted variants. The constant of BaP semi-degradation in artificially polluted Haplic chernozems for 48 months of model experiment T50 reached 1.2–3.4 years. Thus, the BaP uptake by spring barley from chernozem soil contributes to the bioindication responses during environmental monitoring to assess the impact of BaP pollution. [ABSTRACT FROM AUTHOR]