The distribution of integral indicators of the soil-plant system components contamination with polycyclic aromatic hydrocarbons in the urban area has been considered. An anthropogenically modified natural complex of the RUDN University campus and the adjacent South-Western Forest Park (Moscow) was the object of study. Soils (Albic Retisols (Ochric)) and common plant species were studied. Traffic load was the main pollution source. Emissions from five sections of roads, around and across the territory, formed a specific pattern of pollutants, which was demonstrated by the example of marker compounds, namely, polycyclic aromatic hydrocarbons. Background concentrations of individual polyarenes in the environment, determined by the method of dynamic phase portraits, have been calculated as an approximate safe level of contamination of soils and vegetation. A local redistribution of contamination zones was revealed owing to the migration of polyarenes from snow into soils, and then into root systems, and the above-ground parts of plants distribution. The proposed methodological approach, based on the use of integral indicators, allows us to assess the degree of damage to ecosystems caused by a complex of priority pollutants.

Kerosene is widely used in various types of anthropogenic activities. Its environmental safety is mainly discussed in the context of aerospace activities. At all stages of its life cycle, aerospace activity impacts the environment. In aviation, the pollution of atmospheric air and terrestrial ecosystems is caused, first of all, by jet fuel and the products of its incomplete combustion and is technologically specified for a number of models in the case of fuel leak during an emergency landing. In the rocket and space activities, jet fuel enters terrestrial ecosystems as a result of fuel spills from engines and fuel tanks at the crash sites of the first stages of launch vehicles. The jet fuel from the second and third stages of launch vehicles does not enter terrestrial ecosystems. The fuel components have been studied in sufficient detail. However, the papers with representative data sets and their statistical processing not only for the kerosene content, but also for the total petroleum hydrocarbons in the soils affected by aerospace activity are almost absent. Nevertheless, the available data and results of mathematical modeling allow us to assert that an acceptable level of hydrocarbons, not exceeding the assimilation potential, enters terrestrial ecosystems during a regular aerospace activity. Thus, the incoming amount of jet fuel disappears rapidly enough without causing any irreversible damage.

The boreal forests of Russia are one of the largest forest areas on the planet. As a result of climate change, the rate of carbon sequestration and stabilization of organic matter are important indicators of environmental conservation. To understand mechanisms of stabilization and the structure of soil organic carbon, the molecular-weight (MW) distribution of humic acids (HAs) in soils of the central deciduous-forest zone of boreal forests (Chernevaya taiga, transitional ecotone forest, coniferous forest) was studied. Analysis of the MW distribution of HAs was conducted using size-exclusion chromatography. This approach allowed us to obtain the distribution of high-, medium-, and low-molecular fractions of HAs. It has been revealed that the content of the low-MW fraction prevails over the content of the medium- and high-MW fractions of HAs, which indicates the process of stabilization in soil organic matter. The accumulation of low-molecular-weight fraction occurs with the aromaticity increase in HAs, which indicates that HAs with a relatively high proportion of aromatic fragments have smaller hydrodynamic radius and a lower MW. It has been statistically substantiated that the low-molecular-weight fraction correlates with the content of aromatic compounds and carboxyl structural fragments of HAs, which indicates the resistance of the soil organic matter of Chernevaya taiga to biodegradation.