Anisotropy of the polyarenes distribution in the urban soil-plant systems under the conditions of transport pollution

The interaction of natural structures (urban ecosystems) and anthropogenic pollution flows caused by transport pressure is chaotic; this fosters anisotropy of the geochemical system properties. Detailed local models facilitate investigation of these processes. The research object is the RUDN University campus (Moscow) with the adjacent park zone. The flows of marker compounds (polycyclic aromatic hydrocarbons, PAHs) were evaluated for the soil–plant roots–stems system. The status of soil-plant systems in functional zones of the studied area was characterized in detail, and the differences between accumulation and exchange of pollutants were demonstrated. Assessment of the anisotropy is based on translocation coefficients and the entropy increment of pollutants along the selected profiles through the conditionally background zone and through the highway. PAHs flows in the soil–roots and roots–stems subsystems are largely inconsistent. The study sheds light on a significant buffer role of the root system in the redistribution of PAHs flows from the soil, as well as the selectivity of migration depending on the PAHs molecular weights. The quasi-equilibrium modes of interacting elements of the soil-plant system are typified, and various types of periodic modes are identified. Such models are necessary to determine the status of the soil and plant systems of the city and optimize the transport load. [Display omitted] •Transport pressure forms irregular spatial distribution of pollutants in urban ecosystems.•Stochastic mode of urban ecosystems pollution is due to the wave nature of the transport impact.•PAHs transition factors in soil-plant system justify a wave mode of pollution.•Anisotropy of pollution is estimated based on the spatial change of PAHs entropy.•Detailed impact models are most efficient in studying the pollution anisotropy.