Identification of the state of the soil-plant systems on the RUDN-University campus

What is it about?

The results of the analysis of thermodynamic characteristics of the processes of hydrocarbon amassment in the components of geochemical systems are presented (waters, soils, plants and other substances forming ecosystem). The need to use an ideology and apparatus for calculating thermodynamics is due to the complexity and diversity of mass transfer in interacting media. The material and energy flows of marker compounds, polycyclic aromatic hydrocarbons (PAHs), are analyzed: Naphthalene (Naph), Acenaphthene (Ace), Fluorene (Flourene), Phenanthrene (Phen), Anthracene (An), Fluoranthene (Flu), Pyrene (Py), benzo[a]anthracene (BaA), Chrysene (Chr), Benzo[b]fluoranthene (BbFlu), Benzo[k]fluoranthene (BkFlu), Benzo[a]pyrene (BaP), Benzo[ghi]perylene (Bghi), Dibenzo[a,h]anthracene (DbA), Indeno[1,2-cd]pyrene (Ip). Estimates are obtained of the intensity of PAH concentration processes in geochemical systems in different states from the point of view of stability, from clearly unstable to metastable. The role of living matter in the formation of stability of geochemical systems is revealed

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Photo by Sam Jotham Sutharson on Unsplash

Photo by Sam Jotham Sutharson on Unsplash

Why is it important?

The proposed study focuses on PAHs – very common in the environment, persistent substances able to cause significant negative effects on organisms. At the same time, an important feature of this group of substances is the ability to mark natural and technogenic processes. Analysis of PAH concentrations reflects the hydrocarbon flows in the environment, allows to identify areas of influence of pollution processes. The specific structure of molecules (2 and more benzene rings) determines the hydrophobicity and lipophilicity of molecules and their behaviour in media. Ordering the movement of organic molecules dissolved in water solutions in the gravitational field creates conditions for their collective behaviour. Coherent motion occurs even in systems that are "sensitive" to weak fluctuations in the gravitational field. This is the reason for the difference in the concentration gradients of hydrocarbons and, as a result, the variation processes in geochemical systems (GCS), acting from outside, and the development of the system itself, depending on the receipt of energy quanta. According to Buck et al. (1987), systems with a large number of interacting elements naturally evolve to a critical state in which any (even small) event will lead to the destruction of the system or a change of state. This principle is the base of our research on the concentration of PAHs through estimates of measures of heterogeneity (entropy) in GCS is based on. Other thermodynamic characteristics have been also calculated for assessing the direction of processes: changes in Gibbs energy (ΔG) and enthalpy (ΔH). The distribution of substances in octanol and water (log Kow) for PAHs was also used, which allows to judge the selective possibility of their movement with solutions in media

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