Thermodynamic assessments of the migration and accumulation of PAHs in the soil–plant system

The study is devoted to the thermodynamic modeling of the environmental pollution processes. A research object is an urban area (RUDN University campus with a forest park zone, Moscow, Russia) under high-level traffic pressure. Based on the thermodynamic characteristics of the flows of marker compounds (14 polyarenes from the EPA list, measured in soils, roots, and aerial parts of plants), a model of the response of the soil–plant system was developed. The entropy increments and the values of the cumulation coefficients for the soil–plant system are informative indicators of the intensity of anthropogenic loads. It was shown that formation of zones of entropy minima and PAH concentration maxima in soils are caused by a combination of transport activity and soil self-purification processes. The difference in the conditions of technogenic pressure in the functional zones of the considered territory, the preservation of the ability of soils to self-purify, and the ability of plants to regulate PAH flows are most clearly demonstrated with the use of indicators of changes in the entropy of PAH associations.