*2.1. Soil Sampling*

Model laboratory experiments with urban ecosystem soils characterized by polyelement anomalies [17] were performed. To carry out the experiments, the soils were collected in the following sites: the sanitary protection zones (SPZ) of large metallurgical enterprises: Kosogorsky Metallurgical Plant (KMP), Tulachermet PJSC (TCh), the embankment opposite the arms and machine-building plants (Embankment), as well as a major highway and a sanitary protection zone of the central avenue of the city (Lenin Ave.). The gray forest soils of the state museum–estate of Leo N. Tolstoy "Yasnaya Polyana" served as background (Background). Sampling and soil preparation for determination of toxic elements was carried out in accordance with RNS R 53123-2008 [31]. The sampling depth was 0–25 cm.
