The article presents an assessment of roadside soil and plant pollution by motor vehicles in the Arctic zone of Western Siberia. The studies were conducted on the Surgut-Salekhard highway near Novy Urengoy and on one of the winter roads south of the town of Tazovsky. A detailed geochemical characteristic of the parent rocks and soils in the study areas is provided. Chemical pollution was mild, since northern roads usually have low to medium traffic intensity.
Statistical modeling based on the consistent application of factor and discriminant analyses of multivariate statistics was used to detect and identify pollutants and the pollution level. It has been shown that the Cd–Pb–Zn–Cu–Ni association in soils indicates the motor vehicles pollution. An additional source of impact in the urban area was residential construction through the Ca–Mn–Co–Sr–Zn association. Similar parageneses have been identified in the study of the solid phase of snow collected at the soil sampling sites, indicating the decisive role of aerotechnogenic transfer of metals in pollution of natural and urban environments. Low activity of lateral and radial migration of metals has been shown even in an acidic medium, attributed to the widespread peat horizon that functions as a compound geochemical barrier: alkaline, biogeochemical, and sorptive. A change in the chemical composition of indicator plant species has been established, caused largely by aerotechnogenic transfer of metals coming from motor transport and road surfaces. Soil pollution within the former winter road and in roadside landscapes has been found to be local. However, there were traces of disturbed soil cover, and soil thawing and an increase in the seasonally thawed layer thickness have been established. In general, chemical pollution caused by the impact of motor transport was not pronounced, and the content of the studied metals was below the standards established for soils (MPC and TPC). Calculation of the toxicity probability index (MERMQ) for contaminated soils showed low to moderate risk levels.
[Methodology: p. 4: ] "A total of 60 samples were collected from different genetic horizons along the Surgut–Novy Urengoy–Salekhard route (including the city of Novy Urengoy), and 61 samples were collected along the winter road. Along with soil sampling, samples of indicator plant species were taken: 19 samples of wild rosemary Ledum decumbens (Ait.) Lodd. ex Steud. and 16 samples of lichen Cladonia stellaris (L.) Rabh. The representativeness of the material selection was ensured by obtaining an average sample of the above-ground vegetation (10–25 plants) from sampling plots 20 × 25 m in size."
[Results: p. 9: ] "The condition of indicator plant species is one of the elements used to assess the impact of motor vehicles on roadside landscapes. For this reason, a study was conducted to determine the chemical composition of plants in the western and eastern sections of the motorway. When compared with background metal contents in Cladonia stellaris and Ledum decumbens [4, 12], it was found that concentrations in lichens in the western section were lower than background levels, while in the eastern section they were higher. In wild rosemary, the content of Na, K, Ca, V, Cr, Ni, Cu, Cd, and Pb in both sections is below background values.
A comparison of the mean metal content in plants using the t-test for two independent samples (eastern and western sections) showed that in the eastern section, Cladonia stellaris had a statistically significant excess of Ca, Sc, V, Cr, Fe, Co, Ni, Cu, and Ba; and in Ledum decumbens it was Sc, V, Fe, Co, Cu, Zn, and Ba (Fig. 5). At the same time, higher concentrations of K and Mn were observed in wild rosemary in the western area."
Keywords: soils, parent rocks, discriminant analysis, geochemical associativity, indicator plant species.
