Pollutants and chemical markers of anthropogenic pressure in urban areas: a cross-analysis of soil and Betula pendula roth bark
A. S. Olkova1, O. E. Kononova1,2, D. V. Chuprakov1
1Vyatka State University, Kirov, Russia
2N. V. Rudnitsky Federal Agrarian Scientific Center of the North-East, Kirov, Russia
Keywords: urban ecosystem, pollution, atomic emission analysis, mass spectral analysis, soil, tree bark, enrichment coefficient, cluster analysis
Abstract
The present work investigates the correlations between the concentrations of 40 chemical elements in soil (0-5(7) cm) and in Betula pendula Roth bark. Samples were collected in transport and recreational areas of Kirov city, Russia (taiga zone, temperate continental climate). Pollution indices (PI) were calculated by comparing the element content in the upper continental crust with that in the soil samples. The following series of elements with PI > 1 were established: Ag (4.91) > Cd (3.44) > Pb (3.16) > Sb (3.38) > Zn (2.19) > Ni (2.14) > Cu (1.69) > As (1.16) for recreational areas and Ag (2.97) > Cd (2.87) > Sb (2.11) > Cu (1.34) > Zn (1.28) > Pb (1.09) for transport areas. Birch bark accumulated most of these elements (PI>10): Zn, Cd, Ag, Cu, Sb, Pb, Ni, Hg, Mn, Mo, Sn, Bi, Cr. Cluster analysis was applied to the data. Soil elements were divided into two groups: metals associated with anthropogenic activity and rare earth/noble metals, which are not typical of urban environments. A strong correlation was shown between some biogenic elements and potentially toxic metals Na and Zn (r = 0.68), P and Cd (r = 0.98), P and Pb (r = 0.99), Ca and Tl, Cu, Ni (r = 0.95 to 0.998). Thus, Ag, Cd, Pb, Sb, Zn, Cu, Ni, As were classified as pollutants that accumulate in the soil for a long time and may migrate to plants. Indicators of recent anthropogenic pressure include Hg, Mn, Mo, Sn, Bi, and Cr. Further monitoring should focus on Sc, V, Co, Zr, Ba, Hf, Ga, Rb, Ta, Be, Tl, Nb, Li, and Cs, as their concentrations correlate with both biogenic elements and pollutants.
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