Origin identification and potential ecological risk assessment of potentially toxic inorganic elements in the topsoil of the city of Yerevan, Armenia

- Pollution by toxic elements is topical in urban areas, Yerevan is not an exception.
- Topsoils of Yerevan are highly polluted by Pb, Cu, Zn, Ni, Cr, Hg and Mo.
- Geostatistical analyses prove anthropogenic origin of Pb, Cu, Zn, Hg, Cr, Ni, Mo.
- Pb and Hg demonstrate a higher potential ecological risk in the topsoils.

The total concentrations of Ti, Fe, Ba, Mn, Co, V, Pb, Zn, Cu, Ni, Cr, Mo, Hg and As were determined in 1356 topsoil samples collected from the area of the city of Yerevan in order to: (1) determine the spatial distribution peculiarity and the origin of potentially toxic inorganic elements in Yerevan soils; and (2) assess the potential ecological risk of potentially toxic inorganic elements. The spatial distribution features of these elements were illustrated by environmental geochemical mapping. Pollution indexes (PIs) of As, Ti, Mn, Fe, Ba, and Co were between the range of 0.9-1.1, while PI of Cu, Zn, Ni, Cr, V, Hg, Mo (1.5-6.8) and especially Pb (22.9) was higher. Multivariate geostatistical analyses suggested that the concentrations of Pb, Cu, Zn, Hg, Cr, Ni and Mo observed in the topsoil bore the influence of anthropogenic and industrial activities. Moreover, according to the main findings of Principal component analysis (PCA) Pb and Zn have two distinct sources of origin: (1) vehicle emission and social activities (PC2); and (2) industrial activities (PC3). The potential ecological risk was quantitatively estimated for each sampling site and a risk map for the assessment was created. Among the investigated elements, Pb and Hg showed a higher potential ecological risk, than the others.