Identification of spatial patterns, geochemical associations and assessment of origin-specific health risk of potentially toxic elements in soils of Armavir region, Armenia.

The study of soil potentially toxic elements (PTE) contents and establishment of the geochemical characterization of areas which have never been studied is of great concern. In 2019, soil survey of the Armavir region (Armenia) was conducted in order to investigate the spatial pattern of PTE, reveal PTE geochemical associations and assess the origin-specific health risks. The application of compositional data analysis and geospatial mapping allowed to identify two clusters of samples. The first cluster was spatially located on volcanic rocks and was represented by Fe, Co, Mn, Ti, Zn, Ba, Pb suggesting a natural origin of PTE in these areas. The second cluster was allocated on the alluvial, deluvial, and proluvial sediments and represented by As, Cu, Cr, Ni. Such combination of elements in the same group indicates the anthropogenic introduction of some quantities of PTE. The latter is confirmed by the presence of outliers and extreme values for As, Cu and Ni, as well as by the spatial colocation of Fe, Mn, Co, Pb, Zn outliers and extreme contents. The health risk assessment showed that for children the multi-elemental non-carcinogenic risk was detected, while for the adults the non-carcinogenic risk and carcinogenic risk were below the allowable level. The detailed study of the risk levels showed that in first cluster comparatively higher risk were observed for Pb, V, Ba, Zn while in the second cluster: Fe, Co, Mn, As, Cr, Cu, Ni. The results indicated the necessity of additional in-depth studies with special focus on bioavailability of PTE.