Factors conditioning the content of chemical elements in soil and mosses in Armenia

Abstract

In this research, chemical element contents were determined using the Epithermal neutron activation analysis (Cr, V, Ti, Sr, Rb, As, Zn, Co, Fe, Mn and Ba) and atomic-absorption spectrometry (Cu and Pb) for mosses and X-ray fluorescence spectroscopy (Cr, V, Ti, Sr, Rb, As, Zn, Cu, Co, Fe, Mn, Pb, and Ba) for soil samples. The research team combined compositional data analysis and geospatial mapping to reveal key factors conditioning moss and soil chemical composition. The results showed that significant correlation was detected between Cr, Sr, Rb, As, and Pb for Syntrichia ruralis moss and soil contents suggesting their origin stemming from soil resuspension. Meanwhile, in the case of pleurocarpus (Homalothecium philippeanum) moss species, the mechanisms conditioning the transfer of elements to mosses from dead or living plant materials were found to be responsible for mosses Zn, Sr, Mn, Rb, As, Ba, Cu contents. Both media were identified to display multivariate outliers in the same sampling sites which were characterized by the presence of natural mineralization and mining and smelting activities. The compositional PCA and k-means clustering show that the soil element content groupings are in line with the geological base, whereas in the case of mosses, the rural and urban gradient plays a pivotal role in the spatial separation of the identified clusters. In addition, moss samples included in a cluster representing the urban areas of the country have included typical anthropogenic elements (Pb, Cu, Zn etc.) confirming the applicability of the studied mosses in pollution source identification.