Environmental implication indices from elemental characterisations of collocated topsoil and moss samples

Abstract

Pollutants, once emitted into the atmosphere, are deposited on the Earth's surface where they further accumulate in both biota and soil. It is therefore a challenge to assess pollutant distributions in different media, and define the various scaling factors to correctly assess each pollutant's environmental implications. In this study, the concentration of potentially toxic elements and their environmental implications were estimated for moss Hypnum cupressiforme Hedw. and the collocated topsoil (0-5 cm) samples, collected from 21 sites across the Province of Kosovo and Metohija (Serbia) during June 2016. The concentrations of Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, U, V, and Zn were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Median Ba, Cd, Cr, Co, Ni, V and maximum As, Cu, Pb, and Zn concentrations in topsoil samples from the study area were higher than prescribed limits in the national and international regulations. Furthermore, we applied and discussed different metrics to assess the pollution level (enrichment factors [EFs], geo-accumulation [I-geo] and pollution load index [PLI]). Different pollution scaling indicates moderate to severe environmental implications (2 lt PLI lt 5; 1 lt I-geo lt 7, 1 lt EFs lt 275) of the potentially toxic elements in the study area. The sampling sites in the northern part of the study area, well-known for their mineral resources, are particularly affected by toxic element pollution, which is likely a consequence of both the exploitation and waste disposal taking place there. More specifically, a comparison of element EFs calculated according to the Earth's crust values with those considering the topsoil background values, points toward a strong influence of (resuspended) soil component in the element enrichment of all environmental samples (i.e., in both the moss an collocated topsoil). However, the EFs of Pb, Cu, Zn, and U in the moss samples were notably higher than those calculated for the collocated topsoil, which could be an indication of a non-local pollution. Finally, both the collocated measurements and multiscale pollution assessment, performed simultaneously, testify to the strong geochemical 'signature' of the studied area.