Possible Sources of Heavy Metals in Urban Soils: Example from Belgrade, Serbia

Abstract

The content of heavy metals over time has been continuously increasing in urban soils as a consequence of industrialisation and often unclear sets of environmental controls and protection procedures. However, the role of geological parent material as a natural source of heavy metals should not be underestimated. Precise determination of the source of heavy metals in urban soils is a crucial element in remediation process. The aim of this study is to determine the concentrations and main sources of heavy metals in the soils of Belgrade, Serbia. For that purpose, concentrations of heavy metals were determined on 180 samples from 38 locations. Results show that in most tested locations Ni and Pb have higher concentration than permitted by legal norms of Serbia or recommended values by the Dutch list. Peridotites and serpentinites underlying Belgrade soils are the main sources of Ni, while high lead concentrations are the consequence of traffic pollution. Correlations of heavy metal contents further prove these findings: Ni is positively correlated with Cu and Cr, elements associated with ultramaffic rocks, and Pb is positively correlated with Zn, which is also typical for traffic pollution. Our work shows that when identifying the source of heavy metals in urban soils both anthropogenic and natural origins should be taken into consideration.