Extreme flooding in May, 2014 affected the sub-catchments of six major rivers in Serbia. The goal of the study was to evaluate the contents of potentially toxic elements (PTEs) As, Cd, Pb, Cr, Ni, Cu, and Zn in flood sediments and arable soils within the affected sub-catchments using regulatory guidelines and background levels. The sub-catchment of West Morava was selected to assess the degree of sediments and soils contamination and environmental risk [using the Pollution index (Pi), Enrichment factor, Geo-accumulation index, and Potential ecological risk index (PERI)] as well as to identify main PTEs sources by Principal component (PCA) and cluster analysis. Contents of Ni, Cr, As, Pb, and Cu above both guidelines and background levels, and of Zn and Cd above background levels were detected in the sediments and soils from all the sub-catchments. Pi indicted that about 95% of the soils and sediments were extremely polluted by Ni and about 65% slightly polluted by Cr, whereas about 90% were not polluted by As, Cd, Pb, Cu, or Zn. Ef indicated minor to moderate enrichment of the soils and sediments by Ni, and Cr. PCA differentiated a geogenic origin of Ni, Cr, As, and Pb, a mixed origin of Cd and Zn, and a predominantly anthropogenic origin of Cu. PERI of the soils and sediments suggested a low overall multi-element ecological risk. The ecological risk of the individual elements (E r i ) for soils was Zn < Cr < Pb < Ni < Cu < As < Cd.
Keywords: Diffuse sources; Floodplains; Geogenic sources; Pollution indices; Sediment; Trace elements.