Selected metal content and binding behaviour in riverbed sediments of the Kavala–Philippi area (Northern Greece)

Abstract

The broader Philippi area (NE Macedonia, Northern Greece), which was chosen for the present study, is characterized by the presence of various metals. An approach to the correlation of selected parameters (grain-size distribution, Al2 O3, CaO, Fe2 O3, MnO, SiO2 content, environmentally available concentrations of Cu and Zn) was carried out in samples collected downstream of Palea Kavala River and Kryoneri and Philippi streams. The abundance of Cu, Fe, Mn, and Zn in relation to four binding fractions (exchangeable, bound to carbonates, Fe–Mn oxides, organic matter complexes) was also investigated. The enrichment of the studied metals was determined by evaluating the enrichment factor (EF) and geo-accumulation index (Igeo). Considering the results, Si was the most abundant major element oxide in sediments, followed by Al, Ca, Fe, and Mn. The sediments are dominated by sand and reveal minor Cu and Fe enrichment and moderate Mn and Zn enrichment. Statistical analyses revealed a significant correlation between Cu, Fe, Mn, and Zn, suggesting their common sources. They probably originate naturally, since the weathering of metal assemblages occurring in the broader Philippi area, comprising minerals such as chalcopyrite, pyrite, goethite, pyrolusite and sphalerite, may contribute to the concentrations of these elements in the sediments.