Characterization of sediments from Voglajna and Savinja rivers - preliminary results

Abstract

Preliminary mineralogical, geochemical and Mossbauer studies of six surface sediments (fraction <63 pm) from Voglajna and Savinja rivers (Slovenia) are reported for the first time. The location was chosen because of two reasons. One was possible pollution due to industry in Celje. Another was presumed high concentration of iron (later found 2.8 - 5.6 %), easily studied by Mossbauer spectroscopy. XRD data showed that quartz is present in all samples. Other minerals are different in different locations. Iron can be present in Fe-chlorite and in montmorillonite, found by XRD as trace minerals. Microelements were determined by ICP-MS method. Sediment of Voglajna near Štore contain the highest concentrations of S, P, Cr, Ni, Pb, Cu, Mo, Sb, W and Hg. Sediment of Savinja at Tremerje contain the highest concentrations of Zn, Cd, Ag and Au. These results indicate industrial pollution around Celje. Further characterization of Fe (II) and Fe (III) was performed by 57Fe Mossbauer spectroscopy at room temperature. Spectra were fitted with two and in one čase with three doublets. In addition to the presence of two doublets, two magnetic sextets are present in the sediment of Voglajna at Štore, suggesting minor quantity of Fe304. The Fe (III) / Fe (II) ratio decreases downstream the Voglajna river. The work is in progress on additional sampling stations.