engleski

Characterization of sediments from Voglajna and Savinja rivers

Preliminary studies of surface sediments (f < 63 ľm) from Voglajna and Savinja rivers are reported and discussed. XRD data showed that river sediments predominantly consist of quartz. Muscovite was found in all samples as minor mineral. Feldspars were detected in sediments of Voglajna. Calcite was found in Voglajna near Šentjur and Štore. Calcite and dolomite were found in sediments of Savinja. From about 50 elements determined by ICP-MS method, concentration of iron predominates (2.8-5.6%). It is highest in Voglajna at Štore. From microelements the highest concentrations of Cr, Ni, Cu, Mo, Sb, W and Pb were found in the same sediment. Concentration of Al and K are similar in all samples. Ca and Mg are higher in Savinja, than in Voglajna. Zn, Cd, Ag and Au show the highest concentrations in sediments of Savinja at Tremerje, below Celje. Most of trace elements are in good correlation with iron. Iron minerals could not be well determined by XRD. Further characterization of iron in sediments was performed by 57Fe Mössbauer spectroscopy at room temperature. Spectra were fitted with two doublets showing relatively similar isomer shifts and quadrupole parameters. The ratio Fe(III)/Fe(II) decreases downstream Voglajna river. In addition to the presence of two doublets, two magnetic sextets are present in the sediment of Voglajna at Štore, suggesting the presence of Fe3O4 in minor quantity. The work is in progress to determine iron containing minerals in these rivers.

sediments; Voglajna and Savinja rivers; XRD; ICP-MS; trace elements; Mössbauer spectroscopy; iron minerals

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