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Geochemical and mineralogical dispersion in the upper Sava River (Slovenia), a preliminary report

1. INTRODUCTION Sava River is formed from Sava Dolinka and Sava Bohinjka. It has a large drainage area. It flows throughout Slovenia, Croatia, at the border of Bosnia and Croatia, and at Belgrade (in Serbia) enters the Danube River. ŠTERN & FÖRSTNER (1976) have been the first to describe heavy metals distribution in the sediments of the Sava Basin in Slovenia. Quality of water in Sava River is regularly controlled within National monitoring programs which do not include systematic measurements of sediments. The aim of our work was to study the impact of tributaries on mineralogical and elemental composition of sediments from main stream Sava, starting from mostly clean environments in north-west Slovenia, down below the inflow of Kupa River at Sisak in Croatia, where anthropogenic influence could be expected. 2. SAMPLING AND METHODS In Fig. 1 are presented sampling locations (between 46o05' and 46o30' N and between 13o45' and 15o10' E), which have been studied till now. Sediments were taken in contact with running water on several occasions in years 2001 and 2002. The lowest point studied was above the inflow of Savinja River, for which we have found that anthropogenic pollution is significant (FRANČIŠKOVIĆ-BILINSKI et al., 2002). Samples were sieved and dried at 80oC. All analyses were performed on silt+clay fraction (<63 ľm). Mineralogical composition was determined using XR diffraction (Philips PW 1050). Elemental composition was determined in Actlabs, Canada, by ICP-MS (Ultratrace 2) and by Flow-injection for Hg (1G) programs. A principle component analysis (PCA) was performed on multivariate data, in order to extract the main elemental asso-ciations, which control the multivariate signature of data base in the upper drainage area. 3. RESULTS From XRD analysis could be concluded that sediment at the source of Sava Dolinka (No.74) contains dolomite as principle mineral component, while in Sava Bohinjka (No.42) calcite predominates. Sediment of Sava Dolinka (No.70) taken before the confluence of the two rivers shows the predominance of quartz. It can be assumed that it comes by several streams flowing from Karavanke, which have not yet been analyzed. Tržaška Bistrica (No.69), which also flows from Karavanke, and Sora (No.65 and 64) have sediments composed predominantly of quartz and mica minerals. Kamniška Bistrica (No.67), which flows from Kamniško-Savinjske Alps has sediments composed predominantly of dolomite. Sediment of Sava River further downstream contain quartz as principle component. From elemental analysis follows that the most abundant elements are Ca, Mg, Fe and Al. They are present in different proportions, depending on sample location. Increased concentrations of most trace elements were found in Sava Dolinka (No.70 - Camp Šobec), probably originating from iron industry in Jesenice. A principle component analysis (PCA) was performed on multivariate data. The main elemental associations can be discussed in details in connection with 3 PCA components. The geochemical data can be interpreted as a weathering of different source rocks during which trace elements are dissipated in the downstream direction. It is also possible to identify pollution sources in the lower region of investigated area. 4. CONCLUSION At this stage of research conclusions are only preliminary. Upper part of Sava drainage basin was selected as a clean environment, slowly changing downstream, where anhtropogenic influence could be observed with highest concentrations of trace elements in sediments of Sava Dolinka in Camp Šobec. It is situated about 10 km downstream from iron industry in Jesenice. Mineralogical composition changes due to tributaries and at the lower part of investigated area is quartz predominating. A principle component analysis (PCA) was performed on multivariate data in order to extract the main elemental associations, which control the multivariate signature of database. Further research will be extended on influence of Savinja, Krka and Kupa tributaries, where anthropogenic influence is assumed and where Mössbauer spectroscopy could also be applied. ACKNOWLEDGEMENTS Research was funded by the Ministry of Science and Technology of Croatia, project 0098041, bilateral project Slovenia-Croatia (2000-2002) and JF-169, USA-Croatia. REFERENCES: FRANČIŠKOVIĆ-BILINSKI, S. ; BILINSKI, H. ; TIBLJAŠ, D. ; HANŽEL, D. & MERTELJ, A. (2002): Characterization of sediments from Voglajna and Savinja rivers - preliminary results. Geologija 25/2, 367-372. ŠTERN, J. & FÖRSTNER, U. (1976): Heavy metals distribution in the sediment of the Sava Basin in Slovenia. Geologija 19, 259-274.

Sava River; sediments; heavy metals distribution; anthropogenic influence; mineral composition; principle component analysis (PCA)

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