engleski

Characterization of sediments from some flysch rivers of Croatia and Slovenia

Present investigations are a part of the joint bilateral project between Croatia and Slovenia on multidisciplinary research of river sediments formed on different geological settings. Reka was chosen as a flysch river, which sinks into the Škocjan Cave system, proclaimed by UNESCO as a World Heritage site in 1986. According to Brilley and Šraj, thirty years ago Reka was considered as one of the most polluted rivers. Reka river quality is monitored within project IGCP 299 in 1993. Research on the Reka river was continued to 2000 in connections with IHP UNESCO. In the present work, detailed mineralogical and geochemical studies will be performed on surface sediments of fraction <63 ľm. Mössbauer spectroscopy will be used to characterize poorly crystalline iron minerals. From experimental data performed on sediments it can be concluded which elements and which minerals are transported downstream. Results on sediments from Reka river will be compared with those of other flysch rivers, such as Dragonja, Rižana, Raša, Mirna and Rječina rivers, which present important water resources. Quality of water is continuously monitored in both countries. In Croatia monitoring is performed by "Hrvatske Vode". Multielemental analysis of sediments and determination of Fe(III) / Fe(II) ratio by Mössbauer spectroscopy present complementary research to previous works and have not been done before in this region, although useful information about quality of particular rivers can be obtained. Similar approach we used in other locations, while studying Voglajna and Savinja rivers (Slovenia) and Öre estuary (Sweden), see Frančišković-Bilinski et al., 2002 ; 2003. REFERENCES Frančišković-Bilinski, S., Bilinski, H., Tibljaš, D., Hanžel, D. and Mertelj, A. (2002): Characterization of sediments from Voglajna and Savinja rivers - preliminary research. Geologija 45/2, 367-372, Ljubljana. Frančišković-Bilinski, S., Bilinski, H., Tibljaš, D. and Hanžel, D. (2003): Estuarine sediments from boreal region - an indication of weathering. Croatica Chemica Acta 76/2, in press, Zagreb.

Reka; flysch river; Škocjan Cave; Mössbauer spectroscopy; Fe(III) / Fe(II) ratio

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