DETECTION OF GEOCHEMICAL ANOMALIES IN STREAM SEDIMENTS OF THE UPPER SAVA RIVER DRAINAGE BASIN (SLOVENIA, CROATIA)

摘要

Sava River is a transboundary river of supra-regional interest, draining 95,719 km~2 in Slovenia, Croatia, Bosnia and Herzegovina, and Serbia. It is a typical Alpine river, flowing from Julian Alps. On entering Croatia, it becomes a typical lowland river. The possible influence of sediments of the sub-basins of Savinja, Krka and Kupa rivers on the sediments of the main course of Sava River was studied. Mineralogical composition was determined by X-ray diffraction (XRD), and chemical composition by inductively coupled plasma mass spectroscopy (ICP-MS). Two different procedures to identify anomalous geochemical data, the box plot method and the median absolute deviation (MAD), were used. Results obtained by the box plot method showed that anomalous concentrations (extremes or outliers) of Zn, Pb, In, Cu, Co, Se, Zr, Cd, As, K, Na, Tl, Ba, B, Mn, and Fe are present in sediments of the Celje region, as well as of Cr, Ni, S, In, Cu, Mo, Pb in Moste dam (pollution traced down to Camping Sobec), and of Hg in Litija-Zagorje mining region. The MAD method is more sensitive, and depicts the same polluted areas, but with more anomalous values, which are above threshold values for toxicity.