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Geochemical composition of soils and underlying sediments in the Kremna Basin was investigated. The aim was to assess whether observed heavy metal concentrations in soil samples represent geogenic or anthropogenic contamination. The second objective is to show that geochemical data of underlying sediments should be used as a tool in determining of potential hazard for soil contamination. For this purpose, comparison of contents of As, Cr, Cu, Hg, Ni, Pb and Zn of soil samples with standard values, the reference soil sample and local background values of underlying sediments was performed. The soil samples are unpolluted regarding to contents of As, Hg, Pb and Zn. All samples have higher contents of Cr and Ni, whereas three samples have higher content of Cu than the limit standard values. Geochemical parameters showed that higher concentration of Cr, Cu and Ni in soils can be attributed to geogenic impact. This conclusion is supported by Chemical Proxy of Alteration and Chemical Index of Weathering values, which indicate intense weathering of sediments. The obtained results show that Kremna area is under slight to moderate hazard if land use change would occur, and prove the importance of geochemical composition of underlying sediments in the interpretation of heavy metal pollution.

Geochemical composition of soils and underlying sediments in the Kremna Basin was investigated. The aim was to assess whether observed heavy metal concentrations in soil samples represent geogenic or anthropogenic contamination. The second objective is to show that geochemical data of underlying sediments should be used as a tool in determining of potential hazard for soil contamination. For this purpose, comparison of contents of As, Cr, Cu, Hg, Ni, Pb and Zn of soil samples with standard values, the reference soil sample and local background values of underlying sediments was performed. The soil samples are unpolluted regarding to contents of As, Hg, Pb and Zn. All samples have higher contents of Cr and Ni, whereas three samples have higher content of Cu than the limit standard values. Geochemical parameters showed that higher concentration of Cr, Cu and Ni in soils can be attributed to geogenic impact. This conclusion is supported by Chemical Proxy of Alteration and Chemical Index of Weathering values, which indicate intense weathering of sediments. The obtained results show that Kremna area is under slight to moderate hazard if land use change would occur, and prove the importance of geochemical composition of underlying sediments in the interpretation of heavy metal pollution.

Liquid thermolysis products of various types of immature kerogen from sedimentary lacustrine rocks from the Valjevo-Mionica basin in Serbia were studied to evaluate the generation potential of kerogen contained in the organic matter (OM) of the rocks, determine the composition of the biomarkers and alkylaromatics in the liquid thermolysis products, and elucidate the effect of Pt4+ and Ru3+ ions (which were added in the form of inorganic salts) on the yield and hydrocarbon composition of the liquid thermolysis products. For this purpose, representative bitumen-free samples A and B of the sedimentary rocks were subjected to thermolysis under various conditions. Rock A contains high amount of immature organic matter, which is dominated by kerogen type I/II and was generated under strongly reduced sedimentation conditions at a high salinity. Sample B is poorer in immature OM than sample A, and the OM of the former contains kerogen type II/III and was generated predominantly in a reduced environment. The content of the liquid products and the concentrations of hydrocarbons obtained in the course of thermolysis of bitumen-free sample A and the typical oil distribution of the biomarkers and alkylaromatics in the thermolysis products confirm a high generation potential of OM in this rock. In all of our experiments on the thermolysis of bitumen-free sample B, the yield of liquid products and hydrocarbons is low. According to the kerogen type, the thermolysis of this rock generates much gases. The Pt4+ and Ru3+ ions (added in the form of simple inorganic salts) increased the yield of liquid (kerogen type I/II) and gaseous (kerogen type II/III) products. During the thermolysis of various type of immature kerogen in the lacustrine sedimentary rocks at a temperature of 400A degrees C, the OM attained maturation corresponding to the early catagenesis level. Saturated biomarkers and alkylaomatics in the thermolysis products of both samples display typical oil distributions. The ty

Liquid thermolysis products of various types of immature kerogen from sedimentary lacustrine rocks from the Valjevo-Mionica basin in Serbia were studied to evaluate the generation potential of kerogen contained in the organic matter (OM) of the rocks, determine the composition of the biomarkers and alkylaromatics in the liquid thermolysis products, and elucidate the effect of Pt4+ and Ru3+ ions (which were added in the form of inorganic salts) on the yield and hydrocarbon composition of the liquid thermolysis products. For this purpose, representative bitumen-free samples A and B of the sedimentary rocks were subjected to thermolysis under various conditions. Rock A contains high amount of immature organic matter, which is dominated by kerogen type I/II and was generated under strongly reduced sedimentation conditions at a high salinity. Sample B is poorer in immature OM than sample A, and the OM of the former contains kerogen type II/III and was generated predominantly in a reduced environment. The content of the liquid products and the concentrations of hydrocarbons obtained in the course of thermolysis of bitumen-free sample A and the typical oil distribution of the biomarkers and alkylaromatics in the thermolysis products confirm a high generation potential of OM in this rock. In all of our experiments on the thermolysis of bitumen-free sample B, the yield of liquid products and hydrocarbons is low. According to the kerogen type, the thermolysis of this rock generates much gases. The Pt4+ and Ru3+ ions (added in the form of simple inorganic salts) increased the yield of liquid (kerogen type I/II) and gaseous (kerogen type II/III) products. During the thermolysis of various type of immature kerogen in the lacustrine sedimentary rocks at a temperature of 400A degrees C, the OM attained maturation corresponding to the early catagenesis level. Saturated biomarkers and alkylaomatics in the thermolysis products of both samples display typical oil distributions. The ty

The species Helicopsyche bacescui in Europe has a disjunct area that is mainly situated south of 45 degrees N latitude and east of 22 degrees E longitude with an isolated smaller part in southwestern Hungary. Recent investigations on the territory of Serbia documented the presence of H. bacescui at 39 localities south of the Danube. The known area of the species is thereby enlarged by about 30%, while its western boundary is relocated by about 440 km. H. bacescui is primarily found in lowlands at elevations of less than 200 m above sea level, frequently in streams that periodically run dry. In Serbia, on the other hand, it is found in permanent highland streams at localities with average elevation of 467 +/- 35 m above sea level. The highest locality at which this species has been found is the spring of the Obudojevica (Western Serbia), which lies at an elevation of 1060 m above sea level. H. bacescui belongs to specific benthic communities that differ from typical macrozoobenthos assemblages found in similar habitats in Serbia by the pronounced dominance of Gammaridae, significant presence of Pisidium species, and absence of other groups of Trichoptera (above all, members of the family Hydropsychidae).

The species Helicopsyche bacescui in Europe has a disjunct area that is mainly situated south of 45 degrees N latitude and east of 22 degrees E longitude with an isolated smaller part in southwestern Hungary. Recent investigations on the territory of Serbia documented the presence of H. bacescui at 39 localities south of the Danube. The known area of the species is thereby enlarged by about 30%, while its western boundary is relocated by about 440 km. H. bacescui is primarily found in lowlands at elevations of less than 200 m above sea level, frequently in streams that periodically run dry. In Serbia, on the other hand, it is found in permanent highland streams at localities with average elevation of 467 +/- 35 m above sea level. The highest locality at which this species has been found is the spring of the Obudojevica (Western Serbia), which lies at an elevation of 1060 m above sea level. H. bacescui belongs to specific benthic communities that differ from typical macrozoobenthos assemblages found in similar habitats in Serbia by the pronounced dominance of Gammaridae, significant presence of Pisidium species, and absence of other groups of Trichoptera (above all, members of the family Hydropsychidae).