Nina Zupančič

Lead contamination in the roadside soils of Slovenia

The level of lead contamination along the roadway Ljubljana to Zagreb was established in 184 soil samples. The samples were taken from two depths (0–5 cm and 15–20 cm) and at different distances from the roadway. The influence of terrain morphology, prevailing winds, geological parent material and type of vegetation was estimated. Heavy traffic is confirmed as main source of lead contamination (average enrichment factor 17) in soils. The highest lead accumulation is localised in the top soil layer and within 10 m from the roadside. Contamination with lead is more pronounced in soil samples from cuttings and slopes than in soils from plains and mounds. Soils derived from carbonate rocks contain higher lead concentration than those derived from other parent material.

Characterization of black deposits in karst caves, examples from Slovenia

Karst caves are important tourism and natural heritage destinations. Within dry cave passages otherwise notable for their rich flowstone decoration, areas with a characteristic black color can sometimes be observed on cave walls and floors and on speleothems. To determine the origin of these black deposits, mineralogical and chemical analyses were carried out in two caves (Postojna Cave and Črna Jama (Kočevje), Slovenia). Qualitative chemical composition was obtained by scanning electron microscopy in conjunction with energy dispersive X-ray spectrometry (SEM/EDS). Organic matter in black deposits was confirmed by the Walkley–Black (wet burning) and loss-on-ignition (LOI, dry burning) methods. Results showed that black deposits from the caves studied could be attributed to natural and anthropogenic causes. Natural causes are related to Mn–Fe oxide precipitation and are probably dependent on microorganism activity. Anthropogenic sources are related to historic (or/and prehistoric) human activities such as cave visitors using torches and fires, events outside the caves such as forest and settlement fires, and recent air pollution. Black deposits show the effect of long-term environmental impact on karst caves and could be included in guided tours of show caves along with a scientific explanation of their causes and origin.

Influence of climate factors on soil heavy metal content in Slovenia

PurposeIn spite of equal lithology, the local climate can affect soils’ geochemical characteristics. We investigated the dependence of heavy metal content on climatic factors according to a hierarchical nested analysis of variance design (ANOVA).Materials and methodsWe examined the heavy metal content in soils developed on the Upper Triassic dolomite at six locations situated at increasing distances from the Adriatic Sea towards inland. We tested the influence of the locations’ position, i.e. climate, vegetation cover, small-scale variability and analytical error. Co, Cr, Cu, Ni, Pb and Zn contents were determined by emission spectrometry.Results and discussionAn initial increase in annual precipitation towards inland is followed by a steady decrease. Very high small-scale variability prevented statistically significant differences from being established at the location level due to the high variance components exhibited. However, the simpler one-way and non-parametric varieties of ANOVA confirmed significant differences in Co, Cr and Ni among locations. The differences are more pronounced in grassland soils where the Cu and Pb contents also differ between locations. There is a positive correlation among annual precipitation, Co, Cr and Ni, and it seems that the prevailing winds can also influence their content in soils.ConclusionsThe Co, Cr, Cu and Ni values are readily the highest in those locations with the greatest precipitation, possibly due to their resistance to leaching. The soils could be additionally enriched by an eolian contribution from the SW located outcropping flysch rocks. The established variability could be due to somewhat different dolomite composition. The reasons for the observed geochemical variability are complex and only partly due to climate.

Application of Scanning Electron Microscopy/Energy-Dispersive X-Ray Spectroscopy for Characterization of Detrital Minerals in Karst Cave Speleothems

Micro-scale observations in karst caves help to identify different processes that shaped local morphology. Scanning electron microscopy/energy-dispersive X-ray spectroscopy inspection of speleothems from two karst caves in Slovenia, Predjama and Črna Jama, confirmed the presence of sub-angular to sub-rounded detrital fragments of clay minerals, feldspars, quartz, Fe-oxides/hydroxides, rutile and Nb-rutile, xenotime, kassite, allanite, fluorapatite, epidote, ilmenite, monazite, sphene, and zircon, between 2 and 50 μm across. These occur in porous layers separating calcite laminae in the clayey coating on the layer below the surface of the speleothems, and are also incorporated within actual crystals. It is likely that they are derived from the weathered rocks of the Eocene flysch. Probably they were first transported into the caves by floodwaters forming cave sediments. Later, depending upon the climate conditions, they were moved by air currents or by water to the surface of active speleothems. They might also be redeposited from overlying soils enriched with wind-transported minerals from the flysch, or from higher passages filled with weathered flysch sediment, by drip water percolating through the fissured limestone. As some of the identified minerals are carriers of rare earth elements, Ti and Zr, their presence could affect any palaeoclimatic interpretations that are based upon the geochemical composition of the speleothems.

Environmental impact of dusting from the Koper port bulk cargo terminal on the agricultural soils

Areas around seaports are prone to environmental damage. In the port of Koper, Slovenia hematite was transhipped during a strong wind. The broader area was accidentally covered with hematite dust. Since the soils had already been geochemically mapped, we repeated the sampling to compare the geochemical composition of the topsoil. No soil contamination was established. The enrichment factors show depletion of majority of elements. According to the distances from the dust source, SiO 2 , Na 2 O and Cr have decreasing, and Fe 2 O 3 increasing trends. The SiO 2 and Cr content correspond to the concentration of quartz rich sand, and the dissolution of carbonate closer to the sea. Co and Ni are probably bound to the clay minerals. Cu, Pb, and Zn could have some anthropogenic contribution.