The geochemical investigation of topsoil from the industrial-urban area in the southern part of Sisak was carried out. The concentrations, spatial distribution, solid forms and sources of Ba, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, W and Zn were determined. The investigation showed that the content of the metals in the industrial zone is increased compared to the rest of Sisak area. With the use of methodology developed during the project, it was established, based on the morphological, chemical and mineralogical properties of metal-bearing particles, that the studied elements predominantly originate from anthropogenic sources, such as steelworks, recycling of steel scrap, ferroalloys production and, to a lesser extent, pedological processes in the soil and parent material.
COBISS.SI-ID: 2637653
A comprehensive geochemical investigation of potentially harmful elements (PHEs) in household dust from the town of Idrija (Slovenia), once a world-famous Hg mining town that is now seriously polluted, was performed for the first time. After aqua regia digestion, the content of mercury (Hg), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb) and zinc (Zn) was measured. PHE-bearing particles were recognised and observed by scanning electron microscopy and energy-dispersive spectrometry before and after exposure to simulated stomach acid (SSA). Mercury binding forms were identified by Hg thermal desorption technique and gastric bioaccessible Hg was estimated after SSA extraction by ICP-MS. With regard to rural and urban background values for Slovenia, high Hg content (6–120 mg/kg) and slightly elevated As content (1–13 mg/kg) were found. Mercury pollution is a result of past mining and ore processing activities. Arsenic content is potentially associated with As enrichment in local soils. Four Hg binding forms were identified: all samples contained Hg bound to the dust matrix, 14 samples contained cinnabar, two samples contained metallic Hg (Hg0), and one sample assumingly contained mercury oxide. After exposure to SSA, Hg-bearing phases showed no signs of dissolution, while other PHE-bearing phases were significantly morphologically and/or chemically altered. Estimated gastric Hg bioaccessibility was low ((0.006– 0.09 %), which is in accordance with identified Hg binding forms and high organic carbon content (15.9–31.5 %) in the dust samples.
COBISS.SI-ID: 2520405
In order to determine the origin of sulphate minerals on speleothems with black coatings in limestone caves, Črna jama cave near Kočevje was investigated, in which the presence of human activities was already detected. SEM/EDS analysis of morphology of sulphate minerals, combined with XRD analysis, showed that they are authigenic gypsum and scarce barite microcrystals. In order to determine the source of sulphur, which is a major constituent of cave sulphates, stable sulphur isotope analysis of gypsum and parent rock (limestone) was carried out. Analyses have shown that a more likely source of sulphur in sulphate minerals is biomass burning and not parent rocks. This shows the great human impact on environmental pollution in the past and cave mineralogy.
COBISS.SI-ID: 1368670
The paper deals with determination of sources and age of black deposits on speleothems in Postojna Cave and Predjama. In order to confirm the hypothesis that black deposits are the result of extensive fires in Holocene, the morphology and chemical composition of black deposit material, obtained from speleothems by dissolution with acid, and charcoal from soils in the vicinity of caves were studied by SEM/EDS. The age of black deposits and charcoal in soil was determined by radiocarbon dating. The results of SEM/EDS analysis showed that black deposit material is morphologically and compositionally very similar to oxidized charcoal in soil, and that it is most likely charred plant remains resulting from biomass burning, which was confirmed by stable carbon isotope measurements. Radiocarbon dating showed a match between the age of black deposits and the age of charcoal in soil from different depths, which corresponded to Early Holocene (Mesolithic) and Late Holocene (Eneolithic, Iron Age, Middle Ages). These ages, combined with archaeological data, have shown that the source of the oldest black deposits is natural forest fires, while younger deposits are a consequence of human activities, either burning fires at the cave entrances or human-induced forest fires. In this study, the methodology for determination of sources by using SEM/EDS analysis of morphology and chemical composition of individual particles, in combination with other methods, was successfully used in determination the sources of pollution of paleoenvironment.
COBISS.SI-ID: 1345886
Characterization of morphology and chemical composition of secondary metal-bearing phases on used dental amalgams, resulting from long-term exposure to oral environment, was carried out. Using SEM/EDS individual particles analysis, numerous secondary phases represented by chemically and morphologically complex Hg, Cu, Sn, Ag and Zn sulphides and oxides/hydroxides and scarce sulphates and phosphates were identified. Secondary phases mostly occur as porous microcrystalline aggregates and crusts, which are stable in oral environment and represent trapping media for dissolved potentially toxic metals. Simplified PHREEQC calculations of solubility of secondary metal-bearing phases under simulated gastric conditions have shown, based on morphology and chemical composition of secondary metal-bearing phases, that Sn, Zn and Cu are most bioaccessible both under reducing and oxidizing conditions, and that Sn hydroxychlorides, Sn oxides/hydroxides, Sn sulphates/hydroxysulphates, Zn sulphides and Cu sulphides contribute the most to bioaccessibility of these metals. The study shows the use of methodology for identification and characterization of metal-bearing phases using SEM/EDS and assessment of stability of phases in gastric environment based on data on mineralogy, morphology and chemical composition of phases.
COBISS.SI-ID: 2619221