The main objective of this study is to map multi-element geochemical anomalies in soil on a regional scale. We aimed to determine and evaluate the baseline geochemical values and main geochemical ...trends in soil that may serve as reference values against any future changes. A total of 817 topsoil samples (0–10 cm) were collected in a 5 × 5 km grid and analyzed for 35 elements using ICP-ES after multi-acid digestions (HClO4/HNO3/HCl/HF) and 53 elements using ICP-MS after modified aqua regia digestion (HCl/HNO3/H2O). The analytical results for the two different digestion methods (multi-acid digestion vs. aqua regia) were also compared for each chemical element. Multivariate statistical methods were applied to identify the geochemical trends and main sources of trace elements over the territory of Slovenia. Based on these results, seven natural and one mixed natural/anthropogenic geochemical association were established. The contents and trends of the determined factors are presented according to 8 natural units, 4 drainage areas, and geological units characteristic of Slovenia. The identified anthropogenic geochemical association combines toxic elements (Ag, Bi, Cd, Hg, P, Pb, S, Sn, and Zn). Increased values of these elements can be found in mining areas and metallurgic centers, in Quaternary sediments of the Sava River, and Adriatic Basin as the consequence of past mining activities and in the Julian Alps, where their origin could be connected to the atmospheric deposition.
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CEKLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The aim of this paper was to test the new sampling media—earthworm casts in a highly contaminated area. The investigation was carried out at the ancient Hg ore roasting site Pšenk in the surroundings ...of Idrija, where extremely high Hg contents in soils and SOM were determined in previous investigations. 32 earthworm cast samples were collected in the research grid 30×30m in order to compare the Hg contents and spatial distribution in earthworm casts to the values and distributions in SOM and soil (0–15cm). Extremely elevated Hg concentrations were determined in earthworm casts from the studied area ranging from 5.4 to 4330mg/kg with the median of 31mg/kg. The Hg values in casts are somewhat lower than in soil (6.3–8600mg/kg) and slightly higher compared to soil organic matter (SOM) (1.5–4200mg/kg). Strong correlation (r²=0.75) between Hg contents in casts and soil was found, while correlation between casts and SOM was positive but weaker (r²=0.35). Spatial distribution of Hg in earthworm casts show the highest concentrations in the central part of investigated area, similar to the distribution in soil. Hg contents rapidly decrease from the center toward the margins of the studied area, where they reach values of less than 50mg/kg. It was shown that Hg contents and dispersion in casts are comparable to those in soil, which indicates that at investigated area soil contamination is strongly reflected in contamination of earthworm casts.
► We compare Hg contents in soil, SOM and earthworm casts. ► The determined Hg contents are in the order of soil>earthworm casts>SOM. ► There is strong correlation between Hg contents in casts and soil. ► Soil contamination is strongly reflected in contamination of earthworm casts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
In this study an interesting sampling medium - earthworm casts was examined in a highly Hg contaminated area. Enrichment factor (EF) has been applied to assess elevated concentrations of analyzed ...elements in earthworm casts and to determine elevated concentrations of these elements in soils and casts with regard to European average concentrations in topsoil. In a previous study (Teršič & Gosar, 2012) it was shown that Hg contents and dispersion in casts from studied roasting site are comparable to those in soil, which indicates that soil contamination is substantially reflected in contamination of earthworm casts. Therefore the comparison between elemental concentrations in earthworm casts and soil was investigated with the intention to assess the reflection of possible soil contamination in casts. Besides Hg contamination, elevated concentrations of As, Ca, Cd, Mo, Pb and U were also determined in earthworm casts. The calculated EFs show moderate enrichment of casts with Ca, Sr and P and minimal enrichment with Mg, Zn and Cu. Cast, SOM (surface organic matter rich soil layer) and soil enrichments with regard to the European averages show extreme enrichment of all studied media with Hg, followed by significant enrichment with Mo and Cd and moderate enrichment with As. Spatial distributions of analyzed elements in casts mostly show similar pattern as in soil, however, because of the different nature of different earthworm species and specific properties of different elements, the data about cast contamination can only serve as an approximate prediction about the dispersion and distribution of contaminant in soil.
A regional geochemical survey was conducted, covering the entire territory of Slovenia. Medium-density soil sampling was performed in a 5×5km grid, mercury concentrations were analysed and a map of ...mercury spatial distribution was constructed. The determined mercury concentrations revealed an important difference between the western and the eastern parts of the country. A huge anomaly in the western part is the consequence of environmental contamination due to the 500-year history of mining and ore processing in the Idrija mercury mine and partly due to Hg containing rocks on outcrops. Slightly elevated Hg concentrations revealed in the Ljubljana-Kranj and Celje basins indicate urban pollution due to industry, traffic and the use of mercury-containing products. It was established that, besides anthropogenic impacts, lithological and climatic characteristics that determine the type of soil also influence the distribution of mercury in soils. The data were compared to a previously conducted low-density geochemical survey (sampling grid 25×25km, n=54) and to the regional geochemical data set supplemented by local high-density sampling data (irregular grid, n=2835). Comparing high-, medium- and low-sample density surveys, it was shown that higher sampling density allows the identification and characterization of anthropogenic influences on a local scale, while medium- and low-density sampling reveal general trends in the mercury spatial distribution, but are not appropriate for identifying local contamination in industrial regions and urban areas.
•Regional geochemical survey was conducted.•Hg distribution in Slovenian soils was determined.•High and low sample density surveys were compared.•A distinct Hg anomaly around Idrija area was revealed.•The variability of the spatial distribution of Hg mainly depends on pollution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
Numerous roasting vessels fragments can be found at ancient roasting site areas in the surroundings of Idrija town, which were used for ore roasting in the first 150 years of Hg production in Idrija. ...The earthen vessels fragments lay just below the surface humus layer and in some parts they stretch more than 1 meter deep; they arecovered with red (cinnabar) or black (metacinnabar) coatings.SEM/EDS analysis of roasting vessels fragments and soil samples from roasting site areas P{enk and Frbejžene trate was performed in order to characterize the solid forms of Hg in applied sampling material. Mercuric sulphide HgS was found to be the main mercury compound present in the samples. Analysis of earthen vessels fragmentsshowed abundant HgS coatings on the surface of ceramics, forming either crust-like aggregates on matrix or isolated grains. Some well-shaped grains with indicated structure and the size of up to 200 μm could also be observed. In soil HgS was present as powder-like concentrations scattered in soil samples, frequently coating silicate and quartz crystals and clay-minerals. Polycristalline, mercury- and sulphur- rich particles comprising silica, clay mineralsand Al-, Fe- and Mg-oxides that were also observed in the samples were interpreted as soil aggregates infiltrated by mercuric and sulphur vapours and by liquid mercury spilled during roasting. These particles suggest a possible presence of mercury-sulphur associations other than HgS.
Mercury (Hg) solubility and reactivity in soils at two extremely contaminated ancient small scale cinnabar roasting sites in the surroundings of the Hg mining area of Idrija (Slovenia) were ...determined in order to assess the mobility of Hg in the aqueous phase and to evaluate the extent of leaching of Hg into Idrijca River and further downstream. Water leaching experiments were performed on soil and SOM (soil organic matter) samples from historical roasting sites Pšenk and Frbejžene trate. The determined concentrations of leachable Hg in soil samples from the studied areas range from 16 to exceptionally high concentration of 18,000μg/kg, representing 0.0002 to 1.1% of total Hg in these samples, while in SOM samples leachable Hg concentrations range between 13.3 and 6000μg/kg, which corresponds to 0.0017–0.074% of total Hg determined in SOM. The soluble Hg concentrations in investigated soil profiles range from 183 to 18,000μg/kg (0.038–1.7% of total Hg). On the average, more than 90% of soluble Hg occurs in a non-reactive complex bound form, suggesting the preferential binding of Hg to humic matter. Soluble Hg in studied soil profiles generally increases with depth. The obtained results show that Hg is effectively transported to deeper soil layers, mainly as soluble organic complexes. It is estimated that there is still about 10kg of soluble Hg stored in soils of the investigated roasting sites, which is continuously leached to surface waters and deeper into the soil.
•Water leaching experiments were performed on soil and SOM samples.•Total soluble, complex-bound and reactive Hg was defined.•Extremely high concentrations (up to 18,000μg/kg) of soluble Hg were determined.•More than 90% of soluble Hg occurs in a non-reactive complex bound form.•We estimate that soluble Hg stored in soils is mobilized to the groundwater.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Analysis for 35 chemical elements (Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, K, La, Mg, Mn, Mo, Na,Ni, P, Pb, S, Sb, Sc, Se, Sr, Th, Ti, Tl, U, V, W, Zn) was performed in soil and SOM ...(soil organic matter; 0–5 cm) at theancient roasting site P{enk in the surroundings of Idrija, which is highly contaminated with Hg. It was estimatedthat natural values of Al, Ba, Fe, K, Mn, Ni and Zn show normal distribution, while for the elements As, Au, Bi, Ca,Cd, Co, Cr, Cu, Ga, La, Mg, Mo, P, Pb, Sc, Se, Sr, Th, Tl, U in V the logarithms of elemental contents were considerednormally distributed. Contents of the analyzed elements in the sampling material are mostly within the normalvalues for soils as also within Slovenian and European averages for soil. High contents of As were determined insoils from investigated roasting site, reaching as much as 122 mg/kg in the depth of 5–20 cm. Additionally Cd, Mo,Pb and U contents in the soil (5–20 cm) are higher compared to natural soils. Cd and Mo show somewhat increasedcontents also in SOM from studied roasting site.
The distribution and transport of Hg and other elements were studied in aquatic systems draining contaminated ancient Hg ore roasting sites Pšenk and Frbejžene trate in Idrija surroundings. Hg ...concentrations in sediments at the studied roasting site areas were found extremely high, ranging from 18 to 1240mg/kg (average 387mg/kg) in the <0.063mm grain-size fraction, and from 48 to 1080 (average 456mg/kg) in the <0.125mm fraction. Further downstream along the Padarjeva grapa Stream, which drains both contaminated areas, Hg concentrations were 330–2040 (average 721mg/kg; for <0.125mm) and 380–840 (average 531mg/kg; for <0.04mm). Increased Hg concentrations were found in the Idrijca River sediments downstream of the Padarjeva grapa Stream confluence. The results of our investigation have proved that Hg-loaded materials are not only still present at the roasting sites, but are intensively eroded and transported downstream during high waters. Consequently they have significant influence on the Idrijca River sediment contamination. Delivery of Hg contaminants from historically contaminated roasting sites via Padarjeva grapa Stream during heavy rainfalls was most intense during operation of the roasting sites, but remains an ongoing issue.
•Stream sediments are highly contaminated with Hg.•Strong effect of ancient Hg ore roasting sites on the Idrijca River sediment contamination•Delivery of Hg by storm waters from ancient roasting sites is an ongoing issue.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
Five centuries of mining and processing of mercury ore in the Idrija area have resulted in widespread contamination of different environmental compartments. Environmental impacts on a regional and ...local scale, caused by atmospheric emissions from the Idrija ore roasting plant, were established in the investigations of mercury spatial distribution in soil and attic dust in 160 km
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area. Very high values were determined in the Idrijca River valley, and they decrease exponentially with the distance from Idrija. Mercury concentrations in attic dust are higher than in surrounding soils and the attic dust/soil ratio changes with distance. Measurements of mercury in the air confirmed widespread dispersion of mercury and showed highly elevated mercury concentrations around roasting plant and mine ventilation shaft. Beside, systematic monitoring of mercury contents in the stream sediments has demonstrated that huge amounts of mercury are stored in areas where ancient overbank sediments were deposited, and there was no decrease in mercury concentration in active sediments during the last 15 years. Recently, interesting and extremely polluted locations of historical small-scale roasting sites in the Idrija surroundings were discovered. Ongoing geochemical study aims to determine the extreme pollution and significance of these sites for wider contamination of soils and aquatic systems. Presented studies have shown that Hg mining in Idrija caused intense pollution of local and regional environment including the aquatic systems in the Gulf of Trieste, which is seen as the final sink of a major part of the Hg stored in soils and river sediments in the Idrija area.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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