A geochemical study of snow from the industrial town of Maribor (Slovenia) was performed. Concentrations of 61 elements in meltwater were determined, and a detailed semi-quantitative and qualitative ...analysis of individual PTE-bearing particles deposited in snow was performed with SEM/EDS. The physico-chemical characteristics of meltwater reflect the influence of winter road maintenance (high electrical conductivity and high Ca and Na concentrations close to the main roads) and industrial activities. Particulate matter deposited in snow consists mainly of carbonates and silicates, followed by carbon-rich particles and PTE-bearing particles. A higher abundance of PTE-bearing particles is typical for the industrial zones. The size, morphology and chemical composition of 4415 PTE-bearing particles were studied. They were organised into nine groups based on their characteristics. The majority were assigned to the group of
Fe
-
oxides,
which includes mostly angular particles of unidentified origin. Several groups of particles of anthropogenic origin were determined, mainly from industrial metal-processing activities. These particles include
spherical Fe
-
oxides, Fe
-
alloys, other metal alloys
and
spherical Si
-
particles
.
Spherical Fe
-
oxides
are typical for the Tezno industrial zone, while
Fe
-
alloys
, namely Fe–Cr (Cu, Mn, Ni) shavings and
other metal alloys
(Cu–Zn (Cl, Fe) shavings) are typical for the Melje industrial zone. The presence of naturally occurring mineral particles (e.g. zircon, ilmenite, monazite) reflects the influence of natural/geogenic sources on the composition of particulate matter deposited in snow. The presented study confirmed that snow is a very promising medium for the geochemical study of urban environments, especially for the identification of anthropogenic sources of particulate matter.
This paper provides an overview of the physical and chemical landscape changes that have occurred at four reference sites due to historical mining and smelting activities within Slovenia, and their ...comparison with similar sites around the World. Literature review has been made with the intention to identify major pollutant sources, its dispersion control factors, and effects. The four reference sites are Idrija, with more than 500‐year Hg mining and ore smelting history, the Meža Valley, also with a 500‐year PbZn mining and smelting history, the Celje area where Zn was smelted for 100 years and the Drava River alluvial plain, which is contaminated because of historical PbZn mining upstream. Based on the comparison between the four abovementioned reference sites and similar sites around the world that are situated in different landscapes and climates, we identified major sources of contamination, which are the erosion of mine and ore processing wastes, and atmospheric emissions of metal‐containing particles from smelters. In the first case, major control factors are rainfall pattern and river gradient, controlling erosion and sediment deposition patterns. In the second case, the prevailing control factors are topography and the dominant wind directions.
Considerable amounts of gaseous elemental mercury (Hg0) can be released into the atmosphere from Hg-enriched substrates, such as those from former mining areas, posing a potential environmental ...threat. In this work, Hg0 fluxes at the soil–air interface under natural vegetation covers were measured in various locations within the Idrija Hg mining area (Slovenia) and its surroundings. Sites were selected in order to compare Hg0 fluxes from both forest soils heavily impacted by historical ore roasting and urban soils characterised by a different degree of Hg enrichment due to the natural occurrence of Hg in rocks or recent mining and roasting processes. Replicate measurements at each site were conducted using a non-steady state flux chamber coupled with a real-time Hg0 analyser (Lumex RA-915M). Moreover, topsoil samples (0–2 cm) were analysed for Hg total concentration and speciation. Cinnabar was the predominant Hg form in almost all the sites. Despite Hg0 being undetectable in soils using thermo-desorption, substantial emissions were observed (70.7–701.8 ng m−2 h−1). Urban soils in a naturally enriched area showed on average the highest Hg0 fluxes, whereas relatively low emissions were found at the historical roasting site, which is currently forested, despite the significantly high total Hg content in soils (up to 219.0 and 10,400 mg kg−1, respectively). Overall, our findings confirm that shading by trees or litter may effectively limit the amount of Hg0 released into the atmosphere even from extremely enriched soils, thus acting as a natural mitigation.
One of the main sources of potential chronic exposure to potentially toxic elements is household dust, especially in an environment with known point sources of PTE pollution. The literature review ...clearly shows that the total concentrations of an element in the environment do not provide information to predict its bioavailability. The aim of the present study was to evaluate the oral and inhalation bioaccessibility of PTE present in household dust in the small town of Idrija, the site of the former mercury mine. Unified bioaccessibility method was used to assess oral bioaccessibility of PTE in the stomach and intestine, while inhalation bioaccessibility was assessed by extraction of household dust samples with two synthetic extraction solutions—Gamble’s solution (GS) and artificial lysosomal fluid (ALF). A low bioaccessibility of mercury was observed in all synthetic solutions (less than 3%). The highest bioaccessibility of PTE was observed in ALF solution, especially for Zn, Pb and Cd. Only a slightly lower bioaccessibility of these three elements was also observed in the stomach, while the bioaccessibility of other elements in the gastric phase was less than 40%. In general, the bioaccessibility of all elements decreased in the intestine. With the exception of Cr, the lowest bioaccessibility of the elements was observed in GS. Daily ingestion and inhalation doses of PTE from household dust were calculated and their values were below the available recommended or tolerable daily intakes of PTE from food according to the European Food Safety Authority.
Ombrotrophic peatlands contain a very small percentage of mineral matter that they receive exclusively from atmospheric deposition. Mineral matter deposited on the Šijec bog was characterized using ...scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We collected solid atmospheric deposition from snow, rainwater, and using passive samplers. Samples were collected at average atmospheric conditions and after two dust events. Size, morphology, and chemical composition of individual particles were determined. We distinguished four main particle groups: silicates, carbonates, organic particles, and Fe-oxyhydroxides. Silicate particles are further divided into quartz and aluminosilicates. Proportions of these groups vary between samples and between sample types. In all samples, silicate particles predominate. Samples affected by dust events are richer in solid particles. This is well observed in passive deposition samples. Carbonates and organic particles represent smaller fractions and are probably of local origin. Iron-oxyhydroxides make up a smaller, but significant part of particles and are, according to their shape and chemical composition, of both geogenic and anthropogenic origin. Estimated quantity and percentage of main groups vary throughout the year and are highly dependent on weather conditions. Dust events represent periods of increased deposition and contribute significantly to mineral matter input to peatlands.
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.
Total Hg concentrations and Hg speciation were determined in soils and attic dust in a 160 km
2 area around Idrija mercury mine. Attic dust as well as a sample of soil was collected at 100 locations. ...Mercury phases were separated into cinnabar and non-cinnabar compounds via a thermo-desorption technique. The amount of the non-cinnabar fraction is important since it is potentially bioavailable and results are needed for further risk assessment studies.
The concentrations of Hg in attic dust are many times higher than in surrounding soils and the attic dust/soil ratio changes with distance. The highest concentration ratios were identified at the greatest distance from the source of pollution and the lowest close to the source of pollution.
This confirms the impact of air emissions on the wider area around Idrija. Furthermore the spatial mercury distribution in the attic dust shows that the influence of atmospheric emissions caused by the Idrija smelter resulted in impacts on the environment on a regional scale. The portions of non-cinnabar compounds increase with distance from the mercury source in both sampling media. Non-cinnabar fractions were found to be enriched in distant areas where fine grained material was deposited. There were two different transport mechanisms of dust particles and gaseous Hg(0) during the mercury production period. Obviously coarse grained particles, with mostly cinnabar-bound Hg settled in the immediate vicinity of the smokestack of the smelter, whereas the fine grained fraction could be dispersed further ahead. This is represented by the percentage of cinnabar-bound Hg in attic dust and soil decreasing with distance from the smelter. Gaseous Hg(0) is probably bound to fine and ultrafine aerosols with longer residence time against deposition. The consequence is that fine grained material with Hg
2+ and Hg
0 prevails in remote localities and is bound in soils and dust with matrix and organic matter as non-cinnabar mercury compounds.
The distributions of mercury species in attic dust and soils along the Idrijca River show that in the region from Idrija to Spodnja Idrija the portions of cinnabar and non-cinnabar are about equal, while in the upper and in the lower Idrijca valley non-cinnabar bound mercury prevails.
The applicability of attic dust for tracing the mercury halo in the Idrija area was successfully shown.
The potential environmental impact of historical mining and ore processing on stream sediments and water was studied in a small siderite iron ore deposit with diverse sulfide mineral paragenesis. The ...main aim was to characterize solid carriers of potentially toxic elements (PTEs) in stream sediments and mine waste, to understand their fate in fluvial systems. General mineralogy (X-ray powder diffraction) and individual solid PTE carriers (scanning electron microscopy/energy dispersive spectroscopy) were correlated with the geochemical composition of stream sediments, mine waste, and stream waters (inductively coupled plasma mass spectrometry). Primary solid PTE carriers were pyrite, chalcopyrite, sphalerite, Hg-bearing sphalerite, galena, and siderite. Slightly alkaline and oxidizing conditions in stream water promoted the transformation of primary phases into secondary PTE carriers. Fe(Mn)-oxide/oxyhydroxides were major sinks for Pb, Zn, and As. Compared to background levels, Co (14.6 ± 2.1 mg/kg), Cu (30 ± 2.9 mg/kg), Ni (32.1 ± 2.9 mg/kg), Pb (64.5 ± 16.4 mg/kg), Zn (175.3 ± 22.5 mg/kg), As (81.1 ± 63.7 mg/kg), and Hg (2 ± 0.8 mg/kg) were elevated in mining area. Mine waste contained similar PTE carriers as stream sediments, but much higher PTE contents. Prevailingly low PTE concentrations in streams, with the exception of As (1.97 ± 2.4 µg/L) and Zn (4.5 ± 5.7 µg/L), indicate the stability of PTE carriers. Environmental effects were not significant, and additional monitoring is recommended.
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