Thallium in Technosols from Allchar (North Macedonia): Isotopic and speciation insights.

Allchar (North Macedonia) mining area is known for anomalous background Tl concentrations. In this study, we combine accurate detection of Tl stable isotope ratios with data on mineralogy/speciation and chemical extraction of Tl in Tl-contaminated Technosol profiles. We demonstrate that Tl in the studied soils varies significantly in both concentration (500 mg/kg-18 g/kg) and isotopic composition (-1.6 and +3.2 of ε205Tl, a ∼0.5‰ spread), which is due to changes in the phase chemistry and/or mineralogy of Tl. Moreover, the observed 205Tl/203Tl ratios do not reflect the extent to which individual soils undergo Tl isotopic fractionation during mineral weathering and soil formation. Clearly, they reflect the initial isotopic signal(s) of the primary ore or ore minerals, and thus, the general history or type of their genesis. As the Tl carriers, various types of Tl-Me-arsenates, mixtures of jarosite and dorallcharite and minor Mn-oxides predominated. We revealed intense adsorption of Tl by the identified Mn-oxides (≤6.7 at.%). It is hypothesized that these phases are of key importance in the fractionation of Tl isotopes, meaning at this type of secondary oxide-soil solution interface. However, model studies involving primary/secondary components (sulfides, sulfates, oxides and arsenates) are required to understand the mechanisms that may lead to post-depositional Tl isotopic redistribution in soils, as well as Tl isotope systematics in mining wastes in general.

Novel arsenic hyper-resistant bacteria from an extreme environment, Crven Dol mine, Allchar, North Macedonia.

Novel hyper-resistant bacteria were isolated from the Crven Dol mine (Allchar, North Macedonia), arsenic-rich extreme environment. Bacteria were recovered from a secondary mineral mixture, an alteration of hydrothermal realgar rich in arsenates (pharmacolite, hornesite, and talmessite). The sample was recovered from the dark part of the mine at 28 m depth. Three bacterial strains and a bacterial consortium were isolated for their capacity to survive exposure to 32 g/L (209 mM) of arsenite, and 176 g/L (564 mM) of arsenate. The 16S rRNA gene analysis identified bacterial isolates as Stenotrophomonas sp. and two Microbacterium spp. This analysis also revealed that bacterial consortium comprise two Bacteriodetes exhibiting similarity to Olivibacter ginsengisoli and to uncultured bacterium, and one γ-proteobacteria with similarity to Luteimonas sp. Among all isolates Stenotrophomonas sp. exhibited the highest tolerance to As compound as well as the capacity to accumulate As inside the cells. Analysis of genes involved in As-resistance showed that recovered isolates possess the genes encoding the ArsB, Acr3(1) and Acr3(2) proteins, indicating that at least a part of their resistance could be ascribed to As-efflux systems described in isolates obtained from human-polluted environments.

Bacterial and fungal diversity in the lorandite (TlAsS2) mine 'Allchar' in the Republic of North Macedonia.

The Allchar mineral mine is one of the oldest arsenic-antimony mines in the Republic of North Macedonia. The mine is a well-known reservoir of the worldwide purest source of the thallium-bearing mineral, lorandite (TlAsS2). The current study evaluated the bacterial and fungal diversity of three As- and Tl-contaminated sites in Allchar mineral mine. We used a combination of high-throughput sequencing and bioinformatic analyses. Trace metal content was detected using inductively coupled plasma optical emission spectrometry. Our analysis showed the presence of 25 elements and confirmed a high concentration of As and Tl. Alpha diversity indices suggested a high diversity and evenness of bacterial and fungal communities. Bacterial phyla that dominated the environment were Bacteroidetes, Acidobacteria, Planctomycetes, Actinobacteria and Verrucomicrobia. Looking at the genus level, we found the following groups of bacteria: Chryseolinea, Opitutus, Flavobacterium, Pseudomonas, Terrimonas, Sphingomonas and Reyranella. For the fungi genera, we report Tetracladium sp., Coprinellus micaceus, Coprinus sp. from Ascomycota and Basidiomycota phyla in all sites. We also observed a high abundance of the fungal species Pilidium sp., Dendroclathra lignicola, Rosellinia desmazieri, Hypomyces rosellus and Coprinellus disseminatus. This study is the first to identify specific As- and Tl-tolerant fungal (Pilidium sp., Cladophialophora sp., Neobulgaria sp. and Mycena acicula) and bacterial (Trichococcus, Devosia, Litorilinea and Gimesia) genera from Allchar mine, suggesting bioremediation and industrial potential.

How to prevent skin damage from air pollution. Part 1: Exposure assessment.

Both epidemiological and experimental studies have demonstrated the crucial connection between air pollution exposure and skin disorders. The exact mechanisms by which air pollutants mediate skin damage remain largely unknown. Therefore, it is very necessary to investigate the mechanism of air pollution-induced skin damage and explore some potential protective and therapeutic methods. In this review, we focus on the qualitative and quantitative skin exposure assessment methodologies-a relatively new field of interdisciplinary research.

Groundwater quality in alluvial and prolluvial areas under the influence of irrigated agriculture activities.

The aim of this study was to investigate the groundwater pollution from alluvial aquifers lying under surface agriculture activities in two geologically different areas: alluvial and prolluvial. The groundwater in investigated areas is neutral to alkaline (pH 7.05-8.45), and the major dissolved ions are bicarbonate and calcium. Groundwater samples from the alluvial area are characterized by nitrate concentration above the national maximum concentration limit (MCL) at 20.5% of samples [mean value (Me) 6.31 mg/L], arsenic concentrations greater than national MCL at 35.6% of investigated samples (Me 12.12 µg/L) and elevated concentrations of iron (Me 202.37 µg/L) and manganese (Me 355.22 µg/L) at 22.7% and 81% of investigated samples, respectively. Groundwater samples from the prolluvial area did not show significantly elevated concentrations of heavy metals, but the concentration of nitrate was considerably higher (Me 65.06 mg/L). Factor analysis positively correlates As with Mn and Fe, suggesting its natural origin. Nitrate was found in positive correlation with SO42- and Ni but in negative with NH4+, suggesting its anthropogenic origin and the relationship of these ions in the process of denitrification. The t-test analysis showed a significant difference between nitrate pollution of groundwater from alluvial and prolluvial areas. According to the chemical composition of groundwater, the process of denitrification is considered to be the main reason for the reduced presence of nitrate in the groundwater lying under alluvial deposits represented by chalk and sandstones. Denitrification in groundwater lying under prolluvial deposits represented by magmatic and metamorphic rock formations was not observed.

Variation of indoor radon concentration and ambient dose equivalent rate in different outdoor and indoor environments.

Subject of this study is an investigation of the variations of indoor radon concentration and ambient dose equivalent rate in outdoor and indoor environments of 40 dwellings, 31 elementary schools and five kindergartens. The buildings are located in three municipalities of two, geologically different, areas of the Republic of Macedonia. Indoor radon concentrations were measured by nuclear track detectors, deployed in the most occupied room of the building, between June 2013 and May 2014. During the deploying campaign, indoor and outdoor ambient dose equivalent rates were measured simultaneously at the same location. It appeared that the measured values varied from 22 to 990 Bq/m(3) for indoor radon concentrations, from 50 to 195 nSv/h for outdoor ambient dose equivalent rates, and from 38 to 184 nSv/h for indoor ambient dose equivalent rates. The geometric mean value of indoor to outdoor ambient dose equivalent rates was found to be 0.88, i.e. the outdoor ambient dose equivalent rates were on average higher than the indoor ambient dose equivalent rates. All measured can reasonably well be described by log-normal distributions. A detailed statistical analysis of factors which influence the measured quantities is reported.

Results from time integrated measurements of indoor radon, thoron and their decay product concentrations in schools in the Republic of Macedonia.

As part of a survey on concentrations of radon, thoron and their decay products in different indoor environments of the Balkan region involving international collaboration, measurements were performed in 43 schools from 5 municipalities of the Republic of Macedonia. The time-integrated radon and thoron gas concentrations (CRn and CTn) were measured by CR-39 (placed in chambers with different diffusion barriers), whereas the equilibrium equivalent radon and thoron concentrations (EERC and EETC) were measured using direct radon-thoron progeny sensors consisting of LR-115 nuclear track detectors. The detectors were deployed at a distance of at least 0.5 m from the walls as well as far away from the windows and doors in order to obtain more representative samples of air from the breathing zone; detectors were exposed over a 3-month period (March-May 2012). The geometric mean (GM) values [and geometric standard deviations (GSDs)] of CRn, CTn, EERC and EETC were 76 (1.7), 12 (2.3), 27 (1.4) and 0.75 Bq m(-3) (2.5), respectively. The equilibrium factors between radon and its decay products (FRn) and thoron and its decay products (FTn (>0.5 m)) were evaluated: FRn ranged between 0.10 and 0.84 and FTn (>0.5 m) ranged between 0.003 and 0.998 with GMs (and GSDs) equal to 0.36 (1.7) and 0.07 (3.4), respectively.

Influence of a nickel smelter plant on the mineralogical composition of attic dust in the Tikves Valley, Republic of Macedonia.

Mineral phases and their content were determined in attic dust samples collected from 27 houses in the Tikves Valley, Republic of Macedonia. By using quantitative X-ray diffraction, the principal mineral phases were determined to be the serpentinite group (chrysotile, lizardite) and amphibole group of minerals (ribecite, tremolite, actinolite) present in the attic dust samples from this region which are not common constituents of urban dust. Strong correlations existed between these mineral phases in the dust and those in ores processed at a ferronickel smelter plant situated in this region. Spatial distributions of specific mineral phases were made and were consistent with wind directions and predicted deposition (60-70 %) of dust emitted from the metallurgical plant.

Indoor exposure of population to radon in the FYR of Macedonia.

The authors present the results of a year-long survey of the indoor radon concentration levels in the FYR of Macedonia. A total number of 437 dwellings in eight statistical regions were subject to radon concentration measurements by using CR-39 track detectors. The annual mean indoor radon concentration in each measuring site was estimated from the four individual measurements with 3 months duration. The measuring period was from December 2008 to December 2009. The distribution of the results was nearly log-normal. The arithmetic and geometric mean values of the annual mean value of radon concentration were estimated to be 105 ± 84 and 84*/1.9 Bq m(-3), respectively. The annual effective dose due to indoor exposure to radon in the dwellings was estimated to be 2.1*/1.9 mSv y(-1).

Heavy metal contamination of topsoils around a lead and zinc smelter in the Republic of Macedonia.

The results of a first systematic study of spatial distribution of different elements in surface soil over the Veles region (50 km(2)) known for its lead and zinc industrial activity in the recent past are reported. A total of 201 soil samples were collected according to a dense net in urban area and less dense net in rural area. The total of 42 elements were analyzed by epithermal neutron activation analysis (ENAA) and by atomic absorption spectrometry (AAS). The content of elements such as As, Au, Cd, Cu, Hg, In, Pb, Sb, Se, Zn in soil samples around the lead and zinc smelter and in the adjacent part of the town of Veles has appeared to be much higher than in those collected in the surrounding areas due to the pollution from the plant. Thus, the content of Cd (three times); Pb and Zn (two times) is even higher than the corresponding intervention (critical) values according to the Dutch standards. The results obtained by two complementary analytical techniques, AAS and ENAA, are discussed in terms of multivariate statistics. GIS technology was applied to depict the areas most affected by contamination from the lead and zinc smelter.