Hakite, ideally Cu 10 Hg 2 Sb 4 Se 13 , is a Se-dominant member of the tetrahedrite group occurri... more Hakite, ideally Cu 10 Hg 2 Sb 4 Se 13 , is a Se-dominant member of the tetrahedrite group occurring at only a few localities in the World. A new occurrence of this mineral in the Príbram uranium and base-metal ore district, Central Bohemia, Czech Republic, is reported in this paper. Hakite was found to be locally abundant and was identified in several samples with Se mineralization. Three chemically distinct types of hakite were distinguished based on electron microprobe study, Hg-rich hakite (hakite sensu stricto), Zn-rich hakite and Cd-rich hakite. Hg-hakite dominates among the samples studied. Its average empirical formula based on 29 apfu (n = 54) is (Cu 5.61 Ag 0.39) Σ6.00 Cu 4.00 (Hg 1.61 Zn 0.20 Cu 0.19 Cd 0.15 Fe 0.04) Σ2.19 (Sb 3.85 As 0.28) Σ4.13 (Se 11.55 S 1.14) Σ12.69. Less common is the Zn-hakite, (Cu 5.80 Ag 0.20) Σ6.00 Cu 4.00 (Zn 1.33 Hg 0.42 Cd 0.22 Cu 0.18 Fe 0.01) Σ2.16 (Sb 3.85 As 0.26) Σ4.11 (Se 10.92 S 1.81) Σ12.73 (n = 22), and rare Cd-hakite has an empirical formula (n = 7) of (Cu 5.84 Ag 0.16) Σ6.00 Cu 4.00 (Cd 1.27 Zn 0.60 Cu 0.10 Hg 0.07 Fe 0.02) Σ2.06 (Sb 4.00 As 0.19) Σ4.19 (Se 12.14 S 0.61) Σ12.75. The refined unit cell of Hg-hakite from Príbram, obtained from powder X-ray diffraction data, is a = 10.8783(3) Å with V = 1287.3(1) Å 3 (Z = 4, for the cubic space group I43m). Structure refinement from the precession electron diffraction data collected on the transmission electron microscope (R = 24.4% for 424 observed reflections), confirmed that hakite is isostructural with tetrahedrite. The evolution of hydrothermal fluids, from which Se mineralization formed, suggests a distinct enrichment in sulfur and depletion in selenium over the time span of crystallization.
Weathering of 450 years old mine wastes after silver mining at Geister vein in the Jáchymov ore d... more Weathering of 450 years old mine wastes after silver mining at Geister vein in the Jáchymov ore district (Czech Republic) and migration of uranium were studied. Specific gamma-ray activity of 226 Ra, measured by field gamma-ray spectrometry, varies from 38 Bq/kg (3 ppm eU) to 3816 Bq/kg (309 ppm eU) in the observed area. The most active material forms the top layer of the dump. The gamma-ray activity of the top layer is caused mainly by 226 Ra. Uranium is leached from upper layer and accumula ted in fossil soils beneath. U-micas were studied using X-ray powder diffraction and EDA. The following succession of supergene alteration was found: autunite meta-autunite bassetite oxidized bassetite.
Abstract The costs of construction waste handling, a scarcity of landfill sites, and requirements... more Abstract The costs of construction waste handling, a scarcity of landfill sites, and requirements for sustainable construction have placed recycling of concrete—the most abundant construction material in the world—under scrutiny. Unlike recycling of aggregates, utilization of sub-sieve fractions from recycled concrete has not yet been adopted in the construction industry. In this study, we investigate the possibility of recovering residual anhydrous clinker embedded in grains of stripped mortar within these fines. Different samples of waste concrete were finely ground and studied using microscopy and chemical analyses to assess the amount of residual clinker. Its contribution to hydration processes was measured by calorimetry, and the impact of recycled concrete fines on mechanical properties of cement pastes was tested. The results indicate that residual anhydrous clinker is present in waste concrete and can be recovered by grinding. Replacing Portland cement with the recycled material in pastes led to a significant increase of tensile strength, while deterioration of compressive strength was negligible when the concrete fines contained higher amounts of residual clinker and when the amount of fines did not exceed 30% of Portland cement weight.
The lead (Pb) content and 206 Pb/ 207 Pb ratio were studied in three peat profiles dated by 210 P... more The lead (Pb) content and 206 Pb/ 207 Pb ratio were studied in three peat profiles dated by 210 Pb from the border-area mountains of the Czech Republic and in the tree rings of spruce trees located in their immediate vicinity. Both archives document a similar progress in Pb pollution levels and Pb accumulation in the 1950'se1990's. The deposition rate (DR) of Pb in peat bogs attained maximum values of 40 mg Pb m À2 y À1 in the "Black Triangle" area and 15 mg Pb m À2 y À1 in more distant areas in this period. The Pb isotopic record of both archives from the contaminated area exhibit a similar trend in the presence of the individual sources of Pb, in which Pb derived from combustion of coal predominates. The peat cores in more distant areas document well the effect of automobile Pb in the atmosphere and its substantial reduction after 2000. The two archives differ in individual patterns following from the differences in the rates of formation of their biomass and different means of deposition of Pb in the two archives.
Kavková et al. Tunguska Event-Related Environmental Disturbance FIGURE 1 | (A) The Tunguska regio... more Kavková et al. Tunguska Event-Related Environmental Disturbance FIGURE 1 | (A) The Tunguska region and the study site-Suzdalevo Lake (SUZ). The bold black line shows the border of the TE tree fall area the black cross shows the TE epicenter. The area of the Tunguska State Reserve is shown in grey. (B) Geographical location of Suzdalevo Lake within Russia. (C) Bathymetric map of Suzdalevo Lake. The white cross indicates the position where two sediment cores (SUZ1 and SUZ3) were taken.
<p>Vertical profiles of Tl, Pb and Zn concentrations and T... more <p>Vertical profiles of Tl, Pb and Zn concentrations and Tl and Pb isotopic ratios in a contaminated peatland/fen (Wolbrom, Poland) were studied to address questions regarding (i) potential long-term immobility of Tl in a peat profile, and (ii) a possible link in Tl isotopic signatures between a Tl source and a peat sample. Both prerequisites are required for using peatlands as archives of atmospheric Tl deposition and Tl isotopic ratios as a source proxy. We demonstrate that Tl is an immobile element in peat with a conservative pattern synonymous to that of Pb, and in contrast to Zn. However, the peat Tl record was more affected by geogenic source(s), as inferred from the calculated element enrichments. The finding further implies that Tl was largely absent from the pre-industrial emissions (>~250 years BP). The measured variations in Tl isotopic ratios in respective peat samples suggest a consistency with anthropogenic Tl (ε<sup>205</sup>Tl between ~ -3 and −4), as well as with background Tl isotopic values in the study area (ε<sup>205</sup>Tl between ~0 and −1), in line with detected <sup>206</sup>Pb/<sup>207</sup>Pb ratios (1.16–1.19). Therefore, we propose that peatlands can be used for monitoring trends in Tl deposition and that Tl isotopic ratios can serve to distinguish its origin(s). However, given that the studied fen has a particularly complicated geochemistry (attributed to significant environmental changes in its history), it seems that ombrotrophic peatlands could be better suited for this type of Tl research.</p>
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Groundwater inflows showing notable natural radioactivity have been found at the northern end of ... more Groundwater inflows showing notable natural radioactivity have been found at the northern end of the Holešovice cable tunnel close to the Čimice Grove. This groundwater originates from the Barrandian Neoproterozoic slates of the Blovice accretionary complex, Belt I (Šárka-Zbiroh Belt) at depths approximately 100 meters below the surface, occurring along 50 meter profile of the cable tunnel. Water springs are dispersed in the spring area, with the total discharge of 2 L/s. Groundwater is cold (T ~ 11.1 – 12.3 °C), neutral (pH ~ 6 – 7.48), suboxic to oxic (Eh (ORPH) ~ 177 up to 418 mV), of a hydrochemical type Ca-Mg-HCO3, total mineralization being around 702 mg/L. Radon activity (222Rn) varies between 415 and 1195 Bq/L and radium activity (226Ra) ranges between 0.18 and 5.3 Bq/L. Activities of Rn and Ra are relatively high. Currently, this is the most radioactive water within Prague agglomeration. This water is relatively aggressive as well, causing damage to the concrete lining of t...
Continuous basalt fibres (CBF) - a novel class of man made mineral fibres - possess good thermal ... more Continuous basalt fibres (CBF) - a novel class of man made mineral fibres - possess good thermal and electric insulating properties. CBF (in form of filaments or fabrics) are suitable materials for flame retarding and other thermally loaded applications (eg, fire blocking interliners in ...
Uraniferous bitumens found in black shales from the Permian rocks at Vrchlabí in the Krkonoše Pie... more Uraniferous bitumens found in black shales from the Permian rocks at Vrchlabí in the Krkonoše Piedmont Basin (Czech Republic) were described and characterized petrologically and mineralogically. The Permian sediments originated from weathering products in metasediments and granitoids of the Krkonoše–Jizera and Orlice–Sněžník crystalline complexes. The organic matter contained up to 4.8 wt.% uranium, as uraninite grains. Elements associated with uraninite, such as Pb, Zr, Cu, and As, may have accumulated from epigenetic fluids in layers rich in organic matter during their late diagenesis. The bitumen structures were extremely heterogeneous, a feature attributed to the radiolytic effects of uranium. Amorphous bitumens, alternating with various forms of nodular and corroded bitumen types from multiple generations, were present. Low and highly altered bitumens with weak anisotropy were recognized, together with halo zones, with reflectance up to 4.37%. The halo zones differed in size, b...
The content and the isotopic composition of lead (Pb) were studied in a peat deposit on the ridge... more The content and the isotopic composition of lead (Pb) were studied in a peat deposit on the ridge of the Brdy Hills, in the vicinity of the Příbram metallurgical works, in the Czech Republic. Quadrupole ICP MS was employed to determine the elemental composition and 206 Pb/ 207 Pb and 208 Pb/ 206 Pb isotope ratios. The individual layers were dated using α spectrometric measurement of the 210 Pb activity. The historical time period covered by the studied cores reached back to the 18th century. The Pb concentration in the studied profiles varied from 10 to 550 mg kg − 1. The 206 Pb/ 207 Pb ratio varied in the range from 1.154 to 1.194 in the individual parts of the profile. The metallurgy of the Pb ores (206 Pb/ 207 Pb ∼ 1.16), lithogenic Pb (206 Pb/ 207 Pb ∼ 1.2), metallurgical processing of automobile batteries (206 Pb/ 207 Pb ∼ 1.17) and the combustion of coal (206 Pb/ 207 Pb ∼ 1.17-1.19) yield isotopic signatures that determine the isotope compositions of the individual profiles. Deposition rates between 15 mg m − 2 year − 1 at the beginning of the 19th century and 320 mg m − 2 year − 1 in the 1980s were determined in the dated profiles. The increased deposition rates determined on the dated profiles correspond to the increasing production of Pb ores in the Příbram mining area at the turn of the 19th and 20th centuries. The maximum for metallurgical production corresponds to the highest deposition rates recorded in 1960s and 1970s. The current deposition rate of 5-89 mg m − 2 year − 1 Pb is related to erosion of contaminated soils and waste dumps.
Hakite, ideally Cu 10 Hg 2 Sb 4 Se 13 , is a Se-dominant member of the tetrahedrite group occurri... more Hakite, ideally Cu 10 Hg 2 Sb 4 Se 13 , is a Se-dominant member of the tetrahedrite group occurring at only a few localities in the World. A new occurrence of this mineral in the Príbram uranium and base-metal ore district, Central Bohemia, Czech Republic, is reported in this paper. Hakite was found to be locally abundant and was identified in several samples with Se mineralization. Three chemically distinct types of hakite were distinguished based on electron microprobe study, Hg-rich hakite (hakite sensu stricto), Zn-rich hakite and Cd-rich hakite. Hg-hakite dominates among the samples studied. Its average empirical formula based on 29 apfu (n = 54) is (Cu 5.61 Ag 0.39) Σ6.00 Cu 4.00 (Hg 1.61 Zn 0.20 Cu 0.19 Cd 0.15 Fe 0.04) Σ2.19 (Sb 3.85 As 0.28) Σ4.13 (Se 11.55 S 1.14) Σ12.69. Less common is the Zn-hakite, (Cu 5.80 Ag 0.20) Σ6.00 Cu 4.00 (Zn 1.33 Hg 0.42 Cd 0.22 Cu 0.18 Fe 0.01) Σ2.16 (Sb 3.85 As 0.26) Σ4.11 (Se 10.92 S 1.81) Σ12.73 (n = 22), and rare Cd-hakite has an empirical formula (n = 7) of (Cu 5.84 Ag 0.16) Σ6.00 Cu 4.00 (Cd 1.27 Zn 0.60 Cu 0.10 Hg 0.07 Fe 0.02) Σ2.06 (Sb 4.00 As 0.19) Σ4.19 (Se 12.14 S 0.61) Σ12.75. The refined unit cell of Hg-hakite from Príbram, obtained from powder X-ray diffraction data, is a = 10.8783(3) Å with V = 1287.3(1) Å 3 (Z = 4, for the cubic space group I43m). Structure refinement from the precession electron diffraction data collected on the transmission electron microscope (R = 24.4% for 424 observed reflections), confirmed that hakite is isostructural with tetrahedrite. The evolution of hydrothermal fluids, from which Se mineralization formed, suggests a distinct enrichment in sulfur and depletion in selenium over the time span of crystallization.
Weathering of 450 years old mine wastes after silver mining at Geister vein in the Jáchymov ore d... more Weathering of 450 years old mine wastes after silver mining at Geister vein in the Jáchymov ore district (Czech Republic) and migration of uranium were studied. Specific gamma-ray activity of 226 Ra, measured by field gamma-ray spectrometry, varies from 38 Bq/kg (3 ppm eU) to 3816 Bq/kg (309 ppm eU) in the observed area. The most active material forms the top layer of the dump. The gamma-ray activity of the top layer is caused mainly by 226 Ra. Uranium is leached from upper layer and accumula ted in fossil soils beneath. U-micas were studied using X-ray powder diffraction and EDA. The following succession of supergene alteration was found: autunite meta-autunite bassetite oxidized bassetite.
Abstract The costs of construction waste handling, a scarcity of landfill sites, and requirements... more Abstract The costs of construction waste handling, a scarcity of landfill sites, and requirements for sustainable construction have placed recycling of concrete—the most abundant construction material in the world—under scrutiny. Unlike recycling of aggregates, utilization of sub-sieve fractions from recycled concrete has not yet been adopted in the construction industry. In this study, we investigate the possibility of recovering residual anhydrous clinker embedded in grains of stripped mortar within these fines. Different samples of waste concrete were finely ground and studied using microscopy and chemical analyses to assess the amount of residual clinker. Its contribution to hydration processes was measured by calorimetry, and the impact of recycled concrete fines on mechanical properties of cement pastes was tested. The results indicate that residual anhydrous clinker is present in waste concrete and can be recovered by grinding. Replacing Portland cement with the recycled material in pastes led to a significant increase of tensile strength, while deterioration of compressive strength was negligible when the concrete fines contained higher amounts of residual clinker and when the amount of fines did not exceed 30% of Portland cement weight.
The lead (Pb) content and 206 Pb/ 207 Pb ratio were studied in three peat profiles dated by 210 P... more The lead (Pb) content and 206 Pb/ 207 Pb ratio were studied in three peat profiles dated by 210 Pb from the border-area mountains of the Czech Republic and in the tree rings of spruce trees located in their immediate vicinity. Both archives document a similar progress in Pb pollution levels and Pb accumulation in the 1950'se1990's. The deposition rate (DR) of Pb in peat bogs attained maximum values of 40 mg Pb m À2 y À1 in the "Black Triangle" area and 15 mg Pb m À2 y À1 in more distant areas in this period. The Pb isotopic record of both archives from the contaminated area exhibit a similar trend in the presence of the individual sources of Pb, in which Pb derived from combustion of coal predominates. The peat cores in more distant areas document well the effect of automobile Pb in the atmosphere and its substantial reduction after 2000. The two archives differ in individual patterns following from the differences in the rates of formation of their biomass and different means of deposition of Pb in the two archives.
Kavková et al. Tunguska Event-Related Environmental Disturbance FIGURE 1 | (A) The Tunguska regio... more Kavková et al. Tunguska Event-Related Environmental Disturbance FIGURE 1 | (A) The Tunguska region and the study site-Suzdalevo Lake (SUZ). The bold black line shows the border of the TE tree fall area the black cross shows the TE epicenter. The area of the Tunguska State Reserve is shown in grey. (B) Geographical location of Suzdalevo Lake within Russia. (C) Bathymetric map of Suzdalevo Lake. The white cross indicates the position where two sediment cores (SUZ1 and SUZ3) were taken.
<p>Vertical profiles of Tl, Pb and Zn concentrations and T... more <p>Vertical profiles of Tl, Pb and Zn concentrations and Tl and Pb isotopic ratios in a contaminated peatland/fen (Wolbrom, Poland) were studied to address questions regarding (i) potential long-term immobility of Tl in a peat profile, and (ii) a possible link in Tl isotopic signatures between a Tl source and a peat sample. Both prerequisites are required for using peatlands as archives of atmospheric Tl deposition and Tl isotopic ratios as a source proxy. We demonstrate that Tl is an immobile element in peat with a conservative pattern synonymous to that of Pb, and in contrast to Zn. However, the peat Tl record was more affected by geogenic source(s), as inferred from the calculated element enrichments. The finding further implies that Tl was largely absent from the pre-industrial emissions (>~250 years BP). The measured variations in Tl isotopic ratios in respective peat samples suggest a consistency with anthropogenic Tl (ε<sup>205</sup>Tl between ~ -3 and −4), as well as with background Tl isotopic values in the study area (ε<sup>205</sup>Tl between ~0 and −1), in line with detected <sup>206</sup>Pb/<sup>207</sup>Pb ratios (1.16–1.19). Therefore, we propose that peatlands can be used for monitoring trends in Tl deposition and that Tl isotopic ratios can serve to distinguish its origin(s). However, given that the studied fen has a particularly complicated geochemistry (attributed to significant environmental changes in its history), it seems that ombrotrophic peatlands could be better suited for this type of Tl research.</p>
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Groundwater inflows showing notable natural radioactivity have been found at the northern end of ... more Groundwater inflows showing notable natural radioactivity have been found at the northern end of the Holešovice cable tunnel close to the Čimice Grove. This groundwater originates from the Barrandian Neoproterozoic slates of the Blovice accretionary complex, Belt I (Šárka-Zbiroh Belt) at depths approximately 100 meters below the surface, occurring along 50 meter profile of the cable tunnel. Water springs are dispersed in the spring area, with the total discharge of 2 L/s. Groundwater is cold (T ~ 11.1 – 12.3 °C), neutral (pH ~ 6 – 7.48), suboxic to oxic (Eh (ORPH) ~ 177 up to 418 mV), of a hydrochemical type Ca-Mg-HCO3, total mineralization being around 702 mg/L. Radon activity (222Rn) varies between 415 and 1195 Bq/L and radium activity (226Ra) ranges between 0.18 and 5.3 Bq/L. Activities of Rn and Ra are relatively high. Currently, this is the most radioactive water within Prague agglomeration. This water is relatively aggressive as well, causing damage to the concrete lining of t...
Continuous basalt fibres (CBF) - a novel class of man made mineral fibres - possess good thermal ... more Continuous basalt fibres (CBF) - a novel class of man made mineral fibres - possess good thermal and electric insulating properties. CBF (in form of filaments or fabrics) are suitable materials for flame retarding and other thermally loaded applications (eg, fire blocking interliners in ...
Uraniferous bitumens found in black shales from the Permian rocks at Vrchlabí in the Krkonoše Pie... more Uraniferous bitumens found in black shales from the Permian rocks at Vrchlabí in the Krkonoše Piedmont Basin (Czech Republic) were described and characterized petrologically and mineralogically. The Permian sediments originated from weathering products in metasediments and granitoids of the Krkonoše–Jizera and Orlice–Sněžník crystalline complexes. The organic matter contained up to 4.8 wt.% uranium, as uraninite grains. Elements associated with uraninite, such as Pb, Zr, Cu, and As, may have accumulated from epigenetic fluids in layers rich in organic matter during their late diagenesis. The bitumen structures were extremely heterogeneous, a feature attributed to the radiolytic effects of uranium. Amorphous bitumens, alternating with various forms of nodular and corroded bitumen types from multiple generations, were present. Low and highly altered bitumens with weak anisotropy were recognized, together with halo zones, with reflectance up to 4.37%. The halo zones differed in size, b...
The content and the isotopic composition of lead (Pb) were studied in a peat deposit on the ridge... more The content and the isotopic composition of lead (Pb) were studied in a peat deposit on the ridge of the Brdy Hills, in the vicinity of the Příbram metallurgical works, in the Czech Republic. Quadrupole ICP MS was employed to determine the elemental composition and 206 Pb/ 207 Pb and 208 Pb/ 206 Pb isotope ratios. The individual layers were dated using α spectrometric measurement of the 210 Pb activity. The historical time period covered by the studied cores reached back to the 18th century. The Pb concentration in the studied profiles varied from 10 to 550 mg kg − 1. The 206 Pb/ 207 Pb ratio varied in the range from 1.154 to 1.194 in the individual parts of the profile. The metallurgy of the Pb ores (206 Pb/ 207 Pb ∼ 1.16), lithogenic Pb (206 Pb/ 207 Pb ∼ 1.2), metallurgical processing of automobile batteries (206 Pb/ 207 Pb ∼ 1.17) and the combustion of coal (206 Pb/ 207 Pb ∼ 1.17-1.19) yield isotopic signatures that determine the isotope compositions of the individual profiles. Deposition rates between 15 mg m − 2 year − 1 at the beginning of the 19th century and 320 mg m − 2 year − 1 in the 1980s were determined in the dated profiles. The increased deposition rates determined on the dated profiles correspond to the increasing production of Pb ores in the Příbram mining area at the turn of the 19th and 20th centuries. The maximum for metallurgical production corresponds to the highest deposition rates recorded in 1960s and 1970s. The current deposition rate of 5-89 mg m − 2 year − 1 Pb is related to erosion of contaminated soils and waste dumps.
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