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Recentní publikace v časopisech s IF > 2

Recent papers in journals with IF > 2 

 

 

Kolaříková I., Švandová J., Přikryl R., Vinšová Jedináková-Křížová, Zeman J. (2009) Mineralogical changes in bentonite barrier within Mock-Up-CZ experiment. Applied Clay Science, in press: doi:10.1016/j.clay.2009.11.011

 IF(2008) = 2.005
Abstract: Mineralogical changes in the bentonite-based barrier of the laboratory Mock-Up-CZ experiment were evaluated by X-ray diffraction. The material of the barrier is a mixture of non-activated bentonite (containing Fe-montmorillonite with Ca2+ exchangeable cation) (85 vol. %), quartz sand (10 vol. %) and graphite (5 vol. %). The barrier has been subjected to thermal stress (up to 90°C) and synthetic "granitic" water for 45months. From 70 analysed samples taken at different depth levels and distances from the source of the heat and/or water, 10 show measurable transformation of original smectites to either mixed illite/smectite structure (3 samples) or to beidellite (7 samples). Formation of mixed illite/smectite structure was restricted to low temperature field (40-50°C) whilst beidellite occurs in zones affected by higher temperature (50-80°C). The low extent of smectite transformation (1-2 wt. %) is due both to relatively short time of the experiment in contrast to the duration of similar processes in nature and also to a limited supply of potassium cations from synthetic water used for hydration. Along with the above mentioned changes, newly formed gypsum bordered by illite aureol was detected in the upper part of the experimental set-up, i.e. in the zone in direct contact to the source of the water. Gypsum formation is interpreted as due to the oxidation of pyrite, a phase available either from the original bentonite where it is common accessory or from the graphite used in the system due to heat transfer. In contrast to non-transformed mixture the several mm wide illitic aureol of gypsum clusters shows a significantly lower ion exchange ability.

  Borovička J., Dunn, C.E., Gryndler M., Mihaljevič M., Jelínek M., Rohovec J., Rohošková M, Řanda Z. (2010): Bioaccumulation of gold in macrofungi and ectomycorrhizae from the vicinity of the Mokrsko gold deposit, Czech Republic. Soil Biology and Biochemistry 42, 83-91.

IF(2008) = 2.926
Abstract: Samples of macrofungi collected in the vicinity of the Mokrsko gold deposit were analyzed for Au by INAA and ICP-MS. Ectomycorrhizal fungi yielded from 0.88 to 564μgkg-1 Au (dry weight) in 79 samples. Saprobic fungi (75 samples) from the same locations yielded significantly higher concentrations: 3-7739μgkg-1 Au (dry weight), with the highest contents in Lycoperdon perlatum. These are the highest recorded concentrations of Au in naturally-occurring fungi/vascular plants. Concentrations of Au in ectomycorrhizae were approximately 4-10 times higher than those in fine roots. It appears that saprobic fungi, namely several terrestrial saprobes of the genera Agaricus and Lycoperdon, are more efficient than ectomycorrhizal fungi at taking up Au, probably assisted by other microbiota and/or by a range of naturally-occurring compounds that have yet to be identified. The present data demonstrate that macrofungi are involved in the biogeochemical cycling of Au.

Přikryl R., Weishauptová Z. (2009): Hierarchical porosity of bentonite-based buffer and its modification due to increased temperature and hydration. Applied Clay Science doi: 10.1016/j.clay.2009.10.005.

 IF(2008) = 2.005

 
Abstract: The use of the hierarchical pore structure in a bentonite-based mixture as a part of a nuclear waste repository's engineering barrier is proposed. The pore structure was observed in an experimental mixture composed of milled Ca-bentonite (85 vol. %), quartz sand (10 vol. %), and graphite (5 vol. %), which had been subjected to long-term (44 months) combined effects of increased temperature (up to 90°C) and hydration during the Mock-Up-CZ experiment. Although there were negligible changes in the mineralogical composition (a slight increase of illite content, and minor conversion of montmorillonite to beidellite), the studied material underwent significant changes in the hierarchical pore structure. The parameters of the pore space were examined by adsorption techniques (CO2, N2), as well as by the intrusion technique (mercury porosimetry). Detectable pore radii ranged from about 0.4 nm to 58 mm (micro-, meso-, macropores, and coarse pores). The observed pore categories were attributed to the presence of solid particles and their arrangement. The smallest pores exhibited a typical radius of 0.65 nm (a range from 0.4 to 1.6 nm), a total specific surface area of 50 m2/g for the initial material. Mesopores showing radii 10-20times higher were found within aggregates of clay mineral particles. Their specific surface area was roughly similar to that of micropores. Simultaneous heating and hydration decreased the specific surface area of the micropores close to the source of heat (i.e. in the direction of increasing temperature). There was a slight increase of their volume in moderately heated areas (50-70°C) and a decrease in both the less heated (30-40°C) and highly heated areas (over 70°C). The same process increased the specific surface area of mesopores by 1-18 %. The maximum increase of this parameter was observed in the samples exposed to a lower temperature (30-40°C). The volume and specific surface area of macropores and coarse pores significantly decreased (by 20 and 40 % respectively) when compared to the pre-experimental material but the typical radius of macropores was increased by a factor of about 2 or 3 in the zone of maximum temperature. This fact contributed to increased hydraulic conductivity observed by Pusch et al. (2008).

Vaněk A., Chrastný V., Komárek M., Galušková I., Drahota P., Grygar T., Tejnecký V., Drábek O. (2010): Thallium dynamics in contrasting light sandy soils - soil vulnerability assessment to anthropogenic contamination. Journal of Hazardous Materials 173, 717-723.

IF(2008) = 2.975 

 
Abstract: The influence of different soil conditions and the presence of LMWOA (Low Molecular Weight Organic Acids) on anthropogenic Tl dynamics were discussed in this study. A shift from the "labile" to the residual fraction during the ageing was identified, indicating Tl incorporation into stable phases (e.g., illite and/or amorphous silicates). The increased water-soluble Tl concentration (1.8-fold, in maximum) after the split application of LMWOA (simulating root exudation) was observed in all soils; partial dissolution of relatively "insoluble" Tl-bearing phases (silicates and eventually oxides) in the presence of LMWOA is suggested. Thermodynamic modeling showed that Tl mobilization in the presence of citric and oxalic acids was indirect and could be attributed to complexation of major elements (Ca, Mg, Al) originating from the dissolution of various soil phases. On the contrary, H+-promoted dissolution by acetic acid was assumed as the predominant mechanism of Tl mobilization. Manganese(III,IV) oxides, illite and probablyamorphous silicates were evaluated as the dominant phases responsible for Tl retention in the soils. In carbonate-rich soils, Tl coprecipitation with the newly formed carbonates seems to be an important factor influencing Tl release. Therefore, we suggest data on CEC, pHZPC and soil mineralogy to be critical for assessment of Tl behavior in soil systems.

Jehlička J., Vítek P., Edwards H.G.M., Heagraves M., Čapoun T. (2009):Rapid outdoor non-destructive detection of organic minerals using a portable Raman spectrometer. Journal of Raman Spectroscopy 40, 1645-1651.

 IF(2008) = 3.526

 
Abstract: Raman spectra of crystalline salts of carboxylic acids-whewellite and mellite, as well as of aromatic mineral idrilite and amorphous fossil resin were recorded using a portable instrument. All spectra were obtained using 785-nm diode excitation. Obtained results document well that portable Raman instruments can be considered as excellent tools for field geological or exobiological applications.

 

Drahota P., Filippi M. (2009): Secondary arsenic minerals in the environment: A review. Environment International 35, 1243-1255.

IF(2008) = 3.516
Abstract: Information on arsenic (As) speciation in solid materials is critical for many environmental studies concerned with As stability and/or mobility in natural As-impacted soils and mining or industrial sites contaminated by As. The investigation of these systems has provided evidence for a number of secondary As minerals that have often played a significant role in As mobility in the solid phase - water system. This paper presents a list of environmentally important secondary As minerals in contaminated soil and waste systems, summarizes the information about their origin, occurrence, environmental stability and thermodynamics, and proposes several important avenues for further investigation.
 

Ettler V., Vrtišková R., Mihaljevič M., Šebek O., Grygar T., Drahota P. (2009): Cadmium, lead and zinc leaching from smelter fly ash in simple organic acids-Simulators of rhizospheric soil solutions. Journal of Hazardous Materials 170, 1264-1268.

IF(2008) = 2.975
Abstract: Emissions from base-metal smelters are responsible for high contamination of the surrounding soils. Fly ash from a secondary Pb smelter was submitted to a batch leaching procedure (0.5-168 h) in 500M solutions of acetic, citric, or oxalic acids to simulate the release of toxic metals (Cd, Pb, Zn) in rhizosphere-like environments. Organic acids increased dissolution of fly ash by a factor of 1.3. Cadmium and Pb formed mobile chloro- and sulphate-complexes, whereas Zn partly present in a citrate (Zn-citrate-) complex is expected to be less mobile due to sorption onto the positively charged surfaces of hydrous ferric oxides (HFO) and organic matter (OM) in acidic soil.

 

Jehlička J., Vítek P., Edwards H.G.M., Heagraves M., Čapoun T. (2009): Fast detection of sulphate minerals (gypsum, anglesite, baryte) by a portable Raman spectrometer. Journal of Raman Spectroscopy 40, 1082-1086.

 IF(2008) = 3.526
Abstract: Well-resolved Raman spectra of gypsum, anglesite and baryte were detected using a portable Raman instrument (Ahura First Defender XL) in the laboratory and outdoor under atmospheric conditions. Spectra were obtained using a 785-nm excitation. The portable spectrometers display generally lower spectral resolution compared with the laboratory confocal instrument but permit the fast, unambiguous detection of minerals under field conditions. Portable Raman instruments can be advocated as excellent tools for field geological, environmental as well as exobiological applications. A miniaturized Raman instrument will be included in the Pasteur analytical package of the ESA ExoMars mission and interesting research applications can now be proposed for in situ field planetary studies. Additionally, portable Raman instruments represent an ideal tool for demonstrating possible applications of Raman spectroscopic techniques outdoor. In geosciences this approach represents a new field which could completely change classical field work.
   

Vítková M., Ettler V., Šebek O., Mihaljevič M., Grygar T., Rohovec J. (2009): The pH-dependent leaching of inorganic contaminants from secondary lead smelter fly ash. Journal of Hazardous Materials 167, 427-433.

IF(2008)= 2.975
Abstract: The leaching behaviour of fly ash (FA) from a secondary Pb smelter was assessed using the pH-static leaching experiment according to prEN 14997 (pH range 3-11) coupled with mineralogical investigation of the leached FA by XRD and Rietveld analyses and thermodynamic modelling using PHREEQC-2. The procedure was performed on fresh FA and FA washed at a cumulative L/S ratio of 60 l/kg to remove readily soluble salts. For both fresh and washed FA, high amounts of inorganic contaminants were released under acidic conditions, exhibiting L-shaped leaching patterns: up to 300 g Pb/kg, 4.5 g Cd/kg, 4 g Zn/kg, 1.05 g As/kg and 70 mg Sb/kg. The washing of soluble salts significantly decreased the leachability of Cd, Zn, As and Sb and increased the release of Pb, especially under acidic conditions. The leaching of fresh FA removed part of primary caracolite and all the KPb2Cl5 and NaCl. The Pb release was controlled by the precipitation of anglesite and PbSO3 under acidic conditions and of laurionite and carbonates (hydrocerussite and phosgenite) under alkaline conditions. In contrast, the washed FA was composed mainly of anglesite and PbSO3, both phases being the main solubility-controlling phases for Pb over the whole studied pH range.
   

Filippi M., Machovič V., Drahota P., Böhmová V. (2009): Raman microspectroscopy as a valuable additional method to X-ray diffraction and electron microscope/microprobe analysis in the study of iron arsenates in environmental samples. Applied Spectroscopy 63, 621-626.

IF(2008) = 2.062

 
Abstract: In this paper, we demonstrate that combined application of X-ray diffraction (XRD), electron microscope/microprobe analysis (EMPA), and Raman microspectroscopy is an available and powerful approach for identification and characterization of iron arsenate minerals in complex environmental samples. Arsenic-rich material from the medieval mining dump close to the Giftkies mine in the Ja´chymov ore district (Czech Republic) has been studied. Scorodite, kankite, amorphous iron arsenate (pitticite), and, to a lesser extent, native sulfur were determined in the studied samples as products of low-temperature arsenopyrite weathering. Scorodite and kanˇ kite form mixed nodules and crusts, which are locally coated by hardened gel-like amorphous pitticite. Pitticite also borders fractures in the mineralized rock fragments in the dump. Native sulfur, in microscopic crystals and grainy aggregates, originates directly in places with dissolved arsenopyrite and forms pseudomorphs. The Raman spectra presented in the paper can serve as comparative data for phase identification in other contaminated areas. New Raman data for the hydroxyl stretching region of scorodite (important bands: 3514, 3427, and 3600 cm1) and the whole Raman spectrum for pitticite (important bands: 472, 831, 884, 2935, 3091, 3213, 3400, and 3533 cm1) are a valuable output of this paper.