Peter Matúš

Utilization of optimized BCR three-step sequential and dilute HCl single extraction procedures for soil-plant metal transfer predictions in contaminated lands.

The prediction of soil metal phytoavailability using the chemical extractions is a conventional approach routinely used in soil testing. The adequacy of such soil tests for this purpose is commonly assessed through a comparison of extraction results with metal contents in relevant plants. In this work, the fractions of selected risk metals (Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Zn) that can be taken up by various plants were obtained by optimized BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and by single 0.5 mol L(-1) HCl extraction. These procedures were validated using five soil and sediment reference materials (SRM 2710, SRM 2711, CRM 483, CRM 701, SRM RTH 912) and applied to significantly different acidified soils for the fractionation of studied metals. The new indicative values of Al, Cd, Cu, Fe, Mn, P, Pb and Zn fractional concentrations for these reference materials were obtained by the dilute HCl single extraction. The influence of various soil genesis, content of essential elements (Ca, Mg, K, P) and different anthropogenic sources of acidification on extraction yields of individual risk metal fractions was investigated. The concentrations of studied elements were determined by atomic spectrometry methods (flame, graphite furnace and hydride generation atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry). It can be concluded that the data of extraction yields from first BCR SEP acid extractable step and soil-plant transfer coefficients can be applied to the prediction of qualitative mobility of selected risk metals in different soil systems.

Free aluminium extraction from various reference materials and acid soils with relation to plant availability

The single extractions with 15 extractants (agents) (H(2)O, KCl, NH(4)Cl, NH(4)F, CaCl(2), BaCl(2), CuCl(2), LaCl(3), Na(2)S(2)O(4), (NH(4))(2)C(2)O(4), Na(4)P(2)O(7), NTA, EDTA, DTPA, HCl), the optimised BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and the solid phase extraction (SPE) by the chelating ion-exchanger Iontosorb Salicyl (cellulose resin containing covalently bound salicylic acid functional groups) were used for the partitioning of Al in very acid soil samples taken from an area influenced by acid mine solutions. The precision, accuracy and repeatibility for all steps of the optimised BCR SEP were checked on the various reference materials (CRM 483 sewage sludge amended soil, CRM BCR 701 freshwater sediment, SRM 2710 and SRM 2711 Montana soils). Also the new indicative values of the optimised BCR SEP fractional Al concentrations were obtained for these reference materials. The aluminium amounts obtained by the used extraction procedures were valuated and discussed from the aspect of the Al concentration in the plants (grass) growing on the same studied soils. The aluminium toxicity indexes (ATI) calculated for the studied soils, the BaCl(2) and acetic acid soil extracts and the grass stems and roots were used for the assessment of the Al toxicity to the plants. The ATI value was defined as the ratio of the nutrient cations (Ca, Mg, K, Na) concentration sum to the Al concentration. The flame atomic absorption spectrometry (LOQ=0.2mgl(-1)) and the inductively coupled plasma optical emission spectrometry (LOQ=0.03mgl(-1)) were used for the aluminium quantification.

Determination of trace amounts of total dissolved cationic aluminium species in environmental samples by solid phase extraction using nanometer-sized titanium dioxide and atomic spectrometry techniques

Nanometer-sized titanium dioxide was used as a solid-phase extractant for the separation and preconcentration of trace amounts of Al(III) prior to its determination by electrothermal atomic absorption spectrometry (ET AAS) and inductively coupled plasma optical emission spectrometry (ICP OES). The optimal conditions for the proposed solid phase extraction (SPE; 50mg TiO(2), 10 min extraction time, pH 6.0, HCl and HNO(3) as eluents) and ET AAS measurement (1500 degrees C pyrolysis and 2600 degrees C atomization temperatures, Mg(NO(3))(2) as matrix modifier) were obtained. The adsorption capacity of TiO(2) was 4.1mg Al g(-1) TiO(2). Two modes of the proposed procedure were compared, (I) batch and elution mode with the elution of Al from TiO(2) phase by nitric or hydrochloric acid, and (II) batch and slurry mode (without elution) with the direct TiO(2) phase-slurry sampling. Finally, the batch and slurry mode of nanometer-sized TiO(2) SPE with slurry ET AAS detection and quantification was preferred and used for the determination of trace amounts of total dissolved cationic Al species in synthetic and natural water samples. The method accuracy was checked by the analysis of lake water CRM TMDA-61 and by the technique of analyte addition (sample spiking). Under the optimal conditions, the calibration curve for batch and slurry TiO(2) SPE with a 10-fold preconcentration was linear up to 40 microg L(-1) Al. The limit of detection (LOD) and the limit of quantification (LOQ) was 0.11 microg L(-1) Al and 0.35 microg L(-1) Al, respectively, with a preconcentration factor of 20 and a relative standard deviation (RSD) lower than 5%.

Ascorbic acid protects Coccomyxa subellipsoidea against metal toxicity through modulation of ROS/NO balance and metal uptake

Impact of exogenous ascorbic acid (AsA, 100μM) on acute metal toxicity (Pb and Hg, 24h of exposure to 100μM) in unicellular green alga Coccomyxa subellipsoidea was studied. Hg (often extensively) depleted amount of pigments, potassium, soluble proteins, endogenous AsA, non-protein thiols and nitric oxide signal but elevated ROS signal and activities of catalase and superoxide dismutase. Responses to Pb application (if any) were less visible with ROS signal being slightly elevated and amount of non-protein thiols being slightly reduced. Exogenous AsA considerably improved mainly Hg-induced damage at the level of oxidative stress and physiological parameters and evoked an increase in nitric oxide signal. Maximum amount of total Hg was almost 4-fold higher than that of Pb (36.5 vs. 9.73mg/g DW) and AsA depleted both total and intracellular accumulation. At the level of ascorbate-related proteins, exogenous AsA suppressed metal-induced expression and activity of MDHAR and APX but not of DHAR, which may indicate a role of DHAR in algal stress tolerance. Our data suggest that given Coccomyxa species is suitable candidate for remediation of Hg or Pb and that ascorbic acid effectively ameliorates metal-induced toxicity without side effects.

Aluminium leaching from red mud by filamentous fungi.

This contribution investigates the efficient and environmentally friendly aluminium leaching from red mud (bauxite residue) by 17 species of filamentous fungi. Bioleaching experiments were examined in batch cultures with the red mud in static, 7-day cultivation. The most efficient fungal strains in aluminium bioleaching were Penicillium crustosum G-140 and Aspergillus niger G-10. The A. niger G-10 strain was capable to extract up to approximately 141 mg·L(-1) of aluminium from 0.2 g dry weight red mud. Chemical leaching with organic acids mixture, prepared according to A. niger G-10 strains respective fungal excretion during cultivation, proved that organic acids significantly contribute to aluminium solubilization from red mud.

Bioaccumulation and biovolatilization of various elements using filamentous fungus Scopulariopsis brevicaulis.

Biovolatilization and bioaccumulation capabilities of different elements by microscopic filamentous fungus Scopulariopsis brevicaulis were observed. Accumulation of As(III), As(V), Se(IV), Se(VI), Sb(III), Sb(V), Te(IV), Te(VI), Hg(II), Tl(I) and Bi(III) by S. brevicaulis was quantified by analysing the amount of elements in biomass of the fungus using ICP AAS. The highest amounts of bioaccumulated metal(loid)s were obtained as follows: Bi(III) > Te(IV) > Hg(II) > Se(IV) > Te(VI) > Sb(III) at different initial contents, with Bi(III) accumulation approximately 87%. The highest percentages of volatilization were found using Hg(II) (50%) and Se(IV) (46·5%); it was also demonstrated with all studied elements. This proved the biovolatilization ability of microscopic fungi under aerobic conditions. The highest removed amount was observed using Hg(II) (95·30%), and more than 80% of Se(IV), Te(IV), Bi(III) and Hg(II) was removed by bioaccumulation and biovolatilization, which implies the possibilities of use of these processes for bioremediations. There were reported significant differences between bioaccumulation and biovolatilization of almost all applied metal(loid)s if valence is mentioned.

Identifying the Origin of Soil Water Repellency at Regional Level Using Multiple Soil Characteristics: The White Carpathians and Myjavska Pahorkatina Upland Case Study

This paper evaluates the relationship between water repellency and multiple characteristics of topsoil samples belonging to seven Reference Soil Groups, taken from the area of the White Carpathians and the Myjavska pahorkatina Upland. In order to quantify water repellency, the Water Drop Penetration Time test and the Molarity of an Ethanol Droplet test were performed on 210 soil samples. The water repellency data were confronted with a number of categorical and numerical soil variables. It was observed that the particular land-use type and the nature of soil parent material, both are related towards detected water repellency of soil samples. All samples taken from the agricultural (tilled) and grassland soils were wettable. On the contrary, all samples which exhibited water repellency, belonged to the group of forest soils, although, not all forest soils were water repellent. Samples which showed considerable repellency were soils developed either on consolidated sedimentary rocks (sandstones, limestone-dolomitic rocks, flysch) or unconsolidated sediments of aeolic or polygenetic origin. On the other hand, the great majority of soils developed on recent alluvial deposits were clearly wettable. Correlation and regression analyses showed that susceptibility of forest topsoil to exhibit water repellency generally increases with increasing sand and organic carbon contents, and with a simultaneous decrease of soil pH value. An interesting observation came out regarding CaCO 3 and water repellency relation. Although certain soils with higher CaCO 3 exhibited water repellency (Rendzic Leptosols and Cambisols), all soils that developed on loose sediments and contained CaCO 3 were wettable.

Gold and silver determination in Waters by SPHERON® Thiol 1000 preconcentration and ETAAS

A reliable procedure for the electrothermal atomic absorption spectrometry (ETAAS) determination of gold and silver in waters at trace level is described. The method is based on prior separation and preconcentration of the metals using a chelating sorbent SPHERON® Thiol 1000 after acidification of water samples (pH < 3) with nitric acid. Optimization of analytical variables during enrichment and ETAAS determination of the metals are discussed. The accuracy of the method is verified by analysis of certified reference materials. The limits of determinations based on 10 σ definition were 0.005 ng cm−3 for Au and 0.02 ng cm−3 for Ag. Precision of studied elements determination expressed by relative standard deviation varied in the range from 2.9 % to 16.4 %.

Evaluation of Various Inorganic and Biological Extraction Techniques Suitability for Soil Mercury Phytoavailable Fraction Assessment

This article evaluates various extraction techniques’ suitability for soil mercury phytoavailable fraction assessment, including DGT method and extraction with microscopic filamentous fungi metabolites, MgCl2, rainwater, and EDTA. After mercury extraction from contaminated soils by these techniques, the obtained data were compared to mercury accumulation by shoots of barley (Hordeum vulgare L.). Comparison of these values showed that DGT method is able to separate soil mercury with the best agreement to total mercury concentration in shoots of barley. However, comparing mercury extraction efficiency of selected techniques to extraction efficiency of barley, statistical significance at 0.05 significance level was proved for fungal Cladosporium sp. and Alternaria alternata metabolites. Our results indicate that these extraction techniques are suitable for risk assessment of mercury phytoavailability in contaminated areas.

Thallium fractionation in polluted environmental samples using a modified BCR three-step sequential extraction procedure and its determination by electrothermal atomic absorption spectrometry

Determination of thallium in polluted environmental samples and their extracts obtained by a modified BCR three-step sequential extraction procedure was used to study thallium distribution and mobility in the monitored polluted area affected by acidification (Šobov, Central Slovakia). The results of fractionation applied to 5 soil certified reference materials and 14 environmental samples show that the vast majority of thallium occurred in the residual fraction. This means that highly toxic thallium is strongly entrapped in the parent rock materials remains immobile and its environmental toxicity is therefore reduced. The limit of detection for thallium in the studied fractions was lower than 0.050 mg kg−1, the precision (RSD) of the ultratrace determination of thallium in the studied fractions was better than 17 % and the accuracy of the used method was verified by analyzing certified reference materials.