Aluminium (Al) speciation is a characteristic that can be used as a tool for describing the soil acidification process. The question that was answered is how tree species (beech vs spruce) and type of soil horizon affect Al speciation. Our hypotesis is that spruce and beech forest vegetation are able to modify the chemical characteristics of organic horizon, hence the content of Al species. Moreover, these characteristics are seasonally dependent. To answer these questions, a detailed chromatographic speciation of Al in forest soils under contrasting tree species was performed. The Jizera Mountains area (Czech Republic) was chosen as a representative mountainous soil ecosystem. A basic forestry survey was performed on the investigated area. Soil and precipitation samples (throughfall, stemflow) were collected under both beech and spruce stands at monthly intervals from April to November during the years 2008-2011. Total aluminium content and Al speciation, pH, and dissolved organic carbon were determined in aqueous soil extracts and in precipitation samples. We found that the most important factors affecting the chemistry of soils, hence content of the Al species, are soil horizons and vegetation cover. pH strongly affects the amount of Al species under both forests. Fermentation (F) and humified (H) organic horizons contain a higher content of water extractable Al and Al(3+) compared to organo-mineral (A) and mineral horizons (B). With increasing soil profile depth, the amount of water extractable Al, Al(3+) and moisture decreases. The prevailing water-extractable species of Al in all studied soils and profiles under both spruce and beech forests were organically bound monovalent Al species. Distinct seasonal variations in organic and mineral soil horizons were found under both spruce and beech forests. Maximum concentrations of water-extractable Al and Al(3+) were determined in the summer, and the lowest in spring.
- MeSH
- buk (rod) MeSH
- hliník analýza chemie MeSH
- koncentrace vodíkových iontů MeSH
- látky znečišťující půdu analýza chemie MeSH
- lesy MeSH
- půda chemie MeSH
- roční období MeSH
- smrk MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Geografické názvy
- Česká republika MeSH
An amorphous manganese oxide (AMO) and a Pb smelter-polluted agricultural soil amended with the AMO and incubated for 2 and 6 months were subjected to a pH-static leaching procedure (pH 3-8) to verify the chemical stabilization effect on metals and metalloids. The AMO stability in pure water was pH-dependent with the highest Mn release at pH 3 (47% dissolved) and the lowest at pH 8 (0.14% dissolved). Secondary rhodochrosite (MnCO3) was formed at the AMO surfaces at pH>5. The AMO dissolved significantly less after 6 months of incubation. Sequential extraction analysis indicated that "labile" fraction of As, Pb and Sb in soil significantly decreased after AMO amendment. The pH-static experiments indicated that no effect on leaching was observed for Cd and Zn after AMO treatments, whereas the leaching of As, Cu, Pb and Sb decreased down to 20%, 35%, 7% and 11% of the control, respectively. The remediation efficiency was more pronounced under acidic conditions and the time of incubation generally led to increased retention of the targeted contaminants. The AMO was found to be a promising agent for the chemical stabilization of polluted soils.
- MeSH
- arsen chemie MeSH
- hutnictví MeSH
- koncentrace vodíkových iontů MeSH
- látky znečišťující půdu chemie MeSH
- nakládání s odpady MeSH
- oxidy chemie MeSH
- průmyslový odpad MeSH
- regenerace a remediace životního prostředí MeSH
- sloučeniny manganu chemie MeSH
- těžké kovy chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The release of hazardous elements from the wastes of high-temperature processes represents a risk to the environment. We focused on the alteration of fly ash (FA) from glassworks collected from an electrostatic filter. FA contains elevated concentrations of Zn and Ba, among other elements. Overtime, small amounts of FA have been emitted from the factory and settled into the surrounding environment (soil). In order to assess the possible risks to the environment, samples of FA were placed in small nylon bags and deposited in 11 different soil horizons (containing diverse vegetation cover such as spruce and beech and also unforested areas). Samples of the FA in bags were exposed in the soils for 1 year. Then, the bags were collected, and the exposed soils in the direct vicinity of the FA bags were sampled. The total concentrations of Zn and Ba in the FA, as well as in the soil samples (original and exposed), were determined by ICP MS. The "mobile fraction" was determined as the exchangeable (acid extractable) fraction of the modified BCR sequential extraction procedure (SEP). The SEP results indicate that Zn and Ba may pose a potential environmental risk. Their concentrations in the first, most mobile, and bioavailable fraction increased in all the exposed soils. The most significant increases were observed in the upper soil horizons (litter and A horizon). The risk to the environment was evaluated on the basis of the Risk Assessment Code.
Metal smelting is often responsible for local contamination of environmental compartments. Dust materials escaping from the smelting facilities not only settle in the soil, but can also have direct effects on populations living close to these operations (by ingestion or inhalation). In this particular study, we investigate dusts from Cu-Co metal smelters in the Zambian Copperbelt, using a combination of mineralogical techniques (XRD, SEM/EDS, and TEM/EDS), in order to understand the solid speciation of the contaminants, as well as their bioaccessibility using in vitro tests in simulated gastric and lung fluids to assess the exposure risk for humans. The leaching of metals was mainly dependent on the contaminant mineralogy. Based on our results, a potential risk can be recognized, particularly from ingestion of the dust, with bioaccessible fractions ranging from 21 to 89% of the total contaminant concentrations. In contrast, relatively low bioaccessible fractions were observed for simulated lung fluid extracts, with values ranging from 0.01% (Pb) up to 16.5% (Co) of total contaminant concentrations. Daily intakes via oral exposure, calculated for an adult (70 kg, ingestion rate 50 mg dust per day), slightly exceeded the tolerable daily intake limits for Co (1.66× for fly ash and 1.19× for slag dust) and occasionally also for Pb (1.49×, fly ash) and As (1.64×, electrostatic precipitator dust). Cobalt has been suggested as the most important pollutant, and the direct pathways of the population's exposures to dust particles in the industrial parts of the Zambian Copperbelt should be further studied in interdisciplinary investigations.
- MeSH
- arsen analýza MeSH
- biologické modely MeSH
- dospělí MeSH
- hodnocení rizik MeSH
- hutnictví * MeSH
- látky znečišťující vzduch analýza MeSH
- lidé MeSH
- monitorování životního prostředí * MeSH
- prach analýza MeSH
- průmysl MeSH
- techniky in vitro MeSH
- těžké kovy analýza MeSH
- velikost částic MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Zambie MeSH
Waste slag which is created during precious metal smelting contains high levels of potentially toxic elements (PTE) which can be mobilised from unconfined deposits into the local environment. This paper examines the extractability of selected PTE (Pb, Zn, Cd, Mn) from slag samples by synthetic solutions designed to replicate those in the environment. Extracting agents were used to replicate potential leaching scenarios which are analogous to natural chemical weathering. Slag was submersed in a rainwater simulation solution (RSS), weak citric acid solution (representing rhizosphere secretions) and control solutions (deionised water) for a one month period with solution analyses made at intervals of 1, 24, 168 and 720 h. In 1 mM citric acid, dissolution of Cd and Zn showed little change with time, although for Zn the initial dissolution was considerable. Lead in citric acid was characterized by overall poor extractability. Mn solubility increased until an equilibrium state occurred within 24 h. The solubility of studied metals in citric acid can be characterized by a short time to equilibrium. RSS proved to be an effective solvent that, unlike citric acid solution, extracted increasing concentrations of Cd, Mn and Zn with time. Solubility of Pb in RSS was again very low. When taken as a proportion of a single 2 M HNO3 extraction which was applied to slag samples, Cd was the element most readily leached into RSS and control samples. In both studied solvents, slag heterogeneity is prominent in the case of Cd and Zn solubility. Contact time with solvent appears to be an important variable for the release of PTE from slag into solution. The purpose of this study was to provide insight into the environmental chemical dissolution of PTE from slag, which causes their enrichment in surrounding soils and surface waters.
- MeSH
- déšť chemie MeSH
- hutnictví MeSH
- kyselina citronová chemie MeSH
- látky znečišťující půdu analýza chemie MeSH
- monitorování životního prostředí MeSH
- rozpouštědla chemie MeSH
- spektrofotometrie atomová MeSH
- stříbro analýza chemie MeSH
- těžké kovy analýza chemie MeSH
- znečištění životního prostředí analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Soils in the vicinity of nonferrous metal smelters are often highly polluted by inorganic contaminants released from particulate emissions. We used a technique with double polyamide experimental bags (1-μm mesh) to study the in situ transformation of fly ash (FA) from a secondary Pb smelter in acidic soil profiles. Between 62 and 66% of the FA dissolved after one year's exposure in the soils, leading to complete dissolution of primary caracolite (Na(3)Pb(2)(SO(4))(3)Cl) and KPb(2)Cl(5), with formation of secondary anglesite (PbSO(4)), minor PbSO(3), and trace carbonates. Release of Pb was pH-dependent, whereas not for Cd and Zn. Significant amounts of metals (mainly Cd and Zn) partitioned into labile soil fractions. The field data agreed with laboratory pH-static leaching tests performed on FA, which was washed before the experiment to remove soluble salts. This indicates that appropriate laboratory leaching can accurately predict FA behavior in real-life scenarios (e.g., exposure in soil).
Powder samples prepared from gasoline (Pt, Pd, Rh, new GN/old GO) and diesel (Pt, new DN/old DO) catalysts and recycled catalyst NIST 2556 were tested using kinetic leaching experiments following 1, 12, 24, 48, 168, 360, 720 and 1440-h interactions with solutions of 20mM citric acid (CA), 20 mM Na(2)P(4)O(7) (NaPyr), 1 g L(-1) NaCl (NaCl), a fulvic acid solution (FA-DOC 50 mg L(-1)) and 20 mM CA at pH 3, 4, 5, 6, 7, 8 and 9. The mobilisation of platinum group elements (PGEs) was fastest in solutions of CA and NaPyr. In the other interactions (NaCl, FA), the release of PGEs was probably followed by immobilisation processes, and the interactions were not found to correspond to the simple release of PGEs into solution. Because of their low concentrations, the individual complexing agents did not have any effect on the speciation of Pd and Pt in the extracts; both metals are present in solution as the complexes Me(OH)(2), Me(OH)(+). Immobilisation can take place through the adsorption of the positively charged hydroxyl complexes or flocculation of fulvic acid, complexing the PGEs on the surface of the extracted catalysts. The calculated normalised bulk released NRi values are similar to the reaction rate highest in the solutions of CA and NaPyr.
Currently standardised leaching tests require grain size reduction, which for large fragments of slags could overestimate the leaching results. To assess the effect of the fine-grained fraction generated by sample crushing, a set of leaching experiments was performed on copper smelting slag from the Zambian Copperbelt: (i) EN 12457-2 batch tests (standardised grain size <4 mm; modified procedure with grain size of 4-0.5 mm simulating exposure of larger fragments on the dumps) and (ii) CEN/TS 14997 pH-static tests (standardised grain size <1 mm simulating the possible wind dispersion scenario near the slag crushing facilities or disposal of fine-grained granulated slag; additional grain sizes <5 mm, 5-0.5 mm and 5-0.5 mm after ultrasonic cleaning). A higher proportion of the fine-grained fraction generally led to greater leaching of Cu, Co and Zn. The metal levels in the leachates under circum-neutral conditions were all below the EU limits for non-hazardous waste. However, at pH 4, the presence of fine dust particles dramatically increased the concentrations of metals in the slag leachates. The greater leachability of Cu and Co from slag particles under acidic conditions suggests a risk of their mobilisation in acidic soils in the Copperbelt area.
- MeSH
- měď chemie toxicita MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The influence of illite and birnessite (δ-MnO(2)) amendments on the retention and bioavailability of Tl in contaminated soils was investigated. The efficiency of both phases was evaluated using Tl uptake by white mustard (Sinapis alba L.), sequential extraction and sorption experiments. The obtained data demonstrate that the application of birnessite can effectively transform Tl from the labile (easily mobilizable) fraction to its reducible form, thus lowering Tl bioavailability in soil and subsequent accumulation by plants. The Mn oxide added to the soils reduced substantially Tl uptake; Tl levels in the plants decreased by up to 50%, compared to the non-amended soil. The effect of illite on the immobilization and uptake of Tl was less pronounced, and in the carbonate-rich Leptosol has not been proved at all, suggesting the importance of bulk soil mineralogy and nature of the soil sorption complex on the behavior of this amendment. Therefore, the general applicability of illite for Tl stabilization in soils seems to be limited and strongly dependent on soil composition. In contrast, the use of birnessite like soil additive might be an efficient and environment-friendly solution for soil systems contaminated with Tl.
Environments in the vicinity of the lead (Pb) smelters are contaminated by emissions containing high concentrations of antimony (Sb) and arsenic (As). Air-pollution-control (APC) residues from bag-type filters from a secondary Pb smelter were subjected to leaching experiments to elucidate the controlling mechanisms of Sb and As release. Kinetic batch leaching tests at a liquid-to-solid (L/S) ratio of 10 L kg(- 1) within the time frame of 720 hours and batch leaching at various L/S ratios (ranging from 1 to 1000 L kg(-1)) were performed. In contrast to other inorganic contaminants (Pb, Cd, Zn), less than 1% of the total Sb and As content was leached from the residues. At a L/S ratio of 10, the As and Sb concentrations in the leachates exceeded the EU limit values for non-hazardous waste (0.2 and 0.07 mg L(-1) ). According to PHREEQC-2 calculations, the concentrations of As and Sb are controlled by the precipitation of complex arsenates and antimonates mainly at low L/S ratios. The washing and related chemical/mineralogical transformation of APC residues was suggested as a technological pre-treatment process before their re-smelting in a blast furnace. The Ferrox-like processing of the resulting contaminated process water/leachate was simulated using the PHREEQC-2 code. Significant reduction was obtained in the concentration of some key contaminants (As, Cu, Pb, Zn) related to sorption on newly formed hydrous ferric oxides, whereas Sb and Cd exhibited only limited attenuation.
- MeSH
- antimon analýza izolace a purifikace MeSH
- arsen analýza izolace a purifikace MeSH
- hutnictví MeSH
- látky znečišťující vzduch analýza izolace a purifikace MeSH
- olovo analýza izolace a purifikace MeSH
- průmyslový odpad prevence a kontrola MeSH
- spalování odpadů MeSH
- těžké kovy analýza izolace a purifikace MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
