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.
- Klíčová slova
- Fractionation, Isotope, Mining, Oxide, Soil, Waste,
- MeSH
- hornictví * MeSH
- izotopy analýza MeSH
- látky znečišťující půdu * analýza MeSH
- monitorování životního prostředí * metody MeSH
- půda * chemie MeSH
- thallium * chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Republika Severní Makedonie MeSH
- Názvy látek
- izotopy MeSH
- látky znečišťující půdu * MeSH
- půda * MeSH
- thallium * MeSH
Thallium (Tl) is a highly toxic trace metal, included in the US EPA list of priority pollutants. Even though its toxicity is potentially higher or comparable to Cd or Hg, its environmental impact is largely unknown. Despite its toxicity, only a few recent studies are mapping the impact of recently introduced Tl on soil microbial communities, namely in agricultural systems but no studies focus on its long term effect. To complement the understanding of the impact of Tl on soil, this study aims to describe the influence of extremely high naturally occurring Tl concentration (50 mg/kg of potentially bioavailable Tl) on soil microbial communities. Our investigation concentrated on samples collected at Buus (Erzmatt, Swiss Jura, Switzerland), encompassing forest and meadow soil profiles of the local soil formed on hydrothermally mineralized dolomite rock, which is naturally rich in Tl. The soil profiles showed a significant proportion of potentially bioavailable Tl. Yet, even this high concentration of Tl has a limited impact on the richness of the soil bacterial community. Only the meadow soil samples show a reduced richness compared to control samples. Furthermore, our analysis of geogenic Tl contamination in the region unveiled a surprising finding: compared to other soils of Switzerland and in stark contrast to soils affected by recent mining activities, the structure of the bacterial community in Buus remained relatively unaffected. This observation highlights the unique ability of soil microbial communities to withstand extreme Tl contamination. Our study advances the understanding of Tl's environmental impact and underscores the resilience of soil microbes in the face of severe long-term contamination.
- Klíčová slova
- Bacterial community, Bacterial ecology, Contamination, Diversity, Heavy metals, Thallium,
- MeSH
- Bacteria MeSH
- látky znečišťující půdu * analýza MeSH
- monitorování životního prostředí MeSH
- půda chemie MeSH
- rtuť * analýza MeSH
- stopové prvky * analýza MeSH
- thallium analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Čína MeSH
- Názvy látek
- látky znečišťující půdu * MeSH
- půda MeSH
- rtuť * MeSH
- stopové prvky * MeSH
- thallium MeSH
In this review, a compilation of the current knowledge on stable thallium (Tl) isotopes (205Tl and 203Tl) in specific industrial processes, soils and plants is presented. An overview of the processes that may control Tl concentration and Tl isotope fractionation is compiled, while also overviewing the ability of Tl isotopic ratios to be used as a 'fingerprint' in source apportionment. Thallium isotopic compositions not only depend on their origin, but also on soil processes that may occur over time. One of the most important phases affecting the fractionation of stable Tl isotopes in soils (or sediments) was systematically identified to be specific Mn(III,IV)-oxides (mainly birnessite), due to their potential ability of oxidative Tl sorption, i.e., indicative of redox Tl reactions to be critical controlling factor. It has been established that the Brassica family is a hyperaccumulator of Tl, with clear demonstrations of Tl isotopic fractionation occurring up the translocation pathway. A clear pattern, so far, was observed with Tl isotopic compositions in plants grown on soils that were contaminated and those grown on uncontaminated soils, indicating the importance of the growing medium on Tl uptake, translocation, and isotopic fractionation.
- Klíčová slova
- Hyperaccumulator, Industrial waste, Isotopic fractionation, Mn-oxides, Soil,
- MeSH
- Brassica * MeSH
- izotopy analýza MeSH
- látky znečišťující půdu * analýza MeSH
- půda MeSH
- thallium MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- izotopy MeSH
- látky znečišťující půdu * MeSH
- půda MeSH
- thallium MeSH
Weathering of Tl-containing sulfides in a model (12-week) peat pot trial was studied to better understand their geochemical stability, dissolution kinetics, alteration products and the associated release and mobility of anthropogenic Tl in organic environments. We also present the effect of industrial acid rainwater on sulfide degradation and Tl migration in naturally acidic peat. Sphalerite (ZnS) was much less stable in peat than other Tl-containing sulfides (galena and pyrite), and thus acted as a major phase responsible for Tl mobilization. Furthermore, Tl incongruently leached out over Zn from ZnS, and accumulated considerably more in the peat solutions (≤5 μg Tl/L) and the peat samples (≤0.4 mg Tl/kg) that were subjected to acid rain watering compared to a deionized H2O regime. This finding was in good agreement with the absence of secondary Tl-containing phases, which could potentially control the Tl flux into the peat. The behavior of Tl was not as conservative as Pb throughout the trial, since a higher peat mobility and migration potential of Tl was observed compared to Pb. In conclusion, industrial acid precipitations can significantly affect the stability of ZnS even in acidic peat/organic environments, making it susceptible to enhanced weathering and Tl release in the long term.
- Klíčová slova
- Contamination, Mobility, Organic matter, Peat, Weathering,
- MeSH
- látky znečišťující půdu * analýza MeSH
- monitorování životního prostředí MeSH
- olovo MeSH
- půda MeSH
- sulfidy MeSH
- thallium * analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- látky znečišťující půdu * MeSH
- olovo MeSH
- půda MeSH
- sulfidy MeSH
- thallium * MeSH
In this study, we report combined Tl isotopic and Tl mineralogical and speciation data from a set of Tl-rich sulfide concentrates and technological wastes from hydrometallurgical Zn extraction. We also present the first evaluation of Tl isotopic ratios over a cycle of sulfide processing, from the ore flotation to pyro- and hydrometallurgical stages. The results demonstrate that the prevailing Tl form in all samples is Tl(I), without any preferential incorporation into sulfides or Tl-containing secondary phases, indicating an absence of Tl redox reactions. Although the Tl concentrations varied significantly in the studied samples (~9-280 mg/kg), the overall Tl isotopic variability was small, in the range of -3.1 to -4.4 ± 0.7 (2σ) ε205Tl units. By combining present ε205Tl results with the trends first found for a local roasting plant, it is possible to infer minimum Tl isotopic effects throughout the studied industrial process. As a result, the use of Tl isotopic ratios as a source proxy may be complicated or even impossible in areas with naturally high/extreme Tl background contents. On the other hand, areas with two or more isotopically contrasting Tl sources allow for relatively easy tracing, i.e., in compartments which do not suffer from post-depositional isotopic redistributions.
- Klíčová slova
- Isotopic Fractionation, Metallurgy, Speciation, Waste,
- MeSH
- izotopy analýza MeSH
- látky znečišťující půdu * analýza MeSH
- monitorování životního prostředí MeSH
- sulfidy MeSH
- thallium * analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- izotopy MeSH
- látky znečišťující půdu * MeSH
- sulfidy MeSH
- thallium * MeSH
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 (ε205Tl between ~ -3 and -4), as well as with background Tl isotopic values in the study area (ε205Tl between ~0 and -1), in line with detected 206Pb/207Pb 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.
- Klíčová slova
- Contamination, Deposition, Isotopes, Mobility, Peat,
- MeSH
- hornictví MeSH
- monitorování životního prostředí MeSH
- olovo * MeSH
- půda MeSH
- thallium * analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- olovo * MeSH
- půda MeSH
- thallium * MeSH
We studied the key geochemical and mineralogical factors that could affect the fractionation of stable thallium (Tl) isotopes in soil. A set of grassland soil samples enriched in geogenic Tl in combination with selected Tl-containing mineral materials from the Czech Republic (Kluky) were investigated for this purpose. The results demonstrate significant incorporation of Tl in pedogenic (specific) Mn-oxide, which led to a large accumulation of the heavy 205Tl isotope (∼+14 ε205Tl units), presumably resulting from oxidative Tl sorption. Consequently, we concluded that the Mn-oxide-controlled Tl uptake is the primary cause of the observed 205Tl enrichment in the middle profile zone, at the A/B soil horizon interface, with up to +4 of ε205Tl. Furthermore, our results displayed a clear relationship between the Tl isotopic fractionation degree and the Mn-oxide soil concentration (R2 = 0.6), as derived from the oxalate-extractable data. A combination of soil and mineralogical considerations suggests that 205Tl enrichment in respective soil samples is also partly due to the Tl present in micaceous clay minerals, mainly illite, which is the predominant pedogenic Tl host phase. In line with our previous results, this Tl behavior can be inferred from systematic Mn-oxide degradation and the associated Tl (enriched in 205Tl) cycling in the studied soils and thus, presumably in the redoximorphic soils in general.
- Klíčová slova
- Fractionation, Illite, Isotope, Mn-oxide, Thallium,
- MeSH
- izotopy MeSH
- látky znečišťující půdu analýza MeSH
- půda * MeSH
- thallium analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- izotopy MeSH
- látky znečišťující půdu MeSH
- půda * MeSH
- thallium MeSH
The paper deals with the thallium (Tl) access into the white mustard (Sinapis alba L.). We were comparing two approaches: A - hydroponic, B - semi-hydroponic (artificial soil). The kinetics of Tl plant uptake at different available Tl doses (0.1, 0.05 and 0.01 mg L-1) was tested. It was revealed that the hydroponic arrangement did not accelerate the plant uptake of Tl. The concentration of plant Tl was surprisingly roughly double under the semi-hydroponic (artificial soil) conditions as compared to the hydroponic system; the highest Tl concentrations were detected in stems, proving an important role of plant grown strategy on Tl bioaccessibility. We found that almost independently of the initial dose of Tl the juvenile stadium of the mustard can preserve1-2% of the total Tl pool. Up to 95% of this Tl dose is stored in the shoots. The different strategy of the plant growing may strongly affect the path of Tl incorporation. The total Tl input into the leaf tissue in hydroponics may be from 69% (p = 0.01) explained by parallel assimilation of Ca. In contrast, the Tl entry into the leaf grown on the artificial soil could be limited by Mn path (R2 = 0.91, p = 0.01).
- Klíčová slova
- Artificial soil, Hydroponic, Phytoremediation, Plant physiology, Plant thallium uptake,
- MeSH
- biodegradace MeSH
- hořčice rodu Sinapis * MeSH
- hydroponie MeSH
- látky znečišťující půdu * MeSH
- půda MeSH
- thallium MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- látky znečišťující půdu * MeSH
- půda MeSH
- thallium MeSH
We studied thallium (Tl) isotope fractionation in white mustard grown hydroponically at different Tl doses. Thallium isotope signatures in plants indicated preferential incorporation of the light 203Tl isotope during Tl uptake from the nutrient solution. Negative isotope fractionation was even more pronounced in dependence on how much the available Tl pool decreased. This finding corresponds to the concept of isotope overprinting related to a high contamination level in the growing media (solution or soil). Regarding Tl translocation in plants, we observed a large Tl isotope shift with an enrichment in the heavy 205Tl isotope in the shoots relative to the roots in treatments with low/moderate solution Tl concentrations (0.01/0.05 mg Tl/L), with the corresponding α205/203Tl fractionation factors of ˜1.007 and 1.003, respectively. This finding is probably a consequence of specific (plant) reactions of Tl replacing K in its cycle. The formation of the S-coordinated Tl(I) complexes, potentially affecting both Tl accumulation and Tl isotope fractionation in plants, however, was not proven in our plants, since we did not have indication for that on the basis of X-ray absorption spectroscopy, suggesting that Tl was mainly present as free/hydrated Tl+ ion or chemically bound to O-containing functional groups.
- Klíčová slova
- Isotope fractionation, Isotopes, Plant, Thallium,
- MeSH
- algoritmy MeSH
- biomasa MeSH
- Brassica metabolismus MeSH
- hořčice rodu Brassica metabolismus MeSH
- kořeny rostlin metabolismus MeSH
- kovy metabolismus MeSH
- listy rostlin metabolismus MeSH
- radioaktivní znečišťující látky MeSH
- radioizotopy thallia chemie metabolismus MeSH
- stonky rostlin metabolismus MeSH
- thallium chemie metabolismus MeSH
- výhonky rostlin metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- kovy MeSH
- radioaktivní znečišťující látky MeSH
- radioizotopy thallia MeSH
- thallium MeSH
We studied arid desert soils from Namibia (Rosh Pinah) that were contaminated with up to 7 mg kg-1 of thallium (Tl) via dust emitted from a local flotation tailing dam. Chemical extractions of waste and soil materials indicated that most of the Tl is strongly bound, in accordance with X-ray diffraction and X-ray absorption spectroscopy data that point to the predominant association of Tl with metal sulfides and phyllosilicates. The isotope fractionation factor ε205Tl of the soil samples (from -0.4 to +3.8) shows a positive linear relationship (R2 = 0.62) with 1/Tl, indicative for the mixing of two major Tl pools, presumably anthropogenic Tl and geogenic Tl. The ε205Tl value for the topmost soil samples (∼+3) closely matches the ε205Tl value for post-flotation waste particles with a diameter of <0.05 mm, whereas the bulk flotation waste exhibits a significantly larger ε205Tl value (∼+6). These variations are in accordance with predominant atmospheric transfer of Tl from the tailings to the adjacent soils via fine (dust) particles. The identified minimal Tl alteration in soils indicates that only a small part of the Tl could be potentially released and passively enter the vegetation, local population and/or food chain in the long term. From this viewpoint, Tl does not represent such an important environmental concern as other (abundant) contaminants at the locality. Furthermore, there could be a relevance for other alkaline desert soils, including those where Tl pollution plays a major role.
- Klíčová slova
- Contamination, Mining waste, Soil, Tl isotopes,
- MeSH
- izotopy MeSH
- látky znečišťující půdu analýza MeSH
- monitorování životního prostředí metody MeSH
- potravní řetězec MeSH
- pouštní klima MeSH
- půda chemie MeSH
- thallium analýza MeSH
- znečištění životního prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Namibie MeSH
- Názvy látek
- izotopy MeSH
- látky znečišťující půdu MeSH
- půda MeSH
- thallium MeSH
