Rare earth elements
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Acute toxicity of chlorides of rare earth elements has been determined as EC50 for movement inhibition of oligochaeta Tubifex tubifex, EC50(T.t.). There is no statistically significant difference among EC50 values for the rare earth chlorides. Their QSAR is: EC50(T.t.) = 0.0781 ± 0.0058 (mol l-1) (n=14) and log EC50(T.t.) = -1.107, corresponding to the fact that there is also no sigChem. Listy 101, 793-798 (2007) Laboratorní přístroje a postupy 798 nificant difference in the values of their physicochemical properties. The EC50(T.t.) values are comparable with those of, e.g., BaCl2 or CdCl2 classified as toxic compounds. Thus, the EC50(T.t.) indicates the hazard of rare earth salts for aqueous environment as well. The literature search shows that usage and waste of rare earth elements and their compounds are increasing. Several laboratory findings indicate their possible influence on calcium metabolism in organisms.
Due to limited data-describing abilities of mushrooms to accumulate platinum group elements (PGEs) and rare-earth elements (REEs), the aim of this study was to determine, by inductively coupled plasma optical emission spectrometry followed by microwave-assisted sample digestion by nitric acid, the content of these elements in 20 mushroom species (10 above ground and 10 growing on wood), mostly edible, collected near a busy trunk road. The highest content of PGEs in above-ground mushroom species was observed in Lepista gilva and Suillus bovinus fruit bodies (0.38 ± 0.05 and 0.37 ± 0.03 mg kg(-1) DW, respectively), while in mushrooms growing on wood, the highest content was observed in Pleurotus ostreatus (0.35 ± 0.04 mg kg(-1) DW). The mean content of PGEs for both these groups was 0.23 ± 0.08 and 0.26 ± 0.07 mg kg(-1) DW, respectively. The highest content of REEs in Suillus luteus and Tricholoma equestra was 5.03 ± 0.50 and 2.18 ± 0.56 mg kg(-1) DW, respectively, but within mushrooms growing on wood in Ganoderma applanatum fruiting bodies it was 4.19 ± 0.78 mg kg(-1) DW. Mean contents of REEs were 1.39 ± 1.21 and 1.61 ± 0.97 mg kg(-1) DW in above-ground species and species growing on wood, respectively. Generally, the group of mushroom species growing on wood was capable of slightly higher accumulation of both REEs and PGEs. No limits have been established for both the groups until now.
- MeSH
- Agaricales chemie klasifikace růst a vývoj MeSH
- kovy vzácných zemin analýza MeSH
- platina analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Polsko MeSH
Concentrations of uranium, thorium and rare earth elements (REE) in 36 species of ectomycorrhizal (26 samples) and saprobic (25 samples) macrofungi from unpolluted sites with differing bedrock geochemistry were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Analytical results are supported by use of certified reference materials (BCR-670, BCR-667, NIST-1575a) and the reliability of the determination of uranium was verified by epithermal neutron activation analysis (ENAA). It appears that data recently published on these elements are erroneous, in part because of use of an inappropriate analytical method; and in part because of apparent contamination by soil particles resulting in elevated levels of thorium and REE. Macrofungi from unpolluted areas, in general, did not accumulate high levels of the investigated metals. Concentrations of uranium and thorium were generally below 30 and 125 μg kg(-1) (dry weight), respectively. Concentrations of REE in macrofungi did not exceed 360 μg kg(-1) (dry weight) and their distribution more or less followed the trend observed in post-Archean shales and loess.
There is a growing demand for rare earth elements (REEs) due to their use in modern technologies, and this may result in their emission to the environment. This is the first long-term study to monitor the content of REEs in four edible mushroom species. Over 21,900 samples of fruit bodies (sporocarps) of Boletus edulis, Imleria badia, Leccinum scabrum and Macrolepiota procera and their underlying soils, collected between 1974 and 2019 from 42 forest sites in Poland were examined in an attempt to understand the time evolution of the presence of REEs in the environment. In general, I. badia and B. edulis displayed a greater total content of REEs on mg per kg basis than L. scabrum and M. procera. A gradual increase in REEs in the studied mushrooms as well as associated forest soil samples was observed over the monitored period. Both levels were also highly correlated. Regardless of the considered period, human consumption of these mushrooms would not contribute significantly to dietary exposure to REEs. Wild growing mushroom species studied over a long time period may be a good bioindicator of REE migration to the environment.
- MeSH
- Agaricales chemie MeSH
- kovy vzácných zemin analýza MeSH
- látky znečišťující půdu analýza MeSH
- lesy MeSH
- lidé MeSH
- monitorování životního prostředí * MeSH
- půda MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Polsko MeSH
We studied photochemically induced precipitation of rare-earth elements (REEs) in water from a tributary to Plešné Lake and a tributary to Jiřická Pond, Czech Republic. Both tributaries had high concentrations of dissolved organic matter (∼1.8 mmol C L-1). Filtered (0.2 μm) samples were exposed to artificial solar radiation of 350 W m-2 for 48 to 96 h, corresponding to 3 to 6 days of natural solar radiation in summer at the sampling locations. Experiments were performed with altered and unaltered pH ranging from 3.8 to 6.0. The formation of particulate REEs occurred in all exposed samples with the fastest formation observed at the original pH. The formation of particulate metals continued in irradiated samples after the end of irradiation, suggesting that photochemically induced reactions and/or continuing precipitation continue in darkness or in deeper water due to mixing. Results were compared with paleolimnological records in the Plešné Lake sediment. At pH 5.0, the photochemically induced sediment flux was 3509 nmol m-2 y-1 for Ce, corresponding to 42% of the REEs' annual sediment flux in recent sediment layers. Combining the formation rates obtained in the laboratory irradiation experiments and known 1 day incident solar radiation enabled the estimation of a possible REE sediment flux. For Plešné Lake, the photochemically induced formation of particulate REEs explained 10-44% of the REE concentrations in the upper sediment layers. Observed photochemically induced sequestration of REEs into sediments can explain a significant part of the REEs' history in the Holocene sediment.
- MeSH
- chemické látky znečišťující vodu * MeSH
- geologické sedimenty MeSH
- jezera MeSH
- kovy vzácných zemin * MeSH
- monitorování životního prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Technology-critical elements (TCEs) include most rare earth elements (REEs), the platinum group elements (PGEs), and Ga, Ge, In, Nb, Ta, Te, and Tl. Despite increasing recognition of their prolific release into the environment, their soil to plant transfer remains largely unknown. This paper provides an approximation of the potential for plant uptake by calculating bioconcentration factors (BCFs), defined as the concentration in edible vegetable tissues relative to that in cultivation soil. Here data were obtained from an indoor cultivation experiment growing lettuce, chard, and carrot on 22 different European urban soils. Values of BCFs were determined from concentrations of TCEs in vegetable samples after digestion with concentrated HNO3, and from concentrations in soil determined after 1) Aqua Regia digestion and, 2) diluted (0.1 M) HNO3 leaching. For comparison, BCFs were also determined for 5 traditional metal contaminants (TMCs; As, Cd, Cu, Pb, and Zn). The main conclusions of the study were that: 1)BCF values for the REEs were consistently low in the studied vegetables;2)the BCFs for Ga and Nb were low as well;3) the BCFs for Tl were high relative to the other measured TCEs and the traditional metal contaminants; and 4) mean BCF values for the investigated TCEs were generally highest in chard and lowest in carrot. These findings provide initial evidence that there are likely to be real and present soil-plant transfer of TCEs, especially in the case of Tl. Improvements in analytical methods and detection limits will allow this to be further investigated in a wider variety of edible plants so that a risk profile may be developed.
