Onset of coupled atmosphere-ocean oxygenation 2.3 billion years ago.

The initial rise of molecular oxygen (O2) shortly after the Archaean-Proterozoic transition 2.5 billion years ago was more complex than the single step-change once envisioned. Sulfur mass-independent fractionation records suggest that the rise of atmospheric O2 was oscillatory, with multiple returns to an anoxic state until perhaps 2.2 billion years ago1-3. Yet few constraints exist for contemporaneous marine oxygenation dynamics, precluding a holistic understanding of planetary oxygenation. Here we report thallium (Tl) isotope ratio and redox-sensitive element data for marine shales from the Transvaal Supergroup, South Africa. Synchronous with sulfur isotope evidence of atmospheric oxygenation in the same shales3, we found lower authigenic 205Tl/203Tl ratios indicative of widespread manganese oxide burial on an oxygenated seafloor and higher redox-sensitive element abundances consistent with expanded oxygenated waters. Both signatures disappear when the sulfur isotope data indicate a brief return to an anoxic atmospheric state. Our data connect recently identified atmospheric O2 dynamics on early Earth with the marine realm, marking an important turning point in Earth's redox history away from heterogeneous and highly localized 'oasis'-style oxygenation.

ION Thallos-HTL: a fluorescent thallium indicator that enables cell-selective and localizable thallium flux assays.

Ion channels are essential proteins for all organisms. Electrophysiology is a useful and commonly employed method to study ion channels, however there is a need for operationally simpler, cost-effective and higher throughput techniques to study ion channel functions in their native environments. Fluorescent ion indicators, such as Fluo-4 and Thallos, have been used for decades to study ion channel activity by measuring the flux of ions through channels of interest. In this work, we present ION Thallos-HTL, a thallium indicator that can be localized using HaloTag technology. This novel indicator enables specific labeling of cells and intracellular compartments in live cells and responds to changes in thallium concentration within these environments. We demonstrate the utility of ION Thallos-HTL by conducting a thallium flux assay using high-throughput instrumentation in a mixed cell population where some cells are expressing HaloTag and some are not.

Anthropogenic Forcing of the Baltic Sea Thallium Cycle.

Anthropogenic activities have fundamentally changed the chemistry of the Baltic Sea. According to results reported in this study, not even the thallium (Tl) isotope cycle is immune to these activities. In the anoxic and sulfidic ("euxinic") East Gotland Basin today, Tl and its two stable isotopes are cycled between waters and sediments as predicted based on studies of other redox-stratified basins (e.g., the Black Sea and Cariaco Trench). The Baltic seawater Tl isotope composition (ε205Tl) is, however, higher than predicted based on the results of conservative mixing calculations. Data from a short sediment core from East Gotland Basin demonstrates that this high seawater ε205Tl value originated sometime between about 1940 and 1947 CE, around the same time other prominent anthropogenic signatures begin to appear in the same core. This juxtaposition is unlikely to be coincidental and suggests that human activities in the surrounding area have altered the seawater Tl isotope mass-balance of the Baltic Sea.

Mechanisms of Uptake and Translocation of Thallium in Brassica Vegetables: An X-ray Fluorescence Microspectroscopic Investigation.

Most nonoccupational human exposure to thallium (Tl) occurs via consumption of contaminated food crops. Brassica cultivars are common crops that can accumulate more than 500 µg Tl g-1. Knowledge of Tl uptake and translocation mechanisms in Brassica cultivars is fundamental to developing methods to inhibit Tl uptake or conversely for potential use in phytoremediation of polluted soils. Brassica cultivars (25 in total) were subjected to Tl dosing to screen for Tl accumulation. Seven high Tl-accumulating varieties were selected for follow-up Tl dosing experiments. The highest Tl accumulating Brassica cultivars were analyzed by synchrotron-based micro-X-ray fluorescence to investigate the Tl distribution and synchrotron-based X-ray absorption near-edge structure spectroscopy (XANES) to unravel Tl chemical speciation. The cultivars exhibited different Tl tolerance and accumulation patterns with some reaching up to 8300 µg Tl g-1. The translocation factors for all the cultivars were >1 with Brassica oleracea var. acephala (kale) having the highest translocation factor of 167. In this cultivar, Tl is preferentially localized in the venules toward the apex and along the foliar margins and in minute hot spots in the leaf blade. This study revealed through scanning electron microscopy and X-ray fluorescence analysis that highly Tl-enriched crystals occur in the stoma openings of the leaves. The finding is further validated by XANES spectra that show that Tl(I) dominates in the aqueous as well as in the solid form. The high accumulation of Tl in these Brassica crops has important implications for food safety and results of this study help to understand the mechanisms of Tl uptake and translocation in these crops.

MnFe2O4-biochar decreases bioavailable fractions of thallium in highly acidic soils from pyrite mining area.

The prevalence of toxic element thallium (Tl) in soils is of increasing concern as a hidden hazard in agricultural systems and food chains. In the present work, pure biochar (as a comparison) and jacobsite (MnFe2O4)-biochar composite (MFBC) were evaluated for their immobilization effects in Tl-polluted agricultural soils (Tl: ∼10 mg/kg). Overall, MFBC exhibited an efficient effect on Tl immobilization, and the effect was strengthened with the increase of amendment ratio. After being amended by MFBC for 15 and 30 days, the labile fraction of Tl in soil decreased from 1.55 to 0.97 mg/kg, and from 1.51 to 0.88 mg/kg, respectively. In addition, pH (3.05) of the highly acidic soil increased to a maximum of 3.97 after the immobilization process. Since the weak acid extractable and oxidizable Tl were the preponderantly mitigated fractions and displayed a negative correlation with pH, it can be inferred that pH may serve as one of the most critical factors in regulating the Tl immobilization process in MFBC-amended acidic soils. This study indicated a great potential of jacobsite-biochar amendment in stabilization and immobilization of Tl in highly acidic and Tl-polluted agricultural soils; and it would bring considerable environmental benefit to these Tl-contaminated sites whose occurrence has significantly increased in recent decades near the pyrite or other sulfide ore mining and smelting area elsewhere.

The impact of microbial community structure changes on the migration and release of typical heavy metal (loid)s during the revegetation process of mercury-thallium mining waste slag.

The effect of changes in microbial community structure on the migration and release of toxic heavy metal (loid)s is often ignored in ecological restoration. Here, we investigated a multi-metal (mercury and thallium, Tl) mine waste slag. With particular focus on its strong acidity, poor nutrition, and high toxicity pollution characteristics, we added fish manure and carbonate to the slag as environmental-friendly amendments. On this basis, ryegrass, which is suitable for the remediation of metal waste dumps, was then planted for ecological restoration. We finally explored the influence of changes in microbial community structure on the release of Tl and As in the waste slag during vegetation reconstruction. The results show that the combination of fish manure and carbonate temporarily halted the release of Tl, but subsequently promoted the release of Tl and arsenic (As), which was closely related to changes in the microbial community structure in the waste slag after fish manure and carbonate addition. The main reason for these patterns was that in the early stage of the experiment, Bacillaceae inhibited the release of Tl by secreting extracellular polymeric substances; with increasing time, Actinobacteriota became the dominant bacterium, which promoted the migration and release of Tl by mycelial disintegration of minerals. In addition, the exogenously added organic matter acted as an electron transport medium for reducing microorganisms and thus helped to reduce nitrate or As (Ⅴ) in the substrate, which reduced the redox potential of the waste slag and promoted As release. At the same time, the phylum Firmicutes, including specific dissimilatory As-reducing bacteria that are capable of converting As into a more soluble form, further promoted the release of As. Our findings provide a theoretical basis for guiding the ecological restoration of relevant heavy-metal (loid) mine waste dumps.

Thallium reabsorption via NKCC2 causes severe acute kidney injury with outer medulla-specific calcium crystal casts in rats.

Thallium (Tl) is one of the most toxic heavy metals, associated with accidental poisoning and homicide. It causes acute and chronic systemic diseases, including gastrointestinal and cardiovascular diseases and kidney failure. However, few studies have investigated the mechanism by which Tl induces acute kidney injury (AKI). This study investigated the toxic effects of Tl on the histology and function of rat kidneys using biochemical and histopathological assays after intraperitoneal thallium sulfate administration (30 mg/kg). Five days post-administration, rats exhibited severely compromised kidney function. Low-vacuum scanning electron microscopy revealed excessive calcium (Ca) deposition in the outer medulla of Tl-loaded rats, particularly in the medullary thick ascending limb (mTAL) of the loop of Henle. Tl accumulated in the mTAL, accompanied by mitochondrial dysfunction in this segment. Tl-loaded rats showed reduced expression of kidney transporters and channels responsible for Ca2+ reabsorption in the mTAL. Pre-administration of the Na-K-Cl cotransporter 2 (NKCC2) inhibitor furosemide alleviated Tl accumulation and mitochondrial abnormalities in the mTAL. These findings suggest that Tl nephrotoxicity is associated with preferential Tl reabsorption in the mTAL via NKCC2, leading to mTAL mitochondrial dysfunction and disrupted Ca2+ reabsorption, culminating in mTAL-predominant Ca crystal deposition and AKI. These findings on the mechanism of Tl nephrotoxicity may contribute to the development of novel therapeutic approaches to counter Tl poisoning. Moreover, the observation of characteristic Ca crystal deposition in the outer medulla provides new insights into diagnostic challenges in Tl intoxication.

Tl(I) and Tl(III)-induce genotoxicity, reticulum stress and autophagy in PC12 Adh cells.

Thallium (Tl) and its two cationic species, Tl(I) and Tl(III), are toxic for most living beings. In this work, we investigated the effects of Tl (10-100 µM) on the viability and proliferation capacity of the adherent variant of PC12 cells (PC12 Adh cells). While both Tl(I) and Tl(III) halted cell proliferation from 24 h of incubation, their viability was ~ 90% even after 72 h of treatment. At 24 h, increased levels of γH2AX indicated the presence of DNA double-strand breaks. Simultaneously, increased expression of p53 and its phosphorylation at Ser15 were observed, which were associated with decreased levels of p-AKTSer473 and p-mTORSer2448. At 72 h, the presence of large cytoplasmic vacuoles together with increased autophagy predictor values suggested that Tl may induce autophagy in these cells. This hypothesis was corroborated by images obtained by transmission electron microscopy (TEM) and from the decreased expression at 72 h of incubation of SQSTM-1 and increased LC3ß-II to LC3ß-I ratio. TEM images also showed enlarged ER that, together with the increased expression of IRE1-α from 48 h of incubation, indicated that Tl-induced ER stress preceded autophagy. The inhibition of autophagy flux with chloroquine increased cell mortality, suggesting that autophagy played a cytoprotective role in Tl toxicity in these cells. Together, results indicate that Tl(I) or Tl(III) are genotoxic to PC12 Adh cells which respond to the cations inducing ER stress and cytoprotective autophagy.

Associations between plasma metal/metalloid mixtures and the risk of central obesity: A prospective cohort study of Chinese adults.

Central obesity has increased rapidly over the past decade and posed a substantial disease burden worldwide. Exposure to metals/metalloids has been acknowledged to be involved in the development of central obesity through regulation of cortisol, insulin resistance, and glucocorticoid receptor reduction. Despite the importance, it is lack of prospective study which comprehensively evaluate the relations between multiple metals exposure and central obesity. We explored the prospective associations of plasma metal concentrations with central obesity in a prospective study of the Dongfeng-Tongji cohort. The present study included 2127 participants with a 6.87-year mean follow-up duration. We measured 23 plasma metal/metalloid concentrations at baseline. The associations between metals and incident central obesity were examined utilizing the Cox proportional hazard regression in single and multiple metals models. Additionally, we applied elastic net (ENET), Bayesian kernel machine regression (BKMR), plasma metal score (PMS), and quantile-based g-computation (Qgcomp) models to explore the joint associations of metal mixtures with central obesity. After adjusting potential confounders, we found significant associations of plasma manganese (Mn) and thallium (Tl) concentrations with a higher risk of central obesity, whereas plasma rubidium (Rb) concentration was associated with a lower risk of central obesity both in single and multiple metals models (all FDR <0.05). The ENET and Qqcomp models verified similar metals (Mn, Rb, and Tl) as important predictors for central obesity. The results of both BKMR model and PMS suggested cumulative exposure to metal mixtures was associated with a higher risk of central obesity. Our findings suggested that co-exposure to metals was associated with a higher risk of central obesity. This study expands our knowledge that the management of metals/metalloids exposure may be beneficial for the prevention of new-onset central obesity, which may subsequently alleviate the disease burden of late-life health outcomes.

Association of serum metal levels with type 2 diabetes: A prospective cohort and mediating effects of metabolites analysis in Chinese population.

Several studies have suggested an association between exposure to various metals and the onset of type 2 diabetes (T2D). However, the results vary across different studies. We aimed to investigate the associations between serum metal concentrations and the risk of developing T2D among 8734 participants using a prospective cohort study design. We utilized inductively coupled plasmamass spectrometry (ICP-MS) to assess the serum concentrations of 27 metals. Cox regression was applied to calculate the hazard ratios (HRs) for the associations between serum metal concentrations on the risk of developing T2D. Additionally, 196 incident T2D cases and 208 healthy control participants were randomly selected for serum metabolite measurement using an untargeted metabolomics approach to evaluate the mediating role of serum metabolite in the relationship between serum metal concentrations and the risk of developing T2D with a nested casecontrol study design. In the cohort study, after Bonferroni correction, the serum concentrations of zinc (Zn), mercury (Hg), and thallium (Tl) were positively associated with the risk of developing T2D, whereas the serum concentrations of manganese (Mn), molybdenum (Mo), barium (Ba), lutetium (Lu), and lead (Pb) were negatively associated with the risk of developing T2D. After adding these eight metals, the predictive ability increased significantly compared with that of the traditional clinical model (AUC: 0.791 vs. 0.772, P=8.85×10-5). In the nested casecontrol study, a machine learning analysis revealed that the serum concentrations of 14 out of 1579 detected metabolites were associated with the risk of developing T2D. According to generalized linear regression models, 7 of these metabolites were significantly associated with the serum concentrations of the identified metals. The mediation analysis showed that two metabolites (2-methyl-1,2-dihydrophthalazin-1-one and mestranol) mediated 46.81% and 58.70%, respectively, of the association between the serum Pb concentration and the risk of developing T2D. Our study suggested that serum Mn, Zn, Mo, Ba, Lu, Hg, Tl, and Pb were associated with T2D risk. Two metabolites mediated the associations between the serum Pb concentration and the risk of developing T2D.

Physiology and molecular basis of thallium toxicity and accumulation in Arabidopsis thaliana.

Thallium (Tl) is a non-essential metal mobilized through industrial processes which can lead to it entering the environment and exerting toxic effects. Plants are fundamental components of all ecosystems. Therefore, understanding the impact of Tl on plant growth and development is of great importance for assessing the potential environmental risks of Tl. Here, the responses of Arabidopsis thaliana to Tl were elucidated using physiological, genetic, and transcriptome analyses. Thallium can be absorbed by plant roots and translocated to the aerial parts, accumulating at comparable concentrations throughout plant parts. Genetic evidence supported the regulation of Tl uptake and movement by different molecular compartments within plants. Thallium primarily caused growth inhibition, oxidative stress, leaf chlorosis, and the impairment of K homeostasis. The disturbance of redox balance toward oxidative stress was supported by significant differences in the expression of genes involved in oxidative stress and antioxidant defense under Tl exposure. Reduced GSH levels in cad2-1 mutant rendered plants highly sensitive to Tl, suggesting that GSH has a prominent role in alleviating Tl-triggered oxidative responses. Thallium down-regulation of the expression of LCHII-related genes is believed to be responsible for leaf chlorosis. These findings illuminate some of the mechanisms underlying Tl toxicity at the physiological and molecular levels in plants with an eye toward the future environment management of this heavy metal.

Assessing thallium phycoremediation by applying Anabaena laxa and Nostoc muscorum and exploring its effect on cellular growth, antioxidant, and metabolic profile.

Thallium (Tl), a key element in high-tech industries, is recognized as a priority pollutant by the US EPA and EC. Tl accumulation threatens aquatic ecosystems. Despite its toxicity, little is known about its impact on cyanobacteria. This study explores the biochemical mechanisms of Tl(I) toxicity in cyanobacteria, focusing on physiology, metabolism, oxidative damage, and antioxidant responses. To this end, Anabaena and Nostoc were exposed to 400 µg/L, and 800 µg/L of Tl(I) over seven days. Anabaena showed superior Tl(I) accumulation with 7.8% removal at 400 µg/L and 9.5% at 800 µg/L, while Nostoc removed 2.2% and 7.4%, respectively. Tl(I) exposure significantly reduced the photosynthesis rate and function, more than in Nostoc. It also altered primary metabolism, increasing sugar levels and led to higher amino and fatty acids levels. While Tl(I) induced cellular damage in both species, Anabaena was less affected. Both species enhanced their antioxidant defense systems, with Anabaena showing a 175.6% increase in SOD levels under a high Tl(I) dose. This suggests that Anabaena's robust biosorption and antioxidant systems could be effective for Tl(I) removal. The study improves our understanding of Tl(I) toxicity, tolerance, and phycoremediation in cyanobacteria, aiding future bioremediation strategies.

This study presents novel insights into thallium (Tl) phycoremediation using Anabaena laxa and Nostoc muscorum, crucial for addressing the increasing contamination concerns stemming from high-tech industries. Elucidating the tolerance mechanisms and physiological responses of these cyanobacterial species to Tl(I) exposure. It highlights the potential of Anabaena laxa as an effective bio-remediator, offering a sustainable solution to mitigate Tl(I) environmental impact.

The Impact of Thallium Exposure in Public Health and Molecular Toxicology: A Comprehensive Review.

This review offers a synthesis of the current understanding of the impact of low-dose thallium (Tl) on public health, specifically emphasizing its diverse effects on various populations and organs. The article integrates insights into the cytotoxic effects, genotoxic potential, and molecular mechanisms of thallium in mammalian cells. Thallium, a non-essential heavy metal present in up to 89 different minerals, has garnered attention due to its adverse effects on human health. As technology and metallurgical industries advance, various forms of thallium, including dust, vapor, and wastewater, can contaminate the environment, extending to the surrounding air, water sources, and soil. Moreover, the metal has been identified in beverages, tobacco, and vegetables, highlighting its pervasive presence in a wide array of food sources. Epidemiological findings underscore associations between thallium exposure and critical health aspects such as kidney function, pregnancy outcomes, smoking-related implications, and potential links to autism spectrum disorder. Thallium primarily exerts cellular toxicity on various tissues through mitochondria-mediated oxidative stress and endoplasmic reticulum stress. This synthesis aims to shed light on the intricate web of thallium exposure and its potential implications for public health, emphasizing the need for vigilant consideration of its risks.

Amphichdiral enhancement on singlet oxygen generation and stable thallium immobilization using iron-driven copper oxide.

Thallium (Tl) as a prominent priority contaminant in aquatic environment necessitates rigorous regulation. However, limited horizon devotes the impact of selective oxidation on the process of thallium purification. In this study, selective active radical of singlet oxygen (1O2) was continually generated for Tl(Ⅰ) oxidation accomplished with efficient Tl(Ⅲ) immobilization using iron-driven copper oxide (CuFe)/peroxymonosulfate (PMS). Fe-doping changed the active center of electronic structure for enhancing the catalytic and adsorptive reactivities, and installed magnetism for solid-liquid separation. Rapid reaction rate (0.253 min-1) coupled with vigorous elimination efficiency (98.32%) relied on electrostatic attraction, surface complexation, and H-bond interaction. EPR and XPS analyses demonstrated that the synergistic effects of ≡ Cu(Ⅰ)/≡Cu(Ⅱ) and ≡ Fe(Ⅲ)/≡Fe(Ⅱ) redounded to the sustained generation of 1O2 through the pathway of PMS → •O2- → 1O2, and 1O2 exploited an advantage to selectively oxidize Tl(Ⅰ) to Tl(Ⅲ). 3D isosurface cubic charts revealed that the immobilizing ability of Tl(Ⅲ) hydrate for CuFe was notably superior to that of Tl(Ⅲ) hydrate for CuO and Tl(Ⅰ) hydrate for CuO/CuFe, which further attested surface reactivity promoted stable immobilization form. This work develops the continuous generation of 1O2 and stable immobilization with the goal of efficiently cleansing Tl-containing wastewater.

Selective removal of thallium from water by MnO2-doped magnetic beads: Performance and mechanism study.

Aqueous thallium has posed an increasing threat to environment as human's intensified activities in mining, refining, process and discharge. Remediation on thallium pollution has been of up-most importance to water treatment. In present work, MnO2 and magnetic Fe3O4 have been implanted to sodium alginate (SA) in presence of carboxyl methyl cellulose (CMC), and the resultant beads consisted of SA/CMC/MnO2/Fe3O4 were characterized. The materials were applied to treatment of Tl-contaminated water as adsorbent in lab. The removal results revealed that the adsorption capacity reached 38.8 mg (Tl)·g (beads)-1 and almost 100 % removal efficiency was achieved. The residual Tl was below 0.1 µg·L-1, meeting the discharge standard regulated in China. The kinetic adsorption was better described as a pseudo-second-order and three-step intra-particle diffusion model. Freundlich isotherm was well fitted the experimental data. The absorbent shown an excellent competitive specificity (KTl/M: ∼104!) over common hazardous ions Cu2+, Cd2+, Co2+, Pb2+ and Cr3+, as well as naturally abundant K+ and Na+ (KTl/M: 10-102) in mimic environmental conditions. Regeneration and reusability of the absorbent was also verified by five absorption-desorpotion cycles. XPS results revealed that a redox reaction between Mn4+ with Tl+, and an ion exchange of H+ (-O-Fe) and Tl+ were assumed to be main process for the specific capturing. This study provided an efficient SA/CMC/MnO2/Fe3O4 composite beads that could be a promising adsorbent for Tl-polluted water treatment.

Mitigation of thallium threat in paddy soil and rice plant by application of functional biochar.

Thallium (Tl) is a highly toxic metal, and its contamination in soils entails high risks to human health via food chain. It remains largely unknown of the effects of applying biochar on Tl uptake in paddy systems despite that few studies have shown that biochar exhibits great potential for decreasing Tl bioavailability in soils. Herein, we examined the mitigating effects of the application of biochar (5 and 20 g/kg pristine biochar; 5 and 20 g/kg Fe/Mn-modified biochar) on Tl uptake in paddy soil and rice plant after an entire rice growth period. The results suggested that the application of Fe/Mn-modified biochar (FMBC) considerably mitigated the accumulation of Tl in different tissues of rice plants. Specifically, total Tl content in rice plants treated with FMBC-20 decreased by over 75% compared with control experiment. In addition, the amendment of FMBC in Tl-rich paddy soils can enhance the communities of microorganisms (Actinobacteria and Proteobacteria). Further analysis of the soil microbial symbiosis network revealed that FMBC promotes the living microorganisms to play modular synergistic interactions, which is crucial for FMBC-induced Tl stabilization in soils. All these findings indicated that FMBC is an efficient and environmentally friendly Tl-immobilization alternative material and can be potentially used in the remediation of Tl-contaminated paddy soils and/or cropland.

[Association of metal/metalloids exposure with abnormal liver function among occupational population in a mining area of Hunan Province:a prospective study].

OBJECTIVE: To investigate the association of metals/metalloids exposure with risk of liver disfunction among occupational population in Hunan Province, and to explore the potential dose-response relationship. METHODS: In 2017, a mining area in Hunan Province was chosen as the research site, and eligible workers were recruited as study subjects. General demographic characteristics, levels of 23 metals/metalloids in plasma and urine, and liver function index(total bilirubin(TBIL), alanine amino transferase(ALT), globulin(GLB) and γ-glutamyl transferase(GGT)) were obtained by questionnaire, physical examination and laboratory tests. Participants were followed up in 2018, 2019 and 2020 respectively. Cox proportional risk model was used to evaluate the relationship between metal/metalloids exposure and risk of liver disfunction, and dose-response relationship curves were plotted by using the restricted cubic spline function. RESULTS: A total of 891 employees were recruited in the study, 576(65.0%)were aged ≤45 years, 832(93.4%) were male and 530(59.5%) worked as smelters. After adjusting various factors such as age, gender, BMI, type of work, education, smoking, alcohol consumption, diet, stress, medical history, exercise and tea consumption, positive correlations were found between plasma tungsten(HR=4.90, 95%CI 1.17-20.48) and urinary barium(HR=1.07, 95%CI 1.02-1.12) levels with abnormally elevated TBIL levels. Additionally, a significant association was observed between plasma thallium and the risk of elevated ALT levels(HR=11.15, 95%CI 1.97-63.29). CONCLUSION: Plasma tungsten and thallium, along with barium found in urine, are risk factors for the development of abnormally elevated liver function indices in occupational groups.

[Determination of 24 elements migration in Yixing clay pottery by inductively coupled plasma mass spectrometry].

OBJECTIVE: To establish an analytical method for determining the migration of 24 elements in Yixing clay pottery in 4% acetic acid simulated solution by inductively coupled plasma mass spectrometry. METHODS: Four types of Yixing clay pottery, including Yixing clay teapot, Yixing clay kettle, Yixing clay pot, and Yixing clay electric stew pot, were immersed in 4% acetic acid as a food simulant for testing. The migration amount of 24 elements in the migration solution was determined using inductively coupled plasma mass spectrometry. RESULTS: Lithium, magnesium, aluminum, iron, and barium elements with a mass concentration of 1000 µg/L; Lead, cadmium, total arsenic, chromium, nickel, copper, vanadium, manganese, antimony, tin, zinc, cobalt, molybdenum, silver, beryllium, thallium, titanium, and strontium elements within 100 µg/L there was a linear relationship within, the r value was between 0.998 739 and 0.999 989. Total mercury at 5.0 µg/L, there was a linear relationship within, the r value of 0.995 056. The detection limit of the elements measured by this method was between 0.5 and 45.0 µg/L, the recovery rate was 80.6%-108.9%, and the relative standard deviation was 1.0%-4.8%(n=6). A total of 32 samples of four types of Yixing clay pottery sold on the market, including teapots, boiling kettles, casseroles, and electric stewing pots, were tested. It was found that the migration of 16 elements, including beryllium, titanium, chromium, nickel, cobalt, zinc, silver, cadmium, antimony, total mercury, thallium, tin, copper, total arsenic, molybdenum, and lead, were lower than the quantitative limit. The element with the highest migration volume teapot was aluminum, magnesium, and barium; The kettle was aluminum and magnesium; Casserole was aluminum, magnesium, and lithium; The electric stew pot was aluminum. CONCLUSION: This method is easy to operate and has high accuracy, providing an effective and feasible detection method for the determination and evaluation of element migration in Yixing clay pottery.

Gallium(III)- and Thallium(III)-Encapsulated Polyoxopalladates: Synthesis, Structure, Multinuclear NMR, and Biological Activity Studies.

Three gallium(III)- and thallium(III)-containing polyoxopalladates (POPs) have been synthesized and structurally characterized in the solid state and in solution, namely, the phosphate-capped 12-palladate nanocubes [XPd12O8(PO4)8]13- (X = GaIII, GaPd12P8; X = TlIII, TlPd12P8) and the 23-palladate double-cube [Tl2IIIPd23P14O70(OH)2]20- (Tl2Pd23P14). The cuboid POPs, GaPd12P8 and TlPd12P8, are solution stable as verified by the respective 31P, 71Ga, and 205Tl nuclear magnetic resonance (NMR) spectra. Of prime interest, the spin-spin coupling schemes allowed for an intimate study of the solution behavior of the TlIII-containing POPs via a combination of 31P and 205Tl NMR, including the stoichiometry of the major fragments of Tl2Pd23P14. Moreover, biological studies demonstrated the antitumor and antiviral activity of GaPd12P8 and TlPd12P8, which were validated to be as efficient as cis-platinum against human melanoma and acute promyelocytic leukemia cells. Furthermore, GaPd12P8 and TlPd12P8 exerted inhibitory activity against two herpetic viruses, HSV-2 and HCMV, in a dose-response manner.

Sunlight-Mediated Reductive Transformation of Thallium(III) in Acidic Natural Organic Matter Solutions: Mechanisms and Kinetic Modeling.

Thallium (Tl) redox state determines its speciation and fate in aqueous environments. Despite the high potential of natural organic matter (NOM) providing the reactive groups to complex and reduce Tl(III), the kinetics and mechanisms by which NOM influences the Tl redox transformation have remained insufficiently understood. Here, we studied the reduction kinetics of Tl(III) in acidic Suwannee River fulvic acid (SRFA) solutions under dark and solar-irradiated conditions. Our results show that the thermal Tl(III) reduction occurs by the reactive organic moieties in SRFA, with the electron-donating capacities of SRFA increased with pH and decreased with [SRFA]/[Tl(III)] ratios. Solar irradiation promoted Tl(III) reduction in SRFA solutions as a result of ligand-to-metal charge transfer (LMCT) within the photoactive Tl(III) species as well as an additional reduction process mediated by a photogenerated superoxide. We demonstrated that the formation of Tl(III)-SRFA complexes decreased the reducibility of Tl(III), with the kinetics dependent on the nature of the binding component and SRFA concentrations. A "three ligand class" kinetics model has been developed and satisfactorily describes Tl(III) reduction kinetics over a range of experimental conditions. The insights presented here should assist in understanding and predicting the NOM-mediated speciation and redox cycle of Tl in a sunlit environment.