Forms Of Thallium Research Articles

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.

Variation in the burden and chemical forms of thallium in non-detoxified tissues of tilapia fish (Oreochromis niloticus) from waterborne exposure

Thallium (Tl) is highly toxic to aquatic ecosystems, but information about its concentration and distribution characteristics in different fish tissues is limited. In this study, juvenile tilapia (Oreochromis niloticus) were exposed to Tl solutions with different sub-lethal concentrations for 28 days, and the Tl concentrations and distribution patterns in the fish non-detoxified tissues (gills, muscle, and bone) were analyzed. The Tl chemical form fractions, Tl-ethanol, Tl–HCl, and Tl-residual, corresponding to easy, moderate, and difficult migration fraction, respectively, in the fish tissues were obtained by sequential extractant approach. The Tl concentrations of different fractions and total burden were determined using graphite furnace atomic absorption spectrophotometry. Exposure-concentration effect determined the Tl burden in the fish tissues. The average Tl-total concentration factors were 360, 447, and 593 in the bone, gills, and muscle, respectively, and the limited variation during the exposure period indicates that tilapia have a strong ability to self-regulate and achieve Tl homeostasis. However, Tl fractions varied in tissues, and the Tl–HCl fraction dominated in the gills (60.1%) and bone (59.0%), switchover Tl-ethanol fraction dominated in the muscle (68.3%). This study has shown that Tl can be easily taken up by fish during 28-days-period and largely distributed in non-detoxified tissues especially muscle, in which concurrent risks of high Tl-total burden and high levels of Tl in the form of easy migration fraction, posing possible risks to public health.

On site separation of inorganic forms of thallium and arsenic in sea water systems followed by ICP-MS determination.

Reduction of Tl(III) and oxidation of As(III), which are unstable speciation forms, start just after sampling as a result of disturbed chemical equilibrium. Separation of inorganic Tl and As species, unchanged, is thus crucial for reliable results of speciation analysis in water systems. Presented here a simple and fast sample pretreatment, based on ion exchange cartridges, which gives the possibility to separate Tl and As species already on the sampling site. Note the reduction of Tl(III) (15%) is in the range of losses typical for standard procedures based on Tl(III) fixation. The use of SCX-3 allows for Tl(III) and SAX for As(III) separation, which are then quantitated in the effluent by ICP-MS. Determination of non-retained species was done after reduction of the sample volume to 2 mL (50-fold preconcentration), which allowed for detection of As concentrations <0.1 ppb and Tl <0.01 ppb. For As, a collision chamber is required. The possibility of direct determination is very important for the forms being in trace amounts in sea water in the vicinity of harbors.

The changes in the chemical forms of thallium, cobalt and manganese with air-drying of soils

ABSTRACT Thallium (Tl) is a highly toxic metal that induces pathological changes in organs. Many Tl-contaminated soils have been reported worldwide due to the releases of Tl from mineral weathering and mining industry. There is, however, limited information related to the dynamics and analysis of Tl in soil, since Tl is one of the emerging soil contaminants. Tl and cobalt (Co) are specifically adsorbed by manganese (Mn) oxide. On the other hand, air-drying of soils causes the dissolution of Mn oxide and the elution of heavy metals such as Co occluded by Mn oxide. Thus, the Mn oxide dissolution with air-drying is expected to affect the chemical forms of Tl with high sorption affinity to Mn oxide. We conducted the sequential extraction method using moist and air-dried soils. Air-drying caused the increases in Mn and Co in the exchangeable and acid soluble fractions, respectively, and the decreases in those in the Mn oxide occluded fraction, which is consistent with previous reports. Our research revealed that the exchangeable Tl increased and sum of the acid-soluble and Mn oxide occluded Tl decreased due to air-drying. The increments in the exchangeable fraction and the decrements in acid-soluble and Mn oxide occluded fractions were almost the same. Consequently, the increase in exchangeable Tl could be attributed to the other two fractions, indicating that soil Tl is sensitive to the soil drying.

Stability of Tl(III) in the context of speciation analysis of thallium in plants.

The paper presents both "good" and "bad" results obtained during speciation analysis of thallium in plant tissues of a hyperaccumulator of this metal. The object was white mustard - Sinapis alba L. In this plant there were found traces of trivalent thallium. The crucial point of this study (especially in the case of so unstable thallium form as Tl(III)) was to prove that the presence of Tl(III) was not caused by the procedure of sample preparation itself, and that the whole analytical method provides reliable results. Choice of the method for conservation of the initial speciation, extraction with the highest efficiency and proving the correctness of the obtained data were the most difficult parts of the presented study. It was found that: both freezing and drying cause significant changes in the speciation of thallium; quantitative analysis could be performed only with fresh tissues of mustard plants; only short-term storage of an extract from fresh plant tissues is possible; the methodology is not the source of thallium (III); only the presence of DTPA can greatly limit the reduction of TI(III) to TI(I) (up to 1-3%); the UV irradiation results in disintegration of TI(III)DTPA in the presence of plant matrix (reduction up to 90%).

TlI and TlIII presence in suspended particulate matter: speciation analysis of thallium in wastewater

Environmental context Thallium occurs in the environment in two oxidation states, with TlIII being 1000-fold more toxic than TlI. We present a fractionation and speciation study of thallium in suspended particulate matter from highly polluted wastewater samples, and elucidate the dominant forms of thallium. Abstract Thallium (Tl) is a toxic element, whose toxicity is affected by its redox state. Compared with TlIII, TlI is thermodynamically more stable and less reactive; therefore in aquatic environments, dissolved thallium is mostly present as TlI. However, TlIII could be 1000 times more toxic than TlI. A combination of a fractionation and a speciation study carried out in highly polluted wastewater samples from a mining area in southern Poland in order to characterise chemical speciation of Tl in physically defined fractions is presented here. Total, particulate and dissolved thallium was determined. A leaching experiment based on forming TlIII complexed with diethylene triamine penta-acetic acid – a TlIII–DTPA complex – was performed in filters containing suspended particulate matter after single (0.45µm) and sequential filtration (15 + 0.45µm) of wastewater samples. This is the first speciation study of Tl carried out in suspended particulate matter. The results obtained indicate that the dominant form of Tl in suspended particulate matter is TlI, but TlIII could be found in suspended particulate matter fractions larger than 0.45µm.

Crystallization and characterization of the thallium form of the Oxytricha nova G-quadruplex

The crystal structure of the Tl+ form of the G-quadruplex formed from the Oxytricha nova telomere sequence, d(G4T4G4), has been solved to 1.55 Å. This G-quadruplex contains five Tl+ ions, three of which are interspersed between adjacent G-quartet planes and one in each of the two thymine loops. The structure displays a high degree of similarity to the K+ crystal structure [Haider et al. (2002), J. Mol. Biol., 320, 189–200], including the number and location of the monovalent cation binding sites. The highly isomorphic nature of the two structures, which contain such a large number of monovalent binding sites (relative to nucleic acid content), verifies the ability of Tl+ to mimic K+ in nucleic acids. Information from this report confirms and extends the assignment of 205Tl resonances from a previous report [Gill et al. (2005), J. Am. Chem. Soc., 127, 16 723–16 732] where 205Tl NMR was used to study monovalent cation binding to this G-quadruplex. The assignment of these resonances provides evidence for the occurrence of conformational dynamics in the thymine loop region that is in slow exchange on the 205Tl timescale.

Thallium: a review of public health and environmental concerns

Thallium (Tl) is a rare but widely dispersed element. All forms of thallium are soluble enough to be toxic to living organisms. Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc and has been responsible for many accidental, occupational, deliberate, and therapeutic poisonings since its discovery in 1861. Its chemical behavior resembles the heavy metals (lead, gold and silver) on the one hand and the alkali metals (K, Rb, Cs) on the other. It occurs almost exclusively in natural waters as monovalent thallous cation. The solubility of thallous compounds is relatively high so that monovalent thallium is readily transported through aqueous routes into the environment. Tl can be transferred from soils to crops readily and accrues in food crops. The fascinating chemistry and high toxicity potential make thallium and its compounds of particular scientific interest and environmental concern. Thallium was detected in base-metal mining effluents. The conventional removal of heavy metals from wastewater has little effect on thallium. In this review, various treatment options and removal technologies are enumerated in order to protect the environment from thallium toxicity.

Evaluation of a sequential extraction procedure for the fractionation of thallium in soils and determination of the content by flame atomic absorption spectrometry

To evaluate the existing forms of thallium in soils, a slightly modified and reliable procedure of sequential extraction was developed based on the method described by Tessier et al. (Anal. Chem., 51, 844–851, 1979) using samples of Andosols to which a certain amount of thallium was added and cultivated with rice seedlings during 4 months under water-logging conditions in a pot experiment. Five different thallium fractions extracted in soils by this procedure were identified and the amount of thallium was determined using the method of Asami et al. (Fresenius J. Anal. Chem., 356, 348–351, 1996). A preliminary study showed that the detection limit of the amount of thallium determined by flame atomic absorption spectrometry (FAAS) was 0.2 mg L−1, The MgCl2 , CH3COONa, and CH3COONH4 extractants exerted significant effects on the extraction of the thallium fractions that were exchangeable and bound to Fe-Mn oxides, but did not affect the extraction of the other thallium fractions, namely the weak acid-soluble fraction, the fraction bound to organic matter and the residual fraction. It was suggested that the chemical behavior of thallium in soils was characterized by ionic and coordination properties, and that soluble thallium added to soil was mainly bound to Fe-Mn oxides. Moreover, the sequential extraction procedure in the present study showed a good recovery ranging from 85 to 101% in relation to the total amount of thallium determined.

High Affinity of Thallium Ions to Copper Hexacyanoferrate Films

High affinity of thallium(I) ions with respect to a copper hexacyanoferrate (CuHCF) film was found. Interaction between the CuHCF film and thallium(I) ions was investigated using the electrochemical quartz crystal microbalance and cyclic voltammetric techniques. In 0.5 M solution, at submillimolar concentrations of Tl(I) ions, the CuHCF film reversibly transforms, during electrochemical experiments, from the potassium into the thallium form. For slightly higher (several millimoles) Tl(I) concentrations, the electrochemical and gravimetric responses prove that the CuHCF film behaves as the thallium form only. Its formal potential calculated from the dependence of the on [Tl(I)], is for 0.28 V more positive than that found for the potassium form. Experimental results obtained suggest that in both cases, potassium(I) and thallium(I) ions, exchange in interstitial positions takes place. Since the ionic radii and the hydration parameters of both ions are similar, we concluded that this high affinity of thallium(I) ions with respect to the CuHCF film, 250-100 times higher than that of potassium(I) ion, results from chemical interactions. In consequence, the solubility product of a thallium analogue of copper hexacyanoferrate is much smaller than that of the potassium form. For different forms they are equal to values): 37.8 46.3 and 17.2 © 2001 The Electrochemical Society. All rights reserved.

Thallium Speciation in the Great Lakes

An ion-exchange separation technique followed by analysis with atomic absorption spectroscopy was used to study the chemical forms and distribution of thallium in Lakes Michigan, Huron, and Erie. The dominant thallium form found in water samples analyzed was the oxidized Tl(III) which comprised 68 ± 6% of the total dissolved thallium, contrary to thermodynamic prediction that Tl(I) is favored in natural waters. A significant proportion of Tl(III) may be in colloidal form. No definite spatial (horizontal or vertical) pattern was found in the distribution of total dissolved thallium in the water columns of Lakes Michigan, Huron, and Erie. An overall decline of thallium concentration from Lake Michigan to Lake Erie was observed which may be related to rapid scavenging removal from the water column.

Thallium speciation in river waters with Chelex-100 resin

A Chelex-100 resin separation technique followed by analysis with atomic absorption spectroscopy was evaluated for the study of thallium speciation in river waters. The detection limit for the method was 1.0 ng/l for both Tl(I) and Tl(III). Analysis of synthetic solutions consistently yielded >90% recovery of these two thallium forms with negligible cross contamination. Water samples from selected stations in polluted Huron River and Raisin River in Michigan were analyzed. Average dissolved thallium concentrations were found to be 21 ng/l for Huron River and 26 ng/l for Raisin River. The dominant thallium form found in these rivers was oxidized Tl(III) and the proportion of Tl(III) to the total dissolved thallium ranged from 43 to 73% and averaged of 66% in water samples analyzed. A significant proportion of Tl(III) may also be in colloidal form.

Fractionation and spectrophotometric determination of thallium with N,N ′-diphenylbenzamidine, brilliant green and cetylpyridinium chloride

A spectrophotometric method for the determination of inorganic chemical species of thallium i.e.Tl(I), Tl(III) and total Tl at trace level in industrial waste waters, effluents and surface water of the city and neighbouring cities is described. The method is based on the extraction of chlorothallate(III) complex in the presence of cetylpyridinium chloride (CPC) at 0.5–4.5 M HCl with N,N’-diphenylbenzamidine (DPBA) in toluene and subsequent colour reaction of the extract with brilliant green (BG). The molar absorptivity of the Tl(III)-Cl−–CP+–DPBA–BG+ complex in toluene is 1.82x105 Lmol−1 cm−1 at 640 nm. The standard deviation and relative standard deviation of the method (n=10) were found to be 0.007 ppm Tl and 1.3% of the mean absorbance, respectively. The detection limit, defined as the concentration causing more absorbance than twice the standard deviation of 10 replicate measurements of the blank solutionis 5 μg L−1 Tl in water. For effluent samples the concentration ranges of Tl(I), Tl(III) and total Tl were found to be 24.5–49.0, 30.6–36.7 and 55.1–85.7 μg L−1, respectively. While for surface waters these ranges were 39.2–108.1, 19.6–58.2 and 58.8–166.3 μg L−1 respectively. The concentration of these chemical forms of thallium for the waste water samples were found to be 97.9, 49.0 and 146.9 μg L−1, respectively. These data were validated by comparison with standard methods and the AAS method.

Accumulated forms of thallium and cadmium inLemna minor. II. Relationship between duration of exposure and metal-protein binding

AbstractGel filtration chromatography (with Sephadex G25, G50 and G100) was used to separate the different forms of thallium (Tl) and cadmium (Cd) in the cytosol fraction of Lemna minor and to examine the influence of the duration of metal exposure on the speciation of the two elements. A major proportion of Cd in the soluble phase was found to be bound to three groups of proteinaceous and polypeptide fractions; two of these, the high molecular weight protein fraction (Mr > 150,000) and the low polypeptide sized moieties of about Mr 1,500 or less were constitutive entities, whereas the intermediate sized fraction (Mr 7,000 - 8,000) could only be detected in plants previously exposed to Cd. After 12 days of exposure to Cd this fraction accounted for the greatest part of the bound Cd in Lemna tissues. Extending the period of exposure from 18 hours to 12 days resulted in a shift in the distribution of Cd between the low and intermediate fractions. Evidence for Tl-protein binding was limited and confined to t...

Accumulated forms of thallium and cadmium inLemna minor. I. Distribution in aqueous soluble and insoluble fractions

The distribution and chemical forms of thallium (Tl) and cadmium (Cd) in Lemna minor have been investigated using extractants of different polarity, enzyme digestion and ultrafiltration and chromatographic methods. Over 80% of Tl and 60% of Cd taken up by the plant was found in aqueous soluble forms. Water was more efficient than ethanol in extracting both elements; about 30% of bound Cd was released by dilute HCI treatment and Cd was mainly bound to pectins and proteins in the cell wall fractions but only a small proportion of Tl was associated with these components. In the aqueous soluble extracts a sizeable proportion of Cd was complexed with soluble moieties, including proteins; whereas Tl seems to be mainly present in the free ionic form.

Ionic and molecular diffusion and the order-disorder phase transition in the thallium form of natrolite

The thallium form of the narrow-pore zeolite natrolite has been studied with the aid of NMR spectroscopy, scanning calorimetry, and x-ray powder diffraction analysis. A phase transition accompanied by an abrupt change in the mobility of the TI + ions and H=O molecules has been discovered at T = 252 K. The transition may be regarded as "melting" of the aqueous and cation sublattices in the channels of the zeolite skeleton.

The absorption of thallium by plants: A comparison of the uptake of thallium(I) and Thallium(III) by excised barley roots ( hordeum vulgare c.v. maris mink.)

In an aqueous environment thallium exhibits two common oxidation states, thallium(I) and thallium(III) [1]. The Tl + cation has a similar ionic radius to K + and it is known to mimic it in biological systems [2], however relatively little is known about the biological significance of Tl 3+. Accordingly the uptake of thallium supplied initially in both of these ▪ ▪ oxidation states to excised roots [3] has been investigated. The uptake of both forms of thallium increased as expected with both time and applied concentration, but a significant difference was noted in the overall levels of accumulation with Tl + concentrations in the root tissue reaching ten times those found for Tl + under similar conditions. The uptake of Tl + was found to be affected by temperature, with the uptake increasing with temperature over the range 0–30 °C, but showed inhibition thereafter. The uptake of Tl 3+ was unaffected by changes in temperature. Figure 1. The uptake of Tl + was severely diminished by several common metabolic inhibitors, particularly by vanadate which is recognised as an inhibitor of the Na +/K + ATPases. Tl 3+ uptake was unaffected. Desorption studies showed that Tl + could not be removed from the root tissue, suggesting that it had entered the cell, but Tl 3+ was easily removed by cation exchange, suggesting that it was confined to the extracellular space. Overall the results suggest a process of active uptake for Tl + but passive uptake for Te 3+.

Biochemical studies of current environmental levels of trace elements: Cyclotron production of radiothallium and its use for metabolic investigations on laboratory animals

Carrier-free201+202Tl have been produced in the cyclotron by (p, xn) reactions on mercury targets and used as a trcer for thallium in metallobiochemistry of heavy metal pollution. The separation of201+202Tl radioisotopes from Hg involved a solvent extraction method leading to labelled univalent Tl(I) ions. This radioactive solution was used to prepare different201+202Tl labelled compounds such as inorganic Tl(III) ions and organic dimethylthallium. Quality controls have been applied directly on the different radioactive solutions immediately before their administrations to rats in order to ensure that thallium had the chemical form expected. A summary of the main results concerning different aspects of the metabolic investigations on rats such as absorption, retention, excretion, transplacental transport and influence of the different chemical forms of thallium on its metabolism is also reported.