Studies have shown that residents living near rare earth mining areas have high concentrations of rare earth elements (REEs) in their hair. However, the adverse effects of REEs on human health have rarely been the focus of epidemiological studies. The goal of this study was to evaluate the relationship between REEs in hair and the risk of hypertension in housewives. We recruited 398 housewives in Shanxi Province, China, consisting of 163 women with hypertension (cases) and 235 healthy women without hypertension (controls). We analyzed 15 REEs (lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), Yttrium (Y), cerium (Ce), praseodymium (Pr), and neodymium (Nd)) and calcium (Ca) accumulated in housewives hair over a period of two years. The results revealed that, with the exception of Eu, concentrations of the REEs in hair were higher in the cases than in the controls. The univariate odds ratios (ORs) of the 14 REEs were >1, and four of the REEs (Dy, Tm, Yb, and Y) also had adjusted ORs > 1. The increasing dose-response trends of the four REEs further indicated the potential for increased hypertension risk. Moreover, the REEs were negatively correlated with Ca content in hair. These results might suggest an antagonistic effect of REEs on Ca in the human body. It was concluded that high intake of REEs might increase the risk of hypertension among housewives.

Both occupational and environmental exposure to asbestos-mineral fibres can be associated with lung diseases. The pathogenic effects are related to the dimension, biopersistence and chemical composition of the fibres. In addition to the major mineral elements, mineral fibres contain trace elements and their content may play a role in fibre toxicity. To shed light on the role of trace elements in asbestos carcinogenesis, knowledge on their concentration in asbestos-mineral fibres is mandatory. It is possible that trace elements play a synergetic factor in the pathogenesis of diseases caused by the inhalation of mineral fibres. In this paper, the concentration levels of trace elements from three chrysotile samples, four amphibole asbestos samples (UICC amosite, UICC anthophyllite, UICC crocidolite and tremolite) and fibrous erionite from Jersey, Nevada (USA) were determined using inductively coupled plasma mass spectrometry (ICP-MS). For all samples, the following trace elements were measured: Li, Be, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Sb, Cs, Ba, La, Pb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, U. Their distribution in the various mineral species is thoroughly discussed.The obtained results indicate that the amount of trace metals such as Mn, Cr, Co, Ni, Cu and Zn is higher in anthophyllite and chrysotile samples, whereas the amount of rare earth elements (REE) is higher in erionite and tremolite samples. The results of this work can be useful to the pathologists and biochemists who use asbestos minerals and fibrous erionite in-vitro studies as positive cyto- and geno-toxic standard references.

Potentially toxic elements (PTEs) are of major concern due to their high persistence and toxicity. Recently, rare earth elements (REEs) concentration in aquatic ecosystems has been increasing due to their application in modern technologies. Thus, this work aimed to study, for the first time, the influence of REEs (lanthanum, cerium, praseodymium, neodymium, europium, gadolinium, terbium, dysprosium and yttrium) and of salinity (10 and 30) on the removal of PTEs (Cd, Cr, Cu, Hg, Ni and Pb) from contaminated waters by living macroalgae (Fucus spiralis, Fucus vesiculosus, Gracilaria sp., Osmundea pinnatifida, Ulva intestinalis and Ulva lactuca). Experiments ran for 168 h, with each macroalga exposed to saline water spiked with the six PTEs and with the six PTEs plus nine REEs (all at 1 μmol L⁻¹) at both salinities. Results showed that all species have high affinity with Hg (90–99% of removal), not being affected neither by salinity changes nor by the presence of other PTEs or REEs. Cd showed the lowest affinity to most macroalgae, with residual concentrations in water varying between 50 and 108 μg L⁻¹, while Pb removal always increased with salinity decline (up to 80% at salinity 10). REEs influence was clearer at salinity 30, and mainly for Pb. No substantial changes were observed in Ni and Hg sorption. For the remaining elements, the effect of REEs varied among algae species. Overall, the results highlight the role of marine macroalgae as living biofilters (particularly U. lactuca), capable of lowering the levels of top priority hazardous substances (particularly Hg) and other PTEs in water, even in the presence of the new emerging contaminants - REEs. Differences in removal efficiency between elements and macroalgae are explained by the contaminant chemistry in water and by macroalgae characteristics.

Ten sediment core samples with lengths ranging from 35 to 100cm were collected in the Baixada Santista region and analyzed to determine As, Br, Co, Cr, Cs, Fe, Rb, Sb, Ta, Th, U, Zn and rare earths (Sc, Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) level concentrations using instrumental neutron activation analysis (INAA). The studied region is located in the southeastern coast of São Paulo State and is comprised of a densely urbanized area, the largest industrial complex of the country, with a predominance of petrochemical and fertilizer plants. It is also home to Brazil’s most important and busiest port. The conclusions found that the As, La, Sm, Ne, Ce, Eu, Hf, Ta, Th, and U elements have a high background level in the region and that Fe and Zn were the main indicators of anthropogenic contribution in the sediments.

Titanium-based nanomaterials co-doped with terbium (Tb) and sulfur (S) were synthesized by sol–gel method via a facile step. Physicochemical properties of the resulting composites were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), X-ray photo-electron spectroscopy (XPS) and UV–Vis diffused reflectance spectroscopy (DRS). Methylene blue (MB) was used as a degradation target for evaluating the photocatalytic performance. The factors which influence the photocatalytic activity were investigated, including calcined temperatures and S doping amount. Tb, S (2 wt%) co-doped TiO₂ composite calcined at 500 °C exhibited the highest photocatalytic activity with a degradation rate of 72.4% in 3 h. The reaction constant was 0.11529, 0.26025, 0.35038 and 0.41462 h⁻¹ for undoped TiO₂, Tb-doped TiO₂, S-doped TiO₂ and Tb, S co-doped TiO₂, respectively. Importantly, the synergistic effect of terbium and sulfur dopants was profoundly discussed. Furthermore, recycling tests and acute toxicity experiments were carried out to confirm the reusability and biosafety of Tb, S co-doped TiO₂.

Until now, rare earth elements (REEs) recycled from the green phosphor of waste fluorescent lamps (FLs), essentially terbium, remain a major challenge. The sulfuric acid effect on leaching efficiency of REEs from phosphor powder (PP) is investigated in this paper. According to a composite central design, experimental leaching study is performed under various parameters (acid concentration, leaching temperature, and time as well as liquid-to-solid ratio (L/S)). A statistical model of experiments and an analysis of variance are studied in order to predict leaching process. The results showed that by decreasing concentration and L/S ratio while increasing leaching time at optimal temperature value permits profitable terbium extraction. Afterwards, the developed statistical model is explored for an optimized response surface methodology. The obtained results were tested experimentally and showed best terbium extraction with 75%. Moreover, 0.01% for the major contaminant, that is calcium, is reached. This low calcium yield may have a further advantage during REE recovery in the downstream. Therefore, resulting solution under optimal conditions is treated with oxalic acid followed by a calcination of the solid precipitate. Finally, 43.57% and 49.38% are produced for terbium and yttrium oxides, respectively.

This study reports the preparation of TiO₂ and CeO₂ doped with different quantities of terbium and discusses the influence of this dopant on the photocatalytic activity of the semiconductors, with respect to the degradation of methylene blue, under ultraviolet and solar radiations. The oxides obtained were characterized by X-ray diffraction, infrared vibrational spectroscopy, diffuse reflectance spectroscopy, scanning electron microscopy, and dispersive energy spectroscopy. The results indicate that the presence of the dopant in TiO₂ favored the formation of the anatase crystalline phase to the detriment of rutile, increased the band gap energy, and decreased the size of the nanoparticles. Doping CeO₂ with Tb resulted in a fluorite-type crystalline structure, reduced band gap, and smaller particle size. The photocatalytic activity decreases as the concentration of terbium increases regardless of the radiation source and nature of the oxide. Furthermore, a better performance was observed for all semiconductors excited by solar radiation in comparison to ultraviolet light. The samples of pure TiO₂ and TiO₂ doped with 0.5 and 1% terbium showed total removal of the dye after less than 120 min of reaction, while the samples of pure CeO₂ and CeO₂ doped with 0.5% terbium showed approximately 80% and 57% of dye removal after 120 min, suggesting that these materials can be promising for the treatment of industrial effluents.

Background, aim and scope The paper presents concentrations of trace elements in blood of homebred animals (cows and sheep) from Southern Serbia (Bujanovac) and the contents of natural and anthropogenic radionuclides and some heavy metals in feed. The region of Southern Serbia was exposed to contamination by depleted uranium ammunition during NATO attacks in 1999 and therefore, is of great concern to environmental pollution and human and animal health. Materials and methods Conventional instrumental and epithermal neutron activation analyses are used to measure trace elements in cow and sheep blood samples collected randomly at six locations in the region of Bujanovac (village of Borovac) in the spring of 2005. Samples of feed (grass and crops: corn, wheat and oats), collected on the same locations (households), are analysed for the contents of radionuclides on an HPGe detector (Ortec, relative efficiency 23%) by standard gamma spectrometry. The content of Hg, Pb and Cd in feed is determined by standard atomic absorption spectrometry on the VarianSpectra220/ThermoSolar GFS97 spectrometer. Results Concentrations of 29 elements (Na, Al (P), Cl, K, Sc, Cr, Mn, Ni, Fe, Co, Zn, Se, As, Br, Sr, Rb, Sb, In, I, Ba, Cs, La, Nd, Eu, Sm, Tb, Hf, Ta and Th) are determined in blood of the examined animals. In feeds, natural ⁴⁰K is found in all of the samples, cosmogenic ⁷Be and fission product ¹³⁷Cs are detected only in the grass samples, while heavy metals Hg, Cd and Pb are found in the range of 0.01-0.02, 0.84-1.15 and 0.74-7.34 mg/kg, respectively. Calculated soil-to-blood transfer factors are in a wide range of 8·10⁻⁶ to 64, as a result of varying significance of the elements in animal metabolism and feeding habits. Discussion The results of trace elements' concentrations in animal blood are in good agreement with available data for K, Ni, Zn, Se and Rb. Higher Br concentrations in animal blood are most probably caused by large biomass burning events during blood sampling. Very low concentration of Fe in cows and sheep confirms the results of previous biochemical studies on animal anaemia in the region. High concentration of As correlates with geochemical peculiarities of the Balkans and is also likely influenced by the use of pesticides in the agricultural production. For some of the elements (La, Nd, Eu, Sm, Tb, Sb, Hf, Ta, Th, In, Ba, Sr, Sc and Cs), there are few or no literature data. Therefore, some of the presented data are significant not only for the country and the region, but on a wider scale. Activities of natural radionuclides in feeds are within the average values reported for the region, while the activities of ²¹⁰Pb and ²³⁵/²³⁸U are below the limit of detection. This is in accordance with previous investigations showing no widespread contamination by depleted uranium in the area. Contents of Hg and Pb in feeds are below the nationally permissible levels, unlike the content of Cd which exceeds it, probably caused by the use of phosphate fertilisers and fossil fuel combustion in the area. Conclusions In general, the concentrations of trace elements in blood of homebred cows and sheep are in good agreement with reference materials, available literature data and the results of previous studies in the area. The exceptions are Fe, As and Br. The contents of natural and anthropogenic radionuclides in feeds are within the expected levels, and there are no signs of contamination by depleted uranium or other fission products. Apart from Cd, there are no signs of pollution by heavy metals in feeds. The highly sensitive method of instrumental neutron activation analysis provides data on the concentration of some elements in animal blood not previously reported for the region and elsewhere. Recommendations and perspectives The presented study is a part of the long term ongoing project on the health risk assessment on animals and humans in the region. The collected data is intended to provide a base for the animal and human risk assessment as well as an estimate of the general pollution status of the environment in the region. Since some of the investigated elements are classified as important trace elements for livestock, the results could also be used to balance and improve the animal diet and thus, improve the growth and reproduction rate.

This study reports the adsorption of five rare earth elements (REEs) (belonging to light (Nd, Eu, Gd), medium (Tb), and heavy (Y) REE group) on montmorillonite-supported zero-valent iron nanoparticles (nZVI-M). Various parameters about REEs adsorption were investigated: the pH value, the adsorption kinetic, the maximum adsorption capacity, and the adsorption isotherm. The temperature (293–313 K) had a limited effect on the final adsorption equilibrium capacity and the analysis of thermodynamic studies suggests it was spontaneous (negative values of ∆Gᵒ) and exothermic (negative values of ∆Hᵒ). The system randomness decreased after adsorption (negative values of ∆Sᵒ). In addition, the values of thermodynamic parameters and the activation energy were strongly dependent on the temperature range because different kinds of REEs participated in the reaction in the form of hydrated ions and followed a randomly and complexly dissociative adsorption mechanism. According to the intraparticle diffusion model analysis, the adsorption of REEs on nZVI-M was dominated by chemisorption and the nano size of nZVI-M reduced the diffusion thickness and the resistance to intraparticle diffusion. Based on the characterization of adsorbent by XPS, the adsorption mechanisms of REEs on nZVI-M were ion exchange and surface complexation.