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1.
Environ Monit Assess ; 192(2): 124, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31960198

RESUMO

Investigation on the behavior of elements in the soil is important both in exploration and environmental geochemistry studies. Rare earth elements (REEs) are the most useful among all trace elements. REE studies have shown that they have important applications in igneous, sedimentary, and metamorphic petrology. This work aims to investigate the relationship of these elements with one another and the behavior of the major oxides and trace elements with REEs. Soil samples were obtained from the alteration site possibly related to mineralization and were analyzed for major oxides, trace elements, and REEs. The relationships between the major oxide-trace element/heavy metal and REE were investigated by statistical methods, such as descriptive statistics, correlation coefficient, and principle component analysis. According to the correlation coefficient matrix, light REEs (LREEs) showed weak to moderate negative correlation with MgO and MnO and moderately positive correlation with SiO2 and K2O. No association was detected between the heavy REEs (HREEs) and the main oxides, but a strong positive correlation with LREEs was observed. For the trace elements, LREE showed a weak positive correlation with Ba and Sn and moderate to strong positive correlation with As, Hf, Nb, Rb, Ta, Th, U, W, and Zr. They also displayed weak to moderate correlation with Sc, Co, Zn, Ni, and V. HREE showed weak to moderate positive correlation with Ni, Cs, Ga, Hf, Th, Zr, As, and LREE. Although REEs exhibited no direct correlation with Au and Ag, they showed a good correlation with some trace elements that are related to hydrothermally altered products. This study showed that REEs can also be used in exploration and environmental geochemistry studies by exploiting the relationship between REEs and other trace/heavy metal elements.


Assuntos
Metais Terras Raras/análise , Poluentes do Solo/análise , Oligoelementos/análise , Monitoramento Ambiental/métodos , Metais Pesados/análise , Compostos Orgânicos , Óxidos/análise , Dióxido de Silício/análise , Solo
2.
Ecotoxicol Environ Saf ; 190: 110138, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31901809

RESUMO

New leaching agents could lead to a reduction in ammonia nitrogen pollution and the supplementation of soil nutrients during in-situ mining. They could also result in the release of even more toxic heavy metals, which has an impact on the environment as well as human health. In this study, column leaching experiments were used to simulate in-situ leaching, and the leaching behavior and fractional changes of lead in weathered crust elution-deposited rare earth ore by different leaching agents were studied. The experimental results showed that the amount of lead that was leached followed the order of CLA (60% CaCl2 + 25% NH4Cl + 15% MgSO4) > (NH4)2SO4 > MgSO4. The lead leaching process was comprised of both an acceleration and deceleration stage that followed the first order kinetic model. The amount of Pb when using compound agent was the greatest most likely because of the presence of Cl-. The soil heavy metal morphology test showed that the three leaching agents primarily leached acid extractable lead, and the compound leaching agent leached the greatest amount of acid extractable Pb, which mainly due to the presence of NH4Cl. The reducible fraction was enriched in the direction of migration of the leachate, which was due to the presence of SO42-. These results indicate that the introduction of leaching agents during the mining process pose a greater risk for the release of heavy metals and provide a theoretical basis for the prevention and remediation of heavy metal pollution in mining areas where new leaching agents were used.


Assuntos
Chumbo/análise , Metais Terras Raras/análise , Poluentes do Solo/análise , Metais Pesados/análise , Mineração , Solo , Tempo (Meteorologia)
3.
Chemosphere ; 242: 125142, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31669987

RESUMO

Rare earth elements (REEs) are widely used in various fields, and their accumulation has been reported to pose environmental risks. Most studies confirmed the damage of excessive REE exposure to individual plants; however, little attention has been given to their effects on plant populations. A positive interaction indicates a mutually beneficial relationship between two populations, which is beneficial to the survival and growth of the populations. However, it remains unknown whether exogenous REEs affect the positive interactions between populations. This study investigated the effects of exogenous lanthanum(III) [La(III)] exposure on the positive interaction between soybean (Glycine max L.) and wheat (Triticum aestivum L.) populations by their modules. At normal nutrient level (½-strength Hoagland), the inhibition of excessive La(III) on population modules decreased with increasing population density. Decreases of 39.26 to 1.05% for soybean and 41.45 to 2.41% for wheat indicated the inhibition of La(III) on the positive interaction of both populations weakened with increasing population density. At low nutrient level (»-strength Hoagland), the inhibition of excessive La(III) on population modules increased with increasing population density. Decreases of 5.82-57.14% for soybean and 4.22-59.04% for wheat indicated the inhibition of La(III) on the positive interaction of both population was strengthened with increasing population density. In summary, the inhibitory effects of exogenous La(III) exposure on the positive interaction between populations vary with both nutrient level and population density. This is a new factor that needs to be considered when evaluating the safety risks of REEs in the environment.


Assuntos
Exposição Ambiental/estatística & dados numéricos , Lantânio/metabolismo , Poluentes do Solo/metabolismo , Lantânio/análise , Metais Terras Raras/análise , Poluentes do Solo/análise , Soja/fisiologia , Triticum/fisiologia
4.
Sci Total Environ ; 698: 134282, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505361

RESUMO

Rare earth elements (REEs) are emergent contaminants in aquatic ecosystems in parallel with their growing use in science, technology, and industry. In this study we measured the concentration of 16 REEs in freshwater marcobenthic invertebrates from 6 watercourses in northeast Italy to determine their potential use as ecological tracers of REEs in aquatic ecosystems. The total REE concentration at the sampling sites followed this order: site 6 (7.05 mg Kg-1) > site 3 (5.76 mg Kg-1) > site 4 (3.58 mg Kg-1) > site 1 (3.0 mg Kg-1) > site 5 (2.36 mg Kg-1) > site 2 (1.95 mg Kg-1). There were no significant differences in REE concentrations across the six samplings sites (Kruskal Wallis test, p = 0.1773), but two (site 3 and 6) had higher amount of REEs and were classified with the ecological status "Moderate" sensu Water Framework Directive since affected by anthropogenic activities. Light REE were always greater than heavy REE concentrations at all six sites. A positive correlation was observed between certain REEs (La, Ce, Gd) and the density of genera Caenis and Baetis (Ehemeroptera, collector-gatherers) (ρS range 0.795-0.812), suggesting that non-predatory macrobenthic invertebrates accumulate more REEs than predatory organisms and that the intake of sediment is the most effective route of assimilation.


Assuntos
Monitoramento Ambiental/métodos , Invertebrados/química , Metais Terras Raras/análise , Poluentes Químicos da Água/análise , Animais , Água Doce , Itália
5.
Environ Sci Pollut Res Int ; 26(34): 34854-34872, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31655982

RESUMO

Acid mine drainage is one of the main environmental hazards to ecosystems worldwide and it is directly related to mining activities. In Ecuador, such acidic-metallic waters are drained to rivers without treatment. In this research, we tested a laboratory combined (Ca-Mg) Dispersed Alkaline Substrate (DAS) system as an alternative to remediate acid drainage from the Zaruma-Portovelo gold mining site, at El Oro, Ecuador. The system worked at low and high flow hydraulic rates during a period of 8 months, without signs of saturation.. Analysis of physico-chemical parameters and water composition (ICP-OES, ICP-MS) demonstrated that treatment effectively increased water pH and promoted the retention of about 80% of Fe, Al, Mn and Cu. Under acid conditions As, Cr and Pb concentrations decreased with Fe and possible precipitation of jarosite and schwertmannite. However, the homogeneous depletion of Cr at pH above 6 could be related to ferrihydrite or directly with Cr (OH)3 precipitation. After DAS-Ca, sulphate, phosphate and rare earth elements (REE) concentrations decreased to 1912, 0.85 and 0.07 mg/L respectively, while DAS-Mg contributed to form a complex model of minor carbonate and phosphate phases as main sink of REE. DAS-Mg also promoted the retention of most divalent metals at pH values over seven. Thus, this low cost treatment could avoid environmental pollution and international conflicts. Anyway, further investigations are needed to obtain higher Zn retention values. Graphical abstract.


Assuntos
Monitoramento Ambiental , Recuperação e Remediação Ambiental/métodos , Mineração , Modelos Químicos , Ácidos/análise , Ecossistema , Equador , Compostos Férricos , Compostos de Ferro , Metais Terras Raras/análise , Minerais/análise , Rios/química , Sulfatos , Poluentes Químicos da Água/análise
6.
Artigo em Inglês | MEDLINE | ID: mdl-31652627

RESUMO

Rare earth elements (REEs), known as "industrial vitamins", are widely used in medical treatment, industry, agriculture, etc. However, with the increasing demand for REEs, excess REEs, such as gadolinium (Gd), are considered micropollutants in the environment. In this paper, the distributions of dissolved REEs were analyzed in three small streams, in order to determine the extent and occurrence of Gd anomalies. The shale-normalized REE patterns in the three streams were less smooth with heavy REEs higher than light REEs, for a weak reaction of the heavy REE complexes. A negative Ce (cerium) anomaly and positive samarium (Sm) and europium (Eu) anomalies were observed in the three streams and the negative Ce anomaly was affected by the pH of the alkaline rivers. However, a positive Gd anomaly was found in only a typical urban small stream, Jinzhong. With a population of approximately 60,000, Jinzhong runs by a hospital and through wastewater treatment plants (WWTPs). The concentrations of Gd in Jinzhong ranged from 1.54 to 86.65 ng/L with high anthropogenic Gd proportions (63.64%-98.07%). Anthropogenic Gd showed significant seasonal variations and distinct spatial disparities from upstream to downstream, and it was associated with certain ions such as Cl-. Anthropogenic Gd could be attributed to gadopentetic acid (Gd-DTPA), which is used in magnetic resonance imaging (MRI) in hospitals. This type of Gd was shown to be correlated with municipal wastewater. Due to the high stability and low particulate reactivity in water, anthropogenic Gd has great potential to serve as a tracer to prove the presence of medical wastewater.


Assuntos
Metais Terras Raras/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Rios/química , Águas Residuárias
7.
Chemosphere ; 237: 124477, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31394438

RESUMO

In this work we present a completely new dataset of Rare Earth Element (REE) distribution and fractionation in the groundwater and sediments of the world's largest populated river island-Majuli, located in the Brahmaputra River, India. Groundwater (n = 9) and borehole sediments (n = 23) of different depths were collected randomly and analyzed for REEs using inductively coupled plasma mass spectrometry (ICP-MS). Multivariate statistical techniques were applied to determine interrelationships among different REEs. Both water and sediments exhibit a higher content of light rare earth elements (LREEs) than heavy rare earth elements (HREEs), implying that source rock composition primarily controls the REE signatures of these river sediments, largely owing to variations in levels of chlorite and monazite, which are more abundant in bottom river sediments of the Brahmaputra. However, lower LREE/HREE ratios in groundwater samples (8.42-14.48) compared to sediments (8.9-52.6) suggest less dissolved phase mobilization of LREE during weathering and transport. Hierarchical cluster analysis showed more consistent clustering in sediment compared to water and clear demarcations of MREE, HREE and LREE were observed in the sediments. The primitive mantle-normalized REE patterns of borehole sediments were similar to the upper continental crust (UCC) and the compositions of average Himalayan rocks. LREE enrichment compared to HREE suggest dominance of a felsic source. However, a La/V versus Th/Yb plot suggests a small contribution from the mafic source component. The sediments show high Th/Sc (>1 of UCC) and high Zr/Sc. A Eu/Eu* verses GdN/YbN plot suggests that the dominant source with Upper crustal composition has undergone multiple recycling.


Assuntos
Monitoramento Ambiental , Água Subterrânea/química , Metais Terras Raras/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Sedimentos Geológicos/química , Índia , Ilhas , Rios/química , Tempo (Meteorologia)
8.
Chemosphere ; 237: 124442, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31369900

RESUMO

Present studies facilitated testing the hypothesis that sediment fraction <20 µm contains different amounts of REEs. The potentially bioavailable rare earth elements (REEs) were determined in the following fractions of the surface sediments of the Vistula River: <5 µm, 5-10 µm, 10-20 µm, and total <20 µm. The attempt was made to fractionate the sediment by self-adjustable split-flow transport-thin fractionation channel operating in the full depletion mode (SPLITT-FFD-SA), which is a new concept and so far unused method for such purposes. All three fractions were separated in the expected particle size ranges. The collected fractions were analyzed with the laser diffraction particle size analyzer and the inductively coupled plasma - mass spectrometer (ICP-MS) to determine the size and the elemental composition. ∑REEs in the Vistula sediments declined from 123.41, through 112.59 to 95.22 mg kg-1 in fractions: 10-20 µm, 5-10 µm, <5 µm, respectively. Eleven, out of sixteen REEs, showed statistically significant declining trend in REEs content, with decreasing particle sizes of sediment fractions. Particularly exceptional was Er, whose content in <5 µm fraction was by 12-20% higher than in larger size fractions. Rare earth elements of the Vistula sediments are considerably enriched in the light rare earth elements (LREEs) relative to the heavy rare earth elements (HREEs), with the LREEs/HREEs ratio declining from 4.01 (10-20 µm) to 3.599 (<5 µm). The sequence of mass weighted REEs content in <20 µm size fraction was as follows: Ce > La > Nd > Y > Sc > Pr > Sm > Gd > Dy > Er > Yb > Eu > Tb > Ho > Tm > Lu.


Assuntos
Sedimentos Geológicos/química , Metais Terras Raras/análise , Rios/química , Peso Molecular , Tamanho da Partícula
9.
J Sci Food Agric ; 99(14): 6509-6514, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31321773

RESUMO

BACKGROUND: Rare earth elements (REEs) have been used for the identification of the geographical origins of an increasing number of foods. This study analyzed the effects of geographical origin, harvest season, variety, and their interactions on REEs in tea leaves to investigate whether REEs were suitable for geographical identification of tea leaves. Tea leaves of different varieties and the corresponding soils were collected in different seasons from different areas of China. The concentrations of 14 REEs in tea leaves and soils were determined, and then analyzed with one-way analysis of variance (ANOVA), multi-way ANOVA, correlation analysis, and linear discriminant analysis. RESULTS: All factors significantly affected the contents of REEs in tea leaves. The concentrations of REEs in tea leaves were related to those in provenance soils. However, the concentrations of most REEs in tea leaves were primarily affected by the harvest season. CONCLUSION: Seasonal variations should be considered when REE fingerprinting is applied for the identification of tea for authentication purposes. © 2019 Society of Chemical Industry.


Assuntos
Camellia sinensis/química , Metais Terras Raras/análise , Folhas de Planta/química , Camellia sinensis/classificação , China , Análise Discriminante , Geografia , Folhas de Planta/classificação , Estações do Ano
10.
Environ Monit Assess ; 191(8): 514, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31346771

RESUMO

Despite the rare earth elements (REEs) being considered as emerging contaminants, their natural values and possible anthropogenic enrichments in soils have not been studied well in Brazil. The intensive use of conditioners and fertilizers in agricultural frontiers from Brazilian Cerrado can increase the concentration of REE in soils of the region. In this context, the objectives of this study were to determine the natural content and establish quality reference values (QRV) for REEs in soils of a watershed from Brazilian Cerrado composed of sedimentary rocks and to evaluate the influence of agricultural cultivation and the spatial variability of these elements. Thirty and twenty-six composite soil samples were collected under native vegetation and soybean cultivation, respectively. The background concentrations followed the order (mg kg-1) Ce > Nd > La > Pr > Sm > Yb > Er > Eu > Dy. The QRVs established were as follows (mg kg-1): La (1.76), Ce (5.20), Pr (0.74), Nd (1.35), Sm (0.38), Eu (0.06), Dy (0.15), Er (0.12), and Yb (0.14). Lantanium, Ce, and Er exhibited strong spatial dependence, while Eu, Dy, and Yb showed weak or total absence of spatial dependence. The spherical model was most suitable for the spatial characteristics of REEs. The parent material, mainly characterized by soils derived from sedimentary rocks (i.e., sandstone), was the primordial source of REEs for soils and that there was no or little effect of agricultural practices on these levels. Our data reinforced the need for geochemical mapping at the watershed scale, since they are important conservation units.


Assuntos
Monitoramento Ambiental , Metais Terras Raras/análise , Poluentes do Solo/análise , Agricultura , Brasil , Solo/química
11.
Chemosphere ; 234: 81-88, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31203044

RESUMO

Over recent decades the Aral Sea has faced a major human-driven regression leading to environmental, economic and health impacts. Previous research has indicated that its region may be highly polluted yet there is little recent data to assess the scale or nature of the pollution. The present study investigated the concentration of elements for which the World Health Organization (WHO) has established guideline levels (Al, As, B, Ba, Cd, Cr, Cu, Ni, Pb, Sb) as well as 16 rare-earth elements (Ce, Eu, Er, Gd, La, Nd, Pr, Sc, Sm, Dy, Ho, Lu, Tb, Tm, Y, Yb) in the Small Aral Sea (SAS) and its inflow, the Syr Darya River (SDR). The latter displayed increased levels of Al (mean 851 µg L-1), As (35.8 µg L-1), Cd (2.8 µg L-1), Pb (10.1 µg L-1) and U (4.9 µg L-1), exceeding the guideline limits at selected sites. In the SAS these limits were exceeded at certain locations in the case of As and U. The total mean concentration of REEs in the SDR and SAS amounted to 22.6 and 61.7 µg L-1, respectively, with Pr, Ce and Nd constituting the greatest share. The concentrations of B, Ba Cr, Cu, Se and Ni were below the WHO guideline levels at all studied sites while Sb and Hg were always below detection limits. This research provides an updated status on the levels of contamination of the surface waters in the ecological disaster zone of the Aral Sea in Kazakhstan.


Assuntos
Poluição Ambiental/análise , Metais Terras Raras/análise , Rios/química , Oligoelementos/análise , Humanos , Cazaquistão , Metais Terras Raras/toxicidade , Oceanos e Mares , Oligoelementos/toxicidade
12.
Mar Pollut Bull ; 144: 79-91, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31180009

RESUMO

To exploit the resolving ability of rare earth element and yttrium (REY) in resuspension binary mixing model, and discover potential new REY-related resuspension proxy, this preliminary research studied the geochemical signature of REY in different Jiaozhou Bay samples including surficial/core sediments and settling trap-collected particles. Close quantitative relation for bulk concentration in particles, sediments and fine-grained fraction of major river sediments around the Yellow Sea, approved the priority contribution of catchment detrital materials. Moreover, common characteristics occurred for compartment-specific partitioning REY signatures in six operated-defined fractions, and multiple REY normalization pattern indexes (i.e. Y/Ho divergence, and Ce/Eu anomalies). All constrain the application of REY in resuspension discrimination of marginal shallow seas. However, linearity with different slopes and intercepts were plotted for the MREE bulge index versus HREE/LREE figure in reducible amorphous Fe-oxides fraction, which could provide new discrimination perceptions.


Assuntos
Baías/química , Monitoramento Ambiental/métodos , Metais Terras Raras/análise , Poluentes Químicos da Água/análise , Ítrio/análise , China , Sedimentos Geológicos , Oceanos e Mares , Rios/química
13.
Appl Radiat Isot ; 151: 171-181, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31200192

RESUMO

The present study was conducted to study the compositional trends of rare earth elements (REEs), Th, and U in marine sediment samples in terms of distribution patterns, anomalies, and indicator ratios. For this purpose, a total of 32 marine sediment samples were collected from 12 coastal areas of the Egyptian Red Sea and analyzed using instrumental neutron activation (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) analytical techniques. The analyses investigated 14 REEs, Th, and U. The results revealed that the contents of REE, light REE (LREE), and heavy REE (HREE) are 47.6, 38.7, and 8.3 mg/kg, respectively, whereas the concentration of Th and U is determined as 2.15 and 2.23 mg/kg, respectively. Indicator ratios were calculated, and inter-correlation elements with Th and U were constructed. Multivariate statistics were implemented on the data and GIS technology to construct the distribution patterns of REE, Th, and U along the Egyptian coast of the Red Sea. The obtained results were compared with the corresponding values published in literature to show a good matching. There is a significant enrichment of LREE relative to HREE, a reduced ratio of Th/U, a weak positive anomaly of Eu/Eu*, and a slight positive Ce anomaly is noticed. Among the 12 studied areas, one area, Sharm El-Bahari, located in the middle of the coast, shows peak values of REE, Th, and U relative to the other areas. However, it still shows a good agreement with the results published in the literature.


Assuntos
Sedimentos Geológicos/química , Metais Terras Raras/análise , Oceanos e Mares , Poluentes Químicos da Água/análise , Poluentes Radioativos da Água/análise , Egito , Monitoramento Ambiental/métodos , Sistemas de Informação Geográfica
14.
Appl Radiat Isot ; 151: 116-123, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31174051

RESUMO

A study was carried out to determine the concentrations of rare earth elements (REEs) in Linggi river sediments collected from 113 sampling locations. The sediment analysis was performed by Neutron activation analysis (NAA) and Inductively coupled plasma - mass spectrometry (ICP-MS). The results of Linggi river sediment were normalized to "recent" reference shale values. The means of total concentrations of REEs (ΣREE), light REEs (ΣLREE) and heavy REEs (ΣHREE) in Linggi sediment were 241.2, 219.2, and 22.0 mg/kg, respectively, which indicates enrichment compared to ΣREE, ΣLREE and ΣHREE reference shale values. Results obtained from enrichment factors (EF) show no enrichment to moderate enrichment of Linggi sediments, indicating the sources of REEs pollution originated from natural and land-based activities. A similar pattern was observed by comparing the REEs values of Linggi sediments to other references shale values. Ce (δCe) and Eu (δEu) anomalies indicate Linggi sediments showed positive anomaly of Ce whilst negative anomaly of Eu.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Terras Raras/análise , Poluentes Radioativos da Água/análise , Malásia , Análise de Ativação de Nêutrons
15.
Environ Sci Pollut Res Int ; 26(19): 19897-19905, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31090011

RESUMO

Due to the increasing demand of metals by industry and the limited availability of natural resources, the secondary supply of these elements from discarded products, such as waste electrical and electronic equipment (WEEE), is an important strategy for pursuing a sustainable development. Nevertheless, the complex and heterogeneous composition of this waste stream stands as one of the main drawbacks in the definition of innovative recovery processes. This study investigated the recovery potential of a multi-step leaching process to extract the strategic metals, namely precious metals and rare earth elements (REEs), from the dust produced during the industrial shredding treatment of WEEE. Using a first double-oxidative step with sulfuric acid, most rare earth elements contained in the dust were dissolved at high percentages. Moreover, around 50% of gold was extracted in a second leaching step using 0.25 M thiourea, in a solid to liquid ratio of 0.2 g/70 mL, at 600 rpm. In this regard, the optimum operating conditions were studied by a 23 full factorial design. Experimental results address the definition of a novel approach, pursuing the recovery of resources of great industrial interest from the residues originating from WEEE mechanical treatments typically performed at large scale. As this dust fraction is not sent for recovery but currently disposed, the proposed recycling strategy promotes the diversion of waste from landfill while reducing the need for virgin materials via lower-impact metallurgical processes.


Assuntos
Poeira/análise , Resíduo Eletrônico/análise , Metalurgia , Metais Terras Raras/análise , Reciclagem/métodos , Metalurgia/métodos
16.
Sci Total Environ ; 678: 627-631, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31078853

RESUMO

Rare earth elements (REEs), also called lanthanides, are emerging contaminants worldwide, due to their unique physical and chemical characteristics that make them essential in a variety of industrial applications. However, there is still a gap in the knowledge of occurrence and accumulation of REEs in biota, and no investigations have yet been performed in penguin feathers, which have already been widely utilized as a non-invasive tool for the biomonitoring of trace elements. The concentrations of 16 REEs were investigated in a colony of Humboldt penguins (Spheniscus humboldti) housed at the Acquario di Cattolica (Italy). Multielement determination of REEs was performed by an Inductively Coupled Plasma-Mass Spectrometer after a microwave digestion of feathers. As this colony lives indoors in a controlled environment, it was the ideal choice for studying lanthanide occurrence in penguin feathers. Since there is a strict link between metal levels in feathers and the diet of penguins, their food (capelin) was also tested for REEs. Chondrite normalized values revealed the same pattern for REEs in feathers and fish, but REE concentrations were an order of magnitude higher in penguin feathers, demonstrating the suitability of this tissue as a bioindicator of REEs.


Assuntos
Biomarcadores Ambientais , Metais Terras Raras/análise , Spheniscidae/metabolismo , Animais , Animais de Zoológico/metabolismo , Plumas/química , Feminino , Masculino , Metais Terras Raras/metabolismo
17.
Environ Int ; 128: 279-291, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31071591

RESUMO

Rare earth elements (REY) are the lanthanide elements (Z = 57-71), which have an ever-growing occurrence in present-day industries, agriculture, and modern life. Consequently, environmental concentrations are expected to increase accordingly as a result of intensified utilization. Soils are an important sink for REY, yet little research has been conducted concerning activity, inputs, and lability in soil systems. This study evaluated the REY (lanthanides + yttrium) sorption and partition coefficients (Kd) in two broadly representative natural soils (A horizon), with contrasting mineralogy and organic character, formed under distinct environmental conditions: an Oxisol from Brazil and a Mollisol from the USA. Batch reactions of soils suspended in a background electrolyte solution of 5 µmoles kg-1 of Ca(NO3)2 at 1:100 solid to solution were reacted with 80 µmoles kg-1 REY added individually and in multi-REY competitive systems to evaluated adsorption after 3 h and 72 h over a wide pH range (from ca. 2 to 8). Results showed sorption was similar for all REY within each soil type when examined at the natural measured soil pH; Mollisol pH 6.85, Oxisol pH 4.35. However, REY sorption (by Kd) was nearly two-fold greater in the Mollisol compared to the Oxisol for the single REY experiments. Multi-REY competitive sorption reactions showed a decrease in Kd for both soils at 3 and 72 h, and to a greater extent for the Mollisol, indicating soil type had a strong effect on the sorption affinity of each REY. It was also observed that REY sorption increased from low to high pH (pH 2-8) in the Oxisol, and increased with pH from 2 up to the point zero charge (PZC) in the Mollisol, then stabilized. The varying REY Kd values from these two distinct and abundant soils, with and without REY competition, and over a range of pH are explained in terms of soil mineralogy (i.e., 2:1 clays in the Mollisol; oxides in the Oxisol) and organic matter content. Our findings show that soil characteristic controls sorption, precipitation, and cation exchange capacity, which are the key mechanisms for predicting REY fate and transport in the environment.


Assuntos
Metais Terras Raras/análise , Solo/química , Brasil , New Mexico
18.
Artigo em Inglês | MEDLINE | ID: mdl-30862075

RESUMO

Waste mobile phones constitute one of the fastest growing Waste Electrical and Electronic Equipment (WEEE) types all over the world due to technological innovations and shortening of their life span. They contain a complex mix of various materials, such as basic metals, precious metals and rare earth elements and represent an important secondary raw metal source. The main objectives of this study were to characterize the metal concentration of waste mobile phones by optimizing the inductively coupled plasma optical emission spectrometer (ICP-OES) operation parameters and estimate the metal recovery potential of waste mobile phones in Turkey. Therefore, selected mobile phone samples collected from a recycling center in Turkey were analyzed to determine their metal concentrations. Then, the theoretical recovery potentials of precious and rare earth metals from waste mobile phones were estimated for Turkey. The analytical methods optimized in this study can help further research activities to obtain comprehensive data for determination of the critical metals (precious metals and rare earth elements) in WEEE samples so that proper recycling and recovery strategies can be selected and implemented.


Assuntos
Telefone Celular , Metais Terras Raras/análise , Metais/análise , Reciclagem/métodos , Resíduo Eletrônico/análise , Turquia
19.
Meat Sci ; 153: 45-50, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30878822

RESUMO

Rare Earth Elements (REEs), La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Y, & two actinides, Th and U were assessed in muscle and liver tissues of wild, backyard and commercially raised rabbits through ICP-MS. Higher concentrations were found in liver in comparison to muscle tissue. Liver of wild rabbits accumulates all studied elements beyond Tm. Backyard rabbits do not show any statistically significant accumulation while commercial accumulate all beyond La, Ce, Pr, Nd, Gd and Tb. Wild rabbits were with the highest amounts for most of these elements. The different living and rearing environments of wild, backyard and commercial rabbits may affect accumulation, fate and transfer of REEs in rabbits' tissues. A dataset for establishing reference values of REEs in Lemnos island wild rabbits' is shown and the literature gap on safety limits for REEs is discussed.


Assuntos
Metais Terras Raras/análise , Coelhos , Animais , Grécia , Fígado/química , Carne/análise , Músculo Esquelético/química , Tório/análise , Distribuição Tecidual , Urânio/análise
20.
Sci Total Environ ; 670: 950-960, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-30921727

RESUMO

Overexploitation of rare earth elements (REEs) has caused serious desertification and environmental pollution. The ecological restoration of mining areas has attracted increasing attention in China. Soil microbiota is important for successful ecological remediation of abandoned mine land. In this study, soil samples were collected from a restored REE mine site, and the bacterial community composition and diversity were assessed by Illumina high-throughput sequencing targeting the V3-V4 region of the 16S rRNA gene. Microbiota significantly developed in the remediated land. A total of 663,781 effective 16S rRNA gene sequences were obtained, which were classified into 28 bacterial phyla and 3 archaeal phyla. The dominant phyla across all samples (>5% of total effective sequences) were Proteobacteria, Acidobacteria and Firmicutes. Bacterial diversity indices (OTU number, Shannon index and Chao1 index) of the restored soils were higher than those of the tailings and even surpassed those in the unmined site. Redundancy analysis indicated that soil nutrients (soil organic carbon, available phosphorus and total nitrogen) were the dominant factors, followed by soil pH, affecting bacterial community structure. In general, these results suggested that soil amendment and phytoremediation effectively improved the soil environment of the abandoned mine site, which also increased our understanding of the correlation between microbial variation and soil properties in restored REE mine soils.


Assuntos
Biodegradação Ambiental , Metais Terras Raras/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , China , Metais Terras Raras/análise , Mineração , Proteobactérias , Solo , Poluentes do Solo/análise
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