Normalized Rare Earth Elements Patterns Research Articles

Accumulation of rare earth elements in human gallstones: a perspective from dietary and human health

BackgroundGallstone disease poses a global threat to human health and is strongly linked to environmental factors. However, there is currently no data on the presence of rare earth elements (REEs) in human gallstones. This paper investigates the concentration and distribution of REEs in gallstones for the first time, aiming to explore the environmental implications on human health.MethodsA total of 25 gallstone samples were collected in Shanghai and the content of REEs was measured by Inductively coupled plasma-Mass Spectrometry (ICP-MS) to explore the distribution of REEs in gallstones.ResultsThe concentration of REEs in gallstones ranged from 4.89 to 190.8 ng/g (mean 39.21). In most of the gallstone analyses, REEs have been detected and generally attributed to environmental exposure or food contamination. The Y/Ho ratio of gallstones was lower than that of continental rocks, similar to that in the blood, indicating limited fractionation during fluid transport processes in the gallbladder.ConclusionsThe upper continental crust (UCC)-normalized REEs pattern in gallstones showed depletion of light REEs, while most showed enrichment of heavy REEs. Positive Gd anomalies were found in most samples, while few samples suggested anthropogenic influence. Whether exogenous inputs or in vivo biofractionation lead to changes in REEs fractionated patterns require further analyses.

Anthropogenic impact of rare earth elements on groundwater and surface water in the watershed of the largest freshwater lake in China

Limited knowledge exists regarding the potential risks associated with anthropogenic release of rare earth elements (REEs) in the environment. This study aimed to investigate REE signatures in the watershed Poyang Lake, the largest freshwater lake in China. Samples of surface water, wastewater, and groundwater were collected from five rivers discharging into the lake. Results revealed wastewater from wastewater treatment plants contained total REE concentrations from 231 to 904 μg/L, exceeding those found in surface water (0.4 to 1.3 μg/L) and groundwater (0.5 to 416 μg/L). Samples with elevated REE were found in Ca-Mg-Cl/SO4 type waters and exhibited an 18OD deviation from local meteoric water line. Wastewater exhibited a higher positive Gd anomaly compared to surface water and groundwater, attributed to anthropogenic input of Gd (Gdanth). The determined Gdanth concentration ranged from 0.04 to 0.21 μg/L, and from 0.06 to 0.37 μg/L, accounting for 4 % to 21 % and 49 % to 84 % of total Gd concentrations in groundwater and surface water, respectively. Gdanth concentration in wastewater (0.19 to 0.43 μg/L) remained constant in effluent after wastewater treatment. Surface water displayed relatively complex normalized REE patterns influenced by anthropogenic activities and natural processes (weathering and complexation), while groundwater exhibited heavy REEs enrichment, due to carbonate solution complexation. Additionally, Gdanth concentration showed a positive correlation with ΣREE, Pb, Ni, and Co concentrations in groundwater, indicating a good pollution tracing potential. Health risk assessment using the hazard quotient (HQ) suggested higher HQGd values in groundwater compared to surface water. Residents in the eastern part of Poyang Lake were found to face higher risks associated with Gd in groundwater compared to the western part, with infants and children at greater risk than adult males and females. These findings offer valuable insights into environmental behavior and health risks of REEs in aquatic systems impacted by human activities.

Rare Earth Element Characteristics of Shales from Wufeng-Longmaxi Formations in Deep-Buried Areas of the Northern Sichuan Basin, Southern China: Implications for Provenance, Depositional Conditions, and Paleoclimate.

To explore the sedimentary environment and the background of the source area of organic-rich shales in the Wufeng-Longmaxi Formations in the northern Sichuan Basin, samples from Well XX1 in the area were subjected to geochemical testing and analysis of organic carbon content, trace elements, and rare earth elements (REEs). The results show that the total content of REE (ΣREE) of the shale in the Wufeng-Longmaxi Formations varied from 183.08 to 234.66 μg/g with an average of 212.59 μg/g, which is significantly higher than the content of the North American shale composite. The fluctuations in the total amount of REEs in the shale of the Wufeng-Longmaxi Formations reflect certain differences in the geochemical conditions of the Upper Ordovician-Lower Silurian shale. The ratios of LREE/HREE, LaN/YbN, LaN/SmN, and GdN/YbN and the distribution of normalized REE patterns indicate that the source supply or sedimentary structural background may have changed during the shale deposition period of the Wufeng Formation, while the shale deposition period of the Longmaxi Formation may be in a relatively stable source supply and sedimentary structural background. There is no significant correlation between δCe and ΣREE, and the obviously negative Eu abnormity and the weak Ce abnormity indicated that the diagenesis had a limited impact on REEs. Geochemical parameters such as values of ∑REE, δEu, δCe, Ceanom, and LaN/YbN indicate that the climate during the Wufeng-Longmaxi Formation shale deposition period was warm and humid, and the shale was deposited mainly in the suboxic-anoxic water environment. The deposition rate was stable and slow, providing good conditions for the production and preservation of organic matter. At the same time, this shows that the water environment of Wufeng Formation is more anoxic and reductive than that of Longmaxi Formation, which is more conducive to the preservation of organic matter. The correlation between ΣREE and the content of Sc, Ti, Cr, Co, Zr, Nb, Th, Hf, Ta, and other elements indicates that the sources of REEs in the shale of Wufeng and Longmaxi Formations in the study area are similar, mainly terrestrial clasts, and some may come from the sea. The REE distribution pattern shows that the shale provenance of the Wufeng-Longmaxi Formations mainly comes from the upper crust. The La/Yb-∑REE diagram shows that the sediment-parent rocks are mainly early sedimentary rocks and these sediment-parent rocks have granite provenance characteristics. Compared to La/Yb, LREE/HREE, LaN/YbN, and other REE characteristic parameters, it is inferred that the tectonic background of the study area is dominated by passive continental margin.

Trophic transfer of rare earth elements in the food web of the Loire estuary (France)

The increasing use of rare earth elements (REEs) in many industrial sectors and in medecine, causes discharges into the environment and particularly in estuarine areas subjected to strong anthropogenic pressures. Here, we assessed the distribution of REEs along the food web of the Loire estuary. Several species representative of different trophic levels were sampled: 8 vertebrates, 3 crustaceans, 2 mollusks, 3 annelids and 4 algae, as well as Haploops sp. tubes rather related to sediment. The total REE concentrations measured by ICP-MS were the highest in Haploops sp. tubes (141.1 ± 4.7 μg/g dw), algae (1.5 to 34.5 μg/g dw), mollusks (9.9 to 12.0 μg/g dw), annelids (0.7 to 19.9 μg/g dw) and crustaceans (1.4 to 6.3 μg/g dw) and the lowest in vetebrates (0.1 to 1.6 μg/g dw). The individual contribution of REEs was, however, similar between most studied species with a higher contribution of light REEs (76.7 ± 7.6 %) compared to heavy REEs (14.1 ± 3.7 %) or medium REEs (9.2 ± 5.8 %). Trophic relations were estimated by stable isotope analysis of C and N and the linear regression of δ15N with total REE concentrations highlighted a trophic dilution with a corresponding TMS of −2.0. The tissue-specific bioaccumulation investigated for vertebrates demonstrated a slightly higher REE accumulation in gonads than in the muscle. Finally, positive Eu, Gd, Tb and Lu anomalies were highlighted in the normalized REE patterns of most studied species (especially in fish and crustaceans), which is consistent with results in the dissolved phase for Eu and Gd. These anomalies could either be due to anthropogenic inputs or to various bioaccumulation/elimination processes according to the specific species physiology. This study, including most of the trophic levels of the Loire estuary food web provides new insights on the bioaccumulation and trophic transfer of REEs in natural ecosystems.

Variability of rare earth and heavy metal elements in a representative alluvial depositional system.

Heavy metals (Ni, Cr, W, Cd, and Pb) and rare earth elements (REE) were investigated in the flood plain sediments of an island of the lower Yangtze River near Nanjing to determine how the vertical distribution of heavy metals could be affected by natural sedimentation processes and anthropogenic contamination. Stratigraphic analyses of magnetic susceptibility and the mean grain size distribution of the deposits enabled us to identify layers associated with a relatively high influx of suspended sediments that resulted in sudden changes in the concentrations of heavy metals. The results show that layers associated with high sediment influx (0.8m depth) displayed low concentrations of Cr, Ni, W, and Cd that were mainly lithogenic in origin. The Post Archean Australian Shale (PAAS) normalized REE patterns in the flood plain cores were enrichment in Ce and Eu relative to PAAS, indicating that the sediments were most likely derived from a mixture of sediments and not from an anthropogenic source. Sharp increases in Y/Ho ratios, as well as heavy metal (Cd, Cr, Ni, and W) and Y concentrations were observed in the uppermost layer that could have been deposited from the rapid transport of sediment-laden, contaminated waters. The temporal (vertical) trends in Pb concentrations may be strongly influenced by coal burning. Elevated Pb concentrations (350ppm and 1000ppm) correlate with high magnetic susceptibility (> 200 m3 × kg-1) and the history of thermal power plant (1910-2002) activity. The anthropogenic inputs of Pb were, however, not diluted by high suspended sediment loads, which supports the argument that Pb was derived from fly ash.

First assessment of Rare Earth Element organotropism in Solea solea in a coastal area: The West Gironde Mud Patch (France)

Few studies exist on concentration and internal distribution of Rare Earth Elements (REEs) in marine fishes. REEs organotropism was determined in common sole (Solea solea) from the West Gironde Mud Patch (WGMP; N-E Atlantic Coast, France). The highest ∑REEs concentrations occurred in liver (213 ± 49.9 μg kg−1 DW) and gills (119 ± 77.5 μg kg−1 DW) followed by kidneys (57.7 ± 25.5 μg kg−1 DW), whereas the lowest levels were in muscles (4.53 ± 1.36 μg kg−1 DW) of Solea solea. No significant age- or sex-related differences were observed. The organotropism varied among groups of REEs. Light and heavy REEs preferentially accumulated in liver and gills, respectively. All considered organs showed different normalized REEs patterns, suggesting differences in internal distribution processes between organs. Further work should address: (1) baseline levels worldwide, and (2) factors controlling uptake and organ-specific concentration of REEs.

Geochemical significance for the composition and depositional environments of the Campanian carbonate-rich phosphorite, Abu-Tartur plateau, Western Desert, Egypt

Twenty-six samples involved CFA (carbonate fluor-apatite) and intercalated marl were collected from four outcrops of the Campanian phosphorites horizon extending along 9 km of a minable NE-SW side wall of the Abu Tartur Plateau. Samples were analyzed chemically using XRF (x-ray fluorescence) and ICP-OES (Inductively coupled plasma optical emission spectrometry) techniques for measuring oxides, trace elements, and REE (Rare earth elements) for deducing their implication for the paleo-depositional environment. The CFA samples show an average compositional richness in major oxides of CaO (42.23 wt%) and P2O5 (27.22 wt%) with a considerable amount of F (2.75%). Whilst the main average composition of the intercalated marl is SiO2 (54.17 wt%) and CaO (10.58 wt%). The geochemical classification of this marl shows a type of Fe-sand (Ferro-magnesium potassic sandstone). The P2O5 in the marl samples does not exceed 3.46 wt%. Calculation of the CaO/MgO molar ratio of studied samples reveals evidence of the dolomitization process took place, making a conversion of approximately 65.73% of the entire CFA to be dolomitic- and highly dolomitic-francolite may occur over a long time post of the Campanian age. CFA samples have an amount of Fe2O3 ranging from 3.15 wt% to 5.84 wt% (average 4.31 wt%) whereas Fe2O3 in the marl samples range from 3.81 wt% to 6.03 wt% (average 4.41 wt%). The origin of iron is attributed to being delivered by an ancient river system laden from hot, humid chemically weathered (laterite) soils into the basin simultaneously with the dolomitization process. Less saline mixed water is the suggested medium where dolomitization processes occur based on Rb/Sr and Sr/Ba ratios. The normalized REE pattern of the base, middle and top parts of the CFA samples show a similarity of fingerprint patterns of near-shore and margin-marine of either bottom seawater and shallow-to deep-pore-water below the SWI (sediment-water interface). Dysoxic to oxic depositional environments of the marginal shelf are established based on measured trace elements ratios of V/Cr, Ni/Co and V/(V + Ni). The accumulation rate of P shows a progressively increasing trend toward the NE direction of favourable P depositional conditions. The results of the Ce/Ce* and Pr/Pr* anomalies show no-to + ve Ce/Ce* lie between 0.93 and 1.45 (average 1.04) and the Y/Ho ratio lie between 23.43 and 87.75 (average 51.63) which is attributed to depositional sets within the shelf margin of suboxic to anoxic pore-water chemistry conditions at bottom seawater below the sediment-water interface. The fingerprint shape of the REE patterns and the richest of HREE (Heavy rare earth elements) of the studied CFA samples reflect the chemistry of the shallow to the deep pore-water flux of suboxic-anoxic sulfidic characters.

Trace and Rare Earth Element (REE) Geochemistry of Recently Formed Stromatolites at Lake Salda, SW Turkey

Stromatolites are the oldest recognized fossil recordings of life on Earth. Therefore, their study of them represents one of the most interesting topic that investigates the physio-chemical environmental conditions (formations and precipitations) at which the stromatolites formed. This work deals with the rare earth elements (REEs) geochemical characteristics and the redox-sensitive trace elements behavior of the stromatolites newly formed in Salda Lake, a closed system alkaline lake surrounded by serpentinite rocks in SW Turkey. The representative stromatolite samples collected from Salda Lake show higher contents of MgO (up to 41.5 wt.%), CO2+OH (up to 56.6 wt.%), and MgO/CaO ratio (up to 42.2 wt.%) referring to the stromatolites had been controlled by microorganisms and deposited in subtidal areas having hydro-magnesite and aragonite mineralogy. The average trace element contents of the stromatolites are 8.4 ppm V, 0.09 ppm Cr, 3.50 ppm Co, 95.6 ppm Ni, 0.73 ppm Cu, 1.55 ppm Rb, 37.6 ppm Sr, 0.59 ppm Y, 17.7 ppm Zr, 3.60 ppm Nb, 21 ppm Ba, 0.05 ppm Hf, 3.5 ppm As, 0.02 ppm Cd, 0.05 ppm U, 0.05 ppm Th, 2.85 ppm Pb, and 6.60 ppm Zn. The Post-Archean Australian Shale (PAAS)-normalized REE patterns of the stromatolites reveal that the heavy REEs (HREEs) are enriched relative to the light REEs (LREEs) with highly negative Y and Ce-anomalies and positive Eu-anomalies. This refers to the stromatolites formed in predominantly oxidizing environmental conditions at partially warm lake waters. In addition, the hydromagnesite composition of the Salda Lake stromatolites indicates that they were precipitated from the waters influenced by Mg-rich meteoric waters fed from the serpentinite rocks around the Lake.

Forearc and back-arc mantle characteristics of the mafic-ultramafic rocks of Simlipal complex, Singhbhum Craton, India

The Simlipal complex of Singhbhum Craton is enigmatic in terms of its shape, stratigraphy, age and geodynamic setting. The circular-shaped Simlipal complex has predominant mafic volcanic rocks and quartzites associated with komatiites, komatiitic basalts, picrites, boninites, andesites and other ultramafic rocks. The mafic rocks are subalkaline tholeiitic basalts to basaltic andesites with moderate SiO2 (45.94–54.26 wt%), MgO (6.09–12.21 wt%), Fe2O3 (10.02–16.44 wt%), CaO (8.33–12.12 wt%), Mg # (32–58), low TiO2 (0.4–1.02 wt%), P2O5 (0.08–0.34 wt%), Ni (112–241 ppm) and Cr (104–506 ppm). The chondrite normalized rare earth element (REE) patterns are slightly fractionated [(La/Yb)N = 2.97–5.44] with slight negative to positive Eu anomalies (Eu/Eu* = 0.84–1.46). Their primitive mantle normalized multielement patterns exhibit negative Th, Nb, Ta and positive to negative Ti anomalies. The ultramafic rocks characterized as harzburgites, have high MgO (34.77–38.11 wt%), Ni (1974–2453 ppm), Cr (3875–4610 ppm) and Mg# (80–85), low SiO2 (40.61–44.18 wt%), TiO2 (0.08–0.14 wt%), Al2O3 (2.24–3.79 wt%), Fe2O3 (7.24–9.77 wt%) and P2O5 (∼0.05 wt%). Their chondrite normalized REE patterns exhibit fractionated LREE [(La/Sm)N = 2.07–2.37], depleted MREE, almost flat HREE [(Gd/Yb)N = 0.99–1.14] and a pronounced trough at Nb-Ta; ZrHf and Ti on the primitive mantle normalized multielement patterns. The basalt gave a zircon UPb age of 2843 ± 16 Ma (MSWD = 0.72) which is the crystallization age. HFSE relationship of the basalts indicates back-arc nature and their melting in the spinel-lherzolite field. The peridotites are arc cumulates, exhibiting boninitic characteristics and forearc affinity. Their PGE systematics indicate retention of sulphides in the residue during the partial melting and fractionation of the mantle. These peridotites and basalts were generated in forearc and back-arc environments during the Neoarchean time, subsequently juxtaposed with plume-derived volcanic sequences and the passive margin sediments as the arc progressed towards the continent. The plume-arc accretion model (PAA) is a viable tectonic setting with the presence of komatiites, komatitic basalts, picrites, tholeiitic basalts and peridotites. Further, the metasediments from the passive continental margin accreted with PAA products in the Simlipal complex. The above findings also support the existence of Archean smaller plate configuration and the proximity of the arc to the continental margin. After the formation of the volcano-sedimentary sequences, the meteoritic impact appears to have obliterated the accretionary imprints in the Simlipal complex.

Geology and geochemistry of the high-grade Zankan magnetite ore, Western Kunlun Mountains, NW China

Over the past decade, several magnetite-rich iron deposits have been discovered in the Taxkorgan region of the western Kunlun Mountains of northwestern China. These include the Zankan, Jiertieke, Laobing, Yelike, and Taaxi iron deposits. Prospective iron ore reserves are estimated at over 1 billion tons, with an average magnetite grade of 28% (Feng et al., 2018). The largest of the deposits, the Zankan Iron Deposit (ZID), is estimated to contain 628 million tons of iron ore, with at least 10% of the ores being high-grade (TFe > 50 wt%). However, the geological processes by which the high-grade ores in the ZID were formed remains poorly constrained. In this study, we combine whole rock and ore geochemistry data, oxygen and sulfur stable isotopes, and uranium-lead and hafnium isotopes from zircons to elucidate the plausible mechanisms underpinning the formation of the ZID ores. Based on mineralogy, we define two ore types. Type 1 is essentially comprised of quartz and magnetite, interlayered with schist, and it retains the sedimentary fabrics of the precursor iron-rich sediments which were an iron formation (IF). Type 2 formed by the intrusion of a dacite-porphyry into the IF which led to magnetite remobilization and recrystallization as manifest in magnetite-ferro actinolite veining. Rare earth element (REE) characteristics of the high-grade ores differs from those of the precursor IF, with chondrite normalized REE patterns showing enrichment of LREE and significant negative europium anomalies close to those of the dacite-porphyry. The oxygen and sulfur isotopic composition of magnetite and pyrite in the high-grade ores suggests a further meteoric influence on the ZID with silica enrichment driven by leaching of the precursor IF from elsewhere in the sequence. Circulation of the ore forming fluid is attributable to the development of faults and fracture zones that resulted from the intrusion of the dacite-porphyry. Laser ablation uranium-lead analyses of zircons from the dacite-porphyry yield two groups with ages of 551.25 ± 3.32 Ma and 497.82 ± 3.81 Ma, representing captured detrital zircons and the intrusive age of dacite porphyry, respectively. Given the intimate geological relationship between the dacite-porphyry and T2 ore, we suggest that the high-grade ores are formed after 497.82 Ma. Collectively our field observations and geochemical data reveal the detailed alteration processes that led to the development of the high-grade iron ores in the ZID, identifying distinctive features that may help to guide future exploration for additional high-grade ore deposits in the Taxkorgan region.

Implications for catchment weathering, provenance, and climatic records from a late Pleistocene to present sedimentary sequence in Gujarat, India

AbstractTo ascertain weathering, provenance, and paleoclimate of the last ca. 29 ka in mainland Gujarat, western India, a sedimentary profile of ~7.5 m was measured, described, and sampled at Pratappura and a multiproxy analysis was conducted. To determine weathering, silty-sand and sandy-silt facies were analyzed, and log Na2O/K2O versus log SiO2/Al2O3 was plotted, which shows clustering in the quartz arenite and sub-litharenite categories, indicating low to moderate weathering. The chemical index of alteration (CIA) is 55–74, and was plotted versus the index of chemical variability (ICV) of 1.50, with samples clustered mainly between subalkali basalt and picrite, indicating the dominance of a mafic component. While depleted chondrite normalized light rare earth element (REE) (La/Yb <1) levels suggest the prevalence of a mafic source in the catchment, identical chondrite normalized REE patterns indicate that sediments were well homogenized. Using multiple proxies, the measured profile was subdivided into five paleoclimatic zones. Zone-I (29–18 ka) exhibits decreasing moisture, Corg, χlf, Al2O3, TiO2, and Fe2O3 trends, while higher values of CO3−2 and δ13C indicate a change from a warm-humid to semiarid climate. Zone-II (18–11 ka) shows signs of the beginning of aridity ca. 18 ka during the Last Glacial Maximum (LGM). Several proxies in zone-III show wetter climatic conditions from the early Holocene (ca. 11–4 ka) due to the onset of the SW monsoon, with the trend continuing in zone-IV (4–2 ka). In zone-V, the climate appears to have been similar to the modern conditions in the area from 2 ka–present.

Determination of Scandium (Sc), Yttrium (Y), and Rare-Earth Elements (REEs) in Mafic and Ultramafic Rock Powder by a Modified and Validated Digestion Protocol and Inductively Coupled Plasma – Mass Spectrometry (ICP-MS)

The global demand for rare earth elements (REEs) has been associated with the increased use of renewable energy technologies. However, due to the low occurrence of REEs in economic sources, such as geologic samples, it is essential to employ suitable sample preparation methods and measurement techniques that allow for reliable quantification. While acid digestion procedures have been conventionally used to free metals from silicate rocks, few studies have evaluated these methods for quantitative measurement of REEs, including Sc and Y in mafic-ultramafic rocks. This study involves validating a modified digestion procedure to facilitate the determination of Sc, Y, and REEs in mafic-ultramafic matrices. Three reference materials (RMs) (OKUM, BHVO-1, and JB-1a) were used to assess the performance of this modified method. The calculated percent error (< 10%) for most elements was in good agreement with the reference values, except La in OKUM, Er in BHVO-I, and Eu, Gd, Tb, Ho, and Er in JB-1a. The precision of the modified method was satisfactory, with values generally below 5%. The smooth chondrite normalized REE patterns indicate good quality data. The t-values of the studied elements were lower than the t-critical value (± 12.71), suggesting no significant differences between the analytical and Intertek values. Thus, the modified method could be used as a viable alternative in determining REEs in Ni laterite samples by ICP-MS.

The mobility of thorium, uranium and rare earth elements from Mid Ordovician black shales to acid waters and its removal by goethite and schwertmannite

Previous studies have addressed the occurrence of Acid Rock Drainage (ARD) affecting La Silva stream due to the generation of large dumps of Middle Ordovician black shales during the construction of a highway close to El Bierzo (León, Spain). This ARD was characterized by sulphated acid waters with high concentration of heavy metals and anomalies in dissolved thorium (Th) and uranium (U). In the present study, we analyse in depth black shales and water, streambed sediments and precipitates of La Silva stream and its tributaries using different petrographic, mineralogical and geochemical approaches. Black shales, with average Th and U contents of 20 and 3 μg/g respectively contain disseminated detritic micro-grains of high weathering-resistant minerals, such as monazite and xenotime, that present smaller amounts of yttrium and rare earth elements (REY) and other elements as Ca, U, Th, Si and F. Results of the affected waters by ARD show an enrichment in dissolved Th, U and REY of several orders of magnitude with respect to natural waters. Sampled precipitates were mainly schwertmannite (Fe8O8(OH)8-2x (SO4)xO16•nH2O) and goethite (α–Fe3+O(OH)) that showed an enrichment of Th (up to 798 μg/g) and REY, due to the presence of dissolved anionic species (e.g. Th(SO4)32−, REY(SO4)32−) that enables their adsorption. Furthermore, these black shales show a clear enrichment in REE (Rare Earth Elements) with respect to NASC (North American Shales Composite) normalized REE patterns. Likewise, normalized REE patterns of stream waters and precipitates clearly show convex curvatures in middle-REE (MREE) with respect to light- and something less than heavy-REE, indicating the trend towards MREE enrichment. These findings are essential to evaluate the impact of ARD of Mid Ordovician shales in the surrounding environment, and to start considering these site as potential source of REE and critical raw materials, activating a Circular Economy.

ICP-MS Measurement of Trace and Rare Earth Elements in Beach Placer-Deposit Soils of Odisha, East Coast of India, to Estimate Natural Enhancement of Elements in the Environment.

Inductively coupled plasma mass spectrometry (ICP-MS) has been used to measure the concentration of trace and rare earth elements (REEs) in soils. Geochemical certified reference materials such as JLk-1, JB-1, and JB-3 were used for the validation of the analytical method. The measured values were in good agreement with the certified values for all the elements and were within 10% analytical error. Beach placer deposits of soils mainly from Odisha, on the east coast of India, have been selected to study selected trace and rare earth elements (REEs), to estimate enrichment factor (EF) and geoaccumulation index (Igeo) in the natural environment. Enrichment factor (EF) and geoaccumulation index (Igeo) results showed that Cr, Mn, Fe, Co, Zn, Y, Zr, Cd and U were significantly enriched, and Th was extremely enriched. The total content of REEs (ƩREEs) ranged from 101.3 to 12,911.3 µg g−1, with an average 2431.1 µg g−1 which was higher than the average crustal value of ΣREEs. A high concentration of Th and light REEs were strongly correlated, which confirmed soil enrichment with monazite minerals. High ratios of light REEs (LREEs)/heavy REEs (HREEs) with a strong negative Eu anomaly revealed a felsic origin. The comparison of the chondrite normalized REE patterns of soil with hinterland rocks such as granite, charnockite, khondalite and migmatite suggested that enhancement of trace and REEs are of natural origin.

Geochemical approach to the genesis of the Buyukkizilcik (Afsin) barite deposit, SE Turkey

This study investigated the geochemistry, mineralogy, fluid inclusion, trace and rare earth element (REE) contents and Pb, O and S isotope results of the barites formed together with Pb-Zn deposits in the region. The Buyukkizilcik barite mineralization is located in the west part of Afsin, Turkey and it can be traced through 14 kilometers in NE-SW direction within the Yoncayolu and Cayderesi Formation. The thickness of these mineralized areas reaches 7-8 m, especially in the middle and eastern part of the ore zone. Mineralization is represented by barite-antimonite-fluorite in the western part, pyrite-chalcopyrite in the middle part and galena-sphalerite in the eastern part of the mineralized zone. Fluid inclusion studies indicate that these mineralizations are formed in the epithermal phase of hydrothermal period, with liquids having 4.5 to 2% NaCl salinity values and temperatures of 105 °C to 121 °C. The barite samples were collected from Buyukkizilcik mineralization area for analysis of major oxides, trace elements, and rare earth elements (REEs) using inductively coupled plasma mass spectrometry (ICP-MS). According to the results of the analysis, it is seen that total trace element contents change from 163 to 20458 ppm and ∑REE contents are between 4.31 and 14.4 ppm. The chondrite- normalized REE patterns of the studied barites exhibit trends decrease from LREE towards HREE and have negative Ce and negative Eu anomalies. The 206Pb/204Pb; 207Pb/204Pb and 208Pb/204Pb isotope values of galena vary between 17.20 and 19.96%o; 14.1 and 16.2%; and 35.4 and 41.9%, respectively. These isotope results show that these mineralizations were originated from upper crust materials. The δ34S values in Buyukkizilcik mineralizations range from 8.2 to 14.4‰. The barite mineralization was formed by hydrothermal activity and that the δ34S values indicate an epithermal phase. The δ18O values of barites are between 17.0 and 18.5‰ and these δ18O values show that the origin of the water displayed in the hydrothermal activity is magmatic and/or magmatic mixed with meteoric water. All results indicate that the barite mineralization was deposited as vein-type by hydrothermal solutions that are transported along fractures and fault zones within the Malatya Metamorphic complexes.

Distribution of rare earth elements and stable isotopic constituents along the groundwater flow paths in the Quaternary deposits of Imphal valley in north‐east India

Groundwater samples collected from three flow paths (the western, central, and eastern flows) in the shallow aquifers of the Imphal valley of north‐east India were examined to study the variation in hydrochemical and rare earth element (REE) characteristics along these flow paths. Each flow path covers a length of around 45 km towards the down gradient. In the western flow, the hydrochemical facies evolved from Na‐Cl‐Ca to Ca‐Na‐Mg‐Cl‐HCO3; in the central flow, it varies from Ca‐Mg‐Na‐Cl to Na‐Ca‐Cl‐HCO3 and in the eastern flow, it changes from Na‐Cl to Ca‐Mg‐HCO3 indicating the evolution of saline water type in the piedmont zone to fresh water type towards the discharge zones around the Loktak Lake. The REE concentration varies along the flow path as the total light REE (LREE) is more enriched than total heavy REE (HREE) in the western and central flows, while LREE is less than HREE in the eastern flow. North American Shale Composite (NASC)‐normalized REE patterns in these flow types show significant convex‐up NASC‐normalized patterns with depleted LREEs. The redox condition in the flow paths is controlled by redox‐sensitive elements such as Eh, pH, Fe, Mn, U, Er, Gd, and Nd which vary relatively along with these flows. REE fractionation depicted by (Er/Nd)SN ratios are high around the upgradient and decrease along the down gradient towards Loktak Lake. The isotopic constituents (δ18O and δD) exhibit fluctuations in their ratios along the groundwater flow paths. The residual hill and piedmont zones are characterized by depleted isotopic composition while the alluvial and flood plains show enriched isotopic composition. Thus, the present study elucidates the behavioural change in major hydrochemical parameters including REE and isotopic constituents, along with the groundwater flow, which will provide a holistic view in understanding the evolution of groundwater in terms of its quality, quantity, and origin in the study area.

Geochemical behavior and fractionation characteristics of rare earth elements (REEs) in riverine water profiles and sentinel Clam (Corbicula fluminea) across watershed scales: Insights for REEs monitoring

The increasing global demand for rare earth elements (REEs) has led to their recognition as emerging contaminants; however, the effect that biota have on the cycling of these elements at the watershed scale is not currently well understood. In this study, water samples and field freshwater clams Corbicula fluminea were concurrently collected along watershed gradients, and concentration profiles of 14 naturally occurring REEs were measured in operationally defined water fractions and soft tissues of the freshwater clams. Moreover, Post Archean Australian Shale (PAAS) normalized REE patterns, fractionation indices, and anomalous values were determined to further extract characteristic features. As a result, both the water and biological samples had variable REE compositions, with higher concentrations of light REEs (LREEs) than middle REEs (MREEs) and heavy REEs (HREEs), while decreasing concentrations were generally observed as filter pore size decreased, implying that large colloidal and particulate fractions were important carriers of REEs. The spatial distribution patterns of REEs revealed a clear site effect among profiles, with variability more pronounced among watersheds and with peaks in sites from a small watershed near the hotspots of the mining area, and then exhibited a decreasing trend with distance from there. Meanwhile, significant bioaccumulation of REEs was observed potentially reflecting different degrees of contamination gradients among the watersheds. The PAAS-normalized distribution patterns tended to be slightly enriched in MREEs, producing a peculiar “roof-shaped” feature and characteristic fractionation. Remarkably, bio-concentration factors (BCFs) highlighted the importance of large colloidal and particulate phases in assessing biologically available REEs for filter-feeding species. Collectively, our study strongly favored that accumulation patterns and fractionation characteristics of REEs in C. fluminea can serve as a reliable indicator of geochemical behavior, providing a promising biomonitoring tool to quantitatively denote different degrees of REE contamination and assess possible impacts in mining watersheds.

Rare Earth Element and Incompatible Trace Element Abundances in Emeralds Reveal Their Formation Environments

Emeralds require the unusual association of typically compatible elements (Cr, V), with incompatible Be to form, and occur in complex tectonic settings associated with sediments (type IIB; Colombia) or, more commonly, with magmatism and regional metamorphism (IA). Precise rare earth element (REE) and incompatible trace element abundances are reported for a global suite of emeralds, enabling the identification of the environments in which they formed. Type IIB emeralds have nearly flat continental crust normalized REE patterns (La/YbCC = ~2), consistent with a sedimentary source origin. Type IA emerald REE patterns have upturns in the heavy REE (La/YbCC = ~0.3), a feature also shared with South African emeralds occurring in Archaean host rocks. Modeling of type IA emerald compositions indicates that they form from magmatic fluids of sedimentary (S)-type granite melts interacting with Cr, V-rich mafic–ultramafic crustal protoliths. This geochemical signature links emerald formation with continental suture zones. Diamonds, rubies, and sapphires have been considered as ‘plate tectonic gemstones’ based on mineral inclusions within them, or associations with plate tectonic indicators. Emeralds are distinct plate tectonic gemstones, recording geochemical evidence for origin within their mineral structure, and indicating that plate tectonic processes have led to emerald deposit formation since at least the Archaean.

Characterization and potential application of gleysols and ferralsols for ceramic industry: a case study from Dimako (Eastern Cameroon)

Gleysol and ferralsol samples were collected at Dimako (Eastern Cameroon) to investigate their use as raw materials in the ceramic industry, using petrological and physicochemical approach. Field and analytical investigations reveal that gleysols are grey-white with sandy clay textures. The organic carbon contents are low in both soil types. These soils are characterized by low cation exchange capacity (CEC) contents (3–5.40 cmol(+)/kg). The mineral assemblage of gleysols comprises quartz and kaolinite with few amounts of anatase and zircon. In ferralsols, the mineralogical composition is quartz, kaolinite, and hematite with accessory anatase, gibbsite, goethite, and zircon. The Fourier-transform infra-red (FT-IR) spectra confirm the presence of kaolinite with ordered structure. Gleysols are richer in SiO2 than ferralsols. However, gleysols are less enriched in Al2O3 than ferralsols. Fe2O3 contents are lower in gleysols (av. = 0.93 wt% at Koba and 1.69 wt% at Dimako) than in ferralsols (6.21–8.79 wt%). The abundance of quartz and kaolinite exhibits low contents in other major elements and several trace elements (including rare-earth elements (REE)) except Zr, Sr, and Ba in some samples. The normalized REE patterns relative to parent rocks (gneisses and granites) and chondrite reveal negative and positive Ce anomalies, strong negative Eu anomalies, and intense REE fractionation. Both soils result from the intense chemical weathering of gneisses and granites under tropical humid climate. Technological properties (color, grain size distribution, linear shrinkage, water absorption, and flexural strength) increase with the firing temperature, from 1000 to 1200 °C. Petrological and technological features highlight that gleysols are inorganic clays appropriate for refractory bodies and white stoneware tiles.

Utilize gadolinium as environmental tracer for surface water-groundwater interaction in Karst

The rare earth element (REE) group is widely used for geochemical prospection and the hydrochemical differentiation of waters. Most of the currently applied methods use normalized REE patterns to determine enrichments or depletions of certain REE in comparison to standard materials, which are caused by specific environmental conditions. Contrast agents containing Gadolinium (Gd), which are used for magnetic resonance imaging (MRI), have been emitted into surface waters since the 1980s. Patients excrete these contrast agents shortly after ambulant medication in hospitals or at home. Sewage treatment is currently unable to hold back Gd from this anthropogenic source. Therefore, the Gd concentration in the receiving channel increases significantly and creates a Gd peak in the REE pattern. This anthropogenic peak propagates into adjacent groundwater bodies. In a karst aquifer showing a connection between a river/ponor (input) and three springs (output), such an anthropogenic Gd anomaly has been traced, the local Gd background quantified, and surface water groundwater interaction evaluated. In two sampling campaigns, water samples were taken every day at the input and output side during one week in February and three weeks in May. Sampling of springs and brooks in the vicinity of the karst aquifer proved excessive Gd from anthropogenic sources. The evaluation of concentration, mass flow and total mass of Gd show that Gd can be an environmental tracer to monitor surface water-groundwater interaction as well as the anthropogenic influence on water bodies. Further anthropogenic pollutants - diclofenac, carbamazepine, galaxolide, caffeine, and acesulfame-K - representing different classes of common organic substances were tested as co-indicators to Gd. However, out of these only acesulfame-K was detected and is related with the Gd-anomaly. Our results indicate that Gd is a more powerful indicator of surface water- groundwater interaction than most organic pollutants.