Gd Anomalies 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.

Cenozoic faulting leading to petroleum escape in SW Ordos Basin, China: Evidence from fault-related calcite in situ U-Pb dating, rare earth elements and fluid inclusions

Understanding the link between fault activity and movement to petroleum escape is crucial for assessing the petroleum exploration potential in sedimentary basins. As a significant petroliferous basin in China, the Ordos Basin hosts the world-class uncompartmentalized Jingbian natural gas field within the Ordovician marine carbonate reservoirs. However, the role of the unique exhumation history and the Cenozoic faulting in the formation of such large-scale oil-gas fields remain unclear. Our study combines fault-related calcite U-Pb dating with fluid inclusions analysis offers a unique opportunity to trace petroleum leakage along the the carbonate strata brittle fault zones in the SW Ordos Basin. Calcite samples collected from the carbonate fault zone and across the Ordovician carbonate strata in the SW Ordos Basin reveal clear positive Eu anomaly, slight positive Y anomaly, the lack of positive La and Gd anomalies, and the absence of a negative Ce anomaly. The Y/Ho ratios range from 29 to 36, with an average value of 32, indicating calcite formation in a hydrothermal environment during fault activation. U-Pb dating of these fault-related calcites yields ages of 32.8 ± 3.3 Ma and 23.7 ± 7.4 Ma. Raman spectroscopy of fluid inclusions reveals the presence of CH4 gas, coeval with the fault-related calcite. The homogenization temperatures (Th) of aqueous inclusions coeval with CH4 inclusion from two calcite veins range from 140.0 to 172.4 °C (average Th = 157.8 °C, n = 16) and 127.7–154.3 °C (average Th = 142.2 °C, n = 18). Low temperature thermochronology suggest rapid uplift since 40 Ma, potentially linked to fault activity. The Cenozoic erosion rate was 0.06 mm/y during the ∼9 Myr period from 32.8 to 23.7 Ma in the SW Ordos Basin, suggesting that Cenozoic faulting may have created permeable pathways for petroleum escape. This study provides a temporal link between Cenozoic uplift, faulting, and petroleum loss in SW Ordos Basin.

Anthropogenic gadolinium in the Tone River (Japan): an update showing a 7.7-fold increase from 1996 to 2020

BackgroundAnthropogenic gadolinium (Gd), originating from Gd-based contrast agents (GBCAs) used in magnetic resonance imaging (MRI), is widely identified in the aquatic environment with concerns about toxicity and accumulation. We aimed to present new data on anthropogenic Gd in the Tone River, which has the largest drainage area in Japan, and then to compare the current data with those obtained in 1996.MethodsThe water samples were collected on August 9−10, 2020, at 15 different locations of the Tone River in Japan. The concentrations of the rare earth elements (REEs) were measured by inductively coupled plasma-mass spectrometry and normalized to Post-Archean Australian Shale to construct shale-normalized REE patterns. The degree of Gd-anomaly was defined as the percentage of anthropogenic Gd to the geogenic background and used to compare the water samples from different locations. Pearson’s correlation coefficients were calculated.ResultsAll the samples displayed positive Gd anomalies. The Gd-anomaly ranged from 121 to 6,545% and displayed a repeating decrease-and-increase trend. The Gd-anomaly showed strong positive correlations to the number of hospitals (r = 0.88; p < 0.001) and their MRI units (r = 0.89; p < 0.001).ConclusionsOur study revealed notable anomalies of Gd concentrations in river water in Japan, with strong positive correlations to the number of major hospitals and their MRI units. Compared with the previous report in 2000, the Gd-anomaly in Tone River increased from 851% (sampled in 1996) to 6,545%, i.e., 7.7 times, reflecting the increased use of GBCAs in hospitals.Relevance statementNotable Gd concentration anomalies in river water in Japan were observed. This result underlines the importance of more extensive research on anthropogenic gadolinium, and investigations of risks to human health as well as the development of effective removal technologies may be necessary.Key points• All water samples from Tone River displayed positive Gd anomalies.• The Gd anomalies increased to 7.7 times higher over the past 24 years.• Correlations between Gd values and the number of hospitals and MRI units were observed.Graphical

Anthropogenic Gadolinium Anomalies in an Alluvial Plain with On-site Wastewater Treatment Systems in Campinas, SP, Brazil

Gadolinium anomalies have become a well-established marker for the pollution caused by wastewater, but there is not yet a standardized method to estimate the anomaly. Here, we compare four different published equations, distinct threshold values and reference normalizing values to estimate Gd anomalies by applying them to the results of a hydrochemical investigation in an alluvial aquifer with on-site sanitation systems. We measured traditional wastewater markers (such as electric conductivity, NO3_N, NH4–N, Cl-) and REE in groundwater samples collected from hand-dug wells in two seasons. The ratios of Gd normalized measured concentrations to Gd normalized geogenic concentrations (GdSN/Gd*) estimated with the various methods ranged from 0.7 to 2.8. It turned out that the choice of the equation and the threshold value can affect the decisions about anthropogenic pollution’s occurrence (or not). The normalizing values did not play a significant role in the decision. Based on measurement uncertainties and on the interpretation of hydrogeological conditions in the study area, a threshold value of 1.3 for defining anthropogenic Gd anomalies was deemed adequate for the study area. The occurrence of Gd anomalies higher than 1.8 in two wells, one in each season, reinforces the hypothesis that the groundwater is contaminated by the on-site sanitation systems in the study area, as intermittent detection of anthropogenic Gd is a characteristic of this pollution source.

Anthropogenic gadolinium sources and remediation in highly urbanized river in the Beijing-Tianjin-Hebei (BTH) region, China: Insights from buffer zone and three-dimensional tracer system

As a newly emerging microcontaminant, rare earth elements (REEs), especially gadolinium (Gd) in surface water, are attracting great environmental concern in large urban cities. The Beijing-Tianjin-Hebei (BTH) region stands as the preeminent urban agglomeration in northern China, whereas the riverine Gd characteristics and environmental impacts on this region remain inadequate. This study analyzed 27 river water samples in BTH, all of which displayed evidently positive Gd anomalies ranging 1.44–290.75. Spearman correlation indicated the positively correlated REEs concentrations in river water with urban land and cultivated land. A three-dimensional tracing system was established involving anthropogenic Gd (Gdanth) and conventional ion ratios (NO3−/Na+, Cl−/Na+). This system effectively discerned the influences originating from sewage treatment plants, wastewater treatment plants, hospitals, and factories within the BTH region. Gd-based contrast agents (GBCAs) manifest notable potential ecological toxicity and adverse health effects when getting exposed. However, traditional wastewater treatment methods demonstrate limited efficacy in removing these pollutants completely from urban water. To deal with this challenge, this study proposed a new method by combining the latest GBCAs remediation technology with mixing membrane wastewater treatment. This technology may shed light on the potential of an economical and operational procedure of handling medical wastewater specifically in urban water.

Геохимия редкоземельных элементов и цериевая аномалия в морских осадочных карбонатах: современные представления

The article review the geochemistry of rare earth elements (REE) in sedimentary marine carbonates (limestones and dolostones) with respect to using the cerium anomaly as a proxy for redox conditions in ancient seawater. The physicochemical properties of REE and Y, the problem of normalizing their contents in sediments, behavior in the World Ocean and in chemogenic deposits, the origin of La, Ce, Eu, Gd anomalies and their calculations, sample preparation techniques, contamination problem and the influence of non-carbonate REE+Y-hosting phases to whole rock and acidic leachate compositions, as well as criteria for determining seawater-like pattern are considered.

Concentration, speciation, and fractionation of rare earth elements in alluvial soils in contiguous karst landform, southwestern China

Karst is a unique landform formed by strong chemical weathering of carbonate rocks. This study investigated the concentration and speciation of rare earth elements and yttrium (REY) in alluvial soils and REY fractionation from carbonate rocks and alluvial soils in the world's largest contiguous karst landform in southwestern China. The results showed that the REY of alluvial soils ranged from 73.77 to 1251.56 μg⋅g−1, with a median value of 230.30 μg⋅g−1, which was higher than that of alluvial soils across China (178 μg⋅g−1) and the upper continental crust (168 μg⋅g−1), revealing a high background of REY in these karst areas. Meanwhile, the average REY in alluvial soils (244.96 μg⋅g−1) was close to 14 times that in carbonate rocks (17.61 μg⋅g−1) in the study area, indicating that REY was significantly enriched in the pedogenesis. Correlation analysis showed that the REY concentration was not significantly related to any single factor (i.e., Fe2O3, MnO, Al2O3, TOC, pH, or CIX). BCR speciation analysis revealed a declining trend in the proportion of REY across the residual (F4, 73.21 %), reducible (F2, 19.40 %), oxidizable (F3, 6.89 %), and weakly acid-extracted (F1, 0.50 %) phases. Additionally, significant REY fractionations from carbonate rocks to alluvial soils were observed. The bedrock-normalized REY pattern revealed an enrichment of light rare-earth elements (LREE) and middle rare-earth elements (MREE), a depletion of heavy rare-earth elements and yttrium (HREY), and positive Ce and Gd anomalies. Secondary mineral phases that formed during weathering—such as clay minerals, oxyhydroxides, phosphates, and organic matter—played an important role in the retention and fractionation of the REY in the soils. Besides these natural factors, anthropogenic inputs also contributed to the REY fractionation, as indicated by the slight positive Gd anomaly in the karst alluvial soils. Furthermore, the differences of δCe and δEu in the soils developed from three types of pedogenic rocks—including carbonate, basalt, and granite—were discussed. The different δEu anomalies could help to identify the parent rocks of alluvial soils.

Mineralogy and geochemistry of the Middle Jurassic coal from the Hexi Mine, Shenfu Mining Area, Ordos Basin: With an emphasis on genetic indications of siderite

Siderite is a common carbonate mineral in coal and usually contains geochemical indications (elemental associations and isotopic compositions) for sedimentary environments and regional geological history, but the origin and enrichment mechanism of geochemically-pure siderite in coal is not fully understood. A better understanding of siderite origin in coal can help to decipher the depositional environment of peat and related geological processes of rank advances and epigenesis. This paper analyzed the petrological, mineralogical, and geochemical characteristics, particularly the content, occurrence, and origins of siderite in the Middle Jurassic coal from the Hexi mine of the Shenfu mining area, Ordos Basin, using optical microscopy, field emission-scanning electron microscopy, X-ray fluorescence, X-ray diffraction, inductively coupled plasma mass spectrometry, and isotope ratio mass spectrometry. The results indicate that the No. 4 Coal is rich in inertinite and is defined as an ultra-low to low sulfur, high volatile bituminous coal. Siderite has contents varying from 5.8% to 54.4% (low temperature ash basis) and occurs in radial or concentric circle nodules in the coal and is mainly distributed within the clay matrix. Syngenetic siderite in the Hexi coals is relatively pure in chemical compositions, and was formed in a brackish water environment affected by salt lakes under arid conditions. The high content of inertinite, high Sr/Cu value, and positive Ce anomaly at the uppermost of the coal seam indicate that the escalating intensification of oxidation and evaporation. The Al2O3/TiO2 ratio and the diagrams of Al2O3/TiO2 vs. Zr/ TiO2 and Al2O3/TiO2 vs. Nb/Yb indicate that the sedimentary source rock in the study area is primarily intermediate-felsic. The δ13CPDB-δ18OSMOW diagram shows C and O for the siderite formation in this study were derived from marine carbonate rock alteration of the underlying Ordovician marine carbonate rock basement. The distribution patterns of rare earth elements and Y (Middle-type enrichment and Gd anomalies) in the coal further verify this hypothesis. Furthermore, siderite in the coal exhibits an enrichment in 13C suggest that bacterial fermentation of organic matter as another possible source of CO2. The iron of the siderite in the study coal was probably derived from the leaching of the magnetite-bearing granite.

Rare earth elements in alkaline Lake Neusiedl, Austria, and the use of gadolinium microcontamination as water source tracer

The rare earth elements are increasingly used in high-tech enabling technologies and have become emerging (micro)contaminants. Their environmental impact is poorly known and regulated. Here we focus on the rare earths and yttrium (REY) systematics in Lake Neusiedl at the border between Austria and Hungary. Lake Neusiedl is the largest alkaline steppe lake in Europe and is characterised by unique and dynamic geobiological conditions. Steppe lakes, in general, are very susceptible to anthropogenic influence, as contaminants can easily accumulate under an endorheic setting. We report the first REY data for water samples from Lake Neusiedl and surrounding lakes. Lake Neusiedl shows the REY signature typical of alkaline lakes, i.e. a positive Ce anomaly and enrichment of heavy relative to light REY. More importantly, we identified prominent anthropogenic positive Gd anomalies that can be used as a water source tracer in Lake Neusiedl. The anthropogenic Gd can be tracked back to the Wulka River, one of its tributaries, and originates from medical contrast agents. As these cannot be removed from sewage during wastewater treatment, they are released into the river with the effluents from wastewater treatment plants. Additional REY data from the surrounding smaller lakes suggest that smaller amounts of anthropogenic Gd may also be present in local groundwater. We demonstrate that the anthropogenic Gd can be utilised to quantify the riverine component in Lake Neusiedl waters. However, as it reveals the presence of wastewater-derived substances in the National Park waters in general, it also hints to the potential presence of other contaminants that may have higher (eco)toxicities than the contrast agents.

Agricultural activity on the Mun River basin: insight from spatial distribution and sources of dissolved rare earth elements in northeast Thailand.

Rare earth elements (REE) are emerging pollutants of concern, impacted by intensive fertilizer use and discharge of human and animal waste into agricultural watersheds. However, the natural values and potential anthropogenic enrichment of REE in aqueous systems of the agricultural basins remain poorly understood. This study investigated the spatial variation of dissolved REE in a predominantly agricultural river (Mun River) in northeast Thailand. Dissolved ΣREE concentrations in the Mun River ranged from 5.08 to 272.91 ng/L, with the highest concentrations observed in the middle reaches where agricultural fertilizers and wastewater increased dissolved REE concentrations. The PAAS-normalized patterns and dissolved Eu anomaly jointly reveal that the dissolved ΣREE mainly originated from local rocks and agricultural fertilizers. The dissolved REE in the Mun River is characteristic of a depleted light REE relative to heavy REE, slightly negative Ce anomaly, positive Eu anomaly, and positive Gd anomaly in a punctate distribution. The correlation analysis of (La/Yb)N with fluvial pH and HCO3- indicates that the water environment characteristics of the Mun River control dissolved REE fractionation. The Ce anomaly is associated with the oxidation environment, whereas the Eu anomaly is linked to the lithologic inheritance. Positive punctate Gd anomalies are influenced by human-caused wastewater discharge and applying fertilizers, raising Gd concentrations beyond natural background levels. This study has suggested that the geochemical characteristics of dissolved REE are affected by agricultural disturbances, and future environmental research on dissolved REE is essential to clarifying the impacts of REE on agriculture, the environment, and human health.

Biomonitoring of rare earth elements in Southern Norway: Distribution, fractionation, and accumulation patterns in the marine bivalves Mytilus spp. and Tapes spp.

Growing extraction and usage of rare earth elements and yttrium (REY) for medical and industrial applications has resulted in increased discharges into the marine environment. Using Mytilus spp. Mussels and Tapes spp. clams as bioindicator organisms, we analyzed 15 REY in soft tissues of specimens collected at two potentially polluted sites in Southern Norway: in the vicinity of an industry producing gadolinium-based MRI contrast agents (GBCAs) (Lindesnes) and in an industrially-affected fjord (Porsgrunn). The spatial distribution of REY and shale-normalized fractionation patterns were determined to assess the potential anthropogenic contribution of REY at the sites. At both sites, the REY fractionation pattern in soft tissue was characterized by enrichment of light rare earth elements (LREE) over heavy rare earth elements (HREE), while also displaying negative cerium and small positive gadolinium (Gd) anomalies. LREEs contributed to over 80% of the total REY concentrations, with increasing relative enrichment following higher total REY. Gd anomalies remained conserved in most sites despite significant differences in total REY; however, a high Gd anomaly (Gd/Gd* = 4.4) was found downstream of the GBCA industry spillwater outlet, indicating biotic uptake of excess anthropogenic Gd at this site. Total REY concentrations in clams in Porsgrunn were one order of magnitude higher than in mussels in Lindesnes. This may be attributable to freshwater influences in Porsgrunn, where clams collected closer to the river mouth had significantly higher total REY concentrations. This study constitutes the first assessment of REY concentrations in marine bivalves in Norway and can provide useful information for future biomonitoring studies on REY contamination.

A craton-wide geochemical study of Neoarchaean carbonate rocks of Zimbabwe

Neoarchaean greenstone belts of the Zimbabwe craton host microbialite-bearing limestone successions that range in age from ~2.82 to 2.68 Ga. The best-preserved successions, according to Raman geothermometry, are situated in the Bulawayo and Belingwe greenstone belts where they have been subjected to lower greenschist facies metamorphism with a peak temperature of ~350 °C. Elsewhere, such as in the Masvingo belt, peak temperatures reached ~540 °C, giving rise to marbles. The carbonate rocks consist mainly of calcite and, to a lesser extent, dolomite and contain variably admixtures of siliciclastic detritus. Samples with the least amount of siliciclastic detritus have shale-normalized rare earth element and Y distribution patterns that indicate open marine conditions, with positive La, Eu, and Gd anomalies, superchondritic Y/Ho ratios, and depleted light rare earth elements relative to the heavy rare earth elements. The δ13СVPDB values are −2.0 to 2.1 ‰, and δ18OVPDB values cluster in the range of −20 to −10 ‰. Strontium isotope ratios vary in concert with siliciclastic detritus. The lowest initial 87Sr/86Sr ratio of 0.70155 is close to the depleted mantle value at the time of deposition, suggesting minimal contribution from evolved felsic crust to the Neoarchean ocean. Only samples from the Masvingo belt show radiogenic Sr isotope ratios (0.70202–0.70340) indicative of an epicratonic setting with exposed felsic basement. For the rest, open marine conditions prevailed in a proto-cratonic setting characterized by mantle-derived greenstone volcanism. Carbonate sedimentation on the Zimbabwe craton thus predate the fundamental rise in the marine 87Sr/86Sr Sr isotope signal in the late Neoarchaean.

Sedimentology and geochemistry of basinal lithofacies in the Mesoarchean (2.93 Ga) Red Lake carbonate platform, northwest Ontario, Canada

The > 200 m thick Red Lake carbonate platform of the 2.940-2.925 Ga Ball Assemblage (Red Lake Greenstone Belt, Superior Province, Canada) is the oldest known carbonate platform preserved on Earth. This study examined surface outcrops and multiple industry cored drill holes comprising a diverse assemblage of chemical and siliciclastic sedimentary rocks of the deeper water lithofacies associated with the shallow water carbonates. The offshore lithologies, underlying, interlayered with, and overlying the mainly stromatolitic carbonates, consist of alternating packages of sandstone, siltstone, carbonaceous slate, pyritic carbonaceous slate, chert, and oxide facies iron formation (OFIF). These interlayer with carbonate in transitional slope environments, which consist in places of carbonate with magnetite laminae above slumped carbonate debris in iron formation and/or carbonaceous slate. Chert and OFIF were deposited further offshore in a suboxic environment, with lithology dependent on concentrations of seawater Fe(II) and silicic acid. The iron sulfides were deposited in a reducing, anoxic, and organic-rich bottom water and muddy pore water environment not conducive to Fe hydroxide or chert precipitation. Carbonaceous mud was the background sediment, accumulating during intervals when the precipitation of chert, Fe hydroxides, or massive layers of Fe sulfides was inhibited. The interlayering of differing assemblages of chemical and siliciclastic sedimentary rocks indicates temporal and spatial fluctuations in the chemistry of local paleo-seawater and variable sedimentation rates on the margins of the Red Lake carbonate platform. Post-Archean Australian Shale (PAAS)- normalized rare earth element (REE) systematics of carbonate and OFIF show positive La and Gd anomalies, super-chondritic Y/Ho ratios, and depleted light rare earth elements (LREEs) relative to heavy rare earth elements (HREEs), similar to modern seawater, while the positive Eu anomalies in the carbonate and OFIF samples reflect hydrothermally influenced Archean seawater. The chemical sedimentary rocks exhibit enrichment of redox-sensitive elements (i.e., Cr, Mo, V, and U) compared to their siliciclastic associates. This, combined with concentrations of MnO up to 6.3 wt% and positive Ce anomalies in the iron formation directly below the carbonate platform, all indicate the likely presence of some O2 ca 2.93 Ga.

The Coorg Block, southern India: Insights from felsic and mafic magmatic suites on Mesoarchean plate tectonics and correlation with supercontinent Ur

The Coorg Block in southern India is one of the oldest crustal fragments on the globe and is composed of Mesoarchean magmatic suites, dominantly charnockites, gabbros and their variants that were metamorphosed under granulite facies conditions. Here we investigate a suite of charnockites, metagabbros and amphibolite from this block by undertaking detailed field studies, petrological and geochemical analysis, and zircon and monazite isotope geochronology. Phase equilibria modeling using pseudosection computations shows ultrahigh-temperature metamorphic conditions yielding a P-T range of 10–11 kbar at 1000 °C for the charnockite assemblage and 8–9 kbar at 950 °C for the metagabbro. Geochemistry indicates that the felsic and mafic rocks are sub-alkaline and represent a tholeiitic magma series. The rocks were derived possibly through fractionation of a reduced primary magma in a Mesoarchean subduction-related setting. Zircon grains from the charnockites and gabbros show magmatic textures, with LREE depletion and HREE enrichment, negative La, Pr, Nd, Eu and positive Ce, Sm, Gd anomalies, and Th/U ratios consistent with magmatic crystallization. We present zircon and monazite U–Pb data from a comprehensive suite of samples that indicate timing of peak of magmatic emplacement for both the charnockite and gabbroic suites occurred at ∼ 3.15 Ga, closely followed by metamorphism at ∼ 3.0 Ga. The presence of magmatic xenocrysts of up to ∼ 3.5 Ga in some of these rocks suggest older crustal components in the basement. Zircon Lu–Hf analyses suggest that the amphibolite and gabbro were mostly derived from depleted mantle sources whereas the charnockite suite involved both juvenile and reworked Paleoarchean components. The tectonic setting of these felsic and mafic magmatic rock suites correlates with a Mesoarchean subduction system, complementing recent models on the emergence of modern-style plate tectonics in the early Earth. We correlate the Mesoarchean arc magmatic suites in the Coorg Block to the building blocks of the core of the Earth’s oldest supercontinent Ur, with the surrounding Neoarchean granulite blocks and their equivalents in other cratonic fragments to the ‘expanded Ur’.

Spatial Distribution and Sources of Rare Earth Elements in Urban River Water: The Indicators of Anthropogenic Inputs

Rare earth element (REE) concentrations in river water reflect both local geological background and the intensity of anthropogenic activities. The increasing demand for high-tech applications is accompanied by an increase in REEs in water environments, especially in urban regions. Therefore, the dissolved REEs in a typical urban river (Yongding River) were analyzed to reveal the influence of anthropogenic inputs. It was found that the sum of dissolved REE (ΣREE) concentrations in river water were 6.27~86.26 ng L−1 (mean 31.05 ng L−1). The spatial distribution of REEs is significantly affected by both natural processes and human activities. To eliminate the effect of upstream land use on downstream measurements, this study established a 500 m buffer zone alongside the river and identified the anthropogenic origin of REEs through correlations among land use proportions within the buffer zone, the population density, and REEs. The Post-Archean Australian Shale (PAAS)-normalized REEs revealed pronouncedly positive Gd anomalies in the range 0.30~20.16 in all river samples. Spearman correlation analysis indicated that the proportion of cultivated land was positively correlated with most of the REEs. A three-dimensional tracer system was established via Gdanth, NO3−/Na+ and Cl−/Na+ to characterize the impact of sewage treatment plants, hospitals and agricultural activities on river water. The results indicate that with the acceleration of urbanization, abnormal REEs can be considered as a sensitive indicator to assess the influence of anthropogenic activities on water ecosystems.

Geochronology, mineralogy, and geochemistry of tonsteins from the Pennsylvanian Taiyuan Formation of the Jungar Coalfield, Ordos Basin, North China

Altered volcanic ashes occur worldwide in coal-bearing sequences. The Carboniferous is one of the important coal-forming periods but the altered volcanic ashes within coals in China of this geological age have not been well studied. In this study, the nature of the partings in the No. 9 coal seam of the Pennsylvanian Taiyuan Formation from the Yaogou Mine, Jungar Coalfield, Ordos Basin, North China, was comprehensively investigated. Fifteen partings were identified as altered volcanic ashes based on the typical features, including thin but persistent bands, sharp contacts with the enclosing coals, vermicular and book-like kaolinite, angular quartz, and euhedral primary zircons, while some muscovite and detrital zircon grains in the samples indicate minor contribution of terrigenous debris. Two UPb zircon ages from the altered volcanic ashes at the top and bottom of the No. 9 coal constrain that the Taiyuan Formation in the studied area falls within the Gzhelian Stage of the Late Pennsylvanian. All the altered volcanic ashes were defined as tonsteins due to the relative abundances of kaolinite (> 50%). Furthermore, the TiO2/Al2O3 values suggest that the tonsteins have three magmatic origins, which were mostly felsic, with less intermediate and mafic. The trace elements of the enclosing coals, detrital intra-seam clay beds, floor, and roof were mainly sourced from the felsic-intermediate rocks. However, the elevated concentrations of Li, Ga, Zr, Nb, In, Sn, Hf, Ta, Pb, and Th may be related to the leaching of the tonsteins by (acidic) groundwater or hydrothermal solutions. This is supported by the dominant MREY enrichment patterns with positive Gd anomalies of the coals.

キレート樹脂固相抽出法を併用したICP質量分析法による下水処理施設周辺環境水の超高感度多元素分析

Analytical method for the determination of major-to-ultratrace elements in environmental water samples around sewage treatment plant by ICP-MS was examined in detail. In the present work, solid phase extraction using chelating-resin was adopted as the preconcentration method for the determination of ultratrace elements. Prior to solid phase extraction, environmental water samples were heated with nitric acid and hydrogen peroxide at 200 °C for 4h to decompose chelating agents contained in sewage effluent such as EDTA, which cause low recovery values for several elements. As a result, 53 elements in the concentration range from sub-ng/L to several 10 mg/L could be determined with good reproducibility. The reliability of the whole analytical procedure was confirmed by analyzing river water certified reference materials (JSAC 0301-4a and JSAC 0302-4a). From the analytical results for environmental water (river water) samples around sewage treatment plant (upstream, just below outlet, downstream 1 and downstream 2), it was found that various elements such as Fe, Co, Ni, Cu, Zn, Cd, and Pb were emitted from sewage effluent into environmental water (river water) as dissolved forms, while the element existed mainly in particulate matters (Al, Ti, and rare earth elements) showed low concentrations in sewage effluent. Distribution patterns of rare earth element for sewage effluent and downstream samples showed characteristic large Gd anomalies and increase from light REE to heavy REE, which were the same as other environmental water samples affected by the influx of sewage effluent.

Geochemistry and Mineralogy of Paleocene Coal from the Padhrar and Darra Adam Khel Coalfields of Pakistan

AbstractPakistan is rich in coal resources, which amount to around 186 billion tons. The Paleocene Padhrar and Darra Adam Khel coalfields are located in the Central Salt Range Punjab Province and the Khyber Pakhtunkhwa Province, Pakistan, respectively. Padhrar coal has not been studied in detail and the Darra Adam Khel coalfields are newly‐discovered, so no research has been done, due to security considerations. In this study, an attempt has been made to study the geochemical and mineralogical characteristics of the Padhrar and Darra Adam Khel coals, in order to learn about the coal quality, element enrichment mechanism, sedimentary medium conditions and potentially valuable elements for coal utilization. The Padhrar and Darra Adam Khel coals are low to medium ash, low moisture content, high in volatiles and high total sulfur coal. The vitrinite reflectance in Darra Adam Khel coal is higher than in Padhrar coal, indicating either a greater burial depth or the effects of Himalayan tectonism. The vitrinite content is dominant in the Padhrar and Darra Adam Khel coals, followed by inertinite and liptinite, the major minerals including quartz, clay minerals, calcite and pyrite. The trace elements Ni, As, Be Zn, Ge, Mo, Ta, W, Co and Nb, Sn, Hf, Ta, Pb, Th, Cd, In, Be, V, Cr, Zr, Ag, Li, W and Co are concentrated in some of the Padhrar and Darra Adam Khel coal samples, respectively. The Padhrar coal shows positive Ce, Eu and Gd anomalies, with most of the Darra Adam Khel coal showing negative Ce, Eu and positive Gd anomalies with high LREE. The Al2O3/TiO2 values indicate that the sediment source of the Padhrar and Darra Adam Khel coals is mostly related to intermediate igneous rocks. The Sr/Ba, SiO2 + Al2O3, Fe2O3 + CaO + MgO/SiO2 + Al2O3 and high sulfur content in the Padhrar and Darra Adam Khel coals indicate epithermal and marine water influence with a tidal flat, coal‐forming environment and a deltaic coal‐forming environment, respectively.

Rare earth elements and yttrium in suspension-feeding bivalves (dog cockle, Glycymeris glycymeris L.): Accumulation, vital effects and pollution

Rare earth element (REE) and Y (REY) concentrations were determined in soft tissues and shells prepared from 9 to 93 years old dog cockles sampled alive from a marine site in NW Brittany, France. The concentrations shown by the different soft tissues and shells are extremely variable ranging from 9·10−5 to 10−1 × PAAS. The mantle is the organ with the highest concentrations, while the feet, the adductor muscles and the digestive glands display the lowest ones. Relative to the masses of the different organs, we show that the shell concentrates >85% of the REY contained in an animal, and the mantle, which represents less than 0.5% of the total animal mass (on a dry basis), contains 10% of the total REY. Organs accumulate REY throughout the life of the animal. REY concentrations in soft tissues increase by more than one order of magnitude in 90 years. The shells mirror the REY abundances of the mantle but are slightly less light-REE enriched than the latter. Furthermore, shells as well as feet and adductor muscles show a striking correlation between animal age and Ce/Ce* ratios. Ce/Ce* ratios evolve from 0.8 for animals aged ∼10 years to 1 for the oldest, with most of the variation during the first 25 years, indicating that Ce also accompanies biochemical reactions probably related to the growth or maturity of the animals.Soft tissues also show extremely variable positive Gd anomalies (Gd/Gd*= 1.04–1.94) which indicate environmental pollution by Gd based contrast agents (GBCA) used in medical imaging. Anomalies tend to be more important for organs poor in REY (like muscles and digestive glands). Low excesses of Gd, on the order of 1–3 ng/g (on a dry basis), account for these anomalies. There is no correlation between the age of the animals and the amount of anthropogenic Gd or Gd/Gd* ratios suggesting that GBCAs do not accumulate in the bivalve body on a long-term basis.

Geochemistry of the Neoarchean Dodguni carbonates of Chitradurga greenstone belt, Dharwar Craton, India: Implications on depositional environment

The carbonates of the Dodguni area of the Chitradurga greenstone belt, Dharwar Craton, India were studied to understand the Archean diagenetic and palaeo‐depositional conditions using carbon and oxygen isotopes along with whole‐rock geochemistry. These carbonates show significant variation in δ13C and δ18O (−1.73‰ Vienna Peedee Belemnite [VPDB] to −0.45‰ VPDB and δ18O vary from −13.51‰ VPDB to −8.46‰ VPDB, respectively). The rare earth element (REE) + Y (rare earth elements and yttrium) of the studied carbonate rocks exhibit flat and uniform patterns (PrSN/YbSN = 0.4–1), slight positive La, Eu and Gd anomalies (CeSN/CeSN* = 0.8–0.9; EuSN/EuSN* = 0.7–1.4 and GdSN/GdSN* = 2–2.3, respectively) with slight positive Ce anomalies (PrSN/PrSN* = 0.84–0.86) and superchondritic Y/Ho ratios (Y/Ho = 29–45; chondritic Y/Ho = 28). Their negative δ13C (−1.75‰ to −0.45‰) values are attributed to the influence of higher bio‐productivity during their deposition and oxidation of organic carbon. The geochemical and isotopic systematics suggest that the Dodguni limestones are not affected by the diagenetic and metamorphic processes and record the REE geochemistry of the ancient seawater in which they were precipitated. The comprehensive geochemical including the isotopic studies of the Archean carbonate rocks of the Dharwar Craton, indicate their deposition in shallow marine conditions, precipitation in high temperatures with significant hydrothermal input under the influence of high bio‐productivity, thereby providing valuable constraints on the palaeoceanography and geochemical evolution of the Archean sea.