Variations of trace elements and rare earth elements(REEs)treated by two different methods for snow-pit samples on the Qinghai-Tibetan Plateau and their implications

Although previous investigations of the trace elements in snow and ice from the Qinghai-Tibetan Plateau obtained interesting information about pollution from human activities on the plateau, most were based on traditional acidification methods.To emphasize the influence of the different sample-preparation methods on the records of trace elements and rare earth elements, snow samples were collected from glaciers on the Qinghai-Tibetan Plateau in China and prepared using two methods: traditional acidification and total digestion. Concentrations of 18 trace elements(Al, Ti, Fe, Rb, Sr, Ba, V, Cr, Mn, Li,Cu, Co, Mo, Cs, Sb, Pb, Tl, and U), along with 14 rare earth elements(REEs: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,Tm, Yb, and Lu), Y, and Th in the snow samples, were measured using inductively coupled plasma-sector field mass spectrometry(ICP-SFMS). The results showed that the mass fraction of the trace elements(defined as ratio of concentration in the acid-leachable fraction to that in the digested sample) such as Mo, Ti, Al, Rb, and V, varied from 0.06 to 0.5. The mass fraction of other trace elements varied from about 0.6 to more than 0.9; those of the REEs, Y, and Th varied from 0.34 to0.75. Lower mass fractions will lead to an overestimated contribution of other sources, especially human activities, and the underestimated fluxes of these trace elements(especially REEs, Y, and Th, as well as dust) if the REEs are used as the proxy for the crust dust. The two sample-preparation methods exhibited different REE normalized distribution patterns,REE ratios, and provenance-tracing results. The REE normalized distribution patterns and proxies in the digested samples are more reliable and integrated than those found in traditional acidification method for dust-provenance tracing.

Geochemical Characteristics of the Trace and Rare Earth Elements in Reef Carbonates from the Xisha Islands(South China Sea): Implications for Sediment Provenance and Paleoenvironment

Based on the concentrations of the trace elements,rare earth elements(REE),and Sr isotopic compositions in reef carbonates from the well‘Xike-1’reef core of the Xisha Islands,the constraints on sediment provenance and paleoenvironment were defined.Variations of the terrigenous input into the paleoseawater were traced in detail and the paleoenvironment and sediment provenance were further investigated.The results show that the HREE/LREE values in the reef carbonates are negatively associated with their Th and Al concentrations;however,their Al and Th concentrations show positive correlation.The lowest 87 Sr/86 Sr values in the reef carbonates generally coincide with the lowest values of Al,Th concentrations and the highest values of HREE/LREE.These data indicate that the HREE/LREE,Al concentrations,and Th concentrations of the reef carbonates are useful indexes for evaluating the influence of the terrigenous inputs on the seawater composition in the study area.From top to bottom,the changing process of the HREE/LREE values and Al,Th concentrations can be divided into 6 intervals;they are H1(0–89.30 m,about 0–0.11 Myr),L1(89.30–198.30 m,about 0.11–2.2 Myr),H2(198.30–374.95 m,about 2.2–5.3 Myr),D(374.95–758.40 m,about 5.3–13.6 Myr),L2(758.40–976.86 m,about 13.6–15.5 Myr),and H3(976.86–1200.00 m,about 15.5–21.5 Myr).Moreover,the changing trend of the HREE/LREE values coincides with that of the seawater δ^13C values recorded by benthonic foraminiferal skeletons from the drill core of ODP site 1148 in the South China Sea(SCS),but not with that of the seawaterδ18O values.The high uplifting rates of the Qinghai-Tibet Plateau coincide with the high Th and Al concentrations and the low HREE/LREE values in the reef carbonates.These data indicate that the main factors controlling the changes of terrigenous flux in the SCS are the tectonic activities associated with Qinghai-Tibet Plateau uplifting and the variations of uplifting rates rather than paleoclimatic changes.

Trace and Rare Earth Element Geochemistry of Micrite Mound Carbonates and Other Related REE Mineralized Carbonates from Bayan Obo Area in Inner Mongolia

Geochemical study on trace and rare earth element geochemistry was carried out for different carbonates including the very REE-rich ones in the main ore bodies, a carbonatite dyke and two micrite mounds from Heilaobao far away from the Bayan Obo ore deposit, and Xishan in west Beijing. The results show that both carbonatite dyke and REE mineralized carbonates (dolomite and marble) in the main ore bodies and outside ore bodies have similarities to each other, with very extreme positive anomaly of Ba, Th, Nb, La, Ce, Nd, Sm, Pb, medium positive anomaly of Y, Ho, Tb, Er, Yb and negative anomaly of Sc, Ti and Cu. The REE concentration in the mineralized carbonates changes greatly, the total REE content changes from 262×10^(-6) in both east and west ore deposits to 104562 ×10^(-6) (10.46%), which is relatively lower than those samples of carbonatite dyke, whose REE contents vary greatly, from 1% up to 20 % of mass fraction. Light REE in the carbonatites are enriched and highly fractionated relative to heavy REE and there is no Eu anomaly. The REE distribution patterns of both mineralized carbonate and carbonatite dyke are of some similarities. However, the sedimentary carbonate micrite of Salinhudong Group in Heilaobao far outside the ore bodies and the pure carbonates from Xishan in Beijing, central part of North China plate, have the similarities in REE distributions with much lower REE contents, which are significantly different from those of carbonatite dyke and REE mineralized carbonate. In Bayan Obo district, both carbonates in the ore deposit and micrite mound outside the ore deposit underwent widespread metasomatism by fluids that resulted in formation of the superlager Fe-Nb-REE mineralization. It appears that the carbonates represent the evolution products of different geological stages.

Adsorption experiment of water-soluble rare earth elements in atmospheric depositions and implications for source tracing in South China

The distribution patterns of rare earth elements(REEs)in fine-grained materials in various depositions were often found to be similar to those of the aeolian sediments deposited in the Loess Plateau in North China and the fine-grained materials were suggested to be derived from wind-blown dust.However,increasing evidence indicated that the REEs in the water-soluble portion of atmospheric depositions also displayed similar patterns to those of aeolian sediments.In this study,water-soluble REEs in three atmospheric depositions collected from different climatic zones in China were adsorbed with two adsorbents with distinct adsorption capacity,glass powder,and co-precipitated iron hydroxide.The results showed that the REEs adsorbed by the two adsorbents displayed patterns similar to those of the original atmospheric depositions.The typical characteristics of the REE patterns of atmospheric deposition can be well reproduced in the adsorbed REEs.The higher the REE concentrations in the atmospheric depositions,or the higher adsorption efficiency of the adsorbents,the better reproducibility of the REEs patterns.The results suggest that the REEs of the fine-grained materials in various sediments,which have a high adsorption capacity,especially those deposited in South China,may come from the water-soluble REEs in atmospheric deposition,and may not be appropriate tracers of wind-blown dust from North China.

Zircon deposit and rare earth element enriched metasomatic alkaline rocks at Kyemyeongsan Formation, Chungju, Korea: Paleozoic magmatism and Zr-REE-Nb mineralization

The zircon ore deposit in metasediments and peralkaline granite of the Kyemyeongsan Formation is located in southwest of Chungju city, Korea. The deposit, closely associated with REE and Nb,is composed of metasomatic alkaline rocks and rare metal alkali granite, and was formed in late Carboniferous (340～343Ma). Zircon occurs in different paragenetic sequence: (1) earlier rare metal alkali granite, (2) later metasomatic zircon ore. The metasomatic zone contains abundant microcline, albite and quartz with minor biotite, magnetite, hornblende, allanite and zircon. The alkali granites have high silica (72.13～74.52wt.% as SiO 2), and total iron content (5.95～6.89%), and are characterized by low Al 2O 3 content (7.12～9.74%). They also show variable K 2O content (3.60～6.98%), and high ratios of K 2O/Na 2O. The REE patterns of rare metal alkali granite are similar to those of felsic volcanics from rifts, or back arc basins in, or near continental crust. Zircon ores are characterized by high iron content and low Al 2O 3, SiO 2, and K 2O content and have unusually high total REE content (0.18～2.33%). REE patterns show relatively flat to somewhat heavy REE (HREE) depleted characteristics (Ce/Yb=0.39～5.17) with large Eu negative anomaly (Eu/Eu *=0.16～0.29). Laser ablation microprobe inductively coupled plasma mass spectrometer (LAM ICP MS) analyses has been carried on zircon. The REE patterns of mineral zircons are almost the same to those of zircon ores and rare metal alkali granites, which may reflect the inability of zircons to effectively fractionated REE at formation of origin. The Sm Nd isochron age of the zircon ore and rare metal alkali granite are 330Ma, and 331Ma, respectively with ε Nd(t) being range from -2.00 to -1.84. This data suggest that the ore forming material came from the mantle. Alkali granite has suffered extensive post magmatic metasomatism of a high temperature to produce zircon ores. Geochemical characteristics show that metasomatism of alkaline fluid was probably the dominant ore forming process in Chungju district.

Trace Elements and Rare Earth Elements of Sulfide Minerals in the Tianqiao Pb-Zn Ore Deposit,Guizhou Province,China

Trace elements and rare earth elements（REE） of the sulfide minerals were determined by inductively-coupled plasma mass spectrometry.The results indicate that V,Cu,Sn,Ga,Cd,In,and Se are concentrated in sphalerite,Sb,As,Ge,and Tl are concentrated in galena,and almost all trace elements in pyrite are low.The Ga and Cd contents in the light-yellow sphalerites are higher than that in the brown and the black sphalerites.The contents of Ge,Tl,In,and Se in brown sphalerites are higher than that in light-yellow sphalerites and black sphalerites.It shows that REE concentrations are higher in pyrite than in sphalerite,and galena.In sphalerites,the REE concentration decreases from light-yellow sphalerites,brown sphalerites,to black sphalerites.The ratios of Ga/In are more than 10, and Co/Ni are less than 1 in the studied sphalerites and pyrites,respectively,indicating that the genesis of the Tianqiao Pb-Zn ore deposit might belong to sedimentary-reformed genesis associated with hydrothermal genesis.The relationship between LnGa and LnIn in sphalerite,and between LnBi and LnSb in galena,indicates that the Tianqiao Pb-Zn ore deposit might belong to sedimentary-reformed genesis.Based on the chondrite-normalized REE patterns,δEu is a negative anomaly（0.13-0.88）,andδCe does not show obvious anomaly（0.88-1.31）;all the samples have low total REE concentrations（〈3 ppm） and a wide range of light rare earth element/high rare earth element ratios（1.12-12.35）.These results indicate that the ore-forming fluids occur under a reducing environment.Comparison REE compositions and parameters of sphalerites,galenas,pyrites,ores,altered dolostone rocks,strata carbonates,and the pyrite from Lower Carboniferous Datang Formation showed that the ore-forming fluids might come from polycomponent systems,that is,different chronostratigraphic units could make an important contribution to the ore-forming fluids.Combined with the tectonic setting and previous isotopic geochemistry evidence,we conclude that the ore-deposit genesis is hydrothermal,sedimentary reformed,with multisources characteristics of ore-forming fluids.

Rare Earth Element and Trace Element Features of Gold-bearing Pyrite in the Jinshan Gold Deposit,Jiangxi Province

Jinshan gold deposit is located in northeastern Jiangxi,South China,which is related to the ductile shear zone.It has a gold reserve of more than 200 tons,with 80%of gold occurring in pyrite. The LREE of gold-bearing pyrite is as higher as 171.664 ppm on average,with relatively higher light rare earth elements（LREE;159.556 ppm） and lower HREE（12.108 ppm）.TheΣLREE/ΣHREE ratio is 12.612 and（La/Yb）_N is 11.765.These indicate that pyrite is rich in LREE.The（La/Sm）_N ratio is 3.758 and that of（Gd/Yb）_N is 1.695.These are obvious LREE fractionations.The rare earth element（REE） distribution patterns show obvious Eu anomaly with averageδEu values of 0.664,andδCe anomalies of 1.044.REE characteristics are similar to those of wall rocks（regional metamorphic rocks）,but different from those of the Dexing granodiorite porphyry and Damaoshan biotite granite.These features indicate that the ore-forming materials in the Jinshan gold deposit derived from the wall rocks, and the ore-forming fluids derived from metamorphic water.The Co/Ni ratio（average value 0.38） of pyrite suggests that the Jinshan gold deposit formed under a medium-low temperature.It is inferred from the values of high-field strength elements,LREE,Hf/Sm,Nb/La,and Th/La of the pyrite that the ore-forming fluids of the Jinshan gold deposit derived from metamorphic water with Cl〉F.

Electronic Theoretical Study of the Interaction between Rare Earth Elements and Impurities at Grain Boundaries in Steel

The model of dislocations was used to construct the model of grain boundary (GB) with pure rare earths, and rare earth elements and impurities. The influence of the interaction between rare earth elements and impurities on the cohesive properties of 5.3° low angle GB of Fe was investigated by the recursion method. The calculated results of environment sensitive embeding energy( E ESE ) show that the preferential segregation of rare earth elements towards GBs exists. Calculations of bond order integrals (BOI) show that rare earth elements increase the cohesive strength of low angle GB, and impurities such as S, P weaken the intergranular cohesion of the GB. So rare earth element of proper quantity added in steel not only cleanses other harmful impurities off the GBs, but also enhances the intergranular cohesion. This elucidates the action mechanism of rare earth elements in steel from electronic level and offers theoretical evidence for applications of rare earth elements in steels.

Jurassic Black Shales Facies from Qiangtang Basin (Northern Tibet): Rare Earth and Trace Elements for Paleoceanographic Implications

The Biluo Co and Amdo 114 station, northern Tibet, cropping out the Early Toarcian and Middle-Late Tithonian （Jurassic） organic-rich black shales, have been a focus to petroleum geologists in discussing their oil-producing potential. This paper first reports the trace elements and rare earth elements to discuss the paleoenvironments, redox conditions and sedimentary mechanisms of those black shales. Both sections exhibit variation in trace element abundances with concentrations 〈0.1 ppm to 760 ppm, mostly enriched in V, Cr, Ni, Cu, Zn, Mo, Ba and U. Element ratios of Ni/Co, V/Cr, U/Th and V/（V＋Ni） plus U were used to identify redox conditions. The shale-normalized rare earth element （REE） patterns are characterized by the flat-shale type with instable Ce anomalies and very weekly positive Eu anomalies. Positive Ceanom values are significant with values varying between - 0.064 and 0.029 in Biluo Co, which may be interpreted as release of REE and input of riverine terrestrial matter with rich Ce （resulting in pH change） during the anoxic conditions. In the middle parts of Amdo 114 station, distinct negative Ceanom values are observed （-0.238 to -0.111） and associated surface water warming were interpreted as being related to a major sea level rise. In contrast, the formation of the black shales in the lower and upper part of the studied succession took place during a cooler （Ceanom values 〉-0.10）, lower surface water productivity, and lower sea-level stage. Thus, we emphasize the role of different factors that control the formation of local and regional black shales. The most important factors are sea-level fluctuations and increasing productivity.

Rare Earth Elements in Zhijin Phosphorite and Distribution in Two-Stage Flotation Process

Zhijin phosphorite is one of super large-scale medium-low grade and REE-bearing phosphorite deposit in Southwest of China. Previous investigations had revealed that this deposit contained appreciable amounts of rare earth elements (REE) reaching up to 1300 μg·g-1. In this paper, REE contents and existing state in single collophanite and dolomite mineral were further analyzed by ICP-MS and EPMA-1600 Electric Probe methods. The results indicated that REE content of collophanite was far more than that of dolomite, and increased with an increase of phosphor. There existed independent minerals of REE in single collophanite mineral, such as cerianite and monazite, but the amount of them was extremely little. No independent mineral of yttrium was found in this investigation. Presumedly, REE and yttrium were present in the form of ions in the lattices of collophanite. Based on above investigation, the two-stage reverse flotation technology was carried out to see the distribution of REE in flotation process. It was found that REE was mainly enriched in phosphate concentrate and recovered in the rough stage flotation. REE recovery of concentrate increased with an increase of P2O5 content and P2O5 recovery of concentrate. Under the optimum flotation condition, REE recovery was 79.25% in the rough stage flotation and 9.94% in scavenging flotation.

Rare Earths, Trace Element Characteristics of High-Mg Volcanic Rocks of Yixian Formation in Sihetun West Liaoning Province and Its Apocalypse

The high-Mg volcanic rocks of the Yixian Formation in the Sihetun area have the obvious characteristics of mantie-derived lava in rare earth, trace element characteristics with high Mg # （62 - 70） and high content of compatible elements. In the meantime, the volcanic rocks also have the obvious characteristics of Crust-source material in rare earth, trace element characteristics with high ∑ REE （ 158.78 × 10^-6 - 359.66 × 10^-6 ）, high （La/Yb） N （ 14.61 - 29.60）, high La/Nb（2.37 - 7.52） and high Ba/Nb （67.58- 205.96）, obvious positive anomaly of Pb and negative anomaly of Nb, Ta in trace element spider-gram. In Sr-Nd-Pb isotope the （^87Sr/^86Sr）i ratio is higher than 0.706 and the εNd（ t ） ratio is from - 3.4 to - 13, both reflect enriched Mantle characteristics. The characteristics above of the volcanic rocks combined with the content of Sr, Ba, Y, Yb and the ratio of Sr/Y show that the volcanic rocks have the property of the Sanukite rocks in Setouchi Japan beside subduction zone, and illuminate that the Sanukite rocks can be formed not only in island-arc near subduction zone but also in intro-plate. The analysis indicates that the high-Mg volcanic rocks in the Sihetun area result from the collective function of mantle-derived lava and crust-source materials. The result illuminates that the West Liaoning region is very special in tectonic geochemical background in Cretaceous in East China, and is an ideal region for us to further study the characteristics of magmatic activity as well as the process of Crust-Mantle interaction in Eastern China.

Geochemical Features of Trace and Rare Earth Elements of Pumice in Middle Okinawa Trough and Its Indication of Magmatic Process

Pumice,the most widely distributed volcanic rock in Okinawa Trough,is loose and porous.Since its formation,it has definitely suffered from the denudation of the sea to different degrees.In order to truly reveal the geochemical features of pumice,we choose the method of mineral separation.Firstly,the phenocryst is separated from glass.Then the phenocryst is divided into light and heavy mineral compositions.By ICP-MS(inductively coupled plasma mass spectrometry) analytical technology,the contents of trace and rare earth elements in the whole pumice,the glass and the heavy and light mineral compositions are determined respectively.By researching the elemental geochemical features,the magma dynamic processes are found.It shows that the initial magma for the pumice in Okinawa Trough came from the depleted mantle,from which the N-MORB(normal type of mid-ocean ridge basalt) is formed,homologous with the local basalts.But they are formed in different periods of magma crystal fractionation.Featured with sufficient crystal fractionation for pumice,it is found that the earlier crystallizing minerals are olivine,plagioclase and pyroxene.The pumice magma,formed from the depleted mantle,was mixed with additional subduction-related materials(components),and contaminated with the mass from upper crust when it rose up into the crust.As the Okinawa Trough is a back-arc basin in its early back-arc spreading stage,its magmatism has a series of its own unique characteristics,different from not only the mid-ocean ridge expansion,but also the mature back-arc basin.

Effect of Long-term Intake of Rare Earth in Drinking Water on Trace Elements in Brains of Mice

The mice were fed with water dissolved different level Y 3+ (0, 23.25, 2325.00 mg·L -1 ) for seven months, and the levels of trace elements such as Cu, Zn, Mn, Fe, Mg, Ni and Co in brains of F1 generation mice were then determined by POEMS. The results show that, compared with control, significant decreases in levels of Fe and Ni, increase in level of Co are observed, which suggested that Y 3+ may have an effect on the metabolism and distribution of some trace elements in brain, and then lead to changes of physiological function.

Bioleaching of trace elements and rare earth elements from coal fly ash

Coal fly ash originated from coal combustion has high concentrations of metals. If suitable leaching techniques are identified, then coal fly ash could serve as a useful source of valuable minerals including rare earth elements (REEs). In this study, three microbial strains, Candida bombicola, Phanerochaete chrysosporium and Cryptococcus curvatus were tested on their performance of leaching trace elements and REEs from fly ash. Through comparing mineral loss and leaching efficiencies resulting from indirect leaching or use of the culture supernatant, C. bombicola was identified to be the best leading to the highest mineral loss and extracting efficiencies of trace elements and REEs among the three strains. The highest mineral loss observed from using the supernatant of this yeast strain was 59.7%. Among all trace elements, As and Mo had the highest leaching efficiency of 80.9% and 79.5%. respectively. The same leaching test led to 67.7% of Yb and 64.6% of Er dissolved from the ash. This study, thus, demonstrated that bioleaching is feasible for leaching metals out of fly ash. The C. bombicola strain deserves further investigation due to its robust actions on metal leaching.

Rare earth element content in the SPM of Daliao river system and its comparison with that in the sediments, loess and soils in China

Content and distribution patterns of rare earth dements （REEs） in the suspended particulate material （SPM） of Daliao River system were investigated and compared with those in the fiver and sea sediments, loess, and soils of China. Twenty-seven samples of SPM were taken in Daliao River system and digested with various acids followed by ICP-MS analysis for REEs and ICP-OES analysis for Al, Fe, Mn, Ti, Mg, Ca, Na, and K, to measure the total concentrations of these elements. Results indicated that the spatial change in the content of REEs was great, with the coefficient of variance （CV） from 84% to 105%, while the contents of REEs were significantly correlated with each other. Chondrite-normalized patterns of REEs were characterized by higher enrichment of light REEs than heavy REEs, and a depletion of Eu in the SPM was generally found. The positive anomaly of Eu in the SPM of Xi River was due to anthropogenic source in Shenyang City. Furthermore, chondfite- and upper continent crust-normalized patterns of REEs in the SPM of Daliao River system, sediments of Yangtze River and Yellow River, sediments of Yellow Sea, East Sea, South Sea of China, and loess and soil of China, were very similar to one another. These demonstrated that the weathering and sedimentary processes resulted in constant REE distribution not only in the typical sedimentary rocks, but also in the modem riverine particle, sea sediments, loess, and soils.

Simultaneous Determination of Trace Rare Earth Elements and Other Elements in High Purity Terbium Oxide (Tb_4O_7) by ICP-AES After HPLC Separation Using P507 Resin

This article describes a new method for the simultaneous determination of trace rare earth elements (REEs) and non rare earth elements (NREEs) in high purity terbium oxide by ICP-AES after HPLC separation using P507 resin. The chromatographic separation of the analytes from the matrix using dilute nitric acid as mobile phase was studied. The experimental results showed that a favorable separation of trace metals (Cu and Gd) from the matrix (Tb) can easily be achieved by elution with dilute nitric acid within 25 min. The proposed method was applied to the determination of trace metals (Ca, Cu, Mg, Mn, Ni, Si, La, Ce, Pr, Nd, Sm, Eu and Gd) in high purity terbium oxide. The detection limits (DLs) for the analytes ranged from 0.4-4.0 μg\5g -1, and the recoveries are from 78%-105%.

Geochemistry of rare-earth elements in shallow groundwater, northeastern Guangdong Province, China

Shallow groundwater and hot springs were collected from northeastern Guangdong Province, Southeast China, to determine the concentrations and fractionation patterns of rare-earth elements(REE). The results show that the La, Ce and Nd of REEs are abundant in groundwater and rock samples, and the ∑REE contents in groundwater and rock samples range from 126.5 to 2875.3 ng/L, and 79.44 to 385.85 mg/L, respectively. The shallow groundwater has slightly HREE-enriched PAAS-normalized patterns. However, the granitic rocks PAAS-normalized patterns, with remarkable negative Eu anomalies, are different from that of shallow groundwater. The enrichment of HREE is considered to be controlled by REE complexation and readsorption for most groundwater has Ce and Eu positive anomalies. The Ce and Eu anomalies in groundwater are controlled by redox conditions. Moreover, the Fe-contain sediments dissolution and/or the reduction of Fe oxyhydroxides are another factor contributing to Ce anomalies. The Eu anomalies in groundwater are controlled by the preferential mobilization of Eu2+ during water-rock interaction compared to Eu3+.

Multi-Trace Element and Rare Earth Element Composition of Coastal Casuarina Equisetifolia Ecosystem in Hainan Island,China

46 trace elements including 14 rare earth elements (REEs) in coastal Casuarina equisetifolia plant-soil system from 9 sampling sites in Hainan Island were detected by using ICP-MS. The aim is to explore the biogeochemical characteristics of migration and translocation of trace elements in soil-plant system and their function on the changes of environmental geochemistry. The results indicate that multi-trace elements in coastal sandy soil in Hainan Island are at very low level. The multi-element patterns are quite similar among plant,sandy soil and upper continental crust (UCC),and the magnitudes of trace element concentrations among them are different in the general order of plant<soil<UCC. Sandy soil has trace element concentrations with 1～2 orders of magnitudes less than those of the average UCC,while plant has 1～3 orders of magnitudes less than UCC and 1～2 orders less than the soil. The total trace element contents are not significantly different between root and needle,but significantly different between branch and root and between branch and needle. Those of root or needle are about 2 times of those of branch. Ag,Cd,In,Sn and Tl are enriched in C. equisetifolia,especially Ag.

Determination of Trace Impurities of Rare Earth Elements in High Purity Yttrium Oxide by ICPMS

Determination of trace rare earth elements(REEs)in 99. 999% purity yttrium oxide using the inductively coupled plasma mass spectrometric technique (ICPMS) has been developed. Instrumental parameters and factors affecitng analytical results have been studied and then optimized.Samples are analyzed directly following an acid digestion without separation or preconcentration and with limit of detection of 0. 003～0. 02 ng/ml, precision of ±5. 4%(cofficient of variation)and recovery of 90～115%. Correction for isobaric interferences from oxide ions and hydroxide ions is made mathematically. Special internal standard procedures are used to compensate drift in metal:metal oxide ratios and sensitivity. The analytical results of several samples are accurate as compared with inductively coupled plasma atomic emission spectrometry (ICPAES) and spark source mass spectrometry (SSMS).

Distribution pattern and geochemical analysis of rare earth elements in deep-ocean sediments

The content and distribution pattern of rare earth elements(REEs)in surface sediments from the Eastern and Western Pacifi c Ocean,the Northern and Southern Atlantic Ocean,and the Southwestern Indian Ocean were explored and the resources and geochemical characteristics of REEs in deep-ocean sediments from diff erent oceans were studied.The total REE abundances(ΣREE)in the diff erent oceans ranged as follows:Eastern Pacifi c,56.88–500.02μg/g;Western Pacifi c,290.68–439.94μg/g;Northern Atlantic,55.33–154.90μg/g;Southern Atlantic,40.83–69.30μg/g;and Southwestern Indian Ocean,20.24–64.76μg/g.Their corresponding LREE(La-Eu)/HREE(Gd-Lu)average values were 5.18,5.86,9.01,5.21,and 4.59,which indicated that the light REEs were all evidently enriched.δEu andδCe showed slight Eu-negative anomalies and signifi cant Ce-positive anomalies in all sediments.Although the contents of REEs in the sediments varied among the diff erent oceans,the distribution patterns of REEs were similar,and the correlation coeffi cient was greater than 0.9290.In the Eastern Pacifi c sediments,ΣREE showed a signifi cantly positive correlation with Co,Cu,Zn,Mn,Mo and a weak correlation with Fe.In the Western Pacifi c and Southern Atlantic sediments,ΣREE presented no obvious correlation and a weakly negative correlation with Co,Cu,Zn,Mn,Mo and Fe,respectively.ΣREE in the Southwestern Indian Ocean sediments positively correlated with Cu,Zn,Mn,Mo,Fe,and had a weakly negative correlation with Co.