ABSTRACT
The concentrations and distributions of trace metals and rare earth elements (REE) in sediment and mussel samples collected from the India Ocean hydrothermal area were analyzed.The metal correlation between organisms and sediments was investigated, and the ecological and chemical characteristics of REE were also explored.The results showed that, the trace metals in sediments were mainly Fe (96.6 mg/kg), Mn (1.14 mg/kg) and Zn (322.6 μg/kg), and Fe had high ratio of 98.15% by normalized calculation, which indicated that the available sediments in this studying hydrothermal area mainly consisted of iron ore substances.Trace metals and REE distributions all had good correlation between deep-sea sediments and deep-sea mussels, and the correlation coefficients were 0.991 for trace metals and 0.996 for REE.The contents and distributions of metal elements in deep-sea mussels were different from those in offshore mussels.The REE distributions in sediments and mussels showed obvious fractionation phenomenon, and the enrichment of LREE in mussels was significant.Through the REE patterns, Eu and Gd in sediments and mussels all showed anomalies, and Eu had a significant abnormal phenomenon in deep-sea sediments and deep-sea mussels.Besides, δEu values were 9.50, 10.68 and 0.23 in deep-sea sediments, deep-sea mussels and offshore mussels, respectively, and δCe were 2.21, 2.71 and 4.38, which showed that the enrichment sources of REE in offshore mussels and deep-sea mussels were different, and the REE in sediments and mussels from the India Ocean were homologous.
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A total of 30 kunds of fush samples, 5 kunds of shellfush samples and 4 kunds of crustacean samples from the Nansha sea area of chuna were dugested by mucrowave dugestuon system wuth HNO3-H2 O2 as the dugestuon reagent. Then the contents ( ICP-MS determunatuon) and ecologucal chemucal characterustucs of rare earth elements ( REE) were studued. The results showed that the method of mucrowave dugestuon-ICP-MS for the determunatuon of rare earth elements was perfect, and the lunear relatuonshup for each element was good wuth r≥0 . 9997 . The detectuon lumut of the method could reach 1 . 0 ng/L wuth the relatuve standard devuatuon (RSD, n=3) of less than 5. 0%. The recoverues of rare earth elements were between 91. 50% and 106. 67%. The total amount of rare earth un fush samples, shellfush samples and crustacean samples were 5. 02-34. 8 μg/kg, 30. 4-1481 μg/kg and 103-863 μg/kg, respectuvely. The average enruchment contents of the rare earth un the 3 specues was crustacean > shellfush > fush. The contents of 14 rare earth elements un fush/shellfush/crustaceans showed sugnufucantly posutuve correlatuon ( r>0 . 80 ) . The contents of lught rare earth elements ( La-Eu) were hugher than that of heavy rare earth elements ( Gd-Lu) . The lught and heavy rare earth elements had obvuous fractuonatuon, and the REE dustrubutuon pattern was consustent un fush/shellfush/crustacean wuth Gd negatuve anomaly. The δEu values had negatuve anomalues, sumular to the δEu values un correspondung area sedument, and δCe values showed posutuve anomalues, whuch showed that Ce had dufferent process of oxudatuon and reductuon un the organusm and sedument deposutuon. At the same tume, the enruchment relatuonshup of rare earth elements un sedument and organusm was also studued. In thus study, the content and dustrubutuon of rare earth elements un the tropucal marune fush/shellfush/shellfush were analyzed, whuch could provude basuc data for the study of the level and mugratuon and accumulatuon of rare earth elements un the envuronment of the South Chuna Sea.
ABSTRACT
A new method for accurate determination of 15 rare earth elements including Y-Lu in tea samples by inductively coupled plasma-mass spectrometry( ICP-MS) was proposed. Sample preparation was based on the modified oxygen flask combustion technique. By using quartz cloth coated with glycerol instead of filter paper as the ignition agent, a total amount of 0. 1 g sample could be completely burned in a 500-mL flask. Key factors affecting the sample preparation effect were systematically investigated, and it was found that the extraction efficiencies of over 90% for all the analytes could be realized with 5 mL of 4% HNO3+1% HF ( V/V) as the extractant for the combustion residue and the total extraction process could be finished in one minute under sonication, which resulted in a very fast sample preparation procedure that could be completed in less than 3 minutes. The relative standard deviations ( RSD) of six parallel determination values were between 2. 7% and 5. 5%, and the detection limits ranged from 0. 001 mg/kg to 0. 006 mg/kg. Three tea standard reference materials were analyzed with the method and the detection results agreed well with the standard values. The method was successfully applied to three real samples analysis.
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A microwave digestion system was preparation for the digestion of the sediment samples of 16 stations in the Southe mid_Atlantic ridge by using HNO3_H2 O2_HF as the digestion reagent. The rare earth elements ( RE ) in sediments were determined by inductively coupled plasma mass spectrometry, and distribution characteristics of rare earth elements were studied. The microwave digestion_ICP_MS method was used for the determination of rare earth elements with a good linear relationship ( r=0 . 9997-1 . 0000 ) for each element. The detection limit reached ng/L level, the relative standard deviation ( RSD, n=3 ) was less than 3% and the relative error was 6%. The total amount of rare earth elements (ΣRE) in sediment samples from 16 stations varied in the range of 37. 25-134. 77 μg/g, the ratio range of light RE/heavy RE ( LRE/HRE) was 0 . 61-1 . 70 , the average value was 1 . 27 , and the enrichment of light rare earth elements in sediments was slightly obvious. The RE distribution patterns were basically the same in each station with obvious fractionation between LRE and HRE. The RE distribution patterns were also similar in sediments from different sources with slightly difference between terrestrial and marine sediments. The δEu and δCe in the sediments had negative anomaly which showed that the rare earth elements in sediments came from the seawater. This study first analyzed the content and distribution of rare earth elements in the southern Atlantic, providing data and technical support for further study of the distribution of rare earth elements in the Atlantic.
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Objective To obtain the concentrations and daily intakes of 15 rare earth elements in foods for adult men in four areas in China.Methods With duplicate portion study,120 mixed diet samples were collected from adult men in cities of Tianjin,Chengdu,Zhenjiang and Taiyuan,which belong to 4 areas with different dietary types in China.The concentrations of cerium,dysprosium,erbium,gadolinium,lanthanum,lutetium,holmium,neodymium,praseodymium,scandium,samarium,terbium,thulium,yttrium and ytterbium in these samples were determined by Inductively Coupled Plasma Mass Spectrometry(ICP-MS) after pretreatment,and the daily intakes of them were also calculated.Results The concentrations of 15 rare earth elements and their daily intakes in foods for adult men were obtained.Conclusions The concentrations of these elements in each area are consistent with normal distribution.The total rare earth element concentration in the diet of adult men ranges from 24.68 to 109.27 μg/g.The daily intake of total rare earth elements is about 24 μg/d.Reference values of the rare earth element concentrations in the diet and daily intake of Chinese adult men were updated.
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Object To study the effect of rare-earth elements La3+ on growth of hairy roots and normal roots of Rheum palmatum L and their yield of anthraquinones. Methods The biomass and an- thraquinone yield of two hairy clones DH5c, DH7a, and normal root NOR cultures of R. palmatum were evaluated statistically after various concentration of La3+ were administrated into culture medium. Results Significant differences of biomass yield and anthraquinone yield were shown among six La3+ concentrations, in which 10 mg/L showed obvious inhibitory effect for root growth and 1. 0 mg/L was the best for anthraquinone yield. In general, aloe-emodin and rhein were predominant in five anthraquinones after treated with the rare-earth element. Conclusion The growth of hairy root cultures of R. palmatum and their anthraquinone yield are greatly promoted by addition of La3+ to the medium.
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Objective To understand the effect of cerium on the activity of SOD and CAT in Drosophila melanogaster.Methods Drosophila melanogasters were treated with cerium by adding cerium sulfate [Ce(SO4)2] into the culture medium at different concentrations(0,1,4,16,64,256 and 1 024 mg/L).The activity of SOD and CAT of the third-instar larvae were analyzed.Result Compared with the control,at 64-1 024 mg/L,the activity of SOD and CAT in the third-instar larvae significantly decreased and at 1-16 mg/L,the activity of SOD and CAT significantly increased Conclusion It suggested that cerium sulfate [Ce(SO4)2] has an oxidant toxicity to Drosophila melanogaster.
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Objective To explore the effects of yttrium nitrate on hemogram in rats Methods 48 rats were randomly divided into 4 groups,such as one control group treated with distilled water and 3 exposure groups treated with 70 mg/kg,14 mg/kg and 2 8 mg/kg yttrium nitrate via peritoneal injection twice a week for 6 weeks.After the continous 6 week exposure,the differences of hemogram between control group and exposure groups were observed Results No significant differences were observed in the counts of red blood cells,white blood cells and platelets,the contents of hemoglobulin and coagulation times between control group and each exposure group( P