Fractionation characteristics of rare earth elements (REEs) linked with secondary Fe,Mn, and Al minerals in soils     

Chunying Chang  Fangbai Li  Chengshuai Liu  Jianfeng Gao  Hui Tong  Manjia Chen 《中国地球化学学报》2016,35(4):329-339

Soil secondary minerals are important scavengers of rare earth elements (REEs) in soils and thus affect geochemical behavior and occurrence of REEs. The fractionation of REEs is a common geochemical phenomenon in soils but has received little attention, especially fractionation induced by secondary minerals. In this study, REEs (La to Lu and Y) associated with soil-abundant secondary minerals Fe-, Al-, and Mn-oxides in 196 soil samples were investigated to explore the fractionation and anomalies of REEs related to the minerals. The results show right-inclined chondrite-normalized REE patterns for La–Lu in soils subjected to total soil digestion and partial soil extraction. Light REEs (LREEs) enrichment features were negatively correlated with a Eu anomaly and positively correlated with a Ce anomaly. The fractionation between LREEs and heavy REEs (HREEs) was attributed to the high adsorption affinity of LREEs to secondary minerals and the preferred activation/leaching of HREEs. The substantial fractions of REEs in soils extracted by oxalate and Dithionite-Citrate-Bicarbonate buffer solutions were labile (10 %–30 %), which were similar to the mass fraction of Fe (10 %–20 %). Furthermore, Eu was found to be more mobile than the other REEs in the soils, whereas Ce was less mobile. These results add to our understanding of the distribution and geochemical behavior of REEs in soils, and also help to deduce the conditions of soil formation from REE fractionation.  相似文献   

柬埔寨茅草田地区地球化学异常及找矿意义     

王斌  杜明龙  李厂  邢仕  王晓东  牛志国  包振  赵青松 《世界地质》2016,35(3):752-759

对柬埔寨王国茅草田地区进行1∶5万土壤地球化学测量,以及对该区内的元素分布特征、单元素异常特征、元素相关性分析和相关元素组合异常研究,确定了找矿靶区;通过地表工程揭露,发现金矿体,验证了异常为矿致异常。  相似文献   

Vegetation dynamics in relation with climate over Nigeria from 1982 to 2011     

Tertsea Igbawua  Jiahua Zhang  Qing Chang  Fengmei Yao 《Environmental Earth Sciences》2016,75(6):518

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Assessment of soil washing for simultaneous removal of heavy metals and low-level petroleum hydrocarbons using various washing solutions     

Deok Hyun Moon  Jae-Woo Park  Agamemnon Koutsospyros  Kyung Hoon Cheong  Yoon-Young Chang  Kitae Baek  Raehyun Jo  Jeong-Hun Park 《Environmental Earth Sciences》2016,75(10):884

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Erratum to: Vegetation dynamics in relation with climate over Nigeria from 1982 to 2011     

Tertsea Igbawua  Jiahua Zhang  Qing Chang  Fengmei Yao 《Environmental Earth Sciences》2016,75(11):945

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Regional runoff variation and its response to climate change and human activities in Northwest China   总被引：1，自引：0，他引：1  

Jia Qin  Yuexia Liu  Yaping Chang  Shiwei Liu  Hongzheng Pu  Jiaxin Zhou 《Environmental Earth Sciences》2016,75(20):1366

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Spatiotemporal dynamics of the climatic impacts on greenup date in the Tibetan Plateau     

Qing Chang  Jiahua Zhang  Wenzhe Jiao  Fengmei Yao  Siyuan Wang 《Environmental Earth Sciences》2016,75(20):1343

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Dynamic changes of sediment load and water discharge in the Weihe River,China     

Jianxia Chang  Yunyun Li  Jie Wei  Yimin Wang  Aijun Guo 《Environmental Earth Sciences》2016,75(12):1042

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Thermal effects on the growth and fatty acid composition of four harmful algal bloom species: Possible implications for ichthyotoxicity     

Bonggil Hyun  Se-Jong Ju  Ah-Ra Ko  Keun-Hyung Choi  Seung Won Jung  Pung-Guk Jang  Min-Chul Jang  Chang Ho Moon  Kyoungsoon Shin 《Ocean Science Journal》2016,51(3):333-342

Little is known regarding how harmful algal bloom species respond to different temperatures in terms of fatty acid production. This study examined the effects of temperature on the growth rates, cell volumes, and fatty acid concentrations and compositions of four harmful algal bloom species (HABs), Akashiwo sanguinea, Alexandrium tamarense, Chattonella ovata, and Prorocentrum minimum. The HABs species were cultured at 15, 20, 25, and 30°C in a nutrient-enriched medium. Three of the species maintained optimal growth rates over a wide range of temperatures, but A. tamarense did not. The cell volumes of each species showed little change over the temperature range. The total fatty acid concentrations in A. sanguinea, A. tamarense and C. ovata decreased as the temperature increased, but P. minimum showed no trend in this respect. Polyunsaturated fatty acids (PUFAs), the key biochemical components that maintain cell membrane fluidity and which are associated with toxicity, decreased in both concentration and proportion of total fatty acids as temperature increased, except in A. sanguinea, in which the proportion of PUFAs to the total fatty acids increased. These reductions in PUFA concentration and proportion could reduce cell membrane fluidity and toxicity in HABs; however, enhanced growth and/or ruptured cells, which are considered more toxic than intact cells, could compensate for the reduced per-cell toxicity. This phenomenon might impact on the marine ecosystem and aquaculture industry.  相似文献   

Pharmacokinetics and acetylation of sulfamethoxazole in turbot <Emphasis Type="Italic">Scophthalmus maximus</Emphasis> after intravascular administration     

常志强  柳飞  连春盎  翟倩倩  李健 《中国海洋湖沼学报》2016,34(4):789-794

The pharmacokinetic profiles and sulfamethoxazole (SMX) acetylation process in turbot reared at 18°C were investigated. Either SMX (parent drug) or its acetylized metabolite, N₄-acetylsulfamethoxazole (AcSMX), was administered intravascularly to turbot at a dosage of 50 mg/kg BW. Serum concentrations of the parent drug and its metabolite were both measured by HPLC, and the changes in concentration over time were analyzed in two- and non-compartment models because SMX treatment produced multiple peaks. The results demonstrated that the elimination half-life of the parent drugs, SMX and AcSMX, were 159.2 and 5.9 h, respectively. The apparent volume of distribution was 0.2 and 0.8 L/kg, and the clearance was 0.038 and 0.222 L/(h·kg), for SMX and AcSMX, respectively. SMX acetylation in turbot was 2.8%, and the deacetylation of AcSMX was 0.2%. These findings may be useful in optimizing SMX dosage regimens in turbot aquaculture.  相似文献