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Sample records for platinum-group element accumulation

  1. Accumulation of platinum group elements by the marine gastropod Littorina littorea.

    PubMed

    Mulholland, Rachel; Turner, Andrew

    2011-04-01

    The accumulation and trophic transfer of the platinum group elements (PGE): Rh, Pd and Pt; have been studied in short-term (5 day) exposures conducted in aquaria containing the marine macroalga, Ulva lactuca, and/or the grazing mollusc, Littorina littorea. Metals added to sea water (to concentrations of 20 μg L⁻¹) were taken up by U. lactuca in the order Rh, Pt > Pd and by L. littorea in the order Pd ≥ Pt ≥ Rh, with greatest metal accumulation in the latter generally occurring in the visceral complex and kidney. When fed contaminated alga, accumulation of Rh and Pd by L. littorea, relative to total available metal, increased by an order of magnitude, while accumulation of Pt was not readily detected. We conclude that the diet is the most important vector for accumulation of Rh and Pd, while accumulation of Pt appears to proceed mainly from the aqueous phase. PMID:21237543

  2. Accumulation and distribution characteristics of platinum group elements in roadside dusts in Beijing, China.

    PubMed

    Gao, Bo; Yu, Yanke; Zhou, Huaidong; Lu, Jin

    2012-06-01

    The concentrations, distribution, and accumulation of platinum group elements (PGEs) were investigated in roadside dusts collected in four different foundational areas in Beijing during February to May 2010. The results showed that PGE levels in all samples were above the average upper crust values, with mean concentrations of 57.5 ng · g(-1) Pd, 28.2 ng · g(-1) Pt, and 9.8 ng · g(-1) Rh, respectively. Palladium concentration has increased rapidly in recent years. The rank of PGE levels in four different functional regions for roadside dusts was: heavy density traffic area > residential area > educational area > tourism area. Palladium, Pt, and Rh concentrations in dusts showed strong positive correlations, indicating a common traffic-related source of these metals. Meanwhile, PGEs in these samples were not correlated with other traffic-related metals except for Cr. The average PGE ratios of road dusts from Beijing were consistent with those in Germany and Western Australia, but lower than those in the United States and Mexico, indicating that various catalyst productions were used in different countries. In addition, grain-size partitioning of PGEs in dusts indicated that concentrations of PGEs differed from one particle size to another. The coarse fraction had higher PGE concentrations than the fine fraction in roadside dusts. These results showed that autocatalyst PGE contamination estimates in the environment would be significantly underestimated if only a fine-grain size fraction (<0.063 mm) is analyzed.

  3. Quantitative bioimaging of platinum group elements in tumor spheroids.

    PubMed

    Niehoff, Ann-Christin; Grünebaum, Jonas; Moosmann, Aline; Mulac, Dennis; Söbbing, Judith; Niehaus, Rebecca; Buchholz, Rebecca; Kröger, Sabrina; Wiehe, Arno; Wagner, Sylvia; Sperling, Michael; von Briesen, Hagen; Langer, Klaus; Karst, Uwe

    2016-09-28

    Limited drug penetration into tumor tissue is a significant factor to the effectiveness of cancer therapy. Tumor spheroids, a 3D cell culture model system, can be used to study drug penetration for pharmaceutical development. In this study, a method for quantitative bioimaging of platinum group elements by laser ablation (LA) coupled to inductively coupled plasma mass spectrometry (ICP-MS) is presented. Different matrix-matched standards were used to develop a quantitative LA-ICP-MS method with high spatial resolution. To investigate drug penetration, tumor spheroids were incubated with platinum complexes (Pt(II)acetylacetonate, cisplatin) and the palladium tagged photosensitizer 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (mTHPP). Distribution and accumulation of the pharmaceuticals were determined with the developed method. PMID:27619092

  4. Quantitative bioimaging of platinum group elements in tumor spheroids.

    PubMed

    Niehoff, Ann-Christin; Grünebaum, Jonas; Moosmann, Aline; Mulac, Dennis; Söbbing, Judith; Niehaus, Rebecca; Buchholz, Rebecca; Kröger, Sabrina; Wiehe, Arno; Wagner, Sylvia; Sperling, Michael; von Briesen, Hagen; Langer, Klaus; Karst, Uwe

    2016-09-28

    Limited drug penetration into tumor tissue is a significant factor to the effectiveness of cancer therapy. Tumor spheroids, a 3D cell culture model system, can be used to study drug penetration for pharmaceutical development. In this study, a method for quantitative bioimaging of platinum group elements by laser ablation (LA) coupled to inductively coupled plasma mass spectrometry (ICP-MS) is presented. Different matrix-matched standards were used to develop a quantitative LA-ICP-MS method with high spatial resolution. To investigate drug penetration, tumor spheroids were incubated with platinum complexes (Pt(II)acetylacetonate, cisplatin) and the palladium tagged photosensitizer 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (mTHPP). Distribution and accumulation of the pharmaceuticals were determined with the developed method.

  5. Roadside Accumulation of Pt, Pd, Rh and Other Trace Elements From Automobiles: Catalytic Converter Attrition and Platinum-Group Element Mobility in the Roadside Environment.

    NASA Astrophysics Data System (ADS)

    Ely, J. C.; Dahlheimer, S. R.; Neal, C. R.

    2003-12-01

    Elemental abundances of Pt, Pd and Rh have been documented across the industrialized world in roadside environments due to attrition of automotive catalytic converters (Zereini and Alt, 2000, Anthropogenic PGE Emissions, Springer, 308pp; Ely et al., 2001, EnvSci&Tech, 35:3816-3822; Whiteley and Murray, 2003, SciTotEnv, in press). In our ongoing study, the highest reported roadside Pt abundance 1.8 ppm has been found immediately adjacent to the road at a field site in South Bend, IN, USA. Furthermore, initial studies show positive correlations of Pt, Pd and Rh with some trace elements (Ni, Cu, Zn and Pb), which has been confirmed by further analysis for these and other elements (Ce, Cr). It has been demonstrated that elements such as Ce are present in catalytic converters at concentrations of 100's ppm to 3-wt.%. These elements are also being attrited with Pt, Pd and Rh and aerially transported and deposited. Our field site was established next to US-933 adjacent to the Notre Dame campus. Areas were cleared of the top 2-4 cm of soil (removing surficial Pt, Pd and Rh) at 1, 5, 10 and 50 meters from the roadside. Within 3 months the 1-meter site contained 67% of the initial Rh and Pt concentrations and 100% of the initial Pd concentration. The sites at 5, 10 and 50 meters showed similar results, in some cases exceeding the initial concentrations. After 6 months the concentrations of Pt, Pd and Rh were all within error of the initial concentrations, indicating steady state abundances had probably been reached. Grass samples from each site showed that washed vs. unwashed samples were within error of each other, and there may be a slight enrichment (approx. 1 ppb) in the grasses of Pd and Pt, but this enrichment was independent of distance from the road. The steady-state situation suggests that the PGEs are being removed from the immediate roadside environment, which requires that the metals are being oxidized and/or complexed in such a way to facilitate transport. The

  6. Platinum-group element resources in podiform chromitites from California and Oregon.

    USGS Publications Warehouse

    Page, N.J.; Singer, D.A.; Moring, B.C.; Carlson, C.A.; McDade, J.M.; Wilson, S.A.

    1986-01-01

    Assays of Pt, Pd, Rh and Ir from approx 280 podiform chromite deposits in Palaeozoic and Mesozoic ophiolites are statistically analysed to estimate their possible by-product value from mining the chromite. The platinum-group elements occur in discrete platinum-group minerals, and in solid solution in Cu-Ni-Fe sulphides. Low grades and small amounts of total platinum-group elements in podiform chromite deposits imply a small resource. -G.J.N.

  7. Platinum-group elements: so many excellent properties

    USGS Publications Warehouse

    Zientek, Michael L.; Loferski, Patricia J.

    2014-01-01

    The platinum-group elements (PGE) include platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals have similar physical and chemical properties and occur together in nature. The properties of PGE, such as high melting points, corrosion resistance, and catalytic qualities, make them indispensable to many industrial applications. PGE are strategic and critical materials for many nations because they are essential for important industrial applications but are mined in a limited number of places and have no adequate substitutes. Exploration and mining companies have found approximately 104,000 metric tons of PGE (with minor gold) in mineral deposits around the world that could be developed. For PGE, almost all known production and resources are associated with three geologic features: the Bushveld Complex, a layered mafic-to-ultramafic intrusion in South Africa; the Great Dyke, a layered mafic-to-ultramafic intrusion in Zimbabwe; and sill-like intrusions associated with flood basalts in the Noril’sk-Talnakh area, Russia. To help predict where PGE supplies might be located, USGS scientists study how and where PGE resources are concentrated in the Earth's crust and use that knowledge to assess the likelihood that undiscovered PGE deposits may exist. Techniques used for assessing mineral resources were developed by the USGS to support the stewardship of Federal lands and evaluate mineral resource availability in a global context. The USGS also compiles statistics and information on the worldwide supply, demand, and flow of PGE. These data are all used to inform U.S. national policymakers.

  8. Bioaccessibility of platinum group elements in automotive catalytic converter particulates.

    PubMed

    Turner, Andrew; Price, Simon

    2008-12-15

    The bioaccessibilities of the platinum group elements (PGE): Rh, Pd, and Pt; and the catalyzator poison, Pb, have been determined in particles derived from milled automotive catalytic converters using a physiologically based extraction test (PBET) that simulates, sequentially, the chemical conditions encountered in the human stomach and intestine. PGE accessibility, relative to total metal concentration, was generally less than a few percent, but increased in the stomach with decreasing pH (from 4 to 1) and/or increasing chloride concentration, and with decreasing particle concentration. In most cases, bioaccessibility increased from the acidic stomach to the neutral, carbonate-rich intestine. Bioaccessibility of Pb displayed similar pH and particle concentration dependencies to PGE in the stomach, but this metal exhibited significantly greater mobilization (up to 80%) overall and a reduction in accessibility from the stomach to intestine. Reaction kinetics of PGE dissolution in the stomach at pH 2.5 were modeled using a combined surface reaction-diffusion controlled mechanism with rate constants of 0.068, 0.031, and 0.015 (microg L(-1))(-1) h(-1) for Rh, Pd, and Pt, respectively. For Pb, however, mobilization proceeded via a different mechanism whose time-dependence was fitted with an empirical, logarithmic equation. Overall, PGE bioaccessibility appeared to be controlled by dissolution rates of metallic nanoparticles in the stomach, and solubility and kinetic constraints on inorganic species (chlorides, hydroxychlorides, and carbanatochlorides) and undefined organic complexes formed in the simulated gastrointestinal tract. Further studies are required to elucidate any effects engendered by the long-term oral exposure of small quantities of these species. PMID:19174929

  9. Platinum group elements in mantle melts and mantle samples

    NASA Astrophysics Data System (ADS)

    Barnes, Stephen J.; Mungall, James E.; Maier, Wolfgang D.

    2015-09-01

    A large data compilation has been assembled of platinum group element (PGE) analyses in mantle melts and mantle rocks, the latter including an assortment of xenoliths and obducted mantle massifs. The degree of correlation has been investigated among the PGEs and with other major element variables such as Al2O3, TiO2 and Mg number, and the results are considered in the context of the current paradigm for the behaviour of highly siderophile elements in the silicate Earth. Primitive mantle melts have a wide range of PGE contents. Komatiites have the highest abundances of all the PGEs, show the strongest correlations between Pt and Rh, Pt and Pd and between the iridium-group PGEs Ir, Ru and Os (IPGEs). Most basalts of all affinities have lower levels of Pt and Pd and much lower levels of Ir, Ru and Os than komatiites. Within the basalt grouping Rh has stronger affinities with the IPGEs. Picrites and Archaean basalts are intermediate between these two groups. MORBs and a small proportion of continental LIP basalts show strong depletions in all PGEs attributable to retention of sulfide in their mantle source rocks, or sulfide liquid fractionation on ascent. The degree of PGE depletion in other basalts is probably attributable to equilibration with sulfide, but is less than would be expected under conventional models of sulfide extraction, and is instead attributed to mixing of magmas generated at variable depths incorporating both sulfide-saturated and undersaturated components. Basalts with Pt and Pd contents higher than typical komatiites are rare, a notable example being B1-type parent magmas to the Bushveld Complex, which have komatiite-like relative PGE abundances and Pt, Pd and Rh abundances up to a factor of two higher than komatiites for comparable Ti contents. The mantle composition array as a whole is characterized by variable degrees of depletion of Pt, Pd and Rh in Al-poor, melt-depleted harzburgite/dunite lithologies; lack of depletion in these elements in

  10. Concentrations of platinum group elements in 122 U.S. coal samples

    USGS Publications Warehouse

    Oman, C.L.; Finkelman, R.B.; Tewalt, S.J.

    1997-01-01

    Analysis of more than 13,000 coal samples by semi-quantitative optical emission spectroscopy (OES) indicates that concentrations of the platinum group elements (iridium, palladium, platinum, osmium, rhodium, and ruthenium) are less than 1 ppm in the ash, the limit of detection for this method of analysis. In order to accurately determine the concentration of the platinum group elements (PGE) in coal, additional data were obtained by inductively coupled plasma mass spectroscopy, an analytical method having part-per-billion (ppb) detection limits for these elements. These data indicate that the PGE in coal occur in concentrations on the order of 1 ppb or less.

  11. Towards the analysis of platinum group elements at low levels in insulating materials

    NASA Astrophysics Data System (ADS)

    Krestow, J. S. A.; Kieser, W. E.; Litherland, A. E.; Rucklidge, J. C.; Wilson, G. C.; Zhao, X.-L.

    2007-06-01

    The operating parameters for a high current caesium sputter source have been modified so that stable beams of anions can be obtained from natural non-conducting samples. This technique has been applied to the analysis of gold and platinum group elements in silicate matrices, particularly olivines. The handling of interferences resulting from the large number of molecular ions produced in such a target, and the effect of differences in the matrices of reference materials are discussed.

  12. Leaves of Phragmites australis as potential atmospheric biomonitors of Platinum Group Elements.

    PubMed

    Bonanno, Giuseppe; Pavone, Pietro

    2015-04-01

    The increasing emissions of Platinum Group Elements (PGEs), namely Pt, Pd and Rh, may pose a significant risk to ecosystem processes and human health. A periodic assessment of PGEs distribution in the environment is thus of the utmost importance for the implementation of timely measures of mitigation. Although several studies have quantified PGEs in different life forms such as mammals, birds, fish, crustaceans, algae, mosses and even human beings, data about vascular plants need further surveys. This study aimed to test the suitability of the grass Phragmites australis (common reed) as a biomonitor of PGEs atmospheric pollution. The results showed that Pd and Pt concentrations in leaves are significantly higher in urban areas. In particular, Pd showed the highest range of values in line with current studies that consider palladium as the main element of traffic-related pollution. Overall, the leaves of Phragmites australis reflected the different gradient of PGEs emissions, and may thus be considered as potential biomonitors of atmospheric pollution.

  13. Platinum-group element geochemistry of zoned ultramafic intrusive suites, Klamath Mountains, California and Oregon.

    USGS Publications Warehouse

    Gray, F.; Page, N.J.; Carlson, C.A.; Wilson, S.A.; Carlson, R.R.

    1986-01-01

    Analyses for platinum-group elements of the varied rock suites of three Alaskan-type ultramafic to mafic multi-intrusive bodies are reported. Ir and Ru are less than analytical sensitivities of 100 and 20 ppb; Rh is less than or near 1 ppb. Average Pd assays vary among the rocks within intrusive complexes and between the three complexes (6.3, 13.7, 36.4 ppb); average Pt assays vary little among the same samples (27.9, 60.9, 34.0 ppb). Statistically adjusted Pt/(Pt + Pd) ratios increase in each suite from gabbro through clinopyroxenite to olivine-rich rocks, possibly owing to Pd fractionation.-G.J.N.

  14. Characterization of the Sukinda and Nausahi ultramafic complexes, Orissa, India by platinum-group element geochemistry

    USGS Publications Warehouse

    Page, N.J.; Banerji, P.K.; Haffty, J.

    1985-01-01

    Samples of 20 chromitite, 14 ultramafic and mafic rock, and 9 laterite and soil samples from the Precambrian Sukinda and Nausahi ultramafic complexes, Orissa, India were analyzed for platinum-group elements (PGE). The maximum concentrations are: palladium, 13 parts per billion (ppb); platinum, 120 ppb; rhodium, 21 ppb; iridium, 210 ppb; and ruthenium, 630 ppb. Comparison of chondrite-normalized ratios of PGE for the chromitite samples of lower Proterozoic to Archean age with similar data from Paleozoic and Mesozoic ophiolite complexes strongly implies that these complexes represent Precambrian analogs of ophiolite complexes. This finding is consistent with the geology and petrology of the Indian complexes and suggests that plate-tectonic and ocean basin developement models probably apply to some parts of Precambrian shield areas. ?? 1985.

  15. Rhenium-osmium isotope systematics and platinum group element concentrations: Loess and the upper continental crust

    NASA Astrophysics Data System (ADS)

    Peucker-Ehrenbrink, Bernhard; Jahn, Bor-Ming

    2001-10-01

    We investigate the use of loess as a proxy for the concentration and isotopic composition of highly siderophile elements, specifically Os, in the upper continental crust. The 187Os/188Os, platinum group element, and Re concentrations of 16 loess samples from China, Europe, and South America, previously analyzed for major, trace element, and Sr and Nd isotope composition, reveal subtle differences between loess provinces. Despite those differences, the 187Os/188Os of 1.05 ± 0.23 is surprisingly homogenous. Average 187Os/188Os as well as average Os (31 pg/g) and Ir (22 pg/g) concentrations are similar to the lower limit of previous estimates for average upper continental crust, whereas Ru, Pt, and Pd concentrations are intermediate between previous estimates. We argue that hydrogenous enrichment of Os in riverine sediments led Esser and Turekian [1993] to overestimate the Os concentration of upper continental crust (50 pg/g). On the basis of this argument and correlations with major and trace elements we propose that average platinum group element concentrations of loess (i.e., 31 pg Os/g, 22 pg Ir/g, 210 pg Ru/g, 510 pg Pt/g, 520 pg Pd/g) are a proxy for the upper continental crust. We further suggest that the nonchondritic average Os/Ir of 1.4 reflects the combined effects of radiogenic ingrowth of Os from Re decay over the mean lifetime of the upper continental crust and preferential return of Os to the crust during subduction. Rhenium concentrations scatter significantly, with highest values in loess derived from organic-rich sedimentary rocks. Low median Re concentrations most likely reflect depletion of loess in organic matter, an important sink for Re in the upper continental crust. An average 187Re/188Os of 34.5 was calculated on the basis of the measured 187Os/188Os and Nd model ages. This value corresponds to a Re concentration of 198 pg/g. Correcting measured 187Os/188Os = 1.05 and inferred 186Os/188Os = 0.119871 (from 190Pt/188Os = 0.0176) for the older

  16. Geophysical Imaging of the Stillwater and Bushveld Complexes and Relation to Platinum-group Element Exploration

    NASA Astrophysics Data System (ADS)

    Finn, C.; Bedrosian, P.; Zientek, M. L.; Cole, J.; Webb, S. J.; Bloss, B. R.

    2015-12-01

    Exploring for platinum-group elements (PGEs) relies on understanding the geophysical signature of the entire magmatic system in which they form, from bottom to top. New potential field and electromagnetic data and methods effectively map internal structures of layered intrusions that host PGE-bearing magmatic ore deposits, the volume of the intrusion and its extent under cover, and locations of sulfide mineralization. High resolution aeromagnetic data can image fine scale linear anomalies related to layering in the Stillwater and Bushveld Complexes. At Stillwater, the aeromagnetic anomalies relate to boundaries between major stratigraphic units and olivine-bearing rock layers altered to a mixture of serpentine and magnetite. The PGE-enriched sulfide mineralization hosted by olivine-bearing rocks in the Stillwater Complex produces a distinct linear magnetic high. In the Upper Zone of the Bushveld Complex, primary magnetite layers generate linear magnetic highs. Electromagnetic (EM) data over the Stillwater Complex highlight contact-type mineralization which contain low resistivity sulfide minerals. Stochastic inversions reveal a low resistivity zone along the southern edge of the Stillwater Complex corresponding to mineralization in banded iron formation or contact-type sulfide mineralization in the Basal zone. Gravity highs characterize the exposed and interpreted buried extent of the Stillwater and Bushveld complexes. A 3D inversion of gravity data of the Sillwater Complex indicates that the complex extends 30 km north and 40 km east of its outcrop beneath Phanerozoic cover. Geophysical models image the 3D geometry of the Bushveld Complex north of the Thabazimbi-Murchison Lineament (TML), critical for understanding the origin of the world's largest layered mafic intrusion and associated platinum- group element deposits, as a ~4 km thick, 160 km x ~125 km body underlying ~1-2 km of cover. Locally thick regions in the TML portion of the model may represent feeders

  17. Partitioning of Si and platinum group elements between liquid and solid Fe-Si alloys

    NASA Astrophysics Data System (ADS)

    Morard, G.; Siebert, J.; Badro, J.

    2014-05-01

    Crystallization of the Earth's inner core fractionates major and minor elements between the solid and liquid metal, leaving physical and geochemical imprints on the Earth's core. For example, the density jump observed at the Inner Core Boundary (ICB) is related to the preferential partitioning of lighter elements in the liquid outer core. The fractionation of Os, Re and Pt between liquid and solid during inner core crystallization has been invoked as a process that explains the observed Os isotopic signature of mantle plume-derived lavas (Brandon et al., 1998; Brandon and Walker, 2005) in terms of core-mantle interaction. In this article we measured partitioning of Si, Os, Re and Pt between liquid and solid metal. Isobaric (2 GPa) experiments were conducted in a piston-cylinder press at temperatures between 1250 °C and 1600 °C in which an imposed thermal gradient through the sample provided solid-liquid coexistence in the Fe-Si system. We determined the narrow melting loop in the Fe-Si system using Si partitioning values and showed that order-disorder transition in the Fe-Si solid phases can have a large effect on Si partitioning. We also found constant partition coefficients (DOs, DPt, DRe) between liquid and solid metal, for Si concentrations ranging from 2 to 12 wt%. The compact structure of Fe-Si liquid alloys is compatible with incorporation of Si and platinum group elements (PGEs) elements precluding solid-liquid fractionation. Such phase diagram properties are relevant for other light elements such as S and C at high pressure and is not consistent with inter-elemental fractionation of PGEs during metal crystallization at Earth's inner core conditions. We therefore propose that the peculiar Os isotopic signature observed in plume-derived lavas is more likely explained by mantle source heterogeneity (Meibom et al., 2002; Baker and Krogh Jensen, 2004; Luguet et al., 2008).

  18. Levels of platinum group elements and rare-earth elements in wild mushroom species growing in Poland.

    PubMed

    Mleczek, Mirosław; Niedzielski, Przemysław; Kalač, Pavel; Siwulski, Marek; Rzymski, Piotr; Gąsecka, Monika

    2016-01-01

    Due to limited data-describing abilities of mushrooms to accumulate platinum group elements (PGEs) and rare-earth elements (REEs), the aim of this study was to determine, by inductively coupled plasma optical emission spectrometry followed by microwave-assisted sample digestion by nitric acid, the content of these elements in 20 mushroom species (10 above ground and 10 growing on wood), mostly edible, collected near a busy trunk road. The highest content of PGEs in above-ground mushroom species was observed in Lepista gilva and Suillus bovinus fruit bodies (0.38 ± 0.05 and 0.37 ± 0.03 mg kg(-1) DW, respectively), while in mushrooms growing on wood, the highest content was observed in Pleurotus ostreatus (0.35 ± 0.04 mg kg(-1) DW). The mean content of PGEs for both these groups was 0.23 ± 0.08 and 0.26 ± 0.07 mg kg(-1) DW, respectively. The highest content of REEs in Suillus luteus and Tricholoma equestra was 5.03 ± 0.50 and 2.18 ± 0.56 mg kg(-1) DW, respectively, but within mushrooms growing on wood in Ganoderma applanatum fruiting bodies it was 4.19 ± 0.78 mg kg(-1) DW. Mean contents of REEs were 1.39 ± 1.21 and 1.61 ± 0.97 mg kg(-1) DW in above-ground species and species growing on wood, respectively. Generally, the group of mushroom species growing on wood was capable of slightly higher accumulation of both REEs and PGEs. No limits have been established for both the groups until now. PMID:26515437

  19. Levels of platinum group elements and rare-earth elements in wild mushroom species growing in Poland.

    PubMed

    Mleczek, Mirosław; Niedzielski, Przemysław; Kalač, Pavel; Siwulski, Marek; Rzymski, Piotr; Gąsecka, Monika

    2016-01-01

    Due to limited data-describing abilities of mushrooms to accumulate platinum group elements (PGEs) and rare-earth elements (REEs), the aim of this study was to determine, by inductively coupled plasma optical emission spectrometry followed by microwave-assisted sample digestion by nitric acid, the content of these elements in 20 mushroom species (10 above ground and 10 growing on wood), mostly edible, collected near a busy trunk road. The highest content of PGEs in above-ground mushroom species was observed in Lepista gilva and Suillus bovinus fruit bodies (0.38 ± 0.05 and 0.37 ± 0.03 mg kg(-1) DW, respectively), while in mushrooms growing on wood, the highest content was observed in Pleurotus ostreatus (0.35 ± 0.04 mg kg(-1) DW). The mean content of PGEs for both these groups was 0.23 ± 0.08 and 0.26 ± 0.07 mg kg(-1) DW, respectively. The highest content of REEs in Suillus luteus and Tricholoma equestra was 5.03 ± 0.50 and 2.18 ± 0.56 mg kg(-1) DW, respectively, but within mushrooms growing on wood in Ganoderma applanatum fruiting bodies it was 4.19 ± 0.78 mg kg(-1) DW. Mean contents of REEs were 1.39 ± 1.21 and 1.61 ± 0.97 mg kg(-1) DW in above-ground species and species growing on wood, respectively. Generally, the group of mushroom species growing on wood was capable of slightly higher accumulation of both REEs and PGEs. No limits have been established for both the groups until now.

  20. New SSMS Techniques for the Determination of Rhodium and Other Platinum- Group Elements in Carbonaceous Chondrites

    NASA Astrophysics Data System (ADS)

    Jochum, K. P.; Seufert, H. M.

    1995-09-01

    We have developed new spark source mass spectrometric (SSMS) techniques for simultaneous analysis of platinum-group elements (PGE) together with other trace elements in stony meteorites. We have measured elemental abundances of Rh, Ru, Os, Ir, Pt, Au in carbonaceous chondrites of different types including the two CI chondrites Orgueil and Ivuna. These data are relevant for the determination of solar-system abundances. Whereas the solar-system abundances of most PGE are well known, this is not the case for Rh, and no literature data exist for carbonaceous chondrites, mainly because of analytical difficulties. The SSMS techniques include new calibration procedures and the use of a recently developed multi-ion counting (MIC) system [1]. The mono-isotopic element Rh and the other PGE were determined by using internal standard elements (e.g., Nd, U) that were measured by isotope dilution in the same sample electrode material. The data were calibrated with certified standard solutions of PGE which were doped on trace-element poor rock samples. Ion abundances were measured using both the conventional photoplate detection and the ion-counting techniques. The new MIC technique that uses up to 20 small channeltrons for ion counting measurements has the advantage of improved precision, detection limits and analysis time compared to photoplate detection. Tab. 1 shows the Rh analyses for the meteorites Orgueil, Ivuna, Murchison, Allende and Karoonda obtained by conventional photoplate detection. These are the first Rh results for carbonaceous chondrites. The data for the two CI chondrites Orgueil and Ivuna are identical and agree within 4 % with the CI estimate of Anders and Grevesse [2] which was derived indirectly from analyses for H-chondrites. The PGE Os, Ir, Pt, Au and W, Re, Th, U concentrations were determined by both detection systems. Data obtained with the MIC system are more precise (about 4% for concentrations in the ppb range) compared to the photoplate detection

  1. [Pollution characteristics of platinum group elements in road rust in Xiamen].

    PubMed

    Hong, Zhen-yu; Hong, You-wei; Yin, Li-qian; Chen, Jin-sheng; Chen, Yan-ting; Xu, Ling-ling

    2015-01-01

    With the potential risks for the environment and human health, the concentration and distribution characteristics of platinum group element(PGEs) in road dust in Xiamen city were investigated. Road dust samples were collected from the traffic trunk road, tunnel, tourism area, and industrial area of Xiamen on October 2012. The samples were digested with aqua regia in a microwave assisted digestion system under high pressure condition, separated and purified with cation exchange resin( Dowex AG50W-X8), and the resulting solutions were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the average concentrations(range) of Pd, Pt and Rh in road dust were 246.82 (58.68-765.52) ng x g(-1), 95.45 (42.14-371.36) ng x g(-1) and 51.76 (21.04-119.72) ng x g(-1), respectively, which were two orders of magnitude higher than the background values. Compared with other cities worldwide, the concentrations of Pd, Pt and Rh in road dust in Xiamen were at higher levels. Theconcentrations of PGEs for different functional areas were listed in the following order: tunnel > urban district > industrial area > tourism area, which indicated that their spatial distributions were mainly affected by the traffic intensity. Correlation analysis results showed that concentration of Pd in the urban traffic artery was significantly correlated with Rh, while Pt was not so correlated with Pd and Rh, suggesting that other sources contributed to PGEs in road dust in addition to the vehicle emission. Although motor vehicle traveling was banned in tourist area, the concentration of PGEs was still at a high level. Some of them might originate from the road dust in surrounding area by atmosphere diffusion. PMID:25898678

  2. [Pollution characteristics of platinum group elements in road rust in Xiamen].

    PubMed

    Hong, Zhen-yu; Hong, You-wei; Yin, Li-qian; Chen, Jin-sheng; Chen, Yan-ting; Xu, Ling-ling

    2015-01-01

    With the potential risks for the environment and human health, the concentration and distribution characteristics of platinum group element(PGEs) in road dust in Xiamen city were investigated. Road dust samples were collected from the traffic trunk road, tunnel, tourism area, and industrial area of Xiamen on October 2012. The samples were digested with aqua regia in a microwave assisted digestion system under high pressure condition, separated and purified with cation exchange resin( Dowex AG50W-X8), and the resulting solutions were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the average concentrations(range) of Pd, Pt and Rh in road dust were 246.82 (58.68-765.52) ng x g(-1), 95.45 (42.14-371.36) ng x g(-1) and 51.76 (21.04-119.72) ng x g(-1), respectively, which were two orders of magnitude higher than the background values. Compared with other cities worldwide, the concentrations of Pd, Pt and Rh in road dust in Xiamen were at higher levels. Theconcentrations of PGEs for different functional areas were listed in the following order: tunnel > urban district > industrial area > tourism area, which indicated that their spatial distributions were mainly affected by the traffic intensity. Correlation analysis results showed that concentration of Pd in the urban traffic artery was significantly correlated with Rh, while Pt was not so correlated with Pd and Rh, suggesting that other sources contributed to PGEs in road dust in addition to the vehicle emission. Although motor vehicle traveling was banned in tourist area, the concentration of PGEs was still at a high level. Some of them might originate from the road dust in surrounding area by atmosphere diffusion.

  3. [Migration and transformation of anthropogenic platinum group elements in environment: a review].

    PubMed

    Li, Pei-Miao; Gao, Xue-Lu

    2012-12-01

    Anthropogenic platinum group elements (PGEs) are widely applied in vehicle exhaust catalytic converters (VECs), industrial catalysts, and pharmaceutics, making the PGEs, especially Pt, Pd, and Rh, become the newly environmental pollutants in some fields. Given the positive correlations between the Pt/Pd and Pt/Rh ratios in various environmental samples and the active components of VECs, the VECs containing PGEs as catalysts are regarded as the primary source of PGEs pollution. Sufficient reports indicated that in the past three decades, there was a significant increase of PGEs concentrations in diverse environmental matrices like airborne particulate matters, aquatic ecosystem components (e.g., river water, rain water, groundwater, seawater, and sediments), soils, road dusts, and organisms. It was generally assumed that anthropogenic PGEs behave in inert manner, and the health risks associated with the environmental exposures to PGEs are minimal. However, the recent studies on PGEs toxicity and environmental bioavailability indicated that once entering environment, anthropogenic PGEs might easily be mobilized and transformed into more toxic forms under the actions of various biogeochemical processes, and thereby, enhanced their bioavailability and posed potential health risks to human beings through food chain. This paper summarized the research results about the sources, distribution, and biogeochemical behaviors of PGEs in various environmental media, and it was considered that to establish the standards of PGEs for human health risks, to develop standard substances of PGEs for environmental measurements, to study the PGEs in the sediments of marginal seas, and to assess the toxicity of PGEs to marine mollusks, the present contamination status of PGEs in foods, and the risks of PGEs to human health would be the hot research topics in the future.

  4. Distribution of platinum group elements and other traffic related elements among different plants along some highways in Germany.

    PubMed

    Djingova, Rumiana; Kovacheva, Petya; Wagner, Gerhard; Markert, Bernd

    2003-06-01

    Using ICP-MS and ICP-AES platinum group elements (Pt, Pd, Rh, Ru and Ir) and Ce, La, Nd, Pb and Zr have been determined in street dust, Taraxacum officinale (dandelion), Plantago lanceolata (plantain), Lolium multiflorum (annual ryegrass), Rhytidiadelphus squarrosus (moss) and Vascellum pratense (mushrooms) collected along highways and streets in Germany during 1999. Among the plants Taraxacum officinale (dandelion) reflects most adequately the pollution with the investigated elements matching the results from street dust. A strong positive correlation between all elements determined in the plants is established. Transfer factor for Pt between soil and plants has been determined in an agricultural experiment ranging between 0.004 and 0.008 for two types of soils. PMID:12738216

  5. Separating Continental Mineral Dust from Cosmic Dust using Platinum Group Element Concentrations and Osmium Isotopes in Ancient Polar Ice

    NASA Astrophysics Data System (ADS)

    Seo, J. H.; Jackson, B.; Osterberg, E. C.; Sharma, M.

    2015-12-01

    The platinum group element (PGEs: Pt, Pd, Rh, Ir, Os, and Ru) accumulation in ancient polar archives have been argued to trace cosmic dust and "smoke" from larger meteors but the PGE concentration data lack specificity. For example, the extent to which the terrestrial volcanism/dust has contributed to the PGE inventory of polar ice cannot be readily evaluated. Since the Os isotope compositions (187Os/188Os ratio) of the terrestrial and extraterrestrial sources are distinctly different from each other, the PGE concentrations when combined with Os isotope composition have the potential to untangle contributions from these sources. Platinum group element concentration determinations in polar ice cores are highly challenging due to their extremely low concentrations (down to 10-15 g/g or fg/g). Here, a new procedure is presented that allows PGEs and Os isotope compositions to be determined from a ~50 g sample of polar ice. Decontaminated ice-melt is spiked with 101Ru, 106Pd, 190Os, 191Ir, and 198Pt and frozen at -20 °C in quartz-glass ampoules. A mixture of purified HNO3 and H2O2 is then added and the sample is heated to 300 °C at 128bar using a High Pressure Asher. This allows all spikes to be equilibrated with the sample PGEs and all Os species are oxidized to OsO4. The resulting OsO4 is extracted using distillation, purified, and measured using negative thermal ionization mass spectrometry. PGEs are then separated and purified using two stage column chromatography and their concentrations determined by isotope dilution using a triple quadruople inductively coupled plasma mass spectrometer coupled to an Apex de-solvation nebulizer. The developed method was applied to modern Greenland firn and snow. The PGE concentrations of the firn are 4.0 fg/g for Ir, 20 fg/g for Ru, 590 fg/g for Pt, 38 fg/g for Pd, and 1.3 fg/g for Os, while those of the snow are 3.0 fg/g for Ir, 53 fg/g for Ru, 360 fg/g for Pt, 32 fg/g for Pd, and 0.4 fg/g for Os, respectively. A comparison

  6. High salinity volatile phases in magmatic Ni-Cu-platinum group element deposits

    NASA Astrophysics Data System (ADS)

    Hanley, J. J.; Mungall, J. E.

    2004-12-01

    The role of "deuteric" fluids (exsolved magmatic volatile phases) in the development of Ni-Cu-PGE (platinum group element) deposits in mafic-ultramafic igneous systems is poorly understood. Although considerable field evidence demonstrates unambiguously that fluids modified most large primary Ni-Cu-PGE concentrations, models which hypothesize that fluids alone were largely responsible for the economic concentration of the base and precious metals are not widely accepted. Determination of the trace element composition of magmatic volatile phases in such ore-forming systems can offer considerable insight into the origin of potentially mineralizing fluids in such igneous environments. Laser ablation ICP-MS microanalysis allows researchers to confirm the original metal budget of magmatic volatile phases and quantify the behavior of trace ore metals in the fluid phase in the absence of well-constrained theoretical or experimental predictions of ore metal solubility. In this study, we present new evidence from major deposits (Sudbury, Ontario, Canada; Stillwater Complex, Montana, U.S.A.) that compositionally distinct magmatic brines and halide melt phases were exsolved from crystallizing residual silicate melt and trapped within high-T fluid conduits now comprised of evolved rock compositions (albite-quartz graphic granite, orthoclase-quartz granophyre). Petrographic evidence demonstrates that brines and halide melts coexisted with immiscible carbonic phases at the time of entrapment (light aliphatic hydrocarbons, CO2). Brine and halide melt inclusions are rich in Na, Fe, Mn, K, Pb, Zn, Ba, Sr, Al and Cl, and homogenize by either halite dissolution at high T ( ˜450-700° C) or by melting of the salt phase (700-800° C). LA-ICPMS analyses of single inclusions demonstrate that high salinity volatile phases contained abundant base metals (Cu, Fe, Sn, Bi) and precious metals (Pt, Pd, Au, Ag) at the time of entrapment. Notably, precious metal concentrations in the inclusions

  7. Issues of platinum group element concentration analysis: Do we have solutions?

    NASA Astrophysics Data System (ADS)

    Meisel, T.; Becker, H.; Walker, R. J.

    2004-05-01

    When addressing digestion techniques, sample inhomogeneity, reagent blanks and spike sample equilibration are issues of major concern. The issue of complete digestions is often overseen or neglected. Reasons are a) the lack of reference materials certified for PGE concentrations to validate methods, b) too few collaborative trials concerning PGE analysis (proficiency tests), c) assumptions made on complete digestions, d) the lack of alternative digestions method to validate analytical methods and e) large measurement uncertainties that do not allow for detection of bias. Acid digestions in Carius tubes (CT) where originally introduced (ca 1860) to digest organic material for major element analyses. In the 1940 CT were described as effective digestion method of platinum group elements applying temperatures of up to 300° C. In the early 1990s CT heated to about 230° C for silicate rock digestions for the Re-Os isotopic analysis. With the increasing interest in determining PGE with isotope dilution ICP-MS, CT were later on used for sample digestions, partially replacing the classical fire assay technique with NiS. The temperature of 230° C was thought to be sufficient for complete digestion and was not raised due to safety concerns. Recent studies show that CT do not release all the PGE contained in peridotites. It can be demonstrated that higher temperatures (greater 300° C) need to be attained to achieve complete digestions. The use of a high pressure asher (HPA-S) device makes complete PGE digestions of less than 4 g of silicates or chromites at temperatures up to 320° C in a extremely safe environment possible. The recent reintroduction of the original constructions for CT digestions of the 1940s now allow digestions even at 345° C and more. The home made device, which was build after the plan from NIST, is probably as efficient as HPA-S digestions. One advantage of the classical NiS fire assay is the possibility to process large sample amounts which should

  8. Mobility of rhenium, platinum group elements and organic carbon during black shale weathering

    NASA Astrophysics Data System (ADS)

    Jaffe, Lillie A.; Peucker-Ehrenbrink, Bernhard; Petsch, Steven T.

    2002-05-01

    This study investigates the effects of black shale weathering on the Re-Os isotope system, platinum group element concentrations and the degradation of organic matter. Samples from a weathering profile in Late Devonian (˜365 Myr) Ohio Shale show a pronounced decrease (˜77%) in organic carbon (C org) near the present soil surface, relative to the interior portion of the outcrop. A similar trend is observed for total N (˜67% loss). Conversely, organic phosphorus (P org) concentrations increase by ˜59% near the soil surface. The decrease in C org is accompanied by a pronounced decrease in Re (˜99%) and, to a lesser extent, Os (˜39%). Palladium and Pt do not appear to be significantly mobile. The effects of Re and Os mobility on the Re-Os isotope system are significant: none of the samples plots on a 365 Myr isochron. Rather, the samples define a trend with a slope corresponding to an age of ˜18 Myr with an initial 187Os/ 188Os of ˜6.1. This indicates recent disturbance of the Re-Os system. Isotope mass balance calculations imply that the labile fraction of Os is significantly more radiogenic ( 187Os/ 188Os of ˜7.8) than the average of the unweathered samples ( 187Os/ 188Os of ˜6.4). Based on data from this study, the molar ratio of labile Re to C org in Ohio Shale is estimated at 7×10 -8. We estimate the present-day riverine, black shale-derived Re flux to seawater using literature data on Re burial in anoxic marine sediments, and assuming steady-state between Re release during black shale weathering and Re burial in anoxic marine sediments. Then, the labile Re/C org observed in this study implies that ˜0.5 Tmol of C org is released annually from weathering of black shales, a trace lithology in the continental crust. This flux corresponds to ˜12% of the estimated annual CO 2 flux from oxidative weathering of sedimentary rocks. The labile molar Re/Os of ˜270 indicates that black shale weathering releases ˜130 mol Os per year, which accounts for ˜7% of

  9. Sulfide saturation history of the Stillwater Complex, Montana: chemostratigraphic variation in platinum group elements

    NASA Astrophysics Data System (ADS)

    Keays, Reid R.; Lightfoot, Peter C.; Hamlyn, Paul R.

    2012-01-01

    A platinum group element (PGE) investigation of a 5.3 km-thick stratigraphic section of the Stillwater Complex, Montana was undertaken to refine and test a geochemical technique to explore for platiniferous horizons in layered mafic/ultramafic complexes. PGE, Au, major, and trace elements were determined in 92 samples from outcrops along traverses in the Chrome Mountain and Contact Mountain areas in the western part of the Stillwater Complex where the J-M reef occurs ˜1,460 m above the floor of the intrusion. A further 29 samples from a drill hole cored in the immediate vicinity of the J-M reef were analyzed to detail compositional variations directly above and below the J-M reef. Below the J-M reef, background concentrations of Pt (10 ppb) and Pd (7 ppb) are features of peridotites with intermediate S concentrations (mostly 100-200 ppm) and rocks from the Bronzitite, Norite I, and Gabbronorite I zones (mostly <100 ppm S). A sustained increase in S abundance commences at the J-M reef and continues to increase and peaks in the center of the 600 m-thick middle banded series. Over this same interval, Pt, Pd, and Au are initially elevated and then decrease in the order Pd > Pt > Au. Within the middle and upper banded series, S abundances fluctuate considerably, but exhibit an overall upward increase. The behavior of these elements records periodic sulfide saturation during deposition of the Peridotite zone, followed by crystallization under sulfide-undersaturated conditions until saturation is achieved at the base of the J-M reef. Following formation of the reef, sulfide-saturated conditions persisted throughout the deposition of most of the remaining Lower Layered Series. This resulted in a pronounced impoverishment in PGE abundance in the remaining magma, a condition that continued throughout deposition of the remainder of a succession, which is characterized by very low Pt (1.5 ppb) and Pd (0.7 ppb) abundances. Because only unmineralized rock was selected for study

  10. Platinum group elements in a 3.5 Ga nickel-iron occurrence - Possible evidence of a deep mantle origin

    NASA Technical Reports Server (NTRS)

    Tredoux, Marian; Hart, Rodger J.; Lindsay, Nicholas M.; De Wit, Maarten J.; Armstrong, Richard A.

    1989-01-01

    This paper reports the results of new field observations and the geochemical analyses for the area of the Bon Accord (BA) (the Kaapvaal craton, South Africa) Ni-Fe deposit, with particular consideration given to the trace element, platinum-group element, and isotopic (Pb, Nd, and Os) compositions. On the basis of these data, an interpretation of BA is suggested, according to which the BA deposit is a siderophile-rich heterogeneity remaining in the deep mantle after a process of incomplete core formation. The implications of such a model for the study of core-mantle segregation and the geochemistry of the lowermost mantle are discussed.

  11. Platinum-Group Element Mineralization in the Fedorovatundra layered intrusion, Kola Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Groshev, Nikolay; Subbotin, Victor; Korchagin, Alexey

    2016-04-01

    The 2526 to 2485 Ma Fedorovatundra layered mafic intrusion in the central part of the Kola Peninsula, Russia, is the western massif of the Fedorova-Pana Complex (2526-2446 Ma), which is situated along the northern contact of the Early Proterozoic Imandra-Varzuga rift and Archean granite gneiss. The Fedorovatundra intrusion of approximately 4 km thick has two major parts: (1) located at the bottom of the intrusion Taxitic series (10 to 900 m) and composing the main volume of the massif Layered series (4000 m). The Taxitic series is distinctive, due to its predominant vary-textured often quartz-saturated norites and gabbronorites (with fewer amounts of leucogabbro, melanorite and Ol-gabbronorite) and abundant pyroxenite, less harzburgite xenoliths. Medium to coarse-grained mottled or massive leucocratic gabbronorite and leucogabbro prevails in the Layered series with mesocratic gabbronorite, pyroxenite and troctolite as subordinate rocks. Depending on its localization, geochemical features, mineral composition and economic value platinum-group element (PGE) mineralization of the Fedorovatundra intrusion is divided into 'marginal' (basal, contact) and 'reef' types. 'Marginal' type of mineralization is presented by irregular disseminated interstitial sulfides (1-2 vol. %) of pentlandite-pyrrhotite-chalcopyrite association (Cu/Ni = 1.8) in the Taxitic series. Less sulfides occur as uniformly disseminated aggregates, thin massive lenses and nests. PGE and base metals are concentrated in several ore horizons of 3.5 km long complicated structure. Thickness of ore horizons varies generally within 10-150 m, but it can rise up to 280 m in bulges. In the most common ore-bearing rock (taxitic gabbronorite) average Pt + Pd content is 1.6 ppm (Pd/Pt 4.5). The pyroxenite xenoliths occurring within the Taxitic series are practically barren of sulfide and can dilute higher PGE and base metal grades in the gabbronorite matrix. 'Marginal' mineralization of the Fedorovotundrovsky

  12. Osmium-Isotope and Platinum-Group-Element Systematics of Impact-Melt Rocks, Chesapeake Bay Impact Structure, Virginia, USA

    NASA Technical Reports Server (NTRS)

    Lee, Seung Ryeol; Wright Horton, J., Jr.; Walker, Richard J.

    2005-01-01

    Osmium (Os) isotopes and platinum-group elements (PGEs) are useful for geochemically identifying a meteoritic component within impact structures, because meteorites are typically characterized by low (187)Os/(188)Os ratios and high PGE concentrations. In contrast, most types of crustal target rocks have high radiogenic Os and very low PGE concentrations. We have examined Os isotope and PGE systematics of impact-melt rocks and pre-impact target rocks from a 2004 test hole in the late Eocene Chesapeake Bay impact structure and from nearby coreholes. Our goal is to determine the proportion of the projectile component in the melt rock Additional information is included in the original extended abstract.

  13. Mobilization of the platinum group elements by low-temperature fluids: Implications for mineralization and the iridium controversy

    NASA Technical Reports Server (NTRS)

    Dowling, Kim; Keays, Reid R.; Wallace, Malcolm W.; Gostin, Victor A.

    1992-01-01

    Geochemical investigations on the widely dispersed Late Proterozoic Acraman impact ejecta horizon and its host marine shales in the Adelaide Geosyncline provide strong evidence for low-temperature mobilization of the platinum group elements (PGE), including Ir. The ejecta horizon was formed when the middle Proterozoic dacitic volcanics in the Gawler Ranges, central South Australia, were impacted by a very large (ca. 4 km) meteorite. The resulting structure, now represented by Lake Acraman, is Australia's largest meteorite impact structure. Debris from the impact was blasted for many hundreds of kilometers, some falling into the shallow sea of the Adelaide Geosyncline, some 300 km to the east of the impact site.

  14. pH-dependent release of trace elements including platinum group elements (PGEs) from gasoline and diesel catalysts

    NASA Astrophysics Data System (ADS)

    Sucha, Veronika; Mihaljevic, Martin; Ettler, Vojtech; Strnad, Ladislav

    2014-05-01

    The release of trace metals and platinum group elements (PGEs) from automobile exhaust catalysts represents a remarkable source of higly dispersed environmental contamination. Especially, PGEs have shown increasing research interest due to their possible bioaccessibility. In our research, we focused on leaching behaviour of trace metals from gasoline and diesel automobile catalysts. While catalysts for gasoline engines contain a mixture of Pt-Pd-Rh or Pd-Rh, catalysts for diesel engines are composed only of Pt. We used dust from two crushed gasoline and two crushed diesel catalysts (new and aged). The dust of gasoline catalysts contains significant concentrations of Pt (700 mg.kg-1), Pd (11 000 mg.kg-1) and Rh (700 mg.kg-1). And the dust of diesel catalysts are composed of Pt (3 900 mg.kg-1) and they contains negligible amounts of Pd dan Rh (< 0.5 mg.kg-1, < 0.1 mg.kg-1, respectively). To evaluate leaching of trace metals from dust we used pH-stat leaching test according to the European standard CEN/TS 14997. The concentrations of cations: PGEs (Pt, Pd a Rh), K, Na, Ca, Mg, Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, La and Ce were determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS), and anions: F-, Cl-, SO42- and NO3- by high-performance liquid chromatography. Although the dusts from catalysts were relatively stable to acid/base influence, the leaching of trace metals from catalysts showed a dependence on pH. Generally, the highest concentrations were released under acidic conditions. The leaching of PGEs was higher for Pt in diesel catalysts and for Pd and Rh in gasoline catalysts. The highest concentrations of Zn and Pb were observed in old catalysts. The rare earth metals were released more from gasoline catalysts. Catalysts particles represent health risk especially with respect to their PGEs contents.

  15. Platinum group elements geochemistry of ultramafic and associated rocks from Pindar in Madawara Igneous Complex, Bundelkhand massif, central India

    NASA Astrophysics Data System (ADS)

    Balaram, V.; Singh, S. P.; Satyanarayanan, M.; Anjaiah, K. V.

    2013-02-01

    Ultramafic rocks comprising dunite, harzburgite, lherzolite, olivine webserite and websterite occur as intrusives in the form of small hillocks at Pindar into the granite-gneisses of Bundelkhand Gneissic Complex (BnGC). The peridotites are dominated by olivine cumulates where chromite and precious metal-bearing sulphides crystallized along with pyroxenes, subsequent to crystallization of olivine into the interstitial spaces of cumulates during cooling. Ultramafic rocks of Pindar are characterized by high MgO (up to 46.0 wt%) and FeO (up to 5.8 wt%); low SiO2 (40.8 to 48.0 wt%), TiO2 (0.2 to 0.5 wt%), Al2O3 (~3.2 wt% av.), CaO (~2.7 wt% av.) and Cu (11 to 73 μg/g). Cr and Ni values range from 2297 to 3150 μg/g and 2434 to 2767 μg/g, respectively. Distribution of Ir (up to 20 ng/g), Ru (27 to 90 ng/g), Rh (3 to 14 ng/g), Pt (18 to 72 ng/g), Pd (10 to 27 ng/g) and Au (22 to 57 ng/g) indicate platinum group element (PGE) and associated gold mineralization in these ultramafic rocks. A mineral phase representing sperrylite (PtAs2) was also identified within the sulphides in scanning electron microscopy with energy dispersive spectrometer (SEM-EDS) studies. The primitive mantle-normalized siderophile elements pattern shows platinum group element PGE (PPGE) enrichment (Rh, Pt, Pd). Discrimination diagrams of Pd/Ir vs. Ni/Cu, Pd/Pt vs. Ni/Cu, Cu/Pd vs. Pd, and Cu vs. Pd for the peridotites of Pindar attribute to affinity towards komatiite magma, derived from high degree of partial melting of prolonged depleted mantle, and the sulphur saturation condition incurred during the crystallization of chromite which was favourable for PGE mineralization.

  16. Platinum-group elements in rocks from the voikar-syninsky ophiolite complex, Polar Urals, U.S.S.R.

    USGS Publications Warehouse

    Page, N.J.; Aruscavage, P. J.; Haffty, J.

    1983-01-01

    Analyses of platinum-group elements (PGE) in rocks collected from the Voikar-Syninsky ophiolite in the Polar Urals suggest that the distribution and geochemistry of PGE in this Paleozoic ophiolite are similar to those in Mesozoic ophiolites from elsewhere. Chondrite-normalized PGE patterns for chromitite, the tectonite unit, and ultramafic and mafic cumulate unit have negative slopes. These results are similar to those found for chromitites from other ophiolites; stratiform chromities show positive slopes. If the magmas that form both types of chromitite originate from similar mantle source material with respect to PGE content, the processes involved must be quite different. However, the distinct chondrite-normalized PGE patterns may reflect differing source materials. ?? 1983 Springer-Verlag.

  17. Efficient and Accurate Identification of Platinum-Group Minerals by a Combination of Mineral Liberation and Electron Probe Microanalysis with a New Approach to the Offline Overlap Correction of Platinum-Group Element Concentrations.

    PubMed

    Osbahr, Inga; Krause, Joachim; Bachmann, Kai; Gutzmer, Jens

    2015-10-01

    Identification and accurate characterization of platinum-group minerals (PGMs) is usually a very cumbersome procedure due to their small grain size (typically below 10 µm) and inconspicuous appearance under reflected light. A novel strategy for finding PGMs and quantifying their composition was developed. It combines a mineral liberation analyzer (MLA), a point logging system, and electron probe microanalysis (EPMA). As a first step, the PGMs are identified using the MLA. Grains identified as PGMs are then marked and coordinates recorded and transferred to the EPMA. Case studies illustrate that the combination of MLA, point logging, and EPMA results in the identification of a significantly higher number of PGM grains than reflected light microscopy. Analysis of PGMs by EPMA requires considerable effort due to the often significant overlaps between the X-ray spectra of almost all platinum-group and associated elements. X-ray lines suitable for quantitative analysis need to be carefully selected. As peak overlaps cannot be avoided completely, an offline overlap correction based on weight proportions has been developed. Results obtained with the procedure proposed in this study attain acceptable totals and atomic proportions, indicating that the applied corrections are appropriate.

  18. Distribution of platinum-group elements in the Bati Kef chromite deposit, Guleman-Elazig area, eastern Turkey.

    USGS Publications Warehouse

    Page, N.J.; Engin, T.; Singer, D.A.; Haffty, J.

    1984-01-01

    The distribution of platinum-group elements (PGE) within chromite deposits from an ophiolite is determined and their geochemistry compared with chromitites from ophiolites and from stratiform layered complexes elsewhere in the world. The Guleman area chromitites are lenses of layered massive to disseminated chromite in dunite or sheared harzburgite along and near the dunite-harzburgite contact. PGE were analysed by a fire assay/spectrographic method. The analyses, in ppb, varied narrowly near the detection limits; only Ir was mostly detected (24-27 ppb) . The data plot as independent, slight variations of individual PGE with crude and irregular spatial distributions, oriented with respect to the land surface. Based on studies elsewhere, the PGE reside mostly in laurite, erlichmanite and Os/Ir alloys included within or interstitial to chromite. Average values for each PGE were normalized with respect to average chondrite concentrations for these elements. All patterns for ophiolite-chromitites (5) show depletion of these elements relative to chondrite average concentrations, with greater depletion in Pt and Pd than in Ir and Ru, to produce patterns with negative slopes. Chromitites from differentiated stratiform complexes (2) yield patterns with positive slopes. -G.J.N.

  19. Platinum group element and cerium concentrations in roadside environments in Toronto, Canada.

    PubMed

    Wiseman, Clare L S; Hassan Pour, Zahra; Zereini, Fathi

    2016-02-01

    Platinum (Pt), palladium (Pd) and rhodium (Rh) are accumulating globally in the environment, due to their use as catalysts to control automotive exhaust emissions. While environmental increases in platinum metal concentrations have been well documented for a number of countries, published data for Canada have been missing to date. The aim of this study is to examine the concentrations of Pt, Pd and Rh, as well as Ce, in soils and dust as a function of traffic volume in Toronto, Ontario. Soils and road and underpass dust were collected from two sites with medium and high volumes of traffic. Samples were acid digested and co-precipitated with Hg (for Pd) and Te (for Pt and Rh), prior to measurement using ICP-Q-MS. Palladium occurred at the highest levels in samples, followed by Pt and Rh. Median concentrations for all soil samples were 63 μg Pd/kg, 8.7 μg Pt/kg, 1.7 μg Rh/kg and 41 mg Ce/kg. The results support existing data regarding PGE accumulation trends in urban and roadside environments, due to their use as catalysts in automotive catalytic converters. This study also confirms a shift toward the heavier use of Pd as the catalyst of choice in recent years, as reflected in the higher concentrations measured for this metal relative to Pt and Rh. The results highlight a need to continue monitoring the accumulation of PGE, most notably Pd, in urban environments.

  20. Batch leaching tests of motherboards to assess environmental contamination by bromine, platinum group elements and other selected heavy metals.

    PubMed

    Almeida, César; Grosselli, Melina; González, Patricia; Martínez, Dante; Gil, Raúl

    2016-02-01

    In this study, a batch leaching test was executed to evaluate the toxicity associated with chemicals contained in motherboards. The leaching solutions used were distilled water, nitric acid, acetic acid and synthetic acid rain solution. A total of 21 elements including Ag, As, Au, Br, Cd, Co, Cr, Cu, Hf, Ir, Mn, Ni, Os, Pb, Pd, Pt, Rd, Rh, Se, U and Zn were analyzed. In this study, the pH values of all the leachates fell within the range of 2.33-4.88. The highest concentrations of metals were obtained from the acid rain solution, whilst the maximum value of bromine was achieved with solution of acetic acid. Appreciable concentrations of platinum group elements were detected with concentrations around 3.45, 1.43, 1.21 and 22.19 µg L(-1) for Ir, Pd, Pt and Rh, respectively. The different leaching of the motherboards revealed the predominant presence of the toxic substances in the leached from the e-waste.

  1. Batch leaching tests of motherboards to assess environmental contamination by bromine, platinum group elements and other selected heavy metals.

    PubMed

    Almeida, César; Grosselli, Melina; González, Patricia; Martínez, Dante; Gil, Raúl

    2016-02-01

    In this study, a batch leaching test was executed to evaluate the toxicity associated with chemicals contained in motherboards. The leaching solutions used were distilled water, nitric acid, acetic acid and synthetic acid rain solution. A total of 21 elements including Ag, As, Au, Br, Cd, Co, Cr, Cu, Hf, Ir, Mn, Ni, Os, Pb, Pd, Pt, Rd, Rh, Se, U and Zn were analyzed. In this study, the pH values of all the leachates fell within the range of 2.33-4.88. The highest concentrations of metals were obtained from the acid rain solution, whilst the maximum value of bromine was achieved with solution of acetic acid. Appreciable concentrations of platinum group elements were detected with concentrations around 3.45, 1.43, 1.21 and 22.19 µg L(-1) for Ir, Pd, Pt and Rh, respectively. The different leaching of the motherboards revealed the predominant presence of the toxic substances in the leached from the e-waste. PMID:26343021

  2. Platinum group elements provide no indication of a meteoritic component in ICDP cores from the Bosumtwi crater, Ghana

    NASA Astrophysics Data System (ADS)

    Goderis, S.; Tagle, R.; Schmitt, R. T.; Erzinger, J.; Claeys, P. H.

    In an attempt to identify the type of projectile, 14 samples from the Bosumtwi crater in Ghana were analyzed for platinum group element (PGE) concentrations by nickel sulfide fire assay inductively coupled plasma-mass spectrometry (ICP-MS). The majority of the samples come from the impactite material recovered by cores LB-07A and LB-08A, which were drilled by the International Continental Scientific Drilling program (ICDP). One sample originates from the fallback material found at the contact between the impactite and the overlying lake sediment in core LB-05B. No clear signature of a meteoritic contamination was identified in the 13 impactite samples. The target rock apparently dominates the PGE contribution in the impactites. These results agree with the PGE concentrations reported for the suevites collected at the crater rim and in other parts of the Bosumtwi ICDP cores. However, based on Cr and Os isotopic signatures, a meteoritic component could be present in the sample of fallback material, supporting the reports of the existence of meteoritic material in the Ivory Coast tektites. Further analyses of the fallback material from the Bosumtwi drill cores should confirm (or not) this first result.

  3. Platinum group elements and gold in ferromanganese crusts from Afanasiy-Nikitin seamount, equatorial Indian Ocean: Sources and fractionation

    USGS Publications Warehouse

    Banakar, V.K.; Hein, J.R.; Rajani, R.P.; Chodankar, A.R.

    2007-01-01

    The major element relationships in ferromanganese (Fe-Mn) crusts from Afanasiy-Nikitin seamount (ANS), eastern equatorial Indian Ocean, appear to be atypical. High positive correlations (r = 0.99) between Mn/Co and Fe/Co ratios, and lack of correlation of those ratios with Co, Ce, and Ce/Co, indicate that the ANS Fe-Mn crusts are distinct from Pacific seamount Fe-Mn crusts, and reflect region-specific chemical characteristics. The platinum group elements (PGE: Ir, Ru, Rh, Pt, and Pd) and Au in ANS Fe-Mn crusts are derived from seawater and are mainly of terrestrial origin, with a minor cosmogenic component. The Ru/Rh (0.5-2) and Pt/Ru ratios (7-28) are closely comparable to ratios in continental basalts, whereas Pd/Ir ratios exhibit values ( 0.75) correlations between water depth and Mn/Co, Fe/Co, Ce/Co, Co, and the PGEs. Fractionation of the PGE-Au from seawater during colloidal precipitation of the major-oxide phases is indicated by well-defined linear positive correlations (r > 0.8) of Co and Ce with Ir, Ru, Rh, and Pt; Au/Co with Mn/Co; and by weak or no correlations of Pd with water depth, Co-normalized major-element ratios, and with the other PGE (r < 0.5). The strong enrichment of Pt (up to 1 ppm) relative to the other PGE and its positive correlations with Ce and Co demonstrate a common link for the high concentrations of all three elements, which likely involves an oxidation reaction on the Mn-oxide and Fe-oxyhydroxide surfaces. The documented fractionation of PGE-Au and their positive association with redox sensitive Co and Ce may have applications in reconstructing past-ocean redox conditions and water masses.

  4. The origin of halide melt phases in layered intrusions, and their significance to platinum-group element mobility

    NASA Astrophysics Data System (ADS)

    Hanley, J. J.

    2007-12-01

    Fluid and melt inclusions are preserved within pegmatite bodies and cumulus minerals within mafic-ultramafic layered intrusions that host economic concentrations of the platinum-group elements (e.g., Bushveld Complex, South Africa; Stillwater Complex, Montana). The inclusions indicate that the earliest volatile phase to have exsolved from the crystallizing intrusions was a relatively anhydrous carbonic fluid (CO2-dominated). As crystallization proceeded, volatiles became increasingly water-rich and saline, consistent with the relative saturation limits of carbonic and aqueous fluids in mafic silicate liquids, and the partitioning behavior of Cl in fluid-melt systems. Previously unreported, the latest stage volatiles in the layered intrusions were halide melts (slightly hydrous molten salts) of relatively simply composition (NaCl with minor KCl or CaCl2) with salinities in excess of 90 wt% eq. NaCl or CaCl2. These volatiles were trapped at minimum temperatures of 760-800°C, near the eutectic temperature for water-saturated granitic liquid at moderate crustal pressures. Trace element analysis of the salt melt inclusions by laser ablation ICP-MS (ETH Zürich) show that they contain no detectable concentrations of ore and accessory metals. This is in contrast to the earlier, lower salinity volatiles which contain ppm-concentrations of Pt, Pd, As, Bi, Sb as well as abundant S and base metals. Heterogeneous entrapment of late-stage silicate melt and halide melt provides unambiguous evidence for the coexistence of both phases. However, experimental constraints on the nature of exsolved volatiles from mafic or felsic silicate liquids suggest that the halide melt phases cannot represent an exsolved phase from that coexisting silicate liquid, since this would require unrealistically high (initial) Cl:H2O ratios for the parental silicate liquid (> 9 for a granitic residue). Analysis of rhyodacitic silicate melt inclusions that coexist with the halide melt inclusions show

  5. Platinum-group elements and minerals in the lower and middle group chromitites of the western Bushveld Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Junge, Malte; Oberthür, Thomas; Osbahr, Inga; Gutter, Paul

    2016-08-01

    The chromitites of the Bushveld Complex in South Africa contain vast resources of platinum-group elements (PGE). However, knowledge of the distribution and the mineralogical siting of the PGE in the lower group (LG) and middle group (MG) chromitite seams of the Bushveld Complex is limited. We studied concentrates from the LG-6 and MG-2 chromitites of the western Bushveld Complex by a variety of microanalytical techniques. The dominant PGM are sulfides, namely laurite, cooperite-braggite, and malanite-cuprorhodsite, followed by PGE-sulfarsenides, sperrylite, and Pt-Fe alloys. Laurite is the most abundant PGM (vol%). The matching sets of PGM present in the LG and MG chromitites of both the western and the eastern Bushveld Complex, and in the UG-2 chromitite, show strong similarities which support the assumption of a characteristic and general chromitite-related PGM assemblage. Palladium and Rh contents in pentlandite are low and erratic although maximum contents of 7730 ppm Pd and 6020 ppm Rh were detected. Rare thiospinels of the polydymite-linnaeite-greigite series have PGE contents of 1430 ppm Pt, 5370 ppm Rh, and 1460 ppm Pd. The various PGE occur in different deportment: Platinum is generally present in the form of discrete PGM (sulfides, arsenides, alloys). Palladium is present as a large variety of discrete PGM and also incorporated in pentlandite. Rhodium forms discrete PGM and is occasionally present in pentlandite. The IPGE (Os, Ir, and Ru) are dominantly incorporated in laurite (often as inclusions in chromite) and also occur as sulfarsenides.

  6. Anthropogenic platinum group element (Pt, Pd, Rh) concentrations in PM10 and PM2.5 from Kolkata, India.

    PubMed

    Diong, Huey Ting; Das, Reshmi; Khezri, Bahareh; Srivastava, Bijayen; Wang, Xianfeng; Sikdar, Pradip K; Webster, Richard D

    2016-01-01

    This study investigates platinum group elements (PGEs) in the breathable (PM10) and respirable (PM2.5) fractions of air particulates from a heavily polluted Indian metro city. The samples were collected from traffic junctions at the heart of the city and industrial sites in the suburbs during winter and monsoon seasons of 2013-2014. PGE concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The PGE concentrations in the samples from traffic junctions are within the range of 2.7-111 ng/m(3) for Pd, 0.86-12.3 ng/m(3) for Pt and 0.09-3.13 ng/m(3) for Rh, and from industrial sites are within the range of 3.12-32.3 ng/m(3) for Pd, 0.73-7.39 ng/m(3) for Pt and 0.1-0.69 ng/m(3) for Rh. Pt concentrations were lower in the monsoon compared to winter while Pd concentrations increased during monsoon and Rh stayed relatively unaffected across seasons. For all seasons and locations, concentrations of Pd > Pt > Rh, indicating dominance of Pd-containing exhaust converters. Most of the PGEs were concentrated in the PM2.5 fraction. A strong correlation (R ≥ 0.62) between the PGEs from traffic junction indicates a common emission source viz. catalytic converters, whereas a moderate to weak correlation (R ≤ 0.5) from the industrial sites indicate mixing of different sources like coal, raw materials used in the factories and automobile. A wider range of Pt/Pd, Pt/Rh and Pd/Rh ratios measured in the traffic junction possibly hint towards varying proportions of PGEs used for catalyst productions in numerous rising and established car brands. PMID:27536525

  7. Re-Os isotope and platinum group elements of a FOcal ZOne mantle source, Louisville Seamounts Chain, Pacific ocean

    NASA Astrophysics Data System (ADS)

    Tejada, Maria Luisa G.; Hanyu, Takeshi; Ishikawa, Akira; Senda, Ryoko; Suzuki, Katsuhiko; Fitton, Godfrey; Williams, Rebecca

    2015-02-01

    The Louisville Seamount Chain (LSC) is, besides the Hawaiian-Emperor Chain, one of the longest-lived hotspot traces. We report here the first Re-Os isotope and platinum group element (PGE) data for Canopus, Rigil, and Burton Guyots along the chain, which were drilled during IODP Expedition 330. The LSC basalts possess (187Os/188Os)i = 0.1245-0.1314 that are remarkably homogeneous and do not vary with age. A Re-Os isochron age of 64.9 ± 3.2 Ma was obtained for Burton seamount (the youngest of the three seamounts drilled), consistent with 40Ar-39Ar data. Isochron-derived initial 187Os/188Os ratio of 0.1272 ± 0.0008, together with data for olivines (0.1271-0.1275), are within the estimated primitive mantle values. This (187Os/188Os)i range is similar to those of Rarotonga (0.124-0.139) and Samoan shield (0.1276-0.1313) basalts and lower than those of Cook-Austral (0.136-0.155) and Hawaiian shield (0.1283-0.1578) basalts, suggesting little or no recycled component in the LSC mantle source. The PGE data of LSC basalts are distinct from those of oceanic lower crust. Variation in PGE patterns can be largely explained by different low degrees of melting under sulfide-saturated conditions of the same relatively fertile mantle source, consistent with their primitive mantle-like Os and primordial Ne isotope signatures. The PGE patterns and the low 187Os/188Os composition of LSC basalts contrast with those of Ontong Java Plateau (OJP) tholeiites. We conclude that the Re-Os isotope and PGE composition of LSC basalts reflect a relatively pure deep-sourced common mantle sampled by some ocean island basalts but is not discernible in the composition of OJP tholeiites.

  8. Platinum-group elements and minerals in the lower and middle group chromitites of the western Bushveld Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Junge, Malte; Oberthür, Thomas; Osbahr, Inga; Gutter, Paul

    2016-10-01

    The chromitites of the Bushveld Complex in South Africa contain vast resources of platinum-group elements (PGE). However, knowledge of the distribution and the mineralogical siting of the PGE in the lower group (LG) and middle group (MG) chromitite seams of the Bushveld Complex is limited. We studied concentrates from the LG-6 and MG-2 chromitites of the western Bushveld Complex by a variety of microanalytical techniques. The dominant PGM are sulfides, namely laurite, cooperite-braggite, and malanite-cuprorhodsite, followed by PGE-sulfarsenides, sperrylite, and Pt-Fe alloys. Laurite is the most abundant PGM (vol%). The matching sets of PGM present in the LG and MG chromitites of both the western and the eastern Bushveld Complex, and in the UG-2 chromitite, show strong similarities which support the assumption of a characteristic and general chromitite-related PGM assemblage. Palladium and Rh contents in pentlandite are low and erratic although maximum contents of 7730 ppm Pd and 6020 ppm Rh were detected. Rare thiospinels of the polydymite-linnaeite-greigite series have PGE contents of 1430 ppm Pt, 5370 ppm Rh, and 1460 ppm Pd. The various PGE occur in different deportment: Platinum is generally present in the form of discrete PGM (sulfides, arsenides, alloys). Palladium is present as a large variety of discrete PGM and also incorporated in pentlandite. Rhodium forms discrete PGM and is occasionally present in pentlandite. The IPGE (Os, Ir, and Ru) are dominantly incorporated in laurite (often as inclusions in chromite) and also occur as sulfarsenides.

  9. Anthropogenic platinum group element (Pt, Pd, Rh) concentrations in PM10 and PM2.5 from Kolkata, India.

    PubMed

    Diong, Huey Ting; Das, Reshmi; Khezri, Bahareh; Srivastava, Bijayen; Wang, Xianfeng; Sikdar, Pradip K; Webster, Richard D

    2016-01-01

    This study investigates platinum group elements (PGEs) in the breathable (PM10) and respirable (PM2.5) fractions of air particulates from a heavily polluted Indian metro city. The samples were collected from traffic junctions at the heart of the city and industrial sites in the suburbs during winter and monsoon seasons of 2013-2014. PGE concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The PGE concentrations in the samples from traffic junctions are within the range of 2.7-111 ng/m(3) for Pd, 0.86-12.3 ng/m(3) for Pt and 0.09-3.13 ng/m(3) for Rh, and from industrial sites are within the range of 3.12-32.3 ng/m(3) for Pd, 0.73-7.39 ng/m(3) for Pt and 0.1-0.69 ng/m(3) for Rh. Pt concentrations were lower in the monsoon compared to winter while Pd concentrations increased during monsoon and Rh stayed relatively unaffected across seasons. For all seasons and locations, concentrations of Pd > Pt > Rh, indicating dominance of Pd-containing exhaust converters. Most of the PGEs were concentrated in the PM2.5 fraction. A strong correlation (R ≥ 0.62) between the PGEs from traffic junction indicates a common emission source viz. catalytic converters, whereas a moderate to weak correlation (R ≤ 0.5) from the industrial sites indicate mixing of different sources like coal, raw materials used in the factories and automobile. A wider range of Pt/Pd, Pt/Rh and Pd/Rh ratios measured in the traffic junction possibly hint towards varying proportions of PGEs used for catalyst productions in numerous rising and established car brands.

  10. Platinum Group Elements (PGE) geochemistry of komatiites and boninites from Dharwar Craton, India: Implications for mantle melting processes

    NASA Astrophysics Data System (ADS)

    Saha, Abhishek; Manikyamba, C.; Santosh, M.; Ganguly, Sohini; Khelen, Arubam C.; Subramanyam, K. S. V.

    2015-06-01

    High MgO volcanic rocks having elevated concentrations of Ni and Cr are potential hosts for platinum group elements (PGE) owing to their primitive mantle origin and eruption at high temperatures. Though their higher PGE abundance is economically significant in mineral exploration studies, their lower concentrations are also valuable geochemical tools to evaluate petrogenetic processes. In this paper an attempt has been made to evaluate the PGE geochemistry of high MgO volcanic rocks from two greenstone belts of western and eastern Dharwar Craton and to discuss different mantle processes operative at diverse geodynamic settings during the Neoarchean time. The Bababudan greenstone belt of western and Gadwal greenstone belt of eastern Dharwar Cratons are dominantly composed of high MgO volcanic rocks which, based on distinct geochemical characteristics, have been identified as komatiites and boninites respectively. The Bababudan komatiites are essentially composed of olivine and clinopyroxene with rare plagioclase tending towards komatiitic basalts. The Gadwal boninites contain clinopyroxene, recrystallized hornblende with minor orthopyroxene, plagioclase and sulphide minerals. The Bababudan komatiites are Al-undepleted type (Al2O3/TiO2 = 23-59) with distinctly high MgO (27.4-35.8 wt.%), Ni (509-1066 ppm) and Cr (136-3036 ppm) contents. These rocks have low ΣPGE (9-42 ppb) contents with 0.2-2.4 ppb Iridium (Ir), 0.2-1.4 ppb Osmium (Os) and 0.4-4.4 ppb Ruthenium (Ru) among Iridium group PGE (IPGE); and 1.4-16.2 ppb Platinum (Pt), 2.8-19 ppb Palladium (Pd) and 0.2-9.8 ppb Rhodium (Rh) among Platinum group PGE (PPGE). The Gadwal boninites are high-Ca boninites with CaO/Al2O3 ratios varying between 0.8 and 1.0, with 12-24 wt.% MgO, 821-1168 ppm Ni and 2307-2765 ppm Cr. They show higher concentration of total PGE (82-207 ppb) with Pt concentration ranging from 13 to 19 ppb, Pd between 65 and 180 ppb and Rh in the range of 1.4-3 ppb compared to the Bababudan komatiites. Ir

  11. Platinum group and chalcophile element systematics of serpentinized peridotites from the St. Elena ophiolite in Costa Rica

    NASA Astrophysics Data System (ADS)

    Holm, J.; Bizimis, M.; Schwarzenbach, E. M.; Foustoukos, D.; Frisby, C. P.; Brandon, A. D.; Gazel, E.

    2015-12-01

    We present in situ LA-ICPMS data on platinum group element (PGE) and chalcophile element (namely Cu, Ag, Te, Au, Pb) systematics in sulfides from partially serpentinized peridotites of the St. Elena ophiolite, Costa Rica. PGE are strong indicators of primary mantle processes, though their behavior during low temperature alteration processes such as serpentinization is not well understood. St. Elena sulfides are dominantly pentlandites that coexist with Fe-Ni alloys and native Cu. This indicates extremely low fO2 and fS2 conditions likely established during the early stages of serpentinization. We observe extremely variable PGE-Re concentrations in the sulfides, (e.g. [Os] = 2 - 100,000 times primitive mantle, PM). Low [Os] sulfides have high Pd/Os, which in turn correlates positively with Cu concentrations, suggesting Pd enrichment through Cu-rich fluids (e.g. Schwarzenbach et al., 2014, CMP) as opposed to melt-rock reaction. Sulfide PM-normalized PGE-Re patterns are dominated by strong Pt depletions (e.g., Pt/Pd = 0.80-0.0009). Occasional Pt enrichments over Pd and Ru (or Rh) in a PM-normalized pattern (~5% of the sulfide population) often correlate with Te and/or Au enrichments. Pt enrichment was also observed in a composite pentlandite-awaruite, suggesting possible exsolution of Pt from sulfides under extremely low fS2 conditions. Pb concentrations do not correlate with other chalcophiles or PGE. Pb ranges from 0.01-31.64 ppm with the majority of sulfides <5 ppm, and an average concentration of 2.77 ppm (n=64). Assuming that this Pb concentration is representative of mantle sulfides, this implies that Pb is not dominantly held in sulfides in the upper mantle. Combination of in situ and bulk rock PGE analyses will be used to distinguish the effects of primary magmatic signatures (e.g., melt depletion, melt-rock interaction) and secondary processes such as serpentinization on the PGE-Re and chalcophile element systematics of these sulfides.

  12. Platinum-group element concentrations in pyrite from the Main Sulfide Zone of the Great Dyke of Zimbabwe

    NASA Astrophysics Data System (ADS)

    Piña, R.; Gervilla, F.; Barnes, S.-J.; Oberthür, T.; Lunar, R.

    2016-02-01

    The Main Sulfide Zone (MSZ) of the Great Dyke of Zimbabwe hosts the world's second largest resource of platinum-group elements (PGE) after the Bushveld Complex in South Africa. The sulfide assemblage of the MSZ comprises pyrrhotite, pentlandite, chalcopyrite, and minor pyrite. Recently, several studies have observed in a number of Ni-Cu-PGE ore deposits that pyrite may host significant amounts of PGE, particularly Pt and Rh. In this study, we have determined PGE and other trace element contents in pyrite from the Hartley, Ngezi, Unki, and Mimosa mines of the Great Dyke by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Based on the textures and PGE contents, two types of pyrite can be differentiated. Py1 occurs as individual euhedral or subhedral grains or clusters of crystals mostly within chalcopyrite and pentlandite, in some cases in the form of symplectitic intergrowths, and is PGE rich (up to 99 ppm Pt and 61 ppm Rh; 1.7 to 47.1 ppm Ru, 0.1 to 7.8 ppm Os, and 1.2 to 20.2 ppm Ir). Py2 occurs as small individual euhedral or subhedral crystals within pyrrhotite, pentlandite, and less frequently within chalcopyrite and silicates and has low PGE contents (<0.11 ppm Pt, <0.34 ppm Rh, <2.5 ppm Ru, <0.37 ppm Ir, and <0.40 ppm Os). Py1 contains higher Os, Ir, Ru, Rh, and Pt contents than the associated pyrrhotite, pentlandite, and chalcopyrite, whereas Py2 has similar PGE contents as coexisting pyrrhotite and pentlandite. Based on the textural relationships, two different origins are attributed for each pyrite type. Py1 intergrowth with pentlandite and chalcopyrite is inferred to have formed by late, low temperature (<300 °C) decomposition of residual Ni-rich monosulfide solid solution, whereas Py2 is suggested to have formed by replacement of pyrrhotite and pentlandite caused by late magmatic/hydrothermal fluids.

  13. Platinum-group element concentrations in pyrite from the Main Sulfide Zone of the Great Dyke of Zimbabwe

    NASA Astrophysics Data System (ADS)

    Piña, R.; Gervilla, F.; Barnes, S.-J.; Oberthür, T.; Lunar, R.

    2016-10-01

    The Main Sulfide Zone (MSZ) of the Great Dyke of Zimbabwe hosts the world's second largest resource of platinum-group elements (PGE) after the Bushveld Complex in South Africa. The sulfide assemblage of the MSZ comprises pyrrhotite, pentlandite, chalcopyrite, and minor pyrite. Recently, several studies have observed in a number of Ni-Cu-PGE ore deposits that pyrite may host significant amounts of PGE, particularly Pt and Rh. In this study, we have determined PGE and other trace element contents in pyrite from the Hartley, Ngezi, Unki, and Mimosa mines of the Great Dyke by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Based on the textures and PGE contents, two types of pyrite can be differentiated. Py1 occurs as individual euhedral or subhedral grains or clusters of crystals mostly within chalcopyrite and pentlandite, in some cases in the form of symplectitic intergrowths, and is PGE rich (up to 99 ppm Pt and 61 ppm Rh; 1.7 to 47.1 ppm Ru, 0.1 to 7.8 ppm Os, and 1.2 to 20.2 ppm Ir). Py2 occurs as small individual euhedral or subhedral crystals within pyrrhotite, pentlandite, and less frequently within chalcopyrite and silicates and has low PGE contents (<0.11 ppm Pt, <0.34 ppm Rh, <2.5 ppm Ru, <0.37 ppm Ir, and <0.40 ppm Os). Py1 contains higher Os, Ir, Ru, Rh, and Pt contents than the associated pyrrhotite, pentlandite, and chalcopyrite, whereas Py2 has similar PGE contents as coexisting pyrrhotite and pentlandite. Based on the textural relationships, two different origins are attributed for each pyrite type. Py1 intergrowth with pentlandite and chalcopyrite is inferred to have formed by late, low temperature (<300 °C) decomposition of residual Ni-rich monosulfide solid solution, whereas Py2 is suggested to have formed by replacement of pyrrhotite and pentlandite caused by late magmatic/hydrothermal fluids.

  14. Positive anomaly in platinum group elements and the presence of shocked diamonds: Two question marks at the Younger Dryas

    NASA Astrophysics Data System (ADS)

    Claeys, P. F.; Schryvers, D.; Tian, H.; Goderis, S.

    2009-12-01

    Recently, a large size impact was proposed as the cause of the global changes taking place at the Younger Dryas (YD) some 12,9 kyr ago. Impact evidence was reported in a C-rich black layer of broad geographic distribution. The impact markers consist of a large anomaly in the concentration of platinum group elements (PGE) and the presence of nanodiamonds, in particular lonsdaleite, which hexagonal structure is believed to be of shock origin. The impact is proposed to have occurred on the North American continent. A crater large enough (> 150 km) to induce a mass extinction some ~12.9 ka ago, formed in a geologically well-known area, is unlikely to have escaped detection. Therefore, an alternative hypothesis is that a cometary projectile exploded fully within the atmosphere spreading PGE and shock formed diamonds, without any target rock contribution, all around the Northern hemisphere. So far, PGE measurements failed to reproduce the elevated (> ppb) concentrations reported previously at Younger Dryas sites containing the black layer. In Lommel (Belgium) where the first study detected up to 117 ppb Ir, the Ir concentration is below the detection limit of the method (NiS fire assay + ICP-MS) used (0.06 ppb). At all sites analyzed the PGE pattern is typical of that of the continental crust. In several craters (Popigai, Ries) or at the KT boundary nanodiamonds have been reported associated with shocked materials. Several types of carbon components occur in the black layer of the Lommel section such as i) flakes reaching up to 1 µm, ii) nano particles of cubic diamond, 1 to 10 nm in size and iii) larger carbon onion-ring structures, which core can act as a nanoscopic pressure cell leading to the formation of nanodiamond by self- compression. The Lommel nanodiamonds present in the Younger Dryas layer do resemble nanodiamonds found in carbon spherules of unknown origin previously reported in top soil from several localities in Belgium and Germany. The C stable isotopic

  15. Platinum-group element abundance and distribution in chromite deposits of the Acoje Block, Zambales Ophiolite Complex, Philippines

    USGS Publications Warehouse

    Bacuta, G.C.; Kay, R.W.; Gibbs, A.K.; Lipin, B.R.

    1990-01-01

    Platinum-group elements (PGE) occur in ore-grade concentration in some of the chromite deposits related to the ultramafic section of the Acoje Block of the Zambales Ophiolite Complex. The deposits are of three types: Type 1 - associated with cumulate peridotites at the base of the crust; Type 2 - in dunite pods from the top 1 km of mantle harzburgite; and Type 3 - like Type 2, but in deeper levels of the harzburgite. Most of the deposites have chromite compositions that are high in Cr with Cr/(Cr + Al) (expressed as chromium index, Cr#) > 0.6; high-Al (Cr# Pd, thought to be characteristic of PGE-barren deposits) and positive slope (Ir < Pd, characteristic of PGE-rich deposits). Iridium, Ru and Os commonly occur as micron-size laurite (sulfide) inclusions in unfractured chromite. Laurite and native Os are also found as inclusions in interstitial sulfides. Platinum and Pd occur as alloy inclusions (and possibly as solid solution) in interstitial Ni-Cu sulfides and as tellurobismuthides in serpentine and altered sulfides. Variability of PGE distribution may be explained by alteration, crystal fractionation or partial melting processes. Alteration and metamorphism were ruled out, because PGE contents do not correlate with degree of serpentinization or the abundance and type (hydroxyl versus non-hydroxyl) of silicate inclusions in chromite. Preliminary Os isotopic data do not support crustal contamination as a source of the PGEs in the Acoje deposits. The anomalous PGE concentrations in Type 1 high-Cr chromite deposits are attributed to two stages of enrichment: an early enrichment of their mantle source from previous melting events and a later stage of sulfide segregation accompanying chromite crystallization. High-Al chromite deposits which crystallized from basalts derived from relatively low degrees of melting owe their low PGE content to partitioning of PGEs in sulfides and alloys that remain in the mantle. High-Cr deposits crystallized from melts that were

  16. Concentration and distribution of platinum group elements (Pt, Pd, Rh) in airborne particulate matter in Frankfurt am Main, Germany.

    PubMed

    Zereini, Fathi; Alt, Friedrich; Messerschmidt, Jürge; von Bohlen, Alex; Liebl, Karlheinz; Püttmann, Wilhelm

    2004-03-15

    The concentrations and distribution of platinum group elements (Pt, Pd, Rh) in airborne particulate matter were studied in a period of one year from August 2001 to July 2002 in urban and in nonurban areas. Airborne dust samples were collected as a total amount (particles with an aerodynamic diameter <22 microm) and classified using an eight-stage Andersen impactor (<10 microm) at three locations with different traffic density roads in the Frankfurt am Main and nonurban areas. Sampling at the three locations was performed simultaneously for total airborne dust and fractionated airborne dust. Pd was determined by total reflection X-ray fluorescence after Hg coprecipitation. Pt and Rh were analyzed by adsorptive striping voltammetry after HPA digestion. The results show that the PGE concentrations in airborne samples depend on the traffic density. The highest PGE concentrations in air were found in the vicinity of major roads with heavy traffic, and the lowest ones were found in the nonurban area. The presence of PGE at the sampling station relatively free of traffic in a nonurban area hints to a transport of some of the emitted PGE from the city to this station by wind. At all three sampling locations, a heterogeneous distribution of the Pd, Pt, and Rh concentrations during the sampling year can be observed. The sum of PGE concentrations in total airborne dust is comparable with the sum of impactor samples. However, the concentration of Pt and Rh in total airborne dust (<22 microm) is on average higher than in impactor samples (<10 microm). On the contrary, Pd concentration is higher in impactor samples in most cases. The airborne PGE distribution is dominated by Pt, followed by Pd and Rh. The impactor samples are dominated by Pd, followed by Pt and Rh. This fact indicates that palladium occurs mainly in relatively fine airborne particles. The main fraction of PGE is found on average in particle sizes between 1.1 and 4.7 microm. Knowledge of the size distribution of

  17. Ni, Cu, Au, and platinum-group element contents of sulphides associated with intraplate magmatism: A synthesis

    USGS Publications Warehouse

    Barnes, S.-J.; Zientek, M.L.; Severson, M.J.

    1997-01-01

    The tectonic setting of intraplate magmas, typically a plume intersecting a rift, is ideal for the development of Ni - Cu - platinum-group element-bearing sulphides. The plume transports metal-rich magmas close to the mantle - crust boundary. The interaction of the rift and plume permits rapid transport of the magma into the crust, thus ensuring that no sulphides are lost from the magma en route to the crust. The rift may contain sediments which could provide the sulphur necessary to bring about sulphide saturation in the magmas. The plume provides large volumes of mafic magma; thus any sulphides that form can collect metals from a large volume of magma and consequently the sulphides will be metal rich. The large volume of magma provides sufficient heat to release large quantities of S from the crust, thus providing sufficient S to form a large sulphide deposit. The composition of the sulphides varies on a number of scales: (i) there is a variation between geographic areas, in which sulphides from the Noril'sk - Talnakh area are the richest in metals and those from the Muskox intrusion are poorest in metals; (ii) there is a variation between textural types of sulphides, in which disseminated sulphides are generally richer in metals than the associated massive and matrix sulphides; and (iii) the massive and matrix sulphides show a much wider range of compositions than the disseminated sulphides, and on the basis of their Ni/Cu ratio the massive and matrix sulphides can be divided into Cu rich and Fe rich. The Cu-rich sulphides are also enriched in Pt, Pd, and Au; in contrast, the Fe-rich sulphides are enriched in Fe, Os, Ir, Ru, and Rh. Nickel concentrations are similar in both. Differences in the composition between the sulphides from different areas may be attributed to a combination of differences in composition of the silicate magma from which the sulphides segregated and differences in the ratio of silicate to sulphide liquid (R factors). The higher metal

  18. Biological role in the transformation of platinum-group mineral grains

    NASA Astrophysics Data System (ADS)

    Reith, Frank; Zammit, Carla M.; Shar, Sahar S.; Etschmann, Barbara; Bottrill, Ralph; Southam, Gordon; Ta, Christine; Kilburn, Matthew; Oberthür, Thomas; Ball, Andrew S.; Brugger, Joël

    2016-04-01

    Platinum-group elements are strategically important metals. Finding new deposits is becoming increasingly difficult owing to our limited understanding of the processes that affect their mobility in surface environments. Microorganisms have been shown to promote the mobility of metals around ore deposits. Here we show that microorganisms influence the mobility of platinum-group elements in mineral grains collected from Brazil, Australia and Colombia. Scanning electron microscopy showed biofilms covering the platinum-group mineral grains. The biofilms contained abundant platinum-group element nanoparticles and microcrystalline aggregates, and were dominated by Proteobacteria, many of which were closely related to known metal-resistant species. Some platinum-group mineral grains contained carbon, nitrogen, sulfur, selenium and iodine, suggesting the grains may be biogenic in origin. Molecular analyses show that Brazilian platinum-palladium grains hosted specific bacterial communities, which were different in composition from communities associated with gold grains, or communities in surrounding soils and sediments. Nano-phase metallic platinum accumulated when a metallophillic bacterium was incubated with a percolating platinum-containing medium, suggesting that biofilms can cause the precipitation of mobile platinum complexes. We conclude that biofilms are capable of forming or transforming platinum-group mineral grains, and may play an important role for platinum-group element dispersion and re-concentration in surface environments.

  19. Sniffing for Clues to the Dinosaurs Demise: Measurement of Osmium Isotope Compositions and Platinum Group Element Abundances in Volcanic Emissions

    NASA Astrophysics Data System (ADS)

    Sims, K. W.; Peucker-Ehrenbrink, B.; Mather, T.; Pyle, D.; Martin, R.; Gauthier, P.; Aiuppa, A.

    2005-12-01

    Platinum Group Elements (PGE: Os, Ir, Rh, Ru, Pt, Pd) and osmium isotopes measured in marine and terrestrial sediment, snow and ice records are important paleo-tracers of riverine, hydrothermal, extraterrestrial, volcanic and anthropogenic inputs into the global surficial environment. For instance, the marine Os isotope record across the Cretaceous-Tertiary Boundary (KTB) indicates that the onset of the main phase of Deccan volcanism and the transient late Maastrichtian warming preceded the large extraterrestrial impact and the related KTB mass extinction by several hundred thousand years [Ravizza and Peucker-Ehrenbrink, 2003]. Distinguishing extraterrestrial from volcanic PGE sources has been difficult due to the similarity in Os isotopic compositions, complex PGE fractionations, and our lack of knowledge of the Os isotopic composition and PGE abundances in volcanic aerosols. These difficulties have fueled vigorous debate about extraterrestrial vs. volcanic triggers of mass extinctions in the geologic record. To assess the volcanic contribution to the global Re-Os-PGE cycle we have initiated a study of Os isotopic compositions and PGE abundances in volcanic emissions from volcanoes around the globe. Here we report preliminary data on PGE abundances and Os isotopes measured in gas and aerosol filter samples from Vulcan Masaya, Nicaragua and Mt Etna, Italy. Samples were analyzed by ID-ICPMS (ThermoFinnigan ELEMENT 2 and NEPTUNE) at the Woods Hole Oceanographic Institution. Osmium isotope compositions of the filters are unradiogenic (0.1272 to 0.187). Osmium concentrations range from 28 to 97 pg/cubic meter and are 3-4 orders of magnitude lower than those measured by Krahenbuhl et al. [1992] during the spring 1984 eruption of Mauna Loa just after the lava fountaining phase. Normalized PGE abundance patterns are fractionated relative to carbonaceous chondrites and two important features distinguish the pattern from other important PGE sources: 1) Os/Ir is much higher

  20. Evidence from meimechites and other low-degree mantle melts for redox controls on mantle-crust fractionation of platinum-group elements

    PubMed Central

    Mungall, James E.; Hanley, Jacob J.; Arndt, Nicholas T.; Debecdelievre, Anne

    2006-01-01

    Understanding of the geochemistry of the chalcophile elements [i.e., Os, Ir, Ru, Pt, Pd (platinum-group elements), and Au, Cu, Ni] has been informed for at least 20 years by the common assumption that when crust-forming partial melts are extracted from the upper mantle, sulfide liquid in the restite sequesters chalcophile elements until the extent of partial melting exceeds ≈25% and all of the sulfide has been dissolved in silicate melt [Hamlyn, P. R. & Keays, R. R. (1985) Geochim. Cosmochim. Acta 49, 1797–1811]. Here we document very high, unfractionated, chalcophile element concentrations in small-degree partial melts from the mantle that cannot be reconciled with the canonical residual sulfide assumption. We show that the observed high, unfractionated platinum-group element concentrations in small-degree partial melts can be attained if the melting takes place at moderately high oxygen fugacity, which will reduce the amount of sulfide due to the formation of sulfate and will also destabilize residual monosulfide solid solution by driving sulfide melts into the spinel-liquid divariant field. Magmas formed at high oxygen fugacity by small degrees of mantle melting can be important agents for the transfer of chalcophile elements from the upper mantle to the crust and may be progenitors of significant ore deposits of Pt, Pd, and Au. PMID:16908861

  1. Partitioning of platinum-group elements and Au between sulfide liquid and basalt and the origins of mantle-crust fractionation of the chalcophile elements

    NASA Astrophysics Data System (ADS)

    Mungall, James E.; Brenan, James M.

    2014-01-01

    The partitioning of platinum-group elements (PGE; Os, Ir, Ru, Rh, Pt, and Pd) and Au between sulfide melt and silicate melt (i.e., DPGEsul) exerts a critical control on the PGE composition of the Earth’s crust and mantle, but previous estimates have been plagued by experimental uncertainties and vary through several orders of magnitude. Here we present direct experimental measurements of DPGEsul, based on in situ microanalysis of the sulfide and silicate melt, with values ranging from ∼4 × 105 (Ru) to ∼2-3 × 106 (Ir, Pt). Our measurements of DPGEsul are >100 times larger than previous results but smaller than anticipated based on comparison of alloy solubilities in sulfide melts and S-free silicate melts. The presence of S in the silicate melt greatly increases alloy solubility. We use our new set of partition coefficients to develop a fully constrained model of PGE behavior during melting which accurately predicts the abundances of PGE in mantle-derived magmas and their restites, including mid-ocean ridge basalts, continental picrites, and the parental magmas of the Bushveld Complex of South Africa. Our model constrains mid-ocean ridge basalt (MORB) to be the products of pooled low and high degree fractional melts. Within-plate picrites are pooled products of larger degrees of fractional melting in columnar melting regimes. A significant control on PGE fractionation in mantle-derived magmas is exerted by residual alloy or platinum group minerals in their source. At low pressures (e.g., MORB genesis) the mantle residual to partial melting retains primitive mantle inter-element ratios and abundances of PGE until sulfide has been completely dissolved but then evolves to extremely high Pt/Pd and low Pd/Ir because Pt and Ir alloys form in the restite. During melting at high pressure to form picrites or komatiites Ir alloy appears as a restite phase but Pt alloy is not stable due to the large effect of pressure on fS2, and of temperature on fO2 along an internal

  2. The mineralogy and mineral associations of platinum group elements and gold in the Platreef at Zwartfontein, Akanani Project, Northern Bushveld Complex, South Africa

    NASA Astrophysics Data System (ADS)

    van der Merwe, Frits; Viljoen, Fanus; Knoper, Mike

    2012-09-01

    The mineralogy of the platinum-group elements (PGE), and gold, in the Platreef of the Bushveld Complex, was investigated using an FEI Mineral Liberation Analyser. Polished sections were prepared from 171 samples collected from two boreholes, for the in-situ examination of platinum group minerals (PGM). PGM and gold minerals encountered include maslovite (PtBiTe, 32 area% of total PGM), kotulskite (Pd(BiTe), 17 %), isoferroplatinum (Pt3Fe, 15 %), sperrylite (PtAs2, 11 %), cooperite (PtS, 5 %), moncheite (PtTe2; 5 %), electrum (AuAg; 5 %), michenerite (PdBiTe; 3 %), Pd alloys (Pd, Sb, Sn; 3 %), hollingworthite ((Rh,Pt)AsS; 2 %), as well as minor (all <1 area% of total PGM) merenskyite (PdBiTe2), laurite (RuS2), rustenburgite (Pt0.4Pd0.4Sn0.2), froodite (PdBi2), atokite (Pd0.5Pt0.3Sn0.2), stumpflite (PtSb), plumbopalladinite (Pd3Pb2), and zvyagintsevite (Pd3Pb). An observed association of all PGM with base metal sulfides (BMS), and a pronounced association of PGE tellurides, arsenides and Pd&Pt alloys with secondary silicates, is consistent with the remobilisation and recrystallisation of some of the PGM's during hydrothermal alteration and serpentinisation subsequent to their initial (primary) crystallisation from BMS (e.g. Godel et al. J Petrol 48:1569-1604, 2007; Hutchinson and McDonald Appl Earth Sci (Trans Inst Min Metall B) 114:B208-224, 2008).

  3. Search for a meteoritic component in drill cores from the Bosumtwi impact structure, Ghana: Platinum group element contents and osmium isotopic characteristics

    NASA Astrophysics Data System (ADS)

    McDonald, Iain; Peucker-Ehrenbrink, Bernhard; Coney, Louise; Ferrière, Ludovic; Reimold, Wolf Uwe; Koeberl, Christian

    An attempt was made to detect a meteoritic component in both crater-fill (fallback) impact breccias and fallout suevites (outside the crater rim) at the Bosumtwi impact structure in Ghana. Thus far, the only clear indication for an extraterrestrial component related to this structure has been the discovery of a meteoritic signature in Ivory Coast tektites, which formed during the Bosumtwi impact event. Earlier work at Bosumtwi indicated unusually high levels of elements that are commonly used for the identification of meteoritic contamination (i.e., siderophile elements, including the platinum group elements [PGE]) in both target rocks and impact breccias from surface exposures around the crater structure, which does not allow unambiguous verification of an extraterrestrial signature. The present work, involving PGE abundance determinations and Os isotope measurements on drill core samples from inside and outside the crater rim, arrives at the same conclusion. Despite the potential of the Os isotope system to detect even small amounts of extraterrestrial contribution, the wide range in PGE concentrations and Os isotope composition observed in the target rocks makes the interpretation of unradiogenic, high-concentration samples as an impact signature ambiguous.

  4. Platinum-group element signatures in the North Atlantic Igneous Province: Implications for mantle controls on metal budgets during continental breakup

    NASA Astrophysics Data System (ADS)

    Hughes, Hannah S. R.; McDonald, Iain; Kerr, Andrew C.

    2015-09-01

    The North Atlantic Igneous Province (NAIP) is a large igneous province (LIP) that includes a series of lava suites erupted from the earliest manifestations of the (proto)-Icelandic plume, through continental rifting and ultimate ocean opening. The lavas of one of these sub-provinces, the British Palaeogene Igneous Province (BPIP), were some of the first lavas to be erupted in the NAIP and overlie a thick crustal basement and sedimentary succession with abundant S-rich mudrocks. We present the first platinum-group element (PGE) and Au analyses of BPIP flood basalts from the main lava fields of the Isle of Mull and Morvern and the Isle of Skye, in addition to a suite of shallow crustal dolerite volcanic plugs on Mull, and other minor lavas suites. BPIP lavas display both S-saturated and S-undersaturated trends which, coupled with elevated PGE abundances (> MORB), suggest that the BPIP is one of the most prospective areas of the NAIP to host Ni-Cu-PGE-(Au) mineralisation in conduit systems. Platinum-group element, Au and chalcophile element abundances in lavas from West and East Greenland, and Iceland, are directly comparable to BPIP lavas, but the relative abundances of Pt and Pd vary systematically between lavas suites of different ages. The oldest lavas (BPIP and West Greenland) have a broadly chondritic Pt/Pd ratio (~ 1.9). Lavas from East Greenland have a lower Pt/Pd ratio (~ 0.8) and the youngest lavas from Iceland have the lowest Pt/Pd ratio of the NAIP (~ 0.4). Hence, Pt/Pd ratio of otherwise equivalent flood basalt lavas varies temporally across the NAIP and appears to be coincident with the changing geodynamic environment of the (proto)-Icelandic plume through time. We assess the possible causes for such systematic Pt/Pd variation in light of mantle plume and lithospheric controls, and suggest that this reflects a change in the availability of lithospheric mantle Pt-rich sulphides for entrainment in ascending plume magmas. Hence the precious metal

  5. Increase in platinum group elements in Mexico City as revealed from growth rings of Taxodium mucronatum ten.

    PubMed

    Morton-Bermea, Ofelia; Beramendi-Orosco, Laura; Martínez-Reyes, Ángeles; Hernández-Álvarez, Elizabeth; González-Hernández, Galia

    2016-02-01

    Tree rings may be used as indicators of contamination events providing information on the chronology and the elemental composition of the contamination. In this framework, we report PGEs enrichment in growth rings of Taxodium mucronatum ten for trees growing in the central area of Mexico City as compared to trees growing in a non-urban environment. Concentrations of PGE were determined by ICP-MS analysis on microwave-digested tree rings. The element found in higher concentrations was Pd (1.13-87.98 μg kg(-1)), followed by Rh (0.28-36.81 μg kg(-1)) and Pt (0.106-7.21 μg kg(-1)). The concentration trends of PGEs in the tree-ring sequences from the urban area presented significant correlation values when comparing between trees (r between 0.618 and 0.98, P < 0.025) and between elements within individual trees (r between 0.76 and 0.994, P < 0.01). Furthermore, a clear increase was observed for rings after 1997, with enrichment of up to 60 times the mean concentration found for the sequence from the non-urban area and up to 40 times the mean concentration for the pre-1991 period in the urban trees. These results also demonstrate the feasibility of applying T. mucronatum ten to be used as a bioindicator of the increase in PGE in urban environments.

  6. Increase in platinum group elements in Mexico City as revealed from growth rings of Taxodium mucronatum ten.

    PubMed

    Morton-Bermea, Ofelia; Beramendi-Orosco, Laura; Martínez-Reyes, Ángeles; Hernández-Álvarez, Elizabeth; González-Hernández, Galia

    2016-02-01

    Tree rings may be used as indicators of contamination events providing information on the chronology and the elemental composition of the contamination. In this framework, we report PGEs enrichment in growth rings of Taxodium mucronatum ten for trees growing in the central area of Mexico City as compared to trees growing in a non-urban environment. Concentrations of PGE were determined by ICP-MS analysis on microwave-digested tree rings. The element found in higher concentrations was Pd (1.13-87.98 μg kg(-1)), followed by Rh (0.28-36.81 μg kg(-1)) and Pt (0.106-7.21 μg kg(-1)). The concentration trends of PGEs in the tree-ring sequences from the urban area presented significant correlation values when comparing between trees (r between 0.618 and 0.98, P < 0.025) and between elements within individual trees (r between 0.76 and 0.994, P < 0.01). Furthermore, a clear increase was observed for rings after 1997, with enrichment of up to 60 times the mean concentration found for the sequence from the non-urban area and up to 40 times the mean concentration for the pre-1991 period in the urban trees. These results also demonstrate the feasibility of applying T. mucronatum ten to be used as a bioindicator of the increase in PGE in urban environments. PMID:25903068

  7. Platinum-group element, Gold, Silver and Base Metal distribution in compositionally zoned sulfide droplets from the Medvezky Creek Mine, Noril'sk, Russia

    NASA Astrophysics Data System (ADS)

    Barnes, Sarah-Jane; Cox, R. A.; Zientek, M. L.

    2006-08-01

    Concentrations of Ag, Au, Cd, Co, Re, Zn and Platinum-group elements (PGE) have been determined in sulfide minerals from zoned sulfide droplets of the Noril’sk 1 Medvezky Creek Mine. The aims of the study were; to establish whether these elements are located in the major sulfide minerals (pentlandite, pyrrhotite, chalcopyrite and cubanite), to establish whether the elements show a preference for a particular sulfide mineral and to investigate the model, which suggests that the zonation in the droplets is caused by the crystal fractionation of monosulfide solid solution (mss). Nickel, Cu, Ag, Re, Os, Ir, Ru, Rh and Pd, were found to be largely located in the major sulfide minerals. In contrast, less than 25% of the Au, Cd, Pt and Zn in the rock was found to be present in these sulfides. Osmium, Ir, Ru, Rh and Re were found to be concentrated in pyrrhotite and pentlandite. Palladium and Co was found to be concentrated in pentlandite. Silver, Cd and Zn concentrations are highest in chalcopyrite and cubanite. Gold and platinum showed no preference for any of the major sulfide minerals. The enrichment of Os, Ir, Ru, Rh and Re in pyrrhotite and pentlandite (exsolution products of mss) and the low levels of these elements in the cubanite and chalcopyrite (exsolution products of intermediate solid solution, iss) support the mss crystal fractionation model, because Os, Ir, Ru, Rh and Re are compatible with mss. The enrichment of Ag, Cd and Zn in chalcopyrite and cubanite also supports the mss fractionation model these minerals are derived from the fractionated liquid and these elements are incompatible with mss and thus should be enriched in the fractionated liquid. Gold and Pt do not partition into either iss or mss and become sufficiently enriched in the final fractionated liquid to crystallize among the iss and mss grains as tellurides, bismithides and alloys. During pentlandite exsolution Pd appears to have diffused from the Cu-rich portion of the droplet into

  8. Experimental observations on noble metal nanonuggets and Fe-Ti oxides, and the transport of platinum group elements in silicate melts

    NASA Astrophysics Data System (ADS)

    Anenburg, Michael; Mavrogenes, John A.

    2016-11-01

    Platinum group element (PGE) nanonuggets are a nuisance in experimental studies designed to measure solubility or partitioning of noble metals in silicate melts. Instead of treating nanonuggets as experimental artifacts, we studied their behaviour motivated by recent discoveries of PGE nanonuggets in a variety of natural settings. We used an experimental setup consisting of AgPd, Pt or AuPd capsules and Fe(-Ti) oxide-saturated hydrous peralkaline silicate melts to maximise nanonugget production. TABS (Te, As, Bi, Sb, Sn) commonly occur in PGM (platinum group minerals), prompting addition of Bi to our experiments to investigate its properties as well. Three-dimensional optical examination by 100× objective and immersion oil reveals variable colour which correlates with nanonugget size and shape due to plasmon resonance effects. We observe two textural types: (1) intermediate-sized nanonuggets dispersed in the glass and adhering to oxides, and (2) abundant fine nanonuggets dispersed in the glass with coarse euhedral crystals in contact with oxides. Slow cooling removes dispersed nanonuggets and greatly coarsens existing oxide-associated metal crystals. Nanonugget-free halos are commonly observed around oxide grains. All metal phases are composed of major (Ag, Pd) and trace (Pt, Ir, Au) capsule material. Our results show reduction processes, imposed by growing oxides, causing local metal saturation in the oxide rich zones with preferential nucleation on smaller oxide grains. The redox gradient then blocks additional metals from diffusing into oxide rich zones, forming halos. As the entire experimental charge is reduced throughout the run, nanonuggets form in the distal glass. Bismuth contents of metal phases do not depend on Bi2O3 amounts dissolved in the melt. Further PGM crystallisation consumes nanonuggets as feedstock. We conclude that the appearance of metallic PGE phases happens in two stages: first as nanonuggets and then as larger PGM. Once formed

  9. Pt-Pd reefs in magnetitites of the Stella layered intrusion, South Africa: A world of new exploration opportunities for platinum group elements

    NASA Astrophysics Data System (ADS)

    Maier, W. D.; Barnes, S.-J.; Gartz, V.; Andrews, G.

    2003-10-01

    The 3033 Ma Stella layered intrusion of South Africa consists largely of magnetite gabbros and gabbros that are hosted by greenstones of the Kraaipan belt. The intrusion contains a 100-m-thick, platinum group element (PGE) enriched interval that includes a number of laterally continuous PGE reefs constituting the oldest mineralization of this type known on Earth. The richest of the reefs is hosted by magnetitite and contains 10 15 ppm Pt + Pd over 1 m, representing by far the highest PGE grades known up to this time in magnetitite-hosted Pt-Pd reefs. The PGEs are interpreted to have been concentrated by sulfide melt, after S saturation had been reached in the advanced stages of magmatic differentiation, in response to magnetite crystallization. Reaction between sulfide melt and oxides led to late magmatic S loss, causing a paucity of sulfides in most of the PGE mineralized interval. As a result, the reefs cannot be distinguished macroscopically from their unmineralized host rocks, and we suggest that similar mineralization may have been overlooked in the upper parts of other tholeiitic intrusions elsewhere.

  10. The pH-dependent release of platinum group elements (PGEs) from gasoline and diesel fuel catalysts: Implication for weathering in soils.

    PubMed

    Suchá, Veronika; Mihaljevič, Martin; Ettler, Vojtěch; Strnad, Ladislav

    2016-04-15

    Powdered samples of new and old gasoline catalysts (Pt, Pd, Rh) and new and old diesel (Pt) catalysts were subjected to a pH-static leaching procedure (pH 2-9) coupled with thermodynamic modeling using PHREEQC-3 to verify the release and mobility of PGEs (platinum group elements). PGEs were released under acidic conditions, mostly exhibiting L-shaped leaching patterns: diesel old: 5.47, 0.005, 0.02; diesel new: 68.5, 0.23, 0.11; gasoline old: 0.1, 11.8, 4.79; gasoline new 2.6, 25.2, 35.9 in mg kg(-1) for Pt, Pd and Rh, respectively. Only the new diesel catalyst had a strikingly different leaching pattern with elevated concentrations at pH 4, probably influenced by the dissolution of the catalyst carrier and washcoat. The pH-static experiment coupled with thermodynamic modeling was found to be an effective instrument for understanding the leaching behavior of PGEs under various environmental conditions, and indicated that charged Pt and Rh species may be adsorbed on the negatively charged surface of kaolinite or Mn oxides in the soil system, whereas uncharged Pd and Rh species may remain mobile in soil solutions.

  11. Determination of the platinum - Group elements (PGE) and gold (Au) in manganese nodule reference samples by nickel sulfide fire-assay and Te coprecipitation with ICP-MS

    USGS Publications Warehouse

    Balaram, V.; Mathur, R.; Banakar, V.K.; Hein, J.R.; Rao, C.R.M.; Gnaneswara, Rao T.; Dasaram, B.

    2006-01-01

    Platinum group elements (PGE) and Au data in polymetallic oceanic ferromanganese nodule reference samples and crust samples obtained by inductively coupled plasma mass spectrometry (ICP-MS), after separation and pre-concentration by nickel sulfide fire-assay and Te coprecipitation, are presented. By optimizing several critical parameters such as flux composition, matrix matching calibration, etc., best experimental conditions were established to develop a method suitable for routine analysis of manganese nodule samples for PGE and Au. Calibrations were performed using international PGE reference materials, WMG-1 and WMS-1. This improved procedure offers extremely low detection limits in the range of 0.004 to 0.016 ng/g. The results obtained in this study for the reference materials compare well with previously published data wherever available. New PGE data arc also provided on some international manganese nodule reference materials. The analytical methodology described here can be used for the routine analysis of manganese nodule and crust samples in marine geochemical studies.

  12. The pH-dependent release of platinum group elements (PGEs) from gasoline and diesel fuel catalysts: Implication for weathering in soils.

    PubMed

    Suchá, Veronika; Mihaljevič, Martin; Ettler, Vojtěch; Strnad, Ladislav

    2016-04-15

    Powdered samples of new and old gasoline catalysts (Pt, Pd, Rh) and new and old diesel (Pt) catalysts were subjected to a pH-static leaching procedure (pH 2-9) coupled with thermodynamic modeling using PHREEQC-3 to verify the release and mobility of PGEs (platinum group elements). PGEs were released under acidic conditions, mostly exhibiting L-shaped leaching patterns: diesel old: 5.47, 0.005, 0.02; diesel new: 68.5, 0.23, 0.11; gasoline old: 0.1, 11.8, 4.79; gasoline new 2.6, 25.2, 35.9 in mg kg(-1) for Pt, Pd and Rh, respectively. Only the new diesel catalyst had a strikingly different leaching pattern with elevated concentrations at pH 4, probably influenced by the dissolution of the catalyst carrier and washcoat. The pH-static experiment coupled with thermodynamic modeling was found to be an effective instrument for understanding the leaching behavior of PGEs under various environmental conditions, and indicated that charged Pt and Rh species may be adsorbed on the negatively charged surface of kaolinite or Mn oxides in the soil system, whereas uncharged Pd and Rh species may remain mobile in soil solutions. PMID:26874614

  13. Sulfide-scale insights into platinum-group element behavior during carbonate mantle metasomatism and evolution of Spitsbergen lithospheric mantle

    NASA Astrophysics Data System (ADS)

    Kim, Nak Kyu; Choi, Sung Hi; Dale, Christopher W.

    2016-03-01

    We report combined Re-Os isotope and highly siderophile element data for whole-rock and whole-sulfide grains from Spitsbergen peridotites. The Os-Ir contents in whole-rocks are elevated compared to those of the primitive mantle, but the Pt-Pd-Re contents are depleted, reflecting refractory monosulfide solid solution (Mss) control during mantle melting. There are two general types of sulfide documented in global mantle samples: primary residual Mss with subchondritic Pd/Ir ratios and secondary metasomatic sulfides with suprachondritic Pd/Ir ratios. Most Spitsbergen sulfides have elevated Ir contents, and belong to the residual group. Most but not all Spitsbergen sulfides, however, are unusual in that they show a fractionation of Os (and Ru) from Ir which cannot be reconciled with a simple partial melting process. The Os(+ Ru) fractionation from Ir is most notable in a sample containing mantle-derived carbonate-bearing pockets. Infiltration of carbonate-rich S-undersaturated melt into the Spitsbergen lithospheric mantle may result in the formation of localized S-rich liquid by dissolving residual Mss. Such melt compositions may promote laurite crystallization before Mss, causing the combined depletion of Os + Ru relative to Ir in later-formed Mss. The Re-depletion model ages of residual sulfide grains from Spitsbergen peridotites coincide with crustal ages determined for Spitsbergen, indicating coupled mantle-crust evolution, and furthermore, they coincide with the previously proposed major peaks of pulsed crustal formation periods in Earth at ca. 2.7, 1.9 and 1.2 Ga.

  14. Formation and geochemical significance of micrometallic aggregates including fissiogenic platinum group elements in the Oklo natural reactor, Gabon

    NASA Astrophysics Data System (ADS)

    Kikuchi, Makiko; Hidaka, Hiroshi; Gauthier-Lafaye, François

    2010-08-01

    Metallic aggregates with a size of a few tens μm and consisting mainly of Ru, Rh, Pd, Te, Pb, As, Sb, S and Bi were found in the acid residue of SD37-S2/CD uraninite taken from Oklo natural reactor zone (RZ) 13. Quantitative analyses of major elements using an electron probe microanalyzer and in situ isotopic analyses of Zr, Mo, Ru, Pb and U using a sensitive high-resolution ion microprobe were performed on the metallic aggregates to determine the geochemical behaviors of fission products and actinides and to ascertain the processes of formation of the aggregates in the RZs. The chemical compositions of the aggregates investigated in this study are significantly different from those reported previously, showing lower Pb content and no correlation between the contents of Pb and S in the individual grains. The 235U/ 238U ratios in metallic aggregates vary significantly from 0.00478 to 0.01466, indicating chemical fractionation between U and Pu during the formation of the aggregates. The Pb isotopic data indicate that most of the Pb in the aggregates decayed from 2.05 Ga-old uraninite that existed in the RZ originally and that there was chemical fractionation between U and Pb in some aggregates. The Zr and Mo isotopic ratios, 90Zr/ 91Zr and 95Mo/ 97Mo, for most of the aggregates had small variations, which can be simply explained by constant separate mixing of fissiogenic and nonfissiogenic components. On the other hand, a large variation in the 99Ru/ 101Ru ratio (0.324-1.73) cannot be explained only by a two component mixing theory; thus, chemical fractionation between Tc and Ru during the reactor criticality is suggested. The large variations in the 235U/ 238U and 99Ru/ 101Ru isotopic ratios suggest that the aggregates formed under various redox conditions owing to the radiolysis of water.

  15. Effects of mother lode-type gold mineralization on 187Os/188Os and platinum group element concentrations in peridotite: Alleghany District, California

    USGS Publications Warehouse

    Walker, R.J.; Böhlke, J.K.; McDonough, W.F.; Li, J.

    2007-01-01

    Osmium isotope compositions and concentrations of Re, platinum group elements (PGE), and Au were determined for host peridotites (serpentinites and barzburgites) and hydrothermally altered ultramafic wall rocks associated with Mother Lode-type hydrothermal gold-quartz vein mineralization in the Alleghany district, California. The host peridotites have Os isotope compositions and Re, PGE, and Au abundances typical of the upper mantle at their presumed formation age during the late Proterozoic or early Paleozoic. The hydrothermally altered rocks have highly variable initial Os isotope compositions with ??os, values (% deviation of 187OS/188OS from the chondritic average calculated for the approx. 120 Ma time of mineralization) ranging from -1.4 to -8.3. The lowest Os isotope compositions are consistent with Re depletion of a chondritic source (e.g., the upper mantle) at ca. 1.6 Ga. Most of the altered samples are enriched in Au and have depleted and fractionated abundances of Re and PGE relative to their precursor peridotites. Geoehemical characteristics of the altered samples suggest that Re and some PGE were variably removed from the ultramafic rocks during the mineralization event. In addition to Re, the Pt and Pd abundances of the most intensely altered rocks appear to have been most affected by mineralization. The 187Os-depleted isotopic compositions of some altered rocks are interpreted to be a result of preferential 187Os loss via destruction of Re-rich phases during the event. For these rocks, Os evidently is not a useful tracer of the mineralizing fluids. The results do, however, provide evidence for differential mobility of these elements, and mobility of 187Os relative to the initial bulk Os isotope composition during hydrothermal metasomatic alteration of ultramafic rocks. ?? 2007 Society of Economic Geologists, Inc.

  16. Petrology, geochemistry and the mechanisms determining the distribution of platinum-group element and base metal sulphide mineralisation in the Platreef at Overysel, northern Bushveld Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Holwell, David A.; McDonald, Iain

    2006-09-01

    Platinum-group element (PGE) mineralisation within the Platreef at Overysel is controlled by the presence of base metal sulphides (BMS). The floor rocks at Overysel are Archean basement gneisses, and unlike other localities along the strike of the Platreef where the floor is comprised of Transvaal Supergroup sediments, the intimate PGE-BMS relationship holds strong into the footwall rocks. Decoupling of PGE from BMS is rare and the BMS and platinum-group mineral assemblages in the Platreef and the footwall are almost identical. There is minimal overprinting by hydrothermal fluids; therefore, the mineralisation style present at Overysel may represent the most ‘primary’ style of Platreef mineralisation preserved anywhere along the strike. Chondrite-normalised PGE profiles reveal a progressive fractionation of the PGE with depth into the footwall, with Ir, Ru and Rh dramatically depleted with depth compared to Pt, Pd and Au. This feature is not observed at Sandsloot and Zwartfontein, to the south of Overysel, where the footwall rocks are carbonates. There is evidence from rare earth element abundances and the amount of interstitial quartz towards the base of the Platreef pyroxenites that contamination by a felsic melt derived from partial melting of the gneissic footwall has taken place. Textural evidence in the gneisses suggests that a sulphide liquid percolated down into the footwall through a permeable, inter-granular network that was produced by partial melting around grain boundaries in the gneisses that was induced by the intrusion of the Platreef magma. PGE were originally concentrated within a sulphide liquid in the Platreef magma, and the crystallisation of monosulphide solid solution from the sulphide liquid removed the majority of the IPGE and Rh from it whilst still within the mafic Platreef. Transport of PGE into the gneisses, via downward migration of the residual sulphide liquid, fractionated out the remaining IPGE and Rh in the upper parts of the

  17. Platinum-group element, Gold, Silver and Base Metal distribution in compositionally zoned sulfide droplets from the Medvezky Creek Mine, Noril'sk, Russia

    USGS Publications Warehouse

    Barnes, S.-J.; Cox, R.A.; Zientek, M.L.

    2006-01-01

    Concentrations of Ag, Au, Cd, Co, Re, Zn and Platinum-group elements (PGE) have been determined in sulfide minerals from zoned sulfide droplets of the Noril'sk 1 Medvezky Creek Mine. The aims of the study were; to establish whether these elements are located in the major sulfide minerals (pentlandite, pyrrhotite, chalcopyrite and cubanite), to establish whether the elements show a preference for a particular sulfide mineral and to investigate the model, which suggests that the zonation in the droplets is caused by the crystal fractionation of monosulfide solid solution (mss). Nickel, Cu, Ag, Re, Os, Ir, Ru, Rh and Pd, were found to be largely located in the major sulfide minerals. In contrast, less than 25% of the Au, Cd, Pt and Zn in the rock was found to be present in these sulfides. Osmium, Ir, Ru, Rh and Re were found to be concentrated in pyrrhotite and pentlandite. Palladium and Co was found to be concentrated in pentlandite. Silver, Cd and Zn concentrations are highest in chalcopyrite and cubanite. Gold and platinum showed no preference for any of the major sulfide minerals. The enrichment of Os, Ir, Ru, Rh and Re in pyrrhotite and pentlandite (exsolution products of mss) and the low levels of these elements in the cubanite and chalcopyrite (exsolution products of intermediate solid solution, iss) support the mss crystal fractionation model, because Os, Ir, Ru, Rh and Re are compatible with mss. The enrichment of Ag, Cd and Zn in chalcopyrite and cubanite also supports the mss fractionation model these minerals are derived from the fractionated liquid and these elements are incompatible with mss and thus should be enriched in the fractionated liquid. Gold and Pt do not partition into either iss or mss and become sufficiently enriched in the final fractionated liquid to crystallize among the iss and mss grains as tellurides, bismithides and alloys. During pentlandite exsolution Pd appears to have diffused from the Cu-rich portion of the droplet into

  18. Platinum-group element abundances and Re-Os isotopic systematics of the upper continental crust through time: Evidence from glacial diamictites

    NASA Astrophysics Data System (ADS)

    Chen, Kang; Walker, Richard J.; Rudnick, Roberta L.; Gao, Shan; Gaschnig, Richard M.; Puchtel, Igor S.; Tang, Ming; Hu, Zhao-Chu

    2016-10-01

    The fine-grained matrix of glacial diamictites, deposited periodically by continental ice sheets over much of Earth history, provides insights into the average composition and chemical evolution of the upper continental crust (UCC) (Gaschnig et al., 2016, and references therein). The concentrations of platinum-group elements (PGEs, including Os, Ir, Ru, Pt and Pd) and the geochemically related Re, as well as 187Re/188Os and 187Os/188Os ratios, are reported here for globally-distributed glacial diamictites that were deposited during the Mesoarchean, Paleoproterozoic, Neoproterozoic and Paleozoic eras. The medians and averages of PGE concentrations of these diamictite composites decrease from the Mesoarchean to the Neoproterozoic, mimicking decreases in the concentrations of first-row transition elements (Sc, V, Cr, Co and Ni). By contrast, Re concentrations are highly variable with no discernable trend, owing to its high solubility. Assuming these diamictites are representative of average UCC through time, the new data are fully consistent with the previous inference that the Archean UCC contained a greater proportion of mafic-ultramafic rocks relative to younger UCC. Linear regressions of PGEs versus Cr and Ni concentrations in all the diamictite composites from the four time periods are used to estimate the following concentrations of the PGEs in the present-day UCC: 0.059 ± 0.016 ng/g Os, 0.036 ± 0.008 ng/g Ir, 0.079 ± 0.026 ng/g Ru, 0.80 ± 0.22 ng/g Pt and 0.80 ± 0.26 ng/g Pd (2σ of 10,000 bootstrapping regression results). These PGE estimates are slightly higher than the estimates obtained from loess samples. We suggest this probably results from loess preferentially sampling younger UCC rocks that have lower PGE concentrations, or PGEs being fractionated during loess formation. A Re concentration of 0.25 ± 0.12 ng/g (2σ) is obtained from a regression of Re versus Mo. From this, time-integrated 187Re/188Os and 187Os/188Os ratios for the UCC are

  19. Platinum-group element geochemistry of the Hongge Fe-V-Ti deposit in the Pan-Xi area, southwestern China

    NASA Astrophysics Data System (ADS)

    Zhong, Hong; Zhou, Xin-Hua; Zhou, Mei-Fu; Sun, Min; Liu, Bing-Guang

    2002-03-01

    Mafic and ultramafic intrusions in the Pan-Xi area along the western margin of the Yangtze block, southwestern China, are spatially associated with the Late Permian Emeishan flood basalts of the Emeishan Large Igneous Province. The Hongge layered intrusion is one of the plutonic bodies of this province and hosts a giant Fe-V-Ti deposit. This intrusion has three zones: a lower, olivine clinopyroxenite zone, a middle, clinopyroxenite zone, and an upper, gabbro zone. Each of these zones consists of one or two compositional cycles, which have distinct Mg# values, TiO2 concentrations and total REE contents. The middle clinopyroxenite zone and upper gabbro zone contain thick (14-84 m) magnetite-mineralized layers. Samples from the lower olivine clinopyroxenite zone and middle clinopyroxenite zone of the Hongge intrusion are enriched in platinum and palladium relative to iridium and ruthenium. Rocks of the lower olivine clinopyroxenite zone have Pd/Ir ratios (1.8-22.3) lower than those of the middle clinopyroxenite zone (6.2 to 83 in its lower part and 3.6 to 49 in its upper part). The Pd/Ir ratios increase progressively upwards in each cyclic unit. Chromite is the major phase controlling concentrations of iridium and ruthenium. The Cu/Pd ratios at the bottom of each cyclic unit are close to that of the mantle and increase upwards. This variation suggests that each cyclic unit represents a new batch of magma, and sulfide mineral segregation removes PGE (platinum-group elements), Ni and Cu. Each cyclic unit in the Hongge layered intrusion might have resulted from crystal fractionation and mixing between a primary and evolved magma. The high Cu/Pd, Ti/Pd, Ni/Pd and Cu/Ir ratios of the intrusion suggest that the sulfide mineral segregation may have played an important role in PGE differentiation. If this interpretation is correct, then there is a potential to find economic PGE-rich horizon in the Hongge-type intrusions in the region.

  20. Platinum-group elements (PGE) and Rhenium in Marine Sediments across the Cretaceous-Tertiary Boundary: Constraints on Re-PGE Transport in the Marine Environment

    NASA Technical Reports Server (NTRS)

    Lee, Cin-Ty Aeolus; Wasserburg, Gerald J.; Kyte, Frank T.

    2003-01-01

    The nature of Re-platinum-group element (PGE; Pt, Pd, Ir, Os, Ru) transport in the marine environment was investigated by means of marine sediments at and across the Cretaceous-Tertiary boundary (KTB) at two hemipelagic sites in Europe and two pelagic sites in the North and South Pacific. A traverse across the KTB in the South Pacific pelagic clay core found elevated levels of Re, Pt, Ir, Os, and Ru, each of which is approximately symmetrically distributed over a distance of approx. 1.8 m across the KTB. The Re-PGE abundance patterns are fractionated from chondritic relative abundances: Ru, Pt, Pd, and Re contents are slightly subchondritic relative to Ir, and Os is depleted by approx. 95% relative to chondritic Ir proportions. A similar depletion in Os (approx. 90%) was found in a sample of the pelagic KTB in the North Pacific, but it is enriched in Ru, Pt, Pd, and Re relative to Ir. The two hemipelagic KTB clays have near-chondritic abundance patterns. The approx. 1.8-m-wide Re-PGE peak in the pelagic South Pacific section cannot be reconciled with the fallout of a single impactor, indicating that postdepositional redistribution has occurred. The elemental profiles appear to fit diffusion profiles, although bioturbation could have also played a role. If diffusion had occurred over approx. 65 Ma, the effective diffusivities are approx. 10(exp -13)sq cm/s, much smaller than that of soluble cations in pore waters (approx. 10(exp -5) sq cm/s). The coupling of Re and the PGEs during redistribution indicates that postdepositional processes did not significantly fractionate their relative abundances. If redistribution was caused by diffusion, then the effective diffusivities are the same. Fractionation of Os from Ir during the KTB interval must therefore have occurred during aqueous transport in the marine environment. Distinctly subchondritic Os/Ir ratios throughout the Cenozoic in the South Pacific core further suggest that fractionation of Os from Ir in the marine

  1. Abundances of platinum group elements in native sulfur condensates from the Niuatahi-Motutahi submarine volcano, Tonga rear arc: Implications for PGE mineralization in porphyry deposits

    NASA Astrophysics Data System (ADS)

    Park, Jung-Woo; Campbell, Ian H.; Kim, Jonguk

    2016-02-01

    Some porphyry Cu-Au deposits, which are enriched in Pd, are potentially an economic source of Pd. Magmatic volatile phases are thought to transport the platinum group elements (PGEs) from the porphyry source magma to the point of deposition. However, the compatibilities of the PGEs in magmatic volatile phases are poorly constrained. We report PGE and Re contents in native sulfur condensates and associated altered dacites from the Niuatahi-Motutahi submarine volcano, Tonga rear arc, in order to determine the compatibility of PGEs and Re in magmatic volatile phases, and their mobility during secondary hydrothermal alteration. The native sulfur we analyzed is the condensate of a magmatic volatile phase exsolved from the Niuatahi-Motutahi magma. The PGEs are moderately enriched in the sulfur condensates in comparison to the associated fresh dacite, with enrichment factors of 11-285, whereas Au, Cu and Re are strongly enriched with enrichment factors of ∼20,000, ∼5000 and ∼800 respectively. Although the PGEs are moderately compatible into magmatic volatile phases, their compatibility is significantly lower than that of Au, Cu and Re. Furthermore, the compatibility of PGEs decrease in the order: Ru > Pt > Ir > Pd. This trend is also observed in condensates and sublimates from other localities. PGE mineralization in porphyry Cu-Au deposits is characterized by substantially higher Pd/Pt (∼7-60) and Pd/Ir (∼100-10,500) than typical orthomagmatic sulfide deposits (e.g. Pd/Pt ∼0.6 and Pd/Ir ∼20 for the Bushveld). It has previously been suggested that the high mobility of Pd, relative to the other PGEs, may account for the preferential enrichment of Pd in porphyry Cu-Au deposits. However, the low compatibility of Pd in the volatile phase relative to the other PGEs, shown in this study, invalidates this explanation. We suggest that the PGE geochemistry of Pd-rich Cu-Au deposits is principally derived from the PGE characteristics of the magma from which the ore

  2. Levels and risk assessment for humans and ecosystems of platinum-group elements in the airborne particles and road dust of some European cities.

    PubMed

    Gómez, B; Palacios, M A; Gómez, M; Sanchez, J L; Morrison, G; Rauch, S; McLeod, C; Ma, R; Caroli, S; Alimonti, A; Petrucci, E; Bocca, B; Schramel, P; Zischka, M; Petterson, C; Wass, U

    2002-11-01

    Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3-13.1 pg m(-3). The ring roads of these cities have values in the range 4.1-17.7 pg m(-3). In Munich, a lower Pt content was found in airborne particles (4.1 pg m(-3)). The same tendency has been noted for downtown Rh, with contents in the range 2.2-2.8 pg m(-3), and in the range 0.8-3.0 and 0.3 pg m(-3) for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles

  3. Comparison of synthetic fluid inclusion and quartz-trap methods for determining platinum- group element (PGE) solubility in hydrous salt melts at magmatic conditions

    NASA Astrophysics Data System (ADS)

    Hanley, J. J.

    2007-12-01

    Layered intrusions preserve magmatic inclusions containing hydrous halide melt phases composed of transition metal chlorides with less than 5 wt% H2O. Previous attempts at measuring platinum-group element (PGE) solubility in such high salinity volatiles through the analysis of synthetic fluid inclusions have shown that, although the PGE appear to be highly soluble at geologically-realistic conditions, it is difficult to determine if trapped fluids represent equilibrium fluid compositions. Wide ranges in trapped metal content may result from (i) premature formation of fluid inclusions owing to rapid rates of silicate mineral healing (i.e., hours at magmatic conditions in a saline fluid), (ii) premature entrapment of fluids in which the approach to equilibrium metal solubility requires the generation of the metal-complexing ligands (e.g., HCl) from a slow fluid-mineral or fluid- melt buffer reaction, (iii) the dissolution and reprecipitation of PGE in opened inclusions due to subtle temperature or chemical gradients in run capsules, or (iv) heterogeneous fluid compositions due to the presence of PGE micronuggets or colloids that are more abundant near metal-fluid or metal-buffer interfaces. To circumvent some of the problems associated with synthetic inclusion methods, the solubility of platinum in a hydrous salt melt (S-free; 75 wt% CaCl2+MgCl2, 25 wt% H2O) was investigated at elevated T (700°C) and low crustal pressure. The salt melts were reacted with PtAs2 (natural sperrylite) in Pt capsules buffered at an oxygen fugacity of FMQ-1 using a mixed gas buffer and by the solid mineral assemblage tremolite- diopside-enstatite-quartz which fixes the concentration of relevant metal-complexing ligands at run conditions. Salt melts were trapped (simultaneously) in the matrix of a quartz trap (granulated natural quartz partially isolated in a smaller gold capsule) and in synthetic melt inclusions trapped in pre-fractured quartz. After quenching, the melt inclusions and

  4. Ages and sources of components of Zn-Pb, Cu, precious metal, and platinum group element deposits in the goodsprings district, clark county, Nevada

    USGS Publications Warehouse

    Vikre, P.; Browne, Q.J.; Fleck, R.; Hofstra, A.; Wooden, J.

    2011-01-01

    The Goodsprings district, Clark County, Nevada, includes zinc-dominant carbonate replacement deposits of probable late Paleozoic age, and lead-dominant carbonate replacement deposits, copper ?? precious metal-platinum group element (PGE) deposits, and gold ?? silver deposits that are spatially associated with Late Triassic porphyritic intrusions. The district encompasses ??500 km2 although the distribution of all deposits has been laterally condensed by late Mesozoic crustal contraction. Zinc, Pb, and Cu production from about 90 deposits was ??160,000 metric tons (t) (Zn > Pb >> Cu), 2.1 million ounces (Moz) Ag, 0.09 Moz Au, and small amounts of PGEs-Co, V, Hg, Sb, Ni, Mo, Mn, Ir, and U-were also recovered. Zinc-dominant carbonate replacement deposits (Zn > Pb; Ag ?? Cu) resemble Mississippi Valley Type (MVT) Zn-Pb deposits in that they occur in karst and fault breccias in Mississippian limestone where the southern margin of the regional late Paleozoic foreland basin adjoins Proterozoic crystalline rocks of the craton. They consist of calcite, dolomite, sphalerite, and galena with variably positive S isotope compositions (??34S values range from 2.5-13%), and highly radiogenic Pb isotope compositions (206Pb/204Pb >19), typical of MVT deposits above crystalline Precambrian basement. These deposits may have formed when southward flow of saline fluids, derived from basinal and older sedimentary rocks, encountered thinner strata and pinch-outs against the craton, forcing fluid mixing and mineral precipitation in karst and fault breccias. Lead-dominant carbonate replacement deposits (Pb > Zn, Ag ?? Cu ?? Au) occur among other deposit types, often near porphyritic intrusions. They generally contain higher concentrations of precious metals than zinc-dominant deposits and relatively abundant iron oxides after pyrite. They share characteristics with copper ?? precious metal- PGE and gold ?? silver deposits including fine-grained quartz replacement of carbonate minerals in

  5. The use of cation exchange matrix separation coupled with ICP-MS to directly determine platinum group element (PGE) and other trace element emissions from passenger cars equipped with diesel particulate filters (DPF).

    PubMed

    Cairns, Warren R L; De Boni, Antonella; Cozzi, Giulio; Asti, Massimo; Borla, Edoardo Merlone; Parussa, Flavio; Moretto, Ezio; Cescon, Paolo; Boutron, Claude; Gabrieli, Jacopo; Barbante, Carlo

    2011-03-01

    Inductively coupled plasma-mass spectrometry coupled with cation exchange matrix separation has been optimised for the direct determination of platinum group element (PGE) and trace element emissions from a diesel engine car. After matrix separation method detection limits of 1.6 ng g(-1) for Pd, 0.4 ng g(-1) for Rh and 4.3 ng g(-1) for Pt were achieved, the method was validated against the certified reference material BCR 723, urban road dust. The test vehicle was fitted with new and aged catalytic converters with and without diesel particulate filters (DPF). Samples were collected after three consecutive New European Driving Cycle (NEDC) of the particulate and "soluble" phases using a home-made sampler optimised for trace element analysis. Emission factors for the PGEs ranged from 0.021 ng km(-1) for Rh to 70.5 ng km(-1) for Pt; when a DPF was fitted, the emission factors for the PGEs actually used in the catalysts dropped by up to 97% (for Pt). Trace element emission factors were found to drop by a maximum of 92% for Ni to a minimum of 18% for Y when a DPF was fitted; a new DPF was also found to cause a reduction of up to 86% in the emission of particulate matter.

  6. Multiple magma evolution and ore-forming processes of the Hongge layered intrusion, SW China: Insights from Sr-Nd isotopes, trace elements and platinum-group elements

    NASA Astrophysics Data System (ADS)

    Liao, Mingyang; Tao, Yan; Song, Xieyan; Li, Yubang; Xiong, Feng

    2015-12-01

    The Hongge layered intrusion (259 Ma), which is located in the inner zone of the Emeishan large igneous province (ELIP), is one of the most typical Fe-Ti-V ore deposits in the Pan-Xi area. Mafic-ultramafic layered intrusions of the ELIP have attracted a lot of attention lately because these intrusions host world class Fe-Ti-V oxide deposits plus interesting Cu-Ni-(PGE) mineralization which may have economic potential. This paper, reports new whole-rock major and trace element compositions, PGE abundances and Sr-Nd isotopic data for selected cumulate rocks and basalts. We use these data to investigate the nature of parental magmas and the controls on its evolution from the source mantle en route to the surface involving the Hongge ore-bearing intrusion. Two abrupt changes in Mt/Ilm and trace element ratios such as Ba/Th with depths in the Hongge layered intrusion indicate that this intrusion formed by at least two pluses of relatively primitive magma. The whole rock Sr-Nd isotopic data of basaltic and intrusive rocks plot in the region of Emeishan low-Ti basalts and the compositions of residual liquid (at ∼1260 °C and 1155 °C) calculated by MELTS are similar to our actual high-Ti (BFQ-2) and low-Ti (BC-1) basltic samples, indicate they are co-magmatic rather than derivation from a distinct source. Total PGE abundances in the Hongge samples are extremely low, ranging from 0.5 to 10 ppb. Sulfide-bearing rocks in the Hongge intrusion and the nearby coeval Banfangqing and Baicao basalts have similar mantle-like Pd/Pt ratios (2-6) and extremely high Cu/Pd ratios (3 × 104 to 4 × 105), indicating that sulfide segregation took place at depth prior to emplacement at Hongge and eruption in this region. Sulfide saturation in the Hongge magma may have resulted from such crustal contamination event. Crystallization of silicate minerals under the anhydrous magma, magma hydration plus Fe-Ti enrichments in the parental magma are three critical factors for the formation of Fe

  7. Platinum group nuggets in deep sea sediments

    NASA Technical Reports Server (NTRS)

    Brownlee, D. E.; Bates, B. A.; Wheelock, M. M.

    1984-01-01

    The existence of iron meteor oblation spheres in deep sea sediments was known for over a century. These spheres generally were believed to be composed of either pure magnetite and wustite or an oxide shell surrounding a NiFe metal core. A large number of 300 micron to 600 micron spheres found were pure oxide spheres, usually containing a solitary 10 micron platinum group nugget (pgn) composed almost entirely of group VIII metals. Twelve PGN's were analyzed and most had chondritic abundances with some depletions that correlate with element volatility. PGN formation by oxidation of a molten metal sphere entering the atmosphere cannot occur if the oxygen abundance in the atmosphere is less than half of its present value. The first appearance of PGN's in the geological record should mark when, in the Earth's history, oxygen rose to this level.

  8. Concentration of some platinum-group metals in coal

    USGS Publications Warehouse

    Finkelman, R.B.; Aruscavage, P. J.

    1981-01-01

    New data on some platinum group metals in coal indicate that the concentration of Pt is generally less than about 5 ppb, that of Pd is generally less than 1 ppb, and that of Rh is generally less than 0.5 ppb. No conclusive evidence was obtained concerning the mode of occurrence of these elements in coal. ?? 1981.

  9. Mineral resource of the month: platinum-group metals

    USGS Publications Warehouse

    Hilliard, Henry

    2003-01-01

    The precious metals commonly referred to as platinum-group metals (PGM) include iridium, osmium, palladium, platinum, rhodium and ruthenium. PGM are among the rarest of elements, and their market values — particularly for palladium, platinum and rhodium — are the highest of all precious metals.

  10. Extraterrestrial platinum group nuggets in deep-sea sediments

    NASA Technical Reports Server (NTRS)

    Brownlee, D. E.; Bates, B. A.; Wheelock, M. M.

    1984-01-01

    A previously unrecognized property of iron cosmic spheres is reported. The most common spheres larger than 300 microns do not, in fact, contain FeNi metal cores, but instead contain a micrometer-sized nugget composed almost entirely of platinum group elements. These elements appear to have been concentrated by the oxidation of molten meteoritic metal during atmospheric entry. This process is critically dependent on the relative abundance of oxygen in the atmosphere, and the first appearance of the nuggets in the geological record may provide a marker indicating when the oxygen abundance attained half of its present level.

  11. Exhaust system having a gold-platinum group metal catalyst

    DOEpatents

    Ragle, Christie Susan; Silver, Ronald G.; Zemskova, Svetlana Mikhailovna; Eckstein, Colleen J.

    2012-08-07

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  12. Exhaust system having a gold-platinum group metal catalyst

    DOEpatents

    Ragle, Christie Susan; Silver, Ronald G.; Zemskova, Svetlana Mikhailovna; Eckstein, Colleen J.

    2011-12-06

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  13. Contamination from gold and platinum-group metals mining in the Gulf of Darién, Colombia

    NASA Astrophysics Data System (ADS)

    Vasquez-Bedoya, L.; Palacio Baena, J.

    2013-12-01

    Gulf of Darién, triangular southernmost extension of the Caribbean Sea, bounded by Panama on the southwest and by Colombia on the southeast and east. The Gulf is made up of 17 municipalities in the department of Choco and Antioquia. The Gulf of Darién is a geostrategic region, rich in biodiversity, known for its natural resources of minerals, oil, lumber as well as its water and fertile land. The Darién also acts as the bridge between South America and Central America and has access to the Pacific Ocean and the Caribbean Sea. The economy in the region is based mainly on agribusinesses, tourism and mining activities, mainly the 'mining of gold and platinum-group metals'. In our study we determined the degree of trace element contamination in estuarine sediment samples originated from mining activities and municipal waste water discharges of effluents on the gulf of Darién. . Surface samples were taken from 17 locations through the entire Gulf. Grain size, Corg, Ag, Al, Ca , Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb and Zn concentrations were analyzed, and enrichment factors (EF) as well as geo-accumulation indices (Igeo) were calculated. Concentrations of Pb, Zn, Ni, Cu and Cr show levels that are consistent with those typically found in urbanized marine environments. EF and Igeo values revealed that the Gulf is extremely contaminated with Ag and moderately contaminated with Cr and Zn. The sources of Cr, Ag, Hg and Zn are associated with the development of mining activities in the Atrato River basin. The observed enrichment of Ag may be explained as a residue of the extraction of gold and platinum-group metals.

  14. Partitioning of platinum-group elements (PGE) and chalcogens (Se, Te, As, Sb, Bi) between monosulfide-solid solution (MSS), intermediate solid solution (ISS) and sulfide liquid at controlled fO2-fS2 conditions

    NASA Astrophysics Data System (ADS)

    Liu, Yanan; Brenan, James

    2015-06-01

    In order to better understand the behavior of highly siderophile elements (HSEs: Os, Ir, Ru, Rh, Pt, Pd, Au, Re), Ag, Pb and chalcogens (As, Se, Sb, Te and Bi) during the solidification of sulfide magmas, we have conducted a series of experiments to measure partition coefficients (D values) between monosulfide solid solution (MSS) and sulfide melt, as well as MSS and intermediate solid solution (ISS), at 0.1 MPa and 860-926 °C, log fS2 -3.0 to -2.2 (similar to the Pt-PtS buffer), with fO2 controlled at the fayalite-magnetite-quartz (FMQ) buffer. The IPGEs (Os, Ir, Ru), Rh and Re are found to be compatible in MSS relative to sulfide melt with D values ranging from ∼20 to ∼5, and DRe/DOs of ∼0.5. Pd, Pt, Au, Ag, Pb, as well as the chalcogens, are incompatible in MSS, with D values ranging from ∼0.1 to ∼1 × 10-3. For the same metal/sulfur ratio, D values for the IPGEs, Rh and Re are systematically larger than most past studies, correlating with higher oxygen content in the sulfide liquid, reflecting the significant effect of oxygen on increasing the activity coefficients for these elements in the melt phase. MSS/ISS partitioning experiments reveal that Ru, Os, Ir, Rh and Re are partitioned into MSS by a factor of >50, whereas Pd, Pt, Ag, Au and the chalcogens partition from weakly (Se, As) to strongly (Ag, Au) into ISS. Uniformly low MSS- and ISS- melt partition coefficients for the chalcogens, Pt, Pd, Ag and Au will lead to enrichment in the residual sulfide liquid, but D values are generally too large to reach early saturation in Pt-Pd-chalcogen-rich accessory minerals, based on current solubility estimates. Instead, these phases likely precipitate at the last dregs of crystallization. Modeled evolution curves for the PGEs and chalcogens are in reasonably good agreement with whole-rock sulfide compositions for the McCreedy East deposit (Sudbury, Ontario), consistent with an origin by crystallization of MSS, then MSS + ISS from sulfide magma.

  15. Occurrence model for magmatic sulfide-rich nickel-copper-(platinum-group element) deposits related to mafic and ultramafic dike-sill complexes: Chapter I in Mineral deposit models for resource assessment

    USGS Publications Warehouse

    Schulz, Klaus J.; Woodruff, Laurel G.; Nicholson, Suzanne W.; Seal, Robert R., II; Piatak, Nadine M.; Chandler, Val W.; Mars, John L.

    2014-01-01

    The sulfides in magmatic Ni-Cu deposits generally constitute a small volume of the host rock(s) and tend to be concentrated in the lower parts of the mafic and/or ultramafic bodies, often in physical depressions or areas marking changes in the geometry of the footwall topography. In most deposits, the sulfide mineralization can be divided into disseminated, matrix or net, and massive sulfide, depending on a combination of the sulfide content of the rock and the silicate texture. The major Ni-Cu sulfide mineralogy typically consists of an intergrowth of pyrrhotite (Fe7S8), pentlandite ([Fe, Ni]9S8), and chalcopyrite (FeCuS2). Cobalt, PGE, and gold (Au) are extracted from most magmatic Ni-Cu ores as byproducts, although such elements can have a significant impact on the economics in some deposits, such as the Noril’sk-Talnakh deposits, which produce much of the world’s palladium. In addition, deposits may contain between 1 and 15 percent magnetite associated with the sulfides.

  16. Elemental accumulation studied in biological species

    SciTech Connect

    Not Available

    1986-01-01

    At The Geysers, relatively little environmental baseline data were collected during the early years of development. In early 1983, the CEC awarded Sonoma County a geothermal grant to analyze the biological accumulation of trace elements in The Geysers Geothermal region. Prior studies in The Geysers region have established data for 27 different chemical elements, and suggest that chemicals are accumulating near power plants. This study examined selected species of rodents, fish, and lichen. Elevated amounts of chemical elements were found in their tissues. It is not clear if this accumulation is the result of geothermal development or due to naturally high backgrounds of these elements in the region. However, today these element loads serve as reference points for both developers and regulators. The CEC awarded a second grant in July 1985. The study funded by this grant will provide a more complete analysis of elemental loads by examining species such as western fence lizards and deer. Results and conclusions from these two studies can be used by regulatory agencies planning for future geothermal development in The Geysers region.

  17. Chalcophile and platinum-group element distribution in the Ultramafic series of the Stillwater Complex, MT, USA—implications for processes enriching chromite layers in Os, Ir, Ru, and Rh

    NASA Astrophysics Data System (ADS)

    Barnes, Sarah-Jane; Pagé, P.; Prichard, H. M.; Zientek, M. L.; Fisher, P. C.

    2016-01-01

    All of the rocks from the Ultramafic series of the Stillwater Complex are enriched in PGE relative to most mafic magmas. Furthermore, the chromite layers are particularly enriched in IPGE (Os, Ir, and Ru) and Rh. This enrichment appears to be a common characteristic of ultramafic rocks from many types of settings, layered intrusions, ophiolites, and zoned complexes. We have carried out a petrological, mineralogical, and geochemical study to assess how the enrichment occurred in the case of the Stillwater Complex and applied our results to the chromite layers of the Bushveld and Great Dyke complexes. The minerals that now host the PGE are laurite and fine-grained intergrowths of pentlandite, millerite, and chalcopyrite. The laurite occurs as inclusions in chromite, and mass balance calculations indicate that it hosts most of the Os, Ir, and Ru. The sulfide minerals occur both as inclusions in chromite and as interstitial grains. The sulfides host much of the Pd and Rh. The IPGE and Rh correlate with Cr but not with S or Se, indicating that these elements were not collected by a sulfide liquid. Palladium, Cu, and Se correlate with each other, but not with S. The low S/Se (<1500) of the whole rock and magnetite rims around the sulfides indicate some S has been lost from the rocks. We conclude that to account for all observations, the IPGE and Rh were originally collected by chromite, and subsequently, small quantities of base metal sulfide liquid was added to the chromite layers from the overlying magma. The IPGE and Rh in the chromite diffused from the chromite into the base metal sulfides and converted some of the sulfides to laurite.

  18. International strategic minerals inventory summary report: platinum-group metals

    USGS Publications Warehouse

    Sutphin, David M.; Page, Norman J

    1986-01-01

    Major world resources of platinum-group metals are described in this summary report of information in the International Strategic Minerals Inventory {ISMI}. ISMI is a cooperative data-collection effort of earth-science and mineral-resource agencies in Australia, Canada, the Federal Republic of Germany, the Republic of South Africa, and the United States of America. This report, designed to be of benefit to policy analysts, contains two parts. Part I presents an overview of the resources and potential supply of platinum-group metals on the basis of inventory information. Part II contains tables of some of the geologic information and mineral-resource and production data that were collected by ISMI participants.

  19. Mineral resource of the month: platinum group metals

    USGS Publications Warehouse

    Loferski, Patricia J.

    2010-01-01

    The article focuses on platinum group metals (PGMs) and their properties. According to the author, PGMs, which include iridium, osmium, palladium, platinum, rhodium, and ruthenium, are among the rarest mineral commodities in the Earth's crust. PGMs are primarily used as catalytic converters that clean harmful exhaust from vehicle engines. They are also used in the chemical industry as catalysts in the production of nitric acid and in the petroleum refining industry.

  20. Photochemistry and charge transfer chemistry of the platinum group elements

    SciTech Connect

    Eisenberg, R.

    1992-12-01

    During the past 3 years, progress was made in elucidating the excited state structures of Pt(diimine)(dithiolate) complexes, while more recent efforts focused on the photochemistry of these complexes and electronic structure of other dithiolate systems. A carbonyl-Ir-maleonitrile dithiolate complex is also studied.

  1. Separation of platinum group metal ions by Donnan dialysis

    SciTech Connect

    Brajter, K.; Slonawska, K.; Cox, J.A.

    1985-10-01

    Separations of metal ions on the basis of Donnan dialysis across anion-exchange membranes should be possible if the receiver electrolyte composition favors the formation of selected anionic complexes of the sample metal ions. Moreover, such a separation has the possibility of being better suited from some applications than batch or column experiments with anion-exchange resins. The above hypothesis are tested on the platinum-group metal ions, Pt(IV), Rh(III), Pd(II), Ir(III), and Ir(IV). 13 references, 4 tables.

  2. Recent strikes in South Africa’s platinum-group metal mines: effects upon world platinum-group metal supplies

    USGS Publications Warehouse

    Yager, Thomas R.; Soto-Viruet, Yadira; Barry, James J.

    2012-01-01

    The recent labor disputes over wages and working conditions that have affected South Africa’s three leading platinum-group metal (PGM) producers have affected an industry already plagued by market pressures and labor unrest and raised the specter of constraints in the world’s supply of these metals. Although low demand for these metals in 2011 and 2012 helped to offset production losses of recent years, and particularly those losses caused by the strikes in 2012, a prolonged resumption of strikes could cause severe shortages of iridium, platinum, rhodium, ruthenium, and, to a lesser extent, palladium.

  3. Platinum group minerals (PGM) in the Falcondo Ni-laterite deposit, Loma Caribe peridotite (Dominican Republic)

    NASA Astrophysics Data System (ADS)

    Aiglsperger, Thomas; Proenza, Joaquin A.; Zaccarini, Federica; Lewis, John F.; Garuti, Giorgio; Labrador, Manuel; Longo, Francisco

    2015-01-01

    Two Ni-laterite profiles from the Loma Caribe peridotite (Dominican Republic) have been investigated for their platinum group element (PGE) geochemistry and mineralogy. One profile (Loma Peguera) is characterized by PGE-enriched (up to 3.5 ppm total PGE) chromitite bodies incorporated within the saprolite, whereas the second profile is chromitite-free (Loma Caribe). Total PGE contents of both profiles slightly increase from parent rocks (36 and 30 ppb, respectively) to saprolite (˜50 ppb) and reach highest levels within the limonite zone (640 and 264 ppb, respectively). Chondrite-normalized PGE patterns of saprolite and limonite reveal rather flat shapes with positive peaks of Ru and Pd. Three types of platinum group minerals (PGM) were found by using an innovative hydroseparation technique: (i) primary PGM inclusions in fresh Cr-spinel (laurite and bowieite), (ii) secondary PGM (e.g., Ru-Fe-Os-Ir compounds) from weathering of preexisting PGM (e.g., serpentinization and/or laterization), and (iii) PGM precipitated after PGE mobilization within the laterite (neoformation). Our results provide evidence that (i) PGM occurrence and PGE enrichment in the laterite profiles is independent of chromitite incorporation; (ii) PGE enrichment is residual on the profile scale; and (iii) PGE are mobile on a local scale leading to in situ growth of PGM within limonite, probably by bioreduction and/or electrochemical metal accretion.

  4. Donnan dialysis of bromocomplexes of some platinum group metal ions

    SciTech Connect

    Brajter, K.; Slonawska, K. ); Cox, J.A. )

    1989-03-01

    The separation of bromocomplexes of platinum group metals by Donnan dialysis is demonstrated with both anion and cation exchange membranes. The inclusion of ethylenediamine (en) in the sample improves the separation of Pd(II) from Pt(IV) with experiments performed with an anion exchange membrane and decreases the amount of metal retained on the membrane phase. With a cation exchange membrane, the addition of a ligand such as en is required for transport. With 5.6 mM en in the sample at pH 10, 74% of Pd(II) is transported across an anion exchange membrane into 0.5 M NH{sub 4} Br after 6 hours while only 8% of the Pt(IV) is dialyzed. Rhodium(III) and iridium(III) behave like Pt(IV). Using a cation exchange membrane under the same conditions except with a 1 hour dialysis results in a 30-fold preferential preconcentration of Pd(II) relative to Pt(IV), and, based on the amount retained in the membrane, a preconcentration of Ir(III) which exceeds that of Pd(II) and Pt(IV) by factors of 40 and 20, respectively.

  5. The Bioaccumulation and Toxicity of Platinum Group Metals in Developing Chick Embryos

    NASA Astrophysics Data System (ADS)

    Pavel, Ioana; Monahan, Jennifer; Markopoulos, Marjorie; Gagnon, Zofia; Nejame, Britney; Cawley, Jacob; Reens, David

    2008-10-01

    Recent studies showed that platinum group metals (PGMs) such as Pt, Pd, and Rh from automobile catalytic converters, can accumulate in the soft tissues of a variety of living organisms. However, the effects of PGMs on bone and organs development of animals are not clearly understood. To examine these aspects, developing chick embryos were injected with 0.1, 1.0, 5, or 10 ppm solutions of Pt, Rh, Pd, or with a PGMs mixture. 1) Pathological Changes: were observed for all PGM treatments above 1 ppm. Bone Cells Assesment: Chondrocyte cells in thibiotarsus showed decreased diameter and length. 2) PGMs Accumulation in Tissues: was quantified by GFAAS spectrometry on finely ground tissue powder. 3) Bone Demineralization: was detected by micro-Raman spectroscopy imaging on paraffin embedded bone sections. 4) DNA Damage in Cells: was determined by using a Comet assay and fluorescence spectroscopy. Oxidative Damage in Tissues: was analyzed using a glutathione peroxidase assay. The overall results indicated that PGMs presence in our environment raises concerns about their long-term health effects on all organisms.

  6. First determination of the levels of platinum group metals in Manta birostris (manta ray) caught along the Ghanaian coastline.

    PubMed

    Essumang, D K

    2010-06-01

    Tissues from Manta birostris caught by fishermen from Dixcove in the western part of Ghana were analyzed for their Platinum, palladium and rhodium concentrations (PGM). The use of chondrichthyan fish has permitted the study of trace levels of Platinum group metals (PGMs) which have travelled very far into the sea. The analysis showed that Ghana's coastline is fairly polluted with these platinum group metals (PGMs). PGM concentration in manta ray recorded a range of (0.15-0.85) microg/g for Pt, (0.033-0.67) microg/g for Pd and (0.007-0.145) microg/g for Rh. Comparing these values to the UK dietary intake of 0.2 microg/day for Pt and Rh and 1.0 microg/day for Pd, its indicates that the values obtained from the analysis for Pt was above the required level. This is the first study to show the accumulation of PGM in chondrichthyan fish, although the sources of this pollution are not clear as manta birostris is migratory and therefore need to be investigated further. The presence of the PGM is very significant, since manta ray meat is consumed in Ghana. This may presents a health risk, due to a possible accumulation of PGMs in humans.

  7. Trace element accumulation in aquatic plants: a literature review

    SciTech Connect

    Ganje, T.J.; Elseewi, A.A.; Page, A.L.

    1988-01-01

    Trace elements in sediments and its overlying waters are important constituents of an aquatic plant ecosystem. This review was undertaken to evaluate trace element accumulation in aquatic plants and ascertain to what extent sediment and its overlying waters play in trace element accumulation by aquatic plant species. Aquatic vascular plants tend to accumulate trace elements in relation to the trace element concentration of the water body and sediment in which they are grown and the extent of exposure to the water body. Trace element composition of bryophytes and algae is also closely related to composition of their aquatic environment. It is increasingly apparent that sediments and overlying waters alter the bioavailability of trace elements to aquatic plants in both natural and artificial water bodies, particularly where industrial and agricultural waters are discharged into waterways.

  8. The platinum group metals in Younger Dryas Horizons are terrestrial

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Wikes, E.; Kennett, J.; West, A.; Sharma, M.

    2009-12-01

    The Younger Dryas (YD) event, which began 12,900 years ago, was a period of abrupt and rapid cooling in the Northern Hemisphere whose primary cause remains unclear. The prevalent postulated mechanism is a temporary shutdown of the thermohaline circulation following the breakup of an ice dam in North America. Firestone et al. (2007) proposed that the cooling was triggered by multiple cometary airbursts and/or impacts that engendered enormous environmental changes and disrupted the thermohaline circulation. The evidence in support for this hypothesis is a black layer in North America and in Europe marking the YD boundary containing charcoal, soot, carbon spherules and glass-like carbon suggesting extensive and intense forest fires. This layer is also enriched in magnetic grains high in iridium, magnetic microspherules, fullerenes containing extraterrestrial He-3, and nanodiamonds. Whereas the nanodiamonds could be produced in an impact or arrive with the impactor, the cometary burst/impact hypothesis remains highly controversial as the YD horizon lacks important impact markers such as craters, breccias, tektites and shocked minerals. Firestone et al. (2007) contend that bulk of Ir found at the YD boundary is associated with magnetic grains. The key issue is whether this Ir is meteorite derived. We used Ir and Os concentrations and Os isotopes to investigate the provenance of the platinum group metals in the YD horizon. The bulk sediment samples from a number of North American YD sites (Blackwater Draw, Murray Springs, Gainey, Sheriden Cave, and Myrtle Beach) and a site in Europe (Lommel) do not show any traces of meteorite derived Os and Ir. The [Os] = 2 to 45 pg/g in these sediments and the 187Os/188Os ratios are similar to the upper continental crustal values (~1.3), much higher than those in meteorites (0.13). Higher [Os] is observed in Blackwater Draw (= 194 pg/g). However, the Os/Ir ratio in Blackwater Draw is 5 (not 1 as expected for a meteorite) and 187Os/188

  9. Platinum-group minerals in the Santo Tomas II (Philex) porphyry copper-gold deposit, Luzon Island, Philippines

    NASA Astrophysics Data System (ADS)

    Tarkian, M.; Koopmann, G.

    1995-02-01

    Mineralized quartz diorites of the Santo Tomas II porphyry copper-gold deposit, carry high Au contents (average: 1.8 ppm) as well as 160 ppb Pd and 38 ppb Pt. Values of other platinum-group elements (PGE) and rhenium are below the analytical detection limits. There is a significant positive correlation between Au and Cu. The highest Pd values were detected in the most Au- and Cu-rich rocks. Platinum-group minerals (PGM) occur exclusively as inclusions in chalcopyrite and bornite. Potential Pd and Pt contents in sulphide concentrates are estimated at 1.5 g/t and 0.4 g/t, respectively. The precious metal assemblages consist of merenskyite (main PGM), kotulskite, moncheite, native gold, electrum, hessite and petzite. Polyphase fluid inclusions in quartz veinlets, associated with a PGM-bearing bornite-chalcopyrite-magnetite assemblage, are characterized by high salinity (35 to > 60 eq. wt% NaCl) and high trapping temperatures (between 380 and 520 °C). They may represent primary magmatic-hydrothermal fluids, which have been responsible for the transport of Pd, Pt and Au as chloride complexes.

  10. Accumulation of trace elements by Pistia stratiotes: implications for phytoremediation.

    PubMed

    Odjegba, V J; Fasidi, I O

    2004-10-01

    The toxicity of eight potentially toxic trace elements (Ag, Cd, Cr, Cu, Hg, Ni, Pb and Zn) to Pistia stratiotes was examined to determine if this plant showed sufficient tolerance and metal accumulation to be used to phytoremediate waste water and/or natural water bodies polluted with these heavy metals. Young plants of equal size were grown hydroponically and amended with 0, 0.1, 0.3, 0.5, 1.0, 3.0 and 5.0 mM of each heavy metal individually for 21 days. Root elongation as well as emergence of new roots decreased significantly with increase in metal concentrations. The plant had the lowest and the highest tolerance indices for Hg and Zn respectively. The study indicated reduction in the rate of leaf expansion relative to metal type, their concentrations and the duration of exposure. A significant reduction in biomass production was observed in metal treated plants compared with the control plants. The relative growth rate of P. stratiotes was retarded by heavy metals under study. All trace elements accumulated to higher concentrations in root tissue rather than in shoot. Trace element accumulation in tissues and the bioconcentration factors were proportional to the initial concentration of individual metals in the growth medium and the duration of exposure. In terms of trace element removal, P. stratiotes presented differential accumulation and tolerance levels for different metals at similar treatment conditions. The implications of these results for phytoremediation are discussed. PMID:15673213

  11. No Accumulation of Transposable Elements in Asexual Arthropods.

    PubMed

    Bast, Jens; Schaefer, Ina; Schwander, Tanja; Maraun, Mark; Scheu, Stefan; Kraaijeveld, Ken

    2016-03-01

    Transposable elements (TEs) and other repetitive DNA can accumulate in the absence of recombination, a process contributing to the degeneration of Y-chromosomes and other nonrecombining genome portions. A similar accumulation of repetitive DNA is expected for asexually reproducing species, given their entire genome is effectively nonrecombining. We tested this expectation by comparing the whole-genome TE loads of five asexual arthropod lineages and their sexual relatives, including asexual and sexual lineages of crustaceans (Daphnia water fleas), insects (Leptopilina wasps), and mites (Oribatida). Surprisingly, there was no evidence for increased TE load in genomes of asexual as compared to sexual lineages, neither for all classes of repetitive elements combined nor for specific TE families. Our study therefore suggests that nonrecombining genomes do not accumulate TEs like nonrecombining genomic regions of sexual lineages. Even if a slight but undetected increase of TEs were caused by asexual reproduction, it appears to be negligible compared to variance between species caused by processes unrelated to reproductive mode. It remains to be determined if molecular mechanisms underlying genome regulation in asexuals hamper TE activity. Alternatively, the differences in TE dynamics between nonrecombining genomes in asexual lineages versus nonrecombining genome portions in sexual species might stem from selection for benign TEs in asexual lineages because of the lack of genetic conflict between TEs and their hosts and/or because asexual lineages may only arise from sexual ancestors with particularly low TE loads. PMID:26560353

  12. No Accumulation of Transposable Elements in Asexual Arthropods

    PubMed Central

    Bast, Jens; Schaefer, Ina; Schwander, Tanja; Maraun, Mark; Scheu, Stefan; Kraaijeveld, Ken

    2016-01-01

    Transposable elements (TEs) and other repetitive DNA can accumulate in the absence of recombination, a process contributing to the degeneration of Y-chromosomes and other nonrecombining genome portions. A similar accumulation of repetitive DNA is expected for asexually reproducing species, given their entire genome is effectively nonrecombining. We tested this expectation by comparing the whole-genome TE loads of five asexual arthropod lineages and their sexual relatives, including asexual and sexual lineages of crustaceans (Daphnia water fleas), insects (Leptopilina wasps), and mites (Oribatida). Surprisingly, there was no evidence for increased TE load in genomes of asexual as compared to sexual lineages, neither for all classes of repetitive elements combined nor for specific TE families. Our study therefore suggests that nonrecombining genomes do not accumulate TEs like nonrecombining genomic regions of sexual lineages. Even if a slight but undetected increase of TEs were caused by asexual reproduction, it appears to be negligible compared to variance between species caused by processes unrelated to reproductive mode. It remains to be determined if molecular mechanisms underlying genome regulation in asexuals hamper TE activity. Alternatively, the differences in TE dynamics between nonrecombining genomes in asexual lineages versus nonrecombining genome portions in sexual species might stem from selection for benign TEs in asexual lineages because of the lack of genetic conflict between TEs and their hosts and/or because asexual lineages may only arise from sexual ancestors with particularly low TE loads. PMID:26560353

  13. No Accumulation of Transposable Elements in Asexual Arthropods.

    PubMed

    Bast, Jens; Schaefer, Ina; Schwander, Tanja; Maraun, Mark; Scheu, Stefan; Kraaijeveld, Ken

    2016-03-01

    Transposable elements (TEs) and other repetitive DNA can accumulate in the absence of recombination, a process contributing to the degeneration of Y-chromosomes and other nonrecombining genome portions. A similar accumulation of repetitive DNA is expected for asexually reproducing species, given their entire genome is effectively nonrecombining. We tested this expectation by comparing the whole-genome TE loads of five asexual arthropod lineages and their sexual relatives, including asexual and sexual lineages of crustaceans (Daphnia water fleas), insects (Leptopilina wasps), and mites (Oribatida). Surprisingly, there was no evidence for increased TE load in genomes of asexual as compared to sexual lineages, neither for all classes of repetitive elements combined nor for specific TE families. Our study therefore suggests that nonrecombining genomes do not accumulate TEs like nonrecombining genomic regions of sexual lineages. Even if a slight but undetected increase of TEs were caused by asexual reproduction, it appears to be negligible compared to variance between species caused by processes unrelated to reproductive mode. It remains to be determined if molecular mechanisms underlying genome regulation in asexuals hamper TE activity. Alternatively, the differences in TE dynamics between nonrecombining genomes in asexual lineages versus nonrecombining genome portions in sexual species might stem from selection for benign TEs in asexual lineages because of the lack of genetic conflict between TEs and their hosts and/or because asexual lineages may only arise from sexual ancestors with particularly low TE loads.

  14. Hydroponic screening of poplar for trace element tolerance and accumulation.

    PubMed

    Migeon, Aude; Richaud, Pierre; Guinet, Frédéric; Blaudez, Damien; Chalot, Michel

    2012-04-01

    Using the nutrient film technique, we screened 21 clones of poplar for growth in the presence of a mix of trace elements (TE) and for TE accumulation capacities. Poplar cuttings were exposed for four weeks to a multipollution solution consisting in 10 microM Cd, Cu, Ni, and Pb, and 200 microM Zn. Plant biomass and TE accumulation patterns in leaves varied greatly between clones. The highest Cd and Zn concentrations in leaves were detected in P. trichocarpa and P. trichocarpa hybrids, with the clone Skado (P. trichocarpa x P. maximowiczii) accumulating up to 108 mg Cd kg(-1) DW and 1510 mg Zn kg(-1) DW when exposed to a multipollution context. Our data also confirm the importance of pH and multipollution, as these factors greatly affect TE accumulation in above ground biomass. The NFT technique applied here to a large range of poplar clones also revealed the potential of the Rochester, AFO662 and AFO678 poplar clones for use in phytostabilization programs and bioenergy production, where production of less contaminated above ground biomass is suitable.

  15. Residual platinum-group minerals from highly depleted harzburgites of the Lherz massif (France) and their role in HSE fractionation of the mantle

    NASA Astrophysics Data System (ADS)

    Luguet, Ambre; Shirey, Steven B.; Lorand, Jean-Pierre; Horan, Mary F.; Carlson, Richard W.

    2007-06-01

    In order to constrain the highly siderophile elements (HSE: Re and platinum group elements (PGE: Os, Ir, Ru, Pt and Pd)) host mineral(s) in refractory, base metal sulfide-free mantle residues, four very depleted spinel-harzburgites from the Lherz massif (France) have been analyzed for HSE in whole-rock and in major mineral separates (olivine, orthopyroxene, clinopyroxene and spinel) by isotope dilution. In addition, HSE host minerals have been separated and analyzed with a scanning electron microscope. Olivine and spinel show the highest HSE concentration especially for Os, Ir, Ru and Pt (up to 10 ppb) among the modally-major minerals, while the pyroxenes are 1-2 orders of magnitude poorer in HSE. The major minerals account for less than 30% of the whole-rock platinum group element budget. On the other hand, rare, micron to submicron platinum group minerals (PGM), such as Ru-Os ± Ir sulfides and Pt-Ir ± Os alloys, likely located in the intergranular spaces of the refractory depleted harzburgite, account for 50-100% of the HSE budget. The PGM grains are interpreted to be residual, having formed in response to the complete consumption of the base-metal sulfides by the high degree of partial melting (i.e. 23-24%) experienced by these samples. As they sequester the compatible platinum group elements (Os, Ir, Ru and Pt) in the mantle residue, these PGM provide key constraints for the modelling of PGE contents in terrestrial basalts (e.g. the solid/liquid partition coefficients needed to account for the compatible behavior of these elements in the mantle residue) and for understanding the long-lived Os isotope heterogeneities of the upper mantle, especially the old Re-Os ages found in young oceanic mantle. In fact, because of their Os-rich compositions and high melting temperatures, these microphases are likely to preserve their initial Os isotopic compositions unmodified over multiple events of mantle melting and mixing, and therefore generate, through recycling

  16. Germanium and Rare Earth Element accumulation in woody bioenergy crops

    NASA Astrophysics Data System (ADS)

    Hentschel, Werner

    2016-04-01

    Germanium and REEs are strategic elements that are used for high tech devices and engineered systems, however these elements are hardly concentrated into mineable ore deposits. Since these elements occur widely dispersed in the earth crust with concentrations of several mgṡkg‑1 (Ge 1.6 mgṡkg‑1, Nd 25 mgṡkg‑1) a new possibility to gain these elements could be phytomining, a technique that uses plants to extract elements from soils via their roots. Since knowledge about accumulating plant species is quite limited we conducted research on the concentrations of strategic elements in wood and leaves of fast growing tree species (Salix spec., Populus spec., Betula pendula, Alnus glutinosa, Fraxinus excelsior, Acer pseudoplatanus). In total 35 study sites were selected in the mining affected area around Freiberg (Saxony, Germany), differing in their species composition and degree of contamination with toxic trace metals (Pb, As, Cd). On each site plant tissues (wood and leaves, respectively) of different species were sampled. In addition soil samples were taken from a soil depth of 0 - 30 cm and 30 - 60 cm. The aim of our work was to investigate correlations between the concentrations of the target elements in plant tissues and soil characteristics like pH, texture, nutrients and concentrations in six operationally defined soil fractions (mobile, acid soluble, oxidizable, amorphic oxides, crystalline oxides, residual or siliceous). Concentrations of elements in soil extracts and plant tissues were measured with ICP-MS. The element Nd was selected as representative for the group of REEs, since this element showed a high correlation with the concentrations of the other REE We found that the concentration of Nd in the leaves (0.31 mgṡkg‑1Nd) were several times higher than in herbaceous species (0.05 mgṡkg‑1 Nd). The concentration of Ge in leaves were ten times lower than that of Nd whereas in herbaceous species Nd and Ge were in equal magnitude. Within

  17. Germanium and Rare Earth Element accumulation in woody bioenergy crops

    NASA Astrophysics Data System (ADS)

    Hentschel, Werner

    2016-04-01

    Germanium and REEs are strategic elements that are used for high tech devices and engineered systems, however these elements are hardly concentrated into mineable ore deposits. Since these elements occur widely dispersed in the earth crust with concentrations of several mgṡkg-1 (Ge 1.6 mgṡkg-1, Nd 25 mgṡkg-1) a new possibility to gain these elements could be phytomining, a technique that uses plants to extract elements from soils via their roots. Since knowledge about accumulating plant species is quite limited we conducted research on the concentrations of strategic elements in wood and leaves of fast growing tree species (Salix spec., Populus spec., Betula pendula, Alnus glutinosa, Fraxinus excelsior, Acer pseudoplatanus). In total 35 study sites were selected in the mining affected area around Freiberg (Saxony, Germany), differing in their species composition and degree of contamination with toxic trace metals (Pb, As, Cd). On each site plant tissues (wood and leaves, respectively) of different species were sampled. In addition soil samples were taken from a soil depth of 0 - 30 cm and 30 - 60 cm. The aim of our work was to investigate correlations between the concentrations of the target elements in plant tissues and soil characteristics like pH, texture, nutrients and concentrations in six operationally defined soil fractions (mobile, acid soluble, oxidizable, amorphic oxides, crystalline oxides, residual or siliceous). Concentrations of elements in soil extracts and plant tissues were measured with ICP-MS. The element Nd was selected as representative for the group of REEs, since this element showed a high correlation with the concentrations of the other REE We found that the concentration of Nd in the leaves (0.31 mgṡkg-1Nd) were several times higher than in herbaceous species (0.05 mgṡkg-1 Nd). The concentration of Ge in leaves were ten times lower than that of Nd whereas in herbaceous species Nd and Ge were in equal magnitude. Within the tree

  18. Mineral potential for nickel, copper, platinum group elements(PGE), and chromium deposits hosted in ultramafic rocks in the Islamic Republic of Mauritania (phase V, deliverable 67): Chapter G in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

    USGS Publications Warehouse

    Taylor, Cliff D.; Marsh, Erin; Anderson, Eric D.

    2015-01-01

    PRISM-I summary documents mention the presence of mafic-ultramafic igneous intrusive rocks in several areas of Mauritania and a number of chromium (Cr) and copper-nickel (Cu-Ni (±Co, Au)) occurrences associated with them. Permissive geologic settings generally include greenstone belts of any age, layered mafic-ultramafic and unlayered gabbro-anorthosite intrusive complexes in cratonic settings, ophiolite complexes, flood basalt provinces, and fluid-rich shear zones cutting accumulations of mafic-ultramafic rocks. Regions of Mauritania having these characteristics that are discussed in PRISM-I texts include the Mesoarchean greenstone belts of the TasiastTijirit terrane in the southwestern Rgueïbat Shield, two separate layered ultramafic complexes in the Amsaga Complex west of Atar, serpentinized metadunites in Mesoarchean rocks of the Rgueïbat Shield in the Zednes map sheet, several lateritized annular mafic-ultramafic complexes in the Paleoproterozoic northwestern portion of the Rgueïbat Shield, and the serpentinized ophiolitic segments of the Gorgol Noir Complex in the axial portion of the southern Mauritanides. Bureau de Recherches Géologiques et Minières (BRGM) work in the “Extreme Sud” zone also suggests that small copper occurrences associated with the extensive Jurassic microgabbroic intrusive rocks in the Taoudeni Basin of southeastern Mauritania could have potential for magmatic Cu-Ni (PGE, Co, Au) sulfide mineralization. Similarly, Jurassic mafic intrusive rocks in the northeastern Taoudeni Basin may be permissive. Known magmatic Cu-Ni deposits of these types in Mauritania are few in number and some uncertainty exists as to the nature of several of the more important ones.

  19. Permissive tracts for nickel, copper, platinum group elements (PGE), and chromium deposits of Mauritania (phase V, deliverable 66): Chapter G1 in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

    USGS Publications Warehouse

    Taylor, Cliff D.; Horton, John D.

    2012-01-01

    This report contains the USGS results of the PRISM-II Mauritania Minerals Project and is presented in cooperation with the Ministry of Petroleum, Energy, and Mines of the Islamic Republic of Mauritania. The Report is composed of separate chapters consisting of multidisciplinary interpretive reports with accompanying plates on the geology, structure, geochronology, geophysics, hydrogeology, geochemistry, remote sensing (Landsat TM and ASTER), and SRTM and ASTER digital elevation models of Mauritania. The syntheses of these multidisciplinary data formed the basis for additional chapters containing interpretive reports on 12 different commodities and deposit types known to occur in Mauritania, accompanied by countrywide mineral resource potential maps of each commodity/deposit type. The commodities and deposit types represented include: (1) Ni, Cu, PGE, and Cr deposits hosted in ultramafic rocks; (2) orogenic, Carlin-like, and epithermal gold deposits; (3) polymetallic Pb-Zn-Cu vein deposits; (4) sediment-hosted Pb-Zn-Ag deposits of the SEDEX and Mississippi Valley-type; (5) sediment-hosted copper deposits; ( 6) volcanogenic massive sulfide deposits; (7) iron oxide copper-gold deposits; (8) uranium deposits; (9) Algoma-, Superior-, and oolitic-type iron deposits; (10) shoreline Ti-Zr placer deposits; (11) incompatible element deposits hosted in pegmatites, alkaline rocks, and carbonatites, and; (12) industrial mineral deposits. Additional chapters include the Mauritanian National Mineral Deposits Database are accompanied by an explanatory text and the Mauritania Minerals Project GIS that contains all of the interpretive layers created by USGS scientists. Raw data not in the public domain may be obtained from the Ministry of Petroleum, Energy, and Mines in Nouakchott, Mauritania.

  20. Chemical Forms and Distribution of Platinum Group Metals and Technetium During Spent Fuel Reprocessing

    SciTech Connect

    Pokhitonov, Y.

    2007-07-01

    Amongst the fission products present in spent nuclear fuel of Nuclear Power Plants there are considerable quantities of platinum group metals (PGMs): ruthenium, rhodium and palladium. At the same time there are considerable amounts of technetium in the spent fuel, the problem of its removal at radiochemical plants being in operation encountering serious difficulties. Increased interest in this radionuclides is due not only to its rather large yield, but to higher mobility in the environment as well. However, the peculiarities of technetium chemistry in nitric acid solutions create certain problems when trying to separate it as a single product in the course of NPP's spent fuel reprocessing. The object of this work was to conduct a comprehensive analysis of platinum group metals and technetium behavior at various stages of spent fuel reprocessing and to seek the decisions which could make it possible to separate its as a single product. The paper will report data on platinum metals (PGM) and technetium distribution in spent fuel reprocessing products. The description of various techniques for palladium recovery from differing in composition radioactive solutions arising from reprocessing is given. (authors)

  1. Versatile Oxidation Methods for Organic and Inorganic Substrates Catalyzed by Platinum-Group Metals on Carbons.

    PubMed

    Sawama, Yoshinari; Asai, Shota; Monguchi, Yasunari; Sajiki, Hironao

    2016-02-01

    Platinum-group metals on activated carbon catalysts, represented by Pd/C, Ru/C, Rh/C, etc., are widely utilized to accomplish green and sustainable organic reactions due to their favorable features, such as easy handling, recoverability, and reusability. The efficient oxidation methods of various organic compounds using heterogeneous platinum-group metals on carbons with or without added oxidants are summarized in this Personal Account. The oxidation of internal alkynes into diketones was effectively catalyzed by Pd/C in the presence of dimethyl sulfoxide and molecular oxygen or pyridine N-oxide. The Pd/C-catalyzed mild combustion of gaseous hydrogen with molecular oxygen provided hydrogen peroxide, which could be directly utilized for the oxidation of sulfide derivatives into sulfoxides. Furthermore, the Ru/C-catalyzed aerobic oxidation of primary and secondary alcohols gave the corresponding aldehydes and ketones, respectively. On the other hand, the dehydrogenative oxidation of secondary alcohols into ketones was achieved using Rh/C in water, and primary alcohols were effectively dehydrogenated by Pd/C in water under mildly reduced pressure to produce carboxylic acids. PMID:26666634

  2. Platinum group metal particles aggregation in nuclear glass melts under the effect of temperature

    NASA Astrophysics Data System (ADS)

    Hanotin, Caroline; Puig, Jean; Neyret, Muriel; Marchal, Philippe

    2016-08-01

    The viscosity of simulated high level radioactive waste glasses containing platinum group metal particles is studied over a wide range of shear stress, as a function of the particles content and the temperature, thanks to a stress imposed rheometer, coupled to a high-temperature furnace. The system shows a very shear thinning behavior. At high shear rate, the system behaves as a suspension of small clusters and individual particles and is entirely controlled by the viscosity of the glass matrix as classical suspensions. At low shear rate, above a certain fraction in platinum group metal particles, the apparition of macroscopic aggregates made up of chains of RuO2 particles separated by thin layers of glass matrix strongly influences the viscosity of the nuclear glass and leads, in particular, to the apparition of yield stress and thixotropic effects. The maximum size of these clusters as well as their effective volume fraction have been estimated by a balance between Van der Waals attractive forces and hydrodynamic forces due to shear flow. We showed experimentally and theoretically that this aggregation phenomenon is favored by an increase of the temperature, owing to the viscosity decrease of the glass matrix, leading to an unusual increase of the suspension viscosity.

  3. Hydrothermal synthesis of platinum-group-metal nanoparticles by using HEPES as a reductant and stabilizer.

    PubMed

    So, Man-Ho; Ho, Chi-Ming; Chen, Rong; Che, Chi-Ming

    2010-06-01

    Platinum-group-metal (Ru, Os, Rh, Ir, Pd and Pt) nanoparticles are synthesized in an aqueous buffer solution of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (200 mM, pH 7.4) under hydrothermal conditions (180 degrees C). Monodispersed (monodispersity: 11-15%) metal nanoparticles were obtained with an average particle size of less than 5 nm (Ru: 1.8+/-0.2, Os: 1.6+/-0.2, Rh: 4.5+/-0.5, Ir: 2.0+/-0.3, Pd: 3.8+/-0.4, Pt: 1.9+/-0.2 nm). The size, monodispersity, and stability of the as-obtained metal nanoparticles were affected by the HEPES concentration, pH of the HEPES buffer solution, and reaction temperature. HEPES with two tertiary amines (piperazine groups) and terminal hydroxyl groups can act as a reductant and stabilizer. The HEPES molecules can bind to the surface of metal nanoparticles to prevent metal nanoparticles from aggregation. These platinum-group-metal nanoparticles could be deposited onto the surface of graphite, which catalyzed the aerobic oxidation of alcohols to aldehydes. PMID:20512785

  4. Platinum-group minerals in the Limoeiro Ni-Cu-(PGE) sulfide deposit, Brazil: the effect of magmatic and upper amphibolite to granulite metamorphic processes on PGM formation

    NASA Astrophysics Data System (ADS)

    Mota-e-Silva, J.; Prichard, H. M.; Filho, C. F. Ferreira; Fisher, P. C.; McDonald, I.

    2015-12-01

    The Limoeiro Ni-Cu-(platinum-group elements (PGE)) deposit is a recent discovery associated with an igneous tubular conduit system in northeastern Brazil. Representative ores from the deposit have been used for platinum-group minerals (PGM) identification and for PGE in base metal sulfides (BMS) quantification. Ninety-eighty percent of the PGM in the massive sulfide ores is homogeneous Pt-Ni-Bi-bearing merenskyite (PdTe2) enclosed primarily by pyrrhotite, suggesting that it is formed by exsolution from monosulfide solid solution (MSS). Merenskyite gradually but systematically becomes poorer in Pt and Ni with increasing fractionation, which is interpreted to reflect a transition to a more evolved sulfide liquid that segregated in the eastern parts of the intrusion. In massive sulfide ores, merenskyite forms unusually large (up to 5000 μm2) euhedral grains, commonly in contact with spherical silicate inclusions. BMS hosts 12-16 % of the Pd, with the remainder hosted by PGM, which is interpreted to indicate that merenskyite recrystallized from a PGE-bearing bismuthotelluride metamorphic melt formed during high-grade metamorphism. Sperrylite (PtAs2) is the second most abundant PGM (18 % of PGM in disseminated ore) and in contrast to merenskyite occurs mainly as very small (median of 25 μm2) inclusions in high-temperature silicates and oxides, interpreted to have crystallized at high temperatures directly from sulfide blebs that formed and were transported within the Limoeiro magma conduit.

  5. Polyhydrides of Platinum Group Metals: Nonclassical Interactions and σ-Bond Activation Reactions.

    PubMed

    Esteruelas, Miguel A; López, Ana M; Oliván, Montserrat

    2016-08-10

    The preparation, structure, dynamic behavior in solution, and reactivity of polyhydride complexes of platinum group metals, described during the last three decades, are contextualized from both organometallic and coordination chemistry points of view. These compounds, which contain dihydrogen, elongated dihydrogen, compressed dihydride, and classical dihydride ligands promote the activation of B-H, C-H, Si-H, N-H, O-H, C-C, C-N, and C-F, among other σ-bonds. In this review, it is shown that, unlike other more mature areas, the chemistry of polyhydrides offers new exciting conceptual challenges and at the same time the possibility of interacting with other fields including the conversion and storage of regenerative energy, organic synthetic chemistry, drug design, and material science. This wide range of possible interactions foresees promising advances in the near future.

  6. Polyhydrides of Platinum Group Metals: Nonclassical Interactions and σ-Bond Activation Reactions.

    PubMed

    Esteruelas, Miguel A; López, Ana M; Oliván, Montserrat

    2016-08-10

    The preparation, structure, dynamic behavior in solution, and reactivity of polyhydride complexes of platinum group metals, described during the last three decades, are contextualized from both organometallic and coordination chemistry points of view. These compounds, which contain dihydrogen, elongated dihydrogen, compressed dihydride, and classical dihydride ligands promote the activation of B-H, C-H, Si-H, N-H, O-H, C-C, C-N, and C-F, among other σ-bonds. In this review, it is shown that, unlike other more mature areas, the chemistry of polyhydrides offers new exciting conceptual challenges and at the same time the possibility of interacting with other fields including the conversion and storage of regenerative energy, organic synthetic chemistry, drug design, and material science. This wide range of possible interactions foresees promising advances in the near future. PMID:27268136

  7. Nickel and platinum group metal nanoparticle production by Desulfovibrio alaskensis G20.

    PubMed

    Capeness, M J; Edmundson, M C; Horsfall, L E

    2015-12-25

    Desulfovibrio alaskensis G20 is an anaerobic sulfate reducing bacteria. While Desulfovibrio species have previously been shown to reduce palladium and platinum to the zero-state, forming nanoparticles in the process; there have been no reports that D. alaskensis is able to form these nanoparticles. Metal nanoparticles have properties that make them ideal for use in many industrial and medical applications, such as their size and shape giving them higher catalytic activity than the bulk form of the same metal. Nanoparticles of the platinum group metals in particular are highly sought after for their catalytic ability and herein we report the formation of both palladium and platinum nanoparticles by D. alaskensis and the biotransformation of solvated nickel ions to nanoparticle form.

  8. Life cycle benefits of using nanotechnology to stabilize platinum-group metal particles in automotive catalysts.

    PubMed

    Lloyd, Shannon M; Lave, Lester B; Matthews, H Scott

    2005-03-01

    Due to advances in nanotechnology, the approach to catalytic design is transitioning from trial-and-error to planned design and control. Expected advances should enable the design and construction of catalysts to increase reaction speed, yield, and catalyst durability while also reducing active species loading levels. Nanofabrication techniques enabling precise control over the shape, size, and position of nanoscale platinum-group metal (PGM) particles in automotive catalysts should result in reduced PGM loading levels. These reductions would decrease energy consumption, improve environmental quality, and contribute to sustainable resource usage. We estimate the amount of PGM required to meet U.S. vehicle emissions standards through 2030 based on current catalysttechnology. We then estimate the range of PGM that could be saved from potential nanotechnology advances. Finally, we employ economic input-output and process-based life cycle assessment models to estimate the direct and life cycle benefits from reducing PGM mining and refining.

  9. Accumulation of elements by edible mushroom species: part I. Problem of trace element toxicity in mushrooms.

    PubMed

    Mleczek, Mirosław; Siwulski, Marek; Stuper-Szablewska, Kinga; Rissmann, Iwona; Sobieralski, Krzysztof; Goliński, Piotr

    2013-01-01

    The aim of this study was to evaluate Cd, Co, Cu, Hg, Ni, Pb, Sr and Zn accumulation in six edible mushroom species and to assess their risk and benefits to human consumers. Mushrooms (Leccinium aurantiacum, Xerocomus badius, Lactarius deliciosus, Boletus edulis, Cantharellus cibarius and Suillus luteus) were collected from selected regions of Poland during 1990-2010. The highest diversity between studied mushroom species was observed in terms of Cu and Zn accumulation. Significant differences in the accumulation efficiency were found among the six mushroom species examined. The most efficient were Boletus edulis (Cd and Hg), Suillus luteus (Cu and Sr), and Lactarius deliciosus (Pb and Zn). In the case of Co and Ni, the most effective were Xerocomus badius and Leccinium aurantiacum, respectively. The calculated bioconcentration factor (BCF) values of Cd, Cu, Hg, Sr and Zn were > 1 for all species in this study while Co, Ni and Pb usually were bioexcluded (BCF < 1). Additionally, based on the calculated daily intake rates of trace elements determined it can be concluded that occasional consumption of fruiting bodies of L. aurantiacum, X. badius, L. deliciosus, B. edulis, C. cibarius and S. luteus collected in Poland is safe and this finding largely agrees with results from recent studies by other authors.

  10. Noble metals in mid-ocean ridge volcanism: A significant fractionation of gold with respect to platinum group metals

    NASA Technical Reports Server (NTRS)

    Crocket, James H.

    1988-01-01

    Hydrothermal precipitates, black smoker particulate, and massive sulphide dredge samples from the Explorer Ridge on the Juan de Fuca Plate and the TAG hydrothermal area on the Mid-Atlantic Ridge were analyzed for selected noble metals including Au, Ir and Pd by radiochemical neutron activation analysis. The preliminary results indicate that gold contents may reach the ppm range although values in the neighborhood of 100 to 200 ppb are more typical. The platinum group elements (PGE) represented by Ir and Pd are typically less than 0.02 ppb and less than 2 ppb respectively. These abundances represent a significant enrichment of gold relative to the PGE in comparison with average noble metal abundances in mid-ocean ridge basalts (MORB). A partial explanation of this distinctive fractionation can be found in the concepts of sulfur-saturation of basic magma in mid-ocean ridge (MOR) settings, and the origin of MOR hydrothermal fluids. Experimental and petrological data suggest that MORBs are sulfur-saturated at the time of magma generation and that an immiscible sulfide component remains in the mantle residue. Hence, MORBs are noble metal-poor, particularly with respect to PGE. Consequently, black smoker fluids can be expected to reflect the low Ir and Pd contents of the rock column. The average Au content of MORB is 1.3 ppb, and so the rock column is not significantly enriched in Au. The generation of fluids which precipitate solids with 200 ppb Au is apparently dependent on highly efficient fluid chemistry to mobilize Au from the rock column, high Au solubility in seawater hydrothermal fluids and efficient precipitation mechanisms to coprecipitate Au on Fe, Zn and Cu sulfides. Significant differences in these parameters appear to be the ultimate cause of the strong Au-PGE fractionation in the MOR setting. It does not appear from the current data base that MOR hydrothermal fluids are significant contributors to the Ir enrichment seen in Cretaceous-Tertiary boundary

  11. Electrochemical metallization switching with a platinum group metal in different oxides

    NASA Astrophysics Data System (ADS)

    Wang, Zhongrui; Jiang, Hao; Hyung Jang, Moon; Lin, Peng; Ribbe, Alexander; Xia, Qiangfei; Yang, J. Joshua

    2016-07-01

    In a normal electrochemical metallization (ECM) switch, electrochemically active metals, such as Ag and Cu are used to provide mobile ions for the conducting filament. In both ECM and valence change memory (VCM) devices, platinum group metals, such as Pt and Pd, are typically used as the counter electrode and assumed to be chemically and physically inert. In this study, we explore whether the so-called inert metal itself can form a conducting filament and result in repeatable resistance switching. Pd and different oxide host matrices are used for this purpose. We have observed that the transport of oxygen anions dominates over Pd metal cations in ALD deposited AlOx and HfOx. However, in sputtered SiOx, Pd cation transport was revealed, accompanied by the formation of nano-crystalline Pd filament(s) in the junctions. Based on these observations, memristors with reversible and repeatable switching were obtained by using Pd doped SiOx as the switching material.In a normal electrochemical metallization (ECM) switch, electrochemically active metals, such as Ag and Cu are used to provide mobile ions for the conducting filament. In both ECM and valence change memory (VCM) devices, platinum group metals, such as Pt and Pd, are typically used as the counter electrode and assumed to be chemically and physically inert. In this study, we explore whether the so-called inert metal itself can form a conducting filament and result in repeatable resistance switching. Pd and different oxide host matrices are used for this purpose. We have observed that the transport of oxygen anions dominates over Pd metal cations in ALD deposited AlOx and HfOx. However, in sputtered SiOx, Pd cation transport was revealed, accompanied by the formation of nano-crystalline Pd filament(s) in the junctions. Based on these observations, memristors with reversible and repeatable switching were obtained by using Pd doped SiOx as the switching material. Electronic supplementary information (ESI) available

  12. Origin of platinum-group mineral assemblages in a mantle tectonite at Unst deduced from mineral chemistry and osmium isotopes

    NASA Astrophysics Data System (ADS)

    Badanina, Inna Yu.; Lord, Richard A.; Malitch, Kreshimir N.; Meisel, Thomas C.

    2013-04-01

    assemblage is likely to reflect processes such as in-situ serpentinisation, alteration during emplacement or regional greenschist metamorphism. Whole-rock platinum-group element (PGE) concentrations give negatively sloped chondrite-normalized PGE patterns, typical of podiform chromitite, where refractory PGE (Os, Ir and Ru) prevail over less refractory PGE (Rh, Pt and Pd). The osmium isotope results identify similarly 'unradiogenic' 187Os/188Os values for 'primary' and 'secondary' PGM assemblages (with mean 187Os/188Os values of 0.12419 and 0.12464, respectively), being within uncertainty of the chromitite composition (0.1240±0.0006). This implies that the whole-rock Os isotope budget is largely controlled by laurite-dominant assemblages, supporting the conclusion that the 'secondary' PGM assemblage inherited the subchondritic osmium isotope signature of the 'primary' PGM. No evidence for other source contributions during later thermal events has been observed. The Os-isotope data provide further support for an Enstatite Chondrite Reservoir model for the convective upper mantle as defined by Walker et al. (2002) and are consistent with origin of the complex as a Caledonian ophiolite formed in a supra-subduction zone. This study was supported by Russian Foundation for Basic Research (grant 12-05-01166-a to IYuB) and the Uralian Division of Russian Academy of Sciences (project No 12-P-5-1020). References: Andrews, D.R.A., Brenan, J.M. (2002) Phase-equilibrium constraints on the magmatic origin of laurite and Os-Ir alloy. Can. Mineral. 40, 1705-1716. Walker, R.J., Prichard, H.M., Ishiwatari, A., Pimentel, M. (2002) The osmium isotopic composition of convecting upper mantle deduced from ophiolite chromites. Geochim. Cosmochim. Acta 66, 329-345.

  13. Platinum-group minerals in the LG and MG chromitites of the eastern Bushveld Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Oberthür, Thomas; Junge, Malte; Rudashevsky, Nikolay; de Meyer, Eveline; Gutter, Paul

    2016-01-01

    The chromitites of the Bushveld Complex in South Africa contain vast resources of platinum-group elements (PGE); however, except for the economic upper group (UG)-2 chromitite seam, information on the distribution of the PGE in the ores and on the mineralogical nature, assemblages, and proportions of platinum-group minerals (PGM) is essentially missing. In the present geochemical and mineralogical study, PGE concentrates originating from the lower group (LG)-6 and middle group (MG)-1/2 chromitites were investigated with the intention to fill this gap of knowledge. Chondrite-normalized PGE patterns of bulk rock and concentrates are characterized by a positive slope from Os to Rh, a slight drop to Pt, and an increase to Pd again. The pronounced similarities of the PGE patterns indicate similar primary processes of PGE concentration in the chromitites, namely "sulfide control" of the PGE mineralization, i.e., co-precipitation of chromite and sulfide. Further, the primary control of PGE concentration in chromitites appears to be dual in character: (i) base-level concentrations of IPGE (up to ˜500 ppb) hosted within chromite and (ii) co-precipitation of chromite and sulfide, the latter containing virtually the entire remaining PGE budget. Sulfides (chalcopyrite, pentlandite, and pyrite; pyrrhotite is largely missing) are scarce within the chromitites and occur mainly interstitial to chromite grains. Pd and Rh contents in pentlandite are low and erratic. Essentially, the whole PGE inventory of the ores occurs in the form of discrete PGM. The PGM are almost always associated with sulfides. The dominant PGM are various Pt-Pd-Rh sulfides (cooperite/braggite [(Pt,Pd)S] and malanite/cuprorhodsite [CuPt2S4]/[CuRh2S4]), laurite [RuS2], the main carrier of the IPGE (Os, Ir, Ru), sulfarsenides [(Rh,Pt,Ir)AsS], sperrylite [PtAs2], Pt-Fe alloys, and a large variety of mainly Pd-rich PGM. The LG and MG chromitites have many characteristics in common and define a general, "typical

  14. A Capped Octahedral MHC6 Compound of a Platinum Group Metal.

    PubMed

    Eguillor, Beatriz; Esteruelas, Miguel A; Lezáun, Virginia; Oliván, Montserrat; Oñate, Enrique; Tsai, Jui-Yi; Xia, Chuanjun

    2016-06-27

    A MHC6 complex of a platinum group metal with a capped octahedral arrangement of donor atoms around the metal center has been characterized. This osmium compound OsH{κ(2) -C,C-(PhBIm-C6 H4 )}3 , which reacts with HBF4 to afford the 14 e(-) species [Os{κ(2) -C,C-(PhBIm-C6 H4 )}(Ph2 BIm)2 ]BF4 stabilized by two agostic interactions, has been obtained by reaction of OsH6 (PiPr3 )2 with N,N'-diphenylbenzimidazolium chloride ([Ph2 BImH]Cl) in the presence of NEt3 . Its formation takes place through the C,C,C-pincer compound OsH2 {κ(3) -C,C,C-(C6 H4 -BIm-C6 H4 )}(PiPr3 )2 , the dihydrogen derivative OsCl{κ(2) -C,C-(PhBIm-C6 H4 )}(η(2) -H2 )(PiPr3 )2 , and the five-coordinate osmium(II) species OsCl{κ(2) -C,C-(PhBIm-C6 H4 )}(PiPr3 )2 .

  15. Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal-nitrogen coordination

    NASA Astrophysics Data System (ADS)

    Strickland, Kara; Miner, Elise; Jia, Qingying; Tylus, Urszula; Ramaswamy, Nagappan; Liang, Wentao; Sougrati, Moulay-Tahar; Jaouen, Frédéric; Mukerjee, Sanjeev

    2015-06-01

    Replacement of noble metals in catalysts for cathodic oxygen reduction reaction with transition metals mostly create active sites based on a composite of nitrogen-coordinated transition metal in close concert with non-nitrogen-coordinated carbon-embedded metal atom clusters. Here we report a non-platinum group metal electrocatalyst with an active site devoid of any direct nitrogen coordination to iron that outperforms the benchmark platinum-based catalyst in alkaline media and is comparable to its best contemporaries in acidic media. In situ X-ray absorption spectroscopy in conjunction with ex situ microscopy clearly shows nitrided carbon fibres with embedded iron particles that are not directly involved in the oxygen reduction pathway. Instead, the reaction occurs primarily on the carbon-nitrogen structure in the outer skin of the nitrided carbon fibres. Implications include the potential of creating greater active site density and the potential elimination of any Fenton-type process involving exposed iron ions culminating in peroxide initiated free-radical formation.

  16. Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal-nitrogen coordination.

    PubMed

    Strickland, Kara; Miner, Elise; Jia, Qingying; Tylus, Urszula; Ramaswamy, Nagappan; Liang, Wentao; Sougrati, Moulay-Tahar; Jaouen, Frédéric; Mukerjee, Sanjeev

    2015-06-10

    Replacement of noble metals in catalysts for cathodic oxygen reduction reaction with transition metals mostly create active sites based on a composite of nitrogen-coordinated transition metal in close concert with non-nitrogen-coordinated carbon-embedded metal atom clusters. Here we report a non-platinum group metal electrocatalyst with an active site devoid of any direct nitrogen coordination to iron that outperforms the benchmark platinum-based catalyst in alkaline media and is comparable to its best contemporaries in acidic media. In situ X-ray absorption spectroscopy in conjunction with ex situ microscopy clearly shows nitrided carbon fibres with embedded iron particles that are not directly involved in the oxygen reduction pathway. Instead, the reaction occurs primarily on the carbon-nitrogen structure in the outer skin of the nitrided carbon fibres. Implications include the potential of creating greater active site density and the potential elimination of any Fenton-type process involving exposed iron ions culminating in peroxide initiated free-radical formation.

  17. Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal-nitrogen coordination.

    PubMed

    Strickland, Kara; Miner, Elise; Jia, Qingying; Tylus, Urszula; Ramaswamy, Nagappan; Liang, Wentao; Sougrati, Moulay-Tahar; Jaouen, Frédéric; Mukerjee, Sanjeev

    2015-01-01

    Replacement of noble metals in catalysts for cathodic oxygen reduction reaction with transition metals mostly create active sites based on a composite of nitrogen-coordinated transition metal in close concert with non-nitrogen-coordinated carbon-embedded metal atom clusters. Here we report a non-platinum group metal electrocatalyst with an active site devoid of any direct nitrogen coordination to iron that outperforms the benchmark platinum-based catalyst in alkaline media and is comparable to its best contemporaries in acidic media. In situ X-ray absorption spectroscopy in conjunction with ex situ microscopy clearly shows nitrided carbon fibres with embedded iron particles that are not directly involved in the oxygen reduction pathway. Instead, the reaction occurs primarily on the carbon-nitrogen structure in the outer skin of the nitrided carbon fibres. Implications include the potential of creating greater active site density and the potential elimination of any Fenton-type process involving exposed iron ions culminating in peroxide initiated free-radical formation. PMID:26059552

  18. Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal–nitrogen coordination

    PubMed Central

    Strickland, Kara; Miner, Elise; Jia, Qingying; Tylus, Urszula; Ramaswamy, Nagappan; Liang, Wentao; Sougrati, Moulay-Tahar; Jaouen, Frédéric; Mukerjee, Sanjeev

    2015-01-01

    Replacement of noble metals in catalysts for cathodic oxygen reduction reaction with transition metals mostly create active sites based on a composite of nitrogen-coordinated transition metal in close concert with non-nitrogen-coordinated carbon-embedded metal atom clusters. Here we report a non-platinum group metal electrocatalyst with an active site devoid of any direct nitrogen coordination to iron that outperforms the benchmark platinum-based catalyst in alkaline media and is comparable to its best contemporaries in acidic media. In situ X-ray absorption spectroscopy in conjunction with ex situ microscopy clearly shows nitrided carbon fibres with embedded iron particles that are not directly involved in the oxygen reduction pathway. Instead, the reaction occurs primarily on the carbon–nitrogen structure in the outer skin of the nitrided carbon fibres. Implications include the potential of creating greater active site density and the potential elimination of any Fenton-type process involving exposed iron ions culminating in peroxide initiated free-radical formation. PMID:26059552

  19. A Capped Octahedral MHC6 Compound of a Platinum Group Metal.

    PubMed

    Eguillor, Beatriz; Esteruelas, Miguel A; Lezáun, Virginia; Oliván, Montserrat; Oñate, Enrique; Tsai, Jui-Yi; Xia, Chuanjun

    2016-06-27

    A MHC6 complex of a platinum group metal with a capped octahedral arrangement of donor atoms around the metal center has been characterized. This osmium compound OsH{κ(2) -C,C-(PhBIm-C6 H4 )}3 , which reacts with HBF4 to afford the 14 e(-) species [Os{κ(2) -C,C-(PhBIm-C6 H4 )}(Ph2 BIm)2 ]BF4 stabilized by two agostic interactions, has been obtained by reaction of OsH6 (PiPr3 )2 with N,N'-diphenylbenzimidazolium chloride ([Ph2 BImH]Cl) in the presence of NEt3 . Its formation takes place through the C,C,C-pincer compound OsH2 {κ(3) -C,C,C-(C6 H4 -BIm-C6 H4 )}(PiPr3 )2 , the dihydrogen derivative OsCl{κ(2) -C,C-(PhBIm-C6 H4 )}(η(2) -H2 )(PiPr3 )2 , and the five-coordinate osmium(II) species OsCl{κ(2) -C,C-(PhBIm-C6 H4 )}(PiPr3 )2 . PMID:27123555

  20. Fractionation of the platinum-group elments and Re during crystallization of basalt in Kilauea Iki Lava Lake, Hawaii

    USGS Publications Warehouse

    Pitcher, L.; Helz, R.T.; Walker, R.J.; Piccoli, P.

    2009-01-01

    Kilauea Iki lava lake formed during the 1959 summit eruption of Kilauea Volcano, then crystallized and differentiated over a period of 35??years. It offers an opportunity to evaluate the fractionation behavior of trace elements in a uniquely well-documented basaltic system. A suite of 14 core samples recovered from 1967 to 1981 has been analyzed for 5 platinum-group elements (PGE: Ir, Os, Ru, Pt, Pd), plus Re. These samples have MgO ranging from 2.4 to 26.9??wt.%, with temperatures prior to quench ranging from 1140????C to ambient (110????C). Five eruption samples were also analyzed. Osmium and Ru concentrations vary by nearly four orders of magnitude (0.0006-1.40??ppb for Os and 0.0006-2.01??ppb for Ru) and are positively correlated with MgO content. These elements behaved compatibly during crystallization, mostly likely being concentrated in trace phases (alloy or sulfide) present in olivine phenocrysts or included chromite. Iridium also correlates positively with MgO, although less strongly than Os and Ru. The somewhat poorer correlation for Ir, compared with Os and Ru, may reflect variable loss of Ir as volatile IrF6 in some of the most magnesian samples. Rhenium is negatively correlated with MgO, behaving as an incompatible trace element. Its behavior in the lava lake is complicated by apparent volatile loss of Re, as suggested by a decrease in Re concentration with time of quenching for lake samples vs. eruption samples. Platinum and Pd concentrations are negatively, albeit weakly, correlated with MgO, so these elements were modestly incompatible during crystallization of the major silicate phases. Palladium contents peaked before precipitation of immiscible sulfide liquid, however, and decline sharply in the most differentiated samples. In contrast, Pt appears to have been unaffected by sulfide precipitation. Microprobe data confirm that Pd entered the sulfide liquid before Re, and that Pt is not strongly chalcophile in this system. Occasional high Pt values

  1. Morphology of the base of the J-M Reef Package and its bearing on the localization of platinum group metal mineralization in the Stillwater Complex, Montana

    SciTech Connect

    Wolfgram, D. . Dept. of Geological Engineering); Evans-Holmgren, J.A.

    1993-04-01

    Economic concentrations of platinum group metals (PGM) in the Stillwater Complex are typically localized within a unique lithologic sequence, the J-M Reef Package. The J-M Reef Package is generally believed to be the result of the influx of a pulse of undifferentiated' magma into the chamber subsequent to the appearance of plagioclase as a cumulus mineral in the more differentiated resident melt. Underground workings of Stillwater Mining Company, together with over 3,000 underground core holes on 50-foot centers, facilitate the definition of the igneous stratigraphy below the J-M Reef Package and the relationship of its base to it. As much as 350 feet of consolidated footwall igneous cumulates were removed by thermochemical ablation in terraced channels prior to the accumulation of the J-M Reef Package. Distribution of PGM mineralization within the J-M Reef Package, as well as the differential accumulation of the Reef Package itself, is related to channel morphology. Models of ore genesis must account for a new magma pulse that debouched with vigor along the top of the pre-existing cumulus pile.

  2. Multi-element accumulation near Rumex crispus roots under wetland and dryland conditions.

    PubMed

    Kissoon, La Toya T; Jacob, Donna L; Otte, Marinus L

    2010-05-01

    Rumex crispus was grown under wet and dry conditions in two-chamber columns such that the roots were confined to one chamber by a 21 mum nylon mesh, thus creating a soil-root interface ('rhizoplane'). Element concentrations at 3 mm intervals below the 'rhizoplane' were measured. The hypothesis was that metals accumulate near plant roots more under wetland than dryland conditions. Patterns in element distribution were different between the treatments. Under dryland conditions Al, Ba, Cu, Cr, Fe, K, La, Mg, Na, Sr, V, Y and Zn accumulated in soil closest to the roots, above the 'rhizoplane' only. Under wetland conditions Al, Fe, Cr, K, V and Zn accumulated above as well as 3 mm below the 'rhizoplane' whereas La, Sr and Y accumulated 3 mm below the 'rhizoplane' only. Plants on average produced 1.5 times more biomass and element uptake was 2.5 times greater under wetland compared to dryland conditions. PMID:19939528

  3. Accumulation and oxidation of elemental mercury in tropical soils.

    PubMed

    Soares, Liliane Catone; Egreja Filho, Fernando Barboza; Linhares, Lucília Alves; Windmoller, Cláudia Carvalhinho; Yoshida, Maria Irene

    2015-09-01

    The role of chemical and mineralogical soil properties in the retention and oxidation of atmospheric mercury in tropical soils is discussed based on thermal desorption analysis. The retention of gaseous mercury by tropical soils varied greatly both quantitatively and qualitatively with soil type. The average natural mercury content of soils was 0.08 ± 0.06 μg g(-1) with a maximum of 0.215 ± 0.009 μg g(-1). After gaseous Hg(0) incubation experiments, mercury content of investigated soils ranged from 0.6 ± 0.2 to 735 ± 23 μg g(-1), with a mean value of 44 ± 146 μg g(-1). Comparatively, A horizon of almost all soil types adsorbed more mercury than B horizon from the same soil, which demonstrates the key role of organic matter in mercury adsorption. In addition to organic matter, pH and CEC also appear to be important soil characteristics for the adsorption of mercury. All thermograms showed Hg(2+) peaks, which were predominant in most of them, indicating that elemental mercury oxidized in tropical soils. After four months of incubation, the thermograms showed oxidation levels from 70% to 100%. As none of the samples presented only the Hg(0) peak, and the soils retained varying amounts of mercury despite exposure under the same incubation conditions, it became clear that oxidation occurred on soil surface. Organic matter seemed to play a key role in mercury oxidation through complexation/stabilization of the oxidized forms. The lower percentages of available mercury (extracted with KNO3) in A horizons when compared to B horizons support this idea.

  4. Accumulation and oxidation of elemental mercury in tropical soils.

    PubMed

    Soares, Liliane Catone; Egreja Filho, Fernando Barboza; Linhares, Lucília Alves; Windmoller, Cláudia Carvalhinho; Yoshida, Maria Irene

    2015-09-01

    The role of chemical and mineralogical soil properties in the retention and oxidation of atmospheric mercury in tropical soils is discussed based on thermal desorption analysis. The retention of gaseous mercury by tropical soils varied greatly both quantitatively and qualitatively with soil type. The average natural mercury content of soils was 0.08 ± 0.06 μg g(-1) with a maximum of 0.215 ± 0.009 μg g(-1). After gaseous Hg(0) incubation experiments, mercury content of investigated soils ranged from 0.6 ± 0.2 to 735 ± 23 μg g(-1), with a mean value of 44 ± 146 μg g(-1). Comparatively, A horizon of almost all soil types adsorbed more mercury than B horizon from the same soil, which demonstrates the key role of organic matter in mercury adsorption. In addition to organic matter, pH and CEC also appear to be important soil characteristics for the adsorption of mercury. All thermograms showed Hg(2+) peaks, which were predominant in most of them, indicating that elemental mercury oxidized in tropical soils. After four months of incubation, the thermograms showed oxidation levels from 70% to 100%. As none of the samples presented only the Hg(0) peak, and the soils retained varying amounts of mercury despite exposure under the same incubation conditions, it became clear that oxidation occurred on soil surface. Organic matter seemed to play a key role in mercury oxidation through complexation/stabilization of the oxidized forms. The lower percentages of available mercury (extracted with KNO3) in A horizons when compared to B horizons support this idea. PMID:25950134

  5. XAFS Study of Platinum Group Metals Occluded in LaScO3-BASED Perovskite Oxide by Solid-Phase Reaction at High Temperatuers

    NASA Astrophysics Data System (ADS)

    Kageyama, Hiroyuki; Nomura, Katsuhiro; Ohmi, Kentaro; Fujita, Mitsuharu; Ueda, Tetsuya

    2013-07-01

    We have recently found a new preparation route for platinum group metal containing LaScO3-based perovskite oxides. Sr and Ba containing perovskite powder, (La0.7Sr0.2Ba0.1)ScO3-δ (LSBS) reacted with the solid-state platinum group metals at temperatures from 1623 to 1898K in air, and formed platinum group metal containing perovskite oxides without changing the perovskite structure. In this study we made X-ray absorption fine structure (XAFS) analysis of platinum group metals (M = Ir, Pd, Pt, Rh and Ru) occluded in the LSBS perovskite oxide by the solid-phase reaction at high temperatures. The results of the analysis for XANES regions and the radial structure functions showed that the platinum group metals exist not in the metallic but rather in an ionic state in the LSBS perovskite oxide and that the platinum group metals are mainly introduced into the ScO6 octahedral sites in LSBS perovskite structure, respectively.

  6. Root anatomy and element distribution vary between two Salix caprea isolates with different Cd accumulation capacities

    PubMed Central

    Vaculík, Marek; Konlechner, Cornelia; Langer, Ingrid; Adlassnig, Wolfram; Puschenreiter, Markus; Lux, Alexander; Hauser, Marie-Theres

    2012-01-01

    The understanding of the influence of toxic elements on root anatomy and element distribution is still limited. This study describes anatomical responses, metal accumulation and element distribution of rooted cuttings of Salix caprea after exposure to Cd and/or Zn. Differences in the development of apoplastic barriers and tissue organization in roots between two distinct S. caprea isolates with divergent Cd uptake and accumulation capacities in leaves might reflect an adaptive predisposition based on different natural origins. Energy-dispersive X-ray spectroscopy (EDX) revealed that Cd and Zn interfered with the distribution of elements in a tissue- and isolate-specific manner. Zinc, Ca, Mg, Na and Si were enriched in the peripheral bark, K and S in the phloem and Cd in both vascular tissues. Si levels were lower in the superior Cd translocator. Since the cuttings originated from stocks isolated from polluted and unpolluted sites we probably uncovered different strategies against toxic elements. PMID:22325439

  7. [Regulatory role of elements in the formation and accumulation of alkaloids in Papaver somniferum L. seedlings].

    PubMed

    Lovkova, M Ia; Buzuk, G N; Sokolova, S M

    2006-01-01

    The effects of 12 elements on the formation and accumulation of isoquinolines were studied in opium poppy seedlings (Papaver somniferum L.). Three types of concentration dependences of the effects of the elements under study were determined. The elements served as activators (Co, Mo, W, Cr, and Cu) or inhibitors of these processes (B, Fe, V, Mn, and Ca). The molecular mechanisms of action of these regulators are discussed. The optimum concentrations of Co and Mo were tested under combined treatment conditions with these elements.

  8. Platinum group minerals in ophiolitic chromitites from Tehuitzingo (Acatlán complex, southern Mexico): implications for post-magmatic modification

    NASA Astrophysics Data System (ADS)

    Zaccarini, F.; Proenza, J. A.; Ortega-Gutiérrez, F.; Garuti, G.

    2005-07-01

    Podiform chromitite bodies occur in serpentinites at Tehuitzingo (Acatlán complex, southern Mexico). Serpentinite and chromitite are believed to represent a fragment of Paleozoic ophiolitic mantle formed in a supra-subduction zone setting. The ophiolitic mantle sequence is associated with eclogitic rocks, enclosed in a metasedimentary sequence. This association suggests that serpentinites, chromitites and eclogitic rocks underwent a common metamorphic evolution, starting from high pressure (eclogite facies) followed by retrogression (epidote-amphibolite and greenschist facies). The chromitites are strongly altered so that chromite grains are transformed to ferrian chromite; no primary silicates (i.e. of magmatic origin) have been preserved. The chromitites are Al-rich, and contain up to 303 ppb platinum group elements (PGE), with a marked predominance of Os + Ir + Ru over Rh + Pd + Pt, resulting in a characteristic negative-slope of the chondrite-normalized PGE pattern. Consistent with the geochemical data the platinum group minerals (PGM) assemblage is dominated by Ru Os Ir minerals, occurring both as single-phase or as composite grains generally less than 10 µm in size. The PGM mineralogy includes laurite, osmium, irarsite and Ru Fe oxide or hydroxide. Based on textural relations, paragenesis and composition, it was possible to establish that Os-rich laurite and irarsite were early liquidus phases, which now occur as inclusions in unaltered chromite. However, most of the PGM are found in the alteration assemblages of the chromitites in close association with ferrian chromite, chlorite, and heazlewoodite. Laurite from the secondary assemblage is Os-poor and commonly shows overgrowths of Os Ir alloys. Internal zoning of some laurite grains indicates that Os-poor laurite formed from a Os-rich laurite by release of Os and some Ir, that are readily incorporated in the Os Ir alloys. Such process requires a decrease of sulfur fugacity with decreasing temperature; this

  9. Global exploration and production capacity for platinum-group metals from 1995 through 2015

    USGS Publications Warehouse

    Wilburn, David R.

    2012-01-01

    Platinum-group metals (PGMs) are required in a variety of commercial, industrial, and military applications for many existing and emerging technologies, yet the United States is highly dependent on foreign sources of PGMs. Information on global exploration for PGMs since 1995 has been used in this study as a basis for identifying locations where the industry has determined that exploration has provided data sufficient to warrant development of a new mine or expansion of an existing operation or where a significant increase in capacity for PGMs is anticipated by 2015. Discussions include an overview of the industry and the selected sites, factors affecting mineral supply, and circumstances leading to the development of mineral properties with the potential to affect mineral supply. Of the 52 sites or regional operations that were considered in this analysis, 16 sites were producing before 1995, 28 sites commenced production from 1995 through 2010, and 8 sites were expected to begin production from 2011 through 2015 if development plans came to fruition. The United States imports PGMs primarily from Canada, Russia, South Africa, and Zimbabwe to meet increasing demand for these materials in a variety of specialized and high-tech applications. Feed sources of PGMs are changing in South Africa and Russia, which together accounted for about 89 percent of platinum production and 82 percent of palladium production in 2009. A greater amount of South African PGM capacity is likely to come from deeper, higher cost Upper Group Reef seam 2 deposits and deposits in the Eastern Bushveld area. Future Russian PGM capacity is likely to come from ore zones with generally lower PGM content and different platinum-to-palladium ratios than the nickel-rich ore that dominated PGM supply in the 1990s. Because PGM supply from Canada and Russia is derived as a byproduct of copper and nickel mining, the PGM supply from these countries is influenced by economic, environmental, political, and

  10. Global exploration and production capacity for platinum-group metals from 1995 through 2015

    USGS Publications Warehouse

    Wilburn, David R.

    2012-01-01

    Platinum-group metals (PGMs) are required in a variety of commercial, industrial, and military applications for many existing and emerging technologies, yet the United States is highly dependent on foreign sources of PGMs. Information on global exploration for PGMs since 1995 has been used in this study as a basis for identifying locations where the industry has determined that exploration has provided data sufficient to warrant development of a new mine or expansion of an existing operation or where a significant increase in capacity for PGMs is anticipated by 2015. Discussions include an overview of the industry and the selected sites, factors affecting mineral supply, and circumstances leading to the development of mineral properties with the potential to affect mineral supply. Of the 52 sites or regional operations that were considered in this analysis, 16 sites were producing before 1995, 28 sites commenced production from 1995 through 2010, and 8 sites were expected to begin production from 2011 through 2015 if development plans came to fruition. The United States imports PGMs primarily from Canada, Russia, South Africa, and Zimbabwe to meet increasing demand for these materials in a variety of specialized and high-tech applications. Feed sources of PGMs are changing in South Africa and Russia, which together accounted for about 89 percent of platinum production and 82 percent of palladium production in 2009. A greater amount of South African PGM capacity is likely to come from deeper, higher cost Upper Group Reef seam 2 deposits and deposits in the Eastern Bushveld area. Future Russian PGM capacity is likely to come from ore zones with generally lower PGM content and different platinum-to-palladium ratios than the nickel-rich ore that dominated PGM supply in the 1990s. Because PGM supply from Canada and Russia is derived as a byproduct of copper and nickel mining, the PGM supply from these countries is influenced by economic, environmental, political, and

  11. The investigation of heavy element accumulation in some Hydrophilidae (Coleoptera) species.

    PubMed

    Aydoğan, Zeynep; Gürol, Ali; İncekara, Ümit

    2016-04-01

    First of all, this study aimed to find out the measures of some heavy elements (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Pb) as heavy element pollution in Erzurum Province, and secondly to observe whether some hydrophilidae (Coleoptera) species can be used as a biomonitor. Insect samples were collected from five different localities of Erzurum in June, July, and August 2014. Heavy element levels in sediment, water, and insect samples were analyzed by energy-dispersive X-ray fluorescence (EDXRF) spectrometer device. According to the results of analysis derived through EDXRF spectrometry, heavy element concentrations display differences between stations and also species. The results pointed out that the insects were contaminated by the sediment and water; therefore, some hydrophilidae species accumulate higher concentration of elements than their environment. Results for levels in water were compared to national water quality guidelines. The values of some heavy elements found at higher concentration than acceptable limits. PMID:26935735

  12. Peatlands as Dynamic Biogeochemical Ecotones: Elemental Concentrations, Stoichiometries and Accumulation in Peatland Soils of Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Moore, T. R.; Wang, M.; Talbot, J.; Riley, J. L.

    2015-12-01

    Peatlands act as biogeochemical interfaces between terrestrial and aquatic systems and are 'hotspots', particularly for carbon cycling and the accumulation of nutrients and other elements within the peat profile. This results in storage of substantial amounts of carbon, nutrients and metals, particularly in northern peatlands. Using a data base of over 400 peat profiles and 1700 individual peat samples from bog, fen and swamp sites in Ontario, Canada, we examine the profile concentrations of C, N, P, Ca, Mg, K, Hg, Pb, As, Cu, Mn, Zn, Fe and Al, and estimate the storage and accumulation of these elements. We show how these profiles, spatial patterns, stoichiometries and accumulation rates are controlled by biogeochemical processes and influenced by geochemical setting, hydrology, atmospheric input and pollution, and ecological and microbial transformations.

  13. Micro-PIXE studies of elemental distribution in Cd-accumulating Brassica juncea L.

    NASA Astrophysics Data System (ADS)

    Schneider, Thorsten; Haag-Kerwer, Angela; Maetz, Mischa; Niecke, Manfred; Povh, Bogdan; Rausch, Thomas; Schüßler, Arthur

    1999-10-01

    Brassica juncea L. is a high biomass producing crop plant, being able to accumulate Cd and other heavy metals in their roots and shoots. It is a good candidate for efficient phytoextraction of heavy metals - such as Cd - from polluted soils. PIXE and STIM analyses were applied to investigate Cd-uptake in roots and the resulting effects on the elemental distribution of Cd stressed plants. The axial distribution of trace elements as a function of distance from the root tip as well as the radial distribution within cross-sections were analysed. The results are compared with the elemental distribution in control plants.

  14. A Generic Wet Impregnation Method for Preparing Substrate-Supported Platinum Group Metal and Alloy Nanoparticles with Controlled Particle Morphology.

    PubMed

    Zhang, Changlin; Oliaee, Shirin Norooz; Hwang, Sang Youp; Kong, Xiangkai; Peng, Zhenmeng

    2016-01-13

    Mass production of shape-controlled platinum group metal (PGM) and alloy nanoparticles is of high importance for their many fascinating properties in catalysis, electronics, and photonics. Despite of successful demonstrations at milligram scale using wet chemistry syntheses in many fundamental studies, there is still a big gap between the current methods and their real applications due to the complex synthetic procedures, scale-up difficulty, and surface contamination problem of the made particles. Here we report a generic wet impregnation method for facile, surfactant-free, and scalable preparation of nanoparticles of PGMs and their alloys on different substrate materials with controlled particle morphology and clean surface, which bridges the outstanding properties of these nanoparticles to practical important applications. The underlying particle growth and shape formation mechanisms were investigated using a combination of ex situ and in situ characterizations and were attributed to their different interactions with the applied gas molecules.

  15. Linking structure to function: The search for active sites in non-platinum group metal oxygen reduction reaction catalysts

    DOE PAGESBeta

    Holby, Edward F.; Zelenay, Piotr

    2016-05-17

    Atomic-scale structures of oxygen reduction reaction (ORR) active sites in non-platinum group metal (non-PGM) catalysts, made from pyrolysis of carbon, nitrogen, and transition-metal (TM) precursors have been the subject of continuing discussion in the fuel cell electrocatalysis research community. We found that quantum chemical modeling is a path forward for understanding of these materials and how they catalyze the ORR. Here, we demonstrate through literature examples of how such modeling can be used to better understand non-PGM ORR active site relative stability and activity and how such efforts can also aid in the interpretation of experimental signatures produced by thesemore » materials.« less

  16. Placer and lode platinum-group minerals in south Kalimantan, Indonesia: evidence for derivation from Alaskan-type ultramafic intrusions

    USGS Publications Warehouse

    Zientek, M.L.

    1992-01-01

    Platinum-group minerals occur in significant proportions in placer deposits in several localities in South Kalimantan. They consist of Pt-Fe alloy that may be intergrown with or contain inclusions of Ir-Os-Ru alloy, laurite and chromite. Alluvial PGM found along Sungai Tambanio are in part derived from chromatite schlieren in dunitic bodies intruded into clinopyroxene cumulates that may be part of an Alaskan-type ultramafic complex. A chromitite schlieren in serpentinite from one of these dunitic bodies is anomalous in PGE. The chondrite-normalized PGE pattern for this rock, pan concentrates from this area, and PGM concentrates from diamond-Au-PGM placer deposits have an "M'-shaped pattern enriched in Ir and Pt that is typical of PGE-mineralization associated with Alaskan-type ultramafic complexes. -Authors

  17. [Uptake and accumulation characteristics of silicon and other nutritional elements in different age Phyllostachys praecox plants].

    PubMed

    Huang, Zhang-Ting; Jiang, Pei-Kun; Song, Zhao-Liang; Meng, Ci-Fu; Wu, Jia-Sen

    2013-05-01

    The samples of different age (1-4 years old) Phyllostachys praecox plants and their organs (leaf, branch, and culm) were collected from their main production area in Lin' an County, Zhejiang Province of East China to study the contents and the uptake and accumulation characteristics of silicon and other nutritional elements, as well as the interrelations between Si and other nutrient elements. In the P. praecox plants, the C content in aboveground part was in the order of culm > branch> leaf, whereas the Si, N, P, K, Ca, Mg, Al, Fe and Mn contents were in the order of leaf > branch > culm. Mn was mainly accumulated in leaf, while the other nine nutrient elements were mainly accumulated in the culm of 1-year old plants. The average Si content in the aboveground part of 3-4 year old plants was 13.66 g x kg(-1), suggesting that P. praecox belonged to Si accumulation plant. The leaf N, P, K, and Mg contents decreased, while the C, Al, and Mn contents increased with increasing plant age. The Si uptake by the aboveground part was mainly occurred in the second year (57.1%), while the N and K uptake was mainly in the first two years (67.7% - 93.7%). Thereafter, the N and K flowed out from the aboveground part, with the outflow rates reached 19.1% - 39.1% of the total accumulated amounts. The Si in P. praecox was significantly correlated with Ca, Al, and Mn, and negatively correlated with N, P, K, and Mg.

  18. Seedling emergence, growth and trace elements tolerance and accumulation by Lamiaceae species in a mine soil.

    PubMed

    Parra, A; Zornoza, R; Conesa, E; Gómez-López, M D; Faz, A

    2014-10-01

    The potential use of three Laminaceae species (Lavandula dentata, Rosmarinus officinalis and Thymus vulgaris) for the phytostabilisation of a trace elements contaminated (acid) soil has been evaluated. These species were grown in mine tailing soil unamended (TS) and amended with calcium carbonate and pig manure (ATS), and unpolluted substrate for control (CT); plant growth, root characterisation, soil trace elements contents and their accumulation in plants were measured. Results indicated that seed emergence was independent from substrate characteristics, but seedlings died in TS with 40% survival in ATS. The biomass of L. dentata and T. vulgaris and root development in R. officinalis were negatively affected when grown in TS but without differences between ATS and CT. Applicating amendments reduced soil exchangeable and extractable fractions concentrations of trace elements in ATS compared with TS. The establishment of L. dentata and R. officinalis were related to trace elements immobilisation. Trace element concentrations in plants grown in tailing soils were similar to those reported for control, although applicating amendments reduced Zn accumulation in all species, and favoured increased absorption and aerial translocation of As and Pb by L. dentata and T. vulgaris; nonetheless, levels were below toxicity thresholds. Thus, these species fulfill the criteria for phytostabilisation purposes, aided by employing amendments.

  19. Seedling emergence, growth and trace elements tolerance and accumulation by Lamiaceae species in a mine soil.

    PubMed

    Parra, A; Zornoza, R; Conesa, E; Gómez-López, M D; Faz, A

    2014-10-01

    The potential use of three Laminaceae species (Lavandula dentata, Rosmarinus officinalis and Thymus vulgaris) for the phytostabilisation of a trace elements contaminated (acid) soil has been evaluated. These species were grown in mine tailing soil unamended (TS) and amended with calcium carbonate and pig manure (ATS), and unpolluted substrate for control (CT); plant growth, root characterisation, soil trace elements contents and their accumulation in plants were measured. Results indicated that seed emergence was independent from substrate characteristics, but seedlings died in TS with 40% survival in ATS. The biomass of L. dentata and T. vulgaris and root development in R. officinalis were negatively affected when grown in TS but without differences between ATS and CT. Applicating amendments reduced soil exchangeable and extractable fractions concentrations of trace elements in ATS compared with TS. The establishment of L. dentata and R. officinalis were related to trace elements immobilisation. Trace element concentrations in plants grown in tailing soils were similar to those reported for control, although applicating amendments reduced Zn accumulation in all species, and favoured increased absorption and aerial translocation of As and Pb by L. dentata and T. vulgaris; nonetheless, levels were below toxicity thresholds. Thus, these species fulfill the criteria for phytostabilisation purposes, aided by employing amendments. PMID:25065800

  20. Elemental accumulation in lichen transplants in the neighborhood of thermal power stations

    SciTech Connect

    Freitas, M.C.; Reis, M.A.; Alves, L.C.

    1996-12-31

    Lichens are known to be good monitors of air pollution because they easily absorb the chemical elements from air particles. Therefore, the exposure of clean lichens to a polluted region will result in an accumulation of elements emitted by the pollution sources in the lichens. In this work, samples of the lichen Parmelia sulcata were collected from olive tree stems and in a very clean area to gauge pollution. The goal is to obtain a quantitative relation between results obtained via lichens and via airborne particles.

  1. Phytoaccumulation of trace elements by wetland plants: 3. Uptake and accumulation of ten trace elements by twelve plant species

    SciTech Connect

    Qian, J.H.; Zayed, A.; Zhu, Y.L.; Yu, M.; Terry, N.

    1999-10-01

    Interest is increasing in using wetland plants in constructed wetlands to remove toxic elements from polluted wastewater. To identify those wetland plants that hyperaccumulate trace elements, 12 plant species were tested for their efficiency to bioconcentrate 10 potentially toxic trace elements including As, b, Cd, Cr, Cu, Pb, Mn, Hg, Ni, and Se. Individual plants were grown under carefully controlled conditions and supplied with 1 mg L{sup {minus}1} of each trace element individually for 10 d. Except B, all elements accumulated to much higher concentrations in roots than in shoots. Highest shoot tissue concentrations (mg kg{sup {minus}1} DW) of the various trace elements were attained by the following species: umbrella plant (Cyperus alternifolius L.) for Mn (198) and Cr (44); water zinnia (Wedelia trilobata Hitchc.) for Cd (148) and Ni (80); smartweed (Polygonum hydropiperoides Michx.) for Cu (95) and Pb (64); water lettuce (Pistia stratiotes L.) for Hg (92), As (34), and Se (39); and mare's tail (hippuris vulgaris L.) for B (1132). Whereas, the following species attained the highest root tissue concentrations (mg kg{sup {minus}1} DW); stripped rush (Baumia rubiginosa) for Mn (1683); parrot's feather (Myriophyllum brasiliense Camb.) for Cd (1426) and Ni (1077); water lettuce for Cu (1038), Hg (1217), and As (177); smartweed for Cr (2980) and Pb (1882); mare's tail for B (1277); and monkey flower (Mimulus guttatus Fisch.) for Se (384). From a phytoremediation perspective, smartweed was probably the best plant species for trace element removal from wastewater due to its faster growth and higher plant density.

  2. The feasibility of RIMS for the analysis of potentially toxic element accumulation in neural tissue

    SciTech Connect

    Jones, O. Rhodri; Abraham, Christopher J.; Telle, Helmut H.; Oakley, Arthur E.

    1997-01-15

    A feasibility study was conducted into the possibility of using resonance ionisation mass spectrometry for the detection of focal accumulation of neuro-toxic elements in neural tissue. Experiments were performed using a ToFMS system in conjunction with an Ar{sup +} source for target sputtering and a pulsed tuneable dye laser system for resonance ionisation. Detection limits of {approx}3 ppm for Al in brain tissue homogenates were achieved, with a spatial resolution of less than 100 {mu}m.

  3. Accumulation of airborne elements from vehicles in transplanted lichens in urban sites

    SciTech Connect

    Garty, J.; Kauppi, M.; Kauppi, A.

    1996-03-01

    The objective of the current study is to compare the short-term accumulation capacity of two epiphytic lichens characterized by a different type of thallus. The lichens Hypogynmia physodes (L.) Nyl. and Usnea hirta (L.) Weber em. Mot. were transplanted either to the vicinity of streets of low volume and slow traffic or to the vicinity of a highway in the city of Oulu, N. Finland, for a period of 45 d. Eleven elements were analyzed before and after transplantation. The two lichen species were found to possess a similar accumulating capacity for K and Mn. Hypogynmia physodes manifests a higher accumulating capacity than U. hirta for Na, Fe, and Cu. whereas the more sensitive lichen U. hirta exhibits a higher accumulating capacity for Mg, despite a higher primary concentration of these elements in the thallus of H. physodes. Our findings show a relative high concentration of K, Fe, Mg, Zn, Mn, Pb, and Cu in thalli of H. physodes and Mg, Zn, Pb, Cu, and Cd in U. hirta in material transplanted to streets of low volume and slow traffic, over and above the concentration found in thalli retrieved form the vicinity of the highway. This may be explained by the higher rate of abrasion of car engines running idle near traffic lights and by the lesser ventilation near the close-clustered streets of the inner city. 65 refs., 8 tabs.

  4. Photochemistry and charge transfer chemistry of the platinum group elements. Summary progress report, May 1, 1990--April 30, 1993

    SciTech Connect

    Eisenberg, R.

    1992-12-01

    During the past 3 years, progress was made in elucidating the excited state structures of Pt(diimine)(dithiolate) complexes, while more recent efforts focused on the photochemistry of these complexes and electronic structure of other dithiolate systems. A carbonyl-Ir-maleonitrile dithiolate complex is also studied.

  5. Early Diagenesis and Trace Element Accumulation in North American Arctic Margin Sediments

    NASA Astrophysics Data System (ADS)

    Kuzyk, Z. Z. A.; Gobeil, C.; Goni, M. A.; Macdonald, R. W.

    2014-12-01

    Concentrations of redox-sensitive elements (S, Mn, Mo, U, Cd, Re) were analyzed in a set of 27 sediment cores collected along a section extending from the North Bering Sea to Davis Strait via the Canadian Archipelago. Sedimentary distributions and accumulation rates of the elements were used to document the early diagenetic properties of North American Arctic margin sediments and to estimate the importance of this margin as a sink for key elements in the Arctic and global ocean. Distributions of Mn, total S and reduced inorganic S demonstrated that most sediments had relatively thick (>1 cm) surface oxic layers underlain by weakly reducing conditions, reflecting limited sulphate reduction. Strongly reducing conditions sufficient for significant sulphate reduction and strong sedimentary pyrite burial occurred only in certain subregions, including the Bering-Chukchi Shelves, shallow portions of Barrow Canyon, and, to a lesser extent, Lancaster Sound. Estimated accumulation rates of authigenic S, Mo, Cd and U, and total Re displayed marked spatial variability related to sedimentary redox conditions. Strong relationships between the accumulation rates and vertical carbon flux, estimated from regional primary production values and water depth at the coring sites, indicate that the primary driver in the regional patterns is variation in labile carbon forcing. After accounting for the influence of carbon flux, authigenic Mo accumulation rates show a significant relationship with vascular plant input to the sediments, implying that terrestrial organic matter contributes to supporting metabolism in Arctic margin sediments. In the Chukchi Shelf, where our cores represent a sizeable area (~140,000 km2), and where we encountered the strongest reducing conditions and highest authigenic element accumulation rates in sediments, we estimate that the total authigenic S, Mo, Cd and U accumulation may account for as much as 9% of the pyrite S, 14% of the Mo, 6%-24% of the Cd, and 10

  6. Element accumulation, distribution, and phytoremediation potential in selected metallophytes growing in a contaminated area.

    PubMed

    Nadgórska-Socha, Aleksandra; Kandziora-Ciupa, Marta; Ciepał, Ryszard

    2015-07-01

    The distribution of elements in three pseudometallophytes species Cardaminopsis arenosa, Plantago lanceolata, and Plantago major, naturally occurring at metalliferous and non-metalliferous sites in southern Poland, was investigated. The accumulation of Al, Cd, Cu, Fe, Mn, Pb, Zn, as well as Ca, P, Na, and K in shoots and roots was measured. The level of the accumulated trace elements (ATE) was visibly higher in C. arenosa and P. lanceolata from metalliferous sites than non-contaminated ones. However, the level of the accumulated nutrient elements (ANE) was visibly higher only in C. arenosa plants. Also, higher potassium share in ANE was found in the shoots of C. arenosa and Plantago species from metalliferous sites than non-contaminated ones. The highest content of Cd, Zn, Pb, Al, Fe, and Mn was found in C. arenosa, which better reflected metal concentrations in the metalliferous and non-metalliferous soil than other plants. In the studied Plantago species, in almost all cases in all sites TF (translocation coefficient) and MR (mobility ratio) were below 1, which indicates they use the excluder strategy. The best accumulation ability was found for C. arenosa. The higher translocation coefficients (TF > 1) for Zn and Cd in C. arenosa shoots make it suitable for phytoextraction from soil, while the lower translocation ratios (TF < 1) for Zn and Cd in Plantago species and also for Pb in C. arenosa make them suitable for phytostabilization. Almost in all cases the plants had enrichment coefficient >2, which suggested that they may act as indicators of the soil metal contamination.

  7. Element accumulation, distribution, and phytoremediation potential in selected metallophytes growing in a contaminated area.

    PubMed

    Nadgórska-Socha, Aleksandra; Kandziora-Ciupa, Marta; Ciepał, Ryszard

    2015-07-01

    The distribution of elements in three pseudometallophytes species Cardaminopsis arenosa, Plantago lanceolata, and Plantago major, naturally occurring at metalliferous and non-metalliferous sites in southern Poland, was investigated. The accumulation of Al, Cd, Cu, Fe, Mn, Pb, Zn, as well as Ca, P, Na, and K in shoots and roots was measured. The level of the accumulated trace elements (ATE) was visibly higher in C. arenosa and P. lanceolata from metalliferous sites than non-contaminated ones. However, the level of the accumulated nutrient elements (ANE) was visibly higher only in C. arenosa plants. Also, higher potassium share in ANE was found in the shoots of C. arenosa and Plantago species from metalliferous sites than non-contaminated ones. The highest content of Cd, Zn, Pb, Al, Fe, and Mn was found in C. arenosa, which better reflected metal concentrations in the metalliferous and non-metalliferous soil than other plants. In the studied Plantago species, in almost all cases in all sites TF (translocation coefficient) and MR (mobility ratio) were below 1, which indicates they use the excluder strategy. The best accumulation ability was found for C. arenosa. The higher translocation coefficients (TF > 1) for Zn and Cd in C. arenosa shoots make it suitable for phytoextraction from soil, while the lower translocation ratios (TF < 1) for Zn and Cd in Plantago species and also for Pb in C. arenosa make them suitable for phytostabilization. Almost in all cases the plants had enrichment coefficient >2, which suggested that they may act as indicators of the soil metal contamination. PMID:26088758

  8. Trace element accumulation in Cassiopea sp. (Scyphozoa) from urban marine environments in Australia.

    PubMed

    Templeman, Michelle A; Kingsford, Michael J

    2010-03-01

    Jellyfishes are robust, short-lived animals, tolerant to a wide range of environmental conditions and pollutants. The benthic jellyfish, Cassiopea sp. was collected from five locations along the north and eastern coast of Australia and analysed for trace elements to determine if this species has potential as a marine biomonitor. Both the oral arm and bell tissues readily accumulated aluminium, arsenic, barium, cadmium, chromium, copper, iron, manganese and zinc above ambient seawater levels. In contrast, lithium appeared to be actively regulated within the tissues while calcium, magnesium and strontium reflected the ambient environment. The multi-element signatures showed spatial variation, reflecting the geographical separations between locations, with locations closer together showing more similar elemental patterns. The combination of bioaccumulative capacity, life history traits and biophysical aspects indicate that this species has high potential as a biomonitor in coastal marine systems. PMID:19747724

  9. Trace element accumulation in Cassiopea sp. (Scyphozoa) from urban marine environments in Australia.

    PubMed

    Templeman, Michelle A; Kingsford, Michael J

    2010-03-01

    Jellyfishes are robust, short-lived animals, tolerant to a wide range of environmental conditions and pollutants. The benthic jellyfish, Cassiopea sp. was collected from five locations along the north and eastern coast of Australia and analysed for trace elements to determine if this species has potential as a marine biomonitor. Both the oral arm and bell tissues readily accumulated aluminium, arsenic, barium, cadmium, chromium, copper, iron, manganese and zinc above ambient seawater levels. In contrast, lithium appeared to be actively regulated within the tissues while calcium, magnesium and strontium reflected the ambient environment. The multi-element signatures showed spatial variation, reflecting the geographical separations between locations, with locations closer together showing more similar elemental patterns. The combination of bioaccumulative capacity, life history traits and biophysical aspects indicate that this species has high potential as a biomonitor in coastal marine systems.

  10. Accumulation of elements by edible mushroom species II. A comparison of aluminium, barium and nutritional element contents.

    PubMed

    Mleczek, Mirosław; Siwulski, Marek; Stuper-Szablewska, Kinga; Sobieralski, Krzysztof; Magdziak, Zuzanna; Goliński, Piotr

    2013-01-01

    The aim of the study was to compare accumulation efficiency of Al, Ba and nutritional elements (Ca, Fe, K, Mg, Mn, Na) exhibited by six edible mushrooms collected in particular regions of Poland during the last 20 years. The studied mushroom species were Boletus edulis, Cantharellus cibarius, Lactarius deliciosus, Leccinum aurantiacum, Suillus luteus and Xerocomus badius. The highest and the lowest concentrations of the elements in tested mushroom species were 11 - 410, 34 - 337, 16785 - 34600, 140 - 607, 12 - 75 and 16 - 143 mg kg(-1)d.m., respectively. The highest average concentrations of Al, Mg and Mn were observed in Suillus luteus fruiting bodies, while for Ba, Ca, K and Na it was in Lactarius deliciosus. BCF >1 was found for K and Mg in all tested mushroom species and additionally for the highest Ca and Na concentrations of all tested mushroom species except for C. cibarius and S. luteus, respectively. For the other tested elements (Al, Ba, Fe and Mn) BCF values < 1 were recorded.

  11. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India.

    PubMed

    Emmanuel, E S Challaraj; Ananthi, T; Anandkumar, B; Maruthamuthu, S

    2012-03-01

    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  12. Assessing Economic Modulation of Future Critical Materials Use: The Case of Automotive-Related Platinum Group Metals.

    PubMed

    Zhang, Jingshu; Everson, Mark P; Wallington, Timothy J; Field, Frank R; Roth, Richard; Kirchain, Randolph E

    2016-07-19

    Platinum-group metals (PGMs) are technological and economic enablers of many industrial processes. This important role, coupled with their limited geographic availability, has led to PGMs being labeled as "critical materials". Studies of future PGM flows have focused on trends within material flows or macroeconomic indicators. We complement the previous work by introducing a novel technoeconomic model of substitution among PGMs within the automotive sector (the largest user of PGMs) reflecting the rational response of firms to changing prices. The results from the model support previous conclusions that PGM use is likely to grow, in some cases strongly, by 2030 (approximately 45% for Pd and 5% for Pt), driven by the increasing sales of automobiles. The model also indicates that PGM-demand growth will be significantly influenced by the future Pt-to-Pd price ratio, with swings of Pt and Pd demand of as much as 25% if the future price ratio shifts higher or lower even if it stays within the historic range. Fortunately, automotive catalysts are one of the more effectively recycled metals. As such, with proper policy support, recycling can serve to meet some of this growing demand. PMID:27285880

  13. Assessing Economic Modulation of Future Critical Materials Use: The Case of Automotive-Related Platinum Group Metals.

    PubMed

    Zhang, Jingshu; Everson, Mark P; Wallington, Timothy J; Field, Frank R; Roth, Richard; Kirchain, Randolph E

    2016-07-19

    Platinum-group metals (PGMs) are technological and economic enablers of many industrial processes. This important role, coupled with their limited geographic availability, has led to PGMs being labeled as "critical materials". Studies of future PGM flows have focused on trends within material flows or macroeconomic indicators. We complement the previous work by introducing a novel technoeconomic model of substitution among PGMs within the automotive sector (the largest user of PGMs) reflecting the rational response of firms to changing prices. The results from the model support previous conclusions that PGM use is likely to grow, in some cases strongly, by 2030 (approximately 45% for Pd and 5% for Pt), driven by the increasing sales of automobiles. The model also indicates that PGM-demand growth will be significantly influenced by the future Pt-to-Pd price ratio, with swings of Pt and Pd demand of as much as 25% if the future price ratio shifts higher or lower even if it stays within the historic range. Fortunately, automotive catalysts are one of the more effectively recycled metals. As such, with proper policy support, recycling can serve to meet some of this growing demand.

  14. Determination of platinum group metal catalyst residues in active pharmaceutical ingredients by means of total reflection X-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Marguí, Eva; Queralt, Ignasi; Hidalgo, Manuela

    2013-08-01

    The control of metal catalyst residues (i.e., platinum group metals (PGMs)) in different stages of the manufacturing processes of the active pharmaceutical ingredients (APIs) and, especially, in the final product is crucial. For API specimens, there are strict guidelines to limit the levels of metal residues based on their individual levels of safety concern. For PGMs the concentration limit has been established at 10 mg/kg in the API. Therefore great effort is currently being devoted to the development of new and simple procedures to control metals in pharmaceuticals. In the present work, an analytical methodology based on benchtop total reflection X-ray fluorescence spectrometry (TXRF) has been developed for the rapid and simple determination of some PGM catalyst impurities (Rh, Pd, Ir and Pt) in different types of API samples. An evaluation of different sample treatments (dissolution and digestion of the solid pharmaceutical samples) has been carried out and the developed methodologies have been validated according to the analytical parameters to be considered and acceptance criteria for PGM determination according to the United States Pharmacopeia (USP). Limits of quantification obtained for PGM metals were in the range of 2-4 mg/kg which are satisfactory according to current legislation. From the obtained results it is shown that the developed TXRF method can be implemented in the pharmaceutical industries to increase productivity of the laboratory; offering an interesting and complementary analytical tool to other atomic spectroscopic methods.

  15. LINE-1 retrotransposable element DNA accumulates in HIV-1-infected cells.

    PubMed

    Jones, R Brad; Song, Haihan; Xu, Yang; Garrison, Keith E; Buzdin, Anton A; Anwar, Naveed; Hunter, Diana V; Mujib, Shariq; Mihajlovic, Vesna; Martin, Eric; Lee, Erika; Kuciak, Monika; Raposo, Rui André Saraiva; Bozorgzad, Ardalan; Meiklejohn, Duncan A; Ndhlovu, Lishomwa C; Nixon, Douglas F; Ostrowski, Mario A

    2013-12-01

    Type 1 long-interspersed nuclear elements (L1s) are autonomous retrotransposable elements that retain the potential for activity in the human genome but are suppressed by host factors. Retrotransposition of L1s into chromosomal DNA can lead to genomic instability, whereas reverse transcription of L1 in the cytosol has the potential to activate innate immune sensors. We hypothesized that HIV-1 infection would compromise cellular control of L1 elements, resulting in the induction of retrotransposition events. Here, we show that HIV-1 infection enhances L1 retrotransposition in Jurkat cells in a Vif- and Vpr-dependent manner. In primary CD4(+) cells, HIV-1 infection results in the accumulation of L1 DNA, at least the majority of which is extrachromosomal. These data expose an unrecognized interaction between HIV-1 and endogenous retrotransposable elements, which may have implications for the innate immune response to HIV-1 infection, as well as for HIV-1-induced genomic instability and cytopathicity.

  16. Accumulation and partitioning of biomass, nutrients, and trace elements in switchgrass for phytoremediation of municipal biosolids.

    PubMed

    Jeke, Nicholson N; Zvomuya, Francis; Ross, Lisette

    2016-09-01

    In situ phytoremediation of municipal biosolids is a promising alternative to the land spreading and landfilling of biosolids from end-of-life municipal lagoons. Accumulation and partitioning of dry matter, nitrogen (N), phosphorus (P), and trace elements were determined in aboveground biomass (AGB) and belowground biomass (BGB) of switchgrass (Panicum virgatum L.) to determine the harvest stage that maximizes phytoextraction of contaminants from municipal biosolids. Seedlings were transplanted into 15-L plastic pails containing 3.9 kg (dry wt.) biosolids. Biomass yield components and contaminant concentrations were assessed every 14 days for up to 161 days. Logistic model fits to biomass yield data indicated no significant differences in asymptotic yield between AGB and BGB. Switchgrass partitioned significantly more N and P to AGB than to BGB. Maximum uptake occurred 86 days after transplanting (DAT) for N and 102 DAT for P. Harvesting at peak aboveground element accumulation removed 5% of N, 1.6% of P, 0.2% of Zn, 0.05% of Cd, and 0.1% of Cr initially present in the biosolids. These results will contribute toward identification of the harvest stage that will optimize contaminant uptake and enhance in situ phytoremediation of biosolids using switchgrass. PMID:26940512

  17. A New Fungal Isolate, Penidiella sp. Strain T9, Accumulates the Rare Earth Element Dysprosium

    PubMed Central

    Horiike, Takumi

    2015-01-01

    With an aim to develop a highly efficient method for the recovery of rare earth elements (REEs) by using microorganisms, we attempted to isolate dysprosium (Dy)-accumulating microorganisms that grow under acidic conditions from environmental samples containing high concentrations of heavy metals. One acidophilic strain, T9, which was isolated from an abandoned mine, decreased the concentration of Dy in medium that contained 100 mg/liter Dy to 53 mg/liter Dy after 3 days of cultivation at pH 2.5. The Dy content in the cell pellet of the T9 strain was 910 μg/mg of dry cells. The T9 strain also accumulated other REEs. Based on the results of 28S-D1/D2 rRNA gene sequencing and morphological characterization, we designated this fungal strain Penidiella sp. T9. Bioaccumulation of Dy was observed on the cell surface of the T9 strain by elemental mapping using scanning electron microscopy-energy dispersive X-ray spectroscopy. Our results indicate that Penidiella sp. T9 has the potential to recover REEs such as Dy from mine drainage and industrial liquid waste under acidic conditions. PMID:25710372

  18. A new fungal isolate, Penidiella sp. strain T9, accumulates the rare earth element dysprosium.

    PubMed

    Horiike, Takumi; Yamashita, Mitsuo

    2015-05-01

    With an aim to develop a highly efficient method for the recovery of rare earth elements (REEs) by using microorganisms, we attempted to isolate dysprosium (Dy)-accumulating microorganisms that grow under acidic conditions from environmental samples containing high concentrations of heavy metals. One acidophilic strain, T9, which was isolated from an abandoned mine, decreased the concentration of Dy in medium that contained 100 mg/liter Dy to 53 mg/liter Dy after 3 days of cultivation at pH 2.5. The Dy content in the cell pellet of the T9 strain was 910 μg/mg of dry cells. The T9 strain also accumulated other REEs. Based on the results of 28S-D1/D2 rRNA gene sequencing and morphological characterization, we designated this fungal strain Penidiella sp. T9. Bioaccumulation of Dy was observed on the cell surface of the T9 strain by elemental mapping using scanning electron microscopy-energy dispersive X-ray spectroscopy. Our results indicate that Penidiella sp. T9 has the potential to recover REEs such as Dy from mine drainage and industrial liquid waste under acidic conditions.

  19. Growth and elemental accumulation by canola on soil amended with coal fly ash

    SciTech Connect

    Yunusa, I.A.M.; Manoharan, V.; DeSilva, D.L.; Eamus, D.; Murray, B.R.; Nissanka, S.P.

    2008-05-15

    To explore the agronomic potential of an Australian coal fly ash, we conducted two glasshouse experiments in which we measured chlorophyll fluorescence, CO{sub 2} assimilation (A), transpiration, stomatal conductance, biomass accumulation, seed yield, and elemental uptake for canola (Brassica napus) grown on soil amended with an alkaline fly ash. In Experiment 1, application of up to 25 Mg/ha of fly ash increased A and plant weight early in the season before flowering and seed yield by up to 21%. However, at larger rates of ash application A, plant growth, chlorophyll concentration, and yield were all reduced. Increases in early vigor and seed yield were associated with enhanced uptake of phosphorus (P) by the plants treated with fly ash. Fly ash application did not influence accumulation of B, Cu, Mo, or Zn in the stems at any stage of plant growth or in the seed at harvest, except Mo concentration, which was elevated in the seed. Accumulation of these elements was mostly in the leaves, where concentrations of Cu and Mo increased with any amount of ash applied while that of B occurred only with ash applied at 625 Mg/ha. In Experiment 2, fly ash applied at 500 Mg/ha and mixed into the whole 30 cm soil core was detrimental to growth and yield of canola, compared with restricting mixing to 5 or 15 cm depth. In contrast, application of ash at 250 Mg/ha with increasing depth of mixing increased A and seed yield. We concluded that fly ash applied at not more than 25 Mg/ha and mixed into the top 10 to 15 cm of soil is sufficient to obtain yield benefits.

  20. Evaluating the abnormal ossification in tibiotarsi of developing chick embryos exposed to 1.0ppm doses of platinum group metals by spectroscopic techniques.

    PubMed

    Stahler, Adam C; Monahan, Jennifer L; Dagher, Jessica M; Baker, Joshua D; Markopoulos, Marjorie M; Iragena, Diane B; NeJame, Britney M; Slaughter, Robert; Felker, Daniel; Burggraf, Larry W; Isaac, Leon A C; Grossie, David; Gagnon, Zofia E; Sizemore, Ioana E Pavel

    2013-04-01

    Platinum group metals (PGMs), i.e., palladium (Pd), platinum (Pt) and rhodium (Rh), are found at pollutant levels in the environment and are known to accumulate in plant and animal tissues. However, little is known about PGM toxicity. Our previous studies showed that chick embryos exposed to PGM concentrations of 1mL of 5.0ppm (LD50) and higher exhibited severe skeletal deformities. This work hypothesized that 1.0ppm doses of PGMs will negatively impact the mineralization process in tibiotarsi. One milliliter of 1.0ppm of Pd(II), Pt(IV), Rh(III) aqueous salt solutions and a PGM-mixture were injected into the air sac on the 7th and 14th day of incubation. Control groups with no-injection and vehicle injections were included. On the 20th day, embryos were sacrificed to analyze the PGM effects on tibiotarsi using four spectroscopic techniques. 1) Micro-Raman imaging: Hyperspectral Raman data were collected on paraffin embedded cross-sections of tibiotarsi, and processed using in-house-written MATLAB codes. Micro-Raman univariate images that were created from the ν1(PO4(3-)) integrated areas revealed anomalous mineral inclusions within the bone marrow for the PGM-mixture treatment. The age of the mineral crystals (ν(CO3(2-))/ν1(PO4(3-))) was statistically lower for all treatments when compared to controls (p≤0.05). 2) FAAS: The percent calcium content of the chemically digested tibiotarsi in the Pd and Pt groups changed by ~45% with respect to the no-injection control (16.1±0.2%). 3) Micro-XRF imaging: Abnormal calcium and phosphorus inclusions were found within the inner longitudinal sections of tibiotarsi for the PGM-mixture treatment. A clear increase in the mineral content was observed for the outer sections of the Pd treatment. 4) ICP-OES: PGM concentrations in tibiotarsi were undetectable (<5ppb). The spectroscopic techniques gave corroborating results, confirmed the hypothesis, and explained the observed pathological (skeletal developmental abnormalities

  1. Growth conditions, elemental accumulation and induced physiological changes in Chinese cabbage.

    PubMed

    Moreno, Diego A; Víllora, Gemma; Ruiz, Juan M; Romero, Luis

    2003-08-01

    Soils contaminated with low levels of heavy metals and other trace elements are now frequently used for vegetable growing. In this situation, heavy metals and trace elements from these polluted soils may accumulate in the agricultural plants being grown in them and thereby enter the human food chain. The objectives of this study are to elucidate the effects of growth conditions, manipulated by the crop covers, on the phytoaccumulation of elements, and to investigate the conceivable influences of these conditions on the plant biochemistry. In three consecutive years of field experiments, open air (T(0)), and floating rowcover treatments (T(1): perforated polyethylene 50 micrometers; T(2): polypropylene 17 gm(-2)) were used to produce different environmental conditions for the growth of Chinese cabbage [Brassica rapa L. (Pekinensis group) cv. 'Nagaoka 50']. Five samplings (whole tops) were carried out from transplanting to harvest and measurements of B, Al, Ag, Si and Ca concentration as well as phenolics (orto-diphenols, total phenols and anthocyanins), pectic fractions, amino acids (histidine, phenylalanine and tyrosine) and polyphenol oxidase activity, were carried out in samples. The T(1) (perforated polyethylene sheet) gave greater B, Al, Ag and Si concentration and phytoextraction (in weight units) than the open-air control. These findings can help to develop new cost-effective techniques for phytoremediation as the application of plastic covers in the field. The build-up of heavy metals in those crops would make the product less suitable for human consumption.

  2. Growth conditions, elemental accumulation and induced physiological changes in Chinese cabbage.

    PubMed

    Moreno, Diego A; Víllora, Gemma; Ruiz, Juan M; Romero, Luis

    2003-08-01

    Soils contaminated with low levels of heavy metals and other trace elements are now frequently used for vegetable growing. In this situation, heavy metals and trace elements from these polluted soils may accumulate in the agricultural plants being grown in them and thereby enter the human food chain. The objectives of this study are to elucidate the effects of growth conditions, manipulated by the crop covers, on the phytoaccumulation of elements, and to investigate the conceivable influences of these conditions on the plant biochemistry. In three consecutive years of field experiments, open air (T(0)), and floating rowcover treatments (T(1): perforated polyethylene 50 micrometers; T(2): polypropylene 17 gm(-2)) were used to produce different environmental conditions for the growth of Chinese cabbage [Brassica rapa L. (Pekinensis group) cv. 'Nagaoka 50']. Five samplings (whole tops) were carried out from transplanting to harvest and measurements of B, Al, Ag, Si and Ca concentration as well as phenolics (orto-diphenols, total phenols and anthocyanins), pectic fractions, amino acids (histidine, phenylalanine and tyrosine) and polyphenol oxidase activity, were carried out in samples. The T(1) (perforated polyethylene sheet) gave greater B, Al, Ag and Si concentration and phytoextraction (in weight units) than the open-air control. These findings can help to develop new cost-effective techniques for phytoremediation as the application of plastic covers in the field. The build-up of heavy metals in those crops would make the product less suitable for human consumption. PMID:12781236

  3. Drought changes the dynamics of trace element accumulation in a Mediterranean Quercus ilex forest.

    PubMed

    Sardans, J; Peñuelas, J

    2007-06-01

    We conducted a field drought manipulation experiment in an evergreen oak Mediterranean forest from 1999 to 2005 to investigate the effects of the increased drought predicted for the next decades on the accumulation of trace elements that can be toxic for animals, in stand biomass, litter and soil. Drought increased concentrations of As, Cd, Ni, Pb and Cr in roots of the dominant tree species, Quercus ilex, and leaf Cd concentrations in Arbutus unedo and of Phillyrea latifolia codominant shrubs. The increased concentration of As and Cd can aggravate the toxic capacity of those two elements, which are already next or within the levels that have been shown to be toxic for herbivores. The study also showed a great reduction in Pb biomass content (100-135 gha(-1)) during the studied period (1999-2005) showing the effectiveness of the law that prohibited leaded fuel after 2001. The results also indicate that drought increases the exportation of some trace elements to continental waters. PMID:17137692

  4. Materials discovery by crystal growth: Lanthanide metal containing oxides of the platinum group metals (Ru, Os, Ir, Rh, Pd, Pt) from molten alkali metal hydroxides

    SciTech Connect

    Mugavero, Samuel J.; Gemmill, William R.; Roof, Irina P.; Loye, Hans-Conrad zur

    2009-07-15

    This review addresses the process of materials discovery via crystal growth, specifically of lanthanide metal containing oxides of the platinum group metals (Ru, Os, Ir, Rh, Pd, Pt). It provides a detailed overview of the use of hydroxide fluxes for crystal growth. The melt chemistry of hydroxide fluxes, specifically, the extensive acid base chemistry, the metal cation solubility, and the ability of hydroxide melts to oxidize metals are described. Furthermore, a general methodology for the successful crystal growth of oxides is provided, including a discussion of experimental considerations, suitable reaction vessels, reaction profiles and temperature ranges. Finally, a compilation of complex platinum group metal oxides recently synthesized using hydroxide melts, focusing on their crystal growth and crystal structures, is included. - Graphical abstract: A review that addresses the process of materials discovery via crystal growth using hydroxide fluxes. It provides a detailed overview of the use of hydroxide fluxes for crystal growth and describes the melt chemistry of hydroxide fluxes, specifically, the extensive acid base chemistry, the metal cation solubility, and the ability of hydroxide melts to oxidize metals. In addition, a compilation of complex platinum group metal oxides recently synthesized using hydroxide melts is included.

  5. Accumulation of potentially toxic elements in plants and their transfer to human food chain.

    PubMed

    Dudka, S; Miller, W P

    1999-07-01

    Contaminated soils can be a source for crop plants of such elements like As, Cd, Cr, Cu, Ni, Pb, and Zn. The excessive transfer of As, Cu, Ni, and Zn to the food chain is controlled by a "soil-plant barrier"; however, for some elements, including Cd, the soil-plant barrier fails. The level of Cd ingested by average person in USA is about 12 micrograms/day, which is relatively low comparing to Risk Reference Dose (70 micrograms Cd/day) established by USEPA. Food of plant origin is a main source of Cd intake by modern society. Fish and shellfish may be a dominant dietary sources of Hg for some human populations. About half of human Pb intake is through food, of which more than half originates from plants. Dietary intake of Cd and Pb may be increased by application of sludges on cropland with already high levels of these metals. Soils amended with sludges in the USA will be permitted (by USEPA-503 regulations) to accumulate Cr, Cd, Cu, Pb, Hg, Ni, and Se, and Zn to levels from 10 to 100 times the present baseline concentrations. These levels are very permissive by international standards. Because of the limited supply of toxicity data obtained from metals applied in sewage sludge, predictions as to the new regulations will protect crop plants from metal toxicities, and food chain from contamination, are difficult to make.

  6. Accumulation of particulate matter and trace elements on vegetation as affected by pollution level, rainfall and the passage of time.

    PubMed

    Przybysz, A; Sæbø, A; Hanslin, H M; Gawroński, S W

    2014-05-15

    Particulate matter is harmful to human health. To reduce its concentration in air, plants could be used as biological filters, accumulating particulate matter on their foliage. In a study carried out at three sites with differing pollution levels and exposure to precipitation, the capacity of evergreen species (Taxus baccata L., Hedera helix L. and Pinus sylvestris L.) to accumulate particulate matter and trace elements from ambient air in urban areas was investigated. The effects of rainfall and the passage of time on particulate matter deposition on foliage were also determined. The results showed that foliage accumulated an increasing quantity of particulate matter in successive months, but the actual amount of particulate matter and trace elements accumulated differed considerably between sites and plant species. The greatest accumulation of air pollutants occurred on the foliage of plants protected from the rain at a site exposed to traffic related pollution and the smallest accumulation at a rural site. Among the species analysed, the deposited mass of particulate matter and trace elements was the greatest on P. sylvestris. In all species, precipitation removed a considerable proportion of particles accumulated on foliage. Most of the removed particulate matter was large size fraction, but little belong to the smallest size fraction. These results showed that both, the dynamics of deposition and leaf washing by rain during the season need to be considered when evaluating the total effect of vegetation in pollutant remediation.

  7. Accumulation of biomass and mineral elements with calendar time by cotton: application of the expanded growth model.

    PubMed

    Overman, Allen R; Scholtz, Richard V

    2013-01-01

    Accumulation of plant biomass (Mg ha(-1)) with calendar time (wk) occurs as a result of photosynthesis for green land-based plants. A corresponding accumulation of mineral elements (kg ha(-1)) such as nitrogen, phosphorus, and potassium occurs from the soil through plant roots. Field data from literature for the warm-season annual cotton (Gossypium hirsutum L.) are used in this analysis. The expanded growth model is used to describe accumulation of biomass and mineral elements with calendar time. The growth model predicts a simple linear relationship between biomass yield and the growth quantifier, which is confirmed with the data. The growth quantifier incorporates the unit processes of distribution of solar energy which drives biomass accumulation by photosynthesis, partitioning of biomass between light-gathering and structural components of the plants, and an aging function. A hyperbolic relationship between plant nutrient uptake and biomass yield is assumed, and is confirmed for the mineral elements nitrogen, phosphorus, and potassium. It is concluded that the rate limiting process in the system is biomass accumulation by photosynthesis and that nutrient accumulation occurs in virtual equilibrium with biomass accumulation. The expanded growth model describes field data from California and Alabama rather well. Furthermore, all model parameters were common for the two sites with the exception of the yield factor A which accounts for differences in soil types, environmental conditions, fertilizer levels, and plant population.

  8. Accumulation of trace elements and organochlorines by surf scoters wintering in the Pacific northwest

    USGS Publications Warehouse

    Henny, C.J.; Blus, L.J.; Grove, R.A.; Thompson, S.P.

    1991-01-01

    Selenium, cadmium, mercury, copper, manganese, zinc, aluminum, lead, PCBs and DDE were accumulated by segments of the surf scoter (Melanitta perspicillata) population that winters in the Pacific Northwest, but whether the uptake occurred on breeding and/or wintering grounds was uncertain for some contaminants. Surf scoters collected in Puget Sound and San Francisco Bay (in another study) during the same period (January 1985) contained similar concentrations of cadmium, but Alsea Bay scoters contained more. Cadmium was inversely related to both liver and body weights of Northwest scoters in January; similar weight losses were reported in experimental laboratory studies. Northwest and north San Francisco Bay scoters contained similar mercury concentrations, but those in south San Francisco Bay contained higher concentrations. San Francisco Bay scoters contained higher arsenic and selenium concentrations than those in the Northwest; however, the 43.4 ppm (geometric mean, dry wt) selenium in livers at Commencement Bay in January was above levels associated with the reproductive problems in aquatic birds at Kesterson National Wildlife Refuge. Even higher concentrations of some elements may be found in surf scoters in March, because a later collection (March) at San Francisco Bay yielded higher concentrations than found there in January. Trace element concentrations in birds at a given wintering location are variable among species and may be influenced by diet, breeding grounds, and physiology (e.g., at Commencement Bay surf scoters with a sediment-associated diet contained 50X more cadmium in their kidneys than did fish-eating western grebes [Aechmophorus occidentalis]). The numerous wildlife species that live on estuaries require further attention.

  9. Trace element differentiation in ferruginous accumulation soil patterns under tropical rainforest of southern Cameroon, the role of climatic change.

    PubMed

    Temgoua, Emile; Pfeifer, Hans-Rudolf; Bitom, Dieudonné

    2003-03-01

    Regions under tropical rainforest cover, such as central Africa and Brazil are characterised by degradation and dismantling of old ferricrete structures. In southern Cameroon, these processes are relayed by present-day ferruginous accumulation soil facies, situated on the middle and the lower part of hill slopes. These facies become progressively harder towards the surface, containing from bottom to top, mainly kaolinite, kaolinite-goethite and Al-rich goethite-hematite, and are discontinuous to the relictic hematite-dominated ferricrete that exist in the upper part of the hill slope. These features were investigated in terms of geochemical differentiation of trace elements. It appears that, in contrast to the old ferricrete facies, the current ferruginous accumulations are enriched in transitional trace elements (V, Cr, Co, Y, Sc) and Pb, while alkali-earth elements are less differentiated. This recent chemical accumulation is controlled both by intense weathering of the granodiorite bedrock and by mobilisation of elements previously accumulated in the old ferricrete. The observed processes are clearly linked to the present-day humid climate with rising groundwater tables. They slowly replace the old ferricretes formed during Cretaceous time under more seasonal climatic conditions, representing an instructive case of continuos global change.

  10. Accumulation of neurotoxic organochlorines and trace elements in brain of female European eel (Anguilla anguilla).

    PubMed

    Bonnineau, C; Scaion, D; Lemaire, B; Belpaire, C; Thomé, J-P; Thonon, M; Leermaker, M; Gao, Y; Debier, C; Silvestre, F; Kestemont, P; Rees, J-F

    2016-07-01

    Xenobiotics such as organochlorine compounds (OCs) and metals have been suggested to play a significant role in the collapse of European eel stocks in the last decades. Several of these pollutants could affect functioning of the nervous system. Still, no information is so far available on levels of potentially neurotoxic pollutants in eel brain. In present study, carried out on female eels caught in Belgian rivers and canals, we analyzed brain levels of potentially-neurotoxic trace elements (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Hg, MeHg, Mn, Ni, Pb, Sn, Sb, Zn) and OCs (Polychlorinated biphenyls, PCBs; Hexachlorocyclohexanes, HCHs; Dichlorodiphenyltrichloroethane and its metabolites, DDTs). Data were compared to levels in liver and muscle tissues. Eel brain contained very high amounts of OCs, superior to those found in the two other tissues. Interestingly, the relative abundance of PCB congeners markedly differed between tissues. In brain, a predominance of low chlorinated PCBs was noted, whereas highly chlorinated congeners prevailed in muscle and liver. HCHs were particularly abundant in brain, which contains the highest amounts of β-HCH and ϒ-HCH. p,p'-DDTs concentration was similar between brain and muscle (i.e., about twice that of liver). A higher proportion of p,p'-DDT was noticed in brain. Except for Cr and inorganic Hg, all potentially neurotoxic metals accumulated in brain to levels equal to or lower than hepatic levels. Altogether, results indicate that eel brain is an important target for organic and, to a lesser extent, for inorganic neurotoxic pollutants.

  11. Accumulation of neurotoxic organochlorines and trace elements in brain of female European eel (Anguilla anguilla).

    PubMed

    Bonnineau, C; Scaion, D; Lemaire, B; Belpaire, C; Thomé, J-P; Thonon, M; Leermaker, M; Gao, Y; Debier, C; Silvestre, F; Kestemont, P; Rees, J-F

    2016-07-01

    Xenobiotics such as organochlorine compounds (OCs) and metals have been suggested to play a significant role in the collapse of European eel stocks in the last decades. Several of these pollutants could affect functioning of the nervous system. Still, no information is so far available on levels of potentially neurotoxic pollutants in eel brain. In present study, carried out on female eels caught in Belgian rivers and canals, we analyzed brain levels of potentially-neurotoxic trace elements (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Hg, MeHg, Mn, Ni, Pb, Sn, Sb, Zn) and OCs (Polychlorinated biphenyls, PCBs; Hexachlorocyclohexanes, HCHs; Dichlorodiphenyltrichloroethane and its metabolites, DDTs). Data were compared to levels in liver and muscle tissues. Eel brain contained very high amounts of OCs, superior to those found in the two other tissues. Interestingly, the relative abundance of PCB congeners markedly differed between tissues. In brain, a predominance of low chlorinated PCBs was noted, whereas highly chlorinated congeners prevailed in muscle and liver. HCHs were particularly abundant in brain, which contains the highest amounts of β-HCH and ϒ-HCH. p,p'-DDTs concentration was similar between brain and muscle (i.e., about twice that of liver). A higher proportion of p,p'-DDT was noticed in brain. Except for Cr and inorganic Hg, all potentially neurotoxic metals accumulated in brain to levels equal to or lower than hepatic levels. Altogether, results indicate that eel brain is an important target for organic and, to a lesser extent, for inorganic neurotoxic pollutants. PMID:27376663

  12. Which Density Functional Is the Best in Computing C-H Activation Energies by Pincer Complexes of Late Platinum Group Metals?

    PubMed

    Lai, Wenzhen; Yao, Jiannian; Shaik, Sason; Chen, Hui

    2012-09-11

    Using the recently proposed corrective LCCSD(T) method as a reference, we systematically assess the widely used approximate density functionals to reproduce C-H bond activation barriers by pincer complexes of the late platinum group transition metals (TMs) (TM = Rh, Pd, Ir, Pt). The pincer ligands explored here cover a wide range of PNP, PCP, POCOP, NCN, and SCS types. Interestingly, B3LYP is found to be the most accurate functional, followed by several others previously identified as well-performing functionals, like B2GP-PLYP, B2-PLYP, and PBE0. However, all tested functionals were found to exhibit the following uniform trends: (1) the DFT barriers for reactions of group 9 TM (Rh and Ir) pincer complexes show higher accuracy compared with those for group 10 TM (Pd and Pt) reactions; (2) within the same group, 5d TM pincer complexes have higher accuracy than 4d TM ones. Consequently, the barriers for C-H activation by Pd(II) pincer complexes were found to be the least accurate among the four TMs in almost all functionals tested here. The DFT empirical dispersion correction (DFT-D3) is shown to have a very small effect on barrier height. This study has some implications for other σ-bond activations like H-H, C-C, and C-halogen bonds by late platinum group pincer complexes.

  13. Comparison of elemental accumulation rates between ferromanganese deposits and sediments in the South Pacific Ocean

    USGS Publications Warehouse

    Kraemer, T.; Schornick, J.C.

    1974-01-01

    Rates of accumulation of Fe and Mn, as well as Cu, Ni, Co, Pb, Zn, Hg, U and Th have been determined for five ferromanganese deposits from four localities in the South Pacific Ocean. Manganese is accumulating in nodules and crusts at a rate roughly equivalent to that found to be accumulating in sediments in the same area. Iron shows a deficiency in accumulation in nodules and crusts with respect to sediments, especially near the continents, but also in the central and south-central Pacific. Copper is accumulating in nodules and crusts at a rate one order of magnitude less than the surrounding sediments. This is interpreted as meaning that most of the Mn is supplied as an authigenic phase to both sediments and nodules while Fe is supplied mostly by ferromanganese micro-nodules and by detrital and adsorbed components of sediments; and Cu is enriched in sediments relative to nodules and crusts most probably through biological activity. ?? 1974.

  14. Trace-element accumulation by Hygrohypnum ochraceum in the upper Rio Grande Basin, Colorado and New Mexico, USA

    SciTech Connect

    Carter, L.F.; Porter, S.D.

    1997-12-01

    Accumulation of 12 trace elements by transplanted aquatic bryophytes (Hygrohypnum ochraceum) was determined at 13 sites in the Rio Grande and tributary streams in southern Colorado and northern New Mexico as part of the US Geological Survey`s National Water-Quality Assessment Program. The purposes of the study were to determine the spatial distribution of trace elements in relation to land-use practices in the upper Rio Grande Basin, compare accumulation rates of metals in bryophytes at sites contaminated by trace elements, and evaluate transplanted aquatic bryophytes as a tool for examining the bioavailability of trace elements in relation to concentrations in water and bed sediment. Concentrations of Cd, Cu, Pb, and Zn in bryophytes, water, and bed sediment were significantly higher at sites that receive drainage from mining areas than at sites near agricultural or urban activities. Concentrations of most trace elements were lower in a tributary stream below an urban source than at sites near mining or agricultural use. Concentrations of Cu and Zn in bryophytes correlated with concentrations in water and bed sediment. In addition, bryophyte concentrations of As, Cd, and Pb correlated with concentrations in bed sediment. Transplanted bryophytes can provide an indication of bioavailability. Rates of accumulation were related to the magnitude of ambient trace-element concentrations; maximal uptake occurred during the first 10 d of exposure. Trace-element concentrations in transplanted bryophytes could potentially be used to predict water and sediment concentrations that represent an integration of conditions over short to intermediate lengths of time, rather than instantaneous conditions as measured using water samples.

  15. Trace-element accumulation by Hygrohypnum ochraceum in the upper Rio Grande Basin, Colorado and New Mexico, Usa

    USGS Publications Warehouse

    Carter, L.F.; Porter, S.D.

    1997-01-01

    Accumulation of 12 trace elements by transplanted aquatic bryophytes (Hygrohypnum ochraceum) was determined at 13 sites in the Rio Grande and tributary streams in southern Colorado and northern New Mexico as part of the U.S. Geological Survey's National Water-Quality Assessment Program. The purposes of the study were to determine the spatial distribution of trace elements in relation to land-use practices in the upper Rio Grande Basin, compare accumulation rates of metals in bryophytes at sites contaminated by trace elements, and evaluate transplanted aquatic bryophytes as a tool for examining the bioavailability of trace elements in relation to concentrations in water and bed sediment. Concentrations of Cd, Cu, Pb, and Zn in bryophytes, water, and bed sediment were significantly higher at sites that receive drainage from mining areas than at sites near agricultural or urban activities. Concentrations of most trace elements were lower in a tributary stream below an urban source than at sites near mining or agricultural use. Concentrations of Cu and Zn in bryophytes correlated with concentrations in water and bed sediment. In addition, bryophyte concentrations of As, Cd, and Pb correlated with concentrations in bed sediment. Transplanted bryophytes can provide an indication of bioavailability. Rates of accumulation were related to the magnitude of ambient trace-element concentrations; maximal uptake occurred during the first 10 d of exposure. Trace-element concentrations in transplanted bryophytes could potentially be used to predict water and sediment concentrations that represent an integration of conditions over short to intermediate lengths of time, rather than instantaneous conditions as measured using water samples.

  16. Decrease in air pollution load in urban environment of Bratislava (Slovakia) inferred from accumulation of metal elements in lichens.

    PubMed

    Guttová, Anna; Lackovičová, Anna; Pišút, Ivan; Pišút, Peter

    2011-11-01

    The study illustrates the response of epiphytic lichens to changing atmospheric conditions in Central Europe, where the emission of air pollutants has significantly decreased from 1990, in the area in and around Bratislava City. Variation in concentrations of seven metal elements (Cu, Cd, Cr, Mn, Ni, Pb and Zn) in the thalli of Evernia prunastri, Hypogymnia physodes and Parmelia sulcata is assessed. Samples of these species were exposed in lichen bags in 39 sites throughout the territory of the city (more than 300 km(2)) during the period December 2006-February 2007. The samples were analyzed by AAS for metal element contents prior to and after exposure. The decrease in air pollution (for all studied elements by more than 90%) corresponded to a decrease in the accumulation of elements in lichen thalli, e.g. the contents of Pb decreased by 69% and of Cd by 34% on average. The results show also variations in accumulation between with different lichen species. The background values of metal element contents in thalli of H. physodes growing in situ were measured in semi-natural sites in Slovakia. It is suggested that these can be used as a reference in large-scale monitoring studies in Central Europe. Analysis of compatible data from the current study, and the study performed at the end of 1990s shows a significant decrease of metal elements in the air pollution load. PMID:21327486

  17. Decrease in air pollution load in urban environment of Bratislava (Slovakia) inferred from accumulation of metal elements in lichens.

    PubMed

    Guttová, Anna; Lackovičová, Anna; Pišút, Ivan; Pišút, Peter

    2011-11-01

    The study illustrates the response of epiphytic lichens to changing atmospheric conditions in Central Europe, where the emission of air pollutants has significantly decreased from 1990, in the area in and around Bratislava City. Variation in concentrations of seven metal elements (Cu, Cd, Cr, Mn, Ni, Pb and Zn) in the thalli of Evernia prunastri, Hypogymnia physodes and Parmelia sulcata is assessed. Samples of these species were exposed in lichen bags in 39 sites throughout the territory of the city (more than 300 km(2)) during the period December 2006-February 2007. The samples were analyzed by AAS for metal element contents prior to and after exposure. The decrease in air pollution (for all studied elements by more than 90%) corresponded to a decrease in the accumulation of elements in lichen thalli, e.g. the contents of Pb decreased by 69% and of Cd by 34% on average. The results show also variations in accumulation between with different lichen species. The background values of metal element contents in thalli of H. physodes growing in situ were measured in semi-natural sites in Slovakia. It is suggested that these can be used as a reference in large-scale monitoring studies in Central Europe. Analysis of compatible data from the current study, and the study performed at the end of 1990s shows a significant decrease of metal elements in the air pollution load.

  18. Accumulation of cadmium, zinc, and copper by Helianthus annuus L.: impact on plant growth and uptake of nutritional elements.

    PubMed

    Rivelli, Anna Rita; De Maria, Susanna; Puschenreiter, Markus; Gherbin, Piergiorgio

    2012-04-01

    We investigated the effects on physiological response, trace elements and nutrients accumulation of sunflower plants grown in soil contaminated with: 5 mg kg(-1) of Cd; 5 and 300 mg kg(-1) of Cd and Zn, respectively; 5, 300, and 400 mg kg(-1) of Cd, Zn, and Cu, respectively. Contaminants applied did not produce large effects on growth, except in Cd-Zn-Cu treatment in which leaf area and total dry matter were reduced, by 15%. The contamination with Cd alone did not affect neither growth nor physiological parameters, despite considerable amounts of Cd accumulated in roots and older leaves, with a high bioconcentration factor from soil to plant. By adding Zn and then Cu to Cd in soil, significant were the toxic effects on chlorophyll content and water relations due to greater accumulation of trace elements in tissues, with imbalances in nutrients uptake. Highly significant was the interaction between shoot elements concentration (Cd, Zn, Cu, Fe, Mg, K, Ca) and treatments. Heavy metals concentrations in roots always exceeded those in stem and leaves, with a lower translocation from roots to shoots, suggesting a strategy of sunflower to compartmentalise the potentially toxic elements in physiologically less active parts in order to preserve younger tissues. PMID:22567714

  19. Biomass, Nutrient, and Trace Element Accumulation and Partitioning in Cattail ( L.) during Wetland Phytoremediation of Municipal Biosolids.

    PubMed

    Jeke, Nicholson N; Zvomuya, Francis; Cicek, Nazim; Ross, Lisette; Badiou, Pascal

    2015-09-01

    Biomass and contaminant accumulation and partitioning in plants determine the harvest stage for optimum contaminant uptake during phytoremediation of municipal biosolids. This wetland microcosm bioassay characterized accumulation and partitioning of biomass, nutrients (N and P), and trace elements (Zn, Cu, Cr, and Cd) in cattail ( L.) in a growth room. Four cattail seedlings were transplanted into each 20-L plastic pail containing 3.9 kg (dry wt.) biosolids from an end-of-life municipal lagoon. A 10-cm-deep water column was maintained above the 12-cm-thick biosolids layer. Plants were harvested every 14 d over a period of 126 d for determination of aboveground biomass (AGB) and belowground biomass (BGB) yields, along with contaminant concentrations in these plant tissues. Logistic model fits to biomass yield data indicated no significant difference in asymptotic yield between AGB and BGB. Aboveground biomass accumulated significantly greater amounts of N and P and lower amounts of trace elements than BGB. Maximum N accumulation in AGB occurred 83 d after transplanting (DAT), and peak P uptake occurred at 86 DAT. Harvesting at maximum aboveground accumulation removed (percent of the initial element concentration in the biosolids) 4% N, 3% P, 0.05% Zn, 0.6% Cu, 0.1% Cd, and 0.2% Cr. Therefore, under the conditions of this study, phytoremediation would be most effective if cattail is harvested at 86 DAT. These results contribute toward the identification of the harvest stage that will optimize contaminant uptake and enhance in situ phytoremediation of biosolids using cattail. PMID:26436271

  20. Heavy element accumulation in Evernia prunastri lichen transplants around a municipal solid waste landfill in central Italy.

    PubMed

    Nannoni, Francesco; Santolini, Riccardo; Protano, Giuseppe

    2015-09-01

    This paper presents the results of a biomonitoring study to evaluate the environmental impact of airborne emissions from a municipal solid waste landfill in central Italy. Concentrations of 11 heavy elements, as well as photosynthetic efficiency and cell membrane integrity were measured in Evernia prunastri lichens transplanted for 4months in 17 monitoring sites around the waste landfill. Heavy element contents were also determined in surface soils. Analytical data indicated that emissions from the landfill affected Cd, Co, Cr, Cu, Ni, Pb, Sb and Zn concentrations in lichens transplanted within the landfill and along the fallout direction. In these sites moderate to severe accumulation of these heavy elements in lichens was coupled with an increase in cell membrane damage and decrease in photosynthetic efficiency. Nevertheless, results indicated that landfill emissions had no relevant impact on lichens, as heavy element accumulation and weak stress symptoms were detected only in lichen transplants from sites close to solid waste. The appropriate management of this landfill poses a low risk of environmental contamination by heavy elements.

  1. Potentially toxic element contamination in soil and accumulation in maize plants in a smelter area in Kosovo.

    PubMed

    Nannoni, Francesco; Rossi, Sara; Protano, Giuseppe

    2016-06-01

    A biogeochemical field study was carried out in the industrial area of Kosovska Mitrovica in northern Kosovo, where agricultural soils were contaminated by potentially toxic elements due to smelting activity. Total and bioavailable contents of As, Cd, Co, Cu, Pb, Sb, U and Zn in soil and their concentrations in maize roots and grains were determined. Soil contamination by As, Cd, Cu, Pb, Sb and Zn was variable from slightly to highly contaminated soils and influenced both the bioavailable fraction and accumulation of these potentially toxic elements in maize tissues. The comparison between potentially toxic element concentrations in roots and grains indicated that maize is able to limit the transfer of non-essential elements to edible parts. The plant-to-soil bioconcentration indices suggested that the transfer of potentially toxic elements from soil to plant was predicted better by bioavailable concentrations than by the total contents. These indices further identified some competitions and interactions among these elements in root uptake and root-to-grain translocation. PMID:26961525

  2. Trace element accumulation in fishes collected from coastal waters of the Caspian Sea.

    PubMed

    Anan, Yasumi; Kunito, Takashi; Tanabe, Shinsuke; Mitrofanov, Igor; Aubrey, David G

    2005-01-01

    Concentrations of 13 trace elements (V, Mn, Cr, Co, Cu, Zn, Se, Mo, Ag, Cd, Hg, Tl and Pb) were determined in muscle of bony fishes collected from coastal areas of the Caspian Sea (Kazakhstan, Azerbaijan, Turkmenistan and Iran). In all the fishes, Zn concentration was highest, followed by Cu, Se, Mn and Co, while levels of toxic elements (Ag, Cd, Cd, Tl and Pb) were relatively low. Concentrations of several elements were significantly varied between the species in each sampling area. For most of the trace elements examined, the concentrations decreased significantly with body weight of fishes. In contrast, a positive correlation with body weight was found for Co, Se and Pb concentrations in one fish species, and Hg in 2 fish species. Geographical difference in the concentrations of trace elements was examined using the Caspian roach collected from five stations of Iranian coastal waters. The concentrations of Co, Mo, Ag, Cd and Tl were higher in fishes from western stations than those from eastern stations, whereas the opposite trend was observed for Hg, indicating that local sources of trace metal pollution may be present in the Iranian coastal areas of the Caspian Sea. Levels of trace elements in Caspian fishes were relatively low in comparison to those of other regions, but Zn and Hg levels in some specimens exceeded the guideline values for food. PMID:16051278

  3. An Untranslated cis-Element Regulates the Accumulation of Multiple C4 Enzymes in Gynandropsis gynandra Mesophyll Cells[OPEN

    PubMed Central

    Burgess, Steven J.; Reyna-Llorens, Ivan; Knerova, Jana; Stanley, Susan

    2016-01-01

    C4 photosynthesis is a complex phenotype that allows more efficient carbon capture than the ancestral C3 pathway. In leaves of C4 species, hundreds of transcripts increase in abundance compared with C3 relatives and become restricted to mesophyll (M) or bundle sheath (BS) cells. However, no mechanism has been reported that regulates the compartmentation of multiple enzymes in M or BS cells. We examined mechanisms regulating CARBONIC ANHYDRASE4 (CA4) in C4 Gynandropsis gynandra. Increased abundance is directed by both the promoter region and introns of the G. gynandra gene. A nine-nucleotide motif located in the 5′ untranslated region (UTR) is required for preferential accumulation of GUS in M cells. This element is present and functional in three additional 5′ UTRs and six 3′ UTRs where it determines accumulation of two isoforms of CA and pyruvate,orthophosphate dikinase in M cells. Although the GgCA4 5′ UTR is sufficient to direct GUS accumulation in M cells, transcripts encoding GUS are abundant in both M and BS. Mutating the GgCA4 5′ UTR abolishes enrichment of protein in M cells without affecting transcript abundance. The work identifies a mechanism that directs cell-preferential accumulation of multiple enzymes required for C4 photosynthesis. PMID:26772995

  4. Evaluation of urban environment pollution based on the accumulation of macro- and trace elements in epiphytic lichens.

    PubMed

    Parzych, Agnieszka; Astel, Aleksander; Zduńczyk, Anna; Surowiec, Tomasz

    2016-01-01

    Nitrogen, phosphorus, potassium, magnesium, zinc, nickel, copper, manganese, iron and lead accumulation properties of three epiphytic lichen species (Hypogymnia physodes (L.) Nyl., Parmelia sulcata Taylor and Xanthoria parietina (L.) Th. Fr.) were compared. An assessment of pollution of the municipal environment in Słupsk (Poland) according to macro- and trace elements was also done. Lichen samples were taken in Autumn 2013 from Betula pendula, Fraxinus excelsior, Acer platanoides, A. pseudoplatanus and Populus sp. trees. Sampling stations comprised of house development areas, green urban parks, vicinity of streets with heavy traffic and industrial enterprises. It was found that lichens represent diverse accumulation properties to pollutants according to the species. X. parietina indicated the highest bioaccumulation in relation to N, K, Mg, Zn and Fe, the thalli of H. physodes accumulated the largest amounts of Ni and Pb, while P. sulcata P and Cu. Manganese was accumulated in similar quantities by all species. Evidences acquired by the use of factor analysis proved that pollution in Słupsk municipal environment is a serious issue with three major sources domination: street dust, marine factor and residual oil combustion. The high-risk areas were detected and visualized using surface maps based on Kriging algorithm. It was seen that the highest pollution occurs in the town centre, while the smallest happened on its outskirts and in urban parks.

  5. Evaluation of urban environment pollution based on the accumulation of macro- and trace elements in epiphytic lichens.

    PubMed

    Parzych, Agnieszka; Astel, Aleksander; Zduńczyk, Anna; Surowiec, Tomasz

    2016-01-01

    Nitrogen, phosphorus, potassium, magnesium, zinc, nickel, copper, manganese, iron and lead accumulation properties of three epiphytic lichen species (Hypogymnia physodes (L.) Nyl., Parmelia sulcata Taylor and Xanthoria parietina (L.) Th. Fr.) were compared. An assessment of pollution of the municipal environment in Słupsk (Poland) according to macro- and trace elements was also done. Lichen samples were taken in Autumn 2013 from Betula pendula, Fraxinus excelsior, Acer platanoides, A. pseudoplatanus and Populus sp. trees. Sampling stations comprised of house development areas, green urban parks, vicinity of streets with heavy traffic and industrial enterprises. It was found that lichens represent diverse accumulation properties to pollutants according to the species. X. parietina indicated the highest bioaccumulation in relation to N, K, Mg, Zn and Fe, the thalli of H. physodes accumulated the largest amounts of Ni and Pb, while P. sulcata P and Cu. Manganese was accumulated in similar quantities by all species. Evidences acquired by the use of factor analysis proved that pollution in Słupsk municipal environment is a serious issue with three major sources domination: street dust, marine factor and residual oil combustion. The high-risk areas were detected and visualized using surface maps based on Kriging algorithm. It was seen that the highest pollution occurs in the town centre, while the smallest happened on its outskirts and in urban parks. PMID:26745547

  6. Trace element accumulation in relation to trophic niches of shorebirds using intertidal mudflats

    NASA Astrophysics Data System (ADS)

    Lucia, Magali; Bocher, Pierrick; Chambosse, Mélanie; Delaporte, Philippe; Bustamante, Paco

    2014-09-01

    This study investigated the link between trace element concentrations and respective diets of two shorebird species present in the Pertuis Charentais, Atlantic coast of France: the Dunlin (Calidris alpina) and Redshank (Tringa totanus). Trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were investigated in the liver, kidney, muscle and feathers of 28 dunlins and 15 redshanks accidentally dead during catches by mist net. Analyses of carbon and nitrogen stable isotope ratios were carried out in liver, muscle and feathers to determine whether differences in diet explained the variations in elemental levels. These results were compared to previous data obtained on two other shorebird species present on the same sites: the Black-tailed Godwit (Limosa limosa) and the Red Knot (Calidris canutus). This study demonstrated that shorebirds of the Pertuis Charentais were characterized by differential trace element bioaccumulation. Arsenic and Se concentrations in internal tissues were elevated in red knots and dunlins, whereas redshanks displayed higher Cd concentrations. These trace element bioaccumulation discrepancies could mainly come from divergences of trophic habits between shorebirds. Species with the highest trophic position displayed the highest Hg concentrations in the liver, muscle and feathers demonstrating therefore the biomagnification potential of this metal, as opposed to Cd and Pb. The same trend was observed in muscle and feathers for Se and only in feathers for As. These data highlighted the need to study several tissues to obtain a full comprehension of trace element exposure and pathways especially for long-distance migrating species using various habitats and sites.

  7. Accumulation and sub-cellular partitioning of metals and As in the clam Venerupis corrugata: Different strategies towards different elements.

    PubMed

    Velez, Cátia; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa

    2016-08-01

    The main goal of the present study was to assess accumulation, tolerance and sub-cellular partitioning of As, Hg, Cd and Pb in Venerupis corrugata. Results showed an increase of elements accumulation in V. corrugata with the increase of exposure. However, organisms presented higher capacity to accumulate Hg, Cd and Pb (BCF ≥ 12.8) than As (BCF ≤ 2.1) and higher accumulation rate for Cd and Pb than for Hg and As. With the increase of Hg exposure concentrations clams tended to increase the amount of metal bound to metal-sensitive fractions, which may explain the mortality recorded at the highest exposure concentration. Cd sub-cellular partitioning showed that with the increase of exposure concentrations V. corrugata increased the amount of metal in the cellular debris fraction, probably bound to the cellular membranes which explain the mortality recorded at the highest concentration. Results on As partitioning demonstrated that most of the metalloid was associated with fractions in the biologically detoxified metal compartment (BDM). Since high mortality was observed in clams exposed to As our results may indicate that this strategy was not enough to prevent clams from toxic effects and mortality occurred. When exposed to Pb most of the metal was in the BDM compartment, but in this case the metal was mostly in the metal-rich granules fraction which seemed to be efficient in preventing clams from toxicity, and no mortality was recorded. Our study further revealed that As and Hg were the most available elements to be biomagnified through the food chain. PMID:27174825

  8. Biochemical performance of native and introduced clam species living in sympatry: The role of elements accumulation and partitioning.

    PubMed

    Velez, Cátia; Leandro, Sérgio; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa

    2015-08-01

    The present study reports metal and arsenic contamination in sediments, as well as element accumulation and partitioning in native (Ruditapes decussatus and Venerupis corrugata) and introduced (Ruditapes philippinarum) clam species living in sympatry at the Óbidos lagoon (Portugal). The biochemical performance and the human health risks derived from the consumption of these species are also discussed. The results obtained showed that R. decussatus was the most abundant species in all the sampling sites, revealing that the introduced clam has not yet supplanted the native species. The concentration of elements was higher in areas with higher Total Organic Matter (TOM) and fines content, being Chromium (Cr), Copper (Cu) and Lead (Pb) the most abundant metals. Clams from these areas showed the highest concentration of elements but the lowest bioaccumulation levels. Furthermore, except for As, higher concentration of elements was found in clams insoluble fraction, the less toxic fraction to the organisms. Due to the low contamination levels and because elements, except As, were mainly allocated to the insoluble fraction, clams presented similar biochemical parameters among distinct areas, with no significant oxidative stress induced. Furthermore, clams from the Óbidos lagoon represent a low health risk to human consumption since, except for As, their contamination levels were below the maximum permissible limits defined by international organizations.

  9. Rice tissue accumulation of particular elements is dependent on the plant’s physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leaves, grain and other parts of a rice plant require mineral nutrients for various metabolic and other physiological functions. Breeders sometimes want to manipulate the element composition of the grain. Nutrient-dense grain, which is primarily seen as a means for improving nutrition in some co...

  10. Field study on the accumulation of trace elements by vegetables produced in the vicinity of abandoned pyrite mines.

    PubMed

    Alvarenga, Paula; Simões, Isabel; Palma, Patrícia; Amaral, Olga; Matos, João Xavier

    2014-02-01

    To evaluate the accumulation of trace elements (TE) by vegetables produced in the vicinity of abandoned pyrite mines, eighteen different small farms were selected near three mines from the Portuguese sector of the Iberian Pyrite Belt (São Domingos, Aljustrel and Lousal). Total and bioavailable As, Cu, Pb, and Zn concentrations were analyzed in the soils, and the same TE were analyzed in three different vegetables, lettuce (Lactuca sativa), coriander (Coriandrum sativum), and cabbage (Brassica oleracea), collected at the same locations. The soils were contaminated with As, Cu, Pb, and Zn, since their total concentrations exceeded the considered soil quality guideline values for plant production in the majority of the sampling sites. The maximum total concentrations for those TE were extremely high in some of the sampling sites (e.g. 1,851 mg As kg(-1) in São Domingos, 1,126 mg Cu kg(-1) in Aljustrel, 4,946 mg Pb kg(-1) in São Domingos, and 1,224 mg Zn kg(-1) in Aljustrel). However, the soils were mainly circumneutral, a factor that contributes to their low bioavailable fractions. As a result, generally, the plants contained levels of these elements characteristic of uncontaminated plants, and accumulation factors for all elements <1, typical of excluder plants. Furthermore, the estimated daily intake (EDI) for Cu and Zn, through the consumption of these vegetables, falls below the recommended upper limit for daily intake of these elements. The sampling site that stood out from the others was located at São João de Negrilhos (Aljustrel), where bioavailable Zn levels were higher, a consequence of the slight acidity of the soil. Therefore, the Zn content in vegetables was also higher, characteristic of contaminated plants, emphasizing the risk of Zn entering the human food chain via the consumption of crops produced on those soils.

  11. Field study on the accumulation of trace elements by vegetables produced in the vicinity of abandoned pyrite mines.

    PubMed

    Alvarenga, Paula; Simões, Isabel; Palma, Patrícia; Amaral, Olga; Matos, João Xavier

    2014-02-01

    To evaluate the accumulation of trace elements (TE) by vegetables produced in the vicinity of abandoned pyrite mines, eighteen different small farms were selected near three mines from the Portuguese sector of the Iberian Pyrite Belt (São Domingos, Aljustrel and Lousal). Total and bioavailable As, Cu, Pb, and Zn concentrations were analyzed in the soils, and the same TE were analyzed in three different vegetables, lettuce (Lactuca sativa), coriander (Coriandrum sativum), and cabbage (Brassica oleracea), collected at the same locations. The soils were contaminated with As, Cu, Pb, and Zn, since their total concentrations exceeded the considered soil quality guideline values for plant production in the majority of the sampling sites. The maximum total concentrations for those TE were extremely high in some of the sampling sites (e.g. 1,851 mg As kg(-1) in São Domingos, 1,126 mg Cu kg(-1) in Aljustrel, 4,946 mg Pb kg(-1) in São Domingos, and 1,224 mg Zn kg(-1) in Aljustrel). However, the soils were mainly circumneutral, a factor that contributes to their low bioavailable fractions. As a result, generally, the plants contained levels of these elements characteristic of uncontaminated plants, and accumulation factors for all elements <1, typical of excluder plants. Furthermore, the estimated daily intake (EDI) for Cu and Zn, through the consumption of these vegetables, falls below the recommended upper limit for daily intake of these elements. The sampling site that stood out from the others was located at São João de Negrilhos (Aljustrel), where bioavailable Zn levels were higher, a consequence of the slight acidity of the soil. Therefore, the Zn content in vegetables was also higher, characteristic of contaminated plants, emphasizing the risk of Zn entering the human food chain via the consumption of crops produced on those soils. PMID:24252198

  12. Accumulation of trace elements and growth responses in Corbicula fluminea downstream of a coal-fired power plant

    SciTech Connect

    Peltier, G.L.; Wright, M.S.; Hopkins, W.A.; Meyer, J.L.

    2009-07-15

    Lentic organisms exposed to coal-fired power plant (CFPP) discharges can have elevated trace element concentrations in their tissues, but this relationship and its potential consequences are unclear for lotic organisms. To explore these patterns in a lotic environment, we transplanted Corbicula fluminea from a reference stream to a stream receiving CFPP discharge. We assessed trace element accumulation and glutathione concentration in clam tissue, shell growth, and condition index at five sites along a contamination gradient. Clams at the most upstream and contaminated site had the highest growth rate, condition index, glutathione concentrations, and concentrations of arsenic (7.85 {+-} 0.25 {mu} g/g (dry mass)), selenium (17.75 {+-} 0.80 {mu} g/g), and cadmium (7.28 {+-} 0.34 {mu} g/g). Mercury concentrations declined from 4.33 {+-} 0.83 to 0.81 {+-} 0.11 {mu} g/g (dry mass) in clams transplanted into the selenium-rich environment nearest the power plant, but this effect was not as evident at less impacted, downstream sites. Even though dilution of trace elements within modest distances from the power plant reduced bioaccumulation potential in clams, long-term loading of trace elements to downstream depositional regions (e.g., slow moving, silty areas) is likely significant.

  13. The Dynamics of the roo Transposable Element In Mutation-Accumulation Lines and Segregating Populations of Drosophila melanogaster

    PubMed Central

    Papaceit, Montserrat; Ávila, Victoria; Aguadé, Montserrat; García-Dorado, Aurora

    2007-01-01

    We estimated the number of copies for the long terminal repeat (LTR) retrotransposable element roo in a set of long-standing Drosophila melanogaster mutation-accumulation full-sib lines and in two large laboratory populations maintained with effective population size ∼500, all of them derived from the same isogenic origin. Estimates were based on real-time quantitative PCR and in situ hybridization. Considering previous estimates of roo copy numbers obtained at earlier stages of the experiment, the results imply a strong acceleration of the insertion rate in the accumulation lines. The detected acceleration is consistent with a model where only one (maybe a few) of the ∼70 roo copies in the ancestral isogenic genome was active and each active copy caused new insertions with a relatively high rate (∼10−2), with new inserts being active copies themselves. In the two laboratory populations, however, a stabilized copy number or no accelerated insertion was found. Our estimate of the average deleterious viability effects per accumulated insert [E(s) < 0.003] is too small to account for the latter finding, and we discuss the mechanisms that could contain copy number. PMID:17890368

  14. Accumulation of chemical elements in the raised peatbogs of the subtaiga Trans-Urals in the Holocene

    NASA Astrophysics Data System (ADS)

    Larina, N. S.; Larin, S. I.; Merkushina, G. A.

    2014-07-01

    The results of studying the variability of the geochemical parameters of the layers of the Sartamskii upland peatbog in the south of Tyumen oblast based on the radiocarbon time scale are given. Four basic types of peat and stages of peat deposits formation in the Holocene are distinguished: the organomineral layer of the sediments in a paleolake (up to 5065 ± 60 years ago), the low moor layer (4300-4900 years ago), the transitional layer (3100-4300 years ago), and the high moor peat (250-3100 years ago). The upper peat layer (last 200-300 years) significantly differs from its main portion; in particular, it is characterized by an increased ash content and the accumulation of a number of elements. The relationship between the various characteristics of the deposit is analyzed using principal component analysis, and the conditions of the formation of the peat deposit in different time periods are estimated, including the climatic conditions (in relative units). The anthropogenic signal of the accumulation of some elements in wetland systems is identified.

  15. Accumulation of heavy metals and trace elements in fluvial sediments received effluents from traditional and semiconductor industries

    PubMed Central

    Hsu, Liang-Ching; Huang, Ching-Yi; Chuang, Yen-Hsun; Chen, Ho-Wen; Chan, Ya-Ting; Teah, Heng Yi; Chen, Tsan-Yao; Chang, Chiung-Fen; Liu, Yu-Ting; Tzou, Yu-Min

    2016-01-01

    Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Here, contents of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) and trace elements (Ga, In, Mo, and Se) were determined for river waters and bed sediments that received sewage discharged from traditional and semiconductor industries. We used principal component analysis (PCA) to determine the metal distribution in relation to environmental factors such as pH, EC, and organic matter (OM) contents in the river basin. While water PCA categorized discharged metals into three groups that implied potential origins of contamination, sediment PCA only indicated a correlation between metal accumulation and OM contents. Such discrepancy in metal distribution between river water and bed sediment highlighted the significance of physical-chemical properties of sediment, especially OM, in metal retention. Moreover, we used Se XANES as an example to test the species transformation during metal transportation from effluent outlets to bed sediments and found a portion of Se inventory shifted from less soluble elemental Se to the high soluble and toxic selenite and selenate. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for bed sediments. PMID:27681994

  16. Accumulation of heavy metals and trace elements in fluvial sediments received effluents from traditional and semiconductor industries

    NASA Astrophysics Data System (ADS)

    Hsu, Liang-Ching; Huang, Ching-Yi; Chuang, Yen-Hsun; Chen, Ho-Wen; Chan, Ya-Ting; Teah, Heng Yi; Chen, Tsan-Yao; Chang, Chiung-Fen; Liu, Yu-Ting; Tzou, Yu-Min

    2016-09-01

    Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Here, contents of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) and trace elements (Ga, In, Mo, and Se) were determined for river waters and bed sediments that received sewage discharged from traditional and semiconductor industries. We used principal component analysis (PCA) to determine the metal distribution in relation to environmental factors such as pH, EC, and organic matter (OM) contents in the river basin. While water PCA categorized discharged metals into three groups that implied potential origins of contamination, sediment PCA only indicated a correlation between metal accumulation and OM contents. Such discrepancy in metal distribution between river water and bed sediment highlighted the significance of physical-chemical properties of sediment, especially OM, in metal retention. Moreover, we used Se XANES as an example to test the species transformation during metal transportation from effluent outlets to bed sediments and found a portion of Se inventory shifted from less soluble elemental Se to the high soluble and toxic selenite and selenate. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for bed sediments.

  17. Influences of major nutrient elements on Pb accumulation of two crops from a Pb-contaminated soil.

    PubMed

    Lin, Changcun; Zhu, Tingcheng; Liu, Li; Wang, Deli

    2010-02-15

    To know about the effect of major nutrient elements on various forms of Pb and metal extraction, a greenhouse experiment was conducted to assess the effects of various major nutrient elements on Pb accumulation in two crops (Spinacia oleracea, SO and Sonchus arvensis, SA) in Changchun, China. Results indicated that, for SO, the Pb concentrations in both shoots and roots had no difference with increasing nutrients except for low nutrient treatment (1/2H). For SA, high nutrient treatments (2H and 3H) resulted in higher Pb concentrations in roots than low and standard nutrient treatments (1/2H and C), but high Pb concentration in shoot appeared in low and highest nutrient treatments (1/2H and 3H). The nitrogenous nutrient treatment (2N) had the most effect of increasing Pb concentrations in roots of SO and SA. The potassic and phosphorus nutrient treatments (2K and 2P) had little effect on the Pb concentrations in plant tissues for SO. Pb concentration in SO was lower than SA. Because of the higher total biomass in SO than SA, the ability to Pb accumulation in SO was better than SA. Sequential extraction results indicated that the addition of soil amendments transform soil Pb from bioavailable fractions to non-bioavailable fraction substantially. The results suggest that nitrogen fertilizer for SO and phosphorus fertilizer for SA are the most effective materials for the remediation of Pb-contaminated soils, and increase the tolerance of crops to Pb contamination.

  18. Trace element accumulation and trophic relationships in aquatic organisms of the Sundarbans mangrove ecosystem (Bangladesh).

    PubMed

    Borrell, Asunción; Tornero, Victoria; Bhattacharjee, Dola; Aguilar, Alex

    2016-03-01

    The Sundarbans forest is the largest and one of the most diverse and productive mangrove ecosystems in the world. Located at the northern shoreline of the Bay of Bengal in the Indian Ocean and straddling India and Bangladesh, the mangrove forest is the result of three primary river systems that originate further north and northwest. During recent decades, the Sundarbans have been subject to increasing pollution by trace elements caused by the progressive industrialization and urbanization of the basins of these three rivers. As a consequence, animals and plants dwelling downstream in the mangroves are exposed to these pollutants in varying degrees, and may potentially affect human health when consumed. The aim of the present study was to analyse the concentrations of seven trace elements (Zn, Cu, Cr, Hg, Pb, Cd and As) in 14 different animal and plant species collected in the Sundarbans in Bangladesh to study their transfer through the food web and to determine whether their levels in edible species are acceptable for human consumption. δ(15)N values were used as a proxy of the trophic level. A decrease in Zn, Cu, Pb and Cd levels was observed with increasing trophic position. Trace element concentrations measured in all organisms were, in general, lower than the concentrations obtained in other field studies conducted in the same region. When examined with respect to accepted international standards, the concentrations observed in fish and crustaceans were generally found to be safe for human consumption. However, the levels of Zn in Scylla serrata and Cr and Cd in Harpadon nehereus exceeded the proposed health advisory levels and may be of concern for human health.

  19. Trace element accumulation and trophic relationships in aquatic organisms of the Sundarbans mangrove ecosystem (Bangladesh).

    PubMed

    Borrell, Asunción; Tornero, Victoria; Bhattacharjee, Dola; Aguilar, Alex

    2016-03-01

    The Sundarbans forest is the largest and one of the most diverse and productive mangrove ecosystems in the world. Located at the northern shoreline of the Bay of Bengal in the Indian Ocean and straddling India and Bangladesh, the mangrove forest is the result of three primary river systems that originate further north and northwest. During recent decades, the Sundarbans have been subject to increasing pollution by trace elements caused by the progressive industrialization and urbanization of the basins of these three rivers. As a consequence, animals and plants dwelling downstream in the mangroves are exposed to these pollutants in varying degrees, and may potentially affect human health when consumed. The aim of the present study was to analyse the concentrations of seven trace elements (Zn, Cu, Cr, Hg, Pb, Cd and As) in 14 different animal and plant species collected in the Sundarbans in Bangladesh to study their transfer through the food web and to determine whether their levels in edible species are acceptable for human consumption. δ(15)N values were used as a proxy of the trophic level. A decrease in Zn, Cu, Pb and Cd levels was observed with increasing trophic position. Trace element concentrations measured in all organisms were, in general, lower than the concentrations obtained in other field studies conducted in the same region. When examined with respect to accepted international standards, the concentrations observed in fish and crustaceans were generally found to be safe for human consumption. However, the levels of Zn in Scylla serrata and Cr and Cd in Harpadon nehereus exceeded the proposed health advisory levels and may be of concern for human health. PMID:26748006

  20. Tricholoma matsutake can absorb and accumulate trace elements directly from rock fragments in the shiro.

    PubMed

    Vaario, Lu-Min; Pennanen, Taina; Lu, Jinrong; Palmén, Jorma; Stenman, Jarkko; Leveinen, Jussi; Kilpeläinen, Petri; Kitunen, Veikko

    2015-07-01

    Tricholoma matsutake, a highly valued delicacy in Japan and East Asia, is an ectomycorrhizal fungus typically found in a complex soil community of mycorrhizae, soil microbes, and host-tree roots referred to as the shiro in Japan. A curious characteristic of the shiro is an assortment of small rock fragments that have been implicated as a direct source of minerals and trace elements for the fungus. In this study, we measured the mineral content of 14 samples of shiro soil containing live matsutake mycelium and the extent to which the fungus can absorb minerals directly from the rock fragments. X-ray powder diffraction identified major phases of quartz, microcline, orthoclase, and albite in all shiro samples. PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting and direct sequencing confirmed the presence of T. matsutake on 32 of 33 rock fragments. Piloderma sp. co-occurred on 40% of fragments and was positively correlated with locations known to produce good mushroom crops. The ability of T. matsutake to absorb trace elements directly from rock fragments was examined in vitro on nutrient-agar plates supplemented with rock fragments from the shiro. In comparison to the mineral content of tissues grown on control media, the concentration of Al, Cu, Fe, Mn, P, and Zn increased from 1.1 to 106.4 times for both T. matsutake and Piloderma sp. Mineral content of dried sporocarps sampled from the study site partially reflected the results of the in vitro study. We discuss the implications of our results with respect to the natural development and artificial culture of this important fungus. PMID:25355073

  1. Tricholoma matsutake can absorb and accumulate trace elements directly from rock fragments in the shiro.

    PubMed

    Vaario, Lu-Min; Pennanen, Taina; Lu, Jinrong; Palmén, Jorma; Stenman, Jarkko; Leveinen, Jussi; Kilpeläinen, Petri; Kitunen, Veikko

    2015-07-01

    Tricholoma matsutake, a highly valued delicacy in Japan and East Asia, is an ectomycorrhizal fungus typically found in a complex soil community of mycorrhizae, soil microbes, and host-tree roots referred to as the shiro in Japan. A curious characteristic of the shiro is an assortment of small rock fragments that have been implicated as a direct source of minerals and trace elements for the fungus. In this study, we measured the mineral content of 14 samples of shiro soil containing live matsutake mycelium and the extent to which the fungus can absorb minerals directly from the rock fragments. X-ray powder diffraction identified major phases of quartz, microcline, orthoclase, and albite in all shiro samples. PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting and direct sequencing confirmed the presence of T. matsutake on 32 of 33 rock fragments. Piloderma sp. co-occurred on 40% of fragments and was positively correlated with locations known to produce good mushroom crops. The ability of T. matsutake to absorb trace elements directly from rock fragments was examined in vitro on nutrient-agar plates supplemented with rock fragments from the shiro. In comparison to the mineral content of tissues grown on control media, the concentration of Al, Cu, Fe, Mn, P, and Zn increased from 1.1 to 106.4 times for both T. matsutake and Piloderma sp. Mineral content of dried sporocarps sampled from the study site partially reflected the results of the in vitro study. We discuss the implications of our results with respect to the natural development and artificial culture of this important fungus.

  2. The effects of copper, manganese and zinc on plant growth and elemental accumulation in the manganese-hyperaccumulator Phytolacca americana.

    PubMed

    Zhao, Huijun; Wu, Liangqi; Chai, Tuanyao; Zhang, Yuxiu; Tan, Jinjuan; Ma, Shengwen

    2012-09-01

    Synchrotron radiation X-ray fluorescence (SRXRF) and inductively coupled plasma mass spectrometry were used to estimate major, minor and trace elements in Cu-, Zn- and Mn-treated Phytolacca americana. The effects of the addition of Cu, Zn and Mn on morphological parameters, such as root length, shoot height, and fresh and dry weights of shoots and roots, were also examined. In addition, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases (GPX) and catalase (CAT) and the expression of Fe-SOD, Cu/Zn-SOD, metallothionein-2 and glutathione S-transferase (GST) exposed to the highest amounts of Cu, Zn or Mn were detected. Our results confirmed the following: (1) Zn supplementation leads to chlorosis, disturbed elemental homeostasis and decreased concentrations of micro- and macroelements such as Fe, Mg, Mn, Ca and K. Cu competed with Fe, Mn and Zn uptake in plants supplemented with 25 μM Cu. However, no antagonistic interactions took place between Cu, Zn, Mn and Fe uptake in plants supplemented with 100 μM Cu. Mn supplementation at various concentrations had no negative effects on elemental deficits. Mn was co-located with high concentrations of Fe and Zn in mature leaves and the concentrations of macro elements were unchanged. (2) P. americana supplemented with increased concentrations of Zn and Cu exhibited lower biomass production and reduced plant growth. (3) When plants were supplemented with the highest Zn and Cu concentrations, symptoms of toxicity corresponded to decreased SOD or CAT activities and increased APX and GPX activities. However, Mn tolerance corresponded to increased SOD and CAT activities and decreased POD and APX activities. Our study revealed that heavy metals partially exert toxicity by disturbing the nutrient balance and modifying enzyme activities that induce damage in plants. However, P. americana has evolved hyper accumulating mechanisms to maintain elemental balance and redox homeostasis under

  3. The effects of copper, manganese and zinc on plant growth and elemental accumulation in the manganese-hyperaccumulator Phytolacca americana.

    PubMed

    Zhao, Huijun; Wu, Liangqi; Chai, Tuanyao; Zhang, Yuxiu; Tan, Jinjuan; Ma, Shengwen

    2012-09-01

    Synchrotron radiation X-ray fluorescence (SRXRF) and inductively coupled plasma mass spectrometry were used to estimate major, minor and trace elements in Cu-, Zn- and Mn-treated Phytolacca americana. The effects of the addition of Cu, Zn and Mn on morphological parameters, such as root length, shoot height, and fresh and dry weights of shoots and roots, were also examined. In addition, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases (GPX) and catalase (CAT) and the expression of Fe-SOD, Cu/Zn-SOD, metallothionein-2 and glutathione S-transferase (GST) exposed to the highest amounts of Cu, Zn or Mn were detected. Our results confirmed the following: (1) Zn supplementation leads to chlorosis, disturbed elemental homeostasis and decreased concentrations of micro- and macroelements such as Fe, Mg, Mn, Ca and K. Cu competed with Fe, Mn and Zn uptake in plants supplemented with 25 μM Cu. However, no antagonistic interactions took place between Cu, Zn, Mn and Fe uptake in plants supplemented with 100 μM Cu. Mn supplementation at various concentrations had no negative effects on elemental deficits. Mn was co-located with high concentrations of Fe and Zn in mature leaves and the concentrations of macro elements were unchanged. (2) P. americana supplemented with increased concentrations of Zn and Cu exhibited lower biomass production and reduced plant growth. (3) When plants were supplemented with the highest Zn and Cu concentrations, symptoms of toxicity corresponded to decreased SOD or CAT activities and increased APX and GPX activities. However, Mn tolerance corresponded to increased SOD and CAT activities and decreased POD and APX activities. Our study revealed that heavy metals partially exert toxicity by disturbing the nutrient balance and modifying enzyme activities that induce damage in plants. However, P. americana has evolved hyper accumulating mechanisms to maintain elemental balance and redox homeostasis under

  4. Traffic-related trace element accumulation in roadside soils and wild grasses in the Qinghai-Tibet Plateau, China.

    PubMed

    Wang, Guanxing; Yan, Xuedong; Zhang, Fan; Zeng, Chen; Gao, Dan

    2013-12-30

    This research examines traffic-source trace elements accumulations and distributions in roadside soils and wild grasses in the Qinghai-Tibet Plateau. A total of 100 soil samples and 100 grass samples including Achnatherum splendens, Anaphalis nepalensis, Artemisia sphaerocephala, Carex moorcroftii, Iris lacteal, Kobresia myosuroides, Oreosolen wattii, Oxytropis ochrocephala and Stellera chamaejasme were collected at 100 sites from different road segments. The contents of metals and metalloids, including Cu, Zn, Cd, Pb, Cr, Co, Ni and As, in the soil and grass samples were analyzed using ICP-MS. The total mean concentrations of the eight trace elements in soils are Cu (22.84 mg/kg), Zn (100.56 mg/kg), Cd (0.28 mg/kg), Pb (28.75 mg/kg), Cr (36.82 mg/kg), Co (10.24 mg/kg), Ni (32.44 mg/kg) and As (21.43 mg/kg), while in grasses are Cu (9.85 mg/kg), Zn (31.47 mg/kg), Cd (0.05 mg/kg), Pb (2.06 mg/kg), Cr (14.16 mg/kg), Co (0.55 mg/kg), Ni (4.03 mg/kg) and As (1.33 mg/kg). The metal and metalloid concentrations in the nine grass species were all below the critical values of hyperaccumulators. The mean values and Multivariate Analysis of Variance (MANOVA) results indicate that: (1) the concentrations of the trace elements in the soils are higher than those in the grasses, (2) the concentrations of Cu, Zn, Cd, Pb in the soils decrease as the roadside distance increases, (3) the concentrations of trace elements in the grasses are the highest at 10 m from the road edge, (4) the higher the traffic volume, the higher the concentrations of the trace elements in the roadside soils and grasses, and (5) when the land cover is meadow, the lower the sand content in the soil, the lower the trace element concentrations. With a trace element's bioavailability represented by its transfer factor (TF) from the soil to the grass, the TFs of the eight trace elements are not in the same orders for different grass species.

  5. Platinum-group elements in southern Africa: mineral inventory and an assessment of undiscovered mineral resources: Chapter Q in Global mineral resource assessment

    USGS Publications Warehouse

    Zientek, Michael L.; Causey, J. Douglas; Parks, Heather L.; Miller, Robert J.

    2014-01-01

    The large layered intrusions in southern Africa—the Bushveld Complex and the Great Dyke—are now and will continue to be a major source of the world’s supply of PGE. Mining will not deplete the identified mineral resources and reserves or potential undiscovered mineral resources for many decades; however, in the near-term, PGE supply could be affected by social, environmental, political, and economic factors.

  6. Assessment of metallic mineral resources in the Humboldt River Basin, Northern Nevada, with a section on Platinum-Group-Element (PGE) Potential of the Humboldt Mafic Complex

    USGS Publications Warehouse

    Wallace, Alan R.; Ludington, Steve; Mihalasky, Mark J.; Peters, Stephen G.; Theodore, Ted G.; Ponce, David A.; John, David A.; and Berger, Byron R.; Zientek, Michael L.; Sidder, Gary B.; Zierenberg, Robert A.

    2004-01-01

    The Humboldt River Basin is an arid to semiarid, internally drained basin that covers approximately 43,000 km2 in northern Nevada. The basin contains a wide variety of metallic and nonmetallic mineral deposits and occurrences, and, at various times, the area has been one of the Nation's leading or important producers of gold, silver, copper, mercury, and tungsten. Nevada currently (2003) is the third largest producer of gold in the world and the largest producer of silver in the United States. Current exploration for additional mineral deposits focuses on many areas in northern Nevada, including the Humboldt River Basin.

  7. Reappraising Accretion to Vesta and the Angrite Parent Body Through Mineral-Scale Platinum Group Element and Os-Isotope Analyses

    NASA Astrophysics Data System (ADS)

    Riches, A. J. V.; Burton, K. W.; Nowell, G. M.; Dale, C. W.; Ottley, C. J.

    2016-08-01

    New methods presented here enable quantitative determination of mineral-scale PGE-abundances and Os-isotope compositions in meteorite materials thereby providing valuable new insight into planetary evolution.

  8. Transmission Electron Microscope Study of Platinum Group Element-Rich Micronuggets from Two Spherule Layer Intersections, Barberton Greenstone Belt, South Africa

    NASA Astrophysics Data System (ADS)

    Mohr-Westheide, T.; Greshake, A.; Wirth, R.; Reimold, W. U.; Fritz, J.

    2016-08-01

    New results of a comprehensive transmission electron microscope (TEM) study including microstructural and chemical analyses of three submicrometer sized, primary PGE metal nuggets in Archean spherule layer material from the Barberton Mountain Land.

  9. Study on separation of platinum group metals from high level liquid waste using macroporous (MOTDGA-TOA)/SiO{sub 2}-P silica-based absorbent

    SciTech Connect

    Ito, Tatsuya; Kim, Seong-Yun; Xu, Yuanlai; Hitomi, Keitaro; Ishii, Keizo; Nagaishi, Ryuji; Kimura, Takaumi

    2013-07-01

    The recovery of platinum group metals (PGMs) from high level liquid waste (HLLW) by macroporous silica-based adsorbent, (MOTDGA-TOA)/SiO{sub 2}-P has been developed by impregnating two extractants of N,N'-dimethyl-N,N'-di-n-octyl-thio-diglycolamide (MOTDGA) and tri-n-octylamine (TOA) into a silica/polymer composite support (SiO{sub 2}-P). The adsorption of Ru(III), Rh(III) and Pd(II) have been investigated in simulated HLLW by batch method. The adsorbent has shown good uptake property for Pd(II). In addition, the combined use of MOTDGA and TOA improved the adsorption of Ru(III) and Rh(III) better than the individual use of them. The usability of adsorbent in radiation fields was further confirmed by irradiation experiments. The adsorbent remained to have the uptake capability for PGMs over the absorbed dose of 100 kGy, corresponding with one really adsorbed by the adsorbent, and showed good retention capability for Pd(II) even at the absorbed dose of 800 kGy. The chromatographic separation of metal ions was demonstrated with the adsorbent packed column, there is no influence of Re(VII) (instead of Tc) on the excellent separation behavior of Pd(II). (authors)

  10. Levels of platinum group metals in selected species (Sarotherodon melanotheron, Chonophorus lateristriga, Macrobrachium vollenhovenii and Crassostrea tulipa) in some estuaries and lagoons along the coast of Ghana.

    PubMed

    Essumang, D K; Adokoh, C K; Boamponsem, L

    2010-10-12

    The use of some biota as bioindicators of heavy metal pollution has been demonstrated as particularly adequate due to their capacity of bioconcentration. This study evaluated the levels of platinum group metals (PGMs) in some selected species along the coastal belt of Ghana, using the neutron activation analysis (NAA) method. The result was processed to evaluate pollution indices in order to map the distribution of the metals in those species in the lagoons and estuaries along the costal belt of Ghana. The analysis showed significant levels of all PGMs in blackchin tilapia (Sarotherodon melanotheron Cichlidae), brown goby (Chonophorus lateristriga Gobiidae), shrimp (Macrobrachium vollenhovenii Palaemonidae), and mangrove oysters (Crassostrea tulipa Ostreidae) in the lagoons and river Pra estuary. However, the oysters showed an elevated mean concentration of 0.13 μg/g (dry weight) Pd. From the pollution indices, most of the sampling sites registered mean contamination factor (CF) values between 1.20 and 3.00 for Pt, Pd, and Rh. The pollution load index (PLI) conducted also gave an average pollution index between 0.79 and 2.37, indicating progressive contamination levels. The results revealed that anthropogenic sources, industrial and hospital effluent, etc., together with vehicular emissions, could be the contributing factors to the deposition of PGMs along the Ghanaian coast.

  11. Universal dependence of hydrogen oxidation and evolution reaction activity of platinum-group metals on pH and hydrogen binding energy

    PubMed Central

    Zheng, Jie; Sheng, Wenchao; Zhuang, Zhongbin; Xu, Bingjun; Yan, Yushan

    2016-01-01

    Understanding how pH affects the activity of hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is key to developing active, stable, and affordable HOR/HER catalysts for hydroxide exchange membrane fuel cells and electrolyzers. A common linear correlation between hydrogen binding energy (HBE) and pH is observed for four supported platinum-group metal catalysts (Pt/C, Ir/C, Pd/C, and Rh/C) over a broad pH range (0 to 13), suggesting that the pH dependence of HBE is metal-independent. A universal correlation between exchange current density and HBE is also observed on the four metals, indicating that they may share the same elementary steps and rate-determining steps and that the HBE is the dominant descriptor for HOR/HER activities. The onset potential of CO stripping on the four metals decreases with pH, indicating a stronger OH adsorption, which provides evidence against the promoting effect of adsorbed OH on HOR/HER. PMID:27034988

  12. Universal dependence of hydrogen oxidation and evolution reaction activity of platinum-group metals on pH and hydrogen binding energy.

    PubMed

    Zheng, Jie; Sheng, Wenchao; Zhuang, Zhongbin; Xu, Bingjun; Yan, Yushan

    2016-03-01

    Understanding how pH affects the activity of hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is key to developing active, stable, and affordable HOR/HER catalysts for hydroxide exchange membrane fuel cells and electrolyzers. A common linear correlation between hydrogen binding energy (HBE) and pH is observed for four supported platinum-group metal catalysts (Pt/C, Ir/C, Pd/C, and Rh/C) over a broad pH range (0 to 13), suggesting that the pH dependence of HBE is metal-independent. A universal correlation between exchange current density and HBE is also observed on the four metals, indicating that they may share the same elementary steps and rate-determining steps and that the HBE is the dominant descriptor for HOR/HER activities. The onset potential of CO stripping on the four metals decreases with pH, indicating a stronger OH adsorption, which provides evidence against the promoting effect of adsorbed OH on HOR/HER.

  13. Universal dependence of hydrogen oxidation and evolution reaction activity of platinum-group metals on pH and hydrogen binding energy.

    PubMed

    Zheng, Jie; Sheng, Wenchao; Zhuang, Zhongbin; Xu, Bingjun; Yan, Yushan

    2016-03-01

    Understanding how pH affects the activity of hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is key to developing active, stable, and affordable HOR/HER catalysts for hydroxide exchange membrane fuel cells and electrolyzers. A common linear correlation between hydrogen binding energy (HBE) and pH is observed for four supported platinum-group metal catalysts (Pt/C, Ir/C, Pd/C, and Rh/C) over a broad pH range (0 to 13), suggesting that the pH dependence of HBE is metal-independent. A universal correlation between exchange current density and HBE is also observed on the four metals, indicating that they may share the same elementary steps and rate-determining steps and that the HBE is the dominant descriptor for HOR/HER activities. The onset potential of CO stripping on the four metals decreases with pH, indicating a stronger OH adsorption, which provides evidence against the promoting effect of adsorbed OH on HOR/HER. PMID:27034988

  14. Traffic-Related Trace Element Accumulation in Roadside Soils and Wild Grasses in the Qinghai-Tibet Plateau, China

    PubMed Central

    Wang, Guanxing; Yan, Xuedong; Zhang, Fan; Zeng, Chen; Gao, Dan

    2013-01-01

    This research examines traffic-source trace elements accumulations and distributions in roadside soils and wild grasses in the Qinghai-Tibet Plateau. A total of 100 soil samples and 100 grass samples including Achnatherum splendens, Anaphalis nepalensis, Artemisia sphaerocephala, Carex moorcroftii, Iris lacteal, Kobresia myosuroides, Oreosolen wattii, Oxytropis ochrocephala and Stellera chamaejasme were collected at 100 sites from different road segments. The contents of metals and metalloids, including Cu, Zn, Cd, Pb, Cr, Co, Ni and As, in the soil and grass samples were analyzed using ICP-MS. The total mean concentrations of the eight trace elements in soils are Cu (22.84 mg/kg), Zn (100.56 mg/kg), Cd (0.28 mg/kg), Pb (28.75 mg/kg), Cr (36.82 mg/kg), Co (10.24 mg/kg), Ni (32.44 mg/kg) and As (21.43 mg/kg), while in grasses are Cu (9.85 mg/kg), Zn (31.47 mg/kg), Cd (0.05 mg/kg), Pb (2.06 mg/kg), Cr (14.16 mg/kg), Co (0.55 mg/kg), Ni (4.03 mg/kg) and As (1.33 mg/kg). The metal and metalloid concentrations in the nine grass species were all below the critical values of hyperaccumulators. The mean values and Multivariate Analysis of Variance (MANOVA) results indicate that: (1) the concentrations of the trace elements in the soils are higher than those in the grasses, (2) the concentrations of Cu, Zn, Cd, Pb in the soils decrease as the roadside distance increases, (3) the concentrations of trace elements in the grasses are the highest at 10 m from the road edge, (4) the higher the traffic volume, the higher the concentrations of the trace elements in the roadside soils and grasses, and (5) when the land cover is meadow, the lower the sand content in the soil, the lower the trace element concentrations. With a trace element’s bioavailability represented by its transfer factor (TF) from the soil to the grass, the TFs of the eight trace elements are not in the same orders for different grass species. PMID:24380977

  15. Element accumulation patterns of deciduous and evergreen tree seedlings on acid soils: implications for sensitivity to manganese toxicity.

    PubMed

    St Clair, Samuel B; Lynch, Jonathan P

    2005-01-01

    Foliar nutrient imbalances, including the hyperaccumulation of manganese (Mn), are correlated with symptoms of declining health in sensitive tree species growing on acidic forest soils. The objectives of this study were to: (1) compare foliar nutrient accumulation patterns of six deciduous (sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.), red oak (Quercus rubra L.), white oak (Quercus alba L.), black cherry (Prunus serotina Ehrh.) and white ash (Fraxinus americana L.)) and three evergreen (eastern hemlock (Tsuga canadensis L.), white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss.)) tree species growing on acidic forest soils; and (2) examine how leaf phenology and other traits that distinguish evergreen and deciduous tree species influence foliar Mn accumulation rates and sensitivity to excess Mn. For the first objective, leaf samples of seedlings from five acidic, non-glaciated field sites on Pennsylvania's Allegheny Plateau were collected and analyzed for leaf element concentrations. In a second study, we examined growth and photosynthetic responses of seedlings exposed to excess Mn in sand culture. In field samples, Mn in deciduous foliage hyperaccumulated to concentrations more than twice as high as those found in evergreen needles. Among species, sugar maple was the most sensitive to excess Mn based on growth and photosynthetic measurements. Photosynthesis in red maple and red oak was also sensitive to excess Mn, whereas white oak, black cherry, white ash and the three evergreen species were tolerant of excess Mn. Among the nine species, relative rates of photosynthesis were negatively correlated with foliar Mn concentrations, suggesting that photosynthetic sensitivity to Mn is a function of its rate of accumulation in seedling foliage. PMID:15519989

  16. Element accumulation patterns of deciduous and evergreen tree seedlings on acid soils: implications for sensitivity to manganese toxicity.

    PubMed

    St Clair, Samuel B; Lynch, Jonathan P

    2005-01-01

    Foliar nutrient imbalances, including the hyperaccumulation of manganese (Mn), are correlated with symptoms of declining health in sensitive tree species growing on acidic forest soils. The objectives of this study were to: (1) compare foliar nutrient accumulation patterns of six deciduous (sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.), red oak (Quercus rubra L.), white oak (Quercus alba L.), black cherry (Prunus serotina Ehrh.) and white ash (Fraxinus americana L.)) and three evergreen (eastern hemlock (Tsuga canadensis L.), white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss.)) tree species growing on acidic forest soils; and (2) examine how leaf phenology and other traits that distinguish evergreen and deciduous tree species influence foliar Mn accumulation rates and sensitivity to excess Mn. For the first objective, leaf samples of seedlings from five acidic, non-glaciated field sites on Pennsylvania's Allegheny Plateau were collected and analyzed for leaf element concentrations. In a second study, we examined growth and photosynthetic responses of seedlings exposed to excess Mn in sand culture. In field samples, Mn in deciduous foliage hyperaccumulated to concentrations more than twice as high as those found in evergreen needles. Among species, sugar maple was the most sensitive to excess Mn based on growth and photosynthetic measurements. Photosynthesis in red maple and red oak was also sensitive to excess Mn, whereas white oak, black cherry, white ash and the three evergreen species were tolerant of excess Mn. Among the nine species, relative rates of photosynthesis were negatively correlated with foliar Mn concentrations, suggesting that photosynthetic sensitivity to Mn is a function of its rate of accumulation in seedling foliage.

  17. Accumulation and Translocation of Essential and Nonessential Elements by Tomato Plants (Solanum lycopersicum) Cultivated in Open-Air Plots under Organic or Conventional Farming Techniques.

    PubMed

    Liñero, Olaia; Cidad, Maite; Carrero, Jose Antonio; Nguyen, Christophe; de Diego, Alberto

    2015-11-01

    A 5-month experiment was performed to study the accumulation of several inorganic elements in tomato plants cultivated using organic or synthetic fertilizer. Plants were harvested in triplicate at six sampling dates during their life cycle. Statistical and chemometric analysis of data indicated the sequestration of toxic elements and of Na, Zn, Fe, and Co in roots, while the rest of the elements, including Cd, were mainly translocated to aboveground organs. A general decreasing trend in element concentrations with time was observed for most of them. A negative correlation between some element concentrations and ripening stage of fruits was identified. Conventionally grown plants seemed to accumulate more Cd and Tl in their tissues, while organic ones were richer in some nutrients. However, there was no clear effect of the fertilizer used (organic vs synthetic) on the elemental composition of fruits.

  18. Accumulation and Translocation of Essential and Nonessential Elements by Tomato Plants (Solanum lycopersicum) Cultivated in Open-Air Plots under Organic or Conventional Farming Techniques.

    PubMed

    Liñero, Olaia; Cidad, Maite; Carrero, Jose Antonio; Nguyen, Christophe; de Diego, Alberto

    2015-11-01

    A 5-month experiment was performed to study the accumulation of several inorganic elements in tomato plants cultivated using organic or synthetic fertilizer. Plants were harvested in triplicate at six sampling dates during their life cycle. Statistical and chemometric analysis of data indicated the sequestration of toxic elements and of Na, Zn, Fe, and Co in roots, while the rest of the elements, including Cd, were mainly translocated to aboveground organs. A general decreasing trend in element concentrations with time was observed for most of them. A negative correlation between some element concentrations and ripening stage of fruits was identified. Conventionally grown plants seemed to accumulate more Cd and Tl in their tissues, while organic ones were richer in some nutrients. However, there was no clear effect of the fertilizer used (organic vs synthetic) on the elemental composition of fruits. PMID:26457684

  19. The accumulation of elements in plants growing spontaneously on small heaps left by the historical Zn-Pb ore mining.

    PubMed

    Stefanowicz, Anna M; Stanek, Małgorzata; Woch, Marcin W; Kapusta, Paweł

    2016-04-01

    The study evaluated the levels of nine metals, namely Ca, Cd, Fe, K, Mg, Mn, Pb, Tl, and Zn, in soils and tissues of ten plant species growing spontaneously on heaps left by historical mining for Zn-Pb ores. The concentrations of Cd, Pb, Tl, and Zn in heap soils were much higher than in control soils. Plants growing on heaps accumulated excessive amounts of these elements in tissues, on average 1.3-52 mg Cd kg(-1), 9.4-254 mg Pb kg(-1), 0.06-23 mg Tl kg(-1) and 134-1479 mg Zn kg(-1) in comparison to 0.5-1.1 mg Cd kg(-1), 2.1-11 mg Pb kg(-1), 0.02-0.06 mg Tl kg(-1), and 23-124 mg Zn kg(-1) in control plants. The highest concentrations of Cd, Pb, and Zn were found in the roots of Euphorbia cyparissias, Fragaria vesca, and Potentilla arenaria, and Tl in Plantago lanceolata. Many species growing on heaps were enriched in K and Mg, and depleted in Ca, Fe, and Mn. The concentrations of all elements in plant tissues were dependent on species, organ (root vs. shoot), and species-organ interactions. Average concentrations of Ca, K, and Mg were generally higher in shoots than in roots or similar in the two organs, whereas Cd, Fe, Pb, Tl, and Zn were accumulated predominantly in the roots. Our results imply that heaps left by historical mining for Zn-Pb ores may pose a potential threat to the environment and human health. PMID:26635220

  20. Element accumulation in boreal bryophytes, lichens and vascular plants exposed to heavy metal and sulfur deposition in Finland.

    PubMed

    Salemaa, Maija; Derome, John; Helmisaari, Heljä-Sisko; Nieminen, Tiina; Vanha-Majamaa, Ilkka

    2004-05-25

    Macronutrient (N, P, K, Mg, S, Ca), heavy metal (Fe, Zn, Mn, Cu, Ni, Cd, Pb) and Al concentrations in understorey bryophytes, lichens and vascular plant species growing in Scots pine forests at four distances from the Harjavalta Cu-Ni smelter (0.5, 2, 4 and 8 km) were compared to those at two background sites in Finland. The aim was to study the relationship between element accumulation and the distribution of the species along a pollution gradient. Elevated sulfur, nitrogen and heavy metal concentrations were found in all species groups near the pollution source. Macronutrient concentrations tended to decrease in the order: vascular plants>bryophytes>lichens, when all the species groups grew on the same plot. Heavy metal concentrations (except Mn) were the highest in bryophytes, followed by lichens, and were the lowest in vascular plants. In general, vascular plants, being capable of restricting the uptake of toxic elements, grew closer to the smelter than lichens, while bryophytes began to increase in the understorey vegetation at further distances from the smelter. A pioneer moss (Pohlia nutans) was an exception, because it accumulated considerably higher amounts of Cu and Ni than the other species and still survived close to the smelter. The abundance of most of the species decreased with increasing Cu and Ni concentrations in their tissues. Cetraria islandica, instead, showed a positive relationship between the abundance and Cu, Ni and S concentrations of the thallus. It is probable that, in addition to heavy metals, sporadically high SO(2) emissions have also affected the distribution of the plant species.

  1. Accumulation of nutrients in soils affected by perennial colonies of piscivorous birds with reference to biogeochemical cycles of elements.

    PubMed

    Ligeza, Slawomir; Smal, Halina

    2003-07-01

    The accumulation of selected N, K, and P forms in soils within three perennial colonies of black cormorant (Phalacrocorax carbo sinensis) and grey heron (Ardea cinerea) located in northern and eastern Poland were investigated. Soil samples were collected beneath the nests from the most representative for each colony plots. Control samples were taken outside the colonies within sites adjacent to the nesting areas but not affected by bird excrement. From each genetic horizon (20 horizons) in soil profiles, a cumulative sample of about 25-30 kg of soil was taken for analysis. Nitrogen by Kjeldahl, ammonium ions (N(NH(4))), nitrates (N(NO(3))), exchangeable potassium (K(ex)), available potassium (K(av)), and available phosphorus (P(av)) were determined. The soils affected by birds demonstrated a very strong enrichment with N, K, and P in comparison to the control sites, especially in the topsoil horizons. The content of N(NH(4)) in individual soil horizons from the colonies was from 1.7 to 10.1 times higher than the respective control, N(NO(3)) from 2.9 to 215.7, K(ex) from 2.0 to 35.1, K(av) from 1.1 to 48.1, and P(av) in the range from 2.4 to 53.0 times. The highest increment of chemical elements was noticeable in the soils of territories inhabited by cormorants and the least in forest occupied by herons. Some relationships between soil texture and accumulation of biogenic nutrients were determined. Clay loam soil showed the greatest enrichment with analysed forms of elements with the exception of N(NH(4)).

  2. Surface disposal of produced waters in western and southwestern Pennsylvania: potential for accumulation of alkali-earth elements in sediments

    USGS Publications Warehouse

    Skalak, Katherine J.; Engle, Mark A.; Rowan, Elisabeth L.; Jolly, Glenn D.; Conko, Kathryn M.; Benthem, Adam J.; Kraemer, Thomas F.

    2014-01-01

    Waters co-produced with hydrocarbons in the Appalachian Basin are of notably poor quality (concentrations of total dissolved solids (TDS) and total radium up to and exceeding 300,000 mg/L and 10,000 pCi/L, respectively). Since 2008, a rapid increase in Marcellus Shale gas production has led to a commensurate rise in associated wastewater while generation of produced water from conventional oil and gas activities has continued. In this study, we assess whether disposal practices from treatment of produced waters from both shale gas and conventional operations in Pennsylvania could result in the accumulation of associated alkali earth elements. The results from our 5 study sites indicate that there was no increase in concentrations of total Ra (Ra-226) and extractable Ba, Ca, Na, or Sr in fluvial sediments downstream of the discharge outfalls (p > 0.05) of publicly owned treatment works (POTWs) and centralized waste treatment facilities (CWTs). However, the use of road spreading of brines from conventional oil and gas wells for deicing resulted in accumulation of Ra-226 (1.2 ×), and extractable Sr (3.0 ×), Ca (5.3 ×), and Na (6.2 ×) in soil and sediment proximal to roads (p < 0.05). Although this study is an important initial assessment of the impacts of these disposal practices, more work is needed to consider the environmental consequences of produced waters management.

  3. Differential patterns of accumulation and retention of dietary trace elements associated with coal ash during larval development and metamorphosis of an amphibian.

    PubMed

    Heyes, Andrew; Rowe, Christopher L; Conrad, Phillip

    2014-01-01

    We performed an experiment in which larval gray tree frogs (Hyla chrysoscelis) were raised through metamorphosis on diets increased with a suite of elements associated with coal combustion residues (silver [Ag], arsenic [As], cadmium [Cd], chromium [Cr], copper [Cu], mercury [Hg], lead [Pb], selenium [Se], vanadium [V], and zinc [Zn]) at "low" and "high" concentrations. We quantified accumulation of metals at three life stages (mid-larval development, initiation of metamorphosis, and completion of metamorphosis) as well as effects on survival, metabolic rate, size at metamorphosis, and duration and loss of weight during metamorphosis. Most elements were accumulated in a dose-dependent pattern by some or all life stages, although this was not the case for Hg. For most elements, larval body burdens exceeded those of later life stages in some or all treatments (control, low, or high). However for Se, As, and Hg, body burdens in control and low concentrations were increased in later compared with earlier life stages. A lack of dose-dependent accumulation of Hg suggests that the presence of high concentrations of other elements (possibly Se) either inhibited accumulation or increased depuration of Hg. The duration of metamorphosis (forelimb emergence through tail resorption) was lengthened in individuals exposed to the highest concentrations of elements, but there were no other statistically significant biological effects. This study shows that patterns of accumulation and possibly depuration of metals and trace elements are complex in animals possessing complex life cycles. Further study is required to determine specific interactions affecting these patterns, in particular which elements may be responsible for affecting accumulation or retention of Hg when organisms are exposed to complex mixtures of elements. PMID:24169791

  4. Differential patterns of accumulation and retention of dietary trace elements associated with coal ash during larval development and metamorphosis of an amphibian.

    PubMed

    Heyes, Andrew; Rowe, Christopher L; Conrad, Phillip

    2014-01-01

    We performed an experiment in which larval gray tree frogs (Hyla chrysoscelis) were raised through metamorphosis on diets increased with a suite of elements associated with coal combustion residues (silver [Ag], arsenic [As], cadmium [Cd], chromium [Cr], copper [Cu], mercury [Hg], lead [Pb], selenium [Se], vanadium [V], and zinc [Zn]) at "low" and "high" concentrations. We quantified accumulation of metals at three life stages (mid-larval development, initiation of metamorphosis, and completion of metamorphosis) as well as effects on survival, metabolic rate, size at metamorphosis, and duration and loss of weight during metamorphosis. Most elements were accumulated in a dose-dependent pattern by some or all life stages, although this was not the case for Hg. For most elements, larval body burdens exceeded those of later life stages in some or all treatments (control, low, or high). However for Se, As, and Hg, body burdens in control and low concentrations were increased in later compared with earlier life stages. A lack of dose-dependent accumulation of Hg suggests that the presence of high concentrations of other elements (possibly Se) either inhibited accumulation or increased depuration of Hg. The duration of metamorphosis (forelimb emergence through tail resorption) was lengthened in individuals exposed to the highest concentrations of elements, but there were no other statistically significant biological effects. This study shows that patterns of accumulation and possibly depuration of metals and trace elements are complex in animals possessing complex life cycles. Further study is required to determine specific interactions affecting these patterns, in particular which elements may be responsible for affecting accumulation or retention of Hg when organisms are exposed to complex mixtures of elements.

  5. The spatial distribution, accumulation and potential source of seldom monitored trace elements in sediments of Three Gorges Reservoir, China

    PubMed Central

    Han, Lanfang; Gao, Bo; Zhou, Huaidong; Xu, Dongyu; Wei, Xin; Gao, Li

    2015-01-01

    The alteration of hydrologic condition of Three Gorges Reservoir (TGR) after impoundment has caused numerous environmental changes. This study investigated the distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs) in sediments from three tributaries (ZY, MX and CT) and one mainstream (CJ) in TGR during different seasons. The average contents of most SMTEs excluding Sb in the winter were similar to that in the summer. For Sb, its average concentrations in the summer and winter were roughly six and three times higher than its background value, respectively. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediments were obviously contaminated by Sb. The enrichment factors (EF) of Ga and Sb were higher than 2.0, revealing the possible anthropogenic inputs; However, the EFs of other SMTEs were lower than 1.5, indicating the natural inputs. Correlation and principal component analysis suggested the most SMTEs were positively correlated with major elements (Cr, Mn, Cu, Zn, As, Cd and Pb) and clay contents, which implies that SMTEs had the same sources with these major metals, and the fine particles might be a major carrier for transporting SMTEs from the rivers to the TGR. PMID:26538153

  6. Variation in trace-element accumulation in predatory fishes from a stream contaminated by coal combustion waste.

    PubMed

    Fletcher, Dean E; Lindell, Angela H; Stillings, Garrett K; Mills, Gary L; Blas, Susan A; McArthur, J Vaun

    2014-04-01

    Extensive and critical evaluation can be required to assess contaminant bioaccumulation in large predatory fishes. Species differences in habitat use, resource use, and trophic level, often influenced by body form, can result in diverging contaminant bioaccumulation patterns. Moreover, the broad size ranges inherent with large-bodied fish provide opportunity for trophic and habitat shifts within species that can further influence contaminant exposure. We compared contaminant bioaccumulation in four fish species, as well as two herbivorous invertebrates, from a coal combustion waste contaminated stream. Muscle, liver, and gonad tissue were analyzed from fish stratified across the broadest size ranges available. Effects of trophic position (δ (15)N), carbon sources (δ (13)C), and body size varied among and within species. Mercury and cesium concentrations were lowest in the invertebrates and increased with trophic level both among and within fish species. Other elements, such as vanadium, cadmium, barium, nickel, and lead, had greater levels in herbivorous invertebrates than in fish muscle. Sequestration by the fish livers averted accumulation in muscle. Consequently, fish liver tissue appeared to be a more sensitive indicator of bioavailability, but exceptions existed. Despite liver sequestration, within fishes, muscle concentrations of many elements still tended to increase by trophic level. Notable variation within some species was observed. These results illustrate the utility of stable isotope data in exploring differences of bioaccumulation within taxa. Our analyses suggest a need for further evaluation of the underlying sources of this variability to better understand contaminant bioaccumulation in large predatory fishes.

  7. The spatial distribution, accumulation and potential source of seldom monitored trace elements in sediments of Three Gorges Reservoir, China.

    PubMed

    Han, Lanfang; Gao, Bo; Zhou, Huaidong; Xu, Dongyu; Wei, Xin; Gao, Li

    2015-11-05

    The alteration of hydrologic condition of Three Gorges Reservoir (TGR) after impoundment has caused numerous environmental changes. This study investigated the distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs) in sediments from three tributaries (ZY, MX and CT) and one mainstream (CJ) in TGR during different seasons. The average contents of most SMTEs excluding Sb in the winter were similar to that in the summer. For Sb, its average concentrations in the summer and winter were roughly six and three times higher than its background value, respectively. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediments were obviously contaminated by Sb. The enrichment factors (EF) of Ga and Sb were higher than 2.0, revealing the possible anthropogenic inputs; However, the EFs of other SMTEs were lower than 1.5, indicating the natural inputs. Correlation and principal component analysis suggested the most SMTEs were positively correlated with major elements (Cr, Mn, Cu, Zn, As, Cd and Pb) and clay contents, which implies that SMTEs had the same sources with these major metals, and the fine particles might be a major carrier for transporting SMTEs from the rivers to the TGR.

  8. The spatial distribution, accumulation and potential source of seldom monitored trace elements in sediments of Three Gorges Reservoir, China.

    PubMed

    Han, Lanfang; Gao, Bo; Zhou, Huaidong; Xu, Dongyu; Wei, Xin; Gao, Li

    2015-01-01

    The alteration of hydrologic condition of Three Gorges Reservoir (TGR) after impoundment has caused numerous environmental changes. This study investigated the distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs) in sediments from three tributaries (ZY, MX and CT) and one mainstream (CJ) in TGR during different seasons. The average contents of most SMTEs excluding Sb in the winter were similar to that in the summer. For Sb, its average concentrations in the summer and winter were roughly six and three times higher than its background value, respectively. Contamination factor (CF) and geoaccumulation index (Igeo) demonstrated that most of the sediments were obviously contaminated by Sb. The enrichment factors (EF) of Ga and Sb were higher than 2.0, revealing the possible anthropogenic inputs; However, the EFs of other SMTEs were lower than 1.5, indicating the natural inputs. Correlation and principal component analysis suggested the most SMTEs were positively correlated with major elements (Cr, Mn, Cu, Zn, As, Cd and Pb) and clay contents, which implies that SMTEs had the same sources with these major metals, and the fine particles might be a major carrier for transporting SMTEs from the rivers to the TGR. PMID:26538153

  9. Trace element accumulation in the moss Hypnum cupressiforme Hedw. and the trees Quercus ilex L. and Pinus halepensis Mill. in Catalonia.

    PubMed

    Sardans, Jordi; Peñuelas, Josep

    2005-09-01

    We studied trace element accumulation in the moss Hypnum cupressiforme and the widely distributed Mediterranean trees Quercus ilex and Pinus halepensis located at increasing distances from the Barcelona Metropolitan Area. Hypnum cupressiforme, Quercus ilex and, to a somewhat lesser extent, Pinus halepensis, have proved to be adequate as possible accumulative monitoring species in relation to trace elements pollution. No significant effects of crown orientation were found. One-year old leaves generally accumulated more trace elements than current-year leaves. All the studied trace elements showed greatest concentrations in the Barcelona Metropolitan Area, with lead, cadmium and arsenic concentrations being especially high. In general, trace element concentrations in biomass were similar or higher than the values reported from other Mediterranean urban areas of Europe. The top soil-layer concentrations were also higher in the Barcelona Metropolitan Area indicating the existence of mechanisms of atmospheric deposition and/or concentration in the soil. The lower values of Pb of airborne origin relative to other elements such as Cd, Cu, Zn and Sb suggest that traffic exhausts are not the only important focus of pollutants in this area. The results of biomass concentrations and of enrichment factor of biomasses respect to bedrock and soils show that atmospheric inputs account for the higher trace element concentrations in the Barcelona Metropolitan Area.

  10. Accumulation of airborne trace elements in mosses, lichens and synthetic materials exposed at urban monitoring stations: towards a harmonisation of the moss-bag technique.

    PubMed

    Giordano, S; Adamo, P; Spagnuolo, V; Tretiach, M; Bargagli, R

    2013-01-01

    Mosses, lichens and cellulose filters were exposed for 17 weeks at four urban monitoring stations in Naples (S Italy) to assess the accumulation of airborne Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Ni, Pb, Ti, V, and Zn. In each site, the element accumulation was significantly higher in the moss Hypnum cupressiforme than in the lichen Pseudevernia furfuracea. Acid washed mosses accumulated the highest amount of trace elements, but the differences in element concentrations among the moss samples exposed after water washing and different devitalisation treatments (acid washing, oven drying and water boiling) and between the lichen samples exposed with and without the nylon bag were not statistically significant. The cellulose filters showed the lowest accumulation capability. The reciprocal ordination of sites and exposed materials showed an increasing contamination gradient (especially for Pb, Cu and Zn) from the background site to the trafficked city streets; this pattern was undetectable from PM(10) data recorded by the automatic monitoring devices operating in the four exposure sites. The element profile in exposed materials did not change substantially throughout the urban area and particles of polluted urban soils seem the main source of airborne metals in Naples. Through a comprehensive evaluation of the results from this and previous studies, a protocol is suggested for the moss-bag monitoring of trace element deposition in urban environments.

  11. Diverse accumulation and distribution of nutrient elements in developing wheat grain studied by laser ablation inductively coupled plasma mass spectrometry imaging.

    PubMed

    Wu, Bei; Andersch, Franka; Weschke, Winfriede; Weber, Hans; Becker, J Sabine

    2013-09-01

    The present study focused on the elemental distribution in the developing wheat grain by using the laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging technique. Our studies show that the embryo accumulated high concentrations of nutrient elements, such as Fe, K, Cu, and Zn, while Ca was accumulated in the bran of the wheat grain which might be attributed to its function of structural maintenance. In the endosperm the majority of the nutrients were located in the aleurone layer. Within the grain, the embryo could be considered as a nutrient pool for macro- and micro-elements essential for the development of the seedling. Elemental images showed that considerable amounts of nutrients were stored in the scutellum of the embryo, which might be related to the high gene expression of element transporters in the scutellum. Root primordia and leaf primordia were enriched in particular elements, such as Mn and Zn respectively. In total 34 cross sections were analyzed and used for generation of a sequence of elemental distribution images to demonstrate elemental changes along the perpendicular axis of the wheat grain embryo. Further development of three-dimensional modeling will be combined with physiological studies to better understand the mechanisms of elemental distribution and storage in the wheat grain. These studies will provide fundamental knowledge on improving the nutritional value and agronomic practices.

  12. The distribution, accumulation and potential source of seldom monitored trace elements in sediments of Beijiang River, South China.

    PubMed

    Gao, Bo; Lu, Jin; Zhou, Huai-Dong; Yin, Shu-Hua; Hao, Hong

    2012-01-01

    A geochemical study of Beijiang River sediments was carried out to analyze the concentrations, distribution, accumulation and potential sources of the seldom monitored trace elements (SMTEs: Sc, V, Co, Ga, Y, Sn and Sb). The mean concentrations of Sc, V, Co, Ga, Y, Sn and Sb were 8.2, 60.3, 9.6, 17.2, 28.6, 85.6 and 39.0 mg/kg, respectively. The concentrations of the SMTEs, together with their spatial distribution showed that the SMTEs were mainly due to anthropogenic inputs from the metal smelting industries and local mining activities in the upper region of the river. The assessment by geoaccumulation index indicates that Sc, V, Co, Ga and Y are at the unpolluted level, Sn is at the 'strongly contaminated' level, and Sb is at the 'extremely contaminated' level. The pollution level of the SMTEs is: Sb > Sn > Y > Ga > Co > V > Sc. The results of correlation analysis and principal component analysis indicated the Sn and Sb were positively correlated with each other, indicating a common source in sediments. In conclusion, our results indicate that the sediments in Beijiang River have been severely contaminated by Sn and Sb.

  13. Species classification and bioactive ingredients accumulation of BaiJiangCao based on characteristic inorganic elements analysis by inductively coupled plasma-mass spectrometry and multivariate analysis

    PubMed Central

    Wen-Lan, Li; Xue, Zhang; Xin-Xin, Yang; Shuai, Wang; Lin, Zhao; Huan-Jun, Zhao; Yong-Rui, Bao; Chen-Feng, Ji; Ning, Chen; Zheng, Xiang

    2015-01-01

    Background: Patrinia scabiosaefolia Fisch and Patrinia villosa (Thunb.) Juss., two species herbs with the same Chinese name “BaiJiangCao”, are important ancient herbal medicines widely used for more than 2000 years. The clinical application of two species herb is confused due to the difficult identification. Objective: The objective was to authenticate the species of BaiJiangCao and analyze the accumulation of bioactive ingredients based on characteristic inorganic elements analysis. Materials and Methods: Content of 32 inorganic elements in BaiJiangCao from different habitats were determined by inductively coupled plasma-mass spectrometry (ICP-MS), and the characteristic inorganic elements were picked to distinguish the species of the herb by principal component analysis and cluster analysis. Contents of two bioactive ingredients, luteoloside, and oleanolic acid, in the samples, were also analyzed by high-performance liquid chromatography method. Relationship between accumulation of bioactive ingredients and content of macroelements in BaiJiangCao was established by statistics. Results: A 4 macroelements (Na, Mg, K, Fe) in 32 determined inorganic elements were picked for characteristic inorganic elements. Content of Na, Mg, K and Fe showed positive correlations with that of luteoloside, content of Na, Mg showed positive correlations with that of oleanolic acid, but content of K and Fe showed negative correlations with that of oleanolic acid. Conclusion: It is for the first time to utilize the characteristic inorganic elements as an index to classify the herb species by the method of ICP-MS and multivariate analysis. And it is also the first report to investigate the influence of inorganic elements in herb on the accumulation of bioactive components which could affect the pharmacological efficacy of the herb medicine. And this method could also be utilized in research of corresponding aspects. PMID:26600721

  14. Accumulation of germanium and rare earth elements in functional groups of selected energy crops cultivated on two different soils

    NASA Astrophysics Data System (ADS)

    Wiche, Oliver; Székely, Balázs

    2016-04-01

    A field experiment was conducted to investigate the uptake of Ge and selected REEs in functional groups of selected crop species. Five species belonging to the functional group of grasses (Hordeum vulgare, Zea mays, Avena sativa, Panicum miliaceum and Phalaris arundinacea) and four species from the group of herbs (Lupinus albus, Lupinus angustifolius, Fagopyrum esculentum and Brassica napus) were cultivated in parallel on two soils with slightly alkaline (soil A: pH = 7.8) and slightly acidic (soil B: pH = 6.8) conditions. After harvest, concentrations of Ge, La, Nd, Gd, Er, P, Fe, Mn and Si in shoot tissues were determined with ICP-MS. Concentrations of Ge were significantly higher in grasses than in herbs. Conversely, concentrations of La and Nd were significantly higher in herbs, than in grasses. Highest concentrations were measured in Brassica napus (REEs) and Zea mays (Ge). Concentrations of Ge significantly correlated with that of Si in the shoots showing low concentrations in herbs and high concentrations in grasses, indicating a common mechanism during the uptake in grasses. Concentrations of REEs correlated significantly with that of Fe, indicating increasing concentrations of REEs with increasing concentrations of Fe. Cultivation of species on the slightly acidic soil significantly increased the uptake Ge in Lupinus albus and Phalaris arundinacea and the uptake of La and Nd in all species except of Phalaris arundinacea. This study demonstrated that commonly used field crops could be regarded as suitable candidates for a phytomining of Ge and REEs, since these species develop high yields of shoots, high concentrations of elements and are widely used in agricultural practice. Under soil conditions where bioavailability of Ge and REEs is expected to be low (soil A) accumulation can be estimated at 1.8 g/ha Ge in Z. mays and 3.7 g/ha REEs (1.5 g/ha La, 1.4 g/ha Nd, 0.6 g/ha Gd, 0.3 g/ha Er), respectively, in B. napus, assuming a constant high efficiency of

  15. Seasonal Variation in the Accumulation of Trace Elements and Contaminants in Five Shrimp Species from Iskenderun Bay and Their Consumibility as Human Food.

    PubMed

    Kaymacı, Sevtap; Altun, Beyza Ersoy

    2016-08-01

    Seasonal accumulation of trace elements and contaminants in the muscle tissue of five shrimp species; Speckled Shrimp, Deepwater Rose Shrimp, Red Shrimp, Grooved Shrimp and Green Tiger Shrimp, from Iskenderun Bay of Eastern Mediterranean Sea were investigated. It was observed the period of year for the accumulation of such elements is important. Results indicate that peaks are generally reached in autumn and in spring. The levels of Zn, Fe, Cu and Ni were the highest in autumn whereas the maximum Sn and Cr concentrations were obtained in spring. The levels of Cu and Zn were found to be within the permissible limits for human consumption. Contaminants were accumulated at the highest levels in autumn. Attention has to be drawn that Cd values were above permissible limits for deepwater pink shrimp caught in autumn and winter, and for green tiger shrimp caught in autumn. Besides, the accumulation of high level of Pb in the tissue of all species except grooved shrimp whose value was low in spring should also be considered as a warning signal.

  16. Seasonal Variation in the Accumulation of Trace Elements and Contaminants in Five Shrimp Species from Iskenderun Bay and Their Consumibility as Human Food.

    PubMed

    Kaymacı, Sevtap; Altun, Beyza Ersoy

    2016-08-01

    Seasonal accumulation of trace elements and contaminants in the muscle tissue of five shrimp species; Speckled Shrimp, Deepwater Rose Shrimp, Red Shrimp, Grooved Shrimp and Green Tiger Shrimp, from Iskenderun Bay of Eastern Mediterranean Sea were investigated. It was observed the period of year for the accumulation of such elements is important. Results indicate that peaks are generally reached in autumn and in spring. The levels of Zn, Fe, Cu and Ni were the highest in autumn whereas the maximum Sn and Cr concentrations were obtained in spring. The levels of Cu and Zn were found to be within the permissible limits for human consumption. Contaminants were accumulated at the highest levels in autumn. Attention has to be drawn that Cd values were above permissible limits for deepwater pink shrimp caught in autumn and winter, and for green tiger shrimp caught in autumn. Besides, the accumulation of high level of Pb in the tissue of all species except grooved shrimp whose value was low in spring should also be considered as a warning signal. PMID:27306878

  17. Environmental monitoring of the area surrounding oil wells in Val d'Agri (Italy): element accumulation in bovine and ovine organs.

    PubMed

    Miedico, Oto; Iammarino, Marco; Paglia, Giuseppe; Tarallo, Marina; Mangiacotti, Michele; Chiaravalle, A Eugenio

    2016-06-01

    In this work, environmental heavy metal contamination in the Val d'Agri area of Southern Italy was monitored, measuring the accumulation of 18 heavy metals (U, Hg, Pb, Cd, As, Sr, Sn, V, Ni, Cr, Mo, Co, Cu, Zn, Ca, Mn, Fe, and Al) in the organs of animals raised in the surrounding area (kidney, lung, and liver of bovine and ovine species). Val d'Agri features various oil processing centers which are potentially a significant source of environmental pollution, making it essential to perform studies that will outline the state of the art on which any recovery plans and interventions may be developed. The analysis was carried out using official and accredited analytical methods based on inductively coupled plasma mass spectrometry, and the measurements were statistically processed in order to give a contribution to risk assessment. Even though five samples showed Pb and Cd concentrations above the limits defined in the European Commission Regulation (EC) No 1881/2006, the mean concentrations of most elements suggest that contamination in this area is low. Consequently, these results also suggest that there is no particular risk for human exposure to toxic trace elements. Nevertheless, the findings of this work confirm that element accumulation in ovine species is correlated with geographical livestock area. Therefore, ovine-specific organs might be used as bioindicators for monitoring contamination by specific toxic elements in exposed areas. PMID:27165602

  18. Lead, platinum, and other heavy elements in the primary cosmic radiation: HEAO-3 results ssc wg032961 cb553097

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Binns, W. R.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.; Israel, M. H.; Klarmann, J.; Newport, B. J.; Stone, E. C.

    1985-01-01

    An observation of the abundances of cosmic-ray lead and platinum-group nuclei using data from the HEAO-3 Heavy Nuclei Experiment (HNE) which consisted of ion chambers mounted on both sides of a plastic Cerenkov counter is reported. Further analysis with more stringent selections, inclusion of additional data, and a calibration at the LBL Bevalac, have allowed obtaining the abundance ratio of lead and the platinum group of elements for particles that had a cutoff rigidity R sub c 5 GV.

  19. [Increased accumulation of some trace elements in peripheral blood and bile of patients infested with Opisthorchis felineus (Rivolta, 1884) and Metorchis bilis (Braun, 1890)].

    PubMed

    Il'inskikh, E N; Il'inskikh, I N; Il'inskikh, N N

    2009-01-01

    The invasion with Opisthorchis felineus (Rivolta, 1884) is known to be common in the Ob River region, West Siberia. These trematodes parasitize biliary tract of devinitive host (man or some species of animals). Other opisthorchiid species occurring in West Siberia, Metorchis bilis (Braun, 1890), has also been recorded recently as human parasite. Life cycles of both these trematodes include fish-eating mammal hosts. Eggs of O. felineus and M. bilis are very similar morphologically and can hardly be indentified. Chronic invasion with the helminthes is found to be a cause of disbolism of trace elements or high accumulation of some essential and toxic elements in the organism of definitive host. The aim of the present study was to determine concentrations of some essential and toxic elements in samples of peripheral blood and bile obtained from patients infested with Opisthorchis and/or Metorchis using instrumental neuron-activation technique. At first, all patients with microscopically confirmed opisthorchiasis (by microscopic examination of faeces and bile for the helminth eggs) were examined with serological method (ELISA) for specific anti-Opisthorchis and anti-Metorchis antibodies. Among 139 examined patients, 56.1% had specific antibodies against both Opisthorchis and Metorchis, 41.7% showed anti-Opisthorchis antibodies only, and 2.1% turn out to be seropositive for anti-Metorchis antibodies only. Of 31 elements detected in the samples of peripheral blood and bile, the concentration of nine essential and toxic elements (mercury, chromium, cesium, rubidium, lanthanum, bromine, selenium, zinc, and cobalt) in the patients with the mixt-infection of Opisthorchis and Metorchis (78 individuals) and with the Opisthorchis mono-infection (58 individuals) were significantly higher than those in healthy uninfested individuals. Among these elements, mercury and chromium showed the highest concentrations in infested patients. We suggest that the significant increase in

  20. Effects of elevated CO2 concentrations and fly ash amended soils on trace element accumulation and translocation among roots, stems and seeds of Glycine max (L.) Merr.

    PubMed

    Rodriguez, J H; Klumpp, A; Fangmeier, A; Pignata, M L

    2011-03-15

    The carbon dioxide (CO(2)) levels of the global atmosphere and the emissions of heavy metals have risen in recent decades, and these increases are expected to produce an impact on crops and thereby affect yield and food safety. In this study, the effects of elevated CO(2) and fly ash amended soils on trace element accumulation and translocation in the root, stem and seed compartments in soybean [Glycine max (L.) Merr.] were evaluated. Soybean plants grown in fly ash (FA) amended soil (0, 1, 10, 15, and 25% FA) at two CO(2) regimes (400 and 600 ppm) in controlled environmental chambers were analyzed at the maturity stage for their trace element contents. The concentrations of Br, Co, Cu, Fe, Mn, Ni, Pb and Zn in roots, stems and seeds in soybeans were investigated and their potential risk to the health of consumers was estimated. The results showed that high levels of CO(2) and lower concentrations of FA in soils were associated with an increase in biomass. For all the elements analyzed except Pb, their accumulation in soybean plants was higher at elevated CO(2) than at ambient concentrations. In most treatments, the highest concentrations of Br, Co, Cu, Fe, Mn, and Pb were found in the roots, with a strong combined effect of elevated CO(2) and 1% of FA amended soils on Pb accumulation (above maximum permitted levels) and translocation to seeds being observed. In relation to non-carcinogenic risks, target hazard quotients (TQHs) were significant in a Chinese individual for Mn, Fe and Pb. Also, the increased health risk due to the added effects of the trace elements studied was significant for Chinese consumers. According to these results, soybean plants grown for human consumption under future conditions of elevated CO(2) and FA amended soils may represent a toxicological hazard. Therefore, more research should be carried out with respect to food consumption (plants and animals) under these conditions and their consequences for human health.

  1. Modelling and mapping trace element accumulation in Sphagnum peatlands at the European scale using a geomatic model of pollutant emissions dispersion.

    PubMed

    Diaz-de-Quijano, Maria; Joly, Daniel; Gilbert, Daniel; Toussaint, Marie-Laure; Franchi, Marielle; Fallot, Jean-Michel; Bernard, Nadine

    2016-07-01

    Trace elements (TEs) transported by atmospheric fluxes can negatively impact isolated ecosystems. Modelling based on moss-borne TE accumulation makes tracking TE deposition in remote areas without monitoring stations possible. Using a single moss species from ombrotrophic hummock peatlands reinforces estimate quality. This study used a validated geomatic model of particulate matter dispersion to identify the origin of Cd, Zn, Pb and Cu accumulated in Sphagnum capillifolium and the distance transported from their emission sources. The residential and industrial sectors of particulate matter emissions showed the highest correlations with the TEs accumulated in S. capillifolium (0.28(Zn)-0.56(Cu)) and (0.27(Zn)-0.47(Cu), respectively). Distances of dispersion varied depending on the sector of emissions and the considered TE. The greatest transportation distances for mean emissions values were found in the industrial (10.6 km when correlating with all TEs) and roads sectors (13 km when correlating with Pb). The residential sector showed the shortest distances (3.6 km when correlating with Cu, Cd, and Zn). The model presented here is a new tool for evaluating the efficacy of air pollution abatement policies in non-monitored areas and provides high-resolution (200 × 200 m) maps of TE accumulation that make it possible to survey the potential impacts of TEs on isolated ecosystems. PMID:27061470

  2. Modelling and mapping trace element accumulation in Sphagnum peatlands at the European scale using a geomatic model of pollutant emissions dispersion.

    PubMed

    Diaz-de-Quijano, Maria; Joly, Daniel; Gilbert, Daniel; Toussaint, Marie-Laure; Franchi, Marielle; Fallot, Jean-Michel; Bernard, Nadine

    2016-07-01

    Trace elements (TEs) transported by atmospheric fluxes can negatively impact isolated ecosystems. Modelling based on moss-borne TE accumulation makes tracking TE deposition in remote areas without monitoring stations possible. Using a single moss species from ombrotrophic hummock peatlands reinforces estimate quality. This study used a validated geomatic model of particulate matter dispersion to identify the origin of Cd, Zn, Pb and Cu accumulated in Sphagnum capillifolium and the distance transported from their emission sources. The residential and industrial sectors of particulate matter emissions showed the highest correlations with the TEs accumulated in S. capillifolium (0.28(Zn)-0.56(Cu)) and (0.27(Zn)-0.47(Cu), respectively). Distances of dispersion varied depending on the sector of emissions and the considered TE. The greatest transportation distances for mean emissions values were found in the industrial (10.6 km when correlating with all TEs) and roads sectors (13 km when correlating with Pb). The residential sector showed the shortest distances (3.6 km when correlating with Cu, Cd, and Zn). The model presented here is a new tool for evaluating the efficacy of air pollution abatement policies in non-monitored areas and provides high-resolution (200 × 200 m) maps of TE accumulation that make it possible to survey the potential impacts of TEs on isolated ecosystems.

  3. Increased Variation in Adh Enzyme Activity in Drosophila Mutation-Accumulation Experiment Is Not Due to Transposable Elements at the Adh Structural Gene

    PubMed Central

    Aquadro, C. F.; Tachida, H.; Langley, C. H.; Harada, K.; Mukai, T.

    1990-01-01

    We present here a molecular analysis of the region surrounding the structural gene encoding alcohol dehydrogenase (Adh) in 47 lines of Drosophila melanogaster that have each accumulated mutations for 300 generations. While these lines show a significant increase in variation of alcohol dehydrogenase enzyme activity compared to control lines, we found no restriction map variation in a 13-kb region including the complete Adh structural gene and roughly 5 kb of both 5' and 3' sequences. Thus, the rapid accumulation of ADH activity variation after 28,200 allele generations does not appear to have been due to the mobilization of transposable elements into or out of the Adh structural gene region. PMID:1963870

  4. ACCUMULATION AND TISSUE DISPOSITION OF PARTICLE ASSOCIATED ELEMENTS IN THE RAT AFTER REPEATED INTRATRACHAEL ADMINISTRATION OF SOURCE PARTICLES

    EPA Science Inventory

    The goal of this study was to determine the fate of source particle tracer elements following repeated intratracheal instillation (IT) to rats. PM samples comprised Mt. St. Helens ash (MSH) with no water-soluble metals, and oil flyash emission PM (EPM) with water-leachable solubl...

  5. Accumulation of trace elements in the fruiting bodies of macrofungi in the Krusné Hory Mountains Czechoslovakia.

    PubMed

    Lepsová, A; Mejstrík, V

    1988-10-15

    The concentrations of some trace elements (Pb, Cd, Cu, Fe, Mn, Zn, Co, Ni) were determined in fruiting bodies of 20 fungal species from seven families (order Agaricales, Basidiomycetes) growing in the Krusné Hory Mountains, Czechoslovakia, where the air pollution is characterized as moderate. Samples were collected from three stands: a spruce forest, the waterlogged margin of a peat bog, and the peat bog itself. The biomass of fruiting bodies of all macrofungi was determined simultaneously. The trace element concentrations varied among trophic groups of fungi: saprophytic species (S) and those parasitic on Sphagnum (Sph) exhibited the highest concentrations, while wood-decomposing (Wd) species displayed the lowest. Several species mycorrhizal with spruce (Ms), such as Amanita umbrinolutea, Russula ochroleuca, and Xerocomus badius, also attained higher concentrations than were found for other mycorrhizal fungi. The trace element concentrations were higher in the caps than in the stems of the fungi. The fraction of trace metals retained by the biomass of fruiting bodies of fungi with respect to annual fallout is estimated at 1 0/00. Factors affecting fungal uptake of trace elements are discussed. PMID:3238419

  6. Vertical distribution of trace-element concentrations and occurrence of metallurgical slag particles in accumulated bed sediments of Lake Roosevelt, Washington, September 2002

    USGS Publications Warehouse

    Cox, S.E.; Bell, P.R.; Lowther, J.S.; Van Metre, P.C.

    2005-01-01

    Sediment cores were collected from six locations in Lake Roosevelt to determine the vertical distributions of trace-element concentrations in the accumulated sediments of Lake Roosevelt. Elevated concentrations of arsenic, cadmium, copper, lead, mercury, and zinc occurred throughout much of the accumulated sediments. Concentrations varied greatly within the sediment core profiles, often covering a range of 5 to 10 fold. Trace-element concentrations typically were largest below the surficial sediments in the lower one-half of each profile, with generally decreasing concentrations from the 1964 horizon to the surface of the core. The trace-element profiles reflect changes in historical discharges of trace elements to the Columbia River by an upstream smelter. All samples analyzed exceeded clean-up guidelines adopted by the Confederated Tribes of the Colville Reservation for cadmium, lead, and zinc and more than 70 percent of the samples exceeded cleanup guidelines for mercury, arsenic, and copper. Although 100 percent of the samples exceeded sediment guidelines for cadmium, lead, and zinc, surficial concentrations of arsenic, copper, and mercury in some cores were less than the sediment-quality guidelines. With the exception of copper, the trace-element profiles of the five cores collected along the pre-reservoir Columbia River channel typically showed trends of decreasing concentrations in sediments deposited after the 1964 time horizon. The decreasing concentrations of trace elements in the upper half of cores from along the pre-reservoir Columbia River showed a pattern of decreasing concentrations similar to reductions in trace-element loading in liquid effluent from an upstream smelter. Except for arsenic, trace-element concentrations typically were smaller at downstream reservoir locations along the pre-reservoir Columbia River. Trace-element concentration in sediments from the Spokane Arm of the reservoir showed distinct differences compared to the similarities

  7. Brome mosaic virus capsid protein regulates accumulation of viral replication proteins by binding to the replicase assembly RNA element.

    PubMed

    Yi, Guanghui; Letteney, Ester; Kim, Chul-Hyun; Kao, C Cheng

    2009-04-01

    Viruses provide valuable insights into the regulation of molecular processes. Brome mosaic virus (BMV) is one of the simplest entities with four viral proteins and three genomic RNAs. Here we report that the BMV capsid protein (CP), which functions in RNA encapsidation and virus trafficking, also represses viral RNA replication in a concentration-dependent manner by inhibiting the accumulation of the RNA replication proteins. Expression of the replication protein 2a in trans can partially rescue BMV RNA accumulation. A mutation in the CP can decrease the repression of translation. Translation repression by the CP requires a hairpin RNA motif named the B Box that contains seven loop nucleotides (nt) within the 5' untranslated regions (UTR) of BMV RNA1 and RNA2. Purified CP can bind directly to the B Box RNA with a K (d) of 450 nM. The secondary structure of the B Box RNA was determined to contain a highly flexible 7-nt loop using NMR spectroscopy, native gel analysis, and thermal denaturation studies. The B Box is also recognized by the BMV 1a protein to assemble the BMV replicase, suggesting that the BMV CP can act to regulate several viral infection processes.

  8. Accumulation of potentially toxic elements in road deposited sediments in residential and light industrial neighborhoods of Singapore.

    PubMed

    Yuen, J Q; Olin, P H; Lim, H S; Benner, S G; Sutherland, R A; Ziegler, A D

    2012-06-30

    Road deposited sediments (RDS) are a valuable environmental medium for characterizing contaminant levels in urban areas; and their associated potentially toxic elements (PTEs) can directly impact both human and aquatic health. In this study, RDS were collected from 15 co-located industrial and residential roads throughout Singapore to determine the effect of land use on contaminant levels. A second pilot study was designed to quantify the efficiency of road sweeping in removing different RDS grain size fractions from industrial and residential roads. The fine fraction (<63 μm) of all RDSs was analyzed for over 40 elements. Eleven elements that reflect geogenic and anthropogenic sources were examined in detail (Al, Co, Cr, Cu, Fe, Ni, Pb, Sb, Sc, Si, and Zn). Industrial RDS had statistically higher concentrations of Co, Cr, Fe, and Ni than residential RDS. Potentially toxic elements Cu, Pb, Sb, and Zn were enriched >10-fold at all locations compared to upper continental crust values. Concentrations of Cu, Pb and Zn exceeded aquatic sediment probable effect concentration levels, suggesting they could generate a toxic response in bottom-dwelling aquatic organisms. Traffic was equally heavy at both industrial and residential sites, but large trucks and machinery comprised a larger proportion of the traffic in the industrial areas. Traffic was not significantly correlated with the PTE (i.e., Cu, Pb, Sb and Zn) concentrations. Plausible anthropogenic contaminant sources include vehicles (e.g., brake and tire wear, vehicle emissions) and several industrial activities including metal works, oil processing, and waste incineration. Street sweeping was effective in removal of large organic debris and inorganic RDS, but it was ineffective in removing the geochemically important fraction, i.e., <125 μm.

  9. Partitioning of trace elements and metals between quasi-ultrafine, accumulation and coarse aerosols in indoor and outdoor air in schools

    NASA Astrophysics Data System (ADS)

    Viana, M.; Rivas, I.; Querol, X.; Alastuey, A.; Álvarez-Pedrerol, M.; Bouso, L.; Sioutas, C.; Sunyer, J.

    2015-04-01

    Particle size distribution patterns of trace elements and metals across three size fractions (<0.25 μm, quasi-ultrafine particles, q-UF; 0.25-2.5 μm, accumulation particles; 2.5-10 μm, coarse particles) were analysed in indoor and outdoor air at 39 primary schools across Barcelona (Spain). Special attention was paid to emission sources in each particle size range. Results evidenced the presence in q-UF particles of high proportions of elements typically found in coarse PM (Ca, Al, Fe, Mn or Na), as well as several potentially health-hazardous metals (Mn, Cu, Sn, V, Pb). Modal shifts (e.g., from accumulation to coarse or q-UF particles) were detected when particles infiltrated indoors, mainly for secondary inorganic aerosols. Our results indicate that the location of schools in heavily trafficked areas increases the abundance of q-UF particles, which infiltrate indoors quite effectively, and thus may impact children exposure to these health-hazardous particles.

  10. Accumulation of trace elements, pesticides, and polychlorinated biphenyls in sediments and the clam Corbicula manilensis of the Apalachicola River, Florida

    USGS Publications Warehouse

    Elder, J.F.; Mattraw, H.C., Jr.

    1984-01-01

    A survey of trace element and synthetic organic compound concentrations in botton materials was conducted on the Apalachichola River in northwest Florida in 1979-80 as part of the Apalachicola River Quality Assessment. Substances analyzed included trace elements (predominantly heavy metals), organochlorine insecticides, organophosphorus insecticides, chlorinated phenoxy-acid herbicides, and polychlorinated biphenyls (PCBs). Three kinds of materials were surveyed: fine-grained sediments, whole-body tissue of the Asiatic clam Corbicula manilensis, and bottom-load organic detritus. No hazardous levels of any of the substances were found. Concentrations in the fine-grained sediments and clams were generally at least ten times lower than maximum limits considered safe for biota of aquatic systems. A comparison of trace-substance data from the Apalachicola River with data from Lake Seminole (upstream) and Apalachicola Bay (downstream) showed lower concentrations in riverine clams. Sediment concentrations in all parts of the system were comparable. Most trace substances in the Apalachicola River enter the river from the upstream part of the basin (the Chattahoochee and Flint Rivers in Georgia and Alabama) and from nonpoint sources throughout the basin. There are no major point discharges along the Apalachicola. Trend analysis was limited by the scope of the study, but did not reveal any spatial or temporal trends in concentrations of any of the substances analyzed. Concentrations of organic compounds and most metals in Corbicula manilensis did not correlate with those in sediments.

  11. Trace element and nutrient accumulation in sunflower plants two years after the Aznalcóllar mine spill.

    PubMed

    Madejón, P; Murillo, J M; Marañón, T; Cabrera, F; Soriano, M A

    2003-05-20

    The failure of a tailing pond dam at the Aznalcóllar pyrite mine (SW Spain) in April 1998 released a toxic spill affecting approximately 4300 ha along the Agrio and Guadiamar valleys. Two years later, we have studied yield and concentration of mineral nutrients and trace elements in sunflower plants grown in the spill-affected soil, and in an adjacent unaffected soil as comparison. The study has been carried out in plants at seedling (V4) and mature (R8) stages. Shoot and root biomass of sunflower seedlings was significantly smaller in the affected soil than in the unaffected soil, but there was no significant difference at the mature stage. Oil production was greater in the spill-affected plants. We have not detected any 'fertilising' effect caused by the acid waters of the spill on the main nutrient (N, P and Ca) acquisition, as documented in 1998 for sunflower plants flooded by the spill. Sunflower plants growing in the spill-affected soil reached adequate levels of nutrients. None of the trace elements measured-As, Cd, Cu, Pb and Tl-reached levels either phytotoxic or toxic for humans or animals in seeds and the above-ground part of the spill-affected plants. We evaluate the potential use of sunflower plants for phytoremediation. The potential for phytoextraction is very low; however, it may be used for soil conservation. The production of oil (usable for industrial purposes) may add some value to this crop.

  12. Tlr4-mutant mice are resistant to acute alcohol-induced sterol-regulatory element binding protein activation and hepatic lipid accumulation.

    PubMed

    Zhang, Zhi-Hui; Liu, Xiao-Qian; Zhang, Cheng; He, Wei; Wang, Hua; Chen, Yuan-Hua; Liu, Xiao-Jing; Chen, Xi; Xu, De-Xiang

    2016-01-01

    Previous studies demonstrated that acute alcohol intoxication caused hepatic lipid accumulation. The present study showed that acute alcohol intoxication caused hepatic lipid accumulation in Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic sterol-regulatory element binding protein (SREBP)-1, a transcription factor regulating fatty acid and triglyceride (TG) synthesis, was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic Fas, Acc, Scd-1 and Dgat-2, the key genes for fatty acid and TG synthesis, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Additional experiment showed that hepatic MyD88 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic NF-κB was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Moreover, hepatic GSH content was reduced and hepatic MDA level was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic CYP2E1 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic p67phox and gp91phox, two NADPH oxidase subunits, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Alpha-phenyl-N-t-butylnitrone (PBN), a free radical spin-trapping agent, protected against alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. In conclusion, Tlr4-mutant mice are resistant to acute alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. PMID:27627966

  13. Tlr4-mutant mice are resistant to acute alcohol-induced sterol-regulatory element binding protein activation and hepatic lipid accumulation

    PubMed Central

    Zhang, Zhi-Hui; Liu, Xiao-Qian; Zhang, Cheng; He, Wei; Wang, Hua; Chen, Yuan-Hua; Liu, Xiao-Jing; Chen, Xi; Xu, De-Xiang

    2016-01-01

    Previous studies demonstrated that acute alcohol intoxication caused hepatic lipid accumulation. The present study showed that acute alcohol intoxication caused hepatic lipid accumulation in Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic sterol-regulatory element binding protein (SREBP)-1, a transcription factor regulating fatty acid and triglyceride (TG) synthesis, was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic Fas, Acc, Scd-1 and Dgat-2, the key genes for fatty acid and TG synthesis, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Additional experiment showed that hepatic MyD88 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic NF-κB was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Moreover, hepatic GSH content was reduced and hepatic MDA level was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic CYP2E1 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic p67phox and gp91phox, two NADPH oxidase subunits, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Alpha-phenyl-N-t-butylnitrone (PBN), a free radical spin-trapping agent, protected against alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. In conclusion, Tlr4-mutant mice are resistant to acute alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. PMID:27627966

  14. Distribution of mercury in Gypsy Cortinarius caperatus mushrooms from several populations: an efficient accumulator species and estimated intake of element.

    PubMed

    Falandysz, Jerzy

    2014-12-01

    Mushroom Cortinarius caperatus is one of the several edible wild-grown species that are widely collected by fanciers. For specimens collected from 20 spatially and distantly distributed sites in Poland the median values of Hg contents of caps ranged from 0.81 to 2.4mgkg(-1) dry matter and in stipes they were 2.5-fold lower. C. caperatus efficiently accumulates Hg and the median values of the bioconcentration factor for caps range from 120 to 18 and for stipes from 47 to 7.3. This mushroom even when collected at background (uncontaminated) forested areas could be a source of elevated intake of Hg. The irregular consumption of the caps or whole fruiting bodies is not considered to pose a risk. Frequent eating of C. caperatus during the fruiting season by fanciers should be avoided because of possible health risk from Hg. Available data on Hg contents of C. caperatus from several places in Europe are also summarized.

  15. Vertical accumulation of potential toxic elements in a semiarid system that is influenced by an abandoned gold mine

    NASA Astrophysics Data System (ADS)

    Sánchez-Martínez, Martha A.; Marmolejo-Rodríguez, Ana J.; Magallanes-Ordóñez, Víctor R.; Sánchez-González, Alberto

    2013-09-01

    The mining zone at El Triunfo, Baja California Sur, Mexico, was exploited for gold extraction for 200 years. This area includes more than 100 abandoned mining sites. These sites contain mine tailings that are highly contaminated with potential toxic elements (PTE), such as As, Cd, Pb, Sb, Zn, and other associated elements. Over time, these wastes have contaminated the sediments in the adjacent fluvial systems. Our aim was to assess the vertical PTE variations in the abandoned mining zone and in the discharge of the main arroyo into a small lagoon at the Pacific Ocean. Sediments were collected from the two following locations in the mining zone near the arroyo basin tailings: 1) an old alluvial terrace (Overbank) and a test pit (TP) and 2) two sediment cores locations at the arroyo discharge into a hypersaline small lagoon. Samples were analyzed by ICP-MS, ICP-OES, and INAA and the methods were validated. The overbank was the most contaminated and had As, Cd, Pb, Sb, and Zn concentrations of 8690, 226, 84,700, 17,400, and 42,600 mg kg-1, respectively, which decreased with depth. In addition, the TP contained elevated As, Cd, Pb, Sb, and Zn concentrations of 694, 18.8, 5001, 39.2, and 4170 mg kg-1, respectively. The sediment cores were less contaminated. However, the As, Cd, Pb, Sb, and Zn concentrations were greater than the concentrations that are generally found in the Earth's crust. The normalized enrichment factors (NEFs), which were calculated from the background concentrations of these elements in the system, showed that extremely severe As, Cd, Pb, Sb, and Zn (NEF > 50) enrichment occurred at the overbank. The TP was severe to very severely enriched with As, Cd, Pb, Sb, and Zn (NEF = 10-50). The sediment cores had a severe enrichment of As, Pb, and Zn (NEF = 10-25). Their vertical profiles showed that anthropogenic influences occurred in the historic sediment deposition at the overbank and TP and in the sediment cores. In addition, the As, Pb, and Zn

  16. Single-Kernel Ionomic Profiles Are Highly Heritable Indicators of Genetic and Environmental Influences on Elemental Accumulation in Maize Grain (Zea mays)

    PubMed Central

    Baxter, Ivan R.; Ziegler, Gregory; Lahner, Brett; Mickelbart, Michael V.; Foley, Rachel; Danku, John; Armstrong, Paul; Salt, David E.; Hoekenga, Owen A.

    2014-01-01

    The ionome, or elemental profile, of a maize kernel can be viewed in at least two distinct ways. First, the collection of elements within the kernel are food and feed for people and animals. Second, the ionome of the kernel represents a developmental end point that can summarize the life history of a plant, combining genetic programs and environmental interactions. We assert that single-kernel-based phenotyping of the ionome is an effective method of analysis, as it represents a reasonable compromise between precision, efficiency, and power. Here, we evaluate potential pitfalls of this sampling strategy using several field-grown maize sample sets. We demonstrate that there is enough genetically determined diversity in accumulation of many of the elements assayed to overcome potential artifacts. Further, we demonstrate that environmental signals are detectable through their influence on the kernel ionome. We conclude that using single kernels as the sampling unit is a valid approach for understanding genetic and environmental effects on the maize kernel ionome. PMID:24489944

  17. Single-kernel ionomic profiles are highly heritable indicators of genetic and environmental influences on elemental accumulation in maize grain (Zea mays).

    PubMed

    Baxter, Ivan R; Ziegler, Gregory; Lahner, Brett; Mickelbart, Michael V; Foley, Rachel; Danku, John; Armstrong, Paul; Salt, David E; Hoekenga, Owen A

    2014-01-01

    The ionome, or elemental profile, of a maize kernel can be viewed in at least two distinct ways. First, the collection of elements within the kernel are food and feed for people and animals. Second, the ionome of the kernel represents a developmental end point that can summarize the life history of a plant, combining genetic programs and environmental interactions. We assert that single-kernel-based phenotyping of the ionome is an effective method of analysis, as it represents a reasonable compromise between precision, efficiency, and power. Here, we evaluate potential pitfalls of this sampling strategy using several field-grown maize sample sets. We demonstrate that there is enough genetically determined diversity in accumulation of many of the elements assayed to overcome potential artifacts. Further, we demonstrate that environmental signals are detectable through their influence on the kernel ionome. We conclude that using single kernels as the sampling unit is a valid approach for understanding genetic and environmental effects on the maize kernel ionome.

  18. The sequestration of trace elements by willow (Salix purpurea)--which soil properties favor uptake and accumulation?

    PubMed

    Cloutier-Hurteau, Benoît; Turmel, Marie-Claude; Mercier, Catherine; Courchesne, François

    2014-03-01

    The effect of soil properties on trace element (TE) extraction by the Fish Creek willow cultivar was assessed in a 4-month greenhouse experiment with two contrasted soils and two mycorrhizal treatments (Rhizophagus irregularis and natives). Aboveground tissues represented more than 82 % of the willow biomass and were the major sink for TE. Cadmium and Zn were concentrated in leaves, while As, Cu, Ni, and Pb were mostly found in roots. Willow bioconcentration ratios were below 0.20 for As, Cu, Ni, and Pb and reached 10.0 for Cd and 1.97 for Zn. More significant differences in willow biomass, TE concentrations, and contents were recorded between soil types than between mycorrhizal treatments. A slight significant increase in Cu extraction by willow in symbiosis with Rhizophagus irregularis was observed and was linked to increased shoot biomass. Significant regression models between TE in willow and soil properties were found in leaves (As, Ni), shoots (As, Cd, Cu, Ni), and roots (As, Cu, Pb). Most of the explanation was shared between soil water-soluble TE and fertility variables, indicating that TE phytoextraction is related to soil properties. Managing interactions between TE and major nutrients in soil appeared as a key to improve TE phytoextraction by willows.

  19. Macro and trace elements in Common Chanterelle (Cantharellus cibarius) mushroom from the European background areas in Poland: Composition, accumulation, dietary exposure and data review for species.

    PubMed

    Falandysz, Jerzy; Drewnowska, Małgorzata

    2015-01-01

    This paper gives an up-to-date information on accumulation, occurrence, intake and possible health risks associated with noxious metallic elements (Ag, Cd, Hg, Pb) among mineral constituents (Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn) contained in Common Chanterelle (Cantharellus cibarius) mushrooms, a species subjected to a broad use within the domestic market of Poland and widely exported abroad, and presents a short review of data from the available literature. The tasty values of C. cibarius seem to be more rated than the essential minerals contained in its flesh and nominally taken with 1,000 g of fresh fruiting bodies eaten per capita annually, while the contents of toxic or potentially toxic metals, such as Cd, Pb, Hg and Ag, are much below the tolerance limits.

  20. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  1. Migration of trace elements from basalt substrate to co-located vegetation (lichens and mosses) at the Wudalianchi volcanos, Northeast China

    NASA Astrophysics Data System (ADS)

    Bao, Yuan; Ju, Yiwen; Li, Boping; Sun, Yimin

    2016-03-01

    Vegetation (e.g., lichens and mosses) living on the basalt substrate have potential to accumulate trace elements in their tissues. Here, we analyze the trace elements in basalt (collected from major volcanic center to jet plate places, representing four different eruption phases) and adjacent lichens and mosses to assess their elemental source-receptor relation. The results indicate that As, Sr, Mo, Cd, and Ba are enriched in basalt, and depleted in lichens and mosses. However, Zn, Hg, and Pb are enriched in lichens and mosses and depleted in basalt. Moreover, with the increase of basalt age, Cr, Mn, Fe, Ni, and Cu are gradually enriched in lichen and moss, but gradually depleted in basalt. Compared with transition metals, large ion lithophiles, the platinum group, and rare earth elements, Cr, Co, Cu, Zn, and Os are more easily absorbed by No. 1 lichen. Specifically, S is highly assimilated in vegetation, with a highest value of 166, followed by I, C, Pb, Zn, and Hg. In addition, the hydrogen and oxygen isotopic compositions of water samples suggest that the surface water in the Wenbo area came from meteoric waters in summer with a high humidity, while the underground water in the Beiyaoquan area came from meteoric waters in winter with a low humidity.

  2. Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

    NASA Astrophysics Data System (ADS)

    He, B.; Dai, M.; Huang, W.; Liu, Q.; Chen, H.; Xu, L.

    2010-10-01

    Organic matter in surface sediments from the upper reach of the Pearl River Estuary and Lingdingyang Bay, as well as the adjacent northern South China Sea shelf was characterized using a variety of techniques, including elemental (C and N) ratio, bulk stable organic carbon isotopic composition (δ13C), and carbohydrate composition analyses. Total organic carbon (TOC) content was 1.21±0.45% in the upper reach, down to 1.00±0.22% in Lingdingyang Bay and to 0.80±0.10% on the inner shelf and 0.58±0.06% on the outer shelf. δ13C values ranged from -25.1‰ to -21.3‰ in Lingdingyang Bay and the South China Sea shelf, with a trend of enrichment seawards. The spatial trend in C/N ratios mirrored that of δ13C, with a substantial decrease in C/N ratio offshore. Total carbohydrate yields ranged from 22.1 to 26.7 mg (100 mg OC)-1, and typically followed TOC concentrations in the estuarine and shelf sediments. Total neutral sugars, as detected by the nine major monosaccharides (lyxose, rhamnose, ribose, arabinose, fucose, xylose, galactose, mannose, and glucose), were between 4.0 and 18.6 mg (100 mg OC)-1 in the same sediments, suggesting that significant amounts of carbohydrates were not neutral aldoses. Using a two end-member mixing model based on δ13C values and C/N ratios, we estimated that the terrestrial organic carbon contribution to the surface sediment TOC was ca. 78±11% for Lingdingyang Bay, 34±4% for the inner shelf, and 5.5±1% for the outer shelf. The molecular composition of the carbohydrate in the surface sediments also suggested that the inner estuary was rich in terrestrially derived carbohydrates but that their contribution decreased offshore. A relatively high abundance of deoxyhexoses in the estuary and shelf indicated a considerable bacterial source of these carbohydrates, implying that sediment organic matter had undergone extensive degradation and/or transformation during transport. Sediment budget based on calculated regional accumulation rates

  3. Accumulation of As, Cd and selected trace elements in tubers of Scirpus aritimus L. from Doñana marshes (South Spain)

    USGS Publications Warehouse

    Madejon, P.; Murillo, J.M.; Maranon, T.; Espinar, J.L.; Cabrera, F.

    2006-01-01

    The collapse of a pyrite-mining, tailing dam on 1998 contaminated an area of 4286 ha along the Agrio and Guadiamar river valleys in southern Spain. Over 2700 ha of the Doñana marshes, an important wintering area for wetland European birds, were contaminated. This study reports analyses of the tubers of Scirpus maritimus (an important food for greylag geese, Anser anser) collected in 2000 in the “Entremuros” (spill-affected area) and in nearby unaffected Doñana marshes (control areas). In the spill-affected area mean tuber tissue concentrations of Cd (0.25 mg kg−1) and Zn (61 mg kg−1) were greater than in those tubers from the control area (0.02 mg kg−1 for Cd, and 22 mg kg−1 for Zn); values of Cd and Zn in “Entremuros” (samples collected two years after the mine spill) were much smaller than those reported only a few months after the accident. Trace elements (As, Fe, Mn and Tl, and to a lesser extent Cd and Pb) showed a preferential accumulation in the outer skin of tubers. Surprisingly, concentrations of As and Fe were greater in tubers from some marsh sites not affected by the mine-spill than in tubers from the “Entremuros”. We suggest that relic river channels within the Doñana marshes may be contaminated by trace elements from historic mining activities. An exhaustive study of macrophytes and other plant species in this area is recommended to identify potential risks to wildlife.

  4. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  5. Lead, platinum and other heavy elements in the primary cosmic radiation: HEAO-3 results

    NASA Technical Reports Server (NTRS)

    Waddington, C. J.; Binns, W. R.; Brewster, N. R.; Fixsen, D. J.; Garrard, T. L.; Israel, M. H.; Klarmann, J.; Newport, B. J.; Stone, E. C.

    1986-01-01

    An observation of the abundances of cosmic-ray lead and platinum-group nuclei using data from the HEAO-3 Heavy Nuclei Experiment (HNE) which consisted of ion chambers mounted on both sides of a plastic Cherenkov counter (Binns et al., 1981) is reported. Further analysis with more stringent selections, inclusion of additional data, and a calibration at the LBL Bevalac, have allowed the determination of the abundance ratio of lead and the platinum group of elements for particles that had a cutoff rigidity R(c) 5 GV. The observed ratio for Pb/Pt is distinctly lower than that predicted by any of the standard models for cosmic ray sources. It is possible that the difference is not an indication that the cosmic ray source composition is greatly different from that of the solar system, but rather that there is less Pb in the solar system and in the r-process than is assumed in the standard models.

  6. Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

    NASA Astrophysics Data System (ADS)

    He, B.; Dai, M.; Huang, W.; Liu, Q.; Chen, H.; Xu, L.

    2010-04-01

    Organic matter in surface sediments from the upper reach of the Pearl River Estuary and Lingdingyang Bay, as well as the adjacent northern South China Sea shelf was characterized by a variety of techniques, including elemental (C and N), stable carbon isotopic (δ 13C) composition, as well as molecular-level analyses. Total organic carbon (TOC) content was 1.61±1.20% in the upper reach down to 1.00±0.22% in Lingdingyang Bay and to 0.80±0.10% on the inner shelf and 0.58±0.06% on the outer shelf. δ13C values ranged from -25.11‰ to -21.28‰ across the studied area, with a trend of enrichment seaward. The spatial trend in C/N ratios mirrored that of δ13C, with a substantial decrease in C/N ratio from 10.9±1.3 in the Lingdingyang Bay surface sediments to 6.5±0.09 in the outer shelf surface sediments. Total carbohydrate yields ranged from 22.1 to 26.7 mg (100 mg OC)-1, and typically followed TOC concentrations in the estuarine and shelf sediments, suggesting that the relative abundance of total carbohydrate was fairly constant in TOC. Total neutral sugars as detected by the nine major monosaccharides (lyxose, rhamnose, ribose, arabinose, fucose, xylose, galactose, mannose, and glucose) yielded between 4.0 and 18.6 mg (100 mg OC)-1 in the same sediments, suggesting that a significant amount of carbohydrates were not neutral aldoses. The bulk organic matter properties, isotopic composition and C/N ratios, combined with molecular-level carbohydrate compositions were used to assess the sources and accumulation of terrestrial organic matter in the Pearl River Estuary and the adjacent northern South China Sea shelf. Results showed a mixture of terrestrial riverine organic carbon with in situ phytoplankton organic carbon in the areas studied. Using a two end-member mixing model based on δ13C values and C/N ratios, we estimated that the terrestrial organic carbon contribution to the surface sediment TOC was ca. 57±13% for Lingdingyang Bay, 19±2% for the inner shelf

  7. Minor elements in magnetic concentrates from the Syenite-Shonkinite Province, southern Asir, Kingdom of Saudi Arabia

    USGS Publications Warehouse

    Overstreet, W.C.; Day, G.W.; Botinelly, Theodore; VanTrump, George

    1987-01-01

    Magnetic concentrates from 106 localities in three plutons of syenite and one pluton of shonkinite in the southern Asir were analyzed spectrographically for 31 elements to determine if anomaly-enhancement techniques would identify mineralization not disclosed by conventional geochemical sample media. Positive anomalies are lacking for all elements except vanadium. Vanadium contents as high as 0.7 percent were identified in magnetic concentrates from the syenite pluton to the southeast of Suq al Ithnayn, but magnetite is sparse. This observation indicates a need to reexamine magnetite-rich drill core for possible ore-grade tenors in vanadium from the zoned pluton at Lakathah. Experimental analyses for platinum-group metals in magnetic concentrates from layered mafic plutons at Jabal Sha'i', Jabal al Ashshar, and Hishshat al Hawi should be performed to determine whether micron-size particles of the platinum-group metals are present in mafic rocks of the Arabian Shield.

  8. A multivariate analysis of the accumulation and fractionation of major and trace elements in agricultural soils in Hidalgo State, Mexico irrigated with raw wastewater.

    PubMed

    Lucho-Constantino, Carlos A; Alvarez-Suárez, Miriam; Beltrán-Hernández, Rosa I; Prieto-García, Francisco; Poggi-Varaldo, Héctor M

    2005-04-01

    We evaluated the accumulation and distribution of major and trace elements in agricultural soils of District 03 (DR03) in the State of Hidalgo, Mexico, irrigated with raw wastewaters for an average of 20 years. Samples of topsoils (0-30 cm depth) were extracted using a modified Tessier method. Total concentrations of the species tested were in the ranges of 675-1176 mg K kg(-1), 277.9-1001 mg Na kg(-1), 6,708-81,854 mg Ca kg(-1), 23,800-106,974 mg Mg kg(-1), 9.2-123.8 mg B kg(-1), 0.6-1.9 mg Cd kg(-1), 11.6-27.4 mg Cr kg(-1), 3.9-47.0 mg Pb kg(-1). Concentrations of As and Hg were very low. Concentrations of total Cd, Cr and Pb were generally below the maximum permissible levels set by the regulations of the European Union except for cadmium, which was in the middle of the maximum European range allowed for two soils. Regarding lead, one soil (S5) could reach the maximum permissible level of the EU in 6 more years of continued irrigation. On the other hand, contents of Pb in the most mobile fractions ("e" in this work) were significant (range: 3-28%). This distribution translated into concentrations of soluble plus exchangeable lead of approximately 2 mg Pb kg(-1) in three of six soils, significantly higher than the Swiss tolerance limit of 1.0 mg Pb kg(-1) for mobile fractions of lead in soils. Multivariate analysis of the data (Pearson correlation and principal component analysis) quantitatively confirmed that: (i) there is a strong covariance between boron contents and several variables representing the salinity of soils (electrolytic conductivity, a variety of alkaline and alkaline-earth total and fraction concentrations). It appears that there is a problem with high boron content in soils, although the salinity is high only for one of the soils (S3); (ii) a significant correlation among irrigation time, lead content (total, fraction easily exchangeable and bound to organic matter and sulfides) and organic carbon in soils was found; (iii) another association

  9. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  10. Accumulation of antimony and other potentially toxic elements in plants around a former antimony mine located in the Ribes Valley (Eastern Pyrenees)

    NASA Astrophysics Data System (ADS)

    Bech, Jaume; Corrales, Isabel; Duran, Paola; Roca, Núria; Tume, Pedro; Barceló, Juan; Poschenrieder, Charlotte

    2010-05-01

    Soil contamination by antimony is of increasing environmental concern due to the use of this amphoterous p-block element in many industrial applications such as flame retardant, electronics, alloys, rubber and textile industries. However, little is still known about the response of plants to antimony. Here we report on the accumulation of antimony and other potentially toxic elements (mainly As, Pb and Cu) in plants growing around a former antimony mine in the ribes Valley located in the Eastern Pyrenees (424078E, 4686100N alt. 1145 m.a.s.l) that was operating approximately between the years 1870 to 1960. The ore mineral veins are included in quartz gangue. The main ores were: Sulphides: Stibnite (Sb2S3), Pyrite (FeS2), Sphalerite (ZnS), Arsenopyrite (FeAs), Galenite (PbS), Chalcopyrite (CuFeS2), Tetrahydrite (Cu5Sb2S3). Sulphosals: Boulangerite (5PbS•2Sb2S3), Jamesonite (4PbS•FeS•3Sb2S3), Zinckenite (6PbS•7Sb2S3), Plagionite (5PbS•4Sb2S3), Bournonite PbCu (Sb,As)S3, Pyrargirite (Ag3SbS3). Soil and plant samples were taken at five locations with different levels of Sb, As, and polymetallic contamination. Both pseudototal (aqua regia soluble) and extractable (EDTA) concentrations of metals from sites with low (sites 1 and 2), moderate (site 3 and 4) and high (sites 5 and 6) pollutant burdens were studied. The range of agua regia and EDTA values in mgkg-1 is as follows: Sb 8-2904 and 0.88-44; As: 33-16186 and 3.2-167; Pb: 79-4794 and 49-397; Cu: 66-712 and 48-56 mg•kg-1, respectively). While sites 1 to 4 had alkaline soil pH (7.4-8.7), sites 5 and 6 were acidic with values of 6 and 4.6, respectively. Different herbaceous plant species (Poa annua, Echium vulgare, Sonchus asper, Barbera verna among others) at the low and moderately polluted sites were able to efficiently restrict Sb and As transport to shoots showing average concentration ranges between 5.5 and 23 mg/kg As and 1.21 mg/kg and 4.9 mg/kg Sb. However, at the highly polluted acidic sites (5 and

  11. Platinum Element Group and Other Metal Element Variations at the Permo-Triassic Boundary in Kashmir and British Columbia and Their Significance

    NASA Astrophysics Data System (ADS)

    Brookfield, M. E.; Schnellnutt, G.; Qi, L.; Hannigan, R.; Bhat, G. M.; Wignall, P.

    2009-05-01

    The end Permian marks the greatest extinction in the geological record, but there is little consensus on whether it was caused by terrestrial or extraterrestrial factors. We report here detailed analyses of platinum group element(PGE) and other metals from relatively narrowly spaced (30 cm. in Kashmir) intervals in two expanded sections from the Permo-Triassic northern and southern hemispheres that confirm a terrestrial volcanic source for the elements. But a mechanism is required that can distribute such elements world-wide from their volcanic sources, currently only exposed in the Permo-Triassic northern hemisphere.

  12. Study of new mononuclear platinum group metal complexes containing η 5 and η 6 - Carbocyclic ligands and nitrogen based derivatives and formation of helices due to N sbnd H⋯Cl interactions

    NASA Astrophysics Data System (ADS)

    Gupta, Gajendra; Gloria, Sairem; Das, Babulal; Rao, Kollipara Mohan

    2010-08-01

    A quite general approach for the preparation of η 5- and η 6-cyclichydrocarbon platinum group metal complexes is reported. The dinuclear arene ruthenium complexes [(η 6-arene)Ru(μ-Cl)Cl] 2 (arene = C 6H 6, C 10H 14 and C 6Me 6) and η 5-pentamethylcyclopentadienyl rhodium and iridium complexes [(η 5-C 5Me 5)M(μ-Cl)Cl] 2 (M = Rh and Ir) reacts with two equivalents of the ligands 2-chloro-3-(pyrazolyl)quinoxaline ( L 1) and di-(2-pyridyl)amine ( L 2) in presence of NH 4PF 6 to afford the corresponding mononuclear complexes of the type [(η 6-arene)Ru(L 1)Cl]PF 6 {arene = C 6H 6 ( 1), C 10H 14 ( 2) and C 6Me 6 ( 3)}, [(η 6-arene)Ru(L 2)Cl]PF 6 {arene = C 6H 6 ( 4), C 10H 14 ( 5) and C 6Me 6 ( 6)}, and [(η 5-C 5Me 5)M(L 1)Cl]PF 6 {M = Rh ( 7), Ir ( 8)} and [(η 5-C 5Me 5)M(L 2)Cl]PF 6 {M = Rh ( 9), Ir ( 10)}. However the mononuclear η 5-cyclopentadienyl analogues such as [(η 5-C 5H 5)Ru(PPh 3) 2Cl], [(η 5-C 5H 5)Os(PPh 3) 2Br], [(η 5-C 5Me 5)Ru(PPh 3) 2Cl] and [(η 5-C 9H 7)Ru(PPh 3) 2Cl] complexes react in presence of one equivalent of ligands 2-chloro-3-(pyrazolyl)quinoxaline ( L 1) and di-(2-pyridyl)amine ( L 2) and one equivalent of NH 4PF 6 in methanol yielded mononuclear complexes [(η 5-C 5H 5)Ru(PPh 3)(L 1)]PF 6 ( 11), [(η 5-C 5H 5)Os(PPh 3)(L 1)]PF 6 ( 12), [(η 5-C 5Me 5)Ru(PPh 3)(L 1)]PF 6 ( 13) and [(η 5-C 9H 7)Ru(PPh 3)(L 1)]PF 6 ( 14) and [(η 5-C 5H 5)Ru(PPh 3)(L 2)]PF 6 ( 15), [(η 5-C 5H 5)Os(PPh 3)(L 2)]PF 6 ( 16), [(η 5-C 5Me 5)Ru(PPh 3)(L 2)]PF 6 ( 17) and [(η 5-C 9H 7)Ru(PPh 3)(L 2)]PF 6 ( 18) respectively. These compounds have been systematically characterized by IR, NMR and mass spectrometry. The molecular structures of 2, 4 and 15 have been established by single crystal X-ray diffraction study and some of the representative complexes have also been studied by UV-visible spectroscopy. The crystal packing diagram of complex 4 reveals that the cation [(η 6-C 6H 6)Ru(L 2)Cl] + is engaged in non-covalent interaction. This compound

  13. Single kernel ionomic profiles are highly heritable indicators of genetic and environmental influences on elemental accumulation in maize grain (Zea mays)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ionome, or elemental profile, of a maize kernel represents at least two distinct ideas. First, the collection of elements within the kernel are food, feed and feedstocks for people, animals and industrial processes. Second, the ionome of the kernel represents a developmental end point that can s...

  14. Accumulation of Trace Metal Elements (Cu, Zn, Cd, and Pb) in Surface Sediment via Decomposed Seagrass Leaves: A Mesocosm Experiment Using Zostera marina L.

    PubMed Central

    Konuma, Susumu; Nakamura, Yoshiyuki

    2016-01-01

    Accumulation of Cu, Zn, Cd, and Pb in the sediment of seagrass ecosystems was examined using mesocosm experiments containing Zostera marina (eelgrass) and reference pools. Lead was approximately 20-fold higher in the surface sediment in the eelgrass pool than in eelgrass leaves and epiphytes on the eelgrass leaves, whereas zinc and cadmium were significantly lower in the surface sediment than in the leaves, with intermediate concentrations in epiphytes. Copper concentrations were similar in both the surface sediment and leaves but significantly lower in epiphytes. Carbon and nitrogen contents increased significantly with increasing δ13C in surface sediments of both the eelgrass and reference pools. Copper, Zn, Cd, and Pb also increased significantly with increasing δ13C in the surface sediment in the eelgrass pool but not in the reference pool. By decomposition of eelgrass leaves with epiphytes, which was examined in the eelgrass pool, copper and lead concentrations increased more than 2-fold and approximately a 10-fold, whereas zinc and cadmium concentrations decreased. The high copper and lead concentrations in the surface sediment result from accumulation in decomposed, shed leaves, whereas zinc and cadmium remobilized from decomposed shed leaves but may remain at higher concentrations in the leaves than in the original sediments. The results of our mesocosm study demonstrate that whether the accumulation or remobilization of trace metals during the decomposition of seagrass leaves is trace metal dependent, and that the decomposed seagrass leaves can cause copper and lead accumulation in sediments in seagrass ecosystems. PMID:27336306

  15. Accumulation of Trace Metal Elements (Cu, Zn, Cd, and Pb) in Surface Sediment via Decomposed Seagrass Leaves: A Mesocosm Experiment Using Zostera marina L.

    PubMed

    Hosokawa, Shinya; Konuma, Susumu; Nakamura, Yoshiyuki

    2016-01-01

    Accumulation of Cu, Zn, Cd, and Pb in the sediment of seagrass ecosystems was examined using mesocosm experiments containing Zostera marina (eelgrass) and reference pools. Lead was approximately 20-fold higher in the surface sediment in the eelgrass pool than in eelgrass leaves and epiphytes on the eelgrass leaves, whereas zinc and cadmium were significantly lower in the surface sediment than in the leaves, with intermediate concentrations in epiphytes. Copper concentrations were similar in both the surface sediment and leaves but significantly lower in epiphytes. Carbon and nitrogen contents increased significantly with increasing δ13C in surface sediments of both the eelgrass and reference pools. Copper, Zn, Cd, and Pb also increased significantly with increasing δ13C in the surface sediment in the eelgrass pool but not in the reference pool. By decomposition of eelgrass leaves with epiphytes, which was examined in the eelgrass pool, copper and lead concentrations increased more than 2-fold and approximately a 10-fold, whereas zinc and cadmium concentrations decreased. The high copper and lead concentrations in the surface sediment result from accumulation in decomposed, shed leaves, whereas zinc and cadmium remobilized from decomposed shed leaves but may remain at higher concentrations in the leaves than in the original sediments. The results of our mesocosm study demonstrate that whether the accumulation or remobilization of trace metals during the decomposition of seagrass leaves is trace metal dependent, and that the decomposed seagrass leaves can cause copper and lead accumulation in sediments in seagrass ecosystems.

  16. Mining Critical Metals and Elements from Seawater: Opportunities and Challenges.

    PubMed

    Diallo, Mamadou S; Kotte, Madhusudhana Rao; Cho, Manki

    2015-08-18

    The availability and sustainable supply of technology metals and valuable elements is critical to the global economy. There is a growing realization that the development and deployment of the clean energy technologies and sustainable products and manufacturing industries of the 21st century will require large amounts of critical metals and valuable elements including rare-earth elements (REEs), platinum group metals (PGMs), lithium, copper, cobalt, silver, and gold. Advances in industrial ecology, water purification, and resource recovery have established that seawater is an important and largely untapped source of technology metals and valuable elements. This feature article discusses the opportunities and challenges of mining critical metals and elements from seawater. We highlight recent advances and provide an outlook of the future of metal mining and resource recovery from seawater.

  17. Mining Critical Metals and Elements from Seawater: Opportunities and Challenges.

    PubMed

    Diallo, Mamadou S; Kotte, Madhusudhana Rao; Cho, Manki

    2015-08-18

    The availability and sustainable supply of technology metals and valuable elements is critical to the global economy. There is a growing realization that the development and deployment of the clean energy technologies and sustainable products and manufacturing industries of the 21st century will require large amounts of critical metals and valuable elements including rare-earth elements (REEs), platinum group metals (PGMs), lithium, copper, cobalt, silver, and gold. Advances in industrial ecology, water purification, and resource recovery have established that seawater is an important and largely untapped source of technology metals and valuable elements. This feature article discusses the opportunities and challenges of mining critical metals and elements from seawater. We highlight recent advances and provide an outlook of the future of metal mining and resource recovery from seawater. PMID:25894365

  18. Nested insertions and accumulation of indels are negatively correlated with abundance of mutator-like transposable elements in maize and rice.

    PubMed

    Zhao, Dongyan; Jiang, Ning

    2014-01-01

    Mutator-like transposable elements (MULEs) are widespread in plants and were first discovered in maize where there are a total of 12,900 MULEs. In comparison, rice, with a much smaller genome, harbors over 30,000 MULEs. Since maize and rice are close relatives, the differential amplification of MULEs raised an inquiry into the underlying mechanism. We hypothesize this is partly attributed to the differential copy number of autonomous MULEs with the potential to generate the transposase that is required for transposition. To this end, we mined the two genomes and detected 530 and 476 MULEs containing transposase sequences (candidate coding-MULEs) in maize and rice, respectively. Over 1/3 of the candidate coding-MULEs harbor nested insertions and the ratios are similar in the two genomes. Among the maize elements with nested insertions, 24% have insertions in coding regions and over half of them harbor two or more insertions. In contrast, only 12% of the rice elements have insertions in coding regions and 19% have multiple insertions, suggesting that nested insertions in maize are more disruptive. This is because most nested insertions in maize are from LTR retrotransposons, which are large in size and are prevalent in the maize genome. Our results suggest that the amplification of retrotransposons may limit the amplification of DNA transposons but not vice versa. In addition, more indels are detected among maize elements than rice elements whereas defects caused by point mutations are comparable between the two species. Taken together, more disruptive nested insertions combined with higher frequency of indels resulted in few (6%) coding-MULEs that may encode functional transposases in maize. In contrast, 35% of the coding-MULEs in rice retain putative intact transposase. This is in addition to the higher expression frequency of rice coding-MULEs, which may explain the higher occurrence of MULEs in rice than that in maize.

  19. Accumulation features of trace elements in mass-stranded harbor seals (Phoca vitulina) in the North Sea coast in 2002: the body distribution and association with growth and nutrition status.

    PubMed

    Agusa, Tetsuro; Yasugi, Shin-ya; Iida, Asami; Ikemoto, Tokutaka; Anan, Yasumi; Kuiken, Thijs; Osterhaus, Albert D M E; Tanabe, Shinsuke; Iwata, Hisato

    2011-05-01

    Body distribution and growth- and nutritional status-dependent accumulation of 21 trace elements were investigated in harbor seals (Phoca vitulina) stranded in the North Sea coast in 2002. Higher concentrations and burdens of Mn, Se, Mo, Ag, Sn, Hg, and Bi in the liver, Cd in the kidney, As in the blubber, and Co, Sr, and Ba in the bone were observed. Significant positive correlations of hepatic Se, Mo, Ag, Cd, Sn, Hg, Tl, and Bi with standard body length were found, while significant negative relationships were detected for Mn, As, Rb, Sr, and Sb in the liver. Concentrations of Co, Se, Sr, Sn, Hg, and Bi in the liver, V, Sr, Ag, Sn, and Hg in the kidney, V, Mn, Co, Rb, Sr, Sn, Ba, and Pb in the blubber increased with decreasing blubber thickness of harbor seals, indicating enrichment of these elements in the target tissue by emaciation.

  20. Origin, patterns and anthropogenic accumulation of potentially toxic elements (PTEs) in surface sediments of the Avilés estuary (Asturias, northern Spain).

    PubMed

    Sierra, C; Boado, C; Saavedra, A; Ordóñez, C; Gallego, J R

    2014-09-15

    Sediment quality has been assessed within the Avilés estuary, an important industrial area in the NW of Spain. The study started with a geochemical characterization of the superficial sediments that revealed some anomalous metal(oid)s concentrations in sensitive areas such as beaches or dunes. These data were studied by means of multivariate statistical techniques and enrichment factors calculation to evaluate the correlations and geochemical origin within the different elements. A novel approach using the combination of enrichment factors with a sequential application of factor analysis, clustering and kriging was essential to identify the possible sources of pollution. The collected information suggested that Cd (strongly correlated with Zn and Pb) was the potentially toxic element most widely distributed and problematic. Furthermore, particulate emissions from Zn metallurgy, as well as dust generated by the mineral loading and stockpile activities in the port were identified as the most important sources of pollution.

  1. Accumulation and tissue distribution of heavy metals and essential elements in loggerhead turtles (Caretta caretta) from Spanish Mediterranean coastline of Murcia.

    PubMed

    Jerez, Silvia; Motas, Miguel; Cánovas, Régulo Angel; Talavera, Jesús; Almela, Ramón Miguel; Del Río, Alejandro Bayón

    2010-01-01

    Sea turtles are of increasing interest as potential bioindicators of the heavy metal pollution in marine ecosystems. In the present work, concentrations of heavy metals and essential elements (As, Cd, Hg, Pb, Se, Zn) in different organs and tissues (liver, kidney, muscle, bone, blood, central nervous system and skin) of loggerhead sea turtles (Caretta caretta) were determined from stranded animals found along the Spanish Mediterranean coastlines of Murcia. Relatively high average levels of As (skin: 52.13 microg g(-1) dry weight; muscle: 40.95 microg g(-1) dry weight), and especially high individual levels of Zn in muscle tissue (1002.4 microg g(-1) dry weight) were detected. Furthermore, a significant degree of organotrophism of Cd was observed in kidney tissue. The concentrations detected, the distribution among the tissues and the differences observed between juvenile and adult specimens are generally compatible with chronic exposure to the elements studied, whilst levels produced by acute exposure were ruled out.

  2. Origin, patterns and anthropogenic accumulation of potentially toxic elements (PTEs) in surface sediments of the Avilés estuary (Asturias, northern Spain).

    PubMed

    Sierra, C; Boado, C; Saavedra, A; Ordóñez, C; Gallego, J R

    2014-09-15

    Sediment quality has been assessed within the Avilés estuary, an important industrial area in the NW of Spain. The study started with a geochemical characterization of the superficial sediments that revealed some anomalous metal(oid)s concentrations in sensitive areas such as beaches or dunes. These data were studied by means of multivariate statistical techniques and enrichment factors calculation to evaluate the correlations and geochemical origin within the different elements. A novel approach using the combination of enrichment factors with a sequential application of factor analysis, clustering and kriging was essential to identify the possible sources of pollution. The collected information suggested that Cd (strongly correlated with Zn and Pb) was the potentially toxic element most widely distributed and problematic. Furthermore, particulate emissions from Zn metallurgy, as well as dust generated by the mineral loading and stockpile activities in the port were identified as the most important sources of pollution. PMID:25113098

  3. Possible lin between elevated accumulation of trace elements and canine distemper virus infection in the Caspian seals (Phoca caspica) stranded in 2000 and 2001

    NASA Astrophysics Data System (ADS)

    Shinsuke, T.; Takashi, K.; Yasumi, A.; Tokutaka, I.; Reiji, K.

    2003-05-01

    In the Caspian Sea, a die-off of thousands of Caspian seals (Phoca caspica) occurred in 1997 and 2000. While a direct cause for these deaths seems to be canine distemper virus (CDV) infection, immunosuppression due to environmental pollutants is considered as one of the possible explanations for the development of the disease. The purpose of this work is to examine whether exposure to trace metals could be one of the factors involved in the mass mortality of Caspian seals. Concentrations of 13 trace elements weredetermined in liver, kidney and muscle of Caspian seals found stranded along the coasts of the Caspian Sea in 2000 and 2001. Concentrations of toxic elemen ts (Ag, Cd, Hg, Tl and Pb) in the Caspian seals collected in 2000 and 2001 were comparable to or lower than those in healthy Caspian seals collected in 1993 and 1998 and in seals from other regions, suggesting that these elements would not be the causative agent for the death of Caspian seals. In contrast, Zn and Fe concentrations in the stranded Caspian seals were apparently higher than those in seals from other locations. These results suggest the disturbance in homeostatic control and nutritional statu s of essential elements in the stranded Caspian seals.

  4. Improved stratigraphic dating at a low accumulation Alpine ice core through laser ablation trace element profiling at sub-mm depth resolution

    NASA Astrophysics Data System (ADS)

    Bohleber, Pascal; Spaulding, Nicole; Mayewski, Paul; Sneed, Sharon; Handley, Mike; Erhardt, Tobias; Wagenbach, Dietmar

    2015-04-01

    The small scale Colle Gnifetti glacier saddle (4450 m asl, Monte Rosa region) is the only ice core drilling site in the European Alps with a net accumulation low enough to offer multi-millennia climate records. However, a robust interpretation of such long term records (i.e. mineral dust, stable water isotopes) at the Colle Gnifetti (CG) multi core array is strongly challenged by depositional noise associated with a highly irregular annual layer stratigraphy. In combination with a relatively large vertical strain rate and rapid layer thinning, annual layer counting gets increasingly ambiguous as of approximately 100 years. In addition, this prevents clear attribution of likely volcanic horizons to historical eruption dates. To improve stratigraphic dating under such intricate conditions, we deployed laser ablation (LA) ICP-MS at sub-mm sample resolution. We present here the first LA impurity profiles from a new Colle Gnifetti ice core drilled 73 m to bedrock in 2013 at a site where the net snow accumulation is around 20 cm w.e. per year. We contrast the LA signal variability (including Ca, Fe, Na) to continuous flow analyses (CFA) records at cm-resolution (Ca, Na, melt water conductivity, micro- particle) recorded over the whole core length. Of special concern are the lower 28 m to bedrock, which have been continuously profiled in LA Ca, thus offering the direct comparison of Ca-signals between CFA and LA. By this means, we first validate at upper depths LA based annual layer identification through agreement with CFA based counting efforts before demonstrating the LA based counting still works at depths where CFA derived annual layers become spurious since embedded in strong, multi-year cycles. Finally, LA ice core profiling of our CG core has potential for not only dating improvement but also reveals benefits in resolving highly thinned basal ice sections including accounting for micro-structural features such as grain boundaries.

  5. Influence of soil properties on trace element availability and plant accumulation in a Mediterranean salt marsh polluted by mining wastes: implications for phytomanagement.

    PubMed

    Conesa, H M; María-Cervantes, A; Alvarez-Rogel, J; González-Alcaraz, M N

    2011-09-15

    The aims of this study were to determine the factors which control metal and As phytoavailability in the different microenvironments (Sand Dunes, Salt Flat, Dry River and Shrubs) present at a Mediterranean salt marsh polluted by mining wastes. We performed a field study following a plot sampling survey. The analyses of soil parameters (pH, electrical conductivity (EC), organic carbon contents, etc.), total metal and As concentrations and their phytoavailability assessed with EDTA were related to each microenvironment and the corresponding plant species uptake. The averages of pH and EC were slightly alkaline (pH ≈ 7.5) and saline (≈ 2.2 to 17.1 dS m(-1)) respectively. The soil samples from the Salt Flat subzone showed the highest metal concentrations (e.g. 51 mg kg(-1) Cd, 11,600 mg kg(-1) Pb) while for As, the highest concentrations occurred in the Dry River (380 mg kg(-1) As). The total metal and EDTA-extractable concentrations occurred as it follows: Salt Flat>Dry River>Degraded Dunes>Shrubs. In relation to plant metal and As accumulation, the highest root concentrations were obtained in the species from the Salt Flat subzone: ~17 mg kg(-1) As, ~620 mg kg(-1) Pb, for both, Juncus maritimus and Arthrocnemum macrostachyum. However the highest metal and As shoot concentrations occurred in species from the Sand Dunes: ~23 mg kg(-1) As ~270 mg kg(-1) Pb for Dittrichia viscosa; ~23 mg kg(-1) As, ~390 mg kg(-1) Zn for Crucianella maritima. The occurrence of edaphic gradients including salinity and texture determined the vegetation distribution. However, it cannot be concluded that there was a disturbance due to metal(loid)s soil concentrations in terms of vegetation composition except in the Degraded Dunes and Dry River. The higher EDTA-extractable concentrations were coincidental with the most saline soils but this did not result in higher metal(loid)s plant accumulation.

  6. Accumulation of 20 elements in great cormorant (Phalacrocorax carbo) and its main prey, common carp (Cyprinus carpio) and Prussian carp (Carassius gibelio).

    PubMed

    Skoric, Stefan; Visnjić-Jeftic, Zeljka; Jaric, Ivan; Djikanovic, Vesna; Mickovic, Branislav; Nikcevic, Miroslav; Lenhardt, Mirjana

    2012-06-01

    In this study, 20 heavy metals and trace elements (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Si, Se, Sr and Zn) were analyzed in different tissues (muscle, liver, intestine, feather and bone) of the great cormorant (Phalacrocorax carbo) and in different tissues (muscle, liver, gills, kidney and gonad) of their main prey (common carp-Cyprinus carpio and Prussian carp-Carassius gibelio) during the nesting season. Cormorant and fish specimens were collected at the Ečka Fishing Farm (Serbia) and from the nearby river. Principal components analysis (PCA) showed that cormorant livers were differentiated from other four tissues by higher concentrations of Hg, Fe, Cu and Mo, feathers by higher concentrations of Al and Si, and bones by higher concentrations of Sr and Mg. Differentiation among the three age classes of cormorants was observed only with regard to elemental concentrations in their feathers: subadult cormorants were differentiated by higher Hg and Zn concentrations, while the adults were separated by higher concentrations of Fe. In comparison with their prey (common carp and Prussian carp) cormorants were differentiated by higher concentrations of Fe, Hg and Cu in the muscle. Toxic mercury concentrations above 4μgg(-1)dw were determined in the liver of juvenile cormorants, as well as in the liver and feathers of subadults. Hg concentrations were significantly correlated among all studied tissues. Cormorant had significantly higher concentrations of Fe and Hg in muscle and liver than two studied fish species. PMID:22494478

  7. Killing of VRE Enterococcus faecalis by commensal strains: Evidence for evolution and accumulation of mobile elements in the absence of competition.

    PubMed

    Gaca, Anthony O; Gilmore, Michael S

    2016-01-01

    Enterococci are members of the gastrointestinal tract of humans and most animals that, over the past 3 decades, have emerged as leading causes of multidrug resistant hospital acquired infection (HAI). In addition to their general hardiness, many traits have entered enterococcal lineages through horizontal gene transfer, which has led to the evolution of pathogenic hospital-associated lineages uniquely adapted for survival and proliferation in the antibiotic perturbed ecology of the gastrointestinal tract. We recently observed that the accretion of mobile genetic elements in the prototype vancomycin resistant E. faecalis, clinical isolate V583, renders it unable to co-exist with native enterococci in healthy human fecal flora. In this addendum, we discuss how these findings inform our understanding of how multidrug resistant enterococci evolve, and the implications for the development of treatments that limit colonization and spread of highly antibiotic refractory microbes of this type. PMID:26939857

  8. Spatial Variation in the Accumulation of Elements in Thalli of the Lichen Pseudevernia furfuracea (L.) Zopf Transplanted Around a Biomass Power Plant in Italy.

    PubMed

    Lucadamo, Lucio; Corapi, Anna; Loppi, Stefano; De Rosa, Rosanna; Barca, Donatella; Vespasiano, Giovanni; Gallo, Luana

    2016-04-01

    Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months at 32 sites located in and around an industrial area of S Italy whose main anthropogenic sources of atmospheric trace elements are a biomass power plant and vehicular emissions. Meteorological stations were deployed at four sites for finer detection of local wind patterns. The station near the biomass power plant showed a significant S-SE wind component not detectable by measurements made at the regional scale or by the other local meteorological stations. Sb, Sn, and Mo showed a very high degree of covariance and a statistically significant correlation with traffic rate. No element concentrations in the exposed thalli were correlated with distance from the biomass power plant, although Ti and Co concentrations showed a significant correlation with the "Potential Number of Times the Winds coming from the biomass power plant Reach each exposure Site" (PNTWRS). This value is calculated dividing the time (minutes) during the experimental trimester that the wind blows from the power plant into each of the four geographical sides by the time (minutes) the winds passing through the power plant take to reach the exposure sites in each of the four geographical sides.) during the period of thalli transplantation. Moreover, there were significant differences among clusters of sites with different levels of enrichment of Ti, Co, Al, V, and Cu and a "local control" group. These results, together with the high covariance of the Al-Ti and V-Co pairs, indicate an association between the biomass power plant and spatial variation of Ti, Co, Al, and V levels in the transplanted lichens. The nature of the fuels used in the biomass power plant explains the spatial variation of As, Cr, Cu, and Zn concentrations. PMID:26546421

  9. Spatial Variation in the Accumulation of Elements in Thalli of the Lichen Pseudevernia furfuracea (L.) Zopf Transplanted Around a Biomass Power Plant in Italy.

    PubMed

    Lucadamo, Lucio; Corapi, Anna; Loppi, Stefano; De Rosa, Rosanna; Barca, Donatella; Vespasiano, Giovanni; Gallo, Luana

    2016-04-01

    Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months at 32 sites located in and around an industrial area of S Italy whose main anthropogenic sources of atmospheric trace elements are a biomass power plant and vehicular emissions. Meteorological stations were deployed at four sites for finer detection of local wind patterns. The station near the biomass power plant showed a significant S-SE wind component not detectable by measurements made at the regional scale or by the other local meteorological stations. Sb, Sn, and Mo showed a very high degree of covariance and a statistically significant correlation with traffic rate. No element concentrations in the exposed thalli were correlated with distance from the biomass power plant, although Ti and Co concentrations showed a significant correlation with the "Potential Number of Times the Winds coming from the biomass power plant Reach each exposure Site" (PNTWRS). This value is calculated dividing the time (minutes) during the experimental trimester that the wind blows from the power plant into each of the four geographical sides by the time (minutes) the winds passing through the power plant take to reach the exposure sites in each of the four geographical sides.) during the period of thalli transplantation. Moreover, there were significant differences among clusters of sites with different levels of enrichment of Ti, Co, Al, V, and Cu and a "local control" group. These results, together with the high covariance of the Al-Ti and V-Co pairs, indicate an association between the biomass power plant and spatial variation of Ti, Co, Al, and V levels in the transplanted lichens. The nature of the fuels used in the biomass power plant explains the spatial variation of As, Cr, Cu, and Zn concentrations.

  10. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

  11. Particle size distributions of metal and non-metal elements in an urban near-highway environment

    NASA Astrophysics Data System (ADS)

    Hays, Michael D.; Cho, Seung-Hyun; Baldauf, Richard; Schauer, James J.; Shafer, Martin

    2011-02-01

    Determination of the size-resolved elemental composition of near-highway particulate matter (PM) is important due to the health and environmental risks it poses. In the current study, twelve 24 h PM samples were collected (in July-August 2006) using a low-pressure impactor positioned 20 m from a Raleigh, North Carolina interstate. The interstate supported ˜125,000 vehicles/d, the majority of which were light-duty gasoline passenger vehicles. The overall near-highway PM mass size distribution was trimodal with a major accumulation mode peak at 500-800 nm. PM mass levels reflected daily traffic activity, while mean near-highway PM 10 (33 ± 7.5 μg m -3), PM 2.5 (29 ± 6.8 μg m -3), and PM 0.1 (1.4 ± 0.3 μg m -3) mass levels varied less than 24% over the two week sampling period. The elemental composition of the impactor-collected PM was investigated using magnetic sector inductively coupled plasma-mass spectroscopy (SF-ICPMS). Accumulation mode sulfur (7 ± 4% w/w) was the major inorganic constituent detected at the near-highway site followed by coarse mode group IA and IIA elements likely from re-suspension of crustal matter. As expected, elements regularly detected in asphalt, vehicle, catalyst (e.g., Pt, Rh, and Pd), brake, and tire wear (e.g., Cu and Sb) were also found in the near highway PM. Maximum concentrations of the platinum group, rare earth, and common brake and tire wear elements were observed at d50 = 1-2 μm, d50 = 1-4 μm, and d50 ≥ 1-4 μm, respectively. Ten of the eleven metals listed as EPA air toxics (Mn, Cr, Sb, Ni, Pb, As, Co, Cd, Se, and Be) were detected in each PM size fraction but were generally enriched in PM 0.1. Several biologically antagonistic suites of metals (Cd, Cu, and V) were found in multiple PM size modes. Some of these metals showed erratic size distributions with daily changes in enrichment (e.g., Ni, Zn, Cd, As, and Cu) and particle size, suggesting a variety of emissions and metal exposure scenarios occurring in the

  12. Growth and elemental accumulation of plants grown in acidic soil amended with coal fly ash-sewage sludge co-compost.

    PubMed

    Wong, Jonathan W C; Selvam, Ammaiyappan

    2009-10-01

    A greenhouse experiment was conducted to evaluate the growth and heavy-metal accumulation of Brassica chinensis and Agropyron elongatum in 10 and 25% ash-sludge co-compost (ASC)--amended loamy acidic soil (pH 4.51) at two different application rates: 20% and 40% (v/v). Soil pH increased, whereas electrical conductivity decreased with the amendment of ASC to soil. Bioavailable Cu, Zn, and Mn contents of ASC-amended soil decreased, whereas Ni, Pb, and B contents increased. Concentrations of bioavailable Cu, Zn, and Mn in sludge compost (SC)-amended soils were 5.57, 20.8, and 8.19 mg kg(-1), respectively. These concentrations were significantly lower than those in soil receiving an application rate of 20 or 25% ASC as 2.64, 8.48, and 5.26 mg kg(-1), respectively. Heavy metals and B contents of the composting mass significantly increased with an increase in ASC application rate from 20 to 40% (6.2 to 16.6 mg kg(-1) for 10% ASC- and 9.4 to 18.6 mg kg(-1) for 25% ASC-amended soil. However, when the ash content in co-compost increased from 10 to 25% during composting, bioavailable heavy-metal contents decreased. However, B contents increased with an increase in ash content. Addition of co-composts increased the dry-weight yield of the plants, and this increase was more obvious as the ash amendment rate in the co-composts and the ASC application rate increased. In case of B. chinensis, the biomass of 2.84 g/plant for 40% application of 25% ASC was significantly higher than SC (0.352 g/plant), which was 40% application of 10% ASC (0.434 g/plant) treatments. However, in A. elongatum, the differences between biomass of plants grown with 10% (1.34-1.94 g/ plant) and 25% ASC (2.12-2.21 g/plant) were not significantly different. Furthermore, there were fewer plant-available heavy metals in 25% ASC, which decreased the uptake of heavy metals by plants. ASC was favorable in increasing the growth of B. chinensis and A. elongatum. The optimal ash amendment to the sludge composting

  13. Growth and elemental accumulation of plants grown in acidic soil amended with coal fly ash-sewage sludge co-compost

    SciTech Connect

    Wong, J.W.C.; Selvam, A.

    2009-10-15

    A greenhouse experiment was conducted to evaluate the growth and heavy-metal accumulation of Brassica chinensis and Agropyron elongatum in 10 and 25% ash-sludge co-compost (ASC)-amended loamy acidic soil (pH 4.51) at two different application rates: 20% and 40% (v/v). Soil pH increased, whereas electrical conductivity decreased with the amendment of ASC to soil. Bioavailable Cu, Zn, and Mn contents of ASC-amended soil decreased, whereas Ni, Pb, and B contents increased. Concentrations of bioavailable Cu, Zn, and Mn in sludge compost (SC)-amended soils were 5.57, 20.8, and 8.19 mg kg{sup -1}, respectively. These concentrations were significantly lower than those in soil receiving an application rate of 20 or 25% ASC as 2.64, 8.48, and 5.26 mg kg(-1), respectively. Heavy metals and B contents of the composting mass significantly increased with an increase in ASC application rate from 20 to 40% (6.2 to 16.6 mg kg{sup -1} for 10% ASC- and 9.4 to 18.6 mg kg{sup -1} for 25% ASC-amended soil. However, when the ash content in co-compost increased from 10 to 25% during composting, bioavailable heavy-metal contents decreased. However, B contents increased with an increase in ash content. Addition of co-composts increased the dry-weight yield of the plants, and this increase was more obvious as the ash amendment rate in the co-composts and the ASC application rate increased. In case of B. chinensis, the biomass of 2.84 g/plant for 40% application of 25% ASC was significantly higher than SC (0.352 g/plant), which was 40% application of 10% ASC (0.434 g/plant) treatments. However, in A. elongatum, the differences between biomass of plants grown with 10% (1.34-1.94 g/ plant) and 25% ASC (2.12-2.21 g/plant) were not significantly different. ASC was favorable in increasing the growth of B. chinensis and A. elongatum. The optimal ash amendment to the sludge composting and ASC application rates were at 25 and 20%, respectively.

  14. Multi-axis dose accumulation of noninvasive image-guided breast brachytherapy through biomechanical modeling of tissue deformation using the finite element method

    PubMed Central

    Ghadyani, Hamid R.; Bastien, Adam D.; Lutz, Nicholas N.; Hepel, Jaroslaw T.

    2015-01-01

    Purpose Noninvasive image-guided breast brachytherapy delivers conformal HDR 192Ir brachytherapy treatments with the breast compressed, and treated in the cranial-caudal and medial-lateral directions. This technique subjects breast tissue to extreme deformations not observed for other disease sites. Given that, commercially-available software for deformable image registration cannot accurately co-register image sets obtained in these two states, a finite element analysis based on a biomechanical model was developed to deform dose distributions for each compression circumstance for dose summation. Material and methods The model assumed the breast was under planar stress with values of 30 kPa for Young's modulus and 0.3 for Poisson's ratio. Dose distributions from round and skin-dose optimized applicators in cranial-caudal and medial-lateral compressions were deformed using 0.1 cm planar resolution. Dose distributions, skin doses, and dose-volume histograms were generated. Results were examined as a function of breast thickness, applicator size, target size, and offset distance from the center. Results Over the range of examined thicknesses, target size increased several millimeters as compression thickness decreased. This trend increased with increasing offset distances. Applicator size minimally affected target coverage, until applicator size was less than the compressed target size. In all cases, with an applicator larger or equal to the compressed target size, > 90% of the target covered by > 90% of the prescription dose. In all cases, dose coverage became less uniform as offset distance increased and average dose increased. This effect was more pronounced for smaller target–applicator combinations. Conclusions The model exhibited skin dose trends that matched MC-generated benchmarking results within 2% and clinical observations over a similar range of breast thicknesses and target sizes. The model provided quantitative insight on dosimetric treatment variables

  15. Miniature Inverted–Repeat Transposable Elements (MITEs) Have Been Accumulated through Amplification Bursts and Play Important Roles in Gene Expression and Species Diversity in Oryza sativa

    PubMed Central

    Lu, Chen; Chen, Jiongjiong; Zhang, Yu; Hu, Qun; Su, Wenqing; Kuang, Hanhui

    2012-01-01

    Miniature inverted–repeat transposable elements (MITEs) are predicted to play important roles on genome evolution. We developed a BLASTN-based approach for de novo identification of MITEs and systematically analyzed MITEs in rice genome. The genome of rice cultivar Nipponbare (Oryza sativa ssp. japonica) harbors 178,533 MITE-related sequences classified into 338 families. Pairwise nucleotide diversity and phylogenetic tree analysis indicated that individual MITE families were resulted from one or multiple rounds of amplification bursts. The timing of amplification burst varied considerably between different MITE families or subfamilies. MITEs are associated with 23,623 (58.2%) genes in rice genome. At least 7,887 MITEs are transcribed and more than 3,463 were transcribed with rice genes. The MITE sequences transcribed with rice coding genes form 1,130 pairs of potential natural sense/antisense transcripts. MITEs generate 23.5% (183,837 of 781,885) of all small RNAs identified from rice. Some MITE families generated small RNAs mainly from the terminals, while other families generated small RNAs predominantly from the central region. More than half (51.8%) of the MITE-derived small RNAs were generated exclusively by MITEs located away from genes. Genome-wide analysis showed that genes associated with MITEs have significantly lower expression than genes away from MITEs. Approximately 14.8% of loci with full-length MITEs have presence/absence polymorphism between rice cultivars 93-11 (O. sativa ssp. indica) and Nipponbare. Considering that different sets of genes may be regulated by MITE-derived small RNAs in different genotypes, MITEs provide considerable diversity for O. sativa. PMID:22096216

  16. SU-E-J-96: Multi-Axis Dose Accumulation of Noninvasive Image-Guided Breast Brachytherapy Through Biomechanical Modeling of Tissue Deformation Using the Finite Element Method

    SciTech Connect

    Rivard, MJ; Ghadyani, HR; Bastien, AD; Lutz, NN; Hepel, JT

    2015-06-15

    Purpose: Noninvasive image-guided breast brachytherapy delivers conformal HDR Ir-192 brachytherapy treatments with the breast compressed, and treated in the cranial-caudal and medial-lateral directions. This technique subjects breast tissue to extreme deformations not observed for other disease sites. Given that, commercially-available software for deformable image registration cannot accurately co-register image sets obtained in these two states, a finite element analysis based on a biomechanical model was developed to deform dose distributions for each compression circumstance for dose summation. Methods: The model assumed the breast was under planar stress with values of 30 kPa for Young’s modulus and 0.3 for Poisson’s ratio. Dose distributions from round and skin-dose optimized applicators in cranial-caudal and medial-lateral compressions were deformed using 0.1 cm planar resolution. Dose distributions, skin doses, and dose-volume histograms were generated. Results were examined as a function of breast thickness, applicator size, target size, and offset distance from the center. Results: Over the range of examined thicknesses, target size increased several millimeters as compression thickness decreased. This trend increased with increasing offset distances. Applicator size minimally affected target coverage, until applicator size was less than the compressed target size. In all cases, with an applicator larger or equal to the compressed target size, > 90% of the target covered by > 90% of the prescription dose. In all cases, dose coverage became less uniform as offset distance increased and average dose increased. This effect was more pronounced for smaller target-applicator combinations. Conclusions: The model exhibited skin dose trends that matched MC-generated benchmarking results and clinical measurements within 2% over a similar range of breast thicknesses and target sizes. The model provided quantitative insight on dosimetric treatment variables over

  17. Overexpression of SREBP1 (sterol regulatory element binding protein 1) promotes de novo fatty acid synthesis and triacylglycerol accumulation in goat mammary epithelial cells.

    PubMed

    Xu, H F; Luo, J; Zhao, W S; Yang, Y C; Tian, H B; Shi, H B; Bionaz, M

    2016-01-01

    Sterol regulatory element binding protein 1 (SREBP1; gene name SREBF1) is known to be the master regulator of lipid homeostasis in mammals, including milk fat synthesis. The major role of SREBP1 in controlling milk fat synthesis has been demonstrated in bovine mammary epithelial cells. Except for a demonstrated role in controlling the expression of FASN, a regulatory role of SREBP1 on milk fat synthesis is very likely, but has not yet been demonstrated in goat mammary epithelial cells (GMEC). To explore the regulatory function of SREBP1 on de novo fatty acids and triacylglycerol synthesis in GMEC, we overexpressed the mature form of SREBP1 (active NH2-terminal fragment) in GMEC using a recombinant adenovirus vector (Ad-nSREBP1), with Ad-GFP (recombinant adenovirus of green fluorescent protein) as control, and infected the GMEC for 48 h. In infected cells, we assessed the expression of 20 genes related to milk fat synthesis using real time-quantitative PCR, the protein abundance of SREBP1 and FASN by Western blot, the production of triacylglycerol, and the fatty acid profile. Expression of SREBF1 was modest in mammary compared with the other tissues in dairy goats but its expression increased approximately 30-fold from pregnancy to lactation. The overexpression of the mature form of SREBP1 was confirmed by >200-fold higher expression of SREBF1 in Ad-nSREBP1 compared with Ad-GFP. We observed no changes in amount of the precursor form of SREBP1 protein but a >10-fold increase of the mature form of SREBP1 protein with Ad-nSREBP1. Compared with Ad-GFP cells (control), Ad-nSREBP1 cells had a significant increase in expression of genes related to long-chain fatty acid activation (ACSL1), transport (FABP3), desaturation (SCD1), de novo synthesis of fatty acids (ACSS2, ACLY, IDH1, ACACA, FASN, and ELOVL6), and transcriptional factors (NR1H3 and PPARG). We observed a >10-fold increase in expression of INSIG1 but SCAP was downregulated by Ad-nSREBP1. Among genes related to

  18. Overexpression of SREBP1 (sterol regulatory element binding protein 1) promotes de novo fatty acid synthesis and triacylglycerol accumulation in goat mammary epithelial cells.

    PubMed

    Xu, H F; Luo, J; Zhao, W S; Yang, Y C; Tian, H B; Shi, H B; Bionaz, M

    2016-01-01

    Sterol regulatory element binding protein 1 (SREBP1; gene name SREBF1) is known to be the master regulator of lipid homeostasis in mammals, including milk fat synthesis. The major role of SREBP1 in controlling milk fat synthesis has been demonstrated in bovine mammary epithelial cells. Except for a demonstrated role in controlling the expression of FASN, a regulatory role of SREBP1 on milk fat synthesis is very likely, but has not yet been demonstrated in goat mammary epithelial cells (GMEC). To explore the regulatory function of SREBP1 on de novo fatty acids and triacylglycerol synthesis in GMEC, we overexpressed the mature form of SREBP1 (active NH2-terminal fragment) in GMEC using a recombinant adenovirus vector (Ad-nSREBP1), with Ad-GFP (recombinant adenovirus of green fluorescent protein) as control, and infected the GMEC for 48 h. In infected cells, we assessed the expression of 20 genes related to milk fat synthesis using real time-quantitative PCR, the protein abundance of SREBP1 and FASN by Western blot, the production of triacylglycerol, and the fatty acid profile. Expression of SREBF1 was modest in mammary compared with the other tissues in dairy goats but its expression increased approximately 30-fold from pregnancy to lactation. The overexpression of the mature form of SREBP1 was confirmed by >200-fold higher expression of SREBF1 in Ad-nSREBP1 compared with Ad-GFP. We observed no changes in amount of the precursor form of SREBP1 protein but a >10-fold increase of the mature form of SREBP1 protein with Ad-nSREBP1. Compared with Ad-GFP cells (control), Ad-nSREBP1 cells had a significant increase in expression of genes related to long-chain fatty acid activation (ACSL1), transport (FABP3), desaturation (SCD1), de novo synthesis of fatty acids (ACSS2, ACLY, IDH1, ACACA, FASN, and ELOVL6), and transcriptional factors (NR1H3 and PPARG). We observed a >10-fold increase in expression of INSIG1 but SCAP was downregulated by Ad-nSREBP1. Among genes related to

  19. Heat accumulator

    SciTech Connect

    Bracht, A.

    1981-09-29

    A heat accumulator comprises a thermally-insulated reservoir full of paraffin wax mixture or other flowable or meltable heat storage mass, heat-exchangers immersed in the mass, a heat-trap connected to one of the heat-exchangers, and a heat user connected to the other heat-exchanger. Pumps circulate fluids through the heat-trap and the heat-using means and the respective heat-exchangers, and a stirrer agitates and circulates the mass, and the pumps and the stirrer and electric motors driving these devices are all immersed in the mass.

  20. The Cenomanian-Turonian oceanic anoxic event in Tibet, a real anoxic condition? Clues from Phosphorus, Carbon and Traces Elements accumulations.

    NASA Astrophysics Data System (ADS)

    Bomou, B.; Adatte, T.; Föllmi, K. B.; Caron, M.; Tantawy, A. A.; Fleitmann, D.; Matera, V.; Huang, Y.

    2009-04-01

    a plateau which ends the excursion. A bloom of Heterohelix and Guembelitria, low oxygen tolerant foraminifera, is observed in the upper part of the δ13C shift (W. archaeocretacea zone) indicative of depleted oxygen conditions. Significant peaks in Ptot is observed at the onset of the δ13C shift, followed by a depletion at the end of R. cushmani zone, persisting up to the end of W. archaeocretacea zone. In Tibet, P distribution patterns during OAE2 are quite similar to the ones observed in numerous sections in western Tethys and Central Atlantic (England, Italia, Spain and USA, Mort et al., 2007) and appear therefore to be global, coinciding partly with increased detrital inputs. Trace-metals values are under background level compared with sections characterized by strong anoxic conditions and redox sensitive elements such as Va, Ni, Co, U, generally indicative of anoxic conditions, do not show any increase during the maximum of δ13C excursion and Heterohelix and Guembelitria shifts. This suggests that dysoxic rather than anoxic conditions prevailed in Tibet area during OAE 2. Increased Mg, Na, Ca contents to the detriment of Al suggest a change to more arid climate conditions from the base of archaeocretacea zone upwards. REFERENCES JENKYNS, H.C. (1980). Cretaceous anoxic events: from continents to oceans. Journal of the Geological Society, 137, 171-188. LI, X., JENKYNS, H.C., WANG, C., HU, X., CHEN, X., WEI, Y., HUANG, Y. & CUI, J. (2006). Upper Cretaceous carbon-and oxygen-isotope stratigraphy of hemipelagic carbonate facies from southern Tibet, China. Journal of the Geological Society, 163, 375-382. MORT, H., ADATTE, T., FÖLLMI, K., KELLER, G., STEINMANN, P., MATERA, V., BERNER, Z., & STÜBEN, D. (2007). Phosphorus and the roles of productivity and nutrient recycling during Oceanic Anoxic Event 2. Geology, 35, 6, 483-486. SCHLANGER, S.O. & JENKYNS, H.C. (1976). Cretaceous anoxic events: causes and consequences. Geologie en Mijnbouw, 55, 179-184. SCHOLLE, P

  1. Distribution and accumulation of elements (As, Cu, Fe, Hg, Mn, and Zn) in tissues of fish species from different trophic levels in the Danube River at the confluence with the Sava River (Serbia).

    PubMed

    Subotić, S; Višnjić Jeftić, Ž; Spasić, S; Hegediš, A; Krpo-Ćetković, J; Lenhardt, M

    2013-08-01

    Pikeperch (Sander lucioperca), European catfish (Silurus glanis), common carp (Cyprinus carpio), and gobies (Neogobius gymnotrachelus, Neogobius melanostomus) were collected from the Danube River (Belgrade section), and samples of liver, muscle, or whole-body composites (in the case of gobies) were analyzed for As, Cu, Fe, Hg, Mn, and Zn with inductively coupled plasma optical spectrometry to find out if there was a correlation between accumulation of these elements in predatory and prey species, as well as in pairs of species with overlapping diets. Concentrations of all analyzed elements were either higher (Cu, Fe, Mn, Zn) in liver than in muscle, or equal (As, Hg), except for Hg in carp, which was higher in muscle. Mercury concentration in liver and muscle of predators (catfish, pikeperch) was significantly (<10(-4)) higher than in prey fishes (carp and gobies). The results indicate that Hg concentration was biomagnified through the food chain. Concentrations of As, Fe, and Hg in carp liver and gobies whole-body composite were similar, but carp had significantly (<10(-4)) higher values of Zn and Cu in liver. The regression analysis and trendline equations indicate that the concentrations of all tested elements, except for As in liver, and Mn and Fe in muscle, were similar in predatory fish (pikeperch and catfish), on one hand, and in prey fish (carp and gobies), on the other hand. Distinctly high Zn concentration in carp is very common in this species due to its physiology. Concentrations of Hg and Zn were higher than the maximum acceptable concentration due to the high pollution level in this section of the Danube River, accordingly posing a risk for the human consumption of these fish species.

  2. Platinum Group Metal Recycling Technology Development - Final Report

    SciTech Connect

    Lawrence Shore

    2009-08-19

    BASF Catalysts LLC, formerly Engelhard Corporation, has completed a project to recover Pt from PEM fuel cell membrane electrode assemblies. The project, which began in 2003, has met the project objective of an environmentally-friendly, cost-effective method for recovery of platinum without release of hydrogen fluoride. This has been achieved using a combination of milling, dispersion and acid leaching. 99% recovery of Pt was achieved, and this high yield can be scaled up using one vessel for a single leach and rinse. Leaching was been successfully achieved using a 10% solids level, double the original target. At this solids content, the reagent and utility costs represent ~0.35% of the Pt value of a lot, using very conservative assumptions. The main cost of the process is capital depreciation, followed by labor.

  3. Experimental investigations on the chemical state of solid fission-product elements in U3Si2

    NASA Astrophysics Data System (ADS)

    Ugajin, M.; Itoh, A.

    1994-10-01

    The uranium silicide U3Si2 has a congruent melting point of 1665 C and possesses higher uranium density (11.3 g U/cc) and higher thermal conductivity than the uranium dioxide currently used in light water reactors. U3Si2 is in use as a research reactor fuel (US Nuclear Regulatory Commission, NUREG-1313, July, 1988), representing a potentiality for power reactor fuel. A first attempt is made in this study to predict the chemical state of the solid fission-product elements comprising zirconium, molybdenum, rare earth elements, alkaline earth metals and elements of the platinum group. Ternary phase equilibria in the U-Mo-Si and U-Ru-Si systems are also investigated to supplement the fission product chemistry in U3Si2.

  4. Fractionation of highly siderophile and chalcogen elements during magma transport in the mantle: Constraints from pyroxenites of the Balmuccia peridotite massif

    NASA Astrophysics Data System (ADS)

    Wang, Zaicong; Becker, Harry

    2015-06-01

    Sulfide segregation from sulfur saturated basic magmas affects the compositions of chalcophile elements such as the highly siderophile elements (HSE) and the chalcogens S, Se, Te to variable extent. Whether this process predominantly occurs in the lower crust or in the mantle and how segregation of liquid sulfide and accumulation affects concentrations and ratios of these elements at different mantle depths and in presumed primitive basic magmas remains uncertain. Abundances of the HSE, S, Se and Te and Os isotopes in websterites and spinel clinopyroxenites of the Balmuccia peridotite massif (Ivrea-Verbano Zone, Italian Alps) provide new insight on sulfide segregation and the compositional change of melt and peridotite during magma transport in the mantle. Balmuccia websterites and clinopyroxenites formed from late Paleozoic and Mesozoic melt influx into stretched continental lithospheric mantle of the Ivrea-Verbano Zone, respectively. The HSE and chalcogen element compositions of websterites and clinopyroxenites reflect the segregation and accumulation of sulfide melt from S saturated silicate melts with different abundances and ratios of chalcogens and the HSE. The pyroxenites display large variations in abundances of the platinum group elements (PGE) and Te whereas abundances of less chalcophile elements S, Se and Re are much less variable. The fractionation between the PGE and fractionation of Re/Os, S/Se and Se/Te in the mantle pyroxenites are consistent with sulfide melt-silicate melt partitioning with a sequence of apparent coefficients of DPGE > DAu ⩾ DTe > DSe ⩾ DS ≈ DRe. Concentrations in ocean ridge basalts and in gabbros of the lower oceanic crust are also consistent with such fractionation. Websterites which have formed during refertilization of depleted peridotites display ratios of the HSE and moderately suprachondritic initial 187Os/188Os similar to interstitial sulfides of refertilized peridotites. These compositions are different from

  5. Abundances of ultraheavy elements in the cosmic radiation - Results from HEAO 3

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Israel, M. H.; Garrard, T. L.; Gibner, P. S.; Kertzman, M. P.

    1989-01-01

    An analysis is presented that, for the first time, systematically normalizes the data from the HEAO 3 heavy nuclei experiment on the cosmic-ray abundances of all the elements heavier than germanium to that of iron. In the range of atomic number Z from 33 to 60, the analysis yields abundances of odd-even element pairs. The abundances are consistent with a cosmic-ray source having a composition similar to that of the solar system, but subject to source fractionation correlated with the first ionization potential (FIP) of each element. For Z greater than 60, the analysis yields abundances of element groups. For these heaviest nuclei, we find an enhancement of the abundance of the platinum group, elements with Z of 74-80, relative to that in propagated solar system source, and a corresponding increase in the abundance of the largely secondary elements in the 62-73 range. These abundances suggest that there is an enhancement of the r-process contribution to the source nuclei in the Z greater than 60 charge region. Over the entire region of charge, standard leaky box models of propagation satisfactorily model secondary production.

  6. Neurodegeneration with Brain Iron Accumulation

    MedlinePlus

    ... Diversity Find People About NINDS NINDS Neurodegeneration with Brain Iron Accumulation Information Page Synonym(s): Hallervorden-Spatz Disease, ... done? Clinical Trials Organizations What is Neurodegeneration with Brain Iron Accumulation? Neurodegeneration with brain iron accumulation (NBIA) ...

  7. Plastids and Carotenoid Accumulation.

    PubMed

    Li, Li; Yuan, Hui; Zeng, Yunliu; Xu, Qiang

    2016-01-01

    Plastids are ubiquitously present in plants and are the organelles for carotenoid biosynthesis and storage. Based on their morphology and function, plastids are classified into various types, i.e. proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. All plastids, except proplastids, can synthesize carotenoids. However, plastid types have a profound effect on carotenoid accumulation and stability. In this chapter, we discuss carotenoid biosynthesis and regulation in various plastids with a focus on carotenoids in chromoplasts. Plastid transition related to carotenoid biosynthesis and the different capacity of various plastids to sequester carotenoids and the associated effect on carotenoid stability are described in light of carotenoid accumulation in plants. PMID:27485226

  8. Plastids and Carotenoid Accumulation.

    PubMed

    Li, Li; Yuan, Hui; Zeng, Yunliu; Xu, Qiang

    2016-01-01

    Plastids are ubiquitously present in plants and are the organelles for carotenoid biosynthesis and storage. Based on their morphology and function, plastids are classified into various types, i.e. proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. All plastids, except proplastids, can synthesize carotenoids. However, plastid types have a profound effect on carotenoid accumulation and stability. In this chapter, we discuss carotenoid biosynthesis and regulation in various plastids with a focus on carotenoids in chromoplasts. Plastid transition related to carotenoid biosynthesis and the different capacity of various plastids to sequester carotenoids and the associated effect on carotenoid stability are described in light of carotenoid accumulation in plants.

  9. Chimpanzee accumulative stone throwing.

    PubMed

    Kühl, Hjalmar S; Kalan, Ammie K; Arandjelovic, Mimi; Aubert, Floris; D'Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M; Zuberbuehler, Klaus; Boesch, Christophe

    2016-01-01

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

  10. Chimpanzee accumulative stone throwing

    PubMed Central

    Kühl, Hjalmar S.; Kalan, Ammie K.; Arandjelovic, Mimi; Aubert, Floris; D’Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E.; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J.; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M.; Zuberbuehler, Klaus; Boesch, Christophe

    2016-01-01

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites. PMID:26923684

  11. Chimpanzee accumulative stone throwing.

    PubMed

    Kühl, Hjalmar S; Kalan, Ammie K; Arandjelovic, Mimi; Aubert, Floris; D'Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M; Zuberbuehler, Klaus; Boesch, Christophe

    2016-01-01

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites. PMID:26923684

  12. It's elemental

    NASA Astrophysics Data System (ADS)

    The Periodic Table of the elements will now have to be updated. An international team of researchers has added element 110 to the Earth's armory of elements. Though short-lived—of the order of microseconds, element 110 bottoms out the list as the heaviest known element on the planet. Scientists at the Heavy Ion Research Center in Darmstadt, Germany, made the 110-proton element by colliding a lead isotope with nickel atoms. The element, which is yet to be named, has an atomic mass of 269.

  13. Accumulator with preclosing preventer

    SciTech Connect

    Murthy, R.R.; Rice, B.J.

    1981-11-24

    A guided-float accumulator suitable for use with a hydraulic system for an oil well blowout preventer is provided with a wing shut-off valve. Radially inwardly directed outlet parts are aimed at the bottom of the valve wing to generate unbalanced reaction forces which oppose the bernoulli effect forces caused by rapid movement of fluid through the chamber of the shut-off valve, thus preventing premature closing of the valve.

  14. Elemental ZOO

    NASA Astrophysics Data System (ADS)

    Helser, Terry L.

    2003-04-01

    This puzzle uses the symbols of 39 elements to spell the names of 25 animals found in zoos. Underlined spaces and the names of the elements serve as clues. To solve the puzzle, students must find the symbols that correspond to the elemental names and rearrange them into the animals' names.

  15. Heat exchanger-accumulator

    DOEpatents

    Ecker, Amir L.

    1980-01-01

    What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

  16. COST action TD1407: network on technology-critical elements (NOTICE)--from environmental processes to human health threats.

    PubMed

    Cobelo-García, A; Filella, M; Croot, P; Frazzoli, C; Du Laing, G; Ospina-Alvarez, N; Rauch, S; Salaun, P; Schäfer, J; Zimmermann, S

    2015-10-01

    The current socio-economic, environmental and public health challenges that countries are facing clearly need common-defined strategies to inform and support our transition to a sustainable economy. Here, the technology-critical elements (which includes Ga, Ge, In, Te, Nb, Ta, Tl, the Platinum Group Elements and most of the rare-earth elements) are of great relevance in the development of emerging key technologies-including renewable energy, energy efficiency, electronics or the aerospace industry. In this context, the increasing use of technology-critical elements (TCEs) and associated environmental impacts (from mining to end-of-life waste products) is not restricted to a national level but covers most likely a global scale. Accordingly, the European COST Action TD1407: Network on Technology-Critical Elements (NOTICE)-from environmental processes to human health threats, has an overall objective for creating a network of scientists and practitioners interested in TCEs, from the evaluation of their environmental processes to understanding potential human health threats, with the aim of defining the current state of knowledge and gaps, proposing priority research lines/activities and acting as a platform for new collaborations and joint research projects. The Action is focused on three major scientific areas: (i) analytical chemistry, (ii) environmental biogeochemistry and (iii) human exposure and (eco)-toxicology. PMID:26286804

  17. COST action TD1407: network on technology-critical elements (NOTICE)--from environmental processes to human health threats.

    PubMed

    Cobelo-García, A; Filella, M; Croot, P; Frazzoli, C; Du Laing, G; Ospina-Alvarez, N; Rauch, S; Salaun, P; Schäfer, J; Zimmermann, S

    2015-10-01

    The current socio-economic, environmental and public health challenges that countries are facing clearly need common-defined strategies to inform and support our transition to a sustainable economy. Here, the technology-critical elements (which includes Ga, Ge, In, Te, Nb, Ta, Tl, the Platinum Group Elements and most of the rare-earth elements) are of great relevance in the development of emerging key technologies-including renewable energy, energy efficiency, electronics or the aerospace industry. In this context, the increasing use of technology-critical elements (TCEs) and associated environmental impacts (from mining to end-of-life waste products) is not restricted to a national level but covers most likely a global scale. Accordingly, the European COST Action TD1407: Network on Technology-Critical Elements (NOTICE)-from environmental processes to human health threats, has an overall objective for creating a network of scientists and practitioners interested in TCEs, from the evaluation of their environmental processes to understanding potential human health threats, with the aim of defining the current state of knowledge and gaps, proposing priority research lines/activities and acting as a platform for new collaborations and joint research projects. The Action is focused on three major scientific areas: (i) analytical chemistry, (ii) environmental biogeochemistry and (iii) human exposure and (eco)-toxicology.

  18. Solids Accumulation Scouting Studies

    SciTech Connect

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.

    2012-09-26

    The objective of Solids Accumulation activities was to perform scaled testing to understand the behavior of remaining solids in a Double Shell Tank (DST), specifically AW-105, at Hanford during multiple fill, mix, and transfer operations. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles containing plutonium could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste staging tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids: Gibbsite, Zirconia, Sand, and Stainless Steel, with stainless steel particles representing the heavier particles, e.g., plutonium, and supernatant were charged to the test tank and rotating liquid jets were used to mix most of the solids while the simulant was pumped out. Subsequently, the volume and shape of the mounds of residual solids and the spatial concentration profiles for the surrogate for heavier particles were measured. Several techniques were developed and equipment designed to accomplish the measurements needed and they included: 1. Magnetic particle separator to remove simulant stainless steel solids. A device was designed and built to capture these solids, which represent the heavier solids during a waste transfer from a staging tank. 2. Photographic equipment to determine the volume of the solids mounds. The mounds were photographed as they were exposed at different tank waste levels to develop a composite of topographical areas. 3. Laser rangefinders to determine the volume of

  19. The present state of knowledge on the high-technology elements in porphyry copper deposit from Romania

    NASA Astrophysics Data System (ADS)

    Cioaca, M. E.; Munteanu, M.

    2012-04-01

    Porphyry copper deposits are the most important source of Cu in the world, but also a source of Mo, Au, Ag and Sn. Some "high-technology elements" (HTE), such as Re, In, W, Te and Se can reach economically-interesting concentrations in this type of deposits. Elevated platinum group elements (Pd and Pt) contents have been reported from several porphyry copper deposits from Balkan Peninsula and Pacific area. In Romania, numerous porphyry copper deposits occur in Banat (Southern Carpathians) and in Apuseni Mountains related to Alpine orogenesis. In Banat, they are classified as Cu-Mo type (Moldova Nouă, Sasca, Şopot, Bozovici, Teregova-Lăpuşnicel) [1] being associated with Laramian granodiorite/monzodiorite bodies of calc-alkaline affinity. The porphyry copper deposits from Apuseni Mountains are hosted mainly by microdiorite subvolcanic bodies and andesites of the Miocene calc-alkaline magmatism and can be divided in three types: Cu-Mo (Au) type (Deva, Roşia Poieni), Cu-Au type (Valea Morii, Bolcana, Rovina, Voia, Tălagiu, Larga, Trâmpoiele, Valea Tisei, Tarniţa) and Au-Cu porphyry (Colnic, Cireşata)[1,3]. The data on HTE of the porphyry-type deposits in Romania are scarce and they come only from a few deposits: Moldova Nouă, Valea Morii, Deva, Bucium-Tarniţa and Rovina [2]. The published contents of HTE in bulk rocks are generally low, but higher values were reported from Cu concentrates (e.g., 500 ppm Se at Deva, 500 ppm Te at Bucium-Tarniţa). There are no data on the platinum group elements contents. The presence of minerals of HTE in some porphyry copper deposits from Romania (e.g., germanium minerals at Bucium-Tarniţa, Roşia Poieni and Rovina) could be an indicator of the enrichment of such elements in the host intrusions. Considering the policy of the European Community towards the identification of new resources of HTE, more systematic investigations of these elements in the porphyry copper deposits of Romania is necessary. A new ongoing project

  20. Sugar Accumulation in Sugarcane

    PubMed Central

    Gayler, K. R.; Glasziou, K. T.

    1972-01-01

    The rate-limiting reaction for glucose uptake in storage tissue of sugarcane, Saccharum officinarum L., appears to be the movement of glucose across the boundary between the free space and the metabolic compartments. The mechanism for uptake of glucose across this boundary has been studied using 3-O-methyl glucose, an analogue of glucose which is not metabolized by sugar-cane tissue. This analogue is taken up by sugarcane storage tissue at a similar rate to glucose. Its rate of uptake follows Michaelis-Menten kinetics, Km = 1.9 mm, and it is competitively inhibited by glucose, Ki = 2 to 3 mm. Glucose uptake is similarly inhibited by 3-O-methyl glucose. Uptake of 3-O-methyl glucose is energy-dependent and does not appear to be the result of counterflow of glucose. It is concluded that glucose and 3-O-methyl glucose uptake across the boundary between the free space and the metabolic compartment in this tissue is mediated by an energy-dependent carrier system capable of accumulating the sugars against a concentration gradient. PMID:16658002

  1. TTX accumulation in pufferfish.

    PubMed

    Noguchi, Tamao; Arakawa, Osamu; Takatani, Tomohiro

    2006-03-01

    Tetrodotoxin (TTX) has been detected in a variety of animals. The finding of TTX in the trumpet shell Charonia sauliae strongly suggested that its origin was its food, a TTX-bearing starfish Astropecten polyacanthus. Since then, the food chain has been consistently implicated as the principal means of TTX intoxication. To identify the primary producer of TTX, intestinal bacteria isolated from several TTX-bearers were investigated for their TTX production. The results demonstrated that some of them could produce TTX. Thus the primary TTX producers in the sea are concluded to be marine bacteria. Subsequently, detritus feeders and zooplankton can be intoxicated with TTX through the food chain, or in conjunction with parasitism or symbiosis. The process followed by small carnivores, omnivores or scavengers, and by organisms higher up the food chain would result in the accumulation of higher concentrations of TTX. Finally, pufferfish at the top of the food chain are intoxicated with TTX. This hypothesis is supported by the fact that net cage and land cultures produce non-toxic pufferfish that can be made toxic by feeding with a TTX-containing diet.

  2. Elemental health

    SciTech Connect

    Tonneson, L.C.

    1997-01-01

    Trace elements used in nutritional supplements and vitamins are discussed in the article. Relevant studies are briefly cited regarding the health effects of selenium, chromium, germanium, silicon, zinc, magnesium, silver, manganese, ruthenium, lithium, and vanadium. The toxicity and food sources are listed for some of the elements. A brief summary is also provided of the nutritional supplements market.

  3. Process development for elemental recovery from PGM tailings by thermochemical treatment: Preliminary major element extraction studies using ammonium sulphate as extracting agent.

    PubMed

    Mohamed, Sameera; van der Merwe, Elizabet M; Altermann, Wladyslaw; Doucet, Frédéric J

    2016-04-01

    Mine tailings can represent untapped secondary resources of non-ferrous, ferrous, precious, rare and trace metals. Continuous research is conducted to identify opportunities for the utilisation of these materials. This preliminary study investigated the possibility of extracting major elements from South African tailings associated with the mining of Platinum Group Metals (PGM) at the Two Rivers mine operations. These PGM tailings typically contain four major elements (11% Al2O3; 12% MgO; 22% Fe2O3; 34% Cr2O3), with lesser amounts of SiO2 (18%) and CaO (2%). Extraction was achieved via thermochemical treatment followed by aqueous dissolution, as an alternative to conventional hydrometallurgical processes. The thermochemical treatment step used ammonium sulphate, a widely available, low-cost, recyclable chemical agent. Quantification of the efficiency of the thermochemical process required the development and optimisation of the dissolution technique. Dissolution in water promoted the formation of secondary iron precipitates, which could be prevented by leaching thermochemically-treated tailings in 0.6M HNO3 solution. The best extraction efficiencies were achieved for aluminium (ca. 60%) and calcium (ca. 80%). 35% iron and 32% silicon were also extracted, alongside chromium (27%) and magnesium (25%). Thermochemical treatment using ammonium sulphate may therefore represent a promising technology for extracting valuable elements from PGM tailings, which could be subsequently converted to value-added products. However, it is not element-selective, and major elements were found to compete with the reagent to form water-soluble sulphate-metal species. Further development of this integrated process, which aims at achieving the full potential of utilisation of PGM tailings, is currently underway.

  4. Comparative physiology of elemental distributions in plants

    PubMed Central

    Conn, Simon; Gilliham, Matthew

    2010-01-01

    Background Plants contain relatively few cell types, each contributing a specialized role in shaping plant function. With respect to plant nutrition, different cell types accumulate certain elements in varying amounts within their storage vacuole. The role and mechanisms underlying cell-specific distribution of elements in plants is poorly understood. Scope The phenomenon of cell-specific elemental accumulation has been briefly reviewed previously, but recent technological advances with the potential to probe mechanisms underlying elemental compartmentation have warranted an updated evaluation. We have taken this opportunity to catalogue many of the studies, and techniques used for, recording cell-specific compartmentation of particular elements. More importantly, we use three case-study elements (Ca, Cd and Na) to highlight the basis of such phenomena in terms of their physiological implications and underpinning mechanisms; we also link such distributions to the expression of known ion or solute transporters. Conclusions Element accumulation patterns are clearly defined by expression of key ion or solute transporters. Although the location of element accumulation is fairly robust, alterations in expression of certain solute transporters, through genetic modifications or by growth under stress, result in perturbations to these patterns. However, redundancy or induced pleiotropic expression effects may complicate attempts to characterize the pathways that lead to cell-specific elemental distribution. Accumulation of one element often has consequences on the accumulation of others, which seems to be driven largely to maintain vacuolar and cytoplasmic osmolarity and charge balance, and also serves as a detoxification mechanism. Altered cell-specific transcriptomics can be shown, in part, to explain some of this compensation. PMID:20410048

  5. Superheavy Elements

    ERIC Educational Resources Information Center

    Tsang, Chin Fu

    1975-01-01

    Discusses the possibility of creating elements with an atomic number of around 114. Describes the underlying physics responsible for the limited extent of the periodic table and enumerates problems that must be overcome in creating a superheavy nucleus. (GS)

  6. Elemental Education.

    ERIC Educational Resources Information Center

    Daniel, Esther Gnanamalar Sarojini; Saat, Rohaida Mohd.

    2001-01-01

    Introduces a learning module integrating three disciplines--physics, chemistry, and biology--and based on four elements: carbon, oxygen, hydrogen, and silicon. Includes atomic model and silicon-based life activities. (YDS)

  7. Noise Reduction by Signal Accumulation

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2006-01-01

    The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the…

  8. Metal accumulation capacity of five species of Sphagnum moss

    SciTech Connect

    Aulio, K.

    1985-10-01

    The present paper describes the first experimental evidence of the species-specific differences in the cation accumulation properties in Sphagnum mosses. Manganese was chosen for the object of the experiments because this element appears to show the greatest variability under natural conditions.

  9. Gypsum accumulation on carbonate stone

    USGS Publications Warehouse

    McGee, E.S.; Mossotti, V.G.

    1992-01-01

    The accumulation of gypsum on carbonate stone has been investigated through exposure of fresh samples of limestone and marble at monitored sites, through examination of alteration crusts from old buildings and through laboratory experiments. Several factors contribute to gypsum accumulation on carbonate stone. Marble or limestone that is sheltered from direct washing by rain in an urban environment with elevated pollution levels is likely to accumulate a gypsum crust. Crust development may be enhanced if the stone is porous or has an irregular surface area. Gypsum crusts are a surficial alteration feature; gypsum crystals form at the pore opening-air interface, where evaporation is greatest.

  10. FUEL ELEMENT

    DOEpatents

    Bean, R.W.

    1963-11-19

    A ceramic fuel element for a nuclear reactor that has improved structural stability as well as improved cooling and fission product retention characteristics is presented. The fuel element includes a plurality of stacked hollow ceramic moderator blocks arranged along a tubular raetallic shroud that encloses a series of axially apertured moderator cylinders spaced inwardly of the shroud. A plurality of ceramic nuclear fuel rods are arranged in the annular space between the shroud and cylinders of moderator and appropriate support means and means for directing gas coolant through the annular space are also provided. (AEC)

  11. Manganese As a Metal Accumulator

    EPA Science Inventory

    Manganese deposits in water distribution systems accumulate metals, radionuclides and oxyanions by a combination of surface complexation, adsorption and solid substitution, as well as a combination of oxidation followed by manganese reduction and sorption of the oxidized constitu...

  12. Element Research.

    ERIC Educational Resources Information Center

    Herald, Christine

    2001-01-01

    Describes a research assignment for 8th grade students on the elements of the periodic table. Students use web-based resources and a chemistry handbook to gather information, construct concept maps, and present the findings to the full class using the mode of their choice: a humorous story, a slideshow or gameboard, a brochure, a song, or skit.…

  13. Mercury, elemental

    Integrated Risk Information System (IRIS)

    Mercury , elemental ; CASRN 7439 - 97 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  14. Superheavy Elements

    NASA Astrophysics Data System (ADS)

    Hofmann, S.

    The nuclear shell model predicts that the next doubly magic shell closure beyond 208Pb is at a proton number Z=114, 120, or 126 and at a neutron number N=172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical `SuperHeavy Elements' (SHEs). Experimental methods have been developed which allowed for the identification of new elements at production rates of one atom per month. Using cold fusion reactions which are based on lead and bismuth targets, relatively neutron-deficient isotopes of the elements from 107 to 113 were synthesized at GSI in Darmstadt, Germany, and/or at RIKEN in Wako, Japan. In hot fusion reactions of 48Ca projectiles with actinide targets more neutron-rich isotopes of the elements from 112 to 116 and even 118 were produced at the Flerov Laboratory of Nuclear Reactions (FLNR) at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. Recently, part of these data which represent the first identification of nuclei located on the predicted island of SHEs were confirmed in two independent experiments. The decay data reveal that for the heaviest elements, the dominant decay mode is α emission rather than fission. Decay properties as well as reaction cross-sections are compared with results of theoretical studies. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques. At a higher sensitivity, the detailed exploration of the region of spherical SHEs will be in the center of interest of future experimental work. New data will certainly challenge theoretical studies on the mechanism of the synthesis, on the nuclear decay properties, and on the chemical behavior of these heaviest atoms at the limit of stability.

  15. Accumulation of artificial radionuclides in agricultural plants in the area used for surface nuclear tests.

    PubMed

    Kozhakhanov, T E; Lukashenko, S N; Larionova, N V

    2014-11-01

    The paper reports on the study of artificial radionuclide accumulation in agricultural crops grown at the territory with high concentration of radionuclides, and first of all - with high concentration of transuranium elements. As a result of this work, peculiarities of accumulation and distribution of artificial radionuclides in the vegetative and generative organs of the studied plants have been revealed. Basic accumulation factors have been found for (137)Cs, (90)Sr, (239+240)Pu, and (241)Am in agricultural products. Accumulation factor dependence on type of planting was found for the investigated types of plants. It has been found that the vegetative organs accumulate radionuclides most of all.

  16. Syntheses and spectroscopic studies of some platinum group metal complexes with oxazepam as ligand

    NASA Astrophysics Data System (ADS)

    Benedetti, Adriano; Preti, Carlo; Tosi, Giuseppe

    1984-05-01

    The preparation and characterization of some rhodium(III), iridium(III), palladium(II) and platinum(II) halide complexes with oxazepam, 7-chloro-1,3-dihydro-5-phenyl-3-hydroxy-2H-1,4-benzodiazepin-2-one are reported. The obtained complexes of the type ML 3X 3 (M = Rh, Ir) and ML 2X 2 (M = Pd, Pt) with the exception of the rhodium and palladium iododerivatives which have 1:6 and 1:4 metal:ligand ratios, respectively, have been studied and characterized through vibrational and electronic spectra, 1H and 13C NMR studies, conductivity measurements and magnetic susceptibility data. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of the crystal field theory and the various parameters have been calculated. The most convincing structural evidence supports an octahedral stereochemistry for the rhodium and iridium derivatives and a square planar geometry for the palladium and platinum compounds with terminal halides and terminal ligands, acting as monodentate only in all the metal complexes through the nitrogen atom in the 4-position.

  17. Tolerance of non-platinum group metals cathodes proton exchange membrane fuel cells to air contaminants

    NASA Astrophysics Data System (ADS)

    Reshetenko, Tatyana; Serov, Alexey; Artyushkova, Kateryna; Matanovic, Ivana; Sarah Stariha; Atanassov, Plamen

    2016-08-01

    The effects of major airborne contaminants (SO2, NO2 and CO) on the spatial performance of Fe/N/C cathode membrane electrode assemblies were studied using a segmented cell system. The injection of 2-10 ppm SO2 in air stream did not cause any performance decrease and redistribution of local currents due to the lack of stably adsorbed SO2 molecules on Fe-Nx sites, as confirmed by density functional theory (DFT) calculations. The introduction of 5-20 ppm of CO into the air stream also did not affect fuel cell performance. The exposure of Fe/N/C cathodes to 2 and 10 ppm NO2 resulted in performance losses of 30 and 70-75 mV, respectively. DFT results showed that the adsorption energies of NO2 and NO were greater than that of O2, which accounted for the observed voltage decrease and slight current redistribution. The cell performance partially recovered when the NO2 injection was stopped. The long-term operation of the fuel cells resulted in cell performance degradation. XPS analyses of Fe/N/C electrodes revealed that the performance decrease was due to catalyst degradation and ionomer oxidation. The latter was accelerated in the presence of air contaminants. The details of the spatial performance and electrochemical impedance spectroscopy results are presented and discussed.

  18. A Novel Non-Platinum Group Electrocatalyst for PEM Fuel Cell Application

    SciTech Connect

    Kim, Jin Yong; Oh, Takkeun; Shin, Yongsoon; Bonnett, Jeff F.; Weil, K. Scott

    2011-04-01

    Precious-metal catalysts (predominantly Pt or Pt-based alloys supported on carbon) have traditionally been used to catalyze the electrode reactions in polymer electrolyte membrane (PEM) fuel cells. However as PEM fuel systems begin to approach commercial reality, there is an impending need to replace Pt with a lower cost alternative. The present study investigates the performance of a carbon-supported tantalum oxide material as a potential oxygen reduction reaction (ORR) catalyst for use on the cathode side of the PEM fuel cell membrane electrode assembly. Although bulk tantalum oxide tends to exhibit poor electrochemical performance due to limited electrical conductivity, it displays a high oxygen reduction potential; one that is comparable to Pt. Analysis of the Pourbaix electrochemical equilibrium database also indicates that tantalum oxide (Ta2O5) is chemically stable under the pH and applied potential conditions to which the cathode catalyst is typically exposed during stack operation. Nanoscale tantalum oxide catalysts were fabricated using two approaches, by reactive oxidation sputtering and by direct chemical synthesis, each carried out on a carbon support material. Nanoscale tantalum oxide particles measuring approximately 6nm in size that were sputtered onto carbon paper exhibited a mass-specific current density as high as one-third that of Pt when measured at 0.6V vs. NHE. However because of the two-dimensional nature of this particle-on-paper structure, which limits the overall length of the triple phase boundary junctions where the oxide, carbon paper, and aqueous electrolyte meet, the corresponding area-specific current density was quite low. The second synthesis approach yielded a more extended, three-dimensional structure via chemical deposition of nanoscale tantalum oxide particles on carbon powder. These catalysts exhibited a high ORR onset potential, comparable to that of Pt, and displayed a significant improvement in the area-specific current density. Overall, the highest mass-specific current density of the carbon-powder supported catalyst was ~ 9% of that of Pt.

  19. Platinum Group Thiophenoxyimine Complexes: Syntheses,Crystallographic and Computational Studies of Structural Properties

    SciTech Connect

    Krinsky, Jamin L.; Arnold, John; Bergman, Robert G.

    2006-10-03

    Monomeric thiosalicylaldiminate complexes of rhodium(I) and iridium(I) were prepared by ligand transfer from the homoleptic zinc(II) species. In the presence of strongly donating ligands, the iridium complexes undergo insertion of the metal into the imine carbon-hydrogen bond. Thiophenoxyketimines were prepared by non-templated reaction of o-mercaptoacetophenone with anilines, and were complexed with rhodium(I), iridium(I), nickel(II) and platinum(II). X-ray crystallographic studies showed that while the thiosalicylaldiminate complexes display planar ligand conformations, those of the thiophenoxyketiminates are strongly distorted. Results of a computational study were consistent with a steric-strain interpretation of the difference in preferred ligand geometries.

  20. Catalytic currents of hydrogen evolution by platinum-group metal mercaptoquinolinates in aqueous-organic media

    SciTech Connect

    Ulakhovich, N.A.; Budnikov, G.K.; Medyantseva, E.P.; Romanova, O.N.; Sturis, A.P.

    1986-06-20

    Coordination compounds of Ru(III), Rh(III), Os(III), and Ir(III) with methyl derivatives of 8-mercaptoquinoline catalyze the evolution of hydrogen on mercury and graphite electrodes in a mixture of DMFA and acetate buffer solution. The catalytic activity of the complexes increases with decreasing acidity of the mercapto group. The proposed scheme of the electrode process includes preprotonation of the original complex with the central atom in the 3+ degree of oxidation.

  1. Assessment of exposure to platinum-group metals in urban children

    NASA Astrophysics Data System (ADS)

    Caroli, S.; Alimonti, A.; Petrucci, F.; Bocca, B.; Krachler, M.; Forastiere, F.; Sacerdote, M. T.; Mallone, S.

    2001-07-01

    Catalytic converters for automotive traction raise some concern for human health and the environment, due to the release of Pd, Pt and Rh (Pt-Group Metals, PGMs). In fact, the thermal and mechanical conditions under which such devices work (including abrasion effects and hot-temperature chemical reactions with oil fumes) can cause significant release of the PGMs to the environment and eventually affect human health. A pilot investigation was performed to assess the exposure to these metals of 310 schoolchildren aged between 6 and 10 years from the urban and suburban area of Rome. All determinations were performed by high-resolution magnetic-sector inductively-coupled plasma-mass spectrometry after UV irradiation of the samples. The mean concentration values of these metals in urine were found to be (in ng/g creatinine) 7.5±5.4 for Pd, 0.9±1.1 for Pt and 8.5±8.0 for Rh. Urine concentrations of Pd and Rh (but not Pt) were found to be strongly associated with traffic density in the area of residence.

  2. Tolerance of non-platinum group metals cathodes proton exchange membrane fuel cells to air contaminants

    NASA Astrophysics Data System (ADS)

    Reshetenko, Tatyana; Serov, Alexey; Artyushkova, Kateryna; Matanovic, Ivana; Sarah Stariha; Atanassov, Plamen

    2016-08-01

    The effects of major airborne contaminants (SO2, NO2 and CO) on the spatial performance of Fe/N/C cathode membrane electrode assemblies were studied using a segmented cell system. The injection of 2-10 ppm SO2 in air stream did not cause any performance decrease and redistribution of local currents due to the lack of stably adsorbed SO2 molecules on Fe-Nx sites, as confirmed by density functional theory (DFT) calculations. The introduction of 5-20 ppm of CO into the air stream also did not affect fuel cell performance. The exposure of Fe/N/C cathodes to 2 and 10 ppm NO2 resulted in performance losses of 30 and 70-75 mV, respectively. DFT results showed that the adsorption energies of NO2 and NO were greater than that of O2, which accounted for the observed voltage decrease and slight current redistribution. The cell performance partially recovered when the NO2 injection was stopped. The long-term operation of the fuel cells resulted in cell performance degradation. XPS analyses of Fe/N/C electrodes revealed that the performance decrease was due to catalyst degradation and ionomer oxidation. The latter was accelerated in the presence of air contaminants. The details of the spatial performance and electrochemical impedance spectroscopy results are presented and discussed.

  3. FUEL ELEMENT

    DOEpatents

    Fortescue, P.; Zumwalt, L.R.

    1961-11-28

    A fuel element was developed for a gas cooled nuclear reactor. The element is constructed in the form of a compacted fuel slug including carbides of fissionable material in some cases with a breeder material carbide and a moderator which slug is disposed in a canning jacket of relatively impermeable moderator material. Such canned fuel slugs are disposed in an elongated shell of moderator having greater gas permeability than the canning material wherefore application of reduced pressure to the space therebetween causes gas diffusing through the exterior shell to sweep fission products from the system. Integral fission product traps and/or exterior traps as well as a fission product monitoring system may be employed therewith. (AEC)

  4. Reducing arsenic accumulation in rice grain through iron oxide amendment.

    PubMed

    Farrow, Eric M; Wang, Jianmin; Burken, Joel G; Shi, Honglan; Yan, Wengui; Yang, John; Hua, Bin; Deng, Baolin

    2015-08-01

    Effects of soil-arsenic (As), phosphorus and iron oxide on As accumulation in rice grain were investigated. Cultivars that have significantly different sensitivity to As, straighthead-resistant Zhe 733 and straighthead-susceptible Cocodrie, were used to represent different cultivar varieties. The grain accumulation of other elements of concern, selenium (Se), molybdenum (Mo), and cadmium (Cd) was also monitored. Results demonstrated that high soil-As not only resulted in high grain-As, but could also result in high grain-Se, and Zhe 733 had significantly less grain-As than Cocodrie did. However, soil-As did not impact grain-Mo and Cd. Among all elements monitored, iron oxide amendment significantly reduced grain-As for both cultivars, while the phosphate application only reduced grain-Se for Zhe 733. Results also indicated that cultivar type significantly impacted grain accumulation of all monitored trace elements. Therefore, applying iron oxide to As-contaminated land, in addition to choosing appropriate rice cultivar, can effectively reduce the grain accumulation of As. PMID:25910688

  5. Geomycology. [fungal biosolubilization and accumulation of metals

    NASA Technical Reports Server (NTRS)

    Puerner, N. J.; Siegel, S. M.

    1976-01-01

    Fungi have long been known to have capabilities for reduction and alkylation of arsenate and selenate but their general capabilities for solubilizing and accumulating metallic substances have been given serious attention only in recent years. Common members of the Aspergillaceae cultured on boron, copper, lead and other metals or oxides can solubilize and concentrate the elements or their compounds. To account for biosolubilization of the metals, we have set up a model study, incubating selected metals, e.g., mercury, in solutions of various metabolites including L-lysine and citric acid. Results of 100-300 days incubation showed that many metals can in fact be readily solubilized, and in some cases more effectively at pH 6-7 than at pH 1.5-2.

  6. Maximum likelihood decoding analysis of Accumulate-Repeat-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    Repeat-Accumulate (RA) codes are the simplest turbo-like codes that achieve good performance. However, they cannot compete with Turbo codes or low-density parity check codes (LDPC) as far as performance is concerned. The Accumulate Repeat Accumulate (ARA) codes, as a subclass of LDPC codes, are obtained by adding a pre-coder in front of RA codes with puncturing where an accumulator is chosen as a precoder. These codes not only are very simple, but also achieve excellent performance with iterative decoding. In this paper, the performance of these codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. The weight distribution of some simple ARA codes is obtained, and through existing tightest bounds we have shown the ML SNR threshold of ARA codes approaches very closely to the performance of random codes. We have shown that the use of precoder improves the SNR threshold but interleaving gain remains unchanged with respect to RA code with puncturing.

  7. FUEL ELEMENT

    DOEpatents

    Howard, R.C.; Bokros, J.C.

    1962-03-01

    A fueled matrlx eontnwinlng uncomblned carbon is deslgned for use in graphlte-moderated gas-cooled reactors designed for operatlon at temperatures (about 1500 deg F) at which conventional metallic cladding would ordlnarily undergo undesired carburization or physical degeneratlon. - The invention comprlses, broadly a fuel body containlng uncombined earbon, clad with a nickel alloy contalning over about 28 percent by' weight copper in the preferred embodlment. Thls element ls supporirted in the passageways in close tolerance with the walls of unclad graphite moderator materlal. (AEC)

  8. Radiocesium accumulation properties of Chengiopanax sciadophylloides.

    PubMed

    Sugiura, Yuki; Kanasashi, Tsutomu; Ogata, Yoshimune; Ozawa, Hajime; Takenaka, Chisato

    2016-01-01

    Through the assessments of radioactive contamination after the Fukushima Dai-ichi Nuclear Power Plant (F1NPP) accident, it has been reported that some sprouts of Chengiopanax sciadophylloides (Franch. et Sav.) at the site contained radiocesium (((134),)(137)Cs) at higher concentrations than the other plants. To assess the phytoremediation properties of C. sciadophylloides for (137)Cs decontamination, we aimed to quantify the (137)Cs accumulation in C. sciadophylloides. We measured the (137)Cs concentrations in various organs of C. sciadophylloides collected from the forest in the town of Kawamata, Fukushima prefecture, together with the concentrations of other elements [potassium (K), rubidium, (133)Cs, calcium, strontium, and manganese] present. In addition, we compared the foliar concentrations of these elements in C. sciadophylloides with those in four different deciduous tree species. The mean of foliar (137)Cs concentration in C. sciadophylloides was 28.1 kBq kg(-1) DW, one order of magnitude higher than that found in the other species. The (137)Cs concentrations were in the order of leaves > bark > wood. The wood of the treetop, leaf scars, and roots contained higher amounts of (137)Cs than that of the trunk. From the distribution of (137)Cs in C. sciadophylloides, we confirmed that (137)Cs tends to accumulate in the young growing parts. The difference in the distribution of (137)Cs and (133)Cs indicated that surface uptake of (137)Cs occurs. A significant correlation between K and (137)Cs concentrations in each organ was found, which suggested that (137)Cs in the plant body is transferred through the same pathway as K. On the other hand, there was no correlation between foliar K and (137)Cs concentrations, implying that the uptake ratio of K to (137)Cs was different for each individual. To determine the factors driving specific (137)Cs accumulation and/or the variability of the ratio between K and (137)Cs, the distribution of (137)Cs and the root in soil

  9. Radiocesium accumulation properties of Chengiopanax sciadophylloides.

    PubMed

    Sugiura, Yuki; Kanasashi, Tsutomu; Ogata, Yoshimune; Ozawa, Hajime; Takenaka, Chisato

    2016-01-01

    Through the assessments of radioactive contamination after the Fukushima Dai-ichi Nuclear Power Plant (F1NPP) accident, it has been reported that some sprouts of Chengiopanax sciadophylloides (Franch. et Sav.) at the site contained radiocesium (((134),)(137)Cs) at higher concentrations than the other plants. To assess the phytoremediation properties of C. sciadophylloides for (137)Cs decontamination, we aimed to quantify the (137)Cs accumulation in C. sciadophylloides. We measured the (137)Cs concentrations in various organs of C. sciadophylloides collected from the forest in the town of Kawamata, Fukushima prefecture, together with the concentrations of other elements [potassium (K), rubidium, (133)Cs, calcium, strontium, and manganese] present. In addition, we compared the foliar concentrations of these elements in C. sciadophylloides with those in four different deciduous tree species. The mean of foliar (137)Cs concentration in C. sciadophylloides was 28.1 kBq kg(-1) DW, one order of magnitude higher than that found in the other species. The (137)Cs concentrations were in the order of leaves > bark > wood. The wood of the treetop, leaf scars, and roots contained higher amounts of (137)Cs than that of the trunk. From the distribution of (137)Cs in C. sciadophylloides, we confirmed that (137)Cs tends to accumulate in the young growing parts. The difference in the distribution of (137)Cs and (133)Cs indicated that surface uptake of (137)Cs occurs. A significant correlation between K and (137)Cs concentrations in each organ was found, which suggested that (137)Cs in the plant body is transferred through the same pathway as K. On the other hand, there was no correlation between foliar K and (137)Cs concentrations, implying that the uptake ratio of K to (137)Cs was different for each individual. To determine the factors driving specific (137)Cs accumulation and/or the variability of the ratio between K and (137)Cs, the distribution of (137)Cs and the root in soil

  10. Pensions and Household Wealth Accumulation

    ERIC Educational Resources Information Center

    Engelhardt, Gary V.; Kumar, Anil

    2011-01-01

    Economists have long suggested that higher private pension benefits "crowd out" other sources of household wealth accumulation. We exploit detailed information on pensions and lifetime earnings for older workers in the 1992 wave of the Health and Retirement Study and employ an instrumental-variable (IV) identification strategy to estimate…

  11. Temporal and spatial studies of autocatalyst-derived platinum, rhodium, and palladium and selected vehicle-derived trace elements in the environment.

    PubMed

    Jarvis, K E; Parry, S J; Piper, J M

    2001-03-15

    The distribution of platinum, rhodium, and palladium (platinum-group elements; PGEs) adjacent to two major U.K. roads shows a rapid decrease (more than 1 order of magnitude) away from the road and reflects patterns shown by other traffic-derived trace elements such as Pb and Zn. However, ratios of Pt:Rh remain relatively constant from 0 to 10 m distance, suggesting that at least some of the PGEs are transported away from the source. A temporal study over a 12-month period, of road dust and surface samples, reveals elevated concentrations above background levels, with maximum values of Pt >500 ng g(-1), Rh 70 ng g(-1), and Pd 70 ng g(-1). Concentrations vary considerably throughout the year and show some tentative correlation with rainfall. Element speciation, an essential control on mobility and hence distribution, was investigated, and the results of solubility experiments show that up to 30% of the Pd present dissolves in acid solutions. This indicates that at least some of the Pd is present in a soluble form and is therefore potentially highly mobile.

  12. Trace element and isotope geochemistry of Cretaceous-Tertiary boundary sediments: identification of extra-terrestrial and volcanic components

    NASA Technical Reports Server (NTRS)

    Margolis, S. V.; Doehne, E. F.

    1988-01-01

    Trace element and stable isotope analyses were performed on a series of sediment samples crossing the Cretaceous-Tertiary (K-T) boundary from critical sections at Aumaya and Sopelano, Spain. The aim is to possibly distinguish extraterrestrial vs. volcanic or authigenic concentration of platinum group and other elements in K-T boundary transitional sediments. These sediments also have been shown to contain evidence for step-wise extinction of several groups of marine invertebrates, associated with negative oxygen and carbon isotope excursions occurring during the last million years of the Cretaceous. These isotope excursions have been interpreted to indicate major changes in ocean thermal regime, circulation, and ecosystems that may be related to multiple events during latest Cretaceous time. Results to date on the petrographic and geochemical analyses of the Late Cretaceous and Early Paleocene sediments indicate that diagenesis has obviously affected the trace element geochemistry and stable isotope compositions at Zumaya. Mineralogical and geochemical analysis of K-T boundary sediments at Zumaya suggest that a substantial fraction of anomalous trace elements in the boundary marl are present in specific mineral phases. Platinum and nickel grains perhaps represent the first direct evidence of siderophile-rich minerals at the boundary. The presence of spinels and Ni-rich particles as inclusions in aluminosilicate spherules from Zumaya suggests an original, non-diagenetic origin for the spherules. Similar spherules from southern Spain (Caravaca), show a strong marine authigenic overprint. This research represents a new approach in trying to directly identify the sedimentary mineral components that are responsible for the trace element concentrations associated with the K-T boundary.

  13. Chromoplast biogenesis and carotenoid accumulation.

    PubMed

    Li, Li; Yuan, Hui

    2013-11-15

    Chromoplasts are special organelles that possess superior ability to synthesize and store massive amounts of carotenoids. They are responsible for the distinctive colors found in fruits, flowers, and roots. Chromoplasts exhibit various morphologies and are derived from either pre-existing chloroplasts or other non-photosynthetic plastids such as proplastids, leucoplasts or amyloplasts. While little is known about the molecular mechanisms underlying chromoplast biogenesis, research progress along with proteomics study of chromoplast proteomes signifies various processes and factors important for chromoplast differentiation and development. Chromoplasts act as a metabolic sink that enables great biosynthesis and high storage capacity of carotenoids. The formation of chromoplasts enhances carotenoid metabolic sink strength and controls carotenoid accumulation in plants. The objective of this review is to provide an integrated view on our understanding of chromoplast biogenesis and carotenoid accumulation in plants.

  14. Mechanisms of intrahepatic triglyceride accumulation

    PubMed Central

    Ress, Claudia; Kaser, Susanne

    2016-01-01

    Hepatic steatosis defined as lipid accumulation in hepatocytes is very frequently found in adults and obese adolescents in the Western World. Etiologically, obesity and associated insulin resistance or excess alcohol intake are the most frequent causes of hepatic steatosis. However, steatosis also often occurs with chronic hepatitis C virus (HCV) infection and is also found in rare but potentially life-threatening liver diseases of pregnancy. Clinical significance and outcome of hepatic triglyceride accumulation are highly dependent on etiology and histological pattern of steatosis. This review summarizes current concepts of pathophysiology of common causes of hepatic steatosis, including non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease, chronic HCV infections, drug-induced forms of hepatic steatosis, and acute fatty liver of pregnancy. Regarding the pathophysiology of NAFLD, this work focuses on the close correlation between insulin resistance and hepatic triglyceride accumulation, highlighting the potential harmful effects of systemic insulin resistance on hepatic metabolism of fatty acids on the one side and the role of lipid intermediates on insulin signalling on the other side. Current studies on lipid droplet morphogenesis have identified novel candidate proteins and enzymes in NAFLD. PMID:26819531

  15. Identification of putative silicon transporters in the low accumulators N. tabacum and S. lycopersicum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silicon (Si) has long been excluded from the list of essential elements based on a definition developed over 60 years ago. However, how can one deem an element “non-essential” if through millennia of adaptation a fundamental pathway of perception and accumulation leading to molecular changes within...

  16. Tolerance and accumulation of cesium and strontium in saprothophic fungi

    NASA Astrophysics Data System (ADS)

    Seeprasert, P.; Yoneda, M.; Shimada, Y.; Matsui, Y.

    2015-05-01

    Soil contamination by nuclear accidents has led to a resurgence of interest in microbe-radionuclide interactions. Soil fungi accumulate radioactive elements from contaminated soil, and it has been hypothesized that this may alter the availability of radionuclides to plants and alter their movement in particular areas. This study intended to demonstrate how soil saprotrophic fungi accumulated Cs and Sr isotopes in both stable and radioactive solution forms. An experiment to determine the tolerance of fungal growth under extremely inhibitory concentrations of Cs and Sr stable isotopes was conducted. The results showed that fungal cells were more sensitive to Cs than to Sr. Accumulations of Cs and Sr were examined through sorption mechanisms using resting cells in the solutions under various conditions. The sorption capacity was indirectly determined by analysing the elements, which decreased in the solution. The equilibrium data were fitted with sorption isotherms to show the best fit with the Langmuir isotherm for both elements, assuming that the sorption sites form a surface monolayer. In addition, pH was examined to investigate its effect on the sorption capacity of Cs and Sr.

  17. Removal and accumulation of As, Cd and Cr by Typha latifolia.

    PubMed

    Leura-Vicencio, Adriana; Alonso-Castro, Angel Josabad; Carranza-Álvarez, Candy; Loredo-Portales, René; Alfaro-De la Torre, Ma Catalina; García-De la Cruz, Ramón Fernando

    2013-06-01

    The removal from the solution and the accumulation of As, Cd and Cr by Typha latifolia was studied. Small plants of T. latifolia, collected from a non-contaminated site, were exposed to individual concentrations of As, Cd and Cr for 10 days. The ability of T. latifolia for the removal of toxic elements ranged from 23% to 54% for As, 43%-55% for Cd and 28%-73% for Cr. The accumulation of toxic elements in T. latifolia occurred mainly in the roots. The results suggest that T. latifolia can be considered as an interesting alternative for treating aquatic effluents polluted with toxic trace elements.

  18. Siderophile elements in brecciated HED meteorites and the nature of projectile materials in HED meteorites

    NASA Astrophysics Data System (ADS)

    Shirai, N.; Okamoto, C.; Yamaguchi, A.; Ebihara, M.

    2016-03-01

    Petrological, mineralogical and geochemical studies were performed on five brecciated HED meteorites (ALH 76005, EET 92003, LEW 85300, LEW 87026 and GRO 95633) in order to elucidate the nature of impactors on the HED parent body. Some brecciated HED meteorites contain exotic materials such as FeNi-metal grains with low Co/Ni ratios (ALH 76005, EET 92003 and GRO 95633) and carbonaceous chondrite clasts (LEW 85300) in a clastic and/or impact melt matrix. Such exotic materials were incorporated during brecciation. Platinum group element (PGE) abundances vary significantly (CI × 0.002-0.05), but are higher than those of pristine rocks from the HED parent body. The PGE ratios for the five HED meteorites are inconsistent with each other, implying that the impactor components of each HED meteorites are different from each other. The various PGE ratios are consistent with those for metals from chondrites and iron meteorites, and carbonaceous chondrites. This study provides the evidence that IAB and IVA iron meteorites, and carbonaceous chondrites (CM, CO, CV, CK, CB and CR), ordinary chondrites (L and H) and enstatite chondrite (EL) are candidates of the impactor materials on the HED parent body. It is highly probable that significant amounts of siderophile elements were incorporated into the inner solar system objects like the HED parent body from both chondritic materials and differentiated materials like iron meteorites during heavy bombardment. The HED meteorites in this study and metals from mesosiderite have different Pd/Ir ratios, probably implying that HED meteorites and mesosiderites formed either at distinct settings on one common parent body or on similar parent bodies.

  19. A CRITICAL ASSESSMENT OF ELEMENTAL MERCURY AIR/WATER EXCHANGE PARTNERS

    EPA Science Inventory

    Although evasion of elemental mercury from aquatic systems can significantly deplete net mercury accumulation resulting from atmospheric deposition, the current ability to model elemental mercury air/water exchange is limited by uncertainties in our understanding of all gaseous a...

  20. Comparison between the accumulation capacity of four lichen species transplanted to a urban site.

    PubMed

    Bergamaschi, L; Rizzio, E; Giaveri, G; Loppi, S; Gallorini, M

    2007-07-01

    The capacity to accumulate trace elements from the atmosphere of the lichens Hypogymnia physodes, Parmelia sulcata, Pseudevernia furfuracea and Usnea gr. hirta transplanted to an urban site of N Italy was compared. Twenty-nine elements (Al, As, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hg, I, K, La, Mg, Mn, Ni, Pb, Rb, Sb, Sc, Se, Sm, Th, Ti, V, Zn) were analyzed by Instrumental Neutron Activation Analysis (INAA) and Electro-Thermal Atomic Absorption Spectroscopy (ET-AAS). The ratio between the concentrations of each element in exposed samples to that of control samples (exposed-to-control ratio and EC ratio) was used to investigate the accumulation rates of lichen thalli. The results showed that in general elements did not exhibit well defined trends, but rather showed fluctuations, and indicated that H. physodes, P. furfuracea and U. gr. hirta have a similar accumulation capacity, while that of P. sulcata is lower.

  1. Accumulation of contaminants in fish from wastewater treatment wetlands

    USGS Publications Warehouse

    Barber, L.B.; Keefe, S.H.; Antweiler, R.C.; Taylor, H.E.; Wass, R.D.

    2006-01-01

    Increasing demands on water resources in arid environments make reclamation and reuse of municipal wastewater an important component of the water budget. Treatment wetlands can be an integral part of the water-reuse cycle providing both water-quality enhancement and habitat functions. When used for habitat, the bioaccumulation potential of contaminants in the wastewater is a critical consideration. Water and fish samples collected from the Tres Rios Demonstration Constructed Wetlands near Phoenix, Arizona, which uses secondary-treated wastewater to maintain an aquatic ecosystem in a desert environment, were analyzed for hydrophobic organic compounds (HOC) and trace elements. Semipermeable membrane devices (SPMD) were deployed to investigate uptake of HOC. The wetlands effectively removed HOC, and concentrations of herbicides, pesticides, and organic wastewater contaminants decreased 40-99% between inlet and outlet. Analysis of Tilapia mossambica and Gambusia affinis indicated accumulation of HOC, including p,p???-DDE and trans-nonachlor. The SPMD accumulated the HOC detected in the fish tissue as well as additional compounds. Trace-element concentrations in whole-fish tissue were highly variable, but were similar between the two species. Concentrations of HOC and trace elements varied in different fish tissue compartments, and concentrations in Tilapia liver tissue were greater than those in the whole organism or filet tissue. Bioconcentration factors for the trace elements ranged from 5 to 58 000 and for the HOC ranged from 530 to 150 000. ?? 2006 American Chemical Society.

  2. Neurodegeneration with brain iron accumulation (NBIA)

    MedlinePlus

    ... gov/ency/article/001225.htm Neurodegeneration with brain iron accumulation (NBIA) To use the sharing features on this page, please enable JavaScript. Neurodegeneration with brain iron accumulation (formerly known as Hallervorden-Spatz disease) is ...

  3. PIXE micro-mapping of minor elements in Hypatia, a diamond bearing carbonaceous stone from the Libyan Desert Glass area, Egypt: Inheritance from a cold molecular cloud?

    NASA Astrophysics Data System (ADS)

    Andreoli, M. A. G.; Przybylowicz, W. J.; Kramers, J.; Belyanin, G.; Westraadt, J.; Bamford, M.; Mesjasz-Przybylowicz, J.; Venter, A.

    2015-11-01

    Matter originating from space, particularly if it represents rare meteorite samples, is ideally suited to be studied by Particle Induced X-ray Emission (PIXE) as this analytical technique covers a broad range of trace elements and is per se non-destructive. We describe and interpret a set of micro-PIXE elemental maps obtained on two minute (weighing about 25 and 150 mg), highly polished fragments taken from Hypatia, a controversial, diamond-bearing carbonaceous pebble from the SW Egyptian desert. PIXE data show that Hypatia is chemically heterogeneous, with significant amounts of primordial S, Cl, P and at least 10 elements with Z > 21 (Ti, V, Cr, Mn, Fe, Ni, Os, Ir) locally attaining concentrations above 500 ppm. Si, Al, Ca, K, O also occur, but are predominantly confined to cracks and likely represent contamination from the desert environment. Unusual in the stone is poor correlation between elements within the chalcophile (S vs. Cu, Zn) and siderophile (i.e.: Fe vs. Ni, Ir, Os) groups, whereas other siderophiles (Mn, Mo and the Platinum group elements (PGEs)) mimic the distribution of lithophile elements such as Cr and V. Worthy of mention is also the presence of a globular domain (Ø ∼ 120 μm) that is C and metals-depleted, yet Cl (P)-enriched (>3 wt.% and 0.15 wt.% respectively). While the host of the Cl remains undetermined, this chemical unit is enclosed within a broader domain that is similarly C-poor, yet Cr-Ir rich (up to 1.2 and 0.3 wt.% respectively). Our data suggest that the pebble consists of shock-compacted, primitive carbonaceous material enriched in cold, pre-solar dust.

  4. Significant silicon accumulation by marine picocyanobacteria

    NASA Astrophysics Data System (ADS)

    Baines, Stephen B.; Twining, Benjamin S.; Brzezinski, Mark A.; Krause, Jeffrey W.; Vogt, Stefan; Assael, Dylan; McDaniel, Hannah

    2012-12-01

    The marine silicon cycle is thought to be intimately tied to the carbon cycle through its effect on the growth of diatoms. These unicellular algae form substantial blooms in cold, nutrient-rich waters. Their dense, siliceous cell walls promote the sinking of particulate matter, and all the carbon and nutrients contained therein. As such, diatoms are thought to be the primary organisms responsible for the low levels of dissolved silicon observed in the surface ocean and the export of mineral silica to depth. Here, we use synchrotron X-ray fluorescence microscopy to determine the elemental composition of individual diatoms and cyanobacterial cells from the eastern equatorial Pacific and the Sargasso Sea. We show that cells of Synechococcus, a small unicellular marine cyanobacterium that dominates in nutrient-depleted waters, can exhibit cellular ratios of silicon to sulphur, and silicon to phosphorus, approaching those detected in diatoms in the same location. Silicon accumulation was also observed in cultured Synechococcus strains. We estimate that the water column inventory of silicon in Synechococcus can exceed that of diatoms in some cases. We suggest that picocyanobacteria may exert a previously unrecognized influence on the oceanic silicon cycle, especially in nutrient-poor waters.

  5. Trace Elements in River Waters

    NASA Astrophysics Data System (ADS)

    Gaillardet, J.; Viers, J.; Dupré, B.

    2003-12-01

    Trace elements are characterized by concentrations lower than 1 mg L-1 in natural waters. This means that trace elements are not considered when "total dissolved solids" are calculated in rivers, lakes, or groundwaters, because their combined mass is not significant compared to the sum of Na+, K+, Ca2+, Mg2+, H4SiO4, HCO3-, CO32-, SO42-, Cl-, and NO3-. Therefore, most of the elements, except about ten of them, occur at trace levels in natural waters. Being trace elements in natural waters does not necessarily qualify them as trace elements in rocks. For example, aluminum, iron, and titanium are major elements in rocks, but they occur as trace elements in waters, due to their low mobility at the Earth's surface. Conversely, trace elements in rocks such as chlorine and carbon are major elements in waters.The geochemistry of trace elements in river waters, like that of groundwater and seawater, is receiving increasing attention. This growing interest is clearly triggered by the technical advances made in the determination of concentrations at lower levels in water. In particular, the development of inductively coupled plasma mass spectrometry (ICP-MS) has considerably improved our knowledge of trace-element levels in waters since the early 1990s. ICP-MS provides the capability of determining trace elements having isotopes of interest for geochemical dating or tracing, even where their dissolved concentrations are extremely low.The determination of trace elements in natural waters is motivated by a number of issues. Although rare, trace elements in natural systems can play a major role in hydrosystems. This is particularly evident for toxic elements such as aluminum, whose concentrations are related to the abundance of fish in rivers. Many trace elements have been exploited from natural accumulation sites and used over thousands of years by human activities. Trace elements are therefore highly sensitive indexes of human impact from local to global scale. Pollution

  6. Fractionation of highly siderophile and chalcogen elements in components of EH3 chondrites

    NASA Astrophysics Data System (ADS)

    Kadlag, Yogita; Becker, Harry

    2015-07-01

    Abundances of highly siderophile elements (HSE: Re, platinum group elements and Au), chalcogens (Te, Se and S), 187Os/188Os and the major and minor elements Mg, Ca, Mn, Fe, Ni and Co were determined in the components of Sahara 97072 (EH3, find) and Kota Kota (EH3, find) in order to understand the element fractionation processes. In a 187Re-187Os isochron diagram, most magnetic components lie close to the 4.56 Ga IIIA iron meteorite isochron, whereas most other components show deviations from the isochron caused by late redistribution of Re, presumably during terrestrial weathering. Metal- and sulfide rich magnetic fractions and metal-sulfide nodules are responsible for the higher 187Os/188Os in bulk rocks of EH chondrites compared to CI chondrites. The HSE and chalcogens are enriched in magnetic fractions relative to slightly magnetic and nonmagnetic fractions and bulk compositions, indicating that Fe-Ni metal is the main host phase of the HSE in enstatite chondrites. HSE abundance patterns indicate mixing of two components, a CI chondrite like end member and an Au-enriched end member. Because of the decoupled variations of Au from those of Pd or the chalcogens, the enrichment of Au in EH metal cannot be due to metal-sulfide-silicate partitioning processes. Metal and sulfide rich nodules may have formed by melting and reaction of pre-existing refractory element rich material with volatile rich gas. A complex condensation and evaporation history is required to account for the depletion of elements having very different volatility than Au in EH chondrites. The depletions of Te relative to HSE, Se and S in bulk EH chondrites are mainly caused by the depletion of Te in metal. S/Se and S/Mn are lower than in CI chondrites in almost all components and predominantly reflect volatility-controlled loss of sulfur. The latter most likely occurred during thermal processing of dust in the solar nebula (e.g., during chondrule formation), followed by the non-systematic loss of S

  7. Influence of cadmium on PCB congener accumulation in quail

    SciTech Connect

    Leonzio, C.; Marsili, L.; Focardi, S. )

    1992-11-01

    Technological development this century has led to an environmental input of synthetic chemical compounds totally extraneous to natural ecosystems such as Polychlorobiphenyls (PCBs), extensively used in agriculture and industry. These xenobiotics have a high fat/water repartition coefficient, making them easily accumulated by living organisms. Their persistence and low degradability means that they are now present throughout the global ecosystem. Ubiquitous environmental contaminants also include heavy metals like Hg, As, Pb, Cd and Cr, of which Cd, an element causing functional damage to the kidney and liver in which it preferentially accumulates, is of special ecotoxicological importance. The WHO has defined an accumulation of 60 mg/kg (fresh weight), beyond which damage occurs. Cd occurs [open quotes]naturally[close quotes] in high concentrations in certain animal species including molluscs. Birds and marine mammals feeding largely on cephalopods show high levels of this metal. Many monitoring studies have also revealed high concentrations of PCBs in the same animals. The vast majority of studies on contaminants in experimental animals consider the short-, medium- and long-term effects of a single pollutant. However, the presence of synergisms and antagonisms between compounds makes it necessary to adopt a more holistic approach to the problem of environmental pollution. In order to understand if the effect of xenobiotic compounds like PCBs may be potentiated by the natural presence of cadmium in bird population, we sought preliminary information on how the presence of cadmium in the diet may influence the accumulation and metabolization of PCB congeners. The influence of Cd on PCB accumulation was investigated in Japanese quail treated experimentally with Cd and PCBs. Particular attention was paid to final congener accumulation and qualitative differences in congener composition between controls and treated birds. 15 refs., 3 figs., 1 tab.

  8. Ectoine accumulation in Brevibacterium epidermis.

    PubMed

    Onraedt, Annelies; De Muynck, Cassandra; Walcarius, Bart; Soetaert, Wim; Vandamme, Erick

    2004-10-01

    As a halotolerant bacterial species, Brevibacterium epidermis DSM 20659 can grow at relatively high salinity, tolerating up to 2 M NaCl. It synthesizes ectoine and the intracellular content increases with the medium salinity, with a maximum of 0.14 g ectoine/g CDW at 1 M NaCl. Sugar-stressed cells do not synthesize ectoine. Ectoine synthesis is also affected by the presence of external osmolytes. Added betaine is taken up and completely replaced ectoine, while L-proline is only temporarily accumulated after which ectoine is synthesized. The strain can metabolize ectoine; L-glutamate is a better carbon source for ectoine synthesis than L-aspartate.

  9. Accumulation and phytotoxicity of engineered nanoparticles to Cucurbita pepo.

    PubMed

    Hawthorne, Joseph; Musante, Craig; Sinha, Saion K; White, Jason C

    2012-04-01

    The effect of bulk and engineered nanoparticle (NP) Ag, Au, Cu, Si, and C at 250 and 750 mg/L on zucchini biomass, transpiration, and element content was determined. The pH of bulk and NP solutions prior to plant growth frequently differed. Nanoparticle Cu solution pH was significantly higher than bulk Cu, whereas for Ag and C, the NPs had significantly lower pH. Plants were unaffected by Au, regardless of particle size or concentration. NP Ag reduced plant biomass and transpiration by 49-91% compared to equivalent bulk Ag. NP Si at 750 mg/L reduced plant growth and transpiration by 30-51% relative to bulk Si. Bulk and NP Cu were phytotoxic but much of the effect was alleviated by humic acid. The shoot Ag and Cu content did not differ based on particle size or concentration. The accumulation of bulk Au was greater than the NP, but humic acid increased the accumulation of NP and bulk Au by 5.6-fold and 80%, respectively. The uptake of NP Si was 5.6-6.5-fold greater than observed with the bulk element. These findings show that the NPs may have unique phytotoxicity or accumulation patterns and that solution properties can significantly impact particle fate and effects. PMID:22567722

  10. Accumulation and phytotoxicity of engineered nanoparticles to Cucurbita pepo.

    PubMed

    Hawthorne, Joseph; Musante, Craig; Sinha, Saion K; White, Jason C

    2012-04-01

    The effect of bulk and engineered nanoparticle (NP) Ag, Au, Cu, Si, and C at 250 and 750 mg/L on zucchini biomass, transpiration, and element content was determined. The pH of bulk and NP solutions prior to plant growth frequently differed. Nanoparticle Cu solution pH was significantly higher than bulk Cu, whereas for Ag and C, the NPs had significantly lower pH. Plants were unaffected by Au, regardless of particle size or concentration. NP Ag reduced plant biomass and transpiration by 49-91% compared to equivalent bulk Ag. NP Si at 750 mg/L reduced plant growth and transpiration by 30-51% relative to bulk Si. Bulk and NP Cu were phytotoxic but much of the effect was alleviated by humic acid. The shoot Ag and Cu content did not differ based on particle size or concentration. The accumulation of bulk Au was greater than the NP, but humic acid increased the accumulation of NP and bulk Au by 5.6-fold and 80%, respectively. The uptake of NP Si was 5.6-6.5-fold greater than observed with the bulk element. These findings show that the NPs may have unique phytotoxicity or accumulation patterns and that solution properties can significantly impact particle fate and effects.

  11. Potential source regions of dust accumulated in northern Africa

    NASA Astrophysics Data System (ADS)

    Wasowska, S.; Woronko, B.

    2012-04-01

    Sahara is the largest source of the dust in the world. The material sampled from dust storms in Tunisia (Nefta Oasis, El Kantoui Harbor), north Egypt (Alexandria) and Morocco (Mhamid Oasis) (March 2001, March and April 2009) was taken to identify the potential sources of dust accumulation and transport paths in North Africa. The samples were analyzed on grain size, micromorphology of silt grain surfaces in Scanning Electron Microscope (SEM), elemental composition of grains and their surface crusts, loss on ignition, mineralogical composition of samples and carbonate content. Additionally the meteorological situation was analyzed during the dust storm occurrences and preceding periods. The results of grain size analyses show that all studied sediments belong to the small dust type, and dust accumulated in Mhamid is the clay mineral agglomerated (CMA) dust. The source of the CMA are the old dry lake beds. Dust particles are mobilized as aggregates of clay minerals, what is controlled by structure (particle packing) of the original lake sediment, and accumulation is dry and wet as well. The results of the analysis of the quartz grain surface micromorphology, the elemental composition and loss on ignition indicate that dust accumulated in Morocco originated from a relatively homogenous sediment source and, on the other hand, dust found in Alexandria comes from a diversified source. Dust sampled in Tunisia is characterized by the highest content of carbonates and organic matter which suggests the intensive dispelling acting on the weathered material from carbonate rocks and local Mediterranean soil covers rich in CaCO3. The analyses of meteorological conditions during the dust storms and the analyses of the textural characteristics of deposits show that it is highly probable that analysed aeolian dust was transported both for shorter and longer distances. Hypothetic source areas of dust accumulated in Mhamid could be the old ergs, some located 300-500 km away like

  12. Guidelines for Waste Accumulation Areas (WAAs)

    SciTech Connect

    Not Available

    1991-07-01

    The purpose of this document is to set conditions for establishing and maintaining areas for the accumulation of hazardous waste at LBL. Areas designed for accumulation of these wastes in quantities greater than 100 kg (220 lb) per month of solid waste or 55 gallons per month of liquid waste are called Waste Accumulation Areas (WAAs). Areas designed for accumulation of wastes in smaller amounts are called Satellite Accumulation Areas (SAAs). This document provides guidelines for employee and organizational responsibilities for WAAs; constructing a WAA; storing waste in a WAA; operating and maintaining a WAA, and responding to spills in a WAA. 4 figs.

  13. Spatial analysis and indicator building for metal accumulation in mosses.

    PubMed

    Schröder, Winfried; Pesch, Roland

    2004-11-01

    Mosses are used as passive accumulation monitors for metal accumulation in terrestrial ecosystems. Under leadership of the Federal Agency for Environmental Protection Germany took part in the previous European-wide moss monitoring campaigns 1990, 1995 and 2000. The investigations accomplished thereby cannot be presented completely in this article. The remarks rather concentrate on methodical aspects of the statistical data analysis. In Chapter 2 the design of data collection is summarized. Chapter 3 treats the geostatistical analysis and transformation of point data to areal information. Chapter 4 describes the aggregation of the element-specific metal concentrations in mosses to a spatially and temporally differentiated indicator of metal accumulation by means of descriptive and multivariate statistics. The work presented is only a small part of geostatistics and multivariate statistics which fit for analysis of moss monitoring data. Taking the results presented here as a basis, the following steps would further be of great importance: cluster-analytic evaluation of the results of the Moss Monitoring 1990 and 1995, detailing the cluster results using additional empirical and location describing information (e.g. moss species, ecoregions, site and species specific variability of metal accumulation) as well as optimizing the indicator buildung by testing of multivariate statistical regression models (e.g. Classification and Regression Trees). PMID:15473533

  14. Boat detection using vector accumulation of particle motion

    NASA Astrophysics Data System (ADS)

    Zhang, Xuguang; Li, Na; Li, Youyi; Li, Xiaoli

    2014-11-01

    Recently, target detection in sea environment such as boat detection has become a popular research topic which is significant for marine vessels monitoring system. Many target detection methods have been widely applied to practical applications such as frame difference, traditional optical flow and background subtraction method. However, the existing target detection methods are not suitable to deal with the complex conditions of sea surface, such as irregular movement of the waves and illumination changes. In this paper, we developed an approach based on vector accumulation of particle motion mainly aiming at eliminating the effects of irregular movement of waves. Our proposed method applies vector accumulation of particle motion to optical flow field to obtain more accurate detection results under complex conditions. Firstly, the traditional optical flow method is used to acquire motion vector of every particle. Furthermore, the vectors of each flow point are abstracted to represent the recording of a fluid element in the flow over a certain period, succeeding is the accumulation of particle vectors. Finally, we calculate the mean of the vector accumulation to eliminate the effects of irregular movement of waves based on the video. Experimental results show the proposed method can gain better performance than traditional optical flow method.

  15. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases.

    PubMed

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K G; Wiegand, Simone

    2016-04-19

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007)Proc Natl Acad Sci USA104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ∼85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of[Formula: see text]wt % that is typical for concentrations in shallow lakes on early Earth. PMID:27044100

  16. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases.

    PubMed

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K G; Wiegand, Simone

    2016-04-19

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007)Proc Natl Acad Sci USA104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ∼85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of[Formula: see text]wt % that is typical for concentrations in shallow lakes on early Earth.

  17. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases

    PubMed Central

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K. G.

    2016-01-01

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007) Proc Natl Acad Sci USA 104(22):9346−9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ∼85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45–90 d, starting with an initial formamide weight fraction of 10−3 wt % that is typical for concentrations in shallow lakes on early Earth. PMID:27044100

  18. Nutrient-contaminant (Pu) plant accumulation model

    SciTech Connect

    Cowan, C.E.; Jenne, E.A.; Simpson, J.C.; Cataldo, D.A.

    1981-12-01

    A model was developed which simulates the movement and daily accumulation of nutrients and contaminants in crop plants resulting from known physiological processes in the plant. In the model, the daily contaminant accumulation is governed by daily increase in plant biomass derived from photosynthesis and by the specified thermodynamic activity of the bioavailable contaminant species in soil or hydroponic solutin. Total accumulation and resulting concentration in the plant's root, stem and branch, leaf, and reproductive compartments can be simulated any time during the growing season. Parameters were estimated from data on plutonium accumulation in soybeans and the model was calibrated against this same data set. The plutonium distribution in the plant was found to be most sensitive to parameters related to leaf accumulation. Contamination at different times during the growing season resulted in a large change in predicted leaf accumulation but very little change in predicted accumulation in other plant parts except when contamination occurred very late in the growing season.

  19. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities.

    PubMed

    Gutiérrez-Gutiérrez, Silvia C; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart

    2015-08-01

    Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58±6mgkg(-1) for REEs comprising 44±8mgkg(-1) for light REEs, 11±2mgkg(-1) for heavy REEs and 3±1mgkg(-1) for Scandium (Sc) and 3±1.0mgkg(-1) of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are also recovered for reprocessing.

  20. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities.

    PubMed

    Gutiérrez-Gutiérrez, Silvia C; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart

    2015-08-01

    Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58±6mgkg(-1) for REEs comprising 44±8mgkg(-1) for light REEs, 11±2mgkg(-1) for heavy REEs and 3±1mgkg(-1) for Scandium (Sc) and 3±1.0mgkg(-1) of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are also recovered for reprocessing. PMID:25957938

  1. Instability of bottom-water redox conditions during accumulation of Quaternary sediment in the Japan Sea

    USGS Publications Warehouse

    Piper, D.Z.; Isaacs, C.M.

    1996-01-01

    The concentrations of Cd, Cr, Cu, Mo, Ni, Sb, U, V, and Zn were measured in early Quaternary sediment (1.32 to 1.08 Ma) from the Oki Ridge in the Japan Sea. The elements were partitioned between a detrital fraction, composed of terrigenous and volcaniclastic aluminosilicate debris, and a marine fraction, composed of biogenic and hydrogenous debris derived from seawater. The most important factors controlling minor-element accumulation rates in the marine fraction were (1) primary productivity in the photic zone, which largely controlled the flux of particulate organic-matter-bound minor elements settling through the water column and onto the seafloor, and (2) bottom-water redox, which determined the suite of elements that accumulated directly from seawater. This marine fraction of minor elements on Oki Ridge recorded six periods of high minor-element abundance. Assuming a constant bulk sediment accumulation rate, each period lasted roughly 5,000 to 10,000 years with a 41,000-year cycle. Accumulation rates of individual elements such as Cd, Mo, and U suggest sulfate-reducing conditions were established in the bottom water during the 10,000-year periods; accumulation rates of Cr and V during the intervening periods are indicative of less reducing, denitrifying conditions. Interelement ratios, for example, Cu:Mo, V:Cr, and Sb:Mo, further reflect bottom-water instability, such that bottom-water redox actually varied from sulfate reducing to denitrifying during the periods of highest minor-element accumulation rates; it varied from denitrifying to oxidizing during the intervening periods. Sediment lithology supports these interpretations of the minor-element distributions; the sediment is finely laminated for several of the periods represented by Cd, Mo, and U maxima and weakly laminated to bioturbated for the intervening periods. The geochemistry of this sediment demonstrates the unambiguous signal of Mo, principally, but of several other minor elements as well in

  2. Sequential biases in accumulating evidence

    PubMed Central

    Huggins, Richard; Dogo, Samson Henry

    2015-01-01

    Whilst it is common in clinical trials to use the results of tests at one phase to decide whether to continue to the next phase and to subsequently design the next phase, we show that this can lead to biased results in evidence synthesis. Two new kinds of bias associated with accumulating evidence, termed ‘sequential decision bias’ and ‘sequential design bias’, are identified. Both kinds of bias are the result of making decisions on the usefulness of a new study, or its design, based on the previous studies. Sequential decision bias is determined by the correlation between the value of the current estimated effect and the probability of conducting an additional study. Sequential design bias arises from using the estimated value instead of the clinically relevant value of an effect in sample size calculations. We considered both the fixed‐effect and the random‐effects models of meta‐analysis and demonstrated analytically and by simulations that in both settings the problems due to sequential biases are apparent. According to our simulations, the sequential biases increase with increased heterogeneity. Minimisation of sequential biases arises as a new and important research area necessary for successful evidence‐based approaches to the development of science. © 2015 The Authors. Research Synthesis Methods Published by John Wiley & Sons Ltd. PMID:26626562

  3. Natural radionuclide accumulation by raindrops

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. A time resolution of up to 1 minute allows a detailed comparison of changes in meteorological parameters with those of a concentration of ambient radon progenies in the atmosphere. Results of a study of variation of a fallout of radon progenies ^{214}Pb and ^{214}Bi concomitanting rainfalls are present. The radionuclide fallout rate is reconstructed from the observed gamma rate through a simulation of the first kind Volterra integral equation with difference kernel, determined by ratio of precipitating rates of 214Pb and 214Bi and their decay half times. An original straightforward step-by-step procedure was used for the numerical solution of the equation. The radionuclide concentration in the rainwater is calculated as a ratio of the reconstructed fallout to the measured rainfall. It was observed that the radionuclide fallout rate increases as the rainfall one in approximately power 0.6, i.e. the same as the mean raindrop volume. The concentration thereafter decreases as the rainfall rate in power 0.4. A numerical simulation of the process of accumulation of the radionuclides during diffusion and coalescence drop growth and aerosol scavenging during a passage from a cloud to the ground was performed. The results of the simulations agree with the experimental data.

  4. Accumulation of radium in relation to some chemical analogues in Dicranopteris linearis.

    PubMed

    Chao, J H; Chuang, C Y

    2011-01-01

    This study elucidates the uptake and accumulation of radium in the field-growing fern Dicranopteris linearis by relating the radium concentration to some potential chemical analogues, including alkaline earth metals, rare earth elements, and some important heavy metals. Time-dependent accumulation of radium and these chemical analogues for D. linearis were described by the (228)Th/(228)Ra activity ratio, an index for inferring plant age. The correlation between radium and these elements was assessed by statistical analysis and used as a reference to elucidate the uptake and accumulation of radium in relation to the chemical analogues. Analytical and statistical results showed that the concentrations of alkaline earth metals (except for Mg) rare earth elements and some heavy metals in D. linearis increased linearly with plant age. These elements, exhibiting a similar accumulation pattern to radium and significant correlation coefficients with radium, were considered as the chemical analogues to radium. Additionally, the plant/soil concentration ratios (CRs) for radium and most of these analogues in D. linearis exceeded 1, consistent with the definition of hyper-accumulator plants.

  5. Pb and Zn accumulation in a Cd-hyperaccumulator (Viola baoshanensis).

    PubMed

    Wu, Chuan; Liao, Bin; Wang, Sheng-Long; Zhang, Jun; Li, Jin-Tian

    2010-08-01

    Viola baoshanensis has been identified as a Cd-hyperaccumulator, however, its ability to accumulate Pb or Zn is less certain. Therefore, this study focused on determining whether or not V. baoshanensis can accumulate Pb or Zn, by means of field survey, hydroponic and pot experiments. In addition, we also tried to obtain further information on the Cd hyperaccumulating characteristics of this species. Under field conditions, V. baoshanensis accumulated on average 1090 mg Cd kg(-1), 1902 mg Pb kg(-1) and 3428 mg Zn kg(-1) in its shoots, respectively. In hydroponic and pot experiments, V. baoshanensis showed high tolerance to Cd, Pb, and Zn, as well as the ability to accumulate exceptionally high concentrations of the three elements in its shoots (> 2% Cd, > 1% Pb, and > 0.5% Zn on a dry matter basis). These results, taken together, suggested that V. baoshanensis is not only a Cd-hyperaccumulator, but also a strong accumulator of Pb and Zn.

  6. Scale-emergence of snowmelt runoff recession based on heterogeneous snow accumulation and melt

    NASA Astrophysics Data System (ADS)

    Luce, Charles; Tarboton, David; Clark, Martyn

    2016-04-01

    Snow drifts are usually seen as small elements in mountain landscapes; so are inconsistently considered in hydrologic modeling. Their small spatial representation in the landscape belies an outsize influence in the recession characteristics of mountain watersheds. Differential accumulation and melt of mountain snowpacks can shift center of spring runoff timing by months compared to expectations based on a uniform snowpack. Here we develop the quantification of melt and flow recession as an emergent characteristic from heterogeneity in snowpack accumulation and melt. While previous work has demonstrated the ties between differential accumulation and depletion of snowpacks, the importance of differential melt in concert with differential accumulation is less well explored. We develop a framework for showing the combined effects of joint spatial variability in accumulation and melt. Further, we relate the information to alternative methods for estimating snow depletion curves.

  7. Pb and Zn accumulation in a Cd-hyperaccumulator (Viola baoshanensis).

    PubMed

    Wu, Chuan; Liao, Bin; Wang, Sheng-Long; Zhang, Jun; Li, Jin-Tian

    2010-08-01

    Viola baoshanensis has been identified as a Cd-hyperaccumulator, however, its ability to accumulate Pb or Zn is less certain. Therefore, this study focused on determining whether or not V. baoshanensis can accumulate Pb or Zn, by means of field survey, hydroponic and pot experiments. In addition, we also tried to obtain further information on the Cd hyperaccumulating characteristics of this species. Under field conditions, V. baoshanensis accumulated on average 1090 mg Cd kg(-1), 1902 mg Pb kg(-1) and 3428 mg Zn kg(-1) in its shoots, respectively. In hydroponic and pot experiments, V. baoshanensis showed high tolerance to Cd, Pb, and Zn, as well as the ability to accumulate exceptionally high concentrations of the three elements in its shoots (> 2% Cd, > 1% Pb, and > 0.5% Zn on a dry matter basis). These results, taken together, suggested that V. baoshanensis is not only a Cd-hyperaccumulator, but also a strong accumulator of Pb and Zn. PMID:21166282

  8. Rolling-Element Bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Anderson, W. J.

    1983-01-01

    Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

  9. An experimental investigation of nonresonance photon accumulation in a system of spherical mirrors

    NASA Astrophysics Data System (ADS)

    Popov, S. S.; Atlukhanov, M. G.; Burdakov, A. V.; Ushkova, M. Yu.

    2016-07-01

    A new, nonresonant approach to photon accumulation in a system of two spherical mirrors is demonstrated experimentally. A high accumulation coefficient is obtained experimentally, and sufficient efficiency of this technique for application in such areas as spectroscopy, photochemistry, and photon neutralization of negative-ion beams is demonstrated. The photon accumulation efficiency is determined mainly by mirror reflectivity. It is nearly independent of the quality of the coupled-in radiation and does not require very high precision in aligning optical elements. The experimentally obtained data agree with theoretical calculations.

  10. Accumulation and hyperaccumulation of copper in plants

    NASA Astrophysics Data System (ADS)

    Adam, V.; Trnkova, L.; Huska, D.; Babula, P.; Kizek, R.

    2009-04-01

    Copper is natural component of our environment. Flow of copper(II) ions in the environment depends on solubility of compounds containing this metal. Mobile ion coming from soil and rocks due to volcanic activity, rains and others are then distributed to water. Bio-availability of copper is substantially lower than its concentration in the aquatic environment. Copper present in the water reacts with other compounds and creates a complex, not available for organisms. The availability of copper varies depending on the environment, but moving around within the range from 5 to 25 % of total copper. Thus copper is stored in the sediments and the rest is transported to the seas and oceans. It is common knowledge that copper is essential element for most living organisms. For this reason this element is actively accumulated in the tissues. The total quantity of copper in soil ranges from 2 to 250 mg / kg, the average concentration is 30 mg / kg. Certain activities related to agriculture (the use of fungicides), possibly with the metallurgical industry and mining, tend to increase the total quantity of copper in the soil. This amount of copper in the soil is a problem particularly for agricultural production of food. The lack of copper causes a decrease in revenue and reduction in quality of production. In Europe, shows the low level of copper in total 18 million hectares of farmland. To remedy this adverse situation is the increasing use of copper fertilizers in agricultural soils. It is known that copper compounds are used in plant protection against various illnesses and pests. Mining of minerals is for the development of human society a key economic activity. An important site where the copper is mined in the Slovakia is nearby Smolníka. Due to long time mining in his area (more than 700 years) there are places with extremely high concentrations of various metals including copper. Besides copper, there are also detected iron, zinc and arsenic. Various plant species

  11. Trace metal accumulation in carbonate biominerals of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Demina, L. L.; Oskina, N. S.; Galkin, S. V.

    2016-01-01

    New data on trace metal (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb) distribution in carbonate biominerals formed in geochemically different oceanic environments are discussed. Calcite shells of shelf and deepwater hydrothermal vent mussels as well as planktic foraminifers and pteropods from the central Atlantic Ocean have been studied. The variability in concentrations of most trace elements between different groups of calcifying organisms are usually within one order of magnitude, except for Fe and Mn, the elevated contents of which in microfossils are caused by post-sedimentation interaction. Different groups of calcifying organisms demonstrate a biogeochemical uniformity in trace metal accumulation during the biomineralization processes.

  12. Discrete Element Modeling

    SciTech Connect

    Morris, J; Johnson, S

    2007-12-03

    The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.

  13. Element by Element Abundances in Spheroidal Galaxies

    NASA Astrophysics Data System (ADS)

    Worthey, Guy; Serven, Jedidiah

    2006-02-01

    Element-by-element abundances will be derived from high quality long slit KPNO 4m spectra of nearby elliptical galaxies that span the range of velocity dispersion. Analysis of these spectra will give the abundances of 18 individual elements to bring to extragalactic astronomy the same luxurious situation now enjoyed only by stellar spectroscopists. These spectra will reveal the basic element ratio behavior as a function of galaxy velocity dispersion. For example, [Mg/Fe] is seen to be enhanced in large galaxies, but not small ones. We propose to expand our purview from 2 elements (Mg and Fe) to 18 elements. This, in turn, will tie directly to chemical evolution and chemical enrichment mechanisms. As a byproduct, we also decrease the stellar population age uncertainty by about a factor of ten from today's Balmer-metal index diagram techniques.

  14. Multiproxy (pollen, stable isotopes, trace elements) reconstruction of climate variability in northeastern Amazon during the late Holocene

    NASA Astrophysics Data System (ADS)

    Conte, M. H.; Urrego, D. H.; Charles-Dominique, P.; Giraudeau, J.; Martinez, P.; Bush, M. B.; Huang, Y.; Russell, J. M.; Gaucher, P.

    2013-12-01

    Model projections of future climate predict changes in ocean-atmosphere processes that will affect the organization of the Atlantic Intertropical Convergence Zone (ITCZ) and ENSO, and in turn, precipitation patterns over much of South America. The northeastern Amazon is particularly sensitive to ITCZ and ENSO organization, and experiences major episodes of drought and rainfall extremes due to interannual variability in ITCZ intensity and position. Hence understanding Holocene climate variability in the northeastern Amazon, and its phasing with other South American records, can provides new insights into past ITCZ organization and Atlantic-Pacific teleconnections. Lac Toponowini is a landslide-dammed lake in the undisturbed highland rainforest of French Guiana (Guyane). Toponowini sediments are finely varved, with pronounced light-dark couplets that appear to reflect alternating wet and dry season conditions. High-resolution X-Ray Fluorescence (XRF) profiling reveals that the couplets consist of bands of weathered clays and organic-rich material containing co-precipitated sulfides and platinum group elements (PGEs), sourced from gold deposits in the watershed. Mobility of PGEs is highly sensitive to hydrology and groundwater chemistry, and subtle variations in PGE flux and composition in Lac Toponowini appears to track past hydrologic conditions. Of note is the inverse correlation between the Pd/Pb ratio in Toponowini sediments and the %Ti record of fluvial input into the Cariaco Basin (Peterson and Haug 2006, Palaeogeog. Palaeoclim. Palaeoecol. 234, 97-113), which suggests antiphasing between rainfall in northern South America and French Guiana, consistent with ITCZ migration forced by multidecadal Atlantic variability. The carbon isotopic composition (δ13C) of terrestrial leaf waxes exhibits a maximum at ~1500 years BP, consistent with pollen evidence (Ledru 2001, Rev. Paleobot. Palynol. 115, 161-176) for ecosystem adaptations indicative of drier conditions in

  15. Elements of Film.

    ERIC Educational Resources Information Center

    Bobker, Lee R.

    A film is the successful combination of two distinct groups of elements: (1) the technical elements by which the film is made (camera, lighting, sound and editing) and (2) the esthetic elements that transform the craft into an art. This book attempts to combine the study of these elements by providing technical information about the process of…

  16. Organic Elemental Analysis.

    ERIC Educational Resources Information Center

    Ma, T. S.; Wang, C. Y.

    1984-01-01

    Presents a literature review on methods used to analyze organic elements. Topic areas include methods for: (1) analyzing carbon, hydrogen, and nitrogen; (2) analyzing oxygen, sulfur, and halogens; (3) analyzing other elements; (4) simultaneously determining several elements; and (5) determing trace elements. (JN)

  17. Characterization and source identification of trace elements in airborne particulates at urban and suburban atmospheres of Tabriz, Iran.

    PubMed

    Gholampour, Akbar; Nabizadeh, Ramin; Hassanvand, Mohammad Sadegh; Taghipour, Hasan; Rafee, Mohammad; Alizadeh, Zahra; Faridi, Sasan; Mahvi, Amir Hossein

    2016-01-01

    Concentration of particulate matter (PM10 and total suspended particulate (TSP)) and their elemental constituents were measured to identify the major sources of elements in urban and industrial suburban sites in Tabriz, Iran, from September 2012 to June 2013. TSP and PM10 samples were collected using high-volume samplers. Concentrations of 31 elements in aerosols and crustal soil were determined by ICPMS. The most abundant detected metals in the urban sampling sites were Al (217.5-4019.9 ng m(-3)), Fe (272.5-7658.0 ng m(-3)), Pt (4.7-1994.4 ng m(-3)), and P (13.6-2054.8 ng m(-3) (for TSP and Al (217.6-3687.3 ng m(-3)), Fe (197.1-3724.9 ng m(-3)), Pt (65.9-2054.5 ng m(-3)), and P (11.0-756.6 ng m(-3)( for PM10. In the suburban sampling site, the most abundant detected metals were Al (2083.0-9664.0 ng m(-3)), Fe (360.0-7221.5 ng m(-3)), P (229.4-870.5 ng m(-3)), and Ti (137.3-849.7 ng m(-3)) for TSP and Al (218.5-4179.6 ng m(-3)), Fe (106.3-2005.1 ng m(-3)), P (251.9-908.4 ng m(-3)), and Ba (10.6-584.9 ng m(-3)) for PM10. For the crustal soil, the most abundant detected elements included Al (60,088-60,694 ppm), Fe (19,886-20,474 ppm), Ti (894-3481 ppm), and Si (365-4246 ppm). Key emission sources were identified, and the concentrations contributed from individual sources were estimated. Enrichment factor (EF) explaining a preponderance of the variance in the data was applied to the datasets. EF calculations revealed that non-crustal trace elements were more enriched in the urban than suburban sampling sites. Results of the factor analysis on the elements showed that emissions from road traffic (involving oil and fuel combustions by vehicles, platinum group elements from vehicle exhaust, and resuspension of particulate matter from polluted soil) and construction dust from nearby construction sites and electricity generation plant were the major contributors of anthropogenic metals at ambient atmosphere in Tabriz. Results of this study elucidated the need for

  18. Characterization and source identification of trace elements in airborne particulates at urban and suburban atmospheres of Tabriz, Iran.

    PubMed

    Gholampour, Akbar; Nabizadeh, Ramin; Hassanvand, Mohammad Sadegh; Taghipour, Hasan; Rafee, Mohammad; Alizadeh, Zahra; Faridi, Sasan; Mahvi, Amir Hossein

    2016-01-01

    Concentration of particulate matter (PM10 and total suspended particulate (TSP)) and their elemental constituents were measured to identify the major sources of elements in urban and industrial suburban sites in Tabriz, Iran, from September 2012 to June 2013. TSP and PM10 samples were collected using high-volume samplers. Concentrations of 31 elements in aerosols and crustal soil were determined by ICPMS. The most abundant detected metals in the urban sampling sites were Al (217.5-4019.9 ng m(-3)), Fe (272.5-7658.0 ng m(-3)), Pt (4.7-1994.4 ng m(-3)), and P (13.6-2054.8 ng m(-3) (for TSP and Al (217.6-3687.3 ng m(-3)), Fe (197.1-3724.9 ng m(-3)), Pt (65.9-2054.5 ng m(-3)), and P (11.0-756.6 ng m(-3)( for PM10. In the suburban sampling site, the most abundant detected metals were Al (2083.0-9664.0 ng m(-3)), Fe (360.0-7221.5 ng m(-3)), P (229.4-870.5 ng m(-3)), and Ti (137.3-849.7 ng m(-3)) for TSP and Al (218.5-4179.6 ng m(-3)), Fe (106.3-2005.1 ng m(-3)), P (251.9-908.4 ng m(-3)), and Ba (10.6-584.9 ng m(-3)) for PM10. For the crustal soil, the most abundant detected elements included Al (60,088-60,694 ppm), Fe (19,886-20,474 ppm), Ti (894-3481 ppm), and Si (365-4246 ppm). Key emission sources were identified, and the concentrations contributed from individual sources were estimated. Enrichment factor (EF) explaining a preponderance of the variance in the data was applied to the datasets. EF calculations revealed that non-crustal trace elements were more enriched in the urban than suburban sampling sites. Results of the factor analysis on the elements showed that emissions from road traffic (involving oil and fuel combustions by vehicles, platinum group elements from vehicle exhaust, and resuspension of particulate matter from polluted soil) and construction dust from nearby construction sites and electricity generation plant were the major contributors of anthropogenic metals at ambient atmosphere in Tabriz. Results of this study elucidated the need for

  19. Molecular analysis of polyphosphate accumulation in bacteria.

    PubMed

    Kuroda, A; Ohtake, H

    2000-03-01

    The dynamic behavior of inorganic polyphosphate (polyP), its accumulation and disappearance, is the most striking aspect of polyP metabolism in bacteria. Imbalance between polyP synthesis and degradation results in fluctuations of polyP by 100- to 1000-fold. We here review recent results with respect to this polyP metabolism in bacteria. PolyP accumulation in response to amino acid starvation, accompanied by increased levels of stringent factors, has been observed in Escherichia coli. Inhibition by stringent factors of polyphosphatase interrupts the dynamic balance between the synthesis and degradation of polyP, accounting for polyP accumulation. Polyphosphate kinase is required for activation of intracellular protein degradation, which is required for adaptation at the onset of amino acid starvation. The adaptation to amino acid starvation is mediated by the network of stringent response and polyP metabolism. PolyP accumulation independent of stringent response has also been observed. Novobiocin, an inhibitor for DNA gyrase, stimulated accumulation of polyP but not that of stringent factors. However, a temperature-sensitive DNA gyrase mutant did not exhibit polyP accumulation at the non-permissive temperature. Antagonistic relationship of polyP to nucleic acid synthesis, explored by Harold, appears to be more complicated. We discuss relationship of Pi regulation to polyP accumulation in E. coli and Klebsiella aerogenes. A function of polyP as an in vivo phosphagen affecting polyP accumulation is also discussed.

  20. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired pressure vessel in which energy is stored under high pressure in the form of a gas or a gas and hydraulic... result in contamination of the hydraulic fluid and loss of gas through absorption. (c) Each...

  1. 46 CFR 58.30-25 - Accumulators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... RELATED SYSTEMS Fluid Power and Control Systems § 58.30-25 Accumulators. (a) An accumulator is an unfired pressure vessel in which energy is stored under high pressure in the form of a gas or a gas and hydraulic... result in contamination of the hydraulic fluid and loss of gas through absorption. (c) Each...

  2. Predatory aquatic beetles, suitable trace elements bioindicators.

    PubMed

    Burghelea, Carmen I; Zaharescu, Dragos G; Hooda, Peter S; Palanca-Soler, Antonio

    2011-05-01

    Predatory aquatic beetles are common colonizers of natural and managed aquatic environments. While as important components of the aquatic food webs they are prone to accumulate trace elements, they have been largely neglected from metal uptake studies. We aim to test the suitability of three dytiscid species, i.e.Hydroglyphus pusillus, Laccophilus minutus and Rhantus suturalis, as trace elements (Al, As, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Se and Zn) bioindicators. The work was carried out in a case area representing rice paddies and control sites (reservoirs) from an arid region known for its land degradation (Monegros, NE Spain). Categorical principal component analysis (CATPCA) was tested as a nonlinear approach to identify significant relationships between metals, species and habitat conditions so as to examine the ability of these species to reflect differences in metal uptake. Except Se and As, the average concentrations of all other elements in the beetles were higher in the rice fields than in the control habitats. The CATPCA determined that H. pusillus had high capacity to accumulate Fe, Ni and Mn regardless of the habitat type, and hence may not be capable of distinguishing habitat conditions with regards to these metals. On the other hand, L. minutus was found less sensitive for Se in non-managed habitats (i.e. reservoirs), while R. suturalis was good in accumulating Al, Mo and Pb in rice fields. The latter seems to be a promising bioindicator of metal enrichment in rice fields. We conclude that predatory aquatic beetles are good candidates for trace elements bioindication in impacted and non-impacted environments and can be used in environmental monitoring studies. CATPCA proved to be a reliable approach to unveil trends in metal accumulation in aquatic invertebrates according to their habitat status.

  3. [Job crisis and transformations in the new model of accumulation].

    PubMed

    Zerda-Sarmiento, Alvaro

    2012-06-01

    The general and structural crisis capitalism is going through is the token of the difficulties accumulation model has been dealing with since 70's in developed countries. This model has been trying to settle down again on the basis of neoliberal principle and a new technical-economical paradigm. The new accumulation pattern has had a effect in employment sphere which have been made evident at all the elements that constitute work relationships. In Colombia, this model implementation has been partial and segmented. However, its consequences (and the long-term current crisis) have been evident in unemployment, precarious work, segmentation, informal work and restricted and private health insurance. Besides, financial accumulation makes labour profits flow at different levels. The economic model current government has aimed to implement leads to strengthening exports, so making population life conditions more difficult. In order to overcome the current state of affairs, the work sphere needs to become more creative. This creative approach should look for new schemes for expression and mobilization of work sphere's claims. This is supposed to be done by establishing a different economic model aimed to build a more inclusive future, with social justice. PMID:23258748

  4. Electrochemical accumulation of visible gold on pyrite and arsenopyrite surfaces

    NASA Astrophysics Data System (ADS)

    Möller, P.; Kersten, G.

    1994-09-01

    In galvanic cell arrangements gold is electrochemically deposited on semiconducting sulfide minerals (pyrite, arsenopyrite, chalcopyrite) from aerated as well as H2S-saturated, gold-bearing 1 M KCl solutions. Observed cell potential differences of about 0.4 0.6 V in setups with one sulfide in aerated (cathode) and the other in H2S-saturated (anode) solutions are comparable with known “self-potentials” of natural sulfide ore bodies. Gold preferentially accumulates on the cathode, i.e. under oxidizing conditions. Linked sulfides of variable composition in the same environment, either oxidizing or reducing, yield potential differences up to 20 mV. Such assemblages simulate conditions typically occurring at surfaces of chemically inhomogeneous single crystals (e.g. zonation). Depending on chemical composition, sulfide minerals show either n- or p-type conductivity. Visible gold is preferentially accumulated on individual domains of sulfide surfaces that act as cathodes, i.e. p-type conductors in n-p junctions. The experimental results are discussed in view of electrochemical accumulation of visible gold on sulfides in nature. Arsenic is the most important element in establishing p-type conductivity of pyrite and arsenopyrite. This feature may explain why As is such a powerful pathfinder in gold exploration.

  5. [Job crisis and transformations in the new model of accumulation].

    PubMed

    Zerda-Sarmiento, Alvaro

    2012-06-01

    The general and structural crisis capitalism is going through is the token of the difficulties accumulation model has been dealing with since 70's in developed countries. This model has been trying to settle down again on the basis of neoliberal principle and a new technical-economical paradigm. The new accumulation pattern has had a effect in employment sphere which have been made evident at all the elements that constitute work relationships. In Colombia, this model implementation has been partial and segmented. However, its consequences (and the long-term current crisis) have been evident in unemployment, precarious work, segmentation, informal work and restricted and private health insurance. Besides, financial accumulation makes labour profits flow at different levels. The economic model current government has aimed to implement leads to strengthening exports, so making population life conditions more difficult. In order to overcome the current state of affairs, the work sphere needs to become more creative. This creative approach should look for new schemes for expression and mobilization of work sphere's claims. This is supposed to be done by establishing a different economic model aimed to build a more inclusive future, with social justice.

  6. Trace elements in feed, manure, and manured soils.

    PubMed

    Sheppard, S C; Sanipelli, B

    2012-01-01

    Modern animal feeds often include nutritional mineral supplements, especially elements such as Cu, P, Se, and Zn. Other sources of trace elements also occur in livestock systems, such as pharmaceutical use of As and Zn to control gut flora, Bi in dairy for mastitis control, and Cu as hoof dips. Additionally, potential exists for inadvertent inclusion of trace elements in feeds or manures. There is concern about long-term accumulation of trace elements in manured soil that may even exceed guideline "safe" concentrations. This project measured ∼60 elements in 124 manure samples from broiler, layer, turkey, swine grower, swine nursery, sow, dairy, and beef operations. The corresponding feeds were also analyzed. In general, concentrations in manure were two- to fivefold higher than those in feed: the manure/feed concentration ratios were relatively consistent for all the animal-essential elements and were numerically similar for many of the non-nutrient elements. To confirm the potential for accumulation in soil, total trace element concentrations were measured in the profiles of 10 manured and 10 adjacent unmanured soils. Concentrations of several elements were found to be elevated in the manured soils, with Zn (and P) the most common. One soil from a dairy standing yard had concentrations of B that exceeded soil health guideline concentrations. Given that the Cu/P and Zn/P ratios found in manure were greater than typically reported in harvested crop materials, these elements will accumulate in soil even if manure application rates are managed to prevent accumulation of P in soil.

  7. Abundances of Ag and Cu in mantle peridotites and the implications for the behavior of chalcophile elements in the mantle

    NASA Astrophysics Data System (ADS)

    Wang, Zaicong; Becker, Harry

    2015-07-01

    Silver abundances in mantle peridotites and the behavior of Ag during high temperature mantle processes have received little attention and, as a consequence, the abundance of Ag in the bulk silicate Earth (BSE) has been poorly constrained. In order to better understand the processes that fractionate Ag and other chalcophile elements in the mantle, abundances of Ag and Cu in mantle peridotites from different geological settings (n = 68) have been obtained by isotope dilution ICP-MS methods. In peridotite tectonites and in a few suites of peridotite xenoliths which display evidence for variable extents of melt depletion and refertilization by silicate melts, Ag and Cu abundances show positive correlations with moderately incompatible elements such as S, Se, Te and Au. The mean Cu/Ag in fertile peridotites (3500 ± 1200, 1s, n = 38) is indistinguishable from the mean Cu/Ag of mid ocean ridge basalts (MORB, 3600 ± 400, 1s, n = 338) and MORB sulfide droplets. The constant mean Cu/Ag ratios indicate similar behavior of Ag and Cu during partial melting of the mantle, refertilization and magmatic fractionation, and thus should be representative of the Earth's upper mantle. The systematic fractionation of Cu, Ag, Au, S, Se and Te in peridotites and basalts is consistent with sulfide melt-silicate melt partitioning with apparent partition coefficients of platinum group elements (PGE) > Au ⩾ Te > Cu ≈ Ag > Se ⩾ S. Because of the effects of secondary processes, the abundances of chalcophile elements, notably S, Se, but also Cu and the PGE in many peridotite xenoliths are variable and lower than in peridotite massifs. Refertilization of peridotite may change abundances of chalcophile and lithophile elements in peridotite massifs, however, this seems to mostly occur in a systematic way. Correlations with lithophile and chalcophile elements and the overlapping mean Cu/Ag ratios of peridotites and ocean ridge basalts are used to constrain abundances of Ag and Cu in the BSE

  8. Accumulating Knowledge on Elementary Science Specialists: A Strategy for Building Conceptual Clarity and Sharing Findings

    ERIC Educational Resources Information Center

    Century, Jeanne; Rudnick, Mollie; Freeman, Cassie

    2008-01-01

    This article offers a framework for supporting identifying and organizing the elements that comprise elementary science specialist models. With these first building blocks, it is the hope of the author to create a foundation for shared language, conceptual understanding and accumulating knowledge about how to bring high quality science education…

  9. GESTATIONAL MERCURY VAPOR EXPOSURE AND DIET CONTRIBUTE TO MERCURY ACCUMULATION IN NEONATAL RATS.

    EPA Science Inventory

    Exposure of pregnant Long-Evans rats to elemental mercury (Hg0) vapor resulted in a significant

    accumulation of Hg in tissues of neonates. Because elevated Hg in neonatal tissues may adversely

    affect growth and development, we were interested in how rapidly Hg was...

  10. Gene limiting cadmium accumulation in rice.

    PubMed

    Ueno, Daisei; Yamaji, Naoki; Kono, Izumi; Huang, Chao Feng; Ando, Tsuyu; Yano, Masahiro; Ma, Jian Feng

    2010-09-21

    Intake of toxic cadmium (Cd) from rice caused Itai-itai disease in the past and it is still a threat for human health. Therefore, control of the accumulation of Cd from soil is an important food-safety issue, but the molecular mechanism for the control is unknown. Herein, we report a gene (OsHMA3) responsible for low Cd accumulation in rice that was isolated from a mapping population derived from a cross between a high and low Cd-accumulating cultivar. The gene encodes a transporter belonging to the P(1B)-type ATPase family, but shares low similarity with other members. Heterologous expression in yeast showed that the transporter from the low-Cd cultivar is functional, but the transporter from the high-Cd cultivar had lost its function, probably because of the single amino acid mutation. The transporter is mainly expressed in the tonoplast of root cells at a similar level in both the low and high Cd-accumulating cultivars. Overexpression of the functional gene from the low Cd-accumulating cultivar selectively decreased accumulation of Cd, but not other micronutrients in the grain. Our results indicated that OsHMA3 from the low Cd-accumulating cultivar limits translocation of Cd from the roots to the above-ground tissues by selectively sequestrating Cd into the root vacuoles.

  11. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases

    NASA Astrophysics Data System (ADS)

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K. G.

    2016-04-01

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007) Proc Natl Acad Sci USA 104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ˜85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of 10-310-3 wt % that is typical for concentrations in shallow lakes on early Earth.

  12. Accumulation of atmospheric sulfur in some Costa Rican soils

    USGS Publications Warehouse

    Bern, Carleton R.; Townsend, Alan R.

    2013-01-01

    Sulfur is one of the macronutrient elements whose sources to terrestrial ecosystems should shift from dominance by rock-weathering to atmospheric deposition as soils and underlying substrate undergo progressive weathering and leaching. However, the nature and timing of this transition is not well known. We investigated sources of sulfur to tropical rain forests growing on basalt-derived soils in the Osa Peninsula region of Costa Rica. Sulfur sources were examined using stable isotope ratios (δ34S) and compared to chemical indices of soil development. The most weathered soils, and the forests they supported, are dominated by atmospheric sulfur, while a less weathered soil type contains both rock-derived and atmospheric sulfur. Patterns of increasing δ34S with increasing soil sulfur concentration across the landscape suggest atmospheric sulfur is accumulating, and little rock-derived sulfur has been retained. Soil sulfur, minus adsorbed sulfate, is correlated with carbon and nitrogen, implying that sulfur accumulation occurs as plants and microbes incorporate sulfur into organic matter. Only the lower depth increments of the more weathered soils contained significant adsorbed sulfate. The evidence suggests a pattern of soil development in which sulfur-bearing minerals in rock, such as sulfides, weather early relative to other minerals, and the released sulfate is leached away. Sulfur added via atmospheric deposition is retained as organic matter accumulates in the soil profile. Adsorbed sulfate accumulates later, driven by changes in soil chemistry and mineralogy. These aspects of sulfur behavior during pedogenesis in this environment may hasten the transition to dominance by atmospheric sources.

  13. Accumulation of atmospheric sulfur in some Costa Rican soils

    NASA Astrophysics Data System (ADS)

    Bern, Carleton R.; Townsend, Alan R.

    2008-09-01

    Sulfur is one of the macronutrient elements whose sources to terrestrial ecosystems should shift from dominance by rock-weathering to atmospheric deposition as soils and underlying substrate undergo progressive weathering and leaching. However, the nature and timing of this transition is not well known. We investigated sources of sulfur to tropical rain forests growing on basalt-derived soils in the Osa Peninsula region of Costa Rica. Sulfur sources were examined using stable isotope ratios (δ34S) and compared to chemical indices of soil development. The most weathered soils, and the forests they supported, are dominated by atmospheric sulfur, while a less weathered soil type contains both rock-derived and atmospheric sulfur. Patterns of increasing δ34S with increasing soil sulfur concentration across the landscape suggest atmospheric sulfur is accumulating, and little rock-derived sulfur has been retained. Soil sulfur, minus adsorbed sulfate, is correlated with carbon and nitrogen, implying that sulfur accumulation occurs as plants and microbes incorporate sulfur into organic matter. Only the lower depth increments of the more weathered soils contained significant adsorbed sulfate. The evidence suggests a pattern of soil development in which sulfur-bearing minerals in rock, such as sulfides, weather early relative to other minerals, and the released sulfate is leached away. Sulfur added via atmospheric deposition is retained as organic matter accumulates in the soil profile. Adsorbed sulfate accumulates later, driven by changes in soil chemistry and mineralogy. These aspects of sulfur behavior during pedogenesis in this environment may hasten the transition to dominance by atmospheric sources.

  14. Effects of rare earth elements on the distribution of mineral elements and heavy metals in horseradish.

    PubMed

    Wang, Lihong; Huang, Xiaohua; Zhou, Qing

    2008-09-01

    In order to investigate the effects of rare earth elements (REEs) on horseradish, the distribution of the mineral elements and heavy metals in different organs of horseradish have been studied by using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Meanwhile, three variable major parameters, namely the concentration of REEs, the type of REEs, and the growth stage of plant were chosen. The results indicated that the test REEs, Ce(III) and Tb(III), could be accumulated in leaves, stems and roots of horseradish. In addition, we found that the content of mineral elements was increased in horseradish treated with 20mgl(-1) of Ce(III), but not those with the 20mgl(-1) of Tb(III). Moreover, the content of mineral elements in horseradish was decreased with the increasing concentration of REEs (100, 300mgl(-1)). Furthermore, we found that there were the opposite effects on the content of the heavy metals in horseradish treated with REEs. Finally, we found that the effect of REEs on the accumulation of REEs, and the content of mineral elements or heavy metals of horseradish during vigorous growth stage, no matter positive or negative, was more obvious than that of the other growth stages. These results demonstrated that the distribution behaviors of mineral elements and heavy metals in horseradish can be affected by the type and concentration of REEs, and the growth period of plant.

  15. Microbial accumulation of uranium, radium, and cesium

    SciTech Connect

    Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; North, S.E.

    1981-05-01

    Diverse microbial species varied considerably in their ability to accumulate uranium, cesium, and radium. Mechanistic differences in uranium uptake by Saccharomyces cerevisiae and Pseudomonas aeruginosa were indicated. S. serevisiae exhibited a slow (hours) surface accumulation of uranium which was subject to environmental factors, while P. aeruginosa accumulated uranium rapidly (minutes) as dense intracellular deposits and did not appear to be affected by environmental parameters. Metabolism was not required for uranium uptake by either organism. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several species tested.

  16. Element-ary Development.

    ERIC Educational Resources Information Center

    Schamp, Homer W., Jr.

    1989-01-01

    Describes the historic development of the periodic table from the four-element theory to the Lavoisier's table. Presents a table listing the old and new names of chemicals and the Lavoisier's table of elements. Lists two references. (YP)

  17. Trace Elements and Health

    ERIC Educational Resources Information Center

    Pettyjohn, Wayne A.

    1972-01-01

    Summarizes the effects of arsenic, lead, zinc, mercury, and cadmium on human health, indicates the sources of the elements in water, and considers the possibility of students in high schools analyzing water for trace amounts of the elements. (AL)

  18. Orthotropic hole element

    NASA Technical Reports Server (NTRS)

    Markham, J. W.; Smith, C. V.

    1983-01-01

    A finite element was developed to adequately represent the state of stress in the region around a circular hole in orthotropic material experiencing reasonably general loading. This has been achieved through a complementary virtual work formulation of the stiffness and stress matrices for a square element with a center circular hole. The element has been incorporated into COSMIC/NASTRAN as a dummy element. Sample problems have been solved and these results are presented.

  19. Elemental Chemical Puzzlers

    ERIC Educational Resources Information Center

    Thomas, Nicholas C.

    2009-01-01

    This paper provides nine short chemically based puzzles or problems extensible for use with students from middle school to college. Some of these will strengthen students' recognition of individual elements and element names. Others require students to focus on the salient properties of given chemical elements.

  20. Organic Elemental Analysis.

    ERIC Educational Resources Information Center

    Ma, T. S.; Gutterson, Milton

    1980-01-01

    Reviews general developments in computerization and data processing of organic elemental analyses; carbon, hydrogen, and nitrogen analyzers; procedures for determining oxygen, sulfur, and halogens, as well as other nometallic elements and organometallics. Selected papers on trace analysis of nonmetals and determination of metallic elements are…

  1. Waste tank ventilation system waste material accumulations

    SciTech Connect

    Van Vleet, R.J., Westinghouse Hanford

    1996-08-06

    This paper calculates the amount of material that accumulates in the ventilation systems of various Tank Waste Remediation System facilities and estimates the amount of material that could be released due to a rapid pressurization.

  2. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  3. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  4. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  5. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  6. 19 CFR 10.534 - Accumulation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.534 Accumulation. (a) Originating materials of Singapore or the United States...

  7. Accumulation of nickel in transgenic tobacco

    NASA Astrophysics Data System (ADS)

    Sidik, Nik Marzuki; Othman, Noor Farhan

    2013-11-01

    The accumulation of heavy metal Ni in the roots and leaves of four T1 transgenic lines of tobacco (T(1)20E, T(1)24C, T(1)18B1 and T(1)20B) expressing eiMT1 from E.indica was assessed. The aim of the study was to investigate the level of Ni accumulation in the leaves and roots of each transgenic lines and to evaluate the eligibility of the plants to be classified as a phytoremediation agent. All of the transgenic lines showed different ability in accumulating different metals and has translocation factor (TF) less than 1 (TF<1) at all levels of metal treatment. Among the 4 transgenic lines, transgenic line T(1)24C showed the highest accumulation of Ni (251.9 ± 0.014 mg/kg) and the lowest TF value (TFT(1)24C=0.0875) at 60 ppm Ni.

  8. 47 CFR 32.3100 - Accumulated depreciation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....3100 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM... investment contained in Account 2001, Telecommunications Plant in Service. (b) This account shall be credited... plant in service. (Note also Account 3300, Accumulated depreciation—nonoperating.) (c) At the time...

  9. 47 CFR 32.3100 - Accumulated depreciation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ....3100 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM... investment contained in Account 2001, Telecommunications Plant in Service. (b) This account shall be credited... plant in service. (Note also Account 3300, Accumulated depreciation—nonoperating.) (c) At the time...

  10. 47 CFR 32.3100 - Accumulated depreciation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ....3100 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM... investment contained in Account 2001, Telecommunications Plant in Service. (b) This account shall be credited... plant in service. (Note also Account 3300, Accumulated depreciation—nonoperating.) (c) At the time...

  11. Metal accumulation by wood-decaying fungi

    SciTech Connect

    Tyler, G.

    1982-01-01

    Metal concentrations (Na, K, Rb, Mg, Ca, Sr, Mn, Fe, Cu, Zn, Cd, Al, and Pb) in the sporophores of ten wood-decaying macromycete species were related to concentrations in the wood substrates. Manganese, Sr, Ca, and Pb were usually excluded by the fungi; K, Rb, and to a lower degree, Cd, Fe, Zn, Cu, Mg and Na were accumulated. Accumulation ratios are compared with similar ratios for soil and litter inhabiting species previously studied.

  12. Sucrose induces vesicle accumulation and autophagy.

    PubMed

    Higuchi, Takahiro; Nishikawa, Jun; Inoue, Hiroko

    2015-04-01

    It has been shown that the treatment of mammalian cells with sucrose leads to vacuole accumulation associated with lysosomes and upregulation of lysosomal enzyme expression and activity. Autophagy is an evolutionarily conserved homeostatic process by which cells deliver cytoplasmic material for degradation into lysosomes, thus it is probable that sucrose affects the autophagic activity. The role of sucrose in autophagy is unknown; however, another disaccharide, trehalose has been shown to induce autophagy. In the current study, we used mouse embryonic fibroblasts to investigate whether sucrose induces autophagy and whether vesicle formation is associated with autophagy. The results showed that sucrose induces autophagy while being accumulated within the endosomes/lysosomes. These vesicles were swollen and packed within the cytoplasm. Furthermore, trehalose and the trisaccharide raffinose, which are not hydrolyzed in mammalian cells, increased the rate of vesicles accumulation and LC3-II level (a protein marker of autophagy). However, fructose and maltose did not show the same effects. The correlation between the two processes, vesicle accumulation and autophagy induction, was confirmed by treatment of cells with sucrose plus invertase, or maltose plus acarbose-the α-glucosidase inhibitor-and by sucrose deprivation. Results also showed that vesicle accumulation was not affected by autophagy inhibition. Therefore, the data suggest that sucrose-induced autophagy through accumulation of sucrose-containing vesicles is caused by the absence of hydrolysis enzymes.

  13. Sodium accumulation in Atriplex. Final report

    SciTech Connect

    Norton, J.A.; Caldwell, M.M.; Richardson, S.G.

    1984-09-01

    This study was undertaken to determine the ecological significance and the significance to arid land reclamation of sodium accumulation and nonaccumulation in Atriplex. There was a continuum in the genetic tendency of Atriplex canescens to accumulate sodium, from populations which accumulated almost no sodium to populations which accumulated up to 7% in the leaves. There were also substantial differences in sodium uptake between populations of A. tridentata, A. falcata and A. gardneri, with some populations having less than 0.1% leaf sodium and other populations having up to 5 or 6%. In three experiments (a field study, a greenhouse pot study and a hydroponics study) there were no significant differences in salinity tolerance between sodium accumulating and nonaccumulating A. canescens: both genotypes were highly salt tolerant. There was a significant buildup of sodium in the soil beneath sodium accumulating Atriplex plants, both in natural populations and on revegetated oil shale study plots. The sodium buildup was not sufficient to be detrimental to the growth or establishment of most herbaceous species, but with older Atriplex plants or with more saline soil, the buildup could potentially be detrimental. 14 references, 42 figures, 3 tables.

  14. Sucrose induces vesicle accumulation and autophagy.

    PubMed

    Higuchi, Takahiro; Nishikawa, Jun; Inoue, Hiroko

    2015-04-01

    It has been shown that the treatment of mammalian cells with sucrose leads to vacuole accumulation associated with lysosomes and upregulation of lysosomal enzyme expression and activity. Autophagy is an evolutionarily conserved homeostatic process by which cells deliver cytoplasmic material for degradation into lysosomes, thus it is probable that sucrose affects the autophagic activity. The role of sucrose in autophagy is unknown; however, another disaccharide, trehalose has been shown to induce autophagy. In the current study, we used mouse embryonic fibroblasts to investigate whether sucrose induces autophagy and whether vesicle formation is associated with autophagy. The results showed that sucrose induces autophagy while being accumulated within the endosomes/lysosomes. These vesicles were swollen and packed within the cytoplasm. Furthermore, trehalose and the trisaccharide raffinose, which are not hydrolyzed in mammalian cells, increased the rate of vesicles accumulation and LC3-II level (a protein marker of autophagy). However, fructose and maltose did not show the same effects. The correlation between the two processes, vesicle accumulation and autophagy induction, was confirmed by treatment of cells with sucrose plus invertase, or maltose plus acarbose-the α-glucosidase inhibitor-and by sucrose deprivation. Results also showed that vesicle accumulation was not affected by autophagy inhibition. Therefore, the data suggest that sucrose-induced autophagy through accumulation of sucrose-containing vesicles is caused by the absence of hydrolysis enzymes. PMID:25389129

  15. 187Re-187Os systematics, highly siderophile element, S-Se-Te abundances in the components of unequilibrated L chondrites

    NASA Astrophysics Data System (ADS)

    Kadlag, Yogita; Becker, Harry

    2016-01-01

    The 187Re-187Os systematics, abundances of highly siderophile elements (HSE: Re, platinum group elements and Au), Te, Se and S as well as major and minor elements were determined in separated components of two unequilibrated L chondrites QUE 97008 (L3.05) and Ceniceros (L3.7). The 187Re-187Os systematics are disturbed in the components of both meteorites, most likely due to open system behavior of Re during terrestrial weathering of QUE 97008 and alteration on the L chondrite parent body as indicated by an internal errorchron generated for components of Ceniceros. The HSE abundance patterns suggest that the bulk rock abundances were mainly controlled by two different end members. Non-magnetic fractions display lower Re/Os and HSE/Ir than CI chondrites. Chondrules, metal-troilite spherules and fine magnetic fractions, are depleted in refractory HSE and show higher Rh/Ir, Pd/Ir and Au/Ir than in CI chondrites. The different HSE compositions indicate the presence of unequilibrated alloys and loss of refractory HSE-rich carrier phases from the precursors of some L chondrite components. Gold is decoupled from other HSE in magnetic fractions and shows chalcophile affinities with a grain size dependent variation similar to S and Se, presumably inherited from preaccretionary processes. Tellurium is depleted in all components compared to other analysed siderophile elements, and its abundance was most likely controlled by fractional condensation and different geochemical affinities. The volatility dependent depletion of Te requires different physical and chemical conditions than typical for the canonical condensation sequence as represented by carbonaceous chondrites. Tellurium also shows variable geochemical behavior, siderophile in Ceniceros, predominantly chalcophile in QUE 97008. These differences may have been inherited from element partitioning during chondrule formation. Selenium and S on the other hand are almost unfractionated from each other and only show

  16. Using chalcophile elements to constrain crustal contamination and xenolith-magma interaction in Cenozoic basalts of eastern China

    NASA Astrophysics Data System (ADS)

    Zeng, Gang; Huang, Xiao-Wen; Zhou, Mei-Fu; Chen, Li-Hui; Xu, Xi-Sheng

    2016-08-01

    Continental basalts have complicated petrogenetic processes, and their chemical compositions can be affected by multi-staged geological evolution. Compared to lithophile elements, chalcophile elements including Ni, platinum-group elements (PGEs) and Cu are sensitive to sulfide segregation and fractional crystallization during the evolution of mantle-derived magmas and can provide constraints on the genesis of continental basalts. Cenozoic intra-continental alkaline basalts in the Nanjing basaltic field, eastern China, include high-Ca and low-Ca varieties. All these basalts have poor PGE contents with Ir ranging from 0.016 ppb to 0.288 ppb and high Cu/Pd ratios from 0.7 × 105 to 4.7 × 105 (5.7 × 103 for DMM), indicating that they were derived from sulfide-saturated mantle sources with variable amounts of residual sulfide during melting or might undergo an early-sulfide segregation in the mantle. Relatively high Cu/Pd ratios along with high Pd concentrations for the high-Ca alkaline basalts indicate an additional removal of sulfide during magma ascent. Because these basalts have high, variable Pd/Ir ratios (2.8-16.8) with low Ce/Pb (9.9-19.7) ratios and εNd values (+ 3.6-+6.4), crustal contamination is proposed to be a potential process to induce the sulfide saturation and removal. Significantly increased Pd/Ir ratios for few high-Ca basalts can be explained by the fractionation of laurite or Ru-Os-Ir alloys with olivine or chromite. For low-Ca alkaline basalts, their PGE contents are well correlated with the MgO, Sc contents, incompatible element ratios (Lu/Hf, Na/Ti and Ca/Al) and Hf isotopes. Good correlations are also observed between Pd/Ir (or Rh/Ir) and Na/Ti (or Ca/Al) ratios. Variations of these elemental ratios and Hf isotopes is previously documented to be induced by the mixing of peridotite xenolith-released melts during ascent. Therefore, we suggest that such xenolith-magma interaction are also responsible for the variable PGE compositions of low

  17. Probing Interaction Between Platinum Group Metal (PGM) and Non-PGM Support Through Surface Characterization and Device Performance

    NASA Astrophysics Data System (ADS)

    Saha, Shibely

    High cost and limited abundance of Platinum (Pt) have hindered effective commercialization of Proton Exchange Membrane Fuel Cell and Electrolyzer. Efforts have been undertaken to reduce precious group metal (PGM) requirement for these devices without compromising the activity of the catalyst by using transition metal carbides (TMC) as non-PGM support thanks to their similar electronic and geometric structures as Pt. In this work Mo2C was selected as non-PGM support and Pt was used as the PGM of interest. We hypothesize that the hollow nanotube morphology of Mo2C support combined with Pt nano particles deposited on it via atomic layer deposition (ALD) technique would allow increased interaction between them which may increase the activity of Pt and Mo2C as well as maximize the Pt active surface area. Specifically, a rotary ALD equipment was used to grow Pt particles from atomic level to 2--3 nanometers by simply adjusting number of ALD cycles in order to probe the interaction between the deposited Pt nanoparticles and Mo2C nanotube support. Interaction between the Pt and Mo2 C was analyzed via surface characterization and electrochemical characterization. Interaction between Pt and Mo2C arises due to the lattice mismatch between Pt and Mo2C as well as electron migration between them. Lattice spacing analysis using high resolution transmission electron microscopy (HRTEM) images, combined with Pt binding energy shift in XPS results, clearly showed strong bonding between Pt nanoparticles and the Mo2C nanotube support in all the resultant Pt/Mo2C samples. We postulate that this strong interaction is responsible for the significantly enhanced durability observed in our constant potential electrolysis (CPE) and accelerated degradation testing (ADT). Of the three samples from different ALD cycles (15, 50 and 100), Mo2C nanotubes modified by 50 (1.07 wt% Pt loading) and 100 cycles (4.4 wt% Pt) of Pt deposition, showed higher HER and HOR activity per Pt mass than commercial 20% Pt supported on carbon black. Finally, we report the systematic investigation of the feasibility of this nanoscale Pt/Mo 2C catalyst in a practical device setting. The ORR activity of 100 Pt/Mo 2C was determined using the catalyst in the cathode of the MEA. Performance of this catalyst led the Pt utilization to be 10.35kWgPt-1 outperforming the target set by DOE for 2017--2020 by 30%.

  18. Numerical Results of 3-D Modeling of Moon Accumulation

    NASA Astrophysics Data System (ADS)

    Khachay, Yurie; Anfilogov, Vsevolod; Antipin, Alexandr

    2014-05-01

    For the last time for the model of the Moon usually had been used the model of mega impact in which the forming of the Earth and its sputnik had been the consequence of the Earth's collision with the body of Mercurial mass. But all dynamical models of the Earth's accumulation and the estimations after the Pb-Pb system, lead to the conclusion that the duration of the planet accumulation was about 1 milliard years. But isotopic results after the W-Hf system testify about a very early (5-10) million years, dividing of the geochemical reservoirs of the core and mantle. In [1,2] it is shown, that the account of energy dissipating by the decay of short living radioactive elements and first of all Al26,it is sufficient for heating even small bodies with dimensions about (50-100) km up to the iron melting temperature and can be realized a principal new differentiation mechanism. The inner parts of the melted preplanets can join and they are mainly of iron content, but the cold silicate fragments return to the supply zone and additionally change the content of Moon forming to silicates. Only after the increasing of the gravitational radius of the Earth, the growing area of the future Earth's core can save also the silicate envelope fragments [3]. For understanding the further system Earth-Moon evolution it is significant to trace the origin and evolution of heterogeneities, which occur on its accumulation stage.In that paper we are modeling the changing of temperature,pressure,velocity of matter flowing in a block of 3d spherical body with a growing radius. The boundary problem is solved by the finite-difference method for the system of equations, which include equations which describe the process of accumulation, the Safronov equation, the equation of impulse balance, equation Navier-Stocks, equation for above litho static pressure and heat conductivity in velocity-pressure variables using the Businesque approach.The numerical algorithm of the problem solution in velocity

  19. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities

    SciTech Connect

    Gutiérrez-Gutiérrez, Silvia C.; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart

    2015-08-15

    Highlights: • Samples from multiple core drills were obtained from 4× landfill sites in the UK. • Each sample analysed for rare earth elements, critical metals and valuable metals. • Two stage microwave digestion method ensuring high yield. • High quantities of copper and aluminium were observed in the soil layers of landfill. • Across 4× landfills aluminium and copper present has a value of around $400 million. - Abstract: Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58 ± 6 mg kg{sup −1} for REEs comprising 44 ± 8 mg kg{sup −1} for light REEs, 11 ± 2 mg kg{sup −1} for heavy REEs and 3 ± 1 mg kg{sup −1} for Scandium (Sc) and 3 ± 1.0 mg kg{sup −1} of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are

  20. Controls on Highly Siderophile Element Concentrations in Martian Basalt: Sulfide Saturation and Under-Saturation

    NASA Technical Reports Server (NTRS)

    Righter, Kevin

    2009-01-01

    Highly siderophile elements (HSE; Re, Au and the platinum group elements) in shergottites exhibit a wide range from very high, similar to the terrestrial mantle, to very low, similar to sulfide saturated mid ocean ridge basalt (e.g., [1]). This large range has been difficult to explain without good constraints on sulfide saturation or under-saturation [2]. A new model for prediction of sulfide saturation places new constraints on this problem [3]. Shergottite data: For primitive shergottites, pressure and temperature estimates are between 1.2-1.5 GPa, and 1350-1470 C [4]. The range of oxygen fugacities is from FMQ-2 to IW, where the amount of Fe2O3 is low and thus does not have a significant effect on the S saturation values. Finally, the bulk compositions of shergottites have been reported in many recent studies (e.g., [5]). All of this information will be used to test whether shergottites are sulfide saturated [3]. Modeling values and results: The database for HSE partition coefficients has been growing with many new data for silicates and oxides [6-8] to complement a large sulfide database [9- 11]. Combining these data with simple batch melting models allows HSE contents of mantle melts to be estimated for sulfide-bearing vs. sulfide-free mantle. Combining such models with fractional crystallization modeling (e.g., [12]) allows HSE contents of more evolved liquids to be modeled. Most primitive shergottites have high HSE contents (and low S contents) that can be explained by sulfide under-saturated melting of the mantle. An exception is Dhofar 019 which has high S contents and very low HSE contents suggesting sulfide saturation. Most evolved basaltic shergottites have lower S contents than saturation, and intermediate HSE contents that can be explained by olivine, pyroxene, and chromite fractionation. An exception is EET A79001 lithology B, which has very low HSE contents and S contents higher than sulfide saturation values . evidence for sulfide saturation

  1. Platinum and associated elements at the New Rambler mine and vicinity, Albany and Carbon Counties, Wyoming

    USGS Publications Warehouse

    Theobald, P.K.; Thompson, Charles Emmet

    1968-01-01

    Platinum-group metals in the Medicine Bow Mountains were first identified by W. C. Knight in 1901. In the Medicine Bow Mountains, these metals are commonly associated with copper, silver, or gold in shear zones that cut a series of mafic igneous and metamorphic rocks. At the New Rambler mine, where the initial discovery was made, about 50,000 tons of mine and mill waste contain an average of 0.3 percent copper, 7 ppm (parts per million) silver, 1 ppm platinum plus palladium, and 0.7 ppm gold. This material is believed to be from a low-grade envelope around the high-grade pod of complex ore that was mined selectively in the old workings. Soil samples in the vicinity of the New Rambler mine exhibit a wide range of content of several elements associated with the ore. Most of the variation can be attributed to contamination, from the mine workings. Even though soil samples identify a low-level copper anomaly that persists to the limit of the area sampled, soils do not offer a promising medium for tracing mineralization owing to the blanket of transported overburden. Stream sediments, if preconcentrated for analysis, do reveal anomalies not only in the contaminated stream below the New Rambler mine, but in adjacent drainage and on Dave Creek. Examination of a spectrum of elements in heavy-mineral concentrates from stream sediment may contribute to knowledge of the nature of the mineralization and of the basic geology of the environment. The sampling of bedrock exposures is not particularly fruitful because outcrops are sparse and the exposed rocks are the least altered and mineralized. Bedrock sampling does, however, provide information on the large size and provincial nature of the platinum-rich area. We feel that a properly integrated program of geological, geophysical, and geochemical exploration in the Medicine Bow Mountains and probably in the Sierra Madre to the west has a reasonable probability of successfully locating a complex ore body.

  2. Numerical Results of Earth's Core Accumulation 3-D Modelling

    NASA Astrophysics Data System (ADS)

    Khachay, Yurie; Anfilogov, Vsevolod

    2013-04-01

    For a long time as a most convenient had been the model of mega impact in which the early forming of the Earth's core and mantle had been the consequence of formed protoplanet collision with the body of Mercurial mass. But all dynamical models of the Earth's accumulation and the estimations after the Pb-Pb system, lead to the conclusion that the duration of the planet accumulation was about 1 milliard years. But isotopic results after the W-Hf system testify about a very early (5-10) million years, dividing of the geochemical reservoirs of the core and mantle. In [1,3] it is shown, that the account of energy dissipating by the decay of short living radioactive elements and first of all Al,it is sufficient for heating even small bodies with dimensions about (50-100) km up to the iron melting temperature and can be realized a principal new differentiation mechanism. The inner parts of the melted preplanets can join and they are mainly of iron content, but the cold silicate fragments return to the supply zone. Only after the increasing of the gravitational radius, the growing area of the future core can save also the silicate envelope fragments. All existing dynamical accumulation models are constructed by using a spherical-symmetrical model. Hence for understanding the further planet evolution it is significant to trace the origin and evolution of heterogeneities, which occur on the planet accumulation stage. In that paper we are modeling distributions of temperature, pressure, velocity of matter flowing in a block of 3D- spherical body with a growing radius. The boundary problem is solved by the finite-difference method for the system of equations, which include equations which describe the process of accumulation, the Safronov equation, the equation of impulse balance, equation Navier-Stocks, equation for above litho static pressure and heat conductivity in velocity-pressure variables using the Businesque approach. The numerical algorithm of the problem solution in

  3. [Blood trace elements content in adolescents in an industrial town].

    PubMed

    Namazbaeva, Z I; Amanzhol, I A; Shibuchikova, Zh B; Sabirov, Zh B; Zhumabekova, S Zh

    2013-01-01

    A cohort blind study of blood trace elements content in children-adolescents aged 14-16 years old, residing in an industrial town, where large industrial enterprises of ferrous and non-ferrous metallurgy have been functioning for long periods, has been performed There was established a lack of vital important element selenium in the blood, that causes the accumulation of toxic metals, cadmium and mercury.

  4. A comparative study of the elemental composition of the exhaust emissions of cars powered by liquefied petroleum gas and unleaded petrol

    NASA Astrophysics Data System (ADS)

    Lim, McKenzie C. H.; Ayoko, Godwin A.; Morawska, Lidia; Ristovski, Zoran D.; Jayaratne, E. Rohan; Kokot, Serge

    Elements emitted from the exhausts of new Ford Falcon Forte cars powered by unleaded petrol (ULP) and liquefied petroleum gas (LPG) were measured on a chassis dynamometer. The measurements were carried out in February, June and August 2001, and at two steady state driving conditions (60 and 80 km h -1). Thirty seven elements were quantified in the exhaust samples by inductively coupled plasma mass spectrometry (ICPMS). The total emission factors of the elements from the exhausts of ULP cars were higher than those of LPG cars at both engine speeds even though high variability in the exhaust emissions from different cars was noted. The effect of the operating conditions such as mileage of the cars, engine speed, fuel and lubricating oil compositions on the emissions was studied. To investigate the effects of these conditions, multivariate data analysis methods were employed including exploratory principal component analysis (PCA), and the multi-criteria decision making methods (MCDM), preference ranking organization method for enrichment evaluation (PROMETHEE) and geometrical analysis for interactive aid (GAIA), for ranking the cars on the basis of the emission factors of the elements. PCA biplot of the complete data matrix showed a clear discrimination of the February, June and August emission test results. In addition, (i) platinum group elements (PGE) emissions were separated from each other in the three different clusters viz. Pt with February, Pd with June and Rh with August; (ii) the motor oil related elements, Zn and P, were particularly associated with the June and August tests (these vectors were also grouped with V, Al and Cu); and (iii) highest emissions of most major elements were associated with the August test after the cars have recorded their highest mileage. Extensive analysis with the aid of the MCDM ranking methods demonstrated clearly that cars powered by LPG outperform those powered by ULP. In general, cars tested in June perform better than

  5. Reevaluation of siderophile element abundances and ratios across the Cretaceous-Paleogene (K-Pg) boundary: Implications for the nature of the projectile

    NASA Astrophysics Data System (ADS)

    Goderis, S.; Tagle, R.; Belza, J.; Smit, J.; Montanari, A.; Vanhaecke, F.; Erzinger, J.; Claeys, Ph.

    2013-11-01

    The discovery over 30 years ago at Gubbio (Italy) and Caravaca (Spain) of an enrichment in the concentrations of iridium (Ir) and the other platinum group elements (PGE) by up to four orders of magnitude (Irmax = 0.10-87 ng/g) compared to average continental crustal background levels remains one of the most important discoveries in the Earth sciences. Since then, similar anomalies have been detected in more than 120 Cretaceous-Paleogene (K-Pg) boundary sites worldwide. Highly elevated Ir and other siderophile element abundances in roughly chondritic ratios are considered strong indicators for the presence of a meteoritic contribution in impact-related lithologies (melt rocks, impact ejecta material, etc.), delivered when an extraterrestrial object strikes Earth. The presented work adds 113 unpublished PGE analyses of 38 K-Pg sections worldwide to the existing literature. The analytical protocol relied on for this purpose consisted of a combination of a nickel-sulfide fire assay pre-concentration technique and subsequent trace metal determination via inductively coupled plasma-mass spectrometry (ICP-MS). Through repeated determination of key siderophile elements (i.e., Cr, Co, Ni, and PGE), the importance of sampling, nugget effects, and analytical methodologies applied becomes more apparent. Even more critically, these analytical effects are superimposed by the local syn- and post-depositional conditions that have affected the pristine meteoritic signature of the K-Pg impactor, including potential fractionation during vaporization and condensation, dissimilar PGE carrier phases, terrestrial PGE input, sedimentation rate, reworking, diagenesis, bioturbation, and chemical diffusion. While chondrite-normalized PGE patterns of individual sites appear relatively flat (i.e., chondritic), strong variations in siderophile element content and inter-element ratios exist between K-Pg locations, inter-laboratory measurements, and replicate analyses, hampering a precise

  6. Selective constraints on P-element evolution.

    PubMed

    Witherspoon, D J

    1999-04-01

    P elements, like mariners, inhabit eukaryotic genomes and transpose via a DNA intermediate. Mutant and wild-type elements in the same genome should be transposed with equal probability by trans-acting transposase, and so no selection should counteract the accumulation of inactivating mutations in transposase genes. Thus, copies of mariner elements diverge within a host species under no selection (Robertson and Lampe 1995). It is unknown whether or not this pattern holds for P elements, which are unrelated to mariner elements but share the same life history. Publicly available P-element sequences were analyzed for evidence of conservative selection for the function of P-element-encoded proteins. Results were compared to predictions derived from several hypotheses that could explain selection, or the lack of it. P-element protein-coding sequences do evolve under conservative selection but apparently because of more than one selective force. Of the four exons in the P-element transposase, the first three (exons 0, 1, and 2) can be translated alone into a repressor of transposition, while the last (exon 3) is only expressed as part of the full-length transposase and probably serves a transposition-specific role. As full-length P-element copies diverge from each other within a host population, selection maintains exons 0-2 but apparently not exon 3. The selection acting on exons 0-2 may act at the host level for repression of transposition (since host level selection does act on orthologous truncated elements that contain only exons 0-2). Evidence of selection on exon 3 is only found in comparisons of more diverged elements from different species, suggesting that selection for transposition acts primarily at horizontal transfer events. Thus, horizontal transfer events may be the sole source of the selection that is crucial to the maintenance of autonomous P elements in the face of mutation (as suggested by Robertson and Lampe 1995). The predictions derived here suggest

  7. Accumulation of swimming bacteria near an interface

    NASA Astrophysics Data System (ADS)

    Tang, Jay; Li, Guanglai

    2012-11-01

    Microbes inhabit planet earth over billions of years and have adapted to diverse physical environment of water, soil, and particularly at or near interfaces. We focused our attention on the locomotion of Caulobacter crescentus, a singly flagellated bacterium, at the interface of water/solid or water/air. We measured the distribution of a forward swimming strain of C. crescentus near a surface using a three-dimensional tracking technique based on dark field microscopy and found that the swimming bacteria accumulate heavily within a micrometer from the surface. We attribute this accumulation to frequent collisions of the swimming cells with the surface, causing them to align parallel to the surface as they continually move forward. The extent of accumulation at the steady state is accounted for by balancing alignment caused by these collisions with rotational Brownian motion of the micrometer-sized bacteria. We performed a simulation based on this model, which reproduced the measured results. Additional simulations demonstrate the dependence of accumulation on swimming speed and cell size, showing that longer and faster cells accumulate more near a surface than shorter and slower ones do. The overarching goal of our study is to describe interfacial microbial behavior through detailed analysis of their motion. We acknowledge support by NSF PHY 1058375.

  8. Geomorphic control of landscape carbon accumulation

    USGS Publications Warehouse

    Rosenbloom, N.A.; Harden, J.W.; Neff, J.C.; Schimel, D.S.

    2006-01-01

    We use the CREEP process-response model to simulate soil organic carbon accumulation in an undisturbed prairie site in Iowa. Our primary objectives are to identify spatial patterns of carbon accumulation, and explore the effect of erosion on basin-scale C accumulation. Our results point to two general findings. First, redistribution of soil carbon by erosion results in a net increase in basin-wide carbon storage relative to a noneroding environment. Landscape-average mean residence times are increased in an eroding landscape owing to the burial/preservation of otherwise labile C. Second, field observations taken along a slope transect may overlook significant intraslope variations in carbon accumulation. Spatial patterns of modeled deep C accumulation are complex. While surface carbon with its relatively short equilibration time is predictable from surface properties, deep carbon is strongly influenced by the landscape's geomorphic and climatic history, resulting in wide spatial variability. Convergence and divergence associated with upland swales and interfluves result in bimodal carbon distributions in upper and mid slopes; variability in carbon storage within modeled mid slopes was as high as simulated differences between erosional shoulders and depositional valley bottoms. The bimodality of mid-slope C variability in the model suggests that a three-dimensional sampling strategy is preferable over the traditional two-dimensional analog or "catena" approach. Copyright 2006 by the American Geophysical Union.

  9. Acetate limitation and nitrite accumulation during denitrification

    SciTech Connect

    Oh, J.; Silverstein, J.

    1999-03-01

    Nitrite accumulated in denitrifying activated sludge mixed liquor when the carbon and electron source, acetate, was limited. If acetate was added to obtain a carbon-to-nitrogen (C:N) ratio in the range of 2:1 to 3:1, nitrate was completely consumed at the same rate with no nitrite accumulation, indicating that nitrate concentration controlled the respiration rate as long as sufficient substrate was present. However, when acetate was reduced to a C:N ratio of 1:1, while nitrate continued to be consumed, > 50% of the initial nitrate-nitrogen accumulated as nitrite and 29% persisted as nitrite throughout an endogenous denitrification period of 8--9 h. While nitrite accumulated during acetate-limited denitrification, the specific nitrate reduction rate increased significantly compared with the rate when excess acetate was provided as follows: 0.034 mg-NO{sub 3}-N/mg-mixed liquid volatile suspended solids/h versus 0.023 mg-NO{sub 3}-N/mg-mixed liquid volatile suspended solids/h, respective. This may be explained by nitrate respiration out-competing nitrite respiration for limited acetate electrons. Complete restoration of balanced denitrification and elimination of nitrite accumulation during denitrification required several weeks after the C:N ratio was increased back to 2:1.

  10. Effects of cadmium on uptake and translocation of nutrient elements in different welsh onion (Allium fistulosum L.) cultivars.

    PubMed

    Li, Xuhui; Zhou, Qixing; Sun, Xiaoyin; Ren, Wenjie

    2016-03-01

    The concentration of nutrient elements is an important quality characteristic of vegetables, and the variation in accumulation among cultivars can provide clues about the mechanism of low accumulation of heavy metals. Pot-culture experiments were arranged under four cadmium (Cd) treatments (CK, 1.0, 2.5 and 5.0mg/kg) to explore influences of Cd on the accumulation of nutrient elements in 25 welsh onion cultivars. There were significant positive correlations (p<0.05) between Cd and nutrient elements in the pseudostems and leaves. There were also significant positive correlations in nutrient elements (p<0.05) among cultivars, which might be disturbed under high Cd treatments, especially for P, Fe and Mn. Our results suggested that there is a synergistic effect on the accumulation between Cd and nutrient elements, and within nutrient elements among cultivars. In addition the uptake and translocation process of Cd was closely related to Mn in welsh onion. PMID:26471532

  11. Effects of cadmium on uptake and translocation of nutrient elements in different welsh onion (Allium fistulosum L.) cultivars.

    PubMed

    Li, Xuhui; Zhou, Qixing; Sun, Xiaoyin; Ren, Wenjie

    2016-03-01

    The concentration of nutrient elements is an important quality characteristic of vegetables, and the variation in accumulation among cultivars can provide clues about the mechanism of low accumulation of heavy metals. Pot-culture experiments were arranged under four cadmium (Cd) treatments (CK, 1.0, 2.5 and 5.0mg/kg) to explore influences of Cd on the accumulation of nutrient elements in 25 welsh onion cultivars. There were significant positive correlations (p<0.05) between Cd and nutrient elements in the pseudostems and leaves. There were also significant positive correlations in nutrient elements (p<0.05) among cultivars, which might be disturbed under high Cd treatments, especially for P, Fe and Mn. Our results suggested that there is a synergistic effect on the accumulation between Cd and nutrient elements, and within nutrient elements among cultivars. In addition the uptake and translocation process of Cd was closely related to Mn in welsh onion.

  12. Chemistry of superheavy elements.

    PubMed

    Schädel, Matthias

    2006-01-01

    The number of chemical elements has increased considerably in the last few decades. Most excitingly, these heaviest, man-made elements at the far-end of the Periodic Table are located in the area of the long-awaited superheavy elements. While physical techniques currently play a leading role in these discoveries, the chemistry of superheavy elements is now beginning to be developed. Advanced and very sensitive techniques allow the chemical properties of these elusive elements to be probed. Often, less than ten short-lived atoms, chemically separated one-atom-at-a-time, provide crucial information on basic chemical properties. These results place the architecture of the far-end of the Periodic Table on the test bench and probe the increasingly strong relativistic effects that influence the chemical properties there. This review is focused mainly on the experimental work on superheavy element chemistry. It contains a short contribution on relativistic theory, and some important historical and nuclear aspects.

  13. Cohesive Elements for Shells

    NASA Technical Reports Server (NTRS)

    Davila, Carlos G.; Camanho, Pedro P.; Turon, Albert

    2007-01-01

    A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design.

  14. The synthetic elements

    SciTech Connect

    Hoffman, D.C.

    1990-05-01

    Prior to 1940, the heaviest element known was uranium, discovered in 1789. Since that time the elements 93 through 109 have been synthesized and identified and the elements 43, 61, 85, and 87 which were missing form the periodic tables of the 1930's have been discovered. The techniques and problems involved in these discoveries and the placement of the transuranium elements in the periodic table will be discussed. The production and positive identification of elements heavier than Md (Z=101), which have very short half-lives and can only be produced an atom-at-a-time, are very difficult and there have been controversies concerning their discovery. Some of the new methods which have been developed and used in these studies will be described. The prospects for production of still heavier elements will be considered.

  15. The effects of aluminium on plant growth in a temperate and deciduous aluminium accumulating species

    PubMed Central

    Schmitt, Marco; Watanabe, Toshihiro; Jansen, Steven

    2016-01-01

    Aluminium (Al) is a phytotoxic element affecting the growth and yield of many crop plants, especially in the tropics. Yet, some plants are able to accumulate high levels of Al. The monogeneric family Symplocaceae represents an Al accumulating family including many tropical and evergreen species with high Al levels in their above ground plant tissues. It is unclear, however, whether Al accumulation also characterises temperate species of Symplocos, and whether or not the uptake has a beneficial growth effect. Here, we investigate if the temperate, deciduous species Symplocos paniculata is able to accumulate Al by growing seedlings and saplings in a hydroponic setup at pH 4 with and without Al. Pyrocatechol-violet (PCV) and aluminon staining was performed to visualize Al accumulation in various plant tissues. Both seedlings and saplings accumulate Al in their tissues if available. Mean Al levels in leaves were 4107 (±1474 mg kg−1) and 4290 (±4025 mg kg−1) for the seedlings and saplings, respectively. The saplings treated without Al showed a high mortality rate unlike the Al accumulating ones. The seedlings, however, showed no difference in growth and vitality between the two treatments. The saplings treated with Al showed new twig, leaf and root development, resulting in a considerable biomass increase. PCV and aluminon staining indicated the presence of Al in leaf, wood and bark tissue of the plants. S. paniculata shares the capacity to accumulate Al with its tropical sister species and is suggested to be a facultative accumulator. Whether or not Al has a beneficial effect remains unclear, due to developmental differences between seedlings and saplings. Al is suggested to be transported via the xylem transport system into the leaves, which show the highest Al levels. Radial transport via ray parenchyma to bark tissue is also likely given the high Al concentrations in the bark tissue. PMID:27613876

  16. NEUTRONIC REACTOR CONTROL ELEMENT

    DOEpatents

    Newson, H.W.

    1960-09-13

    A novel composite neutronic reactor control element is offered. The element comprises a multiplicity of sections arranged in end-to-end relationship, each of the sections having a markedly different neutron-reactive characteristic. For example, a three-section control element could contain absorber, moderator, and fuel sections. By moving such an element longitudinally through a reactor core, reactivity is decreased by the absorber, increased slightly by the moderator, or increased substantially by the fuel. Thus, control over a wide reactivity range is provided.

  17. Plants accumulating heavy metals in the Danube River wetlands

    PubMed Central

    2013-01-01

    Background We present herein our results regarding the accumulation of four heavy metals (copper, cadmium, lead, and zinc) in four aquatic species plants (Ceratophyllum demersum, Potamogeton pectinatus, Potamogeton lucens, Potamogeton perfoliatus) collected from the Danube River, South-Western part of Romania and their possible use as indicators of aquatic ecosystems pollution with heavy metals. Methods Elements concentration from the vegetal material was determined through Inductively Coupled Plasma – Mass Spectrometry. Results The species were chosen based on their previous use as bioindicators in aquatic ecosystems and due to the fact they are one of the most frequent aquatic plant species of the Danube River ecosystems within the Iron Gates Natural Park. Highest amounts are recorded for Ceratophyllum demersum (3.52 μg/g for Cd; 22.71 μg/g for Cu; 20.06 μg/g for Pb; 104.23 μg/g for Zn). Among the Potamogeton species, the highest amounts of heavy metals are recorded in Potamogeton perfoliatus (1.88 μg/g for Cd; 13.14 μg/g for Cu; 13.32 μg/g for Pb; 57.96 μg/g for Zn). The sequence for the bioconcentration factors (BCFs) calculated in order to describe the accumulation of the four metals is Cd >> Zn > Pb > Cu. Increase of the zinc concentration determines an increase of the cadmium concentration (Spearman rho=0.40, p=0.02). Conclusions Despite the low ambiental levels of heavy metals, the four aquatic plants have the ability to accumulate significant amounts, which make them useful as biological indicators. BCF value for Ceratophyllum demersum indicated this species as a cadmium hyperaccumulator. PMID:24359799

  18. Comprehensive model of damage accumulation in silicon

    SciTech Connect

    Mok, K. R. C.; Benistant, F.; Jaraiz, M.; Rubio, J. E.; Castrillo, P.; Pinacho, R.; Srinivasan, M. P.

    2008-01-01

    Ion implantation induced damage accumulation is crucial to the simulation of silicon processing. We present a physically based damage accumulation model, implemented in a nonlattice atomistic kinetic Monte Carlo simulator, that can simulate a diverse range of interesting experimental observations. The model is able to reproduce the ion-mass dependent silicon amorphous-crystalline transition temperature of a range of ions from C to Xe, the amorphous layer thickness for a range of amorphizing implants, the superlinear increase in damage accumulation with dose, and the two-layered damage distribution observed along the path of a high-energy ion. In addition, this model is able to distinguish between dynamic annealing and post-cryogenic implantation annealing, whereby dynamic annealing is more effective in removing damage than post-cryogenic implantation annealing at the same temperature.

  19. Cohabitation history, marriage, and wealth accumulation.

    PubMed

    Vespa, Jonathan; Painter, Matthew A

    2011-08-01

    This study extends research on the relationship between wealth accumulation and union experiences, such as marriage and cohabitation. Using data from the National Longitudinal Survey of Youth 1979, we explore the wealth trajectories of married individuals in light of their premarital cohabitation histories. Over time, marriage positively correlates with wealth accumulation. Most married persons with a premarital cohabitation history have wealth trajectories that are indistinguishable from those without cohabitation experience, with one exception: individuals who marry their one and only cohabiting partner experience a wealth premium that is twice as large as that for married individuals who never cohabited prior to marrying. Results remain robust over time despite cohabiters' selection out of marriage, yet vary by race/ethnicity. We conclude that relationship history may shape long-term wealth accumulation, and contrary to existing literature, individuals who marry their only cohabiting partners experience a beneficial marital outcome. It is therefore important to understand the diversity of cohabitation experiences among the married.

  20. Competition between transposable elements and mutator genes in bacteria.

    PubMed

    Fehér, Tamás; Bogos, Balázs; Méhi, Orsolya; Fekete, Gergely; Csörgo, Bálint; Kovács, Károly; Pósfai, György; Papp, Balázs; Hurst, Laurence D; Pál, Csaba

    2012-10-01

    Although both genotypes with elevated mutation rate (mutators) and mobilization of insertion sequence (IS) elements have substantial impact on genome diversification, their potential interactions are unknown. Moreover, the evolutionary forces driving gradual accumulation of these elements are unclear: Do these elements spread in an initially transposon-free bacterial genome as they enable rapid adaptive evolution? To address these issues, we inserted an active IS1 element into a reduced Escherichia coli genome devoid of all other mobile DNA. Evolutionary laboratory experiments revealed that IS elements increase mutational supply and occasionally generate variants with especially large phenotypic effects. However, their impact on adaptive evolution is small compared with mismatch repair mutator alleles, and hence, the latter impede the spread of IS-carrying strains. Given their ubiquity in natural populations, such mutator alleles could limit early phase of IS element evolution in a new bacterial host. More generally, our work demonstrates the existence of an evolutionary conflict between mutation-promoting mechanisms.

  1. [Accumulation of heavy metals in the sediments of Shenzhen Bay, south China].

    PubMed

    Huang, Xiaoping; Li, Xiangdong; Yue, Weizhong; Huang, Liangmin; Li, Yoksheung

    2003-07-01

    Heavy metals concentrations in marine sediment cores of Shenzhen Bay were measured, and the profile distribution characteristic of heavy metals was discussed. Combined with the 210 Pb dating results, the contamination history of heavy metals was studied in high resolution records, and the metal accumulation processes were also analyzed. The results indicated that the concentrations of heavy metals was relatively low compared with other area in the world, but the elements of Pb, Cu and Zn were obviously contaminated by anthropogenic impact. The rapid economical development of Shenzhen in the last 20 years and Hong Kong in 1960-1970s contributed much on accumulation of heavy metals in the sediments.

  2. Landscape Evolution and Carbon Accumulation: Uniformitarianism Revisited

    NASA Astrophysics Data System (ADS)

    Rosenbloom, N. A.; Harden, J. W.; Neff, J. C.; Schimel, D. S.

    2003-12-01

    What is the role of hillslope transport in long-term carbon accumulation in soils? How do parent material, climate, and landform interact to produce the landscapes we observe today and to what extent can we use present day conditions to infer the dominant processes of the past? We use the CREEP [Rosenbloom, N.A. et al., 2001] process-response model to ask these questions, exploring the time-evolution of landscape form, soil distribution, and carbon accumulation in an undisturbed prairie site in western Iowa [Harden, J.W. et al., 2002]. The CREEP model simulates differential transport of soil particles, blanket deposition of atmospheric 10Be with eolian dust, and passive advection of soil carbon and 10Be, enabling the preferential enrichment and burial of rapidly moving soil constituents. By comparing landscape-wide average accumulations of 10Be to borehole observations at three hillslope positions, we conclude that the distribution of clay-adsorbed 10Be cannot be explained by co-transport with clay particles alone. Rather, 10Be appears to behave as a more complex tracer than originally assumed, requiring an explicit, independent parameterization of wet deposition and transport. By comparison, model carbon accumulation strongly reflects patterns of clay redistribution indicating that in situ carbon turnover is faster than redistribution. Observed vertical distributions of soil properties, including 10Be, could only be explained by assuming variations in deposition and erosion rates, specifically periods of accumulation, followed by periods of transport. This effect might not be apparent if only landform shape, geometry, and soil depth were considered and vertical distributions of soil properties were not explicitly simulated. The current landscape reflects a history of strong shifts in erosion and accumulation rates that cannot be simulated using a uniform parameterization of long-term landscape-evolution processes.

  3. Spatial distribution of heavy metal accumulation in the sediments after dam construction.

    PubMed

    Shim, Moo Joon; Yang, Yun Mo; Oh, Da Yeon; Lee, Soo Hyung; Yoon, Yi Yong

    2015-12-01

    The sedimentary environment has been modified in the Geum River where an estuary dam and midstream dams were constructed. Furthermore, the Geum River tributaries deliver contaminants from the wastewater of an industrial complex. However, the influence of tributaries and dams on sedimentary metal deposition has not been extensively studied. The objectives of this study are to assess metal accumulation and to investigate the source of the metals. Sediments were collected in the main channel and two tributaries on October 2013. Abnormal accumulations of fine sediments were not observed above the midstream dams. Chromium, Ni, and Zn showed higher concentrations in above the midstream dam, but their concentrations were not related to grain size. Cadmium, Cu, Pb, and Hg were much higher upstream from the first midstream dam and came from one of the major tributaries. Arsenic was the only element found at higher concentrations downstream from the last midstream dam and was likely sourced from abandoned mines and/or agricultural activity. The pollution indexes indicated deposition of all metals, except Cr and Ni, may have been affected by anthropogenic activity. With respect to long-term accumulation of the metals, accumulation of Pb, Zn, and Cu by anthropogenic input largely increased, implying accumulation of these metals has continued due to anthropogenic activity since the estuary dam was constructed. Our results suggest that changes in river flow caused by the estuary dam and anthropogenic input from tributaries sources increased the accumulation of heavy metals (e.g., Pb, Zn, Cu, and As). PMID:26549487

  4. Spatial distribution of heavy metal accumulation in the sediments after dam construction.

    PubMed

    Shim, Moo Joon; Yang, Yun Mo; Oh, Da Yeon; Lee, Soo Hyung; Yoon, Yi Yong

    2015-12-01

    The sedimentary environment has been modified in the Geum River where an estuary dam and midstream dams were constructed. Furthermore, the Geum River tributaries deliver contaminants from the wastewater of an industrial complex. However, the influence of tributaries and dams on sedimentary metal deposition has not been extensively studied. The objectives of this study are to assess metal accumulation and to investigate the source of the metals. Sediments were collected in the main channel and two tributaries on October 2013. Abnormal accumulations of fine sediments were not observed above the midstream dams. Chromium, Ni, and Zn showed higher concentrations in above the midstream dam, but their concentrations were not related to grain size. Cadmium, Cu, Pb, and Hg were much higher upstream from the first midstream dam and came from one of the major tributaries. Arsenic was the only element found at higher concentrations downstream from the last midstream dam and was likely sourced from abandoned mines and/or agricultural activity. The pollution indexes indicated deposition of all metals, except Cr and Ni, may have been affected by anthropogenic activity. With respect to long-term accumulation of the metals, accumulation of Pb, Zn, and Cu by anthropogenic input largely increased, implying accumulation of these metals has continued due to anthropogenic activity since the estuary dam was constructed. Our results suggest that changes in river flow caused by the estuary dam and anthropogenic input from tributaries sources increased the accumulation of heavy metals (e.g., Pb, Zn, Cu, and As).

  5. Elemental Food for Thought

    ERIC Educational Resources Information Center

    Cady, Susan

    2005-01-01

    One of the first tasks students learn in chemistry is to pronounce and spell the names of elements and learn their corresponding chemical symbols. Repetitive oral recitation is commonly used to learn this information, but games and puzzles can make this task creative, variable, and fun. Elemental Food for Thought is a puzzlelike activity that…

  6. MOLDED SEALING ELEMENT

    DOEpatents

    Bradford, B.W.; Skinner, W.J.

    1959-03-24

    Molded sealing elements suitable for use under conditions involving exposure to uranium hexafluoride vapor are described. Such sealing elements are made by subjecting graphitic carbons to a preliminary treatment with uranium hexafluoride vapor, and then incorporating polytetrafluorethylene in them. The resulting composition has good wear resistant and frictional properties and is resistant to disintegration by uranium hexafluoride over long periods of exposure.

  7. The Elements Drawing.

    ERIC Educational Resources Information Center

    Dkeidek, Iyad M.

    2003-01-01

    Presents an educational game designed for first- or second-year high school students who have already studied themes related to the periodic table elements, such as their symbols, electronic configurations, properties, and uses. The game is designed to help students learn the symbols of the elements and their properties or uses in a fun, engaging…

  8. Automatic finite element generators

    NASA Technical Reports Server (NTRS)

    Wang, P. S.

    1984-01-01

    The design and implementation of a software system for generating finite elements and related computations are described. Exact symbolic computational techniques are employed to derive strain-displacement matrices and element stiffness matrices. Methods for dealing with the excessive growth of symbolic expressions are discussed. Automatic FORTRAN code generation is described with emphasis on improving the efficiency of the resultant code.

  9. Movies and Literary Elements.

    ERIC Educational Resources Information Center

    Keller, Rodney D.

    Showing ten-minute movie clips can be an effective way to motivate students to read literature and to teach elements of fiction, namely plot, character, setting, symbol, irony, and theme. A clip from "And Then There Were None" may be used to teach various elements of plot, including conflict and the four types of conflict (man vs. man, man vs.…