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This report summarizes the results of a study carried out on six pulverized coal-fired power plants in western Canada burning subbituminous coal for the mass-balance and speciation of mercury. The main objectives of this study were to: determine the total gaseous mercury (TGM) emitted from stacks of power plants using the Ontario Hydro method; identify the speciation of emitted mercury such as metallic (Hg(0)) and gaseous elemental (GEM) mercury; and perform mass-balance calculations of mercury for milled-coal, bottom ash, electrostatic precipitators (ESP) fly ash and stack-emitted mercury based on three tests. Sampling of mercury was carried out using the Ontario Hydro method and mercury was determined using the USEPA method 7473 by cold vapor atomic absorption (CVAAS). The sample collection efficiencies confirmed that both oxidized and the elemental mercury had been successfully sampled at all power plants. The total gaseous mercury emitted (TGM) is 6.95-15.66 g h(-1) and is mostly in gaseous elemental mercury (GEM, Hg(0)) form. The gaseous elemental mercury is emitted at a rate of 6.59-12.62 g h(-1). Reactive gaseous mercury (RGM, Hg(2+)) is emitted at a rate of 0.34-3.68 g h(-1). The rate of emission of particulate mercury (Hg(p)) is low and is in the range 0.005-0.076 g h(-1). The range of mass-balances for each power plant is more similar to the variability in measured mercury emissions, than to the coal and ash analyses or process data. The mass-balance calculations for the six power plants, performed on results of the three tests at each power plant, are between 86% and 123%, which is acceptable and within the range 70-130%. The variation in mass-balance of mercury for the six power plants is mostly related to the variability of coal feed rate.
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PMID:Speciation and mass-balance of mercury from pulverized coal fired power plants burning western Canadian subbituminous coals. 1548 Apr 92

Starch isolated from hybrid maize (8535-23) was subjected to oxidation and acid thinning. Proximate analyses revealed that moisture, ash, protein, fat, fibre, and pH reduced after oxidation and acid thinning. Percentage amylose content reduced from 20.42% in native starch to 18.76 and 17.65% in oxidised and acid thinned starch derivatives, respectively. Wide-angle X-ray diffraction patterns indicated strong peaks at 15.9 degrees, 17.2 degrees, 18.8 degrees, and 25.0 degrees 2theta. No significant difference was observed between the X-ray pattern of the native and modified starches. Both swelling power and solubility increased with increase in temperature. Oxidation and acid thinning reduced swelling power and increased solubility starch. At all pHs, both oxidation and acid thinning reduced the swelling capacity of the native starch. Oxidation increased water and oil absorption capacity of the native starch, while both hydrophilic and hydrophobic properties reduced following acid thinning. Least gelation concentration reduced in acid thinned starch but increased in oxidised derivative. Pasting temperature (Tp), peak viscosity (Pv), hot paste viscosity (Hv), and viscosity after 30 min holding at 95 degrees C (H(v30)) reduced following both modifications. However, values for cold paste viscosity (Cv) and setback (SB) reduced in oxidised derivative and increased in acid thinned starch. Light transmittance of the starch pastes reduced with increase in storage days, however, reduction was more pronounced in native and acid thinned starches. Onset temperature (To), peak temperature (Tp) and conclusion temperature (Tc) of gelatinisation reduced in modified starches compared with native hybrid maize starch. Also, gelatinisation enthalpy reduced after oxidation and acid thinning. Enthalpy of regelatinisation increased as days of storage of starch paste increased.
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PMID:Oxidized and acid thinned starch derivatives of hybrid maize: functional characteristics, wide-angle X-ray diffractometry and thermal properties. 1576 18

The main purpose of this study was to develop a cryopreservation protocol for ash and to highlight the importance of testing different clones and plant material of different ontogenetic states. In vitro-grown ash (Fraxinus excelsior L.) shoot tips were successfully cryopreserved following optimization of the PVS2-vitrification protocol. Pretreatment conditions were optimized and three cryopreservation techniques (encapsulation/dehydration, PVS2-vitrification and encapsulation-vitrification) were tested one after another. PVS2-vitrification proved to be the most suitable technique. In vitro-grown shoot tips of ash were successfully cryopreserved with a mean regrowth of 73% for juvenile clones and 67% for selected mature trees. The optimum preculture conditions and the initial protocol were: 10 days cold hardening, preculture for 2 days on medium with 0.8 M glycerol, incubation in 2 M glycerol solution for 20 min at 22 degrees C followed by PVS2 for 25 min at 0 degrees C on ice and direct immersion in liquid nitrogen. Warming was carried out in 43 degree C water for 1 min followed by 22 degree C water for 10 sec. The encapsulation/dehydration method was not successful for shoot tips of F. excelsior because the shoots were sensitive to osmotic dehydration. The encapsulation/vitrification method resulted in a mean regrowth of only 16%. PVS2 vitrification can now be used to store important ash germplasm of either juvenile or mature trees.
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PMID:Comparison of cryopreservation techniques for long-term storage of ash (Fraxinus excelsior L.). 1608 46

Transport of indoleacetic acid-1(14)C following application to the buds of intact white ash (Fraxinus americana L.) shoots proceeds at a velocity of about 1.3 centimeters per hour in actively growing seedlings, but only 0.3 centimeter per hour in dormant seedlings. The rapid movement is metabolically controlled, and at 1 C or in a nitrogen environment it is reduced to 0.2 centimeter per hour, suggesting that the slower movement is due to diffusion. The transport profile for growing shoots shows a logarithmic decrease in activity in stems treated for 3 hours. However, over longer treatment intervals, especially after 12 hours, a steady state of recoverable activity occurs in the more basal stem segments. Cold-treated shoots acquire the capacity for rapid transport 7 days after they are placed into favorable growing conditions, at which time dormancy callose disappears from the phloem, respiratory activity of the stem tissue increases, and mitotic reactivation occurs in the bud. Following shoot reactivation, the velocity and amount of exogenously supplied indoleacetic acid transported remained relatively uniform until the onset of the succeeding dormant period. Five per cent, or less, of the applied tracer moves into the shoot, with substantial portions remaining as indoleacetic acid.
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PMID:Auxin Transport within Intact Dormant and Active White Ash Shoots. 1665 52

In the present study the environmental effects on herbivores mammals in and around Coal-fired power plant were studied by collecting the various milk samples of Cow and Buffalo in clean polyethylene bottles. Milk samples collected at five different locations along the banks of the Paravanaru river in and around Neyveli area. These samples were prepared for trace metal determination. The concentration of trace metals (Cu, Zn, Ni, Cd, Cr, Mn, Co and Hg) were determined by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and Cold Vapour Atomic Absorption Spectrometry (CVAAS). It is observed that the samples contain greater amounts of trace metals than that in the unexposed areas. Obviously the milk samples are contaminated with these metals due to fly ash released in such environment.
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PMID:Determination of trace elements in dairy milk collected from the environment of coal-fired power plant. 1666 36

We investigated range-wide phylogeographic variation in three European ash species (Fraxinus sp., Oleaceae). Chloroplast DNA (cpDNA) microsatellites were typed in the thermophilous Fraxinus angustifolia and Fraxinus ornus and the observed haplotypes and the geographic distribution of diversity were compared to cpDNA data previously obtained in the more cold-tolerant Fraxinus excelsior. We found wide-ranging haplotype sharing between the phylogenetically close F. angustifolia and F. excelsior, suggesting hybridization (i) in common glacial refuges in the Iberian Peninsula, northern Italy, the eastern and/or Dinaric Alps and the Balkan Peninsula, and/or (ii) during postglacial recolonization. The data allowed us to propose additional glacial refuges for F. angustifolia in southern Italy and in Turkey, and populations from the latter region were particularly polymorphic. There was evidence for refuge areas in Italy, the Balkan Peninsula and Turkey for F. ornus, which did not share any single chloroplast haplotype with the other species. In both F. angustifolia and F. ornus, cpDNA diversity (h(S) = 0.027 and h(S) = 0.009, respectively) was lower and fixation levels (G(ST) = 0.964 and G(ST) = 0.983, respectively) higher than in sympatric F. excelsior (h(S) = 0.096, G(ST) = 0.870). These diversity patterns could be due to temperature tolerance or the demographic history.
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PMID:Chloroplast DNA phylogeography of European ashes, Fraxinus sp. (Oleaceae): roles of hybridization and life history traits. 1678 Apr 30

Total suspended particle (TSP) concentrations were determined in the Eordea basin (western Macedonia, Greece), an area with intensive lignite burning for power generation. The study was conducted over a one-year period (November 2000-November 2001) at 10 sites located at variable distances from the power plants. Ambient TSP samples were analyzed for 27 major, minor and trace elements. Annual means of TSP concentrations ranged between 47+/-33 microg m(-3) and 110+/-50 microg m(-3) at 9 out of the 10 sites. Only the site closest to the power stations and the lignite conveyor belts exhibited annual TSP levels (210+/-97 microg m(-3)) exceeding the European standard (150 microg m(-3), 80/779/EEC). Concentrations of TSP and almost all elemental components exhibited significant spatial variations; however, the elemental profiles of TSP were quite similar among all sites suggesting that they are affected by similar source types. At all sites, statistical analysis indicated insignificant (P<0.05) seasonal variation for TSP concentrations. Some elements (Cl, As, Pb, Br, Se, S, Cd) exhibited significantly higher concentrations at certain sites during the cold period suggesting more intense emissions from traffic, domestic heating and other combustion sources. On the contrary, concentrations significantly higher in the warm period were found at other sites mainly for crustal elements (Ti, Mn, K, P, Cr, etc.) suggesting stronger influence from soil resuspension and/or fly ash in the warm months. The most enriched elements against local soil or road dust were S, Cl, Cu, As, Se, Br, Cd and Pb, whereas negligible enrichment was found for Ti, Mn, Mg, Al, Si, P, Cr. At most sites, highest concentrations of TSP and elemental components were associated with low- to moderate-speed winds favoring accumulation of emissions from local sources. Influences from the power generation were likely at those sites located closest to the power plants and mining activities.
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PMID:Trace elements in atmospheric particulate matter over a coal burning power production area of western Macedonia, Greece. 1682 78

Non-conventional nixtamalized maize flours elaborated by a factory in Mexico were used for tortilla preparation. Tortillas were stored at 4 degrees C for up to 72 h and the total starch, available starch, resistant starch and retrograded resistant starch were assessed. The traditional white tortilla, used as a control, showed higher protein and fat contents than blue maize tortilla, whereas a maize-bean mixed tortilla had the highest protein, ash and fat contents. Lower total starch was obtained in the maize-bean tortilla than in white and blue maize tortillas. The available starch content in all tortillas decreased with the cold-storage, although the change was more marked for blue-maize tortillas. The maize-bean mixed tortillas exhibited the lowest in vitro digestibility, which is consistent with the relatively high resistant starch levels in the bean. Differences in resistant starch content were found between the two maize tortillas, which might be related to the softer texture of blue-maize tortilla. The starch digestibility features of these new types of nixtamalized maize flours open up the possibility of producing tortillas with variable nutritional properties.
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PMID:Chemical composition and starch digestibility of tortillas prepared with non-conventional commercial nixtamalized maize flours. 1684 22

This paper discusses the geochemistry and mineralogy of the barkinite liptobiolith of the Late Permian age from the Jinshan Mine, Guangde County, Anhui Province, China. Samples were examined using inductively coupled plasma-mass spectroscopy, X-ray fluorescence, cold-vapor atomic absorption spectrometry, ion-selective electrode, sequential chemical extraction, scanning electron microscopy equipped with energy-dispersive X-ray, and optical microscopy. The coal is a medium-ash and high-sulfur resource. Minerals in the coal are composed of kaolinite, pyrite, calcite, and quartz. Pyrite and calcite are derived from seawater during peat accumulation. Quartz in the coal is of authigenic origin. Part of the kaolinite is from a land-source region, and part occurs as cell-fillings and is of authigenic origin. The results also indicate that the barkinite liptobiolith contains some toxic elements in high concentrations. Elements including Li, Be, Si, Sc, Ti, V, Cr, Fe, Ga, Se, Y, Zr, Mo, the rare earth elements (REEs), W, Hg, Tl, Pb, Th, and U in the coals are enriched in the barkinite liptobiolith. Results of sequential chemical extraction showed that Li, Sc, Ti, Cr, Y, Zr, REEs, and Th in the coal mainly occur as silicates, while Be and W are related to organic matter. Pyrite is the dominant source of S, Mo, Hg, Tl, and Pb. Gallium only occurs in silicate, and U and V occur both in organic and silicate associations.
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PMID:Geochemistry of the barkinite liptobiolith (Late Permian) from the Jinshan Mine, Anhui Province, China. 1720 70

A simple method was developed for the determination of mercury (Hg) in coal fly ash (CFA), waste incineration ash (WIA), and soil by use of oxygen flask combustion (OFC) followed by cold vapor atomic fluorescence spectrometry (CVAFS). A KMnO4 solution was used as an absorbent in the OFC method, and the sample containing a combustion agent and an ash or soil sample was combusted by the OFC method. By use of Hg-free graphite as the combustion agent, the determination of Hg in ash and soil was successfully carried out; the Hg-free graphite was prepared by use of a mild pyrolysis procedure at 500 degrees C. For six certified reference materials (three CFA samples and three soil samples), the values of Hg obtained by this method were in good agreement with the certified or reference values. In addition, real samples including nine CFAs collected from some coal-fired power plants, five WIAs collected from waste incineration plants, and two soils were analyzed by the present method, and the data were compared to those from microwave-acid digestion (MW-AD) method.
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PMID:Determination of mercury in ash and soil samples by oxygen flask combustion method--cold vapor atomic fluorescence spectrometry (CVAFS). 1802 28


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