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Sample records for natural waters acidic

  1. Organic acids in naturally colored surface waters

    USGS Publications Warehouse

    Lamar, William L.; Goerlitz, D.F.

    1966-01-01

    Most of the organic matter in naturally colored surface waters consists of a mixture of carboxylic acids or salts of these acids. Many of the acids color the water yellow to brown; however, not all of the acids are colored. These acids range from simple to complex, but predominantly they are nonvolatile polymeric carboxylic acids. The organic acids were recovered from the water by two techniques: continuous liquid-liquid extraction with n-butanol and vacuum evaporation at 50?C (centigrade). The isolated acids were studied by techniques of gas, paper, and column chromatography and infrared spectroscopy. About 10 percent of the acids recovered were volatile or could be made volatile for gas chromatographic analysis. Approximately 30 of these carboxylic acids were isolated, and 13 of them were individually identified. The predominant part of the total acids could not be made volatile for gas chromatographic analysis. Infrared examination of many column chromatographic fractions indicated that these nonvolatile substances are primarily polymeric hydroxy carboxylic acids having aromatic and olefinic unsaturation. The evidence suggests that some of these acids result from polymerization in aqueous solution. Elemental analysis of the sodium fusion products disclosed the absence of nitrogen, sulfur, and halogens.

  2. Adsorption of humic acids and trace metals in natural waters

    NASA Technical Reports Server (NTRS)

    Leung, W. H.

    1982-01-01

    Studies concerning the interactions between suspended hydrous iron oxide and dissolved humic acids and trace metals are reported. As a major component of dissolved organic matters and its readiness for adsorption at the solid/water interface, humic acids may play a very important role in the organometallic geochemistry of suspended sediments and in determining the fate and distribution of trace metals, pesticides and anions in natural water systems. Most of the solid phases in natural waters contain oxides and hydroxides. The most simple promising theory to describe the interactions of hydrous iron oxide interface is the surface complex formation model. In this model, the adsorptions of humic acids on hydrous iron oxide may be interpreted as complex formation of the organic bases (humic acid oxyanions) with surface Fe ions. Measurements on adsorptions were made in both fresh water and seawater. Attempts have been made to fit our data to Langmuir adsorption isotherm. Adsorption equilibrium constants were determined.

  3. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Stream water pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southwast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site. 10 references, 2 tables.

  4. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream-flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid-forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Streamwater pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by calcium, magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southeast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site.

  5. Stereoselective analysis of acid herbicides in natural waters by capillary electrophoresis.

    PubMed

    Polcaro, C M; Marra, C; Desiderio, C; Fanali, S

    1999-09-01

    A capillary electrophoretic method for the stereoselective analysis of aryloxypropionic and aryloxyphenoxypropionic acidic herbicides in ground water and river water was performed. Vancomycin and gamma-cyclodextrin were added to the background electrolyte (BGE) as chiral selectors. Water sample preconcentration was accomplished by solid-phase extraction on styrene-divinylbenzene packed cartridges (2 L of ground water and 1 L of river water). The analytical method allowed for the resolution of mecoprop, fenoprop, fluazifop and haloxyfop racemic mixtures in natural water samples spiked with enantiomer concentration levels in the range 0.1-0.13 ppb for ground water and 0.4-0.54 ppb for river water.

  6. Analysis of free amino acids in natural waters by liquid chromatography-tandem mass spectrometry.

    PubMed

    How, Zuo Tong; Busetti, Francesco; Linge, Kathryn L; Kristiana, Ina; Joll, Cynthia A; Charrois, Jeffrey W A

    2014-11-28

    This paper reports a new analytical method for the analysis of 18 amino acids in natural waters using solid-phase extraction (SPE) followed by liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) operated in multiple reaction monitoring mode. Two different preconcentration methods, solid-phase extraction and concentration under reduced pressure, were tested in development of this method. Although concentration under reduced pressure provided better recoveries and method limits of detection for amino acids in ultrapure water, SPE was a more suitable extraction method for real samples due to the lower matrix effects for this method. Even though the strong cation exchange resin used in SPE method introduced exogenous matrix interferences into the sample extracts (inorganic salt originating from the acid-base reaction during the elution step), the SPE method still incorporates a broad sample clean-up and minimised endogenous matrix effects by reducing interferences originating from real water samples. The method limits of quantification (MLQ) for the SPE LC-MS/MS method in ultrapure water ranged from 0.1 to 100 μg L(-1) as N for the different amino acids. The MLQs of the early eluting amino acids were limited by the presence of matrix interfering species, such as inorganic salts in natural water samples. The SPE LC-MS/MS method was successfully applied to the analysis of amino acids in 3 different drinking water source waters: the average total free amino acid content in these waters was found to be 19 μg L(-1) as N, while among the 18 amino acids analysed, the most abundant amino acids were found to be tyrosine, leucine and isoleucine.

  7. Chlorination of 4-hydroxycinnamic acid and its toxic risk as a natural occurring water contaminant

    SciTech Connect

    Borlakoglu, J.T.; Kickuth, R.

    1986-12-01

    During the decay process of plant material a number of phenolic compounds are released into the environment. Previous studies on water courses have shown that five phenolic acids derived from plants predominate with 4-hydroxycinnamic acid as the major compound. Many of these compounds can travel through the soil matrix and enter a water stream. However, water supplies are routinely chlorinated which leads to the chemical chlorination of phenolic water contaminants. These naturally occurring phenolics may therefore change their chemical and biological behavior and probably become, after chlorination, increasingly toxic. Although the occurrence of water compounds in tap water have been increasingly investigated with focus on industrial water pollutants, it is not fully understood to what extent the decay of plant material contributes to phenolic water contamination. Great concern about routine water chlorination has been expressed, because of the chlorination of aliphatic and aromatic water contaminants possibly accompanied by a change in their chemical and biological behavior and the synthesis of organochlorine derivatives. The present situation does not allow any prediction of the chemical and biological behavior of the parent compound nor is it possible to anticipate the amount and potential risk of its organochlorine derivatives. The objective of the present work was to study the chemical behavior of plant-derived phenolic acids under conditions similar to the routine water chlorination. The toxicity of the chlorophenoic mixtures was assessed on a Escherichia coli strain similar to that found in the human intestine.

  8. Impacts on water quality and biota from natural acid rock drainage in Colorado's Lake Creek watershed

    USGS Publications Warehouse

    Bird, D.A.; Sares, Matthew A.; Policky, Greg A.; Schmidt, Travis S.; Church, Stanley E.

    2006-01-01

    Colorado's Lake Creek watershed hosts natural acid rock drainage that significantly impacts surface water, streambed sediment, and aquatic life. The source of the ARD is a group of iron-rich springs that emerge from intensely hydrothermally altered, unexploited, low-grade porphyry copper mineralization in the Grizzly Peak Caldera. Source water chemistry includes pH of 2.5 and dissolved metal concentrations of up to 277 mg/L aluminum, 498 mg/L iron, and 10 mg/L copper. From the hydrothermally altered area downstream for 27 kilometers to Twin Lakes Reservoir, metal concentrations in streambed sediment are elevated and the watershed experiences locally severe adverse impacts to aquatic life due to the acidic, metal-laden water. The water and sediment quality of Twin Lakes Reservoir is sufficiently improved that the reservoir supports a trout fishery, and remnants of upstream ARD are negligible.

  9. Selective Removal of Lanthanides from Natural Waters, Acidic Streams and Dialysate

    SciTech Connect

    Yantasee, Wassana; Fryxell, Glen E.; Addleman, Raymond S.; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

    2009-09-15

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, increasing public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd, Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS®) that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (ProPhos), and 1-hydroxy-2-pyridinone (1,2-HOPO) from natural waters (river, ground, and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate and compares their performance to a high surface area activated carbon. The properties include sorption affinity, capacity, and sorption kinetics. Stability and regenerability of SAMMS materials were also investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. While the activated carbon is as effective as 1,2-HOPO-SAMMS for capturing lanthanides in natural (alkaline) waters, it has no affinity in acid solutions (pH 2.4) and low affinity in carbonate-rich dialysate. Over 99% of 100 ug/L of Gd in dialysate was removed by the ProPhos-SAMMS after ten minutes. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties, for a number of regeneration cycles. In acid solutions, PhoPhos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their potential for chromatographic lanthanide separations. Thus, SAMMS materials have a great potential to be used as sorbents in large scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and sorbent dialyzers for lanthanide clearances.

  10. To assess of behavior of natural colloid (soil extraction and fractionation of natural water) humus acid in comparison with synthetic humus acid

    NASA Astrophysics Data System (ADS)

    Dinu, Marina; Shkinev, Valery

    2015-04-01

    To study and predict the fate of natural colloid - nanoparticles in surface water or soil extraction - necessary to understand the features of the migration and physic-chemical activity of biocolloids. Comparison of the behavior of natural biocolloids, such as humus acid extracts of soil or natural water with artificial, synthetic humic acids (introduced into the environment) allows you to explore the mechanism of formation and transformation biocolloids under the influence of a number of parameters. In this work, we studied these interactions in natural surface waters from lakes and soil (Russian Federation, Kola North and Western Siberia) which displaying contrast organic and inorganic compositions. During the study, researches identified zonal features influence on the qualitative and quantitative composition of colloids, their stability and chemical activity. A model approach was also followed with synthetic water of comparable composition in order to better understand the driving mechanisms. We investigated the size, zeta potential and other physical and chemical parameters of the system. Particular attention is given to the process of complexation with heavy metal ions. As humic substances have excellent complexion properties and reduce the toxicity of many metal ions. The study of such non-static natural systems allow studying the features of the existence of natural colloidal components. The use of synthetic humic substances, which were introduced into the natural environment possible to study the standard mechanisms of formation, development and destruction of colloidal polymer systems. The obtained results allowed with used computer programs MatnLab, MathCad, Statistics simulate the processes of formation, development and functioning of natural colloids.

  11. Selective removal of lanthanides from natural waters, acidic streams and dialysate

    PubMed Central

    Yantasee, Wassana; Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

    2009-01-01

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS™), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 µg/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning. PMID:19345006

  12. Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific.

    PubMed

    Silver, Mary W; Bargu, Sibel; Coale, Susan L; Benitez-Nelson, Claudia R; Garcia, Ana C; Roberts, Kathryn J; Sekula-Wood, Emily; Bruland, Kenneth W; Coale, Kenneth H

    2010-11-30

    Near-surface waters ranging from the Pacific subarctic (58°N) to the Southern Ocean (66°S) contain the neurotoxin domoic acid (DA), associated with the diatom Pseudo-nitzschia. Of the 35 stations sampled, including ones from historic iron fertilization experiments (SOFeX, IronEx II), we found Pseudo-nitzschia at 34 stations and DA measurable at 14 of the 26 stations analyzed for DA. Toxin ranged from 0.3 fg·cell(-1) to 2 pg·cell(-1), comparable with levels found in similar-sized cells from coastal waters. In the western subarctic, descent of intact Pseudo-nitzschia likely delivered significant amounts of toxin (up to 4 μg of DA·m(-2)·d(-1)) to underlying mesopelagic waters (150-500 m). By reexamining phytoplankton samples from SOFeX and IronEx II, we found substantial amounts of DA associated with Pseudo-nitzschia. Indeed, at SOFeX in the Antarctic Pacific, DA reached 220 ng·L(-1), levels at which animal mortalities have occurred on continental shelves. Iron ocean fertilization also occurs naturally and may have promoted blooms of these ubiquitous algae over previous glacial cycles during deposition of iron-rich aerosols. Thus, the neurotoxin DA occurs both in coastal and oceanic waters, and its concentration, associated with changes in Pseudo-nitzschia abundance, likely varies naturally with climate cycles, as well as with artificial iron fertilization. Given that iron fertilization in iron-depleted regions of the sea has been proposed to enhance phytoplankton growth and, thereby, both reduce atmospheric CO(2) and moderate ocean acidification in surface waters, consideration of the potentially serious ecosystem impacts associated with DA is prudent. PMID:21068374

  13. Determination of phosphate in natural waters by activation analysis of tungstophosphoric acid

    USGS Publications Warehouse

    Allen, Herbert E.; Hahn, Richard B.

    1969-01-01

    Activation analysis may be used to determine quantitatively traces of phosphate in natural waters. Methods based on the reaction 31P(n,γ)32P are subject to interference by sulfur and chlorine which give rise to 32P through n,p and n,α reactions. If the ratio of phosphorus to sulfur or chlorine is small, as it is in most natural waters, accurate analyses by these methods are difficult to achieve. In the activation analysis method, molybdate and tungstate ions are added to samples containing phosphate ion to form tungstomolybdophosphoric acid. The complex is extracted with 2,6-dimethyl-4-heptanone. After activation of an aliquot of the organic phase for 1 hour at a flux of 1013 neutrons per cm2, per second, the gamma spectrum is essentially that of tungsten-187. The induced activity is proportional to the concentration of phosphate in the sample. A test of the method showed it to give accurate results at concentrations of 4 to at least 200 p.p.b. of phosphorus when an aliquot of 100 μl. was activated. By suitable reagent purification, counting for longer times, and activation of larger aliquots, the detection limit could be lowered several hundredfold.

  14. A practical application of Driscoll's equation for predicting the acid-neutralizing capacity in acidic natural waters equilibria with the mineral phase gibbsite.

    PubMed

    Bi, S P; An, S Q; Liu, F

    2001-05-01

    A practical application of Driscoll's equation for predicting the acid-neutralizing capacity (ANC) in acidic waters equilibria with the mineral phase gibbsite is reported in this paper. Theoretical predication values of ANC are compared with the experimental data obtained from different literatures. The effect of aluminum (Al) on the value of ANC is investigated. It indicates that Al plays an important role in regulating the buffering effects in acidic natural waters. Failure to consider Al in acidic waters may bias assessment results in certain situations so as to overestimate the ANC values in response to increase in atmospheric deposition.

  15. Concentration and fractionation of hydrophobic organic acid constituents from natural waters by liquid chromatography

    USGS Publications Warehouse

    Thurman, E.M.; Malcolm, R.L.

    1979-01-01

    A scheme is presented which used adsorption chromatography with pH gradient elution and size-exclusion chromatography to concentrate and separate hydrophobic organic acids from water. A review of chromatographic processes involved in the flow scheme is also presented. Organic analytes which appear in each aqueous fraction are quantified by dissolved organic carbon analysis. Hydrophobic organic acids in a water sample are concentrated on a porous acrylic resin. These acids usually constitute approximately 30-50 percent of the dissolved organic carbon in an unpolluted water sample and are eluted with an aqueous eluent (dilute base). The concentrate is then passed through a column of polyacryloylmorpholine gel, which separates the acids into high- and low-molecular-weight fractions. The high- and low-molecular-weight eluates are reconcentrated by adsorption chromatography, then are eluted with a pH gradient into strong acids (predominately carboxylic acids) and weak acids (predominately phenolic compounds). For standard compounds and samples of unpolluted waters, the scheme fractionates humic substances into strong and weak acid fractions that are separated from the low molecular weight acids. A new method utilizing conductivity is also presented to estimate the acidic components in the methanol fraction.

  16. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids

    NASA Astrophysics Data System (ADS)

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-08-01

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

  17. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids.

    PubMed

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-08-16

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

  18. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids

    PubMed Central

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-01-01

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes. PMID:27526869

  19. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids.

    PubMed

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-01-01

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes. PMID:27526869

  20. Precipitation: its acidic nature.

    PubMed

    Frohliger, J O; Kane, R

    1975-08-01

    A comparison of the free hydrogen ion concentration and the total hydrogen ion concentration of rain samples shows that rain is a weak acid. The weak acid nature of rain casts doubt on the concepts that the acidity of rain is increasing and that these increases are due to strong acids such as sulfuric acid.

  1. Evolution of water chemistry in natural acidic environments in Yangmingshan, Taiwan.

    PubMed

    Ezoe, Yuka; Lin, Cheng-Huang; Noto, Masami; Watanabe, Yoshihiro; Yoshimura, Kazuhisa

    2002-08-01

    In Yangmingshan National Park, located in the northern part of the Taiwan Island, there is a very rare area where fish (Channa asiatica) live in spite of acid environments. The origin of the acid in local acid ponds and rivers and the evolution of the water chemistry are discussed on the basis of sulfur stable isotope ratios and chemical equilibria. One of the sources of the acid is sulfuric acid, which is derived from the oxidation of hydrogen sulfide in volcanic gas gushing out from fumaroles around the area and from acid deposition supplied from Taipei City. It is also derived from the oxidation of pyrite: the sulfur stable isotope ratios of delta 34S of +1@1000 to +4@1000 (relative to CDT) of sulfate in acid pond waters (pH 3-4) could be related to those of hydrogen sulfide in volcanic gas, pyrite in local pond sediments and soils, and sulfate in rain water. One acid source is sulfuric and hydrochloric acids arising in springs from geothermal activity: the delta 34S values were characterised by +13@1000 to +17@1000 sulfate-S, which was provided by a disproportionation reaction of sulfur dioxide in the depths. Another acid source could be the oxidation of iron(II). Under acidic conditions, the water-rock reaction gives rise to high concentrations of aluminium and iron. While flowing down surface streams, iron(II) is oxidised to iron(III) and then hydrolysed to cause further acidification under oxic conditions. The concentrations of iron and aluminium are controlled by redox and dissolution equilibria.

  2. Cold water fish gelatin modification by a natural phenolic cross-linker (ferulic acid and caffeic acid)

    PubMed Central

    Araghi, Maryam; Moslehi, Zeinab; Mohammadi Nafchi, Abdorreza; Mostahsan, Amir; Salamat, Nima; Daraei Garmakhany, Amir

    2015-01-01

    Nowadays use of edible films and coatings is increasing due to their biodegradability and environment friendly properties. Fish gelatin obtained from fish skin wastage can be used as an appropriate protein compound for replacing pork gelatin to produce edible film. In this study films were prepared by combination of fish gelatin and different concentration (0%, 1%, 3%, and 5%) of two phenolic compounds (caffeic acid and ferulic acid). The film was prepared at pH > 10 and temperature of 60˚c under continuous injection of O2 and addition of the plasticizer sorbitol/glycerol. Results showed that solubility, oxygen permeability, and water vapor permeability were decreased for caffeic acid and the highest effect was observed at concentration of 5%. Solubility had a linear relationship with concentration of phenolic compound in film containing ferulic acid, however, no significant change was observed in vapor and O2 permeability. A comparison between two phenolic compounds showed that caffeic acid had the highest effect in decreasing solubility, water vapor permeability, and oxygen permeability. Caffeic acid is more effective phenolic compound compared with Ferulic acid that can increase safety of biodegradable packaging by improving their barrier and physicochemical properties. PMID:26405523

  3. Acid generation upon thermal concentration of natural water: The critical water content and the effects of ionic composition

    NASA Astrophysics Data System (ADS)

    Pulvirenti, April L.; Needham, Karen M.; Adel-Hadadi, Mohamad A.; Marks, Charles R.; Gorman, Jeffrey A.; Shettel, Donald L.; Barkatt, Aaron

    2009-10-01

    Thermal evaporation of a variety of simulated pore waters from the region of Yucca Mountain, Nevada, produced acidic liquids and gases during the final stages of evaporation. Several simulated pore waters were prepared and then thermally distilled in order to collect and analyze fractions of the evolved vapor. In some cases, distillates collected towards the end of the distillation were highly acidic; in other cases the pH of the distillate remained comparatively unchanged during the course of the distillation. The results suggest that the pH values of the later fractions are determined by the initial composition of the water. Acid production stems from the hydrolysis of magnesium ions, especially at near dryness. Near the end of the distillation, magnesium nitrate and magnesium chloride begin to lose water of hydration, greatly accelerating their thermal decomposition to form acid. Acid formation is promoted further when precipitated calcium carbonate is removed. Specifically, calcium chloride-rich pore waters containing moderate (10-20 ppm) levels of magnesium and nitrate and low levels of bicarbonate produced mixtures of nitric and hydrochloric acid, resulting in a precipitous drop in pH to values of 1 or lower after about 95% of the original volume was distilled. Waters with either low or moderate magnesium content coupled with high levels of bicarbonate produced slightly basic fractions (pH 7-9). If calcium was present in excess of bicarbonate, waters containing moderate levels of magnesium produced acid even in the presence of bicarbonate, due to the precipitation of calcium carbonate. Other salts such as halite and anhydrite promote the segregation of acidic vapors from residual basic solids. The concomitant release of wet acid gas has implications for the integrity of the alloys under consideration for containers at the Yucca Mountain nuclear waste repository. Condensed acid gases at very low pH, especially mixtures of nitric and hydrochloric acid, are

  4. Acid generation upon thermal concentration of natural water: the critical water content and the effects of ionic composition.

    PubMed

    Pulvirenti, April L; Needham, Karen M; Adel-Hadadi, Mohamad A; Marks, Charles R; Gorman, Jeffrey A; Shettel, Donald L; Barkatt, Aaron

    2009-10-13

    Thermal evaporation of a variety of simulated pore waters from the region of Yucca Mountain, Nevada, produced acidic liquids and gases during the final stages of evaporation. Several simulated pore waters were prepared and then thermally distilled in order to collect and analyze fractions of the evolved vapor. In some cases, distillates collected towards the end of the distillation were highly acidic; in other cases the pH of the distillate remained comparatively unchanged during the course of the distillation. The results suggest that the pH values of the later fractions are determined by the initial composition of the water. Acid production stems from the hydrolysis of magnesium ions, especially at near dryness. Near the end of the distillation, magnesium nitrate and magnesium chloride begin to lose water of hydration, greatly accelerating their thermal decomposition to form acid. Acid formation is promoted further when precipitated calcium carbonate is removed. Specifically, calcium chloride-rich pore waters containing moderate (10-20 ppm) levels of magnesium and nitrate and low levels of bicarbonate produced mixtures of nitric and hydrochloric acid, resulting in a precipitous drop in pH to values of 1 or lower after about 95% of the original volume was distilled. Waters with either low or moderate magnesium content coupled with high levels of bicarbonate produced slightly basic fractions (pH 7-9). If calcium was present in excess of bicarbonate, waters containing moderate levels of magnesium produced acid even in the presence of bicarbonate, due to the precipitation of calcium carbonate. Other salts such as halite and anhydrite promote the segregation of acidic vapors from residual basic solids. The concomitant release of wet acid gas has implications for the integrity of the alloys under consideration for containers at the Yucca Mountain nuclear waste repository. Condensed acid gases at very low pH, especially mixtures of nitric and hydrochloric acid, are

  5. Natural attenuation processes in two water reservoirs receiving acid mine drainage.

    PubMed

    Sarmiento, Aguasanta M; Olías, Manuel; Nieto, José Miguel; Cánovas, Carlos R; Delgado, Joquín

    2009-03-01

    Characteristics of water profiles and sulphide formation processes in sediments were studied in two water reservoirs affected by acid mine drainage in order to investigate the mechanisms controlling the physical and chemical processes that, under favourable conditions, act to reduce the toxicity, mobility and concentration of metals and metalloids in the water column. Water columns and pore-waters from sediments were analysed for Fe species, trace elements (As, Cd, Co, Cu, Mn, Ni, Pb, Zn, Cr), sulphide, sulphate and bicarbonate. Inorganic reduced sulphur compounds (acid volatile sulphur, pyrite sulphur and elemental sulphur) and reactive Fe were determined in the sediments. A sequential extraction was also performed. Both reservoirs behave like holomictic and monomictic lakes, with a summer thermal stratification that disappears during winter. pH values between 4 and 7 can be observed along the water columns. Pore-water concentrations of up to 25 mg/l of Fe, 4 mg/l of Al, 1.3 mg/l of Zn, 170 microg/l of Pb, 11 microg/l of As, etc. have been found. The results suggest that toxic elements such as Cu, Zn, Co, Pb, Cr, As, etc. are mainly found in the bioavailable fraction which is the most hazardous for the environment. The calculated degree of sulphidization (DOS) and degree of pyritization (DOP) values indicates that removal of trace elements from anoxic pore-waters occurs by coprecipitation and/or adsorption on newly formed Fe sulphides (framboidal pyrite), attenuating the contamination. However oxidation of the sediments during turnover periods also occurs, which releases toxic elements back into the water column. PMID:19073338

  6. Seasonal variation of fatty acid content in natural microplankton from the Tumpat coastal waters of the South China Sea.

    PubMed

    Shamsudin, L

    1998-07-01

    In the search for better understanding on the nutritional quality of natural tropical plankton, samples were collected from shallow coastal waters facing the South China Sea during the dry monsoon (May-September) and the wet monsoon (November-April) seasons from March 1993 to July 1994. The total fatty acid content of the predominantly phytoplankton communities (25-200 microns sieve nets) varied four to fivefold with the lowest value occurring during the dry monsoon when blue-green became predominant. Saturated fatty acid content (SAFA), polyunsaturated fatty acid (PUFA) and total omega 3 (sigma omega 3) showed the same seasonal pattern as the total fatty acid with high values in October to December 1993. When species of the dinoflagellate Peridinium and Ceratium were present in considerable amount, the docosahexaenoic acid DHA content was high, especially from March to May 1993. The maximum content of eicosapentaenoic acid EPA, total omega-3 fatty acid, PUFA and sigma omega 3 in phytoplankton occurred during the pre-monsoon period (October and November 1993) when the diatoms were present in large amounts. The larger fraction sample (> 200 microns sieve nets) which consisted predominantly of zooplankton had high amounts of PUFA from September to November 1993. PMID:10099722

  7. Seasonal variation of fatty acid content in natural microplankton from the Tumpat coastal waters of the South China Sea.

    PubMed

    Shamsudin, L

    1998-07-01

    In the search for better understanding on the nutritional quality of natural tropical plankton, samples were collected from shallow coastal waters facing the South China Sea during the dry monsoon (May-September) and the wet monsoon (November-April) seasons from March 1993 to July 1994. The total fatty acid content of the predominantly phytoplankton communities (25-200 microns sieve nets) varied four to fivefold with the lowest value occurring during the dry monsoon when blue-green became predominant. Saturated fatty acid content (SAFA), polyunsaturated fatty acid (PUFA) and total omega 3 (sigma omega 3) showed the same seasonal pattern as the total fatty acid with high values in October to December 1993. When species of the dinoflagellate Peridinium and Ceratium were present in considerable amount, the docosahexaenoic acid DHA content was high, especially from March to May 1993. The maximum content of eicosapentaenoic acid EPA, total omega-3 fatty acid, PUFA and sigma omega 3 in phytoplankton occurred during the pre-monsoon period (October and November 1993) when the diatoms were present in large amounts. The larger fraction sample (> 200 microns sieve nets) which consisted predominantly of zooplankton had high amounts of PUFA from September to November 1993.

  8. Ion-exchange chromatography of mono- and divalent cations in natural waters on a weak-acid anion-exclusion column.

    PubMed

    Tanaka, K; Ohta, K; Haddad, P R; Fritz, J S

    1998-04-24

    Ion-exchange chromatography with indirect conductimetric detection for the simultaneous determination of mono- and divalent cations is investigated using an anion-exclusion chromatographic column packed with polymethacrylate-based weakly acidic cation-exchange resin in the H+ form (Tosoh TSKgel OA-PAK-A, 300 mm x 7.8 mm I.D.). An eluent comprising a strong acid, a weak organic acid, methanol and water is used. Using 0.75 mM sulfuric acid, 2 mM tartaric acid, 7.5% (v/v) methanol in water as eluent, the monovalent cations (Na+, NH4+, and K+) and divalent cations (Mg2+ and Ca2+) were separated simultaneously by a cation-exchange mechanism in about 25 min. The application of this method to the analysis of several natural waters including rain, river, lake, underground and forest soil waters for estimating acid rain effects on the natural and urban environments is presented.

  9. Helix-coil stability constants for the naturally occurring amino acids in water. IX. Glutamic acid parameters from random poly(hydroxybutylglutamine-co-L-glutamic acid).

    PubMed

    Maxfield, F R; Alter, J E; Taylor, G T; Scheraga, H A

    1975-01-01

    The synthesis and characterization of water-soluble random copolymers containing L-glutamic acid with N5-(4-hydroxybutyl)-L-glutamine and the thermally induced helix-coil transitions of these copolymers in water and in 0.1 N KCl are described. The incorporation of L-glutamic acid was found to increase the helix content of the polymer at low pH and to decrease it at high pH even though the presence of 0.1 N KCl effectively eliminated the difference between the electrostatic free energies of the helix and the coil. The Zimm-Bragg parameters sigma and s for the helix-coil transition in poly(L-glutamic acid) in water and in 0.1 N KCl were deduced from an analysis of the melting curves of the copolymers in the manner described in earlier papers. The synthesis of N-acetyl-N'-methylglutamic acid amide and its titration, as well as that of the copolymers and poly(L-glutamic acid), in 0.1 N KCl are described.

  10. Distribution of aquatic animals relative to naturally acidic waters in the Sierra Nevada. Final report

    SciTech Connect

    Bradford, D.F.; Cooper, S.D.; Brown, A.D.; Mahood, G.

    1994-01-01

    Lakes in the Bench Lake/Mount Pinchot area of Kings Canyon National Park were surveyed in summer 1992 and found to range in pH from 5.0 to 9.3. Ten lakes were acidic (pH < 6.0). Thirty three lakes were chosen for detailed analyses of their chemical and biological characteristics, including eight acidic lakes. Unlike typical Ca-Na-HCO3-dominated Sierra lakes, SO4 concentrations are high enough to classify 19 of these lakes with SO4 as the dominant anion. The source of acidity and SO4 is sulfuric acid produced by the oxidation of pyrite found in metamorphic and granitic rocks in the area. Faunal surveys revealed that yellow-legged frog tadpoles (Rana muscosa), limnephilid caddis larvae (Hesperophylax), and large microcrustaceans (Daphnia, Diaptomus) were rare or absent in acidic lakes and common in lakes with a pH > 6.0. Four species of trout were collected, and their presence appeared to be related to historical stocking patterns. Trout appeared to have large effects on the distributions and abundances of larval amphibians and large, mobile invertebrate taxa that were rare or absent in trout lakes, but common in lakes lacking trout.

  11. Defensive strategies in Geranium sylvaticum, Part 2: Roles of water-soluble tannins, flavonoids and phenolic acids against natural enemies.

    PubMed

    Tuominen, Anu

    2013-11-01

    Geranium sylvaticum is a common herbaceous plant in Fennoscandia, which has a unique phenolic composition. Ellagitannins, proanthocyanidins, galloylglucoses, gallotannins, galloyl quinic acids and flavonoids possess variable distribution in its different organs. These phenolic compounds are thought to have an important role in plant-herbivore interactions. The aim of this study was to quantify these different water-soluble phenolic compounds and measure the biological activity of the eight organs of G. sylvaticum. Compounds were characterized and quantified using HPLC-DAD/MS, in addition, total proanthocyanidins were determined by BuOH-HCl assay and total phenolics by the Folin-Ciocalteau method. Two in vitro biological activity measurements were used: the prooxidant activity was measured by the browning assay and antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Organ extracts were fractionated using column chromatography on Sephadex LH-20 and the activities of fractions was similarly measured to evaluate which polyphenol groups contributed the most to the biological activity of each organ. The data on the activity of fractions were examined by multivariate data analysis. The water-soluble extracts of leaves and pistils, which contained over 30% of the dry weight as ellagitannins, showed the highest pro-oxidant activity among the organ extracts. Fraction analysis revealed that flavonoids and galloyl quinic acids also exhibited high pro-oxidant activity. In contrast, the most antioxidant active organ extracts were those of the main roots and hairy roots that contained high amounts of proanthocyanidins in addition to ellagitannins. Analysis of the fractions showed that especially ellagitannins and galloyl quinic acids have high antioxidant activity. We conclude that G. sylvaticum allocates a significant amount of tannins in those plant parts that are important to the fitness of the plant and susceptible to natural enemies, i

  12. The contribution of humic substances to the acidity of colored natural waters

    USGS Publications Warehouse

    Oliver, B.G.; Thurman, E.M.; Malcolm, R.L.

    1983-01-01

    An operationally defined carboxyl content of humic substances extracted from rivers, streams, lakes, wetlands, and groundwaters throughout the United States and Canada is reported. Despite the diversity of the samples, only small variations were observed in this humic carboxyl content. The dissociation behavior of two combined fulvic/humic acid extracts was studied and it was found that the dissociation of the humics varied in a predictable manner with pH. Using a carboxyl content of 10 ??eq/ mg humic organic carbon, and mass action quotient calculated from sample pH, the ionic balances of three highly colored Nova Scotia rivers were estimated. ?? 1983.

  13. The role of natural purified humic acids in modifying mercury accessibility in water and soil

    SciTech Connect

    Cattani, I.; Zhang, H.; Beone, G.M.; Del Re, A.A.M.; Boccelli, R.; Trevisan, M.

    2009-03-15

    We investigated the influence of different humic acids (HAs, extracted from lignite, compost, and forest soil) on mercury mobility and availability both in a model solution and in soil samples from a mercury-polluted region. The technique of diffusive gradients in thin-films (DGT), which is capable of measuring: (i) free metal in solution: (ii) dissociated metal complexes previously mobilized by HA; (iii) mobilized metal-HA complexes that liberate metals by dissociation or by exchange reaction between the metal-HA complexes and the chelating groups on the resin-gel, was used in solutions and soils. The DGT measurements in solution, together with ultrafiltration, allowed estimation of the lability of Hg-HA complexes. Ultrafiltration results were also compared with predictions made by the windermere humic-aqueous model (WHAM). According to both these different approaches, Hg{sup 2+} resulted nearly 100% complexed by HAs, whereas results from ultrafiltration showed that 32 to 72% of the CH{sub 4}Hg{sup +} was bound to the HAs, with higher values for compost and lower values for forest and Aldrich HA. The DGT-measured mercury in soils was below 0.20 {mu}g L{sup -1}, irrespective of the extent of the contamination. Addition of HA increased the concentration of DGT-measured mercury in soil solution up to 100-fold in the contaminated soil and up to 30-fold in the control soil. The level of the increase also depended on the HA. The smallest increase (about 10 times) was found for lignite HA in both control and contaminated soils. The addition of forest HA gave the largest increases in DGT-measured mercury, in particular for the contaminated soil. Overall, the results demonstrated that DGT can be used for estimating the lability of mercury complexes in solution and for verifying enhanced mercury mobility when HA is added to contaminated soils.

  14. Stability of uncoated and fulvic acids coated manufactured CeO2 nanoparticles in various conditions: From ultrapure to natural Lake Geneva waters.

    PubMed

    Oriekhova, Olena; Stoll, Serge

    2016-08-15

    Understanding the behavior of engineered nanoparticles in natural water and impact of water composition in changing conditions is of high importance to predict their fate once released into the environment. In this study we investigated the stability of uncoated and Suwannee River fulvic acids coated CeO2 manufactured nanoparticles in various environmental conditions. The effect of pH changes on the nanoparticle and coating stability was first studied in ultrapure water as well as the variation of zeta potentials and sizes with time in presence of fulvic acids at environmental pH. Then the stability of CeO2 in synthetic and natural Lake Geneva waters was investigated as a function of fulvic acids concentration. Our results indicate that the adsorption of environmentally relevant concentrations of Suwannee River fulvic acids promotes CeO2 stabilization in ultrapure water as well as synthetic water and that the coating stability is high upon pH variations. On the other hand in natural Lake Geneva water CeO2 NPs are found in all cases aggregated due to the effect of heterogeneous organic and inorganic compounds.

  15. Identification of Novel Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs) in Natural Waters Using Accurate Mass Time-of-Flight Mass Spectrometry (TOFMS).

    PubMed

    Strynar, Mark; Dagnino, Sonia; McMahen, Rebecca; Liang, Shuang; Lindstrom, Andrew; Andersen, Erik; McMillan, Larry; Thurman, Michael; Ferrer, Imma; Ball, Carol

    2015-10-01

    Recent scientific scrutiny and concerns over exposure, toxicity, and risk have led to international regulatory efforts resulting in the reduction or elimination of certain perfluorinated compounds from various products and waste streams. Some manufacturers have started producing shorter chain per- and polyfluorinated compounds to try to reduce the potential for bioaccumulation in humans and wildlife. Some of these new compounds contain central ether oxygens or other minor modifications of traditional perfluorinated structures. At present, there has been very limited information published on these "replacement chemistries" in the peer-reviewed literature. In this study we used a time-of-flight mass spectrometry detector (LC-ESI-TOFMS) to identify fluorinated compounds in natural waters collected from locations with historical perfluorinated compound contamination. Our workflow for discovery of chemicals included sequential sampling of surface water for identification of potential sources, nontargeted TOFMS analysis, molecular feature extraction (MFE) of samples, and evaluation of features unique to the sample with source inputs. Specifically, compounds were tentatively identified by (1) accurate mass determination of parent and/or related adducts and fragments from in-source collision-induced dissociation (CID), (2) in-depth evaluation of in-source adducts formed during analysis, and (3) confirmation with authentic standards when available. We observed groups of compounds in homologous series that differed by multiples of CF2 (m/z 49.9968) or CF2O (m/z 65.9917). Compounds in each series were chromatographically separated and had comparable fragments and adducts produced during analysis. We detected 12 novel perfluoroalkyl ether carboxylic and sulfonic acids in surface water in North Carolina, USA using this approach. A key piece of evidence was the discovery of accurate mass in-source n-mer formation (H(+) and Na(+)) differing by m/z 21.9819, corresponding to the

  16. Naturally acidic surface and ground waters draining porphyry-related mineralized areas of the Southern Rocky Mountains, Colorado and New Mexico

    USGS Publications Warehouse

    Verplanck, P.L.; Nordstrom, D.K.; Bove, D.J.; Plumlee, G.S.; Runkel, R.L.

    2009-01-01

    Acidic, metal-rich waters produced by the oxidative weathering and resulting leaching of major and trace elements from pyritic rocks can adversely affect water quality in receiving streams and riparian ecosystems. Five study areas in the southern Rocky Mountains with naturally acidic waters associated with porphyry mineralization were studied to document variations in water chemistry and processes that control the chemical variations. Study areas include the Upper Animas River watershed, East Alpine Gulch, Mount Emmons, and Handcart Gulch in Colorado and the Red River in New Mexico. Although host-rock lithologies in all these areas range from Precambrian gneisses to Cretaceous sedimentary units to Tertiary volcanic complexes, the mineralization is Tertiary in age and associated with intermediate to felsic composition, porphyritic plutons. Pyrite is ubiquitous, ranging from ???1 to >5 vol.%. Springs and headwater streams have pH values as low as 2.6, SO4 up to 3700 mg/L and high dissolved metal concentrations (for example: Fe up to 400 mg/L; Cu up to 3.5 mg/L; and Zn up to 14.4 mg/L). Intensity of hydrothermal alteration and presence of sulfides are the primary controls of water chemistry of these naturally acidic waters. Subbasins underlain by intensely hydrothermally altered lithologies are poorly vegetated and quite susceptible to storm-induced surface runoff. Within the Red River study area, results from a storm runoff study documented downstream changes in river chemistry: pH decreased from 7.80 to 4.83, alkalinity decreased from 49.4 to <1 mg/L, SO4 increased from 162 to 314 mg/L, dissolved Fe increased from to 0.011 to 0.596 mg/L, and dissolved Zn increased from 0.056 to 0.607 mg/L. Compared to mine drainage in the same study areas, the chemistry of naturally acidic waters tends to overlap but not reach the extreme concentrations of metals and acidity as some mine waters. The chemistry of waters draining these mineralized but unmined areas can be used to

  17. Discovery of Cyanuric Acid During an Assessment of Natural Organic Matter in Stormflow Water of the Santa Ana River, Southern California, 2003-2004

    USGS Publications Warehouse

    Leenheer, Jerry A.; Izbicki, John A.; Rostad, Colleen E.; Noyes, Ted I.; Woodside, Greg

    2007-01-01

    A stormflow study of natural organic matter and organic contaminants in the Santa Ana River, the Mill Creek tributary, and an urban drain tributary discovered cyanuric acid in variable concentrations up to 510 ?g/L. Cyanuric acid was isolated with a hydrophilic natural organic matter (NOM) fraction, and its identity was confirmed by a combination of infrared spectrometry, 13C-nuclear magnetic resonance (13C-NMR) spectrometry, and electrospray ionization/mass spectrometry. Cyanuric acid concentrations, based upon 13C-NMR spectral quantitation, increased during the peak and recessional flows of the storm hydrographs during three storms at three sites. The greatest fluxes of cyanuric acid were observed in the Santa Ana River during the third storm. The most likely source of cyanuric acid is as a metabolite of triazine herbicides, based on hydrographs, land uses of the drainage basins, and the yearly application rates of triazine herbicides. The daily flux of cyanuric acid in Santa Ana River stormflow during the third storm was calculated to be about 1 percent of the yearly application rate for triazine herbicides. Cyanuric acid was not detected in ground water at wells adjacent to the Santa Ana River.

  18. Application of natural citric acid sources and their role on arsenic removal from drinking water: a green chemistry approach.

    PubMed

    Majumder, Santanu; Nath, Bibhash; Sarkar, Simita; Islam, Sk Mijanul; Bundschuh, Jochen; Chatterjee, Debashis; Hidalgo, Manuela

    2013-11-15

    Solar Oxidation and Removal of Arsenic (SORAS) is a low-cost non-hazardous technique for the removal of arsenic (As) from groundwater. In this study, we tested the efficiency of natural citric acid sources extracted from tomato, lemon and lime to promote SORAS for As removal at the household level. The experiment was conducted in the laboratory using both synthetic solutions and natural groundwater samples collected from As-polluted areas in West Bengal. The role of As/Fe molar ratios and citrate doses on As removal efficiency were checked in synthetic samples. The results demonstrate that tomato juice (as citric acid) was more efficient to remove As from both synthetic (percentage of removal: 78-98%) and natural groundwater (90-97%) samples compared to lemon (61-83% and 79-85%, respectively) and lime (39-69% and 63-70%, respectively) juices. The As/Fe molar ratio and the citrate dose showed an 'optimized central tendency' on As removal. Anti-oxidants, e.g. 'hydroxycinnamates', found in tomato, were shown to have a higher capacity to catalyze SORAS photochemical reactions compared to 'flavanones' found in lemon or lime. The application of this method has several advantages, such as eco- and user- friendliness and affordability at the household level compared to other low-cost techniques. PMID:23122734

  19. Application of natural citric acid sources and their role on arsenic removal from drinking water: a green chemistry approach.

    PubMed

    Majumder, Santanu; Nath, Bibhash; Sarkar, Simita; Islam, Sk Mijanul; Bundschuh, Jochen; Chatterjee, Debashis; Hidalgo, Manuela

    2013-11-15

    Solar Oxidation and Removal of Arsenic (SORAS) is a low-cost non-hazardous technique for the removal of arsenic (As) from groundwater. In this study, we tested the efficiency of natural citric acid sources extracted from tomato, lemon and lime to promote SORAS for As removal at the household level. The experiment was conducted in the laboratory using both synthetic solutions and natural groundwater samples collected from As-polluted areas in West Bengal. The role of As/Fe molar ratios and citrate doses on As removal efficiency were checked in synthetic samples. The results demonstrate that tomato juice (as citric acid) was more efficient to remove As from both synthetic (percentage of removal: 78-98%) and natural groundwater (90-97%) samples compared to lemon (61-83% and 79-85%, respectively) and lime (39-69% and 63-70%, respectively) juices. The As/Fe molar ratio and the citrate dose showed an 'optimized central tendency' on As removal. Anti-oxidants, e.g. 'hydroxycinnamates', found in tomato, were shown to have a higher capacity to catalyze SORAS photochemical reactions compared to 'flavanones' found in lemon or lime. The application of this method has several advantages, such as eco- and user- friendliness and affordability at the household level compared to other low-cost techniques.

  20. Analysis and detection of the herbicides dimethenamid and flufenacet and their sulfonic and oxanilic acid degradates in natural water

    USGS Publications Warehouse

    Zimmerman, L.R.; Schneider, R.J.; Thurman, E.M.

    2002-01-01

    Dimethenamid [2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide] and flufenacet [N-(4-fluorophenyl)-N-(1-methylethyl)-2-(5-(trifluoromethyl)-1,3,4- thiadiazol-2-yl)oxy] were isolated by C-18 solid-phase extraction and separated from their ethanesulfonic acid (ESA) and oxanilic acid (OXA) degradates during their elution using ethyl acetate for the parent compound, followed by methanol for the polar degradates. The parent compounds were detected using gas chromatography-mass spectrometry in selected-ion mode. The ESA and OXA degradates were detected using high-performance liquid chromatography-electrospray mass spectrometry (HPLC-ESPMS) in negative-ion mode. The method detection limits for a 123-mL sample ranged from 0.01 to 0.07 ??g/L. These methods are compatible with existing methods and thus allow for analysis of 17 commonly used herbicides and 18 of their degradation compounds with one extraction. In a study of herbicide transport near the mouth of the Mississippi River during 1999 and 2000, dimethenamid and its ESA and OXA degradates were detected in surface water samples during the annual spring flushes. For flufenacet, the only detections at the study site were for the ESA degradates in samples collected at the peak of the herbicide spring flush in 2000. The low frequency of detections in surface water likely is due to dimethenamid and flufenacet being relatively new herbicides. In addition, detectable amounts of the stable degradates have not been detected in ground water.

  1. Decreased toxicity of Al to juvenile Atlantic salmon (Salmo salar) in acidic soft water containing natural organic matter: A test of the free-ion model

    SciTech Connect

    Roy, R.L.; Campbell, P.G.C.

    1997-09-01

    Toxicological experiments were designed to test the predictions of the free-ion model (FIM) in a soft, acidic water containing Al and a natural fulvic acid (FA). Juvenile Atlantic salmon (Salmo salar) were exposed to Al in either inorganic or organic acidic soft waters, at pH 5.0, and 50% lethal concentrations (LC50) values were determined for both exposure solutions. Contrary to the predictions of the FIM, the LC50s, expressed as inorganic Al (Al{sub i}), were significantly higher in the organic solution than in the inorganic medium. Preexposure of the fish to a 10-mg/L FA solution at pH 5.0, without Al, did not protect the animals from a subsequent Al challenge in solutions without FA. A regression model related mortality with Al{sub i} and total organic carbon (TOC) and was highly significant. The authors conclude that natural FA may play an independent protective role in solutions containing Al, in addition to that of decreasing Al toxicity by complexation of the metal and reducing the free Al{sup 3+} concentration.

  2. Effects of natural water ions and humic acid on catalytic nitrate reduction kinetics using an alumina supported Pd-Cu catalyst.

    PubMed

    Chaplin, Brian P; Roundy, Eric; Guy, Kathryn A; Shapley, John R; Werth, Charles J

    2006-05-01

    Catalytic nitrate reduction was evaluated for the purpose of drinking water treatment. Common anions present in natural waters and humic acid were evaluated for their effects on NO3(-) hydrogenation over a bimetallic supported catalyst (Pd-Cu/gamma-Al2O3). Groundwater samples, with and without powder activated carbon (PAC) pretreatment, were also evaluated. In the absence of inhibitors the NO3- reduction rate was 2.4 x 10(-01) L/min g cat. However, the addition of constituents (SO4(2-), SO3(2-), HS-, CI-, HCO3-, OH-, and humic acid) on the order of representative concentrations for drinking water decreased the NO3- reduction rate. Sulfite, sulfide, and elevated chloride decreased the NO3- reduction rate by over 2 orders of magnitude. Preferential adsorption of Cl- inhibited NO3- reduction to a greater extent than NO2- reduction. Partial regeneration of catalysts exposed to SO3(2-) was achieved by using a dilute hypochlorite solution, however Cu dissolution occurred. Dissolved constituents in the groundwater sample decreased the NO3- reduction rate to 3.7 x 10(-03) L/min g cat and increased ammonia production. Removal of dissolved organic matter from the groundwater using PAC increased the NO3- reduction rate to 5.06 x 10(-02) L/min g cat and decreased ammonia production. Elemental analyses of catalysts exposed to the natural groundwater suggest that mineral precipitation may also contribute to catalyst fouling. PMID:16719114

  3. Grasses of different C4 subtypes reveal leaf traits related to drought tolerance in their natural habitats: Changes in structure, water potential, and amino acid content.

    PubMed

    Carmo-Silva, Ana E; Francisco, Ana; Powers, Stephen J; Keys, Alfred J; Ascensão, Lia; Parry, Martin A J; Arrabaça, Maria Celeste

    2009-07-01

    Three grasses (Poaceae) of different C(4) subtypes, Paspalum dilatatum (NADP-malic enzyme [ME]), Cynodon dactylon (NAD-ME) and Zoysia japonica (phosphoenolpyruvate carboxykinase), occur in natural habitats that differ in annual rainfall. Their leaf characteristics were studied to identify traits related to drought tolerance. Plants were grown in pots, and water deficit was gradually induced by withholding water. Leaves of Z. japonica had the greatest and P. dilatatum the lowest relative dry matter content. Transverse sections of leaves that developed during the water deficit showed little change compared to control leaves, consistent with low phenotypic plasticity. Anatomical features distinguished the three species, with xeromorphic characteristics most strongly represented in Z. japonica. The leaf relative water content (RWC) decreased with the soil water content similarly for the three grasses. However, at 80% RWC, the leaf water potential was -3.1 MPa for Z. japonica and only -1.3 MPa for P. dilatatum and C. dactylon. Soluble amino acids, especially proline, increased as RWC decreased in leaves of C. dactylon and Z. japonica. Phenylalanine, valine, leucine, and isoleucine increased more in Z. japonica than in the other two species. The results provide evidence that C. dactylon and, especially, Z. japonica have evolved leaf traits better suited to arid habitats.

  4. Beyond Naphthenic Acids: Environmental Screening of Water from Natural Sources and the Athabasca Oil Sands Industry Using Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    PubMed

    Barrow, Mark P; Peru, Kerry M; Fahlman, Brian; Hewitt, L Mark; Frank, Richard A; Headley, John V

    2015-09-01

    There is a growing need for environmental screening of natural waters in the Athabasca region of Alberta, Canada, particularly in the differentiation between anthropogenic and naturally-derived organic compounds associated with weathered bitumen deposits. Previous research has focused primarily upon characterization of naphthenic acids in water samples by negative-ion electrospray ionization methods. Atmospheric pressure photoionization is a much less widely used ionization method, but one that affords the possibility of observing low polarity compounds that cannot be readily observed by electrospray ionization. This study describes the first usage of atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (in both positive-ion and negative-ion modes) to characterize and compare extracts of oil sands process water, river water, and groundwater samples from areas associated with oil sands mining activities. When comparing mass spectra previously obtained by electrospray ionization and data acquired by atmospheric pressure photoionization, there can be a doubling of the number of components detected. In addition to polar compounds that have previously been observed, low-polarity, sulfur-containing compounds and hydrocarbons that do not incorporate a heteroatom were detected. These latter components, which are not amenable to electrospray ionization, have potential for screening efforts within monitoring programs of the oil sands.

  5. Beyond Naphthenic Acids: Environmental Screening of Water from Natural Sources and the Athabasca Oil Sands Industry Using Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    PubMed

    Barrow, Mark P; Peru, Kerry M; Fahlman, Brian; Hewitt, L Mark; Frank, Richard A; Headley, John V

    2015-09-01

    There is a growing need for environmental screening of natural waters in the Athabasca region of Alberta, Canada, particularly in the differentiation between anthropogenic and naturally-derived organic compounds associated with weathered bitumen deposits. Previous research has focused primarily upon characterization of naphthenic acids in water samples by negative-ion electrospray ionization methods. Atmospheric pressure photoionization is a much less widely used ionization method, but one that affords the possibility of observing low polarity compounds that cannot be readily observed by electrospray ionization. This study describes the first usage of atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (in both positive-ion and negative-ion modes) to characterize and compare extracts of oil sands process water, river water, and groundwater samples from areas associated with oil sands mining activities. When comparing mass spectra previously obtained by electrospray ionization and data acquired by atmospheric pressure photoionization, there can be a doubling of the number of components detected. In addition to polar compounds that have previously been observed, low-polarity, sulfur-containing compounds and hydrocarbons that do not incorporate a heteroatom were detected. These latter components, which are not amenable to electrospray ionization, have potential for screening efforts within monitoring programs of the oil sands. PMID:26115966

  6. Methylgermanium in natural waters

    NASA Astrophysics Data System (ADS)

    Lewis, Brent L.; Froelich, Philip N.; Andreae, Meinrat O.

    1985-01-01

    Biological methylation of metallic elements1 and the occurrence and cycling of organometals in the environment have been investigated in Japan during the 1950s and 1960s, where the ingestion of fish and shellfish contaminated with methylmercury compounds caused mercury poisoning2,3. Biomethylation ability has been demonstrated in bacteria, fungi and algae for As, Cd, Hg, Pb, Se, Sn, Te and Tl4-7. Naturally-occurring methylated species have been reported in estuaries and seawater for Sb8, As9, Ge10-13 and Sn14, although recent evidence suggests that some reports of methyltin species result from interferences by Ge and volatile sulphur compounds15. With the exception of Sb8, As9,12,16 and Ge11,12, there are no consistent estuarine or oceanic profiles for methylmetal compounds in the literature from which to judge their biogeochemical behaviour. Early investigations17-19 reported that methylgermanium species do not exist in the aquatic environment. Subsequently, we identified monomethylgermanium (MMGe) and dimethylgermanium (DMGe) in estuaries10,12, the Baltic Sea11 and the Bering and Sargasso seas13. We report here recent measurements of methylgermanium compounds in river water, estuaries, seawater and anoxic basins.

  7. Degradation of emerging contaminants from water under natural sunlight: The effect of season, pH, humic acids and nitrate and identification of photodegradation by-products.

    PubMed

    Koumaki, Elena; Mamais, Daniel; Noutsopoulos, Constantinos; Nika, Maria-Christina; Bletsou, Anna A; Thomaidis, Nikolaos S; Eftaxias, Alexander; Stratogianni, Georgia

    2015-11-01

    Both photodegradation and hydrolysis of non-steroidal anti-inflammatory drugs (NSAIDs) and endocrine disrupting chemicals (EDCs) were investigated in order to evaluate their photochemical fate in aquatic environment and to assess the effect of season and specific characteristics of water (pH, humic acids and nitrate concentration) on the removal of target EDCs and NSAIDs through photodegradation. An additional objective was the identification of the photodegradation by-products of specific NSAIDs and their dependence on irradiation time. Selected compounds' transformation was investigated under natural sunlight radiation while control experiments were conducted in the dark. As expected, most of compounds' degradation rate decreased with decreasing light intensity between two different experimental periods. Most of the tested compounds exhibited different rates of degradation during direct and indirect photolysis. The degradation rate of the selected compounds increased in the presence of NO3(-) and the photodegradation rate was higher for some compounds in alkaline than in acidic solution. The effect of humic acids' presence in the water depends on the absorbance spectrum of the compound and the produced photosensitizers. More specifically, humic acids act as inner filter toward most of the selected NSAIDs and as photosensitizers toward most of the EDCs. The results of the irradiation experiments in the presence of both humic acids and NO3(-), indicate that the direct photolysis is much more efficient than indirect photochemical processes. Finally, several degradation by-products of ketoprofen and diclofenac were identified in the samples, exposed to sunlight. The dependence of these by-products on radiation time is also demonstrated.

  8. Removal of antibiotics from water in the coexistence of suspended particles and natural organic matters using amino-acid-modified-chitosan flocculants: A combined experimental and theoretical study.

    PubMed

    Jia, Shuying; Yang, Zhen; Ren, Kexin; Tian, Ziqi; Dong, Chang; Ma, Ruixue; Yu, Ge; Yang, Weiben

    2016-11-01

    Contamination of trace antibiotics is widely found in surface water sources. This work delineates removal of trace antibiotics (norfloxacin (NOR), sulfadiazine (SDZ) or tylosin (TYL)) from synthetic surface water by flocculation, in the coexistence of inorganic suspended particles (kaolin) and natural organic matter (humic acid, HA). To avoid extra pollution caused by petrochemical products-based modification reagents, environmental-friendly amino-acid-modified-chitosan flocculants, Ctrp and Ctyr, with different functional aromatic-rings structures were employed. Jar tests at various pHs exhibited that, Ctyr, owning phenol groups as electron donors, was favored for elimination of cationic NOR (∼50% removal; optimal pH: 6; optimal dosage: 4mg/L) and TYL (∼60% removal; optimal pH: 7; optimal dosage: 7.5mg/L), due to π-π electron donator-acceptor (EDA) effect and unconventional H-bonds. Differently, Ctrp with indole groups as electron acceptor had better removal rate (∼50%) of SDZ anions (electron donator). According to correlation analysis, the coexisted kaolin and HA played positive roles in antibiotics' removal. Detailed pairwise interactions in molecular level among different components were clarified by spectral analysis and theoretical calculations (density functional theory), which are important for both the structural design of new flocculants aiming at targeted contaminants and understanding the environmental behaviors of antibiotics in water.

  9. Removal of antibiotics from water in the coexistence of suspended particles and natural organic matters using amino-acid-modified-chitosan flocculants: A combined experimental and theoretical study.

    PubMed

    Jia, Shuying; Yang, Zhen; Ren, Kexin; Tian, Ziqi; Dong, Chang; Ma, Ruixue; Yu, Ge; Yang, Weiben

    2016-11-01

    Contamination of trace antibiotics is widely found in surface water sources. This work delineates removal of trace antibiotics (norfloxacin (NOR), sulfadiazine (SDZ) or tylosin (TYL)) from synthetic surface water by flocculation, in the coexistence of inorganic suspended particles (kaolin) and natural organic matter (humic acid, HA). To avoid extra pollution caused by petrochemical products-based modification reagents, environmental-friendly amino-acid-modified-chitosan flocculants, Ctrp and Ctyr, with different functional aromatic-rings structures were employed. Jar tests at various pHs exhibited that, Ctyr, owning phenol groups as electron donors, was favored for elimination of cationic NOR (∼50% removal; optimal pH: 6; optimal dosage: 4mg/L) and TYL (∼60% removal; optimal pH: 7; optimal dosage: 7.5mg/L), due to π-π electron donator-acceptor (EDA) effect and unconventional H-bonds. Differently, Ctrp with indole groups as electron acceptor had better removal rate (∼50%) of SDZ anions (electron donator). According to correlation analysis, the coexisted kaolin and HA played positive roles in antibiotics' removal. Detailed pairwise interactions in molecular level among different components were clarified by spectral analysis and theoretical calculations (density functional theory), which are important for both the structural design of new flocculants aiming at targeted contaminants and understanding the environmental behaviors of antibiotics in water. PMID:27348257

  10. A new twist to a traditional approach to environmental monitoring: differentiation of oil sands process-affected waters and natural systems by comparison of individual organic acids

    NASA Astrophysics Data System (ADS)

    Scarlett, A.; Lengger, S.; West, C.; Rowland, S.

    2013-12-01

    Review panels of both the Canadian Federal and Alberta Provincial governments have recommended a complete overhaul of existing monitoring programs of the Athabasca oil sands industry and have called for a greater understanding of the potential impacts of mining activities to allow for future sustainable development. Due to the no release policy, it is critical that leakages of oil sands process-affected waters (OSPW) from tailings ponds can be differentiated from natural waters flowing through the McMurray formation into the Athabasca river system. Environmental monitoring of oil contamination usually entails profiling of known compounds, e.g. the US EPA list of priority Polycyclic Aromatic Hydrocarbons, but until now a similar approach has not been possible for OSPW due to its extreme complexity. It has been estimated that the number of carboxylic acids, historically referred to as ';naphthenic acids' (NA) in OSPW, to be in excess of 10000 compounds. Until recently, individual structures of these NA were unknown but analyses by tandem gas chromatography mass spectrometry (GCxGC-MS) have now begun to reveal the individual structures of alicyclic, aromatic and sulphur-containing acids within OSPWs stored in tailings ponds. Now that some individual structures present in OSPW are known and standards are available, a methodological approach similar to traditional oil monitoring can be developed using individual diamondoid NA and recently discovered diacids and applied to tailings pond OSPW and environmental waters. One obstacle to understanding whether the NA present in environmental groundwater samples are associated with particular tailings ponds is the lack of knowledge of the variability of OSPW within and between ponds. In the current study, GCxGC-MS analyses have been applied to statistically compare OSPWs of two industries, both temporally and spatially, using specific, known compounds as well as associated isomers. Although variation within individual ponds was

  11. Photodecomposition of humic acid and natural organic matter in swamp water using a TiO(2)-coated ceramic foam filter: potential for the formation of disinfection byproducts.

    PubMed

    Mori, Masanobu; Sugita, Tsuyoshi; Mase, Akinori; Funatogawa, Takahiro; Kikuchi, Masaru; Aizawa, Kazuhiko; Kato, Shigekazu; Saito, Yoichi; Ito, Tsukasa; Itabashi, Hideyuki

    2013-01-01

    This paper reports on the photodecomposition of aqueous humic acid (HA) by a TiO(2)-coated ceramic foam filter (TCF) reactor and on the potential for the formation of disinfection byproducts (DBPs) upon chlorination of the photocatalytically treated solutions. This photocatalytic reactor can also be applied to the removal of natural organic matter (NOM) in swamp waters. The proposed photocatalytic reaction system was operated as per standardized methodologies. First, the ability of the TCF to decompose HA (a representative compound of NOM) was evaluated from the changes in the total organic carbon (TOC) and UV(254) with the reaction time. Remarkably, TOC removal and UV(254) values ranging from 44% to 61% and from 60% to 83%, respectively, were achieved. The potential for the formation of DBPs (total trihalomethane and total haloacetic acid) by chlorination of the phototreated solution was strongly dependent on the TOC removal and UV(254) values in the solution. The degree of photodecomposition of NOMs in the swamp water samples and the DBP formation potential showed similar trends as in the case of the standard solutions containing HA. The method used in this study could be effectively used to evaluate the efficiency of TCF for reducing HA and NOM, while suppressing the formation of DBP products.

  12. Iron buffer system in the water column and partitioning in the sediments of the naturally acidic Lake Caviahue, Neuquén, Argentina

    NASA Astrophysics Data System (ADS)

    Cabrera, J. M.; Diaz, M. M.; Schultz, S.; Temporetti, P.; Pedrozo, F.

    2016-05-01

    Sedimentary iron partitioning was studied for five sediment strata (16 cm depth) at three sampling sites of the naturally-occurring acidic Lake Caviahue (Patagonia, Argentina). Additionally, water column iron was modeled based on five-year period input loadings to study a possible iron buffer system. The partition coefficient between the water column and the total iron content of the sediments was also addressed. Sedimentary iron was found to be distributed, on average, in the following forms: exchangeable (6%), iron oxides (4%), pyrite and reactive organic matter (38%) and residual (non-andesitic) materials with a high content of humic acids (52%). Furthermore, we found that the dissolved iron in the lake was nearly constant throughout the five year period we studied. This is consistent with the existence of an iron buffer system in the lake at pH between 2.0 and 3.0, which may cause differential iron precipitation at the delta of the volcanic river with respect to the deeper northern and southern arms. Sedimentary iron measurements taken at the delta further support the existence of a buffer system, where it was found that the iron content in the sub-superficial stratum (2 cm) was double that of the remainder of the vertical profile at the same site.

  13. Microbiological quality of natural waters.

    PubMed

    Borrego, J J; Figueras, M J

    1997-12-01

    Several aspects of the microbiological quality of natural waters, especially recreational waters, have been reviewed. The importance of the water as a vehicle and/or a reservoir of human pathogenic microorganisms is also discussed. In addition, the concepts, types and techniques of microbial indicator and index microorganisms are established. The most important differences between faecal streptococci and enterococci have been discussed, defining the concept and species included. In addition, we have revised the main alternative indicators used to measure the water quality.

  14. Influence of acid rain upon water plumbosolvency.

    PubMed Central

    Moore, M R

    1985-01-01

    The West of Scotland has had particular problems in the past associated with soft acidic water supplies and uptake of lead from domestic plumbing systems by such water. As a consequence of this, health problems related to overexposure to lead have been identified. The current debate on acidification of ground waters by acid rain is therefore particularly pertinent to this area. Studies have shown that even a modest decrease in pH will result in very substantial increase in plumbosolvency. This was found to be of particular importance in the city of Glasgow and town of Ayr, where prior to water treatment, pH values were 6.3 and 5.4, respectively, and where, consequentially, large numbers of homes did not comply with lead in water standards. Closed-loop lime-dosing systems were introduced in both Glasgow and Ayr to increase the pH with immediate decrease in the lead content of the water and, subsequently, blood lead concentrations of the subjects living in these areas. Such closed-loop systems will compensate for any acidity in water supplies, whether of natural origin or originating from acid rain precipitation. However, when such treatment has not been applied, any increase in water acidity due to acid rain which is, in many cases, already unacceptable. which is, in many cases, already unacceptable. PMID:4076078

  15. Influence of acid rain upon water plumbosolvency.

    PubMed

    Moore, M R

    1985-11-01

    The West of Scotland has had particular problems in the past associated with soft acidic water supplies and uptake of lead from domestic plumbing systems by such water. As a consequence of this, health problems related to overexposure to lead have been identified. The current debate on acidification of ground waters by acid rain is therefore particularly pertinent to this area. Studies have shown that even a modest decrease in pH will result in very substantial increase in plumbosolvency. This was found to be of particular importance in the city of Glasgow and town of Ayr, where prior to water treatment, pH values were 6.3 and 5.4, respectively, and where, consequentially, large numbers of homes did not comply with lead in water standards. Closed-loop lime-dosing systems were introduced in both Glasgow and Ayr to increase the pH with immediate decrease in the lead content of the water and, subsequently, blood lead concentrations of the subjects living in these areas. Such closed-loop systems will compensate for any acidity in water supplies, whether of natural origin or originating from acid rain precipitation. However, when such treatment has not been applied, any increase in water acidity due to acid rain which is, in many cases, already unacceptable. which is, in many cases, already unacceptable.

  16. Photochemical behavior of carbon nanotubes in natural waters: reactive oxygen species production and effects on •OH generation by Suwannee River fulvic acid, nitrate, and Fe (III).

    PubMed

    Zhou, Lei; Zhang, Ya; Wang, Qi; Ferronato, Corinne; Yang, Xi; Chovelon, Jean-Marc

    2016-10-01

    The photochemical activities of three kinds of carbon nanotubes (CNTs) were investigated in the present study. Efficient procedures of dispersing the three kinds of carbon nanotubes in water were established, and the quantitative analysis methods were also developed by TOC-absorbance method. High pH value or low ionic strength of the colloidal solutions facilitated the dispersion of CNTs. The suspensions of three kinds of CNTs could generate singlet oxygen ((1)O2) and hydroxyl radical (•OH) under irradiation of simulated sunlight, while superoxide radical (O2 (•-)) was not detected. The steady-state concentrations of (1)O2 and •OH generated by these CNTs were also determined. The presence of CNTs in natural waters can affect the photochemical behavior of water constituents, such as nitrate, dissolved organic matter, and Fe(3+). Specifically, in nitrate solution, the presence of CNTs could inhibit the generation of •OH by nitrate through light screening effect, while the quenching effect of hydroxyl radicals by CNTs was not observed. Besides light screening effect, the three kinds of CNTs used in the experiments also have a strong inhibiting effect on the ability of DOM to produce •OH by binding to the active sites. Moreover, the adsorption of Fe(3+) on MWCNT-OH and MWCNT-COOH could lead to its inactivation of formation of •OH in acidic conditions. However, the presence of the three kinds of CNTs did not affect the ligand-to-metal charge transfer (LMCT) reaction of DOM-Fe (III) complex.

  17. Anticancer agents derived from natural cinnamic acids.

    PubMed

    Su, Ping; Shi, Yaling; Wang, Jinfeng; Shen, Xiuxiu; Zhang, Jie

    2015-01-01

    Cancer is the most dangerous disease that causes deaths all over the world. Natural products have afforded a rich source of drugs in a number of therapeutic fields including anticancer agents. Many significant drugs have been derived from natural sources by structural optimization of natural products. Cinnamic acid has gained great interest due to its antiproliferative, antioxidant, antiangiogenic and antitumorigenic potency. Currently it has been observed that cinnamic acid and its analogs such as caffeic acid, sinapic acid, ferulic acid, and isoferulic acid display various pharmacological activities, such as immunomodulation, anti-inflammation, anticancer and antioxidant. They have served to be the major sources of potential leading anticancer compounds. In this review, we focus on the anticancer potency of cinnamic acid derivatives and novel strategies to design these derivatives. We hope this review will be useful for researchers who are interested in developing anticancer agents.

  18. Acidophilic, heterotrophic bacteria of acidic mine waters

    SciTech Connect

    Wichlacz, P.L.; Unz, R.F.

    1981-05-01

    Obligately acidophilic, heterotrophic bacteria were isolated both from enrichment cultures developed with acidic mine water and from natural mine drainage. The bacteria were grouped by the ability to utilize a number of organic acids as sole carbon sources. None of the strains were capable of chemolithotrophic growth on inorganic reduced iron and sulfur compounds. All bacteria were rod shaped, gram negative, nonencapsulated, motile, capable of growth at pH 2.6 but not at pH 6.0, catalase and oxidase positive, strictly aerobic, and capable of growth on citric acid. The bacteria were cultivatable on solid nutrient media only if agarose was employed as the hardening agent. Bacterial densities in natural mine waters ranged from approximately 20 to 250 cells per ml, depending upon source and culture medium.

  19. Natural radioactivity in phosphates, phosphogypsum and natural waters in Morocco.

    PubMed

    Azouazi, M; Ouahidi, Y; Fakhi, S; Andres, Y; Abbe, J C; Benmansour, M

    2001-01-01

    The contents of natural radionuclides (uranium, actinium and thorium series) were measured in sedimentary phosphate rock samples using high-resolution gamma spectrometry. Data obtained for uranium content (ppm) were compared with the results obtained by a method based on the measurements using solid-state nuclear track detectors (SSNTD) in the same samples. The potential leaching of radionuclides from sedimentary phosphate rock during the industrial production of the phosphoric acid was studied. The process of leaching of the radioisotopes from phosphogypsum was discussed. A method for the direct alpha counting of 226Ra thin source, elaborated by the deposition of Ra from aqueous solutions on manganese oxides film deposited on polyvinyl support, have been developed and applied for the determination of 226Ra in natural water samples. The results show that only the water sample from the mine area reveals the presence of 226Ra at a level of about 0.2 Bq l-1. PMID:11378917

  20. Natural radioactivity in phosphates, phosphogypsum and natural waters in Morocco.

    PubMed

    Azouazi, M; Ouahidi, Y; Fakhi, S; Andres, Y; Abbe, J C; Benmansour, M

    2001-01-01

    The contents of natural radionuclides (uranium, actinium and thorium series) were measured in sedimentary phosphate rock samples using high-resolution gamma spectrometry. Data obtained for uranium content (ppm) were compared with the results obtained by a method based on the measurements using solid-state nuclear track detectors (SSNTD) in the same samples. The potential leaching of radionuclides from sedimentary phosphate rock during the industrial production of the phosphoric acid was studied. The process of leaching of the radioisotopes from phosphogypsum was discussed. A method for the direct alpha counting of 226Ra thin source, elaborated by the deposition of Ra from aqueous solutions on manganese oxides film deposited on polyvinyl support, have been developed and applied for the determination of 226Ra in natural water samples. The results show that only the water sample from the mine area reveals the presence of 226Ra at a level of about 0.2 Bq l-1.

  1. Hydroquinone-Mediated Redox Cycling of Iron and Concomitant Oxidation of Hydroquinone in Oxic Waters under Acidic Conditions: Comparison with Iron-Natural Organic Matter Interactions.

    PubMed

    Jiang, Chao; Garg, Shikha; Waite, T David

    2015-12-15

    Interactions of 1,4-hydroquinone with soluble iron species over a pH range of 3-5 in the air-saturated and partially deoxygenated solution are examined here. Our results show that 1,4-hydroquinone reduces Fe(III) in acidic conditions, generating semiquinone radicals (Q(•-)) that can oxidize Fe(II) back to Fe(III). The oxidation rate of Fe(II) by Q(•-)increases with increase in pH due to the speciation change of Q(•-) with its deprotonated form (Q(•-)) oxidizing Fe(II) more rapidly than the protonated form (HQ(•)). Although the oxygenation of Fe(II) is negligible at pH < 5, O2 still plays an important role in iron redox transformation by rapidly oxidizing Q(•-) to form benzoquinone (Q). A kinetic model is developed to describe the transformation of quinone and iron under all experimental conditions. The results obtained here are compared with those obtained in our previous studies of iron-Suwannee River fulvic acid (SRFA) interactions in acidic solutions and support the hypothesis that hydroquinone moieties can reduce Fe(III) in natural waters. However, the semiquinone radicals generated in pure hydroquinone solution are rapidly oxidized by dioxygen, while the semiquinone radicals generated in SRFA solution are resistant to oxidation by dioxygen, with the result that steady-state semiquinone concentrations in SRFA solutions are 2-3 orders of magnitude greater than in solutions of 1,4-hydroquinone. As a result, semiquinone moieties in SRFA play a much more important role in iron redox transformations than is the case in solutions of simple quinones such as 1,4-hydroquinone. This difference in the steady-state concentration of semiquinone species has a dramatic effect on the cycling of iron between the +II and +III oxidation states, with iron turnover frequencies in solutions containing SRFA being 10-20 times higher than those observed in solutions of 1,4-hydroquinone.

  2. Modeling the acid-base properties of glutathione in different ionic media, with particular reference to natural waters and biological fluids.

    PubMed

    Cigala, Rosalia Maria; Crea, Francesco; De Stefano, Concetta; Lando, Gabriele; Milea, Demetrio; Sammartano, Silvio

    2012-08-01

    The acid-base properties of γ-L-glutamyl-L-cysteinyl-glycine (glutathione, GSH) were determined by potentiometry (ISE-H(+), glass electrode) in pure NaI((aq)) and in NaCl((aq))/MgCl(2(aq)), and NaCl((aq))/CaCl(2(aq)) mixtures, at T = 298.15 K and different ionic strengths (up to I(c) ~ 5.0 mol L(-1)). In addition, the activity coefficients of glutathione were also determined by the distribution method at the same temperature in various ionic media (LiCl((aq)), NaCl((aq)), KCl((aq)), CsCl((aq)), MgCl(2(aq)), CaCl(2(aq)), NaI((aq))). The results obtained were also used to calculate the Specific ion Interaction Theory (SIT) and Pitzer coefficients for the dependence on medium and ionic strength of glutathione species, as well as the formation constants of weak Mg(j)H( i )(GSH)((i+2j-3)) and Ca(j)H(i)(GSH)((i+2j-3)) complexes. Direct calorimetric titrations were also carried out in pure NaCl((aq)) and in NaCl((aq))/CaCl(2(aq)) mixtures at different ionic strengths (0.25 ≤ I (c )/mol L(-1) ≤ 5.0) in order to determine the enthalpy changes for the protonation and complex formation equilibria in these media at T = 298.15 K. Results obtained are useful for the definition of glutathione speciation in any aqueous media containing the main cations of natural waters and biological fluids, such as Na(+), K(+), Mg(2+), and Ca(2+). Finally, this kind of systematic studies, where a series of ionic media (e.g., all alkali metal chlorides) is taken into account in the determination of various thermodynamic parameters, is useful for the definition of some trends in the thermodynamic behavior of glutathione in aqueous solution. PMID:21997535

  3. Modeling the acid-base properties of glutathione in different ionic media, with particular reference to natural waters and biological fluids.

    PubMed

    Cigala, Rosalia Maria; Crea, Francesco; De Stefano, Concetta; Lando, Gabriele; Milea, Demetrio; Sammartano, Silvio

    2012-08-01

    The acid-base properties of γ-L-glutamyl-L-cysteinyl-glycine (glutathione, GSH) were determined by potentiometry (ISE-H(+), glass electrode) in pure NaI((aq)) and in NaCl((aq))/MgCl(2(aq)), and NaCl((aq))/CaCl(2(aq)) mixtures, at T = 298.15 K and different ionic strengths (up to I(c) ~ 5.0 mol L(-1)). In addition, the activity coefficients of glutathione were also determined by the distribution method at the same temperature in various ionic media (LiCl((aq)), NaCl((aq)), KCl((aq)), CsCl((aq)), MgCl(2(aq)), CaCl(2(aq)), NaI((aq))). The results obtained were also used to calculate the Specific ion Interaction Theory (SIT) and Pitzer coefficients for the dependence on medium and ionic strength of glutathione species, as well as the formation constants of weak Mg(j)H( i )(GSH)((i+2j-3)) and Ca(j)H(i)(GSH)((i+2j-3)) complexes. Direct calorimetric titrations were also carried out in pure NaCl((aq)) and in NaCl((aq))/CaCl(2(aq)) mixtures at different ionic strengths (0.25 ≤ I (c )/mol L(-1) ≤ 5.0) in order to determine the enthalpy changes for the protonation and complex formation equilibria in these media at T = 298.15 K. Results obtained are useful for the definition of glutathione speciation in any aqueous media containing the main cations of natural waters and biological fluids, such as Na(+), K(+), Mg(2+), and Ca(2+). Finally, this kind of systematic studies, where a series of ionic media (e.g., all alkali metal chlorides) is taken into account in the determination of various thermodynamic parameters, is useful for the definition of some trends in the thermodynamic behavior of glutathione in aqueous solution.

  4. Acid lakes from natural and anthropogenic causes

    SciTech Connect

    Patrick, R.; Binetti, V.P.; Halterman, S.G.

    1981-01-30

    Lakes may be acid because of natural ecological conditions or because of anthropogenic activities. Apparently there has been a recent increase in acidity of many lakes in the northeastern United States. Factors that may be contributing to this increase include the use by utilities of precipitators, sulfur scrubbers, and tall stacks; the use of petroleum; and methods of combustion of fossil fuels.

  5. Interfacial action of natural surfactants in oil/water systems

    SciTech Connect

    Ogino, K.; Onishi, M.

    1981-09-01

    This paper concerns the tendency of a few natural surfactants at the oil/water interface to induce spontaneous emulsification. N-paraffin (n-dodecane), liquid triglycerides (oleic safflower oil and corn oil), and liquid fatty acids (oleic acid and linoleic acid) were used as the oil phase and distilled water was used as the water phase. Natural surfactants such as cholesterol, lecithin, and oleic acid were applied to the systems as the oil-soluble additives. Lecithin was the most strongly effective in reducing the interfacial tension of the oil/water systems, and cholesterol was effective at the second strength. The oil/water interface of the systems containing the oil-soluble additives changed in various ways as observed by microscopy and the unaided eye. The most remarkable change was found in the system of glycerides containing cholesterol in contact with water, in which crystals of cholesterol were formed at the interface. 13 references.

  6. Nature and origins of acidity in bogs

    SciTech Connect

    Urban, N.R.

    1987-01-01

    To elucidate the causes of acidity in bogs, all of the processes generating and consuming acidity in a small peat bog in northern Minnesota were measured. These processes include ion exchange, plant nutrient uptake, atmospheric deposition, decomposition, organic acid production, sulfate reduction, and denitrification. Organic acid production was found to be the dominant source of acidity, responsible for the low pH of bog waters and the high acidity in the outflow. Net biological uptake (NBU) is the next largest source of acidity. Ion exchange accounts for only about 40% of the NBU-acidity. Plant uptake and ion exchange are much larger sources of acidity on an annual basis, but much of this acidity is neutralized by decomposition. Sulfate reduction and denitrification are quantitatively unimportant at this site because inputs (NO/sub 3//sup -/ and SO/sub 4/=) are low. Bog water samples and peat cores from bogs across northeastern North America were analyzed to determine if geographic trends in the rates of acidity-generating and -consuming processes exist. Rates of organic acid production varied little across the transect. Higher values of NBU-acidity were observed in maritime bogs than in midcontinental bogs. The effects of transformations of sulfur and nitrogen on the hydrogen-ion cycle were examined in detail. Nitrate appears to be taken up by bryophytes and little is lost to denitrification. Alkalinity from nitrate uptake is low. In contrast, there is a dynamic cycle of oxidation and reduction of sulfur within bogs. Inorganic forms of sulfur are not important storage pools in peat; 35% of the total sulfur input is accumulated as organic S.

  7. Simulation of Natural Acid Sulfate Weathering in an Alpine Watershed

    NASA Astrophysics Data System (ADS)

    Bassett, R. L.; Miller, William R.; McHugh, John; Catts, John G.

    1992-09-01

    Streams with acidic sulfate compositions (pH less than 3.5) are naturally generated in the alpine Geneva Creek Basin of the southern Rocky Mountains, an area underlain by Proterozoic metamorphic and igneous rocks that are intruded by Tertiary felsic stocks with associated pyritic alteration. These naturally acidic waters are similar in composition to more familiar man-made acid mine waters or to surface waters acidified by sulfate precipitation. Detailed study of the stream compositions has revealed the principal reactions driving the weathering process and was used to estimate the relative effects of snowpack ionic input versus the solute contribution from acid attack in soil zones and groundwater. In the Geneva Creek Basin, atmospheric sources of solute represent a minor component to the stream water composition, except for chloride, which can be used to determine the fraction of contribution. The weathering process is a balance between oxidation of sulfides, dissolution of silicates, formation of the clay minerals vermiculite, kaolinite, and smectite, carbonate neutralization, and precipitation of ferric and aluminum oxyhydroxides and aluminum sulfate. The chemical analyses of snow samples, multiple samples of water from Geneva Creek and its tributaries, and the composition of primary and secondary minerals identified in the basin serve as input to a mass balance geochemical model, which facilitates the interpretation of the principal geochemical processes.

  8. (Acidic deposition: Its nature and impacts)

    SciTech Connect

    Cook, R.B.; Turner, R.S. ); Ryan, P.F. )

    1990-10-18

    The travelers presented papers on various aspects of modeling performed as part of the US National Acidic Precipitation Assessment Program (NAPAP) at the Fourth International Conference on Acidic Deposition: Its Nature and Impacts. The meeting was sponsored by the Royal Society of Edinburgh and was attended by over 800 scientists, primarily from Europe and North America. The conference focused on nine aspects of the nature and impacts of atmospheric pollutants, including ozone: chemistry of atmospheric pollutants; processes controlling the deposition of pollutants; effects of pollutants on soils; physiology of plant responses to pollutants; effects of pollutants in agricultural and natural or seminatural ecosystems; atmospheric pollutants and forests; effects of pollutants on the chemistry of freshwater streams and lakes; effects of pollutants on freshwater plants and animals; and effects of pollutants, indoors and outdoors, on materials and buildings.

  9. Microwave treatment of naphthenic acids in water.

    PubMed

    Mishra, Sabyasachi; Meda, Venkatesh; Dalai, Ajay K; Headley, John V; Peru, Kerry M; McMartin, Dena W

    2010-08-01

    Naphthenic acids (NAs) are natural constituents of bitumen and crude oil. These compounds are concentrated as part of the oil sands process water (OSPW) during petroleum refining and separation from oil sands. NAs are considered among the major water contaminants in OSPW due to their toxicity and environmental recalcitrance. A laboratory scale microwave system was developed and experiments were conducted to determine the efficiency of NA degradation during microwave treatment. The effects of water source and quality (deionized lab water and river water) and of TiO(2) catalyst in the degradation process were also investigated. Degradation kinetic parameters for both total NAs and individual z-family were calculated. The microwave system degraded OSPW NAs and commercial Fluka NAs in river water in the presence of TiO(2) rapidly, producing half-life values of 3.32 and 3.61 hours, respectively. Toxicity assessments of the NA samples pre-and post-treatment indicated that the microwave system reduced overall toxicity of water containing Fluka NAs from high (5 min. IC(50) v/v = 15.85%) to moderate (5 min. IC(50) v/v = 36.45%) toxicity levels. However, a slight increase in toxicity was noted post-treatment in OSPW NAs.

  10. Rotational Study of Natural Amino Acid Glutamine

    NASA Astrophysics Data System (ADS)

    Varela, Marcelino; Cabezas, Carlos; Alonso, José L.

    2014-06-01

    Recent improvements in laser ablation molecular beam Fourier transform microwave spectroscopy (LA-MB-FTMW) have allowed the investigation of glutamine (COOH-CH(NH2)-CH2-CH2-CONH2), a natural amino acid with a long polar side chain. One dominant structure has been detected in the rotational spectrum. The nuclear quadrupole hyperfine structure of two 14N nuclei has been totally resolved allowing the conclusive identification of the observed species.

  11. Modeling complexometric titrations of natural water samples.

    PubMed

    Hudson, Robert J M; Rue, Eden L; Bruland, Kenneth W

    2003-04-15

    Complexometric titrations are the primary source of metal speciation data for aquatic systems, yet their interpretation in waters containing humic and fulvic acids remains problematic. In particular, the accuracy of inferred ambient free metal ion concentrations and parameters quantifying metal complexation by natural ligands has been challenged because of the difficulties inherent in calibrating common analytical methods and in modeling the diverse array of ligands present. This work tests and applies a new method of modeling titration data that combines calibration of analytical sensitivity (S) and estimation of concentrations and stability constants for discrete natural ligand classes ([Li]T and Ki) into a single step using nonlinear regression and a new analytical solution to the one-metal/two-ligand equilibrium problem. When applied to jointly model data from multiple titrations conducted at different analytical windows, it yields accurate estimates of S, [Li]T, Ki, and [Cu2+] plus Monte Carlo-based estimates of the uncertainty in [Cu2+]. Jointly modeling titration data at low-and high-analytical windows leads to an efficient adaptation of the recently proposed "overload" approach to calibrating ACSV/CLE measurements. Application of the method to published data sets yields model results with greater accuracy and precision than originally obtained. The discrete ligand-class model is also re-parametrized, using humic and fulvic acids, L1 class (K1 = 10(13) M(-1)), and strong ligands (L(S)) with K(S) > K1 as "natural components". This approach suggests that Cu complexation in NW Mediterranean Sea water can be well represented as 0.8 +/- 0.3/0.2 mg humic equiv/L, 13 +/- 1 nM L1, and 2.5 +/- 0.1 nM L(S) with [CU]T = 3 nM. In coastal seawater from Narragansett Bay, RI, Cu speciation can be modeled as 0.6 +/- 0.1 mg humic equiv/L and 22 +/- 1 nM L1 or approximately 12 nM L1 and approximately 9 nM L(S), with [CU]T = 13 nM. In both waters, the large excess

  12. Sulfur speciation in natural hydrothermal waters, Iceland

    NASA Astrophysics Data System (ADS)

    Kaasalainen, Hanna; Stefánsson, Andri

    2011-05-01

    oxidized to SO 32- and S 2O 32- and eventually to SO 42- at pH >8. In near-neutral hydrothermal waters the oxidation of S 2- and the interaction of S 2- and S 0 resulting in the formation of S x2- are considered important. At lower pH values the reactions seemed to proceed relatively rapidly to SO 42- and the sulfur chemistry of acid-sulfate pools was dominated by SO 42-, which corresponded to >99% of S TOT. The results suggest that the aqueous speciation of sulfur in natural hydrothermal waters is dynamic and both kinetically and source-controlled and cannot be estimated from thermodynamic speciation calculations.

  13. Natural mineral waters, curative-medical waters and their protection

    NASA Astrophysics Data System (ADS)

    Fricke, M.

    1993-10-01

    In Europe different types of water are marketed, each strictly defined by EC Directive 80/777 (Natural Mineral Water, Spring and Table Water) or 80/778 (Drinking Water). In Germany, an additional type of water is common in the market: curative/medical water. Product quality and safety, registration as medicine, and pharmaceutical control are defined by the German Federal Medicine Act. A medical water is treated as any other medicine and may be sold only in pharmacies. The use of any water in Germany is controlled and strictly regulated by the Federal Water Act (Fricke 1981). The following requirements are set by the act: (1) No water use without a permit, which is limited in time and quantity. (2) No single or juristic person may own water. (3) Water resources of public interest and their recharge areas are to be protected by the definition of water protection zones. (Natural mineral water is not of public interest and therefore is not required to be protected by the definition of water protection zones, although it represents a market value of more than US2 billion. Medical water is of public interest). The definition of water protection zones impacts private property rights and has to be handled carefully. In order to protect water resources, sometimes the economic basis of a traditional industrial and/or agricultural infrastructure is destroyed. The concerns and needs all citizens, including industry, must be considered in analyzing the adequacy of water protection zones.

  14. Sulfuric Acid and Water: Paradoxes of Dilution

    ERIC Educational Resources Information Center

    Leenson, I. A.

    2004-01-01

    On equilibrium properties of aqueous solutions of sulfuric acid, Julius Thomsen has marked that the heat evolved on diluting liquid sulfuric acid with water is a continuous function of the water used, and excluded absolutely the acceptance of definite hydrates as existing in the solution. Information about thermochemical measurement, a discussion…

  15. Acid rain and drinking water degradation.

    PubMed

    Middleton, P; Rhodes, S L

    1984-03-01

    Acid deposition-induced drinking water degradation is discussed with respect to the geographical extent of and the potential for dealing with possibly adverse human health impacts. Qualitative evidence from the northeastern United States and Sweden strongly suggests the existence of a linkage between these two environmental concerns. It is argued that water treatment and reduction of acid rain as solutions to the problem of water toxicity need closer evaluation. More research into the causal link is warranted since the addition of human health impacts to acid rain's environmental insults could have a significant bearing on discussions relating to acid rain controls.

  16. Analysis of Natural Buffer Systems and the Impact of Acid Rain

    ERIC Educational Resources Information Center

    Powers, David C.; Yoder, Claude H.; Higgs, Andrew T.; Obley, Matt L.; Hess, Kenneth R.; Leber, Phyllis A.

    2005-01-01

    The environmental significance of acid rain on water systems of different buffer capacities is discussed. The most prevalent natural buffer system is created by the equilibrium between carbonate ions and carbon dioxide.

  17. Silicone hydrogels grafted with natural amino acids for ophthalmological application.

    PubMed

    Xu, Chen; He, Ruiyu; Xie, Binbin; Ismail, Muhammad; Yao, Chen; Luan, Jie; Li, Xinsong

    2016-09-01

    In this report, protein repelling silicone hydrogels with improved hydrophilicity were prepared by photo-polymerization of silicone-containing monomer and glycidyl methacrylate followed by grafting zwitterionic amino acids. The grafted silicone hydrogels possessed excellent hydrophilic surfaces due to the enrichment of amino acids, which was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle, and equilibrium water content measurements. Remarkable resistance to bovine serum albumin and lysozyme fouling was observed for the silicone hydrogels immobilized with neutrally charged amino acids because of the formation of zwitterionic surfaces with pairs of protonated secondary ammonium cations and deprotonated carboxyl anions. Meanwhile, the silicone hydrogels grafted with positively or negatively charged amino acids were able to repulse same charged protein with reduced deposition and attract oppositely charged protein with increased adsorption. Preliminary cytotoxicity test indicated that the zwitterionic silicone hydrogels were non-cytotoxic. Similarly, three types of natural amino acids, including serine, aspartic acid and histidine, modified silicone hydrogel contact lenses exhibited excellent hydrophilicity and non-damage to the rabbit's eyes, but only serine modified zwitterionic contact lens showed superior protein fouling resistance compared with the current commercial hydrogel contact lens, which may have great potential application in ophthalmology.

  18. Formation of acrylic acid from lactic acid in supercritical water

    SciTech Connect

    Mok, W.S.L.; Antal, M.J. Jr. ); Jones, M. Jr. )

    1989-09-15

    Supercritical (SC) water is an unusual medium in which fast and specific heterolytic reactions can be conducted at temperatures as high as 400{degree}C. In supercritical water, lactic acid decomposes into gaseous and liquid products via three primary reaction pathways. Products of the acid-catalyzed heterolytic decarbonylation pathway are carbon monoxide, water, and acetaldehyde. Products of the homolytic, decarboxylation pathway are carbon dioxide, hydrogen, and acetaldehyde. Products of the heterolytic, dehydration pathway are acrylic acid and water. The intramolecular nucleophilic displacement of the {alpha}-hydroxyl by the carbonyl group of lactic acid, producing {alpha}-propiolactone as an unstable intermediate which subsequently rearranges to become the unsaturated acid, is a likely mechanism for acrylic acid formation, although an intramolecular E2 elimination initiated by attack of the carbonyl oxygen on a methyl hydrogen cannot be ruled out. Support for the former mechanism comes in part from the observed 100% relative yield of acrylic acid from {beta}-propiolactone in SC water.

  19. [Electrochemical purification of natural waters from humic compounds].

    PubMed

    Malysheva, A G; Abramov, E G; Rastiannikov, E G

    2006-01-01

    The article presents a comparative analysis of chemical substances which are formed in natural waters with different concentrations of humic and fulvic acids under the influence of ozone and chlorine, as a result of electrochemical processing. The authors present thermodynamic evaluation of the probability of the formation of transformation products under the influence of oxidizing reagents and during anode oxidation, and demonstrate the effectiveness of electrochemical purification of natural waters from humic compounds by cathode activated carbon. The scheme of a device to perform this process has been developed.

  20. Incorporation of stratospheric acids into water ice

    NASA Technical Reports Server (NTRS)

    Elliott, Scott; Turco, Richard P.; Toon, Owen B.; Hamill, Patrick

    1990-01-01

    Hydrochloric and hydrofluoric acids are absorbed within the water ice lattice at mole fractions maximizing below 0.00001 and 0.0001 in a variety of solid impurity studies. The absorption mechanism may be substitutional or interstitial, leading in either case to a weak permeation of stratospheric ices by the acids at equilibrium. Impurities could also inhabit grain boundaries, and the acid content of atmospheric ice crystals will then depend on details of their surface and internal microstructures. Limited evidence indicates similar properties for the absorption of HNO3. Water ice lattices saturated with acid cannot be a significant local reservoir for HCl in the polar stratosphere.

  1. Biological water oxidation: lessons from nature.

    PubMed

    Najafpour, Mohammad Mahdi; Moghaddam, Atefeh Nemati; Allakhverdiev, Suleyman I; Govindjee

    2012-08-01

    Hydrogen production by water splitting may be an appealing solution for future energy needs. To evolve hydrogen efficiently in a sustainable manner, it is necessary first to synthesize what we may call a 'super catalyst' for water oxidation, which is the more challenging half reaction of water splitting. An efficient system for water oxidation exists in the water oxidizing complex in cyanobacteria, algae and plants; further, recently published data on the Manganese-calcium cluster have provided details on the mechanism and structure of the water oxidizing complex. Here, we have briefly reviewed the characteristics of the natural system from the standpoint of what we could learn from it to produce an efficient artificial system. In short, to design an efficient water oxidizing complex for artificial photosynthesis, we must learn and use wisely the knowledge about water oxidation and the water oxidizing complex in the natural system. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.

  2. Acidity of Strong Acids in Water and Dimethyl Sulfoxide.

    PubMed

    Trummal, Aleksander; Lipping, Lauri; Kaljurand, Ivari; Koppel, Ilmar A; Leito, Ivo

    2016-05-26

    Careful analysis and comparison of the available acidity data of HCl, HBr, HI, HClO4, and CF3SO3H in water, dimethyl sulfoxide (DMSO), and gas-phase has been carried out. The data include experimental and computational pKa and gas-phase acidity data from the literature, as well as high-level computations using different approaches (including the W1 theory) carried out in this work. As a result of the analysis, for every acid in every medium, a recommended acidity value is presented. In some cases, the currently accepted pKa values were revised by more than 10 orders of magnitude. PMID:27115918

  3. Degradability of fluorapatite-leucite ceramics in naturally acidic agents.

    PubMed

    Kukiattrakoon, Boonlert; Hengtrakool, Chanothai; Kedjarune-Leggat, Ureporn

    2010-10-01

    This study was conducted to evaluate the titratable acidity and effect of naturally acidic agents on the surface microhardness, elemental composition, and surface morphology of fluorapatite-leucite ceramics. One hundred and ten ceramic disks (IPS d.SIGN), 12.0 mm in diameter and 2.0 mm in thickness, were fabricated. Before immersion, the baseline data of Vickers microhardness and elemental composition were recorded. Four groups were immersed in acidic agents (citrate buffer solution, green mango juice, and pineapple juice) and deionized water (control) at 37ºC for 168 hours, whereas one group was immersed in 4% acetic acid at 80ºC for 168 hours. After immersion, specimens were evaluated and data were analyzed using one-way repeated ANOVA and Tukey's test (α=0.05). Microhardness values significantly decreased after immersion (p<0.05). In terms of elemental composition, the weight percentages of silicon, potassium, aluminum, and sodium also decreased after immersion (p<0.05). Results of this study showed that fluorapatite-leucite ceramics were affected by long-term immersion in acidic agents.

  4. Extraction and HPLC- UV Analysis of C60, C70, and [6,6]-phenyl C61-butyric acid methyl ester in Synthetic and Natural Waters

    EPA Science Inventory

    Studies have shown that C60 fullerene can form stable colloidal suspensions in water that result in C60 aqueous concentrations many orders of magnitude above C60's aqueous solubility; however, quantitative methods for the analysis of C60 and other fullerenes in environmental medi...

  5. Natural Attenuation of Metals from Acid Drainage in Surface Waters: Effects of Organic Matter in the Association of Arsenic to Hydrous Al and Fe Oxyhydroxides and Their Particle Size Distribution

    NASA Astrophysics Data System (ADS)

    Arce, G. J.; Pasten, P.; Coquery, M.; Abarca, M. I.; Montecinos, M.

    2015-12-01

    The presence of toxic metals in watersheds affected by acid drainage (AD) imposes a challenge for sustainable supply of water for cities, agriculture and industry. The formation and settling of metal-rich HFO (hydrous ferric oxides) and HAO (hydrous aluminum oxides) is a relevant mechanism for the attenuation of dissolved metals from AD, particularly for arsenic. Organic matter is known to alter the chemical speciation and key physical properties like particle size distribution (PSD) and settling velocity of HFO and HAO particle suspensions. However, available experimental studies focus either on chemical or physical properties. We used a suite of analytical techniques to probe the effects of organic matter on particle suspensions formed in natural waters and in laboratory model systems. Dissolved organic matter was added at different concentrations (0, 0.1, 0.3, 0.6, 1 and 1.5 mg C/L) to synthetic AD before neutralization with alkaline solutions. PSD and average particle size were measured with laser scattering transmissometry (LISST), while organic matter was characterized by total organic carbon (TOC) and UV-VIS spectrometry. Larger concentrations of organic matter lead to the formation of particle suspensions with larger particle volume and size. When 1.5 mg C/L were added, the total particle volume concentration increased from 0.67 to 23.74 μL/L, while the mean particle size increased from 102 to 176 μm. These results suggests that organic matter influences the fate of metals from AD. Undergoing measurements include total and dissolved metal analyses with total reflection X-ray fluorescence (TXRF) and ICP-OES to confirm increased removal of dissolved arsenic. The results from this research are necessary to understand the processes governing natural attenuation of metal contamination in fluvial systems affected by AD and to serve as the basis for enhanced natural attenuation schemes. The authors acknowledge funding from Fondecyt 1130936.

  6. Going natural: Effective weed control in squash with pelargonic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pelargonic acid, a natural, but not certified organic herbicide, has been shown to be phytotoxic, acting as a contact herbicide, injuring and killing plants through cell membrane disruption. Pelargonic acid, a fatty acid also known as nonanoic acid, is a nine-carbon chained organic compound found in...

  7. Base-acid hybrid water electrolysis.

    PubMed

    Chen, Long; Dong, Xiaoli; Wang, Fei; Wang, Yonggang; Xia, Yongyao

    2016-02-21

    A base-acid hybrid electrolytic system with a low onset voltage of 0.78 V for water electrolysis was developed by using a ceramic Li-ion exchange membrane to separate the oxygen-evolving reaction (OER) in a basic electrolyte solution containing the Li-ion and hydrogen-evolving reaction (HER) in an acidic electrolyte solution. PMID:26804323

  8. Electronic coupling through natural amino acids

    NASA Astrophysics Data System (ADS)

    Berstis, Laura; Beckham, Gregg T.; Crowley, Michael F.

    2015-12-01

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green's function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design.

  9. Electronic coupling through natural amino acids

    SciTech Connect

    Berstis, Laura; Beckham, Gregg T. E-mail: gregg.beckham@nrel.gov; Crowley, Michael F. E-mail: gregg.beckham@nrel.gov

    2015-12-14

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green’s function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design.

  10. Nature in the Classroom: Acid Rain.

    ERIC Educational Resources Information Center

    Doyle, Charles

    1982-01-01

    As a lesson topic, acid rain is defined, its chemistry given, and its development since the 1950s described. The worldwide effects of acid rain are discussed along with the available technology for controlling the problem. (CM)

  11. Esterification by the Plasma Acidic Water: Novel Application of Plasma Acid

    NASA Astrophysics Data System (ADS)

    Gu, Ling

    2014-03-01

    This work explores the possibility of plasma acid as acid catalyst in organic reactions. Plasma acidic water was prepared by dielectric barrier discharge and used to catalyze esterification of n-heptanioc acid with ethanol. It is found that the plasma acidic water has a stable and better performance than sulfuric acid, meaning that it is an excellent acid catalyst. The plasma acidic water would be a promising alternative for classic mineral acid as a more environment friendly acid.

  12. Permittivity of naphthenic acid-water mixture.

    PubMed

    Mishra, Sabyasachi; Meda, Venkatesh; Dalai, Ajay

    2007-01-01

    Naphthenic acid (NA) is predominantly a mono-carboxylic acid obtained as a by-product of petroleum refining with variable composition and ingredients. It is reported that water affected by processes in the petroleum industries generally contains 40-120 mg IL of naphthenic acid which is considered to be in the range of toxicity to human consumption [Clemente et. al, 2005; McMartin, 2003]. This contaminated water needs treatment before its use as drinking water by remote communities. Recent literature suggests that NAs could be separated from diesel fuel using microwave radiation [Lingzhao et. al, 2004]. Removal of naphthenic acid from vacuum cut #1 distillate oil of Daqing using microwaves has also been reported by Huang et. al [2006]. The microwave treatment can be applied to drinking water containing small concentrations of naphthenic acid. In this case permittivity information is useful in designing a microwave applicator and modeling studies. Permittivity measurements were done using a HP 8510 Vector Network Analyzer and coaxial probe reflection method to study the dielectric properties of naphthenic acid in water. The effects of process variables such as frequency, concentration and temperature on dielectric properties were determined. PMID:18161419

  13. Permittivity of naphthenic acid-water mixture.

    PubMed

    Mishra, Sabyasachi; Meda, Venkatesh; Dalai, Ajay

    2007-01-01

    Naphthenic acid (NA) is predominantly a mono-carboxylic acid obtained as a by-product of petroleum refining with variable composition and ingredients. It is reported that water affected by processes in the petroleum industries generally contains 40-120 mg IL of naphthenic acid which is considered to be in the range of toxicity to human consumption [Clemente et. al, 2005; McMartin, 2003]. This contaminated water needs treatment before its use as drinking water by remote communities. Recent literature suggests that NAs could be separated from diesel fuel using microwave radiation [Lingzhao et. al, 2004]. Removal of naphthenic acid from vacuum cut #1 distillate oil of Daqing using microwaves has also been reported by Huang et. al [2006]. The microwave treatment can be applied to drinking water containing small concentrations of naphthenic acid. In this case permittivity information is useful in designing a microwave applicator and modeling studies. Permittivity measurements were done using a HP 8510 Vector Network Analyzer and coaxial probe reflection method to study the dielectric properties of naphthenic acid in water. The effects of process variables such as frequency, concentration and temperature on dielectric properties were determined.

  14. Natural water purification and water management by artificial groundwater recharge

    PubMed Central

    Balke, Klaus-Dieter; Zhu, Yan

    2008-01-01

    Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and river water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant purification and/or the use of subsurface dams and artificial aquifers, is especially advantageous in areas where layers of gravel and sand exist below the earth’s surface. Artificial infiltration of surface water into the uppermost aquifer has qualitative and quantitative advantages. The contamination of infiltrated river water will be reduced by natural attenuation. Clay minerals, iron hydroxide and humic matter as well as microorganisms located in the subsurface have high decontamination capacities. By this, a final water treatment, if necessary, becomes much easier and cheaper. The quantitative effect concerns the seasonally changing river discharge that influences the possibility of water extraction for drinking water purposes. Such changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the river discharge and the water need. This method enables a continuous water supply over the whole year. Generally, artificially recharged groundwater is better protected against pollution than surface water, and the delimitation of water protection zones makes it even more save. PMID:18357624

  15. Natural water purification and water management by artificial groundwater recharge.

    PubMed

    Balke, Klaus-Dieter; Zhu, Yan

    2008-03-01

    Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and river water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant purification and/or the use of subsurface dams and artificial aquifers, is especially advantageous in areas where layers of gravel and sand exist below the earth's surface. Artificial infiltration of surface water into the uppermost aquifer has qualitative and quantitative advantages. The contamination of infiltrated river water will be reduced by natural attenuation. Clay minerals, iron hydroxide and humic matter as well as microorganisms located in the subsurface have high decontamination capacities. By this, a final water treatment, if necessary, becomes much easier and cheaper. The quantitative effect concerns the seasonally changing river discharge that influences the possibility of water extraction for drinking water purposes. Such changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the river discharge and the water need. This method enables a continuous water supply over the whole year. Generally, artificially recharged groundwater is better protected against pollution than surface water, and the delimitation of water protection zones makes it even more save.

  16. Bacterial Cyanuric Acid Hydrolase for Water Treatment

    PubMed Central

    Yeom, Sujin; Mutlu, Baris R.; Aksan, Alptekin

    2015-01-01

    Di- and trichloroisocyanuric acids are widely used as water disinfection agents, but cyanuric acid accumulates with repeated additions and must be removed to maintain free hypochlorite for disinfection. This study describes the development of methods for using a cyanuric acid-degrading enzyme contained within nonliving cells that were encapsulated within a porous silica matrix. Initially, three different bacterial cyanuric acid hydrolases were compared: TrzD from Acidovorax citrulli strain 12227, AtzD from Pseudomonas sp. strain ADP, and CAH from Moorella thermoacetica ATCC 39073. Each enzyme was expressed recombinantly in Escherichia coli and tested for cyanuric acid hydrolase activity using freely suspended or encapsulated cell formats. Cyanuric acid hydrolase activities differed by only a 2-fold range when comparing across the different enzymes with a given format. A practical water filtration system is most likely to be used with nonviable cells, and all cells were rendered nonviable by heat treatment at 70°C for 1 h. Only the CAH enzyme from the thermophile M. thermoacetica retained significant activity under those conditions, and so it was tested in a flowthrough system simulating a bioreactive pool filter. Starting with a cyanuric acid concentration of 10,000 μM, more than 70% of the cyanuric acid was degraded in 24 h, it was completely removed in 72 h, and a respike of 10,000 μM cyanuric acid a week later showed identical biodegradation kinetics. An experiment conducted with water obtained from municipal swimming pools showed the efficacy of the process, although cyanuric acid degradation rates decreased by 50% in the presence of 4.5 ppm hypochlorite. In total, these experiments demonstrated significant robustness of cyanuric acid hydrolase and the silica bead materials in remediation. PMID:26187963

  17. Bacterial Cyanuric Acid Hydrolase for Water Treatment.

    PubMed

    Yeom, Sujin; Mutlu, Baris R; Aksan, Alptekin; Wackett, Lawrence P

    2015-10-01

    Di- and trichloroisocyanuric acids are widely used as water disinfection agents, but cyanuric acid accumulates with repeated additions and must be removed to maintain free hypochlorite for disinfection. This study describes the development of methods for using a cyanuric acid-degrading enzyme contained within nonliving cells that were encapsulated within a porous silica matrix. Initially, three different bacterial cyanuric acid hydrolases were compared: TrzD from Acidovorax citrulli strain 12227, AtzD from Pseudomonas sp. strain ADP, and CAH from Moorella thermoacetica ATCC 39073. Each enzyme was expressed recombinantly in Escherichia coli and tested for cyanuric acid hydrolase activity using freely suspended or encapsulated cell formats. Cyanuric acid hydrolase activities differed by only a 2-fold range when comparing across the different enzymes with a given format. A practical water filtration system is most likely to be used with nonviable cells, and all cells were rendered nonviable by heat treatment at 70°C for 1 h. Only the CAH enzyme from the thermophile M. thermoacetica retained significant activity under those conditions, and so it was tested in a flowthrough system simulating a bioreactive pool filter. Starting with a cyanuric acid concentration of 10,000 μM, more than 70% of the cyanuric acid was degraded in 24 h, it was completely removed in 72 h, and a respike of 10,000 μM cyanuric acid a week later showed identical biodegradation kinetics. An experiment conducted with water obtained from municipal swimming pools showed the efficacy of the process, although cyanuric acid degradation rates decreased by 50% in the presence of 4.5 ppm hypochlorite. In total, these experiments demonstrated significant robustness of cyanuric acid hydrolase and the silica bead materials in remediation. PMID:26187963

  18. Bacterial Cyanuric Acid Hydrolase for Water Treatment.

    PubMed

    Yeom, Sujin; Mutlu, Baris R; Aksan, Alptekin; Wackett, Lawrence P

    2015-10-01

    Di- and trichloroisocyanuric acids are widely used as water disinfection agents, but cyanuric acid accumulates with repeated additions and must be removed to maintain free hypochlorite for disinfection. This study describes the development of methods for using a cyanuric acid-degrading enzyme contained within nonliving cells that were encapsulated within a porous silica matrix. Initially, three different bacterial cyanuric acid hydrolases were compared: TrzD from Acidovorax citrulli strain 12227, AtzD from Pseudomonas sp. strain ADP, and CAH from Moorella thermoacetica ATCC 39073. Each enzyme was expressed recombinantly in Escherichia coli and tested for cyanuric acid hydrolase activity using freely suspended or encapsulated cell formats. Cyanuric acid hydrolase activities differed by only a 2-fold range when comparing across the different enzymes with a given format. A practical water filtration system is most likely to be used with nonviable cells, and all cells were rendered nonviable by heat treatment at 70°C for 1 h. Only the CAH enzyme from the thermophile M. thermoacetica retained significant activity under those conditions, and so it was tested in a flowthrough system simulating a bioreactive pool filter. Starting with a cyanuric acid concentration of 10,000 μM, more than 70% of the cyanuric acid was degraded in 24 h, it was completely removed in 72 h, and a respike of 10,000 μM cyanuric acid a week later showed identical biodegradation kinetics. An experiment conducted with water obtained from municipal swimming pools showed the efficacy of the process, although cyanuric acid degradation rates decreased by 50% in the presence of 4.5 ppm hypochlorite. In total, these experiments demonstrated significant robustness of cyanuric acid hydrolase and the silica bead materials in remediation.

  19. Solar Hot Water Heating by Natural Convection.

    ERIC Educational Resources Information Center

    Noble, Richard D.

    1983-01-01

    Presents an undergraduate laboratory experiment in which a solar collector is used to heat water for domestic use. The working fluid is moved by natural convection so no pumps are required. Experimental apparatus is simple in design and operation so that data can be collected quickly and easily. (Author/JN)

  20. Reclamation of acid waters using sewage sludge.

    PubMed

    Davison, W; Reynolds, C S; Tipping, E; Needham, R F

    1989-01-01

    An exhausted sand quarry which had filled with acid water (pH 3) from the oxidation of pyrite was treated with calcium hydroxide to neutralize the water (pH 8), and sewage sludge to prevent further ingress of acid. The water remained neutral for 2 years, an appreciable quantity of base being generated by the reduction of sulphate to sulphide in the anoxic sediment formed by the sewage sludge. After this time the water reverted to acid conditions, chiefly because the lake was too shallow to retain the sewage sludge over a sufficiently large area of its bed. Incubation experiments showed that the sewage sludge had a large capacity for sulphate reduction, which was equally efficient in acid or neutral waters and that the areal rate of consumption was sufficiently fast to neutralize all incoming acid, if at least 50% of the lake bed was covered with sludge. Throughout the course of the field investigations there was no foul smell and the lake was quickly colonized by phytoplankton, macrophytes and insects. Although nutrients associated with the sewage sludge stimulated photosynthesis and so caused the generation of additional organic matter, they were exhausted within two years. To ensure permanent reclamation, phosphate fertilizer could be added once the initial supply has been consumed. Neutralization removed trace metals from the system, presumably due to formation of insoluble oxyhydroxide and carbonates. The solubility of aluminium was apparently controlled by a basic aluminium sulphate (jurbanite).

  1. Natural toxins that affect plant amino acid metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A diverse range of natural compounds interfere with the synthesis and other aspects of amino acid metabolism. Some are amino acid analogues, but most are not. This review covers a number of specific natural phytotoxic compounds by molecular target site. Inhibition of glutamine synthetase is of part...

  2. Naturally occurring fatty acids: source, chemistry and uses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural occurring fatty acids are a large and complex class of compounds found in plants and animals. Fatty acids are abundant and of interest because of their renewability, biodegradability, biocompatibility, low cost, and fascinating chemistry. Of the many fatty acids, only 20-25 of them are widel...

  3. Acidities of Water and Methanol in Aqueous Solution and DMSO

    ERIC Educational Resources Information Center

    Gao, Daqing

    2009-01-01

    The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

  4. Spectra of particulate backscattering in natural waters.

    PubMed

    Gordon, Howard R; Lewis, Marlon R; McLean, Scott D; Twardowski, Michael S; Freeman, Scott A; Voss, Kenneth J; Boynton, G Chris

    2009-08-31

    Hyperspectral profiles of downwelling irradiance and upwelling radiance in natural waters (oligotrophic and mesotrophic) are combined with inverse radiative transfer to obtain high resolution spectra of the absorption coefficient (a) and the backscattering coefficient (b(b)) of the water and its constituents. The absorption coefficient at the mesotrophic station clearly shows spectral absorption features attributable to several phytoplankton pigments (Chlorophyll a, b, c, and Carotenoids). The backscattering shows only weak spectral features and can be well represented by a power-law variation with wavelength (lambda): b(b) approximately lambda(-n), where n is a constant between 0.4 and 1.0. However, the weak spectral features in b(b)b suggest that it is depressed in spectral regions of strong particle absorption. The applicability of the present inverse radiative transfer algorithm, which omits the influence of Raman scattering, is limited to lambda < 490 nm in oligotrophic waters and lambda < 575 nm in mesotrophic waters. PMID:19724619

  5. Spectra of Particulate Backscattering in Natural Waters

    NASA Technical Reports Server (NTRS)

    Gordon, Howard, R.; Lewis, Marlon R.; McLean, Scott D.; Twardowski, Michael S.; Freeman, Scott A.; Voss, Kenneth J.; Boynton, Chris G.

    2009-01-01

    Hyperspectral profiles of downwelling irradiance and upwelling radiance in natural waters (oligotrophic and mesotrophic) are combined with inverse radiative transfer to obtain high resolution spectra of the absorption coefficient (a) and the backscattering coefficient (bb) of the water and its constituents. The absorption coefficient at the mesotrophic station clearly shows spectral absorption features attributable to several phytoplankton pigments (Chlorophyll a, b, c, and Carotenoids). The backscattering shows only weak spectral features and can be well represented by a power-law variation with wavelength (lambda): b(sub b) approx. Lambda(sup -n), where n is a constant between 0.4 and 1.0. However, the weak spectral features in b(sub b), suggest that it is depressed in spectral regions of strong particle absorption. The applicability of the present inverse radiative transfer algorithm, which omits the influence of Raman scattering, is limited to lambda < 490 nm in oligotrophic waters and lambda < 575 nm in mesotrophic waters.

  6. Acid mine water aeration and treatment system

    DOEpatents

    Ackman, Terry E.; Place, John M.

    1987-01-01

    An in-line system is provided for treating acid mine drainage which basically comprises the combination of a jet pump (or pumps) and a static mixer. The jet pump entrains air into the acid waste water using a Venturi effect so as to provide aeration of the waste water while further aeration is provided by the helical vanes of the static mixer. A neutralizing agent is injected into the suction chamber of the jet pump and the static mixer is formed by plural sections offset by 90 degrees.

  7. Absorption coefficient instrument for turbid natural waters

    NASA Technical Reports Server (NTRS)

    Friedman, E.; Cherdak, A.; Poole, L.; Houghton, W.

    1980-01-01

    The paper presents an instrument that directly measures multispectral absorption coefficient of turbid natural water. Attention is given to the design, which is shown to incorporate methods for the compensation of variation in the internal light source intensity, correction of the spectrally dependent nature of the optical elements, and correction for variation in the background light level. In addition, when used in conjunction with a spectrally matched total attenuation instrument, the spectrally dependent scattering coefficient can also be derived. Finally, it is reported that systematic errors associated with multiple scattering have been estimated using Monte Carlo techniques.

  8. Determination of benzoic acid, chlorobenzoic acids and chlorendic acid in water

    SciTech Connect

    Dietz, E.A.; Cortellucci, N.J.; Singley, K.F. )

    1993-01-01

    To characterize and conduct treatment studies of a landfill leachate an analysis procedure was required to determine concentrations of benzoic acid, the three isomers of chlorobenzoic acid and chlorendic acid. The title compounds were isolated from acidified (pH 1) water by extraction with methyl t-butyl ether. Analytes were concentrated by back-extracting the ether with 0.1 N sodium hydroxide which was separated and acidified. This solution was analyzed by C[sub 18] reversed-phase HPLC with water/acetonitrile/acetic acid eluent and UV detection at 222 nm. The method has detection limits of 200 [mu]g/L for chlorendic acid and 100 [mu]g/L for benzoic acid and each isomer of chlorobenzoic acid. Validation studies with water which was fortified with the analytes at concentrations ranging from one to ten times detection limits resulted in average recoveries of >95%.

  9. Microbiological safety of natural mineral water.

    PubMed

    Leclerc, Henri; Moreau, Annick

    2002-06-01

    Natural mineral water originates from groundwater, an oligotrophic ecosystem where the level of organic matter is low and of a very limited bioavailability. The bacterial populations that evolve in these ecosystems are heterotrophic and in starvation-survival state resulting from an insufficient amount of nutrients; for this reason they enter a viable but non-culturable state. After bottling, the number of viable counts increases rapidly, attaining 10(4)-10(5) colony-forming units ml(-1) within 3-7 days. These bacterial communities, identified by culture or with specific probes, are primarily aerobic, saprophytic, Gram-negative rods. Groundwater sources for natural mineral waters are selected such that they are not vulnerable to fecal contamination. Ecological data, especially the diversity and physiological properties of bacterial communities, are essential together with epidemiological studies in order to perform a risk analysis for natural mineral waters. On a continuing basis, the management of microbial risks has to rely on assessment of the heterotrophic plate count and, more specially, on detection of marker organisms, i.e. the classic fecal contamination indicators that have to be absent, and vulnerability indicators for which the occurrence should be as low as possible. It is also recommended to search regularly, but not routinely, for viral and protozoan pathogens.

  10. Measurement of tritium in natural water

    NASA Astrophysics Data System (ADS)

    Li, Meifen

    1985-06-01

    A detergent-scintillation liquid mixture applied to measure low specific activity of tritium in natural water was studied. The DYS-1 low level liquid scintillation counter designed and manufactured by our institute was employed. In comparing the Triton X-100 scintillation liquid mixture with the dioxane-based-scintillation liquid, a better formula for Triton X-100 scintillation liquid mixture was determined, the mixture possesses the quality of high water content; high efficiency and low back-ground in measuring tritium in water. Chemiluminescence of the Triton X-100 scintillation liquid mixture can be totally de-excited in short time. It can be employed at ambient temperature 11 28°C. For 20ml sample in quartz vials, counting efficiency is 15% with a background 2.17 cpm, Y=31 TU (t=30 min).

  11. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, P.V.; Coleman, R.D.

    1996-10-08

    A water and UV light degradable copolymer is described made from monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene glycol, propylene glycol, P-dioxanone, 1,5 dioxepan-2-one, 1,4-oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2 by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  12. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, Patrick V.; Coleman, Robert D.

    1996-01-01

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene glycol, propylene glycol, P-dioxanone, 1,5 dioxepan-2-one, 1,4-oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2 by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  13. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, P.V.; Coleman, R.D.

    1994-11-01

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer were selected from the class consisting of ethylene and polyethylene glycols, propylene and polypropylene glycols, P-dioxanone, 1,5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide where the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures to an agricultural site is also disclosed.

  14. Water and UV degradable lactic acid polymers

    DOEpatents

    Bonsignore, Patrick V.; Coleman, Robert D.

    1994-01-01

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene and polyethylene glycols, propylene and polypropylene glycols, P-dioxanone, 1,5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  15. Water and UV degradable lactic acid polymers

    SciTech Connect

    Bonsignore, P.V.; Coleman, R.D.

    1990-06-26

    A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene and polyethylane glycols (PVB 6/22/90), propylene and and polypropylene (PVB 6/22/90) glycols, P-dioxanone, 1, 5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

  16. Extremely acid Permian lakes and ground waters in North America

    USGS Publications Warehouse

    Benison, K.C.; Goldstein, R.H.; Wopenka, B.; Burruss, R.C.; Pasteris, J.D.

    1998-01-01

    Evaporites hosted by red beds (red shales and sandstones), some 275-265 million years old, extend over a large area of the North American mid- continent. They were deposited in non-marine saline lakes, pans and mud- flats, settings that are typically assumed to have been alkaline. Here we use laser Raman microprobe analyses of fluid inclusions trapped in halites from these Permian deposits to argue for the existence of highly acidic (pH < 1) lakes and ground waters. These extremely acidic systems may have extended over an area of 200,000 km2. Modern analogues of such systems may be natural acid lake and groundwater systems (pH ~2-4) in southern Australia. Both the ancient and modern acid systems are characterized by closed drainage, arid climate, low acid-neutralizing capacity, and the oxidation of minerals such as pyrite to generate acidity. The discovery of widespread ancient acid lake and groundwater systems demands a re-evaluation of reconstructions of surface conditions of the past, and further investigations of the geochemistry and ecology of acid systems in general.

  17. Diverging effects of anthropogenic acidification and natural acidity on community structure in Swedish streams.

    PubMed

    Petrin, Zlatko; Laudon, Hjalmar; Malmqvist, Björn

    2008-05-15

    Anthropogenic acidification caused by aerial deposition of acidifying substances is known to have detrimental effects on freshwater biota, including reductions in species diversity and ecosystem functioning. However, such impairment is not found in systems acidified to a similar extent by natural processes. A proposed explanation for this difference is that freshwater organisms have had far more time to evolve and adapt to natural than anthropogenic acidification. Thus, where acidity is natural, adaptation may account for diverse and functional communities. Here, we investigated whether adaptations--that were previously implied to occur on small spatial scales--may explain the species richness patterns on a much larger geographical scale, apply to ecological functioning, and are relevant in Sweden, where natural acidity is geologically relatively recent. Therefore, we compared differences in species diversity and ecosystem process rates between 24 acidic and circumneutral streams in northern Sweden, where acidity is natural, and southern Sweden, where acidity is largely anthropogenic. In agreement with our predictions, the difference in macroinvertebrate species richness between acidic and circumneutral streams was threefold larger in the region where acidity was anthropogenic than where it was natural, albeit marginally non-significantly. In contrast, no such trend was found for the rates of decomposition by microbes and leaf-feeding macroinvertebrates, possibly due to functional redundancy. The structure of species assemblages differed between acidic and circumneutral sites and between the regions. Our results agree with the notion that freshwater biota are adapted to natural acidity, but competing explanations including other differences in water chemistry and differences in the biogeographical colonization histories may also account for part of the observed patterns. Since naturally acidic environments similar to those in northern Sweden are widespread, we

  18. Diverging effects of anthropogenic acidification and natural acidity on community structure in Swedish streams.

    PubMed

    Petrin, Zlatko; Laudon, Hjalmar; Malmqvist, Björn

    2008-05-15

    Anthropogenic acidification caused by aerial deposition of acidifying substances is known to have detrimental effects on freshwater biota, including reductions in species diversity and ecosystem functioning. However, such impairment is not found in systems acidified to a similar extent by natural processes. A proposed explanation for this difference is that freshwater organisms have had far more time to evolve and adapt to natural than anthropogenic acidification. Thus, where acidity is natural, adaptation may account for diverse and functional communities. Here, we investigated whether adaptations--that were previously implied to occur on small spatial scales--may explain the species richness patterns on a much larger geographical scale, apply to ecological functioning, and are relevant in Sweden, where natural acidity is geologically relatively recent. Therefore, we compared differences in species diversity and ecosystem process rates between 24 acidic and circumneutral streams in northern Sweden, where acidity is natural, and southern Sweden, where acidity is largely anthropogenic. In agreement with our predictions, the difference in macroinvertebrate species richness between acidic and circumneutral streams was threefold larger in the region where acidity was anthropogenic than where it was natural, albeit marginally non-significantly. In contrast, no such trend was found for the rates of decomposition by microbes and leaf-feeding macroinvertebrates, possibly due to functional redundancy. The structure of species assemblages differed between acidic and circumneutral sites and between the regions. Our results agree with the notion that freshwater biota are adapted to natural acidity, but competing explanations including other differences in water chemistry and differences in the biogeographical colonization histories may also account for part of the observed patterns. Since naturally acidic environments similar to those in northern Sweden are widespread, we

  19. Distillation of natural fatty acids and their chemical derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Well over 1,000 different fatty acids are known which are natural components of fats, oils (triacylglycerols), and other related compounds. These fatty acids can have different alkyl chain lengths, 0-6 carbon-carbon double bonds possessing cis- or trans-geometry, and can contain a variety of functio...

  20. Arsenic speciation in natural sulfidic geothermal waters

    NASA Astrophysics Data System (ADS)

    Keller, Nicole S.; Stefánsson, Andri; Sigfússon, Bergur

    2014-10-01

    The speciation of arsenic in natural sulfidic geothermal waters was studied using chemical analyses and thermodynamic aqueous speciation calculations. Samples were collected in three geothermal systems in Iceland, having contrasting H2S concentrations in the reservoir (high vs. low). The sampled waters contained 7-116 ppb As and <0.01-77.6 ppm H2S with pH of 8.56-9.60. The analytical setup used for the determination of arsenic species (Ion Chromatography-Hydride Generation Atomic Fluorescence Spectrometry, IC-HG-AFS) was field-deployed and the samples analyzed within ∼5 min of sampling in order to prevent changes upon storage, which were shown to be considerable regardless of the sample storage method used. Nine aqueous arsenic species were detected, among others arsenite (HnAsO3n-3), thioarsenite (HnAsS3n-3), arsenate (HnAsO4n-3), monothioarsenate (HnAsSO3n-3), dithioarsenate (HnAsS2O2n-3), trithioarsenate (HnAsS3O) and tetrathioarsenate (HnAsS4n-3). The results of the measured aqueous arsenic speciation in the natural geothermal waters and comparison with thermodynamic calculations reveal that the predominant factors determining the species distribution are sulfide concentration and pH. In alkaline waters with low sulfide concentrations the predominant species are AsIII oxyanions. This can be seen in samples from a liquid-only well, tapping water that is H2S-poor and free of oxygen. At intermediate sulfide concentration AsIII and AsV thio species become important and predominate at high sulfide concentration, as seen in two-phase well waters, which have high H2S concentrations in the reservoir. Upon oxidation, for instance due to mixing of the reservoir fluid with oxygenated water upon ascent to the surface, AsV oxyanions form, as well as AsV thio complexes if the sulfide concentration is intermediate to high. This oxidation process can be seen in samples from hot springs in the Geysir geothermal area. While the thermodynamic modeling allows for a first

  1. Humic acid adsorption and surface charge effects on schwertmannite and goethite in acid sulphate waters.

    PubMed

    Kumpulainen, Sirpa; von der Kammer, Frank; Hofmann, Thilo

    2008-04-01

    In acid conditions, as in acid mine drainage waters, iron oxide particles are positively charged, attracting negatively charged organic particles present in surrounding natural waters. Schwertmannite (Fe8O8(OH)6SO4) and goethite (alpha-FeOOH) are the most typical iron oxide minerals found in mine effluents. We studied schwertmannite formation in the presence of humic acid. Further, surface charge and adsorption of humic acid on synthetic schwertmannite and goethite surfaces in pH 2-9 and in humic acid concentrations of 0.1-100 mg/L C were examined. Schwertmannite did precipitate despite the presence of humic acid, although it contained more sulphate and had higher specific surface area than ordinary schwertmannite. Specific surface area weighted results showed that schwertmannite and goethite had similar humic acid adsorption capacities. Sulphate was released from schwertmannite surfaces with increasing pH, resulting in an increase in specific surface area. Presence of sulphate in solution decreased the surface charge of schwertmannite and goethite similarly, causing coagulation. In acid conditions (pH 2-3.5), according to the zeta potential, schwertmannite is expected to coagulate even in the presence of high concentrations of humic acid (< or = 100 mg/L C). However, at high humic acid concentrations (10-100 mg/L C) with moderate acid conditions (pH>3.5), both schwertmannite and goethite surfaces are strongly negatively charged (zeta potential < -30 mV) thus posing a risk for colloid stabilization and colloidal transport. PMID:18221768

  2. Thermodynamics of natural and industrial waters

    SciTech Connect

    Pitzer, K.S.

    1991-08-01

    The most effective general formulations of thermodynamic equations for multicomponent aqueous solutions are discussed with respect to various ranges of temperature, pressure and composition with emphasis on solutes important in natural or industrial waters. A familiar equation in molality and in excess Gibbs energy is very successful up to 300{degree}C and ionic strength 6 mol{center dot}kg{sup {minus}1}, and can often be extended to 350{degree}C or above at high pressure and in favorable cases to ionic strength 12 or even 20. Alternate methods valid to higher solute compositions, even to pure fused salts, are described. A more difficult situation arises near the critical point of water where the compressibility becomes infinite and a Helmholtz energy basis must be adopted. Existing equations for this range and still higher temperatures and pressures are considered and possible improvements discussed. 85 refs., 13 figs., 3 tabs.

  3. Solubility of magnesium carbonate in natural waters

    USGS Publications Warehouse

    Wells, R.C.

    1915-01-01

    (1) Under atmospheric conditions it appears possible to attain practically the same state in a solution saturated with MgCO33H2O, whether one starts with a solution containing an excess of magnesium bicarbonate or with the pure trihydrate and water, but the adjustment occurs very slowly. The solution finally contains 0.36 g. magnesium and 1.01 g. carbon dioxide per liter at 20??. (2) The solubility found for magnesite, however, is much smaller, viz., 0.02 g. magnesium and 0.07 g. carbon dioxide per liter. (3) Certain natural waters, freely exposed to the atmosphere, appear to be supersaturated with respect to magnesite but none approaches very closely to the point of saturation of the trihydrate MgCO3.3H2O.

  4. Artificial photosynthesis: understanding water splitting in nature

    PubMed Central

    Cox, Nicholas; Pantazis, Dimitrios A.; Neese, Frank; Lubitz, Wolfgang

    2015-01-01

    In the context of a global artificial photosynthesis (GAP) project, we review our current work on nature's water splitting catalyst. In a recent report (Cox et al. 2014 Science 345, 804–808 (doi:10.1126/science.1254910)), we showed that the catalyst—a Mn4O5Ca cofactor—converts into an ‘activated’ form immediately prior to the O–O bond formation step. This activated state, which represents an all MnIV complex, is similar to the structure observed by X-ray crystallography but requires the coordination of an additional water molecule. Such a structure locates two oxygens, both derived from water, in close proximity, which probably come together to form the product O2 molecule. We speculate that formation of the activated catalyst state requires inherent structural flexibility. These features represent new design criteria for the development of biomimetic and bioinspired model systems for water splitting catalysts using first-row transition metals with the aim of delivering globally deployable artificial photosynthesis technologies. PMID:26052426

  5. Treatment of Natural Peanut Butter with Phytic Acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut butter may be less allergenic if allergens in the butter exist as insoluble complexes that are not absorbed by the body. We determined that such complexes form in natural peanut butter that is treated with phytic acid. Commercial natural peanut butter (non-hydrogenated, creamy, oil-based, and...

  6. Acidic deposition and surface water chemistry

    NASA Astrophysics Data System (ADS)

    Church, M. R.

    A pair of back-to-back (morning and afternoon) hydrology sessions, held December 10, 1987, at the AGU Fall Meeting in San Francisco, Calif., covered “Predicting the Effects of Acidic Deposition on Surface Water Chemistry.” The combined sessions included four invited papers, 12 contributed papers, and a panel discussion at its conclusion. The gathering dealt with questions on a variety of aspects of modeling the effects of acidic deposition on surface water chemistry.Contributed papers included discussions on the representation of processes in models as well as limiting assumptions in model application (V. S. Tripathi et al., Oak Ridge National Laboratory, Oak Ridge, Tenn., and E. C. Krug, Illinois State Water Survey, Champaign), along with problems in estimating depositional inputs to catchments and thus inputs to be used in the simulation of catchment response (M. M. Reddy et al., U.S. Geological Survey, Lakewood, Colo.; and E. A. McBean, University of Waterloo, Waterloo, Canada). L. A. Baker et al. (University of Minnesota, Minneapolis) dealt with the problem of modeling seepage lake systems, an exceedingly important portion of the aquatic resources in Florida and parts of the upper U.S. Midwest. J. A. Hau and Y. Eckstein (Kent State University, Kent, Ohio) considered equilibrium modeling of two northern Ohio watersheds that receive very different loads of acidic deposition but are highly similar in other respects.

  7. Natural cinnamic acids, synthetic derivatives and hybrids with antimicrobial activity.

    PubMed

    Guzman, Juan David

    2014-11-25

    Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC) of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships.

  8. Fatty acid composition of water buffalo meat.

    PubMed

    Sharma, N; Gandemer, G; Goutefongea, R; Kowale, B N

    1986-01-01

    The fatty acid composition of intramuscular lipids of Longissimus dorsi (LD), Psoas major (PM), Biceps femoris (BF), Semitendinosus (ST) muscles and liver of water buffalo male calves was determined by capillary gas-liquid chromatography. The content of total lipids in the LD muscle was found to be maximum, followed by PM, BF and ST in decreasing order (1·03, 0·99, 0·66 and 0·55g/100g of fresh muscle). Liver contained 2·65 g of total lipids per 100 g of fresh tissue. Following the anatomical location, intramuscular lipids contained 44-55% of saturated fatty acids, of which the major components were stearic and palmitic acids. Mono-unsaturated fatty acids (31-40%) composed mainly oleic acid (90%). The PUFA contents in PM, LD, ST and BF were, respectively, 11%, 12%, 13% and 16%. The predominant PUFA were linoleic (66%) and arachidonic (25%). The significance of difference of PUFA content between muscles is discussed. Liver contained 48%, 27% and 22% saturated, monosaturated and PUFA, respectively. The PUFA in liver were linoleic (36%), C20 (47%) and C22 (9%).

  9. Water-wire catalysis in photoinduced acid-base reactions.

    PubMed

    Kwon, Oh-Hoon; Mohammed, Omar F

    2012-07-01

    The pronounced ability of water to form a hyperdense hydrogen (H)-bond network among itself is at the heart of its exceptional properties. Due to the unique H-bonding capability and amphoteric nature, water is not only a passive medium, but also behaves as an active participant in many chemical and biological reactions. Here, we reveal the catalytic role of a short water wire, composed of two (or three) water molecules, in model aqueous acid-base reactions synthesizing 7-hydroxyquinoline derivatives. Utilizing femtosecond-resolved fluorescence spectroscopy, we tracked the trajectories of excited-state proton transfer and discovered that proton hopping along the water wire accomplishes the reaction more efficiently compared to the transfer occurring with bulk water clusters. Our finding suggests that the directionality of the proton movements along the charge-gradient H-bond network may be a key element for long-distance proton translocation in biological systems, as the H-bond networks wiring acidic and basic sites distal to each other can provide a shortcut for a proton in searching a global minimum on a complex energy landscape to its destination.

  10. Factors controlling water movement in acid spoils

    SciTech Connect

    Evangelou, V.P.; Grove, J.H.; Phillips, R.E.

    1982-12-01

    The rate of water movement through toxic spoils plays a major role in reclamation. The toxic chemical constituents found in spoils need to be leached beyond the six inch depth (the usual depth of lime incorporation) since they can easily move upward during periods of high evapotranspiration. The rate of water infiltration plays a role in effective utilization of rain water, and conversely, the amount of surface runoff dictates the degree of surface erosion. Underground water quality may be affected by rates of water movement through a toxic spoil zone. Factors that control water movement through acid spoils were investigated through the use of a column one meter long and 8.0 cm in internal diameter. The maximum hydraulic conductivity was observed in the upper portion of the column where minimum salt buildup occurred. The hydraulic conductivity in this region was 0.5 cm/hr. In the middle portion of the column where a salty (14.0 mmhos/cm) solution was encountered, the hydraulic conductivity was 0.08 cm/hr. In the lower portion of the column where the maximum salt buildup took place (16.8 mmhos/cm), the hydraulic conductivity was found to be 0.03 cm/hr. Similar results were obtained with a small column experiment using calcite and dolomite as different lime sources. The hydraulic conductivity in the dolomitic small column remained relatively unchanged with time and salt depletion.

  11. Chlorination of organophosphorus pesticides in natural waters.

    PubMed

    Acero, Juan L; Benítez, F Javier; Real, Francisco J; González, Manuel

    2008-05-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 degrees C and pH 7 were determined to be 110.9, 0.004 and 191.6 M(-1) s(-1) for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L(-1) was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety.

  12. Removal of heavy metals from mine waters by natural zeolites

    SciTech Connect

    Ulla Wingenfelder; Carsten Hansen; Gerhard Furrer; Rainer Schulin

    2005-06-15

    The study investigated the removal of Fe, Pb, Cd, and Zn from synthetic mine waters by a natural zeolite. The emphasis was given to the zeolite's behavior toward a few cations in competition with each other. Pb was removed efficiently from neutral as well as from acidic solutions, whereas the uptake of Zn and Cd decreased with low pH and high iron concentrations. With increasing Ca concentrations in solution, elimination of Zn and Cd became poorer while removal of Pb remained virtually unchanged. The zeolite was stable in acidic solutions. Disintegration was only observed below pH 2.0. Forward- and back-titration of synthetic acidic mine water were carried out in the presence and absence of zeolite to simulate the effects of a pH increase by addition of neutralizing agents and a re-acidification which can be caused by subsequent mixing with acidic water. The pH increase during neutralization causes precipitation of hydrous ferric oxides and decreased dissolved metal concentrations. Zeolite addition further diminished Pb concentrations but did not have an effect on Zn and Cd concentrations in solution. During re-acidification of the solution, remobilization of Pb was weaker in the presence than in the absence of zeolite. No substantial differences were observed for Fe, Cd, and Zn immobilization. The immobilization of the metals during pH increase and the subsequent remobilization caused by re-acidification can be well described by a geochemical equilibrium speciation model that accounts for metal complexation at hydrous ferric oxides, for ion exchange on the zeolite surfaces, as well as for dissolution and precipitation processes. 42 refs., 5 figs., 3 tabs.

  13. State of radionuclides in natural waters

    SciTech Connect

    Kulmatov, R.A.; Rakhmatov, U.; Kist, A.A.; Volkov, A.A.

    1987-03-01

    This work is devoted to a study of the kinetics of attainment of equilibrium between various forms of the radionuclide mercury-203 and to an evaluation of the part played by isotope exchange in this process. The radionuclide mercury-203 was added without a carrier to natural waters of the Syr-Dar'ya and Amu-Dar'ya Rivers and the Aral Sea in the cationic form (3). In order to determine the time of attainment of equilibrium between the forms of the radionuclide mercury-203 and the stable nuclide analogs, they used the methods of sorption on L-36 glass, AV-17 anion-exchanger, KU-2 cation-exchanger, extraction with chloroform plus isobutyl alcohol, and filtration.

  14. PHOTOCHEICAL PRODUCTION OF HYDROXYL RADICAL IN NATURAL WATER - THE ROLE OF IRON AND DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    Photochemical hydroxyl radical (OH) production was measured in several natural waters to investigate the importance of colored dissolved organic matter (CDOM) and iron-CDOM complexes as sources of OH. High rates of OH photoproduction in highly colored, iron-rich, acidic waters a...

  15. Anthropogenic and natural sources of acidity and metals and their influence on the structure of stream food webs.

    PubMed

    Hogsden, Kristy L; Harding, Jon S

    2012-03-01

    We compared food web structure in 20 streams with either anthropogenic or natural sources of acidity and metals or circumneutral water chemistry in New Zealand. Community and diet analysis indicated that mining streams receiving anthropogenic inputs of acidic and metal-rich drainage had much simpler food webs (fewer species, shorter food chains, less links) than those in naturally acidic, naturally high metal, and circumneutral streams. Food webs of naturally high metal streams were structurally similar to those in mining streams, lacking fish predators and having few species. Whereas, webs in naturally acidic streams differed very little from those in circumneutral streams due to strong similarities in community composition and diets of secondary and top consumers. The combined negative effects of acidity and metals on stream food webs are clear. However, elevated metal concentrations, regardless of source, appear to play a more important role than acidity in driving food web structure. PMID:22088498

  16. DETOXIFICATION OF OUTFALL WATER USING NATURAL ORGANIC MATTER

    SciTech Connect

    Halverson, N.; Looney, B.; Millings, M.; Nichols, R.; Noonkester, J.; Payne, B.

    2010-07-13

    To protect stream organisms in an ephemeral stream at the Savannah River Site, a proposed National Pollutant Discharge Elimination System (NPDES) permit reduced the copper limit from 25 {micro}g/l to 6 {micro}g/l at Outfall H-12. Efforts to reduce copper in the wastewater and stormwater draining to this outfall did not succeed in bringing copper levels below this limit. Numerous treatment methods were considered, including traditional methods such as ion exchange and natural treatment alternatives such as constructed wetlands and peat beds, all of which act to remove copper. However, the very low target metal concentration and highly variable outfall conditions presented a significant challenge for these treatment technologies. In addition, costs and energy use for most of these alternatives were high and secondary wastes would be generated. The Savannah River National Laboratory developed an entirely new 'detoxification' approach to treat the outfall water. This simple, lower-cost detoxification system amends outfall water with natural organic matter to bind up to 25 {micro}g/l copper rather than remove it, thereby mitigating its toxicity and protecting the sensitive species in the ecosystem. The amendments are OMRI (Organic Materials Review Institute) certified commercial products that are naturally rich in humic acids and are commonly used in organic farming.

  17. Acid mine water treatment using engineered wetlands

    NASA Astrophysics Data System (ADS)

    Kleinmann, Robert L. P.

    1990-03-01

    During the last two decades, the United States mining industry has greatly increased the amount it spends on pollution control. The application of biotechnology to mine water can reduce the industry's water treatment costs (estimated at over a million dollars a day) and improve water quality in streams and rivers adversely affected by acidic mine water draining from abandoned mines. Biological treatment of mine waste water is typically conducted in a series of small excavated ponds that resemble, in a superficial way, a small marsh area. The ponds are engineered to first facilitate bacterial oxidation of iron; ideally, the water then flows through a composted organic substrate that supports a population of sulfate-reducing bacteria. The latter process raises the pH. During the past four years, over 400 wetland water treatment systems have been built on mined lands as a result of research by the U.S. Bureau of Mines. In general, mine operators find that the wetlands reduce chemical treatment costs enough to repay the cost of wetland construction in less than a year. Actual rates of iron removal at field sites have been used to develop empirical sizing criteria based on iron loading and pH. If the pH is 6 or above, the wetland area (m2) required is equivalent to the iron load (grams/day) divided by 10. Theis requirement doubles at a pH of 4 to 5. At a pH below 4, the iron load (grams/day) should be divided by 2 to estimate the area required (m2).

  18. Red cochineal dye (carminic Acid): its role in nature.

    PubMed

    Eisner, T; Nowicki, S; Goetz, M; Meinwald, J

    1980-05-30

    Carminic acid, the well-known red dyestuff from cochineal insects (Dactylopius spp.), is a potent feeding deterrent to ants. This deterrency may be indicative of the natural function of the compound, which may have evolved in cochineals as a chemical weapon against predation. The behavior of an unusual predator is described-the carnivorous caterpillar of a pyralid moth (Laetilia coccidivora)-which is undeterred by carminic acid and feeds on cochineals. The animal has the remarkable habit of utilizing the ingested carminic acid for defensive purposes of its own. PMID:17779027

  19. Serum concentration of sialic acids in naturally occurring ovine babesiosis.

    PubMed

    Esmaeilnejad, Bijan; Tavassoli, Mousa; Asri-Rezaei, Siamak; Dalir-Naghadeh, Bahram; Abtahi Froushani, Seyyed Meysam; Arjmand, Jafar; Golabi, Mostafa

    2014-10-01

    This study is designated to assess the effect of the severity of Babesia ovis infection on sialic acid concentration in blood sera in naturally infected sheep. Infected animals (diseased group) comprised 38 Iranian fat-tailed sheep, about 1-3 years old, naturally infected with B. ovis, divided into four subgroups with respect to parasitemia rates (low 0.1-0.3 %, moderate 0.4-0.9 %, high 1-2.5 %, and very high >2.5 %). The parasitological diagnosis was confirmed using PCR analysis. As a control group, ten clinically healthy sheep reared under the same management and environmental conditions were also sampled. Hematological parameters and the concentrations of total sialic acid (TSA), lipid-bound sialic acid (LBSA), and protein-bound sialic acid (PBSA) were measured in both groups. Compared to controls, sialic acid concentrations showed significant increase (p < 0.05) in infected sheep. Parasitemia rate was positively correlated with sialic acid concentrations. This study demonstrated that B. ovis infection induced marked and persistent elevations of serum sialic acid concentrations. It seems that increase of serum sialic acid concentrations during parasitemia alter receptor-ligand interactions, which are known to play important role in immune response. Furthermore, sialic acid would indirectly inhibit the action of leukocytes and consequently promote the evasion of the immune response and persistence of the parasite in the host. This factor could influence the parasite-host cell adhesion, but further detailed biochemical investigations are needed to precisely explain the exact role of sialic acid in invasion process of the parasite to the host cells.

  20. Nature and chlorine reactivity of organic constituents from reclaimed water in groundwater, Los Angeles County, California

    USGS Publications Warehouse

    Leenheer, J.A.; Rostad, C.E.; Barber, L.B.; Schroeder, R.A.; Anders, R.; Davisson, M.L.

    2001-01-01

    The nature and chlorine reactivity of organic constituents in reclaimed water (tertiary-treated municipal wastewater) before, during, and after recharge into groundwater at the Montebello Forebay in Los Angeles County, CA, was the focus of this study. Dissolved organic matter (DOM) in reclaimed water from this site is primarily a mixture of aromatic sulfonates from anionic surfactant degradation, N-acetyl amino sugars and proteins from bacterial activity, and natural fulvic acid, whereas DOM from native groundwaters in the aquifer to which reclaimed water was recharged consists of natural fulvic acids. The hydrophilic neutral N-acetyl amino sugars that constitute 40% of the DOM in reclaimed water are removed during the first 3 m of vertical infiltration in the recharge basin. Groundwater age dating with 3H and 3He isotopes, and determinations of organic and inorganic C isotopes, enabled clear differentiation of recent recharged water from older native groundwater. Phenol structures in natural fulvic acids in DOM isolated from groundwater produced significant trihalomethanes (THM) and total organic halogen (TOX) yields upon chlorination, and these structures also were responsible for the enhanced SUVA and specific fluorescence characteristics relative to DOM in reclaimed water. Aromatic sulfonates and fulvic acids in reclaimed water DOM produced minimal THM and TOX yields.

  1. Acid gas extraction of pyridine from water

    SciTech Connect

    Laitinen, A.; Kaunisto, J.

    2000-01-01

    Pyridine was extracted from aqueous solutions initially containing 5 or 15 wt % pyridine by using liquid or supercritical carbon dioxide at 10 MPa as a solvent in a mechanically agitated countercurrent extraction column. The lowest pyridine concentration in the raffinate was 0.06 wt %, whereas the pyridine concentration in the extract was 86--94 wt %. From the initial amount of pyridine, 96--99% was transferred from the feed stream to the extract by using relatively small solvent-to-feed ratios of 2.8--4.6 (kg of solvent/kg of feed). The measured distribution coefficients for the water/pyridine/carbon dioxide system ranged from 0.3 to 1 (weight units), depending on the initial pyridine concentration in water. Carbon dioxide is a particularly suitable solvent for the extraction of pyridine from concentrated aqueous solutions. The efficiency may be the result of an acid-base interaction between weakly basic pyridine solute and weakly acidic carbon dioxide solvent in an aqueous environment.

  2. Effects of combined heat and acetic acid on natural microflora reduction on cantaloupe melons.

    PubMed

    Fouladkhah, Aliyar; Avens, John S

    2010-05-01

    Produce is an important source of nutrients and phytochemicals, which is important in a healthy diet. However, perishable fresh produce has caused recent outbreaks of foodborne diseases. High level of nutrients and water activity, direct contact with soil, and lack of thermal procedures during primary processing make fresh produce a potential food safety hazard. Fruits and vegetables with rough surfaces can harbor microorganisms and support their multiplication, increasing the risk of this hazard. This study evaluated the effects of extreme thermal processes combined with acetic acid on natural microflora reduction on cantaloupe melons. Melons from a local supermarket were assigned into five treatment groups: control, water at 25 degrees C, water at 95 degrees C, 5% acetic acid at 25 degrees C, and 5% acetic acid at 95 degrees C. Four skin samples were obtained from each melon, separately stomached for 2 min with 0.1% peptone water, and serially diluted. Aerobic plate counts (APC) of dilutions were determined. Statistical analysis (least significant difference-based analysis of variance) showed that there were no significant (P > 0.05) differences in APC among control, water at 25 degrees C, and 5% acetic acid at 25 degrees C. Thermal treatments with water at 95 degrees C, and 5% acetic acid at 95 degrees C, were both significantly (P < 0.05) more effective in APC reduction than were nonthermal treatments, but were not significantly different from each other. Results indicated that a thermal water immersion intervention in primary processing of fresh melons can result in a 3-log reduction of natural microflora surface contamination, but 5% acetic acid will not significantly augment this reduction.

  3. Methods of refining and producing isomerized fatty acid esters and fatty acids from natural oil feedstocks

    DOEpatents

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.; Beltran, Leslie V.; Kunz, Linda A.; Pals, Tessa M.; Quinn, Jordan R; Behrends, Jr., Raymond T.; Bernhardt, Randal J.

    2016-07-05

    Methods are provided for refining natural oil feedstocks and producing isomerized esters and acids. The methods comprise providing a C4-C18 unsaturated fatty ester or acid, and isomerizing the fatty acid ester or acid in the presence of heat or an isomerization catalyst to form an isomerized fatty ester or acid. In some embodiments, the methods comprise forming a dibasic ester or dibasic acid prior to the isomerizing step. In certain embodiments, the methods further comprise hydrolyzing the dibasic ester to form a dibasic acid. In certain embodiments, the olefin is formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having unsaturated esters.

  4. Photochemical formation of hydroxyl radical by constituents of natural waters

    SciTech Connect

    Vaughan, P.P.; Blough, N.V.

    1998-10-01

    A new method is employed to determine the rates of photochemical hydroxyl radical (OH) formation in aqueous solutions and in natural waters under both aerobic and anaerobic conditions. Quantum yields for OH formation from the photolysis of nitrate and nitrite obtained by this method are in good agreement with previous measurements. Photolysis of Suwannee River fulvic acid (SRFA) solutions produced the hydroxyl radical under anaerobic conditions in proportion to the SRFA concentration. Under aerobic conditions, the quantum yields for OH formation were slightly higher and exhibited a different wavelength dependence than those obtained under anaerobic conditions. Experiments employing catalase indicate that Fenton chemistry can account for at most 50% of the total signal under aerobic conditions for SRFA irradiated at 310 and 320 nm. These results indicate the presence of a dioxygen-independent pathway of hydroxyl radical production that cannot be assigned to nitrate/nitrite photolysis or to Fenton chemistry. Results from the preliminary application of this method to natural waters are also presented.

  5. Sources and speciation of aluminium and silicon in natural waters.

    PubMed

    Farmer, V C

    1986-01-01

    The aluminosilicate minerals of igneous and metamorphic rocks are mostly unstable in earth-surface weathering conditions. In the tropics and subtropics, they are transformed to stable end-products (crystalline clay minerals, oxides and hydroxides) that largely conserve aluminium and iron. In noncalcareous soils in temperature and boreal climates, aluminium can be markedly mobile, and is precipitated as metastable products that include hydrous aluminosilicates, hydroxyaluminium polymers in or on 2:1 layer silicates, and complexes with soil organic matter. The aluminosilicate precipitates formed at pH less than 5.5 have structures related to imogolite, a unidimensional crystal in the form of a tube of 2.3 nm outer diameter. These metastable precipitates, both organic and inorganic, are readily remobilized on further acidification, and can release aluminium into streams if the solutions are not neutralized in the subsoil. Three classes of soluble aluminium species in natural waters have been distinguished by their rate of reaction with complexing reagents, and their rate of adsorption on cation-exchange columns. These are: (a) unreactive, acid-soluble, Al, (b) labile monomeric Al, and (c) non-liable monomeric Al. Group (b) includes simple inorganic species (e.g. Al3+, AlOH2+, AlF2+), and group (c) is thought to include organic complexes. In contrast, silicon occurs dominantly as Si(OH)4 monomers in natural water. Its metastable precipitates include hydrous aluminosilicates and biogenic opal.

  6. Monitored Natural Attenuation For Radionuclides In Ground Water - Technical Issues

    EPA Science Inventory

    Remediation of ground water contaminated with radionuclides may be achieved using attenuation-based technologies. These technologies may rely on engineered processes (e.g., bioremediation) or natural processes (e.g., monitored natural attentuation) within the subsurface. In gen...

  7. Isolation of nonvolatile, organic solutes from natural waters by zeotrophic distillation of water from N,N-dimethylformamide

    USGS Publications Warehouse

    Leenheer, J.A.; Brown, P.A.; Stiles, E.A.

    1987-01-01

    Nonvolatile, organic solutes that comprise the dissolved organic carbon (DOC) in saline waters were isolated by removal of the water by distillation from a N,N-dimethylformamideformic acid-acetonitrile mixture. Salts isolated with the DOC were removed by crystallization of sodium chloride and sodium sulfate from the solvent mixture, removal of silicic acid by acidification and precipitation, removal of boric acid by methylation and volatilization, and removal of phosphate by zinc acetate precipitation. Chemical alteration of the organic solutes was minimized during evaporative concentration steps by careful control of acid concentrations in the solvent mixture and was minimized during drying by conversion of the samples to pyridinium and sodium salts. Recoveries of various hydrophilic organic standards from aqueous salt solutions and recoveries of natural organic solutes from various water samples varied from 60 to 100%. Losses of organic solutes during the isolation procedure were nonselective and related to the number of salt- and precipitate-washing cycles in the procedure.

  8. TECHNIQUES AND METHODS FOR THE DETERMINATION OF HALOACETIC ACIDS IN POTABLE WATER

    EPA Science Inventory

    Haloethanoic (haloacetic) acids (HAAs) are formed as disinfection byproducts (DBPs) during the chlorination of natural water to make it fit for consumption. Sundry analytical techniques have been applied in order to determine the concentrations of the HAAs in potable water suppli...

  9. Florida Sunshine -- Natural Source for Heating Water

    SciTech Connect

    Not Available

    2002-05-01

    This brochure, part of the State Energy Program (SEP) Stellar Project series, describes a utility solar hot water program in Lakeland, Florida. It is the first such utility-run solar hot water program in the country.

  10. Calcium and bromide contents of natural waters

    USGS Publications Warehouse

    Anderson, R.J.; Graf, D.L.; Jones, B.F.

    1966-01-01

    The linear relation observed in a log Ca++ versus log Br - plot for subsurface Cl- waters is attributed to ultrafiltration by shale of sea water and fresh water that have passed through sedimentary rocks since their formation. Reactions between these solutions and sedimentary minerals, particularly dolomitization, must have contributed additional Ca+ + to solution.

  11. Calcium and bromide contents of natural waters.

    PubMed

    Anderson, R J; Graf, D L; Jones, B F

    1966-09-30

    The linear relation observed in a log Ca++ versus log Brplot for subsurface Cl- waters is attributed to ultrafiltration by shale of sea water and fresh water that have passed through sedimentary rocks since their formation. Reactions between these solutions and sedimentary minerals, particularly dolomitization, must have contributed additional Ca++ to solution.

  12. Influence of natural acidity and fisheries management activities upon the status of Adirondack fish populations

    SciTech Connect

    Retzsch, W.C.; Everett, A.G.

    1981-01-01

    Acidification and the disappearance of fish from some Adirondack waters does not appear to be caused solely by acid rain. Acidification is a natural process under certain conditions and precipitation acidified by industrial emissions appears to be only one of many possible causes of pond, lake and stream acidification. Factors other than acid precipitation can cause acidification or reduce fish stocks. As a result of glaciation, northern New York State has hundreds of glacial ponds and lakes, most of which are dystrophic or oligotrophic. Many such waters are located in the western and central portions of the Adirondacks, an area frequently cited as exhibiting the most pronounced effects of acid rain. It is widely recognized that natural unpolluted bogs and peat deposits result in low pH environments. Seasonal and weather conditions also appear to have a substantial effect upon the acidity of peat-bog outflows. An evaluation of recent survey data on critically acidified Adirondack waters indicates that of 192 waters with values less than pH 5.0, approximately 61 percent appear to be directly influenced by natural bog conditions and an additional 14 percent are probably influenced. A review of historical and recent survey data suggest that significant factors, such as natural causes of acidification, low oxygen concentrations, high CO/sub 2/ and H/sub 2/S concentrations, and extreme temperatures may have been ignored or underestimated in evaluating the cause of acidification and fish disappearances in some Adirondack waters. Another factor responsible for the current status of fish stocks in the Adirondacks involves past and present fishery resource management activities.

  13. Isolation of organic acids from large volumes of water by adsorption chromatography

    USGS Publications Warehouse

    Aiken, George R.

    1984-01-01

    The concentrations of dissolved organic carbon from most natural waters ranges from 1 to 20 milligrams carbon per liter, of which approximately 75 percent are organic acids. These acids can be chromatographically fractionated into hydrophobic organic acids, such as humic substances, and hydrophilic organic acids. To effectively study any of these organic acids, they must be isolated from other organic and inorganic species, and concentrated. Usually, large volumes of water must be processed to obtain sufficient quantities of material, and adsorption chromatography on synthetic, macroporous resins has proven to be a particularly effective method for this purpose. The use of the nonionic Amberlite XAD-8 and Amberlite XAD-4 resins and the anion exchange resin Duolite A-7 for isolating and concentrating organic acids from water is presented.

  14. Total alkalinity versus buffer value (capacity) as a sensitivity indicator for fresh waters receiving acid rain

    SciTech Connect

    Faust, S.D.

    1983-09-01

    The frequently stated idea that total alkalinity is a measure of the buffer capacity of a natural water is refuted. Total alkalinity is a measure of the acid neutralizing capacity, equivalents/liter, of a water. In natural waters, the carbonate system provides most of this neutralizing capacity. In as much as the pH values of natural fresh waters lie below 8.3, the total alkalinity is, for all intents and purposes, the total bicarbonate content. Any contributions of carbonate and hydroxide to total alkalinity are nil. The buffer capacity or buffer value is the relation between the increment of a strong base, or strong acid, that causes a one unit change in the pH value. The values of total alkalinity and pH, considered individually cannot give an accurate assessment of the impact of acid deposition on a natural water. Rather it is necessary to combine the pH and alkalinity values into the beta concept in order to assess accurately and to calculate the capacity of a natural water to resist the impact of acid deposition. An analytical determination of total alkalinity is given with an application of the beta value. 17 references, 2 figures, 4 tables.

  15. Nitrate removal using natural clays modified by acid thermoactivation

    NASA Astrophysics Data System (ADS)

    Mena-Duran, C. J.; Sun Kou, M. R.; Lopez, T.; Azamar-Barrios, J. A.; Aguilar, D. H.; Domínguez, M. I.; Odriozola, J. A.; Quintana, P.

    2007-04-01

    Groundwater pollution by nitrates is a widespread problem in many locations in the world. The underground aquatic mantle of the Peninsula of Yucatan is highly vulnerable due to its karstic nature. Adsorption methods are a good choice for nitrate elimination. In this work, a natural calcium bentonite was modified by acid thermoactivation with HCl and H 2SO 4, and tested as a media for nitrate removal in an aqueous solution. The nitrate concentration in the solution was measured by FT-IR, using the Lambert-Beer law. Clay characterization was carried out by X-ray diffraction and FT-IR spectroscopy; surface area was measured by the BET method.

  16. Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

    PubMed

    Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

    2012-11-01

    To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids. PMID:23050492

  17. Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

    PubMed

    Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

    2012-11-01

    To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids.

  18. Critical loads of acidity for surface waters in China.

    PubMed

    Duan, L; Hao, J; Xie, S; Du, K

    2000-01-31

    For further control of acid rain and sulphur dioxide pollution, the Chinese government has designated the Acid Rain Control Zone and the Sulphur Dioxide Pollution Control Zone for those areas that are, or could become, affected by acid deposition or ambient sulphur dioxide concentrations. One of the most important principles for designating the Acid Rain Control Zone is that the critical load is exceeded by the sulphur deposition. Through the steady-state water chemistry method (SSWC), critical loads of acidity for surface waters were mapped based on available data. Results show that surface waters sensitive to acid deposition, i.e. surface waters with low critical loads, are mainly found in north-east China, on the Tibetan Plateau, and in north-west China. Compared with the critical loads of soils, critical loads of surface waters are usually higher in almost all areas in China. The reason for very low critical loads of surface waters in some regions dominated by soils geologically not sensitive to acid deposition may be attributed to the low temperature, high altitude and low runoff. In contrast, surface waters in south China are not susceptible to acid deposition, and so far acidification of surface water has not been found in spite of the heavy acid rain. As can be seen from the critical load exceedance map, nearly 10% of the surface waters are subject to risk of acidification in 1995.

  19. Relationships of anion-exchange sorption of boron from natural thermal-spring water

    SciTech Connect

    Meichik, N.R.; Leikin, Yu.A.; Antipov, M.A.; Goryacheva, N.V.; Klimenko, I.S.; Medvedev, S.A.; Galitskaya, N.B.

    1988-02-20

    Boric acid is one of the characteristic components of Kamchatka waters. Extraction of boron from thermal waters for production of potable water is closely linked with current problems of multiproduct utilization of resources and protection of the environment. The authors have investigated the possibilities of using ion exchange for extraction of boron from natural waters, and studied the sorption relationships by a dynamic method. They synthesized a macroporous anion-exchanger based on a copolymer of styrene with divinylbenzene, containing N-methylglucamine groups (ANB-11 resin). ANB-11 resin had high sorption capacity for boron anions during sorption from thermal-spring water. The experimental data were described by Elkins equation.

  20. Acidity-Facilitated Mobilization of Surface Clay Colloid from Natural Sand Medium

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Wang, C.; Mohanty, B. P.

    2010-12-01

    Colloid mobilization and migration in a soil system has attracted increasing scrutiny for its role in facilitating colloid-borne transport of contaminants in the environments. In many previous studies, pH was evoked as a major factor in mobilizing surface colloids through inducing favorable surface charge and electrostatic conditions. The possible direct role of acidity with H+ as a chemical agent has remained largely obscured behind the indirect role of pH. In this study, we demonstrated through column flow-through tests that cyclical elution of natural sand media with weak acid and base solutions can greatly facilitate detachment and transport of surface clay colloids. We found that while elevating pH to an alkaline condition helped release the loosely-attached surface clays, a pretreatment with H+ could facilitate the mobilization of chemically-bonded clay colloids through lysing of labile Ca and Mg ions. A quantitative relation was observed that 1 mmol H+ could lyse about 0.5 mmol Ca2+ and Mg2+ and subsequently resulted in a release of about 1,200 mg clay during base elution when repulsive force between particles dominated. Natural organic acids such as citric acid and acetic acid in environment-relevant low concentrations (<1mM and pH>5.0) were as effective as HCl with a stronger acidic condition. The small mass ratio of Ca and Mg over colloid released and the nature of weak acid used suggest that the mobilization was less likely due to dissolution of cement casing than lysing of labile interstitial Ca and Mg by H+, which severed Ca and Mg bridging bonds between particles. Natural acidity is generated in abundance from various bio- and geochemical processes; e.g., many plants produce citric acid through citric acid cycle metabolism; biodegradation of dead organic matter forms humic acids. We postulate that natural proton dynamics in tendon with pH oscillation accompanied with various soil biogeochemical processes could play a major role in subsurface clay

  1. Preparation of PES ultrafiltration membranes with natural amino acids based zwitterionic antifouling surfaces

    NASA Astrophysics Data System (ADS)

    Xu, Chen; Liu, Xiaojiu; Xie, Binbin; Yao, Chen; Hu, Wenhan; Li, Yi; Li, Xinsong

    2016-11-01

    In this report, a simple and facile approach to enhance the antifouling property of poly(ether sulfone) (PES) ultrafiltration membrane was developed by grafting natural amino acids onto surface. First of all, poly(ether sulfone) composite membranes blended with poly(glycidyl methacrylate) were fabricated by phase inversion method followed by grafting of different types of natural amino acids onto the membrane surface through epoxy ring opening reaction. The analysis of attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR) and X-ray photoelectron spectroscopy (XPS) verified the substantial enrichment of amino acids onto the surface of PES membranes. The hydrophilicity of the PES membranes was improved after grafting amino acids. The mechanical property and morphologies of the PES membranes proved that their basic performances were not obviously affected by grafting reaction, and these parameters were all still in the typical range for ultrafiltration membranes. The antifouling property of the grafted PES membranes against bovine serum albumin (BSA) and lysozyme (Lyz) was investigated in detail. It was found that PES membranes incorporated with neutral amino acids exhibited higher fouling resistance to both BSA and Lyz than the parent PES membrane. It can be ascribed to the formation of zwitterionic structure on the surface consisting of protonated secondary amino cations and carboxyl anions. Meanwhile, PES membranes grafted with charged amino acids had better antifouling properties against protein with same electric charges and improved adsorption related to protein with opposite electric charges. Furthermore, the ultrafiltration performance of the zwitterionic PES membranes was evaluated. The results showed that the modified membranes possessed of enhanced pure water flux, relative flux recovery and mildly lower rejection. The Darcy's Law analysis illustrated that the acidic amino acid grafted PES membranes had much lower permeation

  2. Nature: "Water, Water, Everywhere, nor Any Drop to Drink"

    ERIC Educational Resources Information Center

    Heinhorst, Sabine; Cannon, Gordon

    2004-01-01

    The difficulties faced by developing countries in obtaining clean water, and its misuse in advanced countries are reported. The new application of zeolites, or molecular synthesis of aluminosilicates in the desalination or purification of water forecasts a brighter future.

  3. Natural Versus Anthropogenic Remediation of Streams Impacted by Acid Mine Drainage in Southeast Ohio

    NASA Astrophysics Data System (ADS)

    Clinton, T.; Lopez, D. L.

    2004-12-01

    Three streams that have been affected by acid mine drainage in southeast Ohio have been investigated (Sulphur Run in the Federal Creek watershed, Rock Run in the Monday Creek watershed, and Buffer Run in the Raccoon Creek watershed). Sulphur Run neutralizes acidic inputs naturally due to its strong buffering capacity acquired from water-rock interactions with the abundant carbonate lithology surrounding the stream. Rock Run and Buffer Run have been anthropogenically remediated using successive alkalinity producing wetlands, open limestone channels, and alkaline capping of adjacent coal refuse piles. The objective of this study is to compare the water quality evolution of the three streams. For this purpose, water and sediment samples were collected for chemical analysis and in-situ flow rate, alkalinity, acidity, pH, dissolved oxygen, and conductivity were measured. Preliminary results reveal that the pH of Sulphur Run, which never drops below 6.7, increases steadily along the flow path. Downstream of the remediation sites, the pH of Rock Run and Buffer Run is always below 4 and declines along the flow path, possibly due to a combination of additional acidic inputs downstream from the main source and the oxidation of metals, leading to hydrolysis reactions that produce additional hydrogen protons. The net alkalinity of Sulphur Run increases steadily downstream, reflecting the effectiveness of a continuous supply of alkaline material at neutralizing acidic inputs. Both Buffer Run and Rock Run are net acidic, suggesting that armoring of the open limestone channels by metal precipitates is impeding the recovery of water quality. The early results indicate that remediation schemes that do not mimic nature by providing a long term, steady supply of alkaline material appear to be ineffective.

  4. The dissolution of natural and artificial dusts in glutamic acid

    NASA Astrophysics Data System (ADS)

    Ling, Zhang; Faqin, Dong; Xiaochun, He

    2015-06-01

    This article describes the characteristics of natural dusts, industrial dusts, and artificial dusts, such as mineral phases, chemical components, morphological observation and size. Quartz and calcite are the main phases of natural dusts and industrial dusts with high SiO2 and CaO and low K2O and Na2O in the chemical composition. The dissolution and electrochemical action of dusts in glutamic acid liquor at the simulated human body temperature (37 °C) in 32 h was investigated. The potential harm that the dust could lead to in body glutamic acid acidic environment, namely biological activity, is of great importance for revealing the human toxicological mechanism. The changes of pH values and electric conductivity of suspension of those dusts were similar, increased slowly in the first 8 h, and then the pH values increased rapidly. The total amount of dissolved ions of K, Ca, Na, and Mg was 35.4 to 429 mg/kg, particularly Ca was maximal of 20 to 334 mg/kg. The total amount of dissolved ions of Fe, Zn, Mn, Pb, and Ba was 0.18 to 5.59 mg/kg and in Al and Si was 3.0 to 21.7 mg/kg. The relative solubility order of dusts in glutamic acid is wollastonite > serpentine > sepiolite, the cement plant industrial dusts > natural dusts > power plant industrial dusts. The wollastonite and cement plant industrial dusts have the highest solubility, which also have high content of CaO; this shows that there are a poorer corrosion-resisting ability and lower bio-resistibility. Sepiolite and power plant industrial dusts have lowest solubility, which also have high content of SiO2; this shows that there are a higher corrosion-resisting ability and stronger bio-resistibility.

  5. OZONATION BYPRODUCTS: IDENTIFICATION OF BROMOHYDRINS FROM THE OZONATION OF NATURAL WATERS WITH ENHANCED BROMIDE LEVELS

    EPA Science Inventory

    When ozone is used in the treatment of drinking water, it reacts with both inorganic and organic compounds to form byproducts. f bromide is present, it may be oxidized to hydrobromous acid, which may than react with natural organic matter to form brominated organic compounds. he ...

  6. Determination of uranium in natural waters

    USGS Publications Warehouse

    Thatcher, L.L.; Barker, F.B.

    1957-01-01

    The fluorophotometric determination of uranium was studied to develop a procedure applicable to the routine analysis of waters. Three grams of the high carbonate flux are used in a dilution procedure with spiking. Because of the comparatively high reflectivity of this large disk and the low uranium concentration, a correction for nonquenched light is required. A formula is developed to compensate for the effect, an electrical fusion device is described, and the problem of fixing uranium in waters is discussed.

  7. One pot, rapid and efficient synthesis of water dispersible gold nanoparticles using alpha-amino acids.

    PubMed

    Wangoo, Nishima; Kaur, Sarabjit; Bajaj, Manish; Jain, D V S; Sharma, Rohit K

    2014-10-31

    A detailed study on the synthesis of spherical and monodispersed gold nanoparticles (AuNPs) using all of the 20 naturally occurring α-amino acids has been reported. The synthesized nanoparticles have been further characterized using various techniques such as absorbance spectroscopy, transmission electron microscopy, dynamic light scattering and nuclear magnetic resonance. Size control of the nanoparticles has been achieved by varying the ratio of the gold ion to the amino acid. These monodispersed water soluble AuNPs synthesized using non-toxic, naturally occurring α-amino acids as reducing and capping/stabilizing agents serve as a remarkable example of green chemistry.

  8. One pot, rapid and efficient synthesis of water dispersible gold nanoparticles using alpha-amino acids

    NASA Astrophysics Data System (ADS)

    Wangoo, Nishima; Kaur, Sarabjit; Bajaj, Manish; Jain, D. V. S.; Sharma, Rohit K.

    2014-10-01

    A detailed study on the synthesis of spherical and monodispersed gold nanoparticles (AuNPs) using all of the 20 naturally occurring α-amino acids has been reported. The synthesized nanoparticles have been further characterized using various techniques such as absorbance spectroscopy, transmission electron microscopy, dynamic light scattering and nuclear magnetic resonance. Size control of the nanoparticles has been achieved by varying the ratio of the gold ion to the amino acid. These monodispersed water soluble AuNPs synthesized using non-toxic, naturally occurring α-amino acids as reducing and capping/stabilizing agents serve as a remarkable example of green chemistry.

  9. Water ICE: Ion Exclusion Chromatography of Very Weak Acids with a Pure Water Eluent.

    PubMed

    Liao, Hongzhu; Shelor, C Phillip; Dasgupta, Purnendu K

    2016-05-01

    Separation of ions or ionizable compounds with pure water as eluent and detecting them in a simple fashion has been an elusive goal. It has been known for some time that carbonic acid can be separated from strong acids by ion chromatography in the exclusion mode (ICE) using only water as the eluent. The practice of water ICE was shown feasible for very weak acids like silicate and borate with a dedicated element specific detector like an inductively coupled plasma mass spectrometer (ICPMS), but this is rarely practical in most laboratories. Direct conductometric detection is possible for H2CO3 but because of its weak nature, not especially sensitive; complex multistep ion exchange methods do not markedly improve this LOD. It will clearly be impractical in acids that are weaker still. By using a permeative amine introduction device (PAID, Anal. Chem. 2016 , 88 , 2198 - 2204 ) as a conductometric developing agent, we demonstrate that a variety of weak acids (silicate, borate, arsenite, cyanide, carbonate, and sulfide) cannot only be separated on an ion exclusion column, they can be sensitively detected (LODs 0.2-0.4 μM). We observe that the elution order is essentially the same as that on a nonfunctionalized poly(styrene-divinylbenzene) column using 1-10% acetonitrile as eluent and follows the reverse order of the polar surface area (PSA) of the analyte molecules. PSA values have been widely used to predict biological transport of pharmaceuticals across a membrane but never to predict chromatographic behavior. We demonstrate the application of the technique by measuring the silicate and borate depth profiles in the Pacific Ocean; the silicate results show an excellent match with results from a reference laboratory. PMID:27075932

  10. Peracetic acid: A new biocide for industrial water applications

    SciTech Connect

    Kramer, J.F.

    1997-12-01

    Peracetic acid is rapidly cidal at low concentrations against a broad spectrum of microorganisms, including gram-positive and gram-negative bacteria, yeasts, molds, and algae under a wide variety of conditions. It is also effective against anaerobic and spore forming bacteria. Peracetic acid is effective at killing biofilm microorganisms at low concentrations and short contact times. Unlike a number of other biocides, the biocidal activity of peracetic acid is not affected by pH or water hardness and biocidal activity is retained even in the presence of organic matter. For these reasons, peracetic acid is well suited as a biocide in industrial cooling water and papermaking systems. Peracetic acid is compatible with additives commonly used in these systems. Although peracetic acid is a potent biocide, it is unique in that it does not produce toxic byproducts and its decomposition products, acetic acid, water and oxygen, are innocuous and environmentally acceptable.

  11. Acoustic properties of organic acid mixtures in water

    NASA Technical Reports Server (NTRS)

    Macavei, I.; Petrisor, V.; Auslaender, D.

    1974-01-01

    The variation of the rate of propagation of ultrasounds in organic acid mixtures in water points to structural changes caused by interactions that take place under conditions of thermal agitation, at different acid concentrations. At the same time, a difference is found in the changes in velocity as a function of the length of the carbon chain of the acids in the mixture as a result of their effect on the groups of water molecules associated by hydrogen bonds.

  12. General Synthesis of Amino Acid Salts from Amino Alcohols and Basic Water Liberating H2.

    PubMed

    Hu, Peng; Ben-David, Yehoshoa; Milstein, David

    2016-05-18

    An atom-economical and environmentally friendly method to transform amino alcohols to amino acid salts using just basic water, without the need of pre-protection or added oxidant, catalyzed by a ruthenium pincer complex, is developed. Water is the solvent, the source of the oxygen atom of the carboxylic acid group, and the actual oxidant, with liberation of dihydrogen. Many important and useful natural and unnatural amino acid salts can be produced in excellent yields by applying this new method. PMID:27139983

  13. Taurine and ellagic acid: two differently-acting natural antioxidants.

    PubMed

    Cozzi, R; Ricordy, R; Bartolini, F; Ramadori, L; Perticone, P; De Salvia, R

    1995-01-01

    Naturally occurring antimutagenic compounds are extensively analyzed for their capacity to protect cells from induced damage. We selected two agents, taurine and ellagic acid, treated in the literature as antioxidants, but whose activity is insufficiently known. This paper reports on the ability of these agents to act against damage induced by mitomycin-C and hydrogen peroxide in Chinese hamster ovary cells cultivated in vitro. Cytogenetic and cytofluorimetric analyses were performed. Ellagic acid proved to have more than one mechanism of action, probably as a scavenger of oxygen species produced by H2O2 treatment, and as a protector of the DNA double helix from alkylating agent injury. In our experimental conditions, taurine seems able to scavenge oxygen species.

  14. Degradation of benzoic acid and its derivatives in subcritical water.

    PubMed

    Lindquist, Edward; Yang, Yu

    2011-04-15

    In this research, the stability of benzoic acid and three of its derivatives (anthranilic acid, salicylic acid, and syringic acid) under subcritical water conditions was investigated. The stability studies were carried out at temperatures ranging from 50 to 350°C with heating times of 10-630 min. The degradation of the benzoic acid derivatives increased with rising temperature and the acids became less stable with longer heating time. The three benzoic acid derivatives showed very mild degradation at 150°C. Severe degradation of benzoic acid derivatives was observed at 200°C while their complete degradation occurred at 250°C. However, benzoic acid remained stable at temperatures up to 300°C. The degradation products of benzoic acid and the three derivatives were identified and quantified by HPLC and confirmed by GC/MS. Anthranilic acid, salicylic acid, syringic acid, and benzoic acid in high-temperature water underwent decarboxylation to form aniline, phenol, syringol, and benzene, respectively.

  15. Proton-binding study of standard and reference fulvic acids, humic acids, and natural organic matter

    NASA Astrophysics Data System (ADS)

    Ritchie, Jason D.; Perdue, E. Michael

    2003-01-01

    The acid-base properties of 14 standard and reference materials from the International Humic Substances Society (IHSS) were investigated by potentiometric titration. Titrations were conducted in 0.1 M NaCl under a nitrogen atmosphere, averaging 30 min from start to finish. Concentrations of carboxyl groups and phenolic groups were estimated directly from titration curves. Titration data were also fit to a modified Henderson-Hasselbalch model for two classes of proton-binding sites to obtain "best fit" parameters that describe proton-binding curves for the samples. The model was chosen for its simplicity, its ease of implementation in computer spreadsheets, and its excellent ability to describe the shapes of the titration curves. The carboxyl contents of the IHSS samples are in the general order: terrestrial fulvic acids > aquatic fulvic acids > Suwannee River natural organic matter (NOM) > aquatic humic acids > terrestrial humic acids. Overall, fulvic acids and humic acids have similar phenolic contents; however, all of the aquatically derived samples have higher phenolic contents than the terrestrially derived samples. The acid-base properties of reference Suwannee River NOM are surprisingly similar to those of standard Suwannee River humic acid. Results from titrations in this study were compared with other published results from both direct and indirect titrations. Typically, carboxyl contents for the IHSS samples were in agreement with the results from both methods of titration. Phenolic contents for the IHSS samples were comparable to those determined by direct titrations, but were significantly less than estimates of phenolic content that were based on indirect titrations with Ba(OH) 2 and Ca(OAc) 2. The average phenolic-to-carboxylic ratio of the IHSS samples is approximately 1:4. Models that assume a 1:2 ratio of phenolic-to-carboxylic groups may overestimate the relative contribution of phenolic groups to the acid-base chemistry of humic substances.

  16. Library of Antifouling Surfaces Derived From Natural Amino Acids by Click Reaction.

    PubMed

    Xu, Chen; Hu, Xin; Wang, Jie; Zhang, Ye-Min; Liu, Xiao-Jiu; Xie, Bin-Bin; Yao, Chen; Li, Yi; Li, Xin-Song

    2015-08-12

    Biofouling is of great concern in numerous applications ranging from ophthalmological implants to catheters, and from bioseparation to biosensors. In this report, a general and facile strategy to combat surface fouling is developed by grafting of amino acids onto polymer substrates to form zwitterionic structure through amino groups induced epoxy ring opening click reaction. First of all, a library of poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) hydrogels with zwitterionic surfaces were prepared, resulting in the formation of pairs of carboxyl anions and protonated secondary amino cations. The analysis of attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed the successful immobilization of amino acids on the hydrogel surfaces. After that, the contact angle and equilibrium water content of the modified hydrogels showed that the hydrogels exhibited improved hydrophilicity compared with the parent hydrogel. Furthermore, the protein deposition was evaluated by bicinchoninic acid assay using bovine serum albumin (BSA) and lysozyme as models. The results indicated that the performance of the hydrogels was determined by the nature of incorporated amino acid: the hydrogels incorporated with neutral amino acids had nonspecific antiadsorption capability to both BSA and lysozyme; the hydrogels incorporated with charged amino acids showed antiadsorption behaviors against protein with same charge and enhanced adsorption to the protein with opposite charge; the optimal antiadsorption performance was observed on the hydrogels incorporated with polar amino acids with a hydroxyl residual. The improvement of antiprotein fouling of the neutral amino acids grafted hydrogels can be ascribed to the formation of zwitterionic surfaces. Finally, a couple of soft contact lenses grafted with amino acids were fabricated having improved antifouling property and hydrophilicity. The result demonstrated the success of

  17. Water oxidation reaction in natural and artificial photosynthetic systems

    SciTech Connect

    Yano, Junko; Yachandra, Vittal

    2013-12-10

    Understanding the structure and mechanism of water oxidation catalysts is an essential component for developing artificial photosynthetic devices. In the natural water oxidation catalyst, the geometric and electronic structure of its inorganic core, the Mn{sub 4}CaO{sub 5} cluster, has been studied by spectroscopic and diffraction measurements. In inorganic systems, metal oxides seem to be good candidates for water oxidation catalysts. Understanding the reaction mechanism in both natural and oxide-based catalysts will helpin further developing efficient and robust water oxidation catalysts.

  18. Determination of uranium in natural waters

    USGS Publications Warehouse

    Barker, Franklin Butt; Johnson, J.O.; Edwards, K.W.; Robinson, B.P.

    1965-01-01

    A method is described for the determination of very low concentrations of uranium in water. The method is based on the fluorescence of uranium in a pad prepared by fusion of the dried solids from the water sample with a flux of 10 percent NaF 45.5 percent Na2CO3 , and 45.5 percent K2CO3 . This flux permits use of a low fusion temperature and yields pads which are easily removed from the platinum fusion dishes for fluorescence measurements. Uranium concentrations of less than 1 microgram per liter can be determined on a sample of 10 milliliters, or less. The sensitivity and accuracy of the method are dependent primarily on the purity of reagents used, the stability and linearity of the fluorimeter, and the concentration of quenching elements in the water residue. A purification step is recommended when the fluorescence is quenched by more than 30 percent. Equations are given for the calculation of standard deviations of analyses by this method. Graphs of error functions and representative data are also included.

  19. Determination of spectral signatures of substances in natural waters

    NASA Technical Reports Server (NTRS)

    Klemas, V.; Philpot, W. D.; Davis, G.

    1978-01-01

    Optical remote sensing of water pollution offers the possibility of fast, large scale coverage at a relatively low cost. The possibility of using the spectral characteristics of the upwelling light from water for the purpose of ocean water quality monitoring was explained. The work was broken into several broad tasks as follows: (1) definition of a remotely measured spectral signature of water, (2) collection of field data and testing of the signature analysis, and (3) the possibility of using LANDSAT data for the identification of substances in water. An attempt to extract spectral signatures of acid waste and sediment was successful.

  20. Peracetic acid: A new biocide for industrial water applications

    SciTech Connect

    Kramer, J.F.

    1997-08-01

    Peracetic acid is rapidly cidal at low concentrations against a broad spectrum of microorganisms, including gram-positive and gram-negative bacteria, yeasts, molds, and algae under a wide variety of conditions. It is also effective against anaerobic and spore-forming bacteria. Peracetic acid is effective at killing biofilm microorganisms at low concentrations and short contact times. Unlike a number of other biocides, the biocidal activity of peracetic acid is not affected by pH or water hardness and is retained even in the presence of organic matter. For these reasons, peracetic acid is well-suited as a biocide in industrial cooling water and paper-making systems. It is also compatible with additives commonly used in these systems. Although peracetic acid is a potent biocide, it is unique in that it does not produce toxic byproducts and its decomposition products (acetic acid, water, and oxygen) are innocuous and environmentally acceptable.

  1. Silicon Isotope Fractionation During Acid Water-Igneous Rock Interaction

    NASA Astrophysics Data System (ADS)

    van den Boorn, S. H.; van Bergen, M. J.; Vroon, P. Z.

    2007-12-01

    ), the &δ&&30Si value of dissolved silicon in the lake water must be even higher. We infer that progressive cation removal alone is inadequate to describe rock dissolution and silicification by acid fluid. Exchange of silicon between the solution and mineral phases probably accompanied the alteration process. This hypothesis is qualitatively consistent with the idea that elements in solution take part in the formation of altered silica-rich layers at mineral-solution interfaces, as invoked to interpret surface reactions during silicate mineral weathering (e.g., Adriaens et al., 1999; Hellmann et al., 2003). References Adriaens et al., 1999. Surf. Interface Anal., 27: 8-23 Basile-Doelsch et al., 2006. Nature, 433: 399-402. Hellmann et al., 2003. Phys. Chem. Minerals, 30: 192-197.

  2. Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

    NASA Technical Reports Server (NTRS)

    Amashukeli, Xenia; Pelletier, Christine C.; Kirby, James P.; Grunthaner, Frank J.

    2007-01-01

    Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor- phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert ( Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids ( alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1 - 70 parts- per- billion. Subcritical water extraction efficiency was examined over the temperature range of 30 - 325 degrees C, at pressures of 17.2 or 20.0 MPa, and for water- sample contact equilibration times of 0 - 30 min. None of the amino acids were extracted in detectable amounts at 30 degrees C ( at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 degrees C and 250 degrees C ( at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 degrees C ( at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 degrees C, 17.2 MPa, and a water- sample contact equilibration time of 10 min.

  3. Corrosion testing in natural waters: Second volume

    SciTech Connect

    Kain, R.M.; Young, W.T.

    1997-12-31

    This is the second STP of the same title. The first volume, STP 1086, was published in 1990 and contained papers on seawater corrosivity, crevice corrosion resistance of stainless steels, corrosion fatigue testing, and corrosion in potable water. Since then, final results have become available from the worldwide study on corrosion behavior of metals in seawater, and additional studies have been performed that should be brought to the attention of the corrosion engineering community. The second volume contains these studies. Papers have been processed separately for inclusion on the data base.

  4. Mercury Photolytic Transformation Affected by Low-Molecular-Weight Natural Organics in Water

    SciTech Connect

    He, Feng; Zheng, Wang; Gu, Baohua; Liang, Liyuan

    2012-01-01

    Mechanisms by which dissolved organic matter (DOM) mediates the photochemical reduction of Hg(II) in aquatic ecosystems are not fully understood, owing to the heterogeneous nature and complex structural properties of DOM. In this work, naturally occurring aromatic compounds including salicylic, 4-hydrobenzoic, anthranilic, 4-aminobenzoic, and phthalic acid were systematically studied as surrogates for DOM in order to gain an improved mechanistic understanding of these compounds in the photoreduction of Hg(II) in water. We show that the photoreduction rates of Hg(II) are influenced not only by the substituent functional groups such as OH, NH2 and COOH on the benzene ring, but also the positioning of these functional groups on the ring structure. The Hg(II) photoreduction rate decreases in the order anthranilic acid > salicylic acid > phthalic acid according to the presence of the NH2, OH, COOH functional groups on benzoic acid. The substitution position of the functional groups affects reduction rates in the order anthranilic acid > 4-aminobenzoic acid and salicylic acid > 4-hydroxybenzoic acid. Reduction rates correlate strongly with ultraviolet (UV) absorption of these compounds and their concentrations, suggesting that the formation of organic free radicals during photolysis of these compounds is responsible for Hg(II) photoreduction. These results provide insight into the role of low-molecular-weight organic compounds and possibly DOM in Hg photoredox transformation and may thus have important implications for understanding Hg geochemical cycling in the environment.

  5. Biomimetic water-collecting materials inspired by nature.

    PubMed

    Zhu, Hai; Guo, Zhiguang; Liu, Weimin

    2016-03-11

    Nowadays, water shortage is a severe issue all over the world, especially in some arid and undeveloped areas. Interestingly, a variety of natural creatures can collect water from fog, which can provide a source of inspiration to develop novel and functional water-collecting materials. Recently, as an increasingly hot research topic, bioinspired materials with the water collection ability have captured vast scientific attention in both practical applications and fundamental research studies. In this review, we summarize the mechanisms of water collection in various natural creatures and present the fabrications, functions, applications, and new developments of bioinspired materials in recent years. The theoretical basis related to the phenomenon of water collection containing wetting behaviors and water droplet transportations is described in the beginning, i.e., the Young's equation, Wenzel model, Cassie model, surface energy gradient model and Laplace pressure equation. Then, the water collection mechanisms of three typical and widely researched natural animals and plants are discussed and their corresponding bioinspired materials are simultaneously detailed, which are cactus, spider, and desert beetles, respectively. This is followed by introducing another eight animals and plants (butterfly, shore birds, wheat awns, green bristlegrass, the Cotula fallax plant, Namib grass, green tree frogs and Australian desert lizards) that are rarely reported, exhibiting water collection properties or similar water droplet transportation. Finally, conclusions and outlook concerning the future development of bioinspired fog-collecting materials are presented. PMID:26898232

  6. Reduction of turbidity of water using locally available natural coagulants.

    PubMed

    Asrafuzzaman, Md; Fakhruddin, A N M; Hossain, Md Alamgir

    2011-01-01

    Turbidity imparts a great problem in water treatment. Moringa oleifera, Cicer arietinum, and Dolichos lablab were used as locally available natural coagulants in this study to reduce turbidity of synthetic water. The tests were carried out, using artificial turbid water with conventional jar test apparatus. Optimum mixing intensity and duration were determined. After dosing water-soluble extracts of Moringa oleifera, Cicer arietinum, and Dolichos lablab reduced turbidity to 5.9, 3.9, and 11.1 nephelometric turbidity unit (NTU), respectively, from 100 NTU and 5, 3.3, and 9.5, NTU, respectively, after dosing and filtration. Natural coagulants worked better with high, turbid, water compare to medium, or low, turbid, water. Highest turbidity reduction efficiency (95.89%) was found with Cicer arietinum. About 89 to 96% total coliform reduction were also found with natural coagulant treatment of turbid water. Using locally available natural coagulants, suitable, easier, and environment friendly options for water treatment were observed.

  7. Reduction of Turbidity of Water Using Locally Available Natural Coagulants

    PubMed Central

    Asrafuzzaman, Md.; Fakhruddin, A. N. M.; Hossain, Md. Alamgir

    2011-01-01

    Turbidity imparts a great problem in water treatment. Moringa oleifera, Cicer arietinum, and Dolichos lablab were used as locally available natural coagulants in this study to reduce turbidity of synthetic water. The tests were carried out, using artificial turbid water with conventional jar test apparatus. Optimum mixing intensity and duration were determined. After dosing water-soluble extracts of Moringa oleifera, Cicer arietinum, and Dolichos lablab reduced turbidity to 5.9, 3.9, and 11.1 nephelometric turbidity unit (NTU), respectively, from 100 NTU and 5, 3.3, and 9.5, NTU, respectively, after dosing and filtration. Natural coagulants worked better with high, turbid, water compare to medium, or low, turbid, water. Highest turbidity reduction efficiency (95.89%) was found with Cicer arietinum. About 89 to 96% total coliform reduction were also found with natural coagulant treatment of turbid water. Using locally available natural coagulants, suitable, easier, and environment friendly options for water treatment were observed. PMID:23724307

  8. Influence of decenylsuccinic Acid on water permeability of plant cells.

    PubMed

    Lee, O Y; Stadelmann, E J; Weiser, C J

    1972-11-01

    Decenylsuccinic acid altered permeability to water of epidermal cells of bulb scales of Allium cepa and of the leaf midrib of Rhoeo discolor. Water permeability, as determined by deplasmolysis time measurements, was related to the dose of undissociated decenylsuccinic acid (mm undissociated decenylsuccinic acid x minute). No relationship was found between permeability and total dose of decenylsuccinic acid, or dose of dissociated decenylsuccinic acid, suggesting that the undissociated molecule was the active factor in permeability changes and injury.At doses which did not damage cells (0.0008 to 0.6 [mm of the undissociated molecule x minute]) decenylsuccinic acid decreased water permeability. At higher doses (e.g., 4 to 8 [mm x minute]) injury to cells was common and decenylsuccinic acid increased permeability. Doses above the 10 to 20 (mm x minute) range were generally lethal. The plasmolysis form of uninjured cells was altered and protoplasmic swelling occasionally was observed. The dose-dependent reversal of water permeability changes (decreased to increased permeability) may reflect decenylsuccinic acid-induced changes in membrane structure. Reported effects of decenylsuccinic acid on temperature dependence of permeability and frost resistance were not verified. PMID:16658227

  9. Determination of phosphorus in natural waters: A historical review.

    PubMed

    Worsfold, Paul; McKelvie, Ian; Monbet, Phil

    2016-04-28

    The aim of this paper is to introduce a virtual special issue that reviews the development of analytical approaches to the determination of phosphorus species in natural waters. The focus is on sampling and sample treatment, analytical methods and quality assurance of the data. The export of phosphorus from anthropogenic activities (from diffuse and point sources) can result in increased primary production and eutrophication, and potentially the seasonal development of toxic algal blooms, which can significantly impact on water quality. Therefore the quantification of phosphorus species in natural waters provides important baseline data for studying aquatic phosphorus biogeochemistry, assessing ecosystem health and monitoring compliance with legislation. PMID:27046205

  10. A comparison of neutralization efficiency of chemicals with respect to acidic Kopili River water

    NASA Astrophysics Data System (ADS)

    Kapil, Nibedita; Bhattacharyya, Krishna G.

    2016-02-01

    Among all the renewable sources of energy, hydropower is the most potential source which is economical, non-polluting and eco-friendly. The efficiency of hydropower plant in the long run depends on many factors like water and sediment quality. Erosive and corrosive wear of machine parts like turbine is a complex phenomenon. The problem becomes more acute if the hydroenvironment is acidic in nature. The wear and tear due to corrosion/erosion caused by acid mine drainage (AMD) from coal mines reduces the efficiency and the life of the equipments. In this work, neutralization of the acidic water of the Kopili River, Assam, India was investigated using a number of basic chemicals and quantitatively estimating their effectiveness and actual requirement. The acidic water of the river, used as the cooling water, has been found responsible for damaging the equipments of the Kopili Hydro Electric Power Project (KHEP), Assam/Meghalaya, India by reducing the life of all metallic parts through corrosion. In this work, use is made of a number of basic materials like calcium carbonate, calcium hydroxide, calcium oxide, sodium carbonate, sodium hydroxide, and ammonia to examine their neutralization efficiency with respect to the acidic water and it was found that quick lime or raw lime (CaO) has the highest neutralization capacity. Suggestions have been made for meeting the problem of acidity of the river water.

  11. Benzoic Acid and Chlorobenzoic Acids: Thermodynamic Study of the Pure Compounds and Binary Mixtures With Water.

    PubMed

    Reschke, Thomas; Zherikova, Kseniya V; Verevkin, Sergey P; Held, Christoph

    2016-03-01

    Benzoic acid is a model compound for drug substances in pharmaceutical research. Process design requires information about thermodynamic phase behavior of benzoic acid and its mixtures with water and organic solvents. This work addresses phase equilibria that determine stability and solubility. In this work, Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was used to model the phase behavior of aqueous and organic solutions containing benzoic acid and chlorobenzoic acids. Absolute vapor pressures of benzoic acid and 2-, 3-, and 4-chlorobenzoic acid from literature and from our own measurements were used to determine pure-component PC-SAFT parameters. Two binary interaction parameters between water and/or benzoic acid were used to model vapor-liquid and liquid-liquid equilibria of water and/or benzoic acid between 280 and 413 K. The PC-SAFT parameters and 1 binary interaction parameter were used to model aqueous solubility of the chlorobenzoic acids. Additionally, solubility of benzoic acid in organic solvents was predicted without using binary parameters. All results showed that pure-component parameters for benzoic acid and for the chlorobenzoic acids allowed for satisfying modeling phase equilibria. The modeling approach established in this work is a further step to screen solubility and to predict the whole phase region of mixtures containing pharmaceuticals. PMID:26886302

  12. Natural and pyrogenic humic acids at goethite and natural oxide surfaces interacting with phosphate.

    PubMed

    Hiemstra, Tjisse; Mia, Shamim; Duhaut, Pierre-Benoît; Molleman, Bastiaan

    2013-08-20

    Fulvic and humic acids have a large variability in binding to metal (hydr) oxide surfaces and interact differently with oxyanions, as examined here experimentally. Pyrogenic humic acid has been included in our study since it will be released to the environment in the case of large-scale application of biochar, potentially creating Darks Earths or Terra Preta soils. A surface complexation approach has been developed that aims to describe the competitive behavior of natural organic matter (NOM) in soil as well as model systems. Modeling points unexpectedly to a strong change of the molecular conformation of humic acid (HA) with a predominant adsorption in the Stern layer domain at low NOM loading. In soil, mineral oxide surfaces remain efficiently loaded by mineral-protected organic carbon (OC), equivalent with a layer thickness of ≥ ~0.5 nm that represents at least 0.1-1.0% OC, while surface-associated OC may be even three times higher. In natural systems, surface complexation modeling should account for this pervasive NOM coverage. With our charge distribution model for NOM (NOM-CD), the pH-dependent oxyanion competition of the organo-mineral oxide fraction can be described. For pyrogenic HA, a more than 10-fold increase in dissolved phosphate is predicted at long-term applications of biochar or black carbon. PMID:23875678

  13. Maleic acid solvation in mixed water-ethanol solvents

    NASA Astrophysics Data System (ADS)

    Usacheva, T. R.; Kuz'mina, I. A.; Sharnin, V. A.; Tukumova, I. R.

    2012-04-01

    Heat effects of maleic acid dissolution in mixed water-ethanol solvents at 298.15 K are determined by means of calorimetry. A rise in exothermicity of maleic acid solvation is observed upon changes in the solvent copmosition in the direction of H2O → EtOH, the minimum being at ˜0.2 mol fraction of EtOH.

  14. Photolytic dehalogenation of disinfection byproducts in water by natural sunlight irradiation.

    PubMed

    Abusallout, Ibrahim; Hua, Guanghui

    2016-09-01

    The aqueous photolysis of halogenated disinfection byproducts (DBPs) by natural sunlight irradiation was studied to determine their photolytic dehalogenation kinetics. Total organic halogen analysis was used to quantify the dehalogenation extents of DBPs during outdoor photolysis experiments. Dichloroacetamide, chloral hydrate, chloroform, dichloroacetonitrile, monochloro-, monobromo-, dichloro-, dibromo-, and trichloroacetic acids were generally resistant to photolytic dehalogenation and showed less than 10% reduction after 6 h sunlight irradiation. Monoiodoacetic acid, tribromoacetic acid, bromoform, dibromoacetonitrile, and trichloronitromethane showed moderate to high dehalogenation degrees with half-lives of 4.0-19.3 h. Diiodoacetic acid, triiodoacetic acid, and iodoform degraded rapidly under the sunlight irradiation and exhibited half-lives of 5.3-10.2 min. In general, the photosensitive cleavage of carbon-halogen bonds of DBPs increased with increasing number of halogens (tri- > di- > mono-halogenated) and size of the substituted halogens (I > Br > Cl). Nitrate, nitrite, and pH had little impact on the photodehalogenation of DBPs under typical levels in surface waters. The presence of natural organic matter (NOM) inhibited the photodehalogenation of DBPs by light screening. The NOM inhibiting effects were more pronounced for the fast degrading iodinated DBPs. The results of this study improve our understanding about the photolytic dehalogenation of wastewater-derived DBPs in surface waters during water reuse. PMID:27289205

  15. TAILORING ACTIVATED CARBONS FOR ENHANCED REMOVAL OF NATURAL ORGANIC MATTER FROM NATURAL WATERS. (R828157)

    EPA Science Inventory

    Several pathways have been employed to systematically modify two granular activated carbons (GACs), F400 (coal-based) and Macro (wood-based), for examining adsorption of dissolved natural organic matter (DOM) from natural waters. A total of 24 activated carbons with different ...

  16. Pectin functionalized with natural fatty acids as antimicrobial agent.

    PubMed

    Calce, Enrica; Mignogna, Eleonora; Bugatti, Valeria; Galdiero, Massimiliano; Vittoria, Vittoria; De Luca, Stefania

    2014-07-01

    Several pectin derivatives were prepared by chemical modifications of the polysaccharide with natural fatty acids. The obtained biodegradable pectin-based materials, pectin-linoleate, pectin-oleate and pectin-palmitate, were investigated for their antimicrobial activity against several bacterial strains, Staphylococcus aureus and Escherichia coli. Good results were obtained for pectin-oleate and pectin-linoleate, which inhibit the growth of the selected microorganisms by 50-70%. They exert the better antimicrobial activity against S. aureus. Subsequently, the pectin-oleate and the pectin-linoleate samples were coated on polyethylene films and were assessed for their capacity to capture the oxygen molecules, reducing its penetration into the polymeric support. These results confirmed a possible application of the new materials in the field of active food packaging.

  17. Effects of slightly acidic electrolysed drinking water on mice.

    PubMed

    Inagaki, Hideaki; Shibata, Yoshiko; Obata, Takahiro; Kawagoe, Masami; Ikeda, Katsuhisa; Sato, Masayoshi; Toida, Kazumi; Kushima, Hidemi; Matsuda, Yukihisa

    2011-10-01

    Slightly acidic electrolysed (SAE) water is a sanitizer with strong bactericidal activity due to hypochlorous acid. We assessed the safety of SAE water as drinking water for mice at a 5 ppm total residual chlorine (TRC) concentration to examine the possibility of SAE water as a labour- and energy-saving alternative to sterile water. We provided SAE water or sterile water to mice for 12 weeks, during which time we recorded changes in body weight and weekly water and food intakes. At the end of the experiment, all of the subject animals were sacrificed to assess serum aspartate aminotransferase, alanine aminotransferase and creatinine levels and to examine the main organs histopathologically under a light microscope. In addition, we investigated the bacteria levels of both types of water. We found no difference in functional and morphological health condition indices between the groups. Compared with sterile water, SAE water had a relatively higher ability to suppress bacterial growth. We suggest that SAE water at 5 ppm TRC is a safe and useful alternative to sterile water for use as drinking water in laboratory animal facilities.

  18. Pasteurization of naturally contaminated water with solar energy.

    PubMed Central

    Ciochetti, D A; Metcalf, R H

    1984-01-01

    A solar box cooker (SBC) was constructed with a cooking area deep enough to hold several 3.7-liter jugs of water, and this was used to investigate the potential of using solar energy to pasteurize naturally contaminated water. When river water was heated either in the SBC or on a hot plate, coliform bacteria were inactivated at temperatures of 60 degrees C or greater. Heating water in an SBC to at least 65 degrees C ensures that the water will be above the milk pasteurization temperature of 62.8 degrees C for at least an hour, which appears sufficient to pasteurize contaminated water. On clear or partly cloudy days, with the SBC facing magnetic south in Sacramento, bottom water temperatures of at least 65 degrees C could be obtained in 11.1 liters of water during the 6 weeks on either side of the summer solstice, in 7.4 liters of water from mid-March through mid-September, and in 3.7 liters of water an additional 2 to 3 weeks at the beginning and end of the solar season. Periodic repositioning of the SBC towards the sun, adjusting the back reflective lid, and preheating water in a simple reflective device increased final water temperatures. Simultaneous cooking and heating water to pasteurizing temperatures was possible. Additional uses of the SBC to pasteurize soil and to decontaminate hospital materials before disposal in remote areas are suggested. PMID:6712206

  19. Pasteurization of naturally contaminated water with solar energy

    SciTech Connect

    Ciochetti, D.A.; Metcalf, R.H.

    1984-02-01

    A solar box cooker (SBC) was constructed with a cooking area deep enough to hold several 3.7-liter jugs of water, and this was used to investigate the potential of using solar energy to pasteurize naturally contaminated water. When river water was heated either in the SBC or on a hot plate, coliform bacteria were inactivated at temperatures of 60/sup 0/C or greater. Heating water in an SBC to at least 65/sup 0/C ensures that the water will be above the milk pasteurization temperature of 62.8/sup 0/C for at least an hour, which appears sufficient to pasteurize contaminated water. On clear or partly cloudy days, with the SBC facing magnetic south in Sacramento, bottom water temperatures of at least 65/sup 0/C could be obtained in 11.1 liters of water during the 6 weeks on either side of the summer solstice, in 7.4 liters of water from mid-March through mid-September, and in 3.7 liters of water an additional 2 to 3 weeks at the beginning and end of the solar season. Periodic repositioning of the SBC towards the sun, adjusting the back reflective lid, and preheating water in a simple reflective device increased final water temperatures. Simultaneous cooking and heating water to pasteurizing temperatures was possible. Additional uses of the SBC to pasteurize soil and to decontaminate hospital materials before disposal in remote areas are suggested. 14 references.

  20. Oleic Acid: Natural variation and potential enhancement in oilseed crops.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oleic acid is a monounsaturated omega 9 fatty acid (MUFA, C18:1) which can be found in various plant lipids and animal fats. Unlike omega 3 (a-linolenic acid, C18:3) and omega 6 (linoleic acid, C18:2) fatty acids which are essential because they cannot be synthesized by humans and must be obtained f...

  1. A Prebiotic Chemistry Experiment on the Adsorption of Nucleic Acids Bases onto a Natural Zeolite

    NASA Astrophysics Data System (ADS)

    Anizelli, Pedro R.; Baú, João Paulo T.; Gomes, Frederico P.; da Costa, Antonio Carlos S.; Carneiro, Cristine E. A.; Zaia, Cássia Thaïs B. V.; Zaia, Dimas A. M.

    2015-09-01

    There are currently few mechanisms that can explain how nucleic acid bases were synthesized, concentrated from dilute solutions, and/or protected against degradation by UV radiation or hydrolysis on the prebiotic Earth. A natural zeolite exhibited the potential to adsorb adenine, cytosine, thymine, and uracil over a range of pH, with greater adsorption of adenine and cytosine at acidic pH. Adsorption of all nucleic acid bases was decreased in artificial seawater compared to water, likely due to cation complexation. Furthermore, adsorption of adenine appeared to protect natural zeolite from thermal degradation. The C=O groups from thymine, cytosine and uracil appeared to assist the dissolution of the mineral while the NH2 group from adenine had no effect. As shown by FT-IR spectroscopy, adenine interacted with a natural zeolite through the NH2 group, and cytosine through the C=O group. A pseudo-second-order model best described the kinetics of adenine adsorption, which occurred faster in artificial seawaters.

  2. A Prebiotic Chemistry Experiment on the Adsorption of Nucleic Acids Bases onto a Natural Zeolite.

    PubMed

    Anizelli, Pedro R; Baú, João Paulo T; Gomes, Frederico P; da Costa, Antonio Carlos S; Carneiro, Cristine E A; Zaia, Cássia Thaïs B V; Zaia, Dimas A M

    2015-09-01

    There are currently few mechanisms that can explain how nucleic acid bases were synthesized, concentrated from dilute solutions, and/or protected against degradation by UV radiation or hydrolysis on the prebiotic Earth. A natural zeolite exhibited the potential to adsorb adenine, cytosine, thymine, and uracil over a range of pH, with greater adsorption of adenine and cytosine at acidic pH. Adsorption of all nucleic acid bases was decreased in artificial seawater compared to water, likely due to cation complexation. Furthermore, adsorption of adenine appeared to protect natural zeolite from thermal degradation. The C=O groups from thymine, cytosine and uracil appeared to assist the dissolution of the mineral while the NH2 group from adenine had no effect. As shown by FT-IR spectroscopy, adenine interacted with a natural zeolite through the NH2 group, and cytosine through the C=O group. A pseudo-second-order model best described the kinetics of adenine adsorption, which occurred faster in artificial seawaters. PMID:25754589

  3. A Prebiotic Chemistry Experiment on the Adsorption of Nucleic Acids Bases onto a Natural Zeolite.

    PubMed

    Anizelli, Pedro R; Baú, João Paulo T; Gomes, Frederico P; da Costa, Antonio Carlos S; Carneiro, Cristine E A; Zaia, Cássia Thaïs B V; Zaia, Dimas A M

    2015-09-01

    There are currently few mechanisms that can explain how nucleic acid bases were synthesized, concentrated from dilute solutions, and/or protected against degradation by UV radiation or hydrolysis on the prebiotic Earth. A natural zeolite exhibited the potential to adsorb adenine, cytosine, thymine, and uracil over a range of pH, with greater adsorption of adenine and cytosine at acidic pH. Adsorption of all nucleic acid bases was decreased in artificial seawater compared to water, likely due to cation complexation. Furthermore, adsorption of adenine appeared to protect natural zeolite from thermal degradation. The C=O groups from thymine, cytosine and uracil appeared to assist the dissolution of the mineral while the NH2 group from adenine had no effect. As shown by FT-IR spectroscopy, adenine interacted with a natural zeolite through the NH2 group, and cytosine through the C=O group. A pseudo-second-order model best described the kinetics of adenine adsorption, which occurred faster in artificial seawaters.

  4. Comparative genotoxicity of halogenated acetic acids found in drinking water.

    PubMed

    Giller, S; Le Curieux, F; Erb, F; Marzin, D

    1997-09-01

    Three short-term assays (SOS chromotest, Ames fluctuation test and newt micronucleus test) were performed to detect the genotoxic activity of organohalides, compounds likely to be found in chlorinated and/or ozonated drinking water: monochloro-, dichloro- and trichloroacetic acids and monobromo-, dibromo- and tribromoacetic acids. With the SOS chromotest, only three of the chemicals studied (dichloroacetic acid, dibromo- and tribromoacetic acids) were found to induce primary DNA damage in Escherichia coli PQ 37. In the Ames fluctuation test, all the compounds except monochloroacetic acid showed mutagenic activity in Salmonella typhimurium strain TA100. In these two in vitro tests, a good correlation between increasing number of substituents and decreasing mutagenicity was observed. Namely, the toxicity of brominated and chlorinated acetic acids decreased when the number of substituents increased. The newt micronucleus test detected a weak clastogenic effect on the peripheral blood erythrocytes of Pleurodeles waltl larvae for trichloroacetic acid only.

  5. A theoretical study on ascorbic acid dissociation in water clusters.

    PubMed

    Demianenko, Eugeniy; Ilchenko, Mykola; Grebenyuk, Anatoliy; Lobanov, Victor; Tsendra, Oksana

    2014-03-01

    Dissociation of ascorbic acid in water has been studied by using a cluster model. It was examined by density functional theory (DFT) with the В3LYP, M06, and wB97XD functionals and a 6-311++G(d,p) basis set. The thermodynamic and kinetic characteristics of proton transfer from ascorbic acid molecule to water clusters were calculated as well as the equilibrium constants (pK a ) for the related processes. The used functionals in the DFT method together with continuum solvent models provided results close to the experimental data for the dissociation constant of ascorbic acid in aqueous solution.

  6. NEUROXOTOXICITY PRODUCED BY DIBROMOACETIC ACID IN DRINKING WATER OF RATS.

    EPA Science Inventory

    The Safe Drinking Water Act requires that EPA consider noncancer endpoints for the assessment of adverse human health effects of disinfection byproducts (DBPs). Dibromoacetic acid (DBA) is one of many DBPs produced by the chlorination of drinking water. Its chlorinated analog, ...

  7. Occurrence of perfluoroalkyl acids in environmental waters in Vietnam.

    PubMed

    Duong, Hanh Thi; Kadokami, Kiwao; Shirasaka, Hanako; Hidaka, Rento; Chau, Hong Thi Cam; Kong, Lingxiao; Nguyen, Trung Quang; Nguyen, Thao Thanh

    2015-03-01

    This is the first nationwide study of perfluoroalkyl acids (PFAAs) in environmental waters in Vietnam. Twenty-eight river water and 22 groundwater samples collected in four major cities and 14 river water samples from the Red River were screened to investigate the occurrence and sources of 16 PFAAs. Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were the most prevalent of 11 detected PFAAs with maximum concentrations in urban river water of 5.3, 18 and 0.93ngL(-1), respectively, and in groundwater of 8.2, 4.5 and 0.45ngL(-1), respectively. PFAAs in the Red River water were detected at low levels. PFAA concentrations in river water were higher in the rainy season than in the dry season, possibly due to storm water runoff, a common phenomenon in Southeast Asian countries. The highest concentrations of PFAAs in river water were observed in samples from highly populated and industrialized areas, perhaps sourced from sewage. The PFAA concentrations observed were similar to those in other Southeast Asian countries, but lower than in developed nations. From the composition profiles of PFAAs, industrial products containing PFAAs imported from China and Japan might be one of the major sources of PFAAs in the Vietnamese aquatic environment. According to the health-based values and advisory issued by the United States Environmental Protection Agency (USEPA), the concentrations of detected PFAAs in this study do not pose an immediate health risk to humans and aquatic organisms.

  8. Acid Base Equilibrium in a Lipid/Water Gel

    NASA Astrophysics Data System (ADS)

    Streb, Kristina K.; Ilich, Predrag-Peter

    2003-12-01

    A new and original experiment in which partition of bromophenol blue dye between water and lipid/water gel causes a shift in the acid base equilibrium of the dye is described. The dye-absorbing material is a monoglyceride food additive of plant origin that mixes freely with water to form a stable cubic phase gel; the nascent gel absorbs the dye from aqueous solution and converts it to the acidic form. There are three concurrent processes taking place in the experiment: (a) formation of the lipid/water gel, (b) absorption of the dye by the gel, and (c) protonation of the dye in the lipid/water gel environment. As the aqueous solution of the dye is a deep purple-blue color at neutral pH and yellow at acidic pH the result of these processes is visually striking: the strongly green-yellow particles of lipid/water gel are suspended in purple-blue aqueous solution. The local acidity of the lipid/water gel is estimated by UV vis spectrophotometry. This experiment is an example of host-guest (lipid/water gel dye) interaction and is suitable for project-type biophysics, physical chemistry, or biochemistry labs. The experiment requires three, 3-hour lab sessions, two of which must not be separated by more than two days.

  9. Return of naturally sourced Pb to Atlantic surface waters

    PubMed Central

    Bridgestock, Luke; van de Flierdt, Tina; Rehkämper, Mark; Paul, Maxence; Middag, Rob; Milne, Angela; Lohan, Maeve C.; Baker, Alex R.; Chance, Rosie; Khondoker, Roulin; Strekopytov, Stanislav; Humphreys-Williams, Emma; Achterberg, Eric P.; Rijkenberg, Micha J. A.; Gerringa, Loes J. A.; de Baar, Hein J. W.

    2016-01-01

    Anthropogenic emissions completely overwhelmed natural marine lead (Pb) sources during the past century, predominantly due to leaded petrol usage. Here, based on Pb isotope measurements, we reassess the importance of natural and anthropogenic Pb sources to the tropical North Atlantic following the nearly complete global cessation of leaded petrol use. Significant proportions of up to 30–50% of natural Pb, derived from mineral dust, are observed in Atlantic surface waters, reflecting the success of the global effort to reduce anthropogenic Pb emissions. The observation of mineral dust derived Pb in surface waters is governed by the elevated atmospheric mineral dust concentration of the North African dust plume and the dominance of dry deposition for the atmospheric aerosol flux to surface waters. Given these specific regional conditions, emissions from anthropogenic activities will remain the dominant global marine Pb source, even in the absence of leaded petrol combustion. PMID:27678297

  10. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    PubMed

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters. PMID:26841230

  11. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    PubMed

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters.

  12. Evaluation of natural tracers in an acidic and metal-rich stream

    SciTech Connect

    Bencala, K.E.; McKnight, D.M.; Zellweger, G.W.

    1987-05-01

    In natural waters, a variety of solutes would be appropriate for use as tracers in different situations. Comparisons were made of natural tracers at the confluence of an acidic stream (Snake River) with a pristine stream (Deer Creek) near Montezuma, Colorado. Three comparisons were made during late summer at low-flow conditions to identify the naturally occurring conservative solutes in the stream system: (1) a steady injection of chloride and sodium was used as an artificial, conservative baseline tracer to compare the behavior of silica, sulfate, and fluoride, (2) within the mixing zone of the confluence, comparisons were made of the lateral concentration gradients of sodium, calcium, magnesium, silica, sulfate, and fluoride, and (3) the conservative behavior of naturally occurring calcium, magnesium, silica, sulfate, fluoride, and manganese was evaluated from stream samples collected on four different days. On the basis of the results of these comparisons, manganese and sulfate were used as conservative solutes to demonstrate computation of: (1) the reactive losses of other solutes within the confluence and (2) the ratio of chemical inflows from Deer Creek and the Snake River. The approach used in this evaluation can be applied in the study of chemically similar acidic systems.

  13. Evaluation of Natural Tracers in an Acidic and Metal-Rich Stream

    NASA Astrophysics Data System (ADS)

    Bencala, Kenneth E.; McKnight, Diane M.; Zellweger, Gary W.

    1987-05-01

    In natural waters, a variety of solutes would be appropriate for use as tracers in different situations. Comparisons were made of natural tracers at the confluence of an acidic stream (Snake River) with a pristine stream (Deer Creek) near Montezuma, Colorado. Three comparisons were made during late summer at low-flow conditions to identify the naturally occurring conservative solutes in the stream system: (1) a steady injection of chloride and sodium was used as an artificial, conservative baseline tracer to compare the behavior of silica, sulfate, and fluoride, (2) within the mixing zone of the confluence, comparisons were made of the lateral concentration gradients of sodium, calcium, magnesium, silica, sulfate, and fluoride, and (3) the conservative behavior of naturally occurring calcium, magnesium, silica, sulfate, fluoride, and manganese was evaluated from stream samples collected on four different days. On the basis of the results of these comparisons, manganese and sulfate were used as conservative solutes to demonstrate computation of: (1) the reactive losses of other solutes within the confluence and (2) the ratio of chemical inflows from Deer Creek and the Snake River. The approach used in this evaluation can be applied in the study of chemically similar acidic systems.

  14. Silica gel as a support for inorganic ion- exchangers for the determination of caesium-137 in natural waters.

    PubMed

    Terada, K; Hayakawa, H; Sawada, K; Kiba, T

    1970-10-01

    The preparation and characteristics of ammonium molybdophosphate and potassium or ammonium hexacyanocobalt ferrate supported in silica gel, and their application to the determination of (137)Cs in natural waters are described. Use of columns of these materials gives better recovery of (137)Cs from natural waters (in comparison with co-precipitation with ammonium molybdophosphate), requires less exchanger, so raising the gamma-counting efficiency of (137)Cs, and permits elimination of other radionuclides by washing with hydrofluoric acid.

  15. (The fate of nuclides in natural water systems)

    SciTech Connect

    Turekian, K.K. . Dept. of Geology and Geophysics)

    1989-01-01

    Our research at Yale on the fate of nuclides in natural water systems has three components to it: the study of the atmospheric precipitation of radionuclides and other chemical species; the study of the behavior of natural radionuclides in groundwater and hydrothermal systems; and understanding the controls on the distribution of radionuclides and stable nuclides in the marine realm. In this section a review of our progress in each of these areas is presented.

  16. Is There a Maximum Size of Water Drops in Nature?

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2013-01-01

    In nature, water drops can have a large variety of sizes and shapes. Small droplets with diameters of the order of 5 to 10 µm are present in fog and clouds. This is not sufficiently large for gravity to dominate their behavior. In contrast, raindrops typically have sizes of the order of 1 mm, with observed maximum sizes in nature of around 5 mm in…

  17. [The use of the natural mineral saponite for water decontamination].

    PubMed

    Hyrin, V M; Boĭko, I I; Rudychenko, V F

    1999-01-01

    Sorption properties were studied of natural and activated specimens of saponite with respect to poliomyelitis virus, Coxsackie B 1 and B 6 viruses as well as to Enterobacteriaceae group bacteria. With the purpose of comparing the processes of sorption of microorganisms, other minerals were also used, such as bentonite, alunite, glauconite, ceolite. The natural saponite adsorptive properties were found out to undergo changes during the process of thermoactivation. Mechanisms are discussed of a decontaminating effect of thermoactivated saponite in water.

  18. Thermal decarboxylation of acetic acid: Implications for origin of natural gas

    USGS Publications Warehouse

    Kharaka, Y.K.; Carothers, W.W.; Rosenbauer, R.J.

    1983-01-01

    Laboratory experiments on the thermal decarboxylation of solutions of acetic acid at 200??C and 300??C were carried out in hydrothermal equipment allowing for on-line sampling of both the gas and liquid phases for chemical and stable-carbon-isotope analyses. The solutions had ambient pH values between 2.5 and 7.1; pH values and the concentrations of the various acetate species at the conditions of the experiments were computed using a chemical model. Results show that the concentrations of acetic acid, and not total acetate in solution, control the reaction rates which follow a first order equation based on decreasing concentrations of acetic acid with time. The decarboxylation rates at 200??C (1.81 ?? 10-8 per second) and 300??C (8.17 ?? 10-8 per second) and the extrapolated rates at lower temperatures are relatively high. The activation energy of decarboxylation is only 8.1 kcal/mole. These high decarboxylation rates, together with the distribution of short-chained aliphatic acid anions in formation waters, support the hypothesis that acid anions are precursors for an important portion of natural gas. Results of the ??13C values of CO2, CH4, and total acetate show a reasonably constant fractionation factor of about 20 permil between CO2 and CH4 at 300??C. The ??13C values of CO2 and CH4 are initially low and become higher as decarboxylation increases. ?? 1983.

  19. Home water treatment by direct filtration with natural coagulant.

    PubMed

    Babu, Raveendra; Chaudhuri, Malay

    2005-03-01

    Seeds of the plant species Strychnos potatorum and Moringa oleifera contain natural polyelectrolytes which can be used as coagulants to clarify turbid waters. In laboratory tests, direct filtration of a turbid surface water (turbidity 15-25 NTU, heterotrophic bacteria 280-500 cfu ml(-1), and fecal coliforms 280-500 MPN 100 ml(-1)), with seeds of S. potatorum or M. oleifera as coagulant, produced a substantial improvement in its aesthetic and microbiological quality (turbidity 0.3-1.5 NTU, heterotrophic bacteria 5-20 cfu ml(-1) and fecal coliforms 5-10 MPN 100 ml(-1)). The method appears suitable for home water treatment in rural areas of developing countries. These natural coagulants produce a 'low risk' water; however, additional disinfection or boiling should be practised during localised outbreaks/epidemics of enteric infections.

  20. Density calculation and concentration scale conversions for natural waters

    NASA Astrophysics Data System (ADS)

    Monnin, Christophe

    1994-12-01

    A program is presented that calculates the density of a natural water from its composition. It is based on the recent modeling of the volumetric properties of natural waters at 25°C and 1 bar to high concentrations using Pitzer's equations. The required input is the concentrations of the major solutes of natural waters, that is Na, K, Ca, Mg, Cl, SO 4, HCO 3, and CO 3, expressed in any of the most widely used scales: molinity (grams or moles per kg of solution), molality (moles per kg of water), or molarity (moles or grams per liter). The output consists of the density of the solution, the partial molal volumes of the solutes, and a table in which the input concentrations are converted into all the scales as cited plus the solute mole fractions. The error in t he calculated seawater density is 0.00002 g/cm 3, but it increases to about 0.0004 g/cm 3 for dense brines. The program then is used to calculate the consequences of the approximation that natural waters behave as pure sodium chloride solutions, both for the computed density and for the concentration conversions.

  1. Adsorption of oleic acid at sillimanite/water interface.

    PubMed

    Kumar, T V Vijaya; Prabhakar, S; Raju, G Bhaskar

    2002-03-15

    The interaction of oleic acid at sillimanite-water interface was studied by adsorption, FT-IR, and zeta potential measurements. The isoelectric point (IEP) of sillimanite obtained at pH 8.0 was found to shift in the presence of oleic acid. This shift in IEP was attributed to chemisorption of oleic acid on sillimanite. Adsorption experiments were conducted at pH 8.0, where the sillimanite surface is neutral. The adsorption isotherm exhibited a plateau around 5 micromol/m2 that correspond to a monolayer formation. Adsorption of oleic acid on sillimanite, alumina, and aluminum hydroxide was studied by FT-IR. Chemisorption of oleic acid on the above substrates was confirmed by FT-IR studies. Hydroxylation of mineral surface was found to be essential for the adsorption of oleic acid molecules. These surface hydroxyl sites were observed to facilitate deprotonation of oleic acid and its subsequent adsorption. Thus protons from oleic acid react with surface hydroxyl groups and form water molecules. Based on the experimental results, the mechanism of oleic acid adsorption on mineral substrate was proposed. Free energy of adsorption was estimated using the Stern-Graham equation for a sillimanite-oleate system. PMID:16290466

  2. Theoretical study of water cluster catalyzed decomposition of formic acid.

    PubMed

    Inaba, Satoshi

    2014-04-24

    We have performed a number of quantum chemical simulations to examine water cluster catalyzed decomposition of formic acid. The decomposition of formic acid consists of two competing pathways, dehydration, and decarboxylation. We use the Gaussian 4 method of the Gaussian09 software to locate and optimize a transition state of the decomposition reaction and obtain the activation energy. The decomposition starts by transferring a proton of a formic acid to a water molecule. The de Broglie wavelength of a proton is similar to the width of the potential barrier of the decomposition reaction at low temperature. The tunneling, in which a proton penetrates the potential barrier, enhances the decomposition rate. Water molecules serve as the catalyst in the decomposition and reduce the activation energy. The relay of a proton from a water molecule to a neighboring water molecule is accomplished with little change of the geometry of a molecule, resulting in the reduction of the activation energy. Two water molecules are actively involved in the decomposition reaction to reduce the activation energy. We have also examined the effect of water clusters with three, four, and five water molecules on the decomposition reaction. The noncovalent distance between a hydrogen atom of a water molecule and an oxygen atom of a neighboring water molecule decreases in a water cluster due to the cooperative many-body interactions. A water molecule in a water cluster becomes a better proton donor as well as a better proton acceptor. The activation energy of the decomposition is further decreased by the catalytic effect of a water cluster. We calculate the reaction rate using the transition state theory corrected by the tunneling effect of a proton. The calculated reaction rate of the decarboxylation is smaller than that of the dehydration when less than three water molecules are included in the simulation. However, the major product of the decomposition of a formic acid becomes carbon dioxide

  3. Ozonation of oil sands process water removes naphthenic acids and toxicity.

    PubMed

    Scott, Angela C; Zubot, Warren; MacKinnon, Michael D; Smith, Daniel W; Fedorak, Phillip M

    2008-03-01

    Naphthenic acids are naturally-occurring, aliphatic or alicyclic carboxylic acids found in petroleum. Water used to extract bitumen from the Athabasca oil sands becomes toxic to various organisms due to the presence of naphthenic acids released from the bitumen. Natural biodegradation was expected to be the most cost-effective method for reducing the toxicity of the oil sands process water (OSPW). However, naphthenic acids are poorly biodegraded in the holding ponds located on properties leased by the oil sands companies. In the present study, chemical oxidation using ozone was investigated as an option for mitigation of this toxicity. Ozonation of sediment-free OSPW was conducted using proprietary technology manufactured by Seair Diffusion Systems Inc. Ozonation for 50min generated a non-toxic effluent (based on the Microtox bioassay) and decreased the naphthenic acids concentration by approximately 70%. After 130min of ozonation, the residual naphthenic acids concentration was 2mgl(-1): <5% of the initial concentration in the filtered OSPW. Total organic carbon did not change with 130min of ozonation, whereas chemical oxygen demand decreased by approximately 50% and 5-d biochemical oxygen demand increased from an initial value of 2mgl(-1) to a final value of 15mgl(-1). GC-MS analysis showed that ozonation resulted in an overall decrease in the proportion of high molecular weight naphthenic acids (n> or = 22).

  4. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    PubMed Central

    Fujioka, Kouki; Futamura, Yasuhiro; Shiohara, Tomoo; Hoshino, Akiyoshi; Kanaya, Fumihide; Manome, Yoshinobu; Yamamoto, Kenji

    2009-01-01

    Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin. PMID:19582225

  5. Acidic deposition: State of science and technology. Report 15. Liming acidic surface waters. Final report

    SciTech Connect

    Olem, H.; Thornelof, E.; Sandoy, S.; Schreiber, R.K.

    1990-09-01

    The document describes the science and technology of aquatic liming--a method for improving the water quality of acidic surface waters to restore or enhance fisheries. The report is a comprehensive compilation of years of research in North America and Europe by dozens of scientists. Several mitigation technologies--including those that have only been proposed--are critically evaluated along with the effects of liming on water chemistry and aquatic biota. Through these evaluations, the state of the science and technology of aquatic liming is identified for the reader. Whole-lake liming is now recognized as a valuable management tool for acidic surface waters and their fisheries. However, some liming technologies are considered experimental and will need further evaluation. Distinctions between technologies are included--as is the distinction between liming acidic surface waters and reducing acidifying emissions.

  6. The corrosive nature of manganese in drinking water.

    PubMed

    Alvarez-Bastida, C; Martínez-Miranda, V; Vázquez-Mejía, G; Solache-Ríos, M; Fonseca-Montes de Oca, G; Trujillo-Flores, E

    2013-03-01

    Corrosion problems having to do with drinking water distribution systems are related to many processes and factors and two of them are ionic acidity and carbon dioxide, which were considered in this work. The corrosion character of water is determined by the corrosion indexes of Langelier, Ryznar, Larson, and Mojmir. The results show that pipes made of different materials, such as plastics or metals, are affected by corrosion, causing manganese to be deposited on materials and dissolved in water. The deterioration of the materials, the degree of corrosion, and the deposited corrosion products were determined by X-ray diffraction and Scanning Electron Microscopy. High levels of manganese and nitrate ions in water may cause serious damage to the health of consumers of water. Three wells were examined, one of them presented a high content of manganese; the others had high levels of nitrate ions, which increased the acidity of the water and, therefore, the amount of corrosion of the materials in the distribution systems.

  7. The corrosive nature of manganese in drinking water.

    PubMed

    Alvarez-Bastida, C; Martínez-Miranda, V; Vázquez-Mejía, G; Solache-Ríos, M; Fonseca-Montes de Oca, G; Trujillo-Flores, E

    2013-03-01

    Corrosion problems having to do with drinking water distribution systems are related to many processes and factors and two of them are ionic acidity and carbon dioxide, which were considered in this work. The corrosion character of water is determined by the corrosion indexes of Langelier, Ryznar, Larson, and Mojmir. The results show that pipes made of different materials, such as plastics or metals, are affected by corrosion, causing manganese to be deposited on materials and dissolved in water. The deterioration of the materials, the degree of corrosion, and the deposited corrosion products were determined by X-ray diffraction and Scanning Electron Microscopy. High levels of manganese and nitrate ions in water may cause serious damage to the health of consumers of water. Three wells were examined, one of them presented a high content of manganese; the others had high levels of nitrate ions, which increased the acidity of the water and, therefore, the amount of corrosion of the materials in the distribution systems. PMID:23376288

  8. Aluminum in acidic surface waters: chemistry, transport, and effects.

    PubMed Central

    Driscoll, C T

    1985-01-01

    Ecologically significant concentrations of Al have been reported in surface waters draining "acid-sensitive" watersheds that are receiving elevated inputs of acidic deposition. It has been hypothesized that mineral acids from atmospheric deposition have remobilized Al previously precipitated within the soil during soil development. This Al is then thought to be transported to adjacent surface waters. Dissolved mononuclear Al occurs as aquo Al, as well as OH-, F-, SO4(2-), and organic complexes. Although past investigations have often ignored non-hydroxide complexes of Al, it appears that organic and F complexes are the predominant forms of Al in dilute (low ionic strength) acidic surface waters. The concentration of inorganic forms of Al increases exponentially with decreases in solution pH. This response is similar to the theoretical pH dependent solubility of Al mineral phases. The concentration of organic forms of Al, however, is strongly correlated with variations in organic carbon concentration of surface waters rather than pH. Elevated concentrations of Al in dilute acidic waters are of interest because: Al is an important pH buffer; Al may influence the cycling of important elements like P, organic carbon, and trace metals; and Al is potentially toxic to aquatic organisms. An understanding of the aqueous speciation of Al is essential for an evaluation of these processes. PMID:3935428

  9. Aluminum in acidic surface waters: chemistry, transport, and effects.

    PubMed

    Driscoll, C T

    1985-11-01

    Ecologically significant concentrations of Al have been reported in surface waters draining "acid-sensitive" watersheds that are receiving elevated inputs of acidic deposition. It has been hypothesized that mineral acids from atmospheric deposition have remobilized Al previously precipitated within the soil during soil development. This Al is then thought to be transported to adjacent surface waters. Dissolved mononuclear Al occurs as aquo Al, as well as OH-, F-, SO4(2-), and organic complexes. Although past investigations have often ignored non-hydroxide complexes of Al, it appears that organic and F complexes are the predominant forms of Al in dilute (low ionic strength) acidic surface waters. The concentration of inorganic forms of Al increases exponentially with decreases in solution pH. This response is similar to the theoretical pH dependent solubility of Al mineral phases. The concentration of organic forms of Al, however, is strongly correlated with variations in organic carbon concentration of surface waters rather than pH. Elevated concentrations of Al in dilute acidic waters are of interest because: Al is an important pH buffer; Al may influence the cycling of important elements like P, organic carbon, and trace metals; and Al is potentially toxic to aquatic organisms. An understanding of the aqueous speciation of Al is essential for an evaluation of these processes.

  10. The Determination of Anionic Surfactants in Natural and Waste Waters.

    ERIC Educational Resources Information Center

    Crisp, P. T.; And Others

    1983-01-01

    Background information, procedures, and results of an experiment suitable for measuring subpart per million concentrations of anionic surfactants in natural waters and waste effluents are provided. The experiment required only a spectrophotometer or filter photometer and has been successfully performed by students in an undergraduate environmental…

  11. Protecting Consumers from Contaminated Drinking Water during Natural Disasters

    EPA Science Inventory

    Natural disasters can cause damage and destruction to local water supplies affecting millions of people. Communities should plan for and designate an authorized team to manage and prioritize emergency response in devastated areas. Sections 2.0 and 3.0 describe the Environmental...

  12. Impacts of water quality on chlorine and chlorine dioxide efficacy in natural waters.

    PubMed

    Barbeau, Benoit; Desjardins, Raymond; Mysore, Chandra; Prévost, Michele

    2005-05-01

    The impact of disinfection efficacy in natural waters was evaluated by performing disinfection assays using four untreated surface waters of various qualities and ultra-pure buffered waters as a baseline condition for comparison. Bacillus subtilis spores were spiked in these waters and disinfection assays were conducted at 22 degrees C using either free chlorine or chlorine dioxide. Assays using indigenous aerobic spores were also completed. The inactivation kinetics in natural and ultra-pure buffered waters were not statistically different (at p = 0.05) while using free chlorine, as long as disinfectant decay was taken into account. Filtering natural waters through a 0.45 microm did not improve the sporicidal efficacy of chlorine. For three out of the four waters tested, the efficacy of chlorine dioxide was greater in natural waters compared to that observed in ultra-pure buffered waters. Such results are consistent with previous observations using ultra-pure waters supplemented with NOM-extract from the Suwannee River. Similar to free chlorine results, the impact of filtration (0.45 microm) on the efficacy of chlorine dioxide was not statistically significant.

  13. An empirical NaKCa geothermometer for natural waters

    USGS Publications Warehouse

    Fournier, R.O.; Truesdell, A.H.

    1973-01-01

    An empirical method of estimating the last temperature of water-rock interaction has been devised. It is based upon molar Na, K and Ca concentrations in natural waters from temperature environments ranging from 4 to 340??C. The data for most geothermal waters cluster near a straight line when plotted as the function log ( Na K) + ?? log [ ??? (Ca) Na] vs reciprocal of absolute temperature, where ?? is either 1 3 or 4 3 depending upon whether the water equilibrated above or below 100??C. For most waters tested, the method gives better results than the Na K methods suggested by other workers. The ratio Na K should not be used to estimate temperature if ??? ( MCa) MNa is greater than 1. The Na K values of such waters generally yield calculated temperatures much higher than the actual temperature at which water interacted with the rock. A comparison of the composition of boiling hot-spring water with that obtained from a nearby well (170??C) in Yellowstone Park shows that continued water-rock reactions may occur during ascent of water even though that ascent is so rapid that little or no heat is lost to the country rock, i.e. the water cools adiabatically. As a result of such continued reaction, waters which dissolve additional Ca as they ascend from the aquifer to the surface will yield estimated aquifer temperatures that are too low. On the other hand, waters initially having enough Ca to deposit calcium carbonate during ascent may yield estimated aquifer temperatures that are too high if aqueous Na and K are prevented from further reaction with country rock owing to armoring by calcite or silica minerals. The Na-K-Ca geothermometer is of particular interest to those prospecting for geothermal energy. The method also may be of use in interpreting compositions of fluid inclusions. ?? 1973.

  14. Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

    PubMed

    Beddow, H; Black, S; Read, D

    2006-01-01

    In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution.

  15. Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

    PubMed

    Beddow, H; Black, S; Read, D

    2006-01-01

    In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution. PMID:16303218

  16. Effects of humic and fulvic acids on poliovirus concentration from water by microporous filtration.

    PubMed Central

    Sobsey, M D; Hickey, A R

    1985-01-01

    Because naturally occurring organic matter is thought to interfere with virus adsorption to microporous filters, humic and fulvic acids isolated from a highly colored, soft surface water were used as model organics in studies on poliovirus adsorption to and recovery from electropositive Virosorb 1MDS and electronegative Filterite filters. Solutions of activated carbon-treated tap water containing 3, 10, and 30-mg/liter concentrations of humic or fulvic acid were seeded with known amounts of poliovirus and processed with Virosorb 1MDS filters at pH 7.5 or Filterite filters at pH 3.5 (with and without 5 mM MgCl2). Organic acids caused appreciable reductions in virus adsorption and recovery efficiencies with both types of filter. Fulvic acid caused greater reductions in poliovirus recovery with Virosorb 1MDS filters than with Filterite filters. Fulvic acid interference with poliovirus recovery by Filterite filters was overcome by the presence of 5 mM MgCl2. Although humic acid reduced poliovirus recoveries by both types of filter, its greatest effect was on virus elution and recovery from Filterite filters. Single-particle analyses demonstrated MgCl2 enhancement of poliovirus association with both organic acids at pH 3.5. The mechanisms by which each organic acid reduced virus adsorption and recovery appeared to be different for each type of filter. PMID:2984989

  17. [Composition of fat acids in three Mexican populations of Artemia franciscana from epicontinental waters].

    PubMed

    Malpica Sánchez, Aída; Castro Barrera, Thalía; Sandoval Trujillo, Horacio; Castro Mejía, Jorge; De Lara Andrade, Ramón; Castro Mejía, Germán

    2004-03-01

    In this paper is presented the percentage of fatty acids composition of three Artemia franciscana Mexican populations of epicontinentals waters; two are from natural environments (Coahuila and San Luis Potosf) and one (Texcoco) is a culture fed with Spirulina. Determination of fatty acids composition in each population, was performed by extraction of total lipid by the soxhlet method and the fatty acids methyl esters were determined by gas chromatography. The results show that Artemia of Texcoco contains the six fatty acids recommended for the culture of fish and crustaceans (16:0; 16:1; 18:1; 18:2w6; 18:3w3 and 20:5w3); Artemia from San Luis Potosi showed the poorest content in these acids and Artemia from Coahuila, although it showed a wide profile, it lacks the linolenic acid. When comparing results among the three populations with ecological data that have been published, it can be pointed out that the environment is decisive for this crustacean; Artemia from Texcoco fed with Spirulina showed the largest variety of fatty acids; the other two populations are wild, and lives in different habitats, Artemia of Coahuila is found in waters that are rich in sulfates and Artemia of San Luis Potosf lives in evaporation saltern ponds, built with stone blocks and therefore with scarce phytoplankton growth. Both Artemia populations showed deficiencies in essential fatty acids, mainly the last one.

  18. Improving saline-sodic coalbed natural gas water quality using natural zeolites.

    PubMed

    Ganjegunte, Girisha K; Vance, George F; Gregory, Robert W; Urynowicz, Michael A; Surdam, Ronald C

    2011-01-01

    Management of saline-sodic water from the coalbed natural gas (CBNG) industry in the Powder River Basin (PRB) of Wyoming and Montana is a major environmental challenge. Clinoptilolie zeolites mined in Nevada, California, and New Mexico were evaluated for their potential to remove sodium (Na+) from CBNG waters. Based on the exchangeable cation composition, naturally occurring calcium (Ca2+)-rich zeolites from New Mexico were selected for further evaluation. Batch adsorption experiments were conducted to evaluate the potential of the Ca(2+)-rich natural clinoptilolites to remove Na+ from saline-sodic CBNG waters. Batch adsorption experiments indicated that Na+ adsorption capacity ofclinoptilolite ranged from 4.3 (4 x 6 mesh) to 7.98 g kg(-1) (14 x 40 mesh). Among the different adsorption isotherms investigated, the Freundlich Model fitted the data best for smaller-sized (6 x 8, 6 x 14, and 14 x 40 mesh) zeolites. Passing the CBNG water through Ca(2+)-rich zeolite columns reduced the salt content (electrical conductivity [EC]) by 72% with a concurrent reduction in sodium adsorption 10 mmol 1/2 L(-1/2). Zeolite technology appears to be an effective water treatment alternative to industrial membrane treatment for removing Na+ from poor-quality CBNG waters.

  19. Improving saline-sodic coalbed natural gas water quality using natural zeolites.

    PubMed

    Ganjegunte, Girisha K; Vance, George F; Gregory, Robert W; Urynowicz, Michael A; Surdam, Ronald C

    2011-01-01

    Management of saline-sodic water from the coalbed natural gas (CBNG) industry in the Powder River Basin (PRB) of Wyoming and Montana is a major environmental challenge. Clinoptilolie zeolites mined in Nevada, California, and New Mexico were evaluated for their potential to remove sodium (Na+) from CBNG waters. Based on the exchangeable cation composition, naturally occurring calcium (Ca2+)-rich zeolites from New Mexico were selected for further evaluation. Batch adsorption experiments were conducted to evaluate the potential of the Ca(2+)-rich natural clinoptilolites to remove Na+ from saline-sodic CBNG waters. Batch adsorption experiments indicated that Na+ adsorption capacity ofclinoptilolite ranged from 4.3 (4 x 6 mesh) to 7.98 g kg(-1) (14 x 40 mesh). Among the different adsorption isotherms investigated, the Freundlich Model fitted the data best for smaller-sized (6 x 8, 6 x 14, and 14 x 40 mesh) zeolites. Passing the CBNG water through Ca(2+)-rich zeolite columns reduced the salt content (electrical conductivity [EC]) by 72% with a concurrent reduction in sodium adsorption 10 mmol 1/2 L(-1/2). Zeolite technology appears to be an effective water treatment alternative to industrial membrane treatment for removing Na+ from poor-quality CBNG waters. PMID:21488493

  20. Copper complexation and toxicity to Daphnia in natural waters

    SciTech Connect

    Borgmann, U.; Charlton, C.C.

    1984-01-01

    Toxicity of copper to Daphnia magna in artificial medium, artificial medium plus algae, and natural water from Hamilton Harbour and Lake Ontario was determined, with and without added Tris, in order to test the assumption that free cupric ion concentrations are the same in equivalently toxic media even when total copper concentrations vary. Free cupric ion concentrations were calculated from the increase in the total copper concentration tolerated after Tris addition and from cupric ion electrode measurements. Copper toxicity was greatest in inorganic medium, lowest in inorganic medium plus algae and in Hamilton Harbour water, and intermediate in lake water. However, after Tris addition, toxicity was greatest in lake water and lowest in inorganic medium and inorganic medium plus algae. Both the bioassay and electrode data indicate that free cupric ion concentrations differ in different test waters when toxicity is the same. Free metal concentrations do not, therefore, provide a good measure of copper toxicity for Daphnia in natural waters. 12 references, 1 figure, 1 table.

  1. Progesterone, administered prior to kainic acid, reduces decrements in cognitive performance in the Morris Water Maze

    PubMed Central

    Frye, Cheryl A.; Walf, Alicia

    2013-01-01

    The nature of progesterone (P4)’s neuroprotective effects is of interest. We investigated effects of P4 when administered prior to, or following, kainic acid, which produces ictal activity and damage to the hippocampus, to mediate effects on spatial performance. The hypothesis was that P4, compared to vehicle, would reduce decrements in Morris Water Maze performance induced by kainic acid. Experiment 1: We examined the effects of kainic acid on plasma stress hormone, corticosterone, and progestogen (P4 and its metabolites) levels in plasma and the hippocampus following subcutaneous (s.c.) P4 administration to ovariectomized rats. Rats administered kainic acid had the highest corticosterone levels immediately following injection. P4 is 5α-reduced to dihydroprogesterone (DHP) and subsequently metabolized to 5α-pregnan-3α-ol-20-one (3α,5α-THP) by 3α-hydroxysteroid dehydrogenase. The regimen of P4 utilized produced circulating and hippocampal levels of P4, DHP, and 3α,5α-THP within a physiological range, which decline at 14 hours post-injection, and were not altered by kainic acid. Experiment 2: The physiological P4 regimen was administered to rats before, or following, kainic acid-induced seizures, and later effects on water maze performance were compared to that of rats administered vehicle. Rats administered kainic acid had significantly poorer performance in the water maze (i.e. increased latencies and distances to the hidden platform) than did rats administered vehicle. Administration of P4 before, but not after, kainic acid prevented these performance deficits. Thus, these data suggest that a physiological regimen of P4 can prevent some of the deficits in water maze performance produced by kainic acid. PMID:20715152

  2. Monitoring of trifluoroacetic acid concentration in environmental waters in China.

    PubMed

    Zhang, Jianbo; Zhang, Ying; Li, Jinlong; Hu, Jianxin; Ye, Peng; Zeng, Zheng

    2005-04-01

    It is critically important and extremely meaningful to determine the concentration of TFA in the environmental water in China. This will create background reference for the effects of analyzing the extensive employment of the substitutes to CFCs in China. In this paper a set of analytical methods was described for use in monitoring of trifluoroacetic acid (TFA) concentration of environmental waters including collecting, pre-treatment measures, preserving, concentrating and derivatization of samples from different kinds of environmental waters. The GC with electrical capture detector (ECD) and headspace auto sampler were used in the analysis. The lowest detection limit of the instrument is 0.0004 ng methyl trifluoroacetic acid (MTFA), and the lowest detected concentration with the method is 3.0 ng/ml TFA. TFA collected in various environmental water samples (including rainfall, inland surface water, ground water, and waste water) from nine provinces and autonomous regions in China have been determined by applying the analytical methods created and defined in this work. The results indicate that the concentrations of TFA in nine rainfalls and three snowfalls through the period from 2000 to 2001 ranged from 25 to 220 ng/l, the TFA concentration in the inland surface water samples ranged from 4.7 to 221 ng/l, the concentration of TFA in groundwater samples collected in Beijing was 10 ng/l, and the TFA concentration in coastal water samples ranged from 4.2 to 190.1 ng/l.

  3. Diaromatic sulphur-containing 'naphthenic' acids in process waters.

    PubMed

    West, Charles E; Scarlett, Alan G; Tonkin, Andrew; O'Carroll-Fitzpatrick, Devon; Pureveen, Jos; Tegelaar, Erik; Gieleciak, Rafal; Hager, Darcy; Petersen, Karina; Tollefsen, Knut-Erik; Rowland, Steven J

    2014-03-15

    Polar organic compounds found in industrial process waters, particularly those originating from biodegraded petroleum residues, include 'naphthenic acids' (NA). Some NA have been shown to have acute toxicity to fish and also to produce sub-lethal effects. Whilst some of these toxic effects are produced by identifiable carboxylic acids, acids such as sulphur-containing acids, which have been detected, but not yet identified, may produce others. Therefore, in the present study, the sulphur-containing acids in oil sands process water were studied. A fraction (ca 12% by weight of the total NA containing ca 1.5% weight sulphur) was obtained by elution of methylated NA through an argentation solid phase extraction column with diethyl ether. This was examined by multidimensional comprehensive gas chromatography-mass spectrometry (GCxGC-MS) in both nominal and high resolution mass accuracy modes and by GCxGC-sulphur chemiluminescence detection (GCxGC-SCD). Interpretation of the mass spectra and retention behaviour of methyl esters of several synthesised sulphur acids and the unknowns allowed delimitation of the structures, but not complete identification. Diaromatic sulphur-containing alkanoic acids were suggested. Computer modelling of the toxicities of some of the possible acids suggested they would have similar toxicities to one another and to dehydroabietic acid. However, the sulphur-rich fraction was not toxic or estrogenic to trout hepatocytes, suggesting the concentrations of sulphur acids in this sample were too low to produce any such effects in vitro. Further samples should probably be examined for these compounds. PMID:24252453

  4. NEUTRALIZATION OF ACIDIC GROUND WATER NEAR GLOBE, ARIZONA.

    USGS Publications Warehouse

    Eychaner, James H.; Stollenwerk, Kenneth G.; ,

    1985-01-01

    Highly acidic contaminated water is moving through a shallow aquifer and interacting with streams near Globe, Arizona. Dissolved concentrations reach 3,000 mg/L iron, 150 mg/L copper, and 16,400 mg/L total dissloved solids; pH is as low as 3. 6. Samples from 16 PVC-cased observation wells include uncontaminated, contaminated, transition, and neutralized waters. Chemical reaction with sediments and mixing with uncontaminated water neutralizes the acidic water. The reactions form a transition zone where gypsum replaces calcite and most metals precipitate. Ferric hydroxide also precipitates if sufficient oxygen is available. Abundant gypsum crystals and ferric hydroxide coatings have been recovered from well cuttings. Large sulfate concentrations produce sulfate complexes with many metals that inhibit removal of metals from solution.

  5. Water and acid soluble trace metals in atmospheric particles

    NASA Technical Reports Server (NTRS)

    Lindberg, S. E.; Harriss, R. C.

    1983-01-01

    Continental aerosols are collected above a deciduous forest in eastern Tennessee and subjected to selective extractions to determine the water-soluble and acid-leachable concentrations of Cd, Mn, Pb, and Zn. The combined contributions of these metals to the total aerosol mass is 0.5 percent, with approximately 70 percent of this attributable to Pb alone. A substantial fraction (approximately 50 percent or more) of the acid-leachable metals is soluble in distilled water. In general, this water-soluble fraction increases with decreasing particle size and with increasing frequency of atmospheric water vapor saturation during the sampling period. The pattern of relative solubilities (Zn being greater than Mn, which is approximately equal to Cd, which is greater than Pb) is found to be similar to the general order of the thermodynamic solubilities of the most probable salts of these elements in continental aerosols with mixed fossil fuel and soil sources.

  6. Role of Organic Solutes in the Chemistry Of Acid-Impacted Bog Waters of the Western Czech Republic

    NASA Astrophysics Data System (ADS)

    HrušKa, Jakub; Johnson, Chris E.; KráM, Pavel

    1996-04-01

    In many regions, naturally occurring organic acid anions can effectively buffer mineral acid inputs from atmospheric deposition, moderating their effect on surface water pH. We studied the effect of chronically high inputs of acid rain on the chemistry of three brown-water streams in the western Czech Republic. The dissolved organic acids in the streams were similar in character to those of other systems in Europe and North America. The site densities (the carboxyl group content per mass of C) were similar to values reported from Fenno-Scandia, and the relationship between the apparent pKa and pH conformed to those from two North American studies. Sulfate and organic acid anions (OA-) were the dominant anions in all three streams, yet despite high dissolved organic carbon and total organic acid concentrations, OA - comprised only 21-32% of total anion charge. This pattern was due to very high sulfate concentrations and, in two of the streams, a low degree of dissociation of the organic acids, probably the results of high long-term inputs of strong acids. Stream water pH was highly correlated to sulfate concentration, but uncorrelated with OA-, suggesting that free acidity is controlled by strong mineral acids rather than organic acids. Thus future reductions in strong acid inputs should result in increased pH and a return to organic control over acid-base chemistry.

  7. Chemical modifications of natural triterpenes - glycyrrhetinic and boswellic acids: evaluation of their biological activity

    PubMed Central

    Subba Rao, G. S. R.; Kondaiah, Paturu; Singh, Sanjay K.; Ravanan, Palaniyandi; Sporn, Michael B.

    2008-01-01

    Synthetic analogues of naturally occurring triterpenoids; glycyrrhetinic acid, arjunolic acid and boswellic acids, by modification of A-ring with a cyano- and enone- functionalities, have been reported. A novel method of synthesis of α-cyanoenones from isoxazoles is reported. Bio-assays using primary mouse macrophages and tumor cell lines indicate potent anti-inflammatory and cytotoxic activities associated with cyanoenones of boswellic acid and glycyrrhetinic acid. PMID:20622928

  8. Sublimation of natural amino acids and induction of asymmetry by meteoritic amino acids

    NASA Astrophysics Data System (ADS)

    Tarasevych, Arkadii V.; Guillemin, Jean-Claude

    It is believed that the homochirality of building blocks of life like amino acids (AAs) and sugars is a prerequisite requirement for the origin and evolution of life. Among different mechanisms that might have triggered the initial disparity in the enantiomeric ratio on the primitive Earth, the key roles were assigned to: (i) local chiral symmetry breaking and (ii) the inflow of extraterrestrial matter (eg the carbonaceous meteorites containing non-racemic AAs). Recently it has been revealed that sublimation, a subject almost completely neglected for a long time, gives a pathway to enantioenrichment of natural AAs (1,2 and references herein). Sublimation is however one of the key physical processes that occur on comets. Starting from a mixture with a low content of an enantiopure AA, a partial sublimation gives an important enrichment of the sublimate (1,2). The resulted disparity in the ratio between enantiomers of a partial sublimate is determined by the crystalline nature of the starting mixture: we observed a drastic difference in the behavior of (i) mixtures based on true racemic compounds and (ii) mechanical mixtures of two enantiopure solid phases. On the other hand, combination of crystallization and sublimation can lead to segregation of enantioenriched fractions starting from racemic composition of sublimable aliphatic AAs (Ala, Leu, Pro, Val) in mixtures with non-volatile enantiopure ones (Asn, Asp, Glu, Ser, Thr) (3). The resulted sense of chirality correlates with the handedness of the non-volatile AAs: the observed changes in enantiomeric ratios clearly demonstrate the preferential homochiral interactions and a tendency of natural amino acids to homochiral self-organization. It is noteworthy that just these 5 (Asn, Asp, Glu, Ser, Thr) out of 22 proteinogenic amino acids are able to local symmetry breaking. On the other hand, recent data on the enantiomeric composition of the Tagish Lake, a C2-type carbonaceous meteorite, revealed a large L

  9. Occurrence of perfluoroalkyl acids in environmental waters in Vietnam.

    PubMed

    Duong, Hanh Thi; Kadokami, Kiwao; Shirasaka, Hanako; Hidaka, Rento; Chau, Hong Thi Cam; Kong, Lingxiao; Nguyen, Trung Quang; Nguyen, Thao Thanh

    2015-03-01

    This is the first nationwide study of perfluoroalkyl acids (PFAAs) in environmental waters in Vietnam. Twenty-eight river water and 22 groundwater samples collected in four major cities and 14 river water samples from the Red River were screened to investigate the occurrence and sources of 16 PFAAs. Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were the most prevalent of 11 detected PFAAs with maximum concentrations in urban river water of 5.3, 18 and 0.93ngL(-1), respectively, and in groundwater of 8.2, 4.5 and 0.45ngL(-1), respectively. PFAAs in the Red River water were detected at low levels. PFAA concentrations in river water were higher in the rainy season than in the dry season, possibly due to storm water runoff, a common phenomenon in Southeast Asian countries. The highest concentrations of PFAAs in river water were observed in samples from highly populated and industrialized areas, perhaps sourced from sewage. The PFAA concentrations observed were similar to those in other Southeast Asian countries, but lower than in developed nations. From the composition profiles of PFAAs, industrial products containing PFAAs imported from China and Japan might be one of the major sources of PFAAs in the Vietnamese aquatic environment. According to the health-based values and advisory issued by the United States Environmental Protection Agency (USEPA), the concentrations of detected PFAAs in this study do not pose an immediate health risk to humans and aquatic organisms. PMID:25496738

  10. The effects of acid precipitation runoff on source water quality

    SciTech Connect

    Leibfried, R.T.; DeWalle, D.R.; Sharpe, W.A.

    1984-03-01

    The quality of water in two small streams that provide supplies to the water systems of Jennerstown and Boalsburg, Pa., was monitored during episodes of acid runoff in February 1981 (Card Machine Run) and March 1983 (Galbraith Gap Run): Changes in pH, in the concentration of aluminum, and in the Ryznar Stability Index were determined. The magnitude and potential importance of these changes are discussed.

  11. Effects of acid precipitation runoff on source water quality

    SciTech Connect

    Leibfried, R.T.; Sharpe, W.E.; DeWalle, D.R.

    1984-03-01

    The quality of water in two small streams that provide supplies to the water systems of Jennerstown and Boalsburg, Pa., was monitored during episodes of acid runoff in February 1981 (Card Machine Run) and March 1983 (Galbraith Gap Run). Changes in pH, in the concentration of aluminum, and in the Ryznar Stability Index were determined. The magnitude and potential importance of these changes are discussed. 17 references, 2 figures.

  12. Rocks, soils, and water quality. Relationships and implications for effects of acid precipitation on surface water in the northeastern United States

    SciTech Connect

    Kaplan, E.; Thode, H.C. Jr.; Protas, A.

    1981-05-01

    Distribution of rocks and soils in Northeast counties were investigated for the degree to which they influence pH and alkalinity in surface waters. Using 283 counties, path analysis resulted in two models of equivalent explanatory power. Each model indicated the importance of both rocks and soils as determinants of pH and alkalinity in surface waters, and as important factors in the sensitivity of natural waters to acidification from acid precipitation. Previous studies have emphasized the importance of bedrock geology, at the expense of knowledge about soils, in an understanding of waters sensitive to the effects of acid precipitation. Our regional analysis found that rocks were contributors to the buffering capacity of surface water; however, the presence of a large percentage of alfisol soils better indicates locations of waters with higher levels of alkalinity, and thus of greater resistance to effects of acid rain.

  13. Biomass of algae growth on natural water medium.

    PubMed

    Ramaraj, Rameshprabu; Tsai, David Dah-Wei; Chen, Paris Honglay

    2015-01-01

    Algae are the dominant primary producers in aquatic ecosystems. Since algae are highly varied group organisms, which have important functions in ecosystem, and their biomass is an essential biological resource. Currently, algae have been applied increasingly to diverse range of biomass applications. Therefore, this study was aimed to investigate the ecological algae features of microalgal production by natural medium, ecological function by lab scale of the symbiotic reactor which is imitated nature ecosystem, and atmospheric CO2 absorption that was related the algal growth of biomass to understand algae in natural water body better. Consequently, this study took advantages of using the unsupplemented freshwater natural medium to produce microalgae. Algal biomass by direct measurement of total suspended solids (TSS) and volatile suspended solids (VSS) resulted as 0.14g/L and 0.08g/L respectively. The biomass measurements of TSS and VSS are the sensible biomass index for algae production. The laboratory results obtained in the present study proved the production of algae by the natural water medium is potentially feasible.

  14. The evolution of a mining lake - From acidity to natural neutralization.

    PubMed

    Sienkiewicz, Elwira; Gąsiorowski, Michał

    2016-07-01

    Along the border of Poland and Germany (central Europe), many of the post-mining lakes have formed "an anthropogenic lake district". This study presents the evolution of a mining lake ecosystem (TR-33) based on subfossil phyto- and zooplankton, isotopic data (δ(13)C, δ(15)N), elemental analyses of organic carbon and nitrogen (C/N ratio and TOC) and sedimentological analyses. Recently, lake TR-33 became completely neutralized from acidification and an increase in eutrophication began a few years ago. However, the lake has never been neutralized by humans; only natural processes have influenced the present water quality. From the beginning of the existence of the lake (1920s) to the present, we can distinguish four stages of lake development: 1) very shallow reservoir without typical lake sediments but with a sand layer containing fine lignite particles and very poor diatom and cladoceran communities; 2) very acidic, deeper water body with increasing frequencies of phyto- and zooplankton; 3) transitional period (rebuilding communities of diatoms and Cladocera), meaning a deep lake with benthic and planktonic fauna and flora with wide ecological tolerances; and 4) a shift to circumneutral conditions with an essential increase in planktonic taxa that prefer more fertile waters (eutrophication). In the case of lake TR-33, this process of natural neutralization lasted approximately 23years.

  15. Microorganisms in subterranean acidic waters within Europe's deepest metal mine.

    PubMed

    Kay, Catherine M; Haanela, Anu; Johnson, D Barrie

    2014-11-01

    The Pyhäsalmi mine, central Finland, has operated as a deep metal mine since 1967. It currently reaches a depth of almost 1500 m, making it the deepest mining operation in Europe. Around 900,000 m(3) of metal-rich, extremely acidic water are pumped out of the mine each year. The near constant air temperature of ∼ 24 °C together with exposure of sulfidic rock surfaces to air and water, have created an environment that is highly suitable for colonization by acidophilic mineral-oxidizing microorganisms. Using a combined cultivation-dependent and molecular approach, indigenous bacteria in waters at two depths within the mine, and of an acid streamer sample were identified and isolated. Iron-oxidizing chemolithotrophs (Acidithiobacillus and Leptospirillum spp., and "Ferrovum myxofaciens" were the most abundant bacteria in mine water samples, whereas the acid streamer community contained a greater proportion of heterotrophic acidophiles (Ferrimicrobium acidiphilum and a gammaproteobacterium related to Metallibacterium scheffleri). The most abundant isolates obtained from both water and streamer samples were all strains of Acidithiobacillus Group IV, a proposed separate species of iron-oxidizing acidithiobacilli that has not yet been classified as such. Archaea were also detected in water and streamer samples using molecular methods, but most were not identified and no isolates were obtained.

  16. Limitations in the use of commercial humic acids in water and soil research

    USGS Publications Warehouse

    Malcolm, R.L.; MacCarthy, P.

    1986-01-01

    Seven samples of commercial "humic acids", purchased from five different suppliers, were studied, and their characteristics were compared with humic and fulvic acids isolated from streams, soils, peat, leonardite, and a dopplerite sample. Cross-polarization and magic-angle spinning 13C NMR spectroscopy clearly shows pronounced differences between the commercial materials and all other samples. Elemental and infrared spectroscopic data do not show such clear-cut differences but can be used as supportive evidence, with the 13C NMR data, to substantiate the above distinctions. As a result of these differences and due to the general lack of information relating to the source, method of isolation, or other pretreatment of the commercial materials, these commercial products are not considered to be appropriate for use as analogues of true soil and water humic substances, in experiments designed to evaluate the nature and reactivity of humic substances in natural waters and soils.

  17. Photodegradation of triazine herbicides in aqueous solutions and natural waters.

    PubMed

    Evgenidou, E; Fytianos, K

    2002-10-23

    The photodegradation of three triazines, atrazine, simazine, and prometryn, in aqueous solutions and natural waters using UV radiation (lambda > 290 nm) has been studied. Experimental results showed that the dark reactions were negligible. The rate of photodecomposition in aqueous solutions depends on the nature of the triazines and follows first-order kinetics. In the case of the use of hydrogen peroxide and UV radiation, a synergistic effect was observed. The number of photodegradation products detected, using FIA/MS and FIA/MS/MS techniques, suggests the existence of various degradation routes resulting in complex and interconnected pathways. PMID:12381128

  18. Probing fatty acid metabolism in bacteria, cyanobacteria, green microalgae and diatoms with natural and unnatural fatty acids.

    PubMed

    Beld, Joris; Abbriano, Raffaela; Finzel, Kara; Hildebrand, Mark; Burkart, Michael D

    2016-04-01

    In both eukaryotes and prokaryotes, fatty acid synthases are responsible for the biosynthesis of fatty acids in an iterative process, extending the fatty acid by two carbon units every cycle. Thus, odd numbered fatty acids are rarely found in nature. We tested whether representatives of diverse microbial phyla have the ability to incorporate odd-chain fatty acids as substrates for their fatty acid synthases and their downstream enzymes. We fed various odd and short chain fatty acids to the bacterium Escherichia coli, cyanobacterium Synechocystis sp. PCC 6803, green microalga Chlamydomonas reinhardtii and diatom Thalassiosira pseudonana. Major differences were observed, specifically in the ability among species to incorporate and elongate short chain fatty acids. We demonstrate that E. coli, C. reinhardtii, and T. pseudonana can produce longer fatty acid products from short chain precursors (C3 and C5), while Synechocystis sp. PCC 6803 lacks this ability. However, Synechocystis can incorporate and elongate longer chain fatty acids due to acyl-acyl carrier protein synthetase (AasS) activity, and knockout of this protein eliminates the ability to incorporate these fatty acids. In addition, expression of a characterized AasS from Vibrio harveyii confers a similar capability to E. coli. The ability to desaturate exogenously added fatty acids was only observed in Synechocystis and C. reinhardtii. We further probed fatty acid metabolism of these organisms by feeding desaturase inhibitors to test the specificity of long-chain fatty acid desaturases. In particular, supplementation with thia fatty acids can alter fatty acid profiles based on the location of the sulfur in the chain. We show that coupling sensitive gas chromatography mass spectrometry to supplementation of unnatural fatty acids can reveal major differences between fatty acid metabolism in various organisms. Often unnatural fatty acids have antibacterial or even therapeutic properties. Feeding of short

  19. Probing fatty acid metabolism in bacteria, cyanobacteria, green microalgae and diatoms with natural and unnatural fatty acids.

    PubMed

    Beld, Joris; Abbriano, Raffaela; Finzel, Kara; Hildebrand, Mark; Burkart, Michael D

    2016-04-01

    In both eukaryotes and prokaryotes, fatty acid synthases are responsible for the biosynthesis of fatty acids in an iterative process, extending the fatty acid by two carbon units every cycle. Thus, odd numbered fatty acids are rarely found in nature. We tested whether representatives of diverse microbial phyla have the ability to incorporate odd-chain fatty acids as substrates for their fatty acid synthases and their downstream enzymes. We fed various odd and short chain fatty acids to the bacterium Escherichia coli, cyanobacterium Synechocystis sp. PCC 6803, green microalga Chlamydomonas reinhardtii and diatom Thalassiosira pseudonana. Major differences were observed, specifically in the ability among species to incorporate and elongate short chain fatty acids. We demonstrate that E. coli, C. reinhardtii, and T. pseudonana can produce longer fatty acid products from short chain precursors (C3 and C5), while Synechocystis sp. PCC 6803 lacks this ability. However, Synechocystis can incorporate and elongate longer chain fatty acids due to acyl-acyl carrier protein synthetase (AasS) activity, and knockout of this protein eliminates the ability to incorporate these fatty acids. In addition, expression of a characterized AasS from Vibrio harveyii confers a similar capability to E. coli. The ability to desaturate exogenously added fatty acids was only observed in Synechocystis and C. reinhardtii. We further probed fatty acid metabolism of these organisms by feeding desaturase inhibitors to test the specificity of long-chain fatty acid desaturases. In particular, supplementation with thia fatty acids can alter fatty acid profiles based on the location of the sulfur in the chain. We show that coupling sensitive gas chromatography mass spectrometry to supplementation of unnatural fatty acids can reveal major differences between fatty acid metabolism in various organisms. Often unnatural fatty acids have antibacterial or even therapeutic properties. Feeding of short

  20. Rapid magnetic-mediated solid-phase extraction and pre-concentration of selected endocrine disrupting chemicals in natural waters by poly(divinylbenzene-co-methacrylic acid) coated Fe3O4 core-shell magnetite microspheres for their liquid chromatography-tandem mass spectrometry determination.

    PubMed

    Li, Qingling; Lam, Michael H W; Wu, Rudolf S S; Jiang, Biwang

    2010-02-19

    A new Fe(3)O(4)/poly(divinylbenzene-co-methacrylic acid) core-shell magnetite microspheric material have been successfully developed as magnetic-mediated solid-phase extraction micro-particle sorbent in dispersion mode (MM-SPE-MP) for the determination of selected estrogenic endocrine disrupting chemicals (EDCs), namely: estrone (E1), 17beta-estradiol (E2), estriol (E3), 17alpha-ethynylestradiol (EE2) and bisphenol-A (BPA), in natural water, via quantification by HPLC tandem mass spectrometry. The magnetite Fe(3)O(4) core of this MM-SPE-MP sorbent was fabricated by a solvothermal approach and the thin layer of amphipolar poly(divinylbenzene-co-methacrylic acid) (pDVB-MAA) coating was established via suspension polymerization. The resultant core-shell MM-SPE-MP sorbent material was characterized by electron microscopy, X-ray diffraction and Fourier-transformed infrared spectroscopy. Particle size distribution of the core-shell microspheres was within the range 300-700 nm in diameter and the thickness of the pDVB-MAA coating was ca. 10nm. This magnetite microspheric material can be easily dispersed in aqueous samples and retrieved by the application of external magnetic field via a small piece of permanent magnet. The MM-SPE-MP process for the selected estrogenic EDCs involved the dispersion of the core-shell microspheric sorbent in water samples with sonication, followed by magnetic aided retrieval of the sorbent and solvent (methanol) desorption of extracted EDCs for LC-MS/MS analysis. Partition equilibrium for all the selected EDCs onto this MM-SPE-MP sorbent was achieved within 15 min. Recoveries of the EDCs were in ranges of 56-111%. Analytes with smaller K(OW) value showed relatively lower recovery (and relatively longer equilibration time for partitioning). Method detection limits achieved were found to be 1-36 pg ml(-1) (n=3), while the repeatability was 6-34% (p<0.05, n=3). This work demonstrates the usefulness of MM-SPE-MP in the rapid and highly sensitive

  1. Water Resources and Natural Gas Production from the Marcellus Shale

    USGS Publications Warehouse

    Soeder, Daniel J.; Kappel, William M.

    2009-01-01

    The Marcellus Shale is a sedimentary rock formation deposited over 350 million years ago in a shallow inland sea located in the eastern United States where the present-day Appalachian Mountains now stand (de Witt and others, 1993). This shale contains significant quantities of natural gas. New developments in drilling technology, along with higher wellhead prices, have made the Marcellus Shale an important natural gas resource. The Marcellus Shale extends from southern New York across Pennsylvania, and into western Maryland, West Virginia, and eastern Ohio (fig. 1). The production of commercial quantities of gas from this shale requires large volumes of water to drill and hydraulically fracture the rock. This water must be recovered from the well and disposed of before the gas can flow. Concerns about the availability of water supplies needed for gas production, and questions about wastewater disposal have been raised by water-resource agencies and citizens throughout the Marcellus Shale gas development region. This Fact Sheet explains the basics of Marcellus Shale gas production, with the intent of helping the reader better understand the framework of the water-resource questions and concerns.

  2. Natural organic matter and DBP formation potential in Alaskan water supplies.

    PubMed

    White, Daniel M; Garland, D Sarah; Narr, Jasprit; Woolard, Craig R

    2003-02-01

    Disinfection by-products (DBP) are formed when natural organic matter (NOM) in water reacts with a disinfectant, usually chlorine. DBPs are a health risk element and regulated under the Safe Drinking Water Act. A study was conducted to evaluate the characteristics of NOM that contribute to DBPs in 17 different drinking water systems in Alaska. In order to determine the nature of the organic matter contributing to DBPs, DBP formation potential was compared with standard water quality parameters such as UV-254, color and dissolved organic carbon (DOC), as well as pyrolysis-gas chromatography/mass spectrometry (GC/MS). Results showed strong correlations between UV-254 and DBP formation potential for all waters studied. DOC, on the other hand, was less strongly correlated to DBP formation potential. Unlike previous studies, the total trihalomethane and haloacetic acid formation potentials were equal on a mass concentration basis for the waters studied. Pyrolysis-GC/MS indicated that NOM contributing to DBPs were primarily phenolic compounds. This finding was consistent with previous studies; however, unlike other studies, no correlation was found between aliphatic compounds in the raw waters and DBP formation potential. PMID:12531277

  3. Using naturally occurring radionuclides to determine drinking water age in a community water system

    DOE PAGESBeta

    Waples, James T.; Bordewyk, Jason K.; Knesting, Kristina M.; Orlandini, Kent A.

    2015-07-22

    Drinking water quality in a community water system is closely linked to the age of water from initial treatment to time of delivery. However, water age is difficult to measure with conventional chemical tracers; particularly in stagnant water, where the relationship between disinfectant decay, microbial growth, and water age is poorly understood. Using radionuclides that were naturally present in source water, we found that measured activity ratios of 90Y/90Sr and 234Th/238U in discrete drinking water samples of known age accurately estimated water age up to 9 days old (σest: ± 3.8 h, P < 0.0001, r2 = 0.998, n =more » 11) and 25 days old (σest: ± 13.3 h, P < 0.0001, r2 = 0.996, n = 12), respectively. Moreover, 90Y-derived water ages in a community water system (6.8 × 104 m3 d–1 capacity) were generally consistent with water ages derived from an extended period simulation model. Radionuclides differ from conventional chemical tracers in that they are ubiquitous in distribution mains and connected premise plumbing. The ability to measure both water age and an analyte (e.g., chemical or microbe) in any water sample at any time allows for new insight into factors that control drinking water quality.« less

  4. Using Naturally Occurring Radionuclides To Determine Drinking Water Age in a Community Water System.

    PubMed

    Waples, James T; Bordewyk, Jason K; Knesting, Kristina M; Orlandini, Kent A

    2015-08-18

    Drinking water quality in a community water system is closely linked to the age of water from initial treatment to time of delivery. However, water age is difficult to measure with conventional chemical tracers; particularly in stagnant water, where the relationship between disinfectant decay, microbial growth, and water age is poorly understood. Using radionuclides that were naturally present in source water, we found that measured activity ratios of (90)Y/(90)Sr and (234)Th/(238)U in discrete drinking water samples of known age accurately estimated water age up to 9 days old (σest: ± 3.8 h, P < 0.0001, r(2) = 0.998, n = 11) and 25 days old (σest: ± 13.3 h, P < 0.0001, r(2) = 0.996, n = 12), respectively. Moreover, (90)Y-derived water ages in a community water system (6.8 × 10(4) m(3) d(-1) capacity) were generally consistent with water ages derived from an extended period simulation model. Radionuclides differ from conventional chemical tracers in that they are ubiquitous in distribution mains and connected premise plumbing. The ability to measure both water age and an analyte (e.g., chemical or microbe) in any water sample at any time allows for new insight into factors that control drinking water quality.

  5. Water-lactose behavior as a function of concentration and presence of lactic acid in lactose model systems.

    PubMed

    Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani

    2015-12-01

    The presence of high amounts of lactic acid in acid whey restricts its ability to be further processed because lactose appears to remain in its amorphous form. A systematic study is lacking in this regard especially during the concentration step. Hence, the main aim of the study was to establish the structure and behavior of water molecules surrounding lactose in the presence of 1% (wt/wt) lactic acid at a concentration up to 50% (wt/wt). Furthermore, the crystallization nature of freeze-dried lactose with or without lactic acid was established using differential scanning calorimetry and Fourier transform infrared spectroscopy. Two mechanisms were proposed to describe the behavior of water molecules around lactose molecules during the concentration of pure lactose and lactose solutions with lactic acid. Pure lactose solution exhibited a water evaporation enthalpy of ~679 J·g(-1), whereas lactose+ lactic acid solution resulted in ~965 J·g(-1) at a 50% (wt/wt) concentration. This indicates a greater energy requirement for water removal around lactose in the presence of lactic acid. Higher crystallization temperatures were observed with the presence of lactic acid, indicating a delay in crystallization. Furthermore, less crystalline lactose (~12%) was obtained in the presence of lactic acid, indicating high amorphous nature compared with pure lactose where ~50% crystallinity was obtained. The Fourier transform infrared spectra revealed that the strong hydration layer consisting lactic acid and H3O(+) ions surrounded lactose molecules via strong H bonds, which restricted water mobility, induced a change in structure of lactose, or both, creating unfavorable conditions for lactose crystallization. Thus, partial or complete removal of lactic acid from acid whey may be the first step toward improving the ability of acid whey to be processed. PMID:26476948

  6. Water-lactose behavior as a function of concentration and presence of lactic acid in lactose model systems.

    PubMed

    Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani

    2015-12-01

    The presence of high amounts of lactic acid in acid whey restricts its ability to be further processed because lactose appears to remain in its amorphous form. A systematic study is lacking in this regard especially during the concentration step. Hence, the main aim of the study was to establish the structure and behavior of water molecules surrounding lactose in the presence of 1% (wt/wt) lactic acid at a concentration up to 50% (wt/wt). Furthermore, the crystallization nature of freeze-dried lactose with or without lactic acid was established using differential scanning calorimetry and Fourier transform infrared spectroscopy. Two mechanisms were proposed to describe the behavior of water molecules around lactose molecules during the concentration of pure lactose and lactose solutions with lactic acid. Pure lactose solution exhibited a water evaporation enthalpy of ~679 J·g(-1), whereas lactose+ lactic acid solution resulted in ~965 J·g(-1) at a 50% (wt/wt) concentration. This indicates a greater energy requirement for water removal around lactose in the presence of lactic acid. Higher crystallization temperatures were observed with the presence of lactic acid, indicating a delay in crystallization. Furthermore, less crystalline lactose (~12%) was obtained in the presence of lactic acid, indicating high amorphous nature compared with pure lactose where ~50% crystallinity was obtained. The Fourier transform infrared spectra revealed that the strong hydration layer consisting lactic acid and H3O(+) ions surrounded lactose molecules via strong H bonds, which restricted water mobility, induced a change in structure of lactose, or both, creating unfavorable conditions for lactose crystallization. Thus, partial or complete removal of lactic acid from acid whey may be the first step toward improving the ability of acid whey to be processed.

  7. Droplet freezing experiments in stearic acid-water emulsions, role of the droplet-medium interface

    SciTech Connect

    Cordiez, J.P.; Grange, G.; Mutaftschiev, B.

    1982-02-01

    Droplets of stearic acid emulsions in water, stabilized with cationic or anionic emulsifiers, undergoing freezing-melting cycles with constant temperature scanning rate, freeze as monocrystals and independently from one another, even when visible clustering takes place. The study of the nucleation kinetics by differential scanning calorimetry shows that nucleation threshold (critical undercooling) depends on the nature of the emulsifier, adsorbed at the droplet-medium interface. 30 references.

  8. Transformation of acidic poorly water soluble drugs into ionic liquids.

    PubMed

    Balk, Anja; Wiest, Johannes; Widmer, Toni; Galli, Bruno; Holzgrabe, Ulrike; Meinel, Lorenz

    2015-08-01

    Poor water solubility of active pharmaceutical ingredients (API) is a major challenge in drug development impairing bioavailability and therapeutic benefit. This study is addressing the possibility to tailor pharmaceutical and physical properties of APIs by transforming these into tetrabutylphosphonium (TBP) salts, including the generation of ionic liquids (IL). Therefore, poorly water soluble acidic APIs (Diclofenac, Ibuprofen, Ketoprofen, Naproxen, Sulfadiazine, Sulfamethoxazole, and Tolbutamide) were converted into TBP ILs or low melting salts and compared to the corresponding sodium salts. Free acids and TBP salts were characterized by NMR and IR spectroscopy, DSC and XRPD, DVS and dissolution rate measurements, release profiles, and saturation concentration measurements. TBP salts had lower melting points and glass transition temperatures and dissolution rates were improved up to a factor of 1000 as compared to the corresponding free acid. An increase in dissolution rates was at the expense of increased hygroscopicity. In conclusion, the creation of TBP ionic liquids or solid salts from APIs is a valuable concept addressing dissolution and solubility challenges of poorly water soluble acidic compounds. The data suggested that tailor-made counterions may substantially expand the formulation scientist's armamentarium to meet challenges of poorly water soluble drugs.

  9. Disinfection of water in recirculating aquaculture systems with peracetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) has become a favoured alternative to chlorination in the disinfection of municipal waste water in recent years. It is also commonly used in the food industry as a disinfectant. Based on PAA concentration, the disulfide linkage in enzymes and proteins of microorganisms can be bro...

  10. NEUROTOXICITY PRODUCED BY DIBROMOACETIC ACID IN DRINKING WATER OF RATS.

    EPA Science Inventory

    This manuscript examines the neurotoxic potential of a commonly found disinfection by-product (DBP), dibromoacetic acid (DBA). While the Safe Drinking Water Act requires evaluation of DBPs for noncancer health effects, surprisingly few have been tested for neurotoxicity. Rats e...

  11. Evaporation kinetics of acetic acid-water solutions

    NASA Astrophysics Data System (ADS)

    Duffey, K.; Wong, N.; Saykally, R.; Cohen, R. C.

    2012-12-01

    The transport of water molecules across vapor-liquid interfaces in the atmosphere is a crucial step in the formation and evolution of cloud droplets. Despite decades of study, the effects of solutes on the mechanism and rate of evaporation and condensation remain poorly characterized. The present work aims to determine the effect of atmospherically-relevant solutes on the evaporation rate of water. In our experiments, we create a train of micron-sized droplets and measure their temperature via Raman thermometry as they undergo evaporation without condensation. Analysis of the cooling rate yields the evaporation coefficient (γ). Previous work has shown that inorganic salts have little effect on γ, with surface-adsorbing anions causing a slight reduction in the coefficient from that measured for pure water. Organic acids are ubiquitous in aqueous aerosol and have been shown to disrupt the surface structure of water. Here we describe measurements of the evaporation rate of acetic acid solutions, showing that acetic acid reduces γ to a larger extent than inorganic ions, and that γ decreases with increasing acetic acid concentration.

  12. Biodegradable water absorbent synthesized from bacterial poly(amino acid)s.

    PubMed

    Kunioka, Masao

    2004-03-15

    Biodegradable hydrogels prepared by gamma-irradiation from microbial poly(amino acid)s have been studied. pH-Sensitive hydrogels were prepared by the gamma-irradiation of poly(gamma-glutamic acid) (PGA) produced by Bacillus subtilis and poly(epsilon-lysine) (PL) produced by Streptomyces albulus in aqueous solutions. When the gamma-irradiation dose was 19 kGy or more, and the concentration of PGA in water was 2 wt.-% or more, transparent hydrogels could be produced. For the 19 kGy dose, the produced hydrogel was very weak, however, the specific water content (wt. of absorbed water/wt. of dry hydrogel) of this PGA hydrogel was approximately 3,500. The specific water content decreased to 200, increasing when the gamma-irradiation dose was over 100 kGy. Under acid conditions or upon the addition of electrolytes, the PGA hydrogels shrunk. The PGA hydrogel was pH-sensitive and the change in the volume of the hydrogel depended on the pH value outside the hydrogel in the swelling medium. This PGA hydrogel was hydrodegradable and biodegradable. A new novel purifier reagent (coagulant), made from the PGA hydrogels, for contaminated turbid water has been found and developed by Japanese companies. A very small amount of this coagulant (only 2 ppm in turbid water) with poly(aluminum chloride) can be used for the purification of turbid water. A PL aqueous solution also can change into a hydrogel by gamma-irradiation. The specific water content of the PL hydrogel ranged from 20 to 160 depending on the preparation conditions. Under acid conditions, the PL hydrogel swelled because of the ionic repulsion of the protonated amino groups in the PL molecules. The rate of enzymatic degradation of the respective PL hydrogels by a neutral protease was much faster than the rate of simple hydrolytic degradation. PMID:15468223

  13. A new method of calculating electrical conductivity with applications to natural waters

    USGS Publications Warehouse

    McCleskey, R. Blaine; Nordstrom, D. Kirk; Ryan, Joseph N.; Ball, James W.

    2012-01-01

    A new method is presented for calculating the electrical conductivity of natural waters that is accurate over a large range of effective ionic strength (0.0004–0.7 mol kg-1), temperature (0–95 °C), pH (1–10), and conductivity (30–70,000 μS cm-1). The method incorporates a reliable set of equations to calculate the ionic molal conductivities of cations and anions (H+, Li+, Na+, K+, Cs+, NH4+, Mg2+, Ca2+, Sr2+, Ba2+, F-, Cl-, Br-, SO42-, HCO3-, CO32-, NO3-, and OH-), environmentally important trace metals (Al3+, Cu2+, Fe2+, Fe3+, Mn2+, and Zn2+), and ion pairs (HSO4-, NaSO4-, NaCO3-, and KSO4-). These equations are based on new electrical conductivity measurements for electrolytes found in a wide range of natural waters. In addition, the method is coupled to a geochemical speciation model that is used to calculate the speciated concentrations required for accurate conductivity calculations. The method was thoroughly tested by calculating the conductivities of 1593 natural water samples and the mean difference between the calculated and measured conductivities was -0.7 ± 5%. Many of the samples tested were selected to determine the limits of the method and include acid mine waters, geothermal waters, seawater, dilute mountain waters, and river water impacted by municipal waste water. Transport numbers were calculated and H+, Na+, Ca2+, Mg2+, NH4+, K+, Cl-, SO42-, HCO3-, CO32-, F-, Al3+, Fe2+, NO3-, and HSO4- substantially contributed (>10%) to the conductivity of at least one of the samples. Conductivity imbalance in conjunction with charge imbalance can be used to identify whether a cation or an anion measurement is likely in error, thereby providing an additional quality assurance/quality control constraint on water analyses.

  14. Simulations of acid dissociation constants of polyprotic acids in near-critical and supercritical water.

    PubMed

    Halstead, Simon J; An, Pengna

    2013-12-01

    This paper reports a molecular dynamics study on the dissociation of sulfuric acid and phosphoric acid in near-critical and supercritical water. pK(a) is known to vary as the temperature and pressure vary, and this variation has important implications for corrosion in supercritical water reaction vessels. This work uses the SPC/E water model and solutes based upon DFT calculations to examine both structural and thermodynamic properties of the dissociation processes. An increase in solute-solvent ordering is observed for larger charges, and this also corresponds to a lower rate of diffusion. All dissociation reactions become less favored with increasing temperature except pK(a1) for sulfuric acid which becomes significantly more favored until 748 K.

  15. Pathology of naturally occurring paratuberculosis in water buffaloes (Bubalus bubalis).

    PubMed

    Sivakumar, P; Tripathi, B N; Singh, N; Sharma, A K

    2006-07-01

    Gross and histologic lesions of paratuberculosis were studied in water buffaloes. Small intestines and associated mesenteric lymph nodes of 405 water buffaloes were examined. Of these, 20 animals having visible changes of intestinal thickening, mucosal corrugations, and enlargement of mesenteric lymph nodes exhibited histologic alteration characteristics of mild to moderate granulomatous inflammation. The histologic lesions observed in these animals were classified into 3 grades on the basis of type of cellular infiltration, granuloma formation, and presence of acid-fast bacilli. Grade-1 lesions observed in 8 animals were marked by the presence of scattered epithelioid macrophages amid large number of lymphocytes in the intestinal villi and in the paracortical regions of the associated mesenteric lymph nodes. Another 8 animals classified under grade-2 revealed microgranulomas, infiltration with a larger number of epithelioid macrophages besides lymphocytes in the intestinal villi, and granulomas in the mesenteric lymph nodes. Grade-3 lesions observed in 4 animals were characterized by the presence of epithelioid granulomas and giant cells in the intestines and the mesenteric lymph nodes. The Ziehl-Neelsen's stained tissue sections revealed acid-fast bacilli in grade-3 and -2 animals and acid-fast granular debris in grade-1 animals. Among these 20 buffaloes, 14 (70%) were positive in the IS900 specific polymerase chain reaction and 6 (30%) were positive in the bacterial culture.

  16. The optical nature of methylsuccinic acid in human urine

    NASA Technical Reports Server (NTRS)

    Zeitman, B.; Lawless, J. G.

    1975-01-01

    Methylsuccinic acid was isolated from human urine, derivatized as the di-S-(+)-2-butyl ester, and analyzed using a gas chromatographic system capable of separating the enantiomers of the derivative. The R-(+)-isomer was found to be present. Methylsuccinic acid is potentially important as a criterion for abiogenicity, having been obtained as a racemic mixture from sources known to be abiotic.

  17. Modeling description and spectroscopic evidence of surface acid-base properties of natural illites.

    PubMed

    Liu, W

    2001-12-01

    The acid-base properties of natural illites from different areas were studied by potentiometric titrations. The acidimetric supernatant was regarded as the system blank to calculate the surface site concentration due to consideration of substrate dissolution during the prolonged acidic titration. The following surface complexation model could give a good interpretation of the surface acid-base reactions of the aqueous illites:

  18. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  19. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  20. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  1. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  2. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple... (including berries) may be added within the limitations of § 24.246 to juice or wine in order to correct natural deficiencies; however, no acid may be added to juice or wine which is ameliorated to...

  3. Nocturnal water storage in plants having Crassulacean acid metabolism.

    PubMed

    Lüttge, U

    1986-06-01

    Measurements of water uptake and transpiration, during the dark period of plants having Crassulacean acid metabolism (CAM) allow calculation of leaf-volume changes (ΔV). Nocturnal leaf-volume changes of CAM plants have also been reported in the literature on the basis of waterdisplacement measurements. A third way of estimation is from measurements of turgor changes and cellular water-storage capacity using the pressure probe, cytomorphometry and the Scholander pressure chamber. An extension of the interpretation of results reported in the literature shows that for leaf succulent CAM plants the three different approaches give similar values of ΔV ranging between 2.3 and 10.7% (v/v). It is evident that nocturnal malic-acid accumulation osmotically drives significant water storage in CAM leaf tissue. PMID:24232034

  4. Innovative Treatment Technologies for Natural Waters and Wastewaters

    SciTech Connect

    Childress, Amy E.

    2011-07-01

    The research described in this report focused on the development of novel membrane contactor processes (in particular, forward osmosis (FO), pressure retarded osmosis (PRO), and membrane distillation (MD)) in low energy desalination and wastewater treatment applications and in renewable energy generation. FO and MD are recently gaining national and international attention as viable, economic alternatives for removal of both established and emerging contaminants from natural and process waters; PRO is gaining worldwide attention as a viable source of renewable energy. The interrelationship of energy and water are at the core of this study. Energy and water are inextricably bound; energy usage and production must be considered when evaluating any water treatment process for practical application. Both FO and MD offer the potential for substantial energy and resource savings over conventional treatment processes and PRO offers the potential for renewable energy or energy offsets in desalination. Combination of these novel technologies with each other, with existing technologies (e.g., reverse osmosis (RO)), and with existing renewable energy sources (e.g., salinity gradient solar ponds) may enable much less expensive water production and also potable water production in remote or distributed locations. Two inter-related projects were carried out in this investigation. One focused on membrane bioreactors for wastewater treatment and PRO for renewable energy generation; the other focused on MD driven by a salinity gradient solar pond.

  5. Screening of Natural Waters for Viruses Which Infect Chlorella Cells

    PubMed Central

    Yamada, Takashi; Higashiyama, Takanobu; Fukuda, Takao

    1991-01-01

    By using a plaque assay with the unicellular green alga Chlorella sp. strain NC64A as a host, viruses were screened from natural pond waters collected in Kyoto and Higashi-Hiroshima, Japan. From some samples tested, two kinds of plaques, large (φ = 6 to 10 mm) and small (φ = 2 to 3 mm), were detected with various frequencies. The frequency of plaques in each of the water sources was seasonal; generally, it reached a peak value (8,000 PFU/ml) in May and gradually decreased to the limit of detection (<1) in November before increasing again in early spring. Electron microscopy revealed that the purified and negatively stained viruses were very large (125 to 200 nm) icosahedral particles. The genome isolated from these particles was always a linear double-stranded DNA of 340 to 370 kbp. Electrophoresis patterns of the DNA fragments produced by digestion with restriction enzymes differed considerably from plaque to plaque, even for plaques from the same water source. However, Southern hybridization showed strong homology among all of the virus DNAs tested, indicating relatedness of those viruses. A possible use of the Chlorella virus assay system to monitor the natural population of algal cells and water quality is discussed. Images PMID:16348596

  6. Nature of the water/aromatic parallel alignment interactions.

    PubMed

    Mitoraj, Mariusz P; Janjić, Goran V; Medaković, Vesna B; Veljković, Dušan Ž; Michalak, Artur; Zarić, Snežana D; Milčić, Miloš K

    2015-01-30

    The water/aromatic parallel alignment interactions are interactions where the water molecule or one of its O-H bonds is parallel to the aromatic ring plane. The calculated energies of the interactions are significant, up to ΔE(CCSD)(T)(limit) = -2.45 kcal mol(-1) at large horizontal displacement, out of benzene ring and CH bond region. These interactions are stronger than CH···O water/benzene interactions, but weaker than OH···π interactions. To investigate the nature of water/aromatic parallel alignment interactions, energy decomposition methods, symmetry-adapted perturbation theory, and extended transition state-natural orbitals for chemical valence (NOCV), were used. The calculations have shown that, for the complexes at large horizontal displacements, major contribution to interaction energy comes from electrostatic interactions between monomers, and for the complexes at small horizontal displacements, dispersion interactions are dominant binding force. The NOCV-based analysis has shown that in structures with strong interaction energies charge transfer of the type π → σ*(O-H) between the monomers also exists.

  7. Removal of hexavalent chromium from estuarine waters by model substrates and natural sediments

    SciTech Connect

    Mayer, L.M.; Schick, L.L.

    1981-12-01

    Chromate removal from waters with a range of salinities (0-32%) was studied by using both model substrates, alumina and kaolinite, and natural estuarine sediments in order to determine possible effects of sediment on dissolved chromate in estuarine systems. The dependence of chromate removal on sediment concentrations (<1 g L/sup -1/) will be ineffective in removing dissolved chromate from the water column, though the reaction will be important in deposited sediments. Chromate removal is more effective in low- than high-salinity regimes. Removal by model substrates decreases monotonically with increasing salinity but shows a peak in the 0.1-1.0% range with estuarine sediments. This latter behavior shows similarity with the salinity dependence of chromate reduction by gallic acid, suggesting reductive adsorption by the estuarine sediments. Naturally occurring levels of phosphate ansilicate show negligible effect on chromate removal.

  8. Using AVIRIS In The NASA BAA Project To Evaluate The Impact Of Natural Acid Drainage On Colorado Watersheds

    NASA Technical Reports Server (NTRS)

    Hauff, Phoebe L.; Coulter, David W.; Peters, Douglas C.; Sares, Matthew A.; Prosh, Eric C.; Henderson, Frederick B., III; Bird, David

    2004-01-01

    The Colorado Geological Survey and the co-authors of this paper were awarded one of 15 NASA Broad Agency Announcement (BAA) grants in 2001. The project focuses on the use of hyperspectral remote sensing to map acid-generating minerals that affect water quality within a watershed, and to identify the relative contributions of natural and anthropogenic sources to that drainage. A further objective is to define the most cost-effective remote sensing instrument configuration for this application.

  9. Photolysis and biodegradation of selected resin acids in River Saale water, Germany.

    PubMed

    McMartin, Dena W; Headley, John V; Neu, Thomas R; Friesen, Duane A

    2003-01-01

    The River Saale is the Elbe's major tributary flowing through the state of Thuringia, Germany and receives organics inputs from several industrial facilities including pulp and paper mills. Resin acids constitute a major class of polar organics and environmental toxins derived primarily from pulp and paper processing of softwoods. Since wastewater treatment methods at pulp and paper mills are not always capable of removing the persistent resin acids prior to effluent discharge, alternative or complementary degradation methods may be required. Here, the facile photodegradation of four resin acids--abietic, dehydroabietic, isopimaric, and pimaric--was observed with pseudo-first-order kinetics when exposed to broad band and UV254-radiation. Further experimentation in rotating annular biofilm reactors with UV-exposed and unexposed River Saale water spiked with abietic and dehydroabietic acids indicated that photolysis is an effective pretreatment method for resin acid biodegradation. The bacterial toxicity of the aqueous resin acids solutions as measured with Microtox luminescence assays decreased with exposure time. Consequently, photo- and biodegradation of the resin acids did not generate any notable amounts of toxic intermediates and/or the intermediates formed were further degraded into compounds of lower toxicity than the parents. With tandem photo- and biological treatment at pulp and paper mills, as well as in-situ degradation by solar radiation and natural biofilms within the River Saale, resin acid inputs can be reduced in both concentration and toxicity to near undetectable levels with little or no ecological significance.

  10. Remediation studies of trace metals in natural and treated water using surface modified biopolymer nanofibers

    NASA Astrophysics Data System (ADS)

    Musyoka, Stephen Makali; Ngila, Jane Catherine; Mamba, Bhekie B.

    In this study, remediation results of trace metals in natural water and treated water using three functionalized nanofiber mats of cellulose and chitosan are reported. The nanofiber materials, packed in mini-columns, were employed for the remediation of five toxic trace metals (Cd, Pb, Cu, Cr and Ni) from natural water samples. Trace metals in real water samples were undetectable as the concentrations were lower than the instrument’s detection limits of 0.27 × 10-3 (Cd) and 4.2 × 10-2 (Pb) μg mL-1, respectively. However, after percolation through the functionalised biosorbents in cartridges, detectability of the metal ions was enhanced. The starting volume of the natural water sample was 100 mL, which was passed through a column containing the nanofibers sorbent and the retained metals eluted with 5 mL of 2.0 M nitric acid. The eluate was analyzed for metals concentrations. An enrichment factor of 20 for the metals was realized as a result of the pre-concentration procedure applied to handle the determination of the metals at trace levels. The order of remediation of the studied metals using the nanofibers was as follows: chitosan/PAM-g-furan-2,5-dione < cellulose-g-furan-2,5-dione < cellulose-g-oxolane-2,5-dione. The modified biopolymer nanofibers were able to adsorb trace metals from the river water and treated water, thereby confirming their capability of water purification. These materials are proposed as useful tools and innovative approach for improving the quality of drinking for those consumers in small scale households.

  11. The determination of specific forms of aluminum in natural water

    USGS Publications Warehouse

    Barnes, R.B.

    1975-01-01

    A procedure for analysis and pretreatment of natural-water samples to determine very low concentrations of Al is described which distinguishes the rapidly reacting equilibrium species from the metastable or slowly reacting macro ions and colloidal suspended material. Aluminum is complexed with 8-hydroxyquinoline (oxine), pH is adjusted to 8.3 to minimize interferences, and the aluminum oxinate is extracted with methyl isobutyl ketone (MIBK) prior to analysis by atomic absorption. To determine equilibrium species only, the contact time between sample and 8-hydroxyquinoline is minimized. The Al may be extracted at the sample site with a minimum of equipment and the MIBK extract stored for several weeks prior to atomic absorption analysis. Data obtained from analyses of 39 natural groundwater samples indicate that filtration through a 0.1-??m pore size filter is not an adequate means of removing all insoluble and metastable Al species present, and extraction of Al immediately after collection is necessary if only dissolved and readily reactive species are to be determined. An average of 63% of the Al present in natural waters that had been filtered through 0.1-??m pore size filters was in the form of monomeric ions. The total Al concentration, which includes all forms that passed through a 0.1-??m pore size filter, ranged 2-70 ??g/l. The concentration of Al in the form of monomeric ions ranged from below detection to 57 ??g/l. Most of the natural water samples used in this study were collected from thermal springs and oil wells. ?? 1975.

  12. Cox-2 inhibitory effects of naturally occurring and modified fatty acids.

    PubMed

    Ringbom, T; Huss, U; Stenholm, A; Flock, S; Skattebøl, L; Perera, P; Bohlin, L

    2001-06-01

    In the search for new cyclooxygenase-2 (COX-2) selective inhibitors, the inhibitory effects of naturally occurring fatty acids and some of their structural derivatives on COX-2-catalyzed prostaglandin biosynthesis were investigated. Among these fatty acids, linoleic acid (LA), alpha-linolenic acid (alpha-LNA), myristic acid, and palmitic acid were isolated from a CH(2)Cl(2) extract of the plant Plantago major by bioassay-guided fractionation. Inhibitory effects of other natural, structurally related fatty acids were also investigated: stearic acid, oleic acid, pentadecanoic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Further, the inhibitory effects of these compounds on COX-2- and COX-1-catalyzed prostaglandin biosynthesis was compared with the inhibition of some synthesized analogues of EPA and DHA with ether or thioether functions. The most potent COX-2-catalyzed prostaglandin biosynthesis inhibitor was all-(Z)-5-thia-8,11,14,17-eicosatetraenoic acid (2), followed by EPA, DHA, alpha-LNA, LA, (7E,11Z,14Z,17Z)-5-thiaeicosa-7,11,14,17-tetraenoic acid, all-(Z)-3-thia-6,9,12,15-octadecatetraenoic acid, and (5E,9Z,12Z,15Z,18Z)-3-oxaheneicosa-5,9,12,15,18-pentaenoic acid, with IC(50) values ranging from 3.9 to180 microM. The modified compound 2 and alpha-LNA were most selective toward COX-2, with COX-2/COX-1 ratios of 0.2 and 0.1, respectively. This study shows that several of the natural fatty acids as well as all of the semisynthetic thioether-containing fatty acids inhibited COX-2-catalyzed prostaglandin biosynthesis, where alpha-LNA and compound 2 showed selectivity toward COX-2. PMID:11421736

  13. Coupling reverse osmosis with electrodialysis to isolate natural organic matter from fresh waters.

    PubMed

    Koprivnjak, J F; Perdue, E M; Pfromm, P H

    2006-10-01

    Reverse osmosis (RO) has proven to be an effective method for the concentration of natural organic matter (NOM) from fresh waters, but an undesirable consequence of this process is the co-concentration of some inorganic solutes. Accordingly, current practice yields solutions of NOM that, upon desalting and freeze-drying, are converted into dry solids containing finely dispersed sulfuric acid and silicic acid (H(4)SiO(4)). These acids will contribute to the apparent carboxylic and phenolic contents of NOM, leading to an overestimation of both. NOM may also be chemically altered by sulfuric acid, which reacts strongly with many classes of organic compounds. The sulfur content and ash content of NOM will be elevated in the presence of sulfuric acid and H(4)SiO(4). The goal of this study is to develop and test a method in which the removal of water by RO is coupled with the removal of salts by electrodialysis (ED). Like RO, ED is a relatively mild treatment that enables the desalting of NOM solutions without subjecting those samples to conditions of extremely high or low pH. The end product of the coupled process is a desalted, concentrated liquid sample from which low-ash NOM can be obtained as a freeze-dried solid material. In this study, the efficacy of ED for desalting NOM is evaluated using concentrated synthetic river waters and actual concentrated (by RO) river waters. Under optimal operating conditions, both sulfate and silica can be largely removed from RO-concentrated solutions of riverine NOM with only an average loss of 3% of total organic carbon. PMID:16952387

  14. Extraction and analysis of trifluoroacetic Acid in environmental waters.

    PubMed

    Wujcik, C E; Cahill, T M; Seiber, J N

    1998-10-01

    Trifluoroacetic acid (TFA), a mildly phytotoxic compound, is a stable atmospheric breakdown product of HFC-134a, HCFC-123, and HCFC-124. An extraction and analytical method has been developed for the routine analysis of low ppt levels of TFA in aqueous samples. TFA can be quantitatively recovered from most environmental waters by an extraction procedure using a commercial anion-exchange disk. In saline samples (conductivity >620 μS), where the presence of competing anions interfered with recovery, a liquid-liquid extraction cleanup was necessary. After extraction of TFA from water, the dried disk was placed in a headspace vial containing 10% sulfuric acid in methanol and the vial sealed and then vortexed for 30 s. The sulfuric acid-methanol solution extracts trifluoroacetate anion (TFA) from the anion-exchange matrix and, when heated, quantitatively converts it to the methyl ester, which is then analyzed by automated headspace gas chromatography using electron capture or mass spectrometry detection. Several environmental samples in addition to laboratory spike solutions were successfully extracted and analyzed with this technique. Recoveries averaged 108.2% for reagent water spiked at levels from 53 to 2110 ng/L with relative standard deviations ranging from 0.3 to 8.4%. The instrument's limit of detection for TFA standard was 3.3 ng. The limit of quantitation for the extraction and analytical technique was 36 ng/L. Three water samples can be prepared for automated analysis in 20 min using this technique. PMID:21651243

  15. Mitigation of acid deposition: Liming of surface waters. Final report

    SciTech Connect

    Bartoshesky, J.; Price, R.; DeMuro, J.

    1989-05-01

    In recent years acid deposition has become a serious concern internationally. Scientific literature has documented the acidification of numerous lakes and streams in North America and Scandinavia resulting in the depletion or total loss of fisheries and other aquatic biota. Liming represents the only common corrective practice aimed specifically at remediating an affected acid receptor. This report reviews a range of liming technologies and liming materials, as well as the effect of surface-water liming on water quality and aquatic biota. As background to the liming discussion, the hydrologic cycle and the factors that make surface waters sensitive to acid deposition are also discussed. Finally, a brief review of some of the liming projects that have been conducted, or are currently in operation is presented, giving special emphasis to mitigation efforts in Maryland. Liming has been effectively used to counteract surface-water acidification in parts of Scandinavia, Canada, and the U.S. To date, liming has generally been shown to improve physical and chemical conditions and enhance the biological recovery of aquatic ecosystems affected by acidification.

  16. Buffer capacities of fresh water lakes sensitive to acid rain deposition

    SciTech Connect

    Faust, S.D.; McIntosh, A.

    1983-01-01

    The Van Slyke definition of buffer capacity, the increment of a strong base or strong acid that causes an incremental change in the pH value of water, is better than total alkalinity for defining a water's resistance to acid rain. This Van Slyke value, designated by beta, shows a peak at pH 6.3 for the bicarbonate-carbonate pair, indicating that the effect of acid rain on the pH and alkalinity of natural waters is not deleterious until this peak is traversed. A beta value of zero indicates a dead water with no capacity to neutralize acid. The beta values, pH and total alkalinity of lakes, reservoirs, and streams in New Jersey are given. Data clearly show that pH and alkalinity alone cannot determine buffer capacity. For example: Fairview Lake (pH of 5.5 and alkalinity of 10.2 mg per liter) has a beta value 11 times that of Clyde Potts Reservoir (pH of 7.3, alkalinity of 8.1 mg per liter). 3 references, 1 figure, 1 table.

  17. Sialic acid metabolism and sialyltransferases: natural functions and applications

    PubMed Central

    Li, Yanhong

    2012-01-01

    Sialic acids are a family of negatively charged monosaccharides which are commonly presented as the terminal residues in glycans of the glycoconjugates on eukaryotic cell surface or as components of capsular polysaccharides or lipooligosaccharides of some pathogenic bacteria. Due to their important biological and pathological functions, the biosynthesis, activation, transfer, breaking down, and recycle of sialic acids are attracting increasing attention. The understanding of the sialic acid metabolism in eukaryotes and bacteria leads to the development of metabolic engineering approaches for elucidating the important functions of sialic acid in mammalian systems and for large-scale production of sialosides using engineered bacterial cells. As the key enzymes in biosynthesis of sialylated structures, sialyltransferases have been continuously identified from various sources and characterized. Protein crystal structures of seven sialyltransferases have been reported. Wild-type sialyltransferases and their mutants have been applied with or without other sialoside biosynthetic enzymes for producing complex sialic acid-containing oligosaccharides and glycoconjugates. This mini-review focuses on current understanding and applications of sialic acid metabolism and sialyltransferases. PMID:22526796

  18. Perfluorooctanoic acid degradation in the presence of Fe(III) under natural sunlight.

    PubMed

    Liu, Dandan; Xiu, Zongming; Liu, Fei; Wu, Gang; Adamson, Dave; Newell, Charles; Vikesland, Peter; Tsai, Ah-Lim; Alvarez, Pedro J

    2013-11-15

    Due to the high bond dissociation energy (BDE) of CF bonds (116 kcal/mol), perfluorooctanoic acid (PFOA) is a highly recalcitrant pollutant. Herein, we demonstrate a novel method to decompose PFOA in the presence of sunlight and ferric iron (Fe(III)). Under such conditions, 97.8 ± 1.7% of 50 μM PFOA decomposed within 28 days into shorter-chain intermediates and fluoride (F(-)), with an overall defluorination extent of 12.7 ± 0.5%. No PFOA was removed under visible light, indicating that UV radiation is required for PFOA decomposition. Spectroscopic analysis indicates that the decomposition reaction is likely initiated by electron-transfer from PFOA to Fe(III), forming Fe(II) and an unstable organic carboxyl radical. An alternative mechanism for the formation of this organic radical involves hydroxyl radicals, detected by electron paramagnetic resonance (EPR). The observation that PFOA can be degraded by Fe(III) under solar irradiation provides mechanistic insight into a possibly overlooked natural attenuation process. Because Fe(III) is abundant in natural waters and sunlight is essentially free, this work represents a potentially important step toward the development of simple and inexpensive remediation strategies for PFOA-contaminated water.

  19. Amino acids, fatty acids and sterols profile of some marine organisms from Portuguese waters.

    PubMed

    Pereira, David M; Valentão, Patrícia; Teixeira, Natércia; Andrade, Paula B

    2013-12-01

    Marine organisms have been increasingly regarded as good sources of new drugs for human therapeutics and also as nutrients for human diet. The amino acids, fatty acids and sterols profiles of the widely consumed echinoderms Paracentrotus lividus Lamarck (sea urchin), Holothuria forskali Chiaje (sea cucumber), the gastropod molluscs Aplysia fasciata Poiret and Aplysia punctata Cuvier (sea hares), from Portuguese waters, were established by GC-MS analysis. Overall, 10 amino acids, 14 fatty acids and 4 sterols were determined. In general, all species presented the 10 amino acids identified, with the exceptions of H. forskali, in which no glycine, proline, trans-4-hydroxy-proline or phenylalanine were found, and of A. fasciata which did not contain proline. Unsaturated fatty acids were predominant compounds, with those from the ω-6 series, being in higher amounts than their ω-3 homologues, and cholesterol being the main sterol. The amino acids, fatty acids and sterols qualitative and quantitative composition of A. fasciata, A. punctata and H. forskali is reported here for the first time.

  20. A study of amino acid modifiers in guayule natural rubber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural rubber from the Hevea tree is a critical agricultural material vital to United States industry, medicine, and defense, yet the country is dependent on imports to meet domestic needs. Guayule, a desert shrub indigenous to the US, is under development as an alternative source of natural rubber...

  1. Emergency Response Planning to Reduce the Impact of Contaminated Drinking Water during Natural Disasters

    EPA Science Inventory

    Natural disasters can be devastating to local water supplies affecting millions of people. Disaster recovery plans and water industry collaboration during emergencies protect consumers from contaminated drinking water supplies and help facilitate the repair of public water system...

  2. Characterization of an organic acid analog model in Adirondack, New York, surface waters

    NASA Astrophysics Data System (ADS)

    Fakhraei, H.; Driscoll, C. T.

    2013-12-01

    Natural waters include a variety of organic matter that differs in composition and functional groups. Dissolved organic matter is important but difficult to characterize acidic and metal binding (e.g., Al) functional groups in chemical equilibrium models. In this study data from Adirondack Lake Survey were used to calibrate an organic acid analog model in order to quantify the influence of organic acids on surface water chemistry. The study sites in the Adirondack region of New York have diverse levels of dissolved organic carbon (DOC), used as a surrogate for organic acids. DOC in 55 Adirondack surface waters varies from 180 μmol C/l (in Little Echo Pond) to 1263 μmol C/l (in Sunday Pond). To reduce the variability inherited in the large raw data set, suite of mean observations was constructed by grouping and averaging measured data into pH intervals of 0.05 pH units from pH 4.15 to 7.3. A chemical equilibrium model, which includes major solutes in natural waters, was linked to an optimization algorithm (genetic algorithm) to calibrate a triprotic organic analog model which includes proton and aluminum binding by adjusting the dissociation constants and site density of DOC. The object of fitting procedure was to simultaneously minimize the discrepancy between observed and simulated pH, acid neutralizing capacity (ANC), organic monomeric aluminum and inorganic monomeric aluminum. A sensitivity analysis on calibrated values indicate that the speciation of the modeled solutes are most responsive to the dissociation constant of AlOrg= Al3+ + Org3- reaction (Org3- represents organic anion), the site density of DOC and the second H+ dissociation constant of the triprotic organic analog (i.e. H2Org- = 2H+ + Org3- reaction).

  3. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park: IV Acid-sulfate waters

    USGS Publications Warehouse

    Kirk, Nordstrom D.; Blaine, McCleskey R.; Ball, J.W.

    2009-01-01

    Many waters sampled in Yellowstone National Park, both high-temperature (30-94 ??C) and low-temperature (0-30 ??C), are acid-sulfate type with pH values of 1-5. Sulfuric acid is the dominant component, especially as pH values decrease below 3, and it forms from the oxidation of elemental S whose origin is H2S in hot gases derived from boiling of hydrothermal waters at depth. Four determinations of pH were obtained: (1) field pH at field temperature, (2) laboratory pH at laboratory temperature, (3) pH based on acidity titration, and (4) pH based on charge imbalance (at both laboratory and field temperatures). Laboratory pH, charge imbalance pH (at laboratory temperature), and acidity pH were in close agreement for pH ??10%, a selection process was used to compare acidity, laboratory, and charge balance pH to arrive at the best estimate. Differences between laboratory and field pH can be explained based on Fe oxidation, H2S or S2O3 oxidation, CO2 degassing, and the temperature-dependence of pK2 for H2SO4. Charge imbalances are shown to be dependent on a speciation model for pH values 350 mg/L Cl) decrease as the Cl- concentration increases from boiling which appears inconsistent with the hypothesis of H2S oxidation as a source of hydrothermal SO4. This trend is consistent with the alternate hypothesis of anhydrite solubility equilibrium. Acid-sulfate water analyses are occasionally high in As, Hg, and NH3 concentrations but in contrast to acid mine waters they are low to below detection in Cu, Zn, Cd, and Pb concentrations. Even concentrations of SO4, Fe, and Al are much lower in thermal waters than acid mine waters of the same pH. This difference in water chemistry may explain why certain species of fly larvae live comfortably in Yellowstone's acid waters but have not been observed in acid rock drainage of the same pH.

  4. Mass transfer and carbon isotope evolution in natural water systems

    USGS Publications Warehouse

    Wigley, T.M.L.; Plummer, L.N.; Pearson, F.J.

    1978-01-01

    This paper presents a theoretical treatment of the evolution of the carbon isotopes C13 and C14 in natural waters and in precipitates which derive from such waters. The effects of an arbitrary number of sources (such as dissolution of carbonate minerals and oxidation of organic material) and sinks (such as mineral precipitation, CO2 degassing and production of methane), and of equilibrium fractionation between solid, gas and aqueous phases are considered. The results are expressed as equations relating changes in isotopic composition to changes in conventional carbonate chemistry. One implication of the equations is that the isotopic composition of an aqueous phase may approach a limiting value whenever there are simultaneous inputs and outputs of carbonate. In order to unambiguously interpret isotopic data from carbonate precipitates and identify reactants and products in reacting natural waters, it is essential that isotopic changes are determined chiefly by reactant and product stoichiometry, independent of reaction path. We demonstrate that this is so by means of quantitative examples. The evolution equations are applied to: 1. (1) carbon-14 dating of groundwaters; 2. (2) interpretation of the isotopic composition of carbonate precipitates, carbonate cements and diagenetically altered carbonates; and 3. (3) the identification of chemical reaction stoichiometry. These applications are illustrated by examples which show the variation of ??C13 in solutions and in precipitates formed under a variety of conditions involving incongruent dissolution, CO2 degassing, methane production and mineral precipitation. ?? 1978.

  5. Enhancing the natural removal of As in a reactive fluvial confluence receiving acid drainage

    NASA Astrophysics Data System (ADS)

    Abarca, M. I.; Arce, G.; Montecinos, M.; Guerra, P. A.; Pasten, P.

    2014-12-01

    Fluvial confluences are natural reactors that can determine the fate of contaminants in watersheds receiving acid drainage. Hydrological, hydrodynamic and chemical factors determine distinct conditions for the formation of suspended particles of iron and aluminum oxyhydroxides. The chemical and physical properties of these particle assemblages (e.g. particle size, chemical composition) can vary according to inflow mixing ratios, hydrodynamic velocity profiles, and chemical composition of the flows mixing at the confluence. Due to their capacity to sorb metals, it is important to identify the optimal conditions for removing metals from the aqueous phase, particularly arsenic, a contaminant frequently found in acid drainage. We studied a river confluence in the Lluta watershed, located in the arid Chilean Altiplano. We performed field measurements and laboratory studies to find optimal mixing ratio for arsenic sorption onto oxyhydroxide particles at the confluence between the Azufre (pH=2, As=2 mg/L) and the Caracarani river (pH=8, As<0.1 mg/L). As the contribution of the acidic stream increased, the concentration of Fe and Al in the solid phase reached a peak at different pHs. Although the optimal pH for As sorption was ~3, the overall maximum removal of As at the confluence, ocurred for pH~4. This is produced because optimal As sorption does not occur necessarily for the highest concentrations of particles being formed. We propose that fluvial confluences could be engineered to enhance the natural attenuation of contaminants. An analogy between confluences and coagulation-flocculation-sedimentation drinking water plants could be used to engineer such intervention.Acknowledgements: Proyecto Fondecyt 1130936 and Proyecto CONICYT FONDAP 15110020

  6. Chemoenzymatic synthesis of GD3 oligosaccharides and other disialyl glycans containing natural and non-natural sialic acids

    PubMed Central

    Yu, Hai; Cheng, Jiansong; Ding, Li; Khedri, Zahra; Chen, Yi; Chin, Sharlene; Lau, Kam; Tiwari, Vinod Kumar; Chen, Xi

    2009-01-01

    In order to understand the biological importance of naturally occurring sialic acid variations on disialyl structures in nature, we developed an efficient two-step multi-enzyme approach for the synthesis of a series of GD3 ganglioside oligosaccharides and other disialyl glycans containing a terminal Siaα2–8Sia component with different natural and non-natural sialic acids. In the first step, α2–3- or α2–6-linked monosialylated oligosaccharides were obtained using a one-pot three-enzyme approach. These compounds were then used as acceptors for the α2–8-sialyltransferase activity of a recombinant truncated multi-functional Campylobacter jejuni sialyltransferase CstII mutant, CstIIΔ32I53S, to produce disialyl oligosaccharides. The α2–8-sialyltransferase activity of CstIIΔ32I53S has promiscuous donor substrate specificity and can tolerate various substitutions at C-5 or C-9 of the sialic acid in CMP-sialic acid, while its acceptor substrate specificity is relatively restricted. The terminal sialic acid residues in the acceptable monosialylated oligosaccharide acceptors are restricted to Neu5Ac, Neu5Gc, KDN, and some of their C-9 modified forms but not their C-5 derivatives. The disialyl oligosaccharides obtained are valuable probes for their biological studies. PMID:19947630

  7. The SALT NORM : a quantitative chemical-mineralogical characterization of natural waters

    USGS Publications Warehouse

    Bodine, Marc W.; Jones, Blair F.

    1986-01-01

    The new computer program SNORM calculates the salt norm from the chemical composition of a natural water. The salt norm is the quantitative ideal equilibrium assemblage that would crystallize if the water evaporated to dryness at 25 C and 1 bar pressure under atmospheric partial pressure of CO2. SNORM proportions solute concentrations to achieve charge balance. It quantitatively distributes the 18 acceptable solutes into normative salts that are assigned from 63 possible normative salts to allow only stable associations based on the Gibbs Phase Rule, available free energy values, and observed low-temperature mineral associations. Although most natural water compositions represent multiple solute origins, results from SNORM identify three major categories: meteoric or weathering waters that are characterized by normative alkali-bearing sulfate and carbonate salts: connate marine-like waters that are chloride-rich with a halite-bischofite-carnallite-kieserite-anhydrite association; and diagenetic waters that are frequently of marine origin but yield normative salts, such as Ca-bearing chlorides (antarcticite and tachyhydrite) and sylvite, which suggest solute alteration by secondary mineral reactions. The solute source or reaction process within each of the above categories is commonly indicated by the presence or absence of diagnostic normative salts and their relative abundance in the normative salt assemblage. For example, salt norms: (1) may identify lithologic source; (2) may identify the relative roles of carbonic and sulfuric acid hydrolysis in the evolution of weathering waters; (3) may identify the origin of connate water from normal marine, hypersaline, or evaporite salt resolution processes; and (4) may distinguish between dolomitization and silicate hydrolysis or exchange for the origin of diagenetic waters. (Author 's abstract)

  8. Advances in the hydrogeochemistry and microbiology of acid mine waters

    USGS Publications Warehouse

    Nordstrom, D. Kirk

    2000-01-01

    The last decade has witnessed a plethora of research related to the hydrogeochemistry and microbiology of acid mine waters and associated tailings and waste-rock waters. Numerous books, reviews, technical papers, and proceedings have been published that examine the complex bio-geochemical process of sulfide mineral oxidation, develop and apply geochemical models to site characterization, and characterize the microbial ecology of these environments. This review summarizes many of these recent works, and provides references for those investigating this field. Comparisons of measured versus calculated Eh and measured versus calculated pH for water samples from several field sites demonstrate the reliability of some current geochemical models for aqueous speciation and mass balances. Geochemical models are not, however, used to predict accurately time-dependent processes but to improve our understanding of these systems and to constrain possible processes that contribute to actual or potential water quality issues. Microbiological studies are demonstrating that there is much we have yet to learn about the types of different microorganisms and their function and ecology in mine-waste environments. A broad diversity of green algae, bacteria, archaea, yeasts, and fungi are encountered in acid mine waters, and a better understanding of their ecology and function may potentially enhance remediation possibilities as well as our understanding of the evolution of life.

  9. Acidic deposition: State of science and technology. Report 9. Current status of surface-water acid-base chemistry. Final report

    SciTech Connect

    Baker, L.A.; Kaufmann, P.R.; Brakke, D.F.; Herlihy, A.T.; Eilers, J.M.

    1990-09-01

    The report is based largely upon the National Surface Water Survey (NSWS), augmented by numerous smaller state and university surveys and many detailed watershed studies. In describing the current status of surface waters, the authors go far beyond the description of population statistics, although some of this is necessary, and direct their attention to the interpretation of these data. They address the question of the sources of acidity to surface waters in order to determine the relative importance of acidic deposition compared with other sources, such as naturally produced organic acids and acid mine drainage. They also examine in some detail what they call 'high interest' populations-the specific groups of lakes and streams most likely to be impacted by acidic deposition. The authors then turn to the general question of uncertainty, and finally examine low alkalinity surface waters in several other parts of the world to develop further inferences about the acid-base status of surface waters in the United States.

  10. Leveraging abscisic acid receptors for efficient water use in Arabidopsis.

    PubMed

    Yang, Zhenyu; Liu, Jinghui; Tischer, Stefanie V; Christmann, Alexander; Windisch, Wilhelm; Schnyder, Hans; Grill, Erwin

    2016-06-14

    Plant growth requires the influx of atmospheric CO2 through stomatal pores, and this carbon uptake for photosynthesis is inherently associated with a large efflux of water vapor. Under water deficit, plants reduce transpiration and are able to improve carbon for water exchange leading to higher water use efficiency (WUE). Whether increased WUE can be achieved without trade-offs in plant growth is debated. The signals mediating the WUE response under water deficit are not fully elucidated but involve the phytohormone abscisic acid (ABA). ABA is perceived by a family of related receptors known to mediate acclimation responses and to reduce transpiration. We now show that enhanced stimulation of ABA signaling via distinct ABA receptors can result in plants constitutively growing at high WUE in the model species Arabidopsis WUE was assessed by three independent approaches involving gravimetric analyses, (13)C discrimination studies of shoots and derived cellulose fractions, and by gas exchange measurements of whole plants and individual leaves. Plants expressing the ABA receptors RCAR6/PYL12 combined up to 40% increased WUE with high growth rates, i.e., are water productive. Water productivity was associated with maintenance of net carbon assimilation by compensatory increases of leaf CO2 gradients, thereby sustaining biomass acquisition. Leaf surface temperatures and growth potentials of plants growing under well-watered conditions were found to be reliable indicators for water productivity. The study shows that ABA receptors can be explored to generate more plant biomass per water transpired, which is a prime goal for a more sustainable water use in agriculture. PMID:27247417

  11. Leveraging abscisic acid receptors for efficient water use in Arabidopsis

    PubMed Central

    Yang, Zhenyu; Liu, Jinghui; Tischer, Stefanie V.; Christmann, Alexander; Windisch, Wilhelm; Schnyder, Hans; Grill, Erwin

    2016-01-01

    Plant growth requires the influx of atmospheric CO2 through stomatal pores, and this carbon uptake for photosynthesis is inherently associated with a large efflux of water vapor. Under water deficit, plants reduce transpiration and are able to improve carbon for water exchange leading to higher water use efficiency (WUE). Whether increased WUE can be achieved without trade-offs in plant growth is debated. The signals mediating the WUE response under water deficit are not fully elucidated but involve the phytohormone abscisic acid (ABA). ABA is perceived by a family of related receptors known to mediate acclimation responses and to reduce transpiration. We now show that enhanced stimulation of ABA signaling via distinct ABA receptors can result in plants constitutively growing at high WUE in the model species Arabidopsis. WUE was assessed by three independent approaches involving gravimetric analyses, 13C discrimination studies of shoots and derived cellulose fractions, and by gas exchange measurements of whole plants and individual leaves. Plants expressing the ABA receptors RCAR6/PYL12 combined up to 40% increased WUE with high growth rates, i.e., are water productive. Water productivity was associated with maintenance of net carbon assimilation by compensatory increases of leaf CO2 gradients, thereby sustaining biomass acquisition. Leaf surface temperatures and growth potentials of plants growing under well-watered conditions were found to be reliable indicators for water productivity. The study shows that ABA receptors can be explored to generate more plant biomass per water transpired, which is a prime goal for a more sustainable water use in agriculture. PMID:27247417

  12. Fate of the naturally occurring radioactive materials during treatment of acid mine drainage with coal fly ash and aluminium hydroxide.

    PubMed

    Madzivire, Godfrey; Maleka, Peane P; Vadapalli, Viswanath R K; Gitari, Wilson M; Lindsay, Robert; Petrik, Leslie F

    2014-01-15

    Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stations generate huge amounts of coal fly ash of which a small amount is used in the construction industry. Mining exposes pyrite containing rocks to H2O and O2. This results in the oxidation of FeS2 to form H2SO4. The acidic water, often termed acid mine drainage (AMD), causes dissolution of potentially toxic elements such as, Fe, Al, Mn and naturally occurring radioactive materials such as U and Th from the associated bedrock. This results in an outflow of AMD with high concentrations of sulphate ions, Fe, Al, Mn and naturally occurring radioactive materials. Treatment of AMD with coal fly ash has shown that good quality water can be produced which is suitable for irrigation purposes. Most of the potentially toxic elements (Fe, Al, Mn, etc) and substantial amounts of sulphate ions are removed during treatment with coal fly ash. This research endeavours to establish the fate of the radioactive materials in mine water with coal fly ash containing radioactive materials. It was established that coal fly ash treatment method was capable of removing radioactive materials from mine water to within the target water quality range for drinking water standards. The alpha and beta radioactivity of the mine water was reduced by 88% and 75% respectively. The reduced radioactivity in the mine water was due to greater than 90% removal of U and Th radioactive materials from the mine water after treatment with coal fly ash as ThO2 and UO2. No radioisotopes were found to leach from the coal fly ash into the mine water. PMID:24355687

  13. Fate of the naturally occurring radioactive materials during treatment of acid mine drainage with coal fly ash and aluminium hydroxide.

    PubMed

    Madzivire, Godfrey; Maleka, Peane P; Vadapalli, Viswanath R K; Gitari, Wilson M; Lindsay, Robert; Petrik, Leslie F

    2014-01-15

    Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stations generate huge amounts of coal fly ash of which a small amount is used in the construction industry. Mining exposes pyrite containing rocks to H2O and O2. This results in the oxidation of FeS2 to form H2SO4. The acidic water, often termed acid mine drainage (AMD), causes dissolution of potentially toxic elements such as, Fe, Al, Mn and naturally occurring radioactive materials such as U and Th from the associated bedrock. This results in an outflow of AMD with high concentrations of sulphate ions, Fe, Al, Mn and naturally occurring radioactive materials. Treatment of AMD with coal fly ash has shown that good quality water can be produced which is suitable for irrigation purposes. Most of the potentially toxic elements (Fe, Al, Mn, etc) and substantial amounts of sulphate ions are removed during treatment with coal fly ash. This research endeavours to establish the fate of the radioactive materials in mine water with coal fly ash containing radioactive materials. It was established that coal fly ash treatment method was capable of removing radioactive materials from mine water to within the target water quality range for drinking water standards. The alpha and beta radioactivity of the mine water was reduced by 88% and 75% respectively. The reduced radioactivity in the mine water was due to greater than 90% removal of U and Th radioactive materials from the mine water after treatment with coal fly ash as ThO2 and UO2. No radioisotopes were found to leach from the coal fly ash into the mine water.

  14. Study of natural wetlands associated with acid mine drainage. Final research report Jul 87-Dec 90

    SciTech Connect

    Stark, L.R.

    1990-12-01

    Thirty-five natural wetlands impacted by acid mine drainage (mostly in western PA) were surveyed for abiotic and biotic parameters in relation to water quality. Using treatment efficiency and area-adjusted mass retention as wetland performance indices, correlation analyses and multiple regression techniques were employed to evaluate the influence of the wetland parameters on the mitigation of pH, Fe, Mn, and Al. Elevation of pH was correlated with large, broad, low-flow wetlands with shallow, non-channelized surface water, inlet alkalinity, and dense populations of vascular plants and bryophytes. Moderate and high iron concentrations interfered with the mitigation of pH. High Fe treatment efficiencies were correlated to low flows, large areas, broad shapes, non-channelized flows, exposed locations, a diverse and dense vegetative cover, and inlet alkalinity. Large wetlands having lush vascular plant cover and receiving alkaline waters low in total iron concentrations were implicated in significant Mn treatment. Outlet Fe concentrations were usually in compliance in wetlands that significantly lowered Mn concentrations. Algae tolerate manganese but probably do not play an active role in its elimination. Reliable indices of wetland performance include area-adjusted mass retention (for pH) and treatment efficiency (for metals).

  15. Ground-water quality, water year 1995, and statistical analysis of ground-water-quality data, water years 1994-95, at the Chromic Acid Pit site, US Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Roybal, R.G.

    1996-01-01

    The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was closed in 1989, and the Texas Natural Resources Conservation Commission issued permit number HW-50296 (U.S. Environmental Protection Agency number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in monitoring and evaluating ground-water quality at the site. One upgradient ground-water monitoring well (MW1) and two downgradient ground-water monitoring wells (MW2 and MW3), installed adjacent to the chromic acid pit, are monitored on a quarterly basis. Ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The ground-water level, measured in a production well located approximately 1,700 feet southeast of the Chromic Acid Pit site, has declined about 29.43 feet from 1982 to 1995. Depth to water at the Chromic Acid Pit site in September 1995 was 284.2 to 286.5 feet below land surface; ground-water flow at the water table is assumed to be toward the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site during water year 1995 contained dissolved- solids concentrations of 481 to 516 milligrams per liter. Total chromium concentrations detected above the laboratory reporting limit ranged from 0.0061 to 0.030 milligram per liter; dissolved chromium concentrations ranged from 0.0040 to 0.010 milligram per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.8 milligrams per

  16. Natural inactivation of phosphorus by aluminum in atmospherically acidified water bodies.

    PubMed

    Kopácek, J; Ulrich, K U; Hejzlar, J; Borovec, J; Stuchlik, E

    2001-11-01

    Atmospheric acidification of catchment-lake ecosystems may provide natural conditions for the in-lake control of P cycling. This process is based on the elevated transport of aluminum from acidified soils and its subsequent precipitation in the water body and is described for strongly acidified forest lakes, acidified and circumneutral reservoirs, and a moderately acidified alpine lake. In water bodies with episodically or permanently acidified inflows a pH gradient develops between lake water and tributaries due to: (i) neutralization of acidic inflows after mixing with waters with undepleted carbonate buffering system, and/or (ii) the in-lake alkalinity generation dominated by biochemical removal of NO3- and SO4(2-). With the pH increasing towards neutrality, ionic Al species hydrolyze and form colloidal Al hydroxides (Al(part)) with large specific surfaces and strong ability to bind orthophosphate from the liquid phase. Moreover, Alpart settles and increases the P sorption capacity of the sediment. The presence of Al(part) on the bottom reduces orthophosphate release from sediments after its liberation from ferric oxyhydroxides during anoxia because Al(part) is not sensitive to redox changes. Consequently, the natural in-lake P inactivation may be expected in any water body with elevated Al input and a pH gradient between its inlet and outlet.

  17. What is the Imbalance of Water in Nature?

    NASA Astrophysics Data System (ADS)

    Kontar, V. A.

    2011-12-01

    Look at any lake. Water comes into the lake from the atmosphere, from surface and groundwater sources. Water leaves the lake to the atmosphere, surface and underground drains, as well as for consumption by human society, wild plants and animals if they are within the boundaries of the lake's system. If quantity of water coming into the lake is equally of the quantity of water which flow from the lake, so the lake level has not changed and we have a state of equilibration or balance. The bookkeeper's book also has name "balance". But this is just a play on words. If the water is coming into the lake more than the water is coming away from lake, therefore the lake level will increase and we have a state of the imbalance of the increase type. If the water is coming into the lake less than the water is coming away from lake, therefore the lake level will decrease and we have a state of the imbalance of the decrease type. Everyone knows that the lake level rises or falls, for example during the year. Sometimes it is happened some balance. But the state of balance is rare and in of the short duration. The lake is of most the time in the conditions of the imbalance increases or the imbalance decreases type. The balance as a state of equilibrium, in the language of mathematics, is the point of the extremum between the periods of rise and fall. The balance is a special condition, which is existing very rare and a very short period of time. The people sometimes to do the great efforts for maintain the constant level of the lakes. But these facts don't change the situation. On the contrary, the human's struggle for maintain the lake in constant level just shows how difficult and expensive to go against the natural laws of Nature. When water was plentiful, these facts could be ignored. But now when the global water shortage is quickly growing, many previously ignored details are becoming crucial. There are very important to do the correct definitions of the borders and

  18. Reduction of Fe(III) with sulfite in natural waters

    NASA Astrophysics Data System (ADS)

    Millero, F. J.; Gonzalez-Davila, M.; Santana-Casiano, J. M.

    1995-04-01

    The Fe(III) in marine aerosols and rainwaters can be reduced to Fe(II) by photochemical processes and by reactions with sulfite. In this paper, measurements of the rates of reduction of nanomolar levels of Fe(III) with sulfite (without O2) have been determined in NaCl and seawater solutions as a function of temperature (0° to 40°C), pH (2 to 6.8), ionic strength (I = 0.1 to 6 M), and composition (Na+, Mg2+, Ca2+, F-, Cl-, Br-, HCO3-, SO42-). The overall rate constant (k, M-1 min-1) for the reaction, Fe>(III>)+S>(IV>)>→k products, is given by d[Fe(III)]/dt = -k[Fe(III)] [S(IV)]. The reaction was found to be first order with respect to Fe(III) and S(IV). The rate constants as a function of pH increased from a pH = 2 to 4 and decreased at higher pH. The effect of temperature and ionic strength on the rates could be represented by log k = log k0 + AI0.5/(1 + I0.5), where A = -1.1 in NaCl and -2.2 in seawater and log k0 = 25.39 - 6,323/T. The energy of activation was found by 121±6 kJ mol-1. The measured rates in seawater as a function of salinity were lower than the rates in NaCl at the same ionic strength. Measurements in NaCl solutions with added sea-salt ions (Mg2+, Ca2+, F-, Br-, and SO42-) at pH = 3.5 indicate that the formation of inert FeF2+ may be responsible for the lower rates. The effect of changes in the composition on the rates was interpreted by examining the speciation of Fe(III) and S(IV). This analysis indicates that the rate-determining steps from a pH of 2.5 to 4.0 are FeOH2+ + HSO3- ↔ HOFeSO3H + and HOFeSO3H+>⟶k1FeOH++HSO3· and at pH of 4 to 6, the reactions Fe(OH)2+ + HSO3- ↔ (HO)2FeSO3H and >(HO>)2FeSO3H>⟶k2Fe>(OH>)2+HSO3· become important. The changes in the concentration of FeOH2+ and HSO3- as a function of pH and composition can account for most of the changes in the rates. These kinetic studies indicate that the rates of reduction of Fe(III) with S(IV) in acidic water droplets at natural levels of S(IV) may be an important

  19. Using naturally occurring radionuclides to determine drinking water age in a community water system

    SciTech Connect

    Waples, James T.; Bordewyk, Jason K.; Knesting, Kristina M.; Orlandini, Kent A.

    2015-07-22

    Drinking water quality in a community water system is closely linked to the age of water from initial treatment to time of delivery. However, water age is difficult to measure with conventional chemical tracers; particularly in stagnant water, where the relationship between disinfectant decay, microbial growth, and water age is poorly understood. Using radionuclides that were naturally present in source water, we found that measured activity ratios of 90Y/90Sr and 234Th/238U in discrete drinking water samples of known age accurately estimated water age up to 9 days old (σest: ± 3.8 h, P < 0.0001, r2 = 0.998, n = 11) and 25 days old (σest: ± 13.3 h, P < 0.0001, r2 = 0.996, n = 12), respectively. Moreover, 90Y-derived water ages in a community water system (6.8 × 104 m3 d–1 capacity) were generally consistent with water ages derived from an extended period simulation model. Radionuclides differ from conventional chemical tracers in that they are ubiquitous in distribution mains and connected premise plumbing. The ability to measure both water age and an analyte (e.g., chemical or microbe) in any water sample at any time allows for new insight into factors that control drinking water quality.

  20. Evaluation of acute copper toxicity to juvenile freshwater mussels (fatmucket, lampsilis siliquoidea) in natural and reconstituted waters

    USGS Publications Warehouse

    Wang, N.; Mebane, C.A.; Kunz, J.L.; Ingersoll, C.G.; May, T.W.; Arnold, W.R.; Santore, R.C.; Augspurger, T.; Dwyer, F.J.; Barniiart, M.C.

    2009-01-01

    The influence of dissolved organic carbon (DOC) and water composition on the toxicity of copper to juvenile freshwater mussels (fatmucket, Lampsilis siliquoidea) were evaluated in natural and reconstituted waters. Acute 96-h copper toxicity tests were conducted at four nominal DOC concentrations (0, 2.5, 5, and 10 mg/L as carbon [C]) in dilutions of natural waters and in American Society for Testing and Materials (ASTM) reconstituted hard water. Toxicity tests also were conducted in ASTM soft, moderately hard, hard, and very hard reconstituted waters (nominal hardness 45-300 mg/L as CaCO3). Three natural surface waters (9.5-11 mg/L DOC) were diluted to obtain a series of DOC concentrations with diluted well water, and an extract of natural organic matter and commercial humic acid was mixed with ASTM hard water to prepare a series of DOC concentrations for toxicity testing. Median effective concentrations (EC50s) for dissolved copper varied >40-fold (9.9 to >396 ??g Cu/L) over all 21 treatments in various DOC waters. Within a particular type of DOC water, EC50s increased 5- to 12-fold across DOC concentrations of 0.3 to up to 11 mg C/L. However, EC50s increased by only a factor of 1.4 (21 30 ??g Cu/L) in the four ASTM waters with wide range of water hardness (52-300 mg CaCO 3/L). Predictions from the biotic ligand model (BLM) for copper explained nearly 90% of the variability in EC50s. Nearly 70% of BLM-normalized EC50s for fatmucket tested in natural waters were below the final acute value used to derive the U.S. Environmental Protection Agency acute water quality criterion for copper, indicating that the criterion might not be protective of fatmucket and perhaps other mussel species. ?? 2009 SETAC.

  1. Phenomenon of organic carbon change in natural waters (system "catchment - Lake") of Russian Federation

    NASA Astrophysics Data System (ADS)

    Dinu, Marina; Tatyana, Moiseenko; Tatyana, Kremleva; Natalia, Gashkina

    2015-04-01

    In the last two decades in the Russian Federation was found significant increase in the concentration of dissolved organic carbon in many aqueous systems. Most obviously, these changes may be related to global warming. It is known that increasing the temperature dominate during dry periods and increases the concentration of nutrients, primary production increases, leading to an increase of the dissolved organic matter. At the same time, it is known that some of the increase in DOC may be largely due to a decrease of anthropogenic sulfur deposition and increasing organic matter in the soil. The European Russia (ER) is a region with substantial industrial emissions of sulphur. In the central part of ER are concentrated metallurgical productions. This has resulted in high concentrations of anthropogenic sulphate and an increase in the prevalence of acidification as well as a rise in metal concentrations in the lakes of North Kola. However, over the last 30 years, sulfur emissions in ?ola North have decreased substantially. The aim of this work was to explain the mechanisms to improve the content of natural organic matter and to assess its role in the processes of acidification and recovery of water quality while reducing the deposition of technogenic acid. The increasing of organic matter content in lake waters is being also observed for the totality of lakes in the Kola North. This conforms to the data reported by Skjelkvale et al. (2001a) which demonstrates the significant increase of DOC. Some authors explain the increased DOC levels by reduction in strong acid flow and return of water chemistry to its natural parameters of specifying organic matter concentrations in water. It is known that DOC level has a direct relationship with water color. In analyzing long-term study data with regard to the group of 75 lakes (obtained during 1990-2010) DOC is increased year-over-year, but the color decreased. The following chemical processes developing in water can explain

  2. Palmitoleic acid calcium salt: a lubricant and bactericidal powder from natural lipids.

    PubMed

    Yamamoto, Yoshiaki; Kawamura, Yuki; Yamazaki, Yuki; Kijima, Tatsuro; Morikawa, Toshiya; Nonomura, Yoshimune

    2015-01-01

    Palmitoleic acid is a promising bactericidal agent for cleansing products with alternative bactericidal abilities. In this study, we focus on the physical and biological activity of palmitoleic acid calcium salt (C16:1 fatty acid Ca salt) because it forms via an ion-exchange reaction between palmitoleic acid and Ca ions in tap water, and remains on the skin surface during the cleansing process. Here, we prepared C16:1 fatty acid Ca salt to investigate its crystal structure and physical and bactericidal properties. The Ca salt was a plate-shaped lamellar crystalline powder with a particle diameter of several micrometers to several tens of micrometers; it exhibited significant lubricity and alternative bactericidal activity against Staphylococcus aureus (S. aureus) and Propionibacterium acnes (P. acnes). We also examined other fatty acid Ca salts prepared from lauric acid (C12:0 fatty acid), palmitic acid (C16:0 fatty acid), and oleic acid (C18:1 fatty acid). The bactericidal activities and lubricity of the fatty acid Ca salts changed with the alkyl chain length and the degree of unsaturation. The C16:1 fatty acid Ca salt exhibited the strongest selective bactericidal ability among the four investigated fatty acid Ca salts. These findings suggest that C16:1 fatty acid and its Ca salt have potential applications in cleansing and cosmetic products. PMID:25757432

  3. Isotopic analysis of uranium in natural waters by alpha spectrometry

    USGS Publications Warehouse

    Edwards, K.W.

    1968-01-01

    A method is described for the determination of U234/U238 activity ratios for uranium present in natural waters. The uranium is coprecipitated from solution with aluminum phosphate, extracted into ethyl acetate, further purified by ion exchange, and finally electroplated on a titanium disc for counting. The individual isotopes are determined by measurement of the alpha-particle energy spectrum using a high resolution low-background alpha spectrometer. Overall chemical recovery of about 90 percent and a counting efficiency of 25 percent allow analyses of water samples containing as little as 0.10 ?g/l of uranium. The accuracy of the method is limited, on most samples, primarily by counting statistics.

  4. Polycyclic aromatic hydrocarbon removal from water by natural fiber sorption.

    PubMed

    Khan, Eakalak; Khaodhir, Sutha; Rotwiron, Paritta

    2007-08-01

    The use of two natural sorbents, kapok and cattail fibers, were investigated for polycyclic aromatic hydrocarbon (PAH) removal from water. Naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, and fluoranthene were the PAHs studied. For comparative purposes, a commercial polyester fiber sorbent was included in the investigation. The PAH sorption and retention capabilities of the three fibers were determined through batch and continuous-flow experiments under non-competitive and competitive conditions. In the batch experiments, cattail fiber was the most effective sorbent. Kapok fiber provided the lowest PAH retention, while cattail fiber had slightly less PAH retention than polyester fiber. When two PAHs were present in the same system, a competitive effect on the much less hydrophobic PAH was observed. Similar results were obtained in the column experiments, except that polyester fiber performed much poorer on naphthalene. Cattail fiber is a promising sorbent for treating PAH-contaminated water, such as urban runoff.

  5. Water: Challenges at the Intersection of Human and Natural Systems

    SciTech Connect

    Futrell, J.H.; Gephart, R. E.; Kabat-Lensch, E.; McKnight, D. M.; Pyrtle, A.; Schimel, J. P.; Smyth, R. L.; Skole, D. L. Wilson, J. L.; Gephart, J. M.

    2005-09-01

    There is a growing recognition about the critical role water plays in sustaining people and society. This workshop established dialog between disciplinary scientists and program managers from diverse backgrounds in order to share perspectives and broaden community understanding of ongoing fundamental and applied research on water as a complex environmental problem. Three major scientific themes emerged: (1) coupling of cycles and process, with emphasis on the role of interfaces; (2) coupling of human and natural systems across spatial and temporal scales; and (3) prediction in the face of uncertainty. In addition, the need for observation systems, sensors, and infrastructure; and the need for data management and synthesis were addressed. Current barriers to progress were noted as educational and institutional barriers and the integration of science and policy.

  6. Measurement of "turbidity" and related characteristics of natural waters

    USGS Publications Warehouse

    Pickering, R.J.

    1976-01-01

    The U.S. Geological Survey, Water Resources Division has adopted the following principles to be used in selecting methods for the measurement of light transmitting characteristics of natural waters: (1) standard instruments and methods are to be adopted to measure and report in optical units, avoiding ' turbidity ' as a quantitative measure; (2) reporting of ' turbidity ' in JTU 's, Hellige units, severity, or NTU 's will be phased out; (3) the basis for estimations of sediment concentrations based on light measurements must be documented adequately; and (4) use of transparency measurement by Secchi disk is not changed, although light transmittance may prove to be more precise means of obtaining the same information. A schedule has been established to implement new methods beginning October 1, 1976, and with the transition to be completed at all stations by October 1, 1977. Provisions are provided to meet requirements of cooperators who have legal requirements for ' turbidity ' data. (Woodard-USGS)

  7. Removal of coagulant aluminum from water treatment residuals by acid.

    PubMed

    Okuda, Tetsuji; Nishijima, Wataru; Sugimoto, Mayo; Saka, Naoyuki; Nakai, Satoshi; Tanabe, Kazuyasu; Ito, Junki; Takenaka, Kenji; Okada, Mitsumasa

    2014-09-01

    Sediment sludge during coagulation and sedimentation in drinking water treatment is called "water treatment residuals (WTR)". Polyaluminum chloride (PAC) is mainly used as a coagulant in Japan. The recycling of WTR has been desired; one method for its reuse is as plowed soil. However, WTR reuse in this way is inhibited by the aluminum from the added PAC, because of its high adsorption capacity for phosphate and other fertilizer components. The removal of such aluminum from WTR would therefore be advantageous for its reuse as plowed soil; this research clarified the effect of acid washing on aluminum removal from WTR and on plant growth in the treated soil. The percentage of aluminum removal from raw WTR by sulphuric acid solution was around 90% at pH 3, the percentage decreasing to 40% in the case of a sun-dried sample. The maximum phosphate adsorption capacity was decreased and the available phosphorus was increased by acid washing, with 90% of aluminum removal. The enhancement of Japanese mustard spinach growth and the increased in plant uptake of phosphates following acid washing were observed.

  8. Ice-like encapsulated water by two cholic acid moieties.

    PubMed

    Soto, Victor H; Alvarez, Mercedes; Meijide, Francisco; Trillo, Juan V; Antelo, Alvaro; Jover, Aida; Galantini, L; Tato, José Vázquez

    2012-10-01

    Starting from the structure of ice (in which each water molecule is surrounded by other four water molecules forming a tetrahedron with a value of 4.51Å for the edge O-O distance), and the knowledge that this value also corresponds to the O7-O12 distance of the skeleton of cholic acid, it is hypothesized that two steroid cholic acid moieties, with an appropriate steroid-steroid distance and a belly-to-belly orientation, could encapsulate a single water molecule between them. To check this hypothesis two succinyl derivatives of cholic acid (a monomer and the related head-head dimer in which the succinyl group is the linking bridge) were designed. The expected "ice-like" structure is found in the crystal of the dimer. There is a hydrogen bond synergy between those participating in the "ice-like" structure, and those in which the bridge is involved with the O7-H hydroxy group and the side chain of the steroid.

  9. Natural vs. random protein sequences: Discovering combinatorics properties on amino acid words.

    PubMed

    Santoni, Daniele; Felici, Giovanni; Vergni, Davide

    2016-02-21

    Casual mutations and natural selection have driven the evolution of protein amino acid sequences that we observe at present in nature. The question about which is the dominant force of proteins evolution is still lacking of an unambiguous answer. Casual mutations tend to randomize protein sequences while, in order to have the correct functionality, one expects that selection mechanisms impose rigid constraints on amino acid sequences. Moreover, one also has to consider that the space of all possible amino acid sequences is so astonishingly large that it could be reasonable to have a well tuned amino acid sequence indistinguishable from a random one. In order to study the possibility to discriminate between random and natural amino acid sequences, we introduce different measures of association between pairs of amino acids in a sequence, and apply them to a dataset of 1047 natural protein sequences and 10,470 random sequences, carefully generated in order to preserve the relative length and amino acid distribution of the natural proteins. We analyze the multidimensional measures with machine learning techniques and show that, to a reasonable extent, natural protein sequences can be differentiated from random ones.

  10. Natural vs. random protein sequences: Discovering combinatorics properties on amino acid words.

    PubMed

    Santoni, Daniele; Felici, Giovanni; Vergni, Davide

    2016-02-21

    Casual mutations and natural selection have driven the evolution of protein amino acid sequences that we observe at present in nature. The question about which is the dominant force of proteins evolution is still lacking of an unambiguous answer. Casual mutations tend to randomize protein sequences while, in order to have the correct functionality, one expects that selection mechanisms impose rigid constraints on amino acid sequences. Moreover, one also has to consider that the space of all possible amino acid sequences is so astonishingly large that it could be reasonable to have a well tuned amino acid sequence indistinguishable from a random one. In order to study the possibility to discriminate between random and natural amino acid sequences, we introduce different measures of association between pairs of amino acids in a sequence, and apply them to a dataset of 1047 natural protein sequences and 10,470 random sequences, carefully generated in order to preserve the relative length and amino acid distribution of the natural proteins. We analyze the multidimensional measures with machine learning techniques and show that, to a reasonable extent, natural protein sequences can be differentiated from random ones. PMID:26656109

  11. In situ measurement of inelastic light scattering in natural waters

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin

    Variation in the shape of solar absorption (Fraunhofer) lines are used to study the inelastic scattering in natural waters. In addition, oxygen absorption lines near 689nm are used to study the solar stimulated chlorophyll fluorescence. The prototype Oceanic Fraunhofer Line Discriminator (OFLD) has been further developed and improved by using a well protected fiber optic - wire conductor cable and underwater electronic housing. A Monte-Carlo code and a simple code have been modified to simulate the Raman scattering, DOM fluorescence and chlorophyll fluorescence. A series of in situ measurements have been conducted in clear ocean waters in the Florida Straits, in the turbid waters of Florida Bay, and in the vicinity of a coral reef in the Dry Tortugas. By comparing the reduced data with the model simulation results, the Raman scattering coefficient, b r with an excitation wavelength at 488nm, has been verified to be 2.6 × 10-4m-1 (Marshall and Smith, 1990), as opposed to 14.4 × 10- 4m-1 (Slusher and Derr, 1975). The wavelength dependence of b r cannot be accurately determined from the data set as the reported values (λ m-4 to λ m- 5) have an insignificant effect in the natural underwater light field. Generally, in clear water, the percentage of inelastic scattered light in the total light field at /lambda < 510nm is negligible for the whole water column, and this percentage increases with depth at /lambda > 510nm. At low concentrations (a y(/lambda = 380nm) less than 0.1m-1), DOM fluorescence plays a small role in the inelastic light field. However, chlorophyll fluorescence is much stronger than Raman scattering at 685nm. In shallow waters where a sea bottom affects the ambient light field, inelastic light is negligible for the whole visible band. Since Raman scattering is now well characterized, the new OFLD can be used to measure the solar stimulated in situ fluorescence. As a result, the fluorescence signals of various bottom surfaces, from coral to

  12. Water adsorption around oxalic acid aggregates: a molecular dynamics simulation of water nucleation on organic aerosols.

    PubMed

    Darvas, Maria; Picaud, Sylvain; Jedlovszky, Pál

    2011-11-28

    The phase behaviour of binary oxalic acid-water mixtures has been investigated by means of computer simulation techniques. Such mixtures play an important role in atmospheric processes, since the hydrogen bonding ability of oxalic acid molecules allows them to form aerosol particles. Water can in turn be readily adsorbed on the surface of such aerosol particles, which results in the formation of small ice grains. These grains are thus considered to be acting as cloud condensation nuclei, giving rise to the formation of ice clouds.

  13. 75 FR 9921 - San Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... Fish and Wildlife Service San Diego County Water Authority Natural Communities Conservation Program/Habitat Conservation Plan, San Diego and Riverside Counties, CA AGENCY: Fish and Wildlife Service... the Draft Water Authority Natural Communities Conservation Program/Habitat Conservation Plan...

  14. An outbreak of oropharyngeal tularaemia linked to natural spring water.

    PubMed

    Willke, A; Meric, M; Grunow, R; Sayan, M; Finke, E J; Splettstösser, W; Seibold, E; Erdogan, S; Ergonul, O; Yumuk, Z; Gedikoglu, S

    2009-01-01

    A tularaemia outbreak was investigated involving 188 suspected cases in the Kocaeli region of Turkey between December 2004 and April 2005. A case-control study comprising 135 laboratory-confirmed cases and 55 controls was undertaken to identify risk factors for the development of the outbreak and to evaluate laboratory diagnostic methods. Tularaemia was confirmed by a microagglutination test (MAT) titre of >or=1 : 160 in 90 of the patients. In MAT-negative sera, 23/44 (52 %) were positive by ELISA with Francisella tularensis LPS and 1/9 (11 %) by Western blotting with this antigen. A species-specific PCR was positive in 16/25 (64 %) throat swabs and 8/13 (62 %) lymph node aspirates. Multivariate analysis showed that drinking natural spring water was the leading risk factor for the development of tularaemia (P=0.0001, odds ratio 0.165, 95 % CI 0.790-0.346). The outbreak ceased after abandonment of the suspected natural water springs.

  15. Use of natural and applied tracers to guide targeted remediation efforts in an acid mine drainage system, Colorado Rockies, USA

    USGS Publications Warehouse

    Cowie, Rory; Williams, Mark W.; Wireman, Mike; Runkel, Robert L.

    2014-01-01

    Stream water quality in areas of the western United States continues to be degraded by acid mine drainage (AMD), a legacy of hard-rock mining. The Rico-Argentine Mine in southwestern Colorado consists of complex multiple-level mine workings connected to a drainage tunnel discharging AMD to passive treatment ponds that discharge to the Dolores River. The mine workings are excavated into the hillslope on either side of a tributary stream with workings passing directly under the stream channel. There is a need to define hydrologic connections between surface water, groundwater, and mine workings to understand the source of both water and contaminants in the drainage tunnel discharge. Source identification will allow targeted remediation strategies to be developed. To identify hydrologic connections we employed a combination of natural and applied tracers including isotopes, ionic tracers, and fluorescent dyes. Stable water isotopes (δ18O/δD) show a well-mixed hydrological system, while tritium levels in mine waters indicate a fast flow-through system with mean residence times of years not decades or longer. Addition of multiple independent tracers indicated that water is traveling through mine workings with minimal obstructions. The results from a simultaneous salt and dye tracer application demonstrated that both tracer types can be successfully used in acidic mine water conditions.

  16. Faecal bile acids are natural ligands of the mouse accessory olfactory system.

    PubMed

    Doyle, Wayne I; Dinser, Jordan A; Cansler, Hillary L; Zhang, Xingjian; Dinh, Daniel D; Browder, Natasha S; Riddington, Ian M; Meeks, Julian P

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  17. Faecal bile acids are natural ligands of the mouse accessory olfactory system

    PubMed Central

    Doyle, Wayne I.; Dinser, Jordan A.; Cansler, Hillary L.; Zhang, Xingjian; Dinh, Daniel D.; Browder, Natasha S.; Riddington, Ian M.; Meeks, Julian P.

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  18. Water quality of hydrologic bench marks; an indicator of water quality in the natural environment

    USGS Publications Warehouse

    Biesecker, James E.; Leifeste, Donald K.

    1974-01-01

    Water-quality data, collected at 57 hydrologic bench-mark stations in 37 States, allow the definition of water quality in the 'natural' environment and the comparison of 'natural' water quality with water quality of major streams draining similar water-resources regions. Results indicate that water quality in the 'natural' environment is generally very good. Streams draining hydrologic bench-mark basins generally contain low concentrations of dissolved constituents. Water collected at the hydrologic bench-mark stations was analyzed for the following minor metals: arsenic, barium, cadmium, hexavalent chromium, cobalt, copper, lead, mercury, selenium, silver, and zinc. Of 642 analyses, about 65 percent of the observed concentrations were zero. Only three samples contained metals in excess of U.S. Public Health Service recommended drinking-water standards--two selenium concentrations and one cadmium concentration. A total of 213 samples were analyzed for 11 pesticidal compounds. Widespread but very low-level occurrence of pesticide residues in the 'natural' environment was found--about 30 percent of all samples contained low-level concentrations of pesticidal compounds. The DDT family of pesticides occurred most commonly, accounting for 75 percent of the detected occurrences. The highest observed concentration of DDT was 0.06 microgram per litre, well below the recommended maximum permissible in drinking water. Nitrate concentrations in the 'natural' environment generally varied from 0.2 to 0.5 milligram per litre. The average concentration of nitrate in many major streams is as much as 10 times greater. The relationship between dissolved-solids concentration and discharge per unit area in the 'natural' environment for the various physical divisions in the United States has been shown to be an applicable tool for approximating 'natural' water quality. The relationship between dissolved-solids concentration and discharge per unit area is applicable in all the physical

  19. Photochemistry of excited-state species in natural waters: a role for particulate organic matter.

    PubMed

    Cottrell, Barbara A; Timko, Stephen A; Devera, Lianne; Robinson, Alice K; Gonsior, Michael; Vizenor, Ashley E; Simpson, André J; Cooper, William J

    2013-09-15

    Laser flash photolysis (LFP) was used to characterize a triplet excited state species isolated from Black River and San Joaquin wetlands particulate organic matter (POM). The solubilized organic matter, isolated from POM by pH-independent diffusion in distilled water, was named PdOM. UV-visible absorption spectroscopy, excitation-emission matrix spectroscopy (EEMs), and (1)H NMR were used to characterize the PdOM. While LFP of dissolved organic matter (DOM) is known to generate the solvated electron, LFP of the PdOM transient in argon-, air-, and nitrous oxide-saturated solutions indicated that this was a triplet excited state species ((3)PdOM*). The lifetime and the reactivity of (3)PdOM* with sorbic acid, a triplet state quencher, were compared with that of the triplet excited state of benzophenone, a DOM proxy. A second excited state species (designated DOM*), with a longer lifetime, was reported in a number of previous studies but not characterized. The lifetime of DOM*, measured for seventeen organic matter isolates, lignin, tannic acid, and three wetlands plant extracts, was shown to differentiate allochthonous from autochthonous DOM. (3)POM* and DOM* were also observed in lake water and a constructed wetlands' water. Aqueous extracts of fresh and aged plant material from the same wetland were shown to be one source of these excited state species. This study provides evidence of a role for POM in the photochemistry of natural and constructed wetland waters.

  20. Student Knowledge of Scientific and Natural Resource Concepts Concerning Acidic Deposition.

    ERIC Educational Resources Information Center

    Brody, Michael; And Others

    1989-01-01

    Assessed is the level of scientific and natural resource knowledge possessed by fourth-, eighth- and eleventh-grade students. Misconceptions are noted. Discussed are implications for teaching about acidic deposition. (CW)

  1. Ascorbic Acid Determination in Natural Orange Juice: As a Teaching Tool of Coulometry and Polarography.

    ERIC Educational Resources Information Center

    Bertotti, Mauro; And Others

    1995-01-01

    Describes an experiment designed to determine ascorbic acid concentrations in natural orange juice. The experiment is used with undergraduate pharmacy students to allow understanding of the principles of operation of the coulometer and polarograph. (DDR)

  2. Cyclic Sulfamidate Enabled Syntheses of Amino Acids, Peptides, Carbohydrates, and Natural Products

    EPA Science Inventory

    This article reviews the emergence of cyclic sulfamidates as versatile intermediatesfor the synthesis of unnatural amino acids, chalcogen peptides, modified sugars, drugs and drug candidates, and important natural products.

  3. Total Synthesis and Biological Evaluation of the Tetramic Acid Based Natural Product Harzianic Acid and Its Stereoisomers

    PubMed Central

    2015-01-01

    The bioactive natural product harzianic acid was prepared for the first time in just six steps (longest linear sequence) with an overall yield of 22%. The identification of conditions to telescope amide bond formation and a Lacey–Dieckmann reaction into one pot proved important. The three stereoisomers of harzianic acid were also prepared, providing material for comparison of their biological activity. While all of the isomers promoted root growth, improved antifungal activity was unexpectedly associated with isomers in the enantiomeric series opposite that of harzianic acid. PMID:25629709

  4. Microwave-enhanced pyrolysis of natural algae from water blooms.

    PubMed

    Zhang, Rui; Li, Linling; Tong, Dongmei; Hu, Changwei

    2016-07-01

    Microwave-enhanced pyrolysis (MEP) of natural algae under different reaction conditions was carried out. The optimal conditions for bio-oil production were the following: algae particle size of 20-5 mesh, microwave power of 600W, and 10% of activated carbon as microwave absorber and catalyst. The maximum liquid yield obtained under N2, 10% H2/Ar, and CO2 atmosphere was 49.1%, 51.7%, and 54.3% respectively. The energy yield of bio-products was 216.7%, 236.9% and 208.7% respectively. More long chain fatty acids were converted into hydrocarbons by hydrodeoxygenation under 10% H2/Ar atmosphere assisted by microwave over activated carbon containing small amounts of metals. Under CO2 atmosphere, carboxylic acids (66.6%) were the main products in bio-oil because the existence of CO2 vastly inhibited the decarboxylation. The MEP of algae was quick and efficient for bio-oil production, which provided a way to not only ameliorate the environment but also obtain fuel or chemicals at the same time.

  5. Microwave-enhanced pyrolysis of natural algae from water blooms.

    PubMed

    Zhang, Rui; Li, Linling; Tong, Dongmei; Hu, Changwei

    2016-07-01

    Microwave-enhanced pyrolysis (MEP) of natural algae under different reaction conditions was carried out. The optimal conditions for bio-oil production were the following: algae particle size of 20-5 mesh, microwave power of 600W, and 10% of activated carbon as microwave absorber and catalyst. The maximum liquid yield obtained under N2, 10% H2/Ar, and CO2 atmosphere was 49.1%, 51.7%, and 54.3% respectively. The energy yield of bio-products was 216.7%, 236.9% and 208.7% respectively. More long chain fatty acids were converted into hydrocarbons by hydrodeoxygenation under 10% H2/Ar atmosphere assisted by microwave over activated carbon containing small amounts of metals. Under CO2 atmosphere, carboxylic acids (66.6%) were the main products in bio-oil because the existence of CO2 vastly inhibited the decarboxylation. The MEP of algae was quick and efficient for bio-oil production, which provided a way to not only ameliorate the environment but also obtain fuel or chemicals at the same time. PMID:27128164

  6. Phosphatidic acid, a versatile water-stress signal in roots

    PubMed Central

    McLoughlin, Fionn; Testerink, Christa

    2013-01-01

    Adequate water supply is of utmost importance for growth and reproduction of plants. In order to cope with water deprivation, plants have to adapt their development and metabolism to ensure survival. To maximize water use efficiency, plants use a large array of signaling mediators such as hormones, protein kinases, and phosphatases, Ca2+, reactive oxygen species, and low abundant phospholipids that together form complex signaling cascades. Phosphatidic acid (PA) is a signaling lipid that rapidly accumulates in response to a wide array of abiotic stress stimuli. PA formation provides the cell with spatial and transient information about the external environment by acting as a protein-docking site in cellular membranes. PA reportedly binds to a number of proteins that play a role during water limiting conditions, such as drought and salinity and has been shown to play an important role in maintaining root system architecture. Members of two osmotic stress-activated protein kinase families, sucrose non-fermenting 1-related protein kinase 2 and mitogen activated protein kinases were recently shown bind PA and are also involved in the maintenance of root system architecture and salinity stress tolerance. In addition, PA regulates several proteins involved in abscisic acid-signaling. PA-dependent recruitment of glyceraldehyde-3-phosphate dehydrogenase under water limiting conditions indicates a role in regulating metabolic processes. Finally, a recent study also shows the PA recruits the clathrin heavy chain and a potassium channel subunit, hinting toward additional roles in cellular trafficking and potassium homeostasis. Taken together, the rapidly increasing number of proteins reported to interact with PA implies a broad role for this versatile signaling phospholipid in mediating salt and water stress responses. PMID:24391659

  7. Phase and extraction equilibria in water-polyethyleneglycol ethers of monoethanolamides of synthetic fatty acid-ammonium chloride systems

    NASA Astrophysics Data System (ADS)

    Lesnov, A. E.; Golovkina, A. V.; Kudryashova, O. S.; Denisova, S. A.

    2016-08-01

    Phase equilibria in layering systems of water, polyethyleneglycol ethers of monoethanolamides of synthetic fatty acids (SFAs) (synthamide-5), and ammonium chloride are studied. The possibility of using such systems for the liquid extraction of metal ions is evaluated. The effect the nature of salting-out agents has on the processes of segregation of the systems has been considered.

  8. Water Reserves Program. An adaptation strategy to prevent imbalance of water in nature

    NASA Astrophysics Data System (ADS)

    Salinas-Rodriguez, S. A.; López Pérez, M.; Barrios Ordóñez, J.; Wickel, B.; Villón Bracamonte, R. A.

    2013-12-01

    Freshwater ecosystems occupy approximately 1% of the earth's surface yet possess about 12% of all known animal species. By virtue of their position in the landscape they connect terrestrial and coastal marine biomes and provide and sustain ecosystem services vital to the health and persistence of human communities. These services include the supply of water for food production, urban and industrial consumption, among others. Over the past century many freshwater ecosystems around the world have been heavily modified or lost due to the alteration of flow regimes (e.g. damming, canalization, diversion, over-abstraction). The synergistic impacts of land use change, changes in flows, chemical deterioration, and climate change have left many systems and their species very little room to adjust to change, while future projections indicate a steady increase imbalance in water demand for food and energy production and water supply to suit the needs of a growing world population. In Mexico, the focus has been to secure water for human development and maximize economic growth, which has resulted in allocation of water beyond available amounts, and that in many river basins has led imbalance of water in nature. As a consequence episodic water scarcity severely constrains freshwater ecosystems and the services they provide. Climatic change and variability are presenting serious challenges to a country that already is experiencing serious strain on its water resources. However, freshwater ecosystems are recognized by law as legitimate user of water, and mandate a flow allocation for the environment ('water reserve' or 'environmental flows'). Based on this legal provision the Mexican government through the National Water Commission (Conagua), with support of the Alliance WWF - Fundación Gonzalo Río Arronte, and the Interamerican Development Bank, has launched a national program to identify and implement 'water reserves': basins where environmental flows will be secured and

  9. Chiroptical spectroscopy of natural products: avoiding the aggregation effects of chiral carboxylic acids.

    PubMed

    Polavarapu, Prasad L; Donahue, Emily A; Hammer, Karissa C; Raghavan, Vijay; Shanmugam, Ganesh; Ibnusaud, Ibrahim; Nair, Divya S; Gopinath, Chithra; Habel, Deenamma

    2012-08-24

    Determination of the absolute configurations and predominant conformations of chiral natural products, occurring as carboxylic acids, using chiroptical spectroscopic methods becomes challenging due to the formation of solute aggregates (in the form of dimers, etc.) and/or solute-solvent complexes resulting from intermolecular hydrogen bonding with solvent. A hypothesis that such aggregation effects can be avoided by using corresponding sodium salts or acid anhydrides for chiroptical spectroscopic measurements has been tested. For this purpose, vibrational circular dichroism, electronic circular dichroism, and optical rotatory dispersion spectra for disodium salts of two natural products, hibiscus acid and garcinia acid, and the anhydride of acetylated garcinia acid have been measured. These experimental spectra are analyzed in combination with quantum chemical calculations of corresponding spectra. The spectral analysis for sodium salts and anhydride turned out to be simpler, suggesting that the conversion of carboxylic acids to corresponding salts or anhydride can be advantageous for the application of chiroptical spectroscopy. PMID:22877358

  10. Radiological of natural and mineral drinking waters in Slovenia.

    PubMed

    Benedik, L; Jeran, Z

    2012-08-01

    Various types of water were collected in Slovenia and analysed in order to assess the radiation doses from (238)U, (234)U, (228)Ra, (226)Ra, (210)Pb and (210)Po for three different age groups of the population. It was found in all cases that the calculated median committed effective dose from the investigated radionuclides for each population group was well below the recommended value of 100 µSv y(-1), ranging from 4 to 7 µSv y(-1) for adults, from 8 to 10 µSv y(-1) for children and from 6 to 7 µSv y(-1) for infants. Of the investigated groups of the population children are the most exposed with the highest absolute doses of 19.1 and 18.7 µSv y(-1) after drinking a certain bottled brand of mineral and natural water, respectively. The contribution of each particular radionuclide to total doses varied among different water types and within each type, as well as between different age groups.

  11. [Contribution of natural mineral water to the iodine supply of the population].

    PubMed

    Kirchner, S; Stelz, A; Muskat, E

    1996-10-01

    Most parts of Germany are iodine deficiency areas. Daily iodine intake may be increased by food with high iodine content. Therefore determination of iodine in different foodstuffs is of importance. Aim of our work was to develop a method for mineral waters. Besides, we wanted to find out to what extent natural mineral waters can contribute to the iodine supply of the population. The method is based on the reaction of the halogenids iodide and bromide with ethylene oxide in a sulfuric acid medium while converting into 2-iodo- and 2-bromoethanol. After extraction, the reaction products are determined by capillary gas chromatography with an electron capture detector. The method was modified for mineral waters. Single results were confirmed by ICP-MS. For mineral waters the limits of determination are 3 micrograms/L for iodide and 42 micrograms/L for bromide. The investigation of mineral waters from Hessen showed, that only few sources contain iodide in remarkable amounts. Therefore a considerable improvement of iodide intake is possible only with single mineral waters.

  12. Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction

    SciTech Connect

    Elizabeth C. Chapman,† Rosemary C. Capo,† Brian W. Stewart,*,† Carl S. Kirby,‡ Richard W. Hammack,§ Karl T. Schroeder,§ and Harry M. Edenborn

    2012-02-24

    Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ∼375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (εSr SW = +13.8 to +41.6, where εSr SW is the deviation of the 87Sr/86Sr ratio from that of seawater in parts per 104); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

  13. Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction

    SciTech Connect

    Chapman, Elizabeth C; Capo, Rosemary C.; Stewart, Brian W.; Kirby, Carl S.; Hammack, Richard W.; Schroeder, Karl T.; Edenborn, Harry M.

    2012-03-20

    Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of 375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (ε{sub Sr}{sup SW} = +13.8 to +41.6, where ε{sub Sr}{sup SW} is the deviation of the {sup 87}Sr/{sup 86}Sr ratio from that of seawater in parts per 10{sup 4}); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

  14. Geochemical and strontium isotope characterization of produced waters from Marcellus Shale natural gas extraction.

    PubMed

    Chapman, Elizabeth C; Capo, Rosemary C; Stewart, Brian W; Kirby, Carl S; Hammack, Richard W; Schroeder, Karl T; Edenborn, Harry M

    2012-03-20

    Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ~375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (ε(Sr)(SW) = +13.8 to +41.6, where ε(Sr) (SW) is the deviation of the (87)Sr/(86)Sr ratio from that of seawater in parts per 10(4)); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters. PMID:22360406

  15. Metabolic regulation of amino acid uptake in marine waters

    SciTech Connect

    Kirchman, D.L.; Hodson, R.E.

    1986-03-01

    To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal waters of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In waters with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. Marine bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by marine bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis.

  16. Removal of natural organic matter from water using ion-exchange resins and cyclodextrin polyurethanes

    NASA Astrophysics Data System (ADS)

    Nkambule, T. I.; Krause, R. W.; Mamba, B. B.; Haarhoff, J.

    Natural organic matter (NOM) consists of a complex mixture of naturally occurring organic compounds. Although it is not considered toxic by itself, NOM present during water disinfection may result in the formation of disinfection by-products (DBPs), many of which are either carcinogenic or mutagenic. Although it is difficult to completely characterize NOM due to its complex and large structure, a consideration of its structure is necessary for a better understanding of the mechanism of NOM removal from water. In this study, water from the Vaalkop water treatment plant was characterized for its NOM composition by fractionation over ion-exchange resins. Fractionation at different pH with different resins resulted in the isolation of the neutral, basic and acidic fractions of both the hydrophobic and hydrophilic NOM. The hydrophilic basic fraction was found to be the most abundant fraction in the source water. Each of the isolated NOM fractions were percolated through cyclodextrin (CD) polyurethanes, resulting in an adsorption efficiency of between 6% and 33%. The acidic fractions were the most adsorbed fractions by the CD polyurethanes, while the neutral fractions being the least adsorbed. The water samples were then subjected to an ozonation regime at the treatment plant and then fractionated as before. As expected there were decreases of the neutral and basic fractions after ozonation. The application of CD polyurethanes to the fractions after ozonation resulted in a removal efficiency of up to 59%, nearly double that of the non-treated sample. Also, in the case of the ozone pre-treated samples, it was mainly the hydrophilic basic fraction which was removed. All the fractions were subjected to a chlorination test to determine the trihalomethane (THM) formation potential. All six NOM fractions resulted in THM formation, but the hydrophilic basic fraction was found to be the most reactive and formed the highest THM concentration. The effect of the combination of

  17. Natural chlorine and fluorine in the atmosphere, water and precipitation

    NASA Technical Reports Server (NTRS)

    Friend, James P.

    1990-01-01

    The geochemical cycles of chlorine and fluorine are surveyed and summarized as framework for the understanding of the global natural abundances of these species in the atmosphere, water, and precipitation. In the cycles the fluxes into and out of the atmosphere can be balanced within the limits of our knowledge of the natural sources and sinks. Sea salt from the ocean surfaces represent the predominant portion of the source of chlorine. It is also an important source of atmospheric fluorine, but volcanoes are likely to be more important fluorine sources. Dry deposition of sea salt returns about 85 percent of the salt released there. Precipitation removes the remainder. Most of the sea salt materials are considered to be cyclic, moving through sea spray over the oceans and either directly back to the oceans or deposited dry and in precipitation on land, whence it runs off into rivers and streams and returns to the oceans. Most of the natural chlorine in the atmosphere is in the form of particulate chloride ion with lesser amounts as gaseous inorganic chloride and methyl chloride vapor. Fluorine is emitted from volcanoes primarily as HF. It is possible that HF may be released directly form the ocean surface but this has not been confirmed by observation. HCl and most likely HF gases are released into the atmosphere by sea salt aerosols. The mechanism for the release is likely to be the provision of protons from the so-called excess sulfate and HNO3. Sea salt aerosol contains fluorine as F(-), MgF(+), CaF(+), and NaF. The concentrations of the various species of chlorine and fluorine that characterize primarily natural, unpolluted atmospheres are summarized in tables and are discussed in relation to their fluxes through the geochemical cycle.

  18. Geochemical Signature of Natural Water Recharge in the Jungar Basin and Its Response to Climate.

    PubMed

    Zhu, Bingqi; Yu, Jingjie; Rioual, Patrick

    2016-01-01

    This paper analyzed the physico-chemical characteristics of natural waters in a drainage system of the Jungar Basin, northwestern China to identify chemical evolution and recharge mechanisms of natural waters in an arid environment. The waters studied are different in mineralization, but are typically carbonate rivers and alkaline in nature. No Cl-dominated water type occurs, indicating an early stage of water evolution. Regolith and geomorphological parameters controlling ground-surface temperature may play a large role in the geological evolution of the water. Three main morphological and hydrological units are reflected in water physico-chemistry. Climate influences the salinization of natural waters substantially. Direct recharge from seasonal snow and ice-melt water and infiltration of rain to the ground are significant recharge processes for natural waters, but recharge from potential deep groundwater may be less important. The enrichment of ions in lakes has been mainly caused by evaporation rather than through the quality change of the recharged water.

  19. Determinants of cyanuric acid and melamine assembly in water.

    PubMed

    Ma, Mingming; Bong, Dennis

    2011-07-19

    While the recognition of cyanuric acid (CA) by melamine (M) and their derivatives has been known to occur in both water and organic solvents for some time, analysis of CA/M assembly in water has not been reported (Ranganathan, A.; Pedireddi, V. R.; Rao, C. N. R. J. Am. Chem. Soc.1999, 121, 1752-1753; Mathias, J. P.; Simanek, E. E.; Seto, C. T.; Whitesides, G. M. Macromol. Symp.1994, 77, 157-166; Zerkowski, J. A.; MacDonald, J. C.; Seto, C. T.; Wierda, D. A.; Whitesides, G. M. J. Am. Chem. Soc.1994, 116, 2382-2391; Mathias, J. P.; Seto, C. T.; Whitesides, G. M. Polym. Prepr.1993, 34, 92-93; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1993, 115, 905-916; Zerkowski, J. A.; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1992, 114, 5473-5475; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1990, 112, 6409-6411; Wang, Y.; Wei, B.; Wang, Q. J. Chem. Cryst.1990, 20, 79-84; ten Cate, M. G. J.; Huskens, J.; Crego-Calama, M.; Reinhoudt, D. N. Chem.-Eur. J.2004, 10, 3632-3639). We have examined assembly of CA/M, as well as assembly of soluble trivalent CA and M derivatives (TCA/TM), in aqueous solvent, using a combination of solution phase NMR, isothermal titration and differential scanning calorimetry (ITC/DSC), cryo-transmission electron microscopy (cryo-TEM), and synthetic chemistry. While the parent heterocycles coprecipitate in water, the trivalent system displays more controlled and cooperative assembly that occurs at lower concentrations than the parent and yields a stable nanoparticle suspension. The assembly of both parent and trivalent systems is rigorously 1:1 and proceeds as an exothermic, proton-transfer coupled process in neutral pH water. Though CA and M are considered canonical hydrogen-bonding motifs in organic solvents, we find that their assembly in water is driven in large part by enthalpically favorable surface-area burial, similar to what is observed with nucleic acid recognition. There are currently few synthetic systems capable of robust molecular

  20. Effect of natural dissolved organic carbon on phosphate removal by ferric chloride and aluminum sulfate treatment of wetland waters

    NASA Astrophysics Data System (ADS)

    Qualls, Robert G.; Sherwood, Lindsay J.; Richardson, Curtis J.

    2009-09-01

    The use of wetlands for the removal of excess N and P has become widespread. Some sensitive P-limited ecosystems, however, may require additional reductions in the concentration of P entering the system. It has been proposed that the treatment of wetlands through addition of ferric chloride or aluminum sulfate can augment the natural P removal mechanisms. However, high concentrations of natural dissolved organic matter may interfere with the removal of P by metal addition. We evaluated the doses of ferric chloride and aluminum sulfate necessary to reduce total P concentrations below 0.32 μM (10 μg/L) in water from the Northern Everglades, and we determined the effect of various concentrations (21, 38, and 60 mg/L) of natural dissolved organic carbon (DOC) on the removal of PO4 and total P. High concentrations of natural DOC inhibited both the short-term removal of PO4 and the longer-term removal of total P from the water column. Similar results were observed using 15 μM citric acid in an experiment to determine whether citric acid could effectively mimic the inhibition of phosphorus removal associated with natural DOC. Stoichiometry of these experiments indicates that the mechanism of natural DOC interference was not complexation of the metal ions by the DOC; we hypothesize that it could be adsorption to the terminal hydroxyl groups on a polynuclear Fe or Al colloid, effectively blocking the adsorption sites from a phosphate molecule. Also, the ability of citric acid to mimic the inhibitory effects also suggests that the results of the study are broadly applicable to wetland and other waters with high natural organic acid concentrations.

  1. Determination of formate in natural waters by a coupled enzymatic/high-performance liquid chromatographic technique

    SciTech Connect

    Kieber, D.J.; Vaughan, G.M.; Mopper, K.

    1988-09-01

    An enzymatic method was developed to quantify formic acid in natural water samples at submicromolar concentrations. The method is based on the oxidation of formate by formate dehydrogenase with corresponding reduction of ..beta..-nicotinamide adenine dinucleotide (..beta..-NAD/sup +/) to reduced ..beta..-NAD/sup +/ (..beta..-NADH); ..beta..-NADH is quantified by reversed-phase high-performance liquid chromatography with fluorometric detection. An important feature of this method is that the enzymatic reaction occurs directly in aqueous media, even sea water, and does not require sample pretreatment other than sample filtration. The reaction proceeds at room temperature at a slightly alkaline pH (7.5 - 8.5) and is specific for formate with a detection limit of 0.5 ..mu..M (S/N = 4) for a 200-..mu..L injection. The precision of the method was 4.6% relative standard deviation (n = 6) for a 0.6 ..mu..M standard addition of formate to Sargasso sea water. Average recoveries of 2 ..mu..M additions of formate to sea water, pore water, or rain were 103, 103, and 87%, respectively. Intercalibration with a Dionex ion chromatographic system showed an excellent agreement of 98%. Concentrations of formate present in natural samples ranged from 0.2 to 0.8 ..mu..M for Biscayne Bay sea water, 0.4 to 10.0 ..mu..M for Miami rain, and 0.9 to 8.4 ..mu..M for Biscayne Bay sediment pore water.

  2. The nature of the CO2- radical anion in water

    NASA Astrophysics Data System (ADS)

    Janik, Ireneusz; Tripathi, G. N. R.

    2016-04-01

    The reductive conversion of CO2 into industrial products (e.g., oxalic acid, formic acid, methanol) can occur via aqueous CO2- as a transient intermediate. While the formation, structure, and reaction pathways of this radical anion have been modelled for decades using various spectroscopic and theoretical approaches, we present here, for the first time, a vibrational spectroscopic investigation in liquid water, using pulse radiolysis time-resolved resonance Raman spectroscopy for its preparation and observation. Excitation of the radical in resonance with its 235 nm absorption displays a transient Raman band at 1298 cm-1, attributed to the symmetric CO stretch, which is at ˜45 cm-1 higher frequency than in inert matrices. Isotopic substitution at C (13CO2-) shifts the frequency downwards by 22 cm-1, which confirms its origin and the assignment. A Raman band of moderate intensity compared to the stronger 1298 cm-1 band also appears at 742 cm-1 and is assignable to the OCO bending mode. A reasonable resonance enhancement of this mode is possible only in a bent CO2-(C2v/Cs) geometry. These resonance Raman features suggest a strong solute-solvent interaction, the water molecules acting as constituents of the radical structure, rather than exerting a minor solvent perturbation. However, there is no evidence of the non-equivalence (Cs) of the two CO bonds. A surprising resonance Raman feature is the lack of overtones of the symmetric CO stretch, which we interpret due to the detachment of the electron from the CO2- moiety towards the solvation shell. Electron detachment occurs at the energies of 0.28 ± 0.03 eV or higher with respect to the zero point energy of the ground electronic state. The issue of acid-base equilibrium of the radical, which has been in contention for decades, as reflected in a wide variation in the reported pKa (-0.2 to 3.9), has been resolved. A value of 3.4 ± 0.2 measured in this work is consistent with the vibrational properties, bond structure

  3. The nature of the CO2 (-) radical anion in water.

    PubMed

    Janik, Ireneusz; Tripathi, G N R

    2016-04-21

    The reductive conversion of CO2 into industrial products (e.g., oxalic acid, formic acid, methanol) can occur via aqueous CO2 (-) as a transient intermediate. While the formation, structure, and reaction pathways of this radical anion have been modelled for decades using various spectroscopic and theoretical approaches, we present here, for the first time, a vibrational spectroscopic investigation in liquid water, using pulse radiolysis time-resolved resonance Raman spectroscopy for its preparation and observation. Excitation of the radical in resonance with its 235 nm absorption displays a transient Raman band at 1298 cm(-1), attributed to the symmetric CO stretch, which is at ∼45 cm(-1) higher frequency than in inert matrices. Isotopic substitution at C ((13)CO2 (-)) shifts the frequency downwards by 22 cm(-1), which confirms its origin and the assignment. A Raman band of moderate intensity compared to the stronger 1298 cm(-1) band also appears at 742 cm(-1) and is assignable to the OCO bending mode. A reasonable resonance enhancement of this mode is possible only in a bent CO2 (-)(C2v/Cs) geometry. These resonance Raman features suggest a strong solute-solvent interaction, the water molecules acting as constituents of the radical structure, rather than exerting a minor solvent perturbation. However, there is no evidence of the non-equivalence (Cs) of the two CO bonds. A surprising resonance Raman feature is the lack of overtones of the symmetric CO stretch, which we interpret due to the detachment of the electron from the CO2 (-) moiety towards the solvation shell. Electron detachment occurs at the energies of 0.28 ± 0.03 eV or higher with respect to the zero point energy of the ground electronic state. The issue of acid-base equilibrium of the radical, which has been in contention for decades, as reflected in a wide variation in the reported pKa (-0.2 to 3.9), has been resolved. A value of 3.4 ± 0.2 measured in this work is consistent with the vibrational

  4. Mammalian Cell Cytotoxicity and Genotoxicity of the Haloacetic Acids, A Major Class of Drinking Water Disinfection By-Products

    EPA Science Inventory

    The haloacetic acids (HAAs) are disinfection by-products (DBPs) that are formed during the disinfection of drinking water, wastewaters and recreational pool waters. Currently, five HAAs [bromoacetic acid (BAA), dibromoacetic acid (DBAA), chloroacetic acid (CAA), dichloroacetic ac...

  5. Trace metal speciation in natural waters: Computational vs. analytical

    USGS Publications Warehouse

    Kirk, Nordstrom D.

    1996-01-01

    Improvements in the field sampling, preservation, and determination of trace metals in natural waters have made many analyses more reliable and less affected by contamination. The speciation of trace metals, however, remains controversial. Chemical model speciation calculations do not necessarily agree with voltammetric, ion exchange, potentiometric, or other analytical speciation techniques. When metal-organic complexes are important, model calculations are not usually helpful and on-site analytical separations are essential. Many analytical speciation techniques have serious interferences and only work well for a limited subset of water types and compositions. A combined approach to the evaluation of speciation could greatly reduce these uncertainties. The approach proposed would be to (1) compare and contrast different analytical techniques with each other and with computed speciation, (2) compare computed trace metal speciation with reliable measurements of solubility, potentiometry, and mean activity coefficients, and (3) compare different model calculations with each other for the same set of water analyses, especially where supplementary data on speciation already exist. A comparison and critique of analytical with chemical model speciation for a range of water samples would delineate the useful range and limitations of these different approaches to speciation. Both model calculations and analytical determinations have useful and different constraints on the range of possible speciation such that they can provide much better insight into speciation when used together. Major discrepancies in the thermodynamic databases of speciation models can be evaluated with the aid of analytical speciation, and when the thermodynamic models are highly consistent and reliable, the sources of error in the analytical speciation can be evaluated. Major thermodynamic discrepancies also can be evaluated by simulating solubility and activity coefficient data and testing various

  6. Natural radioactivity in ground water near the Savannah River Site

    SciTech Connect

    Price, V. Jr. ); Michel, J. )

    1990-08-01

    A study of natural radioactivity in groundwater on and adjacent to the Savannah River Site (SRS) in Aiken (SC) was conducted to determine the spatial and temporal variations in the concentration of specific radionuclides. All available measurements for gross alpha particle activity, gross beta activity, uranium, Ra-226, Ra-228, and radon were collated. Relatively few radionuclide-specific results were found. Twenty samples from drinking water supplies in the area were collected in October 1987 and analyzed for U-238, U-234, Ra-226, Ra-228, and Rn-222. The aquifer type for each public water supply system was determined, and statistical analyses were conducted to detect differences among aquifer types and geographic areas defined at the country level. For samples from the public water wells and distribution systems on and adjacent to the site, most of the gross alpha particle activity could be attributed to Ra-226. Aquifer type was an important factor in determining the level of radioactivity in groundwater. The distribution and geochemical factors affecting the distribution of each radionuclide for the different aquifer types are discussed in detail. Statistical analyses were also run to test for aerial differences, among counties and the site. For all types of measurements, there were no differences in the distribution of radioactivity among the ten counties in the vicinity of the site or the site itself. The mean value for the plant was the lowest of all geographic areas for gross alpha particle activity and radon, intermediate for gross beta activity, and in the upper ranks for Ra-226 and Ra-228. It is concluded that the drinking water quality onsite is comparable with that in the vicinity. 19 refs., 5 figs., 5 tabs.

  7. Naturally Occurring Lactic Acid Bacteria Isolated from Tomato Pomace Silage

    PubMed Central

    Wu, Jing-jing; Du, Rui-ping; Gao, Min; Sui, Yao-qiang; Xiu, Lei; Wang, Xiao

    2014-01-01

    Silage making has become a significant method of forage conservation worldwide. To determine how tomato pomace (TP) may be used effectively as animal feed, it was ensilaged for 90 days and microbiology counts, fermentation characteristics and chemical composition of tomato pomace silage (TPS) were evaluated at the 30th, 60th, and 90th days, respectively. In addition, 103 lactic acid bacteria were isolated from TPS. Based on the phenotypic and chemotaxonomic characteristics, 16S rDNA sequence and carbohydrate fermentation tests, the isolates were identified as 17 species namely: Lactobacillus coryniformis subsp. torquens (0.97%), Lactobacillus pontis (0.97%), Lactobacillus hilgardii (0.97%), Lactobacillus pantheris (0.97%), Lactobacillus amylovorus (1.9%), Lactobacillus panis (1.9%), Lactobacillus vaginalis (1.9%), Lactobacillus rapi (1.9%), Lactobacillus buchneri (2.9%), Lactobacillus parafarraginis (2.9%), Lactobacillus helveticus (3.9%), Lactobacillus camelliae (3.9%), Lactobacillus fermentum (5.8%), Lactobacillus manihotivorans (6.8%), Lactobacillus plantarum (10.7%), Lactobacillus harbinensis (16.5%) and Lactobacillus paracasei subsp. paracasei (35.0%). This study has shown that TP can be well preserved for 90 days by ensilaging and that TPS is not only rich in essential nutrients, but that physiological and biochemical properties of the isolates could provide a platform for future design of lactic acid bacteria (LAB) inoculants aimed at improving the fermentation quality of silage. PMID:25049999

  8. Carbon isotope ratios in crassulacean Acid metabolism plants: seasonal patterns from plants in natural stands.

    PubMed

    Szarek, S R

    1976-09-01

    A year round study of photosynthesis and carbon isotope fractionation was conducted with plants of Opuntia phaeacantha Engelm. and Yucca baccata Torr. occurring in natural stands at elevations of 525, 970, 1450 and 1900 m. Plant water potentials and the daytime pattern of (14)CO(2) photosynthesis were similar for all cacti along the elevational gradient, despite significant differences in temperature regime and soil water status. Carbon isotope ratios of total tissue and soluble extract fractions were relatively constant throughtout the entire year. Additionally, the sigma(13)C values were similar in all plants of the same species along the elevational gradient, i.e. -12.5 +/- 0.86 per thousand for O. phaeacantha and -15.7 +/- 0.95 per thousand for Y. baccata. The results of this study indicate Crassulacean acid metabolism predominates as the major carbon pathway of these plants, which do not facultatively utilize the reductive pentose phosphate cycle of photosynthesis as the primary carboxylation reaction. PMID:16659680

  9. Tribromopyrrole, brominated acids, and other disinfection byproducts produced by disinfection of drinking water rich in bromide.

    PubMed

    Richardson, Susan D; Thruston, Alfred D; Rav-Acha, Chaim; Groisman, Ludmila; Popilevsky, Inna; Juraev, Olga; Glezer, Victor; McKague, A Bruce; Plewa, Michael J; Wagner, Elizabeth D

    2003-09-01

    Using gas chromatography/mass spectrometry (GC/MS), we investigated the formation of disinfection byproducts (DBPs) from high bromide waters (2 mg/L) treated with chlorine or chlorine dioxide used in combination with chlorine and chloramines. This study represents the first comprehensive investigation of DBPs formed by chlorine dioxide under high bromide conditions. Drinking water from full-scale treatment plants in Israel was studied, along with source water (Sea of Galilee) treated under carefully controlled laboratory conditions. Select DBPs (trihalomethanes, haloacetic acids, aldehydes, chlorite, chlorate, and bromate) were quantified. Many of the DBPs identified have not been previously reported, and several of the identifications were confirmed through the analysis of authentic standards. Elevated bromide levels in the source water caused a significant shift in speciation to bromine-containing DBPs; bromoform and dibromoacetic acid were the dominant DBPs observed, with very few chlorine-containing compounds found. Iodo-trihalomethanes were also identified, as well as a number of new brominated carboxylic acids and 2,3,5-tribromopyrrole, which represents the first time a halogenated pyrrole has been reported as a DBP. Most of the bromine-containing DBPs were formed during pre-chlorination at the initial reservoir, and were not formed by chlorine dioxide itself. An exception wasthe iodo-THMs, which appeared to be formed by a combination of chlorine dioxide with chloramines or chlorine (either added deliberately or as an impurity in the chlorine dioxide). A separate laboratory study was also conducted to quantitatively determine the contribution of fulvic acids and humic acids (from isolated natural organic matter in the Sea of Galilee) as precursor material to several of the DBPs identified. Results showed that fulvic acid plays a greater role in the formation of THMs, haloacetic acids, and aldehydes, but 2,3,5-tribromopyrrole was produced primarily from humic

  10. The geochemical behavior of natural radionuclides in coastal waters: A modeling study for the Huelva estuary

    NASA Astrophysics Data System (ADS)

    Periáñez, Raúl; Hierro, Almudena; Bolívar, Juan Pedro; Vaca, Federico

    2013-10-01

    A numerical model to study the behavior and distribution of natural radionuclides in sediments of an estuary (Odiel and Tinto rivers, SW Spain) affected by acid mine drainage and industrial activities has been developed. The model solves water circulation due to tides and river stream flows. The dispersion model includes uptake/release reactions of radionuclides between the dissolved phase and bed sediments in a dynamic way, using kinetic transfer coefficients. Seasonal pH and chlorinity distributions are simulated, and a formulation has been developed to consider these seasonal variations on kinetic coefficients. Calculated concentrations of 226Ra and 238U in sediments have been compared with measurements from four seasonal sampling campaigns. Numerical experiments have been carried out to study the relative significance of the different radionuclides sources into the estuary as well as the effect of the two components of water circulation (tides are river flows) on radionuclide dispersion patterns.

  11. DC diaphragm discharge in water solutions of selected organic acids

    NASA Astrophysics Data System (ADS)

    Vyhnankova, Edita J.; Hammer, Malte U.; Reuter, Stephan; Krcma, Frantisek

    2015-07-01

    Effect of four simple organic acids water solution on a DC diaphragm discharge was studied. Efficiency of the discharge was quantified by the hydrogen peroxide production determined by UV-VIS spectrometry of a H2O2 complex formed with specific titanium reagent. Automatic titration was used to study the pH behaviour after the plasma treatment. Optical emission spectroscopy overview spectra were recorded and detailed spectra of OH band and Hβ line were used to calculate the rotational temperature and comparison of the line profile (reflecting electron concentration) in the acid solutions. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  12. Disposal of acid gases with oilfield produced water

    SciTech Connect

    Duckworth, G.L.; Kopperson, D.; Horne, S.; Kohn, G.; Romansky, D.; Chan, C.

    1998-12-31

    With tightening environmental policies, many companies are investigating alternatives to atmospheric sulfur and greenhouse gas emissions. The oil and gas industry of Alberta, Canada typically recovers a high percentage of sulfur in large sour gas processing plants, but is often looking for a more cost effective approach to dealing with small volume plants. PanCanadian Petroleum Limited and DPH Engineering Inc. have developed a disposal scheme that makes low volume sour gas processing more affordable and easier to operate by disposing of acid gases in an aqueous phase to a disposal well. The development of this scheme utilized the results of reservoir studies, computer simulations, laboratory tests and field tests. This work has further resulted in the implementation of two full scale schemes to dissolve acid gas in produced water and inject it into deep subsurface formations. These schemes have operated with minimal problems and have met their environmental requirements.

  13. The effect of zeolite treatment by acids on sodium adsorption ratio of coal seam gas water.

    PubMed

    Wang, Xiaoyu; Ozdemir, Orhan; Hampton, Marc A; Nguyen, Anh V; Do, Duong D

    2012-10-15

    Many coal seam gas (CSG) waters contain a sodium ion concentration which is too high relative to calcium and magnesium ions for environment acceptance. Natural zeolites can be used as a cheap and effective method to control sodium adsorption ratio (SAR, which is a measure of the relative preponderance of sodium to calcium and magnesium) due to its high cation exchange capacity. In this study, a natural zeolite from Queensland was examined for its potential to treat CSG water to remove sodium ions to lower SAR and reduce the pH value. The results demonstrate that acid activated zeolite at 30%wt solid ratio can reduce the sodium content from 563.0 to 182.7 ppm; the pH from 8.74 to 6.95; and SAR from 70.3 to 18.5. Based on the results of the batch experiments, the sodium adsorption capacity of the acid-treated zeolite is three times greater than that of the untreated zeolite. Both the untreated and acid-treated zeolite samples were characterized using zeta potential, surface characterization, DTA/TG and particle size distribution in order to explain their adsorption behaviours.

  14. The effect of zeolite treatment by acids on sodium adsorption ratio of coal seam gas water.

    PubMed

    Wang, Xiaoyu; Ozdemir, Orhan; Hampton, Marc A; Nguyen, Anh V; Do, Duong D

    2012-10-15

    Many coal seam gas (CSG) waters contain a sodium ion concentration which is too high relative to calcium and magnesium ions for environment acceptance. Natural zeolites can be used as a cheap and effective method to control sodium adsorption ratio (SAR, which is a measure of the relative preponderance of sodium to calcium and magnesium) due to its high cation exchange capacity. In this study, a natural zeolite from Queensland was examined for its potential to treat CSG water to remove sodium ions to lower SAR and reduce the pH value. The results demonstrate that acid activated zeolite at 30%wt solid ratio can reduce the sodium content from 563.0 to 182.7 ppm; the pH from 8.74 to 6.95; and SAR from 70.3 to 18.5. Based on the results of the batch experiments, the sodium adsorption capacity of the acid-treated zeolite is three times greater than that of the untreated zeolite. Both the untreated and acid-treated zeolite samples were characterized using zeta potential, surface characterization, DTA/TG and particle size distribution in order to explain their adsorption behaviours. PMID:22841594

  15. The economic value of pelargonic acid as a natural herbicide in sweet bell peppers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Economic return on investment in respect to weed control management practices continue to be an essential element in use of naturally occurring substances for weed control in vegetable production. Pelargonic acid, although not certified as organic, is naturally occurring in many plants, animals, and...

  16. Natural products as biofuels and bio-based chemicals: fatty acids and isoprenoids.

    PubMed

    Beller, Harry R; Lee, Taek Soon; Katz, Leonard

    2015-09-23

    Although natural products are best known for their use in medicine and agriculture, a number of fatty acid-derived and isoprenoid natural products are being developed for use as renewable biofuels and bio-based chemicals. This review summarizes recent work on fatty acid-derived compounds (fatty acid alkyl esters, fatty alcohols, medium- and short-chain methyl ketones, alkanes, α-olefins, and long-chain internal alkenes) and isoprenoids, including hemiterpenes (e.g., isoprene and isopentanol), monoterpenes (e.g., limonene), and sesquiterpenes (e.g., farnesene and bisabolene).

  17. Water transport in water-in-oil-in-water liquid emulsion membrane system for the separation of lactic acid

    SciTech Connect

    Mok, Y.S.; Lee, W.K. )

    1994-03-01

    Liquid emulsion membranes (LEMs) were applied to the separation of lactic acid from an aqueous feed phase, and water transport (swelling) was investigated during the separation. Considering that as lactic acid was extracted into the internal stripping phase, osmotic pressure difference across the membrane was varied, the water transfer coefficient was evaluated. The water transfer coefficient was larger at higher carrier concentration and initial lactic acid concentration, which means that emulsion swelling can also be mediated by solute/carrier complexes although it is, in general, osmotically induced. The appropriate LEM formulation was given for separation and concentration of lactic acid. If both separation and concentration are desired, evidently emulsion swelling should be considered in conjunction with the transport rate of lactic acid. It was observed that the separated solute concentration in the internal phase was lowered due to swelling during the operation. Nevertheless, lactic acid could be concentrated in the internal phase more than 6 times in specific conditions, indicating that as the volume ratio of external phase to internal phase is increased, a still higher concentration in the internal phase can be obtained. 22 refs., 10 figs., 4 tabs.

  18. Uranium determination in natural water by the fissiontrack technique

    USGS Publications Warehouse

    Reimer, G.M.

    1975-01-01

    The fission track technique, utilizing the neutron-induced fission of uranium-235, provides a versatile analytical method for the routine analysis of uranium in liquid samples of natural water. A detector is immersed in the sample and both are irradiated. The fission track density observed in the detector is directly proportional to the uranium concentration. The specific advantages of this technique are: (1) only a small quantity of sample, typically 0.1-1 ml, is needed; (2) no sample concentration is necessary; (3) it is capable of providing analyses with a lower reporting limit of 1 ??g per liter; and (4) the actual time spent on an analysis can be only a few minutes. This paper discusses and describes the method. ?? 1975.

  19. Focussing the view on Nature's water-splitting catalyst

    SciTech Connect

    Messinger, Johannes; Yano, Junko

    2008-01-01

    About 3 billion years ago Nature invented a catalyst that splits water with highefficiency into molecular oxygen and hydrogen equivalents (protons and electrons). This reaction is energetically driven by sun light and the active centre contains relatively cheap and abundant metals: manganese and calcium. This biological system therefore forms the paradigm for all man made attempts for direct solar fuel production and several studies are underway to determine the electronic and geometric structures of this catalyst. In this report we briefly summarize the problems and the current status of these efforts, and propose a DFT-based strategy for obtaining a reliable high resolution structure of this unique catalyst that includes both the inorganic core and the first ligand sphere.

  20. Adaptation of sweeteners in water and in tannic acid solutions.

    PubMed

    Schiffman, S S; Pecore, S D; Booth, B J; Losee, M L; Carr, B T; Sattely-Miller, E; Graham, B G; Warwick, Z S

    1994-03-01

    Repeated exposure to a tastant often leads to a decrease in magnitude of the perceived intensity; this phenomenon is termed adaptation. The purpose of this study was to determine the degree of adaptation of the sweet response for a variety of sweeteners in water and in the presence of two levels of tannic acid. Sweetness intensity ratings were given by a trained panel for 14 sweeteners: three sugars (fructose, glucose, sucrose), two polyhydric alcohols (mannitol, sorbitol), two terpenoid glycosides (rebaudioside-A, stevioside), two dipeptide derivatives (alitame, aspartame), one sulfamate (sodium cyclamate), one protein (thaumatin), two N-sulfonyl amides (acesulfame-K, sodium saccharin), and one dihydrochalcone (neohesperidin dihydrochalcone). Panelists were given four isointense concentrations of each sweetener by itself and in the presence of two concentrations of tannic acid. Each sweetener concentration was tasted and rated four consecutive times with a 30 s interval between each taste and a 2 min interval between each concentration. Within a taste session, a series of concentrations of a given sweetener was presented in ascending order of magnitude. Adaptation was calculated as the decrease in intensity from the first to the fourth sample. The greatest adaptation in water solutions was found for acesulfame-K, Na saccharin, rebaudioside-A, and stevioside. This was followed by the dipeptide sweeteners, alitame and aspartame. The least adaptation occurred with the sugars, polyhydric alcohols, and neohesperidin dihydrochalcone. Adaptation was greater in tannic acid solutions than in water for six sweeteners. Adaptation of sweet taste may result from the desensitization of sweetener receptors analogous to the homologous desensitization found in the beta adrenergic system.

  1. Migration of humus substances from soil to water and the main chemical reaction (in different natural zone of Russian Federation)

    NASA Astrophysics Data System (ADS)

    Dinu, Marina; Moiseenko, Tatiana; Gashkina, Natalia; Kremleva, Tatiana

    2014-05-01

    recommendations ICP-Water report 105/2010, 2010. We researched HS from more then 10 soil sites in difference natural zone. The some lakes are characterized more than 100 water color ºPt-Co-scale and low pH waters (<4.5). These data are particularly important in evaluating the composition changing of HS in the water. Our experimental research has shown the changes in the qualitative composition of the HS and a ratio of their fractions by lowering the pH, especially, increasing the share of fulvic acids (Kola Peninsula territory). Change in the qualitative composition of HS is accompanied by a decrease in the molecular weight, the formation of additional free functional groups. This fact is crucial to the domination of the individual metals in natural waters of various natural zones. To study the complexation of HS in natural waters/soils we used «in situ» measurements and research process by chemical experiment. Most metals form in waters are more resistant as complexes with low molecular weight HS and in soil - vice versa. We discuses depending on the zonal specifics of HS mechanisms of complexation of each metal vary greatly. We show that the acidification processes in natural waters and soils contribute to the destruction of HS and consequently change the metals form.

  2. Water dispersible polytetrafluoroethylene microparticles prepared by grafting of poly(acrylic acid)

    NASA Astrophysics Data System (ADS)

    Yang, Changqiao; Xu, Lu; Zeng, Hongyan; Tang, Zhongfeng; Zhong, Lei; Wu, Guozhong

    2014-10-01

    Due to the hydrophobic nature and high gravimetric density, it is very difficult to obtain water dispersible polytetrafluoroethylene (PTFE) powder. In this work, hydrophilic PTFE microparticles were successfully prepared by grafting of poly(acrylic acid) onto PTFE micropowder via a pre-irradiation method. The as-obtained hydrophilic PTFE microparticles were analyzed by FT-IR, 1H NMR, CA, SEM and TGA. After neutralization by sodium hydroxide, the water contact angle decreased from 145.69° for pristine PTFE to 63.38° for PTFE-g-NaAA. The obtained micropowder can be easily dispersed in water to form a dispersion with very high stability. Furthermore, the presence of grafted PAA shows no obvious influence on degradation temperature of PTFE backbones.

  3. Acid-base chemistry of frustrated water at protein interfaces.

    PubMed

    Fernández, Ariel

    2016-01-01

    Water molecules at a protein interface are often frustrated in hydrogen-bonding opportunities due to subnanoscale confinement. As shown, this condition makes them behave as a general base that may titrate side-chain ammonium and guanidinium cations. Frustration-based chemistry is captured by a quantum mechanical treatment of proton transference and shown to remove same-charge uncompensated anticontacts at the interface found in the crystallographic record and in other spectroscopic information on the aqueous interface. Such observations are untenable within classical arguments, as hydronium is a stronger acid than ammonium or guanidinium. Frustration enables a directed Grotthuss mechanism for proton transference stabilizing same-charge anticontacts.

  4. Acid-base chemistry of frustrated water at protein interfaces.

    PubMed

    Fernández, Ariel

    2016-01-01

    Water molecules at a protein interface are often frustrated in hydrogen-bonding opportunities due to subnanoscale confinement. As shown, this condition makes them behave as a general base that may titrate side-chain ammonium and guanidinium cations. Frustration-based chemistry is captured by a quantum mechanical treatment of proton transference and shown to remove same-charge uncompensated anticontacts at the interface found in the crystallographic record and in other spectroscopic information on the aqueous interface. Such observations are untenable within classical arguments, as hydronium is a stronger acid than ammonium or guanidinium. Frustration enables a directed Grotthuss mechanism for proton transference stabilizing same-charge anticontacts. PMID:26762189

  5. Detecting acid precipitation impacts on lake water quality

    NASA Astrophysics Data System (ADS)

    Loftis, Jim C.; Taylor, Charles H.

    1989-09-01

    The United States Environmental Protection Agency is planning to expand its long-term monitoring of lakes that are sensitive to acid deposition effects. Effective use of resources will require a careful definition of the statistical objectives of monitoring, a network design which balances spatial and temporal coverage, and a sound approach to data analysis. This study examines the monitoring objective of detecting trends in water quality for individual lakes and small groups of lakes. Appropriate methods of trend analysis are suggested, and the power of trend detection under seasonal (quarterly) sampling is compared to that of annual sampling. The effects of both temporal and spatial correlation on trend detection ability are described.

  6. Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination.

    PubMed

    Bosire, G O; Ngila, J C; Parshotam, H

    2016-01-01

    The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™ X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges. PMID:27274730

  7. Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination.

    PubMed

    Bosire, G O; Ngila, J C; Parshotam, H

    2016-01-01

    The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™ X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges.

  8. Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination

    PubMed Central

    Bosire, G. O.; Ngila, J. C.; Parshotam, H.

    2016-01-01

    The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™ X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges. PMID:27274730

  9. Water Reserves Program. An adaptation strategy to balance water in nature

    NASA Astrophysics Data System (ADS)

    Lopez Perez, M.; Barrios, E.; Salinas-Rodriguez, S.; Wickel, B.; Villon, R. A.

    2013-05-01

    -allocation takes place. The strategy is to identify and protect basins with an availability of water that is close to their natural flow regime and that also have a high conservation value (based on prior national conservation priority definitions such as protected areas, and biodiversity conservation gap analyses) in order to implement legal restrictions on water resource development. With such protection, these systems will be best positioned to adjust and respond to water shortages, and regime shifts. To date, 189 basins around the country were identified as potential water reserves. The next step will be the nomination of these water reserves to be integrated in the National Water Reserves Program. This program forms the core of the official Mexican government adaptation strategy towards climate prepared water management, which recognizes that water reserves are the buffer society needs to face uncertainty, and reduce water scarcity risk. The development of activities that alter the natural flow regime such as dams and levees are closely examined, and would potentially be restricted.

  10. Inactivation of H1N1 viruses exposed to acidic ozone water

    NASA Astrophysics Data System (ADS)

    Uhm, Han S.; Lee, Kwang H.; Seong, Baik L.

    2009-10-01

    The inactivation of H1N1 viruses upon exposure to acidic ozone water was investigated using chicken allantoic fluids of different dilutions, pH values, and initial ozone concentrations. The inactivation effect of the acidic ozone water was found to be stronger than the inactivation effect of the ozone water combined with the degree of acidity, indicating a synergic effect of acidity on ozone decay in water. It is also shown that acidic ozone water with a pH value of 4 or less is very effective means of virus inactivation if provided in conjunction with an ozone concentration of 20 mg/l or higher.

  11. Characterization and disinfection by-product formation potential of natural organic matter in surface and ground waters from Northern Florida

    USGS Publications Warehouse

    Rostad, C.E.; Leenheer, J.A.; Katz, B.; Martin, B.S.; Noyes, T.I.

    2000-01-01

    Streamwaters in northern Florida have large concentrations of natural organic matter (NOM), and commonly flow directly into the ground water system through karst features, such as sinkholes. In this study NOM from northern Florida stream and ground waters was fractionated, the fractions characterized by infrared (IR) and nuclear magnetic resonance (NMR), and then chlorinated to investigate their disinfection by-product (DBP) formation potential (FP). As the NOM character changed (as quantified by changes in NOM distribution in various fractions, such as hydrophilic acids or hydrophobic neutrals) due to migration through the aquifer, the total organic halide (TOX)-FP and trihalomethane (THM)-FP yield of each of these fractions varied also. In surface waters, the greatest DBP yields were produced by the colloid fraction. In ground waters, DBP yield of the hydrophobic acid fraction (the greatest in terms of mass) decreased during infiltration.

  12. Interparticle collision of natural sediment grains in water

    USGS Publications Warehouse

    Schmeeckle, M.W.; Nelson, J.M.; Pitlick, J.; Bennett, J.P.

    2001-01-01

    Elastohydrodynamic theory and measurements of particle impacts on an inclined glass plane in water are used to investigate the mechanics of interparticle collisions in sediment-transporting flows. A collision Stokes number is proposed as a measure of the momentum of an interparticle collision versus the viscous pressure force in the interstitial gap between colliding particles. The viscous pressure force opposes motion of the particles on approach and rebound. A Stokes number of between 39 and 105 is estimated as the critical range below which particle impacts are completely viscously damped and above which impacts are partially elastic. The critical Stokes number is shown to roughly coincide with the Bagnold number transition between macroviscous and grain inertial debris flows and the transition between damped and partially elastic bed load transport saltation impacts. The nonspherical nature of natural particles significantly alters the motion of the center of mass after a partially elastic collision. The normal to the point of contact between the particles does not necessarily go through the center of mass. Thus normal rebound of the center of mass may not occur. A model of particle motion after rebound for particles of arbitrary shape, conserving both linear and angular momentum, is proposed.

  13. Selective detection and enumeration of fecal coliforms in water by potentiometric measurement of lipoic acid reduction.

    PubMed

    Jouenne, T; Junter, G A; Charriere, G

    1985-11-01

    Water samples of various origins were inoculated into a specific coliform-selective lactose broth provided with lipoic (thioctic) acid, and the time evolution of the redox potential of the cultures was monitored during incubation at 41 degrees C by use of gold versus reference electrodes. Positive potential-time responses, i.e., 100-mV potential shifts recorded within 20 h of inoculation, were related to the initial number of fecal coliforms in the broth determined by control enumeration techniques, and the organisms responsible were isolated and identified by conventional procedures. A total of 30 samples of wastewater, 38 of surface water, 553 of groundwater, and 110 of drinking water were tested successively. A total of 240 natural water samples, including 172 groundwater samples, and 1 drinking water sample were found to be positive in the potentiometric test. The majority (i.e., 92.5%) of the relevant potentiometric detection times were shorter than 15 h, and 96% of these could be attributed to Escherichia coli. Fifteen hours corresponded to the limit for detecting 1 E. coli cell per 100 ml of water. About 78% of the potentiometric responses occurring after 15 h were induced by fecal coliforms other than E. coli (Enterobacter cloacae, Klebsiella pneumoniae, and Citrobacter freundii). Calibration curves relating detection times shorter than 15 h to fecal coliform (i.e., E. coli) concentrations were constructed for the natural water samples tested. There were minor variations in the average growth rate of the organisms in the relation to the contamination level of the water tested. The number of false-positive samples in the potentiometric test was equivalent to that of false-negative samples (groundwater or drinking water).

  14. Terpolymers of ethyl acrylate/methacrylic acid/unsaturated acid ester of alcohols and acids as anti-settling agents in coal water slurries

    SciTech Connect

    Savoly, A.; Villa, J.L.; Grinstein, R.H.; Nachfolger, S.J.

    1988-05-17

    This patent describes a pumpable stabilized coal water slurry, having a coal content of at least about 50% by weight wherein at least 80% of the coal particles are about 200 mesh or finer, containing from about 0.01% to about 1% by weight of the slurry of a water soluble terpolymer of ethylacrylate (A), metacrylic acid (B) and a third monomer (C) selected from the group consisting of an unsaturated carboxylic acid ester of an alcohol and an ethoxylated carboxylic acid. The unsaturated carboxylic acid is a mono- or di- basic unsaturated carboxylic acid of 3 to 10 carbon atoms selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid.

  15. Natural attenuation of copper in the water table aquifer below an industrial site

    NASA Astrophysics Data System (ADS)

    Kedziorek, M. A.

    2003-12-01

    The contamination of soils and aquifers by inorganic pollutants is so extensive in industrial sites that it hardly seems economically feasible to decontaminate the large areas or soil volumes involved. It is therefore worthwhile to investigate whether the local environment is capable of attenuating contamination. Natural attenuation by degradation seems realistic for many organic pollutants. We show that it can also occur for inorganic pollutants. The phreatic-fill aquifer underlying an industrial plant located on the banks of the Garonne River (Southwestern France) is contaminated by acidic water (pH down to 1) and high concentrations of sulfate (up to 50 g/L) and copper (up to 30 g/L). As acidic water, rich in Cu and sulfate, moves away from the contamination source, pH increases due to buffering of aquifer solids, dissolved Cu concentrations decrease by 6 orders of magnitude, while sulfate concentrations decrease little. The Cu disappearing from the water phase is found as solid in cores in the area of the site where pH increases to 5-6.

  16. Emissions of the natural acidic substance in the acid rain region: Dimethyl sulfide and hydrogen sulfide in the region of Xiamen, China

    SciTech Connect

    Yubao Wang; Miaoqin Lu

    1996-12-31

    The global anthropogenic emissions of sulfur, mainly SO2, are relatively well studied for most of the industrialized world, and relatively little is known to date about natural sulfur emission sources, such as, coastal waters and wetland. The most important atmospheric sulfur compounds originating from biogeochemical sources are DMS and H{sub 2}S. Previous studies suggest that biogenic DMS is mainly emitted from oceanic phytoplankton species. The global emission of sulfur by this process was estimated to be 40 Tg S/year. Major sources of biogenic H{sub 2}S in the atmosphere are believed to be bacterial sulfate reduction in anoxic soils and degradation of organic matter. The mentioned reduced sulfur compounds are partially oxidation in the troposphere to SO{sub 2} and further to sulfur acid, another strong acid produced from DMS oxidation is methane sulphonic acid (CH{sub 3}S(O{sub 2})OH). These compounds are strong acid and will influence the pH of precipitation and will be the important impact in acid rain phenomena.

  17. The influence of organic acids in relation to acid deposition in controlling the acidity of soil and stream waters on a seasonal basis.

    PubMed

    Chapman, Pippa J; Clark, Joanna M; Reynolds, Brian; Adamson, John K

    2008-01-01

    Much uncertainty still exists regarding the relative importance of organic acids in relation to acid deposition in controlling the acidity of soil and surface waters. This paper contributes to this debate by presenting analysis of seasonal variations in atmospheric deposition, soil solution and stream water chemistry for two UK headwater catchments with contrasting soils. Acid neutralising capacity (ANC), dissolved organic carbon (DOC) concentrations and the Na:Cl ratio of soil and stream waters displayed strong seasonal patterns with little seasonal variation observed in soil water pH. These patterns, plus the strong relationships between ANC, Cl and DOC, suggest that cation exchange and seasonal changes in the production of DOC and seasalt deposition are driving a shift in the proportion of acidity attributable to strong acid anions, from atmospheric deposition, during winter to predominantly organic acids in summer.

  18. The influence of organic acids in relation to acid deposition in controlling the acidity of soil and stream waters on a seasonal basis.

    PubMed

    Chapman, Pippa J; Clark, Joanna M; Reynolds, Brian; Adamson, John K

    2008-01-01

    Much uncertainty still exists regarding the relative importance of organic acids in relation to acid deposition in controlling the acidity of soil and surface waters. This paper contributes to this debate by presenting analysis of seasonal variations in atmospheric deposition, soil solution and stream water chemistry for two UK headwater catchments with contrasting soils. Acid neutralising capacity (ANC), dissolved organic carbon (DOC) concentrations and the Na:Cl ratio of soil and stream waters displayed strong seasonal patterns with little seasonal variation observed in soil water pH. These patterns, plus the strong relationships between ANC, Cl and DOC, suggest that cation exchange and seasonal changes in the production of DOC and seasalt deposition are driving a shift in the proportion of acidity attributable to strong acid anions, from atmospheric deposition, during winter to predominantly organic acids in summer. PMID:17478019

  19. Influence of dissolved organic carbon content on modelling natural organic matter acid-base properties.

    PubMed

    Garnier, Cédric; Mounier, Stéphane; Benaïm, Jean Yves

    2004-10-01

    Natural organic matter (NOM) behaviour towards proton is an important parameter to understand NOM fate in the environment. Moreover, it is necessary to determine NOM acid-base properties before investigating trace metals complexation by natural organic matter. This work focuses on the possibility to determine these acid-base properties by accurate and simple titrations, even at low organic matter concentrations. So, the experiments were conducted on concentrated and diluted solutions of extracted humic and fulvic acid from Laurentian River, on concentrated and diluted model solutions of well-known simple molecules (acetic and phenolic acids), and on natural samples from the Seine river (France) which are not pre-concentrated. Titration experiments were modelled by a 6 acidic-sites discrete model, except for the model solutions. The modelling software used, called PROSECE (Programme d'Optimisation et de SpEciation Chimique dans l'Environnement), has been developed in our laboratory, is based on the mass balance equilibrium resolution. The results obtained on extracted organic matter and model solutions point out a threshold value for a confident determination of the studied organic matter acid-base properties. They also show an aberrant decreasing carboxylic/phenolic ratio with increasing sample dilution. This shift is neither due to any conformational effect, since it is also observed on model solutions, nor to ionic strength variations which is controlled during all experiments. On the other hand, it could be the result of an electrode troubleshooting occurring at basic pH values, which effect is amplified at low total concentration of acidic sites. So, in our conditions, the limit for a correct modelling of NOM acid-base properties is defined as 0.04 meq of total analysed acidic sites concentration. As for the analysed natural samples, due to their high acidic sites content, it is possible to model their behaviour despite the low organic carbon concentration.

  20. Mechanistic basis of adaptive maternal effects: egg jelly water balance mediates embryonic adaptation to acidity in Rana arvalis.

    PubMed

    Shu, Longfei; Suter, Marc J-F; Laurila, Anssi; Räsänen, Katja

    2015-11-01

    Environmental stress, such as acidification, can challenge persistence of natural populations and act as a powerful evolutionary force at ecological time scales. The ecological and evolutionary responses of natural populations to environmental stress at early life-stages are often mediated via maternal effects. During early life-stages, maternal effects commonly arise from egg coats (the extracellular structures surrounding the embryo), but the role of egg coats has rarely been studied in the context of adaptation to environmental stress. Previous studies on the moor frog Rana arvalis found that the egg coat mediated adaptive divergence along an acidification gradient in embryonic acid stress tolerance. However, the exact mechanisms underlying these adaptive maternal effects remain unknown. Here, we investigated the role of water balance and charge state (zeta potential) of egg jelly coats in embryonic adaptation to acid stress in three populations of R. arvalis. We found that acidic pH causes severe water loss in the egg jelly coat, but that jelly coats from an acid-adapted population retained more water than jelly coats from populations not adapted to acidity. Moreover, embryonic acid tolerance (survival at pH 4.0) correlated with both water loss and charge state of the jelly, indicating that negatively charged glycans influence jelly water balance and contribute to embryonic adaptation to acidity. These results indicate that egg coats can harbor extensive intra-specific variation, probably facilitated in part via strong selection on water balance and glycosylation status of egg jelly coats. These findings shed light on the molecular mechanisms of environmental stress tolerance and adaptive maternal effects.

  1. Mechanistic basis of adaptive maternal effects: egg jelly water balance mediates embryonic adaptation to acidity in Rana arvalis.

    PubMed

    Shu, Longfei; Suter, Marc J-F; Laurila, Anssi; Räsänen, Katja

    2015-11-01

    Environmental stress, such as acidification, can challenge persistence of natural populations and act as a powerful evolutionary force at ecological time scales. The ecological and evolutionary responses of natural populations to environmental stress at early life-stages are often mediated via maternal effects. During early life-stages, maternal effects commonly arise from egg coats (the extracellular structures surrounding the embryo), but the role of egg coats has rarely been studied in the context of adaptation to environmental stress. Previous studies on the moor frog Rana arvalis found that the egg coat mediated adaptive divergence along an acidification gradient in embryonic acid stress tolerance. However, the exact mechanisms underlying these adaptive maternal effects remain unknown. Here, we investigated the role of water balance and charge state (zeta potential) of egg jelly coats in embryonic adaptation to acid stress in three populations of R. arvalis. We found that acidic pH causes severe water loss in the egg jelly coat, but that jelly coats from an acid-adapted population retained more water than jelly coats from populations not adapted to acidity. Moreover, embryonic acid tolerance (survival at pH 4.0) correlated with both water loss and charge state of the jelly, indicating that negatively charged glycans influence jelly water balance and contribute to embryonic adaptation to acidity. These results indicate that egg coats can harbor extensive intra-specific variation, probably facilitated in part via strong selection on water balance and glycosylation status of egg jelly coats. These findings shed light on the molecular mechanisms of environmental stress tolerance and adaptive maternal effects. PMID:25983113

  2. Disinfection of Water Containing Natural Organic Matter by Using Ozone-Initiated Radical Reactions

    PubMed Central

    Cho, Min; Chung, Hyenmi; Yoon, Jeyong

    2003-01-01

    Ozone is widely used to disinfect drinking water and wastewater due to its strong biocidal oxidizing properties. Recently, it was reported that hydroxyl radicals (·OH), resulting from ozone decomposition, play a significant role in microbial inactivation when Bacillus subtilis endospores were used as the test microorganisms in pH controlled distilled water. However, it is not yet known how natural organic matter (NOM), which is ubiquitous in sources of drinking water, affects this process of disinfection by ozone-initiated radical reactions. Two types of water matrix were considered for this study. One is water containing humic acid, which is commercially available. The other is water from the Han River. This study reported that hydroxyl radicals, initiated by the ozone chain reaction, were significantly effective at B. subtilis endospore inactivation in water containing NOM, as well as in pH-controlled distilled water. The type of NOM and the pH have a considerable effect on the percentage of disinfection by hydroxyl radicals, which ranged from 20 to 50%. In addition, the theoretical \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}\\overline{C}\\end{equation*}\\end{document}T value of hydroxyl radicals for 2-log B. subtilis removal was estimated to be about 2.4 × 104 times smaller than that of ozone, assuming that there is no synergistic activity between ozone and hydroxyl radicals. PMID:12676711

  3. Physical and chemical effects of biochar on natural and artificial water repellent soils

    NASA Astrophysics Data System (ADS)

    Hallin, Ingrid; Douglas, Peter; Doerr, Stefan H.; Bryant, Rob; Matthews, Ian; Charbonneau, Cecile

    2014-05-01

    Water repellency (WR) affects soils worldwide. Hydrophobic compounds accumulate in soil through organic matter decomposition, microbial activity, condensation of organic compounds during vegetation fires, or through anthropogenic impacts such as oil spills. WR hinders vegetation establishment, which can lead to soil erosion and increased runoff. Biochar is currently being evaluated for its potential to increase soil carbon and as a soil amendment. To date, the effect of biochar on water repellent soils has remained largely undetermined. This study considered the potential of biochar as both a physical and chemical amendment for water repellent soils by asking two questions: does adding biochar reduce the observed degree of soil water repellency; and does biochar remove hydrophobic compounds from soil? The potential of biochar as a physical amendment to water repellent soils was evaluated by mixing 5, 10, 25 and 40% (by weight) each of coarse and fine ground biochar with two naturally water repellent soils and measuring the water drop penetration time (WDPT) for each mixture. Biochar particles beyond the range of existing soil particle diameters increased WDPT variability, which could be explained by increased surface roughness and the resulting enhancement of water repellency effects through Cassie-Baxter interactions. Overall, fine biochar was more effective at reducing water repellency: 25% w/w rendered both soils studied wettable. Removal of hydrophobic compounds by biochar was tested by mixing 1, 5, 10, 25 and 40% biochar with acid washed sand (AWS) coated with 1.2x10-5 mol octadecane and octadecanoic acid (per gram AWS, which corresponds to approximately 50 monolayers hydrophobic compound per gram AWS). Each mix stood for 1 to 30 days in a solution of pH 3, 6 or 9 before the AWS was extracted and the quantity of hydrophobic compound remaining determined by infrared spectroscopy and/or gas chromatography. Biochar successfully removed the hydrophobic compounds

  4. [Bactericidal effect of acidic electrolyzed water--comparison of chemical acidic sodium hydrochloride (NaOCl) solution].

    PubMed

    Iwasawa, A; Nakamura, Y

    1996-09-01

    Acidic electrolyzed water is made recently by various kinds of machines and is widely utilized. In this study, we intended to clarify the relationship between the concentration of chloride and pH in the bactericidal effects with acidic electrolyzed water. The effects of weak or strong acidic electrolyzed water were compared with a pseudo-acidic water of pH adjusted by diluted hydrochloric acid and sodium hydroxide, on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomononas aeruginosa. At pH 5.0 approximately 6.0, 3 bacterial strains were killed soon after being exposed to the acidic water containing chloride 50 mg/liter, and the amount of chloride did not change after allowing to stand open for 6 hours. At pH 2.67 approximately 2.80, the bactericidal effects was observed at the concentration of chloride 5 mg/liter, and 80% of chloride remained after allowing to stand for 6 hours. These results indicated that newly made strong acidic water is more effective under a smaller amount of chloride at pH 2.7, and that weak acidic electrolyzed water should be used, if stable bactericidal effect is expected in cleaning the surroundings. PMID:8921674

  5. Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films.

    PubMed

    Masamba, Kingsley; Li, Yue; Hategekimana, Joseph; Liu, Fei; Ma, Jianguo; Zhong, Fang

    2016-05-01

    In this study, the effect of gallic acid on mechanical and water barrier properties of zein-oleic acid 0-4 % composite films was investigated. Molecular weight distribution analysis was carried out to confirm gallic acid induced cross linking through change in molecular weight in fraction containing zein proteins. Results revealed that gallic acid treatment increased tensile strength from 17.9 MPa to 26.0 MPa, decreased water vapour permeability from 0.60 (g mm m(-2) h(-1) kPa(-1)) to 0.41 (g mm m(-2) h(-1) kPa(-1)), increased solubility from 6.3 % to 10.2 % and marginally increased elongation at break from 3.7 % to 4.2 % in zein films only. However, gallic acid treatment in zein-oleic composite films did not significantly influence mechanical and water barrier properties and in most instances irrespective of oleic acid concentration, the properties were negatively affected. Results from scanning electron microscopy showed that both gallic acid treated and untreated zein films and composite films containing 3 % oleic acid had a compact and homogeneous structure while those containing 4 % oleic acid had inhomogeneous structure. The findings have demonstrated that gallic acid treatment can significantly improve mechanical and water barrier properties especially in zein films only as opposed to when used in composite films using zein and oleic acid. PMID:27407188

  6. Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films.

    PubMed

    Masamba, Kingsley; Li, Yue; Hategekimana, Joseph; Liu, Fei; Ma, Jianguo; Zhong, Fang

    2016-05-01

    In this study, the effect of gallic acid on mechanical and water barrier properties of zein-oleic acid 0-4 % composite films was investigated. Molecular weight distribution analysis was carried out to confirm gallic acid induced cross linking through change in molecular weight in fraction containing zein proteins. Results revealed that gallic acid treatment increased tensile strength from 17.9 MPa to 26.0 MPa, decreased water vapour permeability from 0.60 (g mm m(-2) h(-1) kPa(-1)) to 0.41 (g mm m(-2) h(-1) kPa(-1)), increased solubility from 6.3 % to 10.2 % and marginally increased elongation at break from 3.7 % to 4.2 % in zein films only. However, gallic acid treatment in zein-oleic composite films did not significantly influence mechanical and water barrier properties and in most instances irrespective of oleic acid concentration, the properties were negatively affected. Results from scanning electron microscopy showed that both gallic acid treated and untreated zein films and composite films containing 3 % oleic acid had a compact and homogeneous structure while those containing 4 % oleic acid had inhomogeneous structure. The findings have demonstrated that gallic acid treatment can significantly improve mechanical and water barrier properties especially in zein films only as opposed to when used in composite films using zein and oleic acid.

  7. Solar Inactivation of Enterococci and Escherichia coli in Natural Waters: Effects of Water Absorbance and Depth.

    PubMed

    Maraccini, Peter A; Mattioli, Mia Catharine M; Sassoubre, Lauren M; Cao, Yiping; Griffith, John F; Ervin, Jared S; Van De Werfhorst, Laurie C; Boehm, Alexandria B

    2016-05-17

    The decay of sewage-sourced Escherichia coli and enterococci was measured at multiple depths in a freshwater marsh, a brackish water lagoon, and a marine site, all located in California. The marine site had very clear water, while the waters from the marsh and lagoon contained colored dissolved organic matter that not only blocked light but also produced reactive oxygen species. First order decay rate constants of both enterococci and E. coli were between 1 and 2 d(-1) under low light conditions and as high as 6 d(-1) under high light conditions. First order decay rate constants were well correlated to the daily average UVB light intensity corrected for light screening incorporating water absorbance and depth, suggesting endogenous photoinactivation is a major pathway for bacterial decay. Additional laboratory experiments demonstrated the presence of colored dissolved organic matter in marsh water enhanced photoinactivation of a laboratory strain of Enterococcus faecalis, but depressed photoinactivation of sewage-sourced enterococci and E. coli after correcting for UVB light screening, suggesting that although the exogenous indirect photoinactivation mechanism may be active against Ent. faecalis, it is not for the sewage-source organisms. A simple linear regression model based on UVB light intensity appears to be a useful tool for predicting inactivation rate constants in natural waters of any depth and absorbance. PMID:27119980

  8. Optical backscattering properties of the "clearest" natural waters

    NASA Astrophysics Data System (ADS)

    Twardowski, M. S.; Claustre, H.; Freeman, S. A.; Stramski, D.; Huot, Y.

    2007-11-01

    particulate backscattering bbp across the central gyre exhibited a broad particle peak centered ~100 m; -The particulate backscattering ratio typically ranged between 0.4% and 0.6% at 650 nm through the majority of the central gyre from the surface to ~210 m, indicative of "soft" water-filled particles with low bulk refractive index; and - bbp showed a distinct secondary deeper layer centered ~230 m that was absent in particulate attenuation cp data. The particulate backscattering ratio was significantly higher in this layer than in the rest of the water column, reaching 1.2% in some locations. This high relative backscattering, along with the pigment composition and ecological niche of this layer, appear to be consistent with the coccolithophorid Florisphaera profunda. Moreover, results were consistent with several expectations extrapolated from theory and previous work in oceanic and coastal regions, supporting the conclusion that particulate and total backscattering could be resolved in these extremely clear natural waters.

  9. Optical backscattering properties of the "clearest" natural waters

    NASA Astrophysics Data System (ADS)

    Twardowski, M. S.; Claustre, H.; Freeman, S. A.; Stramski, D.; Huot, Y.

    2007-07-01

    particulate backscattering bbp across the central gyre exhibited a broad particle peak centered ~100 m; - The particulate backscattering ratio typically ranged between 0.4% and 0.6% through the majority of the central gyre from the surface to ~210 m, indicative of "soft" water-filled particles with low bulk refractive index; and - bbp at 532 and 650 nm showed a distinct secondary deeper layer centered ~230 m that was absent in particulate attenuation cp data. The particulate backscattering ratio was significantly higher in this layer than in the rest of the water column, reaching 1.2% in some locations. This high relative backscattering, along with the pigment composition and ecological niche of this layer, appear to be consistent with the coccolithophorid F. profunda. Moreover, results were consistent with several expectations extrapolated from theory and previous work in oceanic and coastal regions, supporting the conclusion that particulate and total backscattering could be resolved in these extremely clear natural waters.

  10. Clinical Performance of a Dermal Filler Containing Natural Glycolic Acid and a Polylactic Acid Polymer

    PubMed Central

    Macchetto, Pedro Cervantes; Durán Páramo, Rosa Margarita

    2010-01-01

    Lipoatrophy is a condition that affects certain individuals, most commonly those who are infected with the human immunodeficiency virus.1–3 Injectable fillers are used for the treatment of these dermal contour deformities to smooth dermal depressions formed by the loss of volume. These dermal fillers (also known as soft tissue augmentation devices) can correct contour deformities caused by lipoatrophy in patients who are human immunodeficiency virus positive or negative. The product used in this study is a patented, second-generation, injectable, dermal collagen stimulator that combines glycolic acid and polylactic acid. The glycolic acid used is not a polymer, but rather an acid derived from sugar cane. Its chemical structure corresponds to that of an alpha-hydroxy acid. Glycolic acid is a well-characterized agent that is present in a number of cosmetic products. Polylactic acid is a synthetic, biocompatible, biodegradable, inert, synthetic polymer from the poly a-hydroxy-acid family that is believed to stimulate fibroblasts to produce more collagen, thus increasing facial volume. Together, polylactic acid and glycolic acid act in concert to 1) stimulate collagen production and 2) hydrate the outer layers of the skin. A multicenter, clinical investigation authorized by the Mexican Secretariat of Health was conducted between September 20, 2002, and September 19, 2004. This clinical study was conducted in male patients between 32 and 60 years of age with lipoatrophy as a result of highly active antiretroviral therapy for human immunodeficiency virus infection. The study objective was to measure the improvement of contour deformities after the injection of a dermal collagen stimulator containing glycolic acid and polylactic acid. In addition to safety, this dermal filler was assessed when used to correct volume deformities caused by lipoatrophy in subjects who are human immunodeficiency virus positive. Thirty male subjects participated and were treated as follows

  11. Photochemical degradation of marbofloxacin and enrofloxacin in natural waters.

    PubMed

    Sturini, Michela; Speltini, Andrea; Maraschi, Federica; Profumo, Antonella; Pretali, Luca; Fasani, Elisa; Albini, Angelo

    2010-06-15

    The photochemical fate of Marbofloxacin (MAR) and Enrofloxacin (ENR), two Fluoroquinolones (FQs) largely used as veterinary bactericides known to be present in surface waters, was investigated in aqueous solution. The degradation of these pollutants (5-50 microg L(-1) starting concentration) was complete in about 1 h by exposure to solar light (summer) and obeyed a first-order kinetics. The structure of the primary photoproducts was determined. Those from ENR arose through three paths, namely, oxidative degradation of the piperazine side-chain, reductive defluorination, and fluorine solvolysis. More heavily degraded products that had been previously reported were rationalized as secondary photoproducts from the present ones. As for MAR, this underwent homolytic cleavage of the tetrahydrooxadiazine moiety to give two quinolinols. All of the primary products were themselves degraded in about 1 h. The photoreactions rates were scarcely affected by Ca(2+) (200 mg L(-1)), Mg(2+) (30 mg L(-1)), Cl(-) (30 mg L(-1)), and humic acid (1 mg L(-1)), but increased in the presence of phosphate (20 mg L(-1)). The fastest degradation of ENR occurred at pH about 8 where the zwitterionic form was present, while in the case of MAR the cationic form was the most reactive.

  12. Organic acids in cloud water and rainwater at a mountain site in acid rain areas of South China.

    PubMed

    Sun, Xiao; Wang, Yan; Li, Haiyan; Yang, Xueqiao; Sun, Lei; Wang, Xinfeng; Wang, Tao; Wang, Wenxing

    2016-05-01

    To investigate the chemical characteristics of organic acids and to identify their source, cloud water and rainwater samples were collected at Mount Lu, a mountain site located in the acid rain-affected area of south China, from August to September of 2011 and March to May of 2012. The volume-weighted mean (VWM) concentration of organic acids in cloud water was 38.42 μeq/L, ranging from 7.45 to 111.46 μeq/L, contributing to 2.50 % of acidity. In rainwater samples, organic acid concentrations varied from 12.39 to 68.97 μeq/L (VWM of 33.39 μeq/L). Organic acids contributed significant acidity to rainwater, with a value of 17.66 %. Formic acid, acetic acid, and oxalic acid were the most common organic acids in both cloud water and rainwater. Organic acids had an obviously higher concentration in summer than in spring in cloud water, whereas there was much less discrimination in rainwater between the two seasons. The contribution of organic acids to acidity was lower during summer than during spring in both cloud water (2.20 % in summer vs 2.83 % in spring) and rainwater (12.24 % in summer vs 19.89 % in spring). The formic-to-acetic acid ratio (F/A) showed that organic acids were dominated by primary emissions in 71.31 % of the cloud water samples and whole rainwater samples. Positive matrix factorization (PMF) analysis determined four factors as the sources of organic acids in cloud water, including biogenic emissions (61.8 %), anthropogenic emissions (15.28 %), marine emissions (15.07 %) and soil emissions (7.85 %). The findings from this study imply an indispensable role of organic acids in wet deposition, but organic acids may have a limited capacity to increase ecological risks in local environments. PMID:26841776

  13. Organic acids in cloud water and rainwater at a mountain site in acid rain areas of South China.

    PubMed

    Sun, Xiao; Wang, Yan; Li, Haiyan; Yang, Xueqiao; Sun, Lei; Wang, Xinfeng; Wang, Tao; Wang, Wenxing

    2016-05-01

    To investigate the chemical characteristics of organic acids and to identify their source, cloud water and rainwater samples were collected at Mount Lu, a mountain site located in the acid rain-affected area of south China, from August to September of 2011 and March to May of 2012. The volume-weighted mean (VWM) concentration of organic acids in cloud water was 38.42 μeq/L, ranging from 7.45 to 111.46 μeq/L, contributing to 2.50 % of acidity. In rainwater samples, organic acid concentrations varied from 12.39 to 68.97 μeq/L (VWM of 33.39 μeq/L). Organic acids contributed significant acidity to rainwater, with a value of 17.66 %. Formic acid, acetic acid, and oxalic acid were the most common organic acids in both cloud water and rainwater. Organic acids had an obviously higher concentration in summer than in spring in cloud water, whereas there was much less discrimination in rainwater between the two seasons. The contribution of organic acids to acidity was lower during summer than during spring in both cloud water (2.20 % in summer vs 2.83 % in spring) and rainwater (12.24 % in summer vs 19.89 % in spring). The formic-to-acetic acid ratio (F/A) showed that organic acids were dominated by primary emissions in 71.31 % of the cloud water samples and whole rainwater samples. Positive matrix factorization (PMF) analysis determined four factors as the sources of organic acids in cloud water, including biogenic emissions (61.8 %), anthropogenic emissions (15.28 %), marine emissions (15.07 %) and soil emissions (7.85 %). The findings from this study imply an indispensable role of organic acids in wet deposition, but organic acids may have a limited capacity to increase ecological risks in local environments.

  14. Tracking the morphology of fulvic acids during water uptake

    NASA Astrophysics Data System (ADS)

    Zelenay, Veronika; Krepelova, Adela; Rudich, Yinon; Huthwelker, Thomas; Ammann, Markus

    2010-05-01

    Atmospheric humic like substances (HULIS) denote a range of oxidized, polyfunctional organic aerosol components widespread in the atmosphere, which show similar extraction behaviour on exchange columns as humic substances. Stemming from oxidation of primary gas phase and particulate organics, from e.g. biomass burning events, the HULIS constitute to a major fraction of the water soluble organic aerosol components in the atmosphere. Highly oxidized organic compounds play an important role in atmospheric processes like cloud formation or modification. Important factors therein are their hygroscopic properties and their microstructure, which influences their optical properties. HULIS somewhat resemble humic substances from terrestrial and aquatic sources, which consist mainly of carboxylic, aromatic and phenolic moieties assembled into hydrogen and van der Waals bonded supermolecular structures. Hence, the Suwannee River fulvic acid (SRFA), a chemically well characterized fulvic acid obtained from the International Humic Substances Society, was used to obtain combined data on hygroscopic properties and microstructural evolution during water uptake. The measurements were performed using x-ray absorption spectroscopy (NEXAFS, near edge x-ray absorption fine structure) in combination with an x-ray microscope (STXM, scanning x-ray transmission microscope) with a spatial resolution of about 30 nm. The measurements were performed at the PolLux beamline (SLS, Paul Scherrer Institut). The NEXAFS spectroscopy provides the possibility to map important chemical functional groups of carbon (as the one mentioned above) and oxygen atoms, and also to quantify the amount of carbon and oxygen atoms. To follow the submicron structure during water uptake a new device - a microreactor - was developed for the STXM. Using this reactor, the samples could be kept in a microenvironment with controlled temperature and humidity from 0 to 95 %. The samples were deposited either as droplets with

  15. Effects of natural phenolic acids on the skeletal system of ovariectomized rats.

    PubMed

    Folwarczna, Joanna; Zych, Maria; Burczyk, Jan; Trzeciak, Hanna; Trzeciak, Henryk I

    2009-12-01

    Recent reports indicate the possibility of antiresorptive and/or bone formation increasing activity of natural phenolic acids, commonly present in plants which are normally consumed in the diet. The effects of 4 natural phenolic acids (ferulic, caffeic, P-coumaric or chlorogenic, 10 mg/kg P. O. daily for 4 weeks) on the skeletal system of ovariectomized (estrogen-deficient) rats were investigated. Bone mass, mineral and calcium content, macrometric and histomorphometric parameters, and mechanical properties were examined. Phenolic acids differentially affected the skeletal system of rats with osteoporotic changes induced by the ovariectomy. Caffeic acid decreased bone mass, whereas P-coumaric acid increased the bone mass/body mass ratio and bone mineral mass/body mass ratio in the long bones, in comparison with the ovariectomized control rats. The phenolic acids improved some bone histomorphometric parameters, impaired by estrogen deficiency. However, they did not increase the ratio of bone mineral mass to bone mass, decreased by estrogen deficiency, and did not significantly affect bone mechanical properties. In conclusion, different natural phenolic acids exert differential effects on the skeletal system of ovariectomized rats, both favourable and deleterious.

  16. The Imbalance of Water in Nature as System

    NASA Astrophysics Data System (ADS)

    Kontar, V. A.; Imbalance of Water in Nature

    2011-12-01

    will not be obtained any reliable results. For example, the real water arrival occurs in the modes of imbalances such as increasing or decreasing. Water departure also is some set of the several imbalance increase and decrease types. The processes with various orientations interact between each other and reinforce or depress the conjoint effect. This creates some unstable situation, which are not visible by the balanced approach. Therefore some natural disasters actually are coming as unexpected. But in really there are some consequences of the methodological blindness. The Nature is unstable. The imbalance is the main state of the Nature. But mankind does not yet have adequate tools to describing imbalance as it is. In generally now is used more or less successful extrapolation and interpolation of the balance logic. But this is not enough now. So we tried to sharpen here the importance of the works with the imbalance directly.

  17. Theoretical considerations and a simple method for measuring alkalinity and acidity in low-pH waters by gran titration

    USGS Publications Warehouse

    Barringer, J.L.; Johnsson, P.A.

    1996-01-01

    Titrations for alkalinity and acidity using the technique described by Gran (1952, Determination of the equivalence point in potentiometric titrations, Part II: The Analyst, v. 77, p. 661-671) have been employed in the analysis of low-pH natural waters. This report includes a synopsis of the theory and calculations associated with Gran's technique and presents a simple and inexpensive method for performing alkalinity and acidity determinations. However, potential sources of error introduced by the chemical character of some waters may limit the utility of Gran's technique. Therefore, the cost- and time-efficient method for performing alkalinity and acidity determinations described in this report is useful for exploring the suitability of Gran's technique in studies of water chemistry.

  18. Monohaloacetic acid drinking water disinfection by-products inhibit follicle growth and steroidogenesis in mouse ovarian antral follicles in vitro.

    PubMed

    Jeong, Clara H; Gao, Liying; Dettro, Tyler; Wagner, Elizabeth D; Ricke, William A; Plewa, Michael J; Flaws, Jodi A

    2016-07-01

    Water disinfection greatly reduced the incidence of waterborne diseases, but the reaction between disinfectants and natural organic matter in water leads to the formation of drinking water disinfection by-products (DBPs). DBPs have been shown to be toxic, but their effects on the ovary are not well defined. This study tested the hypothesis that monohalogenated DBPs (chloroacetic acid, CAA; bromoacetic acid, BAA; iodoacetic acid, IAA) inhibit antral follicle growth and steroidogenesis in mouse ovarian follicles. Antral follicles were isolated and cultured with either vehicle or DBPs (0.25-1.00mM of CAA; 2-15μM of BAA or IAA) for 48 and 96h. Follicle growth was measured every 24h and the media were analyzed for estradiol levels at 96h. Exposure to DBPs significantly inhibited antral follicle growth and reduced estradiol levels compared to controls. These data demonstrate that DBP exposure caused ovarian toxicity in vitro. PMID:27151372

  19. Catalytic effect of water, formic acid, or sulfuric acid on the reaction of formaldehyde with OH radicals.

    PubMed

    Zhang, Weichao; Du, Benni; Qin, Zhenglong

    2014-07-01

    In this paper, for the hydrogen abstraction reaction of HCHO by OH radicals assisted by water, formic acid, or sulfur acid, the possible reaction mechanisms and kinetics have been investigated theoretically using quantum chemistry methods and transition-state theory. The potential energy surfaces calculated at the CCSD(T)/6-311++G(df,pd)//MP2(full)/6-311++G(df,pd) levels of theory reveal that, due to the formation of strong hydrogen bond(s), the relative energies of the transition states involving catalyst are significantly reduced compared to that reaction without catalyst. However, the kinetics calculations show that the rate constants are smaller by about 3, 9, or 10 orders of magnitude for water, formic acid, or sulfur acid assisted reactions than that uncatalyzed reaction, respectively. Consequently, none of the water, formic acid, or sulfur acid can accelerate the title reaction in the atmosphere.

  20. Continuous microcellular foaming of polylactic acid/natural fiber composites

    NASA Astrophysics Data System (ADS)

    Diaz-Acosta, Carlos A.

    Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. In spite of its excellent properties, commercial applications are limited because PLA is more expensive and more brittle than traditional petroleum-based resins. PLA can be blended with cellulosic fibers to reduce material cost. However, the lowered cost comes at the expense of flexibility and impact strength, which can be enhanced through the production of microcellular structures in the composite. Microcellular foaming uses inert gases (e.g., carbon dioxide) as physical blowing agents to make cellular structures with bubble sizes of less than 10 microm and cell-population densities (number of bubbles per unit volume) greater than 109 cells/cm³. These unique characteristics result in a significant increase in toughness and elongation at break (ductility) compared with unfoamed parts because the presence of small bubbles can blunt the crack-tips increasing the energy needed to propagate the crack. Microcellular foams have been produced through a two step batch process. First, large amounts of gas are dissolved in the solid plastic under high pressure (sorption process) to form a single-phase solution. Second, a thermodynamic instability (sudden drop in solubility) triggers cell nucleation and growth as the gas diffuses out of the plastic. Batch production of microcellular PLA has addressed some of the drawbacks of PLA. Unfortunately, the batch foaming process is not likely to be implemented in the industrial production of foams because it is not cost-effective. This study investigated the continuous microcellular foaming process of PLA and PLA/wood-fiber composites. The effects of the processing temperature and material compositions on the melt viscosity, pressure drop rate, and cell-population density were examined in order to understand the nucleation mechanisms in neat and filled PLA foams. The results indicated that

  1. Chemical speciation and adsorption behavior of plutonium in natural waters

    SciTech Connect

    Sanchez, A.L.

    1983-01-01

    Dissolved Pu profiles in two partially anoxic basins--Saanich Inlet, an intermittently anoxic marine fiord in Vancouver Island, British Columbia, and Soap Lake, a saline, alkaline lake in eastern Washington state, revealed minimum concentrations at the O/sub 2//H/sub 2/S interface. The Pu concentrations in the anoxic waters of Saanich Inlet were less than the surface concentrations; however, in Soap Lake, a 15- to 50-fold increase in Pu concentration in the anoxic monimolimnion correlated with large increases in the major ions, total alkalinity, and dissolved organic carbon. Laboratory experiments were designed to investigate the effects of pH, ionic strength, dissolved organic carbon, and carbonate ions on the adsorption of tracer amounts of Pu IV and Pu V. The Pu-goethite adsorption system provided the data base for developing a thermodynamic model of Pu interaction with an oxide surface and with dissolved ligands, using the MINEQL computer program. Pu IV and Pu V interacted very differently with goethite, which is consistent with their different hydrolytic character. A reduction of Pu V to Pu IV occurred on the goethite surface and also on montmorillonite and silica gel, suggesting that redox transformations are an important aspect of Pu adsorption. Increases in ionic strength (up to 3 M NaCl or NaNO/sub 3/) did not affect Pu IV or V adsorption. In the presence of dissolved organic carbon (DOC), Pu V reduction to Pu IV occurred in solution. Pu IV adsorption on goethite decreased only 30% in the presence of 240 ppm of natural DOC from Soap Lake; however, carbonate anions inhibited Pu IV adsorption on goethite at the alkalinity levels (1500 meq/L total alkalinity, 0.57 M CO/sub 3/=) measured for Soap Lake monimolimnion waters.

  2. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature.

    PubMed

    Norambuena, Fernando; Morais, Sofia; Emery, James A; Turchini, Giovanni M

    2015-01-01

    Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad-time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature

  3. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature

    PubMed Central

    Norambuena, Fernando; Morais, Sofia; Emery, James A.; Turchini, Giovanni M.

    2015-01-01

    Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad–time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature

  4. Natural Product Anacardic Acid from Cashew Nut Shells Stimulates Neutrophil Extracellular Trap Production and Bactericidal Activity.

    PubMed

    Hollands, Andrew; Corriden, Ross; Gysler, Gabriela; Dahesh, Samira; Olson, Joshua; Raza Ali, Syed; Kunkel, Maya T; Lin, Ann E; Forli, Stefano; Newton, Alexandra C; Kumar, Geetha B; Nair, Bipin G; Perry, J Jefferson P; Nizet, Victor

    2016-07-01

    Emerging antibiotic resistance among pathogenic bacteria is an issue of great clinical importance, and new approaches to therapy are urgently needed. Anacardic acid, the primary active component of cashew nut shell extract, is a natural product used in the treatment of a variety of medical conditions, including infectious abscesses. Here, we investigate the effects of this natural product on the function of human neutrophils. We find that anacardic acid stimulates the production of reactive oxygen species and neutrophil extracellular traps, two mechanisms utilized by neutrophils to kill invading bacteria. Molecular modeling and pharmacological inhibitor studies suggest anacardic acid stimulation of neutrophils occurs in a PI3K-dependent manner through activation of surface-expressed G protein-coupled sphingosine-1-phosphate receptors. Neutrophil extracellular traps produced in response to anacardic acid are bactericidal and complement select direct antimicrobial activities of the compound. PMID:27226531

  5. Natural Product Anacardic Acid from Cashew Nut Shells Stimulates Neutrophil Extracellular Trap Production and Bactericidal Activity.

    PubMed

    Hollands, Andrew; Corriden, Ross; Gysler, Gabriela; Dahesh, Samira; Olson, Joshua; Raza Ali, Syed; Kunkel, Maya T; Lin, Ann E; Forli, Stefano; Newton, Alexandra C; Kumar, Geetha B; Nair, Bipin G; Perry, J Jefferson P; Nizet, Victor

    2016-07-01

    Emerging antibiotic resistance among pathogenic bacteria is an issue of great clinical importance, and new approaches to therapy are urgently needed. Anacardic acid, the primary active component of cashew nut shell extract, is a natural product used in the treatment of a variety of medical conditions, including infectious abscesses. Here, we investigate the effects of this natural product on the function of human neutrophils. We find that anacardic acid stimulates the production of reactive oxygen species and neutrophil extracellular traps, two mechanisms utilized by neutrophils to kill invading bacteria. Molecular modeling and pharmacological inhibitor studies suggest anacardic acid stimulation of neutrophils occurs in a PI3K-dependent manner through activation of surface-expressed G protein-coupled sphingosine-1-phosphate receptors. Neutrophil extracellular traps produced in response to anacardic acid are bactericidal and complement select direct antimicrobial activities of the compound.

  6. Effect of ocean acidification on the fatty acid composition of a natural plankton community

    NASA Astrophysics Data System (ADS)

    Leu, E.; Daase, M.; Schulz, K. G.; Stuhr, A.; Riebesell, U.

    2012-07-01

    The effect of ocean acidification on the fatty acid composition of a natural plankton community in the Arctic was studied in a large-scale mesocosm experiment, carried out in Kongsfjorden (Svalbard, Norway) at 79° N. Nine mesocosms of ~50 cbm each were exposed to different pCO2 levels (from natural background conditions to ~1420 μatm), yielding pH values (on the total scale) from ~8.3 to 7.5. Inorganic nutrients were added on day 13. The phytoplankton development during this 30 days experiment passed three distinct phases: (1) prior to the addition of inorganic nutrients, (2) first bloom after nutrient addition, and (3) second bloom after nutrient addition. The fatty acid composition of the natural plankton community was analysed and showed, in general, high percentages of polyunsaturated fatty acids (PUFAs): 44-60% of total fatty acids. Positive correlations with pCO2 were found for most PUFAs during phases 2 and/or 3, with the exception of 20:5n3 (eicosapentaenoic acid, EPA), an important diatom marker. There are strong indications for these correlations being mediated indirectly through taxonomic changes and the natural development of the communities in the mesocosms exposed to different pCO2 levels. While diatoms increased during phase 3 mainly in the low and intermediate pCO2 treatments, dinoflagellates were favoured by high CO2 concentrations during the same time period. This is reflected in the development of group-specific fatty acid trophic markers. No indications were found for a generally detrimental effect of ocean acidification on the planktonic food quality in terms of essential fatty acids. The significant positive correlations between most PUFAs and pCO2 reflected treatment-dependent differences in the community composition between the mesocosms rather than a direct positive effect of pCO2 on specific fatty acids.

  7. Production of fatty acid butyl esters using the low cost naturally immobilized Carica papaya lipase.

    PubMed

    Su, Erzheng; Wei, Dongzhi

    2014-07-01

    In this work, the low cost naturally immobilized Carica papaya lipase (CPL) was investigated for production of fatty acid butyl esters (FABE) to fulfill the aim of reducing the lipase cost in the enzymatic butyl-biodiesel process. The CPL showed specificities to different alcohol acyl acceptors. Alcohols with more than three carbon atoms did not have negative effects on the CPL activity. The CPL catalyzed butanolysis for FABE production was systematically investigated. The reaction solvent, alcohol/oil molar ratio, enzyme amount, reaction temperature, and water activity all affected the butanolysis process. Under the optimized conditions, the highest conversion of 96% could be attained in 24 h. These optimal conditions were further applied to CPL catalyzed butanolysis of other vegetable oils. All of them showed very high conversion. The CPL packed-bed reactor was further developed, and could be operated continuously for more than 150 h. All of these results showed that the low cost Carica papaya lipase can be used as a promising lipase for biodiesel production.

  8. 1-Acetylpyrene-salicylic acid: photoresponsive fluorescent organic nanoparticles for the regulated release of a natural antimicrobial compound, salicylic acid.

    PubMed

    Barman, Shrabani; Mukhopadhyay, Sourav K; Behara, Krishna Kalyani; Dey, Satyahari; Singh, N D Pradeep

    2014-05-28

    Photoresponsive 1-acetylpyrene-salicylic acid (AcPy-SA) nanoparticles (NPs) were developed for the regulated release of a natural antimicrobial compound, salicylic acid. The strong fluorescent properties of AcPy-SA NPs have been extensively used for potential in vitro cell imaging. The phototrigger capability of our newly prepared AcPy-SA NPs was utilized for the efficient release of an antimicrobial compound, salicylic acid. The photoregulated drug release of AcPy-SA NPs has been shown by the subsequent switching off and on of a visible-light source. In vitro biological studies reveal that AcPy-SA NPs of ∼68 nm size deliver the antimicrobial drug salicylic acid into the bacteria cells (Pseudomonas aeruginosa) and efficiently kill the cells upon exposure to visible light (≥410 nm). Such photoresponsive fluorescent organic NPs will be highly beneficial for targeted and regulated antimicrobial drug release because of their biocompatible nature, efficient cellular uptake, and light-induced drug release ability.

  9. Stability of fluoride complex with silica and its distribution in natural water systems

    USGS Publications Warehouse

    Roberson, C.E.; Barnes, R.B.

    1978-01-01

    Fluoride reacts with silicic acid to form SiF2-6. A fluoride electrode was used to obtain an equilibrium constant of 1030.18 for the reaction:Si(OH) 0 6 + 6F-+4H+ = SiF 2- 6 + 4H2O at 25??C. Although there may be some experimental evidence for existence of traces of species containing less than six F- ions per silicon (n = 6), the species SiF2-6 predominates for n values from about 0.1 to 6. Silicic-acid complexing with fluoride is important only in solutions which have rather low pH and low concentrations of other cations which compete with silicon for fluoride. Computations for cold volcanic condensates from Hawaii indicate that for some samples much of the silicon is complexed by fluoride as SiF2-6. However, in most cooled acidic natural water samples Al and Fe are more important than Si in complexing fluoride. ?? 1978.

  10. Evaluation of different approaches to quantify strong organic acidity and acid-base buffering of organic-rich surface waters in Sweden.

    PubMed

    Köhler, Stephan; Hruska, Jakub; Jönsson, Jörgen; Lövgren, Lars; Lofts, Stephen

    2002-11-01

    The role of organic acids in buffering pH in surface waters has been studied using a small brownwater stream (26mg L(-1) TOC) draining a forested catchment in Northern Sweden. Under the conditions of elevated pressure of CO2 stream field pH was changed between 3.5 and 6.1 during the acidification and alkalinization experiment. Acid-base characteristics of the natural organic matter were also determined using a high precision potentiometric method for a concentrated sample from the same stream. We compared the predictions from the Windermere Humic Aqueous Model (WHAM Model V), a model derived from the potentiometric titration (diprotic/monoprotic acid model) and a previously derived triprotic acid model which only uses alkalinity and TOC as input variables. The predicted buffering characteristics of all three models are very similar in the pH range 4.5-7 which suggests that during routine analysis alkalinity and TOC are sufficient to give a good estimate of organic acid anion charge contribution in a large range of surface waters. A slightly adjusted version of WHAM V successfully describes the organic charge contribution in a large number of sampled surface water lakes, which were previously used to calibrate the triprotic model.

  11. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    DOEpatents

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

    2016-06-14

    Methods and systems for making dibasic esters and/or dibasic acids using metathesis are generally disclosed. In some embodiments, the methods comprise reacting a terminal olefin ester with an internal olefin ester in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In some embodiments, the terminal olefin ester or the internal olefin ester are derived from a renewable feedstock, such as a natural oil feedstock. In some such embodiments, the natural oil feedstock, or a transesterified derivative thereof, is metathesized to make the terminal olefin ester or the internal olefin ester.

  12. Engineering crassulacean acid metabolism to improve water-use efficiency

    PubMed Central

    Borland, Anne M.; Hartwell, James; Weston, David J.; Schlauch, Karen A.; Tschaplinski, Timothy J.; Tuskan, Gerald A.; Yang, Xiaohan; Cushman, John C.

    2014-01-01

    Climatic extremes threaten agricultural sustainability worldwide. One approach to increase plant water-use efficiency is to introduce crassulacean acid metabolism (CAM) into C3 crops. Such a task requires comprehensive systems-level understanding of the enzymatic and regulatory pathways underpinning this temporal CO2 pump. Here, we review the progress that has been made in achieving this goal. Given that CAM arose through multiple independent evolutionary origins, comparative transcriptomics and genomics of taxonomically diverse CAM species are being used to define the genetic ‘parts list’ required to operate the core CAM functional modules of nocturnal carboxylation, daytime decarboxylation, and inverse stomatal regulation. Engineered CAM offers the potential to sustain plant productivity for food, feed, fiber, and biofuel production in hotter and drier climates. PMID:24559590

  13. Shear rigidity of spread stearic acid monolayers on water

    SciTech Connect

    Abraham, B.M.; Ketterson, J.B.; Miyano, K.; Kueny, A.

    1981-09-15

    The effect of Al/sup 3 +/, Fe/sup 3 +/, Ca/sup 2 +/, and Mg/sup 2 +/ ions and of pH on the two-dimensional shear modulus of stearic acid spread on a water substrate was determined. A large shear modulus was displayed by the films when the subphase contained Al/sup 3 +/ and Fe/sup 3 +/ ions at the self-buffered pH. With Fe/sup 2 +/ dissolved in the subphase, the film displayed a viscous relaxation when strained but no residual stress was observed. No effect was observed with the Ca/sup 2 +/ or Mg/sup 2 +/. Reducing the pH value in the subphase with the trivalent ions caused the shear modulus to disappear. The observations are interpreted in terms of hydrogen bonding.

  14. Shear rigidity of spread stearic acid monolayers on water

    SciTech Connect

    Abraham, B.M.; Ketterson, J.B.; Miyano, K.; Kueny, A.

    1981-01-01

    The effect of Al/sup 3 +/, Fe/sup 3 +/, Ca/sup 2 +/, and Mg/sup 2 +/ ions and of pH on the two-dimensional shear modulus of stearic acid spread on a water substrate was determined. A large shear modulus was displayed by the films when the subphase contained Al/sup 3 +/ and Fe/sup 3 +/ ions at the self buffered pH. With Fe/sup 3 +/ dissolved in the subphase, the film displayed a viscous relaxation when strained but no residual stress was observed. No effect was observed with the Ca/sup 2 +/ or Mg/sup 2 +/. Reducing the pH value in the subphase with the trivalent ions caused the shear modulus to disappear. The observations are interpreted in terms of hydrogen bonding.

  15. [Study advance on haloacetic acids in drinking water].

    PubMed

    Ye, Bi-Xiong; Wang, Wu-Yi; Yang, Lin-Sheng; Wang, Yong-Hua

    2006-05-01

    Haloacetic acids (HAAs) in drinking water have attracted more and more attention of researchers due to their higher potential combination of chlorine, their carcinogenic and mutagenic effects and higher carcinogenic. The formation mechanism, analytical methods, the effects of many factors on HAAs formation such as precursor types, chlorine doses, pH, temperature, bromide, reaction time and seasonal change, toxicological character and the minimizing technology of HAAs in resent studies about HAAs are discussed in details in this paper. Further researches are still needed to clarify the formation mechanism of HAAs and find a feasible minimizing technology. New concerns including toxicological characters that correlate with human and other HAAs exposure routes besides oral ingestion (i.e., inhalation and dermal adsorption) should be put forward. PMID:16921773

  16. Organic nature of colloidal actinides transported in surface water environments.

    PubMed

    Santschi, Peter H; Roberts, Kimberly A; Guo, Laodong

    2002-09-01

    Elevated levels of (239,240)Pu and 241Am have been present in surficial soils of the Rocky Flats Environmental Technology Site (RFETS), CO, since the 1960s, when soils were locally contaminated in the 1960s by leaking drums stored on the 903 Pad. Further dispersion of contaminated soil particles was by wind and water. From 1998 until 2001, we examined actinide ((239,240)Pu and 241Am) concentrations and phase speciation in the surface environment at RFETS through field studies and laboratory experiments. Measurements of total (239,240)Pu and 241Am concentrations in storm runoff and pond discharge samples, collected during spring and summer times in 1998-2000, demonstrate that most of the (239,240)Pu and 241Am transported from contaminated soils to streams occurred in the particulate (> or = 0.45 microm; 40-90%) and colloidal (approximately 2 nm or 3 kDa to 0.45 microm; 10-60%) phases. Controlled laboratory investigations of soil resuspension, which simulated storm and erosion events, confirmed that most of the Pu in the 0.45 microm filter-passing phase was in the colloidal phase (> or = 80%) and that remobilization of colloid-bound Pu during soil erosion events can be greatly enhanced by humic and fulvic acids present in these soils. Most importantly, isoelectric focusing experiments of radiolabeled colloidal matter extracted from RFETS soils revealed that colloidal Pu is in the four-valent state and is mostly associated with a negatively charged organic macromolecule with a pH(IEP) of 3.1 and a molecular weight of 10-15 kDa, rather than with the more abundant inorganic (iron oxide and clay) colloids. This finding has important ramifications for possible remediation, erosion controls, and land-management strategies. PMID:12322742

  17. Proton and aluminum binding properties of organic acids in surface waters of the northeastern U.S.

    PubMed

    Fakhraei, Habibollah; Driscoll, Charles T

    2015-03-01

    A variety of mathematical estimators have been used to quantify the degree of protonation of naturally occurring organic acids. These estimators range from monoprotic, diprotic, and triprotic analog models to the discrete and continuous (Gaussian) distributions of a single proton binding-dissociation. Natural water samples from two long-term monitoring programs in the northeastern U.S. were used to quantify proton- and aluminum-binding properties of naturally occurring organic matter. Water chemistry observations were clustered into 0.05 pH intervals (over 3.75-7.35 pH range) and fit to a triprotic analog model. The model optimization indicates that about 5% of dissolved organic carbon participates in ion binding, and organic acids are composed of both strong and weak acids (i.e., pKa1 = 2.54, pKa2 = 6.19, and pKa3 = 7.52 for Adirondack samples). Binding between organic acids and aluminum can substantially influence the acid behavior of dissolved organic matter and the availability of the toxic form of aluminum (i.e., inorganic monomeric aluminum).

  18. Study on the kinetics and transformation products of salicylic acid in water via ozonation.

    PubMed

    Hu, Ruikang; Zhang, Lifeng; Hu, Jiangyong

    2016-06-01

    As salicylic acid is one of widely used pharmaceuticals, its residue has been found in various environmental water systems e.g. wastewater, surface water, treated water and drinking water. It has been reported that salicylic acid can be efficiently removed by advanced oxidation processes, but there are few studies on its transformation products and ozonation mechanisms during ozonation process. The objective of this study is to characterize the transformation products, investigate the degradation mechanisms at different pH, and propose the ozonation pathways of salicylic acid. The results showed that the rate of degradation was about 10 times higher at acidic condition than that at alkaline condition in the first 1 min when 1 mg L(-1) of ozone solution was added into 1 mg L(-1) of salicylic acid solution. It was proposed that ozone direct oxidation mechanism dominates at acidic condition, while indirect OH radical mechanism dominates at alkaline condition. A two stages pseudo-first order reaction was proposed at different pH conditions. Various hydroxylation products, carbonyl compounds and carboxylic acids, such as 2,5-dihydroxylbenzoic acid, 2,3-dihydroxylbenzoic acid, catechol, formaldehyde, glyoxal, acetaldehyde, maleic acid, acetic acid and oxalic acid etc. were identified as ozonation transformation products. In addition, acrylic acid was identified, for the first time, as ozonation transformation products through high resolution liquid chromatography-time of flight mass spectrometer. The information demonstrated in this study will help us to better understand the possible effects of ozonation products on the water quality. The degradation pathways of salicylic acid by ozonation in water sample were proposed. As both O3 and OH radical were important in the reactions, the degradation pathways of salicylic acid by ozonation in water sample were proposed at acidic and basic conditions. To our knowledge, there was no integrated study reported on the ozonation of

  19. Study on the kinetics and transformation products of salicylic acid in water via ozonation.

    PubMed

    Hu, Ruikang; Zhang, Lifeng; Hu, Jiangyong

    2016-06-01

    As salicylic acid is one of widely used pharmaceuticals, its residue has been found in various environmental water systems e.g. wastewater, surface water, treated water and drinking water. It has been reported that salicylic acid can be efficiently removed by advanced oxidation processes, but there are few studies on its transformation products and ozonation mechanisms during ozonation process. The objective of this study is to characterize the transformation products, investigate the degradation mechanisms at different pH, and propose the ozonation pathways of salicylic acid. The results showed that the rate of degradation was about 10 times higher at acidic condition than that at alkaline condition in the first 1 min when 1 mg L(-1) of ozone solution was added into 1 mg L(-1) of salicylic acid solution. It was proposed that ozone direct oxidation mechanism dominates at acidic condition, while indirect OH radical mechanism dominates at alkaline condition. A two stages pseudo-first order reaction was proposed at different pH conditions. Various hydroxylation products, carbonyl compounds and carboxylic acids, such as 2,5-dihydroxylbenzoic acid, 2,3-dihydroxylbenzoic acid, catechol, formaldehyde, glyoxal, acetaldehyde, maleic acid, acetic acid and oxalic acid etc. were identified as ozonation transformation products. In addition, acrylic acid was identified, for the first time, as ozonation transformation products through high resolution liquid chromatography-time of flight mass spectrometer. The information demonstrated in this study will help us to better understand the possible effects of ozonation products on the water quality. The degradation pathways of salicylic acid by ozonation in water sample were proposed. As both O3 and OH radical were important in the reactions, the degradation pathways of salicylic acid by ozonation in water sample were proposed at acidic and basic conditions. To our knowledge, there was no integrated study reported on the ozonation of

  20. Priming of plant resistance by natural compounds. Hexanoic acid as a model

    PubMed Central

    Aranega-Bou, Paz; de la O Leyva, Maria; Finiti, Ivan; García-Agustín, Pilar; González-Bosch, Carmen

    2014-01-01

    Some alternative control strategies of currently emerging plant diseases are based on the use of resistance inducers. This review highlights the recent advances made in the characterization of natural compounds that induce resistance by a priming mechanism. These include vitamins, chitosans, oligogalacturonides, volatile organic compounds, azelaic and pipecolic acid, among others. Overall, other than providing novel disease control strategies that meet environmental regulations, natural priming agents are valuable tools to help unravel the complex mechanisms underlying the induced resistance (IR) phenomenon. The data presented in this review reflect the novel contributions made from studying these natural plant inducers, with special emphasis placed on hexanoic acid (Hx), proposed herein as a model tool for this research field. Hx is a potent natural priming agent of proven efficiency in a wide range of host plants and pathogens. It can early activate broad-spectrum defenses by inducing callose deposition and the salicylic acid (SA) and jasmonic acid (JA) pathways. Later it can prime pathogen-specific responses according to the pathogen’s lifestyle. Interestingly, Hx primes redox-related genes to produce an anti-oxidant protective effect, which might be critical for limiting the infection of necrotrophs. Our Hx-IR findings also strongly suggest that it is an attractive tool for the molecular characterization of the plant alarmed state, with the added advantage of it being a natural compound. PMID:25324848

  1. Study on the removal of acid dyes using chitosan as a natural coagulant/coagulant aid.

    PubMed

    Zonoozi, M H; Alavi Moghaddam, M R; Arami, M

    2011-01-01

    Chitosan was selected as a natural coagulating agent for the removal of acid dyes (Acid Blue 292; AB292, and Acid Red 398; AR398) from dye-containing solutions. The study was organised in two phases. In phase 1, chitosan was used alone as a natural coagulant for the removal of the dyes. For this purpose, the effect of different parameters including pH, chitosan dosage and initial dye concentration on the dye removal efficiency was examined. In phase 2 of the study, the application of chitosan as a natural coagulant aid in conjunction with polyaluminium chloride (PAC) was assessed. According to the results of phase 1, the best removal efficiencies occurred in an acidic pH range (less than 6) for both of the dyes. Also, excellent dye removal results (about 90%) were achieved with relatively low dosages of chitosan (30-35 mg L(-1) for AB292 and 50-60 mg L(-1) for AR398). However, the initial concentration of the dyes severely influenced the coagulation performance of chitosan, which can constrain the performance of chitosan as a natural coagulant. On the basis of the results of phase 2, chitosan, as a natural coagulant aid, noticeably enhanced the dye removal efficiency of PAC, especially in the case of AB292. Small amounts of chitosan (3 or 5 mg L(-1)) enhanced the dye removal efficiency of PAC up to 2.5 times for AB292.

  2. The nature of nonfreezing water in carbohydrate polymers.

    PubMed

    Kocherbitov, Vitaly

    2016-10-01

    In an aqueous environment, carbohydrate polymers are surrounded by hydration shells consisting of water molecules that are sometimes called "bound". When polymer solutions are subjected to low temperatures, a part of water turns into ice, another part remains in the biopolymer phase and is called "nonfreezing water". Thermodynamic analysis of water freezing shows that the amount of non-freezing water does not reflect the amount of bound water, neither can it be used as a measure of strength of polymer-water interactions. Upon deep cooling, crystallization of water should desiccate polymers more than is observed in experiment. The reason for existence of non-freezing water is an interplay between the crystallization of water and the glass transition in biopolymers that prevents dehydration.

  3. The nature of nonfreezing water in carbohydrate polymers.

    PubMed

    Kocherbitov, Vitaly

    2016-10-01

    In an aqueous environment, carbohydrate polymers are surrounded by hydration shells consisting of water molecules that are sometimes called "bound". When polymer solutions are subjected to low temperatures, a part of water turns into ice, another part remains in the biopolymer phase and is called "nonfreezing water". Thermodynamic analysis of water freezing shows that the amount of non-freezing water does not reflect the amount of bound water, neither can it be used as a measure of strength of polymer-water interactions. Upon deep cooling, crystallization of water should desiccate polymers more than is observed in experiment. The reason for existence of non-freezing water is an interplay between the crystallization of water and the glass transition in biopolymers that prevents dehydration. PMID:27312645

  4. Antimicrobial activity and stability of weakly acidified chlorous acid water.

    PubMed

    Horiuchi, Isanori; Kawata, Hiroyuki; Nagao, Tamiko; Imaohji, Haruyuki; Murakami, Kazuya; Kino, Yasuhiro; Yamasaki, Hisashi; Koyama, A Hajime; Fujita, Yatsuka; Goda, Hisataka; Kuwahara, Tomomi

    2015-01-01

    The antimicrobial activity of weakly acidified chlorous acid water (WACAW) against Staphylococcus aureus, non-pathogenic Escherichia coli, enterohemorrhagic E. coli (EHEC O157:H7), Candida albicans, and spore-forming Bacillus and Paenibacillus species was evaluated in vitro. The antiviral activity was also examined using feline calicivirus (FCV). Diluted WACAW (>100 ppm) effectively reduced the number of non-spore-forming bacteria (>4 log10 CFU reductions) within 5 min. Treatment with this sanitizer at 400 ppm for 30 min achieved>5 log10 CFU reductions in spore-forming Bacillus and Paenibacillus species while an equivalent concentration of sodium hypochlorite (NaClO) resulted in only a 0.98 and 2.72 log10 CFU reduction, respectively. The effect of this sanitizer against FCV was equivalent to that of NaClO. Immersion in WACAW (400 ppm) achieved >4 and 2.26 log10 CFU reductions in Campylobacter jejuni and EHEC, respectively, on artificially contaminated broiler carcass pieces. Finally, theantimicrobial activity of this sanitizer was shown to be maintained for at least 28 d when in contact with nonwoven fabric (100% cotton). This study showed that pH control of chlorous acid is expected to modify its antimicrobial activity and stability. WACAW is expected to have applications in various settings such as the food processing and healthcare industries. PMID:25817812

  5. Supercooling versus crystallization of nitric acid/water aerosols

    SciTech Connect

    Disselkamp, R.S.; Anthony, S.E.; Tolbert, M.A.

    1995-12-31

    Polar Stratospheric Clouds (PSCs) have been implicated in Antarctic and Arctic ozone loss. These clouds are comprised of small particles (diameter {approximately}1 {mu}m) and play two essential roles in perturbing the chemistry of ozone during winter. First, PSCs promote heterogeneous reactions which activate chlorine. Second, PSCs permanently remove nitrogen oxides from the stratosphere due to particle sedimentation. Both PSC reactivity and denitrification depend on the particle phase and composition. In my talk, I will discuss laboratory modeling of PSCs. FTIR spectroscopy was used to investigate the phase and composition of nitric acid/water aerosols at temperatures from 190 to 229 K. Static aerosol samples were generated and probed spectroscopically for time periods of up to 100 minutes. For aerosols containing a molar ratio of 1:1 and 3:1 H{sub 2}O:HNO{sub 3}, extensive supercooling was observed with no crystallization in 100 minutes. However, aerosols containing a molar ratio of 2:1 H{sub 2}O:HNO{sub 3} crystallized readily to nitric acid dehydrate (NAD). The rate of NAD crystallization was found to increase with increasing temperature and will be discussed.

  6. Halogenated methanesulfonic acids: A new class of organic micropollutants in the water cycle.

    PubMed

    Zahn, Daniel; Frömel, Tobias; Knepper, Thomas P

    2016-09-15

    Mobile and persistent organic micropollutants may impact raw and drinking waters and are thus of concern for human health. To identify such possible substances of concern nineteen water samples from five European countries (France, Switzerland, The Netherlands, Spain and Germany) and different compartments of the water cycle (urban effluent, surface water, ground water and drinking water) were enriched with mixed-mode solid phase extraction. Hydrophilic interaction liquid chromatography - high resolution mass spectrometry non-target screening of these samples led to the detection and structural elucidation of seven novel organic micropollutants. One structure could already be confirmed by a reference standard (trifluoromethanesulfonic acid) and six were tentatively identified based on experimental evidence (chloromethanesulfonic acid, dichloromethanesulfonic acid, trichloromethanesulfonic acid, bromomethanesulfonic acid, dibromomethanesulfonic acid and bromochloromethanesulfonic acid). Approximated concentrations for these substances show that trifluoromethanesulfonic acid, a chemical registered under the European Union regulation REACH with a production volume of more than 100 t/a, is able to spread along the water cycle and may be present in concentrations up to the μg/L range. Chlorinated and brominated methanesulfonic acids were predominantly detected together which indicates a common source and first experimental evidence points towards water disinfection as a potential origin. Halogenated methanesulfonic acids were detected in drinking waters and thus may be new substances of concern. PMID:27267477

  7. Halogenated methanesulfonic acids: A new class of organic micropollutants in the water cycle.

    PubMed

    Zahn, Daniel; Frömel, Tobias; Knepper, Thomas P

    2016-09-15

    Mobile and persistent organic micropollutants may impact raw and drinking waters and are thus of concern for human health. To identify such possible substances of concern nineteen water samples from five European countries (France, Switzerland, The Netherlands, Spain and Germany) and different compartments of the water cycle (urban effluent, surface water, ground water and drinking water) were enriched with mixed-mode solid phase extraction. Hydrophilic interaction liquid chromatography - high resolution mass spectrometry non-target screening of these samples led to the detection and structural elucidation of seven novel organic micropollutants. One structure could already be confirmed by a reference standard (trifluoromethanesulfonic acid) and six were tentatively identified based on experimental evidence (chloromethanesulfonic acid, dichloromethanesulfonic acid, trichloromethanesulfonic acid, bromomethanesulfonic acid, dibromomethanesulfonic acid and bromochloromethanesulfonic acid). Approximated concentrations for these substances show that trifluoromethanesulfonic acid, a chemical registered under the European Union regulation REACH with a production volume of more than 100 t/a, is able to spread along the water cycle and may be present in concentrations up to the μg/L range. Chlorinated and brominated methanesulfonic acids were predominantly detected together which indicates a common source and first experimental evidence points towards water disinfection as a potential origin. Halogenated methanesulfonic acids were detected in drinking waters and thus may be new substances of concern.

  8. Transporters in Arabidopsis roots mediating uptake of amino acids at naturally occurring concentrations.

    PubMed

    Svennerstam, Henrik; Jämtgård, Sandra; Ahmad, Iftikhar; Huss-Danell, Kerstin; Näsholm, Torgny; Ganeteg, Ulrika

    2011-07-01

    Recent studies of Arabidopsis have identified several transporters as being important for amino acid uptake. We used Arabidopsis plants with altered expression of lysine histidine transporter 1 (LHT1), amino acid permease 1 (AAP1) and amino acid permease 5 (AAP5) with the aim of disentangling the roles of each transporter in the uptake of different amino acids at naturally occurring concentrations (2-50 μM). LHT1 mutants displayed reduced uptake rates of L-Gln, L-Ala, L-Glu and L-Asp but not of L-Arg or L-Lys, while AAP5 mutants were affected in the uptake of L-Arg and L-Lys only. Double mutants (lht1aap5) exhibited reduced uptake of all tested amino acids. In the concentration range tested, AAP1 mutants did not display altered uptake rates for any of the studied amino acids. Expression analysis of amino acid transporter genes with important root functions revealed no major differences in the individual mutants other than for genes targeted for mutation. We conclude that LHT1 and AAP5, but not AAP1, are crucial for amino acid uptake at concentrations typically found in soils. LHT1 and AAP5 displayed complementary affinity spectra, and no redundancy with respect to gene expression was found between the two transporters, suggesting these two transporters have separate roles in amino acid uptake.

  9. Effects of watering and simulated acid rain on quantity of phyllosphere fungi of birch leaves.

    PubMed

    Helander, M L; Rantio-Lehtimäki, A

    1990-01-01

    The effects of simulated acid rain on the population of birch phyllosphere fungi and species/genera/group composition of fungi on birch leaves were investigated in a field study in the subarctic region of northern Finland. The acid rain treatments consisted of a mixture of H2SO4 and HNO3 with a mass ratio of 2.86∶1 (S∶N) with acidities of pH 4 (A4) and pH 3 (A3). Dry control (DC) plots received only natural precipitation; irrigated control (IC) plots received spring water (pH 6) in a volume equal to the acid treatment plots. Treatments began in 1985. Culturing of the fungi inhabiting the birch leaves was performed five times during the summer of 1988. The number of fungal colonies was significantly decreased on one of five sampling dates in the pH 4 treatment and on three of five sampling dates in the pH 3 treatment. Irrigation with spring water did not have a significant effect. The acid rain treatments affected the microflora of the upper branches (at a height of 2 m) and of the lower branches (at a height of 0.5 m) equally. The lower branches had significantly more fungi than the upper ones on three of five sampling dates. The number of phyllosphere fungi isolated from birch leaves was greater in late summer than in early summer. The most abundant taxon (∼80%) wasAureobasidium pullulons, followed byHormonema sp. and zygomycetes.

  10. Encapsulation of ω-3 fatty acids in nanoemulsion-based delivery systems fabricated from natural emulsifiers: Sunflower phospholipids.

    PubMed

    Komaiko, Jennifer; Sastrosubroto, Ashtri; McClements, David Julian

    2016-07-15

    Nanoemulsions have considerable potential for encapsulating and delivering ω-3 fatty acids, but they are typically fabricated from synthetic surfactants. This study shows that fish oil-in-water nanoemulsions can be formed from sunflower phospholipids, which have advantages for food applications because they have low allergenicity and do not come from genetically modified organisms. Nanoemulsions containing small droplets (d<150 nm) could be produced using microfluidization, by optimizing phospholipid type and concentration, with the smallest droplets being formed at high phosphatidylcholine levels and at surfactant-to-oil ratios exceeding unity. The physical stability of the nanoemulsions was mainly attributed to electrostatic repulsion, with droplet aggregation occurring at low pH values (low charge magnitude) and at high ionic strengths (electrostatic screening). These results suggest that sunflower phospholipids may be a viable natural emulsifier to deliver ω-3 fatty acids into food and beverage products.

  11. Encapsulation of ω-3 fatty acids in nanoemulsion-based delivery systems fabricated from natural emulsifiers: Sunflower phospholipids.

    PubMed

    Komaiko, Jennifer; Sastrosubroto, Ashtri; McClements, David Julian

    2016-07-15

    Nanoemulsions have considerable potential for encapsulating and delivering ω-3 fatty acids, but they are typically fabricated from synthetic surfactants. This study shows that fish oil-in-water nanoemulsions can be formed from sunflower phospholipids, which have advantages for food applications because they have low allergenicity and do not come from genetically modified organisms. Nanoemulsions containing small droplets (d<150 nm) could be produced using microfluidization, by optimizing phospholipid type and concentration, with the smallest droplets being formed at high phosphatidylcholine levels and at surfactant-to-oil ratios exceeding unity. The physical stability of the nanoemulsions was mainly attributed to electrostatic repulsion, with droplet aggregation occurring at low pH values (low charge magnitude) and at high ionic strengths (electrostatic screening). These results suggest that sunflower phospholipids may be a viable natural emulsifier to deliver ω-3 fatty acids into food and beverage products. PMID:26948622

  12. Monitored Natural Attenuation For Inorganic Contaminants In Ground Water - Technical Issues

    EPA Science Inventory

    Remediation of ground water contaminated with radionuclides may be achieved using attenuation-based technologies. These technologies may rely on engineered processes (e.g., bioremediation) or natural processes (e.g., monitored natural attenuation) within the subsurface. In gene...

  13. Selective removal of copper (II) from natural waters by nanoporous sorbents functionalized with chelating diamines

    SciTech Connect

    Chouyyok, Wilaiwan; Shin, Yongsoon; Davidson, Joseph D.; Samuels, William D.; LaFemina, Nikki H.; Rutledge, Ryan D.; Fryxell, Glen E.; Sangvanich, Thanapon; Yantasee, Wassana

    2010-04-13

    The essential trace metal copper has been identified as a pollutant of concern by the Environmental Protection Agency (EPA) because of its widespread occurrence in the environment, often being found in concentrations capable of causing problems in organisms in that ecosystem. In this work, three different nanoporous sorbents containing chelating diamine functionalities were evaluated for Cu2+ adsorption in natural waters; these sorbents are ethylenediamine functionalized self-assembled monolayers on mesoporous supports (EDA-SAMMS®, SAMMS is a registered trademark of Steward Advanced Materials), ethylenediamine functionalized activated carbon (AC-CH2-EDA), and 1,10-Phenanthroline functionalized mesoporous carbon (Phen-FMC). The pH dependence of Cu2+ sorption and the Cu2+ sorption capacities of sorbents were determined. The Cu2+ adsorption rates and metal ion selectivity of these sorbents were compared to those of commercial sorbents (Chelex-100 ion exchange resin and Darco KB-B activated carbon). All three chelating diamine sorbents showed the excellent Cu2+ removal (~ 95-99%) from river water and sea water over the pH range of 6.0-8.0. Even under acidic conditions (e.g. pH of 3), AC-CH2-EDA and Phen-FMC were able to remove approximately ~49-58% of Cu2+ in sea water. EDA-SAMMS and AC-CH2-EDA demonstrated rapid Cu2+ sorption kinetics (reaching equilibrium within 5 min) and large adsorption capacities (26 and 17 mg Cu/g sorbent, respectively) in sea water. They also showed good selectivity for Cu2+ over other metal ions (e.g. Ca2+, Fe2+, Ni2+, and Zn2+) in sea water.

  14. The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.

    PubMed

    Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

    2015-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15 mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20 mg/l) was broader than that of acid-soluble chitosan (4-8 mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water. PMID:25362971

  15. Improving and testing geochemical speciation predictions of metal ions in natural waters.

    PubMed

    Ahmed, Imad A M; Hamilton-Taylor, John; Bieroza, Magdalena; Zhang, Hao; Davison, William

    2014-12-15

    The ability of WHAM VII and NICA-Donnan models to predict free-ion activities of Cu in natural waters was examined from two perspectives, (i) the presence of EDTA and NTA contaminants, (ii) the need to improve estimates of HA and FA concentrations. Potentiometric responses of a Cu(II) ion-selective electrode were investigated in five assays containing dissolved organic matter (DOM) isolated from a series of polluted (urban) and relatively unpolluted (upland) streams in northern England. The [Cu]/[DOC] ratio in these assays spanned an environmentally realistic range of ∼1-500 μmol/g. Reasonably good agreement between measured and predicted Cu(2+) activities was obtained with both WHAM VII and NICA-Donnan models, assuming 65% of DOM as fulvic acid and including the measured EDTA and NTA concentrations, but generally the models overestimated the activities by a factor of ∼2. In contrast, the models over-predicted the Cu(2+) activities by up to 2 orders of magnitude at low [Cu]/[DOC] ratios in urban waters if anthropogenic ligands were not included in the model simulations. Three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy was used to measure the functional properties of the isolated DOM and to estimate the fractions of FA and HA present. Using these fractions in the models gave improvements in predictions compared to the 65% FA assumption, as shown by higher correlations, reduced error and reduced bias. These results highlight various issues with the use of the available speciation models for predicting free ion concentrations in natural waters, such as the use of the Biotic Ligand Model (BLM) for the derivation of environmental standards. It is clearly necessary to measure EDTA and NTA in waters with urban influences, while fluorescence measurements offer the possibility of appreciably improving the accuracy of predictions.

  16. Refuges from ocean acidification: determining tolerances of coralline algae to naturally low-pH water

    NASA Astrophysics Data System (ADS)

    Cooper, H.; Paytan, A.; Potts, D. C.

    2014-12-01

    Anthropogenic carbon dioxide dissolving into the world's oceans is causing a profound and rapid shift in ocean chemistry referred to as ocean acidification (OA) that causes carbonate structures to dissolve more readily in seawater with negative effects for organisms relying on calcified skeletons or shells (e.g. corals, mollusks, coralline algae). Crustose coralline algae (CCA) are ubiquitous and essential on coral reefs, providing both ecological and structural benefits to the reefs. However, CCA are adversely affected by low pH water, with severe reductions in recruitment, survival, growth and productivity. The ability of different species of CCA to adapt to low pH waters was tested using a system of natural submarine springs (called "ojos") near Puerto Morelos on the Yucatan Peninsula, Mexico. These ojos continuously discharge groundwater that is close to seawater salinity but more acidic (pH 6.70-7.30) and under saturated (0.3 Ω to 0.97 Ω) than the ambient seawater (pH 8.03, 3.60 Ω ). Both corals and coralline algae grow in the water from these springs, suggesting that some calcifying species differ in their tolerance to low pH waters. Corallines were sampled along a pH gradient at five springs in December 2013 using underwater transects. Differences in percent cover, species abundance and diversity of CCA by pH levels will be discussed. This work utilizes a unique natural laboratory for studying properties of calcifying biota along pH gradients and provides insight into the ability of CCA to tolerate or adapt to future conditions.

  17. Copper corrosion in potable water systems: Impacts of natural organic matter and water treatment processes

    SciTech Connect

    Rehring, J.P.; Edwards, M.

    1996-04-01

    Copper corrosion was examined in the presence of natural organic matter (NOM) and in situations where NOM was altered by drinking water treatment. Corrosion rates (i{sub corr}) increased with higher NOM concentration at pH 6, whereas insignificant effects were observed at pH 7.5 and 9.0. Corrosion byproduct release was affected adversely by 4 mg/L NOM at pH 6.0, 7.5 and 9.0, with soluble copper increasing by 0.6 mg/L to 0.7 mg/L when compared to solutions without NOM. Alum-coagulated waters had higher i{sub corr} than untreated waters, but ferric chloride (FeCl{sub 3}{center_dot}6H{sub 2}O)-coagulated waters exhibited reduced i{sub corr}. This difference was attributed to the relative effects of added sulfate via alum coagulation vs added chloride via FeCl{sub 3}{center_dot}6H{sub 2}O coagulation. The effect of combined treatment (alum coagulation, ozonation, and granular activated carbon) was similar to that using alum coagulation alone.

  18. Ion exchange separation of chromium from natural water matrix for stable isotope mass spectrometric analysis

    USGS Publications Warehouse

    Ball, J.W.; Bassett, R.L.

    2000-01-01

    A method has been developed for separating the Cr dissolved in natural water from matrix elements and determination of its stable isotope ratios using solid-source thermal-ionization mass spectrometry (TIMS). The separation method takes advantage of the existence of the oxidized form of Cr as an oxyanion to separate it from interfering cations using anion-exchange chromatography, and of the reduced form of Cr as a positively charged ion to separate it from interfering anions such as sulfate. Subsequent processing of the separated sample eliminates residual organic material for application to a solid source filament. Ratios for 53Cr/52Cr for National Institute of Standards and Technology Standard Reference Material 979 can be measured using the silica gel-boric acid technique with a filament-to-filament standard deviation in the mean 53Cr/52Cr ratio for 50 replicates of 0.00005 or less. (C) 2000 Elsevier Science B.V. All rights reserved.

  19. Field measurements of the spectral response of natural waters

    NASA Technical Reports Server (NTRS)

    Bartolucci, L. A.; Robinson, B. F.; Silva, L. F.

    1977-01-01

    The spectral response (air-water interface reflectance and water-volume scattering) of turbid river water (99 mg/liter suspended solids) and relatively clear lake water (10 mg/liter suspended solids) was measured in situ with a field spectroradiometer. The influence of the river bottom on the spectral response of the water also was determined by using a modified Secchi disc approach. The results indicated that turbid river water had a higher spectral response than clear lake water (about 6 percent) in the red (0.6-0.7 micron) and near-infrared (0.7-0.9 micron) portions of the spectrum. Also, the reflectance characteristics of the river bottom did not influence the spectral response of the turbid river water when the water was deeper than 30 cm

  20. Natural fatty acid synthase inhibitors as potent therapeutic agents for cancers: A review.

    PubMed

    Zhang, Jia-Sui; Lei, Jie-Ping; Wei, Guo-Qing; Chen, Hui; Ma, Chao-Ying; Jiang, He-Zhong

    2016-09-01

    Context Fatty acid synthase (FAS) is the only mammalian enzyme to catalyse the synthesis of fatty acid. The expression level of FAS is related to cancer progression, aggressiveness and metastasis. In recent years, research on natural FAS inhibitors with significant bioactivities and low side effects has increasingly become a new trend. Herein, we present recent research progress on natural fatty acid synthase inhibitors as potent therapeutic agents. Objective This paper is a mini overview of the typical natural FAS inhibitors and their possible mechanism of action in the past 10 years (2004-2014). Method The information was collected and compiled through major databases including Web of Science, PubMed, and CNKI. Results Many natural products induce cancer cells apoptosis by inhibiting FAS expression, with fewer side effects than synthetic inhibitors. Conclusion Natural FAS inhibitors are widely distributed in plants (especially in herbs and foods). Some natural products (mainly phenolics) possessing potent biological activities and stable structures are available as lead compounds to synthesise promising FAS inhibitors.

  1. Water-enhanced solubility of carboxylic acids in organic solvents and its applications to extraction processes

    SciTech Connect

    Starr, J.N.; King, C.J.

    1991-11-01

    The solubilities of carboxylic acids in certain organic solvents increase remarkably with an increasing amount of water in the organic phase. This phenomenon leads to a novel extract regeneration process in which the co-extracted water is selectively removed from an extract, and the carboxylic acid precipitates. This approach is potentially advantageous compared to other regeneration processes because it removes a minor component of the extract in order to achieve a large recovery of acid from the extract. Carboxylic acids of interest include adipic acid, fumaric acid, and succinic acid because of their low to moderate solubilities in organic solvents. Solvents were screened for an increase in acid solubility with increased water concentration in the organic phase. Most Lewis-base solvents were found to exhibit this increased solubility phenomena. Solvents that have a carbonyl functional group showed a very large increase in acid solubility. 71 refs., 52 figs., 38 tabs.

  2. Morphology of nitric acid and water ice films

    NASA Technical Reports Server (NTRS)

    Keyser, Leon F.; Leu, Ming-Taun

    1993-01-01

    Ice films have been used to simulate stratospheric cloud surfaces in order to obtain laboratory data on solubilities and heterogeneous reaction rates. In the present study, environmental scanning electron microscopy (ESEM) is used to study thin films of both water ice and nitric acid ice near the composition of the trihydrate. The ices are formed by vapor deposition onto aluminum or borosilicate-glass substrates cooled to about 200 K. Micrographs are recorded during the deposition process and during subsequent annealing at higher temperatures. The results show that the ice films are composed of loosely consolidated granules, which range from about 1 to 20 microns in size at temperatures between 197 and 235 K. Cubic water ice is sometimes observed at 200 K, which converts to the hexagonal form at slightly higher temperatures. The loose packing of the granules confirms the high porosities of these films obtained from separate bulk porosity measurements. Average surface areas calculated from the observed granule sizes range from about 0.2 to 1 sq m/g and agree with surface areas obtained by gas-adsorption (BET) analysis of annealed ice films. For unannealed films, the BET areas are about an order of magnitude higher than the ESEM results, implying that the unannealed ices contain microporosity which is lost during the annealing process.

  3. ASSESSING THE ROLE OF NATURAL ATTENUATION FOR INORGANIC CONTAMINANT REMEDIATION IN GROUND WATER

    EPA Science Inventory

    Monitored natural attenuation (MNA) has been applied as a knowledge-based remediation technology for organic contaminants in ground water. The application of this technology is being considered for remediation of inorganic contaminants in ground water at hazardous waste sites. ...

  4. Field and laboratory arsenic speciation methods and their application to natural-water analysis

    USGS Publications Warehouse

    Bednar, A.J.; Garbarino, J.R.; Burkhardt, M.R.; Ranville, J.F.; Wildeman, T.R.

    2004-01-01

    The toxic and carcinogenic properties of inorganic and organic arsenic species make their determination in natural water vitally important. Determination of individual inorganic and organic arsenic species is critical because the toxicology, mobility, and adsorptivity vary substantially. Several methods for the speciation of arsenic in groundwater, surface-water, and acid mine drainage sample matrices using field and laboratory techniques are presented. The methods provide quantitative determination of arsenite [As(III)], arsenate [As(V)], monomethylarsonate (MMA), dimethylarsinate (DMA), and roxarsone in 2-8min at detection limits of less than 1??g arsenic per liter (??g AsL-1). All the methods use anion exchange chromatography to separate the arsenic species and inductively coupled plasma-mass spectrometry as an arsenic-specific detector. Different methods were needed because some sample matrices did not have all arsenic species present or were incompatible with particular high-performance liquid chromatography (HPLC) mobile phases. The bias and variability of the methods were evaluated using total arsenic, As(III), As(V), DMA, and MMA results from more than 100 surface-water, groundwater, and acid mine drainage samples, and reference materials. Concentrations in test samples were as much as 13,000??g AsL-1 for As(III) and 3700??g AsL-1 for As(V). Methylated arsenic species were less than 100??g AsL-1 and were found only in certain surface-water samples, and roxarsone was not detected in any of the water samples tested. The distribution of inorganic arsenic species in the test samples ranged from 0% to 90% As(III). Laboratory-speciation method variability for As(III), As(V), MMA, and DMA in reagent water at 0.5??g AsL-1 was 8-13% (n=7). Field-speciation method variability for As(III) and As(V) at 1??g AsL-1 in reagent water was 3-4% (n=3). ?? 2003 Elsevier Ltd. All rights reserved.

  5. Influence of fulvic acids and copper ions on thiram determination in water.

    PubMed

    Filipe, O M S; Vidal, M M; Duarte, A C; Santos, E B H

    2008-08-27

    The literature concerning the application of solid-phase extraction (SPE) to the concentration of thiram (bis(dimethyldithiocarbamoyl) disulfide) from natural waters is scarce, the available results being contradictory or with no analytical significance. To clarify these contradictory results, a C18-SPE procedure combined with HPLC-UV was applied to thiram analysis in river water, and the influence of several factors on recoveries was studied. This procedure gave thiram recoveries of about 100% when applied to thiram standard solutions. However, when the same procedure was applied to river water samples spiked with thiram, the recoveries depended on the equilibration time after spiking. The influence of river fulvic acids (FAs) and Cu(II) on thiram recoveries from standard solutions was studied as a possible interference for such a result. In the presence of FA, thiram recoveries were always higher than 85%. In the presence of Cu(II), thiram recoveries decreased significantly, due to complexation, but the addition of an excess of EDTA before C18-SPE eliminated that interference, and thiram was completely recovered. However, in river water samples the addition of EDTA had to be done before thiram spiking to obtain a recovery >90%. Thiram standard solutions containing both river FA and Cu(II) showed a behavior similar to the one observed in river water samples. On the basis of these results, the catalytic effect of Cu(II) on the degradation of thiram by FA, with formation of a Cu(II)-dimethyldithiocarbamate complex, was hypothesized.

  6. Evaluation of the potentials of humic acid removal in water by gas phase surface discharge plasma.

    PubMed

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Yan, Qiuhe; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-02-01

    Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process. The mineralization of HA was analyzed by UV-Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment.

  7. Lipophilisation of Caffeic Acid through Esterification with Propanol Using Water-tolerable Acidic Ionic Liquid as Catalyst.

    PubMed

    Liu, Wei; Han, Liya

    2015-01-01

    Propyl caffeate was synthesized to produce lipophilic antioxidant, which used caffeic acid and propanol as starting materials, acidic ionic liquid as catalyst. The highest yield of propyl caffeate (98.7±0.8%) have been achieved under the optimum as follows: 1-butylsulfonic-3-methylimidazolium tosylate showed the best catalytic performance, molar ratio of caffeic acid to propanol was 1:20, reaction temperature was 90°C and the amount of acidic ionic liquid was 40%. The relationship between temperature and the forward rate constant gave the activation energy of 33.6 kJ mol(-1), which indicated that acidic ionic liquid possesses high catalytic activity in the synthesis of PC. And the activity of acidic ionic liquid was not inhibited by the water produced during the esterification process. More importantly, this reaction system can even proceed smoothly when initial water content was 5%.

  8. Acidic deposition: State of science and technology. Report 11. Historical changes in surface-water acid-base chemistry in response to acidic deposition. Final report

    SciTech Connect

    Sullivan, T.J.; Small, M.J.; Kingston, J.C.; Bernert, J.A.; Thomas, D.R.

    1990-09-01

    The objectives of the analyses reported in the State of Science report are to: identify the lake and stream populations in the United States that have experienced chronic changes in biologically significant constituents of surface water chemistry (e.g. pH, Al) in response to acidic deposition; quantify biologically meaningful historical changes in chronic surface water chemistry associated with acidic deposition, with emphasis on ANC, pH, and Al; estimate the proportion of lakes nor acidic that were not acidic in pre-industrial times; estimate the proportional response of each of the major chemical constituents that have changed in response to acidic deposition using a subset of statistically selected Adirondack lakes for which paleolimnological reconstructions of pre-industrial surface water chemistry have been performed; evaluate and improve, where appropriate and feasible, empirical models of predicting changes in ANC; and evaluate the response of seepage lakes to acidic deposition.

  9. Effect of Periodic Water Addition on Citric Acid Production in Solid State Fermentation

    NASA Astrophysics Data System (ADS)

    Utpat, Shraddha S.; Kinnige, Pallavi T.; Dhamole, Pradip B.

    2013-09-01

    Water addition is one of the methods used to control the moisture loss in solid state fermentation (SSF). However, none of the studies report the timing of water addition and amount of water to be added in SSF. Therefore, this work was undertaken with an objective to evaluate the performance of periodic water addition on citric acid production in SSF. Experiments were conducted at different moistures (50-80 %) and temperatures (30-40 °C) to simulate the conditions in a fermenter. Citric acid production by Aspergillus niger (ATCC 9029) using sugarcane baggase was chosen as a model system. Based on the moisture profile, citric acid and sugar data, a strategy was designed for periodic addition of water. Water addition at 48, 96, 144 and 192 h enhanced the citric acid production by 62 % whereas water addition at 72, 120, and 168 h increased the citric acid production by just 17 %.

  10. The nature of carbon dioxide waters in Snaefellsnes, western Iceland

    USGS Publications Warehouse

    Arnorsson, S.; Barnes, I.

    1983-01-01

    Over 20 occurrences of thermal and non-thermal waters rich in carbon dioxide are known in the Snaefellsnes Peninsula of western Iceland. On the basis of the thermal, chemical and isotopic characteristics of these waters, and hydrological considerations, it is concluded that they represent meteoric waters which have seeped to variable depths into the bedrock. Ascending carbon dioxide gas originating from intrusions or the mantle mixes with the meteoric waters to produce carbon dioxide waters: at considerable depth in the case of the thermal carbon dioxide waters but close to the surface in the case of cold carbon dioxide waters. The occurrence of carbon dioxide waters cannot be regarded as evidence for underground geothermal reservoirs. ?? 1983.

  11. Relationship between molecular descriptors and the enthalpies of sublimation of natural amino acids

    NASA Astrophysics Data System (ADS)

    Badelin, V. G.; Tyunina, V. V.; Girichev, G. V.; Tyunina, E. Yu.

    2016-07-01

    A multiparameter correlation between the enthalpies of sublimation and molecular descriptors of natural amino acids is proposed, based on generalized experimental and literature data on the heat effects of sublimation. The contributions from Van der Waals interactions, hydrogen bond formation, and electrostatic effects into enthalpy of sublimation has been evaluated using regression coefficients.

  12. Contributions of acid deposition and natural processes to cation leaching from forest soils: a review

    SciTech Connect

    Johnson, D.W.; Van Miegroet, H.; Cole, D.W.; Richter, D.D.

    1983-01-01

    Methods of quantifying the roles of atmospheric acid inputs and internal acid generation by carbonic, organic, and nitric acids are illustrated by reviewing data sets from several intensively studied sites in North America. Some of the sites (tropical, Costa Rica (La Selva); temperate deciduous, Tennessee (Walker Branch); and temperate coniferous, Washington (Thompson)) received acid precipitation whereas others (northern, southeast Alaska (Petersburg); and subalpine, Washington Cascades (Findley Lake)) did not. Natural leaching by carbonic acid dominated soil leaching in the tropical and temperate coniferous sites, nitric acid (caused by nitrification) dominated leaching in an N-fixing temperate deciduous site (red alder in Washington), and organic acids dominated surface soil leaching in the subalpine site and contributed to leaching of surface soils in several other sites. Only at the temperate deciduous sites in eastern Tennessee did atmospheric acid input play a major role in soil leaching. In no case, however, are the annual net losses of cations regarded as alarming as compared to soil exchangeable cation capital.

  13. Potential beneficial uses of coalbed natural gas (CBNG) water.

    PubMed

    Reddy, K J; Whitman, Ashley J; Kniss, Andrew R

    2014-01-01

    The CBNG well water is typically managed by discharging into nearby disposal ponds. The CBNG well water could potentially be very useful in the water-limited regions (e.g., arid and semi-arid), but beneficial uses may be hindered by water quality problems. Objectives of this research were to: (1) examine trend analysis of nine years of CBNG well water at discharge (outfall) points and in corresponding disposal ponds, (2) evaluate geochemical processes, (3) identify potential water quality issues, and (4) find potential beneficial uses. The CBNG well water at discharge points and in corresponding disposal ponds was measured on-site for pH and electrical conductivity (EC). These water samples were also analyzed in the laboratory for calcium (Ca), sodium (Na), magnesium (Mg), potassium (K), iron (Fe), aluminum (Al), copper (Cu), arsenic (As), selenium (Se), cadmium (Cd), and barium (Ba). Total dissolved solids (TDS) were calculated from EC measurements. The sodium adsorption ratio (SAR) was calculated from Na, Ca, and Mg concentrations. Trend analyses of outfalls and disposal ponds were conducted separately so that the differences in trends could be compared. Trends in CBNG well water at discharge points are not always the same as trends in CBNG disposal ponds: environmental and geochemical processes play an important role in the water quality of these well waters. Overall trend analyses suggest that CBNG well water at discharge points in all basins of the Powder River Basin meets beneficial use criteria, except for SAR and to some extent EC, for aquatic life, livestock and wildlife watering, and irrigation. The CBNG well water in disposal ponds across all basins meets criteria for all beneficial uses except for As, pH, SAR, and to some extent EC for irrigation, aquatic life, and livestock and wildlife watering. PMID:24280972

  14. Structure-thermodynamics-antioxidant activity relationships of selected natural phenolic acids and derivatives: an experimental and theoretical evaluation.

    PubMed

    Chen, Yuzhen; Xiao, Huizhi; Zheng, Jie; Liang, Guizhao

    2015-01-01

    Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media. PMID:25803685

  15. Structure-thermodynamics-antioxidant activity relationships of selected natural phenolic acids and derivatives: an experimental and theoretical evaluation.

    PubMed

    Chen, Yuzhen; Xiao, Huizhi; Zheng, Jie; Liang, Guizhao

    2015-01-01

    Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media.

  16. Evaluation of a chlorous acid-chlorine dioxide teat dip under experimental and natural exposure conditions.

    PubMed

    Drechsler, P A; Wildman, E E; Pankey, J W

    1990-08-01

    A postmilking teat dip containing chlorous acid-chlorine dioxide was evaluated by experimental challenge and in two herds under natural exposure. The test product had an efficacy of 78.9% against Staphylococcus aureus and 52.5% against Streptococcus agalactiae in the experimental challenge trial. The product was compared with a 1% iodine product in a 15-mo natural exposure study. Post-dipping with chlorous acid-chlorine dioxide reduced incidence of udder infection by major mastitis pathogens 36.1% when data were combined from the two herds. The 1% iodine and the chlorous acid-chlorine dioxide products were not equivalent for major mastitis pathogens; the test product was more effective. Incidence of udder infection by environmental mastitis pathogens was reduced 36.8% in both herds combined. Efficacy of the two teat dips was equivalent for environmental pathogens. PMID:2229601

  17. Effects of essential fatty acid deficiency on epidermal O-acylsphingolipids and transepidermal water loss in young pigs.

    PubMed

    Melton, J L; Wertz, P W; Swartzendruber, D C; Downing, D T

    1987-09-25

    Linoleate-rich O-acylglucosylceramides and acylceramides are thought to be of major significance for the physical structure and function of the epidermal permeability barrier. In the present investigation, the effects of a linoleate-free diet on O-acylsphingolipids and their associated functions were investigated. Starting at 5 days of age, male pigs were fed diets containing 12% of either lard or hydrogenated coconut oil. Transepidermal water loss was measured with an electrolytic water analyzer at weekly intervals. Pigs were killed at intervals, and epidermal lipids were isolated and analyzed. Fatty acid compositions were determined by gas-liquid chromatography (GLC). Within 2-3 weeks, pigs on the diet containing coconut oil began to display biochemical and physiological symptoms of essential fatty acid deficiency. Within 2 months, this group had extremely scaly skin and transepidermal water loss was elevated to five times that of controls. The progressive increase in transepidermal water loss correlated with replacement of linoleate by oleate in both acylceramide and acylglucosylceramide. The formation of lamellar granules and intercellular lipid sheets in the stratum corneum was not impaired in essential fatty acid deficiency as judged by electron microscopy. These results suggest that the linoleic acid normally found in the O-acylsphingolipids is not essential for formation of the epidermal membrane system. Rather, it appears that the nature of the ester-linked fatty acid in the O-acylsphingolipids regulates the permeability of this membrane system.

  18. Influence of natural humic acids and synthetic phenolic polymers on fibrinolysis

    NASA Astrophysics Data System (ADS)

    Klöcking, Hans-Peter

    The influence of synthetic and natural phenolic polymers on the release of plasminogen activator was studied in an isolated, perfused, vascular preparation (pig ear). Of the tested synthetic phenolic polymers, the oxidation products of caffeic acid (KOP) and 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), at a concentration of 50 µg/ml perfusate, were able to increase the plasminogen activator activity by 70%. The oxidation products of chlorogenic acid (CHOP), hydrocaffeic acid (HYKOP), pyrogallol (PYROP) and gallic acid (GALOP), at the same concentration, exerted no influence on the release of plasminogen activator. Of the naturally occurring humic acids, the influence of sodium humate was within the same order of magnitude as KOP and 3,4-DHPOP. Ammonium humate was able to increase the plasminogen activator release only at a concentration of 100 µg/ml perfusate. In rats, the t-PA activity increased after i.v. application of 10 mg/kg of KOP, Na-HS or NH4-HS.

  19. Fluoro amino acids: a rarity in nature, yet a prospect for protein engineering.

    PubMed

    Odar, Corinna; Winkler, Margit; Wiltschi, Birgit

    2015-03-01

    Fluoro amino acids are highly valuable compounds constantly gaining relevance in diverse fields of the biosciences as well as in the pharmaceutical industry. The value of these compounds can be attributed to the properties of the extremely electronegative fluorine atom. This atom forms a highly polarized bond of extraordinary strength with carbon. The formation of the fluorine-carbon bond is challenging: its chemical synthesis demands harsh reaction conditions and to date only one class of enzyme has been found capable of introducing the fluoride ion into an organic compound. Most of these fluorinating enzymes participate in the biosynthesis of 4-fluoro-L-threonine, the only fluoro amino acid of natural origin discovered so far. Despite their scarcity in nature, fluoro amino acids are valuable tools to fluorinate proteins. The fluoro protein variants often show improved stability and folding as well as altered activity and fluorescence characteristics. This review details the biosynthesis of 4-fluoro-L-threonine with a special focus on the fluorinating enzymes. Moreover, we elaborate on the application of fluoro amino acids as building blocks for fluorinated protein variants. Insight into different techniques to incorporate fluoro amino acids into proteins is also provided. We highlight prospects and the current relevance of fluoro amino acids as a tool to engineer proteins with novel traits.

  20. Naturally Occurring Arsenic in Ground Water, Norman, Oklahoma, 2004, and Remediation Options for Produced Water

    USGS Publications Warehouse

    Smith, S. Jerrod; Christenson, Scott

    2005-01-01

    can be used to bring some of Norman?s high-arsenic wells into compliance with the new arsenic standard, the EPA Office of Research and Development (ORD) initiated a three-year research project in 2003 with participation from the U.S. Geological Survey (USGS), Oklahoma State University, and the City of Norman. The primary objectives of the project are to: (1) determine where naturally occurring arsenic is entering wells by collecting water samples at different depths, (2) investigate the utility of new methods for collecting water-quality data in a pumping well, (3) better understand the stratigraphy and composition of aquifer rocks, (4) assess 10 wells for the possibility of arsenic remediation by well modification, and (5) evaluate the effectiveness of well modification in bringing marginal wells into compliance with the new arsenic MCL. The purpose of this report is to describe the occurrence of arsenic in ground water near Norman, Oklahoma, and available options for reducing arsenic concentrations in produced ground water.

  1. Acidification sensitivity and critical loads of acid deposition for surface waters in China.

    PubMed

    Ye, Xuemei; Hao, Jiming; Duan, Lei; Zhou, Zhongping

    2002-04-22

    Although decades of severe acid deposition have not resulted in serious surface water acidification in China, at present, the risk of some freshwaters becoming acidified cannot be neglected. To know more clearly about the possible impact acid deposition would have on Chinese surface waters, it is necessary to study the sensitivity of those surface waters to acidification and their critical loads of acid deposition on a national scale. Here we assess the acidification sensitivity of Chinese surface waters using an approach based on geology, soils, land use and hydrological conditions. Critical loads of S, N and acidity were also evaluated by a first-order acidity balance (FAB) model. Results show that most surface waters in China have very high critical loads of S and acidity and are not susceptible to acidification. Surface waters can be divided into three groups according to both sensitivity classes and critical loads. The few most sensitive surface waters are located in the northern part of Daxinganling region, with critical loads of S deposition and acidity lower than 2 keq ha(-1) year(-1). Surface waters in the northeastern region draining dark brown forest soils and in southern China belong to the second class of acidification sensitivity and their critical loads of S and acidity are generally between 2 and 15 keq ha(-1) year(-1), indicating they are not likely to be acidified under any flow conditions. Surface waters in other parts of China will not be acidified to any degree, with critical loads much higher than 15 keq ha(-1) year(-1). The magnitude and spatial distribution pattern of acidification sensitivity have significant similarity to the critical loads of S and acidity for Chinese surface waters. Although most surface waters are not likely to be acidified, attention should still be paid to the possible adverse impact acid deposition would have, especially in northeastern China, where the surface waters are the most sensitive, and the southern region

  2. Temperature dependence of hydrogen-bond dynamics in acetic acid-water solutions.

    PubMed

    D'Amico, Francesco; Bencivenga, Filippo; Gessini, Alessandro; Masciovecchio, Claudio

    2010-08-19

    An inelastic UV scattering experiment has been carried out on acetic acid-water solutions as a function of temperature and concentration. The analysis of experimental data indicates the presence of a crossover temperature (T(c) approximately 325 +/- 10 K). Above T(c), the energy of hydrogen bonds responsible for water-acetic acid and acetic acid-acetic acid interactions is strongly reduced. This leads to a reduction in the average number of water molecule interacting with acetic acid, as well as to a lower number of acetic acid clusters. The latter behavior can be mainly ascribed to a temperature change in the activation energy of carboxylic groups of acetic acid. These results may be also relevant to better understand the folding mechanism in protein-water solutions. PMID:20701390

  3. The features of element concentration in natural waters of the Kola North in conditions of environmental contamination

    NASA Astrophysics Data System (ADS)

    Bazova, Mariya; Moiseenko, Tatyana

    2016-04-01

    The intensive use of fossil fuels and industrial development in last century led to the formation of acid rain and water acidification. The problem of water acidification greatly was denoted in the middle of last century in North America and in Europe as a result of air emissions of acid gases, primarily sulfur dioxide. The process of water acidification due to the interaction of two factors: 1) the high deposition of acidifying substances, taking into account the duration of exposure; 2) the sensitivity of the natural catchment area of geological, landscape, geographic and climatic characteristics (Moiseenko, 2005). The effects of acid rains on metal migration and cycling were discussed in a number of previous studies (Jeffries, 1997; Moiseenko, 1999; Manio, 2001; Moiseenko, Gashkina, 2007). The distribution of elements in water lakes has been mixed and due to the change of geochemical cycles of elements occurring in the catchment area and in water. On the Kola Peninsula as a result of long-term operation of the copper-nickel smelter was the anthropogenic acidification and water pollution metals. Increased contents of elements due to the combined effect of three factors: 1) landscape-geochemical characteristics of watersheds; 2) dispersion with flue emissions; 3) leaching elements and bonding of metals with organic matter, especially in forested watersheds and wetlands. This region is subject to long-term effects of mining and smelting industries, and therefore difficult to find of water bodies, which can serve as a background lakes. It is proved that manmade acid rain lead to leach into the water of a large group of elements entering the water as a result of man-made streams, as well as the elements that consist of the rocks forming the watersheds. In order to identify the relationships between the components of the elemental composition of the water in the lake was made a factor analysis using a computer program «STATISTICA 10". Factor analysis revealed the

  4. Effect of ocean acidification on the fatty acid composition of a natural plankton community

    NASA Astrophysics Data System (ADS)

    Leu, E.; Daase, M.; Schulz, K. G.; Stuhr, A.; Riebesell, U.

    2013-02-01

    The effect of ocean acidification on the fatty acid composition of a natural plankton community in the Arctic was studied in a large-scale mesocosm experiment, carried out in Kongsfjorden (Svalbard, Norway) at 79° N. Nine mesocosms of ~50 m3 each were exposed to 8 different pCO2 levels (from natural background conditions to ~1420 μatm), yielding pH values (on the total scale) from ~8.3 to 7.5. Inorganic nutrients were added on day 13. The phytoplankton development during this 30-day experiment passed three distinct phases: (1) prior to the addition of inorganic nutrients, (2) first bloom after nutrient addition, and (3) second bloom after nutrient addition. The fatty acid composition of the natural plankton community was analysed and showed, in general, high percentages of polyunsaturated fatty acids (PUFAs): 44-60% of total fatty acids. Positive correlations with pCO2 were found for most PUFAs during phases 2 and/or 3, with the exception of 20:5n3 (eicosapentaenoic acid, EPA), an important diatom marker. These correlations are probably linked to changes in taxonomic composition in response to pCO2. While diatoms (together with prasinophytes and haptophytes) increased during phase 3 mainly in the low and intermediate pCO2 treatments, dinoflagellates were favoured by high CO2 concentrations during the same time period. This is reflected in the development of group-specific fatty acid trophic markers. No indications were found for a generally detrimental effect of ocean acidification on the planktonic food quality in terms of essential fatty acids.

  5. Photochemical degradation of sunscreen agent 2-phenylbenzimidazole-5-sulfonic acid in different water matrices.

    PubMed

    Ji, Yuefei; Zhou, Lei; Zhang, Ya; Ferronato, Corinne; Brigante, Marcello; Mailhot, Gilles; Yang, Xi; Chovelon, Jean-Marc

    2013-10-01

    The occurrence of sunscreen agents in natural environment is of scientific concern recently due to their potential risk to ecology system and human beings as endocrine disrupting chemicals (EDCs). In this work the photodegradation mechanism and pathways of sunscreen agent 2-phenylbenzimidazole-5-sulfonic acid (PBSA) were investigated under artificial solar irradiation with the goal of assessing the potential of photolysis as a transformation mechanism in aquatic environments. The quantum yield of PBSA direct photolysis in pH 6.8 buffer solution under filtered mercury lamp irradiation was determined as 2.70 × 10(-4). Laser flash photolysis (LFP) experiments confirmed the involvement of PBSA radical cation (PBSA(·+)) during direct photolysis. Acidic or basic condition facilitated PBSA direct photolysis in aqueous solution. Indirect photolysis out-competes direct photolysis as a major process for PBSA attenuation only at higher level of photosensitizers (e.g., NO3(-) > 2 mM). Thus, direct photolysis is likely to be the major loss pathway responsible for the elimination of PBSA in natural sunlit surface waters, while indirect photolysis (e.g., mediated by HO·) appeared to be less important due to a general low level of steady-state concentration of HO· ([HO·]ss) in natural surface waters. Direct photolysis pathways of PBSA includes desulfonation and benzimidazole ring cleavage, which are probably initiated by the excited triplet state ((3)PBSA*) and radical cation (PBSA(·+)). Conversely, hydroxylation products of PBSA and 2-phenyl-1H-benzimidazole as well as their ring opening intermediates were found in nitrate-induced PBSA photolysis, suggesting the indirect photodegradation was primarily mediated by HO and followed a different mechanism.

  6. Identification of the subsurface sulfide bodies responsible for acidity in Río Tinto source water, Spain

    NASA Astrophysics Data System (ADS)

    Gómez-Ortiz, David; Fernández-Remolar, David C.; Granda, Ángel; Quesada, Cecilio; Granda, Teresa; Prieto-Ballesteros, Olga; Molina, Antonio; Amils, Ricardo

    2014-04-01

    The acidic waters of the Río Tinto rise from several acidic springs that emerge in the area surrounding Peña de Hierro (Fernández-Remolar et al., 2005). These springs are located above minor normal faults that act as natural conduits for the water from the underlying deep aquifer. Although it has been suggested that the acidity of the river originates from the biooxidation of massive and stockwork sulfides (Fernández-Remolar et al., 2008a), the location of the source for these acidic solutions has not previously been established. This lack of evidence has been used to suggest that the acidity of the Río Tinto may be the product of the most conspicuous of the possible source, the extensive mining of the area over approximately the last 5000 years (Davis et al., 2000). In this paper, we report resistivity and time-domain electromagnetic sounding data from the Río Tinto aquifer to a depth of ∼600 m, revealing the locations for the acidic sources. Both types of data support the presence of two distinct geological units that we interpret as thrust sheets emplaced onto each other during the Variscan orogeny of the Carboniferous. These units, both of which contain massive and stockwork sulfides, act as the aquifer for the acidic waters of the Río Tinto. Under this scenario, which is in agreement with the geological record of the Río Tinto fluvial system for the past 6 Ma (Moreno et al., 2003), our results imply that mining activity had little influence on the generation of the acidic river waters.

  7. Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: in vitro experiments

    PubMed Central

    HAKIM, Hakimullah; ALAM, Md. Shahin; SANGSRIRATANAKUL, Natthanan; NAKAJIMA, Katsuhiro; KITAZAWA, Minori; OTA, Mari; TOYOFUKU, Chiharu; YAMADA, Masashi; THAMMAKARN, Chanathip; SHOHAM, Dany; TAKEHARA, Kazuaki

    2016-01-01

    The capacity of slightly acidic hypochlorous acid water (SAHW), in both liquid and spray form, to inactivate bacteria was evaluated as a potential candidate for biosecurity enhancement in poultry production. SAHW (containing 50 or 100 ppm chlorine, pH 6) was able to inactivate Escherichia coli and Salmonella Infantis in liquid to below detectable levels (≤2.6 log10 CFU/ml) within 5 sec of exposure. In addition, SAHW antibacterial capacity was evaluated by spraying it using a nebulizer into a box containing these bacteria, which were present on the surfaces of glass plates and rayon sheets. SAHW was able to inactivate both bacterial species on the glass plates (dry condition) and rayon sheets within 5 min spraying and 5 min contact times, with the exception of 50 ppm SAHW on the rayon sheets. Furthermore, a corrosivity test determined that SAHW does not corrode metallic objects, even at the longest exposure times (83 days). Our findings demonstrate that SAHW is a good candidate for biosecurity enhancement in the poultry industry. Spraying it on the surfaces of objects, eggshells, egg incubators and transport cages could reduce the chances of contamination and disease transmission. These results augment previous findings demonstrating the competence of SAHW as an anti-viral disinfectant. PMID:27052464

  8. Fumaric Acid and Slightly Acidic Electrolyzed Water Inactivate Gram Positive and Gram Negative Foodborne Pathogens

    PubMed Central

    Tango, Charles Nkufi; Mansur, Ahmad Rois; Oh, Deog-Hwan

    2015-01-01

    Sanitizing effectiveness of slightly acidic electrolyzed water (SAEW) and fumaric acid (FA) at different dipping temperatures (25–60 °C), times (1–5 min), and concentrations (5–30 ppm for SAEW and 0.125%–0.5% for FA) on pure cultures of two Gram positive pathogens Staphylococcus aureus (SA) and Listeria monocytogenes (LM) and two Gram negative pathogens Escherichia coli O157:H7 (EC) and Salmonella Typhimurium (ST) was evaluated. FA (0.25%) showed the strongest sanitizing effect, demonstrating complete inactivation of EC, ST, and LM, while SA was reduced by 3.95–5.76 log CFU/mL at 25–60 °C, respectively, after 1 min of treatment. For SAEW, the complete inactivation was obtained when available chlorine concentration was increased to 20 ppm at 40 °C for 3 and 5 min. Moreover, Gram positive pathogens have been shown to resist to all treatment trends more than Gram negative pathogens throughout this experiment. Regardless of the different dipping temperatures, concentrations, and times, FA treatment was more effective than treatment with SAEW for reduction of foodborne pathogens. This study demonstrated that application of FA in food systems may be useful as a method for inactivation of foodborne pathogens.

  9. Fumaric Acid and Slightly Acidic Electrolyzed Water Inactivate Gram Positive and Gram Negative Foodborne Pathogens

    PubMed Central

    Tango, Charles Nkufi; Mansur, Ahmad Rois; Oh, Deog-Hwan

    2015-01-01

    Sanitizing effectiveness of slightly acidic electrolyzed water (SAEW) and fumaric acid (FA) at different dipping temperatures (25–60 °C), times (1–5 min), and concentrations (5–30 ppm for SAEW and 0.125%–0.5% for FA) on pure cultures of two Gram positive pathogens Staphylococcus aureus (SA) and Listeria monocytogenes (LM) and two Gram negative pathogens Escherichia coli O157:H7 (EC) and Salmonella Typhimurium (ST) was evaluated. FA (0.25%) showed the strongest sanitizing effect, demonstrating complete inactivation of EC, ST, and LM, while SA was reduced by 3.95–5.76 log CFU/mL at 25–60 °C, respectively, after 1 min of treatment. For SAEW, the complete inactivation was obtained when available chlorine concentration was increased to 20 ppm at 40 °C for 3 and 5 min. Moreover, Gram positive pathogens have been shown to resist to all treatment trends more than Gram negative pathogens throughout this experiment. Regardless of the different dipping temperatures, concentrations, and times, FA treatment was more effective than treatment with SAEW for reduction of foodborne pathogens. This study demonstrated that application of FA in food systems may be useful as a method for inactivation of foodborne pathogens. PMID:27682077

  10. Fumaric Acid and Slightly Acidic Electrolyzed Water Inactivate Gram Positive and Gram Negative Foodborne Pathogens.

    PubMed

    Tango, Charles Nkufi; Mansur, Ahmad Rois; Oh, Deog-Hwan

    2015-02-12

    Sanitizing effectiveness of slightly acidic electrolyzed water (SAEW) and fumaric acid (FA) at different dipping temperatures (25-60 °C), times (1-5 min), and concentrations (5-30 ppm for SAEW and 0.125%-0.5% for FA) on pure cultures of two Gram positive pathogens Staphylococcus aureus (SA) and Listeria monocytogenes (LM) and two Gram negative pathogens Escherichia coli O157:H7 (EC) and Salmonella Typhimurium (ST) was evaluated. FA (0.25%) showed the strongest sanitizing effect, demonstrating complete inactivation of EC, ST, and LM, while SA was reduced by 3.95-5.76 log CFU/mL at 25-60 °C, respectively, after 1 min of treatment. For SAEW, the complete inactivation was obtained when available chlorine concentration was increased to 20 ppm at 40 °C for 3 and 5 min. Moreover, Gram positive pathogens have been shown to resist to all treatment trends more than Gram negative pathogens throughout this experiment. Regardless of the different dipping temperatures, concentrations, and times, FA treatment was more effective than treatment with SAEW for reduction of foodborne pathogens. This study demonstrated that application of FA in food systems may be useful as a method for inactivation of foodborne pathogens.

  11. Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: in vitro experiments.

    PubMed

    Hakim, Hakimullah; Alam, M