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Sample records for californium nitrates

  1. Metabolism and toxicity of californium

    International Nuclear Information System (INIS)

    Metabolism of californium can be compared with that of other transplutonium elements. The most important points are as follows: a fast blood clearance and fast bone uptake more important than liver uptake, a relatively high urinary excretion and kidney retention. Blood clearance of californium can be compared with that of americium. Distribution of californium 252 nitrate after intramuscular injection in rats was studied. There are very few experimental data on acute or long term toxicity of californium. (28 references)

  2. Magnetism in californium

    International Nuclear Information System (INIS)

    A SQUID-based magnetic susceptometer has been constructed for studying small radioactive samples at temperatures below 350 K and in magnetic fields up to 50 kilogauss. The device has been used to study californium (element 98) in a number of solid-state forms: the dhcp metal, several oxides (Cf2O3 in both the bcc and monoclinic structures, Cf7O12, CfO2 and BaCfO3), several monopnictides (CfN, CfAs and CfSb) and the trichloride (in both the hexagonal and orthorhombic structures). All of these materials were studied in polycrystalline form, and hexagonal CfCl3 was studied in single-crystal form as well. The susceptometer has the sensitivity to measure samples containing less than 10 micrograms of californium. The magnetic susceptibilities of all of the californium materials at temperatures above about 100 K are described well by the Curie-Weiss relationship. This behavior is consistent with the assumption that the magnetic 5f electrons are localized and that the paramagnetic behavior can be interpreted in terms of the properties of the free ion. The measured values of the effective paramagnetic moment, μ/sub eff/, for all the californium materials that were studied are reasonably consistent with theoretical values based on intermediate coupling models. All of the californium materials showed some indications of cooperative magnetic effects. The dhcp metal was observed to order ferromagnetically at 52 K, and all of the californium compounds studied showed signs of antiferromagnetic ordering, mostly at temperatures below 25 K. 91 refs., 50 figs., 19 tabs

  3. Californium Multiplier (CFX)

    International Nuclear Information System (INIS)

    The availability of 252Cf as an economical high-intensity neutron source has made it possible to construct compact neutron irradiation devices with widespread applications. The simplest such device consists of a single 252Cf source within a moderating and shielding medium. Higher neutron flux levels can be attained either through the use of more 252Cf or through source multiplication by means of a subcritical uranium assembly. Although the use of larger 252Cf sources to achieve higher neutron flux is technically straightforward, an economic penalty is paid as the source strength is increased. Larger californium sources imply larger initial investments to cover the cost of source material and larger operating costs resulting from the decay of the 252Cf source. A Californium Multiplier, the CFX, which produces a flux enhancement of 30 when compared to a conventional moderated 252Cf system has been designed, licensed, built, and tested by IRT Corporation. Such systems are now available on a commercial basis for both neutron radiography and neutron activation analysis. The first commercial CFX system was installed at the Research Laboratories of Eastman Kodak Company in Rochester, NY, in March 1975. This device, using 1 mg of 252Cf, is very stable and the neutron flux generated by the CFX is very reproducible. The performance characteristics of this system are summarized

  4. Californium--palladium metal neutron source material

    Science.gov (United States)

    Dahlen, B.L.; Mosly, W.C. Jr.; Smith, P.K.; Albenesius, E.L.

    1974-01-22

    Californium, as metal or oxide, is uniformly dispersed throughout a noble metal matrix, provided in compact, rod or wire form. A solution of californium values is added to palladium metal powder, dried, blended and pressed into a compact having a uni-form distribution of californium. The californium values are decomposed to californium oxide or metal by heating in an inert or reducing atmosphere. Sintering the compact to a high density closes the matrix around the dispersed californium. The sintered compact is then mechanically shaped into an elongated rod or wire form. (4 claims, no drawings) (Official Gazette)

  5. Californium-252 Neutron Sources for Medical Applications

    International Nuclear Information System (INIS)

    Californium-252 neutron sources are being prepared to investigate the value of this radionuclide in diagnosing and treating diseases. A source resembling a cell-loaded radium needle was developed for neutron therapy. Since therapy needles are normally implanted in the body, very conservative design criteria were established to prevent leakage of radioactive. Methods are being developed to prepare very intense californium sources that could be used eventually for neutron radiography and for diagnosis by neutron activation analysis. This paper discusses these methods

  6. Californium Electrodepositions at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Boll, Rose Ann [ORNL

    2015-01-01

    Electrodepositions of californium isotopes were successfully performed at Oak Ridge National Laboratory (ORNL) during the past year involving two different types of deposition solutions, ammonium acetate (NH4C2H3O2) and isobutanol ((CH3)2CHCH2OH). A californium product that was decay enriched in 251Cf was recovered for use in super-heavy element (SHE) research. This neutron-rich isotope, 251Cf, provides target material for SHE research for the potential discovery of heavier isotopes of Z=118. The californium material was recovered from aged 252Cf neutron sources in storage at ORNL. These sources have decayed for over 30 years, thus providing material with a very high 251Cf-to-252Cf ratio. After the source capsules were opened, the californium was purified and then electrodeposited using the isobutanol method onto thin titanium foils for use in an accelerator at the Joint Institute for Nuclear Research in Dubna, Russia. Another deposition method, ammonium acetate, was used to produce a deposition containing 1.7 0.1 Ci of 252Cf onto a stainless steel substrate. This was the largest single electrodeposition of 252Cf ever prepared. The 252Cf material was initially purified using traditional ion exchange media, such as AG50-AHIB and AG50-HCl, and further purified using a TEVA-NH4SCN system to remove any lanthanides, resulting in the recovery of 3.6 0.1 mg of purified 252Cf. The ammonium acetate deposition was run with a current of 1.0 amp, resulting in a 91.5% deposition yield. Purification and handling of the highly radioactive californium material created additional challenges in the production of these sources.

  7. Historical review of californium-252 discovery and development

    International Nuclear Information System (INIS)

    This paper discusses the discovery and history of californium 252. This isotope may be synthesized by irradiating plutonium 239, plutonium 242, americium 243, or curium 244 with neutrons in a nuclear reactor. Various experiments and inventions involving 252Cf conducted at the Savannah River Plant are discussed. The evolution of radiotherapy using californium 252 is reviewed

  8. Californium-252: a remarkable versatile radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Osborne-Lee, I.W.; Alexander, C.W.

    1995-10-10

    A product of the nuclear age, Californium-252 ({sup 252}Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, {sup 252}Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of {sup 252}Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the {sup 252}Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, {sup 252}Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of {sup 252}Cf from ORNL is summarized herein.

  9. Californium-252: a remarkable versatile radioisotope

    International Nuclear Information System (INIS)

    A product of the nuclear age, Californium-252 (252Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, 252Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of 252Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the 252Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, 252Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of 252Cf from ORNL is summarized herein

  10. Californium-252 Neutron Therapy in China

    International Nuclear Information System (INIS)

    Californium-252 brachytherapy, believed to be the most successful source for neutron therapy, gives most of the cures as well as long-term and complication-free survivals. Chinese radiation oncologists were interested in californium neutron therapy (Cf-NT) in the early 1980s, but 252Cf sources for medical use were not available in China until 1992 when a californium joint venture was established by the China Institute of Atomic Energy (Beijing) and the Research Institute for Nuclear Reactors (Dimitrovgrad) of Russia. In 1995, 25 seeds of 252Cf with a strength of 3 μg each were sent to China for preclinical investigation. Three years later, a high dose rate (HDR) 252Cf source was imported and transferred into a home-made remote after-loader for intracavitary treatment in Chongqing, and a clinical trail was started in February 1999. This is the first time that Cf-NT was performed for cancer patients in China. Since then, Cf-NT in China has developed rapidly. It is estimated that one-tenth of those radiation oncology centers with brachytherapy practice will be equipped with californium units in 5 yr. That means more than 30 units will be in use in hospitals. That is significant compared with other countries, but it is just one, on average, for each province or one per 40 million people in China. Progress also has been achieved in the 252Cf treatment delivery equipment. Preliminary clinical trails showed complete response observed in all cases treated, with a rapid clearance of tumors and mild reactions in normal tissues. The short-term results are quite encouraging. To deal with problems due to the demand for Cf-NT in China, attention should be paid to the following particulars: (1) A high-strength miniature source is needed for HDR/MDR interstitial therapy to extend the Cf-NT coverage. (2) Basic work on radiophysics and radiobiology needs to be done, including source calibration, clinical dosimetry, clinical RBE determination, and Cf-NT quality assurance

  11. Californium-252 sales and loans at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    The production and distribution in the United States of 252Cf has recently been consolidated at the Oak Ridge National Laboratory (ORNL). The 252Cf Industrial Sales/Loan Program and the 252Cf University Load Program, which were formerly located at the Savannah River Plant (SRP), have been combined with the californium production and distribution activities of the Transuranium Element Production Program at ORNL. Californium-252 is sold to commercial users in the form of bulk californium oxide, palladium-californium alloy pellets, or alloy wires. Neutron source capsules, which are fabricated for loans to DOE or other US government agencies, are still available in all forms previously available. The consolidation of all 252Cf distribution activities at the production site is expected to result in better service to users. In particular, customers for neutrons sources will be ale to select from a wider range of neutron source forms, including custom designs, through a single contact point

  12. Californium-252 encapsulation at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    More than 1 g of the neutron-emitting isotope californium-252 has been encapsulated at SRL for worldwide medical, industrial, and research uses. Bulk sales packages have been prepared for the USDOE sales program since 1971. Doubly-encapsulated sources have been prepared for USDOE's market evaluation program since 1968. Californium-252 sources for loan and sales packages satisfy the criteria for Special Form Radioactive Material. Encapsulation is performed in special neutron-shielded containment facilities at SRL. Development of improved source and shipping package designs and processes is continuing. 17 figures

  13. Production, distribution and applications of californium-252 neutron sources

    International Nuclear Information System (INIS)

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 1011 neutrons s-1. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations

  14. Production, distribution and applications of californium-252 neutron sources.

    Science.gov (United States)

    Martin, R C; Knauer, J B; Balo, P A

    2000-01-01

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 10(11) neutrons s(-1). Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordinance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations. PMID:11003521

  15. Production, Distribution, and Applications of Californium-252 Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Balo, P.A.; Knauer, J.B.; Martin, R.C.

    1999-10-03

    The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-year half-life. A source the size of a person's little finger can emit up to 10{sup 11} neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6- year half-life. A source the size of a person's little finger can emit up to 10 neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory(ORNL). DOE sells {sup 252}Cf to commercial

  16. Production of extra pure curium and californium preparations

    International Nuclear Information System (INIS)

    Preparations of curium-244,245,248 and californium-249,252 are used for the production of ionizing radiation sources for different applications and fundamental nuclear-physical investigations, placing high requirements on the radiochemical and chemical purity of the preparations. Extraction chromatography using di-(2-ethylhexyl)phosphoric acid (D2EHPA) as extractant was chosen to prepare extra pure curium and californium preparations. In order to identify the optimal conditions of Cm-Cf separation and to remove impurities from them (reagent and other impurities), investigations were performed into the effect of impurities (Na+, Ca2+, Al3+, Fe2+, Fe3+ taken as example), extractant and eluent concentration and solution flow rate on the efficiency of mutual purification of Cm and Cf. Both theoretical and experimental estimations were made of the maximum concentration at which the impurities do not affect the process. The conditions chosen allow mutual purification of milligram amounts of Cm and Cf from impurity elements at E(pur) =102 - 103 during a single chromatographic cycle (E(pur) =>103) using a column with 5 - 10 cm3 volume. In this case the production yield exceeds 98%. The purification of milligram amounts of curium and californium from fission products (lanthanides in general, cerium in particular) was performed in D2EHPA-decane-PbO2-HNO3 and D2EHPA-decane-DTPA-H3-Cit extraction chromatography systems. In order to establish the optimal conditions, the effect of [D2EHPA] and eluent on the mutual purification of Cm and Cf and on their purification from cerium and impurity elements was studied in the D2EHPA-decane-PbO2-HNO3 system. During a single chromatographic cycle the mutual purification factors of TPE and of their purification from impurity cations achieve 102-103, from cerium - E(pur) > 10. In the D2EHPA-decane-DTPA-H3Cit system, the effect of concentration of extractant and eluent pH on the efficiency of Cm and Cf purification from lanthanides was

  17. Prompt neutron spectrum of the spontaneous fission of californium-252

    International Nuclear Information System (INIS)

    The californium-252 spontaneous fission neutron spectrum was measured in the energy range of 0.01 to 10 MeV by the time-of-flight technique using various neutron detectors. The measurements of 252Cf neutron spectrum at energies of 0.01 to 5 MeV were performed as a function of fission fragment kinetic energy. The mean neutron spectrum energy in the range of 0.7 to 10 MeV was found from the results of measurements. The irregularity in the 252Cf neutron spectrum in the neutron energy range of less than 0.7 MeV compared to theoretical values is discussed. The mechanism of 252Cf neutron emission is also discussed on the basis of neutron yield angle measurements. 12 references

  18. Separation of californium from actinides and lanthanides in aqueous solution by electrochemical formation of amalgams

    International Nuclear Information System (INIS)

    The electrochemical reduction of transneptunium elements (Pu to Cf) and rare earths (Eu, Tm) from aqueous complexing solutions to amalgams was studied over a wide range of cathodic potentials in order to achieve optimal separation of californium. The reduction in acetate media (pH 4.5-4.6) at potentials around -1.7 to -1.9 V1 leads to a quantitative extraction of californium into the mercury phase, while more negative potentials are required for the reduction of the lighter transuranium elements and of the lanthanides. Hence, the optimal conditions for the separation of californium from the investigated actinides and lanthanides were determined. Separation factors α between 25 and 90 were found except in the case of Cf/Eu, where poor values (α varying from 7 to 12) were observed. More negative cathodic potentials decrease the selectivity of the reduction process. A similar study with lithium citrate solutions (pH ∝6) shows that satisfactory separation of californium from lighter and heavier actinides is achievable. A separation factor of 88 is obtained for Cf/Am at -1.98 V. The anodic stripping of mixed amalgams (Pu, Am, Cm, Bk, Tm and Cf) Hg in nitric and acetic acid soultions at potentials ranging from +0.1 to -0.7 V proceeds slowly and proved to be ineffective for the separation of californium from light actinides under conditions described. (orig.)

  19. On-line slurry analyses by californium-252

    International Nuclear Information System (INIS)

    In chemical processing technology on-line activation methods gain an increasing importance for process monitoring and control. A method is described according to which the different fluorspar contents at various strategic points of a flotation plant are determined through neutron activation by 100 μg californium-252. A continuous analytical system for onstream process control of slurries was designed and constructed. A compact facility, called SUSAC, allows continuous application of the method on an industrial scale. The main components of the SUSAC facility are the irradiation and measurement cells. The cells are equipped with multistage countercurrent stirrers ensuring a proper radial and vertical distribution of the sample. The hollow shaft of the stirrer of the irradiation cell houses the Cf-source. The NaI-detector has been installed in a recess in the bottom of the measuring cell. The volumes are 9 dm3 for the irradiation cell, 7.5 dm3 for the measuring cell, 1/2 dm3 for the vonnection line and 4 dm3 for feed and drainage lines including the pump. Investigations on the following topics are discussed: selection of stirrers, residence time, flow rate, pulp density, calibration measurements. (T.G.)

  20. Biomedical neutron research at the Californium User Facility for neutron science

    International Nuclear Information System (INIS)

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact 252Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with 252Cf sources. Three projects at the CUF that demonstrate the versatility of 252Cf for biological and biomedical neutron-based research are described: future establishment of a 252Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded 252Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy

  1. Biomedical neutron research at the Californium User Facility for neutron science

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.C. [Oak Ridge National Lab., TN (United States); Byrne, T.E. [Roane State Community College, Harriman, TN (United States); Miller, L.F. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-04-01

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact {sup 252}Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with {sup 252}Cf sources. Three projects at the CUF that demonstrate the versatility of {sup 252}Cf for biological and biomedical neutron-based research are described: future establishment of a {sup 252}Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded {sup 252}Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy.

  2. Proposed Californium-252 User Facility for Neutron Science at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    The Radiochemical Engineering Development Center (REDC) at ORNL has petitioned to establish a Californium-252 User Facility for Neutron Science for academic, industrial, and governmental researchers. The REDC Californium Facility (CF) stores the national inventory of sealed 252Cf neutron source for university and research loans. Within the CF, the 252Cf storage pool and two uncontaminated hot cells currently in service for the Californium Program will form the physical basis for the User Facility. Relevant applications include dosimetry and experiments for neutron tumor therapy; fast and thermal neutron activation analysis of materials; experimental configurations for prompt gamma neutron activation analysis; neutron shielding and material damage studies; and hardness testing of radiation detectors, cameras, and electronics. A formal User Facility simplifies working arrangements and agreements between US DOE facilities, academia, and commercial interests

  3. Emergence of californium as the second transitional element in the actinide series.

    Science.gov (United States)

    Cary, Samantha K; Vasiliu, Monica; Baumbach, Ryan E; Stritzinger, Jared T; Green, Thomas D; Diefenbach, Kariem; Cross, Justin N; Knappenberger, Kenneth L; Liu, Guokui; Silver, Mark A; DePrince, A Eugene; Polinski, Matthew J; Van Cleve, Shelley M; House, Jane H; Kikugawa, Naoki; Gallagher, Andrew; Arico, Alexandra A; Dixon, David A; Albrecht-Schmitt, Thomas E

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, and show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. The metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence. PMID:25880116

  4. Fissile analysis of Hanford waste using Californium Multiplier/Delayed Neutron Counter system

    International Nuclear Information System (INIS)

    Measurement of low-level (10 ng/g or lower) fissile material (mainly plutonium) in Hanford waste and process samples is becoming increasingly important. A system has been designed consisting of a Californium Multiplier (CFX) and a Delayed Neutron Counter (DNC) to characterize these samples. This report describes hardware and analytical capability of the CFX/DNC system

  5. Study of the shielding for spontaneous fission sources of Californium-252

    International Nuclear Information System (INIS)

    A shielding study is made to attenuate, until maximum permissible levels, the neutrons radiation and photons emitted by spontaneous fission coming from a source of Californium-252. The compound package by a database (Library DLC-23) and the ANISNW code is used, in it version for personal computer. (Author)

  6. Californium (252Cf) and its use as neutron source in science medicine and technology

    International Nuclear Information System (INIS)

    The application of radionuclides in science and nuclear techniques basically is related to unstable isotopes, which are produced from stable elements in nuclear reactor. Their specifications are various from view point of application . Using of physical and chemical properties of radionuclides in chemistry, for with marking the organic compounds we can exactly explain the mechanism of chemical reactions in medical, biology and bio-chemistry. In these cases the behaviour of radionuclides is very important and the selection of the suitable radionuclides is determined between the elements for investigation aims. The special specification of radio-nuclides analysis such as, half-life, kind of ray and energy should be considered with an special accuracy as well as the laws security regulations from view point of ray-protection should be completely observed mean time working these radio-nuclides. It should be considered that application of radio-isotopes is very important from their special specifications point of view. Applying the radionuclides from technology point of view in sciences and nuclear techniques aren't only limited to three analyses of α, β, and γ, but we can use the share of neutron which are produced from spli ting of heavy nucleus such as Californium252 as a neutron source in the depths of the sea and also determining the concentration of low quantity elements on moon and other spheres. The radioisotope of Californium252 is a neutron useful radiator for investigation in nuclear medical and technology because of automatically rapid split to 3.2% Californium252 radiates 1.34 * 109N/m in each mil/GH which suitable replacement for neutron sources based on (a, n) reaction, for example, Radium-Brellium or Amersium-Brellium. The energy distribution of radiated neutrons from analyzing of Californium252 like the spectrum of neutron which is produced from splitting of U235, Pu239 nucleus has the maximum energy in quantity, En=1 MeV in the range of 1.5 MeV. The

  7. Contribution to clinical dosimetry of californium 252 sources used at Gustave Roussy institute

    International Nuclear Information System (INIS)

    The main characteristics of californium 252 sources are presented in the first part of the report. Dose measurements around Californium sources were performed with a pair of ionization multiplication chambers: the first one has an Aluminium wall and is filled with Argon, the second one a plastic tissue-equivalent gas. A set of experiments was performed in order to investigate the relative influence of beta rays on the response of both chambers. Besides the experimental work a computer program was written to calculate the dose distribution around the actual sources made of a series of small active sources placed in catheters. Theoretical data around small sources can be found in the litterature. The comparison between experimental results and theoretical ones has shown a good agreement. The computer program will be included as a sub-routine in the more general computer program used for patients treated with interstitial therapy

  8. Safety Analysis Report for Packaging (SARP) of the Oak Ridge National Laboratory TRU Californium Shipping Container

    International Nuclear Information System (INIS)

    An analytical evaluation of the Oak Ridge National Laboratory TRU Californium Shipping Container was made in order to demonstrate its compliance with the regulations governing off-site shipment of packages that contain radioactive material. The evaluation encompassed five primary categories: structural integrity, thermal resistance, radiation shielding, nuclear criticality safety, and quality assurance. The results of this evaluation demonstrate that the container complies with the applicable regulations

  9. Emergence of californium as the second transitional element in the actinide series

    OpenAIRE

    Cary, Samantha K.; Vasiliu, Monica; Baumbach, Ryan E.; Stritzinger, Jared T.; GREEN, THOMAS D.; Diefenbach, Kariem; Cross, Justin N.; Knappenberger, Kenneth L.; Liu, Guokui; Silver, Mark A.; DePrince, A. Eugene; Polinski, Matthew J.; Van Cleve, Shelley M.; House, Jane H.; Kikugawa, Naoki

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resu...

  10. Measurements of integral cross sections in the californium-252 fission neutron spectrum

    International Nuclear Information System (INIS)

    In a low-scattering arrangement cross sections averaged over the californium-252 spontaneous fission neutron spectrum were measured. The reactions 27Al(n,α)46Ti, 47Ti, 48Ti(n,p), 54Fe,56Fe(n,p), 58Ni(n,p), 64Zn(n,p), 115In(n,n') were studied in order to obtain a consistent set of threshold detectors used in fast neutron flux density measurements. Overall uncertainties between 2 and 2.5% could be achieved; corrections due to neutron scattering in source and samples are discussed

  11. Measurement of californium-252 gamma photons depth dose distribution in tissue equivalent material. Vol. 4

    International Nuclear Information System (INIS)

    Phantom of tissue equivalent material with and without bone was used measuring depth dose distribution of gamma-rays from californium-252 source. The source was positioned at center of perspex walled phantom. Depth dose measurements were recorded for X, Y and Z planes at different distances from source. TLD 700 was used for measuring the dose distribution. Results indicate that implantation of bone in tissue equivalent medium cause changes in the gamma depth dose distribution which varies according to variation in bone geometry. 9 figs

  12. Spontaneous Partitioning of Californium from Curium: Curious Cases from the Crystallization of Curium Coordination Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cary, Samantha K.; Silver, Mark A.; Liu, Guokui; Wang, Jamie C.; Bogart, Justin A.; Stritzinger, Jared T.; Arico, Alexandra A.; Hanson, Kenneth; Schelter, Eric J.; Albrecht-Schmitt, Thomas E.

    2015-12-07

    The reaction of 248CmCl3 with excess 2,6-pyridinedicarboxylic acid (DPA) under mild solvothermal conditions results in crystallization of the tris-chelate complex Cm(HDPA)3·H2O. Approximately half of the curium remains in solution at the end of this process, and evaporation of the mother liquor results in crystallization of the bis-chelate complex [Cm(HDPA)- (H2DPA)(H2O)2Cl]Cl·2H2O. 248Cm is the daughter of the α decay of 252Cf and is extracted in high purity from this parent. However, trace amounts of 249,250,251Cf are still present in all samples of 248Cm. During the crystallization of Cm(HDPA)3·H2O and [Cm(HDPA)(H2DPA)(H2O)2Cl]Cl·2H2O, californium(III) spontaneously separates itself from the curium complexes and is found doped within crystals of DPA in the form of Cf(HDPA)3. These results add to the growing body of evidence that the chemistry of californium is fundamentally different from that of earlier actinides.

  13. Paliperidonium nitrate

    Directory of Open Access Journals (Sweden)

    Jingshui Ge

    2012-10-01

    Full Text Available In the title molecular salt (systematic name: 3-{2-[4-(6-fluoro-1,2-benzoxazol-3-ylpiperidin-1-yl]ethyl}-9-hydroxy-2-methyl-1,6,7,8,9,9a-hexahydropyrido[1,2-a]pyrimidin-4-one nitrate, C23H29FN4O3+·NO3−, the piperidine ring displays a chair conformation and its N atom is protonated; the N—H bond is in an axial orientation. The ring bearing the hydroxy group exhibits a half-chair conformation. The hydroxy group as well as the adjacent methylene group are disordered over two sets of sites in a 0.823 (5:0.177 (5 ratio. In the crystal, O—H...N, O—H...O, N—H...O and N—H...N hydrogen bonds connect the components into a three-dimensional network.

  14. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ostroumov, P. N., E-mail: ostroumov@anl.gov; Barcikowski, A.; Dickerson, C. A.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G. P. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Pikin, A. I. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2015-08-15

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz.

  15. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

    International Nuclear Information System (INIS)

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz

  16. Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252

    International Nuclear Information System (INIS)

    Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U233 when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO2(NO3)4 and 18% of thorium Th(NO3)4 as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 107 s-1. In the design the value of the effective multiplication factor, whose value turned out keff <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

  17. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source.

    Science.gov (United States)

    Ostroumov, P N; Barcikowski, A; Dickerson, C A; Perry, A; Pikin, A I; Sharamentov, S I; Vondrasek, R C; Zinkann, G P

    2015-08-01

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz. PMID:26329185

  18. Neutron activation analysis at the Californium User Facility for Neutron Science

    International Nuclear Information System (INIS)

    The Californium User Facility (CUF) for Neutron Science has been established to provide 252Cf-based neutron irradiation services and research capabilities including neutron activation analysis (NAA). A major advantage of the CUF is its accessibility and controlled experimental conditions compared with those of a reactor environment The CUF maintains the world's largest inventory of compact 252Cf neutron sources. Neutron source intensities of ≤ 1011 neutrons/s are available for irradiations within a contamination-free hot cell, capable of providing thermal and fast neutron fluxes exceeding 108 cm-2 s-1 at the sample. Total flux of ≥109 cm-2 s-1 is feasible for large-volume irradiation rabbits within the 252Cf storage pool. Neutron and gamma transport calculations have been performed using the Monte Carlo transport code MCNP to estimate irradiation fluxes available for sample activation within the hot cell and storage pool and to design and optimize a prompt gamma NAA (PGNAA) configuration for large sample volumes. Confirmatory NAA irradiations have been performed within the pool. Gamma spectroscopy capabilities including PGNAA are being established within the CUF for sample analysis

  19. Long-term effects of an intracavitary treatment with californium-252 on normal tissue

    International Nuclear Information System (INIS)

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with 252Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from 252Cf and 7000 rad from 226Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for 252Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from 252Cf and 5000 rad from 226Ra

  20. Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source

    International Nuclear Information System (INIS)

    Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction 55Mn (n.gamma)56 Mn, high concentration of manganese in the matrix and short half - life of 56Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions 56Fe(n,p)56Mn and 59 Co (n, α)56 were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

  1. Five-year cure of cervical cancer treated using californium-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    Female pelvic carcinoma is one of the common malignancies seen at the University of Kentucky Medical Center and often presents in an advanced stage. In 1976, the authors began to test californium-252 neutron brachytherapy (NT) for its efficacy for control of primary and recurrent advanced uterine, cervix, and vaginal cancers. The first protocol used was 5000-5500 rad of whole pelvis irradiation followed by 1-2 Cf-252 insertions using a single tandem placed in the utero-cervico-vaginal region. Of 27 patients with primary carcinomas treated, 10 are alive and well 5 year later (37%). Two of two recurrent tumors were locally controlled but failed later. These patients had advanced cervical, vaginal, or endometrial carcinomas. In 1977, a transitional year, treatment of only unfavorable stages and presentations with NT was initiated. Similar results were obtained with NT as compared to conventional photon therapy (PT). Further improvement in treatment results can be anticipated as NT brachytherapy is used for advanced cancer therapy by more effective treatment schedules and radiation doses. Cf-252 can be used as a radium substitute and achieved similar rates of tumor control and 5-year survivals. 21 references, 2 tables

  2. Uptake and distribution of californium-252 chloride administered intraperitoneally, intravenously or intratracheally and the effect of in vivo DTPA chelation on intratracheal instillation in the rat

    International Nuclear Information System (INIS)

    The first phase of this investigation, comprising of three groups of animals, was designed to study the fate of californium-252 chloride administered intraperitoneally, intravenously or intratracheally. The second phase, which consisted of two groups of animals, was designed to examine the effectiveness of DTPA chelation therapy in accelerating the excretion and preventing the deposition of californium-252 chloride instilled into the lungs of rats. Immediately following the dose administration of 2 uCi of californium-252 chloride which was dissolved in 0.2 ml of 0.9% NaCl at pH 3.5, each rat was placed in a metabolism cage. Each rat in the first group of phase II was given intraperitoneal injection of CaNa3 DTPA (50 mg/kg) and each rat in the second group was given intraperitoneal injections of 0.9% NaCl. Injections of the DTPA or the NaCl sham were initiated immediately after the intratracheal administration of californium-252 chloride and were continued every three days until sacrifice. Following intraperitoneal, intravenous or intratracheal administration, the whole body retention of californium as a function of time was described by a three component exponential equation. For each mode of administration the short term component exhibited a biological half-life of between 5 and 10 hours; the intermediate component between 4 and 6 days; and the long term component between 200 and 300 days. The organ data obtained following intraperitoneal and intravenous administration were indistinguishable. On day one, the liver retained about 9% of the administered dose and the kidneys retained 2.4%. Retention for these organs decreased to about 1% by day 32. The femurs maintained an almost constant level of 4.5% of the injected dose over the 32 days. The lungs, spleen, heart, and testes showed significant retention of californium

  3. ENEA results in the international comparison organized by BIPM for the measurament of neutron fluxes of a Californium source

    International Nuclear Information System (INIS)

    During the period between May 1978 and August 1984 under the auspices of Section III of CCEMRI of CIPM it has been carried out the international intercomparison of Californium neutron source emission rate. The previous intercomparison was based on Ra-Be (α -n) source measuraments, which took place between 1959 and 1965, and the results showed a total spread of +- 3%. Owing to the better accuracy achived over the following decade the Ra-Be intercomparison was no longer representative of the state of the art, therefore it was decided to arrange the intercomparison based on Californium which in the meantime reached a wide use in the world. Contributions to the intercomparison were received from fourteen laboratories representative of twelve Nations plus the BIPM. The results put into evidence a considerable advance on accuracy in the neutron source emission rate measuraments. The standard deviation of the residuals obtained from least square fit of normalized data resulted +- 0,57%. In the present report it is widely described the Manganese bath method used at ENEA, CRE Casaccia in Roma, and the experimental procedure followed for its absolute calibration. All measuraments are reported and analysed, including those effectuated for corrective factors determination. The final results obtained at ENEA for the circulated Californium source is (3,457 +- 0,013) 10*H7 neutron/s. The analysis of data from all partecipantes has been effectuated and concluded by J. Axton in March 1986 and the conclusions which have been showed in the present report put in evidence the satisfactory results achived by the ENEA

  4. Feasibility and market potential of protein determination of wheat using californium-252

    International Nuclear Information System (INIS)

    To evaluate the feasibility of protein determination by capture gamma-ray analysis using californium-252 neutrons, an in-situ protein analysis system for use by grain handlers has been examined. Three 227 kilogram (approximately) lots of wheat were used to determine the amount of nitrogen present. Protein analyses by the Kjeldahl method were obtained from samples taken before and after the capture gamma-ray analyses. The 5.267-MeV gamma-ray was selected for use in this study as a compromise between efficiency and interference from other elements. The associated counting equipment was a multichannel analyzer with pulse shaping electronic and analysis computing equipment. A linear regression program was used to compare the regions of interest to the Kjeldahl protein averages. The counts composing each peak were summed and normalized using the total count of the hydrogen peak. The normalized nitrogen percentages indicate a significant correlation between the spectral regions and the Kjeldahl analyses. To a first approximation, the value of wheat is the wheat protein. At the present time, protein testing of wheat is destructive, cumbersome, and time-consuming as compared to the potential for capture gamma-ray analysis testing. Assuming that such a protein analysis unit can analyze 42 tonne of wheat per hour, over 120 units would be needed to monitor one-half the U.S. annual wheat production. A 0.5% improvement in processor realizations and grain throughput value of $167.00 per tonne will result in a projected savings of $150,000 per year per unit

  5. Oxygen enhancement ratio (OER) and therapeutic gain factor (GF) for californium-252 at low dose rate

    International Nuclear Information System (INIS)

    The potential benefit of the introduction of californium-252 in interstitial and intracavitary therapy is related to the greater efficiency of its neutron emission against anoxic cancer cells. In that respect, the oxygen enhancement ratio (OER) of the 252Cf emission has been determined for a continuous low dose rate irradiation. The biological system is growth inhibition in Vicia faba bean roots. A new Vicia faba ''BelB'' strain has been used, which better tolerates long periods (up to about 10 hours) of anoxia. In a first series of experiments, for a 252Cf (Dsub(n+γ)) dose rate of 0.11 Gy.h-1, an OER of 1.4+-0.1 was observed (the γ contribution Dγ to the total absorbed dose Dsub(n+γ) was 0.35 at the position of the root tips). In a second series of experiments, in somewhat different geometrical conditions with a 252Cf (Dsub(n+γ)) dose rate of 0.13 Gy.h-1, an OER of 1.5+-0.1 was observed (Dγ/Dsub(n+γ)=0.42). The OER values observed for similar irradiation times, with iridium-192 γ-rays, were 2.3+-0.2 and 2.6+-0.1 respectively, which leads to therapeutic gain factors (GF) of 1.6 and 1.7 respectively. These GF values are slightly lower than those previously obtained (GF=1.8) on the same system, with d(50)-Be p(75)-Be and 15 MeV neutron beams

  6. Application of TSH bioindicator for studying the biological efficiency of neutrons from californium-252 source

    International Nuclear Information System (INIS)

    The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (TSH-assay) was studied. The special attention was paid to check whether any enhancement in effects caused by process of boron neutron capture is visible in the cells enriched with boron ions. Two chemicals (borax and BSH) were applied to introduce boron-10 ions into cells. Inflorescence, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a Cf-252 source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) in the induction of gene mutations of the neutron beam under the study, Tradescantia inflorescences, without any chemical pretreatment, were irradiated with various doses of X-rays. The ranges of radiation doses used were 0-0.1 Gy in neutrons and 0-0.5 Gy in X-rays. After the time needed to complete the postirradiation repair Tradescantia cuttings were transferred to Cracow, where screening of gene and lethal; mutations, cell cycle alterations in somatic cells have been done, and dose response relationships were figured. The maximal RBE values were estimated in the range of 4.6-6.8. Alterations of RBE value were observed; from 6.8 to 7.8 in the case of plants pretreated with 240 ppm of B-10 from borax, and 4.6 to 6.1 in the case of 400 ppm of B-10 from BSH. Results showed a slight, although statistically insignificant increase in biological efficacy of radiation from the Cf-252 source in samples pretreated with boron containing chemicals. (author)

  7. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  8. Nitrate accumulation in spinach

    NARCIS (Netherlands)

    Steingröver, Eveliene Geertruda

    1986-01-01

    Leafy vegetables, like spinach, may contain high concentrations of nitrate. In the Netherlands, about 75% of mean daily intake of nitrate orginates from the consumption of vegatables. Hazards to human health are associated with the reduction of nitrate to nitrite. Acute nitrite poisoning causes meth

  9. Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii).

    Science.gov (United States)

    Dau, Phuong D; Shuh, David K; Sturzbecher-Hoehne, Manuel; Abergel, Rebecca J; Gibson, John K

    2016-08-01

    The divalent oxidation state is increasingly stable relative to the trivalent state for the later actinide elements, with californium the first actinide to exhibit divalent chemistry under moderate conditions. Although there is evidence for divalent Cf in solution and solid compounds, there are no reports of discrete complexes in which Cf(II) is coordinated by anionic ligands. Described here is the divalent Cf methanesulfinate coordination complex, Cf(II)(CH3SO2)3(-), prepared in the gas phase by reductive elimination of CH3SO2 from Cf(III)(CH3SO2)4(-). Comparison with synthesis of the corresponding Sm and Cm complexes reveals reduction of Cf(III) and Sm(III), and no evidence for reduction of Cm(III). This reflects the comparative 3+/2+ reduction potentials: Cf(3+) (-1.60 V) ≈ Sm(3+) (-1.55 V) ≫ Cm(3+) (-3.7 V). Association of O2 to the divalent complexes is attributed to formation of superoxides, with recovery of the trivalent oxidation state. The new gas-phase chemistry of californium, now the heaviest element to have been studied in this manner, provides evidence for Cf(II) coordination complexes and similar chemistry of Cf and Sm. PMID:27424652

  10. Hypoxic versus normoxic external-beam irradiation of cervical carcinoma combined with californium-252 neutron brachytherapy. Comparative treatment results of a 5-year randomized study

    Czech Academy of Sciences Publication Activity Database

    Tačev, T.; Vacek, Antonín; Ptáčková, B.; Strnad, V.

    2005-01-01

    Roč. 181, č. 5 (2005), s. 273-284. ISSN 0179-7158 Institutional research plan: CEZ:AV0Z50040507 Keywords : cervical carcinoma * hypoxyradiotherapy * californium-252 Subject RIV: BO - Biophysics Impact factor: 3.490, year: 2005

  11. Nitrate pollution of groundwater

    International Nuclear Information System (INIS)

    Concern about the possible health risks associated with the consumption of nitrate has led many countries, including South Africa, to propose that 10mg of nitrogen (as nitrate or nitrite) per liter should be the maximum allowable limit for domestic water supplies. Groundwater in certain parts of South Africa and Namibia contains nitrate in concentrations which exceed this limit. The CSIR's Natural Isotope Division has been studying the nitrogen isotope composition of the nitrate as an aid to investigation into the sources of this nitrate contamination

  12. Solving the Hydration Structure of the Heaviest Actinide Aqua Ion Known: The Californium(III) Case

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, Ch.; Guillaumont, D. [CEA Marcoule, Nucl Energy Div, Radiochem Proc Dept, SCPS LILA, 30 (France); Galbis, E.; Pappalardo, Rafael R.; Marcos Sanchez, E. [Univ Seville, Dept Quim Fis, E-41012 Seville (Spain); Hernandez-Cobos, J. [Inst Ciencias Fis, Cuernavaca 62251, Morelos (Mexico); Le Naour, C.; Simoni, E. [Univ Paris Sud, Inst Phys Nucl Orsay, Paris (France)

    2010-07-01

    In summary, the first MC simulation of the trivalent cation of californium, based on an exchangeable hydrated ion-water intermolecular potential, has been shown to extend and improve the hydrated ion model. Likewise, the CfL{sub III}-edge EXAFS spectrum of an acidic 1 mm Cf(ClO{sub 4}){sub 3} aqueous solution recorded under optimized experimental conditions has greatly improved the signal/noise ratio of the only previously recorded spectrum. The comparison of the experimental EXAFS spectrum with the two computed ones, obtained from two different intermolecular potentials that predict eight (BP86) or nine (MP2) water molecules in the first coordination shell, leads to the conclusion that the lowest hydration number is preferred. Then, as Cf{sup III} is the heaviest actinide aqua ion for which there is experimental information, the actinide contraction is supported by the present study. (For U{sup III}, R{sub U-O}=2.56 Angstroms, and CN=9{+-}1; for Pu{sup III}, R{sub Pu-O}=2.51 Angstroms and CN=9{+-}1; for Cm{sup III}, R{sub Cm-O}=2.47 Angstroms and CN=9{+-}1). The role of the second hydration shell is important in defining the structure and dynamics of the Cf{sup III} aqua ion, but the contribution of second-shell water molecules to the EXAFS signal as back-scatters is marginal. Finally, this work gives an illustrative example of the benefits which can be achieved from the combination of experimental X-ray absorption spectroscopy and computer simulations. The usefulness of the simultaneous analysis of the results as well as the importance of the structural statistical average has been clearly demonstrated herein. Each technique independently was not adequate. We believe that this study traces out a still poorly explored combined methodology which may be extremely useful for many other complexes and chemical problems. A systematic theoretical and experimental examination of the other known actinide cations on the same basis should be undertaken to confirm the

  13. Field determination of nitrate using nitrate reductase

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, E.R.; Corrigan, J.S.; Campbell, W.H. [Nitrate Elimination Co., Inc., Lake Linden, MI (United States)

    1997-12-31

    Nitrate is routinely measured in a variety of substrates - water, tissues, soils, and foods - both in the field and in laboratory settings. The most commonly used nitrate test methods involve the reduction of nitrate to nitrite via a copper-cadmium reagent, followed by reaction of the nitrite with the Griess dye reagents. The resulting color is translated into a nitrate concentration by comparison with a calibrated color chart or comparator, or by reading the absorbance in a spectrophotometer. This basic method is reliable and sufficiently sensitive for many applications. However, the cadmium reagent is quite toxic. The trend today is for continued increase in concern for worker health and safety; in addition, there are increasing costs and logistical problems associated with regulatory constraints on transport and disposal of hazardous materials. Some suppliers have substituted a zinc-based reagent powder for the cadmium in an effort to reduce toxicity. We describe here an enzyme-based nitrate detection method as an improvement on the basic Griess method that demonstrates equal or superior sensitivity, superior selectivity, and is more environmentally benign. Comparisons between the enzyme-based method and some standard field test kits being used today are made.

  14. Design, construction, and characterization of a facility for neutron capture gamma ray analysis of sulfur in coal using californium-252

    International Nuclear Information System (INIS)

    A study of neutron capture gamma ray analysis of sulfur in coal using californium-252 as a neutron source is reported. Both internal and external target geometries are investigated. The facility designed for and used in this study is described. The external target geometry is found to be inappropriate because of the low thermal neutron flux at the sample location, which must be outside the biological shielding. The internal target geometry is found to have a sufficient thermal neutron flux, but an excessive gamma ray background. A water filled plastic facility, rather than the paraffin filled steel one used in this study, is suggested as a means of increasing flexibility and decreasing the beackground in the internal target geometry

  15. Agricultural nitrate pollution

    DEFF Research Database (Denmark)

    Anker, Helle Tegner

    2015-01-01

    Despite the passing of almost 25 years since the adoption of the EU Nitrates Directive, agricultural nitrate pollution remains a major concern in most EU Member States. This is also the case in Denmark, although a fairly strict regulatory regime has resulted in almost a 50 per cent reduction...

  16. Thermochemical nitrate reduction

    International Nuclear Information System (INIS)

    A series of preliminary experiments was conducted directed at thermochemically converting nitrate to nitrogen and water. Nitrates are a major constituent of the waste stored in the underground tanks on the Hanford Site, and the characteristics and effects of nitrate compounds on stabilization techniques must be considered before permanent disposal operations begin. For the thermochemical reduction experiments, six reducing agents (ammonia, formate, urea, glucose, methane, and hydrogen) were mixed separately with ∼3 wt% NO3- solutions in a buffered aqueous solution at high pH (13); ammonia and formate were also mixed at low pH (4). Reactions were conducted in an aqueous solution in a batch reactor at temperatures of 200 degrees C to 350 degrees C and pressures of 600 to 2800 psig. Both gas and liquid samples were analyzed. The specific components analyzed were nitrate, nitrite, nitrous oxide, nitrogen, and ammonia. Results of experimental runs showed the following order of nitrate reduction of the six reducing agents in basic solution: formate > glucose > urea > hydrogen > ammonia ∼ methane. Airnmonia was more effective under acidic conditions than basic conditions. Formate was also effective under acidic conditions. A more thorough, fundamental study appears warranted to provide additional data on the mechanism of nitrate reduction. Furthermore, an expanded data base and engineering feasibility study could be used to evaluate conversion conditions for promising reducing agents in more detail and identify new reducing agents with improved performance characteristics

  17. Operational experience with the Argonne National Laboratory Californium Rare Ion Breeder Upgrade facility and electron cyclotron resonance charge breeder

    Science.gov (United States)

    Vondrasek, R.; Clark, J.; Levand, A.; Palchan, T.; Pardo, R.; Savard, G.; Scott, R.

    2014-02-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory Argonne Tandem Linac Accelerator System (ATLAS) facility provides low-energy and accelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. A 350 mCi 252Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The ECR charge breeder has achieved stable beam charge breeding efficiencies of 10.1% for 23Na7+, 17.9% for 39K10+, 15.6% for 84Kr17+, and 12.4% for 133Cs27+. For the radioactive beams, a charge breeding efficiency of 11.7% has been achieved for 143Cs27+ and 14.7% for 143Ba27+. The typical breeding times are 10 ms/charge state, but the source can be tuned such that this value increases to 100 ms/charge state with the best breeding efficiency corresponding to the longest breeding times—the variation of efficiencies with breeding time will be discussed. Efforts have been made to characterize and reduce the background contaminants present in the ion beam through judicious choice of q/m combinations. Methods of background reduction are being investigated based upon plasma chamber cleaning and vacuum practices.

  18. Long-term effects of an intracavitary treatment with californium-252 on normal tissue. [Swine, /sup 226/Ra

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, M.F.; Beamer, J.L.; Mahony, T.D.; Cross, F.T.; Lund, J.E.; Endres, G.W.R.

    1976-01-01

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with /sup 252/Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from /sup 252/Cf and 7000 rad from /sup 226/Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for /sup 252/Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from /sup 252/Cf and 5000 rad from /sup 226/Ra.

  19. Results with the electron cyclotron resonance charge breeder for the 252Cf fission source project (Californium Rare Ion Breeder Upgrade) at Argonne Tandem Linac Accelerator System

    International Nuclear Information System (INIS)

    The construction of the Californium Rare Ion Breeder Upgrade, a new radioactive beam facility for the Argonne Tandem Linac Accelerator System (ATLAS), is nearing completion. The facility will use fission fragments from a 1 Ci 252Cf source; thermalized and collected into a low-energy particle beam by a helium gas catcher. In order to reaccelerate these beams, an existing ATLAS electron cyclotron resonance (ECR) ion source was redesigned to function as an ECR charge breeder. Thus far, the charge breeder has been tested with stable beams of rubidium and cesium achieving charge breeding efficiencies of 9.7% into 85Rb17+ and 2.9% into 133Cs20+.

  20. Nitrates and nitrites intoxications’ management

    OpenAIRE

    Alexandra Trif

    2007-01-01

    The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers), circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride), factors that determine high nitrates accumulation in fodders despite optimal fertilizati...

  1. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Science.gov (United States)

    2010-07-01

    ..., described and defined as an oxidizer by the regulations of 49 CFR part 173 is handled, stored, stowed...) must be eliminated or plugged. Note: See 49 CFR 176.415 for permit requirements for nitro carbo nitrate... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section...

  2. Nitrate in drinking water

    DEFF Research Database (Denmark)

    Schullehner, Jörg; Hansen, Birgitte; Sigsgaard, Torben

    Annual nationwide exposure maps for nitrate in drinking water in Denmark from the 1970s until today will be presented based on the findings in Schullehner & Hansen (2014) and additional work on addressing the issue of private well users and estimating missing data. Drinking water supply in Denmark...... is highly decentralized and fully relying on simple treated groundwater. At the same time, Denmark has an intensive agriculture, making groundwater resources prone to nitrate pollution. Drinking water quality data covering the entire country for over 35 years are registered in the public database Jupiter....... In order to create annual maps of drinking water quality, these data had to be linked to 2,852 water supply areas, which were for the first time digitized, collected in one dataset and connected to the Jupiter database. Analyses of the drinking water quality maps showed that public water supplies...

  3. Nitrates and nitrites intoxications’ management

    Directory of Open Access Journals (Sweden)

    Alexandra Trif

    2007-12-01

    Full Text Available The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers, circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride, factors that determine high nitrates accumulation in fodders despite optimal fertilization (factors related to the plants, soil, clime, harvest methods, storage, agrotechnical measures, nitrates/nitrites toxicity (over 45 ppm nitrates in drinking water, over 0.5 g nitrate/100 g D.M fodder/diet, the factors that influence nitrates/nitrites toxicity ( species, age, rate of feeding, diet balance especially energetically, pathological effects and symptoms (irritation and congestions on digestive tract, resulting diarrhoea, transformation of hemoglobin into methemoglobin determining severe respiratory insufficiency, vascular collapse, low blood pressure inthe acute nitrates intoxication; hypotiroidism, hypovitaminosis A, reproductive disturbances(abortion, low rate of fertility, dead born offspring, diarrhoea and/or respiratory insufficiency in new born e.g. calves, immunosuppression, decrease of milk production in chronic intoxication. There were presented some suggestions concerning management practices to limit nitrate intoxication (analyze of nitrates/nitrites in water and fodders, good management of the situation of risk ,e .g. dilution of the diet with low nitrate content fodders, feeding with balanced diet in energy, protein, minerals and vitamins, accommodation to high nitrate level diet, avoid grazing one week after a frost period, avoid feeding chop green fodders stored a couple of days, monitoring of health status of animals fed with fodders containing nitrates at risk level, a.o..

  4. Ab initio full-potential study of mechanical properties and magnetic phase stability of californium monopnictides (CfN and CfP)

    Science.gov (United States)

    Amari, S.; Bouhafs, B.

    2016-09-01

    Based on the first-principles methods, the structural, elastic, electronic, properties and magnetic ordering of californium monopnictides CfX (X = P) have been studied using the full-potential augmented plane wave plus local orbitals (FP-L/APW + lo) method within the framework of density functional theory (DFT). The electronic exchange correlation energy is described by generalized gradient approximation GGA and GGA+U (U is the Hubbard correction). The GGA+U method is applied to the rare-earth 5f states. We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii. The elastic properties of the studied compounds are only investigated in the most stable calculated phase. In order to gain further information, we have calculated Young's modulus, shear modulus, anisotropy factor and Kleinman parameter by the aid of the calculated elastic constants. The results mainly show that californium monopnictides CfX (X = P) have an antiferromagnetic spin ordering. Density of states (DOS) and charge densities for both compounds are also computed in the NaCl (B1) structure.

  5. Nitrate biosensors and biological methods for nitrate determination.

    Science.gov (United States)

    Sohail, Manzar; Adeloju, Samuel B

    2016-06-01

    The inorganic nitrate (NO3‾) anion is present under a variety of both natural and artificial environmental conditions. Nitrate is ubiquitous within the environment, food, industrial and physiological systems and is mostly present as hydrated anion of a corresponding dissolved salt. Due to the significant environmental and toxicological effects of nitrate, its determination and monitoring in environmental and industrial waters are often necessary. A wide range of analytical techniques are available for nitrate determination in various sample matrices. This review discusses biosensors available for nitrate determination using the enzyme nitrate reductase (NaR). We conclude that nitrate determination using biosensors is an excellent non-toxic alternative to all other available analytical methods. Over the last fifteen years biosensing technology for nitrate analysis has progressed very well, however, there is a need to expedite the development of nitrate biosensors as a suitable alternative to non-enzymatic techniques through the use of different polymers, nanostructures, mediators and strategies to overcome oxygen interference. PMID:27130094

  6. Nitrate storage and dissimilatory nitrate reduction by eukaryotic microbes

    DEFF Research Database (Denmark)

    Kamp, Anja; Høgslund, Signe; Risgaard-Petersen, Nils; Stief, Peter

    2015-01-01

    storage and dissimilatory nitrate reduction by diverse marine eukaryotes placed into an eco-physiological context. The advantage of intracellular nitrate storage for anaerobic energy conservation in oxygen-depleted habitats is explained and the life style enabled by this metabolic trait is described. A...

  7. [1-(Carboxymethylcyclohexyl]methanaminium nitrate

    Directory of Open Access Journals (Sweden)

    Elise J. C. de Vries

    2011-02-01

    Full Text Available The title compound, C9H18NO2+·NO3−, is an anhydrous nitrate salt of gabapentin, which is formed serendipitously in the presence of selected non-coordinating metals. The crystal structure involves extensive hydrogen bonding between the –NH3+ and –COOH groups and the nitrate anion.

  8. Evaluation of nitrate destruction methods

    International Nuclear Information System (INIS)

    A wide variety of high nitrate-concentration aqueous mixed [radioactive and Resource Conservation and Recovery Act (RCRA) hazardous] wastes are stored at various US Department of Energy (DOE) facilities. These wastes will ultimately be solidified for final disposal, although the waste acceptance criteria for the final waste form is still being determined. Because the nitrates in the wastes will normally increase the volume or reduce the integrity of all of the waste forms under consideration for final disposal, nitrate destruction before solidification of the waste will generally be beneficial. This report describes and evaluates various technologies that could be used to destroy the nitrates in the stored wastes. This work was funded by the Department of Energy's Office of Technology Development, through the Chemical/Physical Technology Support Group of the Mixed Waste Integrated Program. All the nitrate destruction technologies will require further development work before a facility could be designed and built to treat the majority of the stored wastes. Several of the technologies have particularly attractive features: the nitrate to ammonia and ceramic (NAC) process produces an insoluble waste form with a significant volume reduction, electrochemical reduction destroys nitrates without any chemical addition, and the hydrothermal process can simultaneously treat nitrates and organics in both acidic and alkaline wastes. These three technologies have been tested using lab-scale equipment and surrogate solutions. At their current state of development, it is not possible to predict which process will be the most beneficial for a particular waste stream

  9. Waterproofing Materials for Ammonium Nitrate

    Directory of Open Access Journals (Sweden)

    R.S. Damse

    2004-10-01

    Full Text Available This study explores the possibility of overcoming the problem of hygroscopicity of ammonium nitrate by coating the particles with selected waterproofing materials. Gravimetric analysis ofthe samples of ammonium nitrate coated with eight different waterproofing materials, vis-a-vis, uncoated ammonium nitrate, were conducted at different relative humidity and exposuretime. The results indicate that mineral jelly is the promising waterproofing material for ammonium nitrate among the materials tested, viz, calcium stearate, dioctyl phthalate, kaoline, diethylphthalate, dinitrotoluene, shelac varnish, and beeswax. Attempts were made to confirm the waterproofing ability of mineral jelly to ammonium nitrate using differential thermal analysisand x-ray diffraction patterns as an experimental tool. Suitability of mineral jelly as an additive for the gun propellant was also assessed on the basis of theoretical calculations using THERMprogram.

  10. Anatomy of a controversy: Application of the Langevin technique to the analysis of the Californium-252 Source-Driven Noise Analysis method for subcriticality determination

    International Nuclear Information System (INIS)

    The expressions for the power spectral density of the noise equivalent sources have been calculated explicitly for the (a) stochastic transport equation, (b) the one-speed transport equaton, (c) the one-speed P1 equations, (d) the one-speed diffusion equation and (e) the point kinetic equation. The stochastic nature of Fick's law in (d) has been emphasized. The Langevin technique has been applied at various levels of approximation to the interpretation of the Californium-252 Source-Driven Noise Analysis (CSDNA) experiment for determining the reactivity in subcritical media. The origin of the controversy surrounding this method has been explained. The foundations of the CSDNA method as a viable experimental technique to infer subcriticality from a measured ratio of power spectral densities of the outputs of two neutron detectors and a third external source detector has been examined by solving the one-speed stochastic diffusion equation for a point external Californium-252 source and two detectors in an infinite medium. The expression relating reactivity to the measured ratio of PSDs was found to depend implicitly on k itself. Through a numerical analysis fo this expression, the authors have demonstrated that for a colinear detector-source-detector configuration for neutron detectors far from the source, the expression for the subcritical multiplication factor becomes essentially insensitive to k, hence, demonstrating some possibility for the viability of this technique. However, under more realistic experimental conditions, i.e., for finite systems in which diffusion theroy is not applicable, the measurement of the subcritical multiplication factor from a single measured ratio of PSDs, without extensive transport calculations, remains doubtful

  11. Application of SCGE assay, classical cytogenetics and FISH for studying in vitro californium-252 neutrons irradiations and BSH pretreatment on human lymphocytes

    International Nuclear Information System (INIS)

    Recently, there has been observed a tendency to apply various energy neutrons for tumor therapy and particularly low energy neutrons from various sources, including californium-252 source, for cancer radiotherapy based on the neutron capture. In this study peripheral blood lymphocytes were used as a model for human cells and three methods were applied to assess the effectiveness of californium-252 neutrons irradiations in vitro in normal cells or pre-treated with compound enriched in B-10 ion. Human blood samples or isolated lymphocytes were irradiated with neutrons from isotopic 252Cf source at the Faculty of Nuclear Physics and Technics at University of Mining and Metallurgy (both neutron source and samples were placed in polyethylene block). Chemical pretreatment with BSH (Na210B12H11SH) was done to introduce boron-10 ion into cells in order to check any enhancement effect due to the process of boron neutron capture. Comet assay was done to investigate the DNA damage. Classical cytogenetics was applied to assess the frequencies of unstable aberrations (dicentrics and rings). Fluorescence in situ hybridization (FISH) with probes for chromosomes 1, 4 (14.3% of whole genome) and pancentromeric probe was performed to evaluate the frequencies of stable aberrations. Linear (or close to linear) increase of DNA damage and aberration frequency was observed with dose of radiation both for lymphocytes untreated or pre-treated with BSH. Very little differences (statistically insignificant) due to radiation dose and BSH pretreatment were observed in the frequencies of SCEs detected in the second mitosis. There is no significant difference between boron pre-treated and not treated cells, and even slightly higher effects were observed in case of the highest dose without BSH pretreatment. The level of translocations observed is comparable with the frequencies of dicentrics and rings. (author)

  12. Excess nitrate loads to coastal waters reduces nitrate removal efficiency

    DEFF Research Database (Denmark)

    Lunau, Mirko; Voss, Maren; Erickson, Matthew;

    2013-01-01

    Terrestrial ecosystems are becoming increasingly nitrogen-saturated due to anthropogenic activities, such as agricultural loading with artificial fertilizer. Thus, more and more reactive nitrogen is entering streams and rivers, primarily as nitrate, where it is eventually transported towards the ...

  13. Californium-252 neutron sources

    International Nuclear Information System (INIS)

    Major production programs for the Savannah River reactors and the High Flux Isotopes Reactor at Oak Ridge have made 252Cf one of the most available and, at the USAEC's sales price of $10/μg, one of the least-expensive isotopic neutron sources. Reactor production has totaled approximately 2 g, and, based on expected demand, an additional 10 g will be produced in the next decade. The approximately 800 mg chemically separated to date has been used to prepare over 600 neutron sources. Most, about 500, have been medical sources containing 1 to 5 μg of 252Cf plated in needles for experimental cancer therapy studies. The remainder have generally been point sources containing 10 μg to 12 mg of oxide for activation, well logging, or radiography uses. Bulk sources have also been supplied to the commercial encapsulators. The latest development has been the production of 252Cf cermet wire which can be cut into almost contamination-free lengths of the desired 252Cf content. Casks are available for transport of sources up to 50 mg. Subcritical assemblies have been developed to multiply the source neutrons by a factor of 10 to 40, and collimators and thermalizers have also been extensively developed to shape the neutron flux and energy distributions for special applications. (U.S.)

  14. Extraction of lanthanide (3) nitrates by trialkylmethylammonium nitrate in decane

    International Nuclear Information System (INIS)

    Extraction of lanthanide (3) nitrates (praseodymium (3) - lutetium (3)) by trialkylmethylammonium nitrate in decane at T=298.15 K and pH2 is studied. The extraction isotherms are described with an account of formation of compounds of the (R4N)i(Ln(NO3)3+i) composition. Extraction constants values, which become reduced in the praseodymium (3)-lutetium (3) series, are calculated

  15. Rare earth(3) nitrates extraction with trialkylmethylammonium nitrate in toluene

    International Nuclear Information System (INIS)

    Extraction of rare earth(3) nitrates [praseodymium(3)-lutetium(3)] with trialkylmethylammonium nitrate in toluene at T = 298.15 K and pH 2 is studied. Extraction isotherms are described with regard to formation of compounds of (R4N)i[Ln(NO3)3+i] composition (i = 2, 3) in organic phase. Values of extraction constants are calculated, they are decreasing in the praseodymium(3) - lutetium(3) series

  16. Scandium extraction by methyltrialkylammonium nitrate from nitrate solutions

    International Nuclear Information System (INIS)

    Chemistry of scandium extraction by methyltrialkylammonium (MTAA) nitrate in toluene from nitrate solutions is studied. Methods of saturation, equilibrium shift, physicochemical analysis, isomolar series and UV-spectroscopy are used to determine the composition of extracted complexes. It is shown that with low saturation degrees of extractant (R4N)6Sc(NO3)9 complex is formed in organic phase and with saturation - (R4N)3xSc(NO3)6 complex

  17. Calculations of Nuclear Astrophysics and Californium Fission Neutron Spectrum Averaged Cross Section Uncertainties Using ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0 and Low-fidelity Covariances

    International Nuclear Information System (INIS)

    Nuclear astrophysics and californium fission neutron spectrum averaged cross sections and their uncertainties for ENDF materials have been calculated. Absolute values were deduced with Maxwellian and Mannhart spectra, while uncertainties are based on ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0 and Low-Fidelity covariances. These quantities are compared with available data, independent benchmarks, EXFOR library, and analyzed for a wide range of cases. Recommendations for neutron cross section covariances are given and implications are discussed

  18. Biological denitrification of nitrate wastes

    International Nuclear Information System (INIS)

    Enriched uranium wastes are purified in the Y-12 Plant, and the uranium product is recycled. One purification method involves dissolving the waste in nitric acid followed by solvent extraction to recover uranium. The process generates nitrate waste solutions which must be discarded. For many years, these wastes were stored in unlined ponds. In 1976 a recycle process was installed, and about half of the wastes were recovered and reused. A biological process (stirred tank) was installed, and the remaining nitrate wastes were biologically decomposed to produce nitrogen gas. Some additional nitrate wastes, generated in other parts of the plant, continued to be placed in the open ponds which must now be decommissioned. In 1983 an in-situ biological process was developed and tested whereby the open ponds were successfully biologically treated. This paper describes the results of the stirred tank and the in-situ pond treatment processes used in the plant to decompose nitrate ions

  19. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    OpenAIRE

    F. Paulot; Ginoux, P.; Cooke, W. F.; L. J. Donner; S. Fan; Lin, M; J. Mao; Naik, V.; Horowitz, L.W.

    2015-01-01

    We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric model (AM3). Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting th...

  20. Modelling crop root development and nitrate uptake

    OpenAIRE

    Pedersen, Anders

    2008-01-01

    Nitrate leaching from agricultural areas is a political and environmental issue at both local scale in Denmark and at global scale. Plant-available nitrogen and nitrate in the rooting zone in the growing season is necessary in order to obtain satisfactory crop yields. However, surplus nitrogen leads to a risk of nitrate losses through leaching and denitrification. In addition to artificial applications of nitrate, nitrate is produced by mineralisation processes in the soil from plant residues...

  1. Catalyzed reduction of nitrate in aqueous solutions

    International Nuclear Information System (INIS)

    Sodium nitrate and other nitrate salts in wastes is a major source of difficulty for permanent disposal. Reduction of nitrate using aluminum metal has been demonstrated, but NH3, hydrazine, or organic compounds containing oxygen would be advantageous for reduction of nitrate in sodium nitrate solutions. Objective of this seed money study was to determine minimum conditions for reduction. Proposed procedure was batchwise heating of aqueous solutions in closed vessels with monitoring of temperatures and pressures. A simple, convenient apparatus and procedure were demonstrated for observing formation of gaseous products and collecting samples for analyses. The test conditions were 250 degree C and 1000 psi max. Any useful reduction of sodium nitrate to sodium hydroxide as the primary product was not found. The nitrate present at pHs 3 or NH4NO3 is easily decomposed, and the effect of nitromethane at these low pHs was confirmed. When acetic acid or formic acid was added, 21 to 56% of the nitrate in sodium nitrate solutions was reduced by methanol or formaldehyde. With hydrazine and acetic acid, 73 % of the nitrate was decomposed to convert NaNO3 to sodium acetate. With hydrazine and formic acid, 36% of the nitrate was decomposed. If these products are more acceptable for final disposal than sodium nitrate, the reagents are cheap and the conversion conditions would be practical for easy use. Ammonium acetate or formate salts did not significantly reduce nitrate in sodium nitrate solutions

  2. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel-Design concept and experimental demonstration

    Science.gov (United States)

    Henzlova, D.; Menlove, H. O.; Rael, C. D.; Trellue, H. R.; Tobin, S. J.; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

    2016-01-01

    This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be orientation in the instrument.

  3. A biological source of oceanic alkyl nitrates

    Science.gov (United States)

    Dahl, E. E.; Lewis, C. B.; Velasco, F. L.; Escobar, C.; Kellogg, D.; Velcamp, M.

    2013-12-01

    Alkyl nitrates are an important component of reactive nitrogen in the troposphere. The oceans are a source of alkyl nitrates to the atmosphere, however the source of alkyl nitrates in the oceans is unknown. It has been demonstrated that the reaction of alkyl peroxy radicals (ROO) with nitric oxide (NO) produces alkyl nitrates in the aqueous phase. We hypothesize that alkyl nitrates may be formed by organisms through the same reaction and therefore biological production could be a source of alkyl nitrates to the troposphere. This work focuses on the production of alkyl nitrates by the diatoms Chaetoceros muelleri and Thalassiosira weisfloggi. Using chemostats, we measure alkyl nitrates formed under nitrate limited conditions. We also use triggers and inhibitors of nitric oxide formation to determine if alkyl nitrate formation is affected by changes in NO production. To date, the rates of production of alkyl nitrates in our cultures, lead us to estimate a production rate on the order of femtomolar/day for C1-C3 alkyl nitrates by diatom species in the equatorial Pacific Ocean. This suggests that diatoms may contribute to the overall ocean source of alkyl nitrates; however, it is possible that other types of phytoplankton, such as cyanobacteria, that are more abundant in the open ocean, may contribute to a greater extent.

  4. Nitrate metabolism in the gromiid microbial universe

    DEFF Research Database (Denmark)

    Høgslund, Signe; Risgaard-Petersen, Nils; Cedhagen, Tomas

    Eukaryotic nitrate respiration supported by intracellular nitrate storages contributes substantially to the nitrogen cycle. Research focus is currently directed towards two phyla: Foraminifera and diatoms, but the widespread Gromia in the Rhizaria may be another key organism. These giant protists...

  5. Metal nitrate conversion method, patent application

    NARCIS (Netherlands)

    2008-01-01

    A method for converting a supported metal nitrate into the corresponding supported metal comprises heating the metal nitrate to effect its decomposition under a gas mixture that contains nitric oxide and has an oxygen content of

  6. A Novel Chemical Nitrate Destruction Process

    Energy Technology Data Exchange (ETDEWEB)

    Dziewinski, J.; Marczak, S.

    1999-03-01

    Nitrates represent one of the most significant pollutant discharged to the Baltic Sea by the Sliiamae hydrometallurgical plant. This article contains a brief overview of the existing nitrate destruction technologies followed by the description of a new process developed by the authors. The new chemical process for nitrate destruction is cost effective and simple to operate. It converts the nitrate to nitrogen gas which goes to the atmosphere.

  7. Modeling nitrate removal in a denitrification bed

    Science.gov (United States)

    Denitrification beds are being promoted to reduce nitrate concentrations in agricultural drainage water to alleviate the adverse environmental effects associated with nitrate pollution in surface water. In this system, water flows through a trench filled with a carbon media where nitrate is transfor...

  8. 21 CFR 172.160 - Potassium nitrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium nitrate. 172.160 Section 172.160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a...

  9. Nitrate Uptake, Nitrate Reductase Distribution and their Relation to Proton Release in Five Nodulated Grain Legumes

    OpenAIRE

    Fan, X. H.; Tang, C; RENGEL, Z.

    2002-01-01

    Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0·2 and 2 mm nitrate in nutrient solution. Nitrate treatments, imposed on 22‐d‐old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0·2 mm nitrate supply, nitrate uptake rates ran...

  10. High temperature interaction studies on equimolar nitrate mixture of uranyl nitrate hexahydrate and gadolinium nitrate hexahydrate

    International Nuclear Information System (INIS)

    Rare earths including gadolinium form a sizeable fraction of the fission products in the nuclear fission of fissile material in the reactor. These fission products can interact with uranium dioxide fuel and can form various compounds which can alter the thermal behavior of the fuel. The mixed oxide formed due to the high temperature interactions of mixture of uranyl nitrate hexahydrate (UNH) and gadolinium nitrate hexahydrate (GdNH) has been studied using thermal and X- ray diffraction techniques. The equimolar mixture of UNH and GdNH was prepared by mixing the weighed amount of individual nitrates and grinding gently with mortar and pestle. Thermogravimetry (TG) measurements were carried out by separately heating 100 mg of mixture and individual nitrates at heating rate of 10°C min-1 using Netzsch thermal analyzer (Model No.: STA 409 PC Luxx) in high purity nitrogen atmosphere with a flow rate of 120 mL min-1. The XRD measurement was carried out on a Philips X-ray diffractometer (Model PW1710) using nickel-filtered Cu-Kα radiation

  11. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration*

    OpenAIRE

    Olah, George A.; Narang, Subhash C.; Olah, Judith A.

    1981-01-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an α-nitronaphthalene to β-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aroma...

  12. Deconstructing nitrate isotope dynamics in aquifers

    Science.gov (United States)

    Granger, J.

    2012-12-01

    The natural abundance N and O stable isotope ratios of nitrate provide an invaluable tool to differentiate N sources to the environment, track their dispersal, and monitor their attenuation by biological transformations. The interpretation of patterns in isotope abundances relies on knowledge of the isotope ratios of the source end-members, as well as on constraints on the isotope discrimination imposed on nitrate by respective biological processes. Emergent observations from mono-culture experiments of denitrifying bacteria reveal nitrate fractionation trends that appear at odds with trends ascribed to denitrification in soils and aquifers. This discrepancy raises the possibility that additional biological N transformations may be acting in tandem with denitrification. Here, the N and O isotope enrichments associated with nitrate removal by denitrification in aquifers are posited to bear evidence of coincident biological nitrate production - from nitrification and/or from anammox. Simulations are presented from a simple time-dependent one-box model of a groundwater mass ageing that is subject to net nitrate loss by denitrification with coincident nitrate production by nitrification or anammox. Within boundary conditions characteristic of freshwater aquifers, the apparent slope of the parallel enrichments in nitrate N and O isotopes associated with net N loss to denitrification can vary in proportion to the nitrate added simultaneous by oxidative processes. Pertinent observations from nitrate plumes in suboxic to anoxic aquifers are examined to validate this premise. In this perspective, nitrate isotope distributions suggest that we may be missing important N fluxes inherent to most aquifers.

  13. Phase diagram of ammonium nitrate

    International Nuclear Information System (INIS)

    Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

  14. Collection of Nitrate in a Denuder

    Directory of Open Access Journals (Sweden)

    Hannah Feig

    2008-01-01

    Full Text Available Data are given for aerosol nitrate (NO3- size distributions in the atmosphere as recorded by a cascade impactor and by an annular denuder. Using this data, our goal is to find the percent of nitrate in the atmosphere that the denuder is able to detect. This requires that we find the size distribution of nitrate that enters the denuder. From these data and calculations, we find that 32.8% of nitrate in the atmosphere can be detected by the denuder. Nitrate was measured to study its affects on seagrass in the Tampa Bay and to compare nitrate levels with seagrass growth and decline. Using a denuder for routine measurements will not allow scientists to accurately compare nitrate data to seagrass levels.

  15. 5-Chloro-8-hydroxyquinolinium nitrate

    Directory of Open Access Journals (Sweden)

    Seik Weng Ng

    2009-06-01

    Full Text Available The 5-chloro-8-hydroxyquinolinium cation in the the title ion pair, C9H7ClNO+·NO3−, is approximately coplanar with the nitrate anion [dihedral angle = 16.1 (1°]. Two ion pairs are hydrogen bonded (2 × O—H...O and 2 × N—H...O about a center of inversion, generating an R44(14 ring.

  16. 2-Amino-5-chloropyridinium nitrate

    Directory of Open Access Journals (Sweden)

    Donia Zaouali Zgolli

    2009-11-01

    Full Text Available The title structure, C5H6ClN2+·NO3−, is held together by extensive hydrogen bonding between the NO3− ions and 2-amino-5-chloropyridinium H atoms. The cation–anion N—H...O hydrogen bonds link the ions into a zigzag- chain which develops parallel to the b axis. The structure may be compared with that of the related 2-amino-5-cyanopyridinium nitrate.

  17. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Science.gov (United States)

    2010-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  18. Biological Efficiency of Californium-252 Source Evaluated by Comet Assay, Classical Cytogenetics and FISH in Human Lymphocytes Irradiated without and with BSH Pretreatment

    International Nuclear Information System (INIS)

    Biological effectiveness of californium-252 source was evaluated after irradiations in vitro of normal or pre-treated with compound enriched in B-10 ion cells. Peripheral blood lymphocytes were used as a model for human cells. DNA and chromosomal damage were studied to compare biological effectiveness of irradiation. Human blood samples or isolated lymphocytes were irradiated with the isotopic source of 252Cf, at the Faculty of Physics and Nuclear Techniques at the University of Mining and Metallurgy (both neutron source and samples were placed in ''infinite'' polyethylene block). Chemical pretreatment with Na210B12H11SH (BSH) was performed to introduce boron-10 ion into cells in order to check any enhancement effect due to the process of boron neutron capture. Single cell gel electrophoresis also known as the Comet assay was done to investigate the DNA damage. Classical cytogenetic analysis was applied to assess the frequencies of unstable aberrations (dicentrics, rings and a centric fragments). To evaluate the frequencies of stable aberrations the fluorescence in situ hybridisation (FISH) with probes for chromosomes 1, 4 (14.3% of the whole genome) was performed. Linear (or close to linear) increase with radiation dose were observed for the DNA damage and aberration frequencies in lymphocytes both untreated or pre-treated with BSH. Levels of translocations evaluated for the whole genome were comparable with the frequencies of dicentrics and rings. No significant differences were detected due to radiation dose in the frequencies of sister chromatid exchanges (SCE) detected in the second mitosis. No statistically significant differences were observed in various biological end-points between normal or boron pre-treated cells. (author)

  19. Electrolytic production of uranous nitrate

    International Nuclear Information System (INIS)

    Efficient production of uranous nitrate is important in nuclear fuel reprocessing because U(IV) acts as a plutonium reductant in solvent extraction and can be coprecipitated with plutonium and/or throium as oxalates during fuel reprocessing. Experimental conditions are described for the efficient electrolytic production of uranous nitrate for use as a reductant in the SRP Purex process. The bench-scale, continuous-flow, electrolysis cell exhibits a current efficiency approaching 100% in combination with high conversion rates of U(VI) to U(IV) in simulated and actual SRP Purex solutions. High current efficiency is achieved with a voltage-controlled mercury-plated platinum electrode and the use of hydrazine as a nitrite scavenger. Conversion of U(VI) to U(IV) proceeds at 100% efficiency. Cathodic gas generation is minimal. The low rate of gas generation permits a long residence time within the cathode, a necessary condition for high conversions on a continuous basis. Design proposals are given for a plant-scale, continuous-flow unit to meet SRP production requirements. Results from the bench-scale tests indicate that an 8-kW unit can supply sufficient uranous nitrate reductant to meet the needs of the Purex process at SRP

  20. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    Directory of Open Access Journals (Sweden)

    F. Paulot

    2015-09-01

    Full Text Available We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL atmospheric model (AM3. Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting the heterogeneous production of nitric acid to account for the inhibition of N2O5 reactive uptake at high nitrate concentrations. Globally, uncertainties in these processes can impact the simulated nitrate optical depth by up to 25 %, much more than the impact of uncertainties in the seasonality of ammonia emissions (6 % or in the uptake of nitric acid on dust (13 %. Our best estimate for present-day fine nitrate optical depth at 550 nm is 0.006 (0.005–0.008. We only find a modest increase of nitrate optical depth (2 (−40 % and ammonia (+38 % from 2010 to 2050. Nitrate burden is projected to increase in the tropics and in the free troposphere, but to decrease at the surface in the midlatitudes because of lower nitric acid concentrations. Our results suggest that better constraints on the heterogeneous chemistry of nitric acid on dust, on tropical ammonia emissions, and on the transport of ammonia to the free troposphere are needed to improve projections of aerosol optical depth.

  1. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    Science.gov (United States)

    Paulot, F.; Ginoux, P.; Cooke, W. F.; Donner, L. J.; Fan, S.; Lin, M.-Y.; Mao, J.; Naik, V.; Horowitz, L. W.

    2016-02-01

    We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric model (AM3). Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting the heterogeneous production of nitric acid to account for the inhibition of N2O5 reactive uptake at high nitrate concentrations. Globally, uncertainties in these processes can impact the simulated nitrate optical depth by up to 25 %, much more than the impact of uncertainties in the seasonality of ammonia emissions (6 %) or in the uptake of nitric acid on dust (13 %). Our best estimate for fine nitrate optical depth at 550 nm in 2010 is 0.006 (0.005-0.008). In wintertime, nitrate aerosols are simulated to account for over 30 % of the aerosol optical depth over western Europe and North America. Simulated nitrate optical depth increases by less than 30 % (0.0061-0.010) in response to projected changes in anthropogenic emissions from 2010 to 2050 (e.g., -40 % for SO2 and +38 % for ammonia). This increase is primarily driven by greater concentrations of nitrate in the free troposphere, while surface nitrate concentrations decrease in the midlatitudes following lower concentrations of nitric acid. With the projected increase of ammonia emissions, we show that better constraints on the vertical distribution of ammonia (e.g., convective transport and biomass burning injection) and on the sources and sinks of nitric acid (e.g., heterogeneous reaction on dust) are needed to improve estimates of future nitrate optical depth.

  2. Effect of nitrate on microbial perchlorate reduction

    Science.gov (United States)

    Sun, Y.; Coates, J. D.

    2007-12-01

    Over the last decade perchlorate has been recognized as an important emerging water contaminant that poses a significant public health threat. Because of its chemical stability, low ionic charge density, and significant water solubility microbial remediation has been identified as the most feasible method for its in situ attenuation. Our previous studies have demonstrated that dissimilatory perchlorate reducing bacteria (DPRB) capable of the respiratory reduction of perchlorate into innocuous chloride are ubiquitous in soil and sedimentary environments. As part of their metabolism these organisms reduce perchlorate to chlorite which is subsequently dismutated into chloride and molecular oxygen. These initial steps are mediated by the perchlorate reductase and chlorite dismutase enzymes respectively. Previously we found that the activity of these organisms is dependent on the presence of molybdenum and is inhibited by the presence of oxygen and to different extents nitrate. However, to date, there is little understanding of the mechanisms involved in the regulation of perchlorate reduction by oxygen and nitrate. As a continuation of our studies into the factors that control DPRB activity we investigated these regulatory mechanisms in more detail as a model organism, Dechloromonas aromatica strain RCB, transitions from aerobic metabolism through nitrate reduction to perchlorate reduction. In series of growth transition studies where both nitrate and perchlorate were present, preference for nitrate to perchlorate was observed regardless of the nitrate to perchlorate ratio. Even when the organism was pre-grown anaerobically in perchlorate, nitrate was reduced prior to perchlorate. Using non-growth washed cell suspension, perchlorate- grown D. aromatica was capable of reducing both perchlorate and nitrate concomitantly suggesting the preferentially utilization of nitrate was not a result of enzyme functionality. To elucidate the mechanism for preferential utilization of

  3. Fast photolysis of carbonyl nitrates from isoprene

    Science.gov (United States)

    Müller, Jean-Francois; Peeters, Jozef; Stavrakou, Trisevgeni

    2014-05-01

    We show that photolysis is, by far, the major atmospheric sink of isoprene-derived carbonyl nitrates. Empirical evidence from published laboratory studies on the absorption cross sections and photolysis rates of α-nitrooxy ketones suggests that the presence of the nitrate group (i) greatly enhances the absorption cross sections, and (ii) facilitates dissociation to a point that the photolysis quantum yield is close to unity, with O-NO2 dissociation as the likely major channel. On this basis, we provide new recommendations for estimating the cross sections and photolysis rates of carbonyl nitrates. The newly estimated photorates are validated using a chemical box model against measured temporal profiles of carbonyl nitrates in an isoprene oxidation experiment by Paulot et al. (2009). The comparisons for ethanal nitrate and for the sum of methacrolein- and methylvinylketone nitrates strongly supports our assumptions of large cross section enhancements and a near-unit quantum yield for these compounds. These findings have significant atmospheric implications, as carbonyl nitrates constitute an important component of the total organic nitrate pool over vegetated areas: the photorates of key carbonyl nitrates from isoprene are estimated to be typically between ~3 and 20 times higher than their sink due to reaction with OH in relevant atmospheric conditions. Moreover, since the reaction is expected to release NO2, photolysis is especially effective in depleting the total organic nitrate pool.

  4. Nitrate contamination of groundwater and its countermeasures

    Energy Technology Data Exchange (ETDEWEB)

    Mitamura, Hisayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

  5. Nitrate contamination of groundwater and its countermeasures

    International Nuclear Information System (INIS)

    The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

  6. Inhaled plutonium nitrate in dogs

    International Nuclear Information System (INIS)

    The major objective of this project is to determine dose-effect relationships of inhaled plutonium nitrate in dogs to aid in predicting health effects of accidental exposure in man. For lifespan dose-effect studies, beagle dogs were given a single inhalation exposure to 239Pu(NO3)4, in 1976 and 1977. The earliest biological effect was on the hematopoietic system; lymphopenia and neutropenia occurred at the two highest dose levels. The authors have also observed radiation pneumonitis, lung cancer, and bone cancer at the three highest dose levels. 1 figure, 4 tables

  7. Inhaled plutonium nitrate in dogs

    International Nuclear Information System (INIS)

    The major objective of this project is to determine dose-effect relationships of inhaled plutonium nitrate in dogs to aid in predicting health effects of accidental exposure in man. For lifespan dose-effect studies, beagle dogs were given a single inhalation exposure to 239Pu(NO3)4, in 1976 and 1977. The earliest biological effect was on the hematopoietic system; lymphopenia and neutropenia occurred at the two highest dose levels. They have also observed radiation pneumonitis, lung cancer, and bone cancer at the three highest dose levels. 1 figure, 3 tables

  8. Nitrate leaching from Silage Maize

    OpenAIRE

    Hansen, Elly Møller; Eriksen, Jørgen

    2009-01-01

    During the last 20 years the area with maize in Denmark has increased dramatically and reached 163,000 ha in 2008. Silage maize is easy to grow, is a suitable fodder for cows and goes well with grass-clover in the diet. This means that silage maize is often found in crop rotations with grass-clover on sandy soils in western Denmark. The ploughing in of grass-clover fields poses a serious risk of increased nitrate leaching on a coarse sandy soil, even when carried out in spring. With increased...

  9. Water Pollution with Nitrates from Agricultural Sources

    OpenAIRE

    FLESERIU A.; OROIAN I.

    2010-01-01

    One of the biggest water pollution problem is created by nitrates resulted from agriculture. This paper is areview aimin to emphasiz the main water pollution problems produced by nitrates in Romania and EU. The excessnitrates can accumulate in soil in several ways. First, manure effluents containing both ammonia and organic forms ofnitrogen. Organic nitrogen can be converted to ammonia in the soil. The ammonia, together with any ammoniafertilizer applied, is converted to nitrate by soil bacte...

  10. Denitration of Uranyl Nitrate Using Tridodecyl Amine

    International Nuclear Information System (INIS)

    Nitrate extraction from uranyl nitrate using extractant tridodecyl amine and paraffin has been carried out. The aim of this research was to prepare uranyl nitrate with low nitrate content (acid deficiency uranyl nitrate/ADUN). ADUN is a raw material for making kernels uranium oxide in a spherical from which cannot easily be broken/cracked. This ADUN was prepared by extracting nitric acid in uranyl nitrate solution with tridodecyl amine (TDA) and paraffin. Nitric acid in uranyl nitrate solution moved into organic phase due to the complex formation with TDA. The aqueous phase was ADUN, it was than analyzed its nitric and uranium contents using titration method. Tree variables were observed, i.e. uranium contents (80-125 g/l), process temperature (50-100 oC) and TDA/Nitrate molar ratio (0.5-1). Experiment results showed that optimum condition accurate at uranium content of 100 g/l, temperature extraction 60-70 oC and TDA to Nitrate molar ratio 0.75-0.80 with an efficiency of 77 %. (author)

  11. Water Pollution with Nitrates from Agricultural Sources

    Directory of Open Access Journals (Sweden)

    FLESERIU A.

    2010-08-01

    Full Text Available One of the biggest water pollution problem is created by nitrates resulted from agriculture. This paper is areview aimin to emphasiz the main water pollution problems produced by nitrates in Romania and EU. The excessnitrates can accumulate in soil in several ways. First, manure effluents containing both ammonia and organic forms ofnitrogen. Organic nitrogen can be converted to ammonia in the soil. The ammonia, together with any ammoniafertilizer applied, is converted to nitrate by soil bacteria in a process called nitrification. Nitrification is importantbecause plants can only use nitrogen as nitrate. It is equally harmful in both, animals and humans.

  12. Photochemistry of Nitrate Adsorbed on Mineral Dust

    Science.gov (United States)

    Gankanda, A.; Grassian, V. H.

    2013-12-01

    Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

  13. High dose potassium-nitrate chemical dosimeter

    International Nuclear Information System (INIS)

    This dosimeter is used to control 10 kGY-order doses (1 Mrad). Nitrate suffers a radiolitic reduction phenomena, which is related to the given dose. The method to use potassium nitrate as dosimeter is described, as well as effects of the temperature of irradiation, pH, nitrate concentration and post-irradiation stability. Nitrate powder was irradiated at a Semi-Industrial Plant, at Centro Atomico Ezeiza, and also in a Gammacell-220 irradiator. The dose rates used were 2,60 and 1,80 KGY/hour, and the given doses varied between 1,0 and 150 KGY. The uncertainty was +-3% in all the range. (author)

  14. Nitrate reductase assay using sodium nitrate for rapid detection of multidrug resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    Maíra Bidart Macedo

    2012-09-01

    Full Text Available We validated the nitrate reductase assay (NRA for the detection of multidrug-resistant Mycobacterium tuberculosis (MDR-TB using sodium nitrate (NaNO3 in replacement of potassium nitrate (KNO3 as nitrate source. NaNO3 is cheaper than KNO3 and has no restriction on use which facilitates the implementation of NRA to detect MDR-TB.

  15. Evaluation of nitrates in albanian wines

    Directory of Open Access Journals (Sweden)

    Ariola Morina

    2013-05-01

    Full Text Available Nitrates are important compounds in nature but not desirable if they are present in wine at increased amount. The high level of nitrate is attributed to the use of nitrogen fertilizers in the vineyards. Method of the reactive Gries I and Gries II was used for the determination of nitrates in wine. There were analyzed 45 white wines and 55 red wines produced in 2008 – 2010, as well as wines produced from Albanian grape varieties Shesh i Bardhë and Shesh i Zi in 2009 and 2010, as an authentic wines evidence with denominated origin. From the results of analyses was observed that, in 51 % of white wines was found that the content of nitrates were less than 5 mg/l, in 46% of them the nitrates level goes up to 10 mg/l and only in 3 % of them the amount of nitrates is up to 12 mg/l. None of white wine samples have the content of nitrates over 20 mg/l. In this case there is no doubt for water addition during wine preparation. In regards of red wines, in 34% of them the amount of nitrates is up to 5 mg/l, in 30% of them up to 10 mg/l, while in 26% of them the amount of nitrates is 20 mg/l. Only 10 % of red wines have nitrates content over 20 mg/l which raise dubiety for falsified wines where water and sugar is added in the red marc. The level of nitrates in wines with denominated origin was under 20 mg/L.

  16. Nitrate pollution of a karstic groundwater system

    International Nuclear Information System (INIS)

    The Bohemian karst, an extensive karst area formed by Devonian and Silurian limestone, is located SW of Prague. The largest of the karstic springs discharges in the village of Svaty Jan pod Skalou. With about 19 L/s of average discharge, the spring was formerly an important source of good quality drinking water in the ares. Because of increasing agricultural activity after World War II, both shallow and deep water resources, including the karstic systems, have been contaminated by infiltrating nitrates. The nitrate content of the Svaty Jan spring now varies from 40 mg/L to 60 mg/L. To specify the sources of nitrate pollution and collect sufficient data for possible prediction of future development, an extensive study of the spring was initiated in 1994. Flow dynamics, chemical, and isotopic composition (δ18O in water, δ15N in nitrate) are monitored in the spring and precipitation in the recharge area together with possible sources of nitrates (fertilizers, solutes in soil profile). The spring discharge responds to precipitation events very quickly but with a small amplitude and a low variability in δ18O (∼2 per mille). This reflects the large volume of the karstic system that dumps infiltrating precipitation and the low contribution of the direct discharge component. Even more contrasting is the relation between the low variability of nitrate content and periodic changes in δ15N of nitrate (from 5 per mille to 2 per mille). With regard to the specifics of the karstic groundwater system (piston-like flow) two alternative hypotheses of nitrate generation are suggested: (1) different rates of nitrate production in the recharge area and (2) different sources of nitrate localized along the recharge area. To verify the hypotheses, the record of fertilizer applied in the recharge area was studied together with actual nitrate content and its isotopic composition in deep soil profiles. (author)

  17. Nitrate reduction functional genes and nitrate reduction potentials persist in deeper estuarine sediments. Why?

    Directory of Open Access Journals (Sweden)

    Sokratis Papaspyrou

    Full Text Available Denitrification and dissimilatory nitrate reduction to ammonium (DNRA are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the

  18. Nitrate uptake, nitrate reductase distribution and their relation to proton release in five nodulated grain legumes.

    Science.gov (United States)

    Fan, X H; Tang, C; Rengel, Z

    2002-09-01

    Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0.2 and 2 mM nitrate in nutrient solution. Nitrate treatments, imposed on 22-d-old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0.2 mM nitrate supply, nitrate uptake rates ranged from 0.6 to 1.5 mg N g(-1) d(-1) in the order: yellow lupin > field pea (Pisum sativum) > chickpea (Cicer arietinum) > narrow-leafed lupin (L angustifolius) > white lupin (L albus). At 2 mM nitrate supply, nitrate uptake ranged from 1.7 to 8.2 mg N g(-1) d(-1) in the order: field pea > chickpea > white lupin > yellow lupin > narrow-leafed lupin. Nitrate reductase activity increased with increased nitrate supply, with the majority of NRA being present in shoots. Field pea and chickpea had much higher shoot NRA than the three lupin species. When 0.2 mM nitrate was supplied, narrow-leafed lupinreleased the most H+ per unit root biomass per day, followed by yellow lupin, white lupin, field pea and chickpea. At 2 mM nitrate, narrow-leafed lupin and yellow lupin showed net proton release, whereas the other species, especially field pea, showed net OH- release. Irrespective of legume species and nitrate supply, proton release was negatively correlated with nitrate uptake and NRA in shoots, but not with NRA in roots. PMID:12234143

  19. Dietary Nitrate, Nitric Oxide, and Cardiovascular Health.

    Science.gov (United States)

    Bondonno, Catherine P; Croft, Kevin D; Hodgson, Jonathan M

    2016-09-01

    Emerging evidence strongly suggests that dietary nitrate, derived in the diet primarily from vegetables, could contribute to cardiovascular health via effects on nitric oxide (NO) status. NO plays an essential role in cardiovascular health. It is produced via the classical L-arginine-NO-synthase pathway and the recently discovered enterosalivary nitrate-nitrite-NO pathway. The discovery of this alternate pathway has highlighted dietary nitrate as a candidate for the cardioprotective effect of a diet rich in fruit and vegetables. Clinical trials with dietary nitrate have observed improvements in blood pressure, endothelial function, ischemia-reperfusion injury, arterial stiffness, platelet function, and exercise performance with a concomitant augmentation of markers of NO status. While these results are indicative of cardiovascular benefits with dietary nitrate intake, there is still a lingering concern about nitrate in relation to methemoglobinemia, cancer, and cardiovascular disease. It is the purpose of this review to present an overview of NO and its critical role in cardiovascular health; to detail the observed vascular benefits of dietary nitrate intake through effects on NO status as well as to discuss the controversy surrounding the possible toxic effects of nitrate. PMID:25976309

  20. Effect of ammonium nutrition on the nitrate utilization, nitrate reductase actvity and growth of Spirodela polyrrhiza

    Directory of Open Access Journals (Sweden)

    Ewa Tatkowska

    2014-02-01

    Full Text Available The influence of NH4+ ions on nitrate assimilation and growth of sterile Spirodela polyrrhiza cultures was investigated. S. polyrrhiza utilises both the nitrate and the ammonium form of nitrogen, it prefers, however, NH4+. Ammonium ions present in the nitrate medium inhibit the activity of nitrate reductase (NR, but they do not affect enzyme 'induction and only slightly reduce N03- uptake. These results sugest that the inhibitory effect of NH4+ on the NR activity is the main cause of the decrease in N03- assimilation by S. polyrrhiza cultures growing in nitrate-ammonium medium.

  1. Nitrate Transport, Sensing, and Responses in Plants.

    Science.gov (United States)

    O'Brien, José A; Vega, Andrea; Bouguyon, Eléonore; Krouk, Gabriel; Gojon, Alain; Coruzzi, Gloria; Gutiérrez, Rodrigo A

    2016-06-01

    Nitrogen (N) is an essential macronutrient that affects plant growth and development. N is an important component of chlorophyll, amino acids, nucleic acids, and secondary metabolites. Nitrate is one of the most abundant N sources in the soil. Because nitrate and other N nutrients are often limiting, plants have developed sophisticated mechanisms to ensure adequate supply of nutrients in a variable environment. Nitrate is absorbed in the root and mobilized to other organs by nitrate transporters. Nitrate sensing activates signaling pathways that impinge upon molecular, metabolic, physiological, and developmental responses locally and at the whole plant level. With the advent of genomics technologies and genetic tools, important advances in our understanding of nitrate and other N nutrient responses have been achieved in the past decade. Furthermore, techniques that take advantage of natural polymorphisms present in divergent individuals from a single species have been essential in uncovering new components. However, there are still gaps in our understanding of how nitrate signaling affects biological processes in plants. Moreover, we still lack an integrated view of how all the regulatory factors identified interact or crosstalk to orchestrate the myriad N responses plants typically exhibit. In this review, we provide an updated overview of mechanisms by which nitrate is sensed and transported throughout the plant. We discuss signaling components and how nitrate sensing crosstalks with hormonal pathways for developmental responses locally and globally in the plant. Understanding how nitrate impacts on plant metabolism, physiology, and growth and development in plants is key to improving crops for sustainable agriculture. PMID:27212387

  2. Comparative evaluation of nitrate removal technologies

    International Nuclear Information System (INIS)

    Due to the extensive application of artificial nitrogen-based fertilizers and animal manure on land, many water agencies face problems of increasing concentrations of nitrate in groundwater. The contamination of groundwater by nitrate may pose a significant public health problem. The threat of methemoglobinemia is well documented and reflected in the U.S. drinking water standard of 10 mg/L as nitrate-nitrogen. Approximately 45% of Saskatchewan's population use groundwater for drinking purposes, out of which, approximately 23% (230,000) are rural residents. The water used is made available from over 48,000 privately owned wells in regions where there is an extensive application of chemical fertilizers. Biological denitrification, ion exchange and reveres osmosis (RO) processes were selected for further study. Field studies were conducted on these processes. The sulfur/limestone autotrophic denitrification (SLAD) process was selected to achieve biological removal of nitrate from groundwater. The feasibility of the system was evaluated under anaerobic conditions. An ion exchange study was conducted using Ionac A554 which is strong anion exchange resins. In the case of groundwater containing low sulfate concentrations, A554 offered high nitrate removal. However, the disposal of regenerant brine can be a problem. A reverse osmosis unit with Filmtec membrane elements (FT30-Element Family) was used in the study on nitrate removal. The unit effluent average nitrate concentration was less than the maximum allowable concentration. (author)

  3. Microbial Uranium Immobilization Independent of Nitrate Reduction

    International Nuclear Information System (INIS)

    At many uranium processing and handling facilities, including sites in the U.S. Department of Energy (DOE) complex, high levels of nitrate are present as co-contamination with uranium in groundwater. The daunting prospect of complete nitrate removal prior to the reduction of uranium provides a strong incentive to explore bioremediation strategies that allow for uranium bioreduction and stabilization in the presence of nitrate. Typical in-situ strategies involving the stimulation of metal-reducing bacteria are hindered by low pH environments at this study site and require that the persistent nitrate must first and continuously be removed or transformed prior to uranium being a preferred electron acceptor. This project investigates the possibility of stimulating nitrate-indifferent, pH-tolerant microorganisms to achieve bioreduction of U(VI) despite nitrate persistence. Successful enrichments from U-contaminated sediments demonstrated nearly complete reduction of uranium with very little loss of nitrate from pH 4.9-5.6 using methanol or glycerol as a carbon source. Higher pH enrichments also demonstrated similar U reduction capacity with 5-30% nitrate loss within one week. Bacterial 16S rRNA genes were amplified from uranium-reducing enrichments (pH 5.7-6.7) and sequenced. Phylogenetic analyses classified the clone sequences into four distinct clusters. Data from sequencing and T-RFLP profiles indicated that the majority of the microorganisms stimulated by these enrichment conditions consisted of low G+C Gram-positive bacteria most closely related to Clostridium and Clostridium-like organisms. This research demonstrates that the stimulation of a natural microbial community to immobilize U through bioreduction is possible without the removal of nitrate.

  4. Photodegradation of Paracetamol in Nitrate Solution

    Science.gov (United States)

    Meng, Cui; Qu, Ruijuan; Liang, Jinyan; Yang, Xi

    2010-11-01

    The photodegradation of paracetamol in nitrate solution under simulated solar irradiation has been investigated. The degradation rates were compared by varying environmental parameters including concentrations of nitrate ion, humic substance and pH values. The quantifications of paracetamol were conducted by HPLC method. The results demonstrate that the photodegradation of paracetamol followed first-order kinetics. The photoproducts and intermediates of paracetamol in the presence of nitrate ions were identified by extensive GC-MS method. The photodegradation pathways involving. OH radicals as reactive species were proposed.

  5. Photodegradation of Paracetamol in Nitrate Solution

    International Nuclear Information System (INIS)

    The photodegradation of paracetamol in nitrate solution under simulated solar irradiation has been investigated. The degradation rates were compared by varying environmental parameters including concentrations of nitrate ion, humic substance and pH values. The quantifications of paracetamol were conducted by HPLC method. The results demonstrate that the photodegradation of paracetamol followed first-order kinetics. The photoproducts and intermediates of paracetamol in the presence of nitrate ions were identified by extensive GC-MS method. The photodegradation pathways involving. OH radicals as reactive species were proposed.

  6. Historic nitrate storage in groundwater system - a non-negligible process in nitrate water pollution management

    OpenAIRE

    Wang, Lei; Ward, Robert; Stuart, Marianne

    2014-01-01

    Nitrate water pollution is not only an environmental issue but also a threat to the economy and human health. It remains an international problem and has been identified as a major threat to water quality and the delivery of the EU Water Framework and Nitrates Directives targets. It could take decades for nitrate derived from historic fertiliser application, which leaches into groundwater, to travel through thick unsaturated zones (UZs) and saturated zones, and arrive at rivers and boreho...

  7. ROE Wet Nitrate Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  8. Introduction to the nitrate in groundwater papers

    OpenAIRE

    Gooddy, Daren; Besien, T.

    2007-01-01

    Escalating concentrations of nitrate in groundwater supplies resulting from major changes in post-WWII agricultural production were first widely recognised in the 1970s, prompting discussion on the ‘nitrate time-bomb’ problem. The implications of this problem are now becoming clear with increasing numbers of water company groundwater abstractions needing expensive and energy intensive treatment. Since the 1970s, considerable research effort has been directed towards understanding and pred...

  9. Nitrate Concentration in Groundwater in Isfahan Province

    OpenAIRE

    S.F Mousavi; M. Afyuni; A. Jafari Malekabadi; Khosravi, A.

    2004-01-01

    In recent decades, the use of nitrogen fertilizers has increased irrespective of their effects on soil properties, agricultural products and, particularly, on environmental pollution. Nitrate easily leaches from soils into groundwater. The objective of this study was to determine temporal and spatial nitrate concentrations in groundwater in agricultural, industrial and urban regions in some parts of Isfahan Province. Water samples were collected monthly from 75 agricultural, industrial, and u...

  10. Nitrate Contamination of Groundwater: Determinants and Indicators

    OpenAIRE

    Wick, Katharina; Heumesser, Christine; Schmid, Erwin

    2010-01-01

    Nitrogen is an important input to agricultural production but also detrimentally affects the environmental quality of air, soil and water. Identifying the determinants of nitrate pollution and in turn defining sensible performance indicators to design, enforce and monitor regulatory policies is therefore of utmost importance. Using data on more than 1000 Austrian municipalities, we provide a detailed econometric analysis of (1) the determinants of nitrate concentration in groundwater, and (2)...

  11. Nitrate Adsorption on Clay Kaolin: Batch Tests

    OpenAIRE

    Morteza Mohsenipour; Shamsuddin Shahid; Kumars Ebrahimi

    2015-01-01

    Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112...

  12. Is beetroot juice more effective than sodium nitrate? The effects of equimolar nitrate dosages of nitrate-rich beetroot juice and sodium nitrate on oxygen consumption during exercise.

    Science.gov (United States)

    Flueck, Joelle Leonie; Bogdanova, Anna; Mettler, Samuel; Perret, Claudio

    2016-04-01

    Dietary nitrate has been reported to lower oxygen consumption in moderate- and severe-intensity exercise. To date, it is unproven that sodium nitrate (NaNO3(-); NIT) and nitrate-rich beetroot juice (BR) have the same effects on oxygen consumption, blood pressure, and plasma nitrate and nitrite concentrations or not. The aim of this study was to compare the effects of different dosages of NIT and BR on oxygen consumption in male athletes. Twelve healthy, well-trained men (median [minimum; maximum]; peak oxygen consumption: 59.4 mL·min(-1)·kg(-1) [40.5; 67.0]) performed 7 trials on different days, ingesting different nitrate dosages and placebo (PLC). Dosages were 3, 6, and 12 mmol nitrate as concentrated BR or NIT dissolved in plain water. Plasma nitrate and nitrite concentrations were measured before, 3 h after ingestion, and postexercise. Participants cycled for 5 min at moderate intensity and further 8 min at severe intensity. End-exercise oxygen consumption at moderate intensity was not significantly different between the 7 trials (p = 0.08). At severe-intensity exercise, end-exercise oxygen consumption was ∼4% lower in the 6-mmol BR trial compared with the 6-mmol NIT (p = 0.003) trial as well as compared with PLC (p = 0.010). Plasma nitrite and nitrate concentrations were significantly increased after the ingestion of BR and NIT with the highest concentrations in the 12-mmol trials. Plasma nitrite concentration between NIT and BR did not significantly differ in the 6-mmol (p = 0.27) and in the 12-mmol (p = 0.75) trials. In conclusion, BR might reduce oxygen consumption to a greater extent compared with NIT. PMID:26988767

  13. Nitrate concentrations in the Morestead borehole, Twyford

    OpenAIRE

    Stuart, M.E.; Chilton, P J; Newell, A. J.; Butcher, A.S.

    2008-01-01

    This report describes work carried out at Morestead, Twyford as part of a BGS research project “Nitrate Mass Balance in the Saturated Zone”. The project aimed to evaluate the role of the diffusive exchange of nitrate between fracture water and porewater in the saturated zone of the aquifer. The approach adopted attempted to obtain a mass balance for the catchment to a public supply borehole by comparing nitrogen released from the soil with nitrogen held in the aquifer and nitro...

  14. Synthesis of a new energetic nitrate ester

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, David E [Los Alamos National Laboratory

    2008-01-01

    Nitrate esters have been known as useful energetic materials since the discovery of nitroglycerin by Ascanio Sobrero in 1846. The development of methods to increase the safety and utility of nitroglycerin by Alfred Nobel led to the revolutionary improvement in the utility of nitroglycerin in explosive applications in the form of dynamite. Since then, many nitrate esters have been prepared and incorporated into military applications such as double-based propellants, detonators and as energetic plasticizers. Nitrate esters have also been shown to have vasodilatory effects in humans and thus have been studied and used for treatments of ailments such as angina. The mechanism of the biological response towards nitrate esters has been elucidated recently. Interestingly, many of the nitrate esters used for military purposes are liquids (ethylene glycol dinitrate, propylene glycol dinitrate, etc). Pentaerythritol tetranitrate (PETN) is one of the only solid nitrate esters, besides nitrocellulose, that is used in any application. Unfortunately, PETN melting point is above 100 {sup o}C, and thus must be pressed as a solid for detonator applications. A more practical material would be a melt-castable explosive, for potential simplification of manufacturing processes. Herein we describe the synthesis of a new energetic nitrate ester (1) that is a solid at ambient temperatures, has a melting point of 85-86 {sup o}C and has the highest density of any known nitrate ester composed only of carbon, hydrogen, nitrogen and oxygen. We also describe the chemical, thermal and sensitivity properties of 1 as well as some preliminary explosive performance data.

  15. European Community Measures to Reduce Nitrate Pollution

    OpenAIRE

    Al-hedny, Suhad

    2010-01-01

    Water protection proves to be a difficult task, whether it is dealt with through legislation or the implementation of a process to reduce further pollution. This study considers how the issue of water pollution from nitrates in agricultural practices has become better understood through the reforms of the common agriculture policy (CAP) and the enactment of various regulations and directives by EU. The implementation of the EC Nitrate Directive is a main focus of this study because it was a m...

  16. Bio nitrate Project: a new technology for water nitrate elimination by means of ionic exchange resins

    International Nuclear Information System (INIS)

    The use of ion exchange resins for nitrate elimination from water generates a waste containing a sodium chloride mixture plus the retained nitrates. this waste must be correctly disposed. In this project, the resin ionic form is modified to be regenerated with other compounds, different from the common salt, which are interesting because of the presence of mineral nutrition. So, with Bio nitrate Project, nitrates are recovered and the regeneration waste is apt to be use as fertilizer, for agricultural uses, or as complementary contribution of nutrients in biological water treatment. (Author) 27 refs.

  17. Phase relations in the lanthanum nitrate (copper nitrate) - poly(vinylpyrrolidone) - water systems

    International Nuclear Information System (INIS)

    Room-temperature isothermal sections of the phase diagrams of lanthanum nitrate-poly(vinylpyrrolidone)-water and copper nitrate-poly(vinylpyrrolidone)-water systems were studied. The following features were found: a wide region of homogeneous water-polymer solutions, liquid-liquid phase separation field, and a three-phase region in which two liquids coexist with salt crystals. In the lanthanum nitrate system, liquid-liquid phase separation has a lower critical solution point (polythermal sections were studied); in the copper nitrate system, it has an upper critical solution point. The type of diagram for unstudied systems is predicted based on the analysis of polymer-salt phase diagrams

  18. Solvent extraction of rare earth (3) nitrates by trialkylmethylammonium nitrate from multicomponent solutions

    International Nuclear Information System (INIS)

    The extraction of rare earth (3) [praseodymium-lutetium, yttrium (3)] nitrates 0.4-1.10 mol/dm3 by solution of trialkyl-methylammonium in kerosene was studied. It is found that di- and trisolvates of rare earth (3) nitrates is formed in organic phase, extraction constants are determined. Physicochemical and mathematical models descriptive of distribution of metal (3) nitrates in binary and multicomponent systems are given. Optimum field of concentrations of rare earth mixture in rare earths was established during use of solutions of trialkylmethyl-ammonium nitrate in diluent

  19. Californium Recovery from Palladium Wire

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-08-01

    The recovery of 252Cf from palladium-252Cf cermet wires was investigated to determine the feasibility of implementing it into the cermet wire production operation at Oak Ridge National Laboratory’s Radiochemical Engineering Development Center. The dissolution of Pd wire in 8 M HNO3 and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment showed little change in the kinetics of dissolution, which ranged from 0.176 mL/mg down to 0.019 mL/mg. A successful chromatographic separation of 153Gd, a surrogate for 252Cf, from Pd was demonstrated using AG 50x8 cation exchange resin with a bed volume of 0.5 mL and an internal diameter of 0.8 cm.

  20. Supercritical fluid extraction of uranium and neodymium nitrates

    International Nuclear Information System (INIS)

    Supercritical fluid extraction (SFE) of uranyl nitrate and neodymium nitrate salts from a mixture was investigated in the present study using Sc-CO2 modified with various ligands such as organophosphorous compounds, amides, and diketones. Preferential extraction of uranyl nitrate over neodymium nitrate was demonstrated using Sc-CO2 modified with amide, di-(2ethylhexyl) isobutyramide (D2EHIBA). (author)

  1. Groundwater nitrate pollution in intensively farmed regions

    Science.gov (United States)

    Balcerak, Ernie

    2011-12-01

    Intensified agricultural practices that have developed during the past century have helped improve food security for many people but have also added to nitrate pollution in water supply. Balancing the water needs for agriculture with the need for clean groundwater for drinking requires understanding factors such as the routes by which nitrate enters the water supply and how long nitrate remains in the water. The Thames River catchment provides a good study example because the water quality in the river, which supplies drinking water to millions of people, has been monitored for the past 140 years, and the region has undergone significant agricultural development over the past century. Howden et al. studied nitrate transport from agricultural land to water in the Thames basin using a simple model that considers an estimate of the amount of nitrate that could leach the groundwater based on land use practices along with an algorithm that determines the route nitrate would take to reach surface water or groundwater from agricultural areas.

  2. Nitrate Adsorption on Clay Kaolin: Batch Tests

    Directory of Open Access Journals (Sweden)

    Morteza Mohsenipour

    2015-01-01

    Full Text Available Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112.5, 225, and 450 mgNO3-/L, with a constant pH equal to 2, constant temperature equal to 25°C, and exposure period varying from 0 to 150 minutes were considered. The capacity of nitrate adsorption on kaolin has also been studied involving two well-known adsorption isotherm models, namely, Freundlich and Longmuir. The results revealed that approximately 25% of the nitrate present in the solution was adsorbed on clay kaolin. The laboratory experimental data revealed that Freundlich adsorption isotherm model was more accurate than Longmuir adsorption model in predicting of nitrate adsorption. Furthermore, the retardation factor of nitrate pollution in saturated zone has been found to be approximately 4 in presence of kaolin, which indicated that kaolin can be used for natural scavenger of pollution in the environment.

  3. Denitrification inhibition by high nitrate wastes

    International Nuclear Information System (INIS)

    The processing of radioactive metal products at nuclear weapons plants and research labs has produced wastewaters containing high concentrations of nitrate, often greater than 50,000 mg/l N. The adaptation of activated sludge and inhibition of denitrification at high nitrate concentrations was studied using pH controlled bench-scale sequencing batch reactors (SBRs), operated with 50% of the SBR volume recycled (recycle volume = influent volume). Denitrification of 1,350 and 2,700 mg/l NO3--N was completed after approximately 5 hours and 15 hours, respectively. No denitrification of 5,400 mg/l NO3--N was observed. These results suggest that there is a progressive inhibition of denitrification as nitrate concentrations increase from 1,350 to 5,400 mg/l NO3--N. In a subsequent series of experiments at an initial reactor nitrate concentration of 1,350 mg/l N, a significant accumulation of nitrate was observed, resulting once in destabilization with loss of denitrification and once in successful adaptation of the activated sludge. At a nitrate concentration of 1,350 mg/l N, the adaptation of activated sludge appears to be unstable, resulting sometimes in stable denitrification and sometimes in biomass washout

  4. Open-Source Photometric System for Enzymatic Nitrate Quantification

    OpenAIRE

    Wittbrodt, B. T.; Squires, D. A.; Walbeck, J.; Campbell, E.; Campbell, W. H.; Pearce, J. M.

    2015-01-01

    Nitrate, the most oxidized form of nitrogen, is regulated to protect people and animals from harmful levels as there is a large over abundance due to anthropogenic factors. Widespread field testing for nitrate could begin to address the nitrate pollution problem, however, the Cadmium Reduction Method, the leading certified method to detect and quantify nitrate, demands the use of a toxic heavy metal. An alternative, the recently proposed Environmental Protection Agency Nitrate Reductase Nitra...

  5. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    OpenAIRE

    Balk, Melike; Anniet M Laverman; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nit...

  6. Relationships between nitrate uptake and nitrate reductase activity in Cucumis sativus L.

    Directory of Open Access Journals (Sweden)

    Grażyna Kłobus

    2014-02-01

    Full Text Available Anti-NR IgG fragments obtained after papain digestion of polyclonal antibodies gave the positive immunological reaction with both, a soluble and plasma membrane-bound nitrate reductase. Anti-NR antibody as well as IgG fragments almost totally inhibited the nitrate reductase activity in cytosol proving a crossreaction of antibody with the catalytic site of a soluble NR. Anti-NR IgG fragments, but not undigested polyclonal antibodies affected the activity of the nitrate reductase associated with plasma membranes. Discrepancy in the action of intact antibodies and fragments obtained after they digestion were interpreted as a consequence of same differences in the ability of those molecules to the penetration through the membrane. Undigested anti-NR antibody have no effect on the nitrate uptake by intact plants, as well as by the right-side plasma membrane vesicles. On the other hand, IgG fragments of polyclonal antibodies abolished almost totally the nitrate uptake in the case of intact seedlings, but have only slight effect on the N03 uptake in plasma membranes. On the basis of above findings, some relations between nitrate uptake and its assimilation inside the cell are suggested. Since IgG fragments only slightly changed the N03 absorption in vesicles whereas the activity of plasmalemma associated nitrate reductase was strongly repressed, we concluded that the PM-NR is not structurally involved in the nitrate transport through the membrane.

  7. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration*

    Science.gov (United States)

    Olah, George A.; Narang, Subhash C.; Olah, Judith A.

    1981-01-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an α-nitronaphthalene to β-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aromatics. Moodie and Schoefield [Hoggett, J. G., Moodie, R. B., Penton, J. R. & Schoefield, K. (1971) Nitration and Aromatic Reactivity (Cambridge Univ. Press, London)], as well as Perrin, independently concluded that, in the general scheme of nitration of reactive aromatics, there is the necessity to introduce into the classical Ingold mechanism an additional step involving a distinct intermediate preceding the formation of the Wheland intermediate (σ complexes). This view coincides with our two-step mechanistic picture [Kuhn, S. J. & Olah, G. A. (1961) J. Am. Chem. Soc. 83, 4564-4571] of the nitronium salt nitration of aromatic hydrocarbons (including benzene and toluene), in which low substrate selectivity but high positional selectivity was found, indicating the independence of substrate from positional selectivity. PMID:16593026

  8. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration.

    Science.gov (United States)

    Olah, G A; Narang, S C; Olah, J A

    1981-06-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an alpha-nitronaphthalene to beta-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aromatics. Moodie and Schoefield [Hoggett, J. G., Moodie, R. B., Penton, J. R. & Schoefield, K. (1971) Nitration and Aromatic Reactivity (Cambridge Univ. Press, London)], as well as Perrin, independently concluded that, in the general scheme of nitration of reactive aromatics, there is the necessity to introduce into the classical Ingold mechanism an additional step involving a distinct intermediate preceding the formation of the Wheland intermediate (sigma complexes). This view coincides with our two-step mechanistic picture [Kuhn, S. J. & Olah, G. A. (1961) J. Am. Chem. Soc. 83, 4564-4571] of the nitronium salt nitration of aromatic hydrocarbons (including benzene and toluene), in which low substrate selectivity but high positional selectivity was found, indicating the independence of substrate from positional selectivity. PMID:16593026

  9. Imbalance between vertical nitrate flux and nitrate assimilation on a continental shelf: Implications of nitrification

    Science.gov (United States)

    Shiozaki, Takuhei; Furuya, Ken; Kurotori, Hiroyuki; Kodama, Taketoshi; Takeda, Shigenobu; Endoh, Takahiro; Yoshikawa, Yutaka; Ishizaka, Joji; Matsuno, Takeshi

    2011-10-01

    The nitrate assimilation rate and diapycnal nitrate flux were simultaneously determined on the continental shelf of the East China Sea (ECS). Further, the archaeal amoA gene was quantified to examine the potential distribution of nitrification activity. Nitrate assimilation rates and distribution of the archaeal amoA gene were also investigated in the Philippine Sea and in the Kuroshio Current. At all the stations, while the surface nitrate was depleted (amoA was observed at shallower light depths, namely at or above 10% light depth, in the ECS than in other regions, suggesting that nitrification occurred within the euphotic zone in the ECS, especially on the shelf. Moreover, a station on the continental shelf of the ECS exhibited a considerable discrepancy between the nitrate assimilation rate (1500 μmolN m-2 d-1) and vertical nitrate flux (98 μmolN m-2 d-1). Here, 6.7 ± 3.1 × 103 and 2.5 ± 0.7 × 105 copies mL-1 of archaeal amoA were detected at 10% and 1% light depths relative to the surface, respectively. Thus nitrification within the euphotic zone would be attributed at least in part to the observed discrepancy between nitrate assimilation and vertical flux. These observations imply that the assumption of a direct relationship between new production, export production, and measured nitrate assimilation is misplaced, particularly regarding the continental shelf of the ECS.

  10. Nitrate removal and denitrification affected by soil characteristics in nitrate treatment wetlands.

    Science.gov (United States)

    Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan; Chang, Yih-Feng; Shih, Kai-Chung

    2007-03-01

    Several small-scale surface flow constructed wetlands unplanted and planted (monoculture) with various macrophytes (Phragmites australis, Typha orientalis, Pennisetum purpureum, Ipomoea aquatica, and Pistia stratiotes) were established to continuously receive nitrate-contaminated groundwater. Soil characteristics and their effects on nitrate removal and soil denitrification were investigated. The results showed that planted wetland cells exhibited significantly higher (P < 0.05) nitrate removal efficiencies (70-99%) and soil denitrification rates (3.78-15.02 microg N2O-N/g dry soil/h) than an unplanted covered wetland cell (1%, 0.11 microg N2O-N/g/h). However, the unplanted uncovered wetland cell showed a nitrate removal efficiency (55%) lower than but a soil denitrification rate (9.12 microg N2O-N/g/h) comparable to the planted cells. The nitrate removal rate correlated closely and positively with the soil denitrification rate for the planted cells, indicating that soil denitrification is an important process for removing nitrate in constructed wetlands. The results of nitrogen budget revealed that around 68.9-90.7% of the overall nitrogen removal could be attributed to the total denitrification. The soil denitrification rate was found to correlate significantly (P < 0.01) with the extractable organic carbon, organic matter, and in situ-measured redox potential of wetland soil, which accordingly were concluded as suitable indicators of soil denitrification rate and nitrate removal rate in nitrate treatment wetlands. PMID:17365317

  11. Structural and mechanistic insights on nitrate reductases.

    Science.gov (United States)

    Coelho, Catarina; Romão, Maria João

    2015-12-01

    Nitrate reductases (NR) belong to the DMSO reductase family of Mo-containing enzymes and perform key roles in the metabolism of the nitrogen cycle, reducing nitrate to nitrite. Due to variable cell location, structure and function, they have been divided into periplasmic (Nap), cytoplasmic, and membrane-bound (Nar) nitrate reductases. The first crystal structure obtained for a NR was that of the monomeric NapA from Desulfovibrio desulfuricans in 1999. Since then several new crystal structures were solved providing novel insights that led to the revision of the commonly accepted reaction mechanism for periplasmic nitrate reductases. The two crystal structures available for the NarGHI protein are from the same organism (Escherichia coli) and the combination with electrochemical and spectroscopic studies also lead to the proposal of a reaction mechanism for this group of enzymes. Here we present an overview on the current advances in structural and functional aspects of bacterial nitrate reductases, focusing on the mechanistic implications drawn from the crystallographic data. PMID:26362109

  12. Ammonium and nitrate tolerance in lichens

    International Nuclear Information System (INIS)

    Since lichens lack roots and take up water, solutes and gases over the entire thallus surface, these organisms respond more sensitively to changes in atmospheric purity than vascular plants. After centuries where effects of sulphur dioxide and acidity were in the focus of research on atmospheric chemistry and lichens, recently the globally increased levels of ammonia and nitrate increasingly affect lichen vegetation and gave rise to intense research on the tolerance of lichens to nitrogen pollution. The present paper discusses the main findings on the uptake of ammonia and nitrate in the lichen symbiosis and to the tolerance of lichens to eutrophication. Ammonia and nitrate are both efficiently taken up under ambient conditions. The tolerance to high nitrogen levels depends, among others, on the capability of the photobiont to provide sufficient amounts of carbon skeletons for ammonia assimilation. Lowly productive lichens are apparently predisposed to be sensitive to excess nitrogen. - Eutrophication has become a global threat for lichen diversity.

  13. Nitrate reduction in an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Boesen, Carsten; Kristiansen, Henning;

    1991-01-01

    vertical component of the water transport was modeled since, in contrast to rates along flow lines, the vertical rates are close to constant as required by the one-dimensional model. Average vertical transport rates of water in the saturated zone were obtained by tritium dating. The modeling process is a......Nitrate distribution and reduction processes were investigated in an unconfined sandy aquifer of Quaternary age. Groundwater chemistry was studied in a series of eight multilevel samplers along a flow line, deriving water from both arable and forested land. Results show that plumes of nitrate...... processes of O2 and NO3- occur at rates that are fast compared to the rate of downward water transport. Nitrate-contaminated groundwater contains total contents of dissolved ions that are two to four times higher than in groundwater derived from the forested area. The persistence of the high content of...

  14. Trend Analyses of Nitrate in Danish Groundwater

    DEFF Research Database (Denmark)

    Hansen, B.; Thorling, L.; Dalgaard, Tommy;

    2012-01-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis...... of distribution, trends and trend reversals in the groundwater nitrate concentration. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first...... two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded...

  15. Extraction of metal nitrates and nitric acid

    International Nuclear Information System (INIS)

    Considered are the effects of uranyl nitrate extraction with diethyl ether (DE) from binary and ternary solutions. Data are presented describing the extraction of uranyl nitrate at 25 deg C and a characteristic is given for the effect of salinators (NaNO3, Mg(NO3)2, Ca(NO3)2, Sr(NO3)2, Co(NO3)2, Zn(NO3)2 and Cd(NO3)2) on the extraction. A possibility is shown of describing the equilibrium in extraction of micro- and macro-quantities of uranyl nitrate from its binary and ternary solutions. Thermodynamic extraction and distribution constants have been calculated and tabulated basing on the assumption of the nonstochiometric hydration of solvates in organic phase

  16. Nitrate reduction in an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Boesen, Carsten; Kristiansen, Henning; Larsen, Flemming

    1991-01-01

    Nitrate distribution and reduction processes were investigated in an unconfined sandy aquifer of Quaternary age. Groundwater chemistry was studied in a series of eight multilevel samplers along a flow line, deriving water from both arable and forested land. Results show that plumes of nitrate......-contaminated groundwater emanate from the agricultural areas and spread through the aquifer. The aquifer can be subdivided into an upper 10- to 15-m thick oxic zone that contains O2 and NO3-, and a lower anoxic zone characterized by Fe2+-rich waters. The redox boundary is very sharp, which suggests that reduction...... processes of O2 and NO3- occur at rates that are fast compared to the rate of downward water transport. Nitrate-contaminated groundwater contains total contents of dissolved ions that are two to four times higher than in groundwater derived from the forested area. The persistence of the high content of...

  17. Isotope tracing of nitrate : lessons from Malta

    OpenAIRE

    Heaton, Timothy; Stuart, Marianne; Sapiano, M.; Micallef Sultana, M.

    2010-01-01

    Average concentrations of nitrate in Malta’s groundwaters are probably the highest among EU member states. This compromises the quality of an important resource -almost 60% of Malta’s water supply being provided by groundwater. An 15N/14N + 18O/16O isotope study was undertaken as a core part of wide-ranging investigations into the potential sources of the nitrate pollution, its likely future trends, and possible ameliorative actions. The dual isotope (15N/14N + 18O/16O) approach was important...

  18. Factors controlling nitrate cracking of mild steel

    International Nuclear Information System (INIS)

    Nitrite and hydroxide ions inhibit the growth of nitrate stress corrosion cracks in mild steel. Crack growth measurements showed that sufficient concentrations of nitrite and hydroxide ions can prevent crack growth; however, insufficient concentrations of these ions did not influence the Stage II growth rate or the threshold stress intensity, but extended the initiation time. Stage III growth was discontinuous. Oxide formed in the grain boundaries ahead of the crack tip and oxide dissolution (Stage II) and fracture (Stage III) are the proposed mechanisms of nitrate stress corrosion crack growth

  19. Determination of the total nitrate content of thorium nitrate solution with a selective electrode

    International Nuclear Information System (INIS)

    The nitrate content of thorium nitrate solutions is determined with a liquid membrane nitrate selective electrode utilizing the known addition method in 0.1 M potassium fluoride medium as ionic strength adjustor. It is studied the influence of pH and the presence of chloride, sulphate, phosphate, meta-silicate, thorium, rare earths, iron, titanium, uranium and zirconium at the same concentrations as for the aqueous feed solutions in the thorium purification process. The method is tested in synthetic samples and in samples proceeding from nitric dissolutions of thorium hidroxide and thorium oxicarbonate utilized as thorium concentrates to be purified

  20. Degradation of tributylphosphate in plutonium nitrate solution

    International Nuclear Information System (INIS)

    Degradation of tri-n-butylphosphate (TBP) dissolved in aqueous nitrate systems containing Pu was investigated under various conditions. The difference of degradation rates of TBP observed in reprocessed Pu streams and in nitric acid is discussed. The followings were elucidated : (1) The degradation of TBP in plutonium nitrate solutions depends upon the Pu concentration although it indicates first-order kinetics. (2) The half life of TBP increases linearly with HNO3 concentration in plutonium nitrate solutions. The retardation by undissociated HNO3 is almost independent of Pu concentration. (3) No significant effect of HNO2, generated by radiolysis, on the TBP degradation rate was observed. (4) The retardation of the degradation of TBP can be described only with the concentrations of Pu and HNO3. (5) The G-values of TBP in plutonium nitrate solutions extremely decrease with increasing the concentrations of HNO3 and Pu. (6) Plutonium other than undissociated HNO3 would be involved in the retardation due to OH radical scavenging because Pu(III) and Pu(IV) give different degradation rates of TBP. (author)

  1. Biological denitrification of high nitrate waste solutions

    International Nuclear Information System (INIS)

    Biological denitrification of solutions of nitrate salts and weak solutions of nitric acid used in the purification of uranium at the Oak Ridge Y-12 Plant is briefly discussed. Advantages of this system over others are mentioned. Techniques and accumulated experience are covered

  2. The Path to Nitrate Salt Disposition

    Energy Technology Data Exchange (ETDEWEB)

    Funk, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-16

    The topic is presented in a series of slides arranged according to the following outline: LANL nitrate salt incident as thermal runaway (thermally sensitive surrogates, full-scale tests), temperature control for processing, treatment options and down selection, assessment of engineering options, anticipated control set for treatment, and summary of the overall steps for RNS.

  3. Detonation characteristics of ammonium nitrate products

    NARCIS (Netherlands)

    Kersten, R.J.A.; Hengel, E.I.V. van den; Steen, A.C. van der

    2006-01-01

    The detonation properties of ammonium nitrate (AN) products depend on many factors and are therefore, despite the large amount of information on this topic, difficult to assess. In order to further improve the understanding of the safety properties of AN, the European Fertilizer Manufacturers Associ

  4. 76 FR 46907 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-08-03

    ... common example is when fertilizer-grade ammonium nitrate is mixed with fuel oil and creates an explosive... Requirements 1. Mixture Requirement 2. Threshold Weight and Individual Products Exemptions 3. Explosives... Federal Bureau of Investigation FR Federal Register HMR Hazardous Materials Regulations HMT...

  5. Nitrate Salt Surrogate Blending Scoping Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-13

    Test blending equipment identified in the “Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing”. Determine if the equipment will provide adequate mixing of zeolite and surrogate salt/Swheat stream; optimize equipment type and operational sequencing; impact of baffles and inserts on mixing performance; and means of validating mixing performance

  6. Denitration of High Nitrate Salts Using Reductants

    Energy Technology Data Exchange (ETDEWEB)

    HD Smith; EO Jones; AJ Schmidt; AH Zacher; MD Brown; MR Elmore; SR Gano

    1999-05-03

    This report describes work conducted by Pacific Northwest National Laboratory (PNNL), in conjunction with Idaho National Engineering and Environmental Laboratory (INEEL), to remove nitrates in simulated low-activity waste (LAW). The major objective of this work was to provide data for identifying and demonstrating a technically viable and cost-effective approach to condition LAW for immobilization (grout).

  7. Nitrates, Nitrites, and Health. Bulletin 750.

    Science.gov (United States)

    Deeb, Barbara S.; Sloan, Kenneth W.

    This review is intended to assess available literature in order to define the range of nitrate/nitrite effects on animals. Though the literature deals primarily with livestock and experimental animals, much of the contemporary research is concerned with human nitrite intoxication. Thus, the effects on man are discussed where appropriate. Some of…

  8. Electroreduction of uranyl ion in aqueous calcium nitrate solutions

    International Nuclear Information System (INIS)

    The electroreduction of uranyl ions in buffered and unbuffered 0.5 M calcium nitrate has been studied using polarography, cyclic voltammetry, chronopotentiometry, and chronoamperometry. The results are compared with those in molten calcium nitrate tetrahydrate. (author)

  9. Evidence for a plasma-membrane-bound nitrate reductase involved in nitrate uptake of Chlorella sorokiniana

    Science.gov (United States)

    Tischner, R.; Ward, M. R.; Huffaker, R. C.

    1989-01-01

    Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.

  10. Heating efficiency of microwave heating direct denitration of a mixture of uranyl nitrate and plutonium nitrate

    International Nuclear Information System (INIS)

    A mixture of plutonium nitrate and uranyl nitrate is co-converted to MOX powder by the microwave heating method developed by JAEA. The heating efficiency is very important for improving the energy-saving performance in this conversion process. In this study, the heating efficiency was measured using both experimental and engineering-scale microwave ovens in water, nitric acid and a mixture of plutonium nitrate and uranyl nitrate as a function of distance between the specimen and the base of the oven. In addition, the distribution of electromagnetic field strength and its absorption concentration in the solution were numerically evaluated by an electromagnetic field analysis code, MWS 2009. The experimental results could almost be explained by the numerical analysis results. When the distance of the specimen and the base of the oven was beyond 1/4 wavelength, the efficiency became constant because the influence disappeared. (author)

  11. Nitrates in surface waters, inputs and seasonality: Phase 2

    OpenAIRE

    Casey, H.; Clarke, R. T.; Smith, S.

    1988-01-01

    Changes in management practices and agricultural productivity over the past twenty years have lead to nitrate pollution and eutrophication of lakes and rivers. Information on nitrate concentrations and discharge has been collected on the River Frome at East Stoke since 1965, using the same analytical nitrate method so that the results are comparable. These records of weekly spot values of nitrate concentration and daily mean discharges have been analysed for trends and seasonal patterns in bo...

  12. Atmospheric near surface nitrate at coastal Antarctic sites

    OpenAIRE

    D. Wagenbach; Legrand, M; Fischer, H.; Pichlmayer, F.; E. W. Wolff

    1998-01-01

    Records of atmospheric nitrate were obtained by year-round aerosol sampling at Neumayer and Dumont D'Urville stations, located in the Atlantic and Pacific sector of coastal Antarctica, respectively. Where possible, evaluation of the nitrate records is mainly based on concurrently measured radioisotopes (10Be, 7Be, 210Pb) as well as δ15N in nitrate nitrogen. Observations made at these (and two other coastal Antarctic sites [Savoie et al., 1993]) reveal a uniform nitrate background near 10 ng m...

  13. Spatial assessment of animal manure spreading and groundwater nitrate pollution

    OpenAIRE

    Roberta Infascelli; Raffaele Pelorosso; Lorenzo Boccia

    2009-01-01

    Nitrate concentration in groundwater has frequently been linked to non-point pollution. At the same time the existence of intensive agriculture and extremely intensive livestock activity increases the potential for nitrate pollution in shallow groundwater. Nitrate used in agriculture could cause adverse effects on human and animal health. In order to evaluate the groundwater nitrate pollution, and how it might evolve in time, it is essential to develop control systems and to improve policies ...

  14. Nitrate mass balance in the Padež stream watershed

    OpenAIRE

    Česnik, Katarina

    2014-01-01

    Graduation thesis analyzes changes in nitrate mass balance in a forested watersheds. The nitrate mass balance changes occur manly because of hydrological and biogeochemical mechanisms. The studied area, the Padež stream watershed, is mainly covered with forest. Between years 2006 and 2007 the hydrometeorological conditions and streamwater chemistry of Padež stream were continuously monitored. The differences in streamwater nitrate concentrations and nitrate concentrations in precipitations an...

  15. Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252; Diseno de un reactor nuclear subcritico homogeneo a base de Torio con una fuente de Californio 252

    Energy Technology Data Exchange (ETDEWEB)

    Delgado H, C. E.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Sajo B, L., E-mail: ce_delgado89@hotmail.com [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of)

    2015-10-15

    Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U{sup 233} when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO{sub 2}(NO{sub 3}){sub 4} and 18% of thorium Th(NO{sub 3}){sub 4} as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 10{sup 7} s{sup -1}. In the design the value of the effective multiplication factor, whose value turned out k{sub eff} <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

  16. Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source; Determinacao de manganes em minerios, por analise por ativacao, usando californio-252 como fonte de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Antonio

    1976-07-01

    Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction {sup 55}Mn (n.gamma){sup 56} Mn, high concentration of manganese in the matrix and short half - life of {sup 56}Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions {sup 56}Fe(n,p){sup 56}Mn and {sup 59} Co (n, {alpha}){sup 56} were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

  17. Electrochemical processing of nitrate waste solutions

    International Nuclear Information System (INIS)

    The second phase of research performed at The Electrosynthesis Co., Inc. has demonstrated the successful removal of nitrite and nitrate from a synthetic effluent stream via a direct electrochemical reduction at a cathode. It was shown that direct reduction occurs at good current efficiencies in 1,000 hour studies. The membrane separation process is not readily achievable for the removal of nitrites and nitrates due to poor current efficiencies and membrane stability problems. A direct reduction process was studied at various cathode materials in a flow cell using the complete synthetic mix. Lead was found to be the cathode material of choice, displaying good current efficiencies and stability in short and long term tests under conditions of high temperature and high current density. Several anode materials were studied in both undivided and divided cell configurations. A divided cell configuration was preferable because it would prevent re-oxidation of nitrite by the anode. The technical objective of eliminating electrode fouling and solids formation was achieved although anode materials which had demonstrated good stability in short term divided cell tests corroded in 1,000 hour experiments. The cause for corrosion is thought to be F- ions from the synthetic mix migrating across the cation exchange membrane and forming HF in the acid anolyte. Other possibilities for anode materials were explored. A membrane separation process was investigated which employs an anion and cation exchange membrane to remove nitrite and nitrate, recovering caustic and nitric acid. Present research has shown poor current efficiencies for nitrite and nitrate transport across the anion exchange membrane due to co-migration of hydroxide anions. Precipitates form within the anion exchange membranes which would eventually result in the failure of the membranes. Electrochemical processing offers a highly promising and viable method for the treatment of nitrate waste solutions

  18. Amperometric nitrate biosensor based on Carbon nanotube/Polypyrrole/Nitrate reductase biofilm electrode

    International Nuclear Information System (INIS)

    This study describes the construction and characterization of an amperometric nitrate biosensor based on the Polypyrrole (PPy)/Carbon nanotubes (CNTs) film. Nitrate reductase (NR) was both entrapped into the growing PPy film and chemically immobilized via the carboxyl groups of CNTs to the CNT/PPy film electrode. The optimum amperometric response for nitrate was obtained in 0.1 M phosphate buffer solution (PBS), pH 7.5 including 0.1 M lithium chloride and 7 mM potassium ferricyanide with an applied potential of 0.13 V (vs. Ag/AgCl, 3 M NaCl). Sensitivity was found to be 300 nA/mM in a linear range of 0.44–1.45 mM with a regression coefficient of 0.97. The biosensor response showed a higher linear range in comparison to standard nitrate analysis methods which were tested in this study and NADH based nitrate biosensors. A minimum detectable concentration of 0.17 mM (S/N = 3) with a relative standard deviation (RSD) of 5.4% (n = 7) was obtained for the biosensor. Phenol and glucose inhibit the electrochemical reaction strictly at a concentration of 1 μg/L and 20 mg/L, respectively. The biosensor response retained 70% of its initial response over 10 day usage period when used everyday. - Highlights: ► K3Fe(CN)6 has been used for the first time as mediator for nitrate reductase. ► Better performance was obtained in comparison to other nitrate biosensor studies operated with various mediators. ► Analytical parameters were better than standard nitrate analysis methods.

  19. Solubility of uranyl nitrate in nitric acid solutions of aluminum nitrate

    International Nuclear Information System (INIS)

    The solubility of uranyl nitrate in nitric acid solutions of aluminum nitrate at 250C containing 10, 20 and 30 mass % of nitric acid has been studied by the isothermal method. The Schreinemakers method has been used to establish the composition of the solid phases, which has been confirmed by crystallographic and thermographic studies. Data are presented on the viscosity and density of saturated solutions

  20. Amperometric nitrate biosensor based on Carbon nanotube/Polypyrrole/Nitrate reductase biofilm electrode

    Energy Technology Data Exchange (ETDEWEB)

    Can, Faruk; Korkut Ozoner, Seyda; Ergenekon, Pinar; Erhan, Elif, E-mail: e.erhan@gyte.edu.tr

    2012-01-01

    This study describes the construction and characterization of an amperometric nitrate biosensor based on the Polypyrrole (PPy)/Carbon nanotubes (CNTs) film. Nitrate reductase (NR) was both entrapped into the growing PPy film and chemically immobilized via the carboxyl groups of CNTs to the CNT/PPy film electrode. The optimum amperometric response for nitrate was obtained in 0.1 M phosphate buffer solution (PBS), pH 7.5 including 0.1 M lithium chloride and 7 mM potassium ferricyanide with an applied potential of 0.13 V (vs. Ag/AgCl, 3 M NaCl). Sensitivity was found to be 300 nA/mM in a linear range of 0.44-1.45 mM with a regression coefficient of 0.97. The biosensor response showed a higher linear range in comparison to standard nitrate analysis methods which were tested in this study and NADH based nitrate biosensors. A minimum detectable concentration of 0.17 mM (S/N = 3) with a relative standard deviation (RSD) of 5.4% (n = 7) was obtained for the biosensor. Phenol and glucose inhibit the electrochemical reaction strictly at a concentration of 1 {mu}g/L and 20 mg/L, respectively. The biosensor response retained 70% of its initial response over 10 day usage period when used everyday. - Highlights: Black-Right-Pointing-Pointer K{sub 3}Fe(CN){sub 6} has been used for the first time as mediator for nitrate reductase. Black-Right-Pointing-Pointer Better performance was obtained in comparison to other nitrate biosensor studies operated with various mediators. Black-Right-Pointing-Pointer Analytical parameters were better than standard nitrate analysis methods.

  1. Disposable nitrate-selective optical sensor based on fluorescent dye

    Science.gov (United States)

    A simple, disposable thin-film optical nitrate sensor was developed. The sensor was fabricated by applying a nitrate-selective polymer membrane on the surface of a thin polyester film. The membrane was composed of polyvinylchloride (PVC), plasticizer, fluorescent dye, and nitrate-selective ionophore...

  2. Nitrate to ammonia ceramic (NAC) bench scale stabilization study

    Energy Technology Data Exchange (ETDEWEB)

    Caime, W.J.; Hoeffner, S.L. [RUST - Clemson Technical Center, Anderson, SC (United States)

    1995-10-01

    Department of Energy (DOE) sites such as the Hanford site, Idaho National Engineering Laboratory (INEL), Savannah River site, Oak Ridge National Laboratory (ORNL) have large quantities of sodium-nitrate based liquid wastes. A process to reduce the nitrates to ammonia has been developed at ORNL. This technology creates a sludge lower in nitrates. This report describes stabilization possibilities of the sludge.

  3. Nitrate removal by electro-bioremediation technology in Korean soil

    International Nuclear Information System (INIS)

    The nitrate concentration of surface has become a serious concern in agricultural industry through out the world. In the present study, nitrate was removed in the soil by employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics. The abundance of Bacillus spp. as nitrate reducing bacteria were isolated and identified from the soil sample collected from a greenhouse at Jinju City of Gyengsangnamdo, South Korea. The nitrate reducing bacterial species were identified by 16 s RNA sequencing technique. The efficiency of bacterial isolates on nitrate removal in broth was tested. The experiment was conducted in an electrokinetic (EK) cell by applying 20 V across the electrodes. The nitrate reducing bacteria (Bacillus spp.) were inoculated in the soil for nitrate removal process by the addition of necessary nutrient. The influence of nitrate reducers on electrokinetic process was also studied. The concentration of nitrate at anodic area of soil was higher when compared to cathode in electrokinetic system, while adding bacteria in EK (EK + bio) system, the nitrate concentration was almost nil in all the area of soil. The bacteria supplies electron from organic degradation (humic substances) and enhances NO3- reduction (denitrification). Experimental results showed that the electro-bio kinetic process viz. electroosmosis and physiological activity of bacteria reduced nitrate in soil environment effectively. Involvement of Bacillus spp. on nitrification was controlled by electrokinetics at cathode area by reduction of ammonium ions to nitrogen gas. The excellence of the combined electro-bio kinetics technology on nitrate removal is discussed.

  4. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    NARCIS (Netherlands)

    Balk, Melike; Laverman, A.M.; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought

  5. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a component of articles intended for use in...

  6. Laboratory study of nitrate photolysis in Antarctic snow

    DEFF Research Database (Denmark)

    Berhanu, Tesfaye A.; Meusinger, Carl; Erbland, Joseph;

    2014-01-01

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [" Laboratory study of nitrate photolysis in Antarc...... reproduce the stable isotopic composition of nitrate found in Antarctic snow profiles. © 2014 Author(s)....

  7. 9 CFR 319.2 - Products and nitrates and nitrites.

    Science.gov (United States)

    2010-01-01

    ... standard in this part and to which nitrate or nitrite is permitted or required to be added, may be prepared without nitrate or nitrite and labeled with such standard name when immediately preceded with the term... to such product as commonly prepared with nitrate and nitrite: And provided further, That...

  8. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    International Nuclear Information System (INIS)

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660±0.092 at 25 C, and extraction enthalpy is -5. 46±0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 x 106±3.56 x 104 at 25 C; reaction enthalpy was -9.610±0.594 kcal/mol. Nitration complexation constant is 8.412±0.579, with an enthalpy of -10.72±1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured

  9. The nitrate time bomb : a numerical way to investigate nitrate storage and lag time in the unsaturated zone

    OpenAIRE

    Wang, L.; Butcher, A.S.; Stuart, M E; Gooddy, D.C.; Bloomfield, J.P.

    2013-01-01

    Nitrate pollution in groundwater, which is mainly from agricultural activities, remains an international problem. It threatens the environment, economics and human health. There is a rising trend in nitrate concentrations in many UK groundwater bodies. Research has shown it can take decades for leached nitrate from the soil to discharge into groundwater and surface water due to the ‘store’ of nitrate and its potentially long travel time in the unsaturated and satura...

  10. Catalytic hydrogenation of uranyl nitrate - engineering scale studies

    International Nuclear Information System (INIS)

    Uranous nitrate is employed as partitioning agent for the separation of plutonium from uranium in PUREX process, the conventional process for the reprocessing of spent nuclear fuel. It is currently produced from uranyl nitrate solution by the electrochemical route. Since the conversion is only 50%, an innovative method based on catalytic hydrogenation has been developed. Parametric studies have been carried out on 5 L scale using natural uranyl nitrate solution as fed. Based on these studies, number of runs were carried out on engineering scale using contaminated uranyl nitrate solution. More than 100 kg of uranous nitrate has been made. Performance of the reduction process is described in detail. (author)

  11. Groundwater pollution by nitrates from livestock wastes.

    OpenAIRE

    Goldberg, V M

    1989-01-01

    Utilization of wastes from livestock complexes for irrigation involves the danger of groundwater pollution by nitrates. In order to prevent and minimize pollution, it is necessary to apply geological-hydrogeological evidence and concepts to the situation of wastewater irrigation for the purposes of studying natural groundwater protectiveness and predicting changes in groundwater quality as a result of infiltrating wastes. The procedure of protectiveness evaluation and quality prediction is de...

  12. Potential of dietary nitrate in angiogenesis.

    Science.gov (United States)

    Rammos, Christos; Luedike, Peter; Hendgen-Cotta, Ulrike; Rassaf, Tienush

    2015-10-26

    Endothelial dysfunction with impaired bioavailability of nitric oxide (NO) is the hallmark in the development of cardiovascular disease. Endothelial dysfunction leads to atherosclerosis, characterized by chronic inflammation of the arterial wall and stepwise narrowing of the vessel lumen. Atherosclerosis causes deprivation of adequate tissue blood flow with compromised oxygen supply. To overcome this undersupply, remodeling of the vascular network is necessary to reconstitute and sustain tissue viability. This physiological response is often not sufficient and therapeutic angiogenesis remains an unmet medical need in critical limb ischemia or coronary artery disease. Feasible approaches to promote blood vessel formation are sparse. Administration of pro-angiogenic factors, gene therapy, or targeting of microRNAs has not yet entered the daily practice. Nitric oxide is an important mediator of angiogenesis that becomes limited under ischemic conditions and the maintenance of NO availability might constitute an attractive therapeutic target. Until recently it was unknown how the organism provides NO under ischemia. In recent years it could be demonstrated that NO can be formed independently of its enzymatic synthesis in the endothelium by reduction of inorganic nitrite under hypoxic conditions. Circulating nitrite derives from oxidation of NO or reduction of inorganic nitrate by commensal bacteria in the oral cavity. Intriguingly, nitrate is a common constituent of our everyday diet and particularly high concentrations are found in leafy green vegetables such as spinach, lettuce, or beetroot. Evidence suggests that dietary nitrate supplementation increases the regenerative capacity of ischemic tissue and that this effect may offer an attractive nutrition-based strategy to improve ischemia-induced revascularization. We here summarize and discuss the regenerative capacity of dietary nitrate on the vascular system. PMID:26516419

  13. Potential of dietary nitrate in angiogenesis

    Institute of Scientific and Technical Information of China (English)

    Christos; Rammos; Peter; Luedike; Ulrike; Hendgen-Cotta; Tienush; Rassaf

    2015-01-01

    Endothelial dysfunction with impaired bioavailability of nitric oxide(NO) is the hallmark in the development of cardiovascular disease. Endothelial dysfunction leads to atherosclerosis, characterized by chronic inflammation of the arterial wall and stepwise narrowing of the vessel lumen. Atherosclerosis causes deprivation of adequate tissue blood flow with compromised oxygen supply. To overcome this undersupply, remodeling of the vascular network is necessary to reconstitute and sustain tissue viability. This physiological response is often not sufficient and therapeutic angiogenesis remains an unmet medical need in critical limb ischemia or coronary artery disease. Feasible approaches to promote blood vessel formation are sparse. Administration of pro-angiogenic factors, gene therapy, or targeting of micro RNAs has not yet entered the daily practice. Nitric oxide is an important mediator of angiogenesis that becomes limited under ischemic conditions and the maintenance of NO availability might constitute an attractive therapeutic target. Until recently it was unknown how the organism provides NO under ischemia. In recent years it could be demonstrated that NO can be formed independently of its enzymatic synthesis in the endothelium by reduction of inorganic nitrite under hypoxic conditions. Circulating nitrite derives from oxidation of NO or reduction of inorganic nitrate by commensal bacteria in the oral cavity. Intriguingly, nitrate is a common constituent of our everyday diet and particularly high concentrations are found in leafy green vegetables such as spinach, lettuce, or beetroot. Evidence suggests that dietary nitrate supplementation increases the regenerative capacity of ischemic tissue and that this effect may offer an attractive nutrition-based strategy to improve ischemia-induced revascularization. We here summarize and discuss the regenerative capacity of dietary nitrate on the vascular system.

  14. Nitrates - loss processes in raw water

    OpenAIRE

    Hall, G. H.

    1988-01-01

    This project investigated the production of nitrate (nitrification) by bacteria in lakes. The work was undertaken as nitrification is a key process in the nitrogen cycle and previous estimates of rates of nitrification were unreliable. When different methods were used to estimate rates of nitrification within sediment deposits different results were obtained. Investigation' of specific aspects of these methodologies has allowed some rationalization of these observations and also enabled compa...

  15. Supplemental Cooling for Nitrate Salt Waste

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Mitchell S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-19

    In July 2015, Los Alamos National Laboratory completed installation of a supplemental cooling system in the structure where remediated nitrate salt waste drums are stored. Although the waste currently is in a safe configuration and is monitored daily,controlling the temperature inside the structure adds another layer of protection for workers, the public,and the environment.This effort is among several layers of precautions designed to secure the waste.

  16. Biological denitrification of nitrate waste solutions

    International Nuclear Information System (INIS)

    Based on careful laboratory and pilot-plant work, the Y-12 Plant of the Nuclear Division of Union Carbide has designs to construct and operate a three-phase plant to eliminate nitrate as a potential pollutant of ground water. A still is being installed to distill and recover free nitric acid from condensates and raffinate for recycle in production operations. A crystallizer is in the process of being purchased and installed to recover and recycle Al(NO3)3.9H2O. The 25,000-gallon (95 m3) modified water-softening tanks with associated stirring equipment, plumbing, pumps and controls have been purchased. Either one or both of these vessels will be utilized as biological denitrifiers dependent upon the quantity of nitrate requiring disposal at any given time. One denitrifier may be utilized to maintain a standby working colony or culture of bacteria and simultaneously achieve an even lower nitrate concentration in the effluent stream than the present 40 to 100 mg/dm3 of solution. (U.S.)

  17. Organic Nitrates: A Complex Family of Atmospheric Trace Constituents

    Science.gov (United States)

    Ballschmiter, K.; Fischer, R. G.; Grünert, A.; Kastler, J.; Schneider, M.; Woidich, S.

    2003-04-01

    Biogenic and geogenic hydrocarbons are the precursors of organic nitrates that are formed as tropospheric photo-oxidation products in the presence of NOx. Air chemistry leads to a very complex pattern of nitric acid esters: alkyl nitrates, aryl-alkyl nitrates, and bifunctional nitrates like alkyl dinitrates, hydroxy alkyl nitrates and carbonyl alkyl nitrates. We have analyzed the pattern of organic nitrates in air samples after adsorption/thermal desorption (low volume sampling-LVS) or adsorption/solvent desorption (high volume sampling-HVS) by capillary gas chromatography with electron capture (ECD) and mass spectrometric detection (MSD) using air aliquotes of 100 up to 3000 liters on column. The complexity of the organic nitrates found in air requires a group pre-separation by normal phase liquid chromatography. A detection limit per compound of 0.005 ppt(v) is achieved by our approach. We have synthesized a broad spectrum of organic nitrates as reference compounds. Air samples were taken from central Europe, the US West (Utah, Nevada, California), and the North- and South Atlantic including Antarctica. Levels and patterns of the regional and global occurrence of the various groups of C1-C12 organic nitrates including dinitrates and hydroxy nitrates and nitrates of isoprene (2-methylbutadiene) are presented. Werner G., J. Kastler, R. Looser, K. Ballschmiter: "Organic nitrates of isoprene as atmospheric trace compounds" Angewandte Chemie - International Edition (1999) 38: 1634-1637. Woidich S., O. Froescheis, O. Luxenhofer, K. Ballschmiter: "EI- and NCI-mass spectrometry of arylalkyl nitrates and their occurrence in urban air" Fresenius J. Anal. Chem. (1999) 364 : 91-99. Kastler, J; Jarman, W; Ballschmiter, K.: "Multifunctional organic nitrates as constituents in European and US urban photo-smog" Fresenius J. Anal. Chem. (2000) 368:244-249. Schneider M., K. Ballschmiter: "C3-C14 alkyl nitrates in remote South Atlantic air" Chemosphere (1999) 38: 233-244. Fischer

  18. Amperometric nitrate biosensor based on Carbon nanotube/Polypyrrole/Nitrate reductase biofilm electrode.

    Science.gov (United States)

    Can, Faruk; Korkut Ozoner, Seyda; Ergenekon, Pinar; Erhan, Elif

    2012-01-01

    This study describes the construction and characterization of an amperometric nitrate biosensor based on the Polypyrrole (PPy)/Carbon nanotubes (CNTs) film. Nitrate reductase (NR) was both entrapped into the growing PPy film and chemically immobilized via the carboxyl groups of CNTs to the CNT/PPy film electrode. The optimum amperometric response for nitrate was obtained in 0.1 M phosphate buffer solution (PBS), pH 7.5 including 0.1 M lithium chloride and 7 mM potassium ferricyanide with an applied potential of 0.13 V (vs. Ag/AgCl, 3 M NaCl). Sensitivity was found to be 300 nA/mM in a linear range of 0.44-1.45 mM with a regression coefficient of 0.97. The biosensor response showed a higher linear range in comparison to standard nitrate analysis methods which were tested in this study and NADH based nitrate biosensors. A minimum detectable concentration of 0.17 mM (S/N=3) with a relative standard deviation (RSD) of 5.4% (n=7) was obtained for the biosensor. Phenol and glucose inhibit the electrochemical reaction strictly at a concentration of 1 μg/L and 20 mg/L, respectively. The biosensor response retained 70% of its initial response over 10 day usage period when used everyday. PMID:23177766

  19. Reductive denitrification of nitrate by scrap iron filings

    Institute of Scientific and Technical Information of China (English)

    HAO Zhi-wei; XU Xin-hua; WANG Da-hui

    2005-01-01

    Reduction of nitrate by zero-valent iron is a highly exergonic reaction that has long been known to occur. Use of scrap iron filings (SIF) as the PRB (Permeable Reactive Barrier) material can be used to recycle certain by-products, and identify cheaper replacements for expensive conventional PRB materials, especially pure metallic iron. The feasibility of reductive denitrification of nitrate by SIF was studied by batch experiments. Operational parameters such as pH value, SIF dosage and initial concentration of nitrate were investigated. The removal efficiency of nitrate reached 80% under the conditions of pH of 2.5, nitrate initial concentration of 45 mg/L and SIF dosage of 100 g/L within 4 h. Results indicated that nitrate removal is inversely related to pH. Low pH value condition favors for the nitrate transformation. Different from the results of others who studied nitrate reduction using iron powder, we found that there was a lag time before nitrate reduction occurs, even at low pH. Finally, the possible mechanism of nitrate reduction by Fe0 is discussed.

  20. Canopy and seasonal profiles of nitrate reductase in soybeans

    Energy Technology Data Exchange (ETDEWEB)

    Harper, J.E.; Hageman, R.H.

    1972-01-01

    Nitrate reductase activity of soybeans (Glycine max L. Merr.) was evaluated in soil plots and outdoor hydroponic gravel culture systems throughout the growing season. Nitrate reductase profiles within the plant canopy were also established. Mean activity per gram fresh weight per hour of the entire plant canopy was highest in the seedling stage while total activity (activity per gram fresh weight per hour times the total leaf weight) reached a maximum when plants were in the full bloom to midpod fill stage. Nitrate reductase activity per gram fresh weight per hour was highest in the uppermost leaf just prior to full expansion and declined with leaf positions lower in the canopy. Total nitrate reductase activity per leaf was also highest in the uppermost fully expanded leaf during early growth stages. Maximum total activity shifted to leaf positions lower in the plant canopy with later growth stages. Nitrate reductase activity of soybeans grown in hydroponic systems was significantly higher than activity of adjacent soil grown plants at later growth stages, which suggested that under normal field conditions the potential for nitrate utilization may not be realized. Nitrate reductase activity per gram fresh weight per hour and nitrate content were positively correlated over the growing season with plants grown in either soil or solution culture. Computations based upon the nitrate reductase assay of plants grown in hydroponics indicated that from 1.7 to 1.8 grams N could have been supplied to the plant via the nitrate reductase process. 11 references, 9 figures, 3 tables.

  1. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    KAUST Repository

    Balk, Melike

    2015-03-02

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  2. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    Science.gov (United States)

    Balk, Melike; Laverman, Anniet M; Keuskamp, Joost A; Laanbroek, Hendrikus J

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils. PMID:25784903

  3. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    Directory of Open Access Journals (Sweden)

    Melike eBalk

    2015-03-01

    Full Text Available Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests.The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden under the nitrate-limited conditions of most mangrove forest soils.

  4. Extraction of uranyl nitrate from aqueous nitrate solutions by open cell polyurethane foam sponge (OCPUFS)

    International Nuclear Information System (INIS)

    The extraction of uranyl nitrate into open cell polyurethane foam sponge (OCPUFS) from aqueous solution, in the presence of salting agents, was examined. The extraction efficiency was observed to depend on the concentration of uranyl and nitrate ions. The charge of the cation was also found to influence the distribution ratio. The effect of the change in temperature and pH was also studied. The results are interpreted in terms of OCPUFS acting as a viscous organic ether of moderate dielectric constant. (author) 14 refs.; 6 figs

  5. NITRATE DESTRUCTION LITERATURE SURVEY AND EVALUATION CRITERIA

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J.

    2011-02-01

    This report satisfies the initial phase of Task WP-2.3.4 Alternative Sodium Recovery Technology, Subtask 1; Develop Near-Tank Nitrate/Nitrite Destruction Technology. Some of the more common anions in carbon steel waste tanks at SRS and Hanford Site are nitrate which is corrosive, and nitrite and hydroxide which are corrosion inhibitors. At present it is necessary to periodically add large quantities of 50 wt% caustic to waste tanks. There are three primary reasons for this addition. First, when the contents of salt tanks are dissolved, sodium hydroxide preferentially dissolves and is removed. During the dissolution process the concentration of free hydroxide in the tank liquid can decrease from 9 M to less than 0.2 M. As a result, roughly half way through the dissolution process large quantities of sodium hydroxide must be added to the tank to comply with requirements for corrosion control. Second, hydroxide is continuously consumed by reaction with carbon dioxide which occurs naturally in purge air used to prevent buildup of hydrogen gas inside the tanks. The hydrogen is generated by radiolysis of water. Third, increasing the concentration of hydroxide increases solubility of some aluminum compounds, which is desirable in processing waste. A process that converts nitrate and nitrite to hydroxide would reduce certain costs. (1) Less caustic would be purchased. (2) Some of the aluminum solid compounds in the waste tanks would become more soluble so less mass of solids would be sent to High Level Vitrification and therefore it would be not be necessary to make as much expensive high level vitrified product. (3) Less mass of sodium would be fed to Saltstone at SRS or Low Level Vitrification at Hanford Site so it would not be necessary to make as much low level product. (4) At SRS less nitrite and nitrate would be sent to Defense Waste Processing Facility (DWPF) so less formic acid would be consumed there and less hydrogen gas would be generated. This task involves

  6. Nitrate Destruction Literature Survey And Evaluation Criteria

    International Nuclear Information System (INIS)

    This report satisfies the initial phase of Task WP-2.3.4 Alternative Sodium Recovery Technology, Subtask 1; Develop Near-Tank Nitrate/Nitrite Destruction Technology. Some of the more common anions in carbon steel waste tanks at SRS and Hanford Site are nitrate which is corrosive, and nitrite and hydroxide which are corrosion inhibitors. At present it is necessary to periodically add large quantities of 50 wt% caustic to waste tanks. There are three primary reasons for this addition. First, when the contents of salt tanks are dissolved, sodium hydroxide preferentially dissolves and is removed. During the dissolution process the concentration of free hydroxide in the tank liquid can decrease from 9 M to less than 0.2 M. As a result, roughly half way through the dissolution process large quantities of sodium hydroxide must be added to the tank to comply with requirements for corrosion control. Second, hydroxide is continuously consumed by reaction with carbon dioxide which occurs naturally in purge air used to prevent buildup of hydrogen gas inside the tanks. The hydrogen is generated by radiolysis of water. Third, increasing the concentration of hydroxide increases solubility of some aluminum compounds, which is desirable in processing waste. A process that converts nitrate and nitrite to hydroxide would reduce certain costs. (1) Less caustic would be purchased. (2) Some of the aluminum solid compounds in the waste tanks would become more soluble so less mass of solids would be sent to High Level Vitrification and therefore it would be not be necessary to make as much expensive high level vitrified product. (3) Less mass of sodium would be fed to Saltstone at SRS or Low Level Vitrification at Hanford Site so it would not be necessary to make as much low level product. (4) At SRS less nitrite and nitrate would be sent to Defense Waste Processing Facility (DWPF) so less formic acid would be consumed there and less hydrogen gas would be generated. This task involves

  7. Accumulation of Nitrate in Vegetables and Its Possible Implications to Human Health

    Institute of Scientific and Technical Information of China (English)

    DU Shao-ting; ZHANG Yong-song; LIN Xian-yong

    2007-01-01

    In recent times, there are two kinds of completely opposite viewpoints about the impacts of nitrate on human health. To further objectively understand the effects of nitrate on human health, both of harmfulness and possible benefits of nitrate to human body, it is discussed in this review from the aspects of nitrate accumulation in vegetables, the source of nitrate ingested into human body, and the transformation of nitrate in human body, as well as the pathogenesis and physiological functions of nitrate metabolism.

  8. Evaluating Ecosystem Services for Reducing Groundwater Nitrate Contamination: Nitrate Attenuation in the Unsaturated and Saturated Zones

    Science.gov (United States)

    Wang, J.

    2013-12-01

    Nitrates are the most common type of groundwater contamination in agricultural regions. Environmental policies targeting nitrates have focused on input control (e.g., restricted fertilizer application), intermediate loads control (e.g., reduce nitrate leached from crop fields), and final loads control (e.g., reduce catchment nitrate loads). Nitrate loads can be affected by hydrological processes in both unsaturated and saturated zones. Although many of these processes have been extensively investigated in literature, they are commonly modeled as exogenous to farm management. A couple of recent studies by scientists from the Lawrence Livermore National Laboratory show that in some situations nitrate attenuation processes in the unsaturated/saturated zone, particularly denitrification, can be intensified by certain management practices to mitigate nitrate loads. Therefore, these nitrate attenuation processes can be regarded as a set of ecosystem services that farmers can take advantage of to reduce their cost of complying with environmental policies. In this paper, a representative California dairy farm is used as a case study to show how such ecosystem attenuation services can be framed within the farm owner's decision-making framework as an option for reducing groundwater nitrate contamination. I develop an integrated dynamic model, where the farmer maximizes discounted net farm profit over multiple periods subject to environmental regulations. The model consists of three submodels: animal-waste-crop, hydrologic, and economic model. In addition to common choice variables such as irrigation, fertilization, and waste disposal options, the farmer can also endogenously choose from three water sources: surface water, deep groundwater (old groundwater in the deep aquifer that is not affected by farm effluent in the short term), and shallow groundwater (drainage water that can be recycled via capture wells at the downstream end of the farm). The capture wells not only

  9. Nitrate sources and sinks in Elkhorn Slough, California: Results from long-term continuous in situ nitrate analyzers

    Science.gov (United States)

    Chapin, T.P.; Caffrey, J.M.; Jannasch, H.W.; Coletti, L.J.; Haskins, J.C.; Johnson, K.S.

    2004-01-01

    Nitrate and water quality parameters (temperature, salinity, dissolved oxygen, turbidity, and depth) were measured continuously with in situ NO 3 analyzers and water quality sondes at two sites in Elkhorn Slough in Central California. The Main Channel site near the mouth of Elkhorn Slough was sampled from February to September 2001. Azevedo Pond, a shallow tidal pond bordering agricultural fields further inland, was sampled from December 1999 to July 2001. Nitrate concentrations were recorded hourly while salinity, temperature, depth, oxygen, and turbidity were recorded every 30 min. Nitrate concentrations at the Main Channel site ranged from 5 to 65 ??M. The propagation of an internal wave carrying water from ???100 m depth up the Monterey Submarine Canyon and into the lower section of Elkhorn Slough on every rising tide was a major source of nitrate, accounting for 80-90% of the nitrogen load during the dry summer period. Nitrate concentrations in Azevedo Pond ranged from 0-20 ??M during the dry summer months. Nitrate in Azevedo Pond increased to over 450 ??M during a heavy winter precipitation event, and interannual variability driven by differences in precipitation was observed. At both sites, tidal cycling was the dominant forcing, often changing nitrate concentrations by 5-fold or more within a few hours. Water volume flux estimates were combined with observed nitrate concentrations to obtain nitrate fluxes. Nitrate flux calculations indicated a loss of 4 mmol NO3 m -2 d-1 for the entire Elkhorn Slough and 1 mmol NO 3 m-2 d-1 at Azevedo Pond. These results suggested that the waters of Elkhorn Slough were not a major source of nitrate to Monterey Bay but actually a nitrate sink during the dry season. The limited winter data at the Main Channel site suggest that nitrate was exported from Elkhorn Slough during the wet season. Export of ammonium or dissolved organic nitrogen, which we did not monitor, may balance some or all of the NO 3 flux.

  10. Sustainability of natural attenuation of nitrate in agricultural aquifers

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  11. Evaluation of ferrocyanide/nitrate explosive hazard

    International Nuclear Information System (INIS)

    Los Alamos National Laboratory agreed to assist Pacific Northwest Laboratory in the Ferrocyanide Safety Evaluation Program by helping to evaluate the explosive hazard of several mixtures of simulated ferrocyanide waste-tank sludge containing sodium nitrite and sodium nitrate. This report is an evaluation of the small-scale safety tests used to assess the safety of these materials from an explosive point of view. These tests show that these materials are not initiated by mechanical insult, and they require an external heat source before any exothermic chemical reaction can be observed

  12. Electrospun cellulose nitrate and polycaprolactone blended nanofibers

    Science.gov (United States)

    Nartker, Steven; Hassan, Mohamed; Stogsdill, Michael

    2015-03-01

    Pure cellulose nitrate (CN) and blends of CN and polycaprolactone were electrospun to form nonwoven mats. Polymers were dissolved in a mixed solvent system of tetrahydrofuran and N,N-dimethylformamide. The concentrations were varied to obtain sub-micron and nanoscale fiber mats. Fiber mats were analyzed using scanning electron microscopy, contact angle analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The fiber morphology, surface chemistry and contact angle data show that these electrospun materials are suitable for applications including biosensing, biomedical and tissue engineering.

  13. Periplasmic nitrate reductases: structural and spectroscopic studies

    OpenAIRE

    Javier Gonzalez, Pablo

    2006-01-01

    Dissertação apresentada para obtenção do grau de Doutor em Bioquímica, especialidade Bioquímica-Física, pela Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa Nitrate reduction occurs in the cell in order to incorporate nitrogen into biomolecules(assimilatory ammonification), as the final electron acceptor when bacteria are grown in anaerobic conditions (denitrification/dissimilatory ammonification) and to eliminate energy excess generated by the cell metabolism (dissimi...

  14. Biological denitrification of nitrate waste solutions

    International Nuclear Information System (INIS)

    The studies leading to the design of the Oak Ridge Y-12 plant biological denitrification system are briefly described. The system uses a flow-through stirred-bed reactor. Methanol and lime-neutralized acetic acid were evaluated as C sources. The acetic acid was selected because the calcium carbonate generated in the process is needed for neutralization of the acid wastes. Excess organic will be used to ensure maximum amount of nitrate destroyed. The system will generate solids in the form of calcium carbonate, aluminum hydroxide, and organic carbon and N2 and CO2 gases. (JSR)

  15. Simple approximation of nitrate diffusion from saltstone

    International Nuclear Information System (INIS)

    This report describes: (1) The justification for using one dimensional semi-infinite solid, with zero surface concentration, as an adequate model for saltstone leaching. (2) A simplified model involving leaching from a monolith into a well stirred tank to describe the transient salt concentration in the soil as the water in it migrates toward the saturated zone. (3) The effect, on the flux of sodium nitrate into the soil, of a slab of material such as clay or cement, placed between the saltstone and soil. It is assumed that the material in intermediate between that of the saltstone and soil

  16. Nitrate Paradigm Does Not Hold Up for Sugarcane

    OpenAIRE

    Robinson, Nicole; Brackin, Richard; Vinall, Kerry; Soper, Fiona; Holst, Jirko; Gamage, Harshi; Paungfoo-Lonhienne, Chanyarat; Rennenberg, Heinz; Lakshmanan, Prakash; Schmidt, Susanne

    2011-01-01

    Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N) for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer applications in main producer countries raise doubt about the sustainability of production and are at o...

  17. Assessment of nitrate contamination risk: The Italian experience

    OpenAIRE

    Capri, E.; Delgado Huertas, Antonio; VASSALLO, M

    2009-01-01

    The purpose of this study is to show the results of the Italian research project of national interest (PRIN) launched in 2006 and finished in 2008, concerning the “assessment of groundwater contamination risk by nitrates assessment”. The project verified the IPNOA method for nitrate groundwater contamination risk assessment in four test-sites of Italy. The IPNOA is a parametric index which assesses the potential hazard of nitrate contamination originating from agriculture on a regional scale....

  18. Nitrate sensing and cell wall modification in Staphylococci

    OpenAIRE

    Niemann, Volker

    2015-01-01

    This thesis highlights two topics concerning the regulation of energy metabolism and the cell wall biosynthesis in Staphylococci. Most members of this genus are facultative anaerobic microorganisms able to respire on nitrate as final electron acceptor. The completely apathogenic organism Staphylococcus carnosus is used as starter culture in food industry. Dissimilatory nitrate reduction causes desired effects during the ripening process of sausages. First, the nitrate concentra...

  19. Nitrate pollution in groundwater: source identification using isotope ratio

    International Nuclear Information System (INIS)

    Isotope ratios for identification of pollutant source is an emerging scientific tool. An investigation was carried out to find out the origin of nitrate in groundwater in an area which receives pollutant of different origin like inorganic fertilizers, organic manures besides urban wastes. The δ15N values of nitrate clearly indicated the possibility of groundwater pollution by nitrate originating from human and animal wastes. (author)

  20. Effects of long-term dietary nitrate supplementation in mice

    OpenAIRE

    Hezel, Michael P.; Ming Liu; Tomas A. Schiffer; Larsen, Filip J.; Antonio Checa; Wheelock, Craig E; Mattias Carlström; Lundberg, Jon O.; Eddie Weitzberg

    2015-01-01

    Background: Inorganic nitrate (NO3-) is a precursor of nitric oxide (NO) in the body and a large number of short-term studies with dietary nitrate supplementation in animals and humans show beneficial effects on cardiovascular health, exercise efficiency, host defense and ischemia reperfusion injury. In contrast, there is a long withstanding concern regarding the putative adverse effects of chronic nitrate exposure related to cancer and adverse hormonal effects. To address these concerns we p...

  1. The effect of light on nitrate uptake by wheat roots

    Directory of Open Access Journals (Sweden)

    Jinzhi Li

    2013-09-01

    Full Text Available Illuminating shoots stimulates nitrate uptake by wheat (Triticum aestivum L. cv. ‘EM18’ roots. A method with a high time resolution (minutes, non-invasive technique, has enabled to measure the nitrate uptake time coarsely. The nitrate uptake by wheat roots increases in the light and decreases in the dark. The mechanism is thought to be via a signal carried in phloem, probably a sugar.

  2. Nitrate paradigm does not hold up for sugarcane.

    Directory of Open Access Journals (Sweden)

    Nicole Robinson

    Full Text Available Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer applications in main producer countries raise doubt about the sustainability of production and are at odds with a carbon-based crop. Examining reasons for the inefficient use of N fertilizer, we hypothesized that sugarcane resembles other giant tropical grasses which inhibit the production of nitrate in soil and differ from related grain crops with a confirmed ability to use nitrate. The results of our study support the hypothesis that N-replete sugarcane and ancestral species in the Andropogoneae supertribe strongly prefer ammonium over nitrate. Sugarcane differs from grain crops, sorghum and maize, which acquired both N sources equally well, while giant grass, Erianthus, displayed an intermediate ability to use nitrate. We conclude that discrimination against nitrate and a low capacity to store nitrate in shoots prevents commercial sugarcane varieties from taking advantage of the high nitrate concentrations in fertilized soils in the first three months of the growing season, leaving nitrate vulnerable to loss. Our study addresses a major caveat of sugarcane production and affords a strong basis for improvement through breeding cultivars with enhanced capacity to use nitrate as well as through agronomic measures that reduce nitrification in soil.

  3. A nitrate sensitive planar optode; performance and interferences

    DEFF Research Database (Denmark)

    Pedersen, Lasse; Dechesne, Arnaud; Smets, Barth F.

    2015-01-01

    We present a newly developed nitrate sensitive planar optode. It exhibits a linear response to nitrate from 1 to 50 mM at pH 8.0, a fast response time below 10 s and a good lifetime, allowing for fast two dimensional nitrate measurements over long periods of time. Interference from nitrite, chlor......, chloride and thiocyanate, however, limits the optode's application in environments where these are encountered, notably seawater with its high chloride content....

  4. Nitrate Pollution in Inland Waters: Causes, Consequences and Policy

    OpenAIRE

    Raimundo Viejo Rubio

    2003-01-01

    This paper considers the problems related with excessive concentration of nitrates in inland waters. According to recent concerns about the level of nitrates in water, the British situation will be studied. Potential health and environmental problems are examined given new evidence for their linkage with nitrate concentrations. The paper will also consider the role that water companies play when treating polluted water and charging consumers for water supply. Current legislation dealing with ...

  5. Nitrate leaching in grazed grasslands of different composition and age

    OpenAIRE

    Eriksen, J.; Vinther, F.P.

    2002-01-01

    In a field experiment at Research Centre Foulum a suction cup technique was used to investigate nitrate leaching from grassland depending on composition (grass-clover or perennial ryegrass), management (grazing or cutting) and age of the swards. In 1997-2001 was investigated the successive nitrate leaching from 4-7 year old grazed grass-clover and ryegrass with cut plots of similar age and spring barley as reference. In 2000-2001 the simultaneous nitrate leaching from newly established swards...

  6. NITRATE AND NITRITE CONCENTRATION IN VEGETABLES GRAWING AROUND ISFAHAN CITY

    OpenAIRE

    R.A JAFARI; A AZIZ ZADEH; A FARZAN

    2001-01-01

    Introduction: The improper and excess use of chemical fertilizers by the farmers special in "urea" form may cause the commulation of nitrates and nitrites in vegetables and fruits. This investigation has been done to determine the concentration of nitrates and nitrites in some vegetables growing around Isfahan. Methods: One hundred and thirteen random samples from 15 different kinds of green lest tuber vegetables were measured by Cadmium Column Procedure for nitrates and nitrites. R...

  7. The effectiveness of nitrate vulnerable zones for limiting surface water nitrate concentrations

    Science.gov (United States)

    Worrall, F.; Spencer, E.; Burt, T. P.

    2009-05-01

    SummaryThis study considers the surface water concentrations of nitrate in areas designated as nitrate vulnerable zones (NVZs) for between 12 and 15 years. The study proposes a range of tests of the effectiveness of nitrate management within the NVZs and in particular the results from within NVZs were compared to a range of controls. The tests show that: Sixty-nine percent of NVZs showed no significant improvement in surface water concentrations even after 15 years. In comparison to a control catchment 29% of NVZs showed a significant improvement but 31% showed a significant worsening. The average improvement relative to a control due to NVZ designation was 0.02 ± 0.08 mg N/l/yr. Differences between NVZs could not be significantly related to the size of the NVZ, uptake of the scheme, extent of uptake, land use change or geology of the local aquifer. Land use data suggest that NVZ designation buffered the designated areas against wider changes in arable farming in England and helped maintain a higher proportion of arable within the areas than would be expected. The lack of objective success for NVZ designation suggests that nitrate pollution control strategies based on input management need to be rethought.

  8. Impact of Sulfide on Nitrate Conversion in Eutrophic Nitrate-Rich Marine Sludge

    DEFF Research Database (Denmark)

    Schwermer, Carsten U.; Krieger, Bärbel; Lavik, Gaute;

    2006-01-01

    Environmental Sciences, Volcani Research Center, Bet-Dagan, Israel Multiple anaerobic processes are responsible for carbon mineralization in eutrophic nitrate-rich marine environments (e.g., upwelling areas, estuaries, and aquacultures), involving electron acceptors from both the nitrogen and sulfur cycle. The...

  9. Impacts of drainage water management on subsurface drain flow, nitrate concentration, and nitrate loads in Indiana

    Science.gov (United States)

    Drainage water management is a conservation practice that has the potential to reduce drainage outflow and nitrate (NO3) loss from agricultural fields while maintaining or improving crop yields. The goal of this study was to quantify the impact of drainage water management on dra...

  10. Multiple mechanisms of nitrate sensing by Arabidopsis nitrate transceptor NRT1.1

    Czech Academy of Sciences Publication Activity Database

    Bouguyon, E.; Brun, F.; Meynard, D.; Kubeš, Martin; Pervent, M.; Leran, S.; Lacombe, B.; Krouk, G.; Guiderdoni, E.; Zažímalová, Eva; Hoyerová, Klára; Nacry, P.; Gojon, A.

    2015-01-01

    Roč. 1, March (2015), s. 15015. ISSN 2055-026X R&D Projects: GA ČR(CZ) GAP305/11/0797 Institutional support: RVO:61389030 Keywords : nitrate transceptor * Arabidopsis * lateral root development Subject RIV: EB - Genetics ; Molecular Biology

  11. Pitting behavior of 2024 aluminum alloy in nitrate solutions

    International Nuclear Information System (INIS)

    Pitting of 2024 aluminum alloy was investigated in chloride-containing nitrate solutions. Potentiostatic and potentiokinetic experiments followed by examination of the sample surface were performed in order to relate the pitting behavior of the alloy to its microstructure. The SEM examination showed that copper-rich particles were preferential sites for pitting. These particles started dissolving during the polarization in nitrate solutions due to the agressivity of nitrate ions toward copper. In the presence of chloride ions, these particles were completely dissolved. Nitrate ions on the other hand appeared to have a very strong inhibitory effect toward pitting in the aluminum matrix. (author)

  12. Aluminum nitrate recrystallization and recovery from liquid extraction raffinates

    International Nuclear Information System (INIS)

    The solid sludges resulting form biodenitrification of discarded aluminum nitrate are the largest Y-12 Plant process solid waste. Aluminum nitrate feedstocks also represent a major plant materials cost. The chemical constraints on aluminum nitrate recycle were investigated to determine the feasibility of increasing recycle while maintaining acceptable aluminum nitrate purity. Reported phase behavior of analogous systems, together with bench research, indicated that it would be possible to raise the recycle rate from 35% to between 70 and 90% by successive concentration and recrystallization of the mother liquor. A full scale pilot test successfully confirmed the ability to obtain 70% recycle in existing process equipment

  13. Endogenously Nitrated Proteins in Mouse Brain: Links To Neurodegenerative Disease

    Energy Technology Data Exchange (ETDEWEB)

    Sacksteder, Colette A.; Qian, Weijun; Knyushko, Tanya V.; Wang, Haixing H.; Chin, Mark H.; Lacan, Goran; Melega, William P.; Camp, David G.; Smith, Richard D.; Smith, Desmond J.; Squier, Thomas C.; Bigelow, Diana J.

    2006-07-04

    Increased nitrotyrosine modification of proteins has been documented in multiple pathologies in a variety of tissue types; emerging evidence suggests its additional role in redox regulation of normal metabolism. In order to identify proteins sensitive to nitrating conditions in vivo, a comprehensive proteomic dataset identifying 7,792 proteins from whole mouse brain, generated by LC/LC-MS/MS analyses, was used to identify nitrated proteins. This analysis resulted in identification of 31 unique nitrotyrosine sites within 29 different proteins. Over half of the nitrated proteins identified have been reported to be involved in Parkinson's disease, Alzheimer's disease, or other neurodegenerative disorders. Similarly, nitrotyrosine immunoblots of whole brain homogenates show that treatment of mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), an experimental model of Parkinson's disease, induces increased nitration of the same protein bands observed to be nitrated in brains of untreated animals. Comparing sequences and available high resolution structures around nitrated tyrosines with those of unmodified sites indicates a preference of nitration in vivo for surface accessible tyrosines in loops, characteristics consistent with peroxynitrite-induced tyrosine modification. More striking is the five-fold greater nitration of tyrosines having nearby basic sidechains, suggesting electrostatic attraction of basic groups with the negative charge of peroxynitrite. Together, these results suggest that elevated peroxynitrite generation plays a role in neurodegenerative changes in the brain and provides a predictive tool of functionally important sites of nitration.

  14. Regioselective nitration of aromatic substrates in zeolite cages

    Indian Academy of Sciences (India)

    T Esakkidurai; M Kumarraja; K Pitchumani

    2003-04-01

    Phenol is nitrated regioselectively by fuming nitric acid inside the cages of faujasite zeolites (dependent on the loading level) and a remarkable orthoselectivity is observed in solid state nitration. Toluene and chlorobenzene also containing ortho-/para-orienting substituents, undergo faster nitration, though the regioselectivity is less significant in zeolite media. The results are explained on the basis of diffusion and binding of phenol inside zeolite, which facilitate regioselectivity (and which is absent in toluene and chlorobenzene). Other advantages of employing zeolites as media for mild and selective nitration are also highlighted.

  15. Development of technology for ammonium nitrate dissociation process

    International Nuclear Information System (INIS)

    Ammonia and ammonium carbonate are frequently used as reagents in fuel production and processing of liquid radioactive wastes. In particular, liquid radioactive wastes that contain ammonium nitrate are generated during operations of metal precipitation. In closed vessels at elevated temperature, for example in evaporators or deposits in tubing, ammonium nitrate may explode due to generation of gaseous nitrogen oxides [2]. In this connection, steps have to be taken to rule out conditions that result in explosion. To do that, ammonium nitrate should be removed even prior to the initial stage of its formation. This report gives results of development of a method of dissociating ammonium nitrate

  16. Significant accumulation of nitrate in Chinese semi-humid croplands

    Science.gov (United States)

    Zhou, Junyu; Gu, Baojing; Schlesinger, William H.; Ju, Xiaotang

    2016-04-01

    Soil nitrate is important for crop growth, but it can also leach to groundwater causing nitrate contamination, a threat to human health. Here, we report a significant accumulation of soil nitrate in Chinese semi-humid croplands based upon more than 7000 samples from 141 sites collected from 1994 to 2015. In the 0–4 meters depth of soil, total nitrate accumulation reaches 453 ± 39, 749 ± 75, 1191 ± 89, 1269 ± 114, 2155 ± 330 kg N ha‑1 on average in wheat, maize, open-field vegetables (OFV), solar plastic-roofed greenhouse vegetables (GHV) and orchard fields, respectively. Surprisingly, there is also a comparable amount of nitrate accumulated in the vadose-zone deeper than 4 meters. Over-use of N fertilizer (and/or manure) and a declining groundwater table are the major causes for this huge nitrate reservoir in the vadose-zone of semi-humid croplands, where the nitrate cannot be denitrified due to the presence of oxygen and lack of carbon sources. Future climatic change with more extreme rainfall events would increase the risk of accumulated nitrate moving downwards and threatening groundwater nitrate contamination.

  17. Hydrothermal oxidation of organic wastes using reclaimed ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Proesmans, P.I.; Luan, L.; Buelow, S.J.

    1996-04-01

    Ammonium nitrate is being studied as an alternative for ammonium perchlorate as an oxidizing agent in Department of Defense 1.1 and 1.3 rocket propellants. Use of ammonium nitrate would eliminate the HCl produced by ammonium perchlorate upon thermal decomposition. To stabilize the ammonium nitrate, which suffers from phase instability, potassium dinitramide (KDN) is added. This increased use of ammonium nitrate will ultimately create a need for environmentally responsible processes to reuse ammonium nitrate extracted from demilitarized rocket motors. Ammonium Nitrate was investigated as an oxidizing agent for methanol, acetic acid and phenol. High removal of organic, ammonia and nitrate was achieved at stoichiometric concentrations. The oxidation of ammonia by nitrate was much faster than the oxidation of either methanol or acetic acid. Phenol, however, was in strong competition with ammonia for the oxidizer (nitrate). Nitrogen products included N{sub 2}, N{sub 2}O, NO{sub 2{sup {minus}}} as well as toxic NO and trace amounts of NO{sub 2}. Carbon products were CO{sub 2}, HCO{sub 3{sup {minus}}}, CO{sub 3}{sup 2{minus}}, and CO.

  18. Crystallization of sodium nitrate from radioactive waste

    International Nuclear Information System (INIS)

    From the 1940s to the 1980s, the Institute of Physical Chemistry of the Russian Academy of Sciences (IPC/RAS) conducted research and development on processes to separate acetate and nitrate salts and acetic acid from radioactive wastes by crystallization. The research objective was to decrease waste volumes and produce the separated decontaminated materials for recycle. This report presents an account of the IPC/RAS experience in this field. Details on operating conditions, waste and product compositions, decontamination factors, and process equipment are described. The research and development was generally related to the management of intermediate-level radioactive wastes. The waste solutions resulted from recovery and processing of uranium, plutonium, and other products from irradiated nuclear fuel, neutralization of nuclear process solutions after extractant recovery, regeneration of process nitric acid, equipment decontamination, and other radiochemical processes. Waste components include nitric acid, metal nitrate and acetate salts, organic impurities, and surfactants. Waste management operations generally consist of two stages: volume reduction and processing of the concentrates for storage, solidification, and disposal. Filtration, coprecipitation, coagulation, evaporation, and sorption were used to reduce waste volume. 28 figs., 40 tabs

  19. New infrared spectroscopic database for bromine nitrate

    Science.gov (United States)

    Wagner, Georg; Birk, Manfred

    2016-08-01

    Fourier transform infrared measurements of bromine nitrate have been performed in the spectral region 675-1400 cm-1 at 0.014 cm-1 spectral resolution. Absorption cross sections were derived from 38 spectra covering the temperature range from 203 to 296 K and air pressure range from 0 to 190 mbar. For line-by-line analysis, further spectra were recorded at 0.00094 cm-1 spectral resolution at 223 and 293 K. The sample was synthesized from ClONO2 and Br2. Band strengths of the bands ν3 around 803 cm-1 and ν2 around 1286 cm-1 were determined from three pure BrONO2 measurements at different temperatures and pressures. Number densities in the absorption cell were derived from pressure measurements of the purified sample taking into account small amounts of impurities determined spectroscopically. Resulting band strengths are Sν3 = 2.872(52) × 10-17 cm2 molec-1 cm-1 and Sν2 = 3.63(15) × 10-17 cm2 molec-1 cm-1. Absorption cross sections of all measurements were scaled to these band strengths. Further data reduction was achieved with an interpolation scheme based on two-dimensional polynomials in ln(pressure) and temperature. The database is well-suited for remote-sensing application and should reduce the atmospheric bromine nitrate error budget substantially.

  20. Thermal decomposition of supported lithium nitrate catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Maria Lucia [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Lick, Ileana Daniela [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina); Ponzi, Marta Isabel [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Castellon, Enrique Rodriguez; Jimenez-Lopez, Antonio [Departamento de Quimica Inorganica, Cristalografia y Mineralogia. Facultad de Ciencias, Universidad de Malaga, Campus de Teatinos, 29071 Malaga (Spain); Ponzi, Esther Natalia, E-mail: eponzi@quimica.unlp.edu.ar [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina)

    2010-02-20

    New catalysts for soot combustion were prepared by impregnation of different supports (SiO{sub 2}, ZrO{sub 2} and ZrO{sub 2}.nH{sub 2}O) with a LiNO{sub 3} solution and then characterized by means of FTIR, XPS, TGA and UV-vis spectroscopy, whereby the presence of lithium nitrate in the prepared catalysts was identified and quantified. The soot combustion rate using this series of catalysts (LiNO{sub 3}/support) was compared with the activity of a series of impregnated catalysts prepared using LiOH (Li{sub 2}O/supports). Catalysts prepared using LiNO{sub 3} are found to be more active than those prepared using LiOH. The catalytic performance was also studied with a NO/O{sub 2} mixture in the feed, demonstrating that NO increases the combustion rate of soot, probably as a consequence of lithium oxide forming an 'in situ' nitrate ion.

  1. New infrared spectroscopic database for chlorine nitrate

    International Nuclear Information System (INIS)

    Fourier transform infrared measurements of chlorine nitrate have been performed in the spectral region 500-1330 cm-1 at 0.002-0.008 cm-1 spectral resolution. Absorption cross sections were derived from 23 spectra covering the temperature range from 190 to 296 K and air pressure range from 0 to 150 hPa. For line-by-line analysis, further spectra were recorded at 0.00094 cm-1 spectral resolution at 190 and 296 K. The sample was synthesized from N2O5 and Cl2O. Number densities in the absorption cell were derived from pressure measurements of the purified sample. Quality assurance included measurements with different sample pressures, spectroscopic purity check of the sample, comparison of integrated absorption cross sections over entire band systems, and assessment of residuals from remote-sensing retrievals. Multiplicative and additive errors were considered giving an overall uncertainty of +2.5/-3.5%. Further data reduction was achieved with an interpolation scheme based on two-dimensional polynomials in ln(pressure) and temperature. The worst-case error for the interpolated data is +4.5/-5.5%. The database is well-suited for remote-sensing application and should reduce the atmospheric chlorine nitrate error budget substantially

  2. Cement encapsulation of uranyl nitrate waste

    International Nuclear Information System (INIS)

    During decontamination of the former nuclear fuel reprocessing plant at West Valley, New York, low-level radioactive waste streams are being identified which require disposal in an environmentally acceptable manner. One such waste stream, consisting essentially of uranyl nitrate, has been located in one of the processing cells. A study was conducted on this waste stream to determine if it could be stably encapsulated in cement. First, a recipe was developed for cement-encapsulating this highly acidic waste. Samples were then made to perform waste qualification testing as described in the NRC Branch Technical Position-Waste Form to determine the stability of this waste form. The testing showed that the waste form had a compressive strength much greater than the 345 kPA (50 psi) minimum guideline after room-temperature cure, irradiation, thermal cycling, immersion, and biodegradation. In addition, the encapsulated waste had uranium and cerium leachability index values greater than six, which is the minimum recommended by the NRC position paper. The cement-encapsulated uranyl nitrate waste thus met the NRC stability guidelines for the disposal of Class B and Class C radioactive wastes

  3. Does the evidence about health risks associated with nitrate ingestion warrant an increase of the nitrate standard for drinking water?

    OpenAIRE

    Benjamin Nigel; Ward Mary H; van Grinsven Hans JM; de Kok Theo M

    2006-01-01

    Abstract Several authors have suggested that it is safe to raise the health standard for nitrate in drinking water, and save money on measures associated with nitrate pollution of drinking water resources. The major argument has been that the epidemiologic evidence for acute and chronic health effects related to drinking water nitrate at concentrations near the health standard is inconclusive. With respect to the chronic effects, the argument was motivated by the absence of evidence for adver...

  4. Nitrate concentrations in drainage water in marine clay areas : exploratory research of the causes of increased nitrate concentrations

    OpenAIRE

    Boekel, van, M.A.J.S.; Roelsma, J.; Massop, H.T.L.; R. F. A. Hendriks; Goedhart, P.W.; Jansen, P.C.

    2013-01-01

    The nitrate concentrations measured in drainage water and groundwater at LMM farms (farms participating in the National Manure Policy Effects Measurement Network (LLM)) in marine clay areas have decreased with 50% since the mid-nineties. The nitrate concentrations in marine clay areas are on average below 50 mg/L EU target value. A geographical analysis of the monitoring results shows, however, that the nitrate concentrations in 22% of the measurements, mainly taken in the south-western and c...

  5. Does the evidence about health risks associated with nitrate ingestion warrant an increase of the nitrate standard for drinking water?

    Directory of Open Access Journals (Sweden)

    Benjamin Nigel

    2006-09-01

    Full Text Available Abstract Several authors have suggested that it is safe to raise the health standard for nitrate in drinking water, and save money on measures associated with nitrate pollution of drinking water resources. The major argument has been that the epidemiologic evidence for acute and chronic health effects related to drinking water nitrate at concentrations near the health standard is inconclusive. With respect to the chronic effects, the argument was motivated by the absence of evidence for adverse health effects related to ingestion of nitrate from dietary sources. An interdisciplinary discussion of these arguments led to three important observations. First, there have been only a few well-designed epidemiologic studies that evaluated ingestion of nitrate in drinking water and risk of specific cancers or adverse reproductive outcomes among potentially susceptible subgroups likely to have elevated endogenous nitrosation. Positive associations have been observed for some but not all health outcomes evaluated. Second, the epidemiologic studies of cancer do not support an association between ingestion of dietary nitrate (vegetables and an increased risk of cancer, because intake of dietary nitrate is associated with intake of antioxidants and other beneficial phytochemicals. Third, 2–3 % of the population in Western Europe and the US could be exposed to nitrate levels in drinking water exceeding the WHO standard of 50 mg/l nitrate, particularly those living in rural areas. The health losses due to this exposure cannot be estimated. Therefore, we conclude that it is not possible to weigh the costs and benefits from changing the nitrate standard for drinking water and groundwater resources by considering the potential consequences for human health and by considering the potential savings due to reduced costs for nitrate removal and prevention of nitrate pollution.

  6. Influence of Carbon Source on Nitrate Removal by Nitrate-Tolerant Klebsiella oxytoca CECT 4460 in Batch and Chemostat Cultures

    OpenAIRE

    Piñar, Guadalupe; Kovárová, Karin; Egli, Thomas; Ramos, Juan L.

    1998-01-01

    The nitrate-tolerant organism Klebsiella oxytoca CECT 4460 tolerates nitrate at concentrations up to 1 M and is used to treat wastewater with high nitrate loads in industrial wastewater treatment plants. We studied the influence of the C source (glycerol or sucrose or both) on the growth rate and the efficiency of nitrate removal under laboratory conditions. With sucrose as the sole C source the maximum specific growth rate was 0.3 h−1, whereas with glycerol it was 0.45 h−1. In batch cultures...

  7. Heat transfer behavior of molten nitrate salt

    Science.gov (United States)

    Das, Apurba K.; Clark, Michael M.; Teigen, Bard C.; Fiveland, Woodrow A.; Anderson, Mark H.

    2016-05-01

    The usage of molten nitrate salt as heat transfer fluid and thermal storage medium decouples the generation of electricity from the variable nature of the solar resource, allowing CSP plants to avoid curtailment and match production with demand. This however brings some unique challenges for the design of the molten salt central receiver (MSCR). An aspect critical to the use of molten nitrate (60wt%/40wt% - NaNO3/KNO3) salt as heat transfer fluid in the MSCR is to understand its heat transfer behavior. Alstom collaborated with the University of Wisconsin to conduct a series of experiments and experimentally determined the heat transfer coefficients of molten nitrate salt up to high Reynolds number (Re > 2.0E5) and heat flux (q″ > 1000 kW/m2), conditions heretofore not reported in the literature. A cartridge heater instrumented with thermocouples was installed inside a stainless steel pipe to form an annular test section. The test section was installed in the molten salt flow loop at the University of Wisconsin facility, and operated over a range of test conditions to determine heat transfer data that covered the expected operating regime of a practical molten salt receiver. Heat transfer data were compared to widely accepted correlations found in heat transfer literature, including that of Gnielinski. At lower Reynolds number conditions, the results from this work concurred with the molten salt heat transfer data reported in literature and followed the aforementioned correlations. However, in the region of interest for practical receiver design, the correlations did not accurately model the experimentally determined heat transfer data. Two major effects were observed: (i) all other factors remaining constant, the Nusselt numbers gradually plateaued at higher Reynolds number; and (ii) at higher Reynolds number a positive interaction of heat flux on Nusselt number was noted. These effects are definitely not modeled by the existing correlations. In this paper a new

  8. Distribution and Sources of Nitrate-Nitrogen in Kansas Groundwater

    Directory of Open Access Journals (Sweden)

    Margaret A. Townsend

    2001-01-01

    Full Text Available Kansas is primarily an agricultural state. Irrigation water and fertilizer use data show long- term increasing trends. Similarly, nitrate-N concentrations in groundwater show long-term increases and exceed the drinking-water standard of 10 mg/l in many areas. A statistical analysis of nitrate-N data collected for local and regional studies in Kansas from 1990 to 1998 (747 samples found significant relationships between nitrate-N concentration with depth, age, and geographic location of wells. Sources of nitrate-N have been identified for 297 water samples by using nitrogen stable isotopes. Of these samples, 48% showed fertilizer sources (+2 to +8 and 34% showed either animal waste sources (+10 to +15 with nitrate-N greater than 10 mg/l or indication that enrichment processes had occurred (+10 or above with variable nitrate-N or both. Ultimate sources for nitrate include nonpoint sources associated with past farming and fertilization practices, and point sources such as animal feed lots, septic systems, and commercial fertilizer storage units. Detection of nitrate from various sources in aquifers of different depths in geographically varied areas of the state indicates that nonpoint and point sources currently impact and will continue to impact groundwater under current land uses.

  9. Characterization of the winter midwestern particulate nitrate bulge.

    Science.gov (United States)

    Pitchford, Marc L; Poirot, Richard L; Schichtel, Bret A; Maim, William C

    2009-09-01

    A previously unobserved multi-state region of elevated particulate nitrate concentration was detected as a result of the expansion of the Interagency Monitoring of Protected Visual Environments (IMPROVE) network of remote-area particulate matter (PM) speciation monitoring sites into the midwestern United States that began in 2002. Mean winter ammonium nitrate concentrations exceed 4 microg/m3 in a region centered in Iowa, which makes it responsible for as much as half of the particle light extinction. Before these observations, particulate nitrate in the United States was only observed to be a dominant component of the fine PM (PM2.5) in parts of California and some urban areas. Comparisons of the spatial patterns of particulate nitrate with spatial patterns of ammonia and nitrogen oxide emissions suggest that the nitrate bulge is the result of the high emissions of ammonia associated with animal agriculture in the Midwest. Nitrate episodes at several locations in the eastern United States are shown to be associated with transport pathways over the Midwest, suggesting long-range transport of either ammonia or ammonium nitrate. Thermodynamic equilibrium modeling conducted by others on data from the Midwest shows the relative importance of atmospheric ammonia and nitric acid in the production of PM2.5. This is a particular concern as the sulfur dioxide emissions in the United States are reduced, which increases the amount of ammonia available for ammonium nitrate production. PMID:19785273

  10. Evaluation of nitrate and nitrite destruction/separation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.T.

    1997-08-29

    This report describes and evaluates four types of nitrate and nitrite destruction and separation technologies that could be used to treat the aqueous, alkaline, nitrate-bearing mixed waste that is generated by the In-Tank Precipitation (ITP) process at the Savannah River Site (SRS). The technologies considered in this report include thermal, hydrothermal, chemical, and electrochemical technologies.

  11. Nitrate leaching and pesticide use in energy crops

    DEFF Research Database (Denmark)

    Jørgensen, Uffe

    2006-01-01

    Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well.......Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well....

  12. Predicting SOA from organic nitrates in the southeastern United States

    Science.gov (United States)

    Organic nitrates have been identified as an important component of ambient aerosol in the Southeast United States. In this work, we use the Community Multiscale Air Quality (CMAQ) model to explore the relationship between gas-phase production of organic nitrates and their subsequ...

  13. Densities concentrations of aqueous of uranyl nitrate solutions

    International Nuclear Information System (INIS)

    The ratio density-concentration of aqueous uranyl nitrate solutions expressed as U3O8 grams/liter, U grams/liter and hexahydrate uranyl nitrate weight percent at different temperatures, are established. Experimental values are graphically correlated and compared whit some published data. (Author) 2 refs

  14. Nitrate decontamination through functionalized chitosan in brackish water.

    Science.gov (United States)

    Appunni, Sowmya; Rajesh, Mathur P; Prabhakar, Sivaraman

    2016-08-20

    N, N, N-Triethyl ammonium functionalized cross-linked chitosan beads (TEACCB) was prepared by alkylation of glutaraldehyde cross-linked chitosan beads to remove nitrate from brackish water. Physico-chemical characteristics of TEACCB were analyzed using FTIR, SEM, EDAX, TGA, DTA, BET surface area, swelling ratio and pHzpc. The maximum nitrate removal capacity of TEACCB was 2.26meq/g and is higher than other reported chitosan based adsorbents. Nitrate removal ratio in the presence and absence of common anions like chloride and sulphate demonstrated the selectively of TEACCB towards nitrate. The kinetic data of nitrate removal fitted well with the pseudo-second-order kinetic model. The thermodynamic parameters indicated that nitrate removal could be spontaneous and exothermic in nature. TEACCB was reused with 100% efficiency after regenerating with 0.05N HCl. Column study was carried out to remove nitrate from brackish water. These results are very significant to develop TEACCB based nitrate removal technology with great efficiency. PMID:27178960

  15. Removal of Nitrate From Aqueous Solution Using Rice Chaff

    Directory of Open Access Journals (Sweden)

    Dehghani

    2015-09-01

    Full Text Available Background Nitrate is largely dissolved in the surface and ground water, due to its high solubility. Continual uptake of nitrite through drinking water can lead to problems and diseases (such as blue baby for humans, especially children. Objectives The aim of this study was to develop a new and inexpensive method for the removal of nitrate from water. In this regard, the possibility of using chaff for removal of nitrate from aqueous solutions was studied and the optimum operating conditions of nitrate removal was determined. Materials and Methods This is a cross-sectional study conducted in laboratory scale. The UV spectrophotometer at a wavelength of maximum absorbance (220 nm was used to determine the nitrate concentration. The effect of pH, amount of chaff, temperature, and contact time were investigated. Results The result of this study revealed that chaff as an absorbent could remove nitrate from solutions, and the efficiency of adsorption increased as contact time increased from 5 to 30 minutes, amount of chaff increased from 1 to 3 g, temperature increased in a range of 300 - 400°C and the amount of pH decreased from 10 to 3. The maximum adsorption rate was around pH 3 (53.14%. Conclusions It was shown that the removal efficiency of nitrate was directly proportional to the amount of chaff, temperature, and contact time but inversely to the pH. This study showed that nitrate removal by chaff is a promising technique.

  16. NITRITE AND NITRATE DETERMINATIONS IN PLASMA - A CRITICAL-EVALUATION

    NARCIS (Netherlands)

    MOSHAGE, H; KOK, B; HUIZENGA, [No Value; JANSEN, PLM

    1995-01-01

    Plasma nitrite and nitrate determinations are increasingly being used in clinical chemistry as markers for the activity of nitric oxide synthase and the production of nitric oxide radicals. However, a systematic evaluation of the determination of nitrite and nitrate in plasma has not been performed.

  17. Effects of sludge disposal on groundwater nitrate concentrations

    Science.gov (United States)

    Spalding, R. F.; Exner, M. E.; Martin, G. E.; Snow, D. D.

    1993-02-01

    More than 100 groundwater samples were collectd and analyzed for nitrate-nitrogen, δ 15N of the nitrate, dissolved organic carbon (DOC), and chloride. Multilevel samplers and nested monitoring wells were located beneath and down-gradient from an irrigated cornfield on which human waste sludge was injected. The sampling delineated a 1.3km× 0.3km plume of nitrate contamination. Both the nitrate-nitrogen concentrations and the δ 15N values within the plume's centroid were homogeneous. The levels were 34 ± 3mg1 -1 and + 13.4 ± 1.2%, respectively. A retarding zone of clayey silt split the plume and separated the oxic water from the deeper anoxic water. Nitrate levels were lower in the anoxic water and declined rapidly with depth. The significant association ( r = - 0.91) between increasing δ 15N values and decreasing nitrate concentrations indicated that the nitrate was denitrified. High chloride concentrations in the anoxic zone beneath the retarding layer are thought to originate from the sludge storage lagoon and/or the sludge compost piles. Tritium and atrazine levels confirm that this is recent recharge water. Denitrification has utilized most of the original nitrate and DOC in the plume.

  18. CU(II): catalyzed hydrazine reduction of ferric nitrate

    International Nuclear Information System (INIS)

    A method is described for producing ferrous nitrate solutions by the cupric ion-catalyzed reduction of ferric nitrate with hydrazine. The reaction is complete in about 1.5 hours at 400C. Hydrazoic acid is also produced in substantial quantities as a reaction byproduct

  19. Spatial assessment of animal manure spreading and groundwater nitrate pollution

    Directory of Open Access Journals (Sweden)

    Roberta Infascelli

    2009-11-01

    Full Text Available Nitrate concentration in groundwater has frequently been linked to non-point pollution. At the same time the existence of intensive agriculture and extremely intensive livestock activity increases the potential for nitrate pollution in shallow groundwater. Nitrate used in agriculture could cause adverse effects on human and animal health. In order to evaluate the groundwater nitrate pollution, and how it might evolve in time, it is essential to develop control systems and to improve policies and incentives aimed at controlling the amount of nitrate entering downstream water systems. The province of Caserta in southern Italy is characterized by high levels of animal manure loading. A comparison between manure nitrogen production and nitrate concentration in groundwater was carried out in this area, using geostatistical tools and spatial statistics. The results show a discrepancy between modelling of nitrate leaching and monitoring of the groundwater and, moreover, no spatial correlation between nitrogen production in livestock farms and nitrate concentration in groundwater, suggesting that producers are not following the regulatory procedures for the agronomic use of manure. The methodology developed in this paper could be applied also in other regions in which European Union fertilization plans are not adequately followed.

  20. Nitration of the tyrosine residues of porcine pancreatic colipase with tetranitromethane, and properties of the nitrated derivatives.

    Science.gov (United States)

    De Caro, J D; Behnke, W D; Bonicel, J J; Desnuelle, P A; Rovery, M

    1983-09-28

    The nitration of the long form (N-terminal valine) of porcine pancreatic colipase with tetranitromethane was investigated under a variety of conditions. Fractionation of the nitrated monomers on DE-cellulose led to well-defined derivatives containing one, two and three nitrotyrosines per mol. Automated Edman degradation of the nitrated peptides, especially that of the staphylococcal proteinase peptide (49-64) showed that Tyr-54 was nitrated very fast under all conditions. This residue was the only one to be nitrated in water. Partial nitration of Tyr-59 was induced by bile salt micelles, while both Tyr-59 and Tyr-58 reacted extensively in the presence of lysophosphatidylcholine micelles (in which tetranitromethane is concentrated 150-fold compared to water) or of a liquid tetranitromethane-water interface. The strong negative Cotton effect at 410 nm which has already been observed using unfractionated preparations of nitrated colipase (Behnke W.D. (1982) Biochim. Biophys. Acta 708, 118-123) is linked with the nitration of Tyr-59 and it is markedly reduced by taurodeoxycholate micelles, suggesting a conformational change induced by the micelles in the tyrosine region. Moreover, the pKa of the nitrotyrosine residues in nitrated colipase is the same as that of free nitrotyrosine (pKa = 6.8) and it is shifted to 7.6 in the presence of taurodeoxycholate micelles. Micelles protected colipase against polymerization during nitration. These data suggest that Tyr-58 and Tyr-59 are part of the interface recognition site of colipase. The participation of Tyr-55 in binding is not excluded. The upwards nitrotyrosine pKa shift in the colipase micelle complex may explain why nitrated colipase can reactivate lipase in a triacylglycerol-taurodeoxycholate system at pH 7.5. PMID:6615844

  1. X-ray irradiation induced degradation of cellulose nitrate

    International Nuclear Information System (INIS)

    Energy-dispersive X-ray fluorescence (EDXRF) spectrometry was previously proposed to measure the thickness of the cellulose nitrate layer of the commonly used LR 115 solid-state nuclear track detector (SSNTD). The present work is devoted to the investigation whether the X-ray radiation involved in EDXRF spectrometry will induce degradation of the cellulose nitrate. For this purpose, Fourier transform infrared (FTIR) spectroscopy was employed to examine the nitrate functions (at the wavenumber 1598 cm-1) and the glycosidic bonds (at 1146 cm-1) for various irradiation time involved in the EDXRF spectrometry. No significant changes were observed even for X-ray irradiation up to 3000 live seconds, which was equivalent for 10 separate scans and should be far more than enough for a determination of the cellulose nitrate layer thickness. Therefore, EDXRF remains a fast and non-destructive method to measure the active layer thickness of the cellulose nitrate SSNTD

  2. Electrochemical processing of alkaline nitrate and nitrite wastes

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce, as a by-product, a low-level, alkaline salt solution containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement formulation, saltstone, and placed in an engineered landfill. Electrochemical methods have been investigated to decrease the nitrate and nitrite in this solution in order to lower the leaching of nitrate and nitrite from saltstone and to reduce the volume of saltstone. Laboratory experiments have demonstrated the technical feasibility of electrolytically reducing the nitrate and nitrite in a synthetic salt solution similar in composition to that expected to be produced at SRP. Greater than 99% of the sodium nitrate and sodium nitrite can be reduced, producing ammonia, nitrogen, oxygen, and sodium hydroxide. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  3. Method of processing nitrate-containing radioactive liquid wastes

    International Nuclear Information System (INIS)

    Purpose: To efficiently concentrate nitrate-containing low level radioactive liquid wastes by electrolytically dialyzing radioactive liquid wastes to decompose the nitrate salt by using an electrolytic cell comprising three chambers having ion exchange membranes and anodes made of special materials. Method: Nitrate-containing low level radioactive liquid wastes are supplied to and electrolytically dialyzed in a central chamber of an electrolytic cell comprising three chambers having cationic exchange membranes and anionic exchange membranes made of flouro-polymer as partition membranes, whereby the nitrate is decomposed to form nitric acid in the anode chamber and alkali hydroxide compound or ammonium hydroxide in the cathode chamber, as well as concentrate the radioactive substance in the central chamber. Coated metals of at least one type of platinum metal is used as the anode for the electrolytic cell. This enables efficient industrial concentration of nitrate-containing low level radioactive liquid wastes. (Yoshihara, H.)

  4. Assessment of nitrate export from a high elevation watershed

    International Nuclear Information System (INIS)

    Nitrate leaching from forest soils can be detrimental to both the forest ecosystems and stream water quality. Nitrate moving through the soil transports plant nutrients and acidifying agents, hydrogen and aluminum, and can export them to streams. In the high elevation spruce-fir forests in the Great Smoky Mountains National Park (GRSM) nitrate has been found to be leaching from the rooting zone. Streams associated with these ecosystems are poorly buffered. Therefore rapid export of nitrate from the soils to the streams could lead to episodic acidification. The purpose of the Noland Divide watershed study is to assess the levels of nitrate export from the watershed to the streams and the potential impacts of the export to the ecosystem

  5. Electrolytic denitrification of alkaline nitrate and nitrite solution

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce a low-level alkaline salt solution, containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement wasteform, saltstone, and placed in an engineered landfill. Laboratory experiments have demonstrated the technical feasibility of electrochemically reducing the nitrate and nitrite in a synthetic, nonradioactive salt solution similar in composition to that expected to be produced at SRP. Greater than ninety-five percent of the sodium nitrate and sodium nitrite can be reduced electrolytically, producing ammonia, nitrogen, oxygen, and sodium hydroxide. Reduction of the nitrate and nitrite will reduce the leaching of nitrate and nitrite from the saltstone monolith. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  6. Electrochemical processing of alkaline nitrate and nitrite solutions

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce, as a by product, a low- level, alkaline salt solution containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement formulation, saltstone, and placed in an engineered landfill. Electrochemical methods have been investigated to decrease the nitrate and nitrite in this solution in order to lower the leaching of nitrate and nitrite from saltstone and to reduce the volume of saltstone. Laboratory experiments have demonstrated the technical feasibility of electrolytically reducing the nitrate and nitrite in a synthetic salt solution similar in composition to that expected to be produced at SRP. Greater than 99% of the sodium nitrate and sodium nitrite can be reduced, producing ammonia, nitrogen, oxygen, and sodium hydroxide. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  7. Anoxic Activated Sludge Monitoring with Combined Nitrate and Titrimetric Measurements

    DEFF Research Database (Denmark)

    Petersen, B.; Gernaey, Krist; Vanrolleghem, P.A.

    2002-01-01

    An experimental procedure for anoxic activated sludge monitoring with combined nitrate and titrimetric measurements is proposed and evaluated successfully with two known carbon sources, (-)acetate and dextrose. For nitrate measurements an ion-selective nitrate electrode is applied to allow for...... frequent measurements, and thereby the possibility for detailed determination of the denitrification biokinetics. An internal nitrate electrode calibration is implemented in the experiments to avoid the often-encountered electrode drift problem. It was observed that the best experimental design was with...... the carbon source in excess, since excess nitrate provoked nitrite build-up thereby complicating the data interpretation. A conceptual model could quantitatively describe the experimental observations and thus link the experimentally measured proton production with the consumption of electron acceptor...

  8. Rovibronic Variational Calculations of the Nitrate Radical

    Science.gov (United States)

    Changala, Bryan; Baraban, Joshua H.; Stanton, John F.

    2015-06-01

    In recent years, sophisticated diabatic Hamiltonians have been developed in order to understand the low-energy vibronic level structure of the nitrate radical (NO_3), which exhibits strong coupling between the ~X and doubly degenerate ~B states. Previous studies have reproduced the observed vibronic level positions up to 2000 wn~above the zero-point level, yet the rotational structure has remained uninvestigated with ab initio methods. In this talk, we present calculations of the N≥0 rovibronic structure of low-lying vibronic states of NO_3, in which complicated rovibrational and Coriolis interactions have been observed. Our results include calculations using both adiabatic and diabatic Hamiltonians, enabling a direct comparison between the two. We discuss extensions of our treatment to include spin-orbit and spin-rotation effects.

  9. Nitrate reduction in geologically heterogeneous catchments

    DEFF Research Database (Denmark)

    Refsgaard, Jens Christian; Auken, Esben; Bamberg, Charlotte A.; Christensen, Britt Stenhøj Baun; Clausen, Thomas; Dalgaard, Esben; Effersø, Flemming; Ernstsen, Vibeke; Gertz, Flemming; Hansen, Anne Lausten; He, Xin; Jacobsen, Brian H.; Jensen, Karsten Høgh; Jørgensen, Flemming; Jørgensen, Lisbeth Flindt; Koch, Julian; Nilsson, Bertel; Petersen, Christian; De Schepper, Guillaume; Schamper, Cyril; Sørensen, Kurt I.; Therrien, Rene; Thirup, Christian; Viezzoli, Andrea

    zone is reduced in the saturated zone before reaching the streams, and vulnerable areas, where no subsurface reduction takes place, and then only impose regulations/restrictions on the vulnerable areas. Distributed hydrological models can make predictions at grid scale, i.e. at much smaller scale than...... the entire catchment. However, as distributed models often do not include local scale hydrogeological heterogeneities, they are typically not able to make accurate predictions at scales smaller than they are calibrated. We present a framework for assessing nitrate reduction in the subsurface and for...... assessing at which spatial scales modelling tools have predictive capabilities. A new instrument has been developed for airborne geophysical measurements, Mini-SkyTEM, dedicated to identifying geological structures and heterogeneities with horizontal and lateral resolutions of 30–50 m and 2 m, respectively...

  10. Thermal Decomposition of Nitrated Tributyl Phosphate

    International Nuclear Information System (INIS)

    Contact between tributyl phosphate and aqueous solutions of nitric acid and/or heavy metal nitrate salts at elevated temperatures can lead to exothermic reactions of explosive violence. Even though such operations have been routinely performed safely for decades as an intrinsic part of the Purex separation processes, several so-called ''red oil'' explosions are known to have occurred in the United States, Canada, and the former Soviet Union. The most recent red oil explosion occurred at the Tomsk-7 separations facility in Siberia, in April 1993. That explosion destroyed part of the unreinforced masonry walls of the canyon-type building in which the process was housed, and allowed the release of a significant quantity of radioactive material

  11. Removal of gadolinium nitrate from heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.

    2000-03-22

    Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

  12. Hydrogels made from chitosan and silver nitrate.

    Science.gov (United States)

    Kozicki, Marek; Kołodziejczyk, Marek; Szynkowska, Małgorzata; Pawlaczyk, Aleksandra; Leśniewska, Ewa; Matusiak, Aleksandra; Adamus, Agnieszka; Karolczak, Aleksandra

    2016-04-20

    This work describes a gelation of chitosan solution with silver nitrate. Above the critical concentration of chitosan (c*), continuous hydrogels of chitosan-silver can be formed. At lower concentrations, the formation of nano- and micro-hydrogels is discussed. The sol-gel analysis was performed to characterise the hydrogels' swelling properties. Moreover, the following were employed: (i) mechanical testing of hydrogels, (ii) inductively coupled plasma-optical emission spectroscopy (ICP-OES) for the measurement of silver concentration, (iii) scanning electron microscopy (SEM) to examine the morphology of products obtained, and (iv) dynamic light scattering (DLS) and UV-vis spectrophotometry to examine products formed at low concentration of chitosan (c

  13. Registration probability of alphas in cellulose nitrate

    International Nuclear Information System (INIS)

    Registration 'thresholds' of alpha particles in cellulose nitrate plastic present a statistical behaviour. The effect depends on etching conditions. It is particularly large in strong etching conditions, in which registration is transposed to high energies: up to 7.7 MeV for the conditions and energies studied. 'Registration probability' expresses more adequately the effect of registration constraints. The study of registration probability indicates that the 'target theory' can describe the effect. The parameters of target theory, m (number of targets) and D0 (the equivalent of biological dose D37) were found to be: m = 5 and D0 = 3 x 107 erg cm-3. Dose distribution around the trajectory of alphas of various energies is estimated. It is also deduced that track development takes place when the required dose for registration is deposited at a distance r >= 20 A from particle trajectory. (author)

  14. Green and controllable metal-free nitrification and nitration of arylboronic acids

    Institute of Scientific and Technical Information of China (English)

    Shuai Wang; Chun Chun Shu; Tao Wang; Jian Yu; Guo Bing Yan

    2012-01-01

    A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids,which can be controlled by the reaction conditions.The process provides an attractive alternative to the traditional nitration protocols.

  15. Water rotational jump driven large amplitude molecular motions of nitrate ions in aqueous potassium nitrate solution

    CERN Document Server

    Banerjee, Puja; Bagchi, Biman

    2016-01-01

    Molecular dynamics simulations of aqueous potassium nitrate solution reveal a highly complex rotational dynamics of nitrate ions where, superimposed on the expected continuous Brownian motion, are large amplitude angular jumps that are coupled to and at least partly driven by similar large amplitude jump motions in water molecules which are associated with change in the hydrogen bonded water molecule. These jumps contribute significantly to rotational and translational motions of these ions. We explore the detailed mechanism of these correlated (or, coupled) jumps and introduce a new time correlation function to decompose the coupled orientational- jump dynamics of solvent and solute in the aqueous electrolytic solution. Time correlation function provides for the unequivocal determination of the time constant involved in orientational dynamics originating from making and breaking of hydrogen bonds. We discover two distinct mechanisms-both are coupled to density fluctuation but are of different types.

  16. ARRAYS OF BOTTLES OF PLUTONIUM NITRATE SOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Margaret A. Marshall

    2012-09-01

    In October and November of 1981 thirteen approaches-to-critical were performed on a remote split table machine (RSTM) in the Critical Mass Laboratory of Pacific Northwest Laboratory (PNL) in Richland, Washington using planar arrays of polyethylene bottles filled with plutonium (Pu) nitrate solution. Arrays of up to sixteen bottles were used to measure the critical number of bottles and critical array spacing with a tight fitting Plexiglas® reflector on all sides of the arrays except the top. Some experiments used Plexiglas shells fitted around each bottles to determine the effect of moderation on criticality. Each bottle contained approximately 2.4 L of Pu(NO3)4 solution with a Pu content of 105 g Pu/L and a free acid molarity H+ of 5.1. The plutonium was of low 240Pu (2.9 wt.%) content. These experiments were sponsored by Rockwell Hanford Operations because of the lack of experimental data on the criticality of arrays of bottles of Pu solution such as might be found in storage and handling at the Purex Facility at Hanford. The results of these experiments were used “to provide benchmark data to validate calculational codes used in criticality safety assessments of [the] plant configurations” (Ref. 1). Data for this evaluation were collected from the published report (Ref. 1), the approach to critical logbook, the experimenter’s logbook, and communication with the primary experimenter, B. Michael Durst. Of the 13 experiments preformed 10 were evaluated. One of the experiments was not evaluated because it had been thrown out by the experimenter, one was not evaluated because it was a repeat of another experiment and the third was not evaluated because it reported the critical number of bottles as being greater than 25. Seven of the thirteen evaluated experiments were determined to be acceptable benchmark experiments. A similar experiment using uranyl nitrate was benchmarked as U233-SOL-THERM-014.

  17. Effects of mineral dust on global atmospheric nitrate concentrations

    Science.gov (United States)

    Karydis, V. A.; Tsimpidi, A. P.; Pozzer, A.; Astitha, M.; Lelieveld, J.

    2016-02-01

    This study assesses the chemical composition and global aerosol load of the major inorganic aerosol components, focusing on mineral dust and aerosol nitrate. The mineral dust aerosol components (i.e., Ca2+, Mg2+, K+, Na+) and their emissions are included in the ECHAM5/MESSy Atmospheric Chemistry model (EMAC). Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model that considers K+, Ca2+, Mg2+, NH4+, Na+, SO42-, NO3-, Cl-, and H2O aerosol components. Emissions of mineral dust are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. Presence of metallic ions can substantially affect the nitrate partitioning into the aerosol phase due to thermodynamic interactions. The model simulates highest fine aerosol nitrate concentration over urban and industrialized areas (1-3 µg m-3), while coarse aerosol nitrate is highest close to deserts (1-4 µg m-3). The influence of mineral dust on nitrate formation extends across southern Europe, western USA, and northeastern China. The tropospheric burden of aerosol nitrate increases by 44 % when considering interactions of nitrate with mineral dust. The calculated global average nitrate aerosol concentration near the surface increases by 36 %, while the coarse- and fine-mode concentrations of nitrate increase by 53 and 21 %, respectively. Other inorganic aerosol components are affected by reactive dust components as well (e.g., the tropospheric burden of chloride increases by 9 %, ammonium decreases by 41 %, and sulfate increases by 7 %). Sensitivity tests show that nitrate aerosol is most sensitive to the chemical composition of the emitted mineral dust, followed by the soil size distribution of dust particles, the magnitude of the mineral dust emissions, and the aerosol state assumption.

  18. The oral bioavailability of nitrate from vegetables investigated in healthy volunteers

    OpenAIRE

    Lambers AC; Kortboyer JM; Schothorst RC; Sips AJAM; Cleven RFMJ; Meulenbelt J; VIC; LBM; ARO; LAC

    2000-01-01

    The major source of human nitrate exposure comes from vegetables. Several studies were performed to estimate the total daily dietary nitrate intake based on the nitrate contents of food and drinking water. However, only nitrate that is absorbed from the gastro-intestinal tract may contribute to the toxicity of nitrate in the body. At present no data are available on the bioavailability of nitrate from vegetables. Therefore the present study was performed to evaluate the oral bioavailability o...

  19. Effects of Amino Acids Replacing Nitrate on Growth, Nitrate Accumulation, and Macroelement Concentrations in Pak-choi (Brassica chinensis L.)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen (N), phosphorus (P), and potassium (K) in pak-choi (Brassica chinensis L.) shoots. When 20% of nitrate-N was replaced with arginine (Arg)compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly (P ≤ 0.05), but when 20% of nitrate-N was replaced with alanine (Ala), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), phenylalanine (Phe), methionine (Met), aspartic acid (Asp), glutamic acid (Glu), lysine (Lys), glycine (Gly), serine (Ser), threonine(Thr), cysteine (Cys), and tyrosine (Tyr), shoot fresh and dry weights decreased significantly (P ≤ 0.05). After replacing 20% of nitrate-N with asparagine (Asn) and glutamine (Gln), shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine (His), and Arg, significantly reduced (P ≤ 0.05) nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased (P ≤ 0.05). Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.

  20. Nitrate concentrations in soil solutions below Danish forests

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Raulund-Rasmussen, Karsten; Gundersen, Per;

    1999-01-01

    Nitrate in the soil water below the root zone is a pre-condition for nitrate leaching, and it indicates loss of nutrients from the forest ecosystem. Nitrate leaching may potentially cause eutrophication of surface water and contamination of ground water. In order to evaluate the extent of nitrate...... leaching in relation to land-use, a national monitoring programme has established sampling routines in a 7x7 km grid including 111 points in forests. During winters of 1986-1993, soil samples were obtained from a depth of 0-25, 25-50, 50-75 and 75-100 cm. Nitrate concentrations in soil solutions were...... determined by means of a 1 M KCl extraction. The influence of forest size, forest-type, soil-type, tree species and sampling time on the nitrate concentrations was analysed in a statistical model. The analysis focused on data from depth 75-100 cm, as nitrate is considered potentially lost from the ecosystem...

  1. Waste generation reduction: nitrates. FY 1984 status report

    International Nuclear Information System (INIS)

    A study was initiated at Rocky Flats Plant (RFP) to develop and demonstrate technology to eliminate nitrates in low-level waste streams without generating objectionable oxides of nitrogen. Various chemical and thermal methods of denitrification were investigated earlier in this program. Work in FY 1984 was conducted on the Thagard High Temperature Fluid Wall Reactor (HTFWR) and on an aqueous two-step process. Preliminary tests were conducted on a plasma torch system. Testing was completed with actual RFP nitrate wastes on an aqueous process consisting of formic and sulfuric acid reflux, followed by evaporation of the liquid to dryness. Results from this process show promising nitrate destruction, but with production of some NO/sub x/ in the off-gas. Also completed in aqueous testing were laser excitation techniques, indicating that the high activation energy of the nitrate ion can be overcome with a simpler chemical reaction with additional energy applied. Experiments were conducted using an HTFWR to determine its nitrate/nitrite destruction efficiency on simulated RFP and Savannah River Plant waste streams. These streams included nitrate-contaminated soils and feeds containing surrogate fission products. Various additives were tested to enhance nitrate destruction, reduce NO/sub x/ off-gas generation, and produce an acceptable final waste form

  2. Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry

    Directory of Open Access Journals (Sweden)

    A. L. Lockwood

    2010-07-01

    Full Text Available Isoprene is an important atmospheric volatile organic compound involved in ozone production and NOx (NO+NO2 sequestration and transport. Isoprene reaction with OH in the presence of NO can form either isoprene hydroxy nitrates ("isoprene nitrates" or convert NO to NO2 which can photolyze to form ozone. While it has been shown that isoprene nitrate production can represent an important sink for NOx in forest impacted environments, there is little experimental knowledge of the relative importance of the individual isoprene nitrate isomers, each of which has a different fate and reactivity. In this work, we have identified the 8 individual isomers and determined their total and individual production yields. The overall yield of isoprene nitrates at atmospheric pressure and 295 K was found to be 0.070(+0.025/−0.015. Three isomers, representing nitrates resulting from OH addition to a terminal carbon, represent 90% of the total IN yield. We also determined the ozone rate constants for three of the isomers, and have calculated their atmospheric lifetimes, which range from ~1–2 h, making their oxidation products likely more important as atmospheric organic nitrates and sinks for nitrogen.

  3. Implementation of the eu nitrates directive in Turkey

    Directory of Open Access Journals (Sweden)

    Hatice BİLGİN YILDIRIM

    2012-06-01

    Full Text Available The EU Nitrates Directive is of a prime importance in respect of sustaining the natural resources for the reduction and prevention of nitrate pollution resulting from agricultural activities, and it constitutes an integral part of the EU Water Framework Directive. Accepted by the European Council in 1991, the directive entered into force being published in Official Gazette in 2004 in Turkey as “Regulation on the Protection of Waters against Pollution Caused by Nitrates from Agricultural Sources.” As of this date, works on harmonization have been intensely continued. The works brought together multiple organizations that are notable in terms of waterworks and ensured informatory exchange through the contributions of the EU member states. Approaching to the finalization of its harmonization process, Turkey will proclaim its country either a “border to border nitrate-sensitive zone” or “nitrate vulnerable zone” in order to issue the secondary legislations required by the Nitrates Directive in accordance with these approaches. This paper covers the current works conducted with regard to the implementation of the Nitrates Directive and it has been prepared aiming at inviting attentions to the current and possible complications in the implementation process.

  4. Sources of Nitrate Contamination in Groundwater Under Developing Asian Megacities

    Science.gov (United States)

    Umezawa, Y.; Hosono, T.; Onodera, S.; Siringan, F.; Buapeng, S.; Delinom, R. M.; Yoshimizu, C.; Tayasu, I.; Nagata, T.; Taniguchi, M.

    2008-12-01

    The status of nitrate, nitrite and ammonium contamination in the water systems, and the mechanisms controlling their sources, pathways, and distributions were investigated for the Southeast Asian cities of Metro Manila, Bangkok, and Jakarta. GIS-based monitoring and dual isotope approach (nitrate d15N and d18O) suggested that human waste via severe sewer leakage was the major source of nutrient contaminants in Metro Manila and Jakarta urban areas. Furthermore, the characteristics of the nutrient contamination differed depending on the agricultural land use pattern in the suburban areas. The exponential increase in nitrate d15N along with the nitrate reduction and clear d18O/d15N slopes of nitrate (~0.5) indicated the occurrence of denitrification. An anoxic subsurface system associated with the natural geological setting (e.g., the old tidal plain at Bangkok) and artificial pavement coverage served to buffer nitrate contamination via active denitrification and reduced nitrification. Our results showed that nitrate and ammonium contamination of the aquifers in Metro Manila, Bangkok, and Jakarta was not excessive, suggesting low risk of drinking groundwater to human health, at present. However, the increased nitrogen load and increased per capita gross domestic product (GDP) in these developing cities may increase this contamination in the very near future. Continuous monitoring and management of the groundwater system is needed to minimize groundwater pollution in these areas.

  5. Nitrate contamination of groundwater: A conceptual management framework

    International Nuclear Information System (INIS)

    In many countries, public concern over the deterioration of groundwater quality from nitrate contamination has grown significantly in recent years. This concern has focused increasingly on anthropogenic sources as the potential cause of the problem. Evidence indicates that the nitrate (NO3) levels routinely exceed the maximum contaminant level (MCL) of 10 mg/l NO3-N in many aquifer systems that underlie agriculture-dominated watersheds. Degradation of groundwater quality due to nitrate pollution along with the increasing demand for potable water has motivated the adoption of restoration actions of the contaminated aquifers. Restoration efforts have intensified the dire need for developing protection alternatives and management options such that the ultimate nitrate concentrations at the critical receptors are below the MCL. This paper presents a general conceptual framework for the management of groundwater contamination from nitrate. The management framework utilizes models of nitrate fate and transport in the unsaturated and saturated zones to simulate nitrate concentration at the critical receptors. To study the impact of different management options considering both environmental and economic aspects, the proposed framework incorporates a component of a multi-criteria decision analysis. To enhance spatiality in model development along with the management options, the utilization of a land use map is depicted for the allocation and computation of on-ground nitrogen loadings from the different sources

  6. NITRATE AND NITRITE CONCENTRATION IN VEGETABLES GRAWING AROUND ISFAHAN CITY

    Directory of Open Access Journals (Sweden)

    R.A JAFARI

    2001-06-01

    Full Text Available Introduction: The improper and excess use of chemical fertilizers by the farmers special in "urea" form may cause the commulation of nitrates and nitrites in vegetables and fruits. This investigation has been done to determine the concentration of nitrates and nitrites in some vegetables growing around Isfahan. Methods: One hundred and thirteen random samples from 15 different kinds of green lest tuber vegetables were measured by Cadmium Column Procedure for nitrates and nitrites. Results: The mean of the nitrates level in green leaf and tuber-vegetables was 287.9 and 76.3 mg/kg, respectively. These amounts were more higher than standard value (67 mg/kg in the basis of wet material, significantly. The mean of the nitrite level in green leaf and tuber vegetables were 1.7 and 1 mg/kg, repectively, which were more higher than standard value (zero mg/kg in the basis of wet matrial. The most high concentration of nitrites and nitrates was seen in commondill and leek, repectively. Discussion: Amounts of nitrites and nitrates in our analysed samples exceeded the perimissible limits. The comulation of nitrates in some of the vegetables depend on the application of chemical fertilizers, temprature and wether, but the nitrites in vegetables is unusual in normal condition and the unsuitable storage of them causes it"s expansion.

  7. Biological denitrification of high sodium nitrate bearing actual reprocessing waste

    International Nuclear Information System (INIS)

    High nitrate bearing alkaline waste solution of reprocessing plant origin was decontaminated by adopting an ion exchange followed by a chemical treatment based process. The resulting effluent was then subjected to nitrate removal by biodenitrification. A flow through bioreactor provided with stainless steel modules as support for biomass growth was setup and the biomass in reactor was acclimatized to a NaNO3 solution of concentration level comparable to actual effluents. The bioreactor was used for denitrification of the actual effluent in continuous mode and complete denitrification of the actual reprocessing waste solution containing 17,500 ppm of nitrate has been successfully demonstrated. (author)

  8. Electrolytic Removal of Nitrate From CELSS Crop Residues

    Science.gov (United States)

    Colon, Guillermo; Sager, John

    1996-01-01

    The controlled ecological life support system (CELSS) resource recovery system is a waste processing system using aerobic and anaerobic bioreactors to recover plant nutrients and secondary foods from inedible biomass. Crop residues contain significant amounts of nitrate which presents two problems: (1) both CELSS biomass production and resource recovery consume large quantities of nitric acid, (2) nitrate causes a variety of problems in both aerobic and anaerobic bioreactors. A technique was proposed to remove the nitrate from potato inedible biomass leachate and to satisfy the nitric acid demand using a four compartment electrolytic cell.

  9. Effect of Ammonium Nitrate on Nanoparticle Size Reduction

    Directory of Open Access Journals (Sweden)

    Kalyana C. Pingali

    2008-01-01

    Full Text Available Ammonium nitrate was added to the spraying solution as a foaming agent to reduce the particle size of nanoparticles synthesized in the spray-pyrolysis process. Ammonium nitrate was effective in breaking the aerosol droplet size and generating nanoparticles that were of approximately one order-of-magnitude (from 200 to 20 nm smaller diameter than those created in the absence of ammonium nitrate in the feed solution. This technique makes it possible to control the particle diameter of metallic nanoparticles below 20 nm.

  10. Chemical denitration of aqueous nitrate solutions

    International Nuclear Information System (INIS)

    The Plant for Active Waste Liquids (PAWL) at CRNL will immobilize in glass the fission products in waste from Mo-99 production. The nitrate ions in the waste can be destroyed by heating, but also by chemical reaction with formic acid (HCOOH). Since chemical denitration has several advantages over thermal denitration it was studied in the course of vitrification process development. Two free radical mechanisms are examined here to explain kinetic data on chemical denitration of nitric acid solutions with formic acid. One mechanism is applicable at > 1 mol/L HNO3 and involves the formate radical (HCOO.). The second mechanism holds at 3 and involves the hyponitrous radical (HNO.). Mass balances for various species were written based on the law of mass action applied to the equations describing the reaction mechanism. Analytical and numerical solutions were obtained and compared. Literature data on batch denitration were used to determine some of the rate constants while others were set arbitrarily. Observed stoichiometry and trends in reactant concentrations are predicted accurately for batch data. There are no literature data to compare with the prediction of negligible induction time

  11. Reaction of lanthanide nitrates with macrocyclic amidoacylhydrazones

    Energy Technology Data Exchange (ETDEWEB)

    Malinka, E.V.; Bondarev, M.L.; Bel' tyukova, S.V.; Poleuktov, N.S.; Nazarenko, N.A.

    1987-09-01

    This paper deals with a study of the reaction of neodymium and europium nitrates with 3,5,14,16-tetraazasubstituted dibenzo (d,j) (1,2,6,9,13,14) hexaazahexadeca-2,4,10,12-tetraene-7,8,15,16-tetraones. The authors carried out the investigations by means of conductimetry, UV luminescence, IR spectroscopy, and mass spectroscopy. Conductimetric titrations of the neodymium complexes were carried out on an OK-102/1 conductimeter. The luminescence spectra of the europium ion in the region of the /sup 5/D/sub 0/ ..-->.. /sup 7/F/sub 1/ and /sup 5/D/sub 0/ ..-->.. /sup 7/F/sub 2/ transitions (550-620 nm) were recorded on an ISP-51 spectrograph with an FEP-1 photoelectric attachment, using excitation by an SVD-120A mercury quartz lamp. The UV spectra of solutions of the compounds and the IR spectra of the solid substances in KBr disks were recorded on SpecordUViS and UR-20 spectrophotometers, respectively, and the mass spectra on a Varian Mat-112 spectrometer.

  12. Oxidative and nitrative stress in neurodegeneration.

    Science.gov (United States)

    Cobb, Catherine A; Cole, Marsha P

    2015-12-01

    Aerobes require oxygen for metabolism and normal free radical formation. As a result, maintaining the redox homeostasis is essential for brain cell survival due to their high metabolic energy requirement to sustain electrochemical gradients, neurotransmitter release, and membrane lipid stability. Further, brain antioxidant levels are limited compared to other organs and less able to compensate for reactive oxygen and nitrogen species (ROS/RNS) generation which contribute oxidative/nitrative stress (OS/NS). Antioxidant treatments such as vitamin E, minocycline, and resveratrol mediate neuroprotection by prolonging the incidence of or reversing OS and NS conditions. Redox imbalance occurs when the antioxidant capacity is overwhelmed, consequently leading to activation of alternate pathways that remain quiescent under normal conditions. If OS/NS fails to lead to adaptation, tissue damage and injury ensue, resulting in cell death and/or disease. The progression of OS/NS-mediated neurodegeneration along with contributions from microglial activation, dopamine metabolism, and diabetes comprise a detailed interconnected pathway. This review proposes a significant role for OS/NS and more specifically, lipid peroxidation (LPO) and other lipid modifications, by triggering microglial activation to elicit a neuroinflammatory state potentiated by diabetes or abnormal dopamine metabolism. Subsequently, sustained stress in the neuroinflammatory state overwhelms cellular defenses and prompts neurotoxicity resulting in the onset or amplification of brain damage. PMID:26024962

  13. Thorium Nitrate Stockpile Drum Characterization Report

    International Nuclear Information System (INIS)

    Thorium nitrate (ThN) has been stored at depots for several decades and the Defense National Stockpile Center (DNSC) has evaluated options for its disposition. In support of this project, Oak Ridge National Laboratory (ORNL) has directed a characterization campaign for the ThN. The analytical results lead to the following conclusions: the ThN could be classified as LSA-1; the ThN does not contain hazardous contaminants at concentrations that would cause it to be categorized as a mixed waste if were declared to be a waste; the ThN is not required to be classfied as a Division 5.1 oxidizer per the US Dept. of Transportation definition; and, the disposal of the ThN would not be regulated by the Resource Conservation and Recovery Act and thus it could be accepted for disposal at the Nevada Test Site. This report disucsses the regulatory requirements involved with the packaging, transportation, and disposal of the ThN stockpile at the NTS. It also provides background information about the ThN stockpile, the current packaging configurations, and the current storage arrangements. The reader is also provided a description of the ThN and headspace gas sampling activities that wer conducted in 2002 and 2003 respectively. The basis for using ISO containers to transport and dispose of the ThN is discussed

  14. Nitration of Polystyrene Part-I Effect of Molecular Weight of Polymer on Nitration

    Directory of Open Access Journals (Sweden)

    I. Bajaj

    1967-01-01

    Full Text Available Polystyrene in the molecular weight range, 3.67*10/Sup4 to 47.86*10/Sup10 has been nitrated in fuming nitric acid at 50 Degree C and degree of substitution of nitro group per monomeric unit in the polymer chains varying from 1.03 to 1.11 has been obtained. Molecular weight of the initial polymers have been found no appreciable effect on the degree of substitution. Degradation of the polymer chain is, however, found to be more pronounced in high molecular weight polymers.

  15. Evaluation of nitrate pollution of groundwater in Mnasra region

    International Nuclear Information System (INIS)

    Gharb area is one of the most important agricultural regions in Morocco, where the application of fertilizers is conducted in many cases without any respect of standards. This situation may generate negative environmental impact in vulnerable areas such as Mnasra groundwater. Our study tends to evaluate the level of contamination by nitrate of groundwater in a Mnasra area. The results show that 80% of the sampled wells are highly concentrated in nitrates in comparison with the standard of WHO. Intensification of agriculture in the area associated to excessive fertilizer application, repeated applications, irrigation and rainfall are reasons for an increasing nitrates pollution of water resources. Leaching of nitrate to the groundwater should receive more attention for its potential high mobile propriety which could cause serious damages for the environment and negative impact to the health of population.

  16. Evaluation of nitrate dynamics in riparian zones using environmental isotopes

    International Nuclear Information System (INIS)

    Nitrate contamination, often associated with agricultural activities, is a major problem in some shallow aquifers in Canada and is an increasing threat to groundwater supplies and surface water quality. The studies to be presented at this conference are part of a major project aiming to examine the function of riparian zones in watersheds dominated by agricultural areas. Specifically, this project focuses on the role of vegetation strips and wetlands as buffer zones to attenuate groundwater nitrate generated by agricultural activities, that ultimately impact surface water. Our research approach involves combining the hydrology, geochemistry, ecology and stratigraphic analyses of the riparian zone in a multi-disciplinary way. 15N and 18O in nitrate are being used to provide information on the sources and to allow us to separate denitrification from nitrate attenuation by dilution

  17. Heterogeneous Interaction of Peroxyacetyl Nitrate on Liquid Sulfuric Acid

    Science.gov (United States)

    Zhang, Renyi; Leu, Ming-Taun

    1996-01-01

    The uptake of peroxyacetyl nitrate (PAN) on liquid sulfuric acid surfaces has been investigated using a fast-flow reactor coupled to a chemical ionization mass spectrometer. PAN was observed to be reversibly adsorbed on sulfuric acid.

  18. Deprotection of oximes using urea nitrate under microwave irradiation

    Indian Academy of Sciences (India)

    P T Perumal; M Anniyappan; D Muralidharan

    2004-08-01

    A new mild and efficient method for the cleavage of oximes to carbonyl compounds using readily available urea nitrate in acetonitrile-water (95 : 5), under microwave irradiation within 2 min, in good yields is reported.

  19. Nitrates in the human diet - good or bad?

    OpenAIRE

    Benjamin, Nigel

    2000-01-01

    Les nitrates dans l'alimentation humaine : une bonne ou une mauvaise chose ? Bien que les nitrates soient connus depuis des siècles, c'est seulement depuis peu qu'il a été découvert que les nitrates sont synthétisés chez les mammifères à partir du monoxyde d'azote, et que les nitrates formés ont la capacité de tuer les bactéries présentes dans les aliments consommés. Les mécanismes par lesquels le monoxyde d'azote et d'autres oxydes d'azote manifestent une toxicité sélective vis-à-vis de bact...

  20. Nitrate leaching from short-hydroperiod floodplain soils

    Directory of Open Access Journals (Sweden)

    B. Huber

    2012-11-01

    Full Text Available Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3 contamination coming from adjacent agricultural land. Much less is known about nitrogen (N transformations and nitrate fluxes in riparian soils with short hydroperiods (1–3 days of inundation and there is no study that could show whether these soils are a N sink or source. Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation and N output (leaching to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater. Overall, the main factor explaining the differences in nitrate concentrations was the field capacity (FC. In subsoils with high FCs and VWC near FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol L−1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha−1 yr−1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3 ha−1 yr−1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11% to the total nitrate load in groundwater.

  1. Nitrate leaching from short-hydroperiod floodplain soils

    Directory of Open Access Journals (Sweden)

    B. Huber

    2012-05-01

    Full Text Available Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3 contamination coming from adjacent agricultural land. Much less is known about nitrogen (N transformations and nitrate fluxes in riparian soils with short hydroperiods (1–3 days of inundation and there is no study that could show whether these soils are a N sink or source.

    Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation and N output (leaching to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater.

    Overall, the main factor explaining the differences in nitrate concentrations was the variability in soil texture and volumetric water content (VWC at field capacity (FC. In subsoils with high VWC at FC and VWC near 100 % FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol l−1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha−1 yr−1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3 ha−1 yr−1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11 % to the total nitrate load in groundwater.

  2. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER

    International Nuclear Information System (INIS)

    A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), and extremely inexpensive and easy to emplace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels has been discharged from this plant for many years, until recently when the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated this past year to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier. will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mhl nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 microM perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system

  3. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER

    Energy Technology Data Exchange (ETDEWEB)

    B. STRIETELMEIER; M. ESPINOSA

    2001-01-01

    A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), extremely inexpensive, and easy to replace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels was discharged from this plant for many years. Recently, the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated in 1999 to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mM nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.

  4. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER

    Energy Technology Data Exchange (ETDEWEB)

    B. STRIETELMEIR; ET AL

    2000-12-01

    A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), and extremely inexpensive and easy to emplace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels has been discharged from this plant for many years, until recently when the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated this past year to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier. will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mhl nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.

  5. Low serum total nitrite and nitrate levels in severe leptospirosis

    OpenAIRE

    Kalugalage, Thilini; Rodrigo, Chaturaka; Vithanage, Thamal; Somaratne, Pranitha; de Silva, H. Janaka; Handunnetti, Shiroma; Rajapakse, Senaka

    2013-01-01

    Background The relationship between inducible nitric oxide synthatase activity and disease severity in leptospirosis is unclear. Nitric oxide is converted to nitrites and nitrates, thus nitrite and nitrate levels (NOx) in serum are considered surrogate markers for nitric oxide. NOx are excreted through the kidneys, and elimination is diminished in renal impairment. We assessed the correlation of NOx with disease severity in patients with leptospirosis, compared with healthy controls and non-l...

  6. Radiolysis studies of uranyl nitrate solution in nitric acid medium

    International Nuclear Information System (INIS)

    The radiolysis of acidic uranyl nitrate solutions was investigated using Co-60 gamma radiation. Hydrogen peroxide was determined as a function of increasing dose. The UV-vis absorption spectra of the irradiated solutions were measured and the spectral changes were analyzed. The increasing dose increases the absorbance intensities, possibly by an increment in nitrate concentration produced by radiolysis, which can originate the formation of different uranyl complexes in solution. (author)

  7. Nitrate assimilation in plant shoots depends on photorespiration

    OpenAIRE

    Rachmilevitch, Shimon; Cousins, Asaph B.; Bloom, Arnold J.

    2004-01-01

    Photorespiration, a process that diminishes net photosynthesis by ≈25% in most plants, has been viewed as the unfavorable consequence of plants having evolved when the atmosphere contained much higher levels of carbon dioxide than it does today. Here we used two independent methods to show that exposure of Arabidopsis and wheat shoots to conditions that inhibited photorespiration also strongly inhibited nitrate assimilation. Thus, nitrate assimilation in both dicotyledonous and monocotyledono...

  8. Multiparameter emergency-situation evaluation system for nitration processes

    Energy Technology Data Exchange (ETDEWEB)

    Sakhnenko, V.I.; Serov, Y.V.; Ulanov, V.N. [Technological Inst., St. Petersburg (Russian Federation)] [and others

    1992-08-10

    Nitration is widely used in making drugs, vitamins, dyes, perfumery components, corrosion inhibitors to be added to engine fuels, and additives for fuels to raise the cetane numbers. In nitration systems, emergency control measures may be based on majority-logic processing (two out of three), which improves the probability of fault-free operation in the protection system. The theoretical concepts are supported by experiments and calculations. 18 refs., 5 figs., 1 tab.

  9. Nitrates and Nitrites in the Treatment of Ischemic Cardiac Disease

    OpenAIRE

    Nossaman, Vaughn E.; Nossaman, Bobby D.; Kadowitz, Philip J.

    2010-01-01

    The organic nitrite, amyl of nitrite, was initially used as a therapeutic agent in the treatment of angina pectoris in 1867, but was replaced over a decade later by the organic nitrate, nitroglycerin (NTG), due to the ease of administration and longer duration of action. The administration of organic nitrate esters, such as NTG, continues to be used in the treatment of angina pectoris and heart failure during the birth of modern pharmacology. The clinical effectiveness is due to vasodilator a...

  10. Sucrose mimics the light induction of Arabidopsis nitrate reductase gene transcription

    DEFF Research Database (Denmark)

    Cheng, Chi-Lien; Acedo, Gregoria N; Kristensen, Michael;

    1992-01-01

    Nitrate reductase, the first enzyme in nitrate assimilation, is located at the crossroad of two energy-consuming pathways: nitrate assimilation and carbon fixation. Light, which regulates the expression of many higher-plant carbon fixation genes, also regulates nitrate reductase gene expression. ...

  11. Nitrate from agriculture: moving from uncertain data to operational responses

    Science.gov (United States)

    Hart, Alwyn; Bieroza, Magdalena

    2015-04-01

    The Nitrates Directive (91/676/EEC) is designed to protect waters against nitrate pollution from agricultural sources. It requires Member States to identify waters which are, or could become, polluted by nitrates and to designate as Nitrate Vulnerable Zones (NVZs) all land draining to those waters and contributing to the pollution. To meet these requirements, Department for Environment Food & Rural Affairs (Defra) have commissioned reviews that designated NVZs in 1993, 1998, 2002, 2008 and 2013. The designation methods used have evolved over this time and have been developed with the close involvement of farming and water company representatives and with advice and guidance from a number of independent external technical experts. The monitoring network and methods change frequently and methods need to be developed which are robust enough to cope with gaps in data, both geographical and temporal. This project is aimed at investigating new approaches for identifying waters that are at risk of nitrate pollution and the land that drains to these and builds on a large body of evidence supporting understanding of nitrate in the environment. The work will demonstrate to Defra and to the wider community that the most cost efficient and appropriate methods to designate NVZ areas for groundwater and surface water are used.

  12. Photochemistry of adsorbed nitrate on aluminum oxide particle surfaces.

    Science.gov (United States)

    Rubasinghege, Gayan; Grassian, Vicki H

    2009-07-01

    Nitrogen oxides, including nitrogen dioxide and nitric acid, react with mineral dust particles in the atmosphere to yield adsorbed nitrate. Although nitrate ion is a well-known chromophore in natural waters, little is known about the surface photochemistry of nitrate adsorbed on mineral particles. In this study, nitrate adsorbed on aluminum oxide, a model system for mineral dust aerosol, is irradiated with broadband light (lambda > 300 nm) as a function of relative humidity (RH) in the presence of molecular oxygen. Upon irradiation, the nitrate ion readily undergoes photolysis to yield nitrogen-containing gas-phase products including NO(2), NO, and N(2)O, with NO being the major product. The relative ratio and product yields of these gas-phase products change with RH, with N(2)O production being highest at the higher relative humidities. Furthermore, an efficient dark reaction readily converts the major NO product into NO(2) during post-irradiation. Photochemical processes on mineral dust aerosol surfaces have the potential to impact the chemical balance of the atmosphere, yet little is known about these processes. In this study, the impact that adsorbed nitrate photochemistry may have on the renoxification of the atmosphere is discussed. PMID:19534452

  13. Immobilization of sodium nitrate waste with polymers: Topical report

    International Nuclear Information System (INIS)

    This report describes the development of solidification systems for sodium nitrate waste. Sodium nitrate waste was solidified in the polymers polyethylene, polyester-styrene (PES), and water-extendible polyester-styrene (WEP). Evaluations were made of the properties of waste forms containing various amounts of sodium nitrate by leaching immersion in water, measuring compressive strengths and by the EPA Extraction Procedure. Results of the leaching test are presented as cumulative fraction leached (CFL), incremental leaching rate, and average leaching indices (LI). For waste forms containing 30 to 70 wt% sodium nitrate, the CFL ranged from 9.0 x 10-3 to 7.3 x 10-1 and the LI from 11 to 7.8. After ninety days immersion in water, the compressive strengths ranged from 720 psi to 2550 psi. The nitrate releases from these samples using the EPA Extraction Procedure were below 500 ppM. The nitrate releases from PES waste forms were similar to those from polyethylene waste forms at the same waste loadings. The compressive yield strengths, measured after ninety-day immersion in water, ranged between 2070 and 7710 psi. In the case of WEP waste forms, only 30 wt% loaded samples passed the immersion test. 23 refs., 24 figs., 12 tabs

  14. Denitrifying Bioreactors for Nitrate Removal: A Meta-Analysis.

    Science.gov (United States)

    Addy, Kelly; Gold, Arthur J; Christianson, Laura E; David, Mark B; Schipper, Louis A; Ratigan, Nicole A

    2016-05-01

    Meta-analysis approaches were used in this first quantitative synthesis of denitrifying woodchip bioreactors. Nitrate removal across environmental and design conditions was assessed from 26 published studies, representing 57 separate bioreactor units (i.e., walls, beds, and laboratory columns). Effect size calculations weighted the data based on variance and number of measurements for each bioreactor unit. Nitrate removal rates in bed and column studies were not significantly different, but both were significantly higher than wall studies. In denitrifying beds, wood source did not significantly affect nitrate removal rates. Nitrate removal (mass per volume) was significantly lower in beds with effects with bed temperature; a of 2.15 was quite similar to other studies. Lessons from this meta-analysis can be incorporated into bed designs, especially extending hydraulic retention times to increase nitrate removal under low temperature and high flow conditions. Additional column studies are warranted for comparative assessments, as are field-based studies for assessing in situ conditions, especially in aging beds, with careful collection and reporting of design and environmental data. Future assessment of these systems might take a holistic view, reviewing nitrate removal in conjunction with other processes, including greenhouse gas and other unfavorable by-product production. PMID:27136153

  15. Nitrate-transformations during simulated drought on a restored floodplain

    Science.gov (United States)

    Hoagland, B.; Russo, T. A.; Schmidt, C. M.; Tran, D.

    2015-12-01

    Water resources in the California Central Valley face challenges due to recurring drought, aging levee systems, and nitrate contamination. As decisions are made to restore floodplain connectivity, soil microbial metabolic pathways such as denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) transform nitrate under saturated soil conditions and may each affect downstream water quality. However, few studies have quantified the contribution of all three pathways to nitrate retention in freshwater systems, and specifically in restored floodplains. Additionally, no former studies quantify the rates of these microbial nitrate transformations during floods after prolonged periods of drought. To test how flood duration impacts nitrogen cycling we added 15N-enriched tracer to soil mesocosms to measure denitrification, anammox, and DNRA transformation rates. In July 2015, we extracted seven soil mesocosms from the floodplain and riverbed of the Lower Cosumnes River in the San Joaquin Basin of California. Cosumnes River water enriched with 15N-NO3- tracer was pumped into each mesocosm at a constant rate simulating flood durations of 20 h, 30 h, and 96 h. Samples were collected from the surface water, soil pore water, drain water, and sediment for measurements of NO3-, NO2-, NH4+, gas isotopes, and DNA extraction. This study aims to demonstrate the relevance of anammox and DNRA to total nitrate retention and characterize the hydrologic conditions most favorable to each pathway.

  16. Effect of nitrate poisoning on some biochemical parameters in rats

    Directory of Open Access Journals (Sweden)

    M. B. Mahmood

    2011-01-01

    Full Text Available The present study was conducted to investigate the toxicity of potassium nitrate on glucose, cholesterol, alanine aminotransferase (ALT, aspartate aminotransferase (AST, and the possible ameliorative effect of ascorbic acid (Vitamin C. Male Wister rats are used as experimental model divided into three groups (each of 6-8 rats and treated for six weeks as follows: Group 1: served as control; Group 2: received 2 % potassium nitrate added to the forage and Group 3: received 2 % potassium nitrate together with 1 % ascorbic acid added to rat's forage. Nitrate treatment in group 2 leads to high significant increase levels of glucose in 3rd, 4th, and 5th weeks, cholesterol level increased significantly in both 4th and 5th weeks, while ALT levels increased in the 4th, 5th and 6th weeks, and AST increased significantly in the 5th and 6th weeks. Addition of ascorbic acid with potassium nitrate, lead to reverse all the parameters nearly to normal. It was concluded that potassium nitrate causes significant toxic effect on some biochemical parameters which was ameliorated by ascorbic acid.

  17. Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

    2016-02-01

    Intertidal marshes are alternately exposed and submerged due to periodic ebb and flood tides. The tidal cycle is important in controlling the biogeochemical processes of these ecosystems. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium, remains unexplored in these habitats. Here, we use isotope-tracing and molecular approaches simultaneously to show that both nitrate-reduction activities and associated functional bacterial abundances are enhanced at the sediment-tidal water interface and at the tide-induced groundwater fluctuating layer. This pattern suggests that tidal pumping may sustain dissimilatory nitrate reduction in intertidal zones. The tidal effect is supported further by nutrient profiles, fluctuations in nitrogen components over flood-ebb tidal cycles, and tidal simulation experiments. This study demonstrates the importance of tides in regulating the dynamics of dissimilatory nitrate-reducing pathways and thus provides new insights into the biogeochemical cycles of nitrogen and other elements in intertidal marshes.

  18. Use of the δ18O and δ15N of nitrate to determine sources of nitrate in early spring runoff in forested catchments

    International Nuclear Information System (INIS)

    Many upland catchments have increased nitrate and hydrogen ion concentrations in stream water during the early snowmelt period. The dominant source of this nitrate is not well known, but likely contributors include atmospheric deposition of nitrate and ammonium in the snowpack, and soil derived nitrate. Pilot studies initiated in three catchments during the 1994 snowmelt season show that analysis of both the δ18O and δ15N of nitrate provides excellent separation of nitrate sources. Almost all the stream samples have nitrate δ18O and δ15N values within the range of the pre-melt soil and stream waters, suggesting that atmospheric nitrate eluted from the 1994 snowpack is a minor source of nitrate in early streamflow. Therefore, the nitrate eluted from the 1994 snowpack appears to go into storage, and most of the nitrate in streamflow during the period of potential acidification was derived from pre-melt sources. The δ18O of pre-melt nitrate in soil and stream waters is intermediate between the compositions of atmospheric and solid derived nitrate, indicating a mixture of sources. The enriched composition of the pre-melt nitrate suggests that either atmospheric nitrate is actually a dominant source of nitrate to the catchment on a yearly basis, or that there is recharge of shallow storage by percolating snowmelt during midwinter thaws. In either case, the nitrate pulse in stream water during early melt appears to be largely derived from precipitation from previous months or years that is flushed from storage. (author). 12 refs, 2 figs

  19. Monitoring of nitrate content of vegetable crops in Uzhgorod district

    Directory of Open Access Journals (Sweden)

    I.I. Mykaylo

    2013-09-01

    Full Text Available The aim of our research was to conduct a monitoring study of nitrate content in plant products of Uzhgorod district and to accomplish comparative analysis of the survey results in different periods of crop ripening. Selection of vegetable samples was carried out in Uzhgorod district in the early spring and summer periods. Determination of the nitrate content was performed using an ion-selective method at the Chemical and Toxicological Department of the Regional State Veterinary Medicine Laboratory in the Transcarpathian region of Ukraine. Vegetables were tested for nitrate content using the ion-selective method with the laboratory ion meter AI-123. Core investigation samples were crushed and homogenized. A 10.0 g weight of the investigated product, which was prepared according to MIR № 5048-89, was placed in a flat-bottomed or a conical flask, which was then filled with 50 cm3 potassium alumens solution and shaken in a shaking-machine for 5 minutes and then transferred into a measuring glass. The nitrate weight fraction in milligrams per kilogram was obtained together with the weight concentration value of nitrate ions in solution. For our study we selected vegetables grown in both public and private gardens of Uzhgorod district, namely: common onions, radishes, garden parsley, cucumbers, tomatoes, bell peppers, white cabbages, carrots and table beets. 25 samples were selected for each type of vegetable. Nitrate content was determined in the early spring growing period (from February 9 to May 27, 2011 and in the summer growing period (from June 3 to September 28, 2011, because in these particular periods we recorded the most frequent cases of food poisoning from nitrates among the population of the region. A clear trend has been traced towards increasing the nitrate content in food plant production, at levels which exceed the maximum permissible concentration (MPC. The results of our research demonstrate that the nitrate content exceeded the

  20. Nitrate reductase regulation in tomato roots by exogenous nitrate: a possible role in tolerance to long-term root anoxia

    OpenAIRE

    Allègre, Adeline; Silvestre, Jérôme; Morard, Philippe; Kallerhoff, Jean; Pinelli, Eric

    2004-01-01

    The mechanism of nitrate reductase (NR) regulation under long-term anoxia in roots of whole plants and the putative role of nitrate in anoxia tolerance have been addressed. NR activity in tomato roots increased significantly after 24 h of anaerobiosis and increased further by 48 h, with a concomitant release of nitrite into the culture medium. Anoxia promoted NR activation through dissociation of the 14-3-3 protein inhibitor and NR dephosphorylation. After 24 h of anoxia, the total amount of ...

  1. Solvent extraction of nitrates of the lanthanides (3) and yttrium (3) by trialkylmethylammonium nitrate from multi-component solutions

    International Nuclear Information System (INIS)

    Extraction of lanthanides (3) and yttrium (3) nitrates from multicomponent solutions by tralkylmethylammonium nitrate at 298.15 K and pH 2 has been considered. Physicochemical and mathematical models describing lanthanide (3) (praseodymium-lutetium) and yttrium (3) distribution in multicomponent solutions, depending on total concentration of rare earth metals ion concentration in aqueous solution and composition of concentrate, are presented. 7 refs., 5 figs., 1 tab

  2. Extraction of rare earth(III) nitrates by composite materials on the basis of polymer carrier, trialkylmethylammonium nitrate and TBP

    International Nuclear Information System (INIS)

    Extraction of Eu-Lu(III) and Y(III) nitrates by composite materials on the basis of polymer carrier, trialkylmethylammonium nitrate and TBP is studied in the presence of 1-5 mol/dm3 NaNO3 in aqueous phase. Extraction isotherms are described taking into account the formation of compounds (R4N)[Ln(NO3)5 and [Ln(NO3)3(TBP)3] in the phase of composite material; extraction constants are determined

  3. Functional complementation of a nitrate reductase defective mutant of a green alga Dunaliella viridis by introducing the nitrate reductase gene.

    Science.gov (United States)

    Sun, Yu; Gao, Xiaoshu; Li, Qiyun; Zhang, Qingqi; Xu, Zhengkai

    2006-08-01

    Nitrate reductase (NR) catalyzes NAD (P) H dependent reduction of nitrate to nitrite. Transformation systems have been established in several species of green algae by nitrate reductase gene functional complementation. In this report, an endogenous NR cDNA (3.4 kb) and a genomic fragment (14.6 kb) containing the NR gene (DvNIA1) were isolated from the D. viridis cDNA and genomic libraries respectively. Southern blot and Northern blot analyses showed that this gene exists as a single copy in D. viridis and is induced by nitrate. To obtain a NR defective mutant as a recipient strain, D. viridis cells were treated with a chemical mutagen and then cultured on a chlorate-containing plate to enrich chlorate tolerant mutants. Southern analysis showed that one isolate, B14, had a deletion in the DvNIA1 gene region. Using electroporation conditions determined in this laboratory, plasmid pDVNR containing the intact DvNIA1 gene has been electroporated into the defective mutant B14. Strains retaining a nitrate assimilation phenotype were obtained from nitrate plates after spreading the electroporated cells. In some individual strains, transcription of the introduced gene was detected. NR activity in these strains was slightly higher than that in the defective B14 cell, but excretion of nitrite into culture media was almost as high as that of the wild-type cell. Possible episomal presence of the introduced DNA in D. viridis is discussed. PMID:16797881

  4. Influence of organic carbon sources and isotope exchange processes between water and nitrate on the fractionation of the stable isotopes 15N/14N and 18O/16O in dissolved nitrate during microbial dentrification in groundwater

    International Nuclear Information System (INIS)

    Stable isotopes of nitrate are commonly used to determine sources and degradation of nitrate. In this study, nitrite oxidizing bacteria were found to promote an oxygen isotope exchange between water and nitrate under anoxic conditions. Also, different carbon sources were found to influence the enrichment of stable isotopes in nitrate during microbial denitrification. Both results refine the stable isotope model of nitrate in respect to nitrate source determination and microbial nitrate reduction.

  5. Aerosol nitrate from lightning - from sources to impacts

    Science.gov (United States)

    Tost, Holger

    2016-04-01

    Particulate nitrate is a key component on the inorganic atmospheric aerosol composition. Due to its semi-volatility, an accurate description of the budget and the impacts of nitrate aerosol are still somewhat uncertain. To address some of the impacts of nitrate, in this study we explicitly analyse the impact of aerosol nitrate from a natural source, namely lightning. As the lightning NOx emissions are only a contribution to the total NOx emissions, this example does not resemble a typical annihilation scenario, which might substantially misjudge the effect of aerosol nitrate due to the high non-linearity in the nitrate budget, but also other directly connected compounds, but tries to shed light onto the sensitivity of aerosol nitrate and its effects. On the other hand, lightning represents an emission source of NOx, which is partly injected directly in the upper troposphere, where due to its longer lifetime and the temperature dependent stability of NH4NO3 aerosol nitrate can form much easier and has a longer lifetime against decomposition. This study uses a comprehensive chemistry climate model to track the evolution of aerosol nitrate from the lightning NOx emission, via chemical processing and gas-aerosol partitioning, aerosol microphyiscal processes down to the climatic impacts of the nitrate aerosol particles via direct aerosol-radiation and aerosol-cloud interactions. All of these processes are explicitly considered with the help of state-of-the-art (parameterisation) schemes, including a comprehensive multi-phase chemistry configuration, a microphysical and chemical composition aerosol model, aerosol optical properties and a two-moment cloud microphysical scheme with explicit activation of aerosol particles into cloud droplets and the consideration of aerosol particles in ice formation processes. Furthermore, some uncertainty with respect to cloud droplet formation has been considered by using two different aerosol activation schemes. To estimate the

  6. On the origin of the occasional spring nitrate peak in Greenland snow

    OpenAIRE

    Geng, L.; J. Cole-Dai; Alexander, B; Erbland, J.; J. Savarino; A. J. Schauer; E. J. Steig; Lin, P.; Fu, Q; Zatko, M. C.

    2014-01-01

    Ice core nitrate concentrations peak in the summer in both Greenland and Antarctica. Two nitrate concentration peaks in one annual layer have been observed some years in ice cores in Greenland from samples dating post-1900, with the additional nitrate peak occurring in the spring. The origin of the spring nitrate peak was hypothesized to be pollution transport from the mid-latitudes in the industrial era. We performed a case study on the origin of a spring nitrate peak in 20...

  7. Physiology and interaction of nitrate and nitrite reduction in Staphylococcus carnosus.

    OpenAIRE

    Neubauer, H.; Götz, F

    1996-01-01

    Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characterized. Nitrate reductase seems to be a membrane-bound enzyme involved in respiratory energy conserva...

  8. Problems Caused by Microbes and Treatment Strategies The Effect of Nitrate Injection in Oil Reservoirs - Experience with Nitrate Injection in the Halfdan Oilfield

    Science.gov (United States)

    Larsen, Jan; Skovhus, Torben Lund

    This chapter deals with the use of nitrate injection for reservoir souring mitigation in an oilfield with seawater injection in the Danish sector of the North Sea. Nitrate impacts on the activity of sulphate-reducing bacteria (SRB) and biofilm redox potential (Larsen et al., 2007), as a result of which corrosion due to SRB activity will be reduced, souring inhibited and previously formed sulphide removed (Larsen, 2002). One important aspect is that the microbiological reduction of nitrate provides approximately three times more energy to SRB than the reduction of sulphate. Therefore, when both nitrate and sulphate are present, nitrate becomes the preferred electron acceptor and SRB capable of growing on nitrate will dominate. Nitrate provides a competitive advantage to nitrate-utilising bacteria (indicated by the general acronym NUB) during competition for available carbon sources as the NUB are capable of much faster growth than SRB.

  9. Microbial response to nitrate treatment in offshore oil fields

    Energy Technology Data Exchange (ETDEWEB)

    Boedtker, Gunhild

    2009-07-01

    North Sea oil reservoirs are often injected with deaerated sea water in order to enhance oil recovery. The high sulphate content of sea water combined with the anoxic conditions stimulates growth of sulphate-reducing bacteria (SRB) in the water injection system and the reservoir. SRB produce the highly toxic and corrosive gas hydrogen sulphide (HZS) during anaerobic respiration with sulphate. Accumulation of HZS leads to corrosion and reservoir souring, which may result in reduced gas quality, separation problems and increased maintenance costs. Biocides have traditionally been used to prevent SRB activity in North Sea oil fields. During the last decade, however, the environmentally sound method of nitrate treatment has replaced biocides on several fields. The method is based on shifting the microbial activity from sulphate reduction to nitrate reduction by introducing nitrate as an alternative electron acceptor for anaerobic respiration. Results presented in the current thesis show that nitrate treatment has resulted in long-term inhibition of SRB activity and a reduction in corrosion of up to 40% in sea water injection systems at the Veslefrikk and Gullfaks oil fields. Molecular analysis (PCR-DGGE) of pipeline biofilm from Veslefrikk showed that sulphide-oxidizing nitrate-reducing bacteria (NR-SOB) constituted the major metabolic group during nitrate treatment, and that the bacterial community composition remained stable during years. Reduction in sulphide produced from the Gullfaks field showed that nitrate treatment was effective also at reservoir level. Analysis of back flowed injection water from a nitrate-treated Statfjord reservoir showed that heterotrophic nitrate-reducing bacteria (hNRB) constituted the major metabolic group, and that the in situ HZS level was 10 fold lower than experienced during biocides treatment and 100 fold lower than experienced during produced water reinjection (PWRI). At the Norne oil field oxic sea water is injected along with

  10. The changing trend in nitrate concentrations in major aquifers due to historical nitrate loading from agricultural land across England and Wales from 1925 to 2150.

    Science.gov (United States)

    Wang, L; Stuart, M E; Lewis, M A; Ward, R S; Skirvin, D; Naden, P S; Collins, A L; Ascott, M J

    2016-01-15

    Nitrate is necessary for agricultural productivity, but can cause considerable problems if released into aquatic systems. Agricultural land is the major source of nitrates in UK groundwater. Due to the long time-lag in the groundwater system, it could take decades for leached nitrate from the soil to discharge into freshwaters. However, this nitrate time-lag has rarely been considered in environmental water management. Against this background, this paper presents an approach to modelling groundwater nitrate at the national scale, to simulate the impacts of historical nitrate loading from agricultural land on the evolution of groundwater nitrate concentrations. An additional process-based component was constructed for the saturated zone of significant aquifers in England and Wales. This uses a simple flow model which requires modelled recharge values, together with published aquifer properties and thickness data. A spatially distributed and temporally variable nitrate input function was also introduced. The sensitivity of parameters was analysed using Monte Carlo simulations. The model was calibrated using national nitrate monitoring data. Time series of annual average nitrate concentrations along with annual spatially distributed nitrate concentration maps from 1925 to 2150 were generated for 28 selected aquifer zones. The results show that 16 aquifer zones have an increasing trend in nitrate concentration, while average nitrate concentrations in the remaining 12 are declining. The results are also indicative of the trend in the flux of groundwater nitrate entering rivers through baseflow. The model thus enables the magnitude and timescale of groundwater nitrate response to be factored into source apportionment tools and to be taken into account alongside current planning of land-management options for reducing nitrate losses. PMID:26546765

  11. Difficulties in the Nitrates Directive Implementation in Romania

    Directory of Open Access Journals (Sweden)

    MIHĂIESCU Tania

    2010-12-01

    Full Text Available The EU Nitrates Directive (Council Directive 91/676/EEC forms an integrate part of the Water FrameworkDirective and is one of the key instruments in the protection of waters against agricultural pressures [6]. The NitratesDirective aims to protect water quality across Europe by reducing water pollution caused or induced by nitrates fromagricultural sources and by promoting the use of good agricultural practices. Implementation of this directive hasproved to be a major challenge for Member States, demanding vast technical resources for the characterization and riskassessments and for developing and operating the associated monitoring programmes, in order to quantify the efficiencyof the implemented measures. The 2010 EC's report on the implementation of the Nitrates Directive shows that thepressure from agriculture with respect to surface and groundwater nitrate pollution has decreased in many MemberStates, although still, agriculture contributes largely to nitrogen loads to surface and ground waters [7]. However,despite these encouraging trends, the report reveals a number of regions where nitrate levels, according to monitoringdata, are worrying; one among them is also the southern part of Romania. Although major pollutant sources such aslarge intensive rearing of poultry and pig farms ceased or conformed to the IPPC directive, achievement of the Nitratesdirective goals is still far away from realization due to livestock husbandry farms bad waste management and due to thelack of waste water treatment stations in rural settlements. Accomplishment of the nitrates directive demands has to berealized, in the case of Romania, by a concertated array of measures aimed at reducing pollution both at major and lessimportant sources [9], [10].

  12. Analytical Characterization of the Thorium Nitrate Stockpile

    Energy Technology Data Exchange (ETDEWEB)

    Mattus, CH

    2003-12-30

    For several years, Oak Ridge National Laboratory (ORNL) has been supporting the Defense Logistics Agency-Defense National Stockpile Center with stewardship of a thorium nitrate (ThN) stockpile. The effort for fiscal year 2002 was to prepare a sampling and analysis plan and to use the activities developed in the plan to characterize the ThN stockpile. The sampling was performed in June and July 2002 by RWE NUKEM with oversight by ORNL personnel. The analysis was performed by Southwest Research Institute of San Antonio, Texas, and data validation was performed by NFT, Inc., of Oak Ridge, Tennessee. Of the {approx} 21,000 drums in the stockpile, 99 were sampled and 53 were analyzed for total metals composition, radiological constituents (using alpha and gamma spectrometry), and oxidizing characteristics. Each lot at the Curtis Bay Depot was sampled. Several of the samples were also analyzed for density. The average density of the domestic ThN was found to be 1.89 {+-} 0.08 g/cm{sup 3}. The oxidizer test was performed following procedures issued by the United Nations in 1999. Test results indicated that none of the samples tested was a Division 5.1 oxidizer per Department of Transportation definition. The samples were analyzed for total metals following the U.S. Environmental Protection Agency methods SW-846-6010B and 6020 (EPA 2003) using a combination of inductively coupled plasma--atomic emission spectroscopy and inductively coupled plasma--mass spectroscopy techniques. The results were used to compare the composition of the eight Resource Conservation and Recovery Act metals present in the sample (arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver) to regulatory limits. None of the samples was found to be hazardous for toxicity characteristics. The radiological analyses confirmed, when possible, the results obtained by the inductively coupled plasma analyses. These results--combined with the historical process knowledge acquired on the material

  13. Nitrate production and availability in residential soils.

    Science.gov (United States)

    Raciti, Steve M; Groffman, Peter M; Jenkins, Jennifer C; Pouyat, Richard V; Fahey, Timothy J; Pickett, Steward T A; Cadenasso, Mary L

    2011-10-01

    The rapid increase in residential land area in the United States has raised concern about water pollution associated with nitrogen fertilizers. Nitrate (NO3-) is the form of reactive N that is most susceptible to leaching and runoff; thus, a more thorough understanding of nitrification and NO3(-) availability is needed if we are to accurately predict the consequences of residential expansion for water quality. In particular, there have been few assessments of how the land use history, housing density, and age of residential soils influence NO3(-) pools and fluxes, especially at depth. In this study, we used 1 m deep soil cores to evaluate potential net nitrification and mineralization, microbial respiration and biomass, and soil NO3(-) and NH4+ pools in 32 residential home lawns that differed by previous land use and age, but had similar soil types. These were compared to eight forested reference sites with similar soils. Our results suggest that a change to residential land use has increased pools and production of reactive N, which has clear implications for water quality in the region. However, the results contradict the common assumption that NO3(-) production and availability is dramatically higher in residential soils than in forests in general. While net nitrification (128.6 +/- 15.5 mg m(-2) d(-1) vs. 4.7 +/- 2.3 mg m(-2) d(-1); mean +/- SE) and exchangeable NO3(-) (3.8 +/- 0.5 g/m2 vs. 0.7 +/- 0.3 g/m2) were significantly higher in residential soils than in forest soils in this study, these measures of NO3(-) production and availability were still notably low, comparable to deciduous forest stands in other studies. A second unexpected result was that current homeowner management practices were not predictive of NO3(-) availability or production. This may reflect the transient availability of inorganic N after fertilizer application. Higher housing density and a history of agricultural land use were predictors of greater NO3(-) availability in residential

  14. Investigating the Effect of Three Nitrate Fertilizers on Nitrate Leaching under the Root Zone in Clay Loam Soil

    Directory of Open Access Journals (Sweden)

    Thamer A. Mohammed

    2009-01-01

    Full Text Available Problem statement: Nitrogen fertilizer is recognized as an important factor in crop’s yield level, however more application of N fertilizers in the soil have some adverse effects on environment and especially on ground water contamination. Perception and recognition the factors influencing nitrate transport through soil profile is helpful for fertilizer management to minimize adverse impacts on environment and nitrate leaching below the root zone. Approach: In this study, 9 large cylindrical lysimeters with 1 m height and 0.5 m diameter were filled with clay loam soil and planted with maize to investigate nitrate leaching under different types of N-fertilizer, chemical fertilizer, activated sludge and organic manure. Nitrate concentration in the soil and drainage water samples were analyzed by spectrophotometer method and the mass of nitrate was calculated in soil and drainage water. Crop productions for different treatments were compared too. Results: Results showed that cumulative mass of nitrate leaching from organic fertilizer was greater than the other treatments (229 kg ha-1. Organic manure had the greatest nitrate accumulation in soil (15.17 mg kg-1, which was significantly greater than chemical fertilizer. Conclusions/Recommendations: experimental results showed that manure application could result in NO3--N accumulation increase in the deeper soil profiles compared with activated sludge. Results showed that maize production was significantly higher under activated sludge fertilizer. Observations made in the current study suggested activated sludge fertilizer due to a higher crop production with same level of ground water contamination, especially in clay loam soils.

  15. Influence of carbon source on nitrate removal by nitrate-tolerant Klebsiella oxytoca CECT 4460 in batch and chemostat cultures

    Energy Technology Data Exchange (ETDEWEB)

    Pinar, G.; Ramos, J.L. [Consejo Superior de Investigaciones Cientificas, Granada (Spain); Kovarova, K.; Egli, T. [Swiss Federal Inst. for Environmental Science and Technology, Duebendorf (Switzerland). Dept. of Microbiology

    1998-08-01

    The nitrate-tolerant organism Klebsiella oxytoca CECT-4460 tolerates nitrate at concentrations up to 1 M and is used to treat wastewater with high nitrate loads in industrial wastewater treatment plants. The authors studied the influence of the C source (glycerol or sucrose or both) on the growth rate and the efficiency of nitrate removal under laboratory conditions. With sucrose as the sole C source the maximum specific growth rate was 0.3 h{sup {minus}1}, whereas with glycerol it was 0.45 h{sup {minus}1}. In batch cultures K. oxytoca cells grown on sucrose or glycerol were able to immediately use sucrose as a sole C source, suggesting that sucrose uptake and metabolism were constitutive. In contrast, glycerol uptake occurred preferentially in glycerol-grown cells. Independent of the preculture conditions, when sucrose and glycerol were added simultaneously to batch cultures, the sucrose was used first, and once the supply of sucrose was exhausted, the glycerol was consumed. Utilization of nitrate as an N source occurred without nitrite of ammonium accumulation when glycerol was used, but nitrite accumulated when sucrose was used. In chemostat cultures K. oxytoca CECT 4460 efficiently removed nitrate without accumulation of nitrite or ammonium when sucrose, glycerol, or mixtures of these two C sources were used. The growth yields and the efficiencies of C and N utilization were determined at different growth rates in chemostat cultures. Regardless of the C source, yield carbon (Y{sub C}) ranged between 1.3 and 1.0 g (dry weight) per g of sucrose C or glycerol C consumed. Regardless of the specific growth rate and the C source, yield nitrogen (Y{sub N}) ranged from 17.2 to 12.5 g (dry weight) per g of nitrate N consumed.

  16. Summary of Remediated Nitrate Salt Surrogate Formulation and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Geoffrey Wayne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Leonard, Philip [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hartline, Ernest Leon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tian, Hongzhao [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    High Explosives Science and Technology (M-7) completed all required formulation and testing of Remediated Nitrate Salt (RNS) surrogates on April 27, 2016 as specified in PLAN-TA9-2443 Rev B, "Remediated Nitrate Salt (RNS) Surrogate Formulation and Testing Standard Procedure", released February 16, 2016. This report summarizes the results of the work and also includes additional documentation required in that test plan. All formulation and testing was carried out according to PLAN-TA9-2443 Rev B. The work was carried out in three rounds, with the full matrix of samples formulated and tested in each round. Results from the first round of formulation and testing were documented in memorandum M7-J6-6042, " Results from First Round of Remediated Nitrate Salt Surrogate Formulation and Testing." Results from the second round of formulation and testing were documented in M7-16-6053 , "Results from the Second Round of Remediated Nitrate Salt Surrogate Formulation and Testing." Initial results from the third round were documented in M7-16-6057, "Initial Results from the Third Round of Remediated Nitrate Salt Formulation and Testing."

  17. Evaluating simultaneous chromate and nitrate reduction during microbial denitrification processes.

    Science.gov (United States)

    Peng, Lai; Liu, Yiwen; Gao, Shu-Hong; Chen, Xueming; Ni, Bing-Jie

    2016-02-01

    Sulfur-based autotrophic denitrification and heterotrophic denitrification have been demonstrated to be promising technological processes for simultaneous removal of nitrate NO3(-) and chromate (Cr (VI)), two common contaminants in surface and ground waters. In this work, a mathematical model was developed to describe and evaluate the microbial and substrate interactions among sulfur oxidizing denitrifying organism, methanol-based heterotrophic denitrifiers and chromate reducing bacteria in the biofilm systems for simultaneous nitrate and chromate removal. The concomitant multiple chromate reduction pathways by these microbes were taken into account in this model. The validity of the model was tested using experimental data from three independent biofilm reactors under autotrophic, heterotrophic and mixotrophic conditions. The model sufficiently described the nitrate, chromate, methanol, and sulfate dynamics under varying conditions. The modeling results demonstrated the coexistence of sulfur-oxidizing denitrifying bacteria and heterotrophic denitrifying bacteria in the biofilm under mixotrophic conditions, with chromate reducing bacteria being outcompeted. The sulfur-oxidizing denitrifying bacteria substantially contributed to both nitrate and chromate reductions although heterotrophic denitrifying bacteria dominated in the biofilm. The mixotrophic denitrification could improve the tolerance of autotrophic denitrifying bacteria to Cr (VI) toxicity. Furthermore, HRT would play an important role in affecting the microbial distribution and system performance, with HRT of higher than 0.15 day being critical for a high level removal of nitrate and chromate (over 90%). PMID:26619398

  18. Reduction of nitrate from groundwater: powder catalysts and catalytic membrane

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-xu; ZHANG Yan; LIU Hong-yuan

    2003-01-01

    The reduction of nitrate contaminant in groundwater has gained renewed and intensive attention due to the environmental problems and health risks. Catalytic denetrification presents one of the most promising approaches for the removal of nitrate from water. Catalytic nitrate reduction from water by powder catalysts and catalytic membrane in a batch reactor was studied. And the effects of the initial concentration, the amounts of catalyst, and the flux H2 on the nitrate reduction were also discussed. The results demonstrated that nitrate reduction activity and the selectivity to nitrogen gas were mainly controlled by diffusion limitations and the mass transfer of the reactants. The selectivity can improved while retaining a high catalytic activity under controlled diffusion condition or the intensification of the mass transfer, and a good reaction condition. The total nitrogen removal efficiency reached above 80%. Moreover, catalytic membrane can create a high effective gas/liquid/solid interface, and show a good selectivity to nitrogen in comparative with the powder catalyst, the selectivity to nitrogen was improved from 73.4% to 89.4%.

  19. Surface and groundwater Nitrate distribution in the area of Vicenza

    International Nuclear Information System (INIS)

    Public aqueducts in the Province of Vicenza (Italy) are supplied entirely by various kinds of water sources: the sub river bed strata of the mountain valleys, water-bearing aquifers of the high plan, pressurized water-bearing aquifers of the middle plain, karstic reservoirs of the mountain massifs and local springs. Progressive increase in nitrate concentration has long been detected in the underground water of many parts of the Vicenza region. The nitrates originate from various sources: human waste, industrial dumping (e.g. the tanning industry) and the use of animal and chemical fertilizers. Nitrate distribution was studied in all wells used for extracting underground water including source waters which replenishing underground aquifers. During the study period ('91-'95), water courses in the recharge areas were found to have nitrate concentrations ranging between 2.0 and 42.0 mg/l. These values remained substantially stable in time. Underground aquifers showed stable nitrate concentration between 5.0 mg/l (mountain karstic aquifers; sub-river bed strata of valley bottom) and 44.0 mg/l (water bearing strata of the high plain of Astico and Brenta rivers). The pressurized flooding aquifers of the middle plain have lower concentrations (6.0-21.0 mg/l) but tend to increase by about 0.5 mg/l per year

  20. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms.

    Science.gov (United States)

    Kutvonen, Heini; Rajala, Pauliina; Carpén, Leena; Bomberg, Malin

    2015-01-01

    We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using (15)N-based stable isotope probing (SIP) and enrichment with (14∕15)N-ammonium or (14∕15)N-nitrate complemented with methane. Twenty-eight days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG) gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG) from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium, and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. (15)N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used (15)N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system. PMID:26528251

  1. Sulfide elimination by intermittent nitrate dosing in sewer sediments

    Institute of Scientific and Technical Information of China (English)

    Yanchen Liu; Chen Wu; Xiaohong Zhou; David Z.Zhu; Hanchang Shi

    2015-01-01

    The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards,and requires expensive programs for its prevention.The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments.The study was carried out based on lab-scale experiments and batch tests using real sewer sediments.The intermittent nitrate dosing mode and the optimal control condition were investigated.The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment.The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions ofefficient sulfide control with lower carbon source loss.The opth-nal control condition is feasible for the sulfide elimination in sewer systems.

  2. Determination of Nitrate Reductase Assay Depending on the Microbial Growth

    International Nuclear Information System (INIS)

    A rapid micro-dilution assay for determination of the antimicrobial susceptibility of different bacterial isolates was developed. This assay is based on the ability of the most of viable organisms to reduce nitrates. The MIC or MBC could be determined by nitrate reductase (NR) only after 30 to 90 min of incubation depending on the behaviour of microbial growth. Bacterial viability is detected by a positive nitrite reduction rather than visible turbidity. The nitrate reduction assay was compared with standard micro-assay using 250 isolates of different taxa against 10 antibiotics belonging to different classes. An excellent agreement of 82.5 % was found between the two methods and only 17.5 % of 1794 trials showed difference in the determined MIC by tow-dilution interval above or below the MIC determined by the turbidimetric method under the same test conditions. However, the nitrate reduction assay was more rapid and sensitive in detecting viable bacteria and so, established an accurate estimate of the minimal inhibitory concentration (MIC) or the minimal bacterial concentration (MBC). The nitrate reduction assay offers the additional advantage that it could be used to determine the MBC without having to subculture the broth. 232 cases of resistance were detected by NR and 4 different media were tested for susceptibility test. The bacterial isolates were exposed to ultra violet (UV) light for different period

  3. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    Directory of Open Access Journals (Sweden)

    Heini eKutvonen

    2015-10-01

    Full Text Available We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP and enrichment with 14/15N-ammonium or 14/15N-nitrate complemented with methane. 28 days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. 15N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used 15N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system.

  4. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    Science.gov (United States)

    Kutvonen, Heini; Rajala, Pauliina; Carpén, Leena; Bomberg, Malin

    2015-01-01

    We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP) and enrichment with 14∕15N-ammonium or 14∕15N-nitrate complemented with methane. Twenty-eight days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG) gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG) from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium, and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. 15N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used 15N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system. PMID:26528251

  5. Sensitive Immunoassays of Nitrated Fibrinogen in Human Biofluids

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhiwen; Wu, Hong; Du, Dan; Wang, Jun; Wang, Hua; Qian, Weijun; Bigelow, Diana J.; Pounds, Joel G.; Smith, Richard D.; Lin, Yuehe

    2010-05-05

    Three new sandwich immunoassays for detection of nitrated biomarker have been established with potential applications in biomedical studies and clinical practice. In this study, nitrated human fibrinogen, a potential oxidative stress biomarker for several pathologies, was chosen as the target. To improve the sensitivity and overcome the interference caused by the complexity of human biofluids, we developed three sandwich strategies using various combinations of primary antibody and secondary antibody. All three strategies demonstrated high sensitivity and selectivity towards nitrated forms of fibrinogen in buffer, but their performances were dramatically reduced when tested with human plasma and serum samples. Systematically optimizations were carried out to investigate the effects of numerous factors, including sampling, coating, blocking, and immunoreactions. Our final optimization results indicate that two of these strategies retain sufficient sensitivity and selectivity for use as assays in human physiological samples. Specifically, detection limits reached the pM level and the linear response ranges were up to nM level with a correlation coefficient > 0.99. To our best knowledge, this is the first example of using an electrochemical immunoassay for a nitrated biomarker in a physiological fluid. This novel approach provides a rapid, sensitive, selective, cost efficient and robust bioassay for detection of oxidative stress in pathology and for clinical applications. Moreover, the sandwich strategies developed in this paper can be readily used to establish effective methods targeting other nitration biomarkers.

  6. Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry

    Directory of Open Access Journals (Sweden)

    A. L. Lockwood

    2010-04-01

    Full Text Available Isoprene is an important atmospheric volatile organic compound involved in ozone production and NOx (NO+NO2 sequestration and transport. Isoprene reaction with OH in the presence of NO can form either isoprene nitrates or convert NO to NO2 which can photolyze to form ozone. While it has been shown that isoprene nitrate production can represent an important sink for NOx in forest impacted environments, there is little experimental knowledge of the relative importance of the individual isoprene nitrate isomers, each of which has a different fate and reactivity. In this work, we have identified the 8 individual isomers and determined their total and individual production yields. The overall yield of isoprene nitrates at atmospheric pressure and 295 K was found to be 0.070(+0.025/–0.015. Three isomers, the (4,3-IN, (1,2-IN and Z-(4,1-IN represent 90% of the total IN yield. We also determined the ozone rate constants for three of the isomers, and have calculated their atmospheric lifetimes, which range from ~1–2 h, making their oxidation products likely more important as atmospheric organic nitrates and sinks for nitrogen.

  7. Removal of nitrate by electrodialysis in the presence of acetate

    International Nuclear Information System (INIS)

    In order to remove nitrate selectively from different salt-loaded water, we have studied the electrodialysis of a solution containing nitrate and acetate ions through an original ion exchange membrane. We have showed that NO3- was removed more effectively than CH3COO-. We realized electrodialysis of synthetic solutions containing first of all a single kind of anion, the ion nitrate or the ion acetate, and in the second place the mixture of both kinds of ions and at the same concentration. The ion-exchange membrane (MEA) was obtained from the company ERAS Labo [1], designed initially for use in alkaline fuel cells. We wanted to test its behavior for electrodialysis. The results show that this MEA behaves practically in the same way towards both kinds of ions when the solution contains only a single kind of anion, the migration rate being linked to the value of the current. But once the anions are mixed, we noticed that the migration of the ion nitrate of the central compartment into the anodic compartment was much faster than that of the ion acetate. NO3-migrating easily while the CH3COO- stops practically migrating during 10 min approximately of time of electrodialysis. This demonstrates a selectivity of this kind of membrane towards the anion nitrate. The ion mobility, the hydrated ionic radii as well as the conductivity of the ionic solution may influence the transfer through the utilized membrane.

  8. Nitrogen and carbon isotopes as tracers of nitrate in groundwater

    International Nuclear Information System (INIS)

    Nitrate continues to be a problem in New Zealand groundwater supplies. Major sources of nitrate are: mineralisation of soil nitrogen, fertilisers, animal manure (mainly urine) and septic wastes. Loss of ammonia during breakdown of urea causes enrichment in 15N, which in principle can be used to identify the resulting NO3. The authors have a continuous flow mass spectrometer which facilitates analysis of nitrogen and carbon isotopes in samples. Samples are freeze dried, loaded onto the elemental analyser and analysed for 15N and 13C automatically. Present work is looking at the effects of different pretreatments on results, and applying the method to groundwaters from the Bay of Plenty, Waimea Plains and Canterbury. Possible pretreatments may improve the specificity of the measurement; i.e. rather than analysing the total precipitate one may analyse a specific component. Oxidation is producing consistent results. Regular monitoring of groundwater wells is being carried out on the Waimea Plains to trace sources of nitrate. These are being compared with results from areas on the Canterbury Plains, where groundwater nitrate levels are elevated. At the same time CFC concentrations are being used to determine the residence times of the groundwaters sampled, to provide evidence on when the nitrate contamination took place and the time-variation of the contamination

  9. Hydrogen anode for nitrate waste destruction. Revision 2

    International Nuclear Information System (INIS)

    Large quantities of radioactive and hazardous wastes have been generated from nuclear materials production during the past fifty years. Processes are under evaluation to separate the high level radioactive species from the waste and store them permanently in the form of durable solids. The schemes proposed will separate the high level radioactive components, cesium-137 and strontium-90, into a small volume for incorporation into a glass wasteform. The remaining low-level radioactive waste contain species such as nitrites and nitrates that are capable of contaminating ground water. Electrochemical destruction of the nitrate and nitrite before permanent storage has been proposed. Not only will the electrochemical processing destroy these species, the volume of the waste could also be reduced. The use of a hydrogen gas-fed anode and an acid anolyte in an electrochemical cell used to destroy nitrate was demonstrated. A mixed Na2SO4/H2SO4 anolyte was shown to favor the nitrate cell performance, and the generation of a higher hydroxide ion concentration in the catholyte. The suggested scheme is an apparent method of sodium sulfate disposal and a possible means through which ammonia (to ammonium sulfate, fertilizer) and hydrogen gas could be recycled through the anode side of the reactor. This could result in a substantial savings in the operation of a nitrate destruction cell

  10. Optimizing Sampling Strategies for Riverine Nitrate Using High-Frequency Data in Agricultural Watersheds.

    Science.gov (United States)

    Reynolds, Kaycee N; Loecke, Terrance D; Burgin, Amy J; Davis, Caroline A; Riveros-Iregui, Diego; Thomas, Steven A; St Clair, Martin A; Ward, Adam S

    2016-06-21

    Understanding linked hydrologic and biogeochemical processes such as nitrate loading to agricultural streams requires that the sampling bias and precision of monitoring strategies be known. An existing spatially distributed, high-frequency nitrate monitoring network covering ∼40% of Iowa provided direct observations of in situ nitrate concentrations at a temporal resolution of 15 min. Systematic subsampling of nitrate records allowed for quantification of uncertainties (bias and precision) associated with estimates of various nitrate parameters, including: mean nitrate concentration, proportion of samples exceeding the nitrate drinking water standard (DWS), peak (>90th quantile) nitrate concentration, and nitrate flux. We subsampled continuous records for 47 site-year combinations mimicking common, but labor-intensive, water-sampling regimes (e.g., time-interval, stage-triggered, and dynamic-discharge storm sampling). Our results suggest that time-interval sampling most efficiently characterized all nitrate parameters, except at coarse frequencies for nitrate flux. Stage-triggered storm sampling most precisely captured nitrate flux when less than 0.19% of possible 15 min observations for a site-year were used. The time-interval strategy had the greatest return on sampling investment by most precisely and accurately quantifying nitrate parameters per sampling effort. These uncertainty estimates can aid in designing sampling strategies focused on nitrate monitoring in the tile-drained Midwest or similar agricultural regions. PMID:27192208

  11. Organic nitrate aerosol formation via NO3 + BVOC in the Southeastern US

    Science.gov (United States)

    Ayres, B. R.; Allen, H. M.; Draper, D. C.; Brown, S. S.; Wild, R. J.; Jimenez, J. L.; Day, D. A.; Campuzano-Jost, P.; Hu, W.; de Gouw, J.; Koss, A.; Cohen, R. C.; Duffey, K. C.; Romer, P.; Baumann, K.; Edgerton, E.; Takahama, S.; Thornton, J. A.; Lee, B. H.; Lopez-Hilfiker, F. D.; Mohr, C.; Goldstein, A. H.; Olson, K.; Fry, J. L.

    2015-06-01

    Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOC) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are calculated and correlated to gas and aerosol organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol as measured by Aerosol Mass Spectrometry (AMS) and Thermal Dissociation - Laser Induced Fluorescence (TD-LIF) suggests a range of molar yield of aerosol phase monoterpene nitrates of 23-44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to terpenes and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 0.5 % of the total organic nitrate in the aerosol-phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading comparable to that of organic nitrate produced via NO3 + BVOC.

  12. Organic nitrate aerosol formation via NO3 + biogenic volatile organic compounds in the southeastern United States

    Science.gov (United States)

    Ayres, B. R.; Allen, H. M.; Draper, D. C.; Brown, S. S.; Wild, R. J.; Jimenez, J. L.; Day, D. A.; Campuzano-Jost, P.; Hu, W.; de Gouw, J.; Koss, A.; Cohen, R. C.; Duffey, K. C.; Romer, P.; Baumann, K.; Edgerton, E.; Takahama, S.; Thornton, J. A.; Lee, B. H.; Lopez-Hilfiker, F. D.; Mohr, C.; Wennberg, P. O.; Nguyen, T. B.; Teng, A.; Goldstein, A. H.; Olson, K.; Fry, J. L.

    2015-12-01

    Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOCs) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that a nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are correlated with increase in gas- and aerosol-organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol formation as measured by aerosol mass spectrometry and thermal dissociation laser-induced fluorescence suggests a molar yield of aerosol-phase monoterpene nitrates of 23-44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to BVOCs and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate-oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 1 % of the total organic nitrate in the aerosol phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading at a rate comparable to that of organic nitrate produced via NO3 + BVOCs.

  13. Organic nitrate aerosol formation via NO3 + BVOC in the Southeastern US

    Directory of Open Access Journals (Sweden)

    B. R. Ayres

    2015-06-01

    Full Text Available Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOC and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013 in central Alabama show that nitrate radical (NO3 reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are calculated and correlated to gas and aerosol organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol as measured by Aerosol Mass Spectrometry (AMS and Thermal Dissociation – Laser Induced Fluorescence (TD-LIF suggests a range of molar yield of aerosol phase monoterpene nitrates of 23–44 %. Compounds observed via chemical ionization mass spectrometry (CIMS are correlated to predicted nitrate loss to terpenes and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 0.5 % of the total organic nitrate in the aerosol-phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading comparable to that of organic nitrate produced via NO3 + BVOC.

  14. Tropospheric measurements of nitric acid vapor and particulate nitrate

    International Nuclear Information System (INIS)

    Measurements of tropospheric nitric acid and particulate nitrate concentrations as a function of altitude in various marine and continental areas generally free from urban pollution are presented. Air was sampled at altitudes from 0.2 to 8 km, above and within the boundary layer, from 54 deg S to 70 deg N using impregnated filter technology. Most of the samples taken in the northern mid-latitude continental region are observed to contain greater than 0.1 ppbv nitric acid, while the rest of the samples contained significantly less. Particulate nitrate concentrations range from generally less than 0.2 ppbm above the boundary layer to 1.4 ppbm in the continental, urban-influenced boundary layer. Nitric acid is found to exceed particulate nitrate above the boundary layer, however to be considerably less in the marine boundary layer. Implications of these measurements for one-dimensional models of nitric acid gradients and global nitrogen oxide budgets are discussed

  15. Nitrate pollution of shallow ground water in chaj doab

    International Nuclear Information System (INIS)

    Chaj Doab is an interfluvial tract of land bounded by the rivers Chenab and Jhelum. Agriculture is the main economic activity in the area. In order to increase crop production,. natural and industrial fertilizers are excessively used. Shallow groundwater is the main source of water for domestic and agricultural usage. Nitrate in the soil is carried to the groundwater by precolating water. Concentration of nitrate in groundwater which used to be less than 3 mg/l has crossed the WHO limit of 45 mg/l at several places principally due to the excessive use of fertilizers. In order to avoid serious consequences of nitrate pollution of groundwater, application of fertilizers will have to be judiciously practiced. (author)

  16. Handling of Ammonium Nitrate Mother-Liquid Radiochemical Production - 13089

    International Nuclear Information System (INIS)

    The aim of the work is to develop a basic technology of decomposition of ammonium nitrate stock solutions produced in radiochemical enterprises engaged in the reprocessing of irradiated nuclear fuel and fabrication of fresh fuel. It was necessary to work out how to conduct a one-step thermal decomposition of ammonium nitrate, select and test the catalysts for this process and to prepare proposals for recycling condensation. Necessary accessories were added to a laboratory equipment installation decomposition of ammonium nitrate. It is tested several types of reducing agents and two types of catalyst to neutralize the nitrogen oxides. It is conducted testing of modes of the process to produce condensation, suitable for use in the conversion of a new technological scheme of production. It is studied the structure of the catalysts before and after their use in a laboratory setting. It is tested the selected catalyst in the optimal range for 48 hours of continuous operation. (authors)

  17. Agriculture causes nitrate fertilization of remote alpine lakes

    Science.gov (United States)

    Hundey, E. J.; Russell, S. D.; Longstaffe, F. J.; Moser, K. A.

    2016-02-01

    Humans have altered Earth's nitrogen cycle so dramatically that reactive nitrogen (Nr) has doubled. This has increased Nr in aquatic ecosystems, which can lead to reduced water quality and ecosystem health. Apportioning sources of Nr to specific ecosystems, however, continues to be challenging, despite this knowledge being critical for mitigation and protection of water resources. Here we use Δ17O, δ18O and δ15N from Uinta Mountain (Utah, USA) snow, inflow and lake nitrate in combination with a Bayesian-based stable isotope mixing model, to show that at least 70% of nitrates in aquatic systems are anthropogenic and arrive via the atmosphere. Moreover, agricultural activities, specifically nitrate- and ammonium-based fertilizer use, are contributing most (~60%) Nr, and data from other North American alpine lakes suggest this is a widespread phenomenon. Our findings offer a pathway towards more effective mitigation, but point to challenges in balancing food production with protection of important water resources.

  18. Nitrate in Danish groundwater during the last 60 years

    DEFF Research Database (Denmark)

    Hansen, B; Thorling, L; Dalgaard, Tommy;

    have succeeded in decreasing the N surplus by 40% since the mid 1980s while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate......This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis...... of distribution, trends and trend reversals in the groundwater nitrate concentration. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first...

  19. Bacteria-driven production of alkyl nitrates in seawater

    Science.gov (United States)

    Kim, Michelle J.; Michaud, Jennifer M.; Williams, Renee; Sherwood, Byron Pedler; Pomeroy, Robert; Azam, Farooq; Burkart, Michael; Bertram, Timothy H.

    2015-01-01

    and ship-borne measurements have shown that the ocean is a large, diffuse source for short chain (C1-C3) gas phase alkyl nitrates (RONO2). Photochemical production of RONO2 has been demonstrated previously as a viable mechanism in surface waters; however, it cannot account for the observed depth profile of RONO2, suggesting an additional, dark RONO2 production mechanism. We present measurements of gas phase C1-C5 alkyl nitrates emitted from seawater in a controlled mesocosm experiment conducted under low-light conditions in a glass-walled wave channel. Ethyl and butyl nitrate emission rates from seawater are strongly correlated with the abundance of heterotrophic bacteria (R2 ≥ 0.89) and show no correlation to chlorophyll a concentration. Controlled flask experiments conducted using ambient and sterile seawater, inoculated with a heterotrophic bacterium, confirm that bacterial driven production of select RONO2 can proceed efficiently in the absence of light.

  20. Mass-balance model for predicting nitrate in ground water

    Science.gov (United States)

    Frimpter, Michael H.; Donohue, John J.; Rapacz, Michael V.

    1990-01-01

    A mass-balance accounting model can be used to guide the management of septic systems and fertilizers to control the degradation of ground-water quality in zones of an aquifer that contribute water to public-supply wells. The nitrate concentration of the mixture in the well can be predicted for steady-state conditions by calculating the concentration that results from the total weight of nitrogen and total volume of water entering the zone of contribution to the well. These calculations will allow water-quality managers to predict the nitrate concentrations that would be produced by different types and levels of development, and to plan development accordingly. Computations for different development schemes provide a technical basis for planners and managers to compare water-quality effects and to select alternatives that limit nitrate concentration in wells.

  1. Isotopic compositions of sulphates and nitrates from the Chilean nitrate deposits, evidence for concentration and fractionation of parental brines

    International Nuclear Information System (INIS)

    Isotopic compositions of nitrates (δ15N and δ18O) in caliche samples from the Chilean nitrate deposits are similar to recent values reported for nitrate associated to atmospheric N deposition. δ34S and δ18O of sulphate minerals present in the nitrate ores show similar values to those of continental evaporites in the area of Atacama, which suggest volcanic and hydrothermal sources. The sulphate isotope compositions display positive correlation trends (between δ34S and δ18OSO4) reflecting a reservoir effect due to fractionation related to precipitation. This effect has been clearly observed for sulphur and oxygen from sedimentary to bedrock caliche samples. Ore-grade bedrock caliche (mostly nitratine-halite mixtures filling veins) shows lower δ34S and δ18O values than sedimentary caliche (acting as wall rock). This suggests the concentration and fractionation of brines by repeated processes of evaporation and precipitation. Saline compounds of different origins present in the Neogene Atacama Desert were transported by the hydrological system towards the lower endorheic areas. As a result, saline minerals (mostly nitrates, chlorides and sulphates) precipitated filling the porosity and fractures of previous rocks (author)

  2. Optimization of a uranyl nitrate passive neutron counter

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, Eric Benton [Los Alamos National Laboratory; Bracken, David [Los Alamos National Laboratory; West, James [Los Alamos National Laboratory; Freeman, Corey [Los Alamos National Laboratory; Newell, Matthew R [Los Alamos National Laboratory; Bourret, Steven C [Los Alamos National Laboratory; Rothrock, Richard B [Los Alamos National Laboratory; Ladd - Lively, Jennifer L [ORNL; Schuh, Denise [ORNL

    2010-01-01

    Safeguarding natural uranium as it enters the fuel cycle has become a priority for the safeguards community in recent years. Uranyl nitrate is a material of interest in this endeavor because it is normally a step in the process from converting uranium ores to more concentrated forms like UO{sub 2} and U{sub 3}O{sub 8}. This paper will detail the improvements and design optimizations made for a uranyl nitrate neutron detector. The original design of the detector was based on standard neutron counter designs and featured 2 rings of He-3 tubes fully moderated and shielded from background. Several areas for enhancement were identified after months of testing in three different locations. An operating uranyl nitrate facility was included as one of the test locations. Three significant upgrades to the counter addressed in the redesign were: real time background detection, counter reliability improvements, and optimization of the detector design for the detection of neutrons emitted by the uranyl nitrate flowing through the monitored process pipe. The optimized detector design includes significant electronics upgrades, the ability to detect neutrons (background and signal) with 36 degree spatial resolution around the process pipe for signal and 45 degree spatial resolution for background, inner and outer rings of He-3 tubes for real time background corrections, and notably more reliable cabling. Monte Carlo N-Particle (MCNP) modeling was used to optimize the signal (neutrons from uranyl nitrate in the monitored process pipe) to noise (background neutrons from all sources) ratio of the inner ring of He-3 tubes. Additionally, MCNP modeling maximized noise to signal on the outer ring of He-3 tubes. Details of the detector optimization as well as all the additional detector enhancements will be discussed. The neutron counter will be field tested on the Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory (ORNL).

  3. The pollution of water by nitrates of chemical fertilizers

    International Nuclear Information System (INIS)

    The following article is a literature review that summarizes results from field studies devoted to chemical analysis of water in Lebanon. Agricultural practices and the use of fertilizers may affect surface waters, ground water and drinking water. Much attention has been given to their environmental consequences, especially those related to water pollution by Nitrates and human health. The Nitrate content should not exceed in drinking water more than 50 mg/l for adults and 25 mg/l for children and pregnant women. Studies suggest incorporation of quick remedial measures to combat pollution in marine environments

  4. Estimated Dietary Intake of Nitrite and Nitrate in Swedish Children

    OpenAIRE

    Larsson, Kristin Anna; Darnerud, Per Ola; Ilbäck, Nils-Gunnar; Merino, Leonardo

    2011-01-01

    Abstract This study examined the intake of nitrate and nitrite in Swedish children. Daily intake estimates were based on a nationwide food consumption survey (4-day food diary) and nitrite/nitrate content in vegetables, fruit, cured meat and water. The mean intake of nitrite from cured meat among 2259 children studied was 0.013, 0.010 and 0.007 mg kg-1 body weight day-1 in age groups 4, 8-9 and 11-12, respectively. Among these age groups, three individuals (0.1% of the studied chil...

  5. Effect of vanadium on nitrate reductase activity in tomato leaves

    OpenAIRE

    J. Buczek

    2015-01-01

    The activity of nitrate reductase in cell-free extracts from tomato leaves is completely inhibited by 100 μM NaVO3 or VOCl2. In experiments in vivo vanadium ions inhibit the activity of the enzyme in 50 to 60 per cent. Addition of l mM vanadium to the medium on which tomato seedlings are grown causes after 24 h almost complete inhibition of nitrate reductase activity in cell-free extracts of the enzyme. Inhibition with vanadium may be abolished in experiments in vitro if the extract is treate...

  6. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    OpenAIRE

    Kutvonen, Heini; Rajala, Pauliina; Carpén, Leena; Bomberg, Malin

    2015-01-01

    We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP) and enrichment with 14∕15N-ammonium or 14∕15N-nitrate complemented with methane. Twenty-eight days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG) gene copies in the substrate amended microcosms simultaneously with...

  7. Transport of nitrate from a large cement based waste form

    International Nuclear Information System (INIS)

    A finite-element model is used to calculate the time-dependent transport of nitrate from a cement-based (saltstone) monolith with and without a clay cap. Model predictions agree well with data from two lysimeter field experiments begun in 1984. The clay cap effectively reduces the flux of nitrate from the monolith. Predictions for a landfill monolith design show a peak concentration occurring within 25 years; however, the drinking water guideline is exceeded for 1200 years. Alternate designs and various restrictive liners are being considered

  8. Conversion of uranium oxide into nitrate with nitrogen dioxide

    International Nuclear Information System (INIS)

    In order to decrease the amount of aqueous liquid waste discharged from nuclear fuel reprocessing, the conversion of uranium dioxide into its nitrate using liquefied nitrogen dioxide was studied. Uranium dioxide powder was immersed in liquefied nitrogen dioxide at 313 K after a pretreatment by the oxidation of the uranium dioxide with nitrogen dioxide and air at 523 K. Seventy-nine % of the uranium dioxide, whose initial feed amount was 0.3 g, was converted into a water soluble compound. Based on an XRD analysis, uranyl nitrate trihydrate (UO2(NO3)2)·3H2O) was confirmed as the product. (author)

  9. Method of processing radioactive liquid waste containing soduium nitrate

    International Nuclear Information System (INIS)

    Sulfuric acid is added to radioactive liquid wastes containing sodium nitrate and heated to convert sodium nitrate into sodium sulfate and remove nitric acid as fumes. Then, calcium oxide or calcium hydroxide is added to the resultant liquid wastes containing sodium sulfate into a solution of calcium sulfate and sodium hydroxide. Then, solid-liquid separation is applied to take out, as a solid, calcium sulfate containing most portion of radioactive materials. Since no burnable materials such as asphalt are not used as in the prior art method, it is possible, according to the present invention, to reduce the fire hazard and remarkably decrease the formation of solidification products. (S.T.)

  10. Retour "écologique" sur la question des nitrates

    OpenAIRE

    Buson, Christian

    2012-01-01

    Un examen critique de la question des nitrates est proposé dans cet article, à la lumière des connaissances disponibles dans différentes disciplines. Au plan sanitaire, la norme sur l’eau potable établie depuis plusieurs décennies résulte d’une erreur ancienne aujourd’hui reconnue comme telle. Les nitrates n’engendrent aucun trouble sanitaire et les griefs tels que la méthémoglobinémie du nourrisson, ou le risque de cancer du à la formation de nitrosamines, qui les ont...

  11. Nitrate leaching following cultivation of contrasting temporary grassland.

    OpenAIRE

    Eriksen, J.; Søegaard, K.

    2000-01-01

    The N-surplus in grazed grassland is much higher than in cut grassland. Therefore, the residual effects of three years of temporary grassland on nitrate leaching in the following cereal crop were determined. Grassland managements were either cut leys or grazing with dairy cows in both pure grass and grass-clover mixtures. The cows were fed two levels of N in the supplements. Grassland management had little effect on the subsequent nitrate leaching, which ranged from 6 to 36 kg N ha-1, even th...

  12. Effects of potassium nitrate on the solid phase transitions of ammonium nitrate particles

    Science.gov (United States)

    Wu, Hong Bo; Chan, Chak K.

    Ammonium nitrate (NH 4NO 3) is a common constituent of atmospheric particulate pollutants. It exists in five stable polymorphic forms, designated as phases V, IV, III, II and I, below its melting point of 170 °C. In atmospheric research, very little attention has been paid to the solid phase transitions of NH 4NO 3 because phase IV NH 4NO 3 particles are stable over a wide range of tropospheric temperatures. Potassium nitrate (KNO 3) is often found to co-exist with NH 4NO 3 in atmospheric aerosols, and it can change the phase transition behaviors of solid NH 4NO 3 particles. In this study, we investigated the effects of KNO 3 on the solid phase transitions of NH 4NO 3 particles using in situ microscopic Raman spectroscopy. Both the transition path and transition temperature of NH 4NO 3 single particles (40-700 μm) depend on the KNO 3 mass percentage and the particle size. With the addition of KNO 3, the IV→II transition, which appears at 52 °C for pure NH 4NO 3 particles, is replaced by the IV→III transition. The KNO 3 mass percentage required for this change in transition path increases with decreasing particle size and the transition temperature decreases with increasing KNO 3 mass percentage. At a relatively high mass percentage of KNO 3 (⩾7.4 wt%), the KNO 3/NH 4NO 3 mixed particles undergo the IV→III transition under ambient temperatures, or even crystallize directly in phase III from droplets with a further increase in the mass percentage of KNO 3. Submicron KNO 3/NH 4NO 3 particles crystallize to phase IV at low KNO 3 mass percentages (⩽5.7 wt%) but to phase III at higher KNO 3 mass percentages (⩾7.4 wt%). These results suggest that atmospheric solid NH 4NO 3 particles may exist in phase III and the phase transitions should not be ignored in atmospheric chemical models.

  13. Effect of nitrate, organic carbon, and temperature on potential denitrification rates in nitrate-rich riverbed sediments

    Science.gov (United States)

    Pfenning, K.S.; McMahon, P.B.

    1997-01-01

    A study conducted in 1994 as part of the US Geological Survey's National Water-Quality Assessment Program, South Platte River Basin investigation, examined the effect of certain environmental factors on potential denitrification rates in nitrate-rich riverbed sediments. The acetylene block technique was used to measure nitrous oxide (N2O) production rates in laboratory incubations of riverbed sediments to evaluate the effect of varying nitrate concentrations, organic carbon concentrations and type, and water temperature on potential denitrification rates. Sediment incubations amended with nitrate, at concentrations ranging from 357 to 2142 ??mol l-1 (as measured in the field), produced no significant increase (P > 0.05) in N2O production rates, indicating that the denitrification potential in these sediments was not nitrate limited. In contrast, incubations amended with acetate as a source of organic carbon, at concentrations ranging from 0 to 624 ??mol l-1, produced significant increases (P organic carbon concentration, indicating that the denitrification potential in these sediments was organic carbon limited. Furthermore, N2O production rates also were affected by the type of organic carbon available as an electron donor. Acetate and surface-water-derived fulvic acid supported higher N2O production rates than groundwater-derived fulvic acid or sedimentary organic carbon. Lowering incubation temperatures from 22 to 4??C resulted in about a 77% decrease in the N2O production rates. These results help to explain findings from previous studies indicating that only 15-30% of nitrate in groundwater was denitrified before discharging to the South Platte River and that nitrate concentrations in the river generally were higher in winter than in summer.

  14. Oxygen and nitrogen isotopic composition of nitrate in commercial fertilizers, nitric acid, and reagent salts.

    Science.gov (United States)

    Michalski, Greg; Kolanowski, Michelle; Riha, Krystin M

    2015-01-01

    Nitrate is a key component of synthetic fertilizers that can be beneficial to crop production in agro-ecosystems, but can also cause damage to natural ecosystems if it is exported in large amounts. Stable isotopes, both oxygen and nitrogen, have been used to trace the sources and fate of nitrate in various ecosystems. However, the oxygen isotope composition of synthetic and organic nitrates is poorly constrained. Here, we present a study on the N and O isotope composition of nitrate-based fertilizers. The δ(15)N values of synthetic and natural nitrates were 0 ± 2 ‰ similar to the air N2 from which they are derived. The δ(18)O values of synthetic nitrates were 23 ± 3 ‰, similar to air O2, and natural nitrate fertilizer δ(18)O values (55 ± 5 ‰) were similar to those observed in atmospheric nitrate. The Δ(17)O values of synthetic fertilizer nitrate were approximately zero following a mass-dependent isotope relationship, while natural nitrate fertilizers had Δ(17)O values of 18 ± 2 ‰ similar to nitrate produced photochemically in the atmosphere. These narrow ranges of values can be used to assess the amount of nitrate arising from fertilizers in mixed systems where more than one nitrate source exists (soil, rivers, and lakes) using simple isotope mixing models. PMID:26181213

  15. Uranous nitrate production for Purex process applications using PtO2 catalyst and hydrazine nitrate as reductant

    International Nuclear Information System (INIS)

    In spent fuel reprocessing by Purex process uranium and plutonium are extracted together in the solvent 30% TBP-dodecane to effect decontamination from fission products and trivalent actinides. In a subsequent partition step, uranium and plutonium are separated from each other by selectively reducing Pu(IV) to Pu(III) in which valency it is least extractable in the above solvent. The reduction of Pu(IV) to Pu(III) is accomplished with the reducing agent uranous nitrate, which is produced conventionally by electrolytic reduction of U(VI) with hydrazine nitrate as uranous nitrate stabilizer. In this method of reduction the percentage conversion attainable is only 50 to 60%. The use of this solution as partitioning agent leads not only to the dilution of the plutonium product but also to increase in uranium processing load by each externally fed uranous nitrate batch. Also the oxide coating of the anode, TSIA (Titanium Substrate Insoluble Anode) wears out after a certain period of operation. This necessitates recoating which is quite cumbersome considering the amount of the decontamination involved. So an alternative to the conventional electrolytic method has been explored in the laboratory at FRD. It is observed that quantitative reduction of uranyl nitrate to uranous nitrate can be achieved with hydrazine nitrate as reductant in presence of PtO2 catalyst. Extensive laboratory scale studies were carried out to optimize the various parameters for quantitative reduction. The optimum parameters for the reduction of 4 grams of uranyl ions as a single batch (20 ml) with a catalyst amount of 320 milligrams are H+ 1 M, N2H2+ = 1.0 M and temperature = 60 degC and the time for quantitative reduction under these optimized conditions was 60 minutes. These studies were then extended to pilot plant scale and the catalyst amount used in these in studies was 80 grams. When the column was operated under the optimized conditions, the uranous production per single batch (10 litres

  16. Extraction of nitrates of lanthanoids (3) of the yttrium group and yttrium (3) by trialkylbenzylammonium nitrate in toluene

    International Nuclear Information System (INIS)

    A study was made on extraction of nitrates of lanthanoids (3) of the yttrium group (terbium-lutetium) and yttrium (3) by trialkylbensylammonium nitrate in toluene at T=298.15 K pH 2. Extraction isotherms are described with account of formation of compound of (R4N)2[Ln(NO3)5] composition in organic phase. Values of extraction constants decreasing in terbium (3)-lutetium (3) series, were calculated. Value of extraction constant for yttrium (3) is close to the value of extraction constant for ytterbium (3). 13 refs., 2 figs., 3 tabs

  17. The dysprosium nitrate-carbamide-water and the holmium nitrate-carbamide-water systems at 30 deg C

    International Nuclear Information System (INIS)

    Dysprosium nitrate-carbamide-water(1) and holmium nitrate-carbamide-water(2) systems are studied at 30 deg C by the solubility method. In both systems formed are incongruently soluble compounds of Dy(NO3)3x3CON2H4, Ho(NO3)3x3CON2H4 composition and congruently soluble ones of Dy(NO3)3x4CON2H4, Ho(NO3)3x4CON2H4 composition. Presented are solubility diagrams of the systems

  18. Identification and structure of the nasR gene encoding a nitrate- and nitrite-responsive positive regulator of nasFEDCBA (nitrate assimilation) operon expression in Klebsiella pneumoniae M5al.

    OpenAIRE

    Goldman, B. S.; Lin, J. T.; Stewart, V

    1994-01-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources through the nitrate assimilatory pathway. The structural genes for assimilatory nitrate and nitrite reductases together with genes necessary for nitrate transport form an operon, nasFEDCBA. Expression of the nasF operon is regulated both by general nitrogen control and also by nitrate or nitrite induction. We have identified a gene, nasR, that is necessary for nitrate and nitrite induction. The nasR gene, located immed...

  19. Anaerobic BTEX biodegradation linked to nitrate and sulfate reduction

    International Nuclear Information System (INIS)

    Effective anaerobic BTEX biodegradation was obtained under nitrate and sulfate reducing conditions by the mixed bacterial consortium that were enriched from gasoline contaminated soil. Under the conditions of using nitrate or sulfate as reducing acceptor, the degradation rates of the six tested substrates decreased with toluene > ethylbenzene > m-xylene > o-xylene > benzene > p-xylene. The higher concentrations of BTEX were toxic to the mixed cultures and led to reduce the degradation rates of BTEX. Benzene and p-xylene were more toxic than toluene and ethylbenzene. Nitrate was a more favorable electron acceptor compared to sulfate. The measured ratios between the amount of nitrate consumed and the amount of benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene degraded were 9.47, 9.26, 11.14, 12.46, 13.36 and 13.02, respectively. The measured ratios between sulfate reduction and BTEX degradation were 3.51, 4.33, 4.89, 4.81, 4.86 and 4.76, respectively, which were nearly the same to theoretical ones, and the relative error between the measured and calculated ratios was less than 10%

  20. Abuse of silver-nitrate solution for planing periorbital folds.

    Science.gov (United States)

    Schepler, Hadrian; Kessler, Jens; Hartmann, Bernd

    2002-02-01

    When using a Hollensteinstift to treat periorbital folds a 28-year-old female patient perceived a chemical burn of the lower lids and the periorbital regions. The initial treatment was frequent washing with soap solution and topical panthenol ointment. This unusual case is demonstrated to show the risks of improper use of silver-nitrate solution and to discuss therapeutic options. PMID:11834338

  1. Intrinsic hydration of monopositive uranyl hydroxide, nitrate, and acetate cations.

    Science.gov (United States)

    Chien, Winnie; Anbalagan, Victor; Zandler, Melvin; Van Stipdonk, Michael; Hanna, Dorothy; Gresham, Garold; Groenewold, Gary

    2004-06-01

    The intrinsic hydration of three monopositive uranyl-anion complexes (UO(2)A)(+) (where A = acetate, nitrate, or hydroxide) was investigated using ion-trap mass spectrometry (IT-MS). The relative rates for the formation of the monohydrates [(UO(2)A)(H(2)O)](+), with respect to the anion, followed the trend: Acetate > or = nitrate > hydroxide. This finding was rationalized in terms of the donation of electron density by the strongly basic OH(-) to the uranyl metal center, thereby reducing the Lewis acidity of U and its propensity to react with incoming nucleophiles, viz., H(2)O. An alternative explanation is that the more complex acetate and nitrate anions provide increased degrees of freedom that could accommodate excess energy from the hydration reaction. The monohydrates also reacted with water, forming dihydrates and then trihydrates. The rates for formation of the nitrate and acetate dihydrates [(UO(2)A)(H(2)O)(2)](+) were very similar to the rates for formation of the monohydrates; the presence of the first H(2)O ligand had no influence on the addition of the second. In contrast, formation of the [(UO(2)OH)(H(2)O)(2)](+) was nearly three times faster than the formation of the monohydrate. PMID:15144967

  2. Gamma ray induced decomposition of some solid nitrates

    International Nuclear Information System (INIS)

    Radiation induced decomposition of several inorganic nitrate salts has been studied. G(NO2-) is affected by cation valency and hydration molecules. For Bi(NO3)3.5H2O, G(NO2-) decreases exponentially with total absorbed dose but the total amount of NO-m2- varies linearly with increasing dose. Mechanism of decomposition is discussed. (author)

  3. Increase of water resistance of ammonium nitrate explosives

    Directory of Open Access Journals (Sweden)

    Zulkhair Mansurov

    2012-03-01

    Full Text Available Developed a method of kapsulating of ammonium nitrate with liquid paraffin increase finding explosives in water for 60 minutes. Placing explosives in the plastic shell, the explosive was, as in standing or running water during the day. When conducting field tests failures were absent.

  4. Electrocatalytic reduction of nitrate and selenate by NapAB.

    Science.gov (United States)

    Gates, Andrew J; Butler, Clive S; Richardson, David J; Butt, Julea N

    2011-01-01

    Bacterial cellular metabolism is renowned for its metabolic diversity and adaptability. However, certain environments present particular challenges. Aerobic metabolism of highly reduced carbon substrates by soil bacteria such as Paracoccus pantotrophus presents one such challenge since it may result in excessive electron delivery to the respiratory redox chain when compared with the availability of terminal oxidant, O2. The level of a periplasmic ubiquinol-dependent nitrate reductase, NAP, is up-regulated in the presence of highly reduced carbon substrates. NAP oxidizes ubiquinol at the periplasmic face of the cytoplasmic membrane and reduces nitrate in the periplasm. Thus its activity counteracts the accumulation of excess reducing equivalents in ubiquinol, thereby maintaining the redox poise of the ubiquinone/ubiquinol pool without contributing to the protonmotive force across the cytoplasmic membrane. Although P. pantotrophus NapAB shows a high level of substrate specificity towards nitrate, the enzyme has also been reported to reduce selenate in spectrophotometric solution assays. This transaction draws on our current knowledge concerning the bacterial respiratory nitrate reductases and extends the application of PFE (protein film electrochemistry) to resolve and quantify the selenate reductase activity of NapAB. PMID:21265780

  5. UNCERTAINTY AND THE REGULATION OF NITRATE POLLUTION FROM AGRICULTURE

    OpenAIRE

    Abrahams, Nii Adote; Shortle, James S.

    1997-01-01

    A simulation of U.S. corn production compares four environmental policies for controlling agricultural nitrate pollution. Public uncertainty about key economic parameters are considered. Results indicate that policy choice is sensitive to commodity programs and the public information structure. Agricultural research benefits are also sensitive to agricultural environmental policy choices.

  6. Aqueous Nitrate Recovery Line at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Finstad, Casey Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-15

    This powerpoint is part of the ADPSM Plutonium Engineering Lecture Series, which is an opportunity for new hires at LANL to get an overview of work done at TA55. It goes into detail about the aqueous nitrate recovery line at Los Alamos National Laboratory.

  7. Identifying Efficient Nitrate Reduction Strategies in the Upper Danube

    Directory of Open Access Journals (Sweden)

    Angel Udias

    2016-08-01

    Full Text Available Nitrogen losses in the form of Nitrate (N-NO3 from point and diffuse sources of pollution are recognized to be the leading cause of water body impairment throughout Europe. Implementation of conservation programs is perceived as being crucial for restoring and protecting the good ecological status of freshwater bodies. The success of conservation programs depends on the efficient identification of management solutions with respect to the envisaged environmental and economic objectives. This is a complex task, especially considering that costs and effectiveness of conservation strategies depend on their locations. We applied a multi-objective, spatially explicit analysis tool, the R-SWAT-DM framework, to search for efficient, spatially-targeted solution of Nitrate abatement in the Upper Danube Basin. The Soil Water Assessment Tool (SWAT model served as the nonpoint source pollution estimator for current conditions as well as for scenarios with modified agricultural practices and waste water treatment upgrading. A spatially explicit optimization analysis that considered point and diffuse sources of Nitrate was performed to search for strategies that could achieve largest pollution abatement at minimum cost. The set of optimal spatial conservation strategies identified in the Basin indicated that it could be possible to reduce Nitrate loads by more than 50% while simultaneously provide a higher income.

  8. Pollution par les nitrates: quels remèdes?

    OpenAIRE

    Zilliox, Lothaire; Schenck, Charles; Kobus, Helmut; Huwe, Bernd

    1990-01-01

    Au cours des dix dernières années, la pollution des eaux souterraines par les nitrates n'a cessé d'augmenter. Principale accussée: l'agriculture, l'application de méthodes de techniques culturales devrait permettre une meilleure gestion des engrais azotés.

  9. Electrosynthesis of 3-Nitrophenotiazine. Nitration in Non-Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    P. A. Perlo

    2000-03-01

    Full Text Available The nitration of Phenothiazine (PHEN in acetonitrile (ACN in the presence of excess NaNO2 has been studied in detail. First, the electrochemical behavior of the reactants was investigated by cyclic voltammetry to determine the electrolysis conditions. Controlledpotential electrolysis was used for the electrosynthesis.

  10. Bone and lung tumor response following inhalation of transuranic nitrates

    International Nuclear Information System (INIS)

    Eight-hundred five rats exposed to transuranic nitrate aerosols developed 111 lung tumors and 24 bone tumors. Results for 239Pu(NO3)4, 238Pu(NO3)4, and 253Es(NO3)3 were similar, and comparable to what has been shown for the more refractory transuranic oxides

  11. Role Playing and Mind Mapping Issues on Nitrate Contamination.

    Science.gov (United States)

    Pan, W. L.

    1996-01-01

    Presents mind-mapping and role-playing exercises designed to guide students in the exploration, expression, and integration of varying viewpoints and opinions of a controversial topic (nitrate contamination of water supply); illustrate the importance of applying soil fertility principles to environmental and agronomic management; and encourage…

  12. Optimizing nitrate removal in woodchip beds treating aquaculture effluents

    DEFF Research Database (Denmark)

    von Ahnen, Mathis; Pedersen, Per Bovbjerg; Hoffmann, Carl Christian;

    2016-01-01

    Nitrate is typically removed from aquaculture effluents using heterotrophic denitrification reactors. Heterotrophic denitrification reactors, however, require a constant input of readily available organic carbon (C) sources which limits their application in many aquaculture systems for practical ...... as it presents an alternative method for removing nitrates from aquaculture effluents especially for less intensive fish farms. Furthermore, it shows how this method can be optimized to yield higher removal rates of nitrate.......Nitrate is typically removed from aquaculture effluents using heterotrophic denitrification reactors. Heterotrophic denitrification reactors, however, require a constant input of readily available organic carbon (C) sources which limits their application in many aquaculture systems for practical...... (HCO3 -) inlet concentration (0.50-1.59 g HCO3 -/l) on the removal rate of NO3 -N, and additional organic and inorganic nutrients, in effluent deriving from an experimental recirculating aquaculture system (RAS).Volumetric NO3 -N removal rates ranged from 5.20 ± 0.02 to 8.96 ± 0.19 g/m3/day and were...

  13. electrocatalytic nitrate reduction on palladium based catalysts activated with germanium

    NARCIS (Netherlands)

    Gootzen, J.F.E.; Lefferts, L.; Veen, van J.A.R.

    1999-01-01

    The electrocatalytic reduction of nitrate has been studied with electrochemical methods on palladium and palladium–platinum electrodes activated with germanium. The formation of a palladium–germanium alloy that occurs at germanium coverage above 0.2 has a strong enhancing effect on the rate of nitra

  14. Radiation chemical dosimetry by means of nitrate-nitrite

    International Nuclear Information System (INIS)

    The different chemical systems used in dosimetry and the selection criteria for them are described. The general topics in dosimetry with alkali nitrates as well as the phenomena occurring in their radiolysis are also treated. The possibility of application in dosimetric areas useful in radiosterilization and industrial processes is studied too. (Author) 22 refs

  15. In-Field Bioreactor for Removing Nitrate from Tile Drainage

    Science.gov (United States)

    Nitrate in water leaving subsurface drain ('tile') systems often exceeds the 10 mg-N L-1 maximum contaminant level (MCL) set by the U.S. EPA for drinking water and has been implicated in contributing to the hypoxia problem within the Gulf of Mexico. Much of the NO3 from agricultural lands impacting ...

  16. Improving N credit predictions to reduce residual nitrate

    Science.gov (United States)

    The potential to increase farm profitability and reduce nitrate leaching in Minnesota are huge if the alfalfa N credit was better understood and applied to first-year corn. If the N credit (150 lb/N/ac) were applied to the nearly 250,000 acres of corn following alfalfa in Minnesota each year, 19,000...

  17. Radiation chemical dosimetry by means of nitrate-nitrite

    International Nuclear Information System (INIS)

    The different chemical systems used in dosimetry and the selection criteria for them are described. The general topics in dosimetry with alkali nitrates as well as the phenomena occurring in their radiolisis are also treated. The possibility of application in dosimetric areas useful in radiosterilization and industrial processes is studied too. (author)

  18. Destruction of nitrates, organics, and ferrocyanides by hydrothermal processing

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.M.; Foy, B.R.; Dell`Orco, P.C.; Anderson, G.; Archuleta, F.; Atencio, J.; Breshears, D.; Brewer, R.; Eaton, H.; McFarland, R.; McInroy, R.; Reynolds, T.; Sedillo, M.; Wilmanns, E.; Buelow, S.J.

    1993-03-01

    This work targets the remediation of the aqueous mixed wastes stored in the underground tanks at the Department of Energy site in Hanford, Washington via hydrothermal processing. The feasibility of destroying the nitrate, organic, and ferrocyanide components of the wastes under supercritical and near critical conditions (623 {degree}K to 873{degree}K, 22.1 MPa to 103.4 MPa) is addressed. A novel method was developed for determining the solubility of nitrate salts in supercritical water solutions at pressures ranging from 24.8 MPa to 30.3 MPa (3600 psi to 4400 psi) and temperatures from 723 {degree}K to 798 {degree}K. Sodium nitrate solubilities ranged from 293 mg/kg at 24.8 MPa and 798 {degree}K to 1963 mg/kg at 30.3 MPa and 723{degree}K. Solubility was found to vary directly with pressure, and inversely with temperature. An empirical relationship was developed for the estimation of sodium nitrate solubility at water densities between 0.08 and 0.16 kg/L and temperatures between 723{degree}K and 798{degree}K. A small volume batch reactor equipped with optical diagnostics was used to monitor the phase behavior of a diluted variant of a tank 101-SY simulant. Preliminary results suggest that a single phase is formed at 83 MPa at 773 {degree}K.

  19. Destruction of nitrates, organics, and ferrocyanides by hydrothermal processing

    International Nuclear Information System (INIS)

    This work targets the remediation of the aqueous mixed wastes stored in the underground tanks at the Department of Energy site in Hanford, Washington via hydrothermal processing. The feasibility of destroying the nitrate, organic, and ferrocyanide components of the wastes under supercritical and near critical conditions (623 degree K to 873 degree K, 22.1 MPa to 103.4 MPa) is addressed. A novel method was developed for determining the solubility of nitrate salts in supercritical water solutions at pressures ranging from 24.8 MPa to 30.3 MPa (3600 psi to 4400 psi) and temperatures from 723 degree K to 798 degree K. Sodium nitrate solubilities ranged from 293 mg/kg at 24.8 MPa and 798 degree K to 1963 mg/kg at 30.3 MPa and 723 degree K. Solubility was found to vary directly with pressure, and inversely with temperature. An empirical relationship was developed for the estimation of sodium nitrate solubility at water densities between 0.08 and 0.16 kg/L and temperatures between 723 degree K and 798 degree K. A small volume batch reactor equipped with optical diagnostics was used to monitor the phase behavior of a diluted variant of a tank 101-SY simulant. Preliminary results suggest that a single phase is formed at 83 MPa at 773 degree K

  20. Separation of 228Ra (Ms Th 1) from thorium nitrate

    International Nuclear Information System (INIS)

    Treatment of 135 kg of thorium nitrate (purified and recrystallized in 1958) has been made for extraction of 228Ra in equilibrium. Elimination of the preponderant part of thorium by solvent extraction (TBP) and last purification by chromatography (Dowex 50 W X 8 and 1 X 8). Total yield was about (38 ± 4) per cent. (authors)

  1. Nitrite-Responsive Activation of the Nitrate Assimilation Operon in Cyanobacteria Plays an Essential Role in Up-Regulation of Nitrate Assimilation Activities under Nitrate-Limited Growth Conditions

    OpenAIRE

    Aichi, Makiko; Maeda, Shin-Ichi; Ichikawa, Kazuhiro; Omata, Tatsuo

    2004-01-01

    NtcB of the cyanobacterium Synechococcus elongatus strain PCC 7942 is a LysR family protein that enhances expression of the nitrate assimilation operon (nirA operon) in response to the presence of nitrite, an intermediate of assimilatory nitrate reduction. Inactivation of ntcB in this cyanobacterium specifically abolishes the nitrite responsiveness of nirA operon expression, but under nitrate-replete conditions (wherein negative feedback by intracellularly generated ammonium prevails over the...

  2. Spatially distributed nitrate reduction potential in the saturated zone in till areas

    DEFF Research Database (Denmark)

    Hansen, Anne Lausten

    The topic of this PhD study was modeling of spatially distributed nitrate transport and reduction at catchment scale, which is of interest in order to delineate so-called nitrate sensitive and nitrate robust areas with respectively low and high nitrate reduction potential. The research firstly...... nitrate reduction potential at grid scale is large. It should therefore be evaluated at which spatial scale the predicted nitrate reduction potential can be used. The reason for the lack of predictive capability at grid scale is insufficient description of spatial patterns of parameters and input data in...... the uncertainty on the estimated nitrate reduction potentials and evaluated on the predictive capability of catchment scale models. Among other results, the study found that geological uncertainty give rise to large uncertainty on the predicted nitrate reduction at grid scale, but the uncertainty...

  3. Development of a chronocoulometric method for uranium traces determination with basis on nitrate catalytic reduction

    International Nuclear Information System (INIS)

    The application of chronocoulometric technique with catalytic reduction of uranium/nitrate with catalytic reduction of uranium/nitrate system is described to give a detection limits on the sub-nanomolar region of uranium. (author)

  4. Role of Diatoms in the Spatial-Temporal Distribution of Intracellular Nitrate in Intertidal Sediment

    DEFF Research Database (Denmark)

    Stief, P.; Kamp, A.; de Beer, D.

    2013-01-01

    Intracellular nitrate storage allows microorganisms to survive fluctuating nutrient availability and anoxic conditions in aquatic ecosystems. Here we show that diatoms, ubiquitous and highly abundant microalgae, represent major cellular reservoirs of nitrate in an intertidal flat of the German...

  5. Development of a low cost, low environmental impact process for disposal of nitrate wastes

    International Nuclear Information System (INIS)

    A uranium recycle process in the Y-12 Plant generates nitrate ions which must be discarded. Scrap enriched uranium is dissolved in nitric acid and solvent extracted to remove impurities from the uranium. Aluminum nitrate is also used in the process to remove the purified uranium from the solvent extraction process. Dilute nitric acid, aluminum nitrate, and metallic impurities must be discarded from this process. A program was started to develop a low cost, low environmental impact process for disposal of these nitrate wastes. Several disposal methods were considered. A process was selected which included: distillation and recycle of nitric acid; crystallization and recycle of aluminum nitrate; and biodegradation of the remaining nitrate waste solutions. For this presentation, only the biodegradation process will be discussed. A colony of Pseudomonas stutzeri, which is capable of using the nitrate ion as the oxygen supply, was used. An excess of organic material was used to insure that the maximum amount of nitrate was destroyed

  6. Separation and recovery of sodium nitrate from low-level radioactive liquid waste by electrodialysis

    International Nuclear Information System (INIS)

    An advanced method, in which electrodialysis separation of sodium nitrate and decomposition of nitrate ion are combined, has been developed to remove nitrate ion from low-level radioactive liquid wastes including nitrate salts of high concentration. In the electrodialysis separation, the sodium nitrate was recovered as nitric acid and sodium hydroxide. When they are reused, it is necessary to reduce the quantity of impurities getting mixed with them from the waste fluid as much as possible. In this study, therefore, a cation exchange membrane with permselectivity for sodium ion and an anion exchange membrane with permselectivity for monovalent anion were employed. Using these membranes sodium and nitrate ions were effectively removed form a sodium nitrate solution of high concentration. And also it was confirmed that sodium ion was successfully separated from cesium and strontium ions and that nitrate ion was separated from sulfate and phosphate ions. (author)

  7. Initial kinetics of 15N-nitrate labelling of root and shoot N fractions of barley cultured at different relative addition rates of nitrate-N

    International Nuclear Information System (INIS)

    The reduction of absorbed nitrate in the root and N transport to the shoot were studied in young barley (Hordeum vulgare L.) plants growing at low external nitrate levels. Plants were grown at three relative addition rates (RA) of nitrate: 0.04, 0.09, and 0.14 d-1, which represent different degrees of growth limiting nitrate supply. Root nitrate reduction and N transport in situ were estimated using 15N labelled nitrate exposures ranging from 5 to 60 min. With increasing RA, nitrate uptake in absolute terms increased, but the proportion of absorbed 15N-nitrate that was reduced in the root decreased markedly. After 10-20 min of exposure to the label, 75, 49 and 27 % of the 15N taken up was recovered as reduced 15N in the root at RAs 0.04, 0.09, and 0.14 d-1, respectively. The response pattern was supported by root nitrate reductase activities and xylem sap nitrate measurements. The decreasing proportion of reduced 15N in the root with higher nitrate supply rates was matched by a relative increase in 15N-nitrate storage and, to some extent, an increase in N transport to the shoot. Although small amounts of 15N were rapidly transported to the shoot, the accumulation of label in the shoot at the end of the 60 min period remained a relatively small proportion of total 15N uptake, which indicates delayed movement of 15N out of the root. The results clearly indicate that differing degrees of adjustment occur in important nitrate assimilation processes throughout the N deficiency range. (author)

  8. Anaerobic Nitrate-Dependent Metal Bio-Oxidation

    Science.gov (United States)

    Weber, K.; Knox, T.; Achenbach, L. A.; Coates, J. D.

    2007-12-01

    Direct biological oxidation of reduced metals (Fe(II) and U(IV)) coupled to nitrate reduction at circumneutral pH under anaerobic conditions has been recognized in several environments as well as pure culture. Several phylogentically diverse mesophilic bacteria have been described as capable of anaerobic, nitrate-dependent Fe(II) oxidation (NFOx). Our recent identification of a freshwater mesophilic, lithoautotroph, Ferrutens nitratireducens strain 2002, capable of growth through NFOx presents an opportunity to further study metal bio- oxidation. Continuing physiological studies revealed that in addition to Fe(II) oxidation, strain 2002 is capable of oxidizing U(IV) (4 μM) in washed cell suspensions with nitrate serving as the electron acceptor. Pasteurized cultures exhibited abiotic oxidation of 2 μM U(IV). Under growth conditions, strain 2002 catalyzed the oxidation of 12 μM U(IV) within a two week period. Cultures amended with sodium azide, an electron transport inhibitor, demonstrated limited oxidation (7 μM) similar to pasteurized cultures, supporting the direct role of electron transport in U(IV) bio-oxidation. The oxidation of U(IV) coupled denitrification at circumneutral pH would yield enough energy to support anaerobic microbial growth (ΔG°'= -460.36 kJ/mole). It is currently unknown whether or not strain 2002 can couple this metabolism to growth. The growth of F. nitratireducens strain 2002 utilizing Fe(II) as the sole electron donor was previously demonstrated. The amount of U(IV) (~12 μM) that strain 2002 oxidized under similar autotrophic growth conditions yields 0.0019 kJ, enough energy for the generation of ATP (5.3 x 10-20 kJ ATP-1), but not enough energy for cell replication as calculated for nitrate-dependent Fe(II) oxidizing conditions (0.096 kJ) assuming a similar metabolism. In addition to F. nitratireducens strain 2002, a nitrate-dependent Fe(II) oxidizing bacterium isolated from U contaminated groundwater, Diaphorobacter sp. strain

  9. Nitrate in groundwater and the unsaturated zone, Shijiazhuang City, China

    International Nuclear Information System (INIS)

    In 2001, nitrate concentrations in water from wells in Shijiazhuang City, China ranged from 15 to about 160 mg/L as nitrate, with a median concentration of 50 mg/L. Agricultural return waters from lands irrigated with sewage or groundwater are believed to be the source of increasing nitrate, chloride, sulphate, and dissolved solids concentrations. Recharge rates estimated from chemical and tritium data are about 130 mm/y for non-irrigated agricultural land and exceed 200 mm/y for irrigated land. Nitrate concentrations in pore water in the unsaturated zone were as high as 930 mg/L. As much as 350 kg/ha of nitrogen is stored in the upper 18 m of the unsaturated zone beneath a groundwater irrigated site. As much as 780 kg/ha of nitrogen could be stored in thicker unsaturated zones within the study area and nitrogen storage beneath sewage irrigated sites is even probably greater. About 60% of the nitrate stored in the unsaturated zone is in the form of nitrate and 36% is in the form of ammonia. Denitrification in near-saturated fine-grained layers reduces the concentration of nitrate in with depth and at 18 m below land surface 60% of the nitrogen is in the form of ammonia. The δ15N composition of water from sampled wells ranged from 2.2 to 11.7 per mille, with median value of 6.1 per mille. Water from wells in the urban area had the highest average δ15N compositions with progressively lower values in the village and farmland areas. δ15N values in surficial soils averaged 1.0 per mille in natural sites, 9.5 per mille in sewage and manure amended sites, and 7.3 per mille in the chemically fertilized sites. Most δ15N values in water from wells are in the range of compositions expected from sewage and manure sources of nitrogen-with some denitrification, although extensive denitrification of nitrogen from chemical fertilizers also could produce observed δ15N values. (author)

  10. Influence of nitrate ions on the physicochemical behavior of neptunium

    International Nuclear Information System (INIS)

    The aim of this work was to acquire data on Np(VI) nitrate-complexes, particularly concerning their stability in nitric acid media, to gain a closer understanding of neptunium behavior in the PUREX process used for spent nuclear fuel reprocessing. Due to their very poor stability and the importance of physico-chemical mechanisms in concentrated solutions (media effects), the published data concerning these complexes are subject to considerable debate. A visible and near-infrared spectrophotometric study of Np(VI) nitrate-complexes was therefore undertaken to observe and quantify the influence of nitrate ions on the physicochemical behavior of neptunium, and to estimate the magnitude of the media effects in order to propose a constant of complexation by nitrate ions that is independent of the composition of the reaction medium (i.e. a thermodynamic constant). In the absence of reliable spectra for neptunium in nitric acid media, the spectrophotometric data were processed by principal components analysis and factor analysis mathematical method. The ionic strength of the solutions was adjusted by adding perchlorate salts (perchlorate ions were considered to have little or no complexing properties). The influence of the type of cation (H+, Li+, Na+, Ba2+, Mg2+) and the perchlorate ion concentration was observed on the neptunium(VI) spectra in nitric and perchloric media. In the presence of nitrate ions, the spectrum modifications in case of substitution of one cation by another were comparable to those observed for major nitrate ion concentration variations. Similarly, the extent of the spectrum modifications for the same nitrate ion concentration variation depended on the proton concentration. Weak spectrum modifications were also observed when the perchlorate ion concentration varied. They were quantified by a 'perturbation constant' β* calculated in the same way as a complexation constant (β* = 0.023 in the molal scale). To limit the disturbances responsible for

  11. Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards

    OpenAIRE

    Novara, A.; L. Gristina; F. Guaitoli; Santoro, A.; A. Cerdà

    2013-01-01

    When soil nitrate levels are low, plants suffer nitrogen (N) deficiency but when the levels are excessive, soil nitrates can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The research was carried out...

  12. The Nitrate Time Bomb (NTB) Model: a simple method with potential big impacts

    OpenAIRE

    Wang, Lei; Stuart, Marianne; Ward, Rob

    2015-01-01

    Nitrate water pollution, which remains an international problem, can cause long-term environmental damage and threaten both the economy and human health. Agricultural land is the major source of nitrate water pollution. Through recent research, it has become increasingly clear that it could take decades for nitrate leached from the soil to discharge into freshwaters. However, this nitrate time lag in the groundwater system has generally been ignored within the water resource management in the...

  13. Soil Nitrate Monitoring for Turfgrass Sod Farms and Other Turf Areas

    OpenAIRE

    W. Michael Sullivan; Zhongchun Jiang

    2001-01-01

    Studies with established turf and golf courses have indicated minimal risk of nitrate pollution of groundwater resulting from turfgrass management, but soil nitrate flux in turfgrass sod production farms and golf courses has received less attention. Information about nitrate-N flux at a particular location can be helpful to the sod producer or the golf course manager when efficiently applying N fertilizers and minimizing risk of nitrate pollution. We used an ion exchange resin capsule system ...

  14. Micro- and Mini-nitrate Sensors for Monitoring of Soils, Groundwater and Aquatic Systems

    OpenAIRE

    Ratâko, Alexander; Dietrich, Heidi; Park, Yeonjeong; Gonzalez-Jimenez, Ruby; Kim, Dohyun; Aswin, Buddy; Goldberg, Ira; Harmon, Thomas; Judy, Jack

    2009-01-01

    Inorganic nitrogen (nitrate, NO3-) is a major source of pollution in groundwater, surface water and the air. Application of nitrate-containing fertilizers can create distributed or non-point source pollution problems. Scalable nitrate sensors (sensors which are small and inexpensive) would enable us to better assess non-point source pollution processes in agronomic soils, groundwater and rivers. Sensor research groups in the CENS have been working toward high-performance scalable nitrate sen...

  15. Artificial electron donors for nitrate and nitrite reductases usable as mediators in amperometric biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Strehlitz, B. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Gruendig, B. (Institut fuer Chemo- und Biosensorik, Muenster-Roxel (Germany)); Vorlop, K.D. (Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (Germany). Inst. fuer Technologie); Bartholmes, P. (Witten-Herdecke Univ., Witten (Germany). Inst. fuer Biochemie); Kotte, H. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Stottmeister, U. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany))

    1994-07-01

    Various nitrate and nitrite reductases are capable of accepting electrons from artificial donors. Combining these redox active donors with an amperometric redox electrode which is covered with an immobilized layer of such a nitrate or nitrite reductase, new enzyme sensors can be created for the detection of nitrate or nitrite, respectively. A range of suitable electron donors for nitrate reductases and nitrite reductase from different sources have been selected and characterized by electrochemical methods. (orig.)

  16. Nitrate in the Mississippi River and Its Tributaries, 1980 to 2008: Are We Making Progress?

    OpenAIRE

    Sprague, Lori A.; Hirsch, Robert M.; Aulenbach, Brent T.

    2011-01-01

    Changes in nitrate concentration and flux between 1980 and 2008 at eight sites in the Mississippi River basin were determined using a new statistical method that accommodates evolving nitrate behavior over time and produces flow-normalized estimates of nitrate concentration and flux that are independent of random variations in streamflow. The results show that little consistent progress has been made in reducing riverine nitrate since 1980, and that flow-normalized concentration and flux are ...

  17. Nitrate groundwater pollution and aquifer vulnerability: the case of the Osona region

    OpenAIRE

    Boy Roura, Mercè

    2013-01-01

    Nitrate groundwater pollution in the Osona region is a persistent and widespread problem. Nitrate concentrations are commonly above the drinking water threshold of 50 mg/L in wells and springs. ANOVA and logistic regression analyses showed that nitrate concentration is more dependent on land use than on the geological setting of springs. Nitrate content presented stationary values in most of the springs over time, while discharge and electrical conductivity evolution depends on the geological...

  18. Nitrate absorption and strontium accumulation. Final report, 1 August 1973--31 December 1976

    International Nuclear Information System (INIS)

    Two basic objectives of this study to determine how strontium translocation, and discrimination between strontium and calcium in plants are influenced by nitrate uptake, assimilation, and translocation, and to characterize the relationships between nitrate uptake, nitrate assimilation, and nitrate translocation. Results are reported from studies using maize seedlings in which 85Sr and 45Ca were used as tracers. A list is included of publications that report the results of related studies

  19. Photocatalytic reduction of nitrate using titanium dioxide for regeneration of ion exchange brine

    OpenAIRE

    Yang, Ting; Doudrick, Kyle; Westerhoff, Paul

    2012-01-01

    Nitrate is often removed from groundwater by ion exchange (IX) before its use as drinking water. Accumulation of nitrate in IX brine reduces the efficiency of IX regeneration and the useful life of the regeneration brine. For the first time, we present a strategy to photocatalytically reduce nitrate in IX brine, thereby extending the use of the brine. Titanium dioxide (Evonik P90), acting as photocatalyst, reduced nitrate effectively in both synthetic brines and sulfate-removed IX brine when ...

  20. Soil nitrate reducing processes – drivers, mechanisms for spatial variation, and significance for nitrous oxide production

    OpenAIRE

    Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M; Daniell, Tim J.

    2012-01-01

    The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate ( NO 3 − ) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There...

  1. Soil nitrate reducing processes – drivers, mechanisms for spatial variation and significance for nitrous oxide production

    OpenAIRE

    TimJohnDaniell; MadelineEleanoreGiles

    2012-01-01

    The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3-¬) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH and the size and community structure of nitrate reducing organisms responsible for the processes. Ther...

  2. Study on the nitrite and nitrate levels changes by drying and frying processing in vegetables

    OpenAIRE

    Sadeghi, E; K Sharafi; A Almasi; M Dayhim; E Azizi; M Ghayebzadeh

    2014-01-01

    Background and objectives: Nitrate and nitrite threaten the human health. According to recent research works, one of the great sources of exposure to nitrate and nitrite in human diet is vegetables. The aim of this study is to determine the effect of drying and frying processes on nitrate and nitrite levels in abundant vegetables. Materials and methods: In this descriptive – analytical study, 180 vegetable samples were taken randomly from Kermanshah markets. Nitrite and nitrate concentrati...

  3. Spectrophotometric study of neptunium (VI) complexation by nitrate ions

    International Nuclear Information System (INIS)

    Neptunium(VI) complexation by nitrate ions was investigated by visible and near-infrared spectrophotometry, a technique suitable for observing the appearance and evolution of the species in solution. In the absence of reference spectra for Np(VI) nitrate- complexes, mathematical (factor analysis) tools were used to interpret the spectra. These chemo-metric techniques were first tested and validated on a simpler chemical system: Np(VI)complexation by the SiW11O398- anion. The test media used to investigate Np(VI) nitrate- complexes generally contain nitrate and perchlorate salts at high concentrations (high ionic strength). Media effects arising from the presence of cations, acidity or the perchlorate ion concentration are therefore significant, and no doubt account for the scattered values of the complexation constants published in the literature. The evolution of the neptunium spectra according to the parameters of the reaction medium illustrated these effects and allowed them to be quantified by a global 'perturbation constant'. In order to minimize the spectrum modifications due to media effects, the neptunium nitrate-complexes were studied at constant ionic strength in weak acidic media (2 mol.kg-1H2O) in the presence of sodium salts. The bulk formation constants and the spectrum of the NpO2(NO3)+ complex were determined for ionic strength values of 2.2, 4, 6 and 8 mol.kg-1H2O. The constants remained on the same order of magnitude regardless of the ionic strength; the thermodynamic constant β10 determined from them according to specific interaction theory is thus probably of little significance. Conversely, the bulk constants can be corrected for the effects of the perchlorate ions by taking the global 'perturbation constant' into account. (author)

  4. Experimental evaluation of cement materials for solidifying sodium nitrate

    International Nuclear Information System (INIS)

    Low-level liquid waste containing sodium nitrate is planned to be transformed to salt block by evaporation with sodium borate in the Low-level Waste Treatment Facility (LWTF), then salt block will be stored temporally. It should be important to investigate the method how to treat these liquid waste suitable to final disposal criteria that will be settled in future. Cement solidification is one of promising candidates because it has been achieved as the solidification material for the shallow land disposal. The research was conducted to evaluate applicability of various cement materials to solidification of sodium nitrate. The following cements were tested. Ordinary Portland Cement (OPC). Portland Blast-furnace Slag Cement; C type (PBFSC). Alkali Activated Slag Cement (AASC, supplied by JGC). The test results are as follows; (1) AASC is characterized by a high sodium nitrate loading (-70 wt%) compared with other types of cement material. High fluidity of the cement paste, high strength after solidification, and minimization of free water on the cement paste are achieved under all test conditions. (2) OOPC and PBFSC produced free water on the cement paste in the early days and delayed the hardening period. 3 or more days are required to harden evan with 30 wt% content of sodium nitrate. (3) Though PBFSC contains blast furnace slag similar to AASC, there is no advantage prior to OPC. To design an ideal cement conditioning system for sodium nitrate liquid waste in the LWTF, the further studies are necessary such as the simulated waste test, Kd test, pilot test, and layout design. (author)

  5. Scaleable Nitrate Microsensors in the Form of a Plant Root

    Science.gov (United States)

    Harmon, T. C.; Jurisch, N. L.; Davidson, M. J.; Haux, J. E.

    2004-12-01

    This work describes the development of flexible, miniature and inexpensive nitrate sensors by electropolymerizing pyrrole onto carbon fiber substrates, using nitrate as a dopant. Carbon microfibers were found to be an excellent substitute to expensive conductive materials, such as glassy carbon or platinum. The electrodes with a 3-5 micron layer of NO3 -doped polypyrrole (PPy) exhibited a promising lifetime (at least 2 month without changes in sensitivity and linear response), fast response times (seconds), and sensitivity competitive to commercial nitrate ISE. Nernstian sensor response slopes of 54 to 58 mV/(decade concentration) for single filament have been observed, with a linear response to nitrate concentrations spanning three orders of magnitude (0.1 - 10-4 M or 6200 - 6.2 ppm of NO3-), and a detection limit of (3 ± 1) x 10-5 M (1.25-2.5 ppm). An advantage of using the carbon fibers as a substrate for pyrrole polymerization process is that these fibers are relatively easy to manipulate, lending themselves to root-like electrode designs which may be ideal for observing the water chemistry of soil moisture. Using prototypical PPy-coated microfibers, we have been able to directly measure nitrate concentrations in residual soil water contents as low as 8 percent by weight for a medium sand. Results for model soils and field samples are presented in which direct measurements with the microsensors compare reasonably well with a more conventional analytical method entailing soil extraction and analysis by the Griess-Romijn method.

  6. Nitrate Enhanced Microbial Cr(VI) Reduction-Final Report

    Energy Technology Data Exchange (ETDEWEB)

    John F. Stolz

    2011-06-15

    A major challenge for the bioremediation of radionuclides (i.e., uranium, technetium) and metals (i.e., Cr(VI), Hg) is the co-occurrence of nitrate as it can inhibit metal transformation. Denitrification (nitrate reduction to dinitrogen gas) is considered the most important ecological process. For many metal and metalloid reducing bacteria, however, ammonia is the end product through respiratory nitrate reduction (RNRA). The focus of this work was to determine how RNRA impacts Cr(VI) transformation. The goal was to elucidate the specific mechanism(s) that limits Cr(VI) reduction in the presence of nitrate and to use this information to develop strategies that enhance Cr(VI) reduction (and thus detoxification). Our central hypothesis is that nitrate impacts the biotransformation of metals and metalloids in three ways 1) as a competitive alternative electron acceptor (inhibiting transformation), 2) as a co-metabolite (i.e., concomitant reduction, stimulating transformation), and 3) as an inducer of specific proteins and pathways involved in oxidation/reduction reactions (stimulating transformation). We have identified three model organisms, Geobacter metallireducens (mechanism 1), Sulfurospirillum barnesii, (mechasism 2), and Desulfovibrio desulfuricans (mechanisms 3). Our specific aims were to 1) investigate the role of Cr(VI) concentration on the kinetics of both growth and reduction of nitrate, nitrite, and Cr(VI) in these three organisms; 2) develop a profile of bacterial enzymes involved in nitrate transformation (e.g., oxidoreductases) using a proteomic approach; 3) investigate the function of periplasmic nitrite reductase (Nrf) as a chromate reductase; and 4) develop a strategy to maximize microbial chromium reduction in the presence of nitrate. We found that growth on nitrate by G. metallireducens was inhibited by Cr(VI). Over 240 proteins were identified by LC/MS-MS. Redox active proteins, outer membrane heavy metal efflux proteins, and chemotaxis sensory

  7. Effect of high electron donor supply on dissimilatory nitrate reduction pathways in a bioreactor for nitrate removal

    DEFF Research Database (Denmark)

    Behrendt, Anna; Tarre, Sheldon; Beliavski, Michael;

    2014-01-01

    The possible shift of a bioreactor for NO3- removal from predominantly denitrification (DEN) to dissimilatory nitrate reduction to ammonium (DNRA) by elevated electron donor supply was investigated. By increasing the C/NO3- ratio in one of two initially identical reactors, the production of high ...

  8. Thermal characterization of nitrates and nitrates/expanded graphite mixture phase change materials for solar energy storage

    International Nuclear Information System (INIS)

    Highlights: • The addition of expanded graphite improved apparent thermal conductivity significantly. • The quadratic parallel model was used to predict the effective thermal conductivity. • The melting/freezing temperatures of mixture PCMs shifted slightly with adding of EG. - Abstract: Solar energy storage has become more attractive in recent years. In particular, latent thermal energy storage (LTES) with large energy storage density and isothermal heat storage/retrieval characteristics is a hot research topic. In the present study, sodium nitrate, potassium nitrate and their mixture were used as the base materials, and expanded graphite (EG) with high thermal conductivity and thermo-chemical stability was used as an additive to enhance the thermal conductivity. EG with various mass fractions was added to the base materials to form mixture phase change materials (PCMs), and the thermal characteristics of the mixtures were studied extensively. The transient hot-wire tests showed that the addition of EG enhanced the apparent thermal conductivity significantly, e.g. the apparent thermal conductivity of the nitrates/10 wt.% EG mixture PCM was increased by about 30–40%. The test results showed good agreement with theoretical calculations of the quadratic parallel model. Tests with differential scanning calorimeter (DSC) revealed that the melting/freezing temperatures of the mixture PCMs shifted slightly, compared with those of pure nitrates

  9. Conversion of neodymium oxide with N2O4 into nitrate followed by supercritical fluid extraction of nitrate

    International Nuclear Information System (INIS)

    A novel method that spent nuclear fuel is converted into nitrates with N2O4, and then nitrates are extracted with TBP in supercritical CO2 (SC-CO2), has been developed for reprocessing of spent nuclear fuel, which has a potential prospect because of its potential to decrease generation of the secondary liquid waste. In this paper, conversion of Nd2O3 with N2O4 into its nitrate under various conditions and extraction of the conversion product with TBP in SC-CO2 were investigated. When temperature was 60-120 deg C, the molar ratio of H2O to Nd2O3 was from 1 to 6, and molar ratio of N2O4 to Nd2O3 was above 8, complete conversion of Nd2O3 into its nitrate was achieved. The conversion product was characterized by thermal analysis (TG-DTA), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR) and Raman spectroscopy. Quantitative extraction of the conversion product with TBP in supercritical CO2 was also achieved under experimental conditions. (author)

  10. Identification and quantification of a novel nitrate-reducing community in sediments of Suquia River basin along a nitrate gradient

    International Nuclear Information System (INIS)

    We evaluated the molecular diversity of narG gene from Suquia River sediments to assess the impact of the nitrate concentration and water quality on the composition and structure of the nitrate-reducing bacterial community. To this aim, a library of one of the six monitoring stations corresponding to the highest nitrate concentration was constructed and 118 narG clones were screened. Nucleotide sequences were associated to narG gene from alpha-, beta-, delta-, gammaproteobacteria and Thermus thermophilus. Remarkably, 18% of clones contained narG genes with less than 69% similarity to narG sequences available in databases. Thus, indicating the presence of nitrate-reducing bacteria with novel narG genes, which were quantified by real-time PCR. Results show a variable number of narG copies, ranging from less than 1.0 x 102 to 5.0 x 104 copies per ng of DNA, which were associated with a decreased water quality index monitored along the basin at different times. - A novel narG community present in Suquia River sediments was quantified; values were in line with the water quality index.

  11. Prevention of nitrate formation in aqueous primary coolant circuits of nuclear power plants

    International Nuclear Information System (INIS)

    As nitrogen source for radiation-induced nitrate formation in air-saturated water of primary coolant circuits dissolved ammonia was identified. Since nitrate is supposed to cause corrosion its formation should be prevented. The addition of a small amount of ethanol prevents the nitrate formation for a long period as calculated from kinetic data obtained by pulse radiolysis. (author)

  12. Leaching of nitrate from agriculture to groundwater: the effect of policies and measures in the Netherlands

    NARCIS (Netherlands)

    Oenema, O.; Boers, P.C.M.; Eerdt, van M.M.; Fraters, B.; Meer, van der H.G.; Roest, C.W.J.; Schröder, J.J.; Willems, W.J.

    1998-01-01

    Nitrate concentrations in groundwater are correlated with the nitrogen surpluses at the soil surface. In the Netherlands, both nitrogen surpluses of agricultural land and nitrate concentrations in the groundwater of sandy soils are high. At present, nitrate concentrations in the groundwater of sandy

  13. Small-scale, hydrogen-oxidizing-denitrifying bioreactor for treatment of nitrate-contaminated drinking water

    Science.gov (United States)

    Nitrate removal by hydrogen-coupled denitrification was examined using flow-through, packed-bed bioreactors to develop a small-scale, cost effective system for treating nitrate-contaminated drinking-water supplies. Nitrate removal was accomplished using a Rhodocyclus sp., strain HOD 5, isolated fro...

  14. Indirect control of the intracellular nitrate pool of intertidal sediment by the polychaete Hediste diversicolor

    DEFF Research Database (Denmark)

    Heisterkamp, Ines Maria; Kamp, Anja; Schramm, Angela T.; de Beer, Dirk; Stief, Peter

    2012-01-01

    In an intertidal flat of the German Wadden Sea, a large sedimentary pool of intracel- lular nitrate was discovered that by far exceeded the pool of nitrate that was freely dissolved in the porewater. Intracellular nitrate was even present deep in anoxic sediment layers where it might be used for ...

  15. 75 FR 29534 - Inorganic Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft...

    Science.gov (United States)

    2010-05-26

    ... AGENCY Inorganic Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft... draft ecological risk assessment for the registration review of inorganic nitrates - nitrites, carbon... occur for all inorganic nitrates- nitrites, carbon and carbon dioxide uses, as well as gas...

  16. [Nitrate and nitrite in prepared meals in relation to the nitrate concentration of drinking water (author's transl)].

    Science.gov (United States)

    Selenka, F; Brand, E

    1975-12-01

    The nitrate and nitrite content of prepared foods was investigated in four areas in Rhineland Palatinate. The nitrate content of the drinking water was different in each area, the first region always having less than 1 mg NO-3/litre, the second an average of 19.5 mg NO-3/litre, the third an average of 35.6 mg NO-3/litre and the fourth 130 mg NO-3/litre. The samples were restaurant food which had been served without previously informing the maker. They were separately analysed according to soup, meat and gravy, carbohydrate accompaniments, vegetables and salad. It was shown that, in the four areas (in the above order) an average of 46, 67, 45 and 65 mg NO-3/main meal was ingested, which corresponds to a ratio of 1:1.5:1:1.4. For nitrites, the figures were 1.4, 2.0, 1.5, and 2.8 mg NO-2/main meal, corresponding to a ratio of 1:1.4:1.1:2. The nitrate excess consumed by the population in the principal meals in areas with a drinking water concentration of 130 mg/1 is consequently only 1.4 times higher than in an area where the water supply is free from nitrate. Under the same conditions the nitrite content is doubled. However, the levels at 2 and 1 mg NO-2/kg are altogether very low and are not likely to be of any importance hygienically for the public at large. The concentrations of nitrate in potatoes and carbohydrate accompaniments (94 mg NO-3/kg), vegetables (99 mg NO-3/kg) and salads (109 mg NO-3/kg) show average levels which are double those of soups (50 mg NO-3/kg) and meat dishes (58 mg NO-3kg). An effect of the nitrate content of drinking water on these figures is only seen in soups and meat, an increase by a factor of 4 occurring between the area with nitrate-gree drinking water and the area with 130 mg NO-3/1). Contrary to expectation, the nitrite levels show the reverse relationship. They are highest in soups (4.7 mg NO-2/kg) and meat dishes (3.5 mg NO-2/kg) to salads (1.4 mg NO-3/kg). The values obtained may be considered representative for the average

  17. Distant electric coupling between nitrate reduction and sulphide oxidation investigated by an improved nitrate microscale biosensor

    Science.gov (United States)

    Marzocchi, U.; Revsbech, N. P.; Nielsen, L. P.; Risgaard-Petersen, N.

    2012-04-01

    Bacteria are apparently able to transmit electrons to other bacteria (Summers et al. 2010) or to electrodes (Malvankar et al. 2011) by some kind of nanowires (Reguera et al. 2005, Gorbi et al. 2006). Lately it has been shown that such transfer may occur over distances of centimetres in sediments, thereby coupling sulphide oxidation in deeper layers with oxygen reduction near the surface (Nielsen 2011). The finding of these long-distance electrical connections originated from analysis of O2, H2S, and pH profiles measured with microsensors. Nitrate is thermodynamically almost as good an electron acceptor as O2, and we therefore set up an experiment to investigate whether long-distance electron transfer also happens with NO3-. Aquaria were filled with sulphidic marine sediment from Aarhus Bay that was previously used to show long-distance electron transfer to O2. The aquaria were equipped with a lid so that they could be completely filled without a gas phase. Anoxic seawater with 300 μM NO3- was supplied at a constant rate resulting in a steady state concentration in the aquatic phase of 250 μM NO3-. The reservoir with the nitrate-containing water was kept anoxic by bubbling it with a N2/CO2 mixture and was kept at an elevated temperature. The water was cooled on the way to the aquaria to keep the water in the aquaria undersaturated with gasses, so that bubble formation by denitrification in the sediment could be minimised. Profiles of NO3-, H2S, and pH were measured as a function of time (2 months) applying commercial sensors for H2S and pH and an improved microscale NO3- biosensor developed in our laboratory. The penetration of NO3- in the sediment was 4-5 mm after 2 months, whereas sulphide only could be detected below 8-9 mm depth. The electron acceptor and electron donor were thus separated by 4-5 mm, indicating long distance electron transfer. A pH maximum of about 8.6 pH units at the NO3- reduction zone similar to a pH maximum observed in the O2 reduction

  18. Organic Nitrates and Nitrate Resistance in Diabetes: The Role of Vascular Dysfunction and Oxidative Stress with Emphasis on Antioxidant Properties of Pentaerithrityl Tetranitrate

    Directory of Open Access Journals (Sweden)

    Matthias Oelze

    2010-01-01

    Full Text Available Organic nitrates represent a class of drugs which are clinically used for treatment of ischemic symptoms of angina as well as for congestive heart failure based on the idea to overcome the impaired NO bioavailability by “NO” replacement therapy. The present paper is focused on parallels between diabetes mellitus and nitrate tolerance, and aims to discuss the mechanisms underlying nitrate resistance in the setting of diabetes. Since oxidative stress was identified as an important factor in the development of tolerance to organic nitrates, but also represents a hallmark of diabetic complications, this may represent a common principle for both disorders where therapeutic intervention should start. This paper examines the evidence supporting the hypothesis that pentaerithrityl tetranitrate may represent a nitrate for treatment of ischemia in diabetic patients. This evidence is based on the considerations of parallels between diabetes mellitus and nitrate tolerance as well as on preliminary data from experimental diabetes studies.

  19. Comparative induction of nitrate reductase by nitrate and nitrite in barley leaves

    Science.gov (United States)

    Aslam, M.; Rosichan, J. L.; Huffaker, R. C.

    1987-01-01

    The comparative induction of nitrate reductase (NR) by ambient NO3- and NO2- as a function of influx, reduction (as NR was induced) and accumulation in detached leaves of 8-day-old barley (Hordeum vulgare L.) seedlings was determined. The dynamic interaction of NO3- influx, reduction and accumulation on NR induction was shown. The activity of NR, as it was induced, influenced its further induction by affecting the internal concentration of NO3-. As the ambient concentration of NO3- increased, the relative influences imposed by influx and reduction on NO3- accumulation changed with influx becoming a more predominant regulant. Significant levels of NO3- accumulated in NO2(-)-fed leaves. When the leaves were supplied cycloheximide or tungstate along with NO2-, about 60% more NO3- accumulated in the leaves than in the absence of the inhibitors. In NO3(-)-supplied leaves NR induction was observed at an ambient concentration of as low as 0.02 mM. No NR induction occurred in leaves supplied with NO2- until the ambient NO2- concentration was 0.5 mM. In fact, NR induction from NO2- solutions was not seen until NO3- was detected in the leaves. The amount of NO3- accumulating in NO2(-)-fed leaves induced similar levels of NR as did equivalent amounts of NO3- accumulating from NO3(-)-fed leaves. In all cases the internal concentration of NO3-, but not NO2-, was highly correlated with the amount of NR induced. The evidence indicated that NO3- was a more likely inducer of NR than was NO2-.

  20. Nitrate Contamination of Deep Aquifers in the Salinas Valley, California

    Science.gov (United States)

    Moran, J. E.; Esser, B. K.; Hillegonds, D. J.; Holtz, M.; Roberts, S. K.; Singleton, M. J.; Visser, A.; Kulongoski, J. T.; Belitz, K.

    2011-12-01

    The Salinas Valley, known as 'the salad bowl of the world', has been an agricultural center for more than 100 years. Irrigated row crops such as lettuce and strawberries dominate both land use and water use. Groundwater is the exclusive supply for both irrigation and drinking water. Some irrigation wells and most public water supply wells in the Salinas Valley are constructed to draw water from deep portions of the aquifer system, where contamination by nitrate is less likely than in the shallow portions of the aquifer system. However, a number of wells with top perforations greater than 75 m deep, screened below confining or semi-confining units, have nitrate concentrations greater than the Maximum Contaminant Limit (MCL) of 45 mg/L as NO3-. This study uses nitrate concentrations from several hundred irrigation, drinking water, and monitoring wells (Monterey County Water Resources Agency, 1997), along with tritium-helium groundwater ages acquired at Lawrence Livermore National Laboratory through the State of California Groundwater Monitoring and Assessment (GAMA) program (reported in Kulongoski et al., 2007 and in Moran et al., in press), to identify nitrate 'hot spots' in the deep aquifer and to examine possible modes of nitrate transport to the deep aquifer. In addition, observed apparent groundwater ages are compared with the results of transport simulations that use particle tracking and a stochastic-geostatistical framework to incorporate aquifer heterogeneity to determine the distribution of travel times from the water table to each well (Fogg et al., 1999). The combined evidence from nitrate, tritium, tritiogenic 3He, and radiogenic 4He concentrations, reveals complex recharge and flow to the capture zone of the deep drinking water wells. Widespread groundwater pumping for irrigation accelerates vertical groundwater flow such that high nitrate groundwater reaches some deep drinking water wells. Deeper portions of the wells often draw in water that recharged

  1. Quantifying atmospheric nitrate formation pathways based on a global model of the oxygen isotopic composition (Δ17O of atmospheric nitrate

    Directory of Open Access Journals (Sweden)

    J. A. Thornton

    2009-05-01

    Full Text Available The oxygen isotopic composition (Δ17O of atmospheric nitrate is a function of the relative abundance of atmospheric oxidants (O3, HOx=OH +HO2+RO2 and the formation pathway of nitrate from its precursor NOx (=NO+NO2. Coupled observations and modeling of nitrate Δ17O can be used to quantify the relative importance of chemical formation pathways leading to nitrate formation and reduce uncertainties in the budget of reactive nitrogen chemistry in the atmosphere. We present the first global model of atmospheric nitrate Δ17O and compare with available observations. The model shows the best agreement with a global compilation of observations when assuming a Δ17O value of tropospheric ozone equal to 35‰ and preferential oxidation of NOx by the terminal oxygen atoms of ozone. Calculated values of annual-mean nitrate Δ17O in the lowest model layer (0–200 m above the surface vary from 6‰ in the tropics to 41‰ in the polar-regions. On the global scale, O3 is the dominant oxidant (81% annual-mean during NOx cycling reactions. The global, annual-mean tropospheric inorganic nitrate burden is dominated by nitrate formation via NO2+OH (76%, followed by N2O5 hydrolysis (18% and NO3+DMS/HC (4%. Model discrepancies are largest in the polar spring and summer, most likely due to the lack of reactive halogen chemistry in the model. The influence of organic nitrates on observations of nitrate Δ17O needs to be determined, especially for observations in summertime and tropical forested regions where organic nitrates can contribute up to 80% of the total NOy (organic plus inorganic nitrate budget.

  2. Nitrate and nitrite-mediated transcription antitermination control of nasF (nitrate assimilation) operon expression in Klebsiella pheumoniae M5al.

    Science.gov (United States)

    Lin, J T; Stewart, V

    1996-03-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources during aerobic growth. Nitrate is converted through nitrite to ammonium by assimilatory nitrate and nitrite reductase, respectively. Enzymes required for nitrate assimilation are encoded by the nasFEDCBA operon of K. pneumoniae; nasF operon expression is subject to both general nitrogen control and pathway-specific nitrate/nitrite induction, mediated by the NtrC and NasR proteins, respectively. Sequence inspection revealed a presumptive sigmaN (sigma54)-dependent promoter as well as two presumptive upstream NtrC protein binding sites. Site-specific mutational and primer extension analyses confirmed the identity of the sigmaN-dependent promoter. Deletions removing the apparent NtrC protein binding sites greatly reduced NtrC-dependent regulation, indicating that these sites are involved in general nitrogen control. However, deletions removing most of the sequence upstream of the promoter had little effect on nitrate/nitrite regulation, suggesting that the nasF leader region is involved in nitrate/nitrite regulation. The 119 nucleotide long transcribed leader region contains an apparent factor-independent transcription terminator. Promoter replacement experiments demonstrated that the leader region is involved in nitrate/nitrite regulation of nasF operon expression. Deletions removing the transcription terminator structure resulted in a nitrate-blind constitutive phenotype, indicating that the transcription terminator structure serves a negative function. Other deletions, removing proximal portions of the leader region, resulted in an uninducible phenotype, indicating that this region serves a positive function. These results indicate that nitrate/nitrite regulation of nasF operon expression is determined by a transcription attenuation mechanism. We hypothesize that in the absence of nitrate or nitrite, the terminator structure abrogates transcription readthrough into the nasF operon. In the

  3. Evaluation of Endocrine Disrupting Effects of Nitrate after In Utero Exposure in Rats and of Nitrate and Nitrite in the H295R and T-Screen Assay

    DEFF Research Database (Denmark)

    Hansen, Pernille Reimer; Taxvig, Camilla; Christiansen, Sofie; Petersen, Marta Axelstad; Boberg, Julie; Kiersgaard, Maria Kristina; Nellemann, Christine Lydia; Hass, Ulla

    2009-01-01

    of effects of nitrate on male sexual development, the aim of the study was to examine how in utero exposure to nitrate would affect male rat fetuses. Pregnant dams were dosed with nitrate in the drinking water from gestational day (GD) 7 to GD21 at the following dose levels 17.5, 50, 150, 450, and...... 900 mg/l. At GD21, fetuses were examined for anogenital distance, plasma thyroxine levels, testicular and plasma levels of testosterone and progesterone, and testicular testosterone production and histopathology. In addition, endocrine disrupting activity of nitrate and nitrite were studied in two in...

  4. Effect of nitrate on activity and community structure of a sulfidogenic wastewater biofilm

    DEFF Research Database (Denmark)

    Kofoed, Michael Vedel Wegener; Mohanakrishnan, Janani; Schramm, Andreas;

    reactor for 10 days. Gradients of nitrate and sulfide were recorded with microsensors before and after the addition of nitrate, and changes in community composition and biofilm activity were monitored on DNA and RNA level by denaturing gradient gel electrophoresis of 16S rRNA, sulfite reductase(dsrB), and......-like SRB to Desulfomicrobium-like species. Fluoresence in situ hybridization of SRB confirmed the shift and furthermore demonstrated that SRB, after nitrate addition, were overgrown by other, presumably nitrate reducing bacteria. Genes and transcripts of the periplasmic nitrate reductase could only be...

  5. Observations of total peroxy nitrates and total alkyl nitrates during the OP3 campaign: isoprene nitrate chemistry above a south-east Asian tropical rain forest

    Directory of Open Access Journals (Sweden)

    E. Aruffo

    2012-02-01

    Full Text Available Measurements of total peroxy nitrates (ΣRO2NO2, ΣPNs, total alkyl nitrates (ΣRONO2, ΣANs and nitrogen dioxide (NO2 were made above the surface of a Malaysian tropical rain forest in Borneo, using a laser-induced fluorescence instrument developed at the University of L'Aquila (Italy. This new instrument uses the direct excitation of NO2 at 532 nm in order to measure its concentrations detecting by the NO2 fluorescence at wavelengths longer than 610 nm. ΣPNs and ΣANs are indirectly measured after their thermal dissociation into NO2. Observations showed enhanced levels of NO2 during nighttime, an increase of ΣPNs during the afternoon and almost no evident diurnal cycle of ΣANs. The diurnal maximums of 200 pptv for ΣPNs and ΣANs are well below the peaks reported in other forest sites. A box model constrained with measured species, reproduces well the observed ΣPNs, but overestimates ΣANs concentrations. The reason of this model-observation discrepancy could be a wrong parameterization in the isoprene nitrates (INs chemistry mechanism. Sensitivity tests show that: (1 reducing the yield of INs from the reaction of peroxy nitrates with NO to almost the lowest values reported in literature (5%, (2 reducing the INs recycling to 70% and (3 keeping the INs dry deposition at 4 cm s−1, improve the agreement between modelled and measured ΣANs of 20% on average. These results imply that in the tropical rain forest, even if ΣPNs and ΣANs concentrations are lower than those observed in other North American forests, the yield and dry deposition of INs are similar. Another comparable result is that in the INs oxidation its recycling dominates with only a 30% release of NO2, which has implications on tropospheric ozone production and aerosol budget.

  6. Dietary nitrate improves cardiac contractility via enhanced cellular Ca(2+) signaling.

    Science.gov (United States)

    Pironti, Gianluigi; Ivarsson, Niklas; Yang, Jiangning; Farinotti, Alex Bersellini; Jonsson, William; Zhang, Shi-Jin; Bas, Duygu; Svensson, Camilla I; Westerblad, Håkan; Weitzberg, Eddie; Lundberg, Jon O; Pernow, John; Lanner, Johanna; Andersson, Daniel C

    2016-05-01

    The inorganic anion nitrate (NO3 (-)), which is naturally enriched in certain vegetables (e.g., spinach and beetroot), has emerged as a dietary component that can regulate diverse bodily functions, including blood pressure, mitochondrial efficiency, and skeletal muscle force. It is not known if dietary nitrate improves cardiac contractility. To test this, mice were supplemented for 1-2 weeks with sodium nitrate in the drinking water at a dose similar to a green diet. The hearts from nitrate-treated mice showed increased left ventricular pressure and peak rate of pressure development as measured with the Langendorff heart technique. Cardiomyocytes from hearts of nitrate-treated and control animals were incubated with the fluorescent indicator Fluo-3 to measure cytoplasmic free [Ca(2+)] and fractional shortening. Cardiomyocytes from nitrate-treated mice displayed increased fractional shortening, which was linked to larger Ca(2+) transients. Moreover, nitrate hearts displayed increased protein expression of the L-type Ca(2+) channel/dihydropyridine receptor and peak L-type Ca(2+) channel currents. The nitrate-treated hearts displayed increased concentration of cAMP but unchanged levels of cGMP compared with controls. These findings provide the first evidence that dietary nitrate can affect the expression of important Ca(2+) handling proteins in the heart, resulting in increased cardiomyocyte Ca(2+) signaling and improved left ventricular contractile function. Our observation shows that dietary nitrate impacts cardiac function and adds understanding to inorganic nitrate as a physiological modulator. PMID:27071401

  7. Contrasting nitrate adsorption in Andisols of two coffee plantations in Costa Rica.

    Science.gov (United States)

    Ryan, M C; Graham, G R; Rudolph, D L

    2001-01-01

    Fertilizer use in coffee plantations is a suspected cause of rising ground water nitrate concentrations in the ground water-dependent Central Valley of Costa Rica. Nitrate adsorption was evaluated beneath two coffee (Coffea arabica L.) plantations in the Central Valley. Previous work at one site had identified unsaturated zone nitrate retardation relative to a tritium tracer. Differences in nitrate adsorption were assessed in cores to 4 m depth in Andisols at this and one other plantation using differences in KCl- and water-extractable nitrate as an index. Significant adsorption was confirmed at the site of the previous tracer test, but not at the second site. Anion exchange capacity, X-ray diffraction data, extractable Al and Si, and soil pH in NaF corroborated that differences in adsorption characteristics were related to subtle differences in clay mineralogy. Soils at the site with significant nitrate adsorption showed an Al-rich allophane clay content compared with a more weathered, Si-rich allophane and halloysite clay mineral content at the site with negligible adsorption. At the site with significant nitrate adsorption, nitrate occupied less than 10% of the total anion adsorption capacity, suggesting that adsorption may provide long-term potential for mitigation or delay of nitrate leaching. Evaluation of nitrate sorption potential of soil at local and landscape scales would be useful in development of nitrogen management practices to reduce nitrate leaching to ground water. PMID:11577895

  8. Nuclear microprobe imaging of gallium nitrate in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Richard E-mail: ortega@cenbg.in2p3.fr; Suda, Asami; Deves, Guillaume

    2003-09-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 {mu}m diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material.

  9. Hormones and nitrate: a two-way connection.

    Science.gov (United States)

    Krouk, Gabriel

    2016-08-01

    During their sessile mode of life, plants need to endure variations in their environment such as a drastic variability in the nutrient concentration in soil solution. It is almost trivial to say that such fluctuations in the soil modify plant growth, development and phase transitions. However, the signaling pathways underlying the connections between nitrogen related signaling and hormonal signaling controlling growth are still poorly documented. This review is meant to present how nitrate/nitrogen controls hormonal pathways. Furthermore, it is very interesting to highlight the increasing evidence that the hormonal signaling pathways themselves seem to feed back control of the nitrate/nitrogen transport and assimilation to adapt nutrition to growth. This thus defines a feed-forward cycle that finely coordinates plant growth and nutrition. PMID:27003907

  10. Design and evaluation of liposomal formulation of pilocarpine nitrate

    Directory of Open Access Journals (Sweden)

    Rathod S

    2010-01-01

    Full Text Available Prolonged release drug delivery system of pilocarpine nitrate was made by optimizing thin layer film hydration method. Egg phosphatidylcholine and cholesterol were used to make multilamellar vesicles. Effects of charges over the vesicles were studied by incorporating dicetylphosphate and stearylamine. Various factors, which may affect the size, shape, encapsulation efficiency and release rate, were studied. Liposomes in the size range 0.2 to 1 ΅m were obtained by optimizing the process. Encapsulation efficiency of neutral, positive and negatively charged liposomes were found to be 32.5, 35.4 and 34.2 percent, respectively. In vitro drug release rate was studied on specially designed model. Biological response in terms of reduction in intraocular pressure was observed on rabbit eyes. Pilocarpine nitrate liposomes were lyophilized and stability studies were conducted.

  11. Engineering Options Assessment Report. Nitrate Salt Waste Stream Processing

    International Nuclear Information System (INIS)

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 above-ground UNS, and 79 candidate below-ground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  12. Isopiestic density law of actinide nitrates applied to criticality calculations

    International Nuclear Information System (INIS)

    Up to now, criticality safety experts used density laws fitted on experimental data and applied them in and outside the measurement range. Depending on the case, such an approach could be wrong for nitrate solutions. Seven components are concerned: UO2(NO3)2, U(NO3)4, Pu(NO3)4, Pu(NO3)3, Th(NO3)4, Am(NO3)3 and HNO3. To get rid of this problem, a new methodology based on the thermodynamic concept of binary electrolytes solutions mixtures at constant water activity, so called 'isopiestic' solutions, has been developed by IRSN to calculate the nitrate solutions density. This article shortly presents the theoretical aspects of the method, its qualification using benchmarks and its implementation in IRSN graphical user interface. (author)

  13. Influence of macrophytes on nitrate removal in wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Weisner, S.E.B.; Eriksson, Peder G.; Graneli, W.; Leonardson, L. (Lund Univ. (Sweden). Dept. of Ecology)

    1994-01-01

    Efficient nitrate removal from wetlands depends on denitrification. Macrophytes support denitrification by supplying organic carbon. Organic carbon available to denitrifying bacteria is released from plant litter and from living macrophytes. Macrophytes offer attachment surfaces for epiphytes, also producing organic matter, and for denitrifying bacteria. Emergent macrophytes are generally more productive than submerged macrophytes, but submerged macrophytes have more epiphytes and offer a larger attachment area in the water column for denitrifying bacteria. Emergent and submerged vegetation differ in their seasonal patterns of release of organic carbon. We conclude that a mixture of emergent and submerged macrophytes may be beneficial for nitrogen removal in wetlands with a surface-flow of nitrate-rich water. The influence of vegetation on wetland hydraulics must also be considered. A wetland design with deeper parts favoring submerged macrophytes alternating, along the water flow, with shallower parts covered by emergent macrophytes, may promote denitrification processes and distribution of water flow. 41 refs, 5 figs

  14. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

    International Nuclear Information System (INIS)

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S0), N2, and CO2, or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 1000 mg/L influent sulfide, however, the DSR system will break down.

  15. Evaluation of uranyl nitrate crystallization for spent nuclear fuel separations

    International Nuclear Information System (INIS)

    Previous work in Germany and Japan has indicated that crystallization of uranyl nitrate at low temperatures from nitric acid solution could be a useful process for removing most of the uranium from spent LWR fuel after the fuel is dissolved in nitric acid. The crystallization process potentially could reduce the cost of LWR fuel partitioning because it provides a selective and compact process for removing most of the uranium which is about 96% of the LWR spent fuel mass. Subsequent separation processes would only need to handle the smaller volume of remaining actinides and the fission products. We are evaluating an approach to separating uranyl nitrate that uses a continuous adiabatic reduced-pressure crystallizer to concentrate and cool a nitric acid solution from dissolution of spent fuel. Initial work to define the process flowsheet and obtain data on optimum crystallization conditions and the purity of the uranium product will be presented. (authors)

  16. Engineering Options Assessment Report. Nitrate Salt Waste Stream Processing

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-13

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 above-ground UNS, and 79 candidate below-ground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  17. Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-18

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 aboveground UNS, and 79 candidate belowground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  18. Heterogeneous-catalytic redox reactions in nitrate - formate systems

    International Nuclear Information System (INIS)

    It was found that an intensive destruction of various organic and mineral substances - usual components of aqueous waste solutions (oxalic acid, complexones, urea, hydrazine, ammonium nitrate, etc.) takes place under the conditions of catalytic denitration. Kinetics and mechanisms of urea and ammonium nitrate decomposition in the system HNO3 - HCOOH - Pt/SiO2 are comprehensively investigated. The behaviour of uranium, neptunium and plutonium under the conditions of catalytic denitration is studied. It is shown, that under the certain conditions the formic acid is an effective reducer of the uranium (VI), neptunium (VI, V) and plutonium (VI, IV) ions. Kinetics of heterogeneous-catalytic red-ox reactions of uranium (VI), neptunium (VI, V) and plutonium (VI, IV) with formic acid are investigated. The mechanisms of the appropriate reactions are evaluated. (authors)

  19. Nuclear microprobe imaging of gallium nitrate in cancer cells

    Science.gov (United States)

    Ortega, Richard; Suda, Asami; Devès, Guillaume

    2003-09-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 μm diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material.

  20. FORMULATION AND EVALUATION OF TRANSDERMAL PATCH OF SERTACONAZOLE NITRATE

    Directory of Open Access Journals (Sweden)

    Kansagra Hemang

    2012-11-01

    Full Text Available The present work was designed to develop suitable transdermal matrix patch of sertaconazole nitrate, which is of the imidazole class used for antifungal medication, using Ethyl cellulose (EC, Polyvinyl pyrrolidone (PVPK-30 and Dibutyl phthalate. The aqueous insolubility of the drug inspires for the formulation of controlled release transdermal patches. Different batches developed using Ethyl cellulose and Polyvinyl pyrrolidone in different ratios by solvent evaporation technique. Drug excipient interaction study was further carried out using Fourier Transform Infrared (FTIR spectroscopic technique. Physical evaluation performed such as moisture content, moisture uptake, thickness and folding endurance. In vitro diffusion studies were performed using cellulose nitrate membrane (pore size 0.45μ in modified Franz’s diffusion cells in buffer of pH 7.4. Permeation studies illustrated that the ratio of polyvinyl pyrrolidone and ethyl cellulose 1:5 shows good controlled release. Higuchi and Korsmeyer-Peppas models were used for optimizing the formulation.

  1. Production of gadolinium nitrate for TAPS 3 and 4 PHWR

    International Nuclear Information System (INIS)

    In India, gadolinium nitrate is being used for the first time in PHWR at Tarapur. Gadolinium is preferred over boron due to high neutron cross section and the water soluble nitrate form works efficiently for reactivity control through moderator liquid poison addition system (MLPS) as well as for reactor shut down system (SDS2). Low concentration of gadolinium (0.1-0.2 g/l) in heavy water is sufficient to shut down the reactor in a very short time. After use, the small amount of gadolinium can be separated quickly from heavy water by ion exchange process. In this paper separation of Gd using of 2-ethyl hexyl phosphoric acid mono 2-ethyl hexyl ester EHEHPA as an extractant has been described

  2. Characteristics of nitrate horizontal transport in a paddy field of the Tai Lake region, China.

    Science.gov (United States)

    Chen, X M; Shen, Q R; Pan, G X; Liu, Z P

    2003-02-01

    The characteristics of nitrate horizontal transport in a major paddy soil, Wu Shan soil in the Tai Lake region, were studied. The concentration of nitrate during horizontal movement decreased with the increasing in distance from the tracer source, the change following a logarithmic function. The concentration of the nitrate was strongly correlated with the soil moisture content, as an exponential function. The horizontal transport velocity of nitrate was significantly correlated with the distance of the tracer source as power function. Therefore, the velocity of nitrate horizontal transport was controlled by the concentration gradient of nitrate, and soil water potential gradient from beginning to the 20 cm mark in the horizontal column. However, the velocity of nitrate horizontal was stable beyond 20 cm, where it was controlled by soil matric potential. PMID:12688479

  3. CHEMICAL DENITRIFICATION OF NITRATE FROM GROUNDWATER VIA SULFAMIC ACID AND ZINC METAL

    Directory of Open Access Journals (Sweden)

    A. Sabzali, M. Gholami, A. R. Yazdanbakhsh, A. Khodadadi, B. Musavi, R. Mirzaee

    2006-07-01

    Full Text Available Nitrate contamination in drinking water can cause methemoglobinemia, which is especially detrimental to infants and nursing mothers. Batch experiments in two units for catalytic reduction of nitrate from groundwater with Zn catalyst and sulfamic acid were conducted. The system includes chemical denitriphication (ChemDen reactor and electrolytic recovery reactoers. A batch study was conducted to optimize parameters like pH, sulfamic acid concentration, Zn concentration, temperature and reaction time governing the ChemDen process. The concentrations of remained nitrate and Zn were measured at the end of the reactions. Results showed that near to 100% of nitrate decreased and the quantity of remained nitrate was <1 mg/L. pH and agitation had great effect on denitrification, and the nitrate removal rate changed rapidly when pH value ranged between 3-4. Two water quality parameters which limit this process were sulfate and chloride ions concentrations in nitrate contaminated water.

  4. Alkyl nitrate distributions and seasonal variation over the Pacific Ocean during HIPPO

    Science.gov (United States)

    Atlas, E. L.; Smith, K.; Zhu, X.; Pope, L.; Lueb, R.; Hendershot, R.; Moore, F. L.; Miller, B. R.; Montzka, S. A.; Elkins, J. W.; Wofsy, S. C.

    2012-12-01

    Alkyl nitrates are produced in both the atmosphere and in the ocean by photochemical oxidation of organic precursors. Past studies have shown that low molecular weight alkyl nitrates, particularly methyl and ethyl nitrate, have high production rates and air-sea fluxes from equatorial ocean waters. In addition, high concentrations of these organic nitrates have been found in the atmosphere of the Southern Ocean. Measurements during the HIPPO campaign were able to characterize the tropospheric distribution of these alkyl nitrates over all seasons, and from virtually pole to pole over the Central Pacific Ocean. The measurements from HIPPO confirm the strong equatorial source and in addition show a strong asymmetry in methyl nitrate concentrations between hemispheres, with the Southern Hemisphere having consistently higher concentrations compared to the Northern Hemisphere. This presentation will discuss the alkyl nitrate distributions, sources, and variations observed during the HIPPO campaign and examine relationships to other trace gases of oceanic origin, such as DMS and methyl iodide.

  5. Investigation of processes leading to nitrate enrichment in soils in the Kalahari Region, Botswana

    Science.gov (United States)

    Schwiede, M.; Duijnisveld, W. H. M.; Böttcher, J.

    In Southern Africa elevated nitrate concentrations are observed in mostly uninhabited semi-arid areas. In the Kalahari of Botswana groundwater locally exhibits concentrations up to 600 mg/l. It is assumed, that nitrate found in the groundwater originates mainly from nitrogen input and transformations in the soils. Our investigations in the Kalahari between Serowe and Orapa show that cattle raising is an important source for enhanced nitrate concentrations in the soils (Arenosols). But also in termite mounds very high nitrate stocks were found, and under natural vegetation (acacia trees and shrubs) nitrate concentrations were mostly unexpectedly high. This nitrate enrichment in the soils poses a serious threat to the groundwater quality. However, calculated soil water age distributions in the unsaturated zone clearly show that today’s nitrate pollution of the groundwater below the investigation area could originate from natural sources, but cannot be caused by the current land use for cattle raising.

  6. Nitrate pollution of groundwater by pit latrines in developing countries

    OpenAIRE

    Templeton, Michael R.; Acile S. Hammoud; Adrian P. Butler; Laura Braun; Julie-Anne Foucher; Johanna Grossmann; Moussa Boukari; Serigne Faye; Jean Patrice Jourda

    2015-01-01

    Pit latrines are one of the most common forms of onsite sanitation facilities in many developing countries. These latrines are suitable as a means of isolating human waste, however, conditions within pits often lead to nitrification of the contained waste. In areas with a near-surface aquifer, the potential for nitrate pollution arising from pit latrines cannot be ignored. In this study, site visits were made to three densely populated, peri-urban areas near three West African cities (Dakar, ...

  7. ACUTE TOXICITY OF LEAD NITRATE ON FRESHWATER CRAB BARYTELPHUSA GUERINI

    OpenAIRE

    DUBE, KAUSHAL V

    2012-01-01

    Industrial effluents contributing to aquatic pollution contain vast array of toxic substances including heavy metals.  Indiscriminate discharge of these wastes alters the quality of water and cause hazards to aquatic fauna including important members of food chain of man. Hence, in present investigation the freshwater crab, Barytelphusa guerini was exposed to acute toxicity of lead nitrate for 0, 24, 48, 72 and 96 hours exposure. The percentage mortality of crab was studied and the LC50 deter...

  8. Nitrate pollution risk assessment : from the model to the indicator

    OpenAIRE

    Lacroix, Anne; Laurent, François; Ruelland, Denis; Sauboua, Emmanuelle

    2006-01-01

    The diffuse nature of nitrate pollution makes it difficult to evaluate existing or planned measures to reduce it. Tools are therefore been developed to assess this pollution, ranging from simple indicators to complex models. The aim of this paper is to compare indicators and models by analysing results obtained from their individual application to the same area. The pros and cons of each approach are evaluated in terms of both the conditions of their implementation and the results obtained. T...

  9. Nitrative Stress Participates in Endothelial Progenitor Cell Injury in Hyperhomocysteinemia

    Science.gov (United States)

    Dong, Yu; Sun, Qi; Liu, Teng; Wang, Huanyuan; Jiao, Kun; Xu, Jiahui; Liu, Xin; Liu, Huirong; Wang, Wen

    2016-01-01

    In order to investigate the role of nitrative stress in vascular endothelial injury in hyperhomocysteinemia (HHcy), thirty healthy adult female Wistar rats were randomly divided into three groups: control, hyperhomocysteinemia model, and hyperhomocysteinemia with FeTMPyP (peroxynitrite scavenger) treatment. The endothelium-dependent dilatation of thoracic aorta in vitro was determined by response to acetylcholine (ACh). The histological changes in endothelium were assessed by HE staining and scanning electron microscopy (SEM). The expression of 3-nitrotyrosine (NT) in thoracic aorta was demonstrated by immunohistochemistry and immunofluorescence, and the number of circulating endothelial progenitor cells (EPCs) was quantified by flow cytometry. Hyperhomocysteinemia caused significant endothelial injury and dysfunction including vasodilative and histologic changes, associated with higher expression of NT in thoracic aorta. FeTMPyP treatment reversed these injuries significantly. Further, the effect of nitrative stress on cultured EPCs in vitro was investigated by administering peroxynitrite donor (3-morpholino-sydnonimine, SIN-1) and peroxynitrite scavenger (FeTMPyP). The roles of nitrative stress on cell viability, necrosis and apoptosis were evaluated with 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium (MTT) assay, lactate dehydrogenase (LDH) release assay and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, respectively. Also, the phospho-eNOS expression and tube formation in Matrigel of cultured EPCs was detected. Our data showed that the survival of EPCs was much lower in SIN-1 group than in vehicle group, both the apoptosis and necrosis of EPCs were much more severe, and the p-eNOS expression and tube formation in Matrigel were obviously declined. Subsequent pretreatment with FeTMPyP reversed these changes. Further, pretreatment with FeTMPyP reversed homocysteine-induced EPC injury. In conclusion, this study indicates that

  10. Blood pressure, sodium intake, insulin resistance, and urinary nitrate excretion.

    Science.gov (United States)

    Facchini, F S; DoNascimento, C; Reaven, G M; Yip, J W; Ni, X P; Humphreys, M H

    1999-04-01

    The objective of this study was to investigate the relationships among various humoral factors thought to be involved in the regulation of blood pressure during high NaCl intake. Nineteen healthy subjects underwent sequential 5-day periods ingesting a low-sodium (25 mmol/d) or high-sodium (200 mmol/d) diet. Insulin resistance was assessed by the steady-state plasma glucose concentration at the end of a 3-hour insulin suppression test. Insulin resistance correlated inversely with natriuresis (P=0.04) and directly with increase in weight (P=0.03). The increase in mean arterial pressure associated with the high-sodium diet correlated directly with the gain in weight (P<0.05) and inversely with the increase in urinary nitrate excretion (P<0.0001). In a multiple regression model, more than 2/3 of the variance in mean arterial pressure was accounted for by the gain in weight and change in urinary nitrate excretion. The steady-state plasma glucose concentrations obtained with the 2 diets were similar, indicating that insulin resistance was unaffected by sodium intake. During high sodium intake, plasma renin activity and aldosterone decreased and plasma atrial natriuretic peptide increased; these changes did not correlate with the change in mean arterial pressure, insulin resistance, or change in urinary nitrate excretion. To the extent that urinary nitrate excretion reflects activity of the endogenous nitric oxide system, these results suggest that the salt sensitivity of mean arterial pressure may be related to blunted generation of endogenous nitric oxide. The results also demonstrate that insulin-resistant individuals have an impaired natriuretic response to high sodium intake. PMID:10205239

  11. Inflammation induces fibrinogen nitration in experimental human endotoxemia

    OpenAIRE

    Heffron, Sean P.; Parastatidis, Ioannis; Cuchel, Marina; Wolfe, Megan L; Tadesse, Mahlet G.; Mohler, Emille R.; Ischiropoulos, Harry; Rader, Daniel J.; Reilly, Muredach P.

    2009-01-01

    Elevated plasma fibrinogen is a prothrombotic risk factor for cardiovascular disease (CVD). Recent small studies report that fibrinogen oxidative modifications, specifically tyrosine residue nitration, can occur in inflammatory states and may modify fibrinogen function. HDL cholesterol is inversely related to CVD and suggested to reduce the oxidation of LDL cholesterol, but whether these antioxidant functions extend to fibrinogen modifications is unknown. We used a recently validated ELISA to...

  12. The Mechanism of Nitrate Pollution in Soil and Groundwater

    Institute of Scientific and Technical Information of China (English)

    王志敏; 诸葛敏; 杨玉峥

    2013-01-01

    Soil and groundwater which are important natural resources are closely related with human health.It will be hard to recover,if it is polluted.Nitrate has become one of the most serious harmful substances contaminated in soil and groundwater.A large number of studies have shown that high fertilizer and irrigation was the main reason of soil and groundwater pollution.Pollution is mainly concentrated in agricultural developed area.

  13. Nitrite and Nitrate Removal Efficiencies of Soil Aquifer Treatment Columns

    OpenAIRE

    GÜNGÖR, Kerem; ÜNLÜ, Kahraman

    2005-01-01

    Bench-scale soil column experiments were performed to examine the effects of soil type and infiltration conditions on the removal efficiencies of wastewater nitrites and nitrates during the biological ripening phase of soil aquifer treatment (SAT) columns. SAT was simulated in three 1-m-high soil columns packed with 3 different natural agricultural soils having sandy clay loam (SCL), loamy sand (LS) and sandy loam (SL) textures. All columns were equipped with tensiometers and soil-wa...

  14. Transport of nitrated albumin across continuous vascular endothelium

    OpenAIRE

    Predescu, Dan; Predescu, Sanda; Malik, Asrar B.

    2002-01-01

    Because modification of plasma albumin on tyrosine residues generates nitrated albumin (NOA) that may function as a mechanism of nitrogen monoxide clearance from microcirculation, we investigated biochemicaly and morphologically the cell surface binding and the transendothelial transport of NOA. An electron microscopic study was carried out with mouse lungs and hearts perfused in situ with NOA and NOA-Au complexes. The results indicate that NOA-Au can bind to the endothelial cell surface, and...

  15. Nitrate contamination risk assessment in groundwater at regional scale

    Science.gov (United States)

    Daniela, Ducci

    2016-04-01

    Nitrate groundwater contamination is widespread in the world, due to the intensive use of fertilizers, to the leaking from the sewage network and to the presence of old septic systems. This research presents a methodology for groundwater contamination risk assessment using thematic maps derived mainly from the land-use map and from statistical data available at the national institutes of statistic (especially demographic and environmental data). The potential nitrate contamination is considered as deriving from three sources: agricultural, urban and periurban. The first one is related to the use of fertilizers. For this reason the land-use map is re-classified on the basis of the crop requirements in terms of fertilizers. The urban source is the possibility of leaks from the sewage network and, consequently, is linked to the anthropogenic pressure, expressed by the population density, weighted on the basis of the mapped urbanized areas of the municipality. The periurban sources include the un-sewered areas, especially present in the periurban context, where illegal sewage connections coexist with on-site sewage disposal (cesspools, septic tanks and pit latrines). The potential nitrate contamination map is produced by overlaying the agricultural, urban and periurban maps. The map combination process is very easy, being an algebraic combination: the output values are the arithmetic average of the input values. The groundwater vulnerability to contamination can be assessed using parametric methods, like DRASTIC or easier, like AVI (that involves a limited numbers of parameters). In most of cases, previous documents produced at regional level can be used. The pollution risk map is obtained by combining the thematic maps of the potential nitrate contamination map and the groundwater contamination vulnerability map. The criterion for the linkages of the different GIS layers is very easy, corresponding to an algebraic combination. The methodology has been successfully

  16. Mitochondrial efficiency : focus on dietary nitrate, hypoxia and exercise

    OpenAIRE

    Schiffer, Tomas

    2014-01-01

    Metabolic efficiency affects weight control, generation of heat, exercise performance and health. The tiny radical nitric oxide (NO) targets several cellular components that can influence metabolic efficiency. NO is produced endogenously from L-arginine and molecular oxygen by specific NO-synthases. In addition, extensive research during the past two decades shows that the inorganic anions nitrate and nitrite, which are oxidation products from endogenous NO generation, can be redu...

  17. crnA encodes a nitrate transporter in Aspergillus nidulans

    OpenAIRE

    Unkles, S.E.; Hawker, K L; Grieve, C; Campbell, E I; Montague, P.; Kinghorn, J R

    1995-01-01

    The nucleotide sequence of the Aspergillus nidulans crnA gene for the transport of the anion nitrate has been determined. The crnA gene specifies a predicted polypeptide of 483 amino acids (molecular weight 51,769). A hydropathy plot suggests that this polypeptide has 10 membrane-spanning helices with an extensive hydrophilic region between helices six and seven. No striking homology was observed between the crnA protein and other reported membrane proteins of either prokaryotic or eukaryotic...

  18. Enhanced surface photochemistry in chloride-nitrate ion mixtures

    Czech Academy of Sciences Publication Activity Database

    Wingen, L. M.; Moskun, A. C.; Johnson, S. N.; Thomas, J. L.; Roeselová, Martina; Tobias, D. J.; Kleinman, M. T.; Finlayson-Pitts, B. J.

    2008-01-01

    Roč. 10, č. 37 (2008), s. 5668-5677. ISSN 1463-9076 R&D Projects: GA MŠk LC512; GA MŠk 1P05ME798 Grant ostatní: NSF(US) CHE0431512 Institutional research plan: CEZ:AV0Z40550506 Keywords : aqueous sodium nitrate * air-water interface * molecular dynamics simulation * atmospheric aerosols Subject RIV: CC - Organic Chemistry Impact factor: 4.064, year: 2008

  19. Nitrative Stress Participates in Endothelial Progenitor Cell Injury in Hyperhomocysteinemia.

    Science.gov (United States)

    Dong, Yu; Sun, Qi; Liu, Teng; Wang, Huanyuan; Jiao, Kun; Xu, Jiahui; Liu, Xin; Liu, Huirong; Wang, Wen

    2016-01-01

    In order to investigate the role of nitrative stress in vascular endothelial injury in hyperhomocysteinemia (HHcy), thirty healthy adult female Wistar rats were randomly divided into three groups: control, hyperhomocysteinemia model, and hyperhomocysteinemia with FeTMPyP (peroxynitrite scavenger) treatment. The endothelium-dependent dilatation of thoracic aorta in vitro was determined by response to acetylcholine (ACh). The histological changes in endothelium were assessed by HE staining and scanning electron microscopy (SEM). The expression of 3-nitrotyrosine (NT) in thoracic aorta was demonstrated by immunohistochemistry and immunofluorescence, and the number of circulating endothelial progenitor cells (EPCs) was quantified by flow cytometry. Hyperhomocysteinemia caused significant endothelial injury and dysfunction including vasodilative and histologic changes, associated with higher expression of NT in thoracic aorta. FeTMPyP treatment reversed these injuries significantly. Further, the effect of nitrative stress on cultured EPCs in vitro was investigated by administering peroxynitrite donor (3-morpholino-sydnonimine, SIN-1) and peroxynitrite scavenger (FeTMPyP). The roles of nitrative stress on cell viability, necrosis and apoptosis were evaluated with 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium (MTT) assay, lactate dehydrogenase (LDH) release assay and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, respectively. Also, the phospho-eNOS expression and tube formation in Matrigel of cultured EPCs was detected. Our data showed that the survival of EPCs was much lower in SIN-1 group than in vehicle group, both the apoptosis and necrosis of EPCs were much more severe, and the p-eNOS expression and tube formation in Matrigel were obviously declined. Subsequent pretreatment with FeTMPyP reversed these changes. Further, pretreatment with FeTMPyP reversed homocysteine-induced EPC injury. In conclusion, this study indicates that

  20. Electrochemical Destruction of Nitrates and Organics FY1995 Progress Report

    International Nuclear Information System (INIS)

    Production of nuclear materials within the DOE complex has yielded large volumes of high-level waste containing hazardous species such as nitrate, nitrite, chromium, and mercury. Processes being developed for the permanent disposal of these wastes are aimed at separating the bulk of the radioactivity, primarily 137-Cs and 90-Sr, into a small volume for incorporation into a vitrified wasteform, with the remainder being incorporated into a low-level wasteform

  1. Observation of nitrate coatings on atmospheric mineral dust particles

    Directory of Open Access Journals (Sweden)

    W. J. Li

    2008-11-01

    Full Text Available Nitrate compounds have recently received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of nitrate-coated mineral particles in an individual particle scale in field study. The sample collection was conducted during brown haze and dust episodes occurred between 24 May and 21 June 2007 in Beijing, northern China. The sizes, morphologies, and compositions of mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM. 92% of the internally mixed mineral particles analyzed are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The major coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with less sulfates and chlorides. These nitrate coatings strongly relate with the presence of alkaline mineral components (e.g., calcite and dolomite within individual mineral particles. Calcium sulfate particles with the diameter from 10 to 500 nm were also detected within Ca(NO32 and Mg(NO32 coatings. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3. Mineral particles that acquire hygroscopic coatings tend to be more spherical and larger. Such changes enhance their light scattering and CCN activity, both of which have cooling effects on the climate.

  2. Nitrates in drinking water: relation with intensive livestock production

    OpenAIRE

    GIAMMARINO, M.; Quatto, P

    2015-01-01

    Summary Introduction. An excess of nitrates causes environmental pollution in receiving water bodies and health risk for human, if contaminated water is source of drinking water. The directive 91/676/ CEE [1] aims to reduce the nitrogen pressure in Europe from agriculture sources and identifies the livestock population as one of the predominant sources of surplus of nutrients that could be released in water and air. Directive is concerned about cattle, sheep, pigs and poultry and their territ...

  3. Nitrate contamination of groundwater as a factor of atmospheric pollution

    International Nuclear Information System (INIS)

    High nitrate concentrations of ground water in agricultural regions not only enhance denitrification in gravel pit lakes but also increase the proportion of nitrous oxide (N2O) in the gaseous products released to the atmosphere. Thereby they contribute to the greenhouse effect and destruction of the stratospheric ozone layer. However, due to the present small area of the lakes, their effect may be considered as important at the global scale

  4. Grain legumes and nitrate leaching: significance and prevention

    OpenAIRE

    Jensen, E.S.; Hauggaard-Nielsen, H; Aveline, A. (collab.); Crozat, Y.

    2004-01-01

    The amount of internationally published evidence on the effects of grain legumes on nitrate leaching is sparse and some studies may have weak points. Nevertheless, this mini-review indicates that the level of N leaching is 0–20 kg N ha-1 greater after pea than after cereals. Methods to prevent N leaching should be further developed and there is a need to genetically improve the root systems of grain legumes.

  5. Transition Metal Carbohydrazide Nitrates: Burn-rate Modifiers for Propellants

    Directory of Open Access Journals (Sweden)

    S. H. Sonawane

    2006-07-01

    Full Text Available This paper discusses the synthesis and characterisation of cobalt (Co, nickel (Ni andcopper (Cu carbohydrazide nitrates. In differential scanning calorimetry (DSC, the complexesexhibited exothermic decomposition indicating their energetic nature. The commencement ofdecomposition was observed at 220 °C for Ni complex, and at 160 °C for Co complex whereasthat of Cu complex occurred at 75 °C. In view of the better thermal stability, Ni and Co complexeswere selected for further study. The activation energy of decomposition of Ni and Co complexeswere found to be 47 kcal/mol and 60 kcal/mol respectively. Impact and friction sensitivity testresults revealed relatively lower vulnerability of carbohydrazide cobalt nitrate. Its incorporationin an ammonium perchlorate (AP-based composite propellant led to 9-19 per cent enhancementwhereas that of carbohydrazide nickel nitrate resulted in 28-74 per cent enhancement in burningrates in the pressure range 1.9 MPa to 8.8 MPa. Exothermic decomposition of the coordinationcomplexes on propellant surface and involvement of metal at molecular level formed ondecomposition of the complexes in combustion environment of composite propellant may beattributed to the catalytic effect of this class of compounds on the lines of reported literature.

  6. Corrosion performance of several metals in plutonium nitrate solution

    International Nuclear Information System (INIS)

    Corrosion behavior of several metals exposed in plutonium nitrate solution was studied. Plutonium nitrate solution with the plutonium concentration ranging from 0.01 to 300 g/l was used as a corrosive medium. Specimens tested were type 304 ULC (304 ULC) stainless steel, type 310 Nb (310 Nb) stainless steel, titanium (Ti), titanium-5% tantalum alloy (Ti-5Ta), and zirconium (Zr). Corrosion behavior of these metals in plutonium nitrate solution was evaluated through examining electrochemical characteristics and corrosion rates obtained by weight loss measurement. From the results of the corrosion tests, it was found that the corrosion rate of stainless steels i.e. 304 ULC and 310 Nb, increases by the presence of plutonium in nitric acid solution. The corrosion potential of the stainless steels shifted linearly towards the noble direction as the concentration of plutonium increases. It is thought that the shifts in corrosion potential of the stainless steels to the noble direction results an increase in anodic current and, hence, corrosion rate. Valve metals, i.e. Ti, Ti-5Ta and Zr, showed good corrosion resistance over the whole range of plutonium concentration examined here. (author)

  7. Waste generation reduction - nitrates. Comprehensive report of denitrification technologies

    International Nuclear Information System (INIS)

    A five-year denitrification technology development program has been conducted at the Rocky Flats Plant and has identified several promising denitrification methods. DOE sites were first surveyed to determine nitrate waste generation rates, inventory and regulatory concerns. The need for processes to handle this waste category was evident, both from the survey results and comments of site operations. The denitrification methods identified are classified as thermal, aqueous and biological; physical disposal is also discussed. Thermal processes were demonstrated to destroy the nitrates with the creation of less than 500 ppM NO/sub x/ as a by-product. Studies were performed on a molten salt destructor, a high temperature fluid wall reactor (HTFWR), a glass furnace, a plasma arc furnace, laser excitation and microwave heating. A preliminary design and cost estimate report was prepared for a one million kilogram-per-year process for denitrification using the HTFWR. Monsanto Research Corporation-Mound published a report of their glass furnace denitrification efforts. An aqueous process consisting of formic acid and sulfuric acid reflux was developed which converts the nitrate to other forms, but results in slightly elevated NO/sub x/ emissions. Biodenitrification was developed at Oak Ridge National Laboratory and is in production use at Oak Ridge Y-12 Plant. Results and conclusions on the program are discussed. 17 refs., 10 figs., 26 tabs

  8. Electrodialysis of Pu-contaminated ammonium nitrate solution

    International Nuclear Information System (INIS)

    Ammonium nitrate is the major component of Pu-contaminated liquid waste generated at the Pu-fuel facilities, and its safe decomposition was experimented by the method of electrodialysis. The process consists of two steps. The one is the electrodialysis of ammonium nitrate to ammonium nitrite in aqueous solution, and the other is the thermal decomposition of the ammonium nitrite to water and nitrogen gas also in aqueous solution. A thermal decomposition column and a heat exchanger were used for the continuous decomposition experiments. The membrane was a cation exchange membrane, the anolyte was 0.1 - 0.5 mol nitric acid, the catholyte was 10 - 50 weight % ammonium nitrate, and the current density was 10 - 50 amp/dm2. The experimental results of the pH and temperature effects on the current efficiency show that electrodialysis is preferable in alkaline region and at lower temperature. It is important to control such minor reactions as ammonium hydroxide byproduction as little as possible. The minor reaction of nitrogen gas generation greatly reduces the current efficiency of ammonium nitrite production. The best current efficiency achieved in the experiments was 85% by selecting the best operating conditions. In order to achieve high current efficiency in electrodialysis, the selection of electrolyzer composition, anode, cation exchange membrane, etc. is indispensable. It is generally preferable to choose the metal which has high hydrogen overvoltage to achieve high current efficiency by controlling hydrogen gas generation. (Wakatsuki, Y.)

  9. Groundwater pollution by nitrates in irrigated areas with drainage

    International Nuclear Information System (INIS)

    Field studies were conducted at three selected sites in irrigated areas of Pakistan to assess magnitude and severity of groundwater pollution by nitrates. The results of these studies indicate that concentration of nitrates in most of the samples collected from irrigated areas having drainage facility is much lower than threshold limit. The nitrate-nitrogen level within drainage projects ranges from 0.01-9.00 mg/l and in the area without drainage system ranges from 10.1-12.5 mg/l. The mineral fertilizers though are making contribution of NO3-N to the groundwater sources but that is much lower than threshold limits. The presence of septic tanks or farmyard manure dumps is also significant contributors of NO3-N to the groundwater. Thus drinking water sources near these polluting points are probable danger to human health. It is, therefore, concluded that still there is a lot of potential for fertilizer use in the agriculture but proper drainage facilities should be provided to minimize the potential threat of NO/sub 3/ pollution. (author)

  10. Ammonium and potassium effect on nitrate assimilation in cucumber seedlings

    Directory of Open Access Journals (Sweden)

    J. Buczek

    2015-05-01

    Full Text Available The effect of ammonium present in the induction medium toghether with nitrate on the activity of nitrate reductase (NR, nitrite reductase (NiR, glutamic acid dehydrogenase (GDH and absorption and accumulation of NO3- in cucumber seedlings were investigated. Maximum NR and NiR activity in the cotyledons was observed when seedlings were supplied with KNO3 as the sole source of nitrogen. When plants were supplied with NH4NO3 the presence of NH4+ in the induction medium repressed by about 50 per cent the activity of both reductases in the cotyledons. Addition of K+ to this medium abolished completely the inhibitory effect of NH4+. The effect of K+ cannot be replaced by that Na+ ions. On the other hand, ammonium has no effect on the level of NR activity in roots, while NiR was almost completely repressed. Under the experimental conditions ammonium, in the presence of nitrates, decreased the activity of GDH, but this diminution did not occur when the plants were supplied with K+ simultaneously. It has found that NH4+ ions reduced NO3- absorption but at the same time, the ratio of NO3- absorbed to that reduced was increased more than twice. The presumable mechanism of these phenomena is discussed.

  11. Studies on catalytic reduction of nitrate in groundwater

    Institute of Scientific and Technical Information of China (English)

    GENG Bing; ZHU Yanfang; JIN Zhaohui; LI Tielong; KANG Haiyan; WANG Shuaima

    2007-01-01

    Catalytic reduction of nitrate in groundwater by sodium formate over the catalyst was investigated.Pd-Cu/γ-Al2O3 catalyst was prepared by impregnation and characterized by brunauer-emmett-teller (BET),inductive coupled plasma (ICP),X-ray diffraction (XRD),transmission electron microscopy (TEM) and energy dispersive X-ray (EDX).It was found that total nitrogen was effectively removed from the nitrate solution (100 mg/L) and the removal efficiency was 87%.The catalytic activity was affected by pH,catalyst amount used,concentration of sodium formate,and initial concentration of nitrate.As sodium formate was used as reductant,precise control in the initial pH was needed.Excessively high or low initial pH (7.0 or 3.0) reduced catalytic activity.At initial pH of 4.5,catalytic activity was enhanced by reducing the amount of catalyst,while concentrations of sodium formate increased with a considerable decrease in N2 selectivity.In which case,catalytic reduction followed the first order kinetics.

  12. Precipitation of nitrate-cancrinite in Hanford Tank Sludge.

    Science.gov (United States)

    Buck, E C; McNamara, B K

    2004-08-15

    The chemistry of underground storage tanks containing high-level waste at the Hanford Site in Washington State is an area of continued research interest. Thermodynamic models have predicted the formation of analcime and clinoptilolite in Hanford tanks, rather than cancrinite; however, these predictions were based on carbonate-cancrinite. We report the first observation of a nitrate-cancrinite [possibly Na8(K,Cs)(AlSiO4)6(NO3)2 x nH2O] extracted from a Hanford tank 241-AP-101 sample that was evaporated to 6, 8, and 10 M NaOH concentrations. The nitrate-cancrinite phase formed spherical aggregates (4 microm in diameter) that consisted of platy hexagonal crystals (approximately 0.2 microm thick). Cesium-137 was concentrated in these aluminosilicate structures. These phases possessed a morphology identical to that of nitrate-cancrinite synthesized using simulant tests of nonradioactive tank waste, supporting the contention that it is possible to develop nonradioactive artificial sludges. This investigation points to the continued importance of understanding the solubility of NO3-cancrinite and related phases. Knowledge of the detailed structure of actual phases in the tank waste helps with thermodynamic modeling of tank conditions and waste processing. PMID:15382874

  13. Optimisation of nitrate reductase enzyme activity to synthesise silver nanoparticles.

    Science.gov (United States)

    Khodashenas, Bahareh; Ghorbani, Hamid Reza

    2016-06-01

    Today, the synthesis of silver nanoparticles (Ag NPs) is very common since it has many applications in different areas. The synthesis of these nanoparticles is done by means of physical, chemical, or biological methods. However, due to its inexpensive and environmentally friendly features, the biological method is more preferable. In the present study, using nitrate reductase enzyme available in the Escherichia coli (E. coli) bacterium, the biosynthesis of Ag NPs was investigated. In addition, the activity of the nitrate reductase enzyme was optimised by changing its cultural conditions, and the effects of silver nitrate (AgNO3) concentration and enzyme amount on nanoparticles synthesis were studied. Finally, the produced nanoparticles were studied using ultraviolet -visible (UV-Vis) spectrophotometer, dynamic light scattering technique, and transmission electron microscopy. UV-Visible spectrophotometric study showed the characteristic peak for Ag NPs at wavelength 405-420 nm for 1 mM metal precursor solution (AgNO3) with 1, 5, 10, and 20 cc supernatant and 435 nm for 0.01M AgNO3 with 20 cc supernatant. In this study, it was found that there is a direct relationship between the AgNO3 concentration and the size of produced Ag NPs. PMID:27256897

  14. Tandem electrochemical desalination-potentiometric nitrate sensing for seawater analysis.

    Science.gov (United States)

    Cuartero, Maria; Crespo, Gastón A; Bakker, Eric

    2015-08-18

    We report on a methodology for the direct potentiometric determination of nitrate in seawater by in-line coupling to an electrochemical desalination module. A microfluidic custom-fabricated thin layer flat cell allows one to electrochemically reduce the chloride concentration of seawater more than 100-fold, from 600 mM down to ∼2.8 mM. The desalinator operates by the exhaustive electrochemical plating of the halides from the thin layer sample onto a silver element as silver chloride, which is coupled to the transfer of the counter cations across a permselective ion-exchange membrane to an outer solution. As a consequence of suppressing the major interference of an ion-exchanger based membrane, the 80 μL desalinated sample plug is passed to a potentiometric flow cell of 13 μL volume. The potentiometric sensor is composed of an all-solid-state nitrate selective electrode based on lipophilic carbon nanotubes (f-MWCNTs) as an ion-to-electron transducer (slope of -58.9 mV dec(-1), limit of detection of 5 × 10(-7) M, and response time of 5 s in batch mode) and a miniaturized reference electrode. Nitrate is successfully determined in desalinated seawater using ion chromatography as the reference method. It is anticipated that this concept may form an attractive platform for in situ environmental analysis of a variety of ions that normally suffer from interference by the high saline level of seawater. PMID:26201537

  15. Neurobehavioral Assessment of Rats Exposed to Yttrium Nitrate during Development

    Institute of Scientific and Technical Information of China (English)

    LI Chen Xi; MA Chuan; FANG Hai Qin; ZHI Yuan; YU Zhou; XU Hai Bin; JIA Xu Dong

    2015-01-01

    Objective The aim of this study was to assess the effects of yttrium nitrate on neurobehavioral development in Sprague-Dawley rats. Methods Dams were orally exposed to 0, 5, 15, or 45 mg/kg daily of yttrium nitrate from gestation day (GD) 6 to postnatal day (PND) 21. Body weight and food consumption were monitored weekly. Neurobehavior was assessed by developmental landmarks and reflexes, motor activity, hot plate, Rota-rod and cognitive tests. Additionally, brain weights were measured on PND 21 and 70. Results No significant difference was noted among all groups for maternal body weight and food consumption. All yttrium-exposed offspring showed an increase in body weight on PND 21;however, no significant difference in body weight for exposed pups versus controls was observed 2 weeks or more after the yttrium solution was discontinued. The groups given 5 mg/kg daily decreased significantly in the duration of female forelime grip strength and ambulation on PND 13. There was no significant difference between yttrium-exposed offspring and controls with respect to other behavioral ontogeny parameters and postnatal behavioral test results. Conclusion Exposure of rats to yttrium nitrate in concentrations up to 45 mg/kg daily had no adverse effects on their neurobehavioral development.

  16. Design of one evaporation system for uranyl nitrate solution

    International Nuclear Information System (INIS)

    The authors propose an instant evaporation system with recirculation of the concentrated solution to raise the concentration from 50 to 1500 g of uranium per litre of solution. The capacity of the plant is to be 14.1 kg of uranium per hour. The main equipment used in the system is as follows: 1. Ring-type heat exchanger, for increasing the temperature of the mixture of fresh and recirculated solution from 80 to 1150C; 2. Separation tank, in which instant evaporation is carried out. The absolute pressure inside the tank will be 500 mmHg, with steam separation from a concentrated (78.5 wt.%) uranyl nitrate solution; 3. Desuperheater-condenser of horizontal tubular type for condensing water vapour and recovering any uranyl nitrate that may have been entrained; 4. Storage tank for the concentrate, with a capacity for one day's normal operation, and a heating coil to prevent crystallization of the concentrated solution; 5. Two storage tanks for feed and condensate with capacity for one day's normal operation; 6. Supporting structure for the above components. Virtually all equipment in contact with the uranyl nitrate solution will be made of 304 stainless steel. Saturated steam at 143.30C will be required. The cost of the proposed system is $543 030.00. (author)

  17. Nitrate source apportionment in a subtropical watershed using Bayesian model

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liping; Han, Jiangpei; Xue, Jianlong; Zeng, Lingzao [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058 (China); Shi, Jiachun, E-mail: jcshi@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058 (China); Wu, Laosheng, E-mail: laowu@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058 (China); Jiang, Yonghai [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012 (China)

    2013-10-01

    Nitrate (NO{sub 3}{sup −}) pollution in aquatic system is a worldwide problem. The temporal distribution pattern and sources of nitrate are of great concern for water quality. The nitrogen (N) cycling processes in a subtropical watershed located in Changxing County, Zhejiang Province, China were greatly influenced by the temporal variations of precipitation and temperature during the study period (September 2011 to July 2012). The highest NO{sub 3}{sup −} concentration in water was in May (wet season, mean ± SD = 17.45 ± 9.50 mg L{sup −1}) and the lowest concentration occurred in December (dry season, mean ± SD = 10.54 ± 6.28 mg L{sup −1}). Nevertheless, no water sample in the study area exceeds the WHO drinking water limit of 50 mg L{sup −1} NO{sub 3}{sup −}. Four sources of NO{sub 3}{sup −} (atmospheric deposition, AD; soil N, SN; synthetic fertilizer, SF; manure and sewage, M and S) were identified using both hydrochemical characteristics [Cl{sup −}, NO{sub 3}{sup −}, HCO{sub 3}{sup −}, SO{sub 4}{sup 2−}, Ca{sup 2+}, K{sup +}, Mg{sup 2+}, Na{sup +}, dissolved oxygen (DO)] and dual isotope approach (δ{sup 15}N–NO{sub 3}{sup −} and δ{sup 18}O–NO{sub 3}{sup −}). Both chemical and isotopic characteristics indicated that denitrification was not the main N cycling process in the study area. Using a Bayesian model (stable isotope analysis in R, SIAR), the contribution of each source was apportioned. Source apportionment results showed that source contributions differed significantly between the dry and wet season, AD and M and S contributed more in December than in May. In contrast, SN and SF contributed more NO{sub 3}{sup −} to water in May than that in December. M and S and SF were the major contributors in December and May, respectively. Moreover, the shortcomings and uncertainties of SIAR were discussed to provide implications for future works. With the assessment of temporal variation and sources of NO{sub 3}{sup −}, better

  18. Observation of nitrate coatings on atmospheric mineral dust particles

    Directory of Open Access Journals (Sweden)

    W. J. Li

    2009-03-01

    Full Text Available Nitrate compounds have received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of ambient nitrate-coated mineral particles on an individual particle scale. In this study, sample collection was conducted during brown haze and dust episodes between 24 May and 21 June 2007 in Beijing, northern China. Sizes, morphologies, and compositions of 332 mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM coupled with energy-dispersive X-ray (EDX microanalyses. Structures of some mineral particles were verified using selected-area electron diffraction (SAED. TEM observation indicates that approximately 90% of the collected mineral particles are covered by visible coatings in haze samples whereas only 5% are coated in the dust sample. 92% of the analyzed mineral particles are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The majority of coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with small amounts of sulfates and chlorides. These nitrate coatings are strongly correlated with the presence of alkaline mineral components (e.g., calcite and dolomite. CaSO4 particles with diameters from 10 to 500 nm were also detected in the coatings including Ca(NO32 and Mg(NO32. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3. Mineral particles that acquire hygroscopic nitrate coatings tend to be more spherical and larger, enhancing their light scattering and CCN activity, both of which have cooling effects on

  19. Nitrate source apportionment in a subtropical watershed using Bayesian model

    International Nuclear Information System (INIS)

    Nitrate (NO3−) pollution in aquatic system is a worldwide problem. The temporal distribution pattern and sources of nitrate are of great concern for water quality. The nitrogen (N) cycling processes in a subtropical watershed located in Changxing County, Zhejiang Province, China were greatly influenced by the temporal variations of precipitation and temperature during the study period (September 2011 to July 2012). The highest NO3− concentration in water was in May (wet season, mean ± SD = 17.45 ± 9.50 mg L−1) and the lowest concentration occurred in December (dry season, mean ± SD = 10.54 ± 6.28 mg L−1). Nevertheless, no water sample in the study area exceeds the WHO drinking water limit of 50 mg L−1 NO3−. Four sources of NO3− (atmospheric deposition, AD; soil N, SN; synthetic fertilizer, SF; manure and sewage, M and S) were identified using both hydrochemical characteristics [Cl−, NO3−, HCO3−, SO42−, Ca2+, K+, Mg2+, Na+, dissolved oxygen (DO)] and dual isotope approach (δ15N–NO3− and δ18O–NO3−). Both chemical and isotopic characteristics indicated that denitrification was not the main N cycling process in the study area. Using a Bayesian model (stable isotope analysis in R, SIAR), the contribution of each source was apportioned. Source apportionment results showed that source contributions differed significantly between the dry and wet season, AD and M and S contributed more in December than in May. In contrast, SN and SF contributed more NO3− to water in May than that in December. M and S and SF were the major contributors in December and May, respectively. Moreover, the shortcomings and uncertainties of SIAR were discussed to provide implications for future works. With the assessment of temporal variation and sources of NO3−, better agricultural management practices and sewage disposal programs can be implemented to sustain water quality in subtropical watersheds. - Highlights: • Nitrate concentration in water displayed

  20. Terahertz spectroscopy and solid-state density functional theory simulations of the improvised explosive oxidizers potassium nitrate and ammonium nitrate.

    Science.gov (United States)

    Witko, Ewelina M; Buchanan, William D; Korter, Timothy M

    2011-11-10

    Terahertz spectroscopy provides a noninvasive and nondestructive method for detecting and identifying concealed explosives. In this work, the room-temperature and cryogenic terahertz spectra of two common improvised explosive oxidizers, namely, potassium nitrate (KN) and ammonium nitrate (AN), are presented, along with detailed solid-state density functional theory (DFT) analyses of the crystalline structures and spectral features. At both 294 and 78 K, KN exhibits two terahertz absorption features below 100 cm(-1) that have been assigned through DFT simulations to arise from hindered nitrate rotations in the KN-II crystalline polymorph. The terahertz spectrum of AN exhibits a pronounced temperature dependence. The 294 K spectrum is free of any absorptions, whereas the 78 K spectrum consists of several narrow and intense peaks. The origin of this large difference is the polymorphic transition that occurs during cooling of AN, where room-temperature AN-IV is converted to AN-V at 255 K. The 78 K terahertz spectrum of AN is assigned here to various ion rotations and translations in the AN-V polymorph lattice. The analysis of the room-temperature AN-IV terahertz spectrum proved to be more complicated. The solid-state DFT simulations predicted that the room-temperature crystal structure of AN is not very well described using the standard Pmmn space-group symmetry as previously believed. The AN-IV polymorph actually belongs to the Pmn2(1) space group, and the perceived Pmmn symmetry results from vibrational averaging through nitrate rotations. This newly observed Pmn2(1) crystal symmetry for room-temperature AN is the reason for the absence of absorption features in the 294 K terahertz spectrum of AN and provides new insight into the polymorphic transitions of this ionic solid. PMID:22007790