Perchlorate isotope forensics

USGS Publications Warehouse

Böhlke, J.K.; Sturchio, N.C.; Gu, B.; Horita, J.; Brown, G.M.; Jackson, W.A.; Batista, J.; Hatzinger, P.B.

2005-01-01

Perchlorate has been detected recently in a variety of soils, waters, plants, and food products at levels that may be detrimental to human health. These discoveries have generated considerable interest in perchlorate source identification. In this study, comprehensive stable isotope analyses ( 37Cl/35Cl and 18O/17O/ 16O) of perchlorate from known synthetic and natural sources reveal systematic differences in isotopic characteristics that are related to the formation mechanisms. In addition, isotopic analyses of perchlorate extracted from groundwater and surface water demonstrate the feasibility of identifying perchlorate sources in contaminated environments on the basis of this technique. Both natural and synthetic sources of perchlorate have been identified in water samples from some perchlorate occurrences in the United States by the isotopic method. ?? 2005 American Chemical Society.

Anionic carbonato and oxalato cobalt(III) nitrogen mustard complexes.

PubMed

Craig, Peter R; Brothers, Penelope J; Clark, George R; Wilson, William R; Denny, William A; Ware, David C

2004-02-21

Synthetic approaches to cobalt(III) complexes [Co(L)(L')2] containing the bidentate dialkylating nitrogen mustard N,N-bis(2-chloroethyl)-1,2-ethanediamine (L = dce) together with anionic ancilliary ligands (L') which are either carbonato (CO3(2-)), oxalato (ox2-), bis(2-hydroxyethyl)dithiocarbamato (bhedtc-), 2-pyridine carboxylato (pico-) or 2-pyrazine carboxylato (pyzc-) were investigated. Synthetic routes were developed using the related amines N,N-diethyl-1,2-ethanediamine (dee) and 1,2-ethanediamine (en). The complexes [Co(CO3)2(L)]- (L = dee 1, dce 2), [Co(ox)2(L)]- (L = dee 3, dce 4), [Co(bhedtc)2(dee)]+ 5, [Co(bhedtc)2(en)]+ 6, mer-[Co(pico)3], mer-[Co(pyzc)]3 7 and [Co(pico)2(dee)]+ 8 were prepared and were characterised by IR, UV-Vis, 1H and 13C[1H] NMR spectroscopy, mass spectrometry and cyclic voltammetry. [Co(bhedtc)2(en)]BPh4 6b and trans(O)-[Co(pico)2(dee)]ClO4 8 were characterised by X-ray crystallography. In vitro biological tests were carried out on complexes 1-4 in order to assess the degree to which coordination of the mustard to cobalt attenuated its cytotoxicity, and the differential toxicity in air vs. nitrogen.

Synthesis and Base Hydrolysis of a Cobalt(III) Complex Coordinated by a Thioether Ligand

ERIC Educational Resources Information Center

Roecker, Lee

2008-01-01

A two-week laboratory experiment for students in advanced inorganic chemistry is described. Students prepare and characterize a cobalt(III) complex coordinated by a thioether ligand during the first week of the experiment and then study the kinetics of Co-S bond cleavage in basic solution during the second week. The synthetic portion of the…

A comparative study on the binding of single and double chain surfactant-cobalt(III) complexes with bovine serum albumin

NASA Astrophysics Data System (ADS)

Vignesh, G.; Sugumar, K.; Arunachalam, S.; Vignesh, S.; Arthur James, R.

2013-09-01

The comparative binding effect of single and double aliphatic chain containing surfactant-cobalt(III) complexes cis-[Co(bpy)2(DA)2](ClO4)3ṡ2H2O (1), cis-[Co(bpy)2(DA)Cl](ClO4)2ṡ2H2O (2), cis-[Co(phen)2(CA)2](ClO4)3ṡ2H2O (3), and cis-[Co(phen)2(CA)Cl](ClO4)2ṡ2H2O (4) with bovine serum albumin (BSA) under physiological condition was analyzed by steady state, time resolved fluorescence, synchronous, three-dimensional fluorescence, UV-Visible absorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of BSA through a static mechanism. The binding constants (Kb) and the number of binding sites were calculated and binding constant values are found in the range of 104-105 M-1. The results indicate that compared to single chain complex, double chain surfactant-cobalt(III) complex interacts strongly with BSA. Also the sign of thermodynamic parameters (ΔG°, ΔH°, and ΔS°) indicate that all the complexes interact with BSA through hydrophobic force. The binding distance (r) between complexes and BSA was calculated using Förster non-radiation energy transfer theory and found to be less than 7 nm. The results of synchronous, three dimensional fluorescence and circular dichroism spectroscopic methods indicate that the double chain surfactant-cobalt(III) complexes changed the conformation of the protein considerably than the respective single chain surfactant-cobalt(III) complexes. Antimicrobial studies of the complexes showed good activities against pathogenic microorganisms.

Nonaqueous capillary electrophoresis with indirect electrochemical detection.

PubMed

Matysik, Frank-Michael; Marggraf, Daniela; Gläser, Petra; Broekaert, José A C

2002-11-01

Nonaqueous capillary electrophoresis (NACE) which makes use of organic solvents in place of conventional aqueous electrophoresis buffers is gaining increasing importance among modern separation techniques. Recently, it has been shown that amperometric detection in conjunction with acetonitrile-based NACE offers an extended accessible potential range and an enhanced long-term stability of the amperometric responses generated at solid electrodes. The present contribution takes advantage of the latter aspect to develop reliable systems for NACE with indirect electrochemical detection (IED). In this context, several compounds such as (ferrocenylmethyl)trimethylammonium perchlorate, tris(1,10-phenanthroline)cobalt(III) perchlorate and bis(1,4,7-triazacyclononane)nickel(II) perchlorate were studied regarding their suitability to act as electroactive buffer additives for IED in NACE. The performance characteristics for the respective buffer systems were evaluated. Tetraalkylammonium perchlorates served as model compounds for the optimization of the NACE-IED system. Target analytes choline and acetylcholine could easily be separated and determined by means of NACE-IED. In the case of a buffer system containing 10(-4) M tris(1,10-phenanthroline)cobalt(III) perchlorate the limits of detection were 2.5 x 10(-7) M and 4.6 x 10(-7) M for choline and acetylcholine, respectively. With the elaborated analytical procedure choline could be determined in pharmaceutical preparations.

Synthesis of porous sheet-like Co{sub 3}O{sub 4} microstructure by precipitation method and its potential applications in the thermal decomposition of ammonium perchlorate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu Shanshan; Jing Xiaoyan; Liu Jingyuan

2013-01-15

Porous sheet-like cobalt oxide (Co{sub 3}O{sub 4}) were successfully synthesized by precipitation method combined with calcination of cobalt hydroxide precursors. The structure, morphology and porosity properties of the products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption-desorption measurement. The as-prepared sheet-like microstructures were approximately 2-3 {mu}m in average diameter, and the morphology of the cobalt hydroxide precursors was retained after the calcination process. However, it appeared a large number of uniform pores in the sheets after calcination. In order to calculate the potential catalytic activity, the thermal decomposition of ammoniummore » perchlorate (AP) has been analyzed, in which cobalt oxide played a role of an additive and the porous sheet-like Co{sub 3}O{sub 4} microstructures exhibited high catalytic performance and considerable decrease in the thermal decomposition temperature of AP. Moreover, a formation mechanism for the sheet-like microstructures has been discussed. - Graphical abstract: Porous sheet-like Co{sub 3}O{sub 4} were synthesized by facile precipitation method combined with calcination of {beta}-Co(OH){sub 2} precursors. Thermogravimetric-differential scanning calorimetric analysis indicates potential catalytic activity in the thermal decomposition of ammonium perchlorate. Highlights: Black-Right-Pointing-Pointer Synthesis of sheet-like {beta}-Co(OH){sub 2} precursors by precipitation method. Black-Right-Pointing-Pointer Porous sheet-like Co{sub 3}O{sub 4} were obtained by calcining {beta}-Co(OH){sub 2} precursors. Black-Right-Pointing-Pointer The possible formation mechanism of porous sheet-like Co{sub 3}O{sub 4} has been discussed. Black-Right-Pointing-Pointer Porous sheet-like Co{sub 3}O{sub 4} decrease the thermal decomposition temperature of ammonium perchlorate.« less

Cytotoxic property of surfactant-cobalt(III) complexes on a human breast cancer cell line.

PubMed

Kumar, Rajendran Senthil; Riyasdeen, Anvarbatcha; Dinesh, Mohanakrishnan; Paul, Christo Preethy; Srinag, Suresh; Krishnamurthy, Hanumanthappa; Arunachalam, Sankaralingam; Akbarsha, Mohammad Abdulkadher

2011-07-01

The cancer chemotherapeutic potential of surfactant-cobalt(III) complexes, cis-[Co(bpy)(2)(C(14)H(29)NH(2))Cl](ClO(4))(2)·3 H(2)O (1) and cis-[Co(phen)(2)(C(14)H(29)NH(2))Cl](ClO(4))(2)·3 H(2)O (2) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) on MCF-7 breast cancer cell was determined adopting MTT assay and specific staining techniques. The complexes affected the viability of the cells significantly and the cells succumbed to apoptosis as seen in the changes in the nuclear morphology and cytoplasmic features. Since the complex 2 appeared to be more potent, further assays were carried out on the complex 2. Single-cell electrophoresis indicated DNA damage. The translocation of phosphatidyl serine and loss of mitochondrial potential was revealed by annexin V-Cy3 staining and JC-1 staining respectively. Western blot analysis revealed up-regulation of pro-apoptotic p53 and down-regulation of anti-apoptotic Bcl-2 protein. Taken together, the surfactant-cobalt(III) complex 2 would be a potential candidate for further investigation for application as a chemotherapeutic for cancers in general and estrogen receptor-positive breast cancer in particular. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure of thiocyanate hydrolase: a new nitrile hydratase family protein with a novel five-coordinate cobalt(III) center.

PubMed

Arakawa, Takatoshi; Kawano, Yoshiaki; Kataoka, Shingo; Katayama, Yoko; Kamiya, Nobuo; Yohda, Masafumi; Odaka, Masafumi

2007-03-09

Thiocyanate hydrolase (SCNase) of Thiobacillus thioparus THI115 is a cobalt(III)-containing enzyme catalyzing the degradation of thiocyanate to carbonyl sulfide and ammonia. We determined the crystal structures of the apo- and native SCNases at a resolution of 2.0 A. SCNases in both forms had a conserved hetero-dodecameric structure, (alphabetagamma)(4). Four alphabetagamma hetero-trimers were structurally equivalent. One alphabetagamma hetero-trimer was composed of the core domain and the betaN domain, which was located at the center of the molecule and linked the hetero-trimers with novel quaternary interfaces. In both the apo- and native SCNases, the core domain was structurally conserved between those of iron and cobalt-types of nitrile hydratase (NHase). Native SCNase possessed the post-translationally modified cysteine ligands, gammaCys131-SO(2)H and gammaCys133-SOH like NHases. However, the low-spin cobalt(III) was found to be in the distorted square-pyramidal geometry, which had not been reported before in any protein. The size as well as the electrostatic properties of the substrate-binding pocket was totally different from NHases with respect to the charge distribution and the substrate accessibility, which rationally explains the differences in the substrate preference between SCNase and NHase.

Bioelectrical Perchlorate Remediation

NASA Astrophysics Data System (ADS)

Thrash, C.; Achenbach, L. A.; Coates, J. D.

2007-12-01

Several bioreactor designs are currently available for the ex-situ biological attenuation of perchlorate- contaminated waters and recently, some of these reactor designs were conditionally approved by the California Department of Health Services for application in the treatment of perchlorate contaminated drinking water. However, all of these systems are dependent on the continual addition of a chemical electron donor to sustain microbial activity and are always subject to biofouling and downstream water quality issues. In addition, residual labile electron donor in the reactor effluent can stimulate microbial growth in water distribution systems and contribute to the formation of potentially toxic trihalomethanes during disinfection by chlorination. As part of our ongoing studies into microbial perchlorate reduction we investigated the ability of dissimilatory perchlorate reducing bacteria (DPRB) to metabolize perchlorate using a negatively charged electrode (cathode) in the working chamber of a bioelectrical reactor (BER) as the primary electron donor. In this instance the DPRB use the electrons on the electrode surface either directly or indirectly in the form of electrolytically produced H2 as a source of reducing equivalents for nitrate and perchlorate reduction. As part of this investigation our fed-batch studies showed that DPRB could use electrons from a graphite cathode poised at -500mV (vs. Ag/AgCl) for the reduction of perchlorate and nitrate. We isolated a novel organism, Dechlorospirillum strain VDY, from the cathode surface after 70 days operation which readily reduced 100 mg.L-1 perchlorate in a mediatorless batch bioelectrical reactor (BER) in 6 days. Continuous up-flow BERs (UFBERs) seeded with active cultures of strain VDY continuously treated waters containing 100 mg.L-1 perchlorate with almost 100% efficiency throughout their operation achieving a non-optimized volumetric loading of 60 mg.L-1 reactor volume.day-1. The same UFBERs also treated

Perchlorate as an environmental contaminant.

PubMed

Urbansky, Edward Todd

2002-01-01

Perchlorate anion (ClO4-) has been found in drinking water supplies throughout the southwestern United States. It is primarily associated with releases of ammonium perchlorate by defense contractors, military operations, and aerospace programs. Ammonium perchlorate is used as a solid oxidant in missile and rocket propulsion systems. Traces of perchlorate are found in Chile saltpeter, but the use of such fertilizer has not been associated with large scale contamination. Although it is a strong oxidant, perchlorate anion is very persistent in the environment due to the high activation energy associated with its reduction. At high enough concentrations, perchlorate can affect thyroid gland functions, where it is mistakenly taken up in place of iodide. A safe daily exposure has not yet been set, but is expected to be released in 2002. Perchlorate is measured in environmental samples primarily by ion chromatography. It can be removed by anion exchange or membrane filtration. It is destroyed by some biological and chemical processes. The environmental occurrence, toxicity, analytical chemistry, and remediative approaches are discussed.

High density nonmagnetic cobalt in thin films

NASA Astrophysics Data System (ADS)

Banu, Nasrin; Singh, Surendra; Basu, Saibal; Roy, Anupam; Movva, Hema C. P.; Lauter, V.; Satpati, B.; Dev, B. N.

2018-05-01

Recently high density (HD) nonmagnetic cobalt has been discovered in a nanoscale cobalt thin film, grown on Si(111) single crystal. This form of cobalt is not only nonmagnetic but also superconducting. These promising results have encouraged further investigations of the growth of the nonmagnetic (NM) phase of cobalt. In the original investigation, the cobalt film had a natural cobalt oxide at the top. We have investigated whether the growth of HD NM cobalt layers in the thin film depends on (i) a capping layer on the cobalt film, (ii) the thickness of the cobalt film and (iii) the nature of the substrate on which the cobalt film is grown. The results of such investigations indicate that for cobalt films capped with a thin gold layer, and for various film thicknesses, HD NM cobalt layers are formed. However, instead of a Si substrate, when the cobalt films are grown on oxide substrates, such as silicon oxide or cobalt oxide, HD NM cobalt layers are not formed. The difference is attributed to the nature—crystalline or amorphous—of the substrate.

Hexakis(N,N-dimethyl­formamide-κO)cobalt(II) bis­(perchlorate)

PubMed Central

Eissmann, Frank; Böhle, Tony; Mertens, Florian O. R. L.; Weber, Edwin

2010-01-01

The asymmetric unit of the title complex, [Co(DMF)6](ClO4)2 (DMF = N,N-dimethyl­formamide, C3H7NO), consists of two half complex cations with the Co2+ metal ions located on centers of inversion and two perchlorate anions. In the crystal packing, each Co2+ ion is coordinated by six mol­ecules of DMF in a slightly distorted octa­hedral geometry. The crystal structure is mainly stabilized by coordinative, ionic and C—H⋯O hydrogen-bonding inter­actions. PMID:21580225

Perchlorate Reduction by Yeast for Mars Exploration

NASA Technical Reports Server (NTRS)

Sharma, Alaisha

2015-01-01

Martian soil contains high levels (0.6 percentage by mass) of calcium perchlorate (Ca(ClO4)2), which readily dissociates into calcium and the perchlorate ion (ClO4-) in water. Even in trace amounts, perchlorates are toxic to humans and have been implicated in thyroid dysfunction. Devising methods to lessen perchlorate contamination is crucial to minimizing the health risks associated with human exploration and colonization of Mars. We designed a perchlorate reduction pathway, which sequentially reduces perchlorate to chloride (Cl-) and oxygen (O2), for implementation in the yeast Saccharomyces cerevisiae. Using genes obtained from perchlorate reducing bacteria Azospira oryzae and Dechloromonas aromatica, we plan to assemble this pathway directly within S. cerevisiae through recombinational cloning. A perchlorate reduction pathway would enable S. cerevisiae to lower perchlorate levels and produce oxygen, which may be harvested or used directly by S. cerevisiae for aerobic growth and compound synthesis. Moreover, using perchlorate as an external electron acceptor could improve the efficiency of redox-imbalanced production pathways in yeast. Although several perchlorate reducing bacteria have been identified and utilized in water treatment systems on Earth, the widespread use of S. cerevisiae as a synthetic biology platform justifies the development of a perchlorate reducing strain for implementation on Mars.

Dissimilatory perchlorate reduction: a review.

PubMed

Bardiya, Nirmala; Bae, Jae-Ho

2011-05-20

In the United States anthropogenic activities are mainly responsible for the wide spread perchlorate contamination of drinking water, surface water, groundwater, and soil. Even at microgram levels, perchlorate causes toxicity to flora and fauna and affects growth, metabolism and reproduction in humans and animals. Reports of antithyroid effects of perchlorate and its detection in common food items have raised serious public health concerns, leading to extensive decontamination efforts in recent years. Several physico-chemical removal and biological decontamination processes are being developed. Although promising, ion exchange is a non-selective and incomplete process as it merely transfers perchlorate from water to the resin. The perchlorate-laden spent resins (perchlorate 200-500 mg L(-1)) require regeneration resulting in production of concentrated brine (6-12% NaCl) or caustic waste streams. On the contrary, biological reduction completely degrades perchlorate into O(2) and innocuous Cl(-). High reduction potential of ClO(4)(-)/Cl(-) (E° =∼ 1.28 V) and ClO(3)(-)/Cl(-) pairs (E° =1.03 V) makes these contaminants thermodynamically ideal e(-) acceptors for microbial reduction. In recent years unique dissimilatory perchlorate reducing bacteria have been isolated and detailed studies pertaining to their microbiological, biochemical, genetics and phylogenetic aspects have been undertaken which is the subject of this review article while the various physico-chemical removal and biological reduction processes have been reviewed by others. Copyright © 2010 Elsevier GmbH. All rights reserved.

Molecular design of cage iron(II) and cobalt(II,III) complexes with a second fluorine-enriched superhydrophobic shell.

PubMed

Belov, Alexander S; Zelinskii, Genrikh E; Varzatskii, Oleg A; Belaya, Irina G; Vologzhanina, Anna V; Dolganov, Alexander V; Novikov, Valentin V; Voloshin, Yan Z

2015-02-28

Pentafluorophenylboron-capped iron and cobalt(II) hexachloroclathrochelate precursors were obtained by the one-pot template condensation of dichloroglyoxime with pentafluorophenylboronic acid on iron and cobalt(II) ions under vigorous reaction conditions in trifluoroacetic acid media. These reactive precursors easily undergo nucleophilic substitution with (per)fluoroarylthiolate anions, giving (per)fluoroarylsulfide macrobicyclic complexes with encapsulated iron and cobalt(II) ions; nucleophilic substitution of the cobalt(II) hexachloroclathrochelate precursor with a pentafluorophenylsulfide anion gave the target hexasulfide monoclathrochelate and the mixed-valence Co(III)Co(II)Co(III) bis-clathrochelate as a side product. The complexes obtained were characterized using elemental analysis, MALDI-TOF mass spectrometry, IR, UV-Vis, (57)Fe Mössbauer (for the X-rayed iron complexes), (1)H, (11)B, (13)C and (19)F NMR spectroscopies and by X-ray diffraction; their redox and electrocatalytic behaviors were studied using cyclic voltammetry and gas chromatography. As can be seen from the single-crystal X-ray diffraction data, the second superhydrophobic shell of such caged metal ions is formed by fluorine atoms of both the apical and ribbed (per)fluoroaryl peripheral groups. The main bond distances and chelate N=C-C=N angles in their molecules are similar, but rotational elongation (contraction) along the molecular C3-pseudoaxes, accompanied by changes in the geometry of the corresponding MN6-coordination polyhedra from a trigonal prism to a trigonal antiprism, allowed encapsulating Fe(2+), Co(2+) and Co(3+) ions. The nature of an encapsulated metal ion and its oxidation state affect the M-N bond lengths, and, for cobalt(ii) clathrochelate with an electronic configuration d(7) the Jahn-Teller structural effect is observed as an alternation of the Co-N distances. Pentafluorophenylboron-capped hexachloroclathrochelate precursors, giving stable catalytically active metal

Crystal structure of trans-bis­(ethane-1,2-diamine-κ2 N,N′)bis­(thio­cyanato-κN)chromium(III) perchlorate from synchrotron data

PubMed Central

Moon, Dohyun; Choi, Jong-Ha

2015-01-01

The structure of the title compound, [Cr(NCS)2(C2H8N2)2]ClO4, has been determined from synchroton data. The asymmetric unit consists of one half of a centrosymmetric CrIII complex cation and half of a perchlorate anion with the Cl atom on a twofold rotation axis. The CrIII ion is coordinated by the four N atoms of two ethane-1,2-di­amine (en) ligands in the equatorial plane and two N-bound thio­cyanate (NCS−) anions in a trans-axial arrangement, displaying a slightly distorted octa­hedral geometry with crystallographic inversion symmetry. The Cr—N(en) bond lengths are in the range 2.053 (16)–2.09 (2) Å, while the Cr—N(thio­cyanate) bond length is 1.983 (2) Å. The five-membered en rings are disordered over two sites, with occupancy ratios of 0.522 (16):0.478 (16). Each ClO4 − anion is disordered over two sites with equal occupancy. The crystal structure is stabilized by inter­molecular hydrogen bonds involving the en NH2 groups as donors and perchlorate O and thio­cyanate S atoms as acceptors. PMID:26090142

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wismer, Robert Kingsley

The crystal structure of trans-dicyano triethylene-tetramine cobalt (III) perchlorate (monoclinic, P2 1/n, a = 9.85, b= 22.35, c=6.68 A, β = 100.9°, z = 4, MoKα radiation) has been determined by three-dimensional x-ray analysis.

Coordination of different ligands to copper(II) and cobalt(III) metal centers enhances Zika virus and dengue virus loads in both arthropod cells and human keratinocytes.

PubMed

Dutta, Shovan; Celestine, Michael J; Khanal, Supreet; Huddleston, Alexis; Simms, Colin; Arca, Jessa Faye; Mitra, Amlan; Heller, Loree; Kraj, Piotr J; Ledizet, Michel; Anderson, John F; Neelakanta, Girish; Holder, Alvin A; Sultana, Hameeda

2018-01-01

Trace elements such as copper and cobalt have been associated with virus-host interactions. However, studies to show the effect of conjugation of copper(II) or cobalt(III) metal centers to thiosemicarbazone ligand(s) derived from either food additives or mosquito repellent such as 2-acetylethiazole or citral, respectively, on Zika virus (ZIKV) or dengue virus (serotype 2; DENV2) infections have not been explored. In this study, we show that four compounds comprising of thiosemicarbazone ligand derived from 2-acetylethiazole viz., (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide (acetylethTSC) (compound 1), a copper(II) complex with acetylethTSC as a ligand (compound 2), a thiosemicarbazone ligand-derived from citral (compound 3) and a cobalt(III) complex with a citral-thiosemicarbazone ligand (compound 4) increased DENV2 and ZIKV replication in both mosquito C6/36 cells and human keratinocytes (HaCaT cells). Treatment of both cell lines with compounds 2 or 4 showed increased dengue viral titers at all three tested doses. Enhanced dengue viral plaque formation was also noted at the tested dose of 100μM, suggesting higher production of infectious viral particles. Treatment with the compounds 2 or 4 enhanced ZIKV and DENV2 RNA levels in HeLa cell line and primary cultures of mouse bone marrow derived dendritic cells. Also, pre- or post treatments with conjugated compounds 2 or 4 showed higher loads of ZIKV or DENV2 envelope (E) protein in HaCaT cells. No changes in loads of E-protein were found in ZIKV-infected C6/36 cells, when compounds were treated after infection. In addition, we tested bis(1,10-phenanthroline)copper(II) chloride ([Cu(phen) 2 ]Cl 2 , (compound 5) and tris(1,10-phenanthroline)cobalt(III) chloride ([Co(phen) 3 ]Cl 3 , (compound 6) that also showed enhanced DENV2 loads. Also, we found that copper(II) chloride dehydrate (CuCl 2 ·2H 2 O) or cobalt(II) chloride hexahydrate (CoCl 2 ·6H 2 O) alone had no effects as "free" cations

Carbon-Based Oxamate Cobalt(III) Complexes as Bioenzyme Mimics for Contaminant Elimination in High Backgrounds of Complicated Constituents.

PubMed

Li, Nan; Zheng, Yun; Jiang, Xuemei; Zhang, Ran; Pei, Kemei; Chen, Wenxing

2017-10-12

Complex wastewater with massive components is now a serious environmental issue facing humanity. Selective removal of low-concentration contaminants in mixed constituents holds great promise for increasing water supplies. Bioenzymes like horseradish peroxidase exhibit oxidizing power and selectivity. Here, we manufactured its mimic through immobilizing non-heme oxamate anionic cobalt(III) complex ([Co III (opba)] - , opba = o-phenylenebis(oxamate)) onto pyridine (Py) modified multiwalled carbon nanotubes ([Co III (opba)] - -Py-MWCNTs, MWCNTs = multiwalled carbon nanotubes), where MWCNTs captured substrates and Py functioned as the fifth ligand. We chose typical azo dye (C.I. Acid Red 1) and antibiotic (ciprofloxacin) as model substrates. Without •OH, this catalyst could detoxify target micropollutants efficiently at pH from 8 to 11. It also remained efficient in repetitive tests, and the final products were non-poisonous OH-containing acids. Combined with radical scavenger tests and electron paramagnetic resonance result, we speculated that high-valent cobalt-oxo active species and oxygen atom transfer reaction dominated in the reaction pathway. According to density functional theory calculations, the electron spin density distribution order showed that electron-withdrawing ligand was beneficial for inward pulling the excess electron and lowering the corresponding energy levels, achieving an electrophilic-attack enhancement of the catalyst. With target removal property and recyclability, this catalyst is prospective in water detoxication.

Cobalt Ion Promoted Redox Cascade: A Route to Spiro Oxazine-Oxazepine Derivatives and a Dinuclear Cobalt(III) Complex of an N-(1,4-Naphthoquinone)-o-aminophenol Derivative.

PubMed

Mondal, Sandip; Bera, Sachinath; Maity, Suvendu; Ghosh, Prasanta

2017-11-06

The study discloses that the redox activity of N-(1,4-naphthoquinone)-o-aminophenol derivatives (L R H 2 ) containing a (phenol)-NH-(1,4-naphthoquinone) fragment is notably different from that of a (phenol)-NH-(phenol) precursor. The former is a platform for a redox cascade. L R H 2 is redox noninnocent and exists in Cat-N-(1,4-naphthoquinone)(2-) (L R 2- ) and SQ-N-(1,4-naphthoquinone) (L R •- ) states in the complexes. Reactions of L R H 2 with cobalt(II) salts in MeOH in air promote a cascade affording spiro oxazine-oxazepine derivatives ( OX L R ) in good yields, when R = H, Me, t Bu. Spiro oxazine-oxazepine derivatives are bioactive, and such a molecule has so far not been isolated by a schematic route. In this context this cascade is significant. Dimerization of L R H 2 → OX L R in MeOH is a (6H + + 6e) oxidation reaction and is composed of formations of four covalent bonds and 6-exo-trig and 7-endo-trig cyclization based on C-O coupling reactions, where MeOH is the source of a proton and the ester function. It was established that the active cascade precursor is [(L Me •- )Co III Cl 2 ] (A). Notably, formation of a spiro derivative was not detected in CH 3 CN and the reaction ends up furnishing A. The route of the reaction is tunable by R, when R = NO 2 , it is a (2e + 4H + ) oxidation reaction affording a dinuclear L R 2- complex of cobalt(III) of the type [(L NO2 2- ) 2 Co III 2 (OMe) 2 (H 2 O) 2 ] (1) in good yields. No cascade occurs with zinc(II) ion even in MeOH and produces a L Me •- complex of type [(L Me •- )Zn II Cl 2 ] (2). The intermediate A and 2 exhibit strong EPR signals at g = 2.008 and 1.999, confrming the existence of L Me •- coordinated to low-spin cobalt(III) and zinc(II) ions. The intermediates of L R H 2 → OX L R conversion were analyzed by ESI mass spectrometry. The molecular geometries of OX L R and 1 were confirmed by X-ray crystallography, and the spectral features were elucidated by TD DFT calculations.

A green separation strategy for neodymium (III) from cobalt (II) and nickel (II) using an ionic liquid-based aqueous two-phase system.

PubMed

Chen, Yuehua; Wang, Huiyong; Pei, Yuanchao; Wang, Jianji

2018-05-15

It is significant to develop sustainable strategies for the selective separation of rare earth from transition metals from fundamental and practical viewpoint. In this work, an environmentally friendly solvent extraction approach has been developed to selectively separate neodymium (III) from cobalt (II) and nickel (II) by using an ionic liquid-based aqueous two phase system (IL-ATPS). For this purpose, a hydrophilic ionic liquid (IL) tetrabutylphosphonate nitrate ([P 4444 ][NO 3 ]) was prepared and used for the formation of an ATPS with NaNO 3 . Binodal curves of the ATPSs have been determined for the design of extraction process. The extraction parameters such as contact time, aqueous phase pH, content of phase-formation components of NaNO 3 and the ionic liquid have been investigated systematically. It is shown that under optimal conditions, the extraction efficiency of neodymium (III) is as high as 99.7%, and neodymium (III) can be selectively separated from cobalt (II) and nickel (II) with a separation factor of 10 3 . After extraction, neodymium (III) can be stripped from the IL-rich phase by using dilute aqueous sodium oxalate, and the ILs can be quantitatively recovered and reused in the next extraction process. Since [P 4444 ][NO 3 ] works as one of the components of the ATPS and the extractant for the neodymium, no organic diluent, extra etractant and fluorinated ILs are used in the separation process. Thus, the strategy described here shows potential in green separation of neodymium from cobalt and nickel by using simple IL-based aqueous two-phase system. Copyright © 2018 Elsevier B.V. All rights reserved.

Peptide Biomarkers as Evidence of Perchlorate Biodegradation▿ †

PubMed Central

Bansal, Reema; Crawford, Ronald L.; Paszczynski, Andrzej J.

2011-01-01

Perchlorate is a known health hazard for humans, fish, and other species. Therefore, it is important to assess the response of an ecosystem exposed to perchlorate contamination. The data reported here show that a liquid chromatography-mass spectrometry-based proteomics approach for the detection of perchlorate-reducing enzymes can be used to measure the ability of microorganisms to degrade perchlorate, including determining the current perchlorate degradation status. Signature peptides derived from chlorite dismutase (CD) and perchlorate reductase can be used as biomarkers of perchlorate presence and biodegradation. Four peptides each derived from CD and perchlorate reductase subunit A (PcrA) and seven peptides derived from perchlorate reductase subunit B (PcrB) were identified as signature biomarkers for perchlorate degradation, as these sequences are conserved in the majority of the pure and mixed perchlorate-degrading microbial cultures examined. However, chlorite dismutase signature biomarker peptides from Dechloromonas agitata CKB were found to be different from those in other cultures used and should also be included with selected CD biomarkers. The combination of these peptides derived from the two enzymes represents a promising perchlorate presence/biodegradation biomarker system. The biomarker peptides were detected at perchlorate concentrations as low as 0.1 mM and at different time points both in pure cultures and within perchlorate-reducing environmental enrichment consortia. The peptide biomarkers were also detected in the simultaneous presence of perchlorate and an alternate electron acceptor, nitrate. We believe that this technique can be useful for monitoring bioremediation processes for other anthropogenic environmental contaminants with known metabolic pathways. PMID:21115710

Novel miniaturized sensors for potentiometric batch and flow-injection analysis (FIA) of perchlorate in fireworks and propellants.

PubMed

Almeer, Saeed H M A; Zogby, Ibrahim A; Hassan, Saad S M

2014-11-01

Three planar miniaturized perchlorate membrane sensors (3×5 mm(2)) are prepared using a flexible Kaptan substrate coated with nitron-perchlorate (NT-ClO4) [sensor 1], methylene blue-perchlorate (MB-ClO4) [sensor II] and indium-porphyrin (In-Por) [sensor III] as electroactive materials in PVC membranes plasticized with 2-NPPE. Sensors I, II and III display near-Nernstian response for 1.0×10(-5)-1.0×10(-2), 3.1×10(-5)-1.0×10(-2) and 3.1×10(-6)-1.0×10(-2) mol L(-1) ClO4(-) with lower detection limits of 6.1×10(-6), 6.9×10(-6) and 1.2×10(-6) mol L(-1), and anionic calibration slopes of 50.9±0.4, 48.4±0.4 and 57.7±0.3 mV decade(-1), respectively. Methods for determining perchlorate using these sensors offer many attractive advantages including simplicity, flexibility, cost effectiveness, wide linear dynamic response range (0.1-1000 ppm), low detection limit (<1.2×10(-6) mol L(-1)≡0.1 ppm), small sample test volume (100 μL), safety, short response time (<20 s), long life span (~8 weeks), and extended wide working pH range (4.5-8.0). The sensors show high selectivity in the presence of some inorganic ions (e.g., PO4(3-), SO4(2-), S2O3(2-), NO2(-), NO3(-), N3(-), CN(-), Cl(-), Br(-), I(-)) and automation feasibility. Indium-porphyrin based membrane sensor (sensor III) is used as a detector in a wall-jet flow injection set-up to enable accurate flow injection analysis (FIA) of perchlorate in some fireworks without interferences from the associated reducing agents (sulfur and charcoal), binders (dextrin, lactose), coloring agents (calcium, strontium, copper, iron, sodium), color brighten (linseed oil) and regulators (aluminum flakes) which are commonly used in the formulations. The sensor is also used for perchlorate assessment in some propellant powders. The results fairly agree with data obtained by ion-chromatography. Copyright © 2014 Elsevier B.V. All rights reserved.

Jarosite dissolution rates in perchlorate brine

NASA Astrophysics Data System (ADS)

Legett, Carey; Pritchett, Brittany N.; Elwood Madden, Andrew S.; Phillips-Lander, Charity M.; Elwood Madden, Megan E.

2018-02-01

Perchlorate salts and the ferric sulfate mineral jarosite have been detected at multiple locations on Mars by both landed instruments and orbiting spectrometers. Many perchlorate brines have eutectic temperatures <250 K, and may exist as metastable or stable liquids for extended time periods, even under current Mars surface conditions. Therefore, jarosite-bearing rocks and sediments may have been altered by perchlorate brines. Here we measured jarosite dissolution rates in 2 M sodium perchlorate brine as well as dilute water at 298 K to determine the effects of perchlorate anions on jarosite dissolution rates and potential reaction products. We developed a simple method for determining aqueous iron concentrations in high salinity perchlorate solutions using ultraviolet-visible spectrophotometry that eliminates the risk of rapid oxidation reactions during analyses. Jarosite dissolution rates in 2 M perchlorate brine determined by iron release rate (2.87 × 10-12 ±0.85 × 10-12 mol m-2 s-1) were slightly slower than the jarosite dissolution rate measured in ultrapure (18.2 MΩ cm-1) water (5.06 × 10-12 mol m-2 s-1) using identical methods. No additional secondary phases were observed in XRD analyses of the reaction products. The observed decrease in dissolution rate may be due to lower activity of water (ɑH2O = 0.9) in the 2 M NaClO4 brine compared with ultrapure water (ɑH2O = 1). This suggests that the perchlorate anion does not facilitate iron release, unlike chloride anions which accelerated Fe release rates in previously reported jarosite and hematite dissolution experiments. Since dissolution rates are slower in perchlorate-rich solutions, jarosite is expected to persist longer in perchlorate brines than in dilute waters or chloride-rich brines. Therefore, if perchlorate brines dominate aqueous fluids on the surface of Mars, jarosite may remain preserved over extended periods of time, despite active aqueous processes.

PERCHLORATE IDENTIFICATION IN FERTILIZERS

EPA Science Inventory

Perchlorate has contaminated groundwater, drinking water, and soils at several locations in the United States. The primary source of contamination at sites that have been investigated to date seems to be from industrial and military operations that use perchlorate as an oxidizing...

Chloridobis(ethyl­enediamine-κ2 N,N′)(n-pentyl­amine-κN)cobalt(III) dichloride monhydrate

PubMed Central

Anbalagan, K.; Tamilselvan, M.; Nirmala, S.; Sudha, L.

2009-01-01

The title complex, [CoCl(C5H13N)(C2H8N2)2]Cl2·H2O, comprises one chloridobis(ethyl­enediamine)(n-pentyl­amine)cobalt(III) cation, two chloride counter-anions and a water mol­ecule. The CoIII atom of the complex is hexa­coordinated by five N and one Cl atoms. The five N atoms are from two chelating ethyl­enediamine and one n-pentyl­amine ligands. Neighbouring cations and anions are connected by N—H⋯Cl and N—H⋯O hydrogen bonds to each other and also to the water mol­ecule. PMID:21582753

Modeling In Situ Bioremediation of Perchlorate-Contaminated Groundwater

DTIC Science & Technology

2007-03-01

PERCHLORATE DETECTIONS UNDER THE UCMR PROGRAM ( BRANDHUBER , 2005...AQUIFER WHERE UPFLOW WELL (U) EXTRACTS AND DOWNFLOW WELL ( D ) INJECTS WATER. ASTERISKS REPRESENT STAGNATION POINTS (CUNNINGHAM ET AL., 2004...1 Figure 1.1 Known Perchlorate Releases and Perchlorate Detections under the UCMR Program ( Brandhuber , 2005) Perchlorate is a

Effect of dissimilatory Fe(III) reducers on bio-reduction and nickel-cobalt recovery from Sukinda chromite-overburden.

PubMed

Esther, Jacintha; Panda, Sandeep; Behera, Sunil K; Sukla, Lala B; Pradhan, Nilotpala; Mishra, Barada K

2013-10-01

The effect of an adapted dissimilatory iron reducing bacterial consortium (DIRB) towards bio-reduction of Sukinda chromite overburden (COB) with enhanced recovery of nickel and cobalt is being reported for the first time. The remarkable ability of DIRB to utilize Fe(III) as terminal electron acceptor reducing it to Fe(II) proved beneficial for treatment of COB as compared to previous reports for nickel leaching. XRD studies showed goethite as the major iron-bearing phase in COB. Under facultative anaerobic conditions, goethite was reduced to hematite and magnetite with the exposure of nickel oxide. FESEM studies showed DIRB to be associated with COB through biofilm formation with secondary mineral precipitates of magnetite deposited as tiny globular clusters on the extra polymeric substances. The morphological and mineralogical changes in COB, post DIRB application, yielded a maximum of 68.5% nickel and 80.98% cobalt in 10 days using 8M H2SO4. Copyright © 2013 Elsevier Ltd. All rights reserved.

Stable Isotope Systematics of Martian Perchlorate

NASA Astrophysics Data System (ADS)

Martin, P.; Farley, K. A.; Archer, D., Jr.; Atreya, S. K.; Conrad, P. G.; Eigenbrode, J. L.; Fairen, A.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Malespin, C.; Ming, D. W.; Navarro-Gonzalez, R.; Sutter, B.

2015-12-01

Chlorine isotopic compositions in HCl released during evolved gas analysis (EGA) runs have been detected by the Sample Analysis at Mars (SAM) instrument on the Curiosity rover ranging from approximately -9‰ to -50‰ δ37Cl, with two spatially and isotopically separated groups of samples averaging -15‰ and -45‰. These extremely low values are the first such detection of any known natural material; common terrestrial values very rarely exceed ±5‰, and the most extreme isotopic signature yet detected elsewhere in the solar system are values of around +24‰ on the Moon. The only other known location in the solar system with large negative chlorine isotopes is the Atacama Desert, where perchlorate with -14‰ δ37Cl has been detected. The Atacama perchlorate has unusual Δ17O signatures associated with it, indicating a formation mechanism involving O3, which suggests an atmospheric origin of the perchlorate and associated large isotopic anomalies. Identification of non-zero positive Δ17O signatures in the O2 released during EGA runs would allow definitive evidence for a similar process having occurred on Mars. Perchlorate is thought to be the most likely source of HCl in EGA runs due to the simultaneous onset of O2 release. If perchlorate is indeed the HCl source, atmospheric chemistry could be responsible for the observed isotopic anomalies, with variable extents of perchlorate production producing the isotopic variability. However, chloride salts have also been observed to release HCl upon heating; if the timing of O2 release is merely coincidental, observed HCl could be coming from chlorides. At thermodynamic equilibrium, the fractionation factor of perchlorate reduction is 0.93, meaning that differing amounts of post-deposition reduction of isotopically normal perchlorate to chloride could account for the highly variable Cl isotopes. Additionally, post-deposition reduction could account for the difference between the two Cl isotopic groups if perchlorate

PERCHLORATE CROP INTERACTIONS VIA CONTAMINATED IRRIGATION WATER

EPA Science Inventory

Perchlorate has contaminated water and sods at several locations in the United States. Perchlorate is water soluble, exceedingly mobile in aqueous systems, and can persist for many decades under typical ground- and surface water conditions. Perchlorate is of concern because of un...

Novel biomarkers of perchlorate exposure in zebrafish

USGS Publications Warehouse

Mukhi, S.; Carr, J.A.; Anderson, T.A.; Patino, R.

2005-01-01

Perchlorate inhibits iodide uptake by thyroid follicles and lowers thyroid hormone production. Although several effects of perchlorate on the thyroid system have been reported, the utility of these pathologies as markers of environmental perchlorate exposures has not been adequately assessed. The present study examined time-course and concentration-dependent effects of perchlorate on thyroid follicle hypertrophy, colloid depletion, and angiogenesis; alterations in whole-body thyroxine (T4) levels; and somatic growth and condition factor of subadult and adult zebrafish. Changes in the intensity of the colloidal T4 ring previously observed in zebrafish also were examined immunohistochemically. Three-month-old zebrafish were exposed to ammonium perchlorate at measured perchlorate concentrations of 0, 11, 90, 1,131, and 11,480 ppb for 12 weeks and allowed to recover in clean water for 12 weeks. At two weeks of exposure, the lowest-observed-effective concentrations (LOECs) of perchlorate that induced angiogenesis and depressed the intensity of colloidal T4 ring were 90 and 1,131 ppb, respectively; other parameters were not affected (whole-body T4 was not determined at this time). At 12 weeks of exposure, LOECs for colloid depletion, hypertrophy, angiogenesis, and colloidal T4 ring were 11,480, 1,131, 90, and 11 ppb, respectively. All changes were reversible, but residual effects on angiogenesis and colloidal T4 ring intensity were still present after 12 weeks of recovery (LOEC, 11,480 ppb). Whole-body T 4 concentration, body growth (length and weight), and condition factor were not affected by perchlorate. The sensitivity and longevity of changes in colloidal T4 ring intensity and angiogenesis suggest their usefulness as novel markers of perchlorate exposure. The 12-week LOEC for colloidal T4 ring is the lowest reported for any perchlorate biomarker in aquatic vertebrates. ?? 2005 SETAC.

PERCHLORATE AS AN ENVIRONMENTAL CONTAMINANT

EPA Science Inventory

Perchlorate anion (C104) has been found in drinking water supplies throughout the southwestern United States. I t is primarily associated with releases of ammonium perdhlorate by defense contractors, military operations, and aerospace programs. Ammonium perchlorate is used as ...

Simultaneous removal of perchlorate and energetic compounds in munitions wastewater by zero-valent iron and perchlorate-respiring bacteria.

PubMed

Ahn, Se Chang; Hubbard, Brian; Cha, Daniel K; Kim, Byung J

2014-01-01

Ammonium perchlorate is one of the main constituents in Army's insensitive melt-pour explosive, PAX-21 in addition to RDX and 2,4-dinitroanisole (DNAN). The objective of this study is to develop an innovative treatment process to remove both perchlorate and energetic compounds simultaneously from PAX-21 production wastewater. It was hypothesized that the pretreatment of PAX-21 wastewater with zero-valent iron (ZVI) would convert energetic compounds to products that are more amenable for biological oxidation and that these products serve as electron donors for perchlorate-reducing bacteria. Results of batch ZVI reduction experiments showed that DNAN was completely reduced to 2,4-diaminoanisole and RDX was completely reduced to formaldehyde. Anaerobic batch biodegradation experiments showed that perchlorate (30 mg L(-1)) in ZVI-treated PAX-21 wastewater was decreased to an undetectable level after 5 days. Batch biodegradation experiments also confirmed that formaldehyde in ZVI-treated wastewater was the primary electron donor for perchlorate-respiring bacteria. The integrated iron-anaerobic bioreactor system was effective in completely removing energetic compounds and perchlorate from the PAX-21 wastewater without adding an exogenous electron donor. This study demonstrated that ZVI pretreatment not only removed energetic compounds, but also transformed energetic compounds to products that can serve as the source of electrons for perchlorate-respiring bacteria.

Bio-reduction of free and laden perchlorate by the pure and mixed perchlorate reducing bacteria: Considering the pH and coexisting nitrate.

PubMed

Shang, Yanan; Wang, Ziyang; Xu, Xing; Gao, Baoyu; Ren, Zhongfei

2018-08-01

Pure bacteria cell (Azospira sp. KJ) and mixed perchlorate reducing bacteria (MPRB) were employed for decomposing the free perchlorate in water as well as the laden perchlorate on surface of quaternary ammonium wheat residuals (QAWR). Results indicated that perchlorate was decomposed by the Azospira sp. KJ prior to nitrate while MPRB was just the reverse. Bio-reduction of laden perchlorate by Azospira sp. KJ was optimal at pH 8.0. In contrast, bio-reduction of laden perchlorate by MPRB was optimal at pH 7.0. Generally, the rate of perchlorate reduction was controlled by the enzyme activity of PRB. In addition, perchlorate recovery (26.0 mg/g) onto bio-regenerated QAWR by MPRB was observed with a small decrease as compared with that (31.1 mg/g) by Azospira sp. KJ at first 48 h. Basically, this study is expected to offer some different ideas on bio-regeneration of perchlorate-saturated adsorbents using biological process, which may provide the economically alternative to conventional methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modeling In Situ Bioremediation of Perchlorate-Contaminated Groundwater

NASA Astrophysics Data System (ADS)

Goltz, M. N.; Secody, R. E.; Huang, J.; Hatzinger, P. B.

2007-12-01

Perchlorate-contaminated groundwater is a significant national problem. An innovative technology was recently developed which uses a pair of dual-screened treatment wells to mix an electron donor into perchlorate- contaminated groundwater in order to effect in situ bioremediation of the perchlorate by indigenous perchlorate reducing bacteria (PRB) without the need to extract the contaminated water from the subsurface. The two treatment wells work in tandem to establish a groundwater recirculation zone in the subsurface. Electron donor is added and mixed into perchlorate-contaminated groundwater flowing through each well. The donor serves to stimulate biodegradation of the perchlorate by PRB in bioactive zones that form adjacent to the injection screens of the treatment wells. In this study, a model that simulates operation of the technology was calibrated using concentration data obtained from a field-scale technology evaluation project at a perchlorate-contaminated site. The model simulates transport of perchlorate, the electron donor (citrate, for this study), and competing electron acceptors (oxygen and nitrate) in the groundwater flow field induced by operation of the treatment well pair. A genetic algorithm was used to derive a set of best-fit model parameters to describe the perchlorate reduction kinetics in this field-scale evaluation project. The calibrated parameter values were then used to predict technology performance. The model qualitatively predicted the salient characteristics of the observed data. It appears the model may be a useful tool for designing and operating this technology at other perchlorate-contaminated sites.

Perchlorate Exposure Through Water and Milk in Istanbul.

PubMed

Can, Ozge; Blount, Ben; Valentin-Blasini, Liza; Erdemgil, Yigit; Uzunoglu, Deniz; Aksoy, Murat; Coskun, Abdurrahman; Serteser, Mustafa; Unsal, Ibrahim; Ozpinar, Aysel

2016-09-01

Perchlorate is a chemical pollutant that inhibits iodide uptake and may possibly impair thyroid function. Our previous study found widespread perchlorate exposure in non-pregnant, non-lactating, healthy women residing in Istanbul. The aim of this study is to assess the relative amounts of perchlorate exposure attributable to consumption of municipal water, bottled water and boxed milk available in Istanbul. Only trace levels of perchlorate were found in treated municipal water (58 % detectable, mean = 0.13 µg/L, maximum = 0.75 µg/L) and bottled water (7.4 % detectable, mean = perchlorate (mean = 4.53 µg/L; maximum = 6.21 µg/L). Median perchlorate exposure attributable to water and milk (0.007 µg/kg/day) is small compared both to the reference dose (0.7 µg/kg/day) and to total perchlorate exposure (0.13 µg/kg/day) in Istanbul. Therefore, additional studies are needed to identify the major sources of perchlorate exposure in Istanbul.

Atmospheric Production of Perchlorate on Earth and Mars

NASA Astrophysics Data System (ADS)

Claire, M.; Catling, D. C.; Zahnle, K. J.

2009-12-01

Natural production and preservation of perchlorate on Earth occurs only in arid environments. Isotopic evidence suggests a strong role for atmospheric oxidation of chlorine species via pathways including ozone or its photochemical derivatives. As the Martian atmosphere is both oxidizing and drier than the driest places on Earth, we propose an atmospheric origin for the Martian perchlorates measured by NASA's Phoenix Lander. A variety of hypothetical formation pathways can be proposed including atmospheric photochemical reactions, electrostatic discharge, and gas-solid reactions. Here, we investigate gas phase formation pathways using a 1-D photochemical model (Catling et al. 2009, accepted by JGR). Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we start with a study of the means to produce Atacama perchlorate. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. These results are sensitive to estimated reaction rates for ClO3 species. The feasibility of gas phase production for the Atacama provides justification for further investigations of gas phase photochemistry as a possible source for Martian perchlorate. In addition to the Atacama results, we will present a preliminary study incorporating chlorine chemistry into an existing Martian photochemical model (Zahnle et al. JGR 2008).

Biotechnological Applications of Microbial (Per)chlorate Reduction.

PubMed

Wang, Ouwei; Coates, John D

2017-11-24

While the microbial degradation of a chloroxyanion-based herbicide was first observed nearly ninety years ago, only recently have researchers elucidated the underlying mechanisms of perchlorate and chlorate [collectively, (per)chlorate] respiration. Although the obvious application of these metabolisms lies in the bioremediation and attenuation of (per)chlorate in contaminated environments, a diversity of alternative and innovative biotechnological applications has been proposed based on the unique metabolic abilities of dissimilatory (per)chlorate-reducing bacteria (DPRB). This is fueled in part by the unique ability of these organisms to generate molecular oxygen as a transient intermediate of the central pathway of (per)chlorate respiration. This ability, along with other novel aspects of the metabolism, have resulted in a wide and disparate range of potential biotechnological applications being proposed, including enzymatic perchlorate detection; gas gangrene therapy; enhanced xenobiotic bioremediation; oil reservoir bio-souring control; chemostat hygiene control; aeration enhancement in industrial bioreactors; and, biogenic oxygen production for planetary exploration. While previous reviews focus on the fundamental science of microbial (per)chlorate reduction (for example see Youngblut et al., 2016), here, we provide an overview of the emerging biotechnological applications of (per)chlorate respiration and the underlying organisms and enzymes to environmental and biotechnological industries.

Perchlorate Clinical Pharmacology and Human Health: A Review

PubMed Central

Soldin, Offie Porat; Braverman, Lewis E.; Lamm, Steven H.

2013-01-01

Summary Potassium perchlorate has been used at various times during the last 50 years to treat hyperthyroidism. Since World War II ammonium perchlorate has been used as a propellant for rockets. In 1997, the assay sensitivity for perchlorate in water was improved from 0.4 mg/L (ppm) to 4 µg/L (ppb). As a result, public water supplies in Southern California were found to contain perchlorate ions in the range of 5 to 8 ppb, and those in Southern Nevada were found to contain 5 to 24 ppb. Research programs have been developed to assess the safety or risk from these exposures and to assist state and regulatory agencies in setting a reasonable safe level for perchlorate in drinking water. This report reviews the evidence on the human health effects of perchlorate exposure. Perchlorate is a competitive inhibitor of iodine uptake. All of its pharmacologic effects at current therapeutic levels or lower are associated with inhibition of the sodium-iodide symporter (NIS) on the thyroid follicular cell membrane. A review of the medical and occupational studies has been undertaken to identify perchlorate exposure levels at which thyroid hormone levels may be reduced or thyrotropin levels increased. This exposure level may begin in the 35 to 100 mg/d range. Volunteer studies have been designed to determine the exposure levels at which perchlorate begins to affect iodine uptake in humans. Such effects may begin at levels of approximately 1 mg/d. Environmental studies have assessed the thyroidal health of newborns and adults at current environmental exposures to perchlorate and have concluded that the present levels appear to be safe. Whereas additional studies are underway both in laboratory animals and in the field, it appears that a safe level can be established for perchlorate in water and that regulatory agencies and others are now trying to determine that level. PMID:11477312

(Per)chlorate Reduction by the Thermophilic Bacterium Moorella perchloratireducens sp. nov., Isolated from Underground Gas Storage▿

PubMed Central

Balk, Melike; van Gelder, Ton; Weelink, Sander A.; Stams, Alfons J. M.

2008-01-01

A thermophilic bacterium, strain An10, was isolated from underground gas storage with methanol as a substrate and perchlorate as an electron acceptor. Cells were gram-positive straight rods, 0.4 to 0.6 μm in diameter and 2 to 8 μm in length, growing as single cells or in pairs. Spores were terminal with a bulged sporangium. The temperature range for growth was 40 to 70°C, with an optimum at 55 to 60°C. The pH optimum was around 7. The salinity range for growth was between 0 and 40 g NaCl liter−1 with an optimum at 10 g liter−1. Strain An10 was able to grow on CO, methanol, pyruvate, glucose, fructose, cellobiose, mannose, xylose, and pectin. The isolate was able to respire with (per)chlorate, nitrate, thiosulfate, neutralized Fe(III) complexes, and anthraquinone-2,6-disulfonate. The G+C content of the DNA was 57.6 mol%. On the basis of 16S rRNA analysis, strain An10 was most closely related to Moorella thermoacetica and Moorella thermoautotrophica. The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell extracts. Strain An10 is the first thermophilic and gram-positive bacterium with the ability to use (per)chlorate as a terminal electron acceptor. PMID:17981952

Isotopic Discrimination of Perchlorate Sources in Ground Water

NASA Astrophysics Data System (ADS)

Bohlke, J.; Hatzinger, P. B.; Sturchio, N. C.; Gu, B.; Jackson, W. A.; Abbene, I. J.

2007-12-01

Perchlorate has been detected in ground water and drinking water in many areas of the U.S. during the past decade. Sources of potential perchlorate enrichment in ground water include releases from past military activities, fireworks manufacture and display, fertilizer applications, discarded road flares, and local atmospheric deposition. Here we present analyses of stable isotopes (δ37Cl, δ18O, and Δ17O) of dissolved perchlorate, along with other supporting environmental tracer data, from selected occurrences in ground water in the U.S. The isotope data indicate that both synthetic and natural perchlorate are present in ground water, and that multiple sources are present locally in some areas. The sampled ground waters generally were oxic and the perchlorate isotopes generally were not affected substantially by biodegradation. In some areas, natural perchlorate, with Δ17O = +7 to +10 ‰, can be attributed to agricultural applications of atmospherically derived natural nitrate fertilizer imported from South America (Atacama Desert, Chile). In at least one agricultural area in New York, concentrations of perchlorate increase with depth and ground-water age, possibly because of decreasing application rates of Atacama nitrate fertilizer and(or) decreasing perchlorate concentrations in the imported fertilizer products in recent years.

Maternal perchlorate exposure in pregnancy and altered birth outcomes.

PubMed

Rubin, Rainbow; Pearl, Michelle; Kharrazi, Martin; Blount, Benjamin C; Miller, Mark D; Pearce, Elizabeth N; Valentin-Blasini, Liza; DeLorenze, Gerald; Liaw, Jane; Hoofnagle, Andrew N; Steinmaus, Craig

2017-10-01

At high medicinal doses perchlorate is known to decrease the production of thyroid hormone, a critical factor for fetal development. In a large and uniquely exposed cohort of pregnant women, we recently identified associations between environmental perchlorate exposures and decreased maternal thyroid hormone during pregnancy. Here, we investigate whether perchlorate might be associated with birthweight or preterm birth in the offspring of these women. Maternal urinary perchlorate, serum thyroid hormone concentrations, birthweight, gestational age, and urinary nitrate, thiocyanate, and iodide were collected in 1957 mother-infant pairs from San Diego County during 2000-2003, a period when the county's water supply was contaminated with perchlorate. Associations between perchlorate exposure and birth outcomes were examined using linear and logistic regression analyses adjusted for maternal age, weight, race/ethnicity, and other factors. Perchlorate was not associated with birth outcomes in the overall population. However, in analyses confined to male infants, log 10 maternal perchlorate concentrations were associated with increasing birthweight (β=143.1gm, p=0.01), especially among preterm births (β=829.1g, p<0.001). Perchlorate was associated with male preterm births ≥2500g (odds ratio=3.03, 95% confidence interval=1.09-8.40, p-trend=0.03). Similar associations were not seen in females. This is the first study to identify associations between perchlorate and increasing birthweight. Further research is needed to explore the differences we identified related to infant sex, preterm birth, and other factors. Given that perchlorate exposure is ubiquitous, and that long-term impacts can follow altered birth outcomes, future research on perchlorate could have widespread public health importance. Copyright © 2017 Elsevier Inc. All rights reserved.

Atmospheric origins of perchlorate on Mars and in the Atacama

NASA Astrophysics Data System (ADS)

Catling, D. C.; Claire, M. W.; Zahnle, K. J.; Quinn, R. C.; Clark, B. C.; Hecht, M. H.; Kounaves, S.

2010-01-01

Isotopic studies indicate that natural perchlorate is produced on Earth in arid environments by the oxidation of chlorine species through pathways involving ozone or its photochemical products. With this analogy, we propose that the arid environment on Mars may have given rise to perchlorate through the action of atmospheric oxidants. A variety of hypothetical pathways can be proposed including photochemical reactions, electrostatic discharge, and gas-solid reactions. Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we made a preliminary study of the means to produce Atacama perchlorate to help shed light on the origin of Martian perchlorate. We investigated gas phase pathways using a 1-D photochemical model. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. The feasibility of gas phase production for the Atacama provides justification for future investigations of gas phase photochemistry as a possible source for Martian perchlorate.

PERCHLORATE PHYTOREMEDIATION USING HARDWOOD TREES AND VASCULAR PLANTS

EPA Science Inventory

Perchlorate has contaminated water and soils at several locations in the United States. Perchlorate is
water soluble, exceedingly mobile in aqueous systems, and can persist for many decades under typical ground and surface water conditions. Perchlorate is of concern because of...

Cobalt, manganese, and iron near the Hawaiian Islands: A potential concentrating mechanism for cobalt within a cyclonic eddy and implications for the hybrid-type trace metals

NASA Astrophysics Data System (ADS)

Noble, Abigail E.; Saito, Mak A.; Maiti, Kanchan; Benitez-Nelson, Claudia R.

2008-05-01

The vertical distributions of cobalt, iron, and manganese in the water column were studied during the E-Flux Program (E-Flux II and III), which focused on the biogeochemistry of cold-core cyclonic eddies that form in the lee of the Hawaiian Islands. During E-Flux II (January 2005) and E-Flux III (March 2005), 17 stations were sampled for cobalt ( n=147), all of which demonstrated nutrient-like depletion in surface waters. During E-Flux III, two depth profiles collected from within a mesoscale cold-core eddy, Cyclone Opal, revealed small distinct maxima in cobalt at ˜100 m depth and a larger inventory of cobalt within the eddy. We hypothesize that this was due to a cobalt concentrating effect within the eddy, where upwelled cobalt was subsequently associated with sinking particulate organic carbon (POC) via biological activity and was released at a depth coincident with nearly complete POC remineralization [Benitez-Nelson, C., Bidigare, R.R., Dickey, T.D., Landry, M.R., Leonard, C.L., Brown, S.L., Nencioli, F., Rii, Y.M., Maiti, K., Becker, J.W., Bibby, T.S., Black, W., Cai, W.J., Carlson, C.A., Chen, F., Kuwahara, V.S., Mahaffey, C., McAndrew, P.M., Quay, P.D., Rappe, M.S., Selph, K.E., Simmons, M.P., Yang, E.J., 2007. Mesoscale eddies drive increased silica export in the subtropical Pacific Ocean. Science 316, 1017-1020]. There is also evidence for the formation of a correlation between cobalt and soluble reactive phosphorus during E-Flux III relative to the E-Flux II cruise that we suggest is due to increased productivity, implying a minimum threshold of primary production below which cobalt-phosphate coupling does not occur. Dissolved iron was measured in E-Flux II and found in somewhat elevated concentrations (˜0.5 nM) in surface waters relative to the iron depleted waters of the surrounding Pacific [Fitzwater, S.E., Coale, K.H., Gordon, M.R., Johnson, K.S., Ondrusek, M.E., 1996. Iron deficiency and phytoplankton growth in the equatorial Pacific. Deep

Simultaneous detection of perchlorate and bromate using rapid high-performance ion exchange chromatography-tandem mass spectrometry and perchlorate removal in drinking water.

PubMed

West, Danielle M; Mu, Ruipu; Gamagedara, Sanjeewa; Ma, Yinfa; Adams, Craig; Eichholz, Todd; Burken, Joel G; Shi, Honglan

2015-06-01

Perchlorate and bromate occurrence in drinking water causes health concerns due to their effects on thyroid function and carcinogenicity, respectively. The purpose of this study was threefold: (1) to advance a sensitive method for simultaneous rapid detection of perchlorate and bromate in drinking water system, (2) to systematically study the occurrence of these two contaminants in Missouri drinking water treatment systems, and (3) to examine effective sorbents for minimizing perchlorate in drinking water. A rapid high-performance ion exchange chromatography-tandem mass spectrometry (HPIC-MS/MS) method was advanced for simultaneous detection of perchlorate and bromate in drinking water. The HPIC-MS/MS method was rapid, required no preconcentration of the water samples, and had detection limits for perchlorate and bromate of 0.04 and 0.01 μg/L, respectively. The method was applied to determine perchlorate and bromate concentrations in total of 23 selected Missouri drinking water treatment systems during differing seasons. The water systems selected include different source waters: groundwater, lake water, river water, and groundwater influenced by surface water. The concentrations of perchlorate and bromate were lower than or near to method detection limits in most of the drinking water samples monitored. The removal of perchlorate by various adsorbents was studied. A cationic organoclay (TC-99) exhibited effective removal of perchlorate from drinking water matrices.

Perchlorate contamination in Chile: Legacy, challenges, and potential solutions.

PubMed

Vega, Marcela; Nerenberg, Robert; Vargas, Ignacio T

2018-07-01

This paper reviews the unique situation of perchlorate contamination in Chile, including its sources, presence in environmental media and in the human population, and possible steps to mitigate its health impacts. Perchlorate is a ubiquitous water contaminant that inhibits thyroid function. Standards for drinking water range from 2 to 18 µg L -1 in United States and Europe. A major natural source of perchlorate contamination is Chile saltpeter, found in the Atacama Desert. High concentrations of perchlorate have presumably existed in this region, in soils, sediments, surface waters and groundwaters, for millions of years. As a result of this presence, and the use of Chile saltpeter as a nitrogen fertilizer, perchlorate in Chile has been found at concentrations as high as 1480 µg L -1 in drinking water, 140 µg/kg -1 in fruits, and 30 µg L -1 in wine. Health studies in Chile have shown concentrations of 100 µg L - 1 in breast milk and 20 µg L -1 in neonatal serum. It is important to acknowledge perchlorate as a potential health concern in Chile, and assess mitigation strategies. A more thorough survey of perchlorate in Chilean soils, sediments, surface waters, groundwaters, and food products can help better assess the risks and potentially develop standards. Also, perchlorate treatment technologies should be more closely assessed for relevance to Chile. The Atacama Desert is a unique biogeochemical environment, with millions of years of perchlorate exposure, which can be mined for novel perchlorate-reducing microorganisms, potentially leading to new biological treatment processes for perchlorate-containing waters, brines, and fertilizers. Copyright © 2018 Elsevier Inc. All rights reserved.

(Per)chlorate in Biology on Earth and Beyond.

PubMed

Youngblut, Matthew D; Wang, Ouwei; Barnum, Tyler P; Coates, John D

2016-09-08

Respiration of perchlorate and chlorate [collectively, (per)chlorate] was only recognized in the last 20 years, yet substantial advances have been made in our understanding of the underlying metabolisms. Although it was once considered solely anthropogenic, pervasive natural sources, both terrestrial and extraterrestrial, indicate an ancient (per)chlorate presence across our solar system. These discoveries stimulated interest in (per)chlorate microbiology, and the application of advanced approaches highlights exciting new facets. Forward and reverse genetics revealed new information regarding underlying molecular biology and associated regulatory mechanisms. Structural and functional analysis characterized core enzymes and identified novel reaction sequences. Comparative genomics elucidated evolutionary aspects, and stress analysis identified novel response mechanisms to reactive chlorine species. Finally, systems biology identified unique metabolic versatility and novel mechanisms of (per)chlorate respiration, including symbiosis and a hybrid enzymatic-abiotic metabolism. While many published studies focus on (per)chlorate and their basic metabolism, this review highlights seminal advances made over the last decade and identifies new directions and potential novel applications.

PHYTOREMEDIATION OF PERCHLORATE BY TOBACCO PLANTS

EPA Science Inventory

Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in the plant tissues. The objective of this research was to determine the effectiveness of tobacco plants in phytoremediation, a technology that employs plants to degrade,...

Perchlorate in Water Supplies: Sources, Exposures, and Health Effects

PubMed Central

Steinmaus, Craig M.

2016-01-01

Perchlorate exposure occurs from ingestion of natural or manmade perchlorate in food or water. Perchlorate is used in a variety of industrial products including missile fuel, fireworks, and fertilizers, and industrial contamination of drinking water supplies has occurred in a number of areas. Perchlorate blocks iodide uptake into the thyroid, and decreases the production of thyroid hormone, a critical hormone for metabolism, neurodevelopment, and other physiologic functions. Occupational and clinical dosing studies have not identified clear adverse effects, but may be limited by small sample sizes, short study durations, and the inclusion of mostly healthy adults. Expanding evidence suggests that young children, pregnant women, fetuses, and people co-exposed to similarly acting agents may be especially susceptible to perchlorate. Given the ubiquitous nature of perchlorate exposure, and the importance of thyroid hormone for brain development, studying the impact of perchlorate on human health could have far-reaching public health implications. PMID:27026358

The Microbiology of Perchlorate in the Environment

NASA Astrophysics Data System (ADS)

Coates, J. D.

2007-12-01

In the last decade perchlorate has been identified as an important groundwater component that poses potential health threat. Although primarily sourced anthropogenically, many recent studies have identified significant natural pools throughout the US and the natural mechanisms of its synthesis remain a mystery. As such, the true perchlorate concentrations naturally present in the environment are still unknown making its regulation problematic. Because of its solubility and non-reactivity the fate and transport of perchlorate in the environment is primarily a function of microbial activity. In the last seven years more than forty specialized perchlorate respiring organisms have been identified and characterized. These dissimilatory perchlorate reducing bacteria (DPRB) are metabolically diverse and environmental populations tend to be dominated by two primary genotypes, the Dechloromonas and the Azospira species. As such, the majority of our understanding of this metabolism is based on these organisms. These organisms are readily found in soil and sedimentary environments and often associate with the rhizosphere. Recent research has demonstrated an accumulation of these organisms along plant roots suggesting their catabolism of root exudates and molecular studies has demonstrated their existence as endophytic infections of the stem and leaves of actively growing Brachypodium grass plants although their exact role under these conditions is unknown. These microorganisms are generally not nutritionally fastidious and vitamin supplementation is unnecessary for growth although molybdenum is a required trace element for perchlorate reduction. The Dechloromonas and Azospira species generally grow optimally at pH values near neutrality in freshwater environments. Even so, recent field studies have shown that related deep-branching members of these genera often predominate in sites of adverse pH or salinity with some species being capable of growth and perchlorate respiration

Perchlorate adsorption and desorption on activated carbon and anion exchange resin.

PubMed

Yoon, In-Ho; Meng, Xiaoguang; Wang, Chao; Kim, Kyoung-Woong; Bang, Sunbaek; Choe, Eunyoung; Lippincott, Lee

2009-05-15

The mechanisms of perchlorate adsorption on activated carbon (AC) and anion exchange resin (SR-7 resin) were investigated using Raman, FTIR, and zeta potential analyses. Batch adsorption and desorption results demonstrated that the adsorption of perchlorate by AC and SR-7 resin was reversible. The reversibility of perchlorate adsorption by the resin was also proved by column regeneration test. Solution pH significantly affected perchlorate adsorption and the zeta potential of AC, while it did not influence perchlorate adsorption and the zeta potential of resin. Zeta potential measurements showed that perchlorate was adsorbed on the negatively charged AC surface. Raman spectra indicated the adsorption resulted in an obvious position shift of the perchlorate peak, suggesting that perchlorate was associated with functional groups on AC at neutral pH through interactions stronger than electrostatic interaction. The adsorbed perchlorate on the resin exhibited a Raman peak at similar position as the aqueous perchlorate, indicating that perchlorate was adsorbed on the resin through electrostatic attraction between the anion and positively charged surface sites.

Perchlorate in the Great Lakes: isotopic composition and origin.

PubMed

Poghosyan, Armen; Sturchio, Neil C; Morrison, Candice G; Beloso, Abelardo D; Guan, Yunbin; Eiler, John M; Jackson, W Andrew; Hatzinger, Paul B

2014-10-07

Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ(18)O, Δ(17)O) and chlorine (δ(37)Cl) along with the abundance of the radioactive isotope (36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 μg per liter. δ(37)Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas δ(18)O values range from -4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ(17)O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∼+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The (36)Cl/Cl ratio of perchlorate varies widely from 7.4 × 10(-12) (Lake Ontario) to 6.7 × 10(-11) (Lake Superior). These (36)ClO4(-) abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high (36)ClO4(-) abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of (36)Cl-enriched perchlorate deposited during the period of elevated atmospheric (36)Cl activity following thermonuclear bomb tests in the Pacific Ocean.

ADSORPTION CHARACTERISTICS OF PERCHLORATE IN SOILS

EPA Science Inventory

Perchlorate(CI04) is an oxyanion that originates as a contaminant in ground and surface waters from the dissolution of ammonium, potassium, magnesium or sodium salts. Perchlorate is mainly used in solid rocket fuels, explosives, and military batteries. Because of its potential ha...

Luminescence enhancement of terbium(III) perchlorate by 2,2'-dipyridyl on bis(benzylsulfinyl)methane complex and luminescence mechanism.

PubMed

Feng, Shu-Yan; Li, Wen-Xian; Guo, Feng; Cao, Xiao-Fang

2014-11-01

A novel ternary complex, Tb(2)L4 · L'·(ClO4)6 · 8H2O, has been synthesized using bis(benzylsulfinyl)methane as the first ligand L and 2,2'-dipyridyl as the second ligand L'. The ternary complex was characterized by element analysis, molar conductivity, coordination titration analysis, infrared, thermogravimetric-differential scanning calorimetric and ultraviolet spectra. The results indicated that the composition of the complex was Tb2 L4 · L'·(ClO4)6 · 8H2O (L = C(6)H(5)CH(2) SOCH(2)SOCH(2)C(6)H(5); L' = Dipy). Fourier transform infrared results revealed that the perchlorate group was bonded with the Tb(III) ion by the oxygen atom, and the coordination was bidentate. The fluorescent spectra illustrated that the complex displayed characteristic fluorescence in the solid state. After the introduction of the second ligand, 2,2-dipyridyl, the relative emission intensity and fluorescence lifetime of the ternary complex Tb(2)L(4) · L'·(ClO(4))(6) · 8H2O were enhanced compared to the binary complex TbL(2.5)(ClO4)3 · 3H2O. This indicated that the presence of both organic ligand bis(benzylsulfinyl)methane and the second ligand 2,2-dipyridyl could sensitize the fluorescence intensity of Tb(III) ion, and introduction of the 2,2-dipyridyl group resulted in an enhancement of the fluorescence of the Tb(III) ternary rare earth complex. The strongest characteristic fluorescence emission intensity of the ternary complex was 9.36 times that of the binary complex. The phosphorescence spectra and fluorescence lifetime of the complex were also measured. Copyright © 2014 John Wiley & Sons, Ltd.

Crystal structure of tin(II) perchlorate trihydrate

PubMed Central

Hennings, Erik; Schmidt, Horst; Köhler, Martin; Voigt, Wolfgang

2014-01-01

The title compound, [Sn(H2O)3](ClO4)2, was synthesized by the redox reaction of copper(II) perchlorate hexa­hydrate and metallic tin in perchloric acid. Both the trigonal–pyramidal [Sn(H2O)3]2+ cations and tetra­hedral perchlorate anions lie on crystallographic threefold axes. In the crystal, the cations are linked to the anions by O—H⋯O hydrogen bonds, generating (001) sheets. PMID:25552969

Ruthenium(III) catalyzed oxidation of sugar alcohols by dichloroisocyanuric acid—A kinetic study

NASA Astrophysics Data System (ADS)

Lakshman Kumar, Y.; Venkata Nadh, R.; Radhakrishnamurti, P. S.

2016-02-01

Kinetics of ruthenium(III) catalyzed oxidation of biologically important sugar alcohols (myo-inositol, D-sorbitol, and D-mannitol) by dichloroisocyanuric acid was carried out in aqueous acetic acid—perchloric medium. The reactions were found to be first order in case of oxidant and ruthenium(III). Zero order was observed with the concentrations of sorbitol and mannitol whereas, a positive fractional order was found in the case of inositol concentration. An inverse fractional order was observed with perchloric acid in oxidation of three substrates. Arrhenius parameters were calculated and a plausible mechanism was proposed.

PHYTOTRANSFORMATION OF PERCHLORATE USING PARROT-FEATHER

EPA Science Inventory

Perchlorate is an oxvanion that has been extensively is a strong oxidizing
agent in solid rocket fuel. Contamination of groundwater has occurred as the result of Perchlorate use. Standard disposal practices during the 1950s through the 1970s did not reflect the current knowled...

Part I. Cobalt thiolate complexes modeling the active site of cobalt nitrile hydratase. Part II. Formation of inorganic nanoparticles on protein scaffolding in Escherichia coli glutamine synthetase

NASA Astrophysics Data System (ADS)

Kung, Irene Yuk Man

Part I. A series of novel cobalt dithiolate complexes with mixed imine/amine ligand systems is presented here as electronic and structural models for the active site in the bacterial enzyme class, nitrile hydratase (NHase). Pentadentate cobalt(II) complexes with S2N 3 ligand environments are first studied as precursors to the more relevant cobalt(III) complexes. Adjustment of the backbone length by removal of a methylene group increases the reactivity of the system; whereas reduction of the two backbone imine bonds to allow free rotation about those bonds may decrease reactivity. Reactivity change due to the replacement of the backbone amine proton with a more sterically challenging methyl group is not yet clear. Upon oxidation, the monocationic pentadentate cobalt(III) complex, 1b, shows promising reactivity similar to that of NHase. The metal's open coordination site allows reversible binding of the endogenous, monoanionic ligands, N 3- and NCS-. Oxygenation of the thiolate sulfur atoms by exposure to O2 and H2O 2 produces sulfenate and sulfinate ligands in complex 8, which resembles the crystal structure of "deactivated" Fe NHase. However, its lack of reactivity argues against the oxygenated enzyme structure as the active form. Six-coordinate cobalt(III) complexes with S2N4 amine/amine ligand systems are also presented as analogues of previously reported iron(III) compounds, which mimic the spectroscopic properties of Fe NHase. The cobalt complexes do not seem to similarly model Co NHase. However, the S = 0 cobalt(III) center can be spectroscopically silent and difficult to detect, making comparison with synthetic models using common techniques hard. Part II. Dodecameric Escherichia coli glutamine synthetase mutant, E165C, stacks along its six-fold axis to produce tubular nanostructures in the presence of some divalent metal ions, as does the wild type enzyme. The centrally located, engineered Cys-165 residues appear to bind to various species and may serve as

ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS AND TOBACCO PRODUCTS

EPA Science Inventory

Previous field and laboratory studies with vascular plants have shown that perchlorate is transported from perchlorate fortified soils and is accumulated in the plant tissues and organs. This paper reports results of initial investigations on the accumulation of perchlorate in t...

DETERMINATION OF PERCHLORATE IN TOBACCO PLANTS AND TOBACCO PRODUCTS

EPA Science Inventory

Previous field and laboratory studies with vascular plants have shown that perchlorate is transported from perchlorate fortified soils and is accumulated in the plant tissues and organs. This paper reports results of initial investigations on the accumulation of perchlorate in t...

Temperature dependent viscosity of cobalt ferrite / ethylene glycol ferrofluids

NASA Astrophysics Data System (ADS)

Kharat, Prashant B.; Somvanshi, Sandeep B.; Kounsalye, Jitendra S.; Deshmukh, Suraj S.; Khirade, Pankaj P.; Jadhav, K. M.

2018-04-01

In the present work, cobalt ferrite / ethylene glycol ferrofluid is prepared in 0 to 1 (in the step of 0.2) volume fraction of cobalt ferrite nanoparticles synthesized by co-precipitation method. The XRD results confirmed the formation of single phase spinel structure. The Raman spectra have been deconvoluted into individual Lorentzian peaks. Cobalt ferrite has cubic spinel structure with Fd3m space group. FT-IR spectra consist of two major absorption bands, first at about 586 cm-1 (υ1) and second at about 392 cm-1 (υ2). These absorption bands confirm the formation of spinel-structured cobalt ferrite. Brookfield DV-III viscometer and programmable temperature-controlled bath was used to study the relationship between viscosity and temperature. Viscosity behavior with respect to temperature has been studied and it is revealed that the viscosity of cobalt ferrite / ethylene glycol ferrofluids increases with an increase in volume fraction of cobalt ferrite. The viscosity of the present ferrofluid was found to decrease with increase in temperature.

Thermal and Evolved Gas Analysis of Magnesium Perchlorate: Implications for Perchlorates in Soils at the Mars Phoenix Landing Site

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Morris, R.V.; Lauer, H. V.; Sutter, B.; Golden, D.C.; Boynton, W.V.

2009-01-01

Perchlorate salts were discovered in the soils around the Phoenix landing site on the northern plains of Mars [1]. Perchlorate was detected by an ion selective electrode that is part of the MECA Wet Chemistry Laboratory (WCL). The discovery of a mass 32 fragment (likely 02) by the Thermal and Evolved-Gas Analyzer (TEGA) provided additional confirmation of a strong oxidizer in the soils around the landing site. The purpose of this paper is to evaluate the thermal and evolved gas behavior of perchlorate salts using TEGA-like laboratory testbed instruments. TEGA ovens were fabricated from high purity Ni. Hence, an additional objective of this paper is to determine the effects that Ni might have on the evolved gas behavior of perchlorate salts.

Mesophilic, Circumneutral Anaerobic Iron Oxidation as a Remediation Mechanism for Radionuclides, Nitrate and Perchlorate

NASA Astrophysics Data System (ADS)

Bose, S.; Thrash, J. C.; Coates, J. D.

2008-12-01

Iron oxidation is a novel anaerobic metabolism where microorganisms obtain reducing equivalents from the oxidization of Fe(II) and assimilate carbon from organic carbon compounds or CO2. Recent evidence indicates that in combination with the activity of dissimilatory Fe(III)-reducing bacteria, anaerobic microbial Fe(II) oxidation can also contribute to the global iron redox cycle. Studies have also proved that Fe(II)- oxidation is ubiquitous in diverse environments and produce a broad range of insoluble iron forms as end products. These biogenic Fe(III)-oxides and mixed valence Fe minerals have a very high adsorption capacity of heavy metals and radionuclides. Adsorption and immobilization by these biogenic Fe phases produced at circumneutral pH, is now considered a very effective mode of remediation of radionuclides like Uranium, especially under variable redox conditions. By coupling soluble and insoluble Fe(II) oxidation with nitrate and perchlorate as terminal electron acceptors in-situ, anaerobic Fe-oxidation can also be used for environmental cleanup of Fe through Fe-mineral precipitation, as well as nitrate and perchlorate through reduction. Coupling of Fe as the sole electron and energy source to the reduction of perchlorate or nitrate boosts the metabolism without building up biomass hence also taking care of biofouling. To understand the mechanisms by which microorganisms can grow at circumneutral pH by mesophilic, anaerobic iron oxidation and the ability of microorganisms to reduce nitrate and perchlorate coupled to iron oxidation recent work in our lab involved the physiological characterization of Dechlorospirillum strain VDY which was capable of anaerobic iron-oxidation with either nitrate or perchlorate serving as terminal electron acceptor. Under non-growth conditions, VDY oxidized 3mM Fe(II) coupled to nitrate reduction, and 2mM Fe(II) coupled to perchlorate reduction, in 24 hours. It contained a copy of the RuBisCO cbbM subunit gene which was

Perchlorate as an emerging contaminant in soil, water and food.

PubMed

Kumarathilaka, Prasanna; Oze, Christopher; Indraratne, S P; Vithanage, Meththika

2016-05-01

Perchlorate ( [Formula: see text] ) is a strong oxidizer and has gained significant attention due to its reactivity, occurrence, and persistence in surface water, groundwater, soil and food. Stable isotope techniques (i.e., ((18)O/(16)O and (17)O/(16)O) and (37)Cl/(35)Cl) facilitate the differentiation of naturally occurring perchlorate from anthropogenic perchlorate. At high enough concentrations, perchlorate can inhibit proper function of the thyroid gland. Dietary reference dose (RfD) for perchlorate exposure from both food and water is set at 0.7 μg kg(-1) body weight/day which translates to a drinking water level of 24.5 μg L(-1). Chromatographic techniques (i.e., ion chromatography and liquid chromatography mass spectrometry) can be successfully used to detect trace level of perchlorate in environmental samples. Perchlorate can be effectively removed by wide variety of remediation techniques such as bio-reduction, chemical reduction, adsorption, membrane filtration, ion exchange and electro-reduction. Bio-reduction is appropriate for large scale treatment plants whereas ion exchange is suitable for removing trace level of perchlorate in aqueous medium. The environmental occurrence of perchlorate, toxicity, analytical techniques, removal technologies are presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Potentiometric perchlorate determination at nanomolar concentrations in vegetables.

PubMed

Leoterio, Dilmo M S; Paim, Ana Paula S; Belian, Mônica F; Galembeck, André; Lavorante, André F; Pinto, Edgar; Amorim, Célia G; Araújo, Alberto N; Montenegro, Maria C B S M

2017-07-15

In this work, an expeditious method based on the multi-commutated flow-analysis concept with potentiometric detection is proposed to perform determinations of the emergent contaminant perchlorate in vegetable matrices down to nanomolar concentration. To accomplish the task, a tubular shaped potentiometric sensor selective to perchlorate ion was constructed with a PVC membrane containing 12mmol/kg of the polyamine bisnaphthalimidopropyl-4,4'-diaminodiphenylmethane and 2-nitrophenyl phenyl ether 68% (w/w) as plasticizer casted on a conductive epoxy resin. Under optimal flow conditions, the sensor responded linearly in the concentration range of 6.3×10 -7 -1.0×10 -3 mol/L perchlorate. In order to extend the determinations to lower concentrations (4.6(±1.3)×10 -10 mol/L perchlorate), a column packed with 70mg of sodium 2,5,8,11,14-pentaoxa-1-silacyclotetradecane-polymer was coupled to the flow-system thus enabling prior pre-concentration of the perchlorate. The proposed procedure provides a simpler alternative for the determination of perchlorate in foods, nowadays only allowed by sophisticated and expensive equipment and laborious methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Interaction between perchlorate and iodine in the metamorphosis of Hyla versicolor

USGS Publications Warehouse

Sparling, D.; Harvey, G.; Nzengung, V.; ,

2003-01-01

Perchlorate (ClO4-) is a water-soluble, inorganic anion that is often combined with ammonium, potassium or other cations for use in industry and agriculture. Ammonium perchlorate, for example, is a potent oxidizer and is used in various military applications including rocket fuel. It has also been found in an historically widely used fertilizer, Chilean nitrate and in other fertilizers. It has been found in ground and surface waters of over 30 states and is considered a human health risk. Because of its similar atomic radius and volume, perchlorate competes with iodide for thyroid uptake and storage and thereby inhibits production of thyroid hormones. Amphibians may be particularly affected by perchlorate because they rely on the thyroid for metamorphosis. This study exposed early larval Hyla versicolor to concentrations of perchlorate ranging from 2.2 to 50 ppm to determine the effects of perchlorate on a native amphibian. In addition, three controls, 0 perchlorate, 0 perchlorate with 0.10 ppm iodide (C + I) and 50 ppm perchlorate + 0.10 ppm iodide (50 + I) were tested. Mortality (< 11% with all treatments) and growth appeared to be unaffected by perchlorate. Inhibition of development started with 2.2 ppm perchlorate and little or no development occurred at 22.9 ppm and above. This inhibition was particularly apparent at the latter stages of development including hindlimb formation and metamorphosis. The estimated EC50 for total inhibition of metamorphosis at 70 days of treatment was 3.63 ppm. There was no evidence of inhibition of development with the 50 + I, C + I, or controls, indicating that the presence of small concentrations of iodide could counter the effects of perchlorate. When tadpoles that had been inhibited by perchlorate were subsequently treated with iodide, development through prometamorphosis progressed but mortality was very high.

Interaction between perchlorate and iodine in the metamorphosis of Hyla versicolor

USGS Publications Warehouse

Sparling, D.W.; Harvey, G.; Nzengung, V.; Linder, Gregory L.; Krest, Sherry K.; Sparling, Donald W.; Little, Edward E.

2003-01-01

Perchlorate (ClO4-) is a water-soluble, inorganic anion that is often combined with ammonium, potassium or other cations for use in industry and agriculture. Ammonium perchlorate, for example, is a potent oxidizer and is used in various military applications including rocket fuel. It has also been found in an historically widely used fertilizer, Chilean nitrate and in other fertilizers. It has been found in ground and surface waters of over 30 states and is considered a human health risk. Because of its similar atomic radius and volume, perchlorate competes with iodide for thyroid uptake and storage and thereby inhibits production of thyroid hormones. Amphibians may be particularly affected by perchlorate because they rely on the thyroid for metamorphosis. This study exposed early larval Hyla versicolor to concentrations of perchlorate ranging from 2.2 to 50 ppm to determine the effects of perchlorate on a native amphibian. In addition, three controls, 0 perchlorate, 0 perchlorate with 0.10 ppm iodide (C + I) and 50 ppm perchlorate + 0.10 ppm iodide (50 + I) were tested. Mortality (<11% with all treatments) and growth appeared to be unaffected by perchlorate. Inhibition of development started with 2.2 ppm perchlorate and little or no development occurred at 22.9 ppm and above. This inhibition was particularly apparent at the latter stages of development including hindlimb formation and metamorphosis. The estimated EC50 for total inhibition of metamorphosis at 70 days of treatment was 3.63 ppm. There was no evidence of inhibition of development with the 50 + I, C + I, or controls, indicating that the presence of small concentrations of iodide could counter the effects of perchlorate. When tadpoles that had been inhibited by perchlorate were subsequently treated with iodide, development through prometamorphosis progressed but mortality was very high.

Perchlorate in the Hydrologic Cycle - An Overview of Sources and Occurrence

NASA Astrophysics Data System (ADS)

Stonestrom, D. A.; Jackson, W.; Mayer, K.; Orris, G. J.

2007-12-01

Perchlorate (ClO4-) in water and food is of concern due to deleterious health affects associated with hypothyroidism. The presence of widespread perchlorate in 0-to-28 ka-old pristine ground water of the Middle Rio Grande Basin (Plummer et al., 2006, ES&T, DOI:10.1021/es051739h), in ground water >1 mile from agricultural activities in the Southern High Plains (Rajagapolan et al., 2006, ES&T, DOI:10.1021/es052155i), and in unsaturated zones throughout the arid and semiarid southwestern United States (Rao et al., 2007, ES&T, DOI:10.1021/es062853i) clearly indicates that perchlorate is a non-exotic component of the hydrologic cycle, at least in dry environments. The natural system has been greatly perturbed in places by human activities. Most anthropogenic inputs are associated with the manufacture and use of explosives and rocket fuel, providing concentrated sources of excess perchlorate to the hydrologic cycle. Perchlorate-containing fertilizers and irrigation provide dispersed sources within and down-gradient from agricultural areas. Natural sources include photochemically mediated reactions involving ozone at the land surface and in the lower atmosphere. A growing body of work indicates that a small, but persistent, meteoric source acting over thousands of years can explain observed accumulations of unsaturated-zone perchlorate in arid regions. In addition to meteoric sources, oxyanions produced during volcanogenic processes can include appreciable amounts of natural perchlorate. Terrestrial plants take up perchlorate in soil water, with some species of xerophytic succulents concentrating the anion to high levels. Similarly, perchlorate in marine plants indicates that perchlorate is part of marine biochemical cycles. Perchlorate-bearing marine sediments of late Tertiary age suggest that perchlorate has been part of global geochemical cycles for millions of years and, furthermore, can be preserved in the subsurface despite the nearly ubiquitous presence of

PERCHLORATE INDUCES HERMAPHRODITISM IN THREESPINE STICKLEBACKS

PubMed Central

Bernhardt, Richard R.; von Hippel, Frank A.; Cresko, William A.

2011-01-01

Recently, concern regarding perchlorate contamination has arisen in many contexts. Perchlorate has many military, commercial, and domestic applications, and it has been found in milk, drinking and irrigation water, and produce. Perchlorate is harmful at low levels, yet it remains unregulated in the United States while the U.S. Environmental Protection Agency attempts to establish acceptable exposure levels. The present study investigated potential reproductive effects on vertebrates using a model fish species, the threespine stickleback (Gasterosteus aculeatus). Sticklebacks were raised from syngamy through sexual maturity in untreated water and in three target concentrations of sodium perchlorate–treated water. Perchlorate was found to interfere with the expression of nuptial coloration, courtship behavior, and normal sexual development. Genetic testing revealed that some females were masculinized to the extent that they produced both sperm and eggs, and histological analysis showed that these individuals had intersexual gonads (ovotestes) containing both oocytes and cells undergoing spermatogenesis. In vitro fertilizations revealed that those gametes were capable of self- and cross-fertilization. However, crosses using sperm derived from genetic females died either during the blastula phase or near the onset of organogenesis. Sperm derived from genetic males produced viable fry when crossed with eggs derived from genetic females from all treatments. To our knowledge, the present study provides the first evidence that perchlorate produces androgenic effects and is capable of inducing functional hermaphroditism in a nonhermaphroditic vertebrate. PMID:16916028

PERCHLORATE IN FERTILIZERS?: ANALYSIS BY RAMAN SPECTROSCOPY

EPA Science Inventory

Recently, we and others found perchlorate at high levels (approximately 500 - 8000 mg/kg) in 90+% of 25+ fertilizers (primarily lawn-and-garden products) that are not identified as containing components derived from mined Chile saltpeter, which is known to contain perchlorate as ...

MARGINAL IODINE DEFICIENCY EXACERBATES PERCHLORATE THYROID TOXICITY.

EPA Science Inventory

The environmental contaminant perchlorate disrupts thyroid homeostasis via inhibition of iodine uptake into the thyroid. This work tested whether iodine deficiency exacerbates the effects of perchlorate. Female 27 day-old LE rats were fed a custom iodine deficient diet with 0, 50...

PERCHLORATE ACCUMULATION FROM FERTILIZER IN LEAFY VEGETATION

EPA Science Inventory

Perchlorate contaminated water and soil has been identified in many areas of the United States. Previous studies indicated that the primary source of contamination was from industry and military operations that use perchlorate as an oxidzing agent. However, recent studies have fo...

Perchlorate exposure in lactating women in an urban community in New Jersey.

PubMed

Borjan, Marija; Marcella, Stephen; Blount, Benjamin; Greenberg, Michael; Zhang, Junfeng Jim; Murphy, Eileen; Valentin-Blasini, Liza; Robson, Mark

2011-01-01

Perchlorate is most widely known as a solid oxidant for missile and rocket propulsion systems although it is also present as a trace contaminant in some fertilizers. It has been detected in drinking water, fruits, and vegetables throughout New Jersey and most of the United States. At sufficiently high doses, perchlorate interferes with the uptake of iodine into the thyroid and may interfere with the development of the skeletal system and the central nervous system of infants. Therefore, it is important to quantify perchlorate in breast milk to understand potential perchlorate exposure in infants. In this study we measured perchlorate in breast milk, urine, and drinking water collected from 106 lactating mothers from Central New Jersey. Each subject was asked to provide three sets of samples over a 3-month period. The average±SD perchlorate level in drinking water, breast milk, and urine was 0.168±0.132 ng/mL (n=253), 6.80±8.76 ng/mL (n=276), and 3.19±3.64 ng/mL (3.51±6.79 μg/g creatinine) (n=273), respectively. Urinary perchlorate levels were lower than reference range values for women of reproductive age (5.16±11.33 μg/g creatinine, p=0.03), likely because of perchlorate secretion in breast milk. Drinking water perchlorate levels were ≤1.05 ng/mL and were not positively correlated with either breast milk or urine perchlorate levels. These findings together suggest that drinking water was not the most important perchlorate exposure source for these women. Creatinine-adjusted urine perchlorate levels were strongly correlated with breast milk perchlorate levels (r=0.626, p=<0.0005). Breast milk perchlorate levels in this study are consistent with widespread perchlorate exposure in lactating women and thus infants. This suggests that breast milk may be a source of exposure to perchlorate in infants. Copyright © 2010 Elsevier B.V. All rights reserved.

Cationic metal complex, carbonatobis(1,10-phenanthroline)cobalt(III) as anion receptor: Synthesis, characterization, single crystal X-ray structure and packing analysis of [Co(phen) 2CO 3](3,5-dinitrobenzoate)·5H 2O

NASA Astrophysics Data System (ADS)

Sharma, Raj Pal; Singh, Ajnesh; Brandão, Paula; Felix, Vitor; Venugopalan, Paloth

2009-03-01

To explore the potential of [Co(phen) 2CO 3] + as anion receptor, red coloured single crystals of [Co(phen) 2CO 3](dnb)·5H 2O (dnb = 3,5-dinitrobenzoate) were obtained by recrystallizing the red microcrystalline product synthesised by the reaction of carbonatobis (1,10-phenanthroline)cobalt(III)chloride with sodium salt of 3,5-dinitrobenzoic acid in aqueous medium (1:1 molar ratio). The newly synthesized complex salt has been characterized by elemental analysis, spectroscopic studies (IR, UV/visible, 1H and 13C NMR), solubility and conductance measurements. The complex salt crystallizes in the triclinic crystal system with space group P1¯, having the cell dimensions a = 10.3140(8), b = 12.2885(11), c = 12.8747(13), α = 82.095(4), β = 85.617(4), γ = 79.221(4)°, V = 1585.6(2) Å 3, Z = 2. Single crystal X-ray structure determination revealed ionic structure consisting of cationic carbonatobis(1,10-phenanthroline)cobalt(III), dnb anion and five lattice water molecule. In the complex cation [Co(phen) 2CO 3] +, the cobalt(III) is bonded to four nitrogen atoms, originating from two phenanthroline ligands and two oxygen atoms from the bidentate carbonato group showing an octahedral geometry around cobalt(III) center. Supramolecular networks between ionic groups [ CHphen+⋯Xanion-] by second sphere coordination i.e. C sbnd H⋯O (benzoate), C sbnd H⋯O (nitro), C sbnd H⋯O (water) besides electrostatic forces of attraction alongwith π-π interactions stabilize the crystal lattice.

CHRONIC PERCHLORATE EXPOSURE CAUSES MORPHOLOGICAL ABNORMALITIES IN DEVELOPING STICKLEBACK

PubMed Central

Bernhardt, Richard R.; Von Hippel, Frank A.; O’Hara, Todd M.

2011-01-01

Few studies have examined the effects of chronic perchlorate exposure during growth and development, and fewer still have analyzed the effects of perchlorate over multiple generations. We describe morphological and developmental characteristics for threespine stickleback (Gasterosteus aculeatus) that were spawned and raised to sexual maturity in perchlorate-treated water (G1,2003) and for their offspring (G2,2004) that were not directly treated with perchlorate. The G1,2003 displayed a variety of abnormalities, including impaired formation of calcified traits, slower growth rates, aberrant sexual development, poor survivorship, and reduced pigmentation that allowed internal organs to be visible. Yet these conditions were absent when the offspring of contaminated fish (G2,2004) were raised in untreated water, suggesting a lack of transgenerational effects and that surviving populations may be able to recover following remediation of perchlorate-contaminated sites PMID:21465539

Development of an extraction method for perchlorate in soils.

PubMed

Cañas, Jaclyn E; Patel, Rashila; Tian, Kang; Anderson, Todd A

2006-03-01

Perchlorate originates as a contaminant in the environment from its use in solid rocket fuels and munitions. The current US EPA methods for perchlorate determination via ion chromatography using conductivity detection do not include recommendations for the extraction of perchlorate from soil. This study evaluated and identified appropriate conditions for the extraction of perchlorate from clay loam, loamy sand, and sandy soils. Based on the results of this evaluation, soils should be extracted in a dry, ground (mortar and pestle) state with Milli-Q water in a 1 ratio 1 soil ratio water ratio and diluted no more than 5-fold before analysis. When sandy soils were extracted in this manner, the calculated method detection limit was 3.5 microg kg(-1). The findings of this study have aided in the establishment of a standardized extraction method for perchlorate in soil.

Project Overview: PERCHLORATE ENVIRONMENTAL CONTAMINATION - TOXICOLOGICAL REVIEW AND RISK CHARACTERIZATION

EPA Science Inventory

The human health and ecological assessment issues related to environmental contamination by perchlorate are complex and continue to emerge. Perchlorate, ClO4-, is an anion that originates as a contaminant from the solid salts of ammonium, potassium or sodium perchlorate. These ...

PERCHLORATE-CROP INTERACTIONS FROM CONTAMINATED IRRIGATION WATER AND FERTILIZER APPLICATIONS

EPA Science Inventory

Perchlorate has contaminated water and soils at several locations in the United States. Perchlorate is water soluble, exceedingly mobile in aqueous systems, and can persist for many decades under typical ground and surface water conditions. Perchlorate is of concern because of un...

Cobalt

USGS Publications Warehouse

Slack, John F.; Kimball, Bryn E.; Shedd, Kim B.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

Cobalt is a silvery gray metal that has diverse uses based on certain key properties, including ferromagnetism, hardness and wear-resistance when alloyed with other metals, low thermal and electrical conductivity, high melting point, multiple valences, and production of intense blue colors when combined with silica. Cobalt is used mostly in cathodes in rechargeable batteries and in superalloys for turbine engines in jet aircraft. Annual global cobalt consumption was approximately 75,000 metric tons in 2011; China, Japan, and the United States (in order of consumption amount) were the top three cobalt-consuming countries. In 2011, approximately 109,000 metric tons of recoverable cobalt was produced in ores, concentrates, and intermediate products from cobalt, copper, nickel, platinum-group-element (PGE), and zinc operations. The Democratic Republic of the Congo (Congo [Kinshasa]) was the principal source of mined cobalt globally (55 percent). The United States produced a negligible amount of byproduct cobalt as an intermediate product from a PGE mining and refining operation in southeastern Montana; no U.S. production was from mines in which cobalt was the principal commodity. China was the leading refiner of cobalt, and much of its production came from cobalt ores, concentrates, and partially refined materials imported from Congo (Kinshasa).The mineralogy of cobalt deposits is diverse and includes both primary (hypogene) and secondary (supergene) phases. Principal terrestrial (land-based) deposit types, which represent most of world’s cobalt mine production, include primary magmatic Ni-Cu(-Co-PGE) sulfides, primary and secondary stratiform sediment-hosted Cu-Co sulfides and oxides, and secondary Ni-Co laterites. Seven additional terrestrial deposit types are described in this chapter. The total terrestrial cobalt resource (reserves plus other resources) plus past production, where available, is calculated to be 25.5 million metric tons. Additional resources of

Aquifer susceptibility to perchlorate contamination in a highly urbanized environment

USGS Publications Warehouse

Woolfenden, Linda R.; Trefly, Michael G.

2007-01-01

Perchlorate contamination from anthropogenic sources has been released into the Rialto-Colton, California, USA, groundwater flow system since the 1940s during its production, distribution, storage, and use. Preliminary analysis of lithological, geophysical, and water-chemistry data provided new understanding of the pathways of perchlorate migration that aid in assessing the susceptibility of drinking-water supplies to contamination within the Rialto-Colton basin. Vertical migration of perchlorate into the main water-producing aquifers is restricted by an areally extensive old soil surface; however, perchlorate data indicate contamination below this soil surface. Possible pathways for the downward migration of the contaminated water include wellbore flow and discontinuities in the old soil surface. Horizontal migration of perchlorate is influenced by lithology and faults within the basin. The basin fill is a heterogeneous mixture of boulders, gravel, sand, silt, and clay, and internal faults may restrict perchlorate migration in some areas.

Perchlorate in fish from a contaminated site in east-central Texas.

PubMed

Theodorakis, Christopher; Rinchard, Jacques; Anderson, Todd; Liu, Fujun; Park, June-Woo; Costa, Filipe; McDaniel, Leslie; Kendall, Ronald; Waters, Aaron

2006-01-01

Perchlorate, a known thyroid endocrine disruptor, contaminates surface waters near military instillations where solid fuel rocket motors are manufactured or assembled. To assess potential perchlorate exposure to fish and the human population which may feed on them, fish were collected around the Naval Weapons Industrial Reserve Plant in McLennan County, TX, and analyzed for the presence of the perchlorate anion. The sampling sites included Lake Waco and Belton Lake, and several streams and rivers within their watersheds. The general tendency was that perchlorate was only found in a few species sampled, and perchlorate was not detected in every individual within these species. When detected in the fish, perchlorate tissue concentrations were greater than that in the water. This may be due to highly variable perchlorate concentrations in the water coupled with individual-level variation in elimination from the body, or to routes of exposure other than water.

Basis of the Massachusetts reference dose and drinking water standard for perchlorate.

PubMed

Zewdie, Tsedash; Smith, C Mark; Hutcheson, Michael; West, Carol Rowan

2010-01-01

Perchlorate inhibits the uptake of iodide in the thyroid. Iodide is required to synthesize hormones critical to fetal and neonatal development. Many water supplies and foods are contaminated with perchlorate. Exposure standards are needed but controversial. Here we summarize the basis of the Massachusetts (MA) perchlorate reference dose (RfD) and drinking water standard (DWS), which are considerably lower and more health protective than related values derived by several other agencies. We also review information regarding perchlorate risk assessment and policy. MA Department of Environmental Protection (DEP) scientists, with input from a science advisory committee, assessed a wide range of perchlorate risk and exposure information. Health outcomes associated with iodine insufficiency were considered, as were data on perchlorate in drinking water disinfectants. We used a weight-of-the-evidence approach to evaluate perchlorate risks, paying particular attention to sensitive life stages. A health protective RfD (0.07 microg/kg/day) was derived using an uncertainty factor approach with perchlorate-induced iodide uptake inhibition as the point of departure. The MA DWS (2 microg/L) was based on risk management decisions weighing information on perchlorate health risks and its presence in certain disinfectant solutions used to treat drinking water for pathogens. Current data indicate that perchlorate exposures attributable to drinking water in individuals at sensitive life stages should be minimized and support the MA DEP perchlorate RfD and DWS. Widespread exposure to perchlorate and other thyroid toxicants in drinking water and foods suggests that more comprehensive policies to reduce overall exposures and enhance iodine nutrition are needed.

Perchlorate and halophilic prokaryotes: implications for possible halophilic life on Mars.

PubMed

Oren, Aharon; Elevi Bardavid, Rahel; Mana, Lily

2014-01-01

In view of the finding of perchlorate among the salts detected by the Phoenix Lander on Mars, we investigated the relationships of halophilic heterotrophic microorganisms (archaea of the family Halobacteriaceae and the bacterium Halomonas elongata) toward perchlorate. All strains tested grew well in NaCl-based media containing 0.4 M perchlorate, but at the highest perchlorate concentrations, tested cells were swollen or distorted. Some species (Haloferax mediterranei, Haloferax denitrificans, Haloferax gibbonsii, Haloarcula marismortui, Haloarcula vallismortis) could use perchlorate as an electron acceptor for anaerobic growth. Although perchlorate is highly oxidizing, its presence at a concentration of 0.2 M for up to 2 weeks did not negatively affect the ability of a yeast extract-based medium to support growth of the archaeon Halobacterium salinarum. These findings show that presence of perchlorate among the salts on Mars does not preclude the possibility of halophilic life. If indeed the liquid brines that may exist on Mars are inhabited by salt-requiring or salt-tolerant microorganisms similar to the halophiles on Earth, presence of perchlorate may even be stimulatory when it can serve as an electron acceptor for respiratory activity in the anaerobic Martian environment.

Perchlorate reduction by autotrophic bacteria in the presence of zero-valent iron.

PubMed

Yu, Xueyuan; Amrhein, Christopher; Deshusses, Marc A; Matsumoto, Mark R

2006-02-15

A series of batch experiments were performed to study the combination of zero-valent iron (ZVI) with perchlorate-reducing microorganisms (PRMs) to remove perchlorate from groundwater. In this method, H2 produced during the process of iron corrosion by water is used by PRMs as an electron donor to reduce perchlorate to chloride. Perchlorate degradation rates followed Monod kinetics, with a normalized maximum utilization rate (rmax) of 9200 microg g(-1) (dry wt) h(-1) and a half-velocity constant (Ks) of 8900 microg L(-1). The overall rate of perchlorate reduction was affected by the biomass density within the system. An increase in the OD600 from 0.025 to 0.08 led to a corresponding 4-fold increase of perchlorate reduction rate. PRM adaptation to the local environment and initiation of perchlorate reduction was rapid under neutral pH conditions. At the initial OD600 of 0.015, perchlorate reduction followed pseudo-first-order reaction rates with constants of 0.059 and 0.033 h(-1) at initial pH 7 and 8, respectively. Once perchlorate reduction was established, the bioreductive process was insensitive to the increases of pH from near neutral to 9.0. In the presence of nitrate, perchlorate reduction rate was reduced, but not inhibited completely.

Effects of Perchlorate on Organic Molecules under Simulated Mars Conditions

NASA Astrophysics Data System (ADS)

Carrier, B. L.; Kounaves, S. P.

2014-12-01

Perchlorate (ClO4-) was discovered in the northern polar region of Mars by the Mars Phoenix Lander in 2008 and has also been recently detected by the Curiosity Rover in Gale Crater [1,2]. Perchlorate has also been shown to be formed under current Mars conditions via the oxidation of mineral chlorides, further supporting the theory that perchlorate is present globally on Mars [3]. The discovery of perchlorate on Mars has raised important questions about the effects of perchlorate on the survival and detection of organic molecules. Although it has been shown that pyrolysis in the presence of perchlorate results in the alteration or destruction of organic molecules [4], few studies have been conducted on the potential effects of perchlorate on organic molecules under martian surface conditions. Although perchlorate is typically inert under Mars-typical temperatures [5], perchlorate does absorb high energy UV radiation, and has been shown to decompose to form reactive oxychlorine species such as chlorite (ClO2-) when exposed to martian conditions including UV or ionizing radiation [6,7]. Here we investigate the effects of perchlorate on the organic molecules tryptophan, benzoic acid and mellitic acid in order to determine how perchlorate may alter these compounds under Mars conditions. Experiments are performed in a Mars Simulation Chamber (MSC) capable of reproducing the temperature, pressure, atmospheric composition and UV flux found on Mars. Soil simulants are prepared consisting of SiO2 and each organic, as well as varying concentrations of perchlorate salts, and exposed in the MSC. Subsequent to exposure in the MSC samples are leached and the leachate analyzed by HPLC and LC-MS to determine the degree of degradation of the original organic and the identity of any potential decomposition products formed by oxidation or chlorination. References: [1] Kounaves et al., J. Geophys. Res. Planets, Vol. 115, p. E00E10, 2010 [2] Glavin et al., J. Geophys. Res. Planets, Vol

Characteristics of electron transport chain and affecting factors for thiosulfate-driven perchlorate reduction.

PubMed

Zhang, Chao; Guo, Jianbo; Lian, Jing; Lu, Caicai; Ngo, Huu Hao; Guo, Wenshan; Song, Yuanyuan; Guo, Yankai

2017-10-01

The mechanism for perchlorate reduction was investigated using thiosulfate-driven (T-driven) perchlorate reduction bacteria. The influences of various environmental conditions on perchlorate reduction, including pH, temperature and electron acceptors were examined. The maximum perchlorate removal rate was observed at pH 7.5 and 40 °C. Perchlorate reduction was delayed due to the coexistence of perchlorate-chlorate and perchlorate-nitrate. The mechanism of the T-driven perchlorate reduction electron transport chain (ETC) was also investigated by utilizing different inhibitors. The results were as follows: firstly, the NADH dehydrogenase was not involved in the ETC; secondly, the FAD dehydrogenase and quinone loop participated in the ETC; and thirdly, cytochrome oxidase was the main pathway in the ETC. Meanwhile, microbial consortium structure analysis indicated that Sulfurovum which can oxidize sulfur compounds coupled to the reduction of nitrate or perchlorate was the primary bacterium in the T-driven and sulfur-driven consortium. This study generates a better understanding of the mechanism of T-driven perchlorate reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

ACCUMULATION AND FATE OF PERCHLORATE IN PLANTS

EPA Science Inventory

Perchlorate, a component of solid rocket fuels, has emerged as a potential threat to surface water and groundwater at several locations in the U.S. Perchlorate levels up to 16 ug/L were detected in Lake Mead and 5-9 ug/L in the lower Colorado River. The water from the Colorado Ri...

Basis of the Massachusetts Reference Dose and Drinking Water Standard for Perchlorate

PubMed Central

Zewdie, Tsedash; Smith, C. Mark; Hutcheson, Michael; West, Carol Rowan

2010-01-01

Objective Perchlorate inhibits the uptake of iodide in the thyroid. Iodide is required to synthesize hormones critical to fetal and neonatal development. Many water supplies and foods are contaminated with perchlorate. Exposure standards are needed but controversial. Here we summarize the basis of the Massachusetts (MA) perchlorate reference dose (RfD) and drinking water standard (DWS), which are considerably lower and more health protective than related values derived by several other agencies. We also review information regarding perchlorate risk assessment and policy. Data sources MA Department of Environmental Protection (DEP) scientists, with input from a science advisory committee, assessed a wide range of perchlorate risk and exposure information. Health outcomes associated with iodine insufficiency were considered, as were data on perchlorate in drinking water disinfectants. Data synthesis We used a weight-of-the-evidence approach to evaluate perchlorate risks, paying particular attention to sensitive life stages. A health protective RfD (0.07 μg/kg/day) was derived using an uncertainty factor approach with perchlorate-induced iodide uptake inhibition as the point of departure. The MA DWS (2 μg/L) was based on risk management decisions weighing information on perchlorate health risks and its presence in certain disinfectant solutions used to treat drinking water for pathogens. Conclusions Current data indicate that perchlorate exposures attributable to drinking water in individuals at sensitive life stages should be minimized and support the MA DEP perchlorate RfD and DWS. Widespread exposure to perchlorate and other thyroid toxicants in drinking water and foods suggests that more comprehensive policies to reduce overall exposures and enhance iodine nutrition are needed. PMID:20056583

Dealing With Perchlorate in the Santa Clarita Valley, CA

NASA Astrophysics Data System (ADS)

Boulos, L.; Min, J.; Juby, G.; McLean, S.; Prasifka, D.; Brown, J.

2004-05-01

Castaic Lake Water Agency was faced with a dilemma: how to support the increasing water needs of a growing population in the Santa Clarita Valley with three to five wells in the area shut-down due to the presence of perchlorate. Carollo Engineers was hired to design a treatment program for the removal of perchlorate from Saugus Aquifer. Several unknowns challenged the project including an uncertainty in a regulatory MCL for perchlorate, lack of brine line in the area, and low chloride limits in LACSD sewer lines. The preliminary phase of the project was to identify and recommend perchlorate treatment processes for further bench and/or pilot-scale testing. Two alternatives were selected: 1) Three NSF certified perchlorate-selective ion exchange resins and 2) Two types of biological treatment systems. Selection criteria included: cost, minimal formation of wastes and full-scale demonstration of the processes. This paper will focus on the basis, design, and findings from three perchlorate-selective ion-exchange resins. Bench-scale testing of the ion-exchange resins was conducted over a period of 3 months. NDMA formation following chlorination and chloramination was investigated. The spent resins were further characterized for metals and uranium. Results: Adsorption cycles of two of the resins lasted more than 70,000 bed volumes before perchlorate was detected in the effluent of the columns (approximately 200,000- 550,000 gal/cu-ft resin). No NDMA was formed as a result of post-chlorination with free and combined chlorine, or as a result of prechlorination with free chlorine. The metals measured in the spent results were well below the TTLC and STLC limits, despite the long run times. Ion-exchange is therefore a feasible technology for treatment perchlorate in the Santa Clarita Valley.

Potential mechanisms for bioregeneration of perchlorate-containing ion-exchange resin.

PubMed

Sharbatmaleki, Mohamadali; Unz, Richard F; Batista, Jacimaria R

2015-05-15

Ion-exchange (IX) is the most feasible technology for perchlorate removal from drinking water. Reuse of resins present challenges, however. Selective resins are non-regenerable, and are incinerated after one time use, while non-selective resins, when regenerable, produce a waste stream that contains high concentration of perchlorate that must be disposed of. A process to bioregenerate spent resin containing perchlorate with perchlorate-reducing bacteria (PRB) has been recently developed. In this research, potential mechanisms for bioregeneration of resin-attached perchlorate (RAP) were investigated. Batch bioregeneration experiments were performed using gel-type and macroporous-type resins. Various initial chloride concentrations and various resin bead sizes were used. The results of the bioregeneration experiments suggested that chloride, i.e. the product of perchlorate biodegradation, is more likely the desorbing agent of RAP; and increasing the concentration of chloride enhances the bioregeneration process. Both film and pore diffusion were found to be relevant with respect to the rate of perchlorate mass-transfer to the bulk liquid. Bioregeneration was found to be more effective for macroporous than for gel-type resins, especially in the case of macroporous resins with relatively small bead size in the presence of higher chloride concentration. Copyright © 2015 Elsevier Ltd. All rights reserved.

HAEM SYNTHASE AND COBALT PORPHYRIN SYNTHASE IN VARIOUS MICRO-ORGANISMS.

PubMed

PORRA, R J; ROSS, B D

1965-03-01

1. The preparation of a crude extract of Clostridium tetanomorphum containing cobalt porphyrin synthase but little haem-synthase activity is described. 2. The properties of cobalt porphyrin synthase in the clostridial extracts is compared with the properties of a haem synthase present in crude extracts of the yeast Torulopsis utilis. 3. Cobalt porphyrin synthase in extracts of C. tetanomorphum inserts Co(2+) ions into the following dicarboxylic porphyrins in descending order of rate of insertion: meso-, deutero- and proto-porphyrins. Esterification renders meso- and deutero-porphyrins inactive as substrates. Neither the tetracarboxylic (coproporphyrin III) nor the octacarboxylic (uroporphyrin III) compounds are converted into cobalt porphyrins by the extract, but the non-enzymic incorporation of Co(2+) ions into these two porphyrins is rapid. These extracts are unable to insert Mn(2+), Zn(2+), Mg(2+) or Cu(2+) ions into mesoporphyrin. 4. Crude extracts of T. utilis readily insert both Co(2+) and Fe(2+) ions into deutero-, meso, and proto-porphyrins. Unlike the extracts of C. tetanomorphum, these preparations catalyse the insertion of Co(2+) ions into deuteroporphyrin more rapidly than into mesoporphyrin. This parallels the formation of haems by the T. utilis extract. 5. Cobalt porphyrin synthase is present in the particulate fraction of the extracts of C. tetanomorphum but requires a heat-stable factor present in the soluble fraction. This soluble factor can be replaced by GSH. 6. Cobalt porphyrin synthase in the clostridial extract is inhibited by iodoacetamide and to a smaller extent by p-chloromercuribenzoate and N-ethylmaleimide. The haem synthases of T. utilis and Micrococcus denitrificans are also inhibited by various thiol reagents.

SURVEY OF FERTILIZERS AND RELATED MATERIALS FOR PERCHLORATE

EPA Science Inventory

The most comprehensive survey of fertilizers and other raw materials for perchlorate to date has been conducted to determine whether these could be significant contributors to environmental perchlorate contamination. Although the data span a large range of commercial products, th...

Direct Measurement of Perchlorate Exposure Biomarkers in a Highly Exposed Population: A Pilot Study

PubMed Central

Wong, Michelle; Copan, Lori; Olmedo, Luis; Patton, Sharyle; Haas, Robert; Atencio, Ryan; Xu, Juhua; Valentin-Blasini, Liza

2011-01-01

Exposure to perchlorate is ubiquitous in the United States and has been found to be widespread in food and drinking water. People living in the lower Colorado River region may have perchlorate exposure because of perchlorate in ground water and locally-grown produce. Relatively high doses of perchlorate can inhibit iodine uptake and impair thyroid function, and thus could impair neurological development in utero. We examined human exposures to perchlorate in the Imperial Valley among individuals consuming locally grown produce and compared perchlorate exposure doses to state and federal reference doses. We collected 24-hour urine specimen from a convenience sample of 31 individuals and measured urinary excretion rates of perchlorate, thiocyanate, nitrate, and iodide. In addition, drinking water and local produce were also sampled for perchlorate. All but two of the water samples tested negative for perchlorate. Perchlorate levels in 79 produce samples ranged from non-detect to 1816 ppb. Estimated perchlorate doses ranged from 0.02 to 0.51 µg/kg of body weight/day. Perchlorate dose increased with the number of servings of dairy products consumed and with estimated perchlorate levels in produce consumed. The geometric mean perchlorate dose was 70% higher than for the NHANES reference population. Our sample of 31 Imperial Valley residents had higher perchlorate dose levels compared with national reference ranges. Although none of our exposure estimates exceeded the U. S. EPA reference dose, three participants exceeded the acceptable daily dose as defined by bench mark dose methods used by the California Office of Environmental Health Hazard Assessment. PMID:21394205

Sensitivity and adaptability of methanogens to perchlorates: Implications for life on Mars

NASA Astrophysics Data System (ADS)

Kral, Timothy A.; Goodhart, Timothy H.; Harpool, Joshua D.; Hearnsberger, Christopher E.; McCracken, Graham L.; McSpadden, Stanley W.

2016-01-01

In 2008, the Mars Phoenix Lander discovered perchlorate at its landing site, and in 2012, the Curiosity rover confirmed the presence of perchlorate on Mars. The research reported here was designed to determine if certain methanogens could grow in the presence of three different perchlorate salt solutions. The methanogens tested were Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum and Methanococcus maripaludis. Media were prepared containing 0%, 0.5%, 1.0%, 2%, 5% and 10% wt/vol magnesium perchlorate, sodium perchlorate, or calcium perchlorate. Organisms were inoculated into their respective media followed by incubation at each organism's growth temperature. Methane production, commonly used to measure methanogen growth, was measured by gas chromatography of headspace gas samples. Methane concentrations varied with species and perchlorate salt tested. However, all four methanogens produced substantial levels of methane in the presence of up to 1.0% perchlorate, but not higher. The standard procedure for growing methanogens typically includes sodium sulfide, a reducing agent, to reduce residual molecular oxygen. However, the sodium sulfide may have been reducing the perchlorate, thus allowing for growth of the methanogens. To investigate this possibility, experiments were conducted where stainless steel nails were used instead of sodium sulfide as the reducing agent. Prior to the addition of perchlorate and inoculation, the nails were removed from the liquid medium. Just as in the prior experiments, the methanogens produced methane at comparable levels to those seen with sodium sulfide as the reductant, indicating that sodium sulfide did not reduce the perchlorate to any significant extent. Additionally, cells metabolizing in 1% perchlorate were transferred to 2%, cells metabolizing in 2% were transferred to 5%, and finally cells metabolizing in 5% were transferred to 10%. All four species produced methane at 2% and 5%, but not 10

Biodegradation of rocket propellant waste, ammonium perchlorate

NASA Technical Reports Server (NTRS)

Naqvi, S. M. Z.; Latif, A.

1975-01-01

The short term effects of ammonium perchlorate on selected organisms were studied. A long term experiment was also designed to assess the changes incurred by ammonium perchlorate on the nitrogen and chloride contents of soil within a period of 3 years. In addition, an attempt was made to produce methane gas from anaerobic fermentation of the aquatic weed, Alternanthera philoxeroides.

Perchlorate Questions and Answers

MedlinePlus

... decision making on perchlorate under the Safe Drinking Water Act. Scientists from the EPA and the FDA’s National Center for Toxicological Research (NCTR) collaborated to develop this modeling work, which ...

The Effects of Pulse Current Plating on the Mechanical Properties of Cobalt and Cobalt-Al2O3

DTIC Science & Technology

1977-04-01

258. Branson cobalt deposits as a function ol cu rrent pulses superImposed on Ultrasonic Corp.) was used tominimi,eAl ..0 agglomeration in a back...intens ify nucleation and growth processes leading to a Iheauthors wishtot hank Mr. Richard Carte rforprepar ingthe re finement in grain structure...i N BOX CM , I)UKE STATION ATTN : A~.1\\5T..SD ATTN : RI)Rl)- IP L 220 “III SIR E !~T N .E . Du RHAM , NC 27706 C1LARI U l’Tl Sv ILI.I. , VA 22901 Cl)R

Fatty acid profile in milk from goats, Capra aegagrus hircus, exposed to perchlorate and its relationship with perchlorate residues in human milk.

PubMed

Cheng, Qiuqiong; Smith, Ernest E; Kirk, Andrea B; Liu, Fujun; Boylan, Lee Mallory; McCarty, Michael E; Hart, Sybil; Dong, Linxia; Cobb, George P; Jackson, W Andrew; Anderson, Todd A

2007-10-01

Polyunsaturated fatty acids (PUFA) in milk are vital for normal growth and development of infant mammals. Changes in fatty acid composition were observed in milk fat from goats dosed with perchlorate (0.1 and 1 mg/kg body weight/day) for 31 days, but the effect was not persistent. Adaptation may be induced in these goats to compensate for the perchlorate effect. In an analysis of fatty acid composition in human milk samples, a weak negative correlation was observed between perchlorate concentrations and total PUFA in 38 human milk samples.

An Investigation into Palladium-Catalyzed Reduction of Perchlorate in Water

DTIC Science & Technology

2005-03-01

phytoremediation may help “naturally” reduce the spread of perchlorate in the environment. Rhizodegradation may be particularly effective for reducing...depth beyond the plant root zone, phytoremediation would be not affect the transport of perchlorate. Also, once perchlorate is dispersed in a large... Germany . At Spangdahlem, he led the Environmental Protection Element of the Bioenvironmental Engineering Flight and also led the 52nd Medical

Widespread natural perchlorate in unsaturated zones of the southwest United States

USGS Publications Warehouse

Rao, Balaji; Anderson, Todd A.; Orris, Greta J.; Rainwater, Ken A.; Rajagopalan, Srinath; Sandvig, Renee M.; Scanlon, Bridget R.; Stonestrom, David A.; Walvoord, Michelle Ann; Jackson, W Andrew

2007-01-01

A substantial reservoir (up to 1 kg ha-1) of natural perchlorate is present in diverse unsaturated zones of the arid and semi-arid southwestern United States. The perchlorate co-occurs with meteoric chloride that has accumulated in these soils throughout the Holocene [0 to 10−15 ka (thousand years ago)] and possibly longer periods. Previously, natural perchlorate widely believed to be limited to the Atacama Desert, now appears widespread in steppe-to-desert ecoregions. The perchlorate reservoir becomes sufficiently large to affect groundwater when recharge from irrigation or climate change flushes accumulated salts from the unsaturated zone. This new source may help explain increasing reports of perchlorate in dry region agricultural products and should be considered when evaluating overall source contributions.

Perchlorate as a Ground-Water Tracer Along the Lower Colorado River

NASA Astrophysics Data System (ADS)

Justet, L.; Lico, M. S.

2008-12-01

Anthropogenic perchlorate was first observed in the lower Colorado River (NV and AZ) in 1997. The perchlorate source was traced upstream from Hoover Dam and Lake Mead to Las Vegas Wash. Perchlorate migrated through the local surface- and ground-water systems to the Wash from nearby manufacturing facilities in Henderson, NV, which had been operating since the 1940s. The Nevada Division of Environmental Protection (NDEP) began monitoring perchlorate in the lower Colorado River at Willow Beach, located about 18 km south of the Dam, in 1997. A 3 μg/L reduction was observed at Willow Beach in 2003-2004, coincident with remediation at the Henderson site in 1999-2004. This observed decrease indicates that the effects of remediation rapidly propagated through the surface-water system below the Dam. In July 2008 water samples were collected and analyzed for perchlorate from eight springs along the lower Colorado River below Hoover Dam, from a discharge tunnel in the country rock at Hoover Dam, and from Lake Mead (above and below the thermocline). Lake Mead water collected above the thermocline east of Sentinel Island contained 3.9 μg/L perchlorate, while water below the thermocline contained 1.8 μg/L. Perchlorate concentrations were lower than the 2 to 4 μg/L quantitation limit for the six springs located more than 2 km south of the Dam. Samples from Pupfish Springs, about 0.9 km south of the Dam, contained 6.4-6.8 μg/L perchlorate. Water collected from the discharge tunnel in the Dam contained 8.2 μg/L perchlorate. Perchlorate concentrations observed at Pupfish Springs and the discharge tunnel in the Dam in 2008 are similar to those reported downstream at Willow Beach prior to 2003-2004 by NDEP indicating that the ground water travel time from the Dam to Pupfish Springs is between 4 and 70 years and the maximum flow velocities are between about 13-200 m/y. These rapid velocity estimates suggest that faults and fractures in the area are an important control on

Perchlorate Removal, Destruction and Field Monitoring Demonstration

DTIC Science & Technology

2007-03-01

perchlorate CSTR continuously stirred tank reactors DAB decyltrimethylammonium bromide DHS Department of Health Services DoD Department of Defense DWEL...reactors ( CSTR ) in series under anoxic conditions. A strong base anion resin was used to scavenge the concentrated spent regenerant solution as a super...evaluate perchlorate destruction in spent regenerant. The apparatus consisted of two 2.5-liter, continuously stirred tank reactors ( CSTR ) in

Electroremovable Traceless Hydrazides for Cobalt-Catalyzed Electro-Oxidative C-H/N-H Activation with Internal Alkynes.

PubMed

Mei, Ruhuai; Sauermann, Nicolas; Oliveira, João C A; Ackermann, Lutz

2018-06-27

Electrochemical oxidative C-H/N-H activations have been accomplished with a versatile cobalt catalyst in terms of [4 + 2] annulations of internal alkynes. The electro-oxidative C-H activation manifold proved viable with an undivided cell setup under exceedingly mild reaction conditions at room temperature using earth-abundant cobalt catalysts. The electrochemical cobalt catalysis prevents the use of transition metal oxidants in C-H activation catalysis, generating H 2 as the sole byproduct. Detailed mechanistic studies provided strong support for a facile C-H cobaltation by an initially formed cobalt(III) catalyst. The subsequent alkyne migratory insertion was interrogated by mass spectrometry and DFT calculations, providing strong support for a facile C-H activation and the formation of a key seven-membered cobalta(III) cycle in a regioselective fashion. Key to success for the unprecedented use of internal alkynes in electrochemical C-H/N-H activations was represented by the use of N-2-pyridylhydrazides, for which we developed a traceless electrocleavage strategy by electroreductive samarium catalysis at room temperature.

The Effects of Perchlorate on Methane Production of Methanogens

NASA Astrophysics Data System (ADS)

Goodhart, T.; Kral, T. A.

2010-04-01

In May 2008, the Phoenix space craft analyzed the martian soil, detecting perchlorate, which is a highly oxidizing compound and potentially harmful to organic matter. This presentation discusses the effects that perchlorate has on methanogen growth.

Cobalt.

PubMed

Fowler, Joseph F

2016-01-01

Cobalt has been a recognized allergen capable of causing contact dermatitis for decades. Why, therefore, has it been named 2016 "Allergen of the Year"? Simply put, new information has come to light in the last few years regarding potential sources of exposure to this metallic substance. In addition to reviewing some background on our previous understanding of cobalt exposures, this article will highlight the recently recognized need to consider leather as a major site of cobalt and the visual cues suggesting the presence of cobalt in jewelry. In addition, a chemical spot test for cobalt now allows us to better identify its presence in suspect materials.

Synthesis of hierarchical flower-like Co3O4 superstructure and its excellent catalytic property for ammonium perchlorate decomposition

NASA Astrophysics Data System (ADS)

Li, Gang; Bai, Weiyang

2018-04-01

Hierarchical flower-like cobalt tetroxide (Co3O4) was successfully synthesized via a facile precipitation method in combination with heat treatment of the cobalt oxalate precursor. The samples were systematically characterized by thermo gravimetric analysis and derivative thermo gravimetric analysis (TGA-DTG), X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and N2 adsorption-desorption measurements. The results indicate that the as-fabricated Co3O4 exhibits uniform flower-like morphologies with diameters of 8-12 μm, which are constructed by one-dimensional nanowires. Furthermore, catalytic effect of this hierarchical porous Co3O4 on ammonium perchlorate (AP) pyrolysis was investigated using differential scanning calorimetry (DSC) techniques. It is found that the pyrolysis temperature of AP shifts 142 °C downward with a 2 wt% addition content of Co3O4. Meanwhile, the addition of Co3O4 results in a dramatic reduction of the apparent activation energy of AP pyrolysis from 216 kJ mol-1 to 152 kJ mol-1, determined by the Kissinger correlation. The results endorse this material as a potential catalyst in AP decomposition.

Isolation and characterization of autotrophic, hydrogen-utilizing, perchlorate-reducing bacteria.

PubMed

Shrout, Joshua D; Scheetz, Todd E; Casavant, Thomas L; Parkin, Gene F

2005-04-01

Recent studies have shown that perchlorate (ClO(4) (-)) can be degraded by some pure-culture and mixed-culture bacteria with the addition of hydrogen. This paper describes the isolation of two hydrogen-utilizing perchlorate-degrading bacteria capable of using inorganic carbon for growth. These autotrophic bacteria are within the genus Dechloromonas and are the first Dechloromonas species that are microaerophilic and incapable of growth at atmospheric oxygen concentrations. Dechloromonas sp. JDS5 and Dechloromonas sp. JDS6 are the first perchlorate-degrading autotrophs isolated from a perchlorate-contaminated site. Measured hydrogen thresholds were higher than for other environmentally significant, hydrogen-utilizing, anaerobic bacteria (e.g., halorespirers). The chlorite dismutase activity of these bacteria was greater for autotrophically grown cells than for cells grown heterotrophically on lactate. These bacteria used fumarate as an alternate electron acceptor, which is the first report of growth on an organic electron acceptor by perchlorate-reducing bacteria.

Outcome Study of Cobalt Based Stereotactic Body Radiation Therapy for Patients with Inoperable Stage III Non-small Cell Lung Cancer.

PubMed

Wang, Yingjie; Lan, Fengming; Kang, Xiaoli; Shao, Yinjian; Li, Hongqi; Li, Ping; Wu, Weizhang; Wang, Jidong; Chang, Dongshu; Wang, Yong; Xia, Tingyi

2015-10-01

Aim of this paper is to retrospectively evaluate the efficacy and toxicity of specialized Body Cobalt based system (BCBS) treatment in the senior patients group (.65 years) with Stage III non-small cell lung carcinoma (NSCLC). A total of 49 patients (41 males and 8 females) with Stage III NSCLC according to UICC TNM classification (6(th) edition) were treated using OUR-QGD™ BCBS which was designed and manufactured in China. Post treatment evaluation with follow-up information was collected from April 2001 to December 2006 in our department. Median age of enrolled patients was 71 years old (65-85). Among those patients, 36 patients were pathologically identified with squamous cell carcinoma, and the other 13 patients were confirmed as adenocarcinoma. All patients were immobilized by vacuum based immobilization mold and then performed slow CT scan without any respiration gating devices. The daily radiation prescription dose was defined at 50% isodose line covering primary lesions and metastatic lymph nodes with doses from 2.5 to 6 Gy in 5 fractions per week according to the tumor stage and internally approved treatment protocols by the Institutional Review Board (IRB). Median daily dose and total delivery dose of 50% isodose line were 4 Gy and 41 Gy, respectively. In this study group, total of 3 patients received neoadjuvant cisplatin-based chemotherapy. Tumor response evaluated 12 weeks after radiation has demonstrated 13 complete responses (26.5%), 21 partial responses (42.9%). The overall survival (OS) rate of 1-year, 2-year and 3-year was 63.3%, 40.8% and 20.4%, respectively. The median and mean survival time was 22 and 24 months. All 49 patients tolerated the treatment well and have completed the planned therapy regiment. Body Cobalt based system treatment of those over 65 years old patients with Stage III NSCLC had reasonable and superior curative effect as well as local control, and at the same time without severe radiation side effects. © The Author

A bioassay for the detection of perchlorate in the ppb range.

PubMed

Heinnickel, Mark; Smith, Stephen C; Koo, Jonathan; O'Connor, Susan M; Coates, John D

2011-04-01

A bioassay for the determination of ppb (μg·L(-1)) concentrations of perchlorate has been developed and is described herein. The assay uses the enzyme perchlorate reductase (PR) from the perchlorate-reducing organism Dechloromonas agitata in purified and partially purified forms to detect perchlorate. The redox active dye phenazine methosulfate (PMS) is shown to efficiently shuttle electrons to PR from NADH. Perchlorate can be determined indirectly by monitoring NADH oxidization by PR. To lower the detection limit, we have shown that perchlorate can be concentrated on a solid-phase extraction (SPE) column that is pretreated with the cation decyltrimethylammonium bromide (DTAB). Perchlorate is eluted from these columns with a solution of 2 M NaCl and 200 mM morpholine propane sulfonic acid (MOPS, pH 12.5). By washing these columns with 15 mL of 2.5 mM DTAB and 15% acetone, contaminating ions, such as chlorate and nitrate, are removed without affecting the bioassay. Because of the effect of complex matrices on the SPE columns, the method of standard additions is used to analyze tap water and groundwater samples. The efficacy of the developed bioassay was demonstrated by analyzing samples from 2-17000 ppb in deionized lab water, tap water, and contaminated groundwater.

Bis(3,5-dimeth­oxy-2-{[2-(pyridin-2-yl)ethyl­imino-κN]­meth­yl}phenolato-κO)bis­(dimethyl sulfoxide)­manganese(III) perchlorate methanol 0.774-solvate

PubMed Central

Egekenze, Rita; Gultneh, Yilma

2017-01-01

The title compound, [Mn(C16H17N2O3)2(C2H6OS)2]ClO4·0.774CH3OH, comprises a central octa­hedrally coordinated MnIII cation, with two bidentate Schiff base ligands occupying the equatorial positions and two dimethyl sulfoxide (DMSO) ligands occupying the axial positions. There are two independant cations in the asymmetric unit, with the MnIII atoms of both cations being positioned on crystallographic centers of inversion. The perchlorate anion is disordered over two equivalent conformations, with occupancies of 0.744 (3) and 0.226 (3). In addition, there is a methanol solvent mol­ecule in the crystal lattice that is too close to the minor component of the perchlorate anion to be present simultaneously and thus it was refined to have the same occupancy as the major component of this anion. There is a Jahn–Teller distortion which results in Mn—ODMSO axial bond lengths of 2.2365 (12) and 2.2368 (12) Å in the two cations. In the crystal, inter­molecular π–π stacking between the non-coordinating pyridine rings of each cation is observed. This π–π stacking, along with extensive O—H⋯O hydrogen bonding and C—H⋯O inter­actions, link the components into a complex three-dimensional array. PMID:29250362

ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS: DEVELOPMENT OF A PLANT KINETIC MODEL

EPA Science Inventory

Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in plant tissues. This research determined the uptake, translocation, and accumulation of perchlorate in tobacco plants. Three hydroponics growth studies were completed u...

Synthesis, structures and urease inhibitory activity of cobalt(III) complexes with Schiff bases.

PubMed

Jing, Changling; Wang, Cunfang; Yan, Kai; Zhao, Kedong; Sheng, Guihua; Qu, Dan; Niu, Fang; Zhu, Hailiang; You, Zhonglu

2016-01-15

A series of new cobalt(III) complexes were prepared. They are [CoL(1)(py)3]·NO3 (1), [CoL(2)(bipy)(N3)]·CH3OH (2), [CoL(3)(HL(3))(N3)]·NO3 (3), and [CoL(4)(MeOH)(N3)] (4), where L(1), L(2), L(3) and L(4) are the deprotonated form of N'-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide, N'-(2-hydroxybenzylidene)-3-hydroxylbenzohydrazide, 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol, and N,N'-bis(5-methylsalicylidene)-o-phenylenediamine, respectively, py is pyridine, and bipy is 2,2'-bipyridine. The complexes were characterized by infrared and UV-Vis spectra, and single crystal X-ray diffraction. The Co atoms in the complexes are in octahedral coordination. Complexes 1 and 4 show effective urease inhibitory activities, with IC50 values of 4.27 and 0.35 μmol L(-1), respectively. Complex 2 has medium activity against urease, with IC50 value of 68.7 μmol L(-1). While complex 3 has no activity against urease. Molecular docking study of the complexes with Helicobacter pylori urease was performed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Uptake, elimination, and relative distribution of perchlorate in various tissues of channel catfish

USGS Publications Warehouse

Park, J.-W.; Bradford, C.M.; Rinchard, J.; Liu, F.; Wages, M.; Waters, A.; Kendall, R.J.; Anderson, T.A.; Theodorakis, C.W.

2007-01-01

This study was undertaken to determine the kinetics of uptake and elimination of perchlorate in channel catfish, Ictalurus punctatus. Perchlorate - an oxidizer used in solid fuel rockets, fireworks, and illuminating munitions - has been shown to effect thyroid function, causing hormone disruption and potential perturbations of metabolic activities. For the uptake study, catfish were exposed to 100 mg/L sodium perchlorate for 12 h to 5 d in the laboratory. Perchlorate in tissues was analyzed using ion chromatography. The highest perchlorate concentrations were found in the head and fillet, indicating that these tissues are the most important tissues to analyze when determining perchlorate uptake into large fish. To calculate uptake and elimination rate constants for fillet, gills, G-I tract, liver, and head, fish were exposed to 100 ppm sodium perchlorate for 5 days, and allowed to depurate in clean water for up to 20 days. The animals rapidly eliminated the perchlorate accumulated showing the highest elimination in fillet (Ke = 1.67 day -1) and lowest elimination in liver (Ke = 0.79 day -1). ?? 2007 American Chemical Society.

Chlorine isotopic composition of perchlorate in human urine as a means of distinguishing among exposure sources.

PubMed

Poghosyan, Armen; Morel-Espinosa, Maria; Valentin-Blasini, Liza; Blount, Benjamin C; Ferreccio, Catterina; Steinmaus, Craig M; Sturchio, Neil C

2016-01-01

Perchlorate (ClO4(-)) is a ubiquitous environmental contaminant with high human exposure potential. Natural perchlorate forms in the atmosphere from where it deposits onto the surface of Earth, whereas synthetic perchlorate is manufactured as an oxidant for industrial, aerospace, and military applications. Perchlorate exposure can potentially cause adverse health effects in humans by interfering with the production of thyroid hormones through competitively blocking iodide uptake. To control and reduce perchlorate exposure, the contributions of different sources of perchlorate exposure need to be quantified. Thus, we demonstrate a novel approach for determining the contribution of different perchlorate exposure sources by quantifying stable and radioactive chlorine isotopes of perchlorate extracted from composite urine samples from two distinct populations: one in Atlanta, USA and one in Taltal, Chile (Atacama region). Urinary perchlorate from the Atlanta region resembles indigenous natural perchlorate from the western USA (δ(37)Cl=+4.1±1.0‰; (36)Cl/Cl=1 811 (±136) × 10(-15)), and urinary perchlorate from the Taltal, Chile region is similar to natural perchlorate in nitrate salt deposits from the Atacama Desert of northern Chile (δ(37)Cl=-11.0±1.0‰; (36)Cl/Cl=254 (±40) × 10(-15)). Neither urinary perchlorate resembled the isotopic pattern found in synthetic perchlorate. These results indicate that natural perchlorate of regional provenance is the dominant exposure source for the two sample populations, and that chlorine isotope ratios provide a robust tool for elucidating perchlorate exposure pathways.

INVESTIGATION OF AGRICULTURAL FERTILIZERS AND RELATED MATERIALS FOR PERCHLORATE

EPA Science Inventory

The most comprehensive survey of fertilizers and other raw materials for perchlorate to date has been conducted to determine whether these could be significant contributors to environmental perchlorate contamination. Although the data span a large range of commercial products, th...

Construction of Pyrrolo[1,2-a]indoles via Cobalt(III)-Catalyzed Enaminylation of 1-(Pyrimidin-2-yl)-1H-indoles with Ketenimines and Subsequent Base-Promoted Cyclization.

PubMed

Zhou, Xiaorong; Fan, Zili; Zhang, Zhiyin; Lu, Ping; Wang, Yanguang

2016-09-16

A cobalt(III)-catalyzed cross-coupling reaction of 1-(pyrimidin-2-yl)-1H-indoles with ketenimines is reported. The reaction provided 2-enaminylated indole derivatives in moderate to excellent yields with a broad substrate scope. The prepared 2-enaminylated indoles could be conveniently converted into pyrrolo[1,2-a]indoles, which are an important class of compounds in medicinal chemistry.

Supercooling and Ice Formation of Perchlorate Brines under Mars-relevant Conditions

NASA Astrophysics Data System (ADS)

Primm, K.; Gough, R. V.; Tolbert, M. A.

2015-12-01

Perchlorate salts, discovered in the Martian regolith at multiple landing sites, may provide pathways for liquid water stability on current Mars. It has previously been assumed that if perchlorate brines form in the Martian regolith via melting or deliquescence, they would be present only briefly because efflorescence into a crystal or freezing to ice would soon occur. Here, we used a Raman microscope to study the temperature and relative humidity (RH) conditions at which magnesium perchlorate brine will form ice. Although ice is thermodynamically predicted to form whenever the saturation with respect to ice (Sice) is greater than or equal to 1, ice formation by perchlorate brines did not occur until elevated Sice values were reached: Sice= 1.17, 1.29, and 1.25 at temperatures of 218 K, 230.5 K, and 244 K, respectively. If a magnesium perchlorate particle was allowed to deliquesce completely prior to experiencing ice supersaturation, the extent of supercooling was increased even further. These high supersaturation values imply perchlorate brines can exist over a wider range of conditions than previously believed. From these experiments it has been found that magnesium perchlorate exhibits supercooling well into the previous theoretical ice region of the stability diagram and that liquid brines on Mars could potentially exist for up to two additional hours per sol. This supercooling of magnesium perchlorate will help with the exploration of Mars by the Mars 2020 spacecraft by helping to understand the phase and duration of water existing in the Martian subsurface.

Photooxidation of chloride by oxide minerals: implications for perchlorate on Mars.

PubMed

Schuttlefield, Jennifer D; Sambur, Justin B; Gelwicks, Melissa; Eggleston, Carrick M; Parkinson, B A

2011-11-09

We show that highly oxidizing valence band holes, produced by ultraviolet (UV) illumination of naturally occurring semiconducting minerals, are capable of oxidizing chloride ion to perchlorate in aqueous solutions at higher rates than other known natural perchlorate production processes. Our results support an alternative to atmospheric reactions leading to the formation of high concentrations of perchlorate on Mars.

Perchlorate Treatment Technology Update

EPA Pesticide Factsheets

This issue paper has been prepared by EPA's Federal Facilities Forum to provide information about technologies available for treatment of perchlorate contamination in environmental media, including technologies that have been used to date and others that..

Chronic perchlorate exposure impairs stickleback reproductive behaviour and swimming performance

PubMed Central

Bernhardt, Richard R.; von Hippel, Frank A.

2011-01-01

Summary We describe behavioural changes in two generations of threespine stickleback (Gasterosteus aculeatus) exposed to environmentally relevant concentrations of perchlorate. The first generation (G0,2002) was exposed as two-year-old adults to perchlorate in experimental groups ranging in concentration from less than the method detection limit (<1.1 ppb) to 18.6 ppm for up to 22 days during their courtship, spawning, egg guarding, and first five days of fry guarding. No differences were noted in the behaviour or reproductive output of these fish that were exposed as adults. However, perchlorate exposure throughout development caused widespread effects in the second generation (G1,2003), which was spawned and raised through sexual maturity in one of four nominal experimental groups (0, 30 and 100 ppm, and a ‘variable’ treatment that progressively increased from <1.1 ppb to approximately 60 ppm perchlorate). Dose-dependent effects were found during the G1,2003’s swimming and behavioural evaluations, including higher mortality rates among treated fish following stressful events. Perchlorate-exposed fish had higher failure rates during swimming trials and failed at lower flow rates than control fish. A number of treated fish exhibited seizures. Progressively fewer males completed benchmark metrics, such as nest building, spawning, nursery formation, or fry production, in a dose-dependent manner. Fewer males from higher treatments courted females, and those that did initiated courtship later and had a reduced behavioural repertoire compared to fish from lower treatments. The lowest observed adverse effect level (LOAEL) for swimming performance, reproductive behaviour, survivorship and recruitment was 30 ppm perchlorate (our lowest G1,2003 treatment), and near complete inhibition of reproductive activity was noted among males raised in 100 ppm perchlorate. A small number of treated G1,2003 females were isolated in aquaria, and some performed reproductive

An upper-bound assessment of the benefits of reducing perchlorate in drinking water.

PubMed

Lutter, Randall

2014-10-01

The Environmental Protection Agency plans to issue new federal regulations to limit drinking water concentrations of perchlorate, which occurs naturally and results from the combustion of rocket fuel. This article presents an upper-bound estimate of the potential benefits of alternative maximum contaminant levels for perchlorate in drinking water. The results suggest that the economic benefits of reducing perchlorate concentrations in drinking water are likely to be low, i.e., under $2.9 million per year nationally, for several reasons. First, the prevalence of detectable perchlorate in public drinking water systems is low. Second, the population especially sensitive to effects of perchlorate, pregnant women who are moderately iodide deficient, represents a minority of all pregnant women. Third, and perhaps most importantly, reducing exposure to perchlorate in drinking water is a relatively ineffective way of increasing iodide uptake, a crucial step linking perchlorate to health effects of concern. © 2014 Society for Risk Analysis.

Direct Fixed-Bed Biological Perchlorate Destruction Demonstration

DTIC Science & Technology

2009-04-01

emerging drinking regulations, which primarily apply to distributed water quality, utilities will also have to consider how to handle the backwash (BW...installation and operation of a potable, FXB biological perchlorate treatment system must be applied for and received from the California Department of Public...perchlorate in the raw water (e.g., ~1 mg/L)? This issue targets the question of whether the FXB bioreactor system can be applied at a remediation

PERCHLORATE IDENTIFICATION IN FERTILIZERS AND ACCUMULATION IN LETTUCE SEEDLINGS

EPA Science Inventory

Perchlorate has contaminated groundwater, drinking water and soils at several locations in the U.S. The primary source of contamination at sites that have been investigated to date seems to be from industrial and military operations that use Perchlorate as an oxidizing agent. How...

The Effect of Gamma Radiation on Mars Mineral Matrices: Implications for Perchlorate Formation on Mars

NASA Astrophysics Data System (ADS)

Fox, A. C.; Eigenbrode, J. L.; Pavlov, A.; Lewis, J.

2017-12-01

Observations by the Phoenix Wet Chemistry Lab of the Martian surface indicate the presence of perchlorate in high concentrations. Additional observations by the Sample Analysis at Mars and the Viking Landers indirectly support the presence of perchlorate at other localities on Mars. The evidence for perchlorate at several localities on Mars coupled with its detection in Martian meteorite EETA79001 suggests that perchlorate is present globally on Mars. The presence of perchlorate on Mars further complicates the search for organic molecules indicative of past life. While perchlorate is kinetically limited in Martian conditions, the intermediate species associated with its formation or decomposition, such as chlorate or chlorite, could oxidize Martian organic species. As a result, it is vital to understand the mechanism of perchlorate formation on Mars in order to determine its role in the degradation of organics. Here, we explore an alternate mechanism of formation of perchlorate by bombarding Cl-salts and Mars-relevant mineral mixtures with gamma radiation both with and without the presence of liquid water, under vacuum. Previous work has shown that OClO can form from both UV radiation and energetic electrons bombardment of Cl-ices or Cl-salts, which then reacts with either OH- or O-radicals to produce perchlorate. Past research has suggested that liquid water or ice is the source of these hydroxyl and oxygen radicals, which limits the location of perchlorate formation on Mars. We demonstrate that trace amounts of perchlorate are potentially formed in samples containing silica dioxide or iron oxide and Cl-salts both with and without liquid water. Perchlorate was also detected in a portion of samples that were not irradiated, suggesting possible contamination. We did not detect perchlorate in samples that contained sulfate minerals. If perchlorate was formed without liquid water, it is possible that oxide minerals could be a potential source of oxygen radicals

Perchlorate Regulatory Determination Fact Sheets

EPA Pesticide Factsheets

Fact sheets have been developed for the perchlorate regulatory determination corresponding to the following stages published in the Federal Register: Final, Supplemental request for comments, and Preliminary.

Engineered Intrinsic Bioremediation of Ammonium Perchlorate in Groundwater

DTIC Science & Technology

2010-12-01

German Collection of Microorganisms and Cell Cultures) GA Genetic Algorithms GA-ANN Genetic Algorithm Artificial Neural Network GMO genetically...for in situ treatment of perchlorate in groundwater. This is accomplished without the addition of genetically engineered microorganisms ( GMOs ) to the...perchlorate, even in the presence of oxygen and without the addition of genetically engineered microorganisms ( GMOs ) to the environment. This approach

DEVELOPMENT AND VALIDATION OF AN ION CHROMATOGRAPHIC METHOD FOR DETERMINING PERCHLORATE IN FERTILIZERS

EPA Science Inventory

A method has been developed for the determination of perchlorate in fertilizers. Materials are leached with deionized water to dissolve any soluble perchlorate compounds. Ion chromatographic separation is followed by suppressed conductivity for detection. Perchlorate is retained ...

A review of perchlorate (ClO4-) occurrence in fruits and vegetables.

PubMed

Calderón, R; Godoy, F; Escudey, M; Palma, P

2017-02-01

Since the 1990s, a large number of studies around the world have reported the presence of perchlorate in different types of environmental matrices. In view of their inherent characteristics, such as high solubility, mobility, persistence, and low affinity for the surface of soil, perchlorates are mobilized through the water-soil system and accumulate in edible plant species of high human consumption. However, the ingestion of food products containing perchlorate represents a potential health risk to people due to their adverse effects on thyroid, hormone, and neuronal development, mainly in infants and fetuses. At present, research has been centered on determining sources, fates, and remediation methods and not on its real extension in vegetables under farming conditions. This review presents a comprehensive overview and update of the frequent detection of perchlorate in fruits and vegetables produced and marketed around the world. Additionally, the impact of fertilizer on the potential addition of perchlorate to soil and its mobility in the water-soil-plant system is discussed. This review is organized into the following sections: sources of perchlorate, mobility in the water-soil system, presence in fruits and vegetables in different countries, international regulations, and toxicological studies. Finally, recommendations for future studies concerning perchlorate in fruits and vegetables are presented.

Preliminary analyses for perchlorate in selected natural materials and their derivative products

USGS Publications Warehouse

Orris, G.J.; Harvey, G.J.; Tsui, D.T.; Eldrige, J.E.

2003-01-01

Increasing concern about sources of perchlorate contamination in ground and surface waters has led to interest in identifying potential sources of natural perchlorate and products derived from these natural sources. To date, most perchlorate found in ground and surface waters has been attributed to its major uses as an oxidizer in solid propellants for rockets, in fireworks and other explosives, and a variety of other uses of man-made perchlorate salts. However, perchlorate found in the soils, surface water, and ground water of some locations cannot be linked to an anthropogenic source. This paper contains preliminary data on the detection and non-detection of perchlorate in a variety of natural materials and their products, including some fertilizer materials. These data were previously presented at two conferences; once in poster session and once orally (Harvey and others, 1999; Orris and others, 2000). Although the results presented here are included in a journal article awaiting publication, the lack of public information on this topic has led to repeated requests for the data used as the basis for our presentations in 1999 and 2000.

Bioreactor configurations for ex-situ treatment of perchlorate: a review.

PubMed

Sutton, Paul M

2006-12-01

The perchlorate anion has been detected in the drinking water of millions of people living in the United States. At perchlorate levels equal to or greater than 1 mg/L and where the water is not immediately used for household purposes, ex-situ biotreatment has been widely applied. The principal objective of this paper was to compare the technical and economic advantages and disadvantages of various bioreactor configurations in the treatment of low- and medium-strength perchlorate-contaminated aqueous streams. The ideal bioreactor configuration for this application should be able to operate efficiently while achieving a long solids retention time, be designed to promote physical-chemical adsorption in addition to biodegradation, and operate under plug-flow hydraulic conditions. To date, the granular activated carbon (GAC) or sand-media-based fluidized bed reactors (FBRs) and GAC, sand-, or plastic-media-based packed bed reactors (PBRs) have been the reactor configurations most widely applied for perchlorate treatment. Only the FBR configuration has been applied commercially. Commercial-scale cost information presented implies no economic advantage for the PBR relative to the FBR configuration. Full-scale application information provides evidence that the FBR is a good choice for treating perchlorate-contaminated aqueous streams.

Effects of perchlorate on growth of four wetland plants and its accumulation in plant tissues.

PubMed

He, Hongzhi; Gao, Haishuo; Chen, Guikui; Li, Huashou; Lin, Hai; Shu, Zhenzhen

2013-10-01

Perchlorate contamination in water is of concern because of uncertainties about toxicity and health effects, impact on ecosystems, and possible indirect exposure pathways to humans. Therefore, it is very important to investigate the ecotoxicology of perchlorate and to screen plant species for phytoremediation. Effects of perchlorate (20, 200, and 500 mg/L) on the growth of four wetland plants (Eichhornia crassipes, Acorus calamus L., Thalia dealbata, and Canna indica) as well as its accumulation in different plant tissues were investigated through water culture experiments. Twenty milligrams per liter of perchlorate had no significant effects on height, root length, aboveground part weight, root weight, and oxidizing power of roots of four plants, except A. calamus, and increasing concentrations of perchlorate showed that out of the four wetland plants, only A. calamus had a significant (p<0.05) dose-dependent decrease in these parameters. When treated with 500 mg/L perchlorate, these parameters and chlorophyll content in the leaf of plants showed significant decline contrasted to control groups, except the root length of E. crassipes and C. indica. The order of inhibition rates of perchlorate on root length, aboveground part weight and root weight, and oxidizing power of roots was: A. calamus > C. indica > T. dealbata > E. crassipes and on chlorophyll content in the leaf it was: A. calamus > T. dealbata > C. indica > E. crassipes. The higher the concentration of perchlorate used, the higher the amount of perchlorate accumulation in plants. Perchlorate accumulation in aboveground tissues was much higher than that in underground tissues and leaf was the main tissue for perchlorate accumulation. The order of perchlorate accumulation content and the bioconcentration factor in leaf of four plants was: E. crassipes > C. indica > T. dealbata > A. calamus. Therefore, E. crassipes might be an ideal plant with high tolerance ability and accumulation ability for constructing

Genetic Factors That Might Lead to Different Responses in Individuals Exposed to Perchlorate

PubMed Central

Scinicariello, Franco; Murray, H. Edward; Smith, Lester; Wilbur, Sharon; Fowler, Bruce A.

2005-01-01

Perchlorate has been detected in groundwater in many parts of the United States, and recent detection in vegetable and dairy food products indicates that contamination by perchlorate is more widespread than previously thought. Perchlorate is a competitive inhibitor of the sodium iodide symporter, the thyroid cell–surface protein responsible for transporting iodide from the plasma into the thyroid. An estimated 4.3% of the U.S. population is subclinically hypothyroid, and 6.9% of pregnant women may have low iodine intake. Congenital hypothyroidism affects 1 in 3,000 to 1 in 4,000 infants, and 15% of these cases have been attributed to genetic defects. Our objective in this review is to identify genetic biomarkers that would help define subpopulations sensitive to environmental perchlorate exposure. We review the literature to identify genetic defects involved in the iodination process of the thyroid hormone synthesis, particularly defects in iodide transport from circulation into the thyroid cell, defects in iodide transport from the thyroid cell to the follicular lumen (Pendred syndrome), and defects of iodide organification. Furthermore, we summarize relevant studies of perchlorate in humans. Because of perchlorate inhibition of iodide uptake, it is biologically plausible that chronic ingestion of perchlorate through contaminated sources may cause some degree of iodine discharge in populations that are genetically susceptible to defects in the iodination process of the thyroid hormone synthesis, thus deteriorating their conditions. We conclude that future studies linking human disease and environmental perchlorate exposure should consider the genetic makeup of the participants, actual perchlorate exposure levels, and individual iodine intake/excretion levels. PMID:16263499

THE REDUCTIVE TRANSFORMATION OF PERCHLORATE IN A FRESH WATER SEDIMENT: LABORATORY BATCH STUDIES

EPA Science Inventory

Perchlorate is widely used as a propellant in solid rocket fuel, and has recently been found in ground, surface, and drinking water, in many cases above the interim action level of 18 ppb. Perchlorate is recalcitrant to chemical reduction, however, studies of perchlorate in pure ...

THE REDUCTIVE TRANSFORMATION OF PERCHLORATE IN A FRESH WATER SEDIMENT: LABORATORY BATCH STUDIES.

EPA Science Inventory

Perchlorate is widely used as a propellant in solid rocket fuel, and has recently been found in ground, surface, and drinking water, in many cases above the interim action level of 18 ppb. Perchlorate is recalcitrant to chemical reduction, however, studies of perchlorate in pure ...

Perchlorate and iodide in whole blood samples from infants, children, and adults in Nanchang, China.

PubMed

Zhang, Tao; Wu, Qian; Sun, Hong Wen; Rao, Jia; Kannan, Kurunthachalam

2010-09-15

Perchlorate, ClO(4)(-), interferes with iodide (I(-)) uptake by the sodium-iodide symporter (NIS) and thereby affects thyroid hormone production in the body. Studies have reported human exposures to perchlorate based on measurements in urine, but little is known about the levels in blood. In this study, we determined concentrations of perchlorate, iodide, and other anions (e.g., chlorate [ClO(3)(-)], bromate [BrO(3)(-)], bromide [Br(-)]) in 131 whole blood samples collected from Chinese donors aged 0.4 to 90 yr, in Nanchang, China. Perchlorate, iodide, and bromide were detected in all of the samples analyzed, whereas chlorate was found in only 27% of the samples and bromate was found in only 2%. The mean (range) concentrations of perchlorate, iodide, and bromide were 2.68 (0.51-10.5), 42.6 (1.58-812), and 2120 (1050-4850) ng/mL, respectively. Perchlorate levels in blood from Nanchang adults were 10-fold greater than levels that have been previously reported for U.S. adults. The iodide/perchlorate molar ratio ranged from 3.05 to 15.3 for all age groups, and the ratio increased with age (r = 0.732, p < 0.01). Perchlorate and bromide concentrations decreased significantly with age, whereas iodide concentrations increased with age. No significant gender-related differences in blood perchlorate, iodide, or bromide levels were found. A significant negative correlation was found between the concentrations of perchlorate and iodide in blood. Exposure doses of perchlorate were estimated for infants, toddlers, children, adolescents, and adults based on the measured concentrations in blood, using a simple pharmacokinetic model. The mean exposure doses of perchlorate for our age groups ranged from 1.12 (adults) to 2.22 μg/kg bw/day (infants), values higher than the United States Environmental Protection Agency's (USEPA) reference dose (RfD: 0.7 μg/kg bw/day). This is the first study on perchlorate and iodide levels in whole blood from infants, toddlers, children, adolescents

Potassium bis(carbonato-O,O')(ethylenediamine-N,N')cobaltate(III) monohydrate at 173 K.

PubMed

Belai, N; Dickman, M H; Pope, M T

2001-07-01

The title salt, K[Co(C2H8N2)(CO3)2].H2O, consists of a distorted octahedral cobalt complex anion and a seven-coordinate potassium cation. Both metal atoms have crystallographic twofold symmetry, one C2 axis passing through the Co atom and C--C bond, and another along a short K--O (water) bond of 2.600 A (corrected for libration). The carbonate is bidentate to both cobalt and potassium and the water forms a hydrogen bond to a carbonate O atom.

High ozone increases soil perchlorate but does not affect foliar perchlorate content

USDA-ARS?s Scientific Manuscript database

Ozone (O3) is implicated in the natural source inventory of perchlorate (ClO4-), a hydrophilic salt that migrates to ground water and interferes with uptake of iodide in mammals, including humans. Tropospheric O3 is elevated in many areas. We previously showed (Grantz et al., 2013; Environmental Pol...

Perchlorate and nitrate treatment by ion exchange integrated with biological brine treatment.

PubMed

Lehman, S Geno; Badruzzaman, Mohammad; Adham, Samer; Roberts, Deborah J; Clifford, Dennis A

2008-02-01

Groundwater contaminated with perchlorate and nitrate was treated in a pilot plant using a commercially available ion exchange (IX) resin. Regenerant brine concentrate from the IX process, containing high perchlorate and nitrate, was treated biologically and the treated brine was reused in IX resin regeneration. The nitrate concentration of the feed water determined the exhaustion lifetime (i.e., regeneration frequency) of the resin; and the regeneration condition was determined by the perchlorate elution profile from the exhausted resin. The biological brine treatment system, using a salt-tolerant perchlorate- and nitrate-reducing culture, was housed in a sequencing batch reactor (SBR). The biological process consistently reduced perchlorate and nitrate concentrations in the spent brine to below the treatment goals of 500 microg ClO4(-)/L and 0.5mg NO3(-)-N/L determined by equilibrium multicomponent IX modeling. During 20 cycles of regeneration, the system consistently treated the drinking water to below the MCL of nitrate (10 mgNO3(-)-N/L) and the California Department of Health Services (CDHS) notification level of perchlorate (i.e., 6 microg/L). A conceptual cost analysis of the IX process estimated that perchlorate and nitrate treatment using the IX process with biological brine treatment to be approximately 20% less expensive than using the conventional IX with brine disposal.

Surprisingly facile CO2 insertion into cobalt alkoxide bonds: A theoretical investigation.

PubMed

Offermans, Willem K; Bizzarri, Claudia; Leitner, Walter; Müller, Thomas E

2015-01-01

Exploiting carbon dioxide as co-monomer with epoxides in the production of polycarbonates is economically highly attractive. More effective catalysts for this reaction are intensively being sought. To promote better understanding of the catalytic pathways, this study uses density functional theory calculations to elucidate the reaction step of CO2 insertion into cobalt(III)-alkoxide bonds, which is also the central step of metal catalysed carboxylation reactions. It was found that CO2 insertion into the cobalt(III)-alkoxide bond of [(2-hydroxyethoxy)Co(III)(salen)(L)] complexes (salen = N,N"-bis(salicyliden-1,6-diaminophenyl)) is exothermic, whereby the exothermicity depends on the trans-ligand L. The more electron-donating this ligand is, the more exothermic the insertion step is. Interestingly, we found that the activation barrier decreases with increasing exothermicity of the CO2 insertion. Hereby, a linear Brønsted-Evans-Polanyi relationship was found between the activation energy and the reaction energy.

Perchlorate: Health Effects and Technologies for Its Removal from Water Resources

PubMed Central

Srinivasan, Asha; Viraraghavan, Thiruvenkatachari

2009-01-01

Perchlorate has been found in drinking water and surface waters in the United States and Canada. It is primarily associated with release from defense and military operations. Natural sources include certain fertilizers and potash ores. Although it is a strong oxidant, perchlorate is very persistent in the environment. At high concentrations perchlorate can affect the thyroid gland by inhibiting the uptake of iodine. A maximum contaminant level has not been set, while a guidance value of 6 ppb has been suggested by Health Canada. Perchlorate is measured in environmental samples primarily by ion chromatography. It can be removed from water by anion exchange or membrane filtration. Biological and chemical processes are also effective in removing this species from water. PMID:19440526

RAMAN SPECTRAL ANALYSIS OF PERCHLORATE CONTAMINATION IN COMMONLY-USED FERTILIZERS

EPA Science Inventory

Raman spectroscopy (RS) was used for qualitative and quantitative analysis of perchlorate (ClO4-1) in 30+ commonly-used fertilizers. Perchlorate contamination is emerging as an important environmental issue since its discovery in water resources that are widely used for drinking...

Detection of hexamethonium-perchlorate association complexes using NACE-MS.

PubMed

Groom, Carl A; Hawari, Jalal

2007-02-01

Perchlorate (ClO(4) (+)) and other chlorine oxide anions were observed to complex weakly with hexamethonium (1,6-bis-(trimethylammonium)-hexane) in both aqueous and polar nonaqueous solvents. The resultant positively charged complexes were resolved by NACE using 2-propanol/acetone electrolytes prior to mass spectrometric detection using an Agilent(3D)CE system coupled to a Bruker Esquire 3000+ quadrupole IT mass detector. Using electrokinetic injection, the method detection limit for perchlorate in nonaqueous media was 10 microg/L. The isotope patterns due to the presence of (35)Cl and (37)Cl in complex mass spectra allowed for unambiguous identification of perchlorate, chlorate (ClO(3) (+)), chlorite (ClO(2) (+)), and chloride (Cl(+)) in photoreaction samples.

Comparative cytotoxicity and genotoxicity of cobalt (II, III) oxide, iron (III) oxide, silicon dioxide, and aluminum oxide nanoparticles on human lymphocytes in vitro.

PubMed

Rajiv, S; Jerobin, J; Saranya, V; Nainawat, M; Sharma, A; Makwana, P; Gayathri, C; Bharath, L; Singh, M; Kumar, M; Mukherjee, A; Chandrasekaran, N

2016-02-01

Despite the extensive use of nanoparticles (NPs) in various fields, adequate knowledge of human health risk and potential toxicity is still lacking. The human lymphocytes play a major role in the immune system, and it can alter the antioxidant level when exposed to NPs. Identification of the hazardous NPs was done using in vitro toxicity tests and this study mainly focuses on the comparative in vitro cytotoxicity and genotoxicity of four different NPs including cobalt (II, III) oxide (Co3O4), iron (III) oxide (Fe2O3), silicon dioxide (SiO2), and aluminum oxide (Al2O3) on human lymphocytes. The Co3O4 NPs showed decrease in cellular viability and increase in cell membrane damage followed by Fe2O3, SiO2, and Al2O3 NPs in a dose-dependent manner after 24 h of exposure to human lymphocytes. The oxidative stress was evidenced in human lymphocytes by the induction of reactive oxygen species, lipid peroxidation, and depletion of catalase, reduced glutathione, and superoxide dismutase. The Al2O3 NPs showed the least DNA damage when compared with all the other NPs. Chromosomal aberration was observed at 100 µg/ml when exposed to Co3O4 NPs and Fe2O3 NPs. The alteration in the level of antioxidant caused DNA damage and chromosomal aberration in human lymphocytes. © The Author(s) 2015.

Stability of low levels of perchlorate in drinking water and natural water samples

USGS Publications Warehouse

Stetson, S.J.; Wanty, R.B.; Helsel, D.R.; Kalkhoff, S.J.; Macalady, D.L.

2006-01-01

Perchlorate ion (ClO4-) is an environmental contaminant of growing concern due to its potential human health effects, impact on aquatic and land animals, and widespread occurrence throughout the United States. The determination of perchlorate cannot normally be carried out in the field. As such, water samples for perchlorate analysis are often shipped to a central laboratory, where they may be stored for a significant period before analysis. The stability of perchlorate ion in various types of commonly encountered water samples has not been generally examined-the effect of such storage is thus not known. In the present study, the long-term stability of perchlorate ion in deionized water, tap water, ground water, and surface water was examined. Sample sets containing approximately 1000, 100, 1.0, and 0.5 ??g l-1 perchlorate ion in deionized water and also in local tap water were formulated. These samples were analyzed by ion chromatography for perchlorate ion concentration against freshly prepared standards every 24 h for the first 7 days, biweekly for the next 4 weeks, and periodically after that for a total of 400 or 610 days for the two lowest concentrations and a total of 428 or 638 days for the high concentrations. Ground and surface water samples containing perchlorate were collected, held and analyzed for perchlorate concentration periodically over at least 360 days. All samples except for the surface water samples were found to be stable for the duration of the study, allowing for holding times of at least 300 days for ground water samples and at least 90 days for surface water samples. ?? 2006 Elsevier B.V. All rights reserved.

Growth and Survival of Perchlorate-Reducing Bacteria in Media Containing Elevated Perchlorate Concentrations and UV-C Conditions

NASA Technical Reports Server (NTRS)

Bywaters, K. F.; Mckay, C. P.; Quinn, R. C.

2017-01-01

Introduction: The identification of perchlorate (ClO4(-)) on Mars has led to the possibility that complete redox couples are available for microbial metabolism in contemporary surface environments. Perchlorate-reducing bacteria (PRB) utilize ClO4(-) and chlorate (ClO3(-)) as terminal electron acceptors due to the high reduction potential. Additionally, ClO4(-) salts have been suggested as a possible source of brines on Mars and spectral evidence indicates that the hydration of ClO4(-) salts in the regolith of Martian is linked to the surface recurring slope lineae (RSL). For these reasons PRB may serve as analog organisms for possible life on Mars. However, there is very little information on the viability of PRB in aqueous environments that contain high levels of perchlorate Microorganisms on or near the surface of Mars, such as in the RSL, would potentially be exposed to high-salinity and high ultraviolet radiation environments. Under these extreme conditions, microorganisms must possess mechanisms for maintaining continued high genome fidelity. To assess possible microbial viability in contemporary Mars analog environments we are investigating the tolerance of two PRB strains in aqueous conditions under high UV-C conditions and high ClO4(-) concentrations.

Effect of Ascorbate on the Cyanide-Scavenging Capability of Cobalt(III) meso-Tetra(4-N-methylpyridyl)porphine Pentaiodide: Deactivation by Reduction?

PubMed

Benz, Oscar S; Yuan, Quan; Cronican, Andrea A; Peterson, Jim; Pearce, Linda L

2016-03-21

The Co(III)-containing water-soluble metalloporphyrin cobalt(III) meso-tetra(4-N-methylpyridyl)porphine pentaiodide (Co(III)TMPyP) is a potential cyanide-scavenging agent. The rate of reduction of Co(III)TMPyP by ascorbate is facile enough that conversion to the Co(II)-containing Co(II)TMPyP should occur within minutes at prevailing in vivo levels of the reductant. It follows that any cyanide-decorporating capability of the metalloporphyrin should depend more on the cyanide-binding characteristics of Co(II)TMPyP than those of the administered form, Co(III)TMPyP. Addition of cyanide to buffered aqueous solutions of Co(II)TMPyP (pH 7.4, 25-37 °C) results in quite rapid (k2 = ∼10(3) M(-1) s(-1)) binding/substitution of cyanide anion in the two available axial positions with high affinity (K'β = 10(10) to 10(11)). Electron paramagnetic resonance spectroscopic measurements and cyclic voltammetry indicate that cyanide induces oxidation to the Co(III)-containing dicyano species. The constraints that these observations put on plausible mechanisms for the reaction of Co(II)TMPyP with cyanide are discussed. Experiments in which Co(III)TMPyP and cyanide were added to freshly drawn mouse blood showed the same sequence of reactions (metalloporphyrin reduction → cyanide binding/substitution → reoxidation) to occur. Therefore, in cyanide-scavenging applications with this metalloporphyrin, we should be taking advantage of both the improved rate of ligand substitution at Co(II) compared to that at Co(III) and the increased affinity of Co(III) for anionic ligands compared to that of Co(II). Finally, using an established sublethal mouse model for cyanide intoxication, Co(III)TMPyP, administered either 5 min before (prophylaxis) or 1 min after the toxicant, is shown to have very significant antidotal capability. Possible explanations for the results of a previous contradictory study, which failed to find any prophylactic effect of Co(III)TMPyP toward cyanide intoxication, are

Long-Range Transport of Perchlorate Observed in the Atmospheric Aerosols Collected at Okinawa Island, Japan

NASA Astrophysics Data System (ADS)

Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Arakaki, T.; Tanahara, A.; Oomori, T.; Miyagi, T.; Kadena, H.; Ishizaki, T.; Nakama, F.

2007-12-01

The study of perchlorate has become quite active in the U.S. in the last several years. Perchlorate has been recognized as a new environmental pollutant and it attracted much attention quickly in the world. The health concern about perchlorate stems from the fact that it displaces iodide in the thyroid gland, while iodine-containing thyroid hormones are essential for proper neural development from the fetal stage through the first years of life. In this study, we determined the concentrations of perchlorate ion present in the atmospheric aerosols collected in Okinawa Island, Japan. We then examined the relationships between the perchlorate concentrations and the environmental parameters and the climatic conditions peculiar to Okinawa. Bulk aerosol samples were collected on quartz filters by using a high volume air sampler at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS). Each sampling duration was one week. The quartz filters with aerosols were stirred with Milli-Q pure water for three hours before perchlorate ion was extracted. The extracted perchlorate ion concentrations were determined by ion chromatography (ICS-2000, DIONEX). The mean perchlorate concentration for the samples collected at CHAAMS was 1.83 ng/m3, and the minimum was 0.18 ng/m3. The samples collected during November 21-27, 2005, January 23-30, 2006 and April 24-01, 2006 had highest perchlorate concentrations. For these three samples, we performed back trajectory analysis, and found that the air mass for the three samples arrived from the Asian continent. A relatively strong correlation (r2 = 0.55) was found between perchlorate and nss-sulfate concentrations for the CHAAMS samples. Furthermore, we analyzed perchlorate in the soils and the fertilizers used for sugar cane farming around the CHAAMS area. The Milli-Q extract of the soil and the fertilizers did not contain any detectable levels of perchlorate ions. Therefore, it was suggested that perchlorate found in the atmospheric

Adaptive evolution of Desulfovibrio alaskensis G20 for developing resistance to perchlorate

NASA Astrophysics Data System (ADS)

Mehta-Kolte, M. G.; Youngblut, M.; Redford, S.; Gregoire, P.; Carlson, H. K.; Coates, J. D.

2015-12-01

Due to its toxic, explosive, and corrosive nature, inadvertent biological H2S production by sulfate reducing microorganisms (SRM) poses significant health and industrial operational risks. Anthropogenic sources are dominated by the oil industry where H2S in reservoir gases and fluids has an associated annual cost estimated at $90 billion globally. Our previous studies have identified perchlorate (ClO4-) as a selective and potent inhibitor of SRM in pure culture and complex microbial ecosystems. However, constant addition of inhibitors like perchlorate to natural ecosystems may result in a new adaptive selective pressure on SRM populations. With this in mind we investigated the ability of Desulfovibrio alaskensis G20, a model oil reservoir SRM, to adapt to perchlorate and develop a resistance. Serial transfers of three parallel cultures with increasing concentrations of perchlorate up to 100 mM were generated and compared to wild-type strains that were transferred for same number of generations in absence of perchlorate. Genome sequencing revealed that all three adapted strains had single non-synonymous single-nucleotide polymorphisms in the same gene, Dde_2265, the sulfate adenylytransferase (ATP sulfurylase (ATPS)) (EC 2.7.7.4). ATPS catalyzes the first committed step in sulfate reduction and is essential in all SRM. IC50s against growth for these evolved strains demonstrated a three-fold increased resistance to perchlorate compared to wild-type controls. These evolved strains also had 5x higher transcriptional abundance of Dde_2265 compared to the wild-type strain. Biochemical characterization of the purified ATPS enzyme from both wild-type and the evolved strain showed that the mutant ATPS from the evolved strain was resistant to perchlorate inhibition of ATP turnover with a KI for perchlorate that was 3x greater relative to the wild-type ATPS. These results demonstrate that a single-base pair mutation in ATPS can have a significant impact on developing

PHYTOREMEDIATION OF PERCHLORATE AND N-NITROSODIMETHYLAMINE AS SINGLE AND CO-CONTAMINANTS

EPA Science Inventory

Although potential plant species suitable for phytoremediation of perchlorate and the phytoprocesses involved (rhizodegradation and phytodegradation) have been identified in previous research, regulators and some critics argue that plants recycle the perchlorate fract...

The thyroid endocrine disruptor perchlorate affects reproduction, growth, and survival of mosquitofish.

PubMed

Park, June-Woo; Rinchard, Jacques; Liu, Fujun; Anderson, Todd A; Kendall, Ronald J; Theodorakis, Christopher W

2006-03-01

The perchlorate anion--an oxidizer found in rockets, missiles, some ammunition, flares, airbags, and fireworks--occurs as a contaminant in ground and surface water in many parts of the United States. Its toxic effects include inhibition of thyroid hormone synthesis. To investigate its chronic toxicity, mosquitofish (Gambusia holbrooki) adults and fry were exposed to aqueous sodium perchlorate at 1, 10, and 100mg/L, and growth and reproductive performance (fecundity, eggs/embryos mass, and gonadosomatic index [GSI]) were determined. Five-day acute toxicity tests were also performed. Perchlorate had a stimulatory effect on fecundity, GSI, and egg/embryo mass, at least for some treatments. The LC50 of sodium perchlorate was 404 mg/L. Growth was enhanced at 1mg/L but inhibited at 10mg/L. These results suggest that, at environmentally relevant concentrations, perchlorate does not induce acutely toxic effects but may have mild stimulatory or hormetic effects on fitness parameters in this species.

Fine-Tuning the Activity of Metal–Organic Framework Supported Cobalt Catalysts for the Oxidative Dehydrogenation of Propane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhanyong; Peters, Aaron W.; Platero-Prats, Ana E.

Few-atom cobalt-oxide clusters, when dispersed on a Zr-based metal–organic framework (MOF) NU-1000, have previously been shown to be active for the oxidative dehydrogenation (ODH) of propane at low temperatures (< 230 °C), affording a selective and stable propene production catalyst. In our current work, a series of promoter ions with varying Lewis acidity, including Ni(II), Zn(II), Al(III), Ti(IV) and Mo(VI), are anchored as metal-oxide,hydroxide clusters to NU-1000 via SIM (solvothermal deposition within MOFs–specifically the nodes) followed by incorporation of Co(II) ions via vapor-phase AIM (atomic layer deposition (ALD) in MOFs). This process yields a series of NU-1000-supported bimetallic-oxo,hydroxo,aqua clusters. Usingmore » difference envelope density (DED) analyses, the spatial locations of the promoter ions and catalytic cobalt ions are determined. For all samples the SIM-anchored promoter ions are sited between pairs of Zr 6 nodes along the MOF c-axis (channel-aligned axis) whereas the location of the AIM-anchored cobalt ions varies depending on the identity of promoter metal ion. With Ni(II)-, Al(III)-, or Ti(IV)-containing clusters as promoters, the oxy-cobalt species are sited atop the promoter sites; with Mo(VI) they grow exclusively on the MOF nodes sites (hexa-Zr(IV)- oxo,hydroxo,aqua units); with Zn(II) they grow on both the node and promoter. The NU-1000- supported bimetallic-oxide clusters are active for propane ODH after thermal activation under O 2 to open a cobalt coordination site and to oxidize Co(II) to Co(III), as evidenced by operando Xray absorption spectroscopy at the Co K-edge. The cobalt component is exclusively responsible for the observed catalysis. In accord with the decreasing Lewis acidity of the promoter ion, catalytic activity increases in the order: Mo(VI)« less

Fine-Tuning the Activity of Metal–Organic Framework Supported Cobalt Catalysts for the Oxidative Dehydrogenation of Propane

DOE PAGES

Li, Zhanyong; Peters, Aaron W.; Platero-Prats, Ana E.; ...

2017-10-04

Few-atom cobalt-oxide clusters, when dispersed on a Zr-based metal–organic framework (MOF) NU-1000, have previously been shown to be active for the oxidative dehydrogenation (ODH) of propane at low temperatures (< 230 °C), affording a selective and stable propene production catalyst. In our current work, a series of promoter ions with varying Lewis acidity, including Ni(II), Zn(II), Al(III), Ti(IV) and Mo(VI), are anchored as metal-oxide,hydroxide clusters to NU-1000 via SIM (solvothermal deposition within MOFs–specifically the nodes) followed by incorporation of Co(II) ions via vapor-phase AIM (atomic layer deposition (ALD) in MOFs). This process yields a series of NU-1000-supported bimetallic-oxo,hydroxo,aqua clusters. Usingmore » difference envelope density (DED) analyses, the spatial locations of the promoter ions and catalytic cobalt ions are determined. For all samples the SIM-anchored promoter ions are sited between pairs of Zr 6 nodes along the MOF c-axis (channel-aligned axis) whereas the location of the AIM-anchored cobalt ions varies depending on the identity of promoter metal ion. With Ni(II)-, Al(III)-, or Ti(IV)-containing clusters as promoters, the oxy-cobalt species are sited atop the promoter sites; with Mo(VI) they grow exclusively on the MOF nodes sites (hexa-Zr(IV)- oxo,hydroxo,aqua units); with Zn(II) they grow on both the node and promoter. The NU-1000- supported bimetallic-oxide clusters are active for propane ODH after thermal activation under O 2 to open a cobalt coordination site and to oxidize Co(II) to Co(III), as evidenced by operando Xray absorption spectroscopy at the Co K-edge. The cobalt component is exclusively responsible for the observed catalysis. In accord with the decreasing Lewis acidity of the promoter ion, catalytic activity increases in the order: Mo(VI)« less

Thyroid Hormones and Moderate Exposure to Perchlorate during Pregnancy in Women in Southern California.

PubMed

Steinmaus, Craig; Pearl, Michelle; Kharrazi, Martin; Blount, Benjamin C; Miller, Mark D; Pearce, Elizabeth N; Valentin-Blasini, Liza; DeLorenze, Gerald; Hoofnagle, Andrew N; Liaw, Jane

2016-06-01

Findings from national surveys suggest that everyone in the United States is exposed to perchlorate. At high doses, perchlorate, thiocyanate, and nitrate inhibit iodide uptake into the thyroid and decrease thyroid hormone production. Small changes in thyroid hormones during pregnancy, including changes within normal reference ranges, have been linked to cognitive function declines in the offspring. We evaluated the potential effects of low environmental exposures to perchlorate on thyroid function. Serum thyroid hormones and anti-thyroid antibodies and urinary perchlorate, thiocyanate, nitrate, and iodide concentrations were measured in 1,880 pregnant women from San Diego County, California, during 2000-2003, a period when much of the area's water supply was contaminated from an industrial plant with perchlorate at levels near the 2007 California regulatory standard of 6 μg/L. Linear regression was used to evaluate associations between urinary perchlorate and serum thyroid hormone concentrations in models adjusted for urinary creatinine and thiocyanate, maternal age and education, ethnicity, and gestational age at serum collection. The median urinary perchlorate concentration was 6.5 μg/L, about two times higher than in the general U.S. Adjusted associations were identified between increasing log10 perchlorate and decreasing total thyroxine (T4) [regression coefficient (β) = -0.70; 95% CI: -1.06, -0.34], decreasing free thyroxine (fT4) (β = -0.053; 95% CI: -0.092, -0.013), and increasing log10 thyroid-stimulating hormone (β = 0.071; 95% CI: 0.008, 0.133). These results suggest that environmental perchlorate exposures may affect thyroid hormone production during pregnancy. This could have implications for public health given widespread perchlorate exposure and the importance of thyroid hormone in fetal neurodevelopment. Steinmaus C, Pearl M, Kharrazi M, Blount BC, Miller MD, Pearce EN, Valentin-Blasini L, DeLorenze G, Hoofnagle AN, Liaw J. 2016. Thyroid

Exposure to perchlorate induces the formation of macrophage aggregates in the trunk kidney of zebrafish and mosquitofish

USGS Publications Warehouse

Capps, T.; Mukhi, S.; Rinchard, J.J.; Theodorakis, C.W.; Blazer, V.S.; Patino, R.

2004-01-01

Environmental contamination of ground and surface waters by perchlorate, derived from ammonium perchlorate (AP) and other perchlorate salts, is of increasing concern. Exposure to perchlorate can impair the thyroid endocrine system, which is thought to modulate renal and immune function in vertebrates. This study with zebrafish Danio rerio and eastern mosquitofish Gambusia holbrooki examined the histological effects of perchlorate on the trunk kidney, which in teleosts serves excretory and hemopoietic functions and therefore may be a target of perchlorate effects. Adult zebrafish of both sexes were exposed in the laboratory to waterborne, AP-derived perchlorate at measured concentrations of 18 mg/L for 8 weeks. Adult male mosquitofish were exposed to waterborne sodium perchlorate at measured perchlorate concentrations of 1-92 mg/L for 8 weeks. Control fish were kept in untreated water. The region of the body cavity containing the trunk kidney was processed from each fish for histological analysis. Macrophage aggregates (MAs), possible markers of contaminant exposure or immunotoxic effect, were present in the hemopoietic region of the kidney in both species exposed to perchlorate. The estimated percent area of kidney sections occupied by MAs was greater in zebrafish exposed to perchlorate at 18 mg/L (P < 0.05) than in controls. In male mosquitofish, the incidence of renal MAs increased proportionally with sodium perchlorate concentration and was significantly different from that of controls at 92 mg/L (P < 0.05). These observations confirm that in fish the kidney is affected by exposure to perchlorate. The concentrations of perchlorate at which the effects were noted are relatively high but within the range reported in some contaminated habitats.

Mechanistic Investigations of Water Oxidation by a Molecular Cobalt Oxide Analogue: Evidence for a Highly Oxidized Intermediate and Exclusive Terminal Oxo Participation.

PubMed

Nguyen, Andy I; Ziegler, Micah S; Oña-Burgos, Pascual; Sturzbecher-Hohne, Manuel; Kim, Wooyul; Bellone, Donatela E; Tilley, T Don

2015-10-14

Artificial photosynthesis (AP) promises to replace society's dependence on fossil energy resources via conversion of sunlight into sustainable, carbon-neutral fuels. However, large-scale AP implementation remains impeded by a dearth of cheap, efficient catalysts for the oxygen evolution reaction (OER). Cobalt oxide materials can catalyze the OER and are potentially scalable due to the abundance of cobalt in the Earth's crust; unfortunately, the activity of these materials is insufficient for practical AP implementation. Attempts to improve cobalt oxide's activity have been stymied by limited mechanistic understanding that stems from the inherent difficulty of characterizing structure and reactivity at surfaces of heterogeneous materials. While previous studies on cobalt oxide revealed the intermediacy of the unusual Co(IV) oxidation state, much remains unknown, including whether bridging or terminal oxo ligands form O2 and what the relevant oxidation states are. We have addressed these issues by employing a homogeneous model for cobalt oxide, the [Co(III)4] cubane (Co4O4(OAc)4py4, py = pyridine, OAc = acetate), that can be oxidized to the [Co(IV)Co(III)3] state. Upon addition of 1 equiv of sodium hydroxide, the [Co(III)4] cubane is regenerated with stoichiometric formation of O2. Oxygen isotopic labeling experiments demonstrate that the cubane core remains intact during this stoichiometric OER, implying that terminal oxo ligands are responsible for forming O2. The OER is also examined with stopped-flow UV-visible spectroscopy, and its kinetic behavior is modeled, to surprisingly reveal that O2 formation requires disproportionation of the [Co(IV)Co(III)3] state to generate an even higher oxidation state, formally [Co(V)Co(III)3] or [Co(IV)2Co(III)2]. The mechanistic understanding provided by these results should accelerate the development of OER catalysts leading to increasingly efficient AP systems.

Effects of Ammonium Perchlorate on Thyroid Function in Developing Fathead Minnows, Pimephales promelas

PubMed Central

Crane, Helen M.; Pickford, Daniel B.; Hutchinson, Thomas H.; Brown, J. Anne

2005-01-01

Perchlorate is a known environmental contaminant, largely due to widespread military use as a propellant. Perchlorate acts pharmacologically as a competitive inhibitor of thyroidal iodide uptake in mammals, but the impacts of perchlorate contamination in aquatic ecosystems and, in particular, the effects on fish are unclear. Our studies aimed to investigate the effects of concentrations of ammonium perchlorate that can occur in the environment (1, 10, and 100 mg/L) on the development of fathead minnows, Pimephales promelas. For these studies, exposures started with embryos of < 24-hr postfertilization and were terminated after 28 days. Serial sectioning of thyroid follicles showed thyroid hyperplasia with increased follicular epithelial cell height and reduced colloid in all groups of fish that had been exposed to perchlorate for 28 days, compared with control fish. Whole-body thyroxine (T4) content (a measure of total circulating T4) in fish exposed to 100 mg/L perchlorate was elevated compared with the T4 content of control fish, but 3,5,3′-triiodothyronine (T3) content was not significantly affected in any exposure group. Despite the apparent regulation of T3, after 28 days of exposure to ammonium perchlorate, fish exposed to the two higher levels (10 and 100 mg/L) were developmentally retarded, with a lack of scales and poor pigmentation, and significantly lower wet weight and standard length than were control fish. Our study indicates that environmental levels of ammonium perchlorate affect thyroid function in fish and that in the early life stages these effects may be associated with developmental retardation. PMID:15811828

Effects of ammonium perchlorate on the reproductive performance and thyroid follicle histology of zebrafish

USGS Publications Warehouse

Patino, R.; Wainscott, M.R.; Cruz-Li, E. I.; Balakrishnan, S.; McMurry, C.; Blazer, V.S.; Anderson, T.A.

2003-01-01

Adult zebrafish were reared up to eight weeks in control water or in water containing ammonium perchlorate (AP) at measured perchlorate concentrations of 18 (environmentally relevant, high) and 677 ppm. Groups of eight females were paired with four males on a weekly basis to assess AP effects on spawned egg volume, an index of reproductive performance. All treatments were applied to four to five spawning replicates. At 677 ppm, spawn volume was reduced within one week and became negligible after four weeks. At 18 ppm, spawn volume was unaffected even after eight weeks. Also, perchlorate at 18 ppm did not affect percentage egg fertilization. Fish were collected at the end of the exposures (677 ppm, four weeks; control and 18 ppm, eight weeks) for whole-body perchlorate content and thyroid histopathological analysis. Fish perchlorate levels were about one-hundredth of those of treatment water levels, indicating that waterborne perchlorate does not accumulate in whole fish. At 677 ppm for four weeks, perchlorate caused thyroid follicle cell (nuclear) hypertrophy and angiogenesis, whereas at 18 ppm for eight weeks, its effects were more pronounced and included hypertrophy, angiogenesis, hyperplasia, and colloid depletion. In conclusion, an eight-week exposure of adult zebrafish to 18 ppm perchlorate (high environmentally relevant concentrations) affected the histological condition of their thyroid follicles but not their reproductive performance. The effect of 677 ppm perchlorate on reproduction may be due to extrathyroidal toxicity. Further research is needed to determine if AP at lower environmentally relevant concentrations also affects the thyroid follicles of zebrafish.

Validation of a Novel Bioassay for Low-level Perchlorate Determination

DTIC Science & Technology

2014-04-01

was not attractive, since these reduce PMS2 , and it was thought they would interfere with the stoichiometry of NADH and perchlorate in the bioassay...these reduce PMS2 directly, and would interfere with the stoichiometry of NADH and perchlorate in the bioassay. Thus the only approach that could be

Validation of a Novel Bioassay for Low-level Perchlorate Determination

DTIC Science & Technology

2013-05-01

since these reduce PMS2 , and it was thought they would interfere with the stoichiometry of NADH and perchlorate in the bioassay. With regard to the...reduce PMS2 directly, and would interfere with the stoichiometry of NADH and perchlorate in the bioassay. Thus the only approach that could be

Cobalt dopant with deep redox potential for organometal halide hybrid solar cells.

PubMed

Koh, Teck Ming; Dharani, Sabba; Li, Hairong; Prabhakar, Rajiv Ramanujam; Mathews, Nripan; Grimsdale, Andrew C; Mhaisalkar, Subodh G

2014-07-01

In this work, we report a new cobalt(III) complex, tris[2-(1H-pyrazol-1-yl)pyrimidine]cobalt(III) tris[bis(trifluoromethylsulfonyl)imide] (MY11), with deep redox potential (1.27 V vs NHE) as dopant for 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD). This dopant possesses, to the best of our knowledge, the deepest redox potential among all cobalt-based dopants used in solar cell applications, allowing it to dope a wide range of hole-conductors. We demonstrate the tuning of redox potential of the Co dopant by incorporating pyrimidine moiety in the ligand. We characterize the optical and electrochemical properties of the newly synthesized dopant and show impressive spiro-to-spiro(+) conversion. Lastly, we fabricate high efficiency perovskite-based solar cells using MY11 as dopant for molecular hole-conductor, spiro-OMeTAD, to reveal the impact of this dopant in photovoltaic performance. An overall power conversion efficiency of 12% is achieved using MY11 as p-type dopant to spiro-OMeTAD. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simple Preparation and NMR Analysis of mer and fac Isomers of Tris(1,1,1-trifluoro-2,4-pentanedionato)cobalt(III). An Experiment for the Inorganic Chemistry Laboratory

NASA Astrophysics Data System (ADS)

Jensen, Ashley W.; O'Brien, Brian A.

2001-07-01

A one-step procedure for the preparation of tris(1,1,1-trifluoro-2,4-pentanedionato)cobalt(III) from hydrated cobalt(II) carbonate and 10% hydrogen peroxide, in which tert-butyl alcohol is used as a component of the solvent, is described. The procedure is short, simple, and less hazardous than procedures reported in the literature, and the starting materials are readily available and inexpensive. The product is a mixture of mer and fac isomers that can be separated by silica gel chromatography with toluene as the eluent. Thin-layer chromatography is used to obtain a collective class sample of each isomer for 1H, 13C, and 19F NMR analysis. The NMR analyses clearly illustrate the threefold rotational symmetry of the fac isomer and the lack of symmetry of the mer isomer. Detailed NMR data are provided for each isomer.

ALTERNATIVE TECHNIQUES FOR MEASUREMENT OF PERCHLORATE IN FERTILIZER AND ENVIRONMENTAL SAMPLES

EPA Science Inventory

The Perchlorate anion has been implicated as a potentially serious environmental pollutant, being found in drinking water and irrigated crops. Commercial fertilizers have recently been shown to contain high levels of Perchlorate impurities and thus be potentially important source...

Removal of Perchlorate and Chlorate in Aquatic SystemsUsing Integrated Technologies

EPA Science Inventory

Because of its extremely low concentrations and strong resistance to most treatment technologies, perchlorate has become one of the biggest challenges currently being faced by the drinking water industry. Few studies have looked at electrochemical reduction of aqueous perchlorate...

Blood doping by cobalt. Should we measure cobalt in athletes?

PubMed

Lippi, Giuseppe; Franchini, Massimo; Guidi, Gian Cesare

2006-07-24

Blood doping is commonplace in competitive athletes who seek to enhance their aerobic performances through illicit techniques. Cobalt, a naturally-occurring element with properties similar to those of iron and nickel, induces a marked and stable polycythemic response through a more efficient transcription of the erythropoietin gene. Although little information is available so far on cobalt metabolism, reference value ranges or supplementation in athletes, there is emerging evidence that cobalt is used as a supplement and increased serum concentrations are occasionally observed in athletes. Therefore, given the athlete's connatural inclination to experiment with innovative, unfair and potentially unhealthy doping techniques, cobalt administration might soon become the most suited complement or surrogate for erythropoiesis-stimulating substances. Nevertheless, cobalt administration is not free from unsafe consequences, which involve toxic effects on heart, liver, kidney, thyroid and cancer promotion. Cobalt is easily purchasable, inexpensive and not currently comprehended within the World Anti-Doping Agency prohibited list. Moreover, available techniques for measuring whole blood, serum, plasma or urinary cobalt involve analytic approaches which are currently not practical for antidoping laboratories. Thus more research on cobalt metabolism in athletes is compelling, along with implementation of effective strategies to unmask this potentially deleterious doping practice.

Spatial Variability of Perchlorate along a Traverse Route from Zhongshan Station to Dome A, East Antarctica

NASA Astrophysics Data System (ADS)

Jiang, S.; Cole-Dai, J.; Li, Y.; An, C.

2016-12-01

Snow deposition and accumulation on the Antarctic ice sheet preserve records of climatic change, as well as those of chemical characteristics of the environment. Chemical composition of snow and ice cores can be used to track the sources of important substances including pollutants and to investigate relationships between atmospheric chemistry and climatic conditions. Recent development in analytical methodology has enabled the determination of ultra-trace levels of perchlorate in polar snow. We have measured perchlorate concentrations in surface snow samples collected along a traverse route from Zhongshan Station to Dome A in East Antarctica to determine the level of atmospheric perchlorate in East Antarctica and to assess the spatial variability of perchlorate along the traverse route. Results show that the perchlorate concentrations vary between 32 and 200 ng kg-1, with an average of 104.3 ng kg-1. And perchlorate concentration profile presents regional variation patterns along the traverse route. In the coastal region, perchlorate concentration displays an apparent decreasing relationship with increasing distance inland; it exhibits no apparent trend in the intermediate region from 200 to 1000 km. The inland region from 1000 to 1244 km presents a generally increasing trend of perchlorate concentration approaching the dome. Different rates of atmospheric production, dilution by snow accumulation and re-deposition of snow-emitted perchlorate (post-depositional change) are the three possible factors influencing the spatial variability of perchlorate over Antarctica.

Soil Flushing Through a Thick Vadose Zone: Perchlorate Removal Documented at Edwards AFB, California

NASA Astrophysics Data System (ADS)

Battey, T. F.; Shepard, A. J.; Tait, R. J.

2007-12-01

There are currently few viable alternatives for perchlorate remediation in the vadose zone, particularly for the relatively thick vadose zones that are typical in the arid southwest where many perchlorate sites occur. Perchlorate in the vadose zone occurs in the form of highly soluble salts that may represent a risk to human or ecological receptors, and may also represent a threat to the underlying groundwater. A soil flushing treatability study was conducted at Edwards Air Force Base in the Mojave Desert of southern California at a site with a 129-foot thick vadose zone consisting primarily of clayey sand. This study utilized an infiltration gallery in conjunction with extraction, treatment, and re-injection of groundwater at the site, which contained perchlorate-contaminated soil and groundwater. The study objective was to evaluate the effectiveness of the infiltration gallery to 1) introduce treated groundwater back into the aquifer and 2) wash the perchlorate from the vadose zone soils to the aquifer. The infiltration gallery consisted of slotted PVC pipes within a highly permeable engineered bed of washed gravel. The initial water introduced into the gallery was amended with potassium bromide tracer. A downhole neutron probe was used to track the movement of the wetting front downward and outward from the gallery. Successive neutron measurements in vertical access tubes revealed that the introduced water reached the 125-foot bottom of the access tubes 14 weeks after the water was introduced into the gallery. The bromide tracer was detected in groundwater immediately below the gallery approximately 1 week later. The infiltration gallery was able to sustain an average flow rate of 2.3 gallons per minute. Prior to infiltration, the perchlorate concentration in groundwater below the gallery was 4,500 µg/L. Approximately 18 weeks after the start of infiltration, a perchlorate spike of 72,400 µg/L was detected below the gallery. The increase in perchlorate

[Effects of perchlorate on growth and chlorophyll fluorescence parameters of Alternanthera philoxeroides].

PubMed

Xie, Yin-feng; Cai, Xian-lei; Liu, Wei-long; Deng, Wei

2009-08-15

Perchlorate is a new emerging persistent pollutant, while no studies about its effects on plants have been reported both home and abroad. In order to explore the effects of perchlorate on growth and physiology of aquatic plant, Alternanthera philoxeroides were treated by 1/20 Hoagland nutrient solution with different concentrations (0, 1, 5, 20, 100, 500 mg/L) of ClO4- under the controlled conditions. The results showed as follow. (1) Under perchlorate treatment, relative growth yield,dry weight of root,shoot and leaves were inhibited at different degrees, in which root biomass under different treatments showed significant difference to the control. After treatment for 40 d, relative growth yield of different treatments at concentration from 1 mg/L to 500 mg/L were about 61.6%, 60.8%, 53.1%, 20.4% and 3.3% separately of the control. And the order of variation coefficients of biomass in different organ were as follows: leaf > root biomass > stem; the relationship of biomass allocation in different organs of Alternanthera philoxeroides under perchlorate treatment changed, and the proportion of stem biomass increased,while leaf decreased, in which 100 and 500 mg/L ClO4- treatment showed significant difference to the control. (2) Under perchlorate treatment, young leaves of Alternanthera philoxeroides presented injury symptoms (such as parietal roiling reversely, leaf edge getting black and withered etc), and the damaged degree of Alternanthera philoxeroides increased with the increase of treatment concentration and time. (3) Under perchlorate treatment, the relative chlorophyll content (SPAD value), primary maximal PSII efficiency(Fv/Fm), efficiency of excitation capture by open PSII centre (F'v,/F'm), actual photochemical efficiency of PSII (phi(PS II)), electron transport rate (ETR), maximal electron transport rate(ETR ,) and other indexes were inhibited at different degrees. SPAD and chlorophyll fluorescence parameters (phi(PS II)) etc. could be used as sensitive

Chlorine Isotopic Composition of Perchlorate in Human Urine as a Means of Distinguishing Among Natural and Synthetic Exposure Sources

PubMed Central

Poghosyan, Armen; Morel-Espinosa, Maria; Valentín-Blasini, Liza; Blount, Benjamin C.; Ferreccio, Catterina; Steinmaus, Craig M.; Sturchio, Neil C.

2015-01-01

Perchlorate (ClO4−) is a ubiquitous environmental contaminant with high human exposure potential; it has both natural and man-made sources in the environment. Natural perchlorate forms in the atmosphere from where it deposits onto the surface of Earth, whereas synthetic perchlorate is manufactured as an oxidant for industrial, aerospace, and military applications. Perchlorate exposure can potentially cause adverse health effects in humans by interfering with the production of thyroid hormones through competitively blocking iodide uptake. To control and reduce perchlorate exposure, the contributions of different sources of perchlorate exposure need to be quantified. Thus, we demonstrate a novel approach for determining the contribution of different perchlorate exposure sources by quantifying stable and radioactive chlorine isotopes of perchlorate extracted from composite urine samples from two distinct populations: one in Atlanta, USA and one in Taltal, Chile (Atacama region). Urinary perchlorate from the Atlanta region resembles indigenous natural perchlorate from the southwestern USA [δ37Cl = +4.1 ± 1.0 ‰; 36Cl/Cl = 1811 (± 136) × 10−15], and urinary perchlorate from the Taltal, Chile region is similar to natural perchlorate in nitrate salt deposits from the Atacama Desert of northern Chile [δ37Cl = −11.0 ± 1.0 ‰; 36Cl/Cl = 254 (± 40) × 10−15]. Neither urinary perchlorate resembled the isotopic pattern found in synthetic perchlorate. These results indicate that natural perchlorate of regional provenance is the dominant exposure source for the two sample populations, and that chlorine isotope ratios provide a robust tool for elucidating perchlorate exposure pathways. PMID:25805252

Electrochemical Behaviour and Electrorefining of Cobalt in NaCl-KCl-K2TiF6 Melt

NASA Astrophysics Data System (ADS)

Kuznetsov, Sergey A.; Kazakova, Olga S.; Makarova, Olga V.

2009-08-01

The electrorefining of cobalt in NaCl-KCl-K2TiF6 (20 wt%) melt has been investigated. It was shown that complexes of Ti(III) and Co(II) appeared in the melt due to the reaction 2Ti(IV) + Co → 2Ti(III) + Co(II) and this reaction was entirely shifted to the right hand side. On the base of linear sweep voltammetry diagnostic criteria it was found that the discharge of Co(II) to Co metal is controlled by diffusion. The limiting current density of discharge Co(II) to metal in NaCl-KCl-K2TiF6 (20 wt%) melt was determined by steady-state voltammetry. The electrorefining of cobalt was carried out in hermetic electrolyser under argon atmosphere. Initial cathodic current density was changed from 0.2 Acm-2 up to 0.7 Acm-2, the electrolysis temperature varied within 973 - 1123 K. Behaviour of impurities during cobalt electrorefining was discussed. It was shown that electrorefining led to the elimination of most of the interstitial impurities (H2, N2, O2, C), with the result that the remaining impurity levels below 10 ppm impart high ductility to cobalt.

Occurrence of perchlorate in groundwater, paired farmland soil, lettuce, and rhizosphere soil from Chengdu, China.

PubMed

Tang, Yulu; Zhong, Bifeng; Qu, Bing; Feng, Shujin; Ding, Sanglan; Su, Shijun; Li, Zhi; Gan, Zhiwei

2017-05-24

A total of 28 groundwater, paired farmland soil, lettuce, and its rhizosphere soil samples were collected from Chengdu, China to detect perchlorate levels and to evaluate the relationships of perchlorate concentrations among these matrices. The perchlorate concentrations in the groundwater, farmland soil, lettuce, and rhizosphere soil samples ranged from below detection limit to 60.2 μg L -1 , from below detection limit to 249 μg kg -1 dry weight (dw), from 2.07 to 1010 μg kg -1 wet weight, and from below detection limit to 314 μg kg -1 dw, respectively. Significant correlation was found in the perchlorate levels among the farmland soil, lettuce, and rhizosphere soil, suggesting that they have common pollution sources, or perchlorate might transfer from farmland soil-rhizosphere soil-plant. However, there is no significant correlation between groundwater and the other three matrices, indicating that infiltration from perchlorate contaminated farmland soil was not the predominant source for groundwater pollution in Chengdu. The perchlorate concentrations in the farmland soil and lettuce samples were significantly higher than those in the rhizosphere soil, primarily due to uptake of perchlorate through the rhizosphere micro-environment by lettuce, or accelerated degradation by rhizospheric microorganisms, which contributed more needs further investigation.

Monitoring of perchlorate in diverse foods and its estimated dietary exposure for Korea populations.

PubMed

Lee, Ji-Woo; Oh, Sung-Hee; Oh, Jeong-Eun

2012-12-01

The perchlorate concentrations in various Korean food samples were monitored, and 663 samples belonging to 39 kinds of food were analyzed. The analysis results revealed that dairy products contain the highest average concentration of 6.34 μg/kg and high detection frequency of over 85%. Fruit and vegetables showed the next highest perchlorate concentration with an average of 6.17 μg/kg. Especially, with its average concentration of 39.9 μg/kg, spinach showed the highest perchlorate level among all target food samples studied. Tomato was followed by spinach, which showed a high perchlorate average concentration of 19.8 μg/kg, and over 7 μg/kg was detected in ham and sausage (avg. 7.31 μg/kg) and in instant noodles (avg. 7.58 μg/kg). Less than 2 μg/kg was detected in fishes, meats and beverages. The exposure dose of perchlorate in Korean by food intake was calculated on the basis of the analyzed perchlorate levels in this study. The daily perchlorate dose to which Korean adults are exposed is 0.04 μg/kg bw/day, which is lower than the RfD (0.7 μg/kg bw/day) value suggested by US NAS. This result indicates that Korean people's current exposure to perchlorate from domestic food consumption is evaluated as safe. Copyright © 2012 Elsevier B.V. All rights reserved.

ASSESSMENT OF PERCHLORATE IN FERTILIZERS

EPA Science Inventory

Perchlorate has been positively detected only in those materials known to be derived from Chilean caliche, which constitute less than 0.2% of U.S. fertilizer application. The data obtained in the preponderance of investigations suggest that fertilizers do not contribute to envir...

Occurrence of perchlorate in drinking water and seawater in South Korea.

PubMed

Her, Namguk; Jeong, Hyunchan; Kim, Jongsung; Yoon, Yeomin

2011-08-01

Concentrations of perchlorate were determined by both liquid-chromatography-mass spectrometry (LC-MS) and ion chromatography tandem mass spectrometry (IC-MS/MS) in 520 tap-water, 48 bottled-water, and 9 seawater samples obtained or purchased from >100 different locations in South Korea. The method detection limits were 0.013 μg/L for LC-MS and 0.005 μg/L for IC-MS/MS, and the limits of quantification (LOQs) were 0.10 μg/L for LC-MS and 0.032 μg/L for IC-MS/MS. Perchlorate was detected in most (80%) of the tap-water samples, with concentrations higher than the LOQ; the concentrations ranged from <1.0 to 6.1 μg/L (mean 0.56). Perchlorate was detected by IC-MS/MS in many (n = 23) of the bottled-water samples, with concentrations higher then the LOQ, ranging from 0.04 to 0.29 μg/L (mean 0.07 ± 0.01). The concentrations of perchlorate in all seawater samples collected from the various locations were higher than the LOQ, with a mean concentration of 1.15 ± 0.01 μg/L (maximum 6.11 and minimum 0.11). This study provides further evidence that drinking-water sources have been contaminated by perchlorate. To the best of our knowledge, this is the first comprehensive study on perchlorate assessment in drinking water and seawater in South Korea.

Blood doping by cobalt. Should we measure cobalt in athletes?

PubMed Central

Lippi, Giuseppe; Franchini, Massimo; Guidi, Gian Cesare

2006-01-01

Background Blood doping is commonplace in competitive athletes who seek to enhance their aerobic performances through illicit techniques. Presentation of the hypothesis Cobalt, a naturally-occurring element with properties similar to those of iron and nickel, induces a marked and stable polycythemic response through a more efficient transcription of the erythropoietin gene. Testing the hypothesis Although little information is available so far on cobalt metabolism, reference value ranges or supplementation in athletes, there is emerging evidence that cobalt is used as a supplement and increased serum concentrations are occasionally observed in athletes. Therefore, given the athlete's connatural inclination to experiment with innovative, unfair and potentially unhealthy doping techniques, cobalt administration might soon become the most suited complement or surrogate for erythropoiesis-stimulating substances. Nevertheless, cobalt administration is not free from unsafe consequences, which involve toxic effects on heart, liver, kidney, thyroid and cancer promotion. Implications of the hypothesis Cobalt is easily purchasable, inexpensive and not currently comprehended within the World Anti-Doping Agency prohibited list. Moreover, available techniques for measuring whole blood, serum, plasma or urinary cobalt involve analytic approaches which are currently not practical for antidoping laboratories. Thus more research on cobalt metabolism in athletes is compelling, along with implementation of effective strategies to unmask this potentially deleterious doping practice PMID:16863591

Mechanistic Studies on the Radiolytic Decomposition of Perchlorates on the Martian Surface

NASA Astrophysics Data System (ADS)

Turner, Andrew M.; Abplanalp, Matthew J.; Kaiser, Ralf I.

2016-04-01

Perchlorates—inorganic compounds carrying the perchlorate ion ({{ClO}}4{}-)—were discovered at the north polar landing site of the Phoenix spacecraft and at the southern equatorial landing site of the Curiosity Rover within the Martian soil at levels of 0.4-0.6 wt%. This study explores in laboratory experiments the temperature-dependent decomposition mechanisms of hydrated perchlorates—namely magnesium perchlorate hexahydrate (Mg(ClO4)2·6H2O)—and provides yields of the oxygen-bearing species formed in these processes at Mars-relevant surface temperatures from 165 to 310 K in the presence of galactic cosmic-ray particles (GCRs). Our experiments reveal that the response of the perchlorates to the energetic electrons is dictated by the destruction of the perchlorate ion ({{ClO}}4{}-) and the inherent formation of chlorates ({{ClO}}3{}-) plus atomic oxygen (O). Isotopic substitution experiments reveal that the oxygen is released solely from the perchlorate ion and not from the water of hydration (H2O). As the mass spectrometer detects only molecular oxygen (O2) and no atomic oxygen (O), atomic oxygen recombines to molecular oxygen within the perchlorates, with the overall yield of molecular oxygen increasing as the temperature drops from 260 to 160 K. Absolute destruction rates and formation yields of oxygen are provided for the planetary modeling community.

Evaluation of the coordination preferences and catalytic pathways of heteroaxial cobalt oximes towards hydrogen generation

DOE PAGES

Basu, Debashis; Mazumder, Shivnath; Niklas, Jens; ...

2016-02-02

Three new heteroaxial cobalt oxime catalysts, namely [Co III(prdioxH)( 4tBupy)(Cl)]PF 6 (1), [Co III(prdioxH)( 4Pyrpy)(Cl)]PF 6 (2), and [Co III(prdioxH)( 4Bzpy)(Cl)]PF 6 (3) have been studied. These species contain chloro and substituted tert-butyl/pyrrolidine/benzoyl-pyridino ligands axially coordinated to a trivalent cobalt ion bound to the N 4-oxime macrocycle (2 E,2' E,3 E,3' E)-3,3'-(propane-1,3-diylbis(azanylylidene))bis(butan-2-one)dioxime, abbreviated (prdioxH)– in its monoprotonated form. Emphasis was given to the spectroscopic investigation of the coordination preferences and spin configurations among the different 3d 6 Co III, 3d 7 Co II, and 3d 8 Co I oxidation states of the metal, and to the catalytic proton reduction withmore » an evaluation of the pathways for the generation of H 2 via Co III–H – or Co II–H – intermediates by mono and bimetallic routes. The strong field imposed by the (prdioxH)– ligand precludes the existence of high-spin configurations, and 6-coordinate geometry is favored by the LSCo III species. Species 1 and 3 show a split Co III/Co II electrochemical wave associated with partial chemical conversion to a [Co III(prdioxH)Cl 2] species, whereas 2 shows a single event. The reduction of these Co III complexes yields LSCo II and LSCo I species in which the pyridine acts as the dominant axial ligand. In the presence of protons, the catalytically active Co I species generates a Co III–H – hydride species that reacts heterolytically with another proton to generate dihydrogen. The intermediacy of a trifluoroacetate-bound Co III/Co II couple in the catalytic mechanism is proposed. Finally, these results allow for a generalization of the behavior of heteroaxial cobalt macrocycles and serve as guidelines for the development of new catalysts based on macrocyclic frameworks.« less

Bacterial growth tolerance to concentrations of chlorate and perchlorate salts relevant to Mars

NASA Astrophysics Data System (ADS)

Al Soudi, Amer F.; Farhat, Omar; Chen, Fei; Clark, Benton C.; Schneegurt, Mark A.

2017-07-01

The Phoenix lander at Mars polar cap found appreciable levels of (per)chlorate salts, a mixture of perchlorate and chlorate salts of Ca, Fe, Mg and Na at levels of ~0.6% in regolith. These salts are highly hygroscopic and can form saturated brines through deliquescence, likely producing aqueous solutions with very low freezing points on Mars. To support planetary protection efforts, we have measured bacterial growth tolerance to (per)chlorate salts. Existing bacterial isolates from the Great Salt Plains of Oklahoma (NaCl-rich) and Hot Lake in Washington (MgSO4-rich) were tested in high concentrations of Mg, K and Na salts of chlorate and perchlorate. Strong growth was observed with nearly all of these salinotolerant isolates at 1% (~0.1 M) (per)chlorate salts, similar to concentrations observed in bulk soils on Mars. Growth in perchlorate salts was observed at concentrations of at least 10% (~1.0 M). Greater tolerance was observed for chlorate salts, where growth was observed to 2.75 M (>25%). Tolerance to K salts was greatest, followed by Mg salts and then Na salts. Tolerances varied among isolates, even among those within the same phylogenetic clade. Tolerant bacteria included genera that also are found in spacecraft assembly facilities. Substantial microbial tolerance to (per)chlorate salts is a concern for planetary protection since tolerant microbes contaminating spacecraft would have a greater chance for survival and proliferation, despite the harsh chemical conditions found near the surface of Mars.

Thyroid hormones and thyroid disease in relation to perchlorate dose and residence near a superfund site.

PubMed

Gold, Ellen B; Blount, Benjamin C; O'Neill Rasor, Marianne; Lee, Jennifer S; Alwis, Udeni; Srivastav, Anup; Kim, Kyoungmi

2013-07-01

Perchlorate is a widely occurring contaminant, which can competitively inhibit iodide uptake and thus thyroid hormone production. The health effects of chronic low dose perchlorate exposure are largely unknown. In a community-based study, we compared thyroid function and disease in women with differing likelihoods of prior and current perchlorate exposure. Residential blocks were randomly selected from areas: (1) with potential perchlorate exposure via drinking water; (2) with potential exposure to environmental contaminants; and (3) neighboring but without such exposures. Eligibility included having lived in the area for ≥6 months and aged 20-50 years during 1988-1996 (during documented drinking water well contamination). We interviewed 814 women and collected blood samples (assayed for thyroid stimulating hormone and free thyroxine) from 431 interviewed women. Daily urine samples were assayed for perchlorate and iodide for 178 premenopausal women with blood samples. We performed multivariable regression analyses comparing thyroid function and disease by residential area and by urinary perchlorate dose adjusted for urinary iodide levels. Residential location and current perchlorate dose were not associated with thyroid function or disease. No persistent effect of perchlorate on thyroid function or disease was found several years after contaminated wells were capped.

Perchlorate Contamination of Drinking Water: Regulatory Issues and Legislative Actions

DTIC Science & Technology

2008-10-16

and water treatment costs, both of which are driven by federal and state standards. (California and Massachusetts have set standards.) EPA has spent... Hypothyroidism , Newborn Thyroid Function, and Environmental Perchlorate Exposure Among Residents of a Southern California Community,” Journal of Occupational... treatment technologies and for collecting occurrence data. In 1999, EPA required water systems to monitor for perchlorate under the Unregulated

Mechanistic Studies of Cobalt-Catalyzed C(sp2)-H Borylation of Five-Membered Heteroarenes with Pinacolborane.

PubMed

Obligacion, Jennifer V; Chirik, Paul J

2017-07-07

Studies into the mechanism of cobalt-catalyzed C(sp 2 )-H borylation of five-membered heteroarenes with pinacolborane (HBPin) as the boron source established the catalyst resting state as the trans -cobalt(III) dihydride boryl, ( iPr PNP)Co(H) 2 (BPin) ( iPr PNP = 2,6-( i Pr 2 PCH 2 ) 2 (C 5 H 3 N)), at both low and high substrate conversions. The overall first-order rate law and observation of a normal deuterium kinetic isotope effect on the borylation of benzofuran versus benzofuran-2- d 1 support H 2 reductive elimination from the cobalt(III) dihydride boryl as the turnover-limiting step. These findings stand in contrast to that established previously for the borylation of 2,6-lutidine with the same cobalt precatalyst, where borylation of the 4-position of the pincer occurred faster than the substrate turnover and arene C-H activation by a cobalt(I) boryl is turnover-limiting. Evaluation of the catalytic activity of different cobalt precursors in the C-H borylation of benzofuran with HBPin established that the ligand design principles for C- H borylation depend on the identities of both the arene and the boron reagent used: electron-donating groups improve catalytic activity of the borylation of pyridines and arenes with B 2 Pin 2 , whereas electron-withdrawing groups improve catalytic activity of the borylation of five-membered heteroarenes with HBPin. Catalyst deactivation by P-C bond cleavage from a cobalt(I) hydride was observed in the C-H borylation of arene substrates with C-H bonds that are less acidic than those of five-membered heteroarenes using HBPin and explains the requirement of B 2 Pin 2 to achieve synthetically useful yields with these arene substrates.

Particle size distribution and perchlorate levels in settled dust from urban roads, parks, and roofs in Chengdu, China.

PubMed

Li, Yiwen; Shen, Yang; Pi, Lu; Hu, Wenli; Chen, Mengqin; Luo, Yan; Li, Zhi; Su, Shijun; Ding, Sanglan; Gan, Zhiwei

2016-01-01

A total of 27 settled dust samples were collected from urban roads, parks, and roofs in Chengdu, China to investigate particle size distribution and perchlorate levels in different size fractions. Briefly, fine particle size fractions (<250 μm) were the dominant composition in the settled dust samples, with mean percentages of 80.2%, 69.5%, and 77.2% for the urban roads, roofs, and the parks, respectively. Perchlorate was detected in all of the size-fractionated dust samples, with concentrations ranging from 73.0 to 6160 ng g(-1), and the median perchlorate levels increased with decreasing particle size. The perchlorate level in the finest fraction (<63 μm) was significantly higher than those in the coarser fractions. To our knowledge, this is the first report on perchlorate concentrations in different particle size fractions. The calculated perchlorate loadings revealed that perchlorate was mainly associated with finer particles (<125 μm). An exposure assessment indicated that exposure to perchlorate via settled road dust intake is safe to both children and adults in Chengdu, China. However, due to perchlorate mainly existing in fine particles, there is a potential for perchlorate to transfer into surface water and the atmosphere by runoff and wind erosion or traffic emission, and this could act as an important perchlorate pollution source for the indoor environment, and merits further study.

Developmental Exposure to Perchlorate Alters Synaptic Transmission in Hippocampus of the Adult Rat

PubMed Central

Gilbert, Mary E.; Sui, Li

2008-01-01

Background Perchlorate is an environmental contaminant that blocks iodine uptake into the thyroid gland and reduces thyroid hormones. This action of perchlorate raises significant concern over its effects on brain development. Objectives The purpose of this study was to evaluate neurologic function in rats after developmental exposure to perchlorate. Methods Pregnant rats were exposed to 0, 30, 300, or 1,000 ppm perchlorate in drinking water from gestational day 6 until weaning. Adult male offspring were evaluated on a series of behavioral tasks and neurophysiologic measures of synaptic function in the hippocampus. Results At the highest perchlorate dose, triiodothyronine (T3) and thyroxine (T4) were reduced in pups on postnatal day 21. T4 in dams was reduced relative to controls by 16%, 28%, and 60% in the 30-, 300-, and 1,000-ppm dose groups, respectively. Reductions in T4 were associated with increases in thyroid-stimulating hormone in the high-dose group. No changes were seen in serum T3. Perchlorate did not impair motor activity, spatial learning, or fear conditioning. However, significant reductions in baseline synaptic transmission were observed in hippocampal field potentials at all dose levels. Reductions in inhibitory function were evident at 300 and 1,000 ppm, and augmentations in long-term potentiation were observed in the population spike measure at the highest dose. Conclusions Dose-dependent deficits in hippocampal synaptic function were detectable with relatively minor perturbations of the thyroid axis, indicative of an irreversible impairment in synaptic transmission in response to developmental exposure to perchlorate. PMID:18560531

Mechanisms of direct inhibition of the respiratory sulfate-reduction pathway by (per)chlorate and nitrate.

PubMed

Carlson, Hans K; Kuehl, Jennifer V; Hazra, Amrita B; Justice, Nicholas B; Stoeva, Magdalena K; Sczesnak, Andrew; Mullan, Mark R; Iavarone, Anthony T; Engelbrektson, Anna; Price, Morgan N; Deutschbauer, Adam M; Arkin, Adam P; Coates, John D

2015-06-01

We investigated perchlorate (ClO(4)(-)) and chlorate (ClO(3)(-)) (collectively (per)chlorate) in comparison with nitrate as potential inhibitors of sulfide (H(2)S) production by mesophilic sulfate-reducing microorganisms (SRMs). We demonstrate the specificity and potency of (per)chlorate as direct SRM inhibitors in both pure cultures and undefined sulfidogenic communities. We demonstrate that (per)chlorate and nitrate are antagonistic inhibitors and resistance is cross-inducible implying that these compounds share at least one common mechanism of resistance. Using tagged-transposon pools we identified genes responsible for sensitivity and resistance in Desulfovibrio alaskensis G20. We found that mutants in Dde_2702 (Rex), a repressor of the central sulfate-reduction pathway were resistant to both (per)chlorate and nitrate. In general, Rex derepresses its regulon in response to increasing intracellular NADH:NAD(+) ratios. In cells in which respiratory sulfate reduction is inhibited, NADH:NAD(+) ratios should increase leading to derepression of the sulfate-reduction pathway. In support of this, in (per)chlorate or nitrate-stressed wild-type G20 we observed higher NADH:NAD(+) ratios, increased transcripts and increased peptide counts for genes in the core Rex regulon. We conclude that one mode of (per)chlorate and nitrate toxicity is as direct inhibitors of the central sulfate-reduction pathway. Our results demonstrate that (per)chlorate are more potent inhibitors than nitrate in both pure cultures and communities, implying that they represent an attractive alternative for controlling sulfidogenesis in industrial ecosystems. Of these, perchlorate offers better application logistics because of its inhibitory potency, solubility, relative chemical stability, low affinity for mineral cations and high mobility in environmental systems.

DEVELOPMENT OF AN ELECTROSPRAY MASS SPECTROMETRIC METHOD FOR DETERMINING PERCHLORATE IN FERTILIZERS

EPA Science Inventory

An electrospray mass spectrometric method has been developed for application to agricultural and horticultural fertilizers to determine perchlorate. After fertilizers are leached or dissolved in water, the method relies on the formation of stable ion pair complex of the perchlor...

Thyroid Hormones and Thyroid Disease in Relation to Perchlorate Dose and Residence Near a Superfund Site

PubMed Central

Gold, Ellen B.; Blount, Benjamin C.; Rasor, Marianne O’Neill; Lee, Jennifer S.; Alwis, Udeni; Srivastav, Anup; Kim, Kyoungmi

2013-01-01

Background Perchlorate is a widely occurring contaminant, which can competitively inhibit iodide uptake and thus thyroid hormone production. The health effects of chronic low dose perchlorate exposure are largely unknown. Objectives In a community-based study, we compared thyroid function and disease in women with differing likelihoods of prior and current perchlorate exposure. Methods Residential blocks were randomly selected from areas: 1) with potential perchlorate exposure via drinking water; 2) with potential exposure to environmental contaminants; and 3) neighboring but without such exposures. Eligibility included having lived in the area for ≥6 months and aged 20–50 years during 1988–1996 (during documented drinking water well contamination). We interviewed 814 women and collected blood samples (assayed for thyroid stimulating hormone [TSH] and free thyroxine [fT4]) from 431 interviewed women. Daily urine samples were assayed for perchlorate and iodide for 178 premenopausal women with blood samples. We performed multivariable regression analyses comparing thyroid function and disease by residential area and by urinary perchlorate dose adjusted for urinary iodide levels. Results Residential location and current perchlorate dose were not associated with thyroid function or disease. Conclusions No persistent effect of perchlorate on thyroid function or disease was found several years after contaminated wells were capped. PMID:22968349

Effect of nitrate, acetate and hydrogen on native perchlorate-reducing microbial communities and their activity in vadose soil

PubMed Central

Nozawa-Inoue, Mamie; Jien, Mercy; Yang, Kun; Rolston, Dennis E.; Hristova, Krassimira R.; Scow, Kate M.

2011-01-01

Effect of nitrate, acetate and hydrogen on native perchlorate-reducing bacteria (PRB) was examined by conducting microcosm tests using vadose soil collected from a perchlorate-contaminated site. The rate of perchlorate reduction was enhanced by hydrogen amendment and inhibited by acetate amendment, compared to unamendment. Nitrate was reduced before perchlorate in all amendments. In hydrogen-amended and unamended soils, nitrate delayed perchlorate reduction, suggesting the PRB preferentially use nitrate as an electron acceptor. In contrast, nitrate eliminated the inhibitory effect of acetate amendment on perchlorate reduction and increased the rate and the extent, possibly because the preceding nitrate reduction/denitrification decreased the acetate concentration which was inhibitory to the native PRB. In hydrogen-amended and unamended soils, perchlorate reductase gene (pcrA) copies, representing PRB densities, increased with either perchlorate or nitrate reduction, suggesting either perchlorate or nitrate stimulates growth of the PRB. In contrast, in acetate-amended soil pcrA increased only when perchlorate was depleted: a large portion of the PRB may have not utilized nitrate in this amendment. Nitrate addition did not alter the distribution of the dominant pcrA clones in hydrogen-amended soil, likely because of the functional redundancy of PRB as nitrate-reducers/denitrifiers, whereas acetate selected different pcrA clones from those with hydrogen amendment. PMID:21284679

40 CFR 721.10599 - Calcium cobalt lead titanium tungsten oxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... systems). (iii) Release to water. Requirements as specified in § 721.90 (a)(4), (b)(4), and (c)(4) (Where N=8, and 8 is an aggregate of releases for the following substances: Lead strontium titanium...-271; CAS No. 1262279-31-1); Calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS...

40 CFR 721.10599 - Calcium cobalt lead titanium tungsten oxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... systems). (iii) Release to water. Requirements as specified in § 721.90 (a)(4), (b)(4), and (c)(4) (Where N=8, and 8 is an aggregate of releases for the following substances: Lead strontium titanium...-271; CAS No. 1262279-31-1); Calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS...

Using a physiologically based pharmacokinetic model to link urinary biomarker concentrations to dietary exposure of perchlorate

EPA Science Inventory

Exposure to perchlorate is widespread in the United States and many studies have attempted to character the perchlorate exposure by estimating the average daily intakes of perchlorate. These approaches provided population-based estimates, but did not provide individual-level exp...

Perchlorate disrupts embryonic androgen synthesis and reproductive development in threespine stickleback without changing whole-body levels of thyroid hormone

PubMed Central

Petersen, Ann M.; Dillon, Danielle; Bernhardt, Richard A.; Torunsky, Roberta; Postlethwait, John H.; von Hippel, Frank A.; Buck, C. Loren; Cresko, William A.

2014-01-01

Perchlorate, an environmental contaminant, disrupts normal functioning of the thyroid. We previously showed that perchlorate disrupts behavior and gonad development, and induces external morphological changes in a vertebrate model organism, the threespine stickleback. Whether perchlorate alters these phenotypes via a thyroid-mediated mechanism, and the extent to which the effects depend on dose, are unknown. To address these questions, we chronically exposed stickleback to control conditions and to three concentrations of perchlorate (10, 30 and 100 ppm) at various developmental stages from fertilization to reproductive maturity. Adults chronically exposed to perchlorate had increased numbers of thyroid follicles and decreased numbers of thyrocytes. Surprisingly, T4 and T3 levels in larval, juvenile, and adult whole fish chronically exposed to perchlorate did not differ from controls, except at the lowest perchlorate dose, suggesting a non-monotonic dose response curve. We found no detectable abnormalities in external phenotype at any dose of perchlorate, indicating that the increased number of thyroid follicles compensated for the disruptive effects of these doses. In contrast to external morphology, gonadal development was altered substantially, with the highest dose of perchlorate causing the largest effects. Perchlorate increased the number both of early stage ovarian follicles in females and of advanced spermatogenic stages in males. Perchlorate also disrupted embryonic androgen levels. We conclude that chronic perchlorate exposure may not result in lasting adult gross morphological changes but can produce lasting modifications to gonads when compensation of T3 and T4 levels occurs by thyroid follicle hyperplasia. Perchlorate may therefore affect vertebrate development via both thyroidal and non-thyroidal mechanisms. PMID:25448260

A survey on the temporal and spatial distribution of perchlorate in the Potomac River.

PubMed

Impellitteri, Christopher A; Saxe, Jennie P; Schmitt, Ellen C; Young, K R

2011-08-01

Samples of river water and treated drinking water were obtained from eight sites along the Potomac River between western Maryland and Washington DC. Samples were collected each month from October 2007 to September 2008 and analyzed for perchlorate by ion chromatography/mass spectrometry. Data on anions were also collected for seven of the twelve months. Data were analyzed to identify spatial and temporal patterns for the occurrence of perchlorate in the Potomac. Over the year of sampling, the largest monthly increase occurred from June to July, with levels then decreasing from July to September. Samples from the period between December and May had lower perchlorate concentrations, relative to the remainder of the study year. Spatially, higher levels of perchlorate were found at sites located in west-central Maryland, the eastern panhandle of West Virginia, and central northern Virginia, with levels decreasing slightly as the Potomac approaches Washington DC. Within the sampling boundaries, river (untreated) water perchlorate concentrations ranged from 0.03 μg L(-1) to 7.63 μg L(-1), averaged 0.67 ± 0.97 μg L(-1) over the year-long period and had a median value of 0.37 μg L(-1). There was no evidence that any of the existing drinking water treatment technologies at the sampling sites were effective in removing perchlorate. There were no correlations found between the presence of perchlorate and any of the anions or water quality parameters examined in the source water with the exception of a weak positive correlation with water temperature. Results from the summer (June-August) and fall (September-November) months sampled in this study were generally higher than from the winter and spring months (December-May). All but one of the locations had annual average perchlorate levels below 1 μg L(-1); however, 7 of the 8 sites sampled had river water perchlorate detections over 1 μg L(-1) and 5 of the 8 sites had treated water detections over this level.

Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.

PubMed

Amitai, Yona; Winston, Gary; Sack, Joseph; Wasser, Janice; Lewis, Matthew; Blount, Benjamin C; Valentin-Blasini, Liza; Fisher, Nirah; Israeli, Avi; Leventhal, Alex

2007-09-01

To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)). T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate < or = 340 microg/L (very high exposure, n = 97), 42-94 microg/L (high exposure, n = 216), and < 3 microg/L (low exposure, n = 843). In the very high and high exposure areas, T(4) values in newborns whose mothers drank tap water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure. Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls. This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.

77 FR 52633 - Notice of a Public Meeting: Stakeholder Meeting Concerning EPA's Intent To Regulate Perchlorate...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-30

...: Stakeholder Meeting Concerning EPA's Intent To Regulate Perchlorate Levels in Drinking Water AGENCY... a proposed National Primary Drinking Water Regulation for Perchlorate. DATES: The public meeting and... to obtain access to the building. FOR FURTHER INFORMATION CONTACT: More information on Perchlorate is...

77 FR 64335 - Notification of a Public Teleconference of the Science Advisory Board; Perchlorate Advisory Panel

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-19

... Science Advisory Board; Perchlorate Advisory Panel AGENCY: Environmental Protection Agency (EPA). ACTION... announces two public teleconferences of the SAB Perchlorate Advisory Panel to discuss its revised draft... Epidemiological Evidence to Develop a Maximum Contaminant Level Goal (MCLG) for Perchlorate. DATES: The public...

On the cobalt and cobalt oxide electrodeposition from a glyceline deep eutectic solvent.

PubMed

Sakita, Alan M P; Della Noce, Rodrigo; Fugivara, Cecílio S; Benedetti, Assis V

2016-09-14

The electrodeposition of cobalt and cobalt oxides from a glyceline deep eutectic solvent is reported. Cyclic voltammetry, chronoamperometry, scanning electron microscopy, and Raman spectroscopy are employed to study the Co deposition processes. Surface analysis reveals that metallic cobalt is deposited at potentials less negative than the current peak potential whereas cobalt oxides are detected and electrochemically observed when the deposition is done at more negative potentials. i-t transients are analyzed by applying the Scharifker and Hills (SH) theoretical model. It is concluded that cobalt deposition occurs via a progressive nucleation and growth mechanism for concentrations higher than 0.05 mol L -1 cobalt ions. For concentrations ≤0.025 mol L -1 cobalt ions and low overpotentials, the mechanism changes to instantaneous nucleation. The i m -t m relationships of the SH model are used to determine the values of the kinetic parameters and the cobalt ion diffusion coefficient.

Urinary perchlorate exposure and risk in women of reproductive age in a fireworks production area of China.

PubMed

Li, Qin; Yu, Yun-jiang; Wang, Fei-fei; Chen, Shi-wu; Yin, Yan; Lin, Hai-peng; Che, Fei; Sun, Peng; Qin, Juan; Liu, Jie; Wang, Hong-mei

2014-07-01

Perchlorate is used widely in fireworks, and, if ingested, it has the potential to disrupt thyroid function. The concentrations of perchlorate in water and soil samples and in urine samples of women of reproductive age from Liuyang, the largest fireworks production area in China, were investigated. The results showed that the average perchlorate concentrations in groundwater, surface water, farmland soil, and urine samples of women from the fireworks production area were significantly greater than those from the control area. The health risk of perchlorate ingested through drinking water was assessed based on the mode recommended by the United States Environmental Protection Agency. The values of hazard quotient of river water and groundwater in the fireworks production area were much greater than the safe level (=1), which indicates that adverse health effects may result from perchlorate when these sources of water are used as drinking water. These results indicated that the environment of the fireworks production area has been polluted by perchlorate and that residents were and are facing greater exposure doses of perchlorate. Fireworks production enterprises may be a major source of perchlorate contamination.

Effects of larval-juvenile treatment with perchlorate and co-treatment with thyroxine on zebrafish sex ratios

USGS Publications Warehouse

Mukhi, S.; Torres, L.; Patino, R.

2007-01-01

The objective of this study was to determine the effect of larval-juvenile exposure to perchlorate, a thyroid hormone synthesis inhibitor, on the establishment of gonadal sex ratios in zebrafish. Zebrafish were exposed to untreated water or water containing perchlorate at 100 or 250 ppm for a period of 30 days starting at 3 days postfertilization (dpf). Recovery treatments consisted of a combination of perchlorate and exogenous thyroxine (T4; 10 nM). Thyroid histology was assessed at the end of the treatment period (33 dpf), and gonadal histology and sex ratios were determined in fish that were allowed an additional 10-day period of growth in untreated water. As expected, exposure to perchlorate caused changes in thyroid histology consistent with hypothyroidism and these effects were reversed by co-treatment with exogenous T4. Perchlorate did not affect fish survival but co-treatment with T4 induced higher mortality. However, relative to the corresponding perchlorate concentration, co-treatment with T4 caused increased mortality only at a perchlorate concentration of 100 ppm. Perchlorate alone or in the presence of T4 suppressed body length at 43 dpf relative to control values. Perchlorate exposure skewed the sex ratio toward female in a concentration-dependent manner, and co-treatment with T4 not only blocked the feminizing effect of perchlorate but also overcompensated by skewing the sex ratio towards male. Moreover, co-treatment with T4 advanced the onset of spermatogenesis in males. There was no clear association between sex ratios and larval survival or growth. We conclude that endogenous thyroid hormone plays a role in the establishment of gonadal sex phenotype during early development in zebrafish. ?? 2006 Elsevier Inc. All rights reserved.

METHOD DEVELOPMENT FOR THE LOW-LEVEL DETERMINATION OF PERCHLORATE IN DRINKING WATER

EPA Science Inventory

Perchlorate anion has been found in numerous drinking water supplies at concentrations that recent studies indicate may adversely affect human health. In order to measure perchlorate at levels of health concern in drinking water, there is a need to be able to quantify perchlorat...

PERCHLORATE ENVIRONMENTAL CONTAMINATION: TOXICOLOGICAL REVIEW AND RISK CHARACTERIZATION (EXTERNAL REVIEW DRAFT) 2002

EPA Science Inventory

Perchlorate (ClO4-) is an anion that originates as a contaminant in ground water and surface waters when the salts of ammonium, potassium, magnesium, or sodium dissolve in water. One major source of contamination is the manufacture or improper disposal of ammonium perchlorate th...

Cobalt release from inexpensive jewellery: has the use of cobalt replaced nickel following regulatory intervention?

PubMed

Thyssen, Jacob Pontoppidan; Jellesen, Morten S; Menné, Torkil; Lidén, Carola; Julander, Anneli; Møller, Per; Johansen, Jeanne Duus

2010-08-01

Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure. The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. The cobalt spot test was used to assess cobalt release from all items. Microstructural characterization was made using scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS). Cobalt release was found in 4 (1.1%) of 354 items. All these had a dark appearance. SEM/EDS was performed on the four dark appearing items which showed tin-cobalt plating on these. This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future. Industries may not be fully aware of the potential cobalt allergy problem.

Seasonal Variation and Exposure Risks of Perchlorate in Soil, Indoor Dust, and Outdoor Dust in China.

PubMed

Li, Yiwen; Liao, Ruoying; Gan, Zhiwei; Qu, Bing; Wang, Rong; Chen, Mengqin; Ding, Sanglan; Su, Shijun

2018-04-25

A total of 97 paired soil, outdoor dust, and indoor dust samples were collected in the national scale of China in summer, and the perchlorate levels were compared with those in soil and outdoor dust samples collected in winter in our previous study. The median perchlorate concentrations in the outdoor dust, indoor dust, and soil samples were 8.10, 11.4, and 0.05 mg/kg, respectively, which were significantly lower than those in the winter samples due to the natural factors and human activities. No significant differences in perchlorate concentrations were found between Northern and Southern China in the dust samples, whereas the difference was obtained in the soil samples. In the terms of possible source, the perchlorate levels in the outdoor dust exhibited strong correlation with SO 4 2- (r 2  = 0.458**) and NO 3 - (r 2  = 0.389**), indicating part of perchlorate in outdoor environment was likely from atmospheric oxidative process in summer. The perchlorate, SO 4 2- , and Cl - levels in the indoor dust were significantly related to those in the outdoor dust, suggesting that outdoor contaminants might be an important source for indoor environment. Furthermore, the human exposure to perchlorate was under relatively safe state in China except for special sites or periods with high perchlorate levels. Dust made an unexpected contribution of 41.3% to the total daily perchlorate intake for children, whereas 2.46% for adults in China based on biomonitoring, which deserves more attention.

Transport and degradation of perchlorate in deep vadose zone: implications from direct observations during bioremediation treatment

NASA Astrophysics Data System (ADS)

Dahan, Ofer; Katz, Idan; Avishai, Lior; Ronen, Zeev

2017-08-01

An in situ bioremediation experiment of a deep vadose zone ( ˜ 40 m) contaminated with a high concentration of perchlorate (> 25 000 mg L-1) was conducted through a full-scale field operation. Favourable environmental conditions for microbiological reduction of perchlorate were sought by infiltrating an electron donor-enriched water solution using drip irrigation underlying an airtight sealing liner. A vadose zone monitoring system (VMS) was used for real-time tracking of the percolation process, the penetration depth of dissolved organic carbon (DOC), and the variation in perchlorate concentration across the entire soil depth. The experimental conditions for each infiltration event were adjusted according to insight gained from data obtained by the VMS in previous stages. Continuous monitoring of the vadose zone indicated that in the top 13 m of the cross section, perchlorate concentration is dramatically reduced from thousands of milligrams per litre to near-detection limits with a concurrent increase in chloride concentration. Nevertheless, in the deeper parts of the vadose zone (< 17 m), perchlorate concentration increased, suggesting its mobilization down through the cross section. Breakthrough of DOC and bromide at different depths across the unsaturated zone showed limited migration capacity of biologically consumable carbon and energy sources due to their enhanced biodegradation in the upper soil layers. Nevertheless, the increased DOC concentration with concurrent reduction in perchlorate and increase in the chloride-to-perchlorate ratio in the top 13 m indicate partial degradation of perchlorate in this zone. There was no evidence of improved degradation conditions in the deeper parts where the initial concentrations of perchlorate were significantly higher.

Perchlorate Contamination of Drinking Water: Regulatory Issues and Legislative Actions

DTIC Science & Technology

2005-02-23

health risks of perchlorate exposures include effects on the developing nervous systems and thyroid tumors, based on rat studies that observed benign...supplies nationwide. The regulation required monitoring by all water systems serving more than 10,000 persons and by a representative sample of smaller... systems . In 2004, EPA reported that perchlorate has been detected in public water systems in 24 states and Puerto Rico.4 The agency also reported

Reactions of atomic oxygen with the chlorate ion and the perchlorate ion

NASA Astrophysics Data System (ADS)

Anan'ev, Vladimir; Miklin, Mikhail; Kriger, Ludmila

2014-06-01

The reactions of the chlorate ion with atomic oxygen formed under photolysis of the nitrate ion introduced to potassium chlorate crystal by co-crystallization were studied by optical and infrared absorption spectroscopy. The perchlorate ion was found to form in solids as product of addition reaction of singlet atomic oxygen, formed under dissociation of the peroxynitrite ion - the product of isomerization of the excited nitrate ion. Triplet atomic oxygen does not react with the chlorate ion. The atomic oxygen formed under photolysis of the nitrate ion introduced to potassium perchlorate crystal by co-crystallization does not react with the perchlorate ion.

The Radar Effects of Perchlorate-Doped Ice in the Martian Polar Layered Deposits

NASA Astrophysics Data System (ADS)

Stillman, D.; Winebrenner, D. P.; Grimm, R. E.; Pathare, A.

2010-12-01

The presence of perchlorate in soil at near-polar latitudes on Mars suggests that dust in the ice of the North Polar Layered Deposits (NPLD) may introduce perchlorate impurities to that ice. Because eutectic temperatures of perchlorate salts range as low as 206 K (for magnesium perchlorate), perchlorate doping of NPLD ice may result in grain-scale liquid veins and softening of ice rheology at temperatures comparable to those computed for the base of the NPLD in the present climate. Any such softening would be important for understanding how processes including ice flow have shaped the NPLD. Observable consequences of such softening, or of the combination of perchlorate doping and temperatures that could cause softening, are thus similarly important. In particular, the dielectric properties of perchlorate-laden ice in a temperature gradient will change relatively rapidly at the point in the gradient near the eutectic temperature. Here we investigate the radar reflectivity of such a eutectic transition in ice with a model in which perchlorate concentration is constant and temperature varies linearly with depth in the ice. We have conducted measurements of the complex permittivity of Mg and Na perchlorate-doped ice over a range of temperatures (183 - 273 K) and concentrations. Below the eutectic temperature, the perchlorate-doped ice has electrical properties similar to that of choride-doped ice. However, above the eutectic temperature, some of the ice melts forming liquid at triple junctions. At concentrations above 3 mM, the liquid at triple junctions become connected forming brine channels, which greatly increase the dc conductivity and radar attenuation. At concentrations below 3 mM, the liquid at triple junctions are not connected and do not affect the dc conductivity. However, the liquid H2O molecules are able to rotate their permanent dipole at radar frequencies, thus causing an increase in radar attenuation. The MARSIS and SHARAD attenuation rates increase

Natural Attenuation of Perchlorate in Groundwater: Processes, Tools and Monitoring Techniques

DTIC Science & Technology

2008-04-01

attenuation of perchlorate. Tier 3: Microbiological Indicators. For situations where additional lines of evidence are required, Tier 3 offers...USEPA, 1997). Like enhanced bioremediation, MNA requires an in-depth understanding of the microbiology , chemistry, and hydrogeology of the...nitrate, perchlorate (if present), and iron have been depleted in the microbiological treatment zone. Whereas sulfate concentration greater than 20

Perchlorate in Drinking Water Frequent Questions

EPA Pesticide Factsheets

Perchlorate occurs naturally in arid states in the Southwest United States, in nitrate fertilizer deposits in Chile, and in potash ore in the United States and Canada. It has also been found in some public drinking water systems and in food.

COBALT FOLLICULITIS

PubMed Central

Sidell, Chester M.; Erickson, J. Gordon; McCleary, Jack E.

1958-01-01

Clinical observations in 60 cases of folliculitis or pronounced activation of acne in patients taking cobalt led to conclusion that the development or aggravation of the dermal lesions were owing to ingestion of the metal. The dermal manifestations abated when use of cobalt was discontinued. Active acne is considered a contraindication to the use of vitamin-iron-mineral supplements containing cobalt. Short courses of antibiotics in addition to regular acne regimen helped shorten the course of the eruption. ImagesFigure 1. PMID:13489508

[Lead adsorption and arsenite oxidation by cobalt doped birnessite].

PubMed

Yin, Hui; Feng, Xiong-Han; Qiu, Guo-Hong; Tan, Wen-Feng; Liu, Fan

2011-07-01

In order to study the effects of transition metal ions on the physic-chemical properties of manganese dioxides as environmental friendly materials, three-dimensional nano-microsphere cobalt-doped birnessite was synthesized by reduction of potassium permanganate by mixtures of concentrated hydrochloride and cobalt (II) chloride. Powder X-ray diffraction, chemical analysis, N2 physical adsorption, field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectra (XPS) were used to characterize the crystal structure, chemical composition and micro-morphologies of products. In the range of molar ratios from 0.05 to 0.20, birnessite was fabricated exclusively. It was observed that cobalt incorporated into the layers of birnessite and had little effect on the crystal structure and micromorpholgy, but crystallinity decreased after cobalt doping. Both chemical analysis and XPS results showed that manganese average oxidation state decreased after cobalt doping, and the percentage of Mn3+ increased. Co(III) OOH existed mainly in the structure. With the increase of cobalt, hydroxide oxygen percentage in molar increased from 12.79% for undoped birnessite to 13.05%, 17.69% and 17.79% for doped samples respectively. Adsorption capacity for lead and oxidation of arsenite of birnessite were enhanced by cobalt doping. The maximum capacity of Pb2+ adsorption increased in the order HB (2 538 mmol/kg) < CoB5 (2798 mmol/kg) < CoB10 (2932 mmol/kg) < CoB20 (3 146 mmol/kg). Oxidation percentage of arsenite in simulated waste water by undoped birnessite was 76.5%, those of doped ones increased by 2.0%, 12.8% and 18.9% respectively. Partial of Co3+ substitution for Mn4+ results in the increase of negative charge of the layer and the content of hydroxyl group, which could account for the improved adsorption capacity of Pb2+. After substitution of manganese by cobalt, oxidation capacity of arsenite by birnessite increases likely due to the higher standard redox potential of

Perchlorate reduction by hydrogen autotrophic bacteria and microbial community analysis using high-throughput sequencing.

PubMed

Wan, Dongjin; Liu, Yongde; Niu, Zhenhua; Xiao, Shuhu; Li, Daorong

2016-02-01

Hydrogen autotrophic reduction of perchlorate have advantages of high removal efficiency and harmless to drinking water. But so far the reported information about the microbial community structure was comparatively limited, changes in the biodiversity and the dominant bacteria during acclimation process required detailed study. In this study, perchlorate-reducing hydrogen autotrophic bacteria were acclimated by hydrogen aeration from activated sludge. For the first time, high-throughput sequencing was applied to analyze changes in biodiversity and the dominant bacteria during acclimation process. The Michaelis-Menten model described the perchlorate reduction kinetics well. Model parameters q(max) and K(s) were 2.521-3.245 (mg ClO4(-)/gVSS h) and 5.44-8.23 (mg/l), respectively. Microbial perchlorate reduction occurred across at pH range 5.0-11.0; removal was highest at pH 9.0. The enriched mixed bacteria could use perchlorate, nitrate and sulfate as electron accepter, and the sequence of preference was: NO3(-) > ClO4(-) > SO4(2-). Compared to the feed culture, biodiversity decreased greatly during acclimation process, the microbial community structure gradually stabilized after 9 acclimation cycles. The Thauera genus related to Rhodocyclales was the dominated perchlorate reducing bacteria (PRB) in the mixed culture.

Purification and Characterization of (Per)Chlorate Reductase from the Chlorate-Respiring Strain GR-1

PubMed Central

Kengen, Servé W. M.; Rikken, Geoffrey B.; Hagen, Wilfred R.; van Ginkel, Cees G.; Stams, Alfons J. M.

1999-01-01

Strain GR-1 is one of several recently isolated bacterial species that are able to respire by using chlorate or perchlorate as the terminal electron acceptor. The organism performs a complete reduction of chlorate or perchlorate to chloride and oxygen, with the intermediate formation of chlorite. This study describes the purification and characterization of the key enzyme of the reductive pathway, the chlorate and perchlorate reductase. A single enzyme was found to catalyze both the chlorate- and perchlorate-reducing activity. The oxygen-sensitive enzyme was located in the periplasm and had an apparent molecular mass of 420 kDa, with subunits of 95 and 40 kDa in an α3β3 composition. Metal analysis showed the presence of 11 mol of iron, 1 mol of molybdenum, and 1 mol of selenium per mol of heterodimer. In accordance, quantitative electron paramagnetic resonance spectroscopy showed the presence of one [3Fe-4S] cluster and two [4Fe-4S] clusters. Furthermore, two different signals were ascribed to Mo(V). The Kmvalues for perchlorate and chlorate were 27 and <5 μM, respectively. Besides perchlorate and chlorate, nitrate, iodate, and bromate were also reduced at considerable rates. The resemblance of the enzyme to nitrate reductases, formate dehydrogenases, and selenate reductase is discussed. PMID:10542172

The Effects of Perchlorate and its Precursors on Organic Molecules under Simulated Mars Conditions

NASA Astrophysics Data System (ADS)

Carrier, B. L.; Beegle, L. W.; Bhartia, R.; Abbey, W. J.

2016-12-01

Perchlorate (ClO4-) was first detected on Mars by the Phoenix Lander in 2008 [1] and has subsequently been detected by Curiosity in Gale Crater [2], in Mars meteorite EETA79001 [3], and has been proposed as a possible explanation for results obtained by Viking [4]. Perchlorate has also been shown to be formed under current Mars conditions via the oxidation of mineral chlorides, further supporting the theory that perchlorate is present globally on Mars [5]. The discovery of perchlorate on Mars has raised important questions about its effects on the survival and detection of organic molecules. Although it has been shown that pyrolysis in the presence of perchlorate results in the alteration or destruction of organic molecules [2, 4], few studies have been conducted on the potential effects of perchlorate and its precursors on organic molecules prior to analysis. Perchlorate is typically inert under Mars temperatures and pressures, but it has been shown to decompose to form reactive oxychlorine species such as chlorite (ClO2-), hypochlorite (ClO-) and chlorine dioxide (ClO2) when exposed to Mars conditions including ionizing radiation [6]. The oxidation of chloride to perchlorate also results in the formation of reactive oxychlorine species such as chlorate (ClO3-) [5]. Here we investigate the effects of perchlorate and its oxychlorine precursors on organic molecules. Experiments are performed in a Mars Simulation Chamber (MSC) capable of reproducing the temperature, pressure, atmospheric composition and UV flux found on Mars. Soil simulants are prepared consisting of Mojave Mars Simulant (MMS) [7] and each organic, as well as varying concentrations of perchlorate and/or chloride salts, and exposed in the MSC. Subsequent to exposure in the MSC samples are leached and the leachate analyzed by HPLC and LC-MS to determine the degree of degradation of the original organic and the identity of any potential decomposition products formed by oxidation or chlorination

Effect of fireworks display on perchlorate in air aerosols during the Spring Festival

NASA Astrophysics Data System (ADS)

Shi, Yali; Zhang, Ning; Gao, Jianmin; Li, Xin; Cai, Yaqi

2011-02-01

Perchlorate is regarded as a new emerging persistent inorganic environmental contaminant. It can result in important neurodevelopmental deficits and goiter in infants and children because of its inhibition of iodine uptake into the thyroid tissue. Furthermore, its presence in the human body can cause improper regulation of metabolism for adults. It is often used as ingredient in the production of fireworks. So fireworks display may influence the perchlorate levels in atmospheric particulate matter (PM). In this paper perchlorate was determined in air aerosol samples (Inhalable particulate matter (PM10) and larger particulate matter (PM10-100)) collected from two locations (Lanzhou City and Yuzhong County) in Gansu province over a month period (February 1rst to March 4th) during the Spring Festival (February 18th) in 2007 in order to study the effect of fireworks display on perchlorate in air aerosol. The results showed that different concentrations of perchlorate were detected in almost all samples, ranging from perchlorate were 91% (100%) and 50% (59%) for PM10-100 (PM10) in Lanzhou City and Yuzhong County, respectively. The highest concentrations were all found in the samples from two sites on New Year's Eve, which was 39.16 ng m -3 (PM10-100) and 9.89 ng m -3 (PM10) for Lanzhou city, 3.43 ng m -3 (PM10-100) and 4.97 ng m -3 (PM10) for Yuzhong County, 6.8-26.2 times as the mean concentrations during the period of no or limited fireworks display. This indicated that the fireworks display during the Spring Festival can result in the levels of perchlorate increase.

High-nitrogen-based pyrotechnics: development of perchlorate-free green-light illuminants for military and civilian applications.

PubMed

Sabatini, Jesse J; Raab, James M; Hann, Ronald K; Damavarapu, Reddy; Klapötke, Thomas M

2012-06-01

The development of perchlorate-free hand-held signal illuminants for the US Army's M195 green star parachute is described. Compared with the perchlorate-containing control, the optimized perchlorate-free illuminants were less sensitive toward various ignition stimuli while offering comparable burn times and visible-light outputs. The results were also important from the perspective of civilian fireworks because the development of perchlorate-free illuminants remains an important objective of the commercial fireworks industry. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Perchlorate Formation on Mars Through Surface Radiolysis-Initiated Atmospheric Chemistry: A Potential Mechanism

NASA Technical Reports Server (NTRS)

Wilson, Eric H.; Atreya, Sushil K.; Kaiser, Ralf I.; Mahaffy, Paul R.

2016-01-01

Recent observations of the Martian surface by the Phoenix lander and the Sample Analysis at Mars indicate the presence of perchlorate (ClO4). The abundance and isotopic composition of these perchlorates suggest that the mechanisms responsible for their formation in the Martian environment may be unique in our solar system. With this in mind, we propose a potential mechanism for the production of Martian perchlorate: the radiolysis of the Martian surface by galactic cosmic rays, followed by the sublimation of chlorine oxides into the atmosphere and their subsequent synthesis to form perchloric acid (HClO4) in the atmosphere, and the surface deposition and subsequent mineralization of HClO4 in the regolith to form surface perchlorates. To evaluate the viability of this mechanism, we employ a one-dimensional chemical model, examining chlorine chemistry in the context of Martian atmospheric chemistry. Considering the chlorine oxide, OClO, we find that an OClO flux as low as 3.2 x 10(exp 7) molecules/sq cm/s sublimated into the atmosphere from the surface could produce sufficient HClO4 to explain the perchlorate concentration on Mars, assuming an accumulation depth of 30 cm and integrated over the Amazonian period. Radiolysis provides an efficient pathway for the oxidation of chlorine, bypassing the efficient Cl/HCl recycling mechanism that characterizes HClO4 formation mechanisms proposed for the Earth but not Mars.

The Effects of Ammonium Perchlorate on Reproduction and Development of Amphibians

DTIC Science & Technology

2008-01-01

Abstract: Ammonium perchlorate is a pervasive pollutant primarily from rocket fuel and fertilizers . It is know , among other things , to affect...females, their ovulated eggs collected, and in vitro fertilization conducted. Healthy ovulated eggs were selected and placed in Petri dishes...used and fertilization accomplished in vitro in the presence of perchlorate concentrations. *These tasks were not completed. Studies with Sodium

Development of a Reference Dose for Perchlorate: Current Issues and Status

NASA Technical Reports Server (NTRS)

Pleus, R. C.; Goodman, G.; Mattie, D. R.

2000-01-01

The perchlorate anion (ClO4) is typically manufactured as the ammonium salt. The most common use of ammonium perchlorate is in the aerospace program as a component of solid rocket fuel. The perchlorate anion is exceedingly stable under environmental conditions and has been found in ground and surface waters in CA, NV, UT, AZ, TX, AK, NY, MD, WV and FL. The National Center for Environmental Assessment (NCEA) of the U.S. Environmental Protection Agency (US EPA) is in the process of developing an oral reference dose (RfD) for perchlorate. An oral RfD is a body-weight-adjusted dose that can be consumed daily over an entire lifetime with the expectation of no adverse health effects. Once developed, the new RfD will be used by US EPA as the basis of a safe-drinking-water level (SDWL) guideline. US EPA and regional regulatory agencies will then jointly or separately propose clean-up action levels for ground and surface waters at contaminated sites. The toxicological database on CIO4- as of March 1997 was determined by an expert peer-review panel to be inadequate for the purpose of deriving an oral RfD. For example, little or no experimental data existed on the subchronic, reproductive, or developmental toxicity of perchlorate. To fill gaps in the toxicological database, eight animal studies were designed by a government-industry consortium that included US EPA and AFRL. These studies were performed in 1997-1998. It has been known for many years that in the thyroid, high doses of perchlorate block the function of iodide by competing for iodide binding sites. Perchlorate was used in the 1950s-60s as a treatment for Graves' disease (a hyperthyroid condition). Because of what was already known about the pharmacological mode of action of perchlorate, specific concerns addressed in the design of the recent animal studies included the potential for developmental toxicity, notably neurological development. Upon review of complete study reports from four of the studies and

Effect of Hydration State of Martian Perchlorate Salts on their Decomposition Temperatures during Thermal Extraction

NASA Astrophysics Data System (ADS)

Royle, S. H.; Montgomery, W.; Kounaves, S. P.; Sephton, M. A.

2017-12-01

A number of missions to Mars have analyzed the composition of surface samples using thermal extraction techniques. The temperatures of decomposition have been used as diagnostic information for the materials present. One material of great current interest is perchlorate, a relatively recently discovered component of Mars surface geochemistry that leads to deleterious effects on organic matter during thermal extraction. Knowledge of the thermal decomposition behavior of perchlorate salts is essential for mineral identification and possible avoidance of confounding interactions with organic matter. We have performed a series of stepped pyrolysis experiments on samples of magnesium perchlorate hydrate which were dehydrated to various extents - as confirmed by XRD and FTIR analysis. Our data reveal that the hydration state of magnesium perchlorate has a significant effect on decomposition temperature, with differing temperature releases of oxygen corresponding to different perchlorate hydration states. We find that the peak temperature of oxygen release increases from 500 to 600°C as the proportion of the tetrahydrate form in the sample increases and the hexahydrate form decreases. It was known previously that cation chemistry can affect the temperature of oxygen release and now our work shows that the hydration state of these salts can lead to similar variations. Consequently, incorrect identification of perchlorate species may occur if hydration state is not taken into account and a mixture of metastable hydration states (of one type of perchlorate) may be mistaken for a mixture of perchlorate salts. Our findings are important for Mars as the hydration state of salts in the regolith may change throughout the Martian year due to large variations in humidity and temperature.

Rapid analysis of perchlorate in drinking water at parts per billion levels using microchip electrophoresis.

PubMed

Gertsch, Jana C; Noblitt, Scott D; Cropek, Donald M; Henry, Charles S

2010-05-01

A microchip capillary electrophoresis (MCE) system has been developed for the determination of perchlorate in drinking water. The United States Environmental Protection Agency (USEPA) recently proposed a health advisory limit for perchlorate in drinking water of 15 parts per billion (ppb), a level requiring large, sophisticated instrumentation, such as ion chromatography coupled with mass spectrometry (IC-MS), for detection. An inexpensive, portable system is desired for routine online monitoring applications of perchlorate in drinking water. Here, we present an MCE method using contact conductivity detection for perchlorate determination. The method has several advantages, including reduced analysis times relative to IC, inherent portability, high selectivity, and minimal sample pretreatment. Resolution of perchlorate from more abundant ions was achieved using zwitterionic, sulfobetaine surfactants, N-hexadecyl-N,N-dimethyl-3-ammonio-1-propane sulfonate (HDAPS) and N-tetradecyl-N,N-dimethyl-3-ammonio-1-propane sulfonate (TDAPS). The system performance and the optimization of the separation chemistry, including the use of these surfactants to resolve perchlorate from other anions, are discussed in this work. The system is capable of detection limits of 3.4 +/- 1.8 ppb (n = 6) in standards and 5.6 +/- 1.7 ppb (n = 6) in drinking water.

Perchlorate in Turfgrass Systems, Suffolk County, Long Island, NY

NASA Astrophysics Data System (ADS)

Munster, J. E.; Hanson, G. N.; Jackson, W. A.

2007-12-01

Perchlorate concentrations in precipitation, grass clippings, and soil water were analyzed at nine turfgrass sites in Suffolk County, NY. The samples were collected monthly between June, 2006 and January, 2007. The soil water was collected from suction lysimeters at 100 cm depth. Four of these sites were treated with chemical fertilizer, three with organic fertilizer and two were not fertilized. Concentrations of ClO4 in grass clippings and soil water, at the sites treated with chemical fertilizer or not treated with fertilizer, are found to increase when spikes of ClO4 concentrations in precipitation are observed. We believe that the spikes in perchlorate in precipitation collected shortly after the Fourth of July are due to firework displays. The concentration of ClO4 in soil water are 1 to 3 times higher than the maximum perchlorate concentrations in precipitation, with maximum soil water concentrations ranging from 0.5 to 3.0 ppb. At the sites treated with organic fertilizer, grass clippings and soil water ClO4 concentrations increase after the fertilizer application in May. The organic fertilizer that was applied has nine mg ClO4 per kg (9,000 ppb). Soil water concentrations at the sites treated with organic fertilizer increase 100 to 300 times the maximum ClO4 concentration observed in precipitation, with maximum soil water concentrations ranging from 120 to 625 ppb. The increase in ClO4 concentrations in the soil water cannot be explained by evaporation alone since the Cl to ClO4 ratios decrease in the soil water relative to precipitation. This decrease in the Cl to ClO4 ratio suggests another source of perchlorate besides precipitation. We postulate that this additional source is associated with the decomposition of mulched grass left after mowing. Grass takes only a few weeks to decompose after mulching, thus providing a continuous source of perchlorate throughout the mowing season. The Cl to ClO4 ratio of the grass is unknown.

Perchlorate and Superfund Response to Uncertainty and the Geochemical Cycle

NASA Astrophysics Data System (ADS)

Mayer, K. P.

2007-12-01

Perchlorate, a chemical that had been known both in nature and through synthesis since the nineteenth century, only emerged into the limelight as an environmental contaminant in 1997. US EPA's Superfund Program became involved in perchlorate issues in the late 1980s and early 1990s due to the chemical's presence mixed with other contaminants at cleanup sites. Relying largely on pharmaceutical studies primarily from the 1950s and 1960s, EPA scientists in 1992 made a provisional estimate of toxicity and estimated that about 4 micrograms per liter (parts per billion or ppb) in drinking water would be protective. "Uncertainty factors" were incorporated to address for several identified information gaps. Results of new animal and human studies funded by the Defense Department and industry in the late 1990s shifted the concern from affects on adults with unhealthy thyroids to the potential developmental health risks to infants and children. EPA's January, 2002, draft toxicity assessment was referred to a committee of the National Research Council. In January, 2005, this committee recommended a "reference dose" based primarily on human clinical data. Many decisions remain on interpretation of the scientific recommendations for regulatory applications. After California's 1997 development of an analytical method to detect perchlorate in water to 4 ppb, EPA and state officials quickly discovered this chemical at 10 Superfund sites in the Pacific Southwest Region and at more than 30 other locations in California, Arizona and Nevada. Even before current research on the potential for natural sources of this anion, reported detections of perchlorate were investigated with reasonable care and appropriate skepticism. A brief overview of the search for likely sources of perchlorate detected in California water supplies is presented from a regional Superfund perspective. Some are clearly anthropogenic and others may be unrelated to industrial or disposal practices. Currently, there

Efflorescence of Magnesium Perchlorate by Contact with Mineral Dust Particles

NASA Astrophysics Data System (ADS)

Ushijima, S.; Tolbert, M. A.; Gough, R. V.

2017-12-01

Liquid water was not uncommon on early Mars and it shaped geologic features on the surface that are still seen today. Due to the extremely cold and dry conditions of Mars currently, only water ice and water vapor have been observed and or detected. However, it has been suggested that liquid may form seasonally based on the observations of recurring slope lineae (RSL). The liquid may be a brine composed of hygroscopic salts such as perchlorates whose hydrated form has recently been detected in an RSL by the Mars Reconnaissance Orbiter. Through a process called deliquescence, the salts can absorb water from the surrounding environment and become a brine above a specific relative humidity (RH) known as the deliquescence relative humidity (DRH). The reverse process, recrystallization or efflorescence, often occurs at a much lower RH called the efflorescence relative humidity (ERH). The hysteresis effect caused by the distinctly different RH values allows for liquid brines to be metastable even under dry conditions. However, there is evidence that ERH can be raised when a mineral particle encounters the surface of the brine or it is immersed inside, effectively diminishing the metastability potential of liquid brines. If the brines are responsible for RSL formation, the brine will inevitably mix with the Martian soil. Thus, it is important to understand the effects that mineral particles can have on efflorescence. Here we use optical trapping to examine efflorescence of magnesium perchlorate in the presence of montmorillonite and halite. Studies on the efflorescence and deliquescence of magnesium perchlorate has shown that its brine could be stable in the subsurface of Mars during certain periods of time. Both montmorillonite and halite have been suggested to be a part of or similar to components of the Martian soil. Results at ambient conditions have shown that efflorescence of magnesium perchlorate is unaffected by the presence of either minerals. Whether the droplet

Perchlorates on Mars enhance the bacteriocidal effects of UV light.

PubMed

Wadsworth, Jennifer; Cockell, Charles S

2017-07-06

Perchlorates have been identified on the surface of Mars. This has prompted speculation of what their influence would be on habitability. We show that when irradiated with a simulated Martian UV flux, perchlorates become bacteriocidal. At concentrations associated with Martian surface regolith, vegetative cells of Bacillus subtilis in Martian analogue environments lost viability within minutes. Two other components of the Martian surface, iron oxides and hydrogen peroxide, act in synergy with irradiated perchlorates to cause a 10.8-fold increase in cell death when compared to cells exposed to UV radiation after 60 seconds of exposure. These data show that the combined effects of at least three components of the Martian surface, activated by surface photochemistry, render the present-day surface more uninhabitable than previously thought, and demonstrate the low probability of survival of biological contaminants released from robotic and human exploration missions.

Perchlorate bioreduction linked to methane oxidation in a membrane biofilm reactor: Performance and microbial community structure.

PubMed

Xie, Ting; Yang, Qi; Winkler, Mari K H; Wang, Dongbo; Zhong, Yu; An, Hongxue; Chen, Fei; Yao, Fubin; Wang, Xiaolin; Wu, Jiawei; Li, Xiaoming

2018-06-05

Perchlorate bioreduction coupled to methane oxidation was successfully achieved without the addition of nitrate or nitrite in a membrane biofilm reactor (MBfR) inoculated with a mixture of freshwater sediments and anaerobic digester sludge as well as return activated sludge. The reactor was operated at different methane pressures (60, 40 and 20 Kpa) and influent perchlorate concentrations (1, 5 and 10 mg/L) to evaluate the biochemical process of perchlorate bioreduction coupled to methane oxidation. Perchlorate was completely reduced with a higher removal flux of 92.75 mg/m 2 ·d using methane as the sole carbon source and electron donor, other than hydrogen or other limiting organics. Quantitative real-time PCR showed that bacteria prevailed over archaea and the abundances of mcrA, pMMO, pcrA, and nirS genes were correlated with the influent perchlorate flux. High-throughput sequencing of 16S rRNA genes demonstrated that the functional community consisted of methanotrophs, methylotrophs, perchlorate-reducing bacteria, as well as various denitrifiers. Copyright © 2018 Elsevier B.V. All rights reserved.

Rapid measurement of perchlorate in polar ice cores down to sub-ng L(-1) levels without pre-concentration.

PubMed

Peterson, Kari; Cole-Dai, Jihong; Brandis, Derek; Cox, Thomas; Splett, Scott

2015-10-01

An ion chromatography-electrospray ionization-tandem mass spectrometry (IC-ESI-MS/MS) method has been developed for rapid and accurate measurement of perchlorate in polar snow and ice core samples in which perchlorate concentrations are expected to be as low as 0.1 ng L(-1). Separation of perchlorate from major inorganic species in snow is achieved with an ion chromatography system interfaced to an AB SCIEX triple quadrupole mass spectrometer operating in multiple reaction monitoring mode. Under optimized conditions, the limit of detection and lower limit of quantification without pre-concentration have been determined to be 0.1 and 0.3 ng L(-1), respectively, with a linear dynamic range of 0.3-10.0 ng L(-1) in routine measurement. These represent improvements over previously reported methods using similar analytical techniques. The improved method allows fast, accurate, and reproducible perchlorate quantification down to the sub-ng L(-1) level and will facilitate perchlorate measurement in the study of natural perchlorate production with polar ice cores in which perchlorate concentrations are anticipated to vary in the low and sub-ng L(-1) range. Initial measurements of perchlorate in ice core samples from central Greenland show that typical perchlorate concentrations in snow dated prior to the Industrial Revolution are about 0.8 ng L(-1), while perchlorate concentrations are significantly higher in recent (post-1980) snow, suggesting that anthropogenic sources are a significant contributor to perchlorate in the current environment.

The Perchlorate Reduction Genomic Island: Mechanisms and Pathways of Evolution by Horizontal Gene Transfer.

PubMed

Melnyk, Ryan A; Coates, John D

2015-10-26

Perchlorate is a widely distributed anion that is toxic to humans, but serves as a valuable electron acceptor for several lineages of bacteria. The ability to utilize perchlorate is conferred by a horizontally transferred piece of DNA called the perchlorate reduction genomic island (PRI). We compared genomes of perchlorate reducers using phylogenomics, SNP mapping, and differences in genomic architecture to interrogate the evolutionary history of perchlorate respiration. Here we report on the PRI of 13 genomes of perchlorate-reducing bacteria from four different classes of Phylum Proteobacteria (the Alpha-, Beta-, Gamma- and Epsilonproteobacteria). Among the different phylogenetic classes, the island varies considerably in genetic content as well as in its putative mechanism and location of integration. However, the islands of the densely sampled genera Azospira and Magnetospirillum have striking nucleotide identity despite divergent genomes, implying horizontal transfer and positive selection within narrow phylogenetic taxa. We also assess the phylogenetic origin of accessory genes in the various incarnations of the island, which can be traced to chromosomal paralogs from phylogenetically similar organisms. These observations suggest a complex phylogenetic history where the island is rarely transferred at the class level but undergoes frequent and continuous transfer within narrow phylogenetic groups. This restricted transfer is seen directly by the independent integration of near-identical islands within a genus and indirectly due to the acquisition of lineage-specific accessory genes. The genomic reversibility of perchlorate reduction may present a unique equilibrium for a metabolism that confers a competitive advantage only in the presence of an electron acceptor, which although widely distributed, is generally present at low concentrations in nature.

Containerized Wetland Bioreactor Evaluated for Perchlorate and Nitrate Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dibley, V R; Krauter, P W

2004-12-02

The U.S. Department of Energy (DOE) and Lawrence Livermore Laboratory (LLNL) designed and constructed an innovative containerized wetlands (bioreactor) system that began operation in November 2000 to biologically degrade perchlorate and nitrate under relatively low-flow conditions at a remote location at Site 300 known as Building 854. Since initial start-up, the system has processed over 3,463,000 liters of ground water and treated over 38 grams of perchlorate and 148 kilograms of nitrate. Site 300 is operated by the University of California as a high-explosives and materials testing facility supporting nuclear weapons research. The 11-square mile site located in northern Californiamore » was added to the NPL in 1990 primarily due to the presence of elevated concentrations of volatile organic compounds (VOCs) in ground water. At the urging of the regulatory agencies, perchlorate was looked for and detected in the ground water in 1999. VOCs, nitrate and perchlorate were released into the soil and ground water in the Building 854 area as the result of accidental leaks during stability testing of weapons or from waste discharge practices that are no longer permitted at Site 300. Design of the wetland bioreactors was based on earlier studies showing that indigenous chlorate-respiring bacteria could effectively degrade perchlorate into nontoxic concentrations of chlorate, chlorite, oxygen, and chloride. Studies also showed that the addition of organic carbon would enhance microbial denitrification. Early onsite testing showed acetic acid to be a more effective carbon source than dried leaf matter, dried algae, or milk replacement starter; a nutrient and carbon source used in a Department of Defense phytoremediation demonstration. No inocula were added to the system. Groundwater was allowed to circulate through the bioreactor for three weeks to acclimate the wetland plants and to build a biofilm from indigenous flora. Using solar energy, ground water is pumped into

Dissimilatory perchlorate reduction linked to aerobic methane oxidation via chlorite dismutase

NASA Astrophysics Data System (ADS)

Oremland, R. S.; Baesman, S. M.; Miller, L. G.

2013-12-01

The presence of methane (CH4) in the atmosphere of Mars is controversial yet the evidence has aroused scientific interest, as CH4 could be a harbinger of extant or extinct microbial life. There are various oxidized compounds present on the surface of Mars that could serve as electron acceptors for the anaerobic oxidation of CH4, including perchlorate (ClO4-). We examined the role of perchlorate, chlorate (ClO3-) and chlorite (ClO2-) as oxidants linked to CH4 oxidation. Dissimilatory perchlorate reduction begins with reduction of ClO4- to ClO2- and ends with dismutation of chlorite to yield chloride (Cl-) and molecular oxygen (O2). We explored the potential for aerobic CH4 oxidizing bacteria to couple with oxygen derived from chlorite dismutation during dissimilatory perchlorate reduction. Methane (0.2 kPa) was completely removed within several days from the N2-flushed headspace above cell suspensions of methanotrophs (Methylobacter albus strain BG8) and perchlorate reducing bacteria (Dechloromonas agitata strain CKB) in the presence of 5 mM ClO2-. Similar rates of CH4 consumption were observed for these mixed cultures whether they were co-mingled or segregated under a common headspace, indicating that direct contact of cells was not required for methane consumption to occur. We also observed complete removal of 0.2 kPa CH4 in bottles containing dried soil (enriched in methanotrophs by CH4 additions over several weeks) and D. agitata CKB and in the presence of 10 mM ClO2-. This soil (seasonally exposed sediment) collected from the shoreline of a freshwater lake (Searsville Lake, CA) demonstrated endogenous CH4 uptake as well as perchlorate, chlorate and chlorite reduction/dismutation. However, these experiments required physical separation of soil from the aqueous bacterial culture to allow for the partitioning of O2 liberated from chlorite dismutation into the shared headspace. Although dissimilatory reduction of ClO4- and ClO3- could be inferred from the

DEVELOPMENT OF A BETTER METHOD TO IDENTIFY AND MEASURE PERCHLORATE IN DRINKING WATER

EPA Science Inventory

Perchlorate (ClO4 -) is an oxidant used primarily in solid propellant for rockets, missiles, pyrotechnics, as a component in air bag inflators, and in highway safety flares. Perchlorate tainted water has been found throughout the southwestern United States where its source has o...

Cobalt-Catalyzed C(sp(2))-H Borylation: Mechanistic Insights Inspire Catalyst Design.

PubMed

Obligacion, Jennifer V; Semproni, Scott P; Pappas, Iraklis; Chirik, Paul J

2016-08-24

A comprehensive study into the mechanism of bis(phosphino)pyridine (PNP) cobalt-catalyzed C-H borylation of 2,6-lutidine using B2Pin2 (Pin = pinacolate) has been conducted. The experimentally observed rate law, deuterium kinetic isotope effects, and identification of the catalyst resting state support turnover limiting C-H activation from a fully characterized cobalt(I) boryl intermediate. Monitoring the catalytic reaction as a function of time revealed that borylation of the 4-position of the pincer in the cobalt catalyst was faster than arene borylation. Cyclic voltammetry established the electron withdrawing influence of 4-BPin, which slows the rate of C-H oxidative addition and hence overall catalytic turnover. This mechanistic insight inspired the next generation of 4-substituted PNP cobalt catalysts with electron donating and sterically blocking methyl and pyrrolidinyl substituents that exhibited increased activity for the C-H borylation of unactivated arenes. The rationally designed catalysts promote effective turnover with stoichiometric quantities of arene substrate and B2Pin2. Kinetic studies on the improved catalyst, 4-(H)2BPin, established a change in turnover limiting step from C-H oxidative addition to C-B reductive elimination. The iridium congener of the optimized cobalt catalyst, 6-(H)2BPin, was prepared and crystallographically characterized and proved inactive for C-H borylation, a result of the high kinetic barrier for reductive elimination from octahedral Ir(III) complexes.

Biodegradation of rocket propellent waste, ammonium perchlorate

NASA Technical Reports Server (NTRS)

Naqui, S. M. Z.

1975-01-01

The impact of the biodegradation rate of ammonium perchlorate on the environment was studied in terms of growth, metabolic rate, and total biomass of selected animal and plant species. Brief methodology and detailed results are presented.

Effect of Hydration State of Martian Perchlorate Salts on Their Decomposition Temperatures During Thermal Extraction

NASA Astrophysics Data System (ADS)

Royle, Samuel H.; Montgomery, Wren; Kounaves, Samuel P.; Sephton, Mark A.

2017-12-01

Three Mars missions have analyzed the composition of surface samples using thermal extraction techniques. The temperatures of decomposition have been used as diagnostic information for the materials present. One compound of great current interest is perchlorate, a relatively recently discovered component of Mars' surface geochemistry that leads to deleterious effects on organic matter during thermal extraction. Knowledge of the thermal decomposition behavior of perchlorate salts is essential for mineral identification and possible avoidance of confounding interactions with organic matter. We have performed a series of experiments which reveal that the hydration state of magnesium perchlorate has a significant effect on decomposition temperature, with differing temperature releases of oxygen corresponding to different perchlorate hydration states (peak of O2 release shifts from 500 to 600°C as the proportion of the tetrahydrate form in the sample increases). Changes in crystallinity/crystal size may also have a secondary effect on the temperature of decomposition, and although these surface effects appear to be minor for our samples, further investigation may be warranted. A less than full appreciation of the hydration state of perchlorate salts during thermal extraction analyses could lead to misidentification of the number and the nature of perchlorate phases present.

ASSOCIATION OF URINARY PERCHLORATE WITH INDIRECT MEASURES OFTHYROID DYSFUNCTION BASED ON NHANES 2001-2002

EPA Science Inventory

Background/Aims: Perchlorate is a widespread environmental pollutant. Previous population studies based on the National Health and Nutrition Examination Survey (NHANES) 2001-2002, showed that urinary perchlorate concentrations were associated with increased levels of thyroid stim...

Mechanical properties of nanocrystalline cobalt

NASA Astrophysics Data System (ADS)

Karimpoor, Amir A.; Erb, Uwe

2006-05-01

Due to their excellent wear and corrosion properties, nanocrystalline cobalt and several cobalt alloys made by electrodeposition are currently being developed as environmentally benign replacement coatings for hard chromium electrodeposits. The focus of this study is on the mechanical properties of nanocrystalline cobalt, which are currently not well understood. A comparison is presented for hardness, tensile properties, Charpy impact properties and fracture surface analysis of both nanocrystalline (grain size: 12 nm) and conventional polycrystalline (grain size: 4.8 m) cobalt. It is shown that the hardness and tensile strength of nanocrystalline cobalt is 2-3 times higher than for polycrystalline cobalt. However, in contrast to other nanocrystalline materials tested previously, nanocrystalline cobalt retains considerable ductility with elongation to fracture values up to 7%.

Determination of perchlorate in drinking water by ion chromatography using macrocycle-based concentration and separation methods.

PubMed

Lamb, John D; Simpson, David; Jensen, Bryce D; Gardner, Joseph S; Peterson, Quinn P

2006-06-16

Macrocycle-based ion chromatography provides a convenient, reliable method for the determination of perchlorate ion, which is currently of great interest to the environmental community. This study shows that effective perchlorate determinations can be made using standard conductimetric detection by combining an 18-crown-6-based mobile phase with an underivatized reversed-phase mobile phase ion chromatography (MPIC) column. One unique feature of this method is the flexibility in column capacity that is achieved through simple variations in eluent concentrations of 18-crown-6 and KOH, facilitating the separation of target analyte anions such as perchlorate. Using a standard anion exchange column as concentrator makes possible the determination of perchlorate as low as 0.2 ug/L in low ionic strength matrices. Determination of perchlorate at the sub-ug/L level in pure water and in spiked local city hard water samples with high background ion concentrations can be achieved this way. However, like other IC techniques, this method is challenged to achieve analyses at the ug/L level in the demanding high ionic strength matrix described by the United States Environmental Protection Agency (EPA) (1,000 mg/L chloride, sulfate and carbonate). We approached this challenge by use of the Cryptand C1 concentrator column, provided by Dionex Corporation, to effectively preconcentrate perchlorate while reducing background ion concentrations in the high ionic strength matrix. The retention characteristics of the concentrator column were studied in order to maximize its effectiveness for perchlorate determinations. The method makes possible the determination of perchlorate at the 5 ug/L level in the highest ionic strength matrix described by the EPA.

Perchlorate radiolysis on Mars and the origin of martian soil reactivity.

PubMed

Quinn, Richard C; Martucci, Hana F H; Miller, Stephanie R; Bryson, Charles E; Grunthaner, Frank J; Grunthaner, Paula J

2013-06-01

Results from the Viking biology experiments indicate the presence of reactive oxidants in martian soils that have previously been attributed to peroxide and superoxide. Instruments on the Mars Phoenix Lander and the Mars Science Laboratory detected perchlorate in martian soil, which is nonreactive under the conditions of the Viking biology experiments. We show that calcium perchlorate exposed to gamma rays decomposes in a CO2 atmosphere to form hypochlorite (ClO(-)), trapped oxygen (O2), and chlorine dioxide (ClO2). Our results show that the release of trapped O2 (g) from radiation-damaged perchlorate salts and the reaction of ClO(-) with amino acids that were added to the martian soils can explain the results of the Viking biology experiments. We conclude that neither hydrogen peroxide nor superoxide is required to explain the results of the Viking biology experiments.

ELECTROCHEMICAL TREATMENT AND RECYCLING OF SPENT PERCHLORATE-CONTAMINATED ION-EXCHANGE REGENERATION BRINE - PHASE I

EPA Science Inventory

Eltron Research & Development, Inc. (Eltron) proposes to develop an ion-selective, polymer membrane electrode capable of detecting perchlorate in water at low parts per billion (ppb) concentrations. With the discovery of perchlorate contamination in an increasing number of...

Potential Influence of Perchlorate on Heavy Metals and Organic Carbon in Serpentine Soil; Implications for Martian Regolith

NASA Astrophysics Data System (ADS)

Oze, C.; Kumarathilaka, P. R.; Indraratne, S.; Vithanage, M. S.

2015-12-01

Prasanna Kumarathilaka Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, Sri LankaPerchlorate (ClO4-) concentrations as high as 1 Wt.% have been reported in Martian regolith. Perchlorate is a strong oxidizer capable of accelerating heavy and/or trace metal release into regolith/soil and reacting with organic matter/compounds (if present). Here, we assess interactions between perchlorate and an analogous Martian regolith (i.e., serpentine soil) to simulate and understand the fate of Mn, Ni and Co and organic carbon. Pre-characterized serpentine soil collected from Sri Lanka was used for this study. Incubation experiments were performed with three perchlorate concentrations (1, 0.75 and 0.5 w/w) and sequential and single extractions assessed solid phase metal fractionation in serpentine sediments after 3 weeks and 1 year, respectively. Additionally, total organic carbon (TOC) of the residues were analyzed. These experiments demonstrate a high release of Mn compared to Ni and Co. Metal concentrations in exchangeable and bioavailable fractions increased with increasing perchlorate concentrations. Exchangeable Ni, Mn and Co increased 5.9, 69.6 and 44.6% and bioavailable Ni, Mn and Co increased 5.5, 92.3 and 72.8%, respectively, after 1 year compared to 3 weeks. Additionally, TOC decreased with increasing perchlorate concentration. For example, TOC decreased by 14.3% after 1 year compared to a 3 week incubation period. Overall, this study confirms the accelerated release of metals and the removal of organic carbon with increasing perchlorate concentrations. Furthermore, this study illustrates how perchlorate may present additional challenges to current Martian life studies and the future human habitation of Mars.Prasanna Kumarathilaka Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, Sri LankaPerchlorate (ClO4-) concentrations as high as 1 Wt.% have

COMMENT ON "PERCHLORATE IDENTIFICATION IN FERTILIZERS" AND THE SUBSEQUENT ADDITION/CORRECTION [LETTER TO EDITOR

EPA Science Inventory

Perchlorate contamination has been reported in several fertilizer materials and not just in mined Chile saltpeter, where it is a welo-known natural impurity. To survey fertilizers for perchlorate, two analytical techniques have been applied to 45 products that span agricultural, ...

PERCHLORATE UPTAKE BY SALT CEDAR (TAMARIX RAMOSISSIMA) IN THE LAS VEGAS WASH RIPARIAN ECOSYSTEM

EPA Science Inventory

Perchlorate ion (CIO4-) has been identified in samples of dormant salt cedar (Tamarix ramosissima) growing in the Las vegas Wash. Perchlorate is an oxidenat, but its reduction is kineticaly hindered. CXoncern over thyrpoid effects caused the Environmental Protection Agency (EPA...

Structural elucidation, EPR and magnetic property of a Co(III) complex salt incorporating 4,4‧-bipyridine and 5-sulfoisophthalate

NASA Astrophysics Data System (ADS)

Das, Kuheli; Datta, Amitabha; Pevec, Andrej; Mane, Sandeep B.; Rameez, Mohammad; Garribba, Eugenio; Akitsu, Takashiro; Tanka, Shinnosuke

2018-01-01

The cobalt(III) derivative [Co3(sip)4(bipy)2(H2O)10][Co(bipy)2(H2O)4]3(sip)2·20H2O (1) has been hydro(solvo) thermally synthesized by combining sodium 5-sulfoisophthalate (sipH2Na) as organic linker, divalent cobalt nitrate hexahydrate as metal salt and the flexible N-donor ancillary ligand bipy (4,4‧-bipyridine). Compound 1 is an ionic solid consisting of both cobalt containing cations and anions and also in addition 5-sulfoisophthalate anions. Cobalt containing cations in the crystal structure are mononuclear complex while cobalt containing anion is a discrete trinuclear species. The π-π interaction present in 1 results in chain supramolecular structure. The encapsulation of the cobalt compound displays a moderate luminescent property. On temperature dependent magnetic study, it is revealed that the corresponding effective magnetic moment is 5.27 B.M. at 300 K, which suggests isolated Co(III) species with S = 2 (theoretical value is 4.90 B M.) and thus 1 shows a rare paramagnetic behavior.

Perchlorate-Coupled Carbon Monoxide (CO) Oxidation: Evidence for a Plausible Microbe-Mediated Reaction in Martian Brines.

PubMed

Myers, Marisa R; King, Gary M

2017-01-01

The presence of hydrated salts on Mars indicates that some regions of its surface might be habitable if suitable metabolizable substrates are available. However, several lines of evidence have shown that Mars' regolith contains only trace levels of the organic matter needed to support heterotrophic microbes. Due to the scarcity of organic carbon, carbon monoxide (CO) at a concentration of about 700 parts per million (about 0.4 Pa) might be the single most abundant readily available substrate that could support near-surface bacterial activity. Although a variety of electron acceptors can be coupled to CO oxidation, perchlorate is likely the most abundant potential oxidant in Mars' brines. Whether perchlorate, a potent chaotrope, can support microbial CO oxidation has not been previously documented. We report here the first evidence for perchlorate-coupled CO oxidation based on assays with two distinct euryarchaeal extreme halophiles. CO oxidation occurred readily in 3.8 M NaCl brines with perchlorate concentrations from 0.01 to 1 M. Both isolates were able to couple CO with perchlorate or chlorate under anaerobic conditions with or without nitrate as an inducer for nitrate reductase, which serves as a perchlorate reductase in extreme halophiles. In the presence of perchlorate, CO concentrations were reduced to levels well below those found in Mars' atmosphere. This indicates that CO could contribute to the survival of microbial populations in hydrated salt formations or brines if water activities are suitably permissive.

Crystal structure of [(1,2,3,4,11,12-η)-anthracene]tris­(tri­methyl­stann­yl)cobalt(III)

PubMed Central

Brennessel, William W.; Ellis, John E.

2014-01-01

The asymmetric unit of the title structure, [Co(η6-C14H10){Sn(CH3)3}3], contains two independent mol­ecules. Each anthracene ligand is η6-coordinating to a CoIII cation and is nearly planar [fold angles of 5.4 (3) and 9.7 (3)°], as would be expected for its behaving almost entirely as a donor to a high-oxidation-state metal center. The slight fold in each anthracene ligand gives rise to slightly longer Co—C bond lengths to the ring junction carbon atoms than to the other four. Each CoIII cation is further coordinated by three Sn(CH3)3 ligands, giving each mol­ecule a three-legged piano-stool geometry. In each of the two independent mol­ecules, the trio of SnMe3 ligands are modeled as disordered over two positions, rotated by approximately 30%, such that the C atoms nearly overlap. In one mol­ecule, the disorder ratio refined to 0.9365 (8):0.0635 (8), while that for the other refined to 0.9686 (8):0.0314 (8). The mol­ecules are well separated, and thus no significant inter­molecular inter­actions are observed. The compound is of inter­est as the first structure report of an η6-anthracene cobalt(III) complex. PMID:25484731

Effect of ionic strength on the thermodynamic characteristics of complexation between Fe(III) ion and nicotinamide in water-ethanol and water-dimethyl sulfoxide mixtures

NASA Astrophysics Data System (ADS)

Gamov, G. A.; Grazhdan, K. V.; Gavrilova, M. A.; Dushina, S. V.; Sharnin, V. A.; Baranski, A.

2013-06-01

Solutions of iron(III) perchlorate in water, water-ethanol, and water-dimethyl sulfoxide solvents (x_{H_2 O} = 0.7 and 0.25 mole fractions) at ionic strength values I = 0.1, 0.25, and 0.5 are studied by IR spectroscopy. Analysis of the absorption bands of perchlorate ion shows that it does not participate in association processes. It is demonstrated that in the range of ionic strength values between 0 and 0.5 (NaClO4), it affects neither the results from potentiometric titration to determine the stability constants of the iron(III)-nicotinamide complex nor the thermal effects of complexation determined via direct calorimetry in a binary solvent containing 0.3 mole fractions (m.f.) of a non-aqueous component.

Coordination chemistry of 6-thioguanine derivatives with cobalt: toward formation of electrical conductive one-dimensional coordination polymers.

PubMed

Amo-Ochoa, Pilar; Alexandre, Simone S; Hribesh, Samira; Galindo, Miguel A; Castillo, Oscar; Gómez-García, Carlos J; Pike, Andrew R; Soler, José M; Houlton, Andrew; Zamora, Félix; Harrington, Ross W; Clegg, William

2013-05-06

In this work we have synthetized and characterized by X-ray diffraction five cobalt complexes with 6-thioguanine (6-ThioGH), 6-thioguanosine (6-ThioGuoH), or 2'-deoxy-6-thioguanosine (2'-d-6-ThioGuoH) ligands. In all cases, these ligands coordinate to cobalt via N7 and S6 forming a chelate ring. However, independently of reagents ratio, 6-ThioGH provided monodimensional cobalt(II) coordination polymers, in which the 6-ThioG(-) acts as bridging ligand. However, for 2'-d-6-ThioGuoH and 6-ThioGuoH, the structure directing effect of the sugar residue gives rise to mononuclear cobalt complexes which form extensive H-bond interactions to generate 3D supramolecular networks. Furthermore, with 2'-d-6-ThioGuoH the cobalt ion remains in the divalent state, whereas with 6-ThioGuoH oxidation occurs and Co(III) is found. The electrical and magnetic properties of the coordination polymers isolated have been studied and the results discussed with the aid of DFT calculations, in the context of molecular wires.

Perchlorate Data for Streams and Groundwater in Selected Areas of the United States, 2004

USGS Publications Warehouse

Kalkhoff, Stephen J.; Stetson, Sarah J.; Lund, Kris D.; Wanty, Richard B.; Linder, Gregory L.

2010-01-01

This report presents data collected as part of a reconnaissance study to evaluate the occurrence of perchlorate in rivers and streams and in shallow aquifers in selected areas of the United States. Perchlorate, a component in rocket fuels, fireworks, and some explosives is soluble in water and persists in soils and water for long periods. It is biologically active at relatively low-levels in the environment, and has been identified as an endocrine-disrupting chemical. The purpose of this reconnaissance was to determine the occurrence of perchlorate in agricultural areas of the Midwestern and North-Central United States and in arid Central and Western parts of the United States. Samples were collected from 171 sites on rivers and streams and 146 sites from wells during the summer and early fall of 2004. Samples were collected from surface-water sites in 19 states and from wells in 5 states. Perchlorate was detected in samples collected in 15 states and was detected in 34 of 182 samples from rivers and streams and in 64 of 148 groundwater samples at concentrations equal to or greater than 0.4 micrograms per liter. Perchlorate concentrations were 1.0 micrograms per liter or greater in surface-water samples from seven states and in groundwater samples in four states. Only one surface-water and one groundwater sample had concentrations greater than 5.0 micrograms per liter. Perchlorate concentrations in followup samples collected from 1 to 3 months after the initial sample were unchanged at four of five stream sites.

Effects of prolonged exposure to perchlorate on thyroid and reproductive function in zebrafish

USGS Publications Warehouse

Mukhi, S.; Patino, R.

2007-01-01

The objectives of this study were to determine the effects of prolonged exposure to perchlorate on (1) thyroid status and reproductive performance of adult zebrafish (Danio rerio) and (2) F1 embryo survival and early larval development. Using a static-renewal procedure, mixed sex populations of adult zebrafish were exposed to 0, 10, and 100 mg/l nominal concentrations of waterborne perchlorate for 10 weeks. Thyroid histology was qualitatively assessed, and females and males were separated and further exposed to their respective treatments for six additional weeks. Eight females in each tank replicate (n = 3) were paired weekly with four males from the same respective treatment, and packed-egg (spawn) volume (PEV) was measured each of the last five weeks. At least once during weeks 14-16 of exposure, other end points measured included fertilization rate, fertilized egg diameter, hatching rate, standard length, and craniofacial development of 4-day-postfertilization larvae and thyroid hormone content of 3.5-h embryos and of exposed mothers. At 10 weeks of exposure, perchlorate at both concentrations caused thyroidal hypertrophy and colloid depletion. A marked reduction in PEV was observed toward the end of the 6-week spawning period, but fertilization and embryo hatching rates were unaffected. Fertilized egg diameter and larval length were increased by parental exposure to perchlorate. Larval head depth was unaffected but the forward protrusion of the lower jaw-associated cartilage complexes, Meckel's and ceratohyal, was decreased. Exposure to both concentrations of perchlorate inhibited whole-body thyroxine content in mothers and embryos, but triiodothyronine content was unchanged. In conclusion, prolonged exposure of adult zebrafish to perchlorate not only disrupts their thyroid endocrine system but also impairs reproduction and influences early F1 development. ?? 2007 Oxford University Press.

Validation of Chlorine and Oxygen Isotope Ratio Analysis To Differentiate Perchlorate Sources and To Document Perchlorate Biodegradation

DTIC Science & Technology

2013-05-31

2000; p 529. 16. Schlosser, P.; Stute, M.; Dörr, H.; Sonntag, C.; Münnich, K. O., Tritium/3He dating of shallow groundwater. Earth and Planetary...57  5.3.2 Groundwater Dating ...Perchlorate ................ 91  7.1.4 Groundwater Dating and Other Supporting Data .......................................... 94  7.1.5 Summary of

Concurrent microbial reduction of high concentrations of nitrate and perchlorate in an ion exchange membrane bioreactor.

PubMed

Fox, Shalom; Bruner, Tali; Oren, Yoram; Gilron, Jack; Ronen, Zeev

2016-09-01

We investigated effective simultaneous removal of high loads of nitrate and perchlorate from synthetic groundwater using an ion exchange membrane bioreactor (IEMB). The aim of this research was to characterize both transport aspects and biodegradation mechanisms involved in the treatment process of high loads of the two anions. Biodegradation process was proven to be efficient with over 99% efficiency of both perchlorate and nitrate, regardless of their load. The maximum biodegradation rates were 18.3 (mmol m(-2)  h(-1) ) and 5.5 (mmol m(-2)  h(-1) ) for nitrate and perchlorate, respectively. The presence of a biofilm on the bio-side of the membrane only slightly increased the nitrate and perchlorate transmembrane flux as compared to the measured flux during a Donnan dialysis experiment where there is no biodegradation of perchlorate and nitrate in the bio-compartment. The nitrate flux in presence of a biofilm was 18.3 (±1.9) (mmole m(-2)  h(-1) ), while without the biofilm, the flux was 16.9 (±1.5) (mmole m(-2)  h(-1) ) for the same feed inlet nitrate concentration of 4 mM. The perchlorate transmembrane flux increased similarly by an average of 5%. Samples of membrane biofilm and suspended bacteria from the bio-reactor were analyzed for diversity and abundance of the perchlorate and nitrate reducing bacteria. Klebsiella oxytoca, known as a glycerol fermenter, accounted for 70% of the suspended bacteria. In contrast, perchlorate and nitrate reducing bacteria predominated in the biofilm present on the membrane. These results are consistent with our proposed two stage biodegradation mechanism where glycerol is first fermented in the suspended phase of the bio-reactor and the fermentation products drive perchlorate and nitrate bio-reduction in the biofilm attached to the membrane. These results suggest that the niche exclusion of microbial populations in between the reactor and membrane is controlled by the fluxes of the electron donors and

Possible Detection of Perchlorates by the Sample Analysis at Mars (SAM) Instrument: Comparison with Previous Missions

NASA Technical Reports Server (NTRS)

Navarro-Gonzalex, Rafael; Sutter, Brad; Archer, Doug; Ming, Doug; Eigenbrode, Jennifer; Franz, Heather; Glavin, Daniel; McAdam, Amy; Stern, Jennifer; McKay, Christopher;

Pediatric neurobehavioral diseases in Nevada counties with respect to perchlorate in drinking water: an ecological inquiry.

PubMed

Chang, Soju; Crothers, Carol; Lai, Shenghan; Lamm, Steven

2003-10-01

Contamination of drinking water with perchlorate, a known thyrotropic agent, has been demonstrated in areas in the western United States. The health consequences of that exposure have been studied, particularly in the State of Nevada. Previous studies in Nevada, comparing the area with perchlorate in the drinking water and the areas without perchlorate in the drinking water, have found no difference in neonatal thyroxine (T(4)) or thyrotropin (TSH) levels, or in the prevalences of thyroid diseases and thyroid cancer. This same study design has now been applied to the major neurobehavioral diseases of childhood (i.e., attention deficit-hyperactivity disorder (ADHD) and autism) and to school performance in order to determine whether those conditions are more frequent in the area with perchlorate-contaminated water. Medical services data on ADHD and autism were obtained from the Nevada Medicaid system for the period of January 1, 1996, to December 31, 2000, with county of residence used as the basis for residential information. Analyses of fourth-grade school performance results for two recent time periods came from the state government. Perchlorate concentrations in drinking water had been determined by local water authorities. ADHD and autism rates for the area with perchlorate in the drinking water (Clark County) were calculated and compared with the rates for the other areas in the state, as were fourth-grade school performances. Analysis of the data from the Nevada Medicaid program shows that the rates for ADHD and for autism in the area where perchlorate was in the drinking water did not exceed the rates in those areas where there was no perchlorate contamination in the drinking water. Fourth-grade standardized test results for students in Clark County were not different from those of the remainder of the state. This ecological study of children in the exposure area did not find evidence of an increased risk of either ADHD or of autism caused by perchlorate

High-Nitrogen-Based Pyrotechnics: Development of Perchlorate-Free Green-Light Illuminants for Military and Civilian Applications

DTIC Science & Technology

2012-01-01

Table 1. Magnesium served as the main fuel in the formulation, barium nitrate and potassium per- chlorate served as the oxidizers, and dechlorane plus...course of the investigation needed to be changed. Although the initial investigation set out to remove potassium per- chlorate oxidizer from the M195 HHS...become a concern of the US Department of Defense is the “perchlorate issue.” Potassium perchlorate and ammonium perchlorate oxidizers, once believed to be

Evidence of Influence of Human Activities and Volcanic Eruptions on Environmental Perchlorate from a 300-Year Greenland Ice Core Record.

PubMed

Cole-Dai, Jihong; Peterson, Kari Marie; Kennedy, Joshua Andrew; Cox, Thomas S; Ferris, David G

2018-06-26

A 300-year (1700-2007) chronological record of environmental perchlorate, reconstructed from high-resolution analysis of a central Greenland ice core, shows that perchlorate levels in the post-1980 atmosphere were two-to-three times those of the pre-1980 environment. While this confirms recent reports of increased perchlorate in Arctic snow since 1980 compared with the levels for the prior decades (1930-1980), the longer Greenland record demonstrates that the Industrial Revolution and other human activities, which emitted large quantities of pollutants and contaminants, did not significantly impact environmental perchlorate, as perchlorate levels remained stable throughout the eighteenth, nineteenth, and much of the twentieth centuries. The increased levels since 1980 likely result from enhanced atmospheric perchlorate production, rather than from direct release from perchlorate manufacturing and applications. The enhancement is probably influenced by the emission of organic chlorine compounds in the last several decades. Prior to 1980, no significant long-term temporal trends in perchlorate concentration are observed. Brief (a few years) high concentration episodes appear frequently over an apparently stable and low background (~1 ng kg‒1). Several such episodes coincide in time with large explosive volcanic eruptions including the 1912 Novarupta/Katmai eruption in Alaska. It appears that atmospheric perchlorate production is impacted by large eruptions in both high and low latitudes, but not by small eruptions and non-explosive degassing.

Effects of cobalt precursor on pyrolyzed carbon-supported cobalt-polypyrrole as electrocatalyst toward oxygen reduction reaction

PubMed Central

2013-01-01

A series of non-precious metal electrocatalysts, namely pyrolyzed carbon-supported cobalt-polypyrrole, Co-PPy-TsOH/C, are synthesized with various cobalt precursors, including cobalt acetate, cobalt nitrate, cobalt oxalate, and cobalt chloride. The catalytic performance towards oxygen reduction reaction (ORR) is comparatively investigated with electrochemical techniques of cyclic voltammogram, rotating disk electrode and rotating ring-disk electrode. The results are analyzed and discussed employing physiochemical techniques of X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, elemental analysis, and extended X-ray absorption fine structure. It shows that the cobalt precursor plays an essential role on the synthesis process as well as microstructure and performance of the Co-PPy-TsOH/C catalysts towards ORR. Among the studied Co-PPy-TsOH/C catalysts, that prepared with cobalt acetate exhibits the best ORR performance. The crystallite/particle size of cobalt and its distribution as well as the graphitization degree of carbon in the catalyst greatly affects the catalytic performance of Co-PPy-TsOH/C towards ORR. Metallic cobalt is the main component in the active site in Co-PPy-TsOH/C for catalyzing ORR, but some other elements such as nitrogen are probably involved, too. PMID:24229351

PERCHLORATE CHEMISTRY: IMPLICATIONS FOR ANALYSIS AND REMEDIATION

EPA Science Inventory

Since the discovery of perchlorate in the ground and surface waters of several western states, there has been increasing interest in the health effects resulting from chronic exposure to low (ppb) levels. With this concern has come a need to investigate technologies that might be...

National Cost Implications of a Potentional Perchlorate Regulation

EPA Pesticide Factsheets

In this study, a screening level cost assessment was conducted to evaluate the national cost implications of five potential regulatory levels for perchlorate in drinking water 4, 6, 12, 18, and 24 ?g/L.

Perchlorate Radiolysis on Mars and the Origin of Martian Soil Reactivity

PubMed Central

Martucci, Hana F.H.; Miller, Stephanie R.; Bryson, Charles E.; Grunthaner, Frank J.; Grunthaner, Paula J.

2013-01-01

Abstract Results from the Viking biology experiments indicate the presence of reactive oxidants in martian soils that have previously been attributed to peroxide and superoxide. Instruments on the Mars Phoenix Lander and the Mars Science Laboratory detected perchlorate in martian soil, which is nonreactive under the conditions of the Viking biology experiments. We show that calcium perchlorate exposed to gamma rays decomposes in a CO2 atmosphere to form hypochlorite (ClO−), trapped oxygen (O2), and chlorine dioxide (ClO2). Our results show that the release of trapped O2 (g) from radiation-damaged perchlorate salts and the reaction of ClO− with amino acids that were added to the martian soils can explain the results of the Viking biology experiments. We conclude that neither hydrogen peroxide nor superoxide is required to explain the results of the Viking biology experiments. Key Words: Mars—Radiolysis—Organic degradation—in situ measurement—Planetary habitability and biosignatures. Astrobiology 13, 515–520. PMID:23746165

Accumulation of perchlorate in aquatic and terrestrial plants at a field scale.

PubMed

Tan, Kui; Anderson, Todd A; Jones, Matthew W; Smith, Philip N; Jackson, W Andrew

2004-01-01

Previous laboratory-scale studies have documented perchlorate ClO(-)(4) uptake by different plant species, but less information is available at field scale, where ClO(-)(4) uptake may be affected by environmental conditions, such as distance to streams or shallow water tables, exposure duration, and species. This study examined uptake of ClO(-)(4) in smartweed (Polygonum spp.) and watercress (Nasturtium spp.) as well as more than forty trees, including ash (Fraxinus greggii A. Gray), chinaberry (Melia azedarach L.), elm (Ulmus parvifolia Jacq.), willow (Salix nigra Marshall), mulberry [Broussonetia papyrifera (L.) Vent.], and hackberry (Celtis laevigata Willd.) from multiple streams surrounding a perchlorate-contaminated site. Results indicate a large potential for ClO(-)(4) accumulation in aquatic and terrestrial plants, with ClO(-)(4) concentration in plant tissues approximately 100 times higher than that in bulk water. Perchlorate accumulation in leaves of terrestrial plants was also dependent on species, with hackberry, willow, and elm having a strong potential to accumulate ClO(-)(4). Generally, trees located closer to the stream had a higher ClO(-)(4) accumulation than trees located farther away from the stream. Seasonal leaf sampling of terrestrial plants indicated that ClO(-)(4) accumulation also was affected by exposure duration, with highest accumulation observed in the late growing cycle, although leaf concentrations for a given tree were highly variable. Perchlorate may be re-released into the environment via leaching and rainfall as indicated by lower perchlorate concentrations in collected leaf litter. Information obtained from this study will be helpful to understand the fate of ClO(-)(4) in macrophytes and natural systems.

Probability of detecting perchlorate under natural conditions in deep groundwater in California and the Southwestern United States

USGS Publications Warehouse

Fram, Miranda S.; Belitz, Kenneth

2011-01-01

We use data from 1626 groundwater samples collected in California, primarily from public drinking water supply wells, to investigate the distribution of perchlorate in deep groundwater under natural conditions. The wells were sampled for the California Groundwater Ambient Monitoring and Assessment Priority Basin Project. We develop a logistic regression model for predicting probabilities of detecting perchlorate at concentrations greater than multiple threshold concentrations as a function of climate (represented by an aridity index) and potential anthropogenic contributions of perchlorate (quantified as an anthropogenic score, AS). AS is a composite categorical variable including terms for nitrate, pesticides, and volatile organic compounds. Incorporating water-quality parameters in AS permits identification of perturbation of natural occurrence patterns by flushing of natural perchlorate salts from unsaturated zones by irrigation recharge as well as addition of perchlorate from industrial and agricultural sources. The data and model results indicate low concentrations (0.1-0.5 μg/L) of perchlorate occur under natural conditions in groundwater across a wide range of climates, beyond the arid to semiarid climates in which they mostly have been previously reported. The probability of detecting perchlorate at concentrations greater than 0.1 μg/L under natural conditions ranges from 50-70% in semiarid to arid regions of California and the Southwestern United States to 5-15% in the wettest regions sampled (the Northern California coast). The probability of concentrations above 1 μg/L under natural conditions is low (generally <3%).

Contact Electrification of Regolith Particles and Chloride Electrolysis: Synthesis of Perchlorates on Mars.

PubMed

Tennakone, K

2016-10-01

Contact electrification of chloride-impregnated martian regolith particles due to eolian agitation and moisture condensation on coalesced oppositely charged grains may lead to spontaneous electrolysis that generates hypochlorite, chlorite, chlorate, and perchlorate with a concomitant reduction of water to hydrogen. This process is not curtailed even if moisture condenses as ice because chloride ionizes on the surface of ice. Limitations dictated by potentials needed for electrolysis and breakdown electric fields enable estimation of the required regolith grain size. The estimated dimension turns out to be of the same order of magnitude as the expected median size of martian regolith, and a simple calculation yields the optimum rate of perchlorate production. Key Words: Mars oxidants-Perchlorate-Dust electrification-Electrolysis. Astrobiology 16, 811-816.

Evaluation of Alternative Causes of Widespread, Low Concentration Perchlorate Impacts to Groundwater

DTIC Science & Technology

2008-07-01

burning ceased, the residue and remaining slag were collected. 5. The slag was weighed in order to approximate the extent to which the flare had...with triple distilled, deionized water. 7. The washings and slag from each flare were placed in separate round-bottom flasks and stirred for ten...remaining was 0.027% on average or 99.97% of the original perchlorate was consumed (Table 3.3). Nevertheless, a slag containing elevated perchlorate

The colloidal thyroxine (T4) ring as a novel biomarker of perchlorate exposure in the African clawed frog Xenopus laevis

USGS Publications Warehouse

Hu, F.; Sharma, Bibek; Mukhi, S.; Patino, R.; Carr, J.A.

2006-01-01

The purpose of this study was to determine if changes in colloidal thyroxine (T4) immunoreactivity can be used as a biomarker of perchlorate exposure in amphibian thyroid tissue. Larval African clawed frogs (Xenopus laevis) were exposed to 0, 1, 8, 93, and 1131 ??g perchlorate/l for 38 and 69 days to cover the normal period of larval development and metamorphosis. The results of this study confirmed the presence of an immunoreactive colloidal T4 ring in thyroid follicles of X. laevis and demonstrated that the intensity of this ring is reduced in a concentration-dependent manner by perchlorate exposure. The smallest effective concentration of perchlorate capable of significantly reducing colloidal T4 ring intensity was 8 ??g perchlorate/l. The intensity of the immunoreactive colloidal T4 ring is a more sensitive biomarker of perchlorate exposure than changes in hind limb length, forelimb emergence, tail resorption, thyrocyte hypertrophy, or colloid depletion. We conclude that the colloidal T4 ring can be used as a sensitive biomarker of perchlorate-induced thyroid disruption in amphibians. ?? Copyright 2006 Oxford University Press.

Effects of water temperature on perchlorate toxicity to the thyroid and reproductive system of Oryzias latipes.

PubMed

Lee, Sangwoo; Ji, Kyunghee; Choi, Kyungho

2014-10-01

Water temperature is expected to increase in many parts of the world due to global climate change. The change in water temperature may affect ecosystems through alterations of the chemical properties or by affecting the susceptibility of organisms. Perchlorate can disrupt thyroid function of an organism by inhibiting iodide uptake. In the present study, the effect of water temperature on perchlorate toxicity was evaluated using Japanese medaka (Oryzias latipes). Pairs of adult medaka fish were exposed to a sublethal concentration of sodium perchlorate (100mg/L) and a control, at a 'low' (26°C), 'medium' (29°C) or 'high' water temperature (33°C) for seven days. The effects of the water temperature on reproduction, thyroid hormones and cortisol concentrations were determined. Transcription of several genes related to thyroid function and stress were also investigated. Significant down-regulation of thyroid hormone receptor alpha (THR-α) and beta (THR-β) transcripts and up-regulation of deiodinase 2 (DIO2) transcripts were observed in the fish exposed to perchlorate. Thyroxine (T4) concentrations were decreased, while triiodothyronine (T3) levels remained constant following exposure to perchlorate, and this effect became more pronounced under the high water temperature conditions (33°C). Up-regulation of the DIO2 gene may explain these observations. The total number of spawned eggs decreased slightly as the water temperature increased, and this reduction became significant when fish were exposed to perchlorate. Our observations indicate that exposure to perchlorate could affect thyroid function and overall reproductive fitness, and these effects could be aggravated under high water temperatures. Copyright © 2014 Elsevier Inc. All rights reserved.

Radioactive cobalt removal from Salem liquid radwaste with cobalt selective media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maza R.; Wilson, J.A.; Hetherington, R.

This paper reports results of benchtop tests using ion exchange material to selectively remove radioactive cobalt from high conductivity liquid radwaste at the Salem Nuclear Generating Station. The purpose of this test program is to reduce the number of curies in liquid releases without increasing the solid waste volume. These tests have identified two cobalt selective materials that together remove radioactive cobalt more effectively than the single component currently used. All test materials were preconditioned by conversion to the divalent calcium or sulfate form to simulate chemically exhausted media.

PERFORMANCE OF POLYVINYL ALCOHOL GEL COLUMNS ON THE ION CHROMATOGRAPHIC DETERMINATION OF PERCHLORATE IN FERTILIZERS

EPA Science Inventory

Interest in possible sources of perchlorate (ClO4-) that could lead to environmental release has been heightened since the EPA placed this anion on its Contaminant Candidate List (CCL) for drinking water. Besides its association with defense and aerospace activities, perchlorate ...

MICROSCALE EXTRACTION OF PERCHLORATE IN DRINKING WATER WITH LOW LEVEL DETECTION BY ELECTROSPRAY-MASS SPECTROMETRY.

EPA Science Inventory

Improper treatment and disposal of perchlorate can be an environmental hazard in regions where solid rocket motors are used, tested, or stored. The solubility and mobility of perchlorate lends itself to ground water contamination, and some of these sources are used for drinking ...

REMOTE SENSING OF PERCHLORATE EFFECTS ON SALT CEDAR PRELIMINARY RESULTS FROM THE LAS VEGAS WASH

EPA Science Inventory

Sodium Perchlorate and ammonium Perchlorate, major components of solid rocket fuel, have been manufactured in the Las Vegas Valley immediately up gradient from the Las Vegas Wash, since 1945 and 1956, respectively. Measurements of emerging ground water quality in the vici...

The Nitrate/Perchlorate Ratio on Mars As an Indicator for Habitability

NASA Astrophysics Data System (ADS)

Stern, J. C.; Sutter, B.; McKay, C. P.; Navarro-Gonzalez, R.; Freissinet, C.; Conrad, P. G.; Mahaffy, P. R.; Archer, P. D., Jr.; Ming, D. W.; Martín-Torres, J.; Zorzano, M. P.

2014-12-01

Discovery of indigenous martian nitrogen in Mars surface materials has important implications for habitability and the potential development of a nitrogen cycle at some point in martian history. The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected evolved nitric oxide (NO) gas during pyrolysis of scooped aeolian sediments and drilled mudstone acquired in Gale Crater. The detection of NO suggests an indigenous source of fixed nitrogen, and may indicate a mineralogical sink for atmospheric N2 in the form of nitrate. The ratio of nitrate to oxychlorine species (e.g. perchlorate) may provide insight into the extent of development of a nitrogen cycle on Mars. Nitrate and perchlorate on Earth are geochemically related in arid environments such as the Atacama Desert and the Dry Valleys of Antarctica due to their similar mobilities and deposition mechanisms [1,2]. Here, low NO3-/ClO4- molar ratios (~1000) dominate, in comparison to other places on Earth, where the main nitrate source is biological fixation of N2 to NO3-, and there is no corresponding biological source of perchlorate, resulting in much higher NO3-/ClO4- molar ratios (~10,000). The NO3-/ClO4- molar ratio is estimated to be ~ 0.05 on Mars based on SAM measurements at Gale Crater [3]. The possibility exists that perchlorate brines could leach and increase nitrate concentrations at depth, increasing the martian NO3-/ClO4- ratio in the subsurface. However, it is unknown whether terrestrial NO3-/ClO4- molar ratios could be achieved by this mechanism. Nevertheless, the low NO3-/ClO4- the ratio detected by SAM suggests that N fixation to nitrate on Mars, whether biologically mediated or abiotic, was extremely limited compared to the potentially ongoing abiotic formation and deposition of oxychlorine species on the martian surface. [1] Kounaves, S.P. et al. "Discovery of natural perchlorate in the Antarctic dry valleys and its global implications." ES&T44

Microbial redox processes in deep subsurface environments and the potential application of (per)chlorate in oil reservoirs

PubMed Central

Liebensteiner, Martin G.; Tsesmetzis, Nicolas; Stams, Alfons J. M.; Lomans, Bartholomeus P.

2014-01-01

The ability of microorganisms to thrive under oxygen-free conditions in subsurface environments relies on the enzymatic reduction of oxidized elements, such as sulfate, ferric iron, or CO2, coupled to the oxidation of inorganic or organic compounds. A broad phylogenetic and functional diversity of microorganisms from subsurface environments has been described using isolation-based and advanced molecular ecological techniques. The physiological groups reviewed here comprise iron-, manganese-, and nitrate-reducing microorganisms. In the context of recent findings also the potential of chlorate and perchlorate [jointly termed (per)chlorate] reduction in oil reservoirs will be discussed. Special attention is given to elevated temperatures that are predominant in the deep subsurface. Microbial reduction of (per)chlorate is a thermodynamically favorable redox process, also at high temperature. However, knowledge about (per)chlorate reduction at elevated temperatures is still scarce and restricted to members of the Firmicutes and the archaeon Archaeoglobus fulgidus. By analyzing the diversity and phylogenetic distribution of functional genes in (meta)genome databases and combining this knowledge with extrapolations to earlier-made physiological observations we speculate on the potential of (per)chlorate reduction in the subsurface and more precisely oil fields. In addition, the application of (per)chlorate for bioremediation, souring control, and microbial enhanced oil recovery are addressed. PMID:25225493

Investigation of Perchlorate and Water at the Surface of Mars with Raman Scattering

NASA Astrophysics Data System (ADS)

Nikolakakos, G.; Whiteway, J. A.

2015-12-01

A major accomplishment of the NASA Phoenix Mars mission was the identification of perchlorate (ClO4-) in the regolith by the Wet Chemistry Laboratory instrument. More recently, the Sample Analysis at Mars instrument on the NASA Curiosity Rover detected the presence of perchlorate in Gale Crater, suggesting that it is globally distributed. Perchlorates are of great interest on Mars due to their high affinity for water vapor (deliquescence) as well as their ability to greatly depress the freezing point of water when in solution. This has intriguing biological implications as resulting brines could potentially provide a habitable environment for living organisms. Additionally, it has been speculated that these salts may play a significant role in the hydrological cycle on Mars. A sample of magnesium perchlorate was subjected to the water vapor pressure and temperatures found at the landing site of the Phoenix Mars mission. Laser Raman scattering was applied to detect the onset of deliquescence and provide a relative estimate of the quantity of water taken up and subsequently released by the sample. As the temperature of the sample decreased at the same rate as measured on Mars during the evening, significant uptake of water from the atmosphere was observed to occur prior to the frost point temperature being reached. As the temperature was lowered, water uptake continued as saturation was reached and frost formed on the surface surrounding the perchlorate sample. Freezing of the brine film was observed at the eutectic temperature of -67°C and thawing occurred at a temperature of -62°C.

Poly[[(μ2-acetato-κ3 O,O′:O′)aqua­bis­(μ3-isonicotinato-κ3 O:O′:N)samarium(III)silver(I)] perchlorate

PubMed Central

Zhu, Li-Cai; Zhu, Si-Ming

2011-01-01

The title compound, {[AgSm(C6H4NO2)2(CH3CO2)(H2O)]ClO4}n, is a three-dimensional heterobimetallic complex constructed from a repeating dimeric unit. Only half of the dimeric moiety is found in the asymmetric unit; the unit cell is completed by crystallographic inversion symmetry. The SmIII ion is eight-coordinated by four O atoms of four different isonicotinate ligands, three O atoms of two different acetate ligands, and one O atom of a water mol­ecule. The two-coordinate AgI ion is bonded to two N atoms of two different isonicotinate anions, thereby connecting the disamarium units. In addition, the isonicotinate ligands also act as bridging ligands, generating a three-dimensional network. The coordinated water mol­ecules link the carboxyl­ate group and acetate ligands by O—H⋯O hydrogen bonding. Another O—H⋯O hydrogen bond is observed in the crystal structure. The perchlorate ion is disordered over two sites with site-occupancy factors of 0.560 (11) and 0.440 (11), whereas the methyl group of the acetate ligand is disordered over two sites with site-occupancy factors of 0.53 (5) and 0.47 (5). PMID:22090841

Cobalt metabolism and toxicology--a brief update.

PubMed

Simonsen, Lars Ole; Harbak, Henrik; Bennekou, Poul

2012-08-15

Cobalt metabolism and toxicology are summarized. The biological functions of cobalt are updated in the light of recent understanding of cobalt interference with the sensing in almost all animal cells of oxygen deficiency (hypoxia). Cobalt (Co(2+)) stabilizes the transcriptional activator hypoxia-inducible factor (HIF) and thus mimics hypoxia and stimulates erythropoietin (Epo) production, but probably also by the same mechanism induces a coordinated up-regulation of a number of adaptive responses to hypoxia, many with potential carcinogenic effects. This means on the other hand that cobalt (Co(2+)) also may have beneficial effects under conditions of tissue hypoxia, and possibly can represent an alternative to hypoxic preconditioning. Cobalt is acutely toxic in larger doses, and in mammalian in vitro test systems cobalt ions and cobalt metal are cytotoxic and induce apoptosis and at higher concentrations necrosis with inflammatory response. Cobalt metal and salts are also genotoxic, mainly caused by oxidative DNA damage by reactive oxygen species, perhaps combined with inhibition of DNA repair. Of note, the evidence for carcinogenicity of cobalt metal and cobalt sulfate is considered sufficient in experimental animals, but is as yet considered inadequate in humans. Interestingly, some of the toxic effects of cobalt (Co(2+)) have recently been proposed to be due to putative inhibition of Ca(2+) entry and Ca(2+)-signaling and competition with Ca(2+) for intracellular Ca(2+)-binding proteins. The tissue partitioning of cobalt (Co(2+)) and its time-dependence after administration of a single dose have been studied in man, but mainly in laboratory animals. Cobalt is accumulated primarily in liver, kidney, pancreas, and heart, with the relative content in skeleton and skeletal muscle increasing with time after cobalt administration. In man the renal excretion is initially rapid but decreasing over the first days, followed by a second, slow phase lasting several weeks

PERCHLORATE UPTAKE AND TRANSFORMATION IN AQUATIC PLANTS

EPA Science Inventory

Ammonium Perchlorate (AP) is produced on a large scale by the chemical industry, for a wide range of applications for example, as a strong oxidizing agent in solid rocket fuel. AP must be washed out of the inventory periodically due to its limited shelf-life,and replaced with a f...

Identification of an anaerobic bacterium which reduces perchlorate and chlorate as Wolinella succinogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallace, W.; Attaway, H.

1995-12-31

Perchlorate and chlorate salts are widely used by the chemical, aerospace and defense industries as oxidizers in propellant, explosives and pyrotechnics. The authors have isolated a anaerobic bacterium which is capable of the dissimilatory reduction of both perchlorate and chlorate for energy and growth. Strain HAP-1 is a gram negative, thin rod, non-sporeforming, highly motile strict anaerobe. Antibiotic resistance profiles, utilization of carbon substrates and electron acceptors demonstrated similar physiological characteristics to Wolinella succinogenes. Pairwise comparisons of 16S RNA sequences showed only a 0.75% divergence between strain HAP-1 and W. succinogenes. Physiological, morphological and 16S RRNA sequence data indicate strainmore » HAP-1 is a subspecies of W. succinogenes that can utilize perchlorate and chlorate as terminal electron acceptors.« less

DETERMINATION OF PERCHLORATE IN INDUSTRIAL AND FOODGRADE CHEMICALS

EPA Science Inventory

Perchlorate anion has been found in numerous drinking water supplies at concentrations that recent studies indicate may adversely affect human health. In collaboration with the Office of Ground Water and Drinking Water (OGWDW) and Dionex Corporation, the National Exposure Resea...

THE EFFECTS OF AMMONIUM PERCHLORATE ON THYROIDS (2000)

EPA Science Inventory

In response to recommendations made at the February 1999 external peer review of the December 1998 document entitled, Perchlorate Environmental Contamination: Toxicology Review and Risk Characterization , ...

Cosine (Cobalt Silicide Growth Through Nitrogen-Induced Epitaxy) Process For Epitaxial Cobalt Silicide Formation For High Performance Sha

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Chong Wee; Shin, Chan Soo; Gall, Daniel

A method for forming an epitaxial cobalt silicide layer on a MOS device includes sputter depositing cobalt in an ambient to form a first layer of cobalt suicide on a gate and source/drain regions of the MOS device. Subsequently, cobalt is sputter deposited again in an ambient of argon to increase the thickness of the cobalt silicide layer to a second thickness.

Development of a Screening Tool to Facilitate Technology Transfer of an Innovative Technology to Treat Perchlorate-Contaminated Water

DTIC Science & Technology

2008-03-01

foods such as fruits, vegetables, and beverages (U.S. FDA, 2004). If the U.S. EPA ultimately establishes a drinking water standard for perchlorate...TREAT PERCHLORATE-CONTAMINATED WATER THESIS Daniel A. Craig, Captain, USAF AFIT/GEM/ENV/08-M06 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY...OF AN INNOVATIVE TECHNOLOGY TO TREAT PERCHLORATE- CONTAMINATED WATER THESIS Presented to the Faculty Department of Systems and Engineering

Photoinduced Cobalt(III)-Trifluoromethyl Bond Activation Enables Arene C-H Trifluoromethylation.

PubMed

Harris, Caleb F; Kuehner, Christopher S; Bacsa, John; Soper, Jake D

2018-01-26

Visible-light capture activates a thermodynamically inert Co III -CF 3 bond for direct C-H trifluoromethylation of arenes and heteroarenes. New trifluoromethylcobalt(III) complexes supported by a redox-active [OCO] pincer ligand were prepared. Coordinating solvents, such as MeCN, afford green, quasi-octahedral [( S OCO)Co III (CF 3 )(MeCN) 2 ] (2), but in non-coordinating solvents the complex is red, square pyramidal [( S OCO)Co III (CF 3 )(MeCN)] (3). Both are thermally stable, and 2 is stable in light. But exposure of 3 to low-energy light results in facile homolysis of the Co III -CF 3 bond, releasing . CF 3 radical, which is efficiently trapped by TEMPO . or (hetero)arenes. The homolytic aromatic substitution reactions do not require a sacrificial or substrate-derived oxidant because the Co II by-product of Co III -CF 3 homolysis produces H 2 . The photophysical properties of 2 and 3 provide a rationale for the disparate light stability. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

CO-occurring exposure to perchlorate, nitrate and thiocyanate alters thyroid function in healthy pregnant women

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horton, Megan K., E-mail: megan.horton@mssm.edu; Blount, Benjamin C.; Valentin-Blasini, Liza

Background: Adequate maternal thyroid function during pregnancy is necessary for normal fetal brain development, making pregnancy a critical window of vulnerability to thyroid disrupting insults. Sodium/iodide symporter (NIS) inhibitors, namely perchlorate, nitrate, and thiocyanate, have been shown individually to competitively inhibit uptake of iodine by the thyroid. Several epidemiologic studies examined the association between these individual exposures and thyroid function. Few studies have examined the effect of this chemical mixture on thyroid function during pregnancy Objectives: We examined the cross sectional association between urinary perchlorate, thiocyanate and nitrate concentrations and thyroid function among healthy pregnant women living in New Yorkmore » City using weighted quantile sum (WQS) regression. Methods: We measured thyroid stimulating hormone (TSH) and free thyroxine (FreeT4) in blood samples; perchlorate, thiocyanate, nitrate and iodide in urine samples collected from 284 pregnant women at 12 (±2.8) weeks gestation. We examined associations between urinary analyte concentrations and TSH or FreeT4 using linear regression or WQS adjusting for gestational age, urinary iodide and creatinine. Results: Individual analyte concentrations in urine were significantly correlated (Spearman's r 0.4–0.5, p<0.001). Linear regression analyses did not suggest associations between individual concentrations and thyroid function. The WQS revealed a significant positive association between the weighted sum of urinary concentrations of the three analytes and increased TSH. Perchlorate had the largest weight in the index, indicating the largest contribution to the WQS. Conclusions: Co-exposure to perchlorate, nitrate and thiocyanate may alter maternal thyroid function, specifically TSH, during pregnancy. - Highlights: • Perchlorate, nitrate, thiocyanate and iodide measured in maternal urine. • Thyroid function (TSH and Free T4) measured in maternal

Correlation Analysis of Reactivity in the Photo- and Electro-Reduction of Cobalt(III) Complexes in Binary Organic Solvent/Water Mixtures

NASA Astrophysics Data System (ADS)

Sivaraj, Kumarasamy; Elango, Kuppanagounder P.

2008-08-01

The photo- and electro-reduction of a series of cobalt(III) complexes of the type cis-β - [Co(trien)(RC6H4NH2)Cl]Cl2 with R = H, p-OMe, p-OEt, p-Me, p-Et, p-F, and m-Me has been studied in binary propan-2-ol/water mixtures. The redox potential (E1/2) and photo-reduction quantum yield (ΦCo(II)) data were correlated with solvent and structural parameters with the aim to shed some light on the mechanism of these reactions. The correlation of E1/2 and ΦCo(II) with macroscopic solvent parameters, viz. relative permittivity, indicated that the reactivity is influenced by both specific and non-specific solute-solvent interactions. The Kamlet-Taft solvatochromic comparison method was used to separate and quantify these effects: An increase in the percentage of organic cosolvent in the medium enhances both reduction processes, and there exists a good linear correlation between E1/2 and ΦCo(II), suggesting a similar solvation of the participants in these redox processes.

Developmental exposure to perchlorate alters synaptic transmission in hippocampus of the adult rat: in vivo studies.

EPA Science Inventory

Perchlorate, a contaminant found in food and water supplies throughout the USA, blocks iodine uptake into the thyroid gland to reduce circulating levels of thyroid hormone. Neurological function accompanying developmental exposure to perchlorate was evaluated in the present study...

Controlling the oxidation of bis-tridentate cobalt(ii) complexes having bis(2-pyridylalkyl)amines: ligand vs. metal oxidation.

PubMed

Anjana, S; Donring, S; Sanjib, P; Varghese, B; Murthy, Narasimha N

2017-08-22

Two bis-tridentate chelated cobalt(ii) complexes, which differ in the ligand structure by a methylene group, activate molecular oxygen (O 2 ), and give different oxidation products. The O 2 reaction of [Co II (pepma) 2 ] 2+ (1) with unsymmetrical 2-(2-pyridyl)-N-(2-pyridylmethyl)ethanamine (pepma) results in ligand oxidation, to the corresponding Co(ii) imine complex [Co II (pepmi) 2 ] 2+ (2). Contrastingly, the Co(ii) complex [Co II (bpma) 2 ] 2+ (3) of similar symmetrical bis(2-pyridylmethyl)amine (bpma), undergoes metal oxidation, yielding a cobalt(iii) complex, [Co III (bpma) 2 ] 2+ (4). The reversibility of the amine to imine conversion and the stability of the Co(ii) imine complex (2) are investigated. Furthermore, the solution dynamics of Co(ii) complexes are highlighted with the help of paramagnetic 1 H-NMR spectroscopy.

Re: Request for Correction: Drinking Water: Determination on Perchlorate

EPA Pesticide Factsheets

Request for correction (RFC) of information developed and relied upon by the Environmental Protection Agency (EPA or Agency) to support its determination to regulate perchlorate under the Safe Drinking Water Act (SDWA).

Controlling the misuse of cobalt in horses.

PubMed

Ho, Emmie N M; Chan, George H M; Wan, Terence S M; Curl, Peter; Riggs, Christopher M; Hurley, Michael J; Sykes, David

2015-01-01

Cobalt is a well-established inducer of hypoxia-like responses, which can cause gene modulation at the hypoxia inducible factor pathway to induce erythropoietin transcription. Cobalt salts are orally active, inexpensive, and easily accessible. It is an attractive blood doping agent for enhancing aerobic performance. Indeed, recent intelligence and investigations have confirmed cobalt was being abused in equine sports. In this paper, population surveys of total cobalt in raceday samples were conducted using inductively coupled plasma mass spectrometry (ICP-MS). Urinary threshold of 75 ng/mL and plasma threshold of 2 ng/mL could be proposed for the control of cobalt misuse in raceday or in-competition samples. Results from administration trials with cobalt-containing supplements showed that common supplements could elevate urinary and plasma cobalt levels above the proposed thresholds within 24 h of administration. It would therefore be necessary to ban the use of cobalt-containing supplements on raceday as well as on the day before racing in order to implement and enforce the proposed thresholds. Since the abuse with huge quantities of cobalt salts can be done during training while the use of legitimate cobalt-containing supplements are also allowed, different urinary and plasma cobalt thresholds would be required to control cobalt abuse in non-raceday or out-of-competition samples. This could be achieved by setting the thresholds above the maximum urinary and plasma cobalt concentrations observed or anticipated from the normal use of legitimate cobalt-containing supplements. Urinary threshold of 2000 ng/mL and plasma threshold of 10 ng/mL were thus proposed for the control of cobalt abuse in non-raceday or out-of-competition samples. Copyright © 2014 John Wiley & Sons, Ltd.

Wrought cobalt- base superalloys

NASA Astrophysics Data System (ADS)

Klarstrom, D. L.

1993-08-01

Wrought cobalt-base superalloys are used extensively in gas turbine engines because of their excellent high-temperature creep and fatigue strengths and resistance to hot corrosion attack. In addition, the unique character of the oxide scales that form on some of the alloys provides outstanding resistance to high-temperature sliding wear. This article provides a review of the evolutionary development of wrought cobalt-base alloys in terms of alloy design and physical metallurgy. The topics include solid-so-lution strengthening, carbide precipitation characteristics, and attempts to introduce age hardening. The use of PHACOMP to enhance thermal stability characteristics and the incorporation of rare-earth ele-ments to improve oxidation resistance is also reviewed and discussed. The further development of cobalt-base superalloys has been severely hampered by past political events, which have accentuated the strategic vulnerability of cobalt as a base or as an alloying element. Consequently, alternative alloys have been developed that use little or no cobalt. One such alternative, Haynes® 230TMalloy, is discussed briefly.

Oxygen and chlorine isotopic fractionation during perchlorate biodegradation: Laboratory results and implications for forensics and natural attenuation studies

USGS Publications Warehouse

Sturchio, N.C.; Böhlke, J.K.; Beloso, Abelardo D.; Streger, S.H.; Heraty, L.J.; Hatzinger, P.B.

2007-01-01

Perchlorate is a widespread environmental contaminant having both anthropogenic and natural sources. Stable isotope ratios of O and Cl in a given sample of perchlorate may be used to distinguish its source(s). Isotopic ratios may also be useful for identifying the extent of biodegradation of perchlorate, which is critical for assessing natural attenuation of this contaminant in groundwater. For this approach to be useful, however, the kinetic isotopic fractionations of O and Cl during perchlorate biodegradation must first be determined as a function of environmental variables such as temperature and bacterial species. A laboratory study was performed in which the O and Cl isotope ratios of perchlorate were monitored as a function of degradation by two separate bacterial strains (Azospira suillum JPLRND and Dechlorospirillum sp. FBR2) at both 10??C and 22??C with acetate as the electron donor. Perchlorate was completely reduced by both strains within 280 h at 22??C and 615 h at 10??C. Measured values of isotopic fractionation factors were ??18O = -36.6 to -29.0??? and ??37Cl = -14.5 to -11.5???, and these showed no apparent systematic variation with either temperature or bacterial strain. An experiment using 18O-enriched water (??18O = +198???) gave results indistinguishable from those observed in the isotopically normal water (??18O = -8.1???) used in the other experiments, indicating negligible isotope exchange between perchlorate and water during biodegradation. The fractionation factor ratio ??18O/??37Cl was nearly invariant in all experiments at 2.50 ?? 0.04. These data indicate that isotope ratio analysis will be useful for documenting perchlorate biodegradation in soils and groundwater. The establishment of a microbial fractionation factor ratio (??18O/??37Cl) also has significant implications for forensic studies. ?? 2007 American Chemical Society.

Contribution of tap water to chlorate and perchlorate intake: a market basket study.

PubMed

Asami, Mari; Yoshida, Nobue; Kosaka, Koji; Ohno, Koichi; Matsui, Yoshihiko

2013-10-01

The contributions of water to total levels of chlorate and perchlorate intake were determined using food and water samples from a market basket study from 10 locations in Japan between 2008 and 2009. Foods were categorized into 13 groups and analyzed along with tap water. The average total chlorate intake was 333 (min. 193-max. 486) μg/day for samples cooked with tap water. The contribution of tap water to total chlorate intake was as high as 47%-58%, although total chlorate intake was less than 32% of the tolerable daily intake, 1500 μg/day for body weight of 50 kg. For perchlorate, daily intake from water was 0.7 (0.1-4.4) μg/day, which is not high compared to the average total intake of 14 (2.5-84) μg/day, while the reference dose (RfD) is 35 μg/day and the provisional maximum tolerable daily intake (PMTDI) is 500 μg/day for body weight of 50 kg. The highest intake of perchlorate was 84 μg/day, where concentrations in foods were high, but not in water. The contribution of water to total perchlorate intake ranged from 0.5% to 22%, while the ratio of highest daily intake to RfD was 240% and that to PMTDI was 17%. Eight baby formulas were also tested--total chlorate and perchlorate intakes were 147 (42-332) μg/day and 1.11 (0.05-4.5) μg/day, respectively, for an ingestion volume of 1 L/day if prepared with tap water. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Graphene-a promising material for removal of perchlorate (ClO4-) from water.

PubMed

Lakshmi, Jothinathan; Vasudevan, Subramanyan

2013-08-01

A batch adsorption process was applied to investigate the removal of perchlorate (ClO4 (-)) from water by graphene. In doing so, the thermodynamic adsorption isotherm and kinetic studies were also carried out. Graphene was prepared by a facile liquid-phase exfoliation. Graphene was characterized by Raman spectroscopy, Fourier-transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscope, and zeta potential measurements. A systematic study of the adsorption process was performed by varying pH, ionic strength, and temperature. The adsorption efficiency of graphene was 99.2 %, suggesting that graphene is an excellent adsorbent for ClO4 (-) removal from water. The rate constants for all these kinetic models were calculated, and the results indicate that second-order kinetics model was well suitable to model the kinetic adsorption of ClO4 (-). Equilibrium data were well described by the typical Langmuir adsorption isotherm. The experimental results showed that graphene is an excellent perchlorate adsorbent with an adsorbent capacity of up to 0.024 mg/g at initial perchlorate concentration of 2 mg/L and temperature of 298 K. Thermodynamic studies revealed that the adsorption reaction was a spontaneous and endothermic process. Graphene removed the perchlorate present in the water and reduced it to a permissible level making it drinkable.

Perchlorate exposure and association with iron homeostasis and other biological functions among NHANES 2005-2008 subjects

EPA Science Inventory

Perchlorate exposure and association with iron homeostasis and other biological functions among NHANES 2005-2008 subjects Schreinemachers DM, Ghio AJ, Cascio WE, Sobus JR. U.S. EPA, RTP, NC, USA Perchlorate (ClO4-), an environmental pollutant, is a known thyroid toxicant and...

Green synthesis of cobalt (II, III) oxide nanoparticles using Moringa Oleifera natural extract as high electrochemical electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Matinise, N.; Mayedwa, N.; Fuku, X. G.; Mongwaketsi, N.; Maaza, M.

2018-05-01

The research work involved the development of a better, inexpensive, reliable, easily and accurate way for the fabrication of Cobalt (II, III) oxide (Co3O4) nanoparticles through a green synthetic method using Moringa Oleifera extract. The electrochemical activity, crystalline structure, morphology, isothermal behaviour and optical properties of Co3O4 nanoparticles were studied using various characterization techniques. The X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS) analysis confirmed the formation of Co3O4 nanoparticles. The pseudo-capacitor behaviour of spinel Co3O4 nanoparticles on Nickel foam electrode was investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) in 3M KOH solution. The CV curve revealed a pairs of redox peaks, indicating the pseudo-capacitive characteristics of the Ni/Co3O4 electrode. EIS results showed a small semicircle and Warburg impedance, indicating that the electrochemical process on the surface electrode is kinetically and diffusion controlled. The charge-discharge results indicating that the specific capacitance Ni/Co3O4 electrode is approximately 1060 F/g at a discharge current density of at 2 A/g.

Design of organic dyes and cobalt polypyridine redox mediators for high-efficiency dye-sensitized solar cells.

PubMed

Feldt, Sandra M; Gibson, Elizabeth A; Gabrielsson, Erik; Sun, Licheng; Boschloo, Gerrit; Hagfeldt, Anders

2010-11-24

Dye-sensitized solar cells (DSCs) with cobalt-based mediators with efficiencies surpassing the record for DSCs with iodide-free electrolytes were developed by selecting a suitable combination of a cobalt polypyridine complex and an organic sensitizer. The effect of the steric properties of two triphenylamine-based organic sensitizers and a series of cobalt polypyridine redox mediators on the overall device performance in DSCs as well as on transport and recombination processes in these devices was compared. The recombination and mass-transport limitations that, previously, have been found to limit the performance of these mediators were avoided by matching the properties of the dye and the cobalt redox mediator. Organic dyes with higher extinction coefficients than the standard ruthenium sensitizers were employed in DSCs in combination with outer-sphere redox mediators, enabling thinner TiO(2) films to be used. Recombination was reduced further by introducing insulating butoxyl chains on the dye rather than on the cobalt redox mediator, enabling redox couples with higher diffusion coefficients and more suitable redox potential to be used, simultaneously improving the photocurrent and photovoltage of the device. Optimization of DSCs sensitized with a triphenylamine-based organic dye in combination with tris(2,2'-bipyridyl)cobalt(II/III) yielded solar cells with overall conversion efficiencies of 6.7% and open-circuit potentials of more than 0.9 V under 1000 W m(-2) AM1.5 G illumination. Excellent performance was also found under low light intensity indoor conditions.

Pharmacokinetics of inorganic cobalt and a vitamin B12 supplement in the Thoroughbred horse: Differentiating cobalt abuse from supplementation.

PubMed

Hillyer, L L; Ridd, Z; Fenwick, S; Hincks, P; Paine, S W

2018-05-01

While cobalt is an essential micronutrient for vitamin B 12 synthesis in the horse, at supraphysiological concentrations, it has been shown to enhance performance in human subjects and rats, and there is evidence that its administration in high doses to horses poses a welfare threat. Animal sport regulators currently control cobalt abuse via international race day thresholds, but this work was initiated to explore means of potentially adding to application of those thresholds since cobalt may be present in physiological concentrations. To devise a scientific basis for differentiation between presence of cobalt from bona fide supplementation and cobalt doping through the use of ratios. Six Thoroughbred horses were given 10 mL vitamin B 12 /cobalt supplement (Hemo-15 ® ; Vetoquinol, Buckingham, Buckinghamshire, UK., 1.5 mg B 12 , 7 mg cobalt gluconate = 983 μg total Co) as an i.v. bolus then an i.v. infusion (15 min) of 100 mg cobalt chloride (45.39 mg Co) 6 weeks later. Pre-and post-administration plasma and urine samples were analysed for cobalt and vitamin B 12 . Urine and plasma samples were analysed for vitamin B 12 using an immunoassay and cobalt concentrations were measured via ICP-MS. Baseline concentrations of cobalt in urine and plasma for each horse were subtracted from their cobalt concentrations post-administration for the PK analysis. Compartmental analysis was used for the determination of plasma PK parameters for cobalt using commercially available software. On administration of a vitamin B 12 /cobalt supplement, the ratio of cobalt to vitamin B 12 in plasma rapidly increased to approximately 3 and then rapidly declined below a ratio of 1 and then back to near baseline over the next week. On administration of 100 mg cobalt chloride, the ratio initially exceeded 10 in plasma and then declined with the lower 95% confidence interval remaining above a ratio of 1 for 7 days. For two horses with extended sampling, the plasma ratio remained above one for

PERCHLORATE ENVIRONMENTAL CONTAMINATION: TOXICOLOGICAL REVIEW AND RISK CHARACTERIZATION BASED ON EMERGING INFORMATION (EXTERNAL REVIEW DRAFT) 1998

EPA Science Inventory

Perchlorate (ClO4-) is an anion that originates as a contaminant in ground water and surface waters from the dissolution of ammonium, potassium, magnesium, or sodium salts. Because perchlorate is nonlabile kinetically (i.e., the reduction of the central chlorine atom occurs extre...

Dielectric response of crystalline tris(acetylacetonato)cobalt(III) films grown on Si substrate for low- k dielectric applications

NASA Astrophysics Data System (ADS)

Dakhel, A. A.; Ali-Mohamed, A. Y.

2008-01-01

Thin films of the complex tris(acetylacetonato)cobalt(III) [abb. Co(acac) 3] were deposited in vacuum on glass and p-Si substrates for optical and dielectric studies. The samples were characterised by X-ray diffraction and fluorescence methods as well as optical absorption spectroscopy. The prepared films show a polycrystalline of monoclinic P2 1/ c structure. The optical absorption spectrum of the prepared film was not exactly fit to that of the molecular one. The energy of the optical absorption onset of the Co(acac) 3 film was calculated by using usual solid-state methods. For electrical measurements on the complex as insulator, samples in the form of metal-insulator-semiconductor (MIS) structure were prepared and characterised by measurement of the capacitance as a function of gate voltage at 1 MHz. The frequency dependence of the complex dielectric constant of the complex was studied in the frequency range (1-1000 kHz) in the temperature range (294-323 K). The experimental results were analysed in the framework of Debye single relaxation model. Generally, the present study shows that a film of complex Co(acac) 3 grown on Si substrate is a promising candidate for low- k dielectric applications, it displays low- k value around 1.7 at high frequencies.

Monitored Natural Attenuation of Perchlorate in Groundwater

DTIC Science & Technology

2010-09-01

has been used for industrial purposes, such as fireworks manufacturing, munitions production, pesticide production, and research and manufacturing of...Field Services Division, Washington, DC, August 2006. Hunter, W.J. 2002. Bioremediation of Chlorate or Perchlorate Contaminated Water Using ...5.2.2.1 A-82 Pump-and-Treat System ................................................ 20 5.2.2.2 In Situ Bioremediation Pilot Test

Light and variable 37Cl/35Cl ratios in rocks from Gale Crater, Mars: Possible signature of perchlorate

NASA Astrophysics Data System (ADS)

Farley, K. A.; Martin, P.; Archer, P. D.; Atreya, S. K.; Conrad, P. G.; Eigenbrode, J. L.; Fairén, A. G.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Malespin, C.; Ming, D. W.; Navarro-Gonzalez, R.; Sutter, B.

2016-03-01

Cl isotope ratios measured on HCl thermally evolved from as-yet-unknown phases in sedimentary rocks and sand in Gale Crater provide unexpected insights to the Martian surficial Cl cycle. The seven samples yield δ37Cl values ranging from - 1 ± 25 ‰ to - 51 ± 5 ‰. Five analyses from two samples of the Sheepbed mudstone (Yellowknife Bay study area) are analytically indistinguishable with a mean δ37Cl of - 11 ± 7 ‰ (1 σ). In contrast, four mudstones/sandstones from the Kimberley and Pahrump study areas also yielded indistinguishable ratios, but with a mean δ37Cl of - 43 ± 6 ‰. The Rocknest sand deposit gave a highly uncertain δ37Cl value of - 7 ± 44 ‰. These light and highly variable δ37Cl values are unique among known solar system materials. Two endmember models are offered to account for these observations, and in both, perchlorate, with its extreme ability to fractionate Cl isotopes, is critical. In the first model, SAM is detecting HCl from an oxychlorine compound (e.g., perchlorate) produced from volcanic gas emissions by atmospheric chemical reactions. Similar reactions in Earth's atmosphere may be responsible for the isotopically lightest known Cl outside of this study, in perchlorate from the Atacama Desert. Some of the Gale Crater δ37Cl values are more negative than those in Atacama perchlorate, but because reaction mechanisms and associated fractionation factors are unknown, it is impossible to assess whether this difference is prohibitive. If the negative δ37Cl signal is produced in this fashion, the isotopic variability among samples could arise either from variations in the relative size of the reactant chloride and product perchlorate reservoirs, or from variations in the fraction of perchlorate reduced back to chloride after deposition. Such reduction strongly enriches 37Cl in the residual perchlorate. Perchlorate reduction alone offers an alternative endmember model that can explain the observed data if SAM measured HCl derived

Catalytic destruction of perchlorate in ferric chloride and hydrochloric acid solution with control of temperature, pressure and chemical reagents

DOEpatents

Gu, Baohua; Cole, David R.; Brown, Gilbert M.

2004-10-05

A method is described to decompose perchlorate in a FeCl.sub.3 /HCl aqueous solution such as would be used to regenerate an anion exchange resin used to remove perchlorate. The solution is mixed with a reducing agent, preferably an organic alcohol and/or ferrous chloride, and can be heated to accelerate the decomposition of perchlorate. Lower temperatures may be employed if a catalyst is added.

Preparation of monolayers of [MnIII 6CrIII]3+ single-molecule magnets on HOPG, mica and silicon surfaces and characterization by means of non-contact AFM

NASA Astrophysics Data System (ADS)

Gryzia, Aaron; Predatsch, Hans; Brechling, Armin; Hoeke, Veronika; Krickemeyer, Erich; Derks, Christine; Neumann, Manfred; Glaser, Thorsten; Heinzmann, Ulrich

2011-08-01

We report on the characterization of various salts of [ Mn III 6 Cr III ] 3+ complexes prepared on substrates such as highly oriented pyrolytic graphite (HOPG), mica, SiO2, and Si3N4. [ Mn III 6 Cr III ] 3+ is a single-molecule magnet, i.e., a superparamagnetic molecule, with a blocking temperature around 2 K. The three positive charges of [ Mn III 6 Cr III ] 3+ were electrically neutralized by use of various anions such as tetraphenylborate (BPh4 -), lactate (C3H5O3 -), or perchlorate (ClO4 -). The molecule was prepared on the substrates out of solution using the droplet technique. The main subject of investigation was how the anions and substrates influence the emerging surface topology during and after the preparation. Regarding HOPG and SiO2, flat island-like and hemispheric-shaped structures were created. We observed a strong correlation between the electronic properties of the substrate and the analyzed structures, especially in the case of mica where we observed a gradient in the analyzed structures across the surface.

Silver nanoplate-decorated copper wire for the on-site microextraction and detection of perchlorate using a portable Raman spectrometer.

PubMed

Zhu, Sha; Zhang, Xiaoli; Cui, Jingcheng; Shi, Yu-E; Jiang, Xiaohong; Liu, Zhen; Zhan, Jinhua

2015-04-21

Perchlorate, which causes health concerns because of its effects on the thyroid function, is highly soluble and mobile in the environment. In this study, diethyldithiocarbamate (DDTC)-modified silver nanoplates were fabricated on a copper wire to perform the on-site microextraction and detection of perchlorate. This fiber could be inserted into water or soil to extract perchlorate through electrostatic interaction and then can be detected by a portable Raman spectrometer, owing to its surface-enhanced Raman (SERS) activity. A relatively stable vibrational mode (δ(HCH)(CH3), (CH2)) of DDTC at 1273 cm(-1) was used as an internal standard, which was negligibly influenced by the absorption of ClO4(-). The DDTC-modified Ag/Cu fiber showed high uniformity, good reusability and temporal stability under continuous laser radiation each with an RSD lower than 10%. The qualitative and quantitative detection of perchlorate were also realized. A log-log plot of the normalized SERS intensity against perchlorate concentration showed a good linear relationship. The fiber could be also directly inserted into the perchlorate-polluted soil, and the perchlorate could thereby be detected on site. The detection limit in soil reached 0.081 ppm, which was much lower than the EPA-published safety standard. The recovery of the detection was 105% and comparable with the ion chromatography. This hyphenated method of microextraction with direct SERS detection may find potential application for direct pollutant detection free from complex sample pretreatment.

Evaluation of Potential for Monitored Natural Attenuation of Perchlorate in Groundwater (Indian Head)

DTIC Science & Technology

2010-07-01

United States is through consumption of food (USFDA, 2007). This is a concern because high levels of perchlorate interfere with iodide uptake by the...from more that 50 mg/L to below detection using lactate as a food source; (and) the pH of the aquifer must be buffered to achieve optimal perchlorate...defined by a covering of Nelumbo lutea (American lotus ) which are visible beyond the Subtidal Channel in the photograph Figure 3-14. The main channel

Formation of oxidizing species via irradiation of perchlorates using high-energy electrons and D 2 + ions

NASA Astrophysics Data System (ADS)

Crandall, Parker B.; Gillis-Davis, Jeffrey J.; Kaiser, Ralf-Ingo

2016-10-01

The perchlorate ion (ClO4-) has garnered particular interest in recent years following the discovery of perchlorate salts in the Martian regolith at levels of 0.4-0.6 wt% by the Phoenix lander in 2006 and Mars Science Laboratory's Curiosity rover in 2013. Due to their oxidizing properties, perchlorates are suspected to play a contributing role to the surprising lack of organics on the Martian surface. In this study, magnesium perchlorate hexahydrate (Mg(ClO4)2●6H2O) samples were irradiated with monoenergetic beams of 5 keV electrons and D2+ ions separately, sequentially, and simultaneously to simulate the effects of galactic cosmic ray exposure of perchlorates. The irradiation experiments were carried out under ultra-high vacuum conditions at 50 K, after which the samples were slowly heated to 300 K (0.5 K min-1) while desorbing products were monitored by quadrupole mass spectrometry. In all cases, molecular oxygen (O2) was detected upon the onset of irradiation and again during the warmup phase. In the case of simultaneous irradiation, deuterated water (D2O) and deuterium peroxide (D2O2) were also detected as the sample was heated whereas in the D2+ experiment small amounts of D2O2 was found exclusively. When samples were irradiated sequentially, the production of D2O2 was dependent upon the sample being irradiated with D2+ ions prior to electrons. These experiments show that perchlorates are capable of producing multiple oxidizing agents (O2, D2O2) which may also account for the lack of organics on the Martian surface.

The Impact of Temperature on Anaerobic Biological Perchlorate Treatment

EPA Science Inventory

A 20-month pilot-scale study was conducted to examine the impact of temperature on the performance of an anaerobic biological contactor used to treat perchlorate-contaminated water. The contactor was successfully acclimated with indigenous micro-organisms. Influent temperatures...

In Situ Bioremediation of Perchlorate in Groundwater

DTIC Science & Technology

2009-07-01

Inc. Jay Diebold Shaw Environmental, Inc. Approved for public release; distribution unlimited. Standard Form 298...Rev. 8/98) REPORT DOCUMENTATION PAGE Prescribed by ANSI Std. Z39.18 Form Approved OMB No. 0704-0188 The public reporting burden for this...Approved for Public Release, Distribution is Unlimited None A field demonstration was conducted to evaluate the in situ treatment of perchlorate using a

SURVEY OF BOTTLED WATERS FOR PERCHLORATE BY ELECTROSPRAY IONIZATION MASS SPECTROMETRY (ESI-MS) AND ION CHROMATOGRAPHY (IC)

EPA Science Inventory

Perchlorate has been identified in ground and surface waters around the US, including some that serve as supplies for drinking water. Because perchlorate salts are used as solid oxidants in rockets and ordnance, water contamination may occur near military or aerospace installatio...

Combined effects of perchlorate, thiocyanate, and iodine on thyroid function in the National Health and Nutrition Examination Survey 2007–08

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinmaus, Craig, E-mail: craigs@berkeley.edu; Miller, Mark D., E-mail: ucsfpehsumiller@gmail.com; Cushing, Lara, E-mail: lara.cushing@berkeley.edu

Perchlorate, thiocyanate, and low iodine intake can all decrease iodide intake into the thyroid gland. This can reduce thyroid hormone production since iodide is a key component of thyroid hormone. Previous research has suggested that each of these factors alone may decrease thyroid hormone levels, but effect sizes are small. We hypothesized that people who have all three factors at the same time have substantially lower thyroid hormone levels than people who do not, and the effect of this combined exposure is substantially larger than the effects seen in analyses focused on only one factor at a time. Using datamore » from the 2007–2008 National Health and Nutrition Examination Survey, subjects were categorized into exposure groups based on their urinary perchlorate, iodine, and thiocyanate concentrations, and mean serum thyroxine concentrations were compared between groups. Subjects with high perchlorate (n=1939) had thyroxine concentrations that were 5.0% lower (mean difference=0.40 μg/dl, 95% confidence interval=0.14–0.65) than subjects with low perchlorate (n=2084). The individual effects of iodine and thiocyanate were even smaller. Subjects with high perchlorate, high thiocyanate, and low iodine combined (n=62) had thyroxine concentrations 12.9% lower (mean difference=1.07 μg/dl, 95% confidence interval=0.55–1.59) than subjects with low perchlorate, low thiocyanate, and adequate iodine (n=376). Potential confounders had little impact on results. Overall, these results suggest that concomitant exposure to perchlorate, thiocyanate, and low iodine markedly reduces thyroxine production. This highlights the potential importance of examining the combined effects of multiple agents when evaluating the toxicity of thyroid-disrupting agents. -- Highlights: ► Recent data suggest that essentially everyone in the US is exposed to perchlorate. ► Perchlorate exposure may be associated with lower thyroid hormone levels. ► Some groups may be more susceptible

POLISHING EFFLUENT FROM A PERCHLORATE-REDUCING ANAEROBIC BIOLOGICAL CONTACTOR

EPA Science Inventory

The U.S. Environmental Protection Agency undertook at 3 ½ year pilot-scale biological perchlorate treatment study that included two long (311 and 340 days) examinations of anaerobic effluent polishing. The polishing system consisted of hydrogen peroxide addition and aeration, fo...

Thermal Decomposition of Calcium Perchlorate/Iron-Mineral Mixtures: Implications of the Evolved Oxygen from the Rocknest Eolian Deposit in Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Bruck, A. M.; Sutter, B.; Ming, D. W.; Mahaffy, P.

2014-01-01

A major oxygen release between 300 and 500 C was detected by the Mars Curiosity Rover Sample Analysis at Mars (SAM) instrument at the Rocknest eolian deposit. Thermal decomposition of perchlorate (ClO4-) salts in the Rocknest samples are a possible explanation for this evolved oxygen release. Releative to Na-, K-, Mg-, and Fe-perchlorate, the thermal decomposition of Ca-perchlorate in laboratory experiments released O2 in the temperature range (400-500degC) closest to the O2 release temperatures observed for the Rocknest material. Furthermore, calcium perchlorate could have been the source of Cl in the chlorinated-hydrocarbons species that were detected by SAM. Different components in the Martian soil could affect the decomposition temperature of calcium per-chlorate or another oxychlorine species. This interaction of the two components in the soil could result in O2 release temperatures consistent with those detected by SAM in the Rocknest materials. The decomposition temperatures of various alkali metal perchlorates are known to decrease in the presence of a catalyst. The objective of this work is to investigate catalytic interactions on calcium perchlorate from various iron-bearing minerals known to be present in the Rocknest material

Groundwater movement, recharge, and perchlorate occurrence in a faulted alluvial aquifer in California (USA)

USGS Publications Warehouse

Izbicki, John A.; Teague, Nicholas F.; Hatzinger, Paul B.; Böhlke, John Karl; Sturchio, Neil C.

2015-01-01

Perchlorate from military, industrial, and legacy agricultural sources is present within an alluvial aquifer in the Rialto-Colton groundwater subbasin, 80 km east of Los Angeles, California (USA). The area is extensively faulted, with water-level differences exceeding 60 m across parts of the Rialto-Colton Fault separating the Rialto-Colton and Chino groundwater subbasins. Coupled well-bore flow and depth-dependent water-quality data show decreases in well yield and changes in water chemistry and isotopic composition, reflecting changing aquifer properties and groundwater recharge sources with depth. Perchlorate movement through some wells under unpumped conditions from shallower to deeper layers underlying mapped plumes was as high as 13 kg/year. Water-level maps suggest potential groundwater movement across the Rialto-Colton Fault through an overlying perched aquifer. Upward flow through a well in the Chino subbasin near the Rialto-Colton Fault suggests potential groundwater movement across the fault through permeable layers within partly consolidated deposits at depth. Although potentially important locally, movement of groundwater from the Rialto-Colton subbasin has not resulted in widespread occurrence of perchlorate within the Chino subbasin. Nitrate and perchlorate concentrations at the water table, associated with legacy agricultural fertilizer use, may be underestimated by data from long-screened wells that mix water from different depths within the aquifer.

Complete cobalt recovery from lithium cobalt oxide in self-driven microbial fuel cell - Microbial electrolysis cell systems

NASA Astrophysics Data System (ADS)

Huang, Liping; Yao, Binglin; Wu, Dan; Quan, Xie

2014-08-01

Complete cobalt recovery from lithium cobalt oxide requires to firstly leach cobalt from particles LiCoO2 and then recover cobalt from aqueous Co(II). A self-driven microbial fuel cell (MFC)-microbial electrolysis cell (MEC) system can completely carry out these two processes, in which Co(II) is firstly released from particles LiCoO2 on the cathodes of MFCs and then reduced on the cathodes of MECs which are powered by the cobalt leaching MFCs. A cobalt leaching rate of 46 ± 2 mg L-1 h-1 with yield of 1.5 ± 0.1 g Co g-1 COD (MFCs) and a Co(II) reduction rate of 7 ± 0 mg L-1 h-1 with yield of 0.8 ± 0.0 g Co g-1 COD (MECs), as well as a overall system cobalt yield of 0.15 ± 0.01 g Co g-1 Co can be achieved in this self-driven MFC-MEC system. Coulombic efficiencies reach 41 ± 1% (anodic MFCs), 75 ± 0% (anodic MECs), 100 ± 2% (cathodic MFCs), and 29 ± 1% (cathodic MECs) whereas overall system efficiency averages 34 ± 1%. These results provide a new process of linking MFCs to MECs for complete recovery of cobalt and recycle of spent lithium ion batteries with no external energy consumption.

Crystal structure of tri­hydrogen bis­{[1,1,1-tris­(2-oxido­ethyl­amino­meth­yl)ethane]­cobalt(III)} trinitrate

PubMed Central

Sethi, Waqas; Johannesen, Heini V.; Morsing, Thorbjørn J.; Piligkos, Stergios; Weihe, Høgni

2015-01-01

The title compound, [Co2(L)2]3+·3NO3 − [where L = CH3C(CH2NHCH2CH2OH1/2)3], has been synthesized from the ligand 1,1,1-tris­(2-hy­droxy­ethyl­amino­meth­yl)ethane. The cobalt(III) dimer has an inter­esting and uncommon O—H⋯O hydrogen-bonding motif with the three bridging hy­droxy H atoms each being equally disordered over two positions. In the dimeric trication, the octa­hedrally coordinated CoIII atoms and the capping C atoms lie on a threefold rotation axis. The N atoms of two crystallographically independent nitrate anions also lie on threefold rotation axes. N—H⋯O hydrogen bonding between the complex cations and nitrate anions leads to the formation of a three-dimensional network structure. The compound is a racemic conglomerate of crystals containing either d or l mol­ecules. The crystal used for this study is a d crystal. PMID:26870462

Perchlorate and selected metals in water and soil within Mount Rushmore National Memorial, South Dakota, 2011–15

USGS Publications Warehouse

Hoogestraat, Galen K.; Rowe, Barbara L.

2016-04-14

Mount Rushmore National Memorial is located in the east-central part of the Black Hills area of South Dakota and is challenged to provide drinking water to about 3 million annual visitors and year-round park personnel. An environmental concern to water resources within Mount Rushmore National Memorial has been the annual aerial fireworks display at the memorial for the Independence Day holiday during 1998–2009. A major concern of park management is the contamination of groundwater and surface water by perchlorate, which is used as an oxidizing agent in firework displays. A study by the U.S. Geological Survey, in cooperation with the National Park Service, was completed to characterize the occurrence of perchlorate and selected metals (constituents commonly associated with fireworks) in groundwater and surface water within and adjacent to Mount Rushmore National Memorial during 2011–15. Concentrations of perchlorate and metals in 106 water samples (collected from 6 groundwater sites and 14 surface-water sites) and 11 soil samples (collected from 11 soil sites) are reported.Within the Mount Rushmore National Memorial boundary, perchlorate concentrations were greatest in the Lafferty Gulch drainage basin, ranging from less than 0.20 to 38 micrograms per liter (μg/L) in groundwater samples and from 2.2 to 54 μg/L in surface-water samples. Sites within the Starling Gulch drainage basin also had some evidence of perchlorate contamination, with concentrations ranging from 0.61 to 19 μg/L. All groundwater and surface-water samples within the unnamed tributary to Grizzly Bear Creek drainage basin and reference sites outside the park boundary had concentrations less than 0.20 μg/L. Perchlorate concentrations in samples collected at the 200-foot-deep production well (Well 1) ranged from 17 to 38 μg/L with a median of 23 μg/L, whereas perchlorate concentrations in samples from the 500-foot-deep production well (Well 2) ranged from 2.1 to 17 μg/L, with a median of 6

Fractionation of stable isotopes in perchlorate and nitrate during in situ biodegradation in a sandy aquifer

USGS Publications Warehouse

Hatzinger, P.B.; Bohlke, John Karl; Sturchio, N.C.; Gu, B.; Heraty, L.J.; Borden, R.C.

2009-01-01

An in situ experiment was performed in a shallow alluvial aquifer in Maryland to quantify the fractionation of stable isotopes in perchlorate (Cl and O) and nitrate (N and O) during biodegradation. An emulsified soybean oil substrate that was previously injected into this aquifer provided the electron donor necessary for biological perchlorate reduction and denitrification. During the field experiment, groundwater extracted from an upgradient well was pumped into an injection well located within the in situ oil barrier, and then groundwater samples were withdrawn for the next 30 h. After correction for dilution (using Br– as a conservative tracer of the injectate), perchlorate concentrations decreased by 78% and nitrate concentrations decreased by 82% during the initial 8.6 h after the injection. The observed ratio of fractionation effects of O and Cl isotopes in perchlorate (e18O/e37Cl) was 2.6, which is similar to that observed in the laboratory using pure cultures (2.5). Denitrification by indigenous bacteria fractionated O and N isotopes in nitrate at a ratio of ~0.8 (e18O/e15N), which is within the range of values reported previously for denitrification. However, the magnitudes of the individual apparent in situ isotope fractionation effects for perchlorate and nitrate were appreciably smaller than those reported in homogeneous closed systems (0.2 to 0.6 times), even after adjustment for dilution. These results indicate that (1) isotope fractionation factor ratios (e18O/e37Cl, e18O/e15N) derived from homogeneous laboratory systems (e.g. pure culture studies) can be used qualitatively to confirm the occurrence of in situ biodegradation of both perchlorate and nitrate, but (2) the magnitudes of the individual apparent e values cannot be used quantitatively to estimate the in situ extent of biodegradation of either anion.

Fractionation of stable isotopes in perchlorate and nitrate during in situ biodegradation in a sandy aquifer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatzinger, Paul B.; Bohlke, J. K.; Sturchio, N. C.

An in situ experiment was performed in a shallow alluvial aquifer in Maryland to quantify the fractionation of stable isotopes in perchlorate (Cl and O) and nitrate (N and O) during biodegradation. An emulsified soybean oil substrate that was previously injected into this aquifer provided the electron donor necessary for biological perchlorate reduction and denitrification. During the field experiment, groundwater extracted from an upgradient well was pumped into an injection well located within the in situ oil barrier, and then groundwater samples were withdrawn for the next 30 h. After correction for dilution (using Br-as a conservative tracer of themore » injectate), perchlorate concentrations decreased by 78 % and nitrate concentrations decreased by 87 %, during the initial 8.6 h after the injection. The observed ratio of fractionation effects of O and Cl isotopes in perchlorate (ε18O/ε37Cl) was 2.6, which is similar to that observed in the laboratory using pure cultures (2.5). Denitrification by indigenous bacteria fractionated O and N isotopes in nitrate at a ratio of approximately 0.8 (ε18O/ε15N), which is within the range of values reported previously for denitrification. However, the magnitudes of the individual apparent in situ isotope fractionation effects for perchlorate and nitrate were appreciably smaller than those reported in homogeneous closed systems (0.2 to 0.6 times), even after adjustment for dilution. These results indicate that (1) isotope fractionation factor ratios (ε18O/ε37Cl, ε18O/ε15N) derived from homogeneous laboratory systems (e.g., pure culture studies) can be used qualitatively to confirm the occurrence of in situ biodegradation of both perchlorate and nitrate, but (2) the magnitudes of the individual apparent  values cannot be used quantitatively to estimate the in situ extent of biodegradation of either anion.« less

Kinetics of nitrate and perchlorate reduction in ion exchange brine using the membrane biofilm reactor (MBfR)

EPA Science Inventory

Several sources of bacterial inocula were tested for their ability to reduce nitrate and perchlorate in synthetic ion-exchange spent brine (3-4.5% salinity) using a hydrogen-based membrane biofilm reactor (MBfR). Nitrate and perchlorate removal fluxes reached as high as 5.4 g N ...

CO-occurring exposure to perchlorate, nitrate and thiocyanate alters thyroid function in healthy pregnant women.

PubMed

Horton, Megan K; Blount, Benjamin C; Valentin-Blasini, Liza; Wapner, Ronald; Whyatt, Robin; Gennings, Chris; Factor-Litvak, Pam

2015-11-01

Adequate maternal thyroid function during pregnancy is necessary for normal fetal brain development, making pregnancy a critical window of vulnerability to thyroid disrupting insults. Sodium/iodide symporter (NIS) inhibitors, namely perchlorate, nitrate, and thiocyanate, have been shown individually to competitively inhibit uptake of iodine by the thyroid. Several epidemiologic studies examined the association between these individual exposures and thyroid function. Few studies have examined the effect of this chemical mixture on thyroid function during pregnancy We examined the cross sectional association between urinary perchlorate, thiocyanate and nitrate concentrations and thyroid function among healthy pregnant women living in New York City using weighted quantile sum (WQS) regression. We measured thyroid stimulating hormone (TSH) and free thyroxine (FreeT4) in blood samples; perchlorate, thiocyanate, nitrate and iodide in urine samples collected from 284 pregnant women at 12 (±2.8) weeks gestation. We examined associations between urinary analyte concentrations and TSH or FreeT4 using linear regression or WQS adjusting for gestational age, urinary iodide and creatinine. Individual analyte concentrations in urine were significantly correlated (Spearman's r 0.4-0.5, p<0.001). Linear regression analyses did not suggest associations between individual concentrations and thyroid function. The WQS revealed a significant positive association between the weighted sum of urinary concentrations of the three analytes and increased TSH. Perchlorate had the largest weight in the index, indicating the largest contribution to the WQS. Co-exposure to perchlorate, nitrate and thiocyanate may alter maternal thyroid function, specifically TSH, during pregnancy. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Co-occurring exposure to perchlorate, nitrate and thiocyanate alters thyroid function in healthy pregnant women

PubMed Central

Horton, Megan K.; Blount, Benjamin C.; Valentin-Blasini, Liza; Wapner, Ronald; Whyatt, Robin; Gennings, Chris; Factor-Litvak, Pam

2015-01-01

Background Adequate maternal thyroid function during pregnancy is necessary for normal fetal brain development, making pregnancy a critical window of vulnerability to thyroid disrupting insults. Sodium/iodide symporter (NIS) inhibitors, namely perchlorate, nitrate, and thiocyanate, have been shown individually to competitively inhibit uptake of iodine by the thyroid. Several epidemiologic studies examined the association between these individual exposures and thyroid function. Few studies have examined the effect of this chemical mixture on thyroid function during pregnancy. Objectives We examined the cross sectional association between urinary perchlorate, thiocyanate and nitrate concentrations and thyroid function among healthy pregnant women living in New York City using weighted quantile sum (WQS) regression. Methods We measured thyroid stimulating hormone (TSH) and free thyroxine (FreeT4) in blood samples; perchlorate, thiocyanate, nitrate and iodide in urine samples collected from 284 pregnant women at 12 (± 2.8) weeks gestation. We examined associations between urinary analyte concentrations and TSH or FreeT4 using linear regression or WQS adjusting for gestational age, urinary iodide and creatinine. Results Individual analyte concentrations in urine were significantly correlated (Spearman’s r 0.4–0.5, p < 0.001). Linear regression analyses did not suggest associations between individual concentrations and thyroid function. The WQS revealed a significant positive association between the weighted sum of urinary concentrations of the three analytes and increased TSH. Perchlorate had the largest weight in the index, indicating the largest contribution to the WQS. Conclusions Co-exposure to perchlorate, nitrate and thiocyanate may alter maternal thyroid function, specifically TSH, during pregnancy. PMID:26408806

Bioelectroremediation of perchlorate and nitrate contaminated water: A review.

PubMed

Sevda, Surajbhan; Sreekishnan, T R; Pous, Narcís; Puig, Sebastià; Pant, Deepak

2018-05-01

Fresh water is a fundamental source for humans, hence the recent shrinkage in freshwater and increase in water pollution are imperative problems that vigorously affect the people and the environment worldwide. The breakneck industrialization contributes to the procreation of substantial abundance of wastewater and its treatment becomes highly indispensable. Perchlorate and nitrate containing wastewaters poses a serious threat to human health and environment. Conventional biological treatment methods are expensive and also not effective for treating wastewater effectively and incapable of in situ bioremediation. Bioelectrochemical systems are emerging as a new technology platform for a sustainable removal of such contaminants from wastewater streams. This article reviews the state of art of bioelectroremediation of contaminated waters with perchlorate and nitrate. Different aspects of this technology such as configuration and design, mode of operation and type of substrate are considered in detail. Copyright © 2018 Elsevier Ltd. All rights reserved.

Studies on the synthesis, characterization, human serum albumin binding and biological activity of single chain surfactant-cobalt(III) complexes.

PubMed

Vignesh, G; Sugumar, K; Arunachalam, S; Vignesh, S; Arthur James, R; Arun, R; Premkumar, K

2016-03-01

The interaction of surfactant-cobalt(III) complexes [Co(bpy)(dien)TA](ClO4)3 · 3H2O (1) and [Co(dien)(phen)TA](ClO4)3 · 4H2O (2), where bpy = 2,2'-bipyridine, dien = diethylenetriamine, phen = 1,10-phenanthroline and TA = tetradecylamine with human serum albumin (HSA) under physiological conditions was analyzed using steady state, synchronous, 3D fluorescence, UV/visabsorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of HSA through a static mechanism. The binding constant (Kb ) and number of binding-sites (n) were obtained at different temperatures. The corresponding thermodynamic parameters (∆G°, ∆H° and ∆S°) and Ea were also obtained. According to Förster's non-radiation energy transfer theory, the binding distance (r) between the complexes and HSA were calculated. The results of synchronous and 3D fluorescence spectroscopy indicate that the binding process has changed considerably the polarity around the fluorophores, along with changes in the conformation of the protein. The antimicrobial and anticancer activities of the complexes were tested and the results show that the complexes have good activities against pathogenic microorganisms and cancer cells. Copyright © 2015 John Wiley & Sons, Ltd.

Detection of boron, cobalt, and other weak interstellar lines toward Zeta Ophiuchi

NASA Technical Reports Server (NTRS)

Federman, S. R.; Sheffer, Y.; Lambert, D. L.; Gilliland, R. L.

1993-01-01

Numerous weak lines from interstellar atomic species toward Zeta Ophiuchi were observed with the Goddard High-Resolution Spectrograph. Of particular note are the first interstellar detection of cobalt and the detection of boron in this sight line. These measurements provide estimates for the amount of depletion for the two elements. Boron, a volatile, and cobalt, a refractory element, display the depletion pattern found by Savage et al. (1992). The abundance of phosphorus in the H II region associated with the star was obtained from a detection of P III. Additional weak lines from S I, C I, Ni II, and Cu II were detected for the first time; these lines provide the basis for refinements in oscillator strength and column density. Analysis of the neutral sulfur data indicates that the atomic gas is more widely distributed than the molecular material in the main component.

DETERMINATION OF PERCHLORATE AT TRACE LEVELS IN DRINKING WATER BY ION-PAIR EXTRACTION WITH ELECTROSPRAY IONIZATION MASS SPECTROMETRY.

EPA Science Inventory

Perchlorate has been added to the U.S. Environmental Protection Agency,s Drinking Water Contaminant Candidate List (CCL). The present work describes the analysis of perchlorate in water by liquid-liquid extraction followed by flow injection electrospray mass spectrometry (ESI/MS...

Highly selective optical fluoride ion sensor with submicromolar detection limit based on aluminum(III) octaethylporphyrin in thin polymeric film.

PubMed

Badr, Ibrahim H A; Meyerhoff, Mark E

2005-04-20

A highly selective, sensitive, and reversible fluoride optical sensing film based on aluminum(III)octaethylporphyrin as a fluoride ionophore and a lipophilic pH indicator as the optical transducer is described. The fluoride optical sensing films exhibit a submicromolar detection limit and high discrimination for fluoride over several lipophilic anions such as nitrate, perchlorate, and thiocyanate.

Possible Calcite and Magnesium Perchlorate Interaction in the Mars Phoenix Thermal and Evolved Gas Analyzer (TEGA)

NASA Technical Reports Server (NTRS)

Cannon, K. M.; Sutter, B.; Ming, D. W.; Boynton, W. V.; Quinn, R. C.

2012-01-01

The Mars Phoenix Lander's TEGA instrument detected a calcium carbonate phase decomposing at high temperatures (approx.700 C) from the Wicked Witch soil sample [1]. TEGA also detected a lower temperature CO2 release between 400 C and 680 C [1]. Possible explanations given for this lower temperature CO2 release include thermal decomposition of Mg or Fe carbonates, a zeolitictype desorption reaction, or combustion of organic compounds in the soil [2]. The detection of 0.6 wt % soluble perchlorate by the Wet Chemistry Laboratory (WCL) on Phoenix [3] has implications for the possibility of organic molecules in the soil. Ming et al. [4] demonstrated that perchlorates could have oxidized organic compounds to CO2 in TEGA, preventing detection of their characteristic mass fragments. Here, we propose that a perchlorate salt and calcium carbonate present in martian soil reacted to produce the 400 C - 680 C TEGA CO2 release. The parent salts of the perchlorate on Mars are unknown, but geochemical models using WCL data support the possible dominance of Mg-perchlorate salts [5]. Mg(ClO4)2 6H2O is the stable phase at ambient martian conditions [6], and breaks down at lower temperatures than carbonates giving off Cl2 and HCl gas [7,8]. Devlin and Herley [7] report two exotherms at 410-478 C and 473-533 C which correspond to the decomposition of Mg(ClO4)2.

Determination of trace level bromate and perchlorate in drinking water by ion chromatography with an evaporative preconcentration technique.

PubMed

Liu, Yongjian; Mou, Shifen; Heberling, Shawn

2002-05-17

A simple sample preconcentration technique employing microwave-based evaporation for the determination of trace level bromate and perchlorate in drinking water with ion chromatography is presented. With a hydrophilic anion-exchange column and a sodium hydroxide eluent in linear gradient, bromate and perchlorate can be determined in one injection within 35 min. Prior to ion chromatographic analysis, the drinking water sample was treated with an OnGuard-Ag cartridge to remove the superfluous chloride and concentrated 20-fold using a PTFE beaker in a domestic microwave oven for 15 min. The recoveries of the anions ranged from 94.6% for NO2- to 105.2% for F-. The detection limits for bromate, perchlorate, iodate and chlorate were 0.1, 0.2, 0.1 and 0.2 microg/l, respectively. The developed method is applicable for the quantitation of bromate and perchlorate in drinking water samples.

Nitrogen-doped carbon-supported cobalt-iron oxygen reduction catalyst

DOEpatents

Zelenay, Piotr; Wu, Gang

2014-04-29

A Fe--Co hybrid catalyst for oxygen reaction reduction was prepared by a two part process. The first part involves reacting an ethyleneamine with a cobalt-containing precursor to form a cobalt-containing complex, combining the cobalt-containing complex with an electroconductive carbon supporting material, heating the cobalt-containing complex and carbon supporting material under conditions suitable to convert the cobalt-containing complex and carbon supporting material into a cobalt-containing catalyst support. The second part of the process involves polymerizing an aniline in the presence of said cobalt-containing catalyst support and an iron-containing compound under conditions suitable to form a supported, cobalt-containing, iron-bound polyaniline species, and subjecting said supported, cobalt-containing, iron bound polyaniline species to conditions suitable for producing a Fe--Co hybrid catalyst.

Direct Fixed-Bed Biological Perchlorate Destruction Demonstration

DTIC Science & Technology

2008-09-01

1 mg/L)? This issue targets the question of whether the FXB bioreactor system can be applied at a remediation site (i.e., a non-potable...incineration). 11 3. PERFORMANCE OBJECTIVES 3.1 Summary Performance objectives listed in Table 3.1 apply to the complete FXB bioreactor...potential sources of perchlorate. Other areas near Well #2 have been used by a multitude of companies for ordnance and pyrotechnics manufacturing

Theoretical analysis of the influence of chelate-ring size and vicinal effects on electronic circular dichroism spectra of cobalt(III) EDDA-type complexes.

PubMed

Wang, Ai; Wang, Yuekui; Jia, Jie; Feng, Lixia; Zhang, Chunxia; Liu, Linlin

2013-06-20

To assess the contributions of configurational and vicinal effects as well as chelate-ring size to rotational strengths, the geometries of a series of cobalt(III) complexes [Co(EDDA-type)(L)](±) with the tetradentate EDDA-type ligands, EDDA (ethylenediamine-N,N'-diacetate), DMEDDA (N,N'-dimethylethylenediamine-N,N'-diacetate), DEEDDA (N,N'-diethylethylenediamine-N,N'-diacetate), and a bidentate ancillary ligand L (L = ethylenediamine, oxalate, carbonate, (S)-alanine, and malonate) in aqueous solution have been optimized at the DFT/B3LYP/6-311++G(2d,p) level of theory. Based on the optimized geometries, the excitation energies and oscillator and rotational strengths have been calculated using the time-dependent density functional theory (TDDFT) method with the same functional and basis set. The calculated circular dichroism (CD) curves are in excellent agreement with the observed ones except for some small red or blue shifts in peak wavelengths. For the influence of chelate-ring size of the bidentate ligands on the CD intensities, a qualitative analysis together with the quantitative TDDFT calculation reveal that it depends on the symmetry of the cobalt-EDDA backbone. For the s-cis-isomers, the influence is negligible due to the perturbation is symmetric. For the uns-cis-isomers, the perturbation is unsymmetric. Since a small ring size means a large perturbation, this leads to the integral CD intensities decreasing with increasing the chelate ring size. The vicinal effects of asymmetric nitrogens incorporate both the substitutent effects and conformational relaxation effects, with the former being dominant. By analyzing the contributions of chiral arrays to rotational strengths, we found that the part of contributions dominated by the S-type chiral nitrogens could be considered as a good measure for the vicinal effects of chiral nitrogens. In addition, we found that the twist form (δ/λ) of the backbone ethylenediamine ring (E-ring) of the coordinated EDDA

Optical ordnance system for use in explosive ordnance disposal activities

NASA Technical Reports Server (NTRS)

Merson, J. A.; Salas, F. J.; Helsel, F.M.

1994-01-01

A portable hand-held solid state rod laser system and an optically-ignited detonator have been developed for use in explosive ordnance disposal (EOD) activities. Laser prototypes from Whittaker Ordnance and Universal Propulsion have been tested and evaluated. The optical detonator contains 2-(5 cyanotetrazolato) pentaamine cobalt(III) perchlorate (CP) as the DDT column and the explosive Octahydro- 1,3,5,7 - tetrazocine (HMX) as the output charge. The laser is designed to have an output of 150 mJ in a 500 microsecond pulse. This output allows firing through 2000 meters of optical fiber. The detonator can also be ignited with a portable laser diode source through a shorter length of fiber.

POLISHING THE EFFLUENT FROM AN ANAEROBIC BIOLOGICAL PERCHLORATE TREATMENT PROCESS

EPA Science Inventory

Anaerobic biological processes effectively reduce perchlorate to chloride. However, the effluent can be biologically unstable, high in particulates and high in disinfection by-product precursor compounds. Such an effluent would be unsuitable for transmission into a drinking water...

Influence of nitrate, sulfate and operational parameters on the bioreduction of perchlorate using an up-flow packed bed reactor at high salinity.

PubMed

Chung, J; Shin, S; Oh, J

2010-05-01

In this study we have investigated whether electron acceptors, such as nitrate or sulphate ions, competitively inhibit the reduction of perchlorate in brine in continuous up-flow packed bed bioreactors. The effect of pH and hydraulic retention time (HRT) on the reduction of perchlorate at high salinity has also been examined. Reduction of perchlorate was found to be only moderately influenced by nitrate (under 163 mg N L-'), implying that there was no significant microbial competition for electron acceptors. As a result of microbial diversity, there were few differences between microbial communities fed with a variety of media, suggesting that most nitrate-reducing bacteria are able to reduce perchlorate at high salinity. Reduction of perchlorate was almost complete at relatively high sulfate levels (1000 mg L(-1)), neutral pH (6-8) and relatively long HRTs (> 10 h).

Combined Hydrous Ferric Oxide and Quaternary Ammonium Surfactant Tailoring of Granular Activated Carbon for Concurrent Arsenate and Perchlorate Removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, M.; Cannon, F; Parette, R

2009-01-01

Activated carbon was tailored with both iron and quaternary ammonium surfactants so as to concurrently remove both arsenate and perchlorate from groundwater. The iron (hydr)oxide preferentially removed the arsenate oxyanion but not perchlorate; while the quaternary ammonium preferentially removed the perchlorate oxyanion, but not the arsenate. The co-sorption of two anionic oxyanions via distinct mechanisms has yielded intriguing phenomena. Rapid small-scale column tests (RSSCTs) with these dually prepared media employed synthetic waters that were concurrently spiked with arsenate and perchlorate; and these trial results showed that the quaternary ammonium surfactants enhanced arsenate removal bed life by 25-50% when compared tomore » activated carbon media that had been preloaded merely with iron (hydr)oxide; and the surfactant also enhanced the diffusion rate of arsenate per the Donnan effect. The authors also employed natural groundwater from Rutland, MA which contained 60 microg/L As and traces of silica, and sulfate; and the authors spiked this with 40 microg/L perchlorate. When processing this water, activated carbon that had been tailored with iron and cationic surfactant could treat 12,500 bed volumes before 10 microg/L arsenic breakthrough, and 4500 bed volumes before 6 microg/L perchlorate breakthrough. Although the quaternary ammonium surfactants exhibited only a slight capacity for removing arsenate, these surfactants did facilitate a more favorably positively charged avenue for the arsenate to diffuse through the media to the iron sorption site (i.e. via the Donnan effect).« less

Association between Perchlorate and indirect indicators of thyroid dysfunction in NHANES 2001-2002, a Cross-Sectional, Hypothesis-Generating Study

EPA Science Inventory

Background: A previous study observed associations of urinary perchlorate with thyroid hormones based on the National Health and Nutrition Examination Survey (NHANES) 2001-2002. Increased levels of urinary perchlorate were associated with increased levels of thyroid stimulating h...

76 FR 7762 - Drinking Water: Regulatory Determination on Perchlorate

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-11

... NOEL--no observed effect level NPDWR--National Primary Drinking Water Regulation NRC--National Research... Research Council (NRC) published ``Health Implications of Perchlorate Ingestion,'' a review of the state of... the threshold. For example, if a PWS with 10 entry points serving 200,000 people had a sample from a...

Combined Effects of Perchlorate, Thiocyanate, and Iodine on Thyroid Function in the National Health and Nutrition Examination Survey 2007-8

PubMed Central

Steinmaus, Craig; Miller, Mark D.; Cushing, Lara; Blount, Benjamin C.; Smith, Allan H.

2013-01-01

Perchlorate, thiocyanate, and low iodine intake can all decrease iodide intake into the thyroid gland. This can reduce thyroid hormone production since iodide is a key component of thyroid hormone. Previous research has suggested that each of these factors alone may decrease thyroid hormone levels, but effect sizes are small. We hypothesized that people who have all three factors at the same time have substantially lower thyroid hormone levels than people who do not, and the effect of this combined exposure is substantially larger than the effects seen in analyses focused on only one factor at a time. Using data from the 2007-2008 National Health and Nutrition Examination Survey, subjects were categorized into exposure groups based on their urinary perchlorate, iodine, and thiocyanate concentrations, and mean serum thyroxine concentrations were compared between groups. Subjects with high perchlorate (n=1939) had thyroxine concentrations that were 5.0% lower (mean difference = 0.40 µg/dl, 95% confidence interval=0.14-0.65) than subjects with low perchlorate (n=2084). The individual effects of iodine and thiocyanate were even smaller. Subjects with high perchlorate, high thiocyanate, and low iodine combined (n=62) had thyroxine concentrations 12.9% lower (mean difference = 1.07 µg/dl, 95% confidence interval=0.55-1.59) than subjects with low perchlorate, low thiocyanate, and adequate iodine (n=376). Potential confounders had little impact on results. Overall, these results suggest that concomitant exposure to perchlorate, thiocyanate, and low iodine markedly reduces thyroxine production. This highlights the potential importance of examining the combined effects of multiple agents when evaluating the toxicity of thyroid-disrupting agents. PMID:23473920

37Cl/35Cl isotope ratio analysis in perchlorate by ion chromatography/multi collector -ICPMS: Analytical performance and implication for biodegradation studies.

PubMed

Zakon, Yevgeni; Ronen, Zeev; Halicz, Ludwik; Gelman, Faina

2017-10-01

In the present study we propose a new analytical method for 37 Cl/ 35 Cl analysis in perchlorate by Ion Chromatography(IC) coupled to Multicollector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS). The accuracy of the analytical method was validated by analysis of international perchlorate standard materials USGS-37 and USGS -38; analytical precision better than ±0.4‰ was achieved. 37 Cl/ 35 Cl isotope ratio analysis in perchlorate during laboratory biodegradation experiment with microbial cultures enriched from the contaminated soil in Israel resulted in isotope enrichment factor ε 37 Cl = -13.3 ± 1‰, which falls in the range reported previously for perchlorate biodegradation by pure microbial cultures. The proposed analytical method may significantly simplify the procedure for isotope analysis of perchlorate which is currently applied in environmental studies. Copyright © 2017. Published by Elsevier Ltd.

Mineral resource of the month: cobalt

USGS Publications Warehouse

Shedd, Kim B.

2009-01-01

Cobalt is a metal used in numerous commercial, industrial and military applications. On a global basis, the leading use of cobalt is in rechargeable lithium-ion, nickel-cadmium and nickel-metal hydride battery electrodes. Cobalt use has grown rapidly since the early 1990s, with the development of new battery technologies and an increase in demand for portable electronics such as cell phones, laptop computers and cordless power tools.

The Investigation of Perchlorate/Iron Phase Mixtures as A Possible Source of Oxygen Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Sutter, B.; Heil, E.; Morris, R. V.; Archer, P. D.; Ming, D. W.; Niles, P. B.; Eigenbrode, J. L.; Franz, H.; Freissinet C.; Glavin, D. P.;

The Role of External Inputs and Internal Cycling in Shaping the Global Ocean Cobalt Distribution: Insights From the First Cobalt Biogeochemical Model

NASA Astrophysics Data System (ADS)

Tagliabue, Alessandro; Hawco, Nicholas J.; Bundy, Randelle M.; Landing, William M.; Milne, Angela; Morton, Peter L.; Saito, Mak A.

2018-04-01

Cobalt is an important micronutrient for ocean microbes as it is present in vitamin B12 and is a co-factor in various metalloenzymes that catalyze cellular processes. Moreover, when seawater availability of cobalt is compared to biological demands, cobalt emerges as being depleted in seawater, pointing to a potentially important limiting role. To properly account for the potential biological role for cobalt, there is therefore a need to understand the processes driving the biogeochemical cycling of cobalt and, in particular, the balance between external inputs and internal cycling. To do so, we developed the first cobalt model within a state-of-the-art three-dimensional global ocean biogeochemical model. Overall, our model does a good job in reproducing measurements with a correlation coefficient of >0.7 in the surface and >0.5 at depth. We find that continental margins are the dominant source of cobalt, with a crucial role played by supply under low bottom-water oxygen conditions. The basin-scale distribution of cobalt supplied from margins is facilitated by the activity of manganese-oxidizing bacteria being suppressed under low oxygen and low temperatures, which extends the residence time of cobalt. Overall, we find a residence time of 7 and 250 years in the upper 250 m and global ocean, respectively. Importantly, we find that the dominant internal resupply process switches from regeneration and recycling of particulate cobalt to dissolution of scavenged cobalt between the upper ocean and the ocean interior. Our model highlights key regions of the ocean where biological activity may be most sensitive to cobalt availability.

PREDICTING FIELD PERFORMANCE OF HERBACEOUS SPECIES FOR PHYTOREMEDIATION OF PERCHLORATE

EPA Science Inventory

Results of these short-term experiments coupled with ecological knowledge of the nine herbaceous plant species tested suggest that several species may by successful in on-site remediation of perchlorate. The two wetland species which appear to be most suitable for field experimen...

Cyanide Scavenging by a Cobalt Schiff-Base Macrocycle: A Cost-Effective Alternative to Corrinoids.

PubMed

Lopez-Manzano, Elisenda; Cronican, Andrea A; Frawley, Kristin L; Peterson, Jim; Pearce, Linda L

2016-06-20

The complex of cobalt(II) with the ligand 2,12-dimethyl-3,7,11,17-tetraazabicyclo-[11.3.1]heptadeca-1(17)2,11,13,15-pentaene (CoN4[11.3.1]) has been shown to bind two molecules of cyanide in a cooperative fashion with an association constant of 2.7 (±0.2) × 10(5). In vivo, irrespective of whether it is initially administered as the Co(II) or Co(III) cation, EPR spectroscopic measurements on blood samples show that at physiological levels of reductant (principally ascorbate) CoN4[11.3.1] becomes quantitatively reduced to the Co(II) form. However, following addition of sodium cyanide, a dicyano Co(III) species is formed, both in blood and in buffered aqueous solution at neutral pH. In keeping with other cobalt-containing cyanide-scavenging macrocycles like cobinamide and cobalt(III) meso-tetra(4-N-methylpyridyl)porphine, we found that CoN4[11.3.1] exhibits rapid oxygen turnover in the presence of the physiological reductant ascorbate. This behavior could potentially render CoN4[11.3.1] cytotoxic and/or interfere with evaluations of the antidotal capability of the complex toward cyanide through respirometric measurements, particularly since cyanide rapidly inhibits this process, adding further complexity. A sublethal mouse model was used to assess the effectiveness of CoN4[11.3.1] as a potential cyanide antidote. The administration of CoN4[11.3.1] prophylactically to sodium cyanide-intoxicated mice resulted in the time required for the surviving animals to recover from "knockdown" (unconsciousness) being significantly decreased (3 ± 2 min) compared to that of the controls (22 ± 5 min). All observations are consistent with the demonstrated antidotal activity of CoN4[11.3.1] operating through a cyanide-scavenging mechanism, which is associated with a Co(II) → Co(III) oxidation of the cation. To test for postintoxication neuromuscular sequelae, the ability of mice to remain in position on a rotating cylinder (RotaRod test) was assessed during and after recovery

Palladium-cobalt particles as oxygen-reduction electrocatalysts

DOEpatents

Adzic, Radoslav [East Setauket, NY; Huang, Tao [Manorville, NY

2009-12-15

The present invention relates to palladium-cobalt particles useful as oxygen-reducing electrocatalysts. The invention also relates to oxygen-reducing cathodes and fuel cells containing these palladium-cobalt particles. The invention additionally relates to methods for the production of electrical energy by using the palladium-cobalt particles of the invention.

Synthesis, crystal structure, catecholase and phenoxazinone synthase activities of a mononuclear cobalt(III) complex containing in situ formed tridentate N-donor Schiff base

NASA Astrophysics Data System (ADS)

Maji, Ashis Kumar; Chatterjee, Arnab; Khan, Sumitava; Ghosh, Barindra Kumar; Ghosh, Rajarshi

2017-10-01

Synthesis and structural characterization of a mononuclear cobalt(III) Schiff base complex is reported. It crystallizes with monoclinic crystal system with P21/n space group with a = 9.9793(4) Å, b = 28.2907(12) Å and c = 13.1233(6) Å, and β = 97.532(3)°. The compound is active to catecholase and phenoxazinone synthase activities in MeOH, and MeOH and MeCN solvents, respectively at room temperature. Each of the reactions was found to be of first order with reaction rate 8.08 × 10-3 min-1 (MeOH) for the catecholase activity and 1.05 × 10-3 min-1 (MeOH) and 3.82 × 10-3 min-1 (MeCN) for the phenoxazinone synthase activity. The turn over numbers for the catecholase activity is 5.02 × 103 h-1 (MeOH) and for the phenoxazinone synthase activity is 4.59 × 103 h-1 (MeOH) and 5.12 × 103 h-1 (MeCN). Substrate-catalyst adduct was tried to be trapped in each case using mass spectrometry.

NOVEL ASSOCIATIONS BETWEEN URINARY PERCHLORATE AND POTENTIALLY RELEVANT EFFECTS ON RISK FACTORS FOR HEART DISEASE BASED ON NHANES 2001-2002

EPA Science Inventory

Perchlorate is a widespread environmental pollutant, and is a thyroid hormone disruptor. A previous population study based on the National Health and Nutrition Examination Survey (NHANES) 2001-2002 database showed that urinary perchlorate concentrations were associated with signi...

Microbial Community Structure during Nitrate and Perchlorate Reduction in Ion-exchange Brine Using the Hydrogen-based membrane Biofilm Reactor (MBIR)

EPA Science Inventory

Detoxification of perchlorate by microbial communities under denitrifying conditions has been recently reported, although the identity of the mixed populations involved in perchlorate reduction is not well understood. In order to address this, the bacterial diversity of membrane ...

Cobalt: for strength and color

USGS Publications Warehouse

Boland, Maeve A.; Kropschot, S.J.

2011-01-01

Cobalt is a shiny, gray, brittle metal that is best known for creating an intense blue color in glass and paints. It is frequently used in the manufacture of rechargeable batteries and to create alloys that maintain their strength at high temperatures. It is also one of the essential trace elements (or "micronutrients") that humans and many other living creatures require for good health. Cobalt is an important component in many aerospace, defense, and medical applications and is a key element in many clean energy technologies. The name cobalt comes from the German word kobold, meaning goblin. It was given this name by medieval miners who believed that troublesome goblins replaced the valuable metals in their ore with a substance that emitted poisonous fumes when smelted. The Swedish chemist Georg Brandt isolated metallic cobalt-the first new metal to be discovered since ancient times-in about 1735 and identified some of its valuable properties.

Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars

NASA Astrophysics Data System (ADS)

Navarro-González, Rafael; Vargas, Edgar; de la Rosa, José; Raga, Alejandro C.; McKay, Christopher P.

2010-12-01

The most comprehensive search for organics in the Martian soil was performed by the Viking Landers. Martian soil was subjected to a thermal volatilization process to vaporize and break organic molecules, and the resultant gases and volatiles were analyzed by gas chromatography-mass spectrometry. Only water at 0.1-1.0 wt% was detected, with traces of chloromethane at 15 ppb, at Viking landing site 1, and water at 0.05-1.0 wt% and carbon dioxide at 50-700 ppm, with traces of dichloromethane at 0.04-40 ppb, at Viking landing site 2. These chlorohydrocarbons were considered to be terrestrial contaminants, although they had not been detected at those levels in the blank runs. Recently, perchlorate was discovered in the Martian Arctic soil by the Phoenix Lander. Here we show that when Mars-like soils from the Atacama Desert containing 32 ± 6 ppm of organic carbon are mixed with 1 wt% magnesium perchlorate and heated, nearly all the organics present are decomposed to water and carbon dioxide, but a small amount is chlorinated, forming 1.6 ppm of chloromethane and 0.02 ppm of dichloromethane at 500°C. A chemical kinetics model was developed to predict the degree of oxidation and chlorination of organics in the Viking oven. Reinterpretation of the Viking results therefore suggests ≤0.1% perchlorate and 1.5-6.5 ppm organic carbon at landing site 1 and ≤0.1% perchlorate and 0.7-2.6 ppm organic carbon at landing site 2. The detection of organics on Mars is important to assess locations for future experiments to detect life itself.

RAMAN SPECTROSCOPIC ANALYSIS OF FERTILIZERS AND PLANT TISSUE FOR PERCHLORATE

EPA Science Inventory

Raman spectroscopy, without the need for prior chromatographic separation, was used for qualitative and quantitative analysis of 59 samples of fertilizers for perchlorate (ClO4-). These primarily lawn and garden products had no known link to Chile saltpeter, which is known to con...

Cobalt recycling in the United States in 1998

USGS Publications Warehouse

Shedd, Kim B.

2002-01-01

This report is one of a series of reports on metals recycling. It defines and quantifies the 1998 flow of cobalt-bearing materials in the United States, from imports and stock releases through consumption and disposition, with particular emphasis on the recycling of industrial scrap (new scrap) and used products (old scrap). Because of cobalt?s many and diverse uses, numerous types of scrap were available for recycling by a wide variety of processes. In 1998, an estimated 32 percent of U.S. cobalt supply was derived from scrap. The ratio of cobalt consumed from new scrap to that from old scrap was estimated to be 50:50. Of all the cobalt in old scrap available for recycling, an estimated 68 percent was either consumed in the United States or exported to be recycled.

The Effect of Mars-relevant Minerals on the Water Uptake of Magnesium Perchlorate and Implications for the Near-surface of Mars

NASA Astrophysics Data System (ADS)

Primm, Katherine; Gough, Raina; Rivera-Valentin, Edgard G.; Tolbert, Margaret

2017-10-01

The water uptake and release by hygroscopic salts such as perchlorate has been well studied in the decade since they were first discovered on the surface of Mars. However, there have been few studies on the effect of the insoluble regolith minerals on this well documented interaction of perchlorate and water vapor. In this work, we investigate the effect that two insoluble Mars-relevant minerals, montmorillonite and Mojave Mars Simulant (MMS), have on the water uptake (deliquescence), ice formation, and recrystallization (efflorescence) of pure magnesium perchlorate. We studied mixtures of equal parts (by mass) magnesium perchlorate hexahydrate and either montmorillonite or MMS. Although montmorillonite and MMS are insoluble minerals that may serve as nuclei for either ice nucleation or salt efflorescence, we find that these minerals did not affect any of the phase transitions of magnesium perchlorate. The salt-mineral mixture behaved like pure magnesium perchlorate in all cases, with stable deliquescence as well as metastable brine supersaturation and supercooling observed. Experiments were performed in both N2 and CO2 atmospheres, with no detectable difference. We use data from the Rover Environmental Monitoring Station instrument on MSL and from the Thermal and Electrical Conductivity Probe instrument on Phoenix, as well as modeling of the shallow subsurface near the rover and lander, to determine the likelihood of liquid water and water ice at Gale Crater and the Phoenix landing site.

Electrochemical synthesis of azanucleoside derivatives using a lithium perchlorate-nitromethane system.

PubMed

Kim, Shokaku; Shoji, Takao; Kitano, Yoshikazu; Chiba, Kazuhiro

2013-07-25

We have developed a highly efficient synthetic method for azanucleosides using a lithium perchlorate-nitromethane reaction medium, allowing direct and exclusive installation of various nucleophiles, including protected nucleobases into prolinol derivatives at the preferred 5-position.

Effects of cobalt in nickel-base superalloys

NASA Technical Reports Server (NTRS)

Tien, J. K.; Jarrett, R. N.

1983-01-01

The role of cobalt in a representative wrought nickel-base superalloy was determined. The results show cobalt affecting the solubility of elements in the gamma matrix, resulting in enhanced gamma' volume fraction, in the stabilization of MC-type carbides, and in the stabilization of sigma phase. In the particular alloy studied, these microstructural and microchemistry changes are insufficient in extent to impact on tensile strength, yield strength, and in the ductilities. Depending on the heat treatment, creep and stress rupture resistance can be cobalt sensitive. In the coarse grain, fully solutioned and aged condition, all of the alloy's 17% cobalt can be replaced by nickel without deleteriously affecting this resistance. In the fine grain, partially solutioned and aged condition, this resistance is deleteriously affected only when one-half or more of the initial cobalt content is removed. The structure and property results are discussed with respect to existing theories and with respect to other recent and earlier findings on the impact of cobalt, if any, on the performance of nickel-base superalloys.

Evaluation of the risk of perchlorate exposure in a population of late-gestation pregnant women in the United States: Application of probabilistic biologically-based dose response modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumen, A, E-mail: Annie.Lumen@fda.hhs.gov

The risk of ubiquitous perchlorate exposure and the dose-response on thyroid hormone levels in pregnant women in the United States (U.S.) have yet to be characterized. In the current work, we integrated a previously developed perchlorate submodel into a recently developed population-based pregnancy model to predict reductions in maternal serum free thyroxine (fT4) levels for late-gestation pregnant women in the U.S. Our findings indicated no significant difference in geometric mean estimates of fT4 when perchlorate exposure from food only was compared to no perchlorate exposure. The reduction in maternal fT4 levels reached statistical significance when an added contribution from drinkingmore » water (i.e., 15 μg/L, 20 μg/L, or 24.5 μg/L) was assumed in addition to the 90th percentile of food intake for pregnant women (0.198 μg/kg/day). We determined that a daily intake of 0.45 to 0.50 μg/kg/day of perchlorate was necessary to produce results that were significantly different than those obtained from no perchlorate exposure. Adjusting for this food intake dose, the relative source contribution of perchlorate from drinking water (or other non-dietary sources) was estimated to range from 0.25–0.3 μg/kg/day. Assuming a drinking water intake rate of 0.033 L/kg/day, the drinking water concentration allowance for perchlorate equates to 7.6–9.2 μg/L. In summary, we have demonstrated the utility of a probabilistic biologically-based dose-response model for perchlorate risk assessment in a sensitive life-stage at a population level; however, there is a need for continued monitoring in regions of the U.S. where perchlorate exposure may be higher. - Highlights: • Probabilistic risk assessment for perchlorate in U.S. pregnant women was conducted. • No significant change in maternal fT4 predicted due to perchlorate from food alone. • Drinking water concentration allowance for perchlorate estimated as 7.6–9.2 μg/L.« less

Cobalt: A vital element in the aircraft engine industry

NASA Technical Reports Server (NTRS)

Stephens, J. R.

1981-01-01

Recent trends in the United States consumption of cobalt indicate that superalloys for aircraft engine manufacture require increasing amounts of this strategic element. Superalloys consume a lion's share of total U.S. cobalt usage which was about 16 million pounds in 1980. In excess of 90 percent of the cobalt used in this country was imported, principally from the African countries of Zaire and Zambia. Early studies on the roles of cobalt as an alloying element in high temperature alloys concentrated on the simple Ni-Cr and Nimonic alloy series. The role of cobalt in current complex nickel base superalloys is not well defined and indeed, the need for the high concentration of cobalt in widely used nickel base superalloys is not firmly established. The current cobalt situation is reviewed as it applies to superalloys and the opportunities for research to reduce the consumption of cobalt in the aircraft engine industry are described.

Characteristics of polyaniline cobalt supported catalysts for epoxidation reactions.

PubMed

Kowalski, Grzegorz; Pielichowski, Jan; Grzesik, Mirosław

2014-01-01

A study of polyaniline (PANI) doping with various cobalt compounds, that is, cobalt(II) chloride, cobalt(II) acetate, and cobalt(II) salen, is presented. The catalysts were prepared by depositing cobalt compounds onto the polymer surface. PANI powders containing cobalt ions were obtained by one- or two-step method suspending PANI in the following acetonitrile/acetic acid solution or acetonitrile and then acetic acid solution. Moreover different ratios of Co(II) : PANI were studied. Catalysts obtained with both methods and at all ratios were investigated using various techniques including AAS and XPS spectroscopy. The optimum conditions for preparation of PANI/Co catalysts were established. Catalytic activity of polyaniline cobalt(II) supported catalysts was tested in dec-1-ene epoxidation with molecular oxygen at room temperature. The relationship between the amount of cobalt species, measured with both AAS and XPS techniques, and the activity of PANI-Co catalysts has been established.

Characteristics of Polyaniline Cobalt Supported Catalysts for Epoxidation Reactions

PubMed Central

Kowalski, Grzegorz; Pielichowski, Jan; Grzesik, Mirosław

2014-01-01

A study of polyaniline (PANI) doping with various cobalt compounds, that is, cobalt(II) chloride, cobalt(II) acetate, and cobalt(II) salen, is presented. The catalysts were prepared by depositing cobalt compounds onto the polymer surface. PANI powders containing cobalt ions were obtained by one- or two-step method suspending PANI in the following acetonitrile/acetic acid solution or acetonitrile and then acetic acid solution. Moreover different ratios of Co(II) : PANI were studied. Catalysts obtained with both methods and at all ratios were investigated using various techniques including AAS and XPS spectroscopy. The optimum conditions for preparation of PANI/Co catalysts were established. Catalytic activity of polyaniline cobalt(II) supported catalysts was tested in dec-1-ene epoxidation with molecular oxygen at room temperature. The relationship between the amount of cobalt species, measured with both AAS and XPS techniques, and the activity of PANI-Co catalysts has been established. PMID:24701183

Spatial distribution of perchlorate, iodide and thiocyanate in the aquatic environment of Tianjin, China: environmental source analysis.

PubMed

Qin, Xiaolei; Zhang, Tao; Gan, Zhiwei; Sun, Hongwen

2014-09-01

Although China is the largest producer of fireworks (perchlorate-containing products) in the world, the pathways through which perchlorate enters the environment have not been characterized completely in this country. In this study, perchlorate, iodide and thiocyanate were measured in 101 water samples, including waste water, surface water, sea water and paired samples of rain water and surface runoff collected in Tianjin, China. The concentrations of the target anions were generally on the order of rain>surface water≈waste water treatment plant (WWTP) influent>WWTP effluent. High concentrations of perchlorate, iodide and thiocyanate were detected in rain samples, ranging from 0.35 to 27.3 (median: 4.05), 0.51 to 8.33 (2.92), and 1.31 to 107 (5.62) ngmL(-)(1), respectively. Furthermore, the concentrations of the target anions in rain samples were significantly (r=0.596-0.750, p<0.01) positively correlated with the concentrations obtained in the paired surface runoff samples. The anions tested showed a clear spatial distribution, and higher concentrations were observed in the upper reaches of rivers, sea waters near the coast, and rain-surface runoff pairs sampled in urban areas. Our results revealed that precipitation may act as an important source of perchlorate, iodide and thiocyanate in surface water. Moreover, iodide concentrations in the Haihe River and Dagu Drainage Canal showed a good correlation with an ideal marker (acesulfame) of domestic waste water, indicating that input from domestic waste water was an important source of iodide in the surface waters of Tianjin. Copyright © 2014 Elsevier Ltd. All rights reserved.

Weakening of ice by magnesium perchlorate hydrate

USGS Publications Warehouse

Lenferinka, Hendrick J.; Durhama, William B.; Sternb, Laura A.; Patharec, Asmin V.

2013-01-01

We show that perchlorate hydrates, which have been detected at high circumpolar martian latitudes, have a dramatic effect upon the rheological behavior of polycrystalline water ice under conditions applicable to the North Polar Layered Deposits (NPLD). We conducted subsolidus creep tests on mixtures of ice and magnesium perchlorate hydrate, Mg(ClO4)2·6H2O (MP6), of 0.02, 0.05, 0.10, and 0.47 volume fraction MP6. We found these mixtures to be increasingly weak with increasing MP6 content. For mixtures with ⩽0.10 volume fraction MP6, we resolved a stress exponent of n ≈ 2 at low stresses transitioning to n ≈ 4 above 10 MPa. Scanning electron microscopy of deformed specimens revealed MP6 to be distributed as an interconnected film between ice grains. These results suggest that grain boundary sliding (GBS) may be enhanced with respect to pure ice. As the enhancement of GBS is expected in polycrystalline aggregates containing a few percent melt or otherwise weak material distributed along grain boundaries, the observed n ≈ 2 is consistent with the mutual accommodation of basal slip and GBS. If ice containing trace concentrations of MP6 is also much weaker than pure ice at low stresses, flow in the NPLD could be significantly enhanced, particularly at the warmer basal temperatures associated with higher martian obliquities.

ANALYSIS OF HYDROPONIC FERTILIZER MATRIXES FOR PERCHLORATE: COMPARISON OF ANALYTICAL TECHNIQUES

EPA Science Inventory

Seven retail hydroponic nitrate fertilizer products, two liquid and five solid, were comparatively analyzed for the perchlorate anion (ClO4-) by ion chromatography (IC) with suppressed conductivity detection, complexation electrospray ionization mass spectrometry (cESI-MS), norma...

POLISHING THE EFFLUENT FROM AN ANAEROBIC BIOLOGICAL PERCHLORATE TREATMENT PROCESS - SLIDES

EPA Science Inventory

Anaerobic biological processes effectively reduce perchlorate to chloride. However, the effluent can be biologically unstable, high in particulates and high in disinfection by-product precursor compounds. Such an effluent would be unsuitable for transmission into a drinking water...

Fractionation of stable isotopes in perchlorate and nitrate during in situ biodegradation in a sandy aquifer

USGS Publications Warehouse

Hatzinger, P.B.; Böhlke, J.K.; Sturchio, N.C.; Gu, B.; Heraty, L.J.; Borden, R.C.

2009-01-01

Environmental context. Perchlorate (ClO4-) and nitrate (NO3-) are common co-contaminants in groundwater, with both natural and anthropogenic sources. Each of these compounds is biodegradable, so in situ enhanced bioremediation is one alternative for treating them in groundwater. Because bacteria typically fractionate isotopes during biodegradation, stable isotope analysis is increasingly used to distinguish this process from transport or mixing-related decreases in contaminant concentrations. However, for this technique to be useful in the field to monitor bioremediation progress, isotope fractionation must be quantified under relevant environmental conditions. In the present study, we quantify the apparent in situ fractionation effects for stable isotopes in ClO4- (Cl and O) and NO3- (N and O) resulting from biodegradation in an aquifer. Abstract. An in situ experiment was performed in a shallow alluvial aquifer in Maryland to quantify the fractionation of stable isotopes in perchlorate (Cl and O) and nitrate (N and O) during biodegradation. An emulsified soybean oil substrate that was previously injected into this aquifer provided the electron donor necessary for biological perchlorate reduction and denitrification. During the field experiment, groundwater extracted from an upgradient well was pumped into an injection well located within the in situ oil barrier, and then groundwater samples were withdrawn for the next 30 h. After correction for dilution (using Br- as a conservative tracer of the injectate), perchlorate concentrations decreased by 78% and nitrate concentrations decreased by 82% during the initial 8.6 h after the injection. The observed ratio of fractionation effects of O and Cl isotopes in perchlorate (18O/37Cl) was 2.6, which is similar to that observed in the laboratory using pure cultures (2.5). Denitrification by indigenous bacteria fractionated O and N isotopes in nitrate at a ratio of ???0.8 (18O/15N), which is within the range of values

A low cost igniter utilizing an SCB and titanium sub-hydride potassium perchlorate pyrotechnic

NASA Technical Reports Server (NTRS)

Bickes, R. W., Jr.; Grubelich, M. C.; Hartman, J. K.; McCampbell, C. B.; Churchill, J. K.

1994-01-01

A conventional NSI (NASA Standard Initiator) normally employs a hot-wire ignition element to ignite ZPP (zirconium potassium perchlorate). With minor modifications to the interior of a header similar to an NSI device to accommodate an SCB (semiconductor bridge), a low cost initiator was obtained. In addition, the ZPP was replaced with THKP (titanium sub-hydride potassium perchlorate) to obtain increased overall gas production and reduced static-charge sensitivity. This paper reports on the all-fire and no-fire levels obtained and on a dual mix device that uses THKP as the igniter mix and a thermite as the output mix.

Catalytic and inhibiting effects of lithium peroxide and hydroxide on sodium chlorate decomposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cannon, J.C.; Zhang, Y.

1995-09-01

Chemical oxygen generators based on sodium chlorate and lithium perchlorate are used in airplanes, submarines, diving, and mine rescue. Catalytic decomposition of sodium chlorate in the presence of cobalt oxide, lithium peroxide, and lithium hydroxide is studied using thermal gravimetric analysis. Lithium peroxide and hydroxide are both moderately active catalysts for the decomposition of sodium chlorate when used alone, and inhibitors when used with the more active catalyst cobalt oxide.

Stripping analysis of nanomolar perchlorate in drinking water with a voltammetric ion-selective electrode based on thin-layer liquid membrane.

PubMed

Kim, Yushin; Amemiya, Shigeru

2008-08-01

A highly sensitive analytical method is required for the assessment of nanomolar perchlorate contamination in drinking water as an emerging environmental problem. We developed the novel approach based on a voltammetric ion-selective electrode to enable the electrochemical detection of "redox-inactive" perchlorate at a nanomolar level without its electrolysis. The perchlorate-selective electrode is based on the submicrometer-thick plasticized poly(vinyl chloride) membrane spin-coated on the poly(3-octylthiophene)-modified gold electrode. The liquid membrane serves as the first thin-layer cell for ion-transfer stripping voltammetry to give low detection limits of 0.2-0.5 nM perchlorate in deionized water, commercial bottled water, and tap water under a rotating electrode configuration. The detection limits are not only much lower than the action limit (approximately 246 nM) set by the U.S. Environmental Protection Agency but also are comparable to the detection limits of the most sensitive analytical methods for detecting perchlorate, that is, ion chromatography coupled with a suppressed conductivity detector (0.55 nM) or electrospray ionization mass spectrometry (0.20-0.25 nM). The mass transfer of perchlorate in the thin-layer liquid membrane and aqueous sample as well as its transfer at the interface between the two phases were studied experimentally and theoretically to achieve the low detection limits. The advantages of ion-transfer stripping voltammetry with a thin-layer liquid membrane against traditional ion-selective potentiometry are demonstrated in terms of a detection limit, a response time, and selectivity.

Trace detection of perchlorate in industrial-grade emulsion explosive with portable surface-enhanced Raman spectroscopy.

PubMed

Nuntawong, N; Eiamchai, P; Limwichean, S; Wong-ek, B; Horprathum, M; Patthanasettakul, V; Leelapojanaporn, A; Nakngoenthong, S; Chindaudom, P

2013-12-10

Recent analyses by ion-exchange chromatography (IC) showed that, beside nitrate, the majority of the industrial-grade emulsion explosives, extensively used by most separatists in the southern Thailand insurgency, contained small traces of perchlorate anions. In demand for the faster, reliable, and simple detection methods, the portable detection of nitrate and perchlorate became the great interest for the forensic and field-investigators. This work proposed a unique method to detect the trace amount of perchlorate in seven industrial-grade emulsion explosives under the field tests. We utilized the combination of the portable Raman spectroscope, the developed surfaced-enhanced Raman substrates, and the sample preparation procedures. The portable Raman spectroscope with a laser diode of 785 nm for excitation and a thermoelectric-cooled CCD spectrometer for detection was commercially available. The SERS substrates, with uniformly distributed nanostructured silver nanorods, were fabricated by the DC magnetron sputtering system, based on the oblique-angle deposition technique. The sample preparation procedures were proposed based on (1) pentane extraction technique and (2) combustion technique, prior to being dissolved in the purified water. In comparison to the ion chromatography and the conventional Raman measurements, our proposed methods successfully demonstrated the highly sensitive detectability of the minimal trace amount of perchlorate from five of the explosives with minimal operating time. This work was therefore highly practical to the development for the forensic analyses of the post-blast explosive residues under the field-investigations. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Intolerability of cobalt salt as erythropoietic agent.

PubMed

Ebert, Bastian; Jelkmann, Wolfgang

2014-03-01

Unfair athletes seek ways to stimulate erythropoiesis, because the mass of haemoglobin is a critical factor in aerobic sports. Here, the potential misuse of cobalt deserves special attention. Cobalt ions (Co(2+) ) stabilize the hypoxia-inducible transcription factors (HIFs) that increase the expression of the erythropoietin (Epo) gene. Co(2+) is orally active, easy to obtain, and inexpensive. However, its intake can bear risks to health. To elaborate this issue, a review of the pertinent literature was retrieved by a search with the keywords 'anaemia', 'cobalt', 'cobalt chloride', 'erythropoiesis', 'erythropoietin', 'Epo', 'side-effects' and 'treatment', amongst others. In earlier years, cobalt chloride was administered at daily doses of 25 to 300 mg for use as an anti-anaemic agent. Co(2+) therapy proved effective in stimulating erythropoiesis in both non-renal and renal anaemia, yet there were also serious medical adverse effects. The intake of inorganic cobalt can cause severe organ damage, concerning primarily the gastrointestinal tract, the thyroid, the heart and the sensory systems. These insights should keep athletes off taking Co(2+) to stimulate erythropoiesis. Copyright © 2013 John Wiley & Sons, Ltd.

Unconventional magnetisation texture in graphene/cobalt hybrids

DOE PAGES

Vu, A. D.; Coraux, J.; Chen, G.; ...

2016-04-26

Magnetic domain structure and spin-dependent reflectivity measurements on cobalt thin films intercalated at the graphene/Ir(111) interface are investigated using spin-polarised low-energy electron microscopy. We find that graphene-covered cobalt films have surprising magnetic properties. Vectorial imaging of magnetic domains reveals an unusually gradual thickness-dependent spin reorientation transition, in which magnetisation rotates from out-of-the-film plane to the in-plane direction by less than 10° per cobalt monolayer. During this transition, cobalt films have a meandering spin texture, characterised by a complex, three-dimensional, wavy magnetisation pattern. In addition, spectroscopy measurements suggest that the electronic band structure of the unoccupied states is essentially spin-independent alreadymore » a few electron-Volts above the vacuum level. These properties strikingly differ from those of pristine cobalt films and could open new prospects in surface magnetism.« less

Charge transfer complexes of adenosine-5‧-monophosphate and cytidine-5‧-monophosphate with water-soluble cobalt(II) Schiff base complexes in aqueous solution

NASA Astrophysics Data System (ADS)

Boghaei, Davar M.; Gharagozlou, Mehrnaz

2006-01-01

Water-soluble cobalt(II) tetradentate Schiff base complexes have been shown to form charge transfer (CT) complexes with a series of nucleoside monophosphates including adenosine-5‧-monophosphate (AMP) and cytidine-5‧-monophosphate (CMP). The investigated water-soluble cobalt(II) Schiff base complexes are (i) disodium[{bis(5-sulfo-salicylaldehyde)-o-phenylenediiminato}cobalt(II)], Na2[Co(SO3-salophen)] (1); (ii) disodium[{bis(5-sulfo-salicylaldehyde)-4,5-dimethyl-o-phenylenediiminato}cobalt(II)], Na2[Co(SO3-sal-4,5-dmophen)] (2) and (iii) disodium[{bis(4-methoxy-5-sulfo-salicylaldehyde)-4,5-dimethyl-o-phenylenediiminato}cobalt(II)], Na2[Co(SO3-4-meosal-4,5-dmophen)] (3). The formation constant and thermodynamic parameters for charge transfer complex formation of water-soluble cobalt(II) Schiff base complexes with nucleoside monophosphates were determined spectrophotometrically in aqueous solution at constant ionic strength (I = 0.2 mol dm-3 KNO3) under physiological condition (pH 7.0) and at various temperatures between 288 and 308 K. The stoichiometry has been found to be 1:1 (water-soluble cobalt(II) Schiff base complex: nucleoside monophosphate) in each case. Our spectroscopic and thermodynamic results show that the interaction of water-soluble cobalt(II) Schiff base complexes with the investigated nucleoside monophosphates occurs mainly through the phosphate group. The trend of the interaction according to the cobalt(II) Schiff base complexes due to electronic and steric factors is as follows: Na2[Co(SO3-salophen)] > Na2[Co(SO3-sal-4,5-dmophen)] > Na2[Co(SO3-4-meosal-4,5-dmophen)]. Also the trend of the interaction of a given cobalt(II) Schiff base complex according to the nucleoside monophosphate is as follows: CMP > AMP.

Consumer leather exposure: an unrecognized cause of cobalt sensitization.

PubMed

Thyssen, Jacob P; Johansen, Jeanne D; Jellesen, Morten S; Møller, Per; Sloth, Jens J; Zachariae, Claus; Menné, Torkil

2013-11-01

A patient who had suffered from persistent generalized dermatitis for 7 years was diagnosed with cobalt sensitization, and his leather couch was suspected as the culprit, owing to the clinical presentation mimicking allergic chromium dermatitis resulting from leather furniture exposure. The cobalt spot test, X-ray fluorescence, inductively coupled plasma mass spectrometry and scanning electron microscopy were used to determine cobalt content and release from the leather couch that caused the dermatitis and from 14 randomly collected samples of furniture leather. The sample from the patient's leather couch, but none of the 14 random leather samples, released cobalt in high concentrations. Dermatitis cleared when the patient stopped using his couch. Cobalt is used in the so-called pre-metallized dyeing of leather products. Repeated studies have found high levels of cobalt sensitization, but not nickel sensitization, in patients with foot dermatitis. We raise the possibility that cobalt may be widely released from leather items, and advise dermatologists to consider this in patients with positive cobalt patch test reactions. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cobalt poisoning

MedlinePlus

... This type of implant is an artificial hip socket that is created by fitting a metal ball ... particles (ions) can get released into the hip socket and sometimes the bloodstream, causing cobalt toxicity. This ...

Deflagration-to-detonation characteristics of a laser exploding bridge detonator

NASA Astrophysics Data System (ADS)

Welle, E. J.; Fleming, K. J.; Marley, S. K.

2006-08-01

Evaluation of laser initiated explosive trains has been an area of extreme interest due to the safety benefits of these systems relative to traditional electro-explosive devices. A particularly important difference is these devices are inherently less electro-static discharge (ESD) sensitive relative to traditional explosive devices due to the isolation of electrical power and associated materials from the explosive interface. This paper will report work conducted at Sandia National Laboratories' Explosive Components Facility, which evaluated the initiation and deflagration-to-detonation characteristics of a Laser Driven Exploding Bridgewire detonator. This paper will report and discuss characteristics of Laser Exploding Bridgewire devices loaded with hexanitrohexaazaisowurtzitane (CL-20) and tetraammine-cis-bis-(5-nitro-2H-tetrazolato-N2) cobalt (III) perchlorate (BNCP).

21 CFR 73.1015 - Chromium-cobalt-aluminum oxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Identity. The color additive chromium-cobalt-aluminum oxide is a blue-green pigment obtained by calcining a... percent each) of oxides of barium, boron, silicon, and nickel. (b) Specifications. Chromium-cobalt... milliliters of 0.5 N hydrochloric acid. (c) Uses and restrictions. The color additive chromium-cobalt-aluminum...

All-Atom MD Simulation of DNA Condensation Using Ab Initio Derived Force Field Parameters of Cobalt(III)-Hexammine.

PubMed

Sun, Tiedong; Mirzoev, Alexander; Korolev, Nikolay; Lyubartsev, Alexander P; Nordenskiöld, Lars

2017-08-24

It is well established that the presence of the trivalent cobalt(III)-hexammine cation (CoHex 3+ ) at submillimolar concentrations leads to bundling (condensation) of double-stranded DNA molecules, which is caused by DNA-DNA attraction induced by the multivalent counterions. However, the detailed mechanism of this process is still not fully understood. Furthermore, in all-atom molecular dynamics (MD) simulations, spontaneous aggregation of several DNA oligonucleotides in the presence of CoHex 3+ has previously not been demonstrated. In order to obtain a rigorous description of CoHex 3+ -nucleic acid interactions and CoHex 3+ -induced DNA condensation to be used in MD simulations, we have derived optimized force field parameters of the CoHex 3+ ion. They were obtained from Car-Parrinello molecular dynamics simulation of a single CoHex 3+ ion in the presence of 125 water molecules. The new set of force field parameters reproduces the experimentally known transition of DNA from B- to A-form, and qualitatively describes changes of DNA and RNA persistence lengths. We then carried out a 2 μs long atomistic simulation of four DNA oligomers each consisting of 36 base pairs in the presence of CoHex 3+ . We demonstrate that, in this system, DNA molecules display attractive interactions and aggregate into bundle-like structures. This behavior depends critically on the details of the CoHex 3+ interaction with DNA. A control simulation with a similar setup but in the presence of Mg 2+ does not induce DNA-DNA attraction, which is also in agreement with experiment.

Mechanism of H2S Oxidation by the Dissimilatory Perchlorate-Reducing Microorganism Azospira suillum PS.

PubMed

Mehta-Kolte, Misha G; Loutey, Dana; Wang, Ouwei; Youngblut, Matthew D; Hubbard, Christopher G; Wetmore, Kelly M; Conrad, Mark E; Coates, John D

2017-02-21

The genetic and biochemical basis of perchlorate-dependent H 2 S oxidation (PSOX) was investigated in the dissimilatory perchlorate-reducing microorganism (DPRM) Azospira suillum PS (PS). Previously, it was shown that all known DPRMs innately oxidize H 2 S, producing elemental sulfur (S o ). Although the process involving PSOX is thermodynamically favorable ( ΔG °' = -206 kJ ⋅ mol -1 H 2 S), the underlying biochemical and genetic mechanisms are currently unknown. Interestingly, H 2 S is preferentially utilized over physiological electron donors such as lactate or acetate although no growth benefit is obtained from the metabolism. Here, we determined that PSOX is due to a combination of enzymatic and abiotic interactions involving reactive intermediates of perchlorate respiration. Using various approaches, including barcode analysis by sequencing (Bar-seq), transcriptome sequencing (RNA-seq), and proteomics, along with targeted mutagenesis and biochemical characterization, we identified all facets of PSOX in PS. In support of our proposed model, deletion of identified upregulated PS genes traditionally known to be involved in sulfur redox cycling (e.g., Sox, sulfide:quinone reductase [SQR]) showed no defect in PSOX activity. Proteomic analysis revealed differential abundances of a variety of stress response metal efflux pumps and divalent heavy-metal transporter proteins, suggesting a general toxicity response. Furthermore, in vitro biochemical studies demonstrated direct PSOX mediated by purified perchlorate reductase (PcrAB) in the absence of other electron transfer proteins. The results of these studies support a model in which H 2 S oxidation is mediated by electron transport chain short-circuiting in the periplasmic space where the PcrAB directly oxidizes H 2 S to S o The biogenically formed reactive intermediates (ClO 2 - and O 2 ) subsequently react with additional H 2 S, producing polysulfide and S o as end products. IMPORTANCE Inorganic sulfur

Cis Effects in the Cobalt Corrins. 1. Crystal Structures of 10-Chloroaquacobalamin Perchlorate, 10-Chlorocyanocobalamin, and 10-Chloromethylcobalamin.

PubMed

Brown, Kenneth L.; Cheng, Shifa; Zou, Xiang; Zubkowski, Jeffrey D.; Valente, Edward J.; Knapton, Leanne; Marques, Helder M.

1997-08-13

The crystal structures of 10-chloroaquacobalamin perchlorate hydrate (10-Cl-H(2)OCbl.ClO(4)) (Mo Kalpha, 0.710 73 Å, monoclinic system, P2(1), a = 11.922(4) Å, b = 26.592(10) Å, c = 13.511(5) Å, beta = 93.05(3) degrees, 10 535 independent reflections, R(1) = 0.0426), 10-chlorocyanocobalamin-acetone hydrate (10-Cl-CNCbl) (Mo Kalpha, 0.710 73 Å, orthorhombic system, P2(1)2(1)2(1), a = 16.24(3) Å, b = 21.85(5) Å, c = 26.75(8) Å, 7699 independent reflections, R(1) = 0.0698), and 10-chloromethylcobalamin-acetone hydrate (10-Cl-MeCbl) (Mo Kalpha, 0.71073 Å, orthorhombic system, P2(1)2(1)2(1), a = 16.041(14) Å, b = 22.13(2) Å, c = 26.75(4) Å, 6792 independent reflections, R(1) = 0.0554), in which the C10 meso H is substituted by Cl, are reported. An unusual feature of the structures is disorder in the C ring, consistent with a two-site occupancy in which the major conformation has the C46 methyl group in the usual position, "upwardly" axial, and the C47 methyl group equatorial, while in the minor conformation both are pseudoequatorial, above and below the corrin ring. (13)C NMR chemical shifts of C46, C47, C12, and C13 suggest that the C ring disorder may persist in solution as a ring flip. Since molecular dynamics simulations fail to reveal any population of the minor conformation, the effect is likely to be electronic rather than steric. The axial bond lengths in 10-Cl-MeCbl are very similar to those in MeCbl (d(Co)(-)(C) = 1.979(7) vs 1.99(2); to 5,6-dimethylbenzimidazole, d(Co)(-)(NB3) = 2.200(7) vs 2.19(2)), but the bonds to the four equatorial N donors, d(Co)(-)(N(eq)), are on average 0.05 Å shorter. In 10-Cl-CNCbl, d(Co)(-)(C) and d(Co)(-)(NB3) are longer (by 0.10(2) and 0.03(1) Å, respectively) than the bond lengths observed in CNCbl itself, while conversely, the C-N bond length is shorter by 0.06(2) Å, but there is little difference in d(Co)(-)(N(eq)). The Co-O bond length to coordinated water in 10-Cl-H(2)OCbl(+) is very similar to that found in H

REPORT ON THE PEER REVIEW OF THE U.S. EPA'S "Perchlorate ENVIRONMENTAL CONTAMINATION: TOXICOLOGICAL REVIEW AND RISK CHARACTERIZATION (External Review Draft)" 2002

EPA Science Inventory

This report summarizes the comments made at a two-day independent scientific peer review meeting on the Agency's draft assessment of health and ecotoxicological effects of perchlorate, entitled Perchlorate Environmental Contamination: Toxicological Review and Risk Characteriza...