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NO3
Kinds of NO3 Selected AbstractsSolvothermal production of CdS nanorods using polyvinylpyrrolidone as a templateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2009Titipun Thongtem Abstract CdS nanorods were solvothermally produced using Cd(NO3)2 and S powder in ethylenediamine containing different amounts of polyvinylpyrrolidone (PVP). The phase with hexagonal structure was detected using X-ray diffraction (XRD) and selected area electron diffraction (SAED). Their SAED patterns were in accordance with those of the simulations. Scanning and transmission electron microscopies (SEM and TEM) revealed the presence of CdS nanorods with their lengths influenced by different amounts of PVP. The nanorods were also characterized using high resolution TEM (HRTEM). They grew in the [001] direction normal to the (002) parallel crystallographic planes composing the nanorods. Raman spectra showed the 1LO (first harmonic) and 2LO (second harmonic) modes at the same wavenumbers although the products were produced under different conditions. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Microhardness studies on as-grown (111) faces of some alkaline earth nitratesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2009P. V. Raja Shekar Abstract Single crystals of Sr(NO3)2, Ba(NO3)2 and Pb(NO3)2 are grown from their aqueous solutions at a constant temperature of 35 °C by slow evaporation technique. Crystals of size 8 to 10 mm along one edge are obtained in a period of 10 days. Chemical etching technique has been employed to study the dislocations in these crystals. The dislocations are randomly distributed and the dislocation density is about 104 to 105 /cm2. Microhardness studies are made on as,grown (111) faces of these crystals upto a load of 100 g. The hardness of the crystals increases with an increase in load and thereafter it becomes independent of the applied load. These results are discussed on the basis of reverse indentation size effect. Meyer index number n for these crystals is estimated at both low and high load regions. An analysis of hardness data of these crystals as well as some other cubic crystals like alums and alkali halates are discussed using Gilman,Chin parameter Hv/C44, where Hv is the microhardness and C44 is the shear constant. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis, structure and photoluminescence of a 3D pillared heterometallic coordination polymer containing 2D inorganic cadmium-potassium-oxide layer subunitsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2009Qing-Yan Liu Abstract Self-assembly of Cd(NO3)2 with o -phthalic acid monopotassium salt (KHphth) in the presence of ethylenediamine (en) produced a new heterometallic coordination polymer [CdK2(phth)2(en)0.5(H2O)]n (1). Single-crystal X-ray analyses reveal that it crystallizes in a monoclinic space group P 21/c. a = 11.6707(6) Å, b = 8.1019(4) Å, c = 20.9503(11) Å, , = 94.6640(10)o. The complex displays an en-pillared 3D framework, which is constructed from 2D [CdK2(phth)2(H2O)]n layers featuring uncommon inorganic cadmium-potassium-oxide layers containing potassium-oxide layers. In the solid state, complex 1 shows photoluminescence with the maximum emission intensities at 355 nm upon excitation at 312 nm. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis and crystal strcucture of two zinc inclusion complexesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2008Min-Le Han Abstract X-ray single crystals of these two inclusion complexes, [Zn(H2O)4L2]·(4-amino-1-naphthalene sulfonate)2 (L = 1,3-bis(4-pyridyl) propane), 1, and [Zn(H2O)(bipy)2]·(4-amino-1-naphthalene sulfonate)(NO3) (bipy = 4,4'-bipyridine), 2 were achieved by the reaction of Zn(NO3)2 and 4-amino-1-naphthalene sulfonate to 1,3-bis(4-pyridyl) propane and 4,4'-bipyridine, respectively. As inclusion complexes, the cationic components of 1 and 2 were formed by two infinite zigzag chains, while, 4-amino-1-naphthalene sulfonate made up the anionic parts of these two complexes. Thus, the whole molecules of these two complexes are neuter. Numous hydrogen bonds could be found in these two inclusion complexes, which help them to form three-dimensional solid-state packing structure architectures. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Zinc and nitrate in the ground water and the incidence of Type 1 diabetes in FinlandDIABETIC MEDICINE, Issue 3 2004E. Moltchanova Abstract Aims In Finland, the risk of childhood Type 1 diabetes varies geographically. Therefore we investigated the association between spatial variation of Type 1 diabetes and its putative environmental risk factors, zinc and nitrates. Methods The association was evaluated using Bayesian modelling and the geo-referenced data on diabetes cases and population. Results Neither zinc nor nitrate nor the urban/rural status of the area had a significant effect on the variation in incidence of childhood Type 1 diabetes. Conclusions The results showed that although there was no significant difference in incidence between rural and urban areas, there was a tendency to increasing risk of Type 1 diabetes with the increasing concentration of NO3 in drinking water. The fact that no significant effect was found may stem from the aggregated data being too crude to detect it. [source] The Determination of Methanol Using an Electrolytically Fabricated Nickel Microparticle Modified Boron Doped Diamond ElectrodeELECTROANALYSIS, Issue 5 2010Kathryn Abstract A nickel modified boron doped diamond (Ni-BDD) electrode and nickel foil electrode were used in the determination of methanol in alkaline solutions. The Ni-BDD electrode was electrodeposited from a 1,mM Ni(NO3)2 solution (pH,5), followed by repeat cycling in KOH. Subsequent analysis utilised the Ni(OH)2/NiOOH redox couple to electrocatalyse the oxidation of methanol. Methanol was determined to limits of 0.3,mM with a sensitivity of 110,nA/mM at the Ni-BDD electrode. The foil electrode was less sensitive achieving a limit of 1.6,mM and sensitivity of 27,nA/mM. SEM analysis of the electrodes found the Ni-BDD to be modified by a quasi-random microparticle array. [source] Novel Thorium Membrane Sensors with Anionic Response Based on Trioctylphosphine Oxide and Toluate IonophoresELECTROANALYSIS, Issue 19 2008Abstract Two novel potentiometric polymeric membrane sensors for rapid and accurate determination of thorium are described. These are based on the use of trioctylphosphine oxide (TOPO) and thorium toluate (Th-TA) as ionophores dispersed in poly(vinyl chloride) matrix membranes plasticized with nitrophenyloctyl ether. In strong nitric acid medium, Th(IV) nitrate is converted into [Th(NO3)6]2, complex and sensed as anionic divalent ion which exclude most cationic effect. Validation of the assay methods using the quality assurance standards (linearity range, accuracy, precision, within-day variability, between-day-repeatability, lower detection limit and sensitivity) reveals excellent performance characteristics of both sensors. The sensors exhibit near-Nernstian response for 1.0×10,6,1.0×10,1 M Th over the pH range 2.5,4.5. Calibration slopes of ,32.3±0.3 and ,27.2±0.2,mV/decade, precision of ±0.5 and ±0.8% and accuracy of 98.8±0.9 and 97.9±0.7% are obtained with TOPO and Th-TA based sensors, respectively. Negligible interferences are caused by most interfering mono-, di-, tri-, tetra-, penta-, and hexa-valent elements commonly associated with thorium in naturally occurring minerals and ores. High concentrations of Cl,, F,, SO42,, and NO3, ions have no diverse effect. Complete removal of the effect of the interferents in complex matrices is achieved by retention of [Th(NO3)6]2, complex from 5,M nitric acid/methanol mixture (1,:,9,v/v) on a strong anion exchanger, washing out the cationic interferents followed by stripping off thorium anion complex and measurements. Both sensors are used for determining thorium in certified thorium ore samples (20,120,mg Th/kg) and some naturally occurring ores (200,600,mg Th/kg). The results obtained agree fairly well with the certified labeled values or the data obtained using X-ray fluorescence spectrometry [source] The Fabrication and Characterization of a Bismuth Nanoparticle Modified Boron Doped Diamond Electrode and Its Application to the Simultaneous Determination of Cadmium(II) And Lead(II)ELECTROANALYSIS, Issue 16 2008Kathryn Abstract We report the simultaneous electroanalytical determination of Pb2+ and Cd2+ by square-wave anodic stripping voltammetry (SWASV) using a bismuth nanoparticle modified boron doped diamond (Bi-BDD) electrode. Bi deposition was performed in situ with the analytes, from a solution of 0.1,mM Bi(NO3)3 in 0.1,M HClO4 (pH,1.2), and gave detection limits of 1.9,,g L,1 and 2.3,,g L,1 for Pb(II) and Cd(II) respectively. Pb2+ and Cd2+ could not be detected simultaneously at a bare BDD electrode, whilst on a bulk Bi macro electrode (BiBE) the limits of detection for the simultaneous determination of Pb2+ and Cd2+ were ca. ten times higher. [source] A Cobalt Film Electrode for Nitrite Determination in Natural WaterELECTROANALYSIS, Issue 24 2007Koïkoï Soropogui Abstract In this study a cobalt film electrodeposited on a copper disk (Ø=3.1,mm) was tested as electrode to measure nitrite ions in raw water. This electrode was able to determine the nitrite ions concentration in nondeaerated synthetic media and in natural water. The electrode reached a detection limit of 0.2,,mol L,1 and has a linear concentration range of 0.4 to 2,,mol L,1 NO2,. The influence of several ions such as NO3,, Cl,, SO42,, Mg2+, HCO3, and NH4+ was also tested. The electrode was used to determine the concentration of nitrite ions in a real sample. [source] Bismuth Film Electrode as an Alternative for Mercury Electrodes: Determination of Azo Dyes and Application for Detection in Food StuffsELECTROANALYSIS, Issue 21 2007Benoît Claux Abstract Bismuth electrodes were investigated and exhibit electrochemical properties similar to mercury electrodes but with much lower toxicity. An electrochemical application of bismuth film modified glassy carbon electrode for azo dyes determination was investigated. The plating step was optimized in order to achieve its analytical efficiency. A plating potential of ,0.9,V in a solution of 200,mg/L Bi(NO3)3, 0.5,M HNO3 for 100,s yields to a suitable electrode (in terms of stability and detection). Azo dyes such as azorubine (i.e., carmoisine, E122), amaranth (E123), ponceau 4R (i.e., new coccine, E124) and allura red (E129) were determined by differential pulse voltammetry in a NaCl solution in the concentration range of few ppm to 100 ppm. The reproducibility of the signal, characterized by the relative standard deviation, was found to be less than 5%, the detection and quantification limits were few mg/L. The influence of other food components on the signal was studied and the applicability was tested on real beverages samples. [source] Zinc Oxide/Zinc Hexacyanoferrate Hybrid Film-Modified Electrodes for Guanine DetectionELECTROANALYSIS, Issue 18 2007Hung-Wei Chu Abstract An electroactive polynuclear hybrid films of zinc oxide and zinc hexacyanoferrate (ZnO/ZnHCF) have been deposited on electrode surfaces from H2SO4 solution containing Zn(NO3)2 and K3[Fe(CN)6] by repetitive potential cycling method. Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) measurements demonstrate the steady growth of hybrid film. There are two redox couples present in the voltammograms of hybrid film and it is obvious in the case of pH,2. Surface morphology of hybrid film was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Energy dispersive spectrometer (EDS) data confirm existence of zinc oxide in the hybrid film. The effect of type of monovalent cations on the redox behavior of resulting film was investigated. In pure supporting electrolyte, electrochemical responses of modified electrode resemble with that of a surface immobilized redox couple. The electrocatalytic activity of ZnO/ZnHCF hybrid film was investigated towards guanine using cyclic voltammetry and rotating disc electrode (RDE) techniques. Finally, feasibility of using ZnO/ZnHCF hybrid film-coated electrodes for guanine estimation in flow injection analysis (FIA) was also investigated. [source] Electrochemical Investigation of the Role of Reducing Agents in Copper-Catalyzed Nitric Oxide Release from S-NitrosoglutathioneELECTROANALYSIS, Issue 18 2006Monique David-Dufilho Abstract Studies of nitric oxide (NO) release from S -nitrosoglutathione (GSNO) decomposition by Cu2+ in the presence of reducing agents were performed using a nickel porphyrin and Nafion-coated microsensor in order to compare the efficiency of sodium hydrosulfite (Na2S2O4) and sodium borohydride (NaBH4) to that of the most abundant endogenous reducer, glutathione (GSH). When it was mixed to Cu(NO3)2 and added to equimolar concentration of GSNO, each reducing agent caused a NO release (measured in terms of oxidation current) but only NaBH4 induced a proportional rise if its concentration doubled and that of Cu2+ remained constant. For Na2S2O4, there was a mild increase and for GSH, no change. Furthermore, when Cu2+ concentrations ranging from 0.5 to 5,,M were mixed with 2,,M reducing agent and added to 2,,M GSNO, the NO oxidation current linearly increased with NaBH4 and was constant with Na2S2O4. Concerning GSH, Cu2+ dose-dependently increased the NO release from GSNO only if the Cu2+ -to-reducer ratio was ,1. However, GSH formed the catalytic species Cu+ even in excess of Cu2+ and GSNO as indicated by suppression of the Cu2+/GSH-induced NO release when the Cu+ chelator neocuproine was added to GSNO. This work shows that, among the 3 reducing agents, only NaBH4 allows Cu2+ to dose-dependently increase the NO release from GSNO for Cu2+ -to-reducer ratios ranging from 0.25 to 2.5. Despite this good effectiveness, excess of NaBH4 compared to both Cu2+ and GSNO seems to be required for optimal NO release. [source] Aluminum(III) Porphyrins as Ionophores for Fluoride Selective Polymeric Membrane ElectrodesELECTROANALYSIS, Issue 6 2006Jeremy Abstract Aluminum(III) porphyrins are examined as potential fluoride selective ionophores in polymeric membrane type ion-selective electrodes. Membranes formulated with Al(III) tetraphenyl (TPP) or octaethyl (OEP) porphyrins are shown to exhibit enhanced potentiometric selectivity for fluoride over more lipophilic anions, including perchlorate and thiocyanate. However, such membrane electrodes display undesirable super-Nernstian behavior, with concomitant slow response and recovery times. By employing a sterically hindered Al(III) picket fence porphyrin (PFP) complex as the membrane active species, fully reversible and Nernstian response toward fluoride is achieved. This finding suggests that the super-Nernstian behavior observed with the nonpicket fence metalloporphyrins is due to the formation of aggregate porphyrin species (likely dimers) within the membrane phase. The steric hindrance of the PFP ligand structure eliminates such chemistry, thus leading to theoretical response slopes toward fluoride. Addition of lipophilic anionic sites into the organic membranes enhances response and selectivity, indicating that the Al(III) porphyrin ionophores function as charged carrier type ionophores. Optimized membranes formulated with Al(III)-PFP in an o -nitrophenyloctyl ether plasticized PVC film exhibit fast response to fluoride down to 40,,M, with very high selectivity over SCN,, ClO4,, Cl,, Br, and NO3, (kpot<10,3 for all anions tested). With further refinements in the membrane chemistry, it is anticipated that Al(III) porphyrin-based membrane electrodes can exhibit potentiometric fluoride response and selectivity that approaches that of the classical solid-state LaF3 crystal-based fluoride sensor. [source] Evaluation of Cu,Ethylenediamine Metal Ion Buffers as Calibrants for Ion-Selective Electrode Measurement of Copper in Fresh Water SystemsELECTROANALYSIS, Issue 10 2005Ling Zeng Abstract An investigation was made into the accuracy of cupric ion selective electrode (ISE) measurement of Cu in solutions approximating acidic freshwaters with Cu-ethylenediamine buffers used as the calibrants. This method overestimates the free Cu compared with calibration using Cu(NO3)2 standards, the standard addition method, and speciation modelling calculations. Statistical tests showed a small, but significant, difference between the intercepts of the linear Nernstian regressions of the calibration plots of Cu-en buffer standardisation and direct calibration with Cu(NO3)2 standards in matrix that matches the samples. The difference in the intercepts, which corresponds with Eo values of the electrode, is not well understood, but is possibly caused by potentially interfering cations such as Fe2+. The results of this study showed that down to 10,8,M Cu2+, where a linear Nernstian response is possible, the Cu ISE is probably better calibrated using Cu standards prepared in the same matrix as the sample solutions to avoid potential matrix effects. [source] Determination of nitrate and nitrite in rat brain perfusates by capillary electrophoresisELECTROPHORESIS, Issue 9 2004Leyi Gao Abstract A fast and simple method for the direct, simultaneous detection of nitrite (NO2,) and nitrate (NO3,) in rat striatum has been developed using a capillary electrophoresis separation of low-flow push-pull perfusion samples. The method was optimized primarily for nitrite because nitrite is more important physiologically and is found at lower levels than nitrate. We obtained a complete separation of NO2, and NO3, in rat striatum within 1.5 min. Optimal CE separations were achieved with 20 mM phosphate, 2 mM cetyltrimethylammonium chloride (CTAC) buffer at pH 3.5. The samples were injected electrokinetically for 2 s into a 40 cm×75 ,m ID fused-silica capillary. The separation voltage was 10 kV (negative polarity), and the injection voltage was 16 kV (negative polarity). UV detection was performed at 214 nm. The limits of detection obtained at a signal-to-noise ratio (S/N) of 3 for nitrite and nitrate were 0.96 and 2.86 ,M. This is one of the fastest separations of nitrite and nitrate of a biological sample ever reported. Interference produced by the high physiological level of chloride is successfully minimized by use of CTAC in the run buffer. [source] Anaerobic arsenite oxidation by novel denitrifying isolatesENVIRONMENTAL MICROBIOLOGY, Issue 5 2006E. Danielle Rhine Summary Autotrophic microorganisms have been isolated that are able to derive energy from the oxidation of arsenite [As(III)] to arsenate [As(V)] under aerobic conditions. Based on chemical energetics, microbial oxidation of As(III) can occur in the absence of oxygen, and may be relevant in some environments. Enrichment cultures were established from an arsenic contaminated industrial soil amended with As(III) as the electron donor, inorganic C as the carbon source and nitrate as the electron acceptor. In the active enrichment cultures, oxidation of As(III) was stoichiometrically coupled to the reduction of NO3,. Two autotrophic As(III)-oxidizing strains were isolated that completely oxidized 5 mM As(III) within 7 days under denitrifying conditions. Based on 16S rRNA gene sequencing results, strain DAO1 was 99% related to Azoarcus and strain DAO10 was most closely related to a Sinorhizobium. The nitrous oxide reductase (nosZ) and the RuBisCO Type II (cbbM) genes were successfully amplified from both isolates underscoring their ability to denitrify and fix CO2 while coupled to As(III) oxidation. Although limited work has been done to examine the diversity of anaerobic autotrophic oxidizers of As(III), this process may be an important component in the biological cycling of arsenic within the environment. [source] Anaerobic redox cycling of iron by freshwater sediment microorganismsENVIRONMENTAL MICROBIOLOGY, Issue 1 2006Karrie A. Weber Summary The potential for microbially mediated anaerobic redox cycling of iron (Fe) was examined in a first-generation enrichment culture of freshwater wetland sediment microorganisms. Most probable number enumerations revealed the presence of significant populations of Fe(III)-reducing (approximately 108 cells ml,1) and Fe(II)-oxidizing, nitrate-reducing organisms (approximately 105 cells ml,1) in the freshwater sediment used to inoculate the enrichment cultures. Nitrate reduction commenced immediately following inoculation of acetate-containing (approximately 1 mM) medium with a small quantity (1% v/v) of wetland sediment, and resulted in the transient accumulation of NO2, and production of a mixture of gaseous end-products (N2O and N2) and NH4+. Fe(III) oxide (high surface area goethite) reduction took place after NO3, was depleted and continued until all the acetate was utilized. Addition of NO3, after Fe(III) reduction ceased resulted in the immediate oxidation of Fe(II) coupled to reduction of NO3, to NH4+. No significant NO2, accumulation was observed during nitrate-dependent Fe(II) oxidation. No Fe(II) oxidation occurred in pasteurized controls. Microbial community structure in the enrichment was monitored by denaturing gradient gel electrophoresis analysis of polymerase chain reaction-amplified 16S rDNA and reverse transcription polymerase chain reaction-amplified 16S rRNA, as well as by construction of 16S rDNA clone libraries for four different time points during the experiment. Strong similarities in dominant members of the microbial community were observed in the Fe(III) reduction and nitrate-dependent Fe(II) oxidation phases of the experiment, specifically the common presence of organisms closely related (, 95% sequence similarity) to the genera Geobacter and Dechloromonas. These results indicate that the wetland sediments contained organisms such as Geobacter sp. which are capable of both dissimilatory Fe(III) reduction and oxidation of Fe(II) with reduction of NO3, to NH4+. Our findings suggest that microbially catalysed nitrate-dependent Fe(II) oxidation has the potential to contribute to a dynamic anaerobic Fe redox cycle in freshwater sediments. [source] Long-term stability of biological denitrification process for high strength nitrate removal from wastewater of uranium industryENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2008Prashant M. Biradar Abstract The aim of the present study was to biologically denitrify uranium nitrate raffinate (UNR) from nuclear industry, which is a principle source of high strength nitrate waste. To denitrify the high nitrate waste, a pilot-scale continuous stirred tank reactor was designed with two inbuilt settlers. Acclimatization of mixed culture with synthetic waste was carried out prior to the inoculation of the acclimatized sludge into the reactor. Initial concentration of nitrate in uranium raffinate was 77,000 mg/L NO3. It was diluted and used as a feed to the reactor. Concentration of nitrate in feed was increased gradually from 10,000 mg/L NO3 to 40,000 mg/L NO3 with hydraulic retention time (HRT) maintained at 34.4 h. Complete denitrification of 40,000 mg/L NO3 was achieved in a specified HRT. To facilitate understanding of the treatablity and long-term stability of biological denitrification of UNR, study was carried out for 211 days by periodical perturbation of the system. Furthermore, to find the volume ratio of reactor to settler required for the full-scale design of the denitrification plant, settling of acclimatized sludge was carried out. © 2008 American Institute of Chemical Engineers Environ Prog, 2008 [source] Characteristics of microcystin production in the cell cycle of Microcystis viridisENVIRONMENTAL TOXICOLOGY, Issue 1 2004Keishi Kameyama Abstract The correlation between the content of three microcystins (types LR, RR and YR) and the cell cycle of an axenic strain of Microcystis viridis, NIES-102, was investigated under conditions of high (16 mg L,1) and low (1.0 mg L,1) nitrate (NO3 -N) concentrations. Each phase of the cell cycle was identified using a flow cytometer equipped with a 488-nm argon laser using SYTOX Green dye, which binds specifically to nucleic acids and can be exited by the wavelength (Ex/Em: 504/523 nm on DNA). Microcystin concentration showed a positive linear correlation with DNA concentration. The microcystin content of the cells changed remarkably as the cell cycle process proceeded, with maximum content in the G2/M phase and minimum content in the G0/G1 phase. Under a condition of high NO3 -N concentration, the ratio of the total content in the G0/G1 phase to that in the G2/M phase was about 6:1. In contrast, for the two batch cultures the total content was 1.3-fold greater in the G2/M phase. The compositions of the three microcystins also changed along with the cell cycle process, although there was little difference in composition that was related to NO3 -N concentration. Therefore, there were distinctive compositions specific to each phase of the cycle, and the cell cycle of the M. viridis strain was more strongly responsible for both the quantity and the types of microcystin production than was the effect of NO3 -N concentration. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 20,25, 2004. [source] Determining toxicity of lead and zinc runoff in soils: Salinity effects on metal partitioning and on phytotoxicityENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2003Daryl P. Stevens Abstract When assessingcationic metal toxicity in soils, metals are often added to soil as the chloride, nitrate, or sulfate salts. In many studies, the effects of these anions are ignored or discounted; rarely are appropriate controls included. This study used five soils varying in pH, clay content, and organic matter to determine whether salinity from counter-ions contributed to or confounded metal phytotoxicity. Varying rates of Pb and Zn were applied to soils with or without a leaching treatment to remove the metal counter-ion (NO3 -). Lactuca sattva (lettuce) plants were grown in metal-treated soils, and plant dry weights were used to determine median effective concentrations where there was a 50% reduction in yield (EC50s) on the basis of total metals measured in the soil after harvest. In two of the five soils, leaching increased the EC50s significantly for Zn by 1.4- to 3.7-fold. In three of the five soils, leaching increased the EC50s significantly for Pb by 1.6- to 3.0-fold. The shift in EC50s was not a direct result of toxicity of the nitrate ion but was an indirect effect of the salinity increasing metal concentrations in soil solution and increasing its bioavailability for a given total metal concentration. In addition, calculation of potential salinity changes in toxicological studies from the addition of metals exhibiting strong sorption to soil suggested that if the anion associated with the metal is not leached from the soil, direct salinity responses could also lead to significant overestimation of the EC50 for those metals. These findings question the relevance of the application of single-metal salts to soils as a method of assessing metal phytotoxicity when, in many cases in our environment, Zn and Pb accumulate in soil over a period of time and the associated counter-ions are commonly removed from the soil during the accumulation process (e.g., roof and galvanized tower runoff). [source] Changes in toxicity and bioavailability of lead in contaminated soils to the earthworm Eisenia fetida (savigny 1826) after bone meal amendments to the soilENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2002Nicola A. Davies Abstract The effect of bone meal (Ca5(PO4)3OH) amendments on lead (Pb) bioavailability to Eisenia fetida (Savigny 1826) was investigated. A standard uncontaminated soil was amended with Pb(NO3)2 solution to give Pb concentrations of 7,000 ,g/g of soil. After one week, bone meal was added to one half of the soil in the ratio 1:20 bone meal:soil. Immediately after addition of the bone meal, survival times of E. fetida were 23 and 41 h in the bone meal-free and bone meal-amended soil, respectively. Twentyeight days after addition of the bone meal, survival times of Eisenia fetida were 67 h in the bone meal-free soil and more than 168 h in the bone meal-amended soil. In a second experiment, a standard Organisation for Economic Co-operation and Development reproduction toxicity test was carried out, but in addition to Pb(NO3)2 solution, bone meal was added to the soil in the ratio 1:20 bone meal:soil. The bone meal-free soil was left for five weeks before addition of E. fetida. In the bone meal-amended soil, bon emeal was added to the soil one week after addition of the Pb. The soil was left for a further four weeks before addition of Eisenia fetida. Calculated toxicities were significantly lower for the bone meal-amended soil than those calculated for the bone meal-free soil. Twenty-eight-day median lethal concentrations (LC50s; concentration that is statistically likely to kill 50% of the exposed test organism within a given time period ± 95% confidence intervals) of Pb were 4,379 ± 356 ,g/g of soil for bone meal-free soil and 5,203 ± 401 ,g/g of soil for bone meal-amended soil. Twenty-eight-day median effect concentrations (EC50s; concentration causing a reduction by 50% of a stated parameter) of Pb for weight change were 1,408 ± 198 ,g/g of soil for bone meal-free soil and 3,334 ± 731 ,g/g of soil for bone meal-amended soil and EC50s for cocoon production were 971 ± 633 ,g/g of soil for bone meal-free soil and 1,814 ± 613 ,g/g of soil for bone meal-amended soil. Significant mortalities occurred at Pb concentrations of 2,000 ,g/g of soil in the bone meal-free soil and 5,000 ,g/g of soil in the bone meal-amended soil. Earthworm Pb body load was lower in the bone meal-treated soil than in the bone meal-free soil up to a Pb concentration of 5,000 ,g/g of soil. Earthworm Pb body load was approximately 100 ,g/g of worm in surviving earthworms in both experiments when significant mortality occurred. Water and diethylenetriamine pentaacetic acid-extractable soil Pb showed good correlations with earthworm Pb body load. These extractions could be used as estimates for Pb bioavailability. [source] Acute and chronic toxicity of nitrate to fathead minnows (Pimephales promelas), ceriodaphnia dubia, and Daphnia magnaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2000George Scott Abstract Increasing concentrations of nitrate in surface water and groundwater are becoming a worldwide concern, yet little information has been published on toxicity of nitrate to common organisms used for toxicity testing. The acute and chronic toxicity of nitrate (NO3 -N) to Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas was investigated in 48-h to 17-d laboratory exposures. The 48-h median lethal concentration (LC50) of nitrate to C. dubia and D. magna neonates was 374 mg/L NO3 -N and 462 mg/L NO3 -N. The no-observed-effect concentration (NOEC) and the lowest-observed-effect concentration (LOEC) for neonate production in C. dubia were 21.3 and 42.6 mg/L NO3 -N, respectively. The NOEC and LOEC values for neonate production in D. magna were 358 and 717 mg/L NO3 -N, respectively. The 96-h LC50 for larval fathead minnows (P. promelas) was 1, 341 mg/L NO3 -N. The NOEC and LOEC for 7-d larval and 11-d embryo-larval growth tests were 358 and 717 mg/L NO3 -N, respectively. Additional exposure of breeding P. promelas and their fertilized eggs to nitrate did not increase susceptibility further. The LC50 values for all species tested were above ambient concentrations of nitrate reported for surface water. However, the LOEC for C. dubia was within the range of concentrations that could be found in streams draining areas under extensive agricultural cultivation. [source] Evaluating the impact of pollution on plant,Lepidoptera relationshipsENVIRONMETRICS, Issue 4 2005Christian Mulder Abstract We monitored the biodiversity of plants, adult butterflies and leaf-miners in a Dutch nature reserve over a period of six years (1994,1999) within the International Co-operative Programme on Integrated Monitoring on Air Pollution Effects (ICP-IM). Butterfly abundance decreased steadily over the period, indicating a negative diversity trend, while the number of leaf-mining larvae of Microlepidoptera remained fairly constant. Also the concentration of pollutants (NH4, NO3, SO4, Cd, Cu and Zn) was determined in air, leaves, litter, throughfall and stemflow. We have no reason to expect a negative impact of acidification in rainwater or climate change, as temperature and ozone show no significant trends across the six years. It is shown that the nectar-plants of adult butterflies are much more sensitive to heavy metals than the nectar-plants of moths and other pollinating insects. It is hypothesized that the butterfly decline is a secondary effect of heavy metal stress on local plants, not resulting in a decrease in the number of host-plants, but in a selective pressure of pollutants on the plant vigour, subsequently affecting their pollinators (p,<,0.001). An alternative explanation, such as the possible coexistence of a direct effect of xenobiotics on the adult Lepidoptera occurring in the study area, is not supported by our data (p,>,0.05). Copyright © 2005 John Wiley & Sons, Ltd. [source] Syntheses, Crystal Structures, and the Phase Transformation of Octacyanometallate-Based LnIII,WV Bimetallic Assemblies with Two-Dimensional Corrugated LayersEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2010Ai-Hua Yuan Abstract The reactions between Ln(NO3)3·nH2O and (Bu3NH)3[W(CN)8]·H2O have led to two series of octacyanometallate-based complexes: Ln(H2O)5[W(CN)8] [Ln = La(1), Pr(2), Nd(3), Eu(4), Gd(5)] and Ln(H2O)4[W(CN)8] [Ln = Ho(6), Er(7), Tm(8), Lu(9)]. The crystal structures of 1,9 have two-dimensional corrugated layers in which the LnIII and WV centres are linked in an alternating fashion. Thermogravimetric (TG) and powder XRD results reveal the presence of a phase transformation in the LnIII,WV system with increasing atomic number of the LnIII atoms. [source] Self-Assembled Lanthanide Salicylaldimines with a Unique Coordination ModeEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2010gorzata T. Kaczmarek Abstract New lanthanide salicylaldimine complexes of the formula [Ln(H2L)3(NO3)3](H2L), where Ln = La3+ (1), Nd3+ (2), Eu3+ (3), Gd3+ (4), Ho3+ (5), Er3+ (6), Tb3+ (7) or Yb3+ (8), and H2L = N,N,-bis(salicylidene)-4-methyl-1,3-phenylenediamine, were formed in a self-assembly process involving the lanthanide template-induced one-step [2+1] Schiff base condensation reaction between salicylaldehyde and 4-methyl-1,3-phenylenediamine. The unusual coordination pattern of salen-type ligands in these complexes, in which the three potentially tetradentate N2O2 salicylaldimines function as undeprotonated, monodentate, exclusively O-donor ligands without involving the nitrogen atoms in the coordination environment, was proved by single-crystal X-ray diffraction analysis and correlated with spectroscopic characterization. In this species with the nine-coordinate distorted tricapped trigonal prism geometry, the nitrates act as bidentate chelators occupying six coordination sites and leaving the remaining sites available for salicylaldimine ligands formed in situ in the template process. The additional salicylaldimine molecule acts as a guest for the salicylaldimine complex host and stabilizes the overall self-assembled supramolecular network. [source] Copper Complexes with Neutral N4 Tripodal Ligands: Influence of the Number of Nitrogen Donors on Their Structures, Properties, and Reactivity,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2009Kiyoshi Fujisawa Abstract Copper coordination complexes of the neutral tetradentate nitrogen-containing ligands tris(3,5-dimethylpyrazol-1-ylmethyl)amine (L0N4) and tris(3,5-diisopropylpyrazol-1-ylmethyl)amine (L1N4), namely the copper(II) chlorido complexes [CuII(L0N4)Cl2] (1) and [CuII(L1N4)Cl2] (2), the copper(II) nitrato complexes [CuII(L0N4)(NO3)](NO3) (3) and [CuII(L1N4)(NO3)](NO3) (4), and the copper(II) sulfato complexes [CuII(L0N4)(SO4)] (5) and [CuII(L1N4)(SO4)] (6), and the copper(I) complexes [CuI(L0N4)](PF6) (7) and [CuI(L0N4)(PPh3)](ClO4) (8), have been systematically synthesized in order to investigate the influence of the number of nitrogen donors on their structures, properties, and reactivity. All copper(II) complexes were fully characterized by X-ray crystallography and by IR/far-IR, UV/Vis absorption, and ESR spectroscopy. Although the structure of 7 was not determined by X-ray crystallography, this complex and the structurally characterized copper(I) triphenylphosphane complex 8 were fully characterized by IR/far-IR and NMR spectroscopy. A comparison of the copper(II) complexes with two tris(pyrazol-1-ylmethyl)amine ligands with different bulkiness of the pyrazolyl rings has allowed us to evaluate the second coordination sphere effects of the ligands. Moreover, the structures and physicochemical properties of these complexes are compared with those of related complexes containing the neutral tridentate tris(pyrazolyl)methane ligand and the neutral bidentate bis(pyrazolyl)methane ligand. Finally, the relative stability of the copper(I) complexes is discussed. The influence of the number of nitrogen donors in copper complexes is observed from these systematic results.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Bis(terdentate) Pyrazole/Pyridine Ligands: Synthesis, Crystal Structures and Magnetic Properties of Bridged Binuclear and Tetranuclear Copper(II) ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2009Akhilesh Kumar Singh Abstract A new binucleating bis(terdentate) ligand, 3,5-[3-bis(2-pyridyl)pyrazole-1-ylmethyl]pyrazole (HL2), was synthesized. Reaction of the deprotonated ligand L2 with hydrated CuII salts gives (,-pyrazolato)(,-hydroxido)-bridged binuclear and tetranuclear complexes [L2Cu2(,-OH)(ClO4)(MeCN)](ClO4) (2), [L2Cu2(dmf)2(,3 -OH)]2(ClO4)4·4dmf (3·4dmf) and [L2L,Cu2](ClO4)2 [4; HL, = 3-(2-pyridyl)pyrazole]. In these complexes, both ,-OH and ,3 -OH bridges were observed. This contrasts the situation for a dicopper(II) complex of the related bis(terdentate) ligand 3,5-bis[6(2,2,-dipyridyl)]pyrazole (HL1), {L1Cu2(OMe)(MeOH)[,1 - O -(NO3)]}{[Cu2(NO3)2(,-OMe)2]}0.5·MeOH (1·MeOH), where the shorter and more rigid ligand side arms enforce a larger Cu···Cu separation and the formation of a MeO,HOMe moiety within the bimetallic pocket. Molecular structures of all complexes were elucidated by X-ray crystallography. Variable-temperature magnetic susceptibility measurements (295,2 K) for powdered samples of complexes 2,4 reveal strong antiferromagnetic coupling between two copper centres. The magnitude of the coupling is discussed in view of the structural features. During the preparation of complex 4, partial ligand hydrolysis was also observed, but this strongly depends on the reaction conditions.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Solid-State and Solution Structure of Lanthanide(III) Complexes with a Flexible Py-N6 Macrocyclic LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2009Cristina Núñez Abstract Lanthanide complexes of a hexaaza macrocyclic ligand containing a pyridine head unit (L) were synthesized (Ln = La,Lu, except Pm). The solid-state structures of the corresponding La, Ce, Pr, Nd, and Lu complexes were determined by single-crystal X-ray crystallography, and they reveal the presence of three different mononuclear complexes with three different conformations of the macrocycle and coordination environments around the metal ions. In all complexes the lanthanide ion is coordinated in an endomacrocyclic manner to the six nitrogen donor atoms of the ligand. In the La, Ce, and Pr complexes the metal ions show a 12-coordinate mononuclear environment in which 3 nitrate anions coordinate in a bidentate fashion. However, in the Nd analogue the metal ion displays a 10-coordinated environment with the coordination of 2 bidentate nitrate groups, whereas Lu shows a 9-coordinate environment interacting with 2 nitrate ligands, one of them acting as bidentate and the second one coordinating in a monodentate fashion. The 1H and 13C NMR spectra of the complexes recorded in CD3CN suggest that the complexes adopt in solution a similar structure to that observed for the Nd complex in the solid state. The [Ln(L)(NO3)3] and [Ln(L)(NO3)2]+ complexes were characterized by density functional theory (DFT) calculations (B3LYP model). The structures obtained from these calculations for La, Ce, Pr, and Nd are in good agreement with the experimental solid-state structures. The relative stabilities of the [Ln(L)(NO3)2]+ complexes with respect to the [Ln(L)(NO3)3] ones (Ln = La, Nd, Gd, Ho, or Lu) were studied both in vacuo and in acetonitrile solution (PCM model) at the same computational level. Our calculations indicate that in solution the [Ln(L)(NO3)2]+ species is the most stable one along the whole lanthanide series, in agreement with the NMR spectroscopic data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Palladium(II) Phosphotungstate Derivatives: Synthesis and Characterization of the [Pdx{WO(H2O)}3,x{A,,-PW9O34}2](6+2x), AnionsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2009Richard Villanneau Abstract A series of PdII derivatives of the [P2W21O71(H2O)3]6, heteropolytungstate with the general formula [Pdx{WO(H2O)}3,x{A,,-PW9O34}2](6+2x), (x = 1,3) is described. These compounds are obtained by the reaction between [PdII(NO3)2]·H2O and the corresponding vacant polyoxometalates in water. They are characterized by IR and multinuclear NMR (31P and 183W) spectroscopy. Compound K10[Pd2{WO(H2O)}{A,,-PW9O34}2]·30H2O was characterized by XRD: it crystallized in the orthorhombic space group Pcmn with parameters a = 18.119(3) Å, b = 19.729(3) Å, c = 24.856(5) Å, V = 8886(3) Å3.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Controlled Assembly of [Nb6,xWxO19](8,x), (x = 0,4) Lindqvist Ions with (Amine)copper ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2008Travis M. Anderson Abstract The mixed addenda isopolyanion, [N(CH3)4]2Na2[cis -Nb2W4O19]·18H2O, reacts with Cu(NO3)2 in water and in the presence of NH2CH2CH2NH2 (en) or NH4OH at 60 °C to yield a phase that is decorated {[Cu(en)2(H2O)]2[Nb2W4O19]·2H2O (1)} or charge-balanced {[Cu(NH3)4(H2O)]2[Nb2W4O19]·8H2O (2)}, respectively, by (amine)copper complexes. The prolonged heating at 95 °C of [N(CH3)4]6[Nb10O28]·6H2O, [N(CH3)4]2Na2[cis -Nb2W4O19]·18H2O, or Na4K2[cis -Nb4W2O19]·12H2O and Cu(NO3)2 in a mixed water/amine [en or NH2CH2CH2CH2NH2 (dap)] solution results in the formation of two-dimensional materials with alternate layers of (amine)copper complexes linking Lindqvist [Nb6,xWxO19](8,x), (x = 0,4) clusters. These phasesinclude: [Cu(dap)2]3[Nb4W2O19]·7H2O (3), [Cu(dap)2]3[H2Nb6O19]·6H2O (4), [Cu(dap)2]3[Nb3W3O19]·Cl·6H2O (5), and [Cu(en)2]3[Nb4W2O19]·6H2O (6). Complexes 4 and 5 result from the decomposition of [Nb10O28]6, and [cis -Nb2W4O19]4, to [H2Nb6O19]6, and [fac -Nb3W3O19]5,, respectively, in alkaline solution. Complex 5 contains an extra-framework site that is occupied by Cl,, but this site is occupied by a water molecule in 3 and is vacant in structures 4 and 6. The results of this study suggest that charge density, cluster charge and symmetry, and cluster-cation pairing are all important parameters in the incorporation of d-electron metals onto the surfaces of [Nb6,xWxO19](8,x), (x = 0,4) clusters or into the frameworks of Lindqvist-based complex materials.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] | ||||||||||||||||||||||||||||||||||||||||||||||