Copper Uptake by Blue-Green Algae

Experiments to study the influence of biomass concentration and pH on copper uptake by blue-green algae were performed. Differential pulse anodic stripping voltammetry (DPASV) was used for copper analysis. The maximum copper uptake per unit of biomass depends only on copper concentration and not on biomass concentration. Hence the copper toxicity is independent of biomass over a wide range. A main factor influencing copper uptake is the pH. Whereas the copper uptake of Aphanizomenon gracile is rapid at pH = 8.2 we did not find a significant uptake at pH = 5.7. The copper uptake at the higher pH value is followed by a nearly complete release of this copper, accompanied by a fast shortening of trichomes. There was no significant copper uptake in Oscillatoria redekei at pH = 8.2, but at pH = 7.2 the uptake pattern of this species is similar to that of Aphanizomenon at pH = 8.2. The results suggest that the metal ion uptake mechanisms of different species have not the same pH optima.     

Study of the Interaction Mechanism in the Biosorption of Copper(II) Ions onto Posidonia oceanica and Peat

A systematic approach was used to characterize the biosorption of copper(II) onto two biosorbents, Posidonia oceanica and peat, focusing on the interaction mechanisms, the copper(II) sorption–desorption process and the thermal behavior of the biosorbents. Sorption isotherms at pH 4–6 were obtained and the experimental data were fitted to the Langmuir model with a maximum uptake (q_max) at pH 6 of 85.78 and 49.69 mg g^?1, for P. oceanica and peat, respectively. A sequential desorption (SD) with water, Ca(NO₃)₂, and EDTA was applied to copper‐saturated biosorbents. Around 65–70% copper(II) were desorbed with EDTA, indicating that this heavy metal was strongly bound. The reversibility of copper(II) sorption was obtained by desorption with HCl and SD. Fourier transform IR spectroscopy (FTIR) analysis detected the presence of peaks associated with OH groups in aromatic and aliphatic structures, CH, CH₂, and CH₃ in aliphatic structures, COO^? and COOH groups and unsaturated aromatic structures on the surface of both biosorbents, as well as peaks corresponding to Si? O groups on the surface of peat. The results of SEM‐EDX and FTIR analysis of copper‐saturated samples demonstrated that ion exchange was one of the mechanisms involved in copper(II) retention. Thermal analysis of biosorbent samples showed that copper(II) sorption–desorption processes affected the thermal stability of the biosorbents.     

Effect of Complexing Agents on the Acute Toxicity of Copper to Common Guppy Lebistes reticulatus (PETERS)

The acute toxicity of copper and copper plus complexing agents to common guppy Lebistes reticulatus was studied for 96 h by a static bioassay technique. The addition of complexing agents viz. disodium salt of EDTA, citric acid, sodium thiosulphate and glycine in Cu²⁺ solutions caused a great decrease in the per-cent mortality as compared to that of Cu²⁺ test solutions alone. 10 mg/l of complexing agent was added in each copper concentration in all the test series. The 96 h LC₅₀ values and 95% confidence limits in mg/l of Cu²⁺ plus were 1.23 (0.95…1.65) for Cu²⁺ alone; 4.30 (4.04 … 4.55) for Cu²⁺ plus EDTA; 1.94 (1.69 … 2.18) for Cu²⁺ plus citric acid; 3.44 (2.96 … 3.74) for Cu²⁺ sodium thiosulphate and 2.29 (2.22 … 3.02) for Cu²⁺ plus glycine.     

Lithological and hydrological controls on water composition: evaporite dissolution and glacial weathering in the south central Andes of Argentina (33°–34°S)

Lithological and hydrological influence on fluvial physical and chemical erosion was studied in a glacierized sedimentary basin with high evaporite presence. Suspended particulate matter (SPM), total dissolved solids (TDS) and major ion concentrations were analysed for 2 years of different hydrologic condition: (i) 2009–2010, Q = 100% average; and (ii) 2010–2011, Q = 60% average. Annual hydrograph was simple regime‐type with one peak in summer related to snow melting. The intra‐annual SPM and TDS variations were directly and inversely associated to Q, respectively. Snow chemistry showed continental influence (Na⁺/Ca²⁺ = 0.17), and atmospheric input of TDS was <1% of the total exported flux. River water was highly concentrated in Ca²⁺ and SO₄²⁻ (~4 mmol l⁻¹) and in Na⁺ and Cl⁻ (~3 mmol l⁻¹). Ca²⁺/SO₄²⁻ and Na⁺/Cl⁻ molar ratios were ~1 and related to Q, directly and inversely, respectively. Major ion relationships suggest that river chemistry is controlled by evaporite (gypsum and halite) dissolution having a summer input from sulfide oxidation and carbonate dissolution, and a winter input from subsurface flow loaded with silicate weathering products. This variation pattern resulted in nearly chemostatic behaviour for Ca⁺, Mg²⁺ and SO₄²⁻, whereas Na⁺, Cl⁻ and SiO₂ concentrations showed to be controlled by dilution/concentration processes. During the 2009–2010 hydrological year, the fluxes of water, SPM and TDS registered in the snow melting–high Q season were, respectively, 71%, 92% and 67% of the annual total, whereas for equal period in 2010–2011, 56% of water, 86% of SPM and 54% of TDS annual fluxes were registered. The SPM fluxes for 2009–2010 and 2010–2011 were 1.19 × 10⁶ and 0.79 × 10⁶ t year⁻¹, whereas TDS fluxes were 0.68 × 10⁶ and 0.55 × 10⁶ t year⁻¹, respectively. Export rates for 2009–2010 were 484 t km² year⁻¹ for SPM and 275 t km² year⁻¹ for TDS. These rates are higher than those observed in glacierized granite basins and in non‐glacierized evaporite basins, suggesting a synergistic effect of lithology and glaciers on physical and chemical erosion. Copyright © 2014 John Wiley & Sons, Ltd.     

Ökologische und physiologische Untersuchungen an der planktischen BlaualgeOscillatoria rubescens D.C. unter besonderer Berücksichtigung von Licht und Temperatur

Zusammenfassung Der Vierwaldst?ttersee (Horwer Bucht), Thunersee (H?he Faulensee), Luganersee (Bucht von Lugano) und Mauensee (ein Kleingew?sser im Schweizerischen Mitelland) wurden im Zeitabschnitt 1965 bis 1967 periodisch untersucht. Durch die chemische Analyse wurden die folgenden Komponenten erfasst: Sauerstoff, Nitrat— Stickstoff, Phosphat— Phosphor (PO₄−P), partikul?rer Phosphor (PP), SBV und pH-Wert. Das Phytoplankton wurde im umgekehrten Mikroskop ausgez?hlt, wobei der quantitativen Verteilung vonOscillatoria rubescens D. C. in den verschiedenen Tiefenstufen besondere Beachtung geschenkt wurde. Gleichzeitig wurden Temperatur und subaquatische Ver?nderungen des lichtes gemessen sowie mit der C¹⁴-Methode die Prim?rproduktion bestimmt. In mehr als 80% aller F?lle fielen dieOscillatoria rubescens-Maxima mit jenen Tiefenstufen zusammen, in denen weniger als 14°C gemessen wurde. In diesen Tiefenstufen wurde gleichzeitig in mehr als 65% aller F?lle weniger als 4% der Oberfl?chen-intensit?t des grünen Lichtes (VG 9) beobachtet. Der Einfluss von Licht und Temperatur auf das Wachstum vonOscillatoria rubescens wurde in einem Lichtthermostat experimentell untersucht. Bei temperaturabh?ngigenI _k-Werten zeigte sich, dass sich diese Alge bei einer Lichtintensit?t von 1500 Lux erst im Bereich von 30°C optimal entwickelt. Oberhalb 29°C wirkte sich eine Steigerung über 1500 Lux hinaus wieder hemmend aus. Aus diesen Beobachtungen wurde abgeleitet, dass es sich beiOscillatoria rubescens um eine eurytherme und oligophote Form handelt, und dass das Auftreten vonOscillatoria rubescens-Maxima in der vertikalen Verteilung des Phytoplanktons in einem See durch das Zusammenspiel der beiden Faktoren Licht und Temperatur bedingt wird.

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Summary The Lakes of Lucerne (Horw Bay), Thoune (Faulensee region), Lugano (Lugano Bay) and Lake Mauen, a small lake in central Switzerland, were investigated periodically from 1965 to 1967. The water was analysed in view of determining the following components: oxygen, nitrate-nitrogen, phosphate-phosphorus (PO₄−P), phosphorus incorporated in cell mass (PP), Langlier index. Phytoplankton was counted in an inverted microscope with special consideration to quantitative distribution ofOscillatoria rubescens D. C. at various depths. Temperature and light variations in function of depth were measured simultaneously and the production rate was determined by means of the C-14 method. In over 80% of all cases, theOscillatoria rubescens-maxima coincided with depths showing temperatures under 14°C. In over 65% of all cases, the intensity of green light (VG9) in such depths was less than 4% of the surface intensity. The influence of light and temperature on the growth ofOscillatoria rubescens was tested with a light thermostat. It was shown that maximum growth occurred at temperatures around 30°C and light intensities of 1500 Lux. Increase of light intensities above 1500 Lux had a negative effect on the growth rate at temperatures higher than 29°C. Our investigations lead to the conclusion thatOscillatoria rubescens is a eurythermal, oligophotic species and that the occurrence ofOscillatoria rubescens-maxima in the vertical distribution of the phytoplankton in a lake is caused by the combined effects of light and temperature.

     

Degradation Pathway of the Photochemical Oxidation of Ethylenediaminetetraacetate (EDTA) in the UV/H2O2-process

The degradation pathway for the oxidation of EDTA in the UV/H₂O₂-process was investigated. In absence of iron ions, the mineralization of EDTA is dominated by the reaction of the HO-radicals generated by the photolysis of H₂O₂. The organic degradation products iminodiacetate (IMDA), glycinate, oxamate, glyoxylate, oxalate and formate, and the inorganic degradation products carbon dioxide, ammonia, nitrate, nitrite, and cyanate were found. In the presence of iron ions, photolytic decarboxylation processes inside the complex get an important role during degradation, and the organic degradation products ethylenediaminetriacetate (ED3A), ethylenediaminediacetate (EDDA), ethylenediaminemonoacetate (EDMA) were also found. By combining product studies with balances of carbon and nitrogen, the degradation pathway in the UV/H₂O₂-process could be elucidated. The degradation of EDTA was fast (k_deg = 0.012 s^–1), and no toxic degradation products were identified. Therefore, the process is well suited for the elimination of EDTA in water treatment.     

Untersuchung der Anwendungsmöglichkeiten von einigen komplexbildenden Ionenaustauschern zur Kupferabtrennung aus natürlichen Wässern und Abwässern

Application of Some Complexing Ion Exchangers for Copper Recovery from Natural Water and Wastewater The rational use of water resources is one of the urgent environmental control problems. These problems can be solved by the treatment of sewage. Removal of different non‐ferrous heavy metal ions from wastewater is of great importance. Besides, the selective complexing ion exchangers are of interest because of their good sorption properties. The present paper is devoted to the study of some complexing resins for copper recovery from natural water and sewage. The following carboxylic resins were studied: the cation exchangers KB‐2T, KB‐4 and the amphoteric ion exchangers ANKB 35, AMF‐2T, and AMF‐2S (manufacturer – “TOKEM” company, Kemerovo, Russia). The exchangers investigated differed from each other both by their functional groups and by their matrix physical structures. The copper recovery from CuCl₂‐, CuSO₄‐, and Cu(NO₃)₂‐solutions was studied in batch‐experiments (in presence of NaCl, Na₂SO₄, and NaNO₃). The initial copper concentration in the solutions was 0.0002...0.008 mol/L; pH values were 1.0...5.0. After equilibrium (24 h) the resins were separated from the solution. The copper concentration in the solutions after the sorption was determined by the photometrical method with pyridylazoresorcin (λ = 500 nm). On the basis of the experimental data distribution ratio, the separation factors, equilibrium constants, and stability constants of copper complexes in the exchanger phase were calculated. It was found out in this work that the amphoteric ion exchanger AMF‐2T of macroreticular structure is the most effective for the copper sorption from sewage.     

Vergleichende Untersuchungen über das Phosphataufnahmevermögen ausgewählter Bakterienarten

The P-uptake by Acinetobacter calcoaceticus, Pseudomonas aeruginosa and Escherichia coli is determined in batch culture with peptone/glucose/sodium chloride or peptone/acetate/sodium chloride as substrate at 60 to 120 mg/1 orthophosphate for 20 h with cell densities of 2 · 10⁷/ml (Acinetobacter) or 1.2 · 10⁹. The measurements were carried out by means of an Na₂HPO₄ (³²P) addition of 95 to 420 kBq. During the stationary phase the bacteria achieved the following P-contents in the biomass in fg/g bacterium: Acinetobacter 6 to 13, Pseudomonas 0.2 to 0.6, Escherichia 0.04 to 0.09; during the phase of growth Acinetobacter achieved 40 to 100 fg/bacterium. Acetate as the substrate did not result in any increase of the P-uptake. The maximum accumulation with Acinetobacter was 13 % P in the dry substance.     

Petrogenetic modeling of rock variety in the Khalkhab–Neshveh pluton,NW of Saveh,Iran

The Khalkhab–Neshveh (KN) pluton is a part of Urumieh–Dokhtar Magmatic Arc and was intruded into a covering of basalt and andesite of Eocene to early Miocene age. It is a medium to high‐K, metaluminous and I‐type pluton ranging in composition from quartz monzogabbro, through quartz monzodiorite, granodiorite, and granite. The KN rocks show subtle differentiation trends strongly controlled by clinopyroxene, plagioclase, hornblende, apatite, and titanite, where most major elements (except K₂O) are negatively correlated with SiO₂; and Al₂O₃, Na₂O, Sr, Eu, and Y define curvilinear trends. Considering three processes of magmatic differentiation including mixing and/or mingling between basaltic and dacitic magmas, gravitational fractional crystallization and in situ crystallization revealed that the latter is the most likely process for the evolution of KN magma. This is supported by the occurrence of all rock types at the same level, the lack of mafic enclaves in the granitoid rocks, the curvilinear trends of Na₂O, Sr, and Eu, and the constant ratios of (⁸⁷Sr/⁸⁶Sr)_i from quartz monzodiorite to granite (0.70475 and 0.70471, respectively). In situ crystallization took place via accumulation of plagioclase and clinopyroxene phenocrysts and concentration of these phases in the quartz monzogabbro and quartz monzodiorite at the margins of the intrusion at T ≥ 1050°C, and by filter pressing and fractionation of hornblende, plagioclase, and later biotite in the granitoids at T = ～880°C.     

“Man and the Biosphere”-Studies on Sikkim Himalayas. Part 1: Acute Toxicity of Copper and Zinc to Common Carp Cyprinus carpio (Linn.) in Soft Water

In the daily exchange of the medium with only 7.1 mg/l Ca²⁺ and 0.7 mg/l Mg²⁺ during the batch experiment the LC_50,96h for Cyprinus carpio is 0.063 mg/l Cu²⁺ and 3.12 mg/l Zn²⁺ at water temperatures of 11 to 14°C. Significant differences in mortality as referred to the LC_50,12h occur for copper only after 72 h of exposure and for zinc after 48 h of exposure. The values of LC_50,96h are clearly lower for both metals in the investigations described than most data given in literature for different fish species.     

Fractionation of Ni,Cr and Cu from Soil by Sequential Extraction Procedure and Determination by Inductively Coupled Plasma Optical Emission Spectrometry

Five‐step sequential extractions were employed to fractionation of Ni, Cr and Cu in soil polluted by anthropogenic activities and determine the mobility of the metals. Twelve samples were collected on an agricultural area that was located near an airport and intercity roads in Elazig‐Turkey. Exchangeable, organically bounded, carbonate bounded, adsorbed species on Fe and Mn oxides and residual species (except silicates) of Ni, Cr and Cu were extracted into solution by using CaCl₂, Na₄P₂O₇, Na₂EDTA, NH₂OH–HCl and HNO₃–H₂O₂, respectively. Mobile metal concentrations in fractions and total recoverable in soils were determined by using inductively coupled plasma‐optical emission spectrometry (ICP‐OES). Total recoverable Ni, Cr and Cu concentrations were in the range of 40–119, 45–126 and 23–72 mg kg^?1, respectively. It was observed that total concentrations of metals in some of the samples were higher than the permitted values. The sum of the mobile percentages of metals was found to be lower than 50%. The Ni, Cr and Cu percentages for exchangeable species are in the ranges of 0.18–1.64, 0.03–0.59 and 0.42–2.53%, respectively.     

Seasonal dynamics and exports of elements from a first‐order stream to a large inland lake in Michigan

Headwater streams are critical components of drainage systems, directly connecting terrestrial and downstream aquatic ecosystems. The amount of water in a stream can alter hydrologic connectivity between the stream and surrounding landscape and is ultimately an important driver of what constituents headwater streams transport. There is a shortage of studies that explore concentration–discharge (C‐Q) relationships in headwater systems, especially forested watersheds, where the hydrological and ecological processes that control the processing and export of solutes can be directly investigated. We sought to identify the temporal dynamics and spatial patterns of stream chemistry at three points along a forested headwater stream in Northern Michigan and utilize C‐Q relationships to explore transport dynamics and potential sources of solutes in the stream. Along the stream, surface flow was seasonal in the main stem, and perennial flow was spatially discontinuous for all but the lowest reaches. Spring snowmelt was the dominant hydrological event in the year with peak flows an order of magnitude larger at the mouth and upper reaches than annual mean discharge. All three C‐Q shapes (positive, negative, and flat) were observed at all locations along the stream, with a higher proportion of the analytes showing significant relationships at the mouth than at the mid or upper flumes. At the mouth, positive (flushing) C‐Q shapes were observed for dissolved organic carbon and total suspended solids, whereas negative (dilution) C‐Q shapes were observed for most cations (Na⁺, Mg²⁺, Ca²⁺) and biologically cycled anions (NO₃^?, PO₄^3?, SO₄^2?). Most analytes displayed significant C‐Q relationships at the mouth, indicating that discharge is a significant driving factor controlling stream chemistry. However, the importance of discharge appeared to decrease moving upstream to the headwaters where more localized or temporally dynamic factors may become more important controls on stream solute patterns.     

Eliminierung von Schwermetallen aus komplexbildnerhaltigen Abwässern durch Kalk-/Kreide-Fällung

A report is given on laboratory investigations into model waters containing Cu²⁺-, Ni²⁺- or Zn²⁺-ions and tartrate, citrate, NTA or EDTA as complexing agents. There were determined residual concentrations of the metal ions at different shares of complexing agents, which are achieved by the precipitation with lime and chalk. Chalk is added in order to secure the required exess of calcium ions without causing an overalkalinization of the water. In the range of pH = 8…9, however, residual concentrations lower than 1 mg/1 are achieved only for copper ions in the presence of tartrate.     

Festkontaktierte potentiometrische Elektroden für Sulfatbestimmungen in wässrigen Lösungen

Solid‐contacted Potentiometric Electrodes for Measurements of Sulfate Ions in Aqueous Solutions A solid‐contact electrode for potentiometric measurement of sulfate ions in aqueous solutions was developed and examined. The electrode is based on a PVC membrane which contains the ionophore 3‐decyl‐1,5,8‐triazacyclodecan‐2,4‐dione (DTADD). Instead of the usual inner fluid junction, a polypyrrole layer applied on the inner side of the PVC membrane was employed as inner solid contact. The performance of this electrode was compared to solid‐state sulfate‐selective electrodes with the ionophore α,α′‐bis(N′‐phenylthioureylene)‐m‐xylene (BTH) and to electrodes in the coated‐wire configuration. For the parameters sensitivity, selectivity, and long‐term stability, electrodes with the DTADD ionophore show improved properties. In the sulfate concentration range of 5·10^–5...10^–2 mol L^–1 the slope of the response is –(26.8 ± 0.5) mV/decade. The new solid contact sulfate electrodes showed a very low drift of the electrode potential within a period of 150 days when the electrode was stored in 10^–2 M Na₂SO₄. In Na2SO4 solutions of the pH range of 4...9 the electrode potentials were constant. The 95% response time was about 10 s when the sulfate concentration was changed from 10^–4 mol L^–1 to 10^–3 mol L^–1. The selectivity with DTADD ionophore relating to the nitrate ions is higher than the selectivity with BTH. Improvements are also made in comparison with sulfate‐selective electrodes described in the literature which contain other ionophores with fluid inner reference electrolytes.     

The effect of light on the release of organic compounds by the cyanobacteriumOscillatoria rubescens

The effect of light intensity on the release of dissolved organic carbon during photosynthesis on NaH¹⁴CO₃ was investigated using the phytoplanktonic CyanobacteriumOscillatoria rubescens. The released products were fractionated by molecular size and chemical identifications attempted using combined thin-layer electrophoresis and chromatography, and high pressure liquid chromatography.Within the range of irradiances tested (from 6 to 60 µmole m^–2 sec^–1), though the upper one inhibited photosynthesis ofO. rubescens, light had little effect on the quantity and composition of the excreted products. The released carbon was always lower than 3% of the incorporated carbon, and mainly composed (62 to 86%) by small molecular weight compounds. The prevailing identified compounds were amino acids which represented more than 20% of the excreted carbon. Among organic acids, glycolic acid accounted for less than 2% of the recovered radioactivity. Glucose was the only identified sugar.Abbreviations EOC excreted organic carbon - DOC dissolved organic carbon - PER percent extracellular release - LMW low molecular weight - HMW high molecular weight - AA amino acids - µmoles m^–2 sec^–1 = µEinsteins m^–2 sec^–1     

“Man and Biosphere” — Studies on Sikkim Himalayas. Part 2: Acute Toxity of Mixed Copper-Zinc Solutions on Common Carp,Cyprinus carpio (LINN.)

In batch experiments for 6 to 48 h, individuals of Cyprinus carpio (2 g individual weight) were exposed to mixed solutions of copper and zinc sulphate: pH = 6.3, temperature 15 °C, 6.8 mg/l O₂, 7.1 mg/l Ca²⁺, 0.7 mg/l Mg²⁺. The LC₅₀ for the individual substances on exposures of 24 and 48 h amount to 9.04 and 7.28 mg/l, resp., of Zn and 0.11 and 0.095 mg/l, resp., of Cu. The sum of the biological activity of the two kinds of metal ions is assessed according to MARKING'S index: at low concentrations of the mixed solutions the two metals show an additive effect, at higher concentrations a synergistic effect occurs.     

Interface Treatment of Petroleum Hydrocarbon‐impacted Lower Permeability Layers by Activated Sodium Persulfate to Reduce Emissions to Groundwater

Nonaqueous phase liquid (NAPL)‐impacted lower permeability layers in heterogeneous media are difficult to fully remediate and can act as persistent sources of groundwater contamination through diffusive emissions to transmissive aquifer zones. This work investigated the benefits of partial remediation involving treatment focused near the high‐low permeability interface, with the performance metric being emissions reduction. A sequential base‐activated persulfate (S₂O₈ ^2?) delivery treatment strategy was studied in this work, involving 13–14 d deliveries of 10% w/w sodium persulfate (Na₂S₂O₈) and 14–28 d deliveries of 19 g/L sodium hydroxide (NaOH). Treatment and control experiments were conducted in 1.2‐m wide × 1.2‐m tall × 5‐cm thick physical model tanks containing two soil layers differing in hydraulic conductivity by three orders of magnitude. The top 10 cm of the lower permeability layers contained 7400–7800 mg‐NAPL/kg‐soil; the NAPL was comprised of benzene, toluene, ethylbenzene, p‐xylene, o‐xylene, n‐propylbenzene, and 1,3,5‐trimethylbenzene (TMB) mixed in octane. Approximately 0.1 g‐Na₂S₂O₈ was delivered per cm²‐interface area over 13–14 d. The S₂O₈ ^2? and SO₄ ^2? concentration profiles suggest higher oxidant reaction rates when NaOH is delivered prior to, rather than after Na₂S₂O₈. After 264 d and two treatments, hydrocarbon emissions from the NAPL source were reduced by 60% to 73% compared to a no‐treatment control tank. The incremental benefit of the second treatment was only about 10% of the effect of the first treatment.     

Geochemistry, K–Ar geochronology and Sr–Nd–Pb isotope compositions of pitchstone in Gohado, southwestern Okcheon Belt, South Korea

Abstract Geochemical and Sr–Nd–Pb isotope characteristics, as well as K–Ar geochronology of a massive pitchstone (volcanic glass) stock erupted into Late Cretaceous lapilli tuff and rhyolite in the Gohado area, southwestern Okcheon Belt, South Korea, are reported. The pitchstones are highly evolved with SiO₂ contents ranging from ～72 to 73 wt%, K₂O/Na₂O ratios of 1.04–1.23 and low MgO/FeO^t values (0.17–0.20). The pitchstones are weakly peraluminous and the ASI (molar Al₂O₃/Na₂O + K₂O + CaO) values are significantly lower than 1.1. The pitchstones also display a general calc‐alkaline nature with significant alkali contents. The rare earth elements (REE) compositions show moderately fractionated nature with (La/Yb)_N ranging from 11 to 16. Chondrite normalized REE patterns show relative enrichment of light REE over heavy REE and moderate Eu anomaly (Eu/Eu* ratio varies from 0.53 to 0.57). A distinct negative Nb anomaly is observed for all pitchstones on a primitive mantle normalized trace element diagram, typical of subduction‐related magmatism and crustal‐derived granites. All these features are characteristic of I‐type granites derived from a continental arc. The pitchstones have Zr contents of 98.5–103.5 ppm with zircon thermometry yielding temperatures of 749–755°C (mean 752°C). The K–Ar analyses of representative pitchstone samples yielded ages of 58.7 ± 2.3 and 62.4 ± 2.1 Ma with a mean age of 61 Ma. The rocks show nearly uniform initial ⁸⁷Sr/⁸⁶Sr isotopic ratios of 0.7104–0.7106 and identical ¹⁴³Nd/¹⁴⁴Nd initial ratio of 0.5120. The rocks display negative εNd (61 Ma) values of ?12. The depleted mantle model ages (T_DM) range from 1.54 Ga to 1.57 Ga. The Pb isotope ratios are ²⁰⁶Pb/²⁰⁴Pb = 18.522–18.552, ²⁰⁷Pb/²⁰⁴Pb = 15.642–15.680 and ²⁰⁸Pb/²⁰⁴Pb = 38.794–38.923. These ratios suggest that the Gohado pitchstones were formed in a continental arc environment by partial melting of a 1.54 Ga to 1.57 Ga parental sources of lower crustal rocks probably of mafic or intermediate compositions.     

The solubility mechanisms of volatiles in silicate melts and their relations to crystal-andesite liquid equilibria

The anionic structure of magmatic liquids has been estimated at 1 atm and at pressures corresponding to those of the upper mantle. These estimates are based predominantly on spectroscopic data on binary metal oxide-silica and ternary metal oxide-silica-alumina melts. Structural information on melt compositions in aluminate-silica joins has been used to provide detailed information on the role of Al³⁺ in natural magma at atmospheric and high pressure.Regardless of pressure, andesitic melts may be described as combinations of chain, sheet, and three-dimensional network units. Nearly all Al³⁺ in the magmatic liquid resides in the three-dimensional network units. This Al³⁺ is locally charge-balanced with Na⁺, K⁺, Ca²⁺, and Mg²⁺. In the latter two cases, Al³⁺ and Si⁴⁺ are ordered, whereas for Na⁺ and K⁺, Si⁴⁺ and Al³⁺ are randomly mixed. Solution of water in natural magma results in the formation of new nonbridging oxygens in addition to OH groups attached to Si⁴⁺ and metal cations.On the basis of determined solution mechanisms of CO₂ and H₂O in silicate melts, thermodynamic properties of HO+CO₂, fluids and hydrous silicate melts and melting phase relations in peridotite-H₂O-CO₂, systems, it is found that natural andesitic magma in equilibrium with spinel Iherzolite in the upper mantle (10–20 kbar) must contain at least 5–7 wt.% H₂O. Andesitic magma with 5–7 wt.% H₂O in solution may be described as a mixture of Al-free three-dimensional units, sheets, and chains with a small proportion (less than 10%) of monomers.     

Oxysulfates of copper, sodium, and potassium in the lava flows of the 2012–2013 Tolbachik Fissure Eruption

Samples from the surface of lava flows discharged by the 2012–2013 Tolbachik Fissure Eruption were found to contain oxysulfates of copper, sodium, and potassium: K₂Cu₃O(SO₄)₂ (fedotovite), NaKCu₂O(SO₄)₂, and Na₃K₅Cu₈O₄(SO₄)₈. The last two phases have no naturally occurring or synthetic analogues that we are aware of. They form flattened crystals of prismatic to long-prismatic habits. The crystals of Na₃K₅Cu₈O₄(SO₄)₈ have a chemical composition corresponding to the empirical formula Na_2.22K_5.47Cu_8.02S_8.05O₃₆. An X-ray analysis of this compound showed that it has a monoclinic symmetry, P2/c, a = 13.909(4), b = 4.977(1), c = 23.525(6) Å, β = 90.021(5)°, V = 1628.3(7) ų. The crystal structure was determined by direct techniques and refined to yield R ₁ for 3955 reflexes//web// with F ² > 4σF. The compound NaKCu₂O(SO₄)₂ also belongs to the monoclinic system, P2/c, a = 14.111(4), b = 4.946(1), c = 23.673(6) Å, β = 92.052(6)°, V = 1651.1(8) ų. The structure was determined by direct techniques to yield a tentative structural model that has been refined up to R ₁ = 0.135 for 4088 reflexes with F ² > 4σF. The crystal structure of Na₃K₅Cu₈O₄(SO₄)₈ is based on chains of [O₂Cu₄]⁴⁺ consisting of rib-coupled oxy-centered tetrahedrons of (OCu₄)⁶⁺. The chains are surrounded by sulfate radicals, resulting in columns of {[O₂Cu₄](SO₄)₄}^4? aligned along the b axis. The interchain space contains completely ordered positions of Na⁺ and K⁺ cations. The principle underlying the connection of NaKCu₂O(SO₄)₂ columns in the crystal structure of {[O₂Cu₄](SO₄)₄}^4? is different, in view of the relation Na:K = 1 as contrasted with 3:5 for the compound Na₃K₅Cu₈O₄(SO₄)₈. The presence of oxy-centered tetrahedrons in the structure of these new compounds furnishes an indirect hint at the importance of polynuclear copper-oxygen radicals with centering oxygen atoms as forms of transport of copper by volcanic gases.