Occurrence Of Zinc Research Articles

Stratiform base-metal deposits in the Eastern province of the Southern Urals, Russia

The stratiform base-metal Biksizak and Amur deposits, Kolpakovsky and Andree-Yul’evsky group of ore occurrences localized in the Eastern province of the Southern Urals and the adjacent Central Urals are considered in this paper. Their geology, composition of ore, and orebody morphology are characterized. These objects and occurrences occupy different geological positions, being hosted in (1) Ordovician, Silurian, and Devonian limestones formed in an island-arc setting (Biksizak deposit, Kolpakovsky occurrence); (2) Middle and Upper Devonian flyschoid sequences at a distance from the active volcanic zone (Amur deposit); and (3) Riphean (?) platform cover (Andree-Yul’evsky group of occurrences). The objects considered differ in origin. The hydrothermal Pb-Zn ores of the Biksizak deposit and the Kolpakovsky occurrence are epigenetic with respect to the host rocks. They were formed in the Early Carboniferous and related to early collisional minor andesite and quartz diorite porphyry intrusions. The hydrothermal-sedimentary Amur massive sulfide Zn deposit of the Filizchai type was formed at the end of Middle Devonian. Zinc occurrences of the Andree-Yul’evsky group are probably products of regeneration of older stratiform lodes.

Occurrence of Zinc and Lead in Aerosols and Deposits in the Fluidized-Bed Combustion of Recovered Waste Wood. Part 2: Thermodynamic Considerations

In the present work, which is the second part in a series of two, multi-phase, multi-component equilibrium calculations were used to study the chemistry and deposition behavior of lead and zinc in the combustion of recovered waste wood (RWW). Particular attention was paid to the deposition behavior in different parts of the boiler under varying flue gas and material temperature conditions. In addition, the influence of fuel composition was considered by studying three different fuel compositions. The results from the calculations were compared to experimental results from two measurement campaigns, whose goal was to experimentally determine the distribution and speciation of zinc and lead compounds in aerosol particles and deposits in the fluidized-bed combustion of RWW. The results from the experimental work are presented in part 1 (10.1021/ef101478n) of this work.

Occurrence of Zinc and Lead in Aerosols and Deposits in the Fluidized-Bed Combustion of Recovered Waste Wood. Part 1: Samples from Boilers

Combustion of recovered waste wood (RWW) has led to increased fouling and corrosion of furnace walls, superheaters, and economizers. These problems have been associated mainly with chlorine, zinc, and lead in the deposits but also with sodium and titanium. The presence of lead and zinc compounds, especially lead and zinc chlorides, has been shown to increase the corrosivity of the deposits even at relatively low metal temperatures (230−450 °C). The present work determined experimentally the distribution and speciation of zinc and lead compounds in aerosol particles and deposits in the fluidized-bed combustion of RWW. Measurements were conducted in both a full-scale (20 MWth) plant with as-received RWW and in a pilot-scale (2 MWth) setup with as-received RWW and RWW doped with zinc and lead. The results show that the amount and speciation of zinc and lead in the deposits vary depending upon the fuel composition, flue gas temperature, and metal temperature. Both lead and zinc chlorides are found in temperat...

Zinc resistance of Staphylococcus aureus of animal origin is strongly associated with methicillin resistance

This study was conducted to determine the occurrence of zinc and copper resistances in methicillin-resistant Staphylococcus aureus (MRSA) from swine and veal calves in a global strain collection.The test population consisted of 476 porcine MRSA isolates from ten European countries, 18 porcine MRSA isolates from Canada and seven MRSA from China, 92 MRSA and 60 methicillin-susceptible S. aureus (MSSA) isolates from veal calves in the Netherlands and 88 porcine MSSA isolates from four European countries. Most porcine MRSA (n=454) and all bovine MRSA belonged to clonal complex (CC) 398 whereas 37 of the pig MRSA from Europe and the seven Chinese isolates belonged to other CCs and 3 isolates were not classified into a CC.All isolates were tested for susceptibility to zinc chloride and copper sulphate using agar dilution and tested by PCR for the czrC gene encoding zinc resistance.Phenotypic zinc resistance (MIC>2mM) was observed in 74% (n=324) and 42% (n=39) of European MRSA CC398 from pigs and veal calves, respectively, and in 44% of the Canadian isolates (n=8), but not among the Chinese isolates. Almost all (99%) zinc-resistant MRSA carried czrC. Of the 37 European non-CC398 MRSA, 62% were resistant to zinc, but only 46% of them carried czrC. The MICs of the MSSA isolates to zinc chloride ranged from 1 to 4mM and none carried czrC. The MICs of copper sulphate were associated neither with methicillin resistance nor with the detection of czrC.This study showed that zinc resistance and the czrC gene are widespread among CC398 MRSA isolates. This suggests that the use of zinc in feed might have contributed to the emergence of MRSA.

Micronutrient Soil-Test Levels and Eucalyptus Foliar Contents

Eucalyptus is the most widely planted forest species in Brazil (∼3.4 million hectares). Ongoing rotations and high yields lead to the occurrence of copper (Cu), manganese (Mn), iron (Fe), and zinc (Zn) deficiency symptoms. The objectives of this work were to identify the most appropriate extractant for evaluating micronutrient availability in commercial Eucalyptus plantations and to evaluate the influence of soil properties on Eucalyptus foliar micronutrient contents. Soil micronutrient contents were extracted by Mehlich 1, Mehlich 3, and diethylenetriaminepentaacetic acid (DTPA). Mehlich 1 and Mehlich 3 extracted the greatest amounts for all micronutrients analyzed. Foliar Cu, Mn, and Zn contents showed significant and positive relationships with soil Cu, Mn, and Zn contents extracted by the three solutions. Soil organic carbon (SOC), soil clay content, and soil pH improved significantly the power of regression models in estimating foliar micronutrient contents. The improvement was greater for Mehlich 3 and DTPA extractants than for Mehlich 1.

A predictive GIS model for potential mapping of copper, lead, and zinc in Langping area, China

Mineral resource potential mapping is a complex analytical process, which requires the consideration and the integration of a number of spatial evidences like geological, geomorphological, and wall rock alteration. The aim of this paper is to establish mineral exploration model for copper, lead, and zinc in Lanping basin area using the capability of analytical tools of Geographic Information System (GIS) and remote sensing data to generate maps showing favorable mineralized area. The geo-exploration dataset used for the research includes copper, lead, and zinc deposits, geological maps, topographic maps, structural maps, and ETM+ imagery. Geological features indicative of potential copper, lead, and zinc were extracted from the datasets input in the predictive model. The method of weights of evidence modeling is a probability-based technique for generating mineral potential maps using the spatial distribution of indicative features with respect to the known mineral occurrences. The method of weights of evidence probabilistic modeling provides a quantitative method for delineating areas with potential of copper, lead, and zinc mineral deposits in the Lanping Basin area. weights (W+, W−) and contrast (C=(W+)-(W−)) calculations guide the data-driven modeling. The four most important spatial features for exploration guide for copper, lead, and zinc mineralization hosted in the Lanping Basin area are alteration zones, faults, host rocks, and lineaments. The host rocks and deep faults have the strongest spatial association with the known copper, lead, and zinc deposits. The hydrothermal alteration zones have the moderate spatial association with the copper, lead, and zinc deposits. The predicted high-favorability zones do not show the strong affinity with lineaments. The distribution of 22 (copper, lead, and zinc) occurrences in the Lanping Basin was examined in terms of spatial association with various geological phenomena. The analysis of these relationships using GIS and weights of evidence modeling has predicted areas of high and moderate mineral potential, where a little or no mining activities exist.

The Occurrence and Incorporation of Copper and Zinc in Hair and their Potential Role as Bioindicators: A Review

This article reviews evidence that suggests Cu and Zn concentrations are not altered significantly by exogenous processes and may be useful in applications of hair analysis. The review attempts to identify what Cu and Zn concentrations may actually indicate biogenically and investigates the mechanisms by which they are incorporated into hair. Associations with specific hair components are proposed and avenues for development as a bioindicator are identified. Areas of research that offer promise in application or confirming the use of Cu and Zn are also indicated. Correlations and relationships with other health disorders are reviewed. Endogenous blood concentrations may also explain alterations in hair structure relating to breast cancer.

Insect mandibles—comparative mechanical properties and links with metal incorporation

A number of arthropod taxa contain metals in their mandibles (jaws), such as zinc, manganese, iron, and calcium. The occurrence of zinc and its co-located halogen chlorine have been studied in relation to the mechanical properties and shown to be linked in a direct fashion with increasing concentration. Hardness along with elastic modulus (stiffness) has also been linked to zinc and halogen concentration in some marine polychaete worms. The metal appears to be incorporated within the biological matrix, possibly bonding with proteins. However, the comparative advantage of metal inclusion has not been tested. It is possible that without metals, alternative mechanisms are used to achieve hardness of equal value in similar 'tools' such as mandibles. This question has direct bearing on the significance of metal hardening. In the present article, we compare across mandibles from six termite species, including samples with major zinc concentration, minor manganese, and no metals. Nanoindentation, electron microscopy, and electron microanalysis are used to assess metal concentration, form, and mechanical properties. The data demonstrate that termite mandibles lacking metals when fully developed have lower values for hardness and elastic modulus. Zinc is linked to a relative 20% increase in hardness when compared with mandibles devoid of metals. The similar transition metal, manganese, found in minor concentrations, is not linked to any significant increase in these mechanical properties. This raises the question of the function of manganese, which is as commonly found in insect mandibles as zinc and often located in the same mandibles.

Occurrence and fate of corrosion-induced zinc in runoff water from external structures

This paper comprises data from an extensive cross-disciplinary research project aiming to elucidate the environmental fate of corrosion-induced zinc release from external structures. It includes an exposure assessment that provide long-term runoff rates, concentrations and chemical speciation of zinc, from 14 zinc-based materials exposed during 5 years in Stockholm, Sweden, and an effect assessment including bioavailability and ecotoxicity measurements, both at the immediate release situation and after soil interaction. Runoff rates of total zinc ranged from 0.07 to 2.5 g Zn m − 2 yr − 1 with zinc primarily released as the free ion for all materials investigated. The average effect concentration, causing a 50% growth reduction after 72 h to the green algae Raphidocelis subcapitata, was at the immediate release situation 69 μg Zn L − 1 . Upon interaction of runoff water with soil, which simulated 18 to 34 years of exposure, the total zinc concentration was significantly reduced, from milligram per litre to microgram per litre levels. Simultaneously, the most bioavailable fraction of zinc in runoff, the hydrated zinc(II)-ion, decreased from more than 95% to about 30%. The major fraction, 98–99%, of the introduced total zinc concentration in the runoff water was retained within the soil. As long as the soil retention capacity was not reached, this resulted in zinc concentrations in the percolate water transported through the soil layer, close to background values and below growth inhibition concentrations for the green algae investigated. Zinc retained in soil was to a large extent (85–99.9%) extractable with EDTA, and available for plant uptake after 5 to 7 months of ageing.

Closing the Loop on Cadmium - An Assessment of the Material Cycle of Cadmium in the U.S. (11 pp)

Goal, Scope and Background In this study, the major flows of cadmium in the U.S. economy are quantified and the primary sinks are identified to gauge the need for additional policy to minimize the potential human health and ecosystem risks associated with these flows. Because of the concurrent occurrence of cadmium and zinc in ore, we also consider the relevant portions of the material cycle of zinc.

Mineral occurrences in central East and North-East Greenland—new possibilities?

The geological provinces of central East and northeast Greenland host numerous mineral occurrences. Pre-Caledonian mineralization is scarce and its structural affiliation is not always clear. Mineral occurrences related to Caledonian lineaments comprise ores of tungsten, arsenic and antimony. Mineral occurrences related to post-Caledonian lineaments take the form of vein-type mineralization, which is widespread along the eastern fault zone, and occurrences of lead, zinc, copper and silver that are known along the lineament from Jameson Land, Traill Ø, Gauss Halvø and Hudson Land. Three major types of mineralization are related to the post-Caledonian evolution of East Greenland: (1) epigenetic, mainly base-metal mineralization occurring over a north-south extension of several hundred kilometres; (2) strata-bound-stratiform base-metal mineralization associated with red beds and carbonates; and (3) molybdenum and base-metal mineralization related to Tertiary felsic, subvolcanic intrusions. Skarn formation is found in connection with Tertiary mafic sill intrusions.When the huge area of central and North-East Greenland is taken into consideration exploration activity has been sparingly funded and sporadic by comparison with other explored areas. The post-Caledonian area of East and North-East Greenland is a crustal extension regime with good potential for mineral deposit formation. Further exploration should be focused on the investigation of extension faults, wrench faults and zones of dilatation. These fluid pathways create alteration, which must be carefully studied to improve understanding of the mineralizing system.

Iron control in zinc pressure leach processes

The occurrence of zinc in sulfide ore deposits is generally accompanied by various iron minerals. Hence, even the most efficient concentrators generally produce a zinc concentrate with significant iron content. The efficient recovery of zinc metal from zinc concentrates requires the rejection of iron residue in a form that minimizes the zinc entrainment. Careful control of the iron precipitation step is important, so that the iron residue produced is amenable to efficient liquid-solid separation in order to obtain high zinc recoveries. In hydrometallurgical zinc processes, the coprecipitation of minor impurities along with iron precipitation is also important in producing zinc-sulfate solution from which high-purity zinc cathode can be electrowon. The integration of Dynatec’s zinc pressure leach process with existing roast-leach-electrowin plants employing various methods of iron rejection is briefly described in this article, along with the application of two-stage pressure leaching in stand-alone processes.

Native copper and α-copper–zinc in sediments from the TAG hydrothermal field (Mid-Atlantic Ridge, 26°N): nature and origin

Native copper and α-copper–zinc occur as strands and elongated grains (up to 300 μm in length) within the sediments from the Trans-Atlantic Geotraverse (TAG) hydrothermal field (Mid-Atlantic Ridge, 26°N). They are remarkably similar in composition and crystal structure to copper and copper–zinc occurrences found in other natural environments. The results of mineralogical studies are discussed in terms of the possible mechanisms of native metal formation in the complex TAG field: with an asymmetric and highly-fractured rift valley, and mature active and relict sulfide mounds. Native copper and α-copper–zinc grains disseminated in the TAG sediments are either inherited from: (1) primary magmatic or metamorphic crustal source; (2) hydrothermal deposits; and (3) the alteration of primary deposits, or formed (1) authigenically, or (2) biogenically within/on the sediment cover. Native metallic particles could have been formed as accessory minerals disseminated in the ridge crest basic rocks and/or massive sulfide mounds. Degradation of these rocks and mass wasting of the mounds have liberated the metallic grains which have, in turn, been deposited into adjacent sediments.

Enzymatic properties of Escherichia coli peptide deformylase

Since its discovery in crude extracts in the late sixties, Escherichia coli peptide deformylase activity could not be further characterized because of an apparent extreme instability. We show that this behavior was caused by an inadequate activity assay, involving substrate concentration inhibition and substrate precipitation in crude extracts. The homogeneous protein, as it was previously purified (T. Meinnel and S. Blanquet J. Bacteriol. 175:7737-7740, 1993), had actually retained its initial activity. The influence on the deformylation reaction of several factors was studied and used to improve the activity assay. Pure peptide deformylase proves to act only on peptide substrates with an N-formylmethionyl moiety. In agreement with the occurrence of zinc in the enzyme, peptide deformylase activity is inhibited by 1,10-phenanthroline.

Demonstration of superoxide dismutase enzymes in extracts of pollen and anther ofzea maysand in two related products, baxtin® and polbax®

Abstract Superoxid dismutase enzymes were isolated and identified in an aqueous extract of pollen and anthers of Zea mays and in two commercial products, Baxtin® and Polbax®, derived from the same kind of source material. Prior to analysis the samples were purified by adding soluble poly-Nvinylpyrrolidon and precipitated with ammonium sulphate, Gel filtration chromatography using a Superose 12 HR column gave well-resolved and similar elution patterns for the maize extract, Baxtin and Polbax samples. Fractions exhibiting superoxide dismutase activity, determined by direct KO2 assay, were combined, dialysed and evaporated to dryness. The molecular weight of these fractions was approximately 30000 d. These fractions were also analysed by native polyacrylamide gel electrophoresis and stained for superoxide dismutase enzyme activity using nitro blue tetrazolium. The major region of superoxide dismutase enzyme activity was inhibited by addition of cyanide and hydrogen peroxide indicating the presence of a copper, zinc superoxide dismutase. Another minor region of enzyme activity, migrating as standard manganese superoxide dismutase and not inhibited by cyanide or hydrogen peroxide, was also detected. The results clearly demonstrated the occurrence of both copper, zinc- and manganese superoxide dismutase enzymes in extracts of pollen and anthers of Zea mays and also in the two related commercial products, Baxtin and Polbax.

The occurrence of zinc in Antarctic ancient ice and recent snow

Concentrations of zinc (Zn) have been measured in various sections of the Dome C and Vostok deep Antarctic ice cores, whose ages range from 3850 to 155,000 years BP, and in several large-size surface Antarctic snow blocks collected in Adelie Land and at the geographic South Pole. All the samples were mechanically decontaminated, and detailed outside-inside variation profiles were drawn for most of them then allowing us to clearly establish the accuracy of the data obtained from the analysis of the most central parts of each individual core section or snow block. Natural Zn concentrations are found to have strongly varied in Antarctic ice during the past 155,000 years, the highest values (up to about 100 pg Zn/g) being observed during the Last Glacial Maximum and possibly during the end of the next to last ice age. Wind-blown dust from crustal rock and soil appears to be the main natural source of Zn during the glacial periods, especially the Last Glacial Maximum. Zn concentrations in present-day Antarctic snow from central East Antarctica, about 5 pg Zn/g, are found to be comparable with those in Holocene ice several thousand years old, which evidences that the Antarctic tropospheric cell is still little affected by anthropogenic Zn.

Trace elements in soils and pasture herbage on farms with bovine hypocupraemia

SummaryThe importance of molybdenum, sulphur, iron, zinc and cadmium dietary antagonists to ruminant copper metabolism was investigated at the farm level in an attempt to explain the widespread occurrence of bovine hypocupraemia in recent years.From 22 of the most severely hypocupraemic regions of England, six areas with as wide a range of geological, pedological and topological situations as possible were selected for detailed field work. This involved the collection of topsoil and herbage samples from approximately 15 farms per area with hypocupraemic stock. Possible causal factors of bovine hypocupraemia were then considered on the basis of three criteria: critical concentrations of copper, molybdenum, sulphur, iron, zinc and cadmium in pasture herbage; Cu:Mo ratios in herbage; and copper availability predictions for ruminants.Absolute copper deficiency and molybdenum-induced bovine hypocupraemia were clearly demonstrated at the farm level. The results also confirmed that dietary sulphur, in particular, plays a significant yet previously unrecognized role in the widespread incidence of bovine hypocupraemia in industrialized Britain. Antagonism due to iron orginating from soil-contaminated herbage was evident, but not common. No evidence was found to support the occurrence of zinc- or cadmium-induced hypocupraemia in the areas examined.

Occurrence of manganese, copper and zinc in myelin. Alterations in the peripheral nervous system of dysmyelinating trembler mutant are at variance with brain mutants (quaking and shiverer)

Mn, Cu and Zn were present in mouse brain at concentrations that were 54, 4 and 14 times higher than in serum. In comparison with control animals, Mn was nearly normal in both quaking and shiverer dysmyelinating mutants. Cu was slightly higher in shiverer; Zn was higher in quaking only when expressed on a dry weight basis. The peripheral nervous system contained lower amounts of Mn, Cu and Zn than brain, (1 6 , 1 8 and 1 2 respectively). All three metals were much higher in trembler (4, 3 and 2-fold increase, respectively). Although higher in shiverer and quaking, Mn did not differ significantly from control. Cu and Zn were similar to control in the sciatic nerve of quaking and shiverer. Brain myelin contained Mn, Cu and Zn concentrations that were slightly smaller than those found in the whole brain. Mn and Cu were higher in the myelin from shiverer by approx. 2- and 3-times, whereas Zn was two-fold reduced. It is speculated that such metals play a role in membrane as cofactors of enzymes, especially those in control of free radical damage, and possibly also in membrane structures as phospholipid counterions.

Occurrence and Chemistry of Zinc in Freshwaters – its Toxicity and Bioaccumulation with Respect to Algae: A Review Part 2: Toxicity and Bioaccumulation with Respect to Algae

AbstractZinc has definitely been established to be required for the growth of both higher plants and algae, but it can act either in a stimulatory mode or in an inhibitory one, depending on its level of availability. A variety of environmental factors are known to modify the toxicity of zinc in water on algae. It has been observed that algae differ in their tolerance to zinc.It is well known that algae can accumulate zinc or other metals from water, producing an internal concentration greater than in their surroundings. The modes of accumulation and concentration factors are given.

The occurrence of copper, iron, zinc and other elements and the nature of some copper and iron complexes in humic substances from municipal refuse disposed of in a landfill

Municipal refuse was allowed to decompose in a simulated landfill for 20 months. Three different models were studied in which the refuse, in 40 m 3 lots, was either compacted or mixed 2:1 with sewage sludge, the latter being studied in both uncompacted and compacted states. At 2, 6, 12 and 20 months, humic substances were extracted from samples with 0.1 M Na 2P 4O 7 and 0.1 M NaOH, and humic acids isolated by precipitation after acidification with HCl. The humic substances were examined by electron paramagnetic resonance (EPR) to determine the free radical content and the nature of some of the metal complexes present. The principal form of copper was present in either a square planar or a tetragonally-distorted octahedral environment, probably coordinated to two nitrogen and two oxygen atoms. Fe 3+ was present in at least three different environments. In one, it was probably in a complex with rhombic symmetry; another showed Fe 3+ in an axially-symmetric environment, most likely as a ferric porphyrin. No distinctions could be made between the concentrations or forms of metals present in the refuse humic substances as a result of adding sewage sludge, but the additions increased the yield of humic substances, particularly in the uncompacted landfill. Humic substances in the refuse retain metal elements in complexed forms which will restrict their release from the landfill.