Analysis and Evaluation of Bioavailable Heavy Metals in Surface Soil of the Abandoned Lead-zinc Mine in Changhua,Hainan Province

[Objectives] The research was conducted to study characteristics of bioavailable levels pollution of heavy metals in the surface soil of the lead-zinc mine in Changhua.[Methods] A total of 56 surface samples were collected from the 3 study zones （peripheral zone, reclamation zone and tailing zone） located at the lead-zine mine in Changhua. Based on total and bioavailable heavy metals （Pb, Zn, Cu and Cd） in soils, the correlation of total content with bioavailable content was analyzed, and their pollution characteristics were assessed by methods of single factor pollution index, Nemerow pollution index, geological accumulation index and potential ecological risk index.[Results] （i） The surface soils were polluted by Pb, Zn, Cu, Cd in different degrees, and the overall trend of the contents of the 4 heavy metals was in order of Cd 〉 Pb 〉 Zn 〉 Cu. The average excess multiple of heavy metals of total and bioavailable content in soils were in the order of peripheral zone 〉 tailing zone 〉 reclaimed zone, and their pollution degrees were tailing zone 〉 peripheral zone 〉 reclaimed zone. （ii） In general, the total and bioavailable contents of Pb, Zn, Cu, Cd showed a significant correlation, but were not correlated in each study zone. （iii） Pollution degrees of the study zones were in the order of tailing zone 〉 peripheral zone 〉 reclamation zone. The pollutions of heavy metals Pb and Cd were more serious, especially Cd reached high levels of pollution degree, and the pollution degrees of Zn, Cu were lighter. Contributors of ecological risk were mainly Cd, Pb and Cu, and the contribution of Cd achieved more than 90 %, making it the main source of pollution.[Conclusions] The results not only revealed the pollution status of heavy metals in the surface soil of the abandoned coal mine, but also could provide scientific guidance for reasonable utilization and ecological recovery of the land.

Heavy metal concentrations in soils and plants in the vicinity of Arufu lead-zinc mine, Middle Benue Trough, Nigeria

This study focused on the influence of base metal mining on heavy metal levels in soils and plants in the vicinity of Arufu lead-zinc mine, Nigeria. Soil samples (0-15 cm depth) and plant samples were collected from cul-tivated farmlands in and around the mine, the unmineralized site and a nearby forest (the control site). The samples were analyzed for heavy metals (Fe, Zn, Mn, Cu, Pb, Cr and Cd) by Atomic Absorption Spectrophotometry (AAS). The physical properties of soils (pH and LOI) were also measured. Results showed that soils from cultivated farm-lands have neutral pH values (6.5-7.5), and low organic matter contents (<10%). Levels of Zn, Pb and Cd in culti-vated soils were higher than the concentrations obtained from the control site. These heavy metals are most probably sourced from mining and agricultural activities in the study area. Heavy metal concentrations measured in plant parts decreased in the order of rice leaves>cassava tubers>peelings. In the same plant species, metal levels decreased in the order of Zn>Fe>Mn>Cu>Pb>Cr>Cd. Most heavy metals were found in plant parts at average concentrations normally observed in plants grown in uncontaminated soil, however, elevated concentrations of Pb and Cd were found in a few cassava samples close to the mine dump. A stepwise linear regression analysis identified soil metal contents, pH and LOI as some of the factors influencing soil-plant metal uptake.

Feasibility of Simultaneous Application of Fuzzy Neural Network and TOPSIS Integrated Method in Potential Mapping of Lead and Zinc Mineralization in Isfahan-Khomein Metallogeny Zone

Iran is located on a silver, lead, and zinc belt and according to the latest studies holds 11 million tons of lead, zinc, and silver stones which constitute 4 percent of global resources. Considering that mineral materials are explored in an uncertain space, exploration investment risk is an inseparable part of these activities. The important fact is to minimize the effect of this undesired factor in exploration. To achieve this, it is required that exploration activities and withdrawals are performed in a certain framework in which risk minimization is considered. Using mineral potential modelling for determining promising zones which should be taken into consideration in more detailed stages could make achieving the purpose possibly. This work is aimed at applying fuzzy neural network and TOPSIS methods simultaneously in order to explore zinc and lead resources. In this article, geological, telemetry, geophysics, and geochemistry data is integrated using fuzzy-neural network (neuro fuzzy) and using TOPSIS method rating for lead and zinc ore deposit potential mapping in Isfahan-Khomein strip which has been introduced as one of zinc and leads mineral scopes in Iran. This area which is composed of several zinc and lead ore deposits has been considered as the target area. Fuzzy integration results of zinc and lead mineralization witness layers confirm the relatively high potential of lead and zinc mineralization in this region having a northwest-southeast trend and involving more than 90 percent of the known indices and ore deposits of the region. In this research, it was shown that the results of TOPSIS-Neuro-Fuzzy integrated model (a combination of neural network and fuzzy logic) have increased the resolution of talented areas from the areas with no mineralization potential in comparison with the fuzzy method individually.

New Constraints on the Environmental Impact of Iron Oxides and Lead-Zinc Mines in Red Sea Hills,Egypt

Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimate the transportations of these minerals. Fourteen soil samples and fifteen plant samples were collected from sites located in the basin and also in neighboring area and chemically analyzed.In

Self-supported VO_(2) on polydopamine-derived pyroprotein-based fibers for ultrastable and flexible aqueous zinc-ion batteries

A conventional electrode composite for rechargeable zinc-ion batteries(ZIBs)includes a binder for strong adhesion between the electrode material and the current collector.However,the introduction of a binder leads to electrochemical inactivity and low electrical conductivity,resulting in the decay of the capacity and a low rate capability.We present a binder-and conducting agent-free VO_(2) composite electrode using in situ polymerization of dopamine on a flexible current collector of pyroprotein-based fibers.The as-fabricated composite electrode was used as a substrate for the direct growth of VO_(2) as a self-supported form on polydopamine-derived pyroprotein-based fibers(pp-fibers@VO_(2)(B)).It has a high conductivity and flexible nature as a current collector and moderate binding without conventional binders and conducting agents for the VO_(2)(B) cathode.In addition,their electrochemical mechanism was elucidated.Their energy storage is induced by Zn^(2+)/H^(+) coinsertion during discharging,which can be confirmed by the lattice expansion,the formation of by-products including Zn_(x)(OTf)_(y)(OH)_(2x−y)·nH_(2)O,and the reduction of V^(4+)to V^(3+).Furthermore,the assembled Zn//pp-fibers@VO_(2)(B) pouch cells have excellent flexibility and stable electrochemical performance under various bending states,showing application possibilities for portable and wearable power sources.

Double-Doped Carbon-Based Electrodes with Nitrogen and Oxygen to Boost the Areal Capacity of Zinc-Bromine Flow Batteries

Ensuring a stable power output from renewable energy sources,such as wind and solar energy,depends on the development of large-scale and long-duration energy storage devices.Zinc–bromine fl ow batteries(ZBFBs)have emerged as cost-eff ective and high-energy-density solutions,replacing expensive all-vanadium fl ow batteries.However,uneven Zn deposition during charging results in the formation of problematic Zn dendrites,leading to mass transport polarization and self-discharge.Stable Zn plating and stripping are essential for the successful operation of high-areal-capacity ZBFBs.In this study,we successfully synthesized nitrogen and oxygen co-doped functional carbon felt(NOCF4)electrode through the oxidative polymerization of dopamine,followed by calcination under ambient conditions.The NOCF4 electrode eff ectively facilitates effi cient“shuttle deposition”of Zn during charging,signifi cantly enhancing the areal capacity of the electrode.Remarkably,ZBFBs utilizing NOCF4 as the anode material exhibited stable cycling performance for 40 cycles(approximately 240 h)at an areal capacity of 60 mA h/cm^(2).Even at a high areal capacity of 130 mA h/cm^(2),an impressive energy effi ciency of 76.98%was achieved.These fi ndings provide a promising pathway for the development of high-areal-capacity ZBFBs for advanced energy storage systems.

Estimation of lead and zinc emissions from mineral exploitation based on characteristics of lead/zinc deposits in China

Nonferrous mining activities are some of the largest sources of heavy metals emissions into the environment and China is one of the largest producers and consumers of lead and zinc in the world.The cumulative productions and emissions of lead and zinc from mining-related activities in China were estimated.Up to 2007,the cumulative productions of lead and zinc in China were estimated to be about 6.69 and 12.59 Mt,respectively;and about 1.62 Mt lead and 3.32 Mt zinc emitted into the ambient environment during the mining,processing and smelting activities,representing 24.39% and 26.36% cumulative production,respectively.Among these three types of mining-related activities,mineral processing contributes the most to the total emission of 50.67% lead and 45.51% zinc.

Technological mineralogy and environmental activity of zinc leaching residue from zinc hydrometallurgical process

Chemical, physical, structural and morphological properties of zinc leaching residue were examined by the combination of various detection means such as AAS, XRF, XRD, M？ssbauer spectrometry, SEM-EDS, TG-DSC, XPS and FTIR. The toxicity characteristic leaching procedure （TCLP） was used to investigate the environmental activity of zinc leaching residue for a short contact time. The phase composition analysis indicated that the zinc leaching residue mainly consists of super refined flocculent particles including zinc ferrite, sulfate and silicate. The physical structural analysis showed that it has a thermal instability and strong water absorption properties. The results of TCLP indicated that the amounts of Zn and Cd in the leaching solution exceed 40 and 90 times of limit, respectively, which demonstrate that this residue is unstable in weak acidic environment for a short contact time.

Occurrence of lead and silver minerals and their interaction with xanthate in slurry of zinc electrolysis anode slime

The background pulp potential of zinc anode slime,and its influence on the occurrence of lead,silver and xanthate,were investigated with thermodynamic method.The thermodynamic conclusion and XRD analysis pointed out that in zinc anode slime,the thermodynamically stable compound of xanthate is dixanthogen,anglesite is the only mineral of lead,and kerargyrite is one of silver minerals occurring.Microflotation tests on single minerals of anglesite and kerargyrite in sulfuric acid solution by amyl dixanthogen indicated that dixanthogen has a much stronger collecting ability to kerargyrite than to anglesite.Molecular dynamic simulation indicated that amyl dixanthogen can only be adsorbed on the surface of kerargyrite in the presence of SO42-.The FTIR tests also verified the selective adsorption of amyl dixanthogen on the surface of kerargyrite in the presence of SO42-.

Kinetics of Neutralization of Polymetallic Mining Discharges from the Perkoa Zinc Deposit in Central-Western Burkina Faso

Oxidized and acidic mining discharges(pH between 4 and 5)from the Perkoa zinc mine in Burkina Faso consisting of waste rock,crusher rejects and mining tailings were sampled and used for neutralization tests with calcareous dolomite(for six months).The mining discharges and the calcareous dolomite were previously characterized.Columns of 60 cm length and 15 cm diameter were used for the tests.Then,2.62 kg of calcareous dolomite was deposited on the mining discharges in each column.Two liters of deionized water are added every 15 days to each column.Samples were taken at the outlet of the columns at time intervals and then analyzed to assess the evolution of pH,electrical conductivity and contents of PHEs(Potentially Harmful Elements)over time.Following the neutralization tests on solid mining discharges,neutralization tests were also carried out on acid leachates resulting from the oxidation of these same solid mining discharges with calcareous dolomite.The results show that calcareous dolomite is very effective for the neutralization of SR(Sterile Discharges)and the precipitation of PHEs contained therein.It is also effective in buffering acidic effluents from these sterile discharges.As for other mining discharges(crusher rejects and mining residues),although calcareous dolomite is not effective in neutralizing these oxidized and acidic solid discharges,it is however effective in precipitating PHEs such as arsenic and lead.Calcareous dolomite is also effective in buffering acid leachates from these oxidized and acidic mining discharges(crusher rejects and mining tailings).

The Effects of Three Mineral Nitrogen Sources and Zinc on Maize and Wheat Straw Decomposition and Soil Organic Carbon

The incorporation of straw in cultivated ifelds can potentially improve soil quality and crop yield. However, the presence of recalcitrant carbon compounds in straw slow its decomposition rate. The objective of this study was to determine the effects of different nitrogen sources, with and without the application of zinc, on straw decomposition and soil quality. Soils were treated with three different nitrogen sources, with and without zinc： urea （CO（NH2）2）, ammonium sulfate （（NH4）2SO4）, and ammonium chloride （NH4Cl）. The combined treatments were as follows：maize （M） and wheat （W） straw incorporated into urea-, ammonium sulfate-, or ammonium chloride-treated soil （U, S, and C, respectively） with and without zinc （Z） （MU, MUZ, WU, WUZ;MS, MSZ, WS, WSZ;MC, MCZ, WC, WCZ, respectively）;straw with zinc only （MZ, WZ）;straw with untreated soil （MS, WS）;and soil-only or control conditions （NT）. The experiment consisted of 17 treatments with four replications. Each pot contained 150 g soil and 1.125 g straw, had a moisture content of 80%of the ifeld capacity, and was incubated for 53 days at 25°C. The rates of CO2-C emission, cumulative CO2-C evolution, total CO2 production in the soils of different treatments were measured to infer decomposition rates. The total organic carbon （TOC）, labile organic carbon （LOC）, and soil microbial biomass in the soils of different treatments were measured to infer soil quality. All results were signiifcantly different （P〈0.05） with the exception of the labile organic carbon （LOC）. The maize and wheat straw showed different patterns in CO2 evolution rates. For both straw types, Zn had a synergic effect with U, but an antagonistic effect with the other N sources as determined by the total CO2 produced. The MUZ treatment showed the highest decomposition rate and cumulative CO2 concentration （1 120.29 mg/pot）, whereas the WACZ treatment had the lowest cumulative CO2 concentration （1 040.57 mg/pot）. The addition of NH4Cl resulted in the highest total organic carbon （TOC） concentration （11.59 mg kg-1）. The incorporation of wheat straw resulted in higher microbial biomass accumulation in soils relative to that of the maize straw application. The results demonstrate that mineral N sources can affect the ability of microorganisms to decompose straw, as well as the soil carbon concentrations.

Synthesis, Structure, and Luminescent and Dielectric Properties of a Novel 1D Chain Zinc(Ⅱ) Complex {[Zn(DCImPyO)·(H_2O)_2·]·H_3O}_n

Under hydrothermal conditions, 4-（4,5-dicarboxy-lH-imidazol-2-yl）pyridine 1-oxide （H3DCImPyO） reacted with ZnC12 to give the 1D chain complex {[Zn（DCImPyO）·（H2O）2·]·H3O}n （1）. Single-crystal X-ray determination shows that complex 1 crystallizes in the monoclinic system, space group P21/c with a = 9.488（2）, b = 13.247（3）, c = 12.959（4） A, β = 126.716（19）°, Z = 4, V= 1305.6（6）/k3, C10H11N3O8Zn, Dc = 1.865 g/cm3, Mr = 366.61, 2（MoKa） = 0.71073 A, μ= 1.930 mm1, F（000） = 744, R = 0.0472 and wR = 0.1487. Fluorescent analysis showed an intense emission band at 422 nm when the exciting radiation was set at 378 nm. Dielectric constant of complex 1 was measured at different frequencies with temperature variation.

Photoluminescence and thermoluminescence properties of dysprosium doped zinc metaborate phosphors

Polycrystalline powder samples of dysprosium doped Zn（BO2）2 phosphors were prepared by solid state reaction in air at high temperature and characterized by X-ray powder diffraction. The IR, Photoluminescence （PL）, diffuse reflectance and three-dimensional （3D） thermoluminescence （TL） emission spectrum after 60^Co gamma ray irradiation were investigated. The characteristic 3D TL emission bands at about 425, 481 and 573 um with a main emission band of around 573 um were attributed to the host emission, 4^F9/2→6H15/2 and F9/2→6^H13/2 f-f transitions of Dy^3＋ ions. No emission from Dy^2＋ ions was observed in the measurement wavelength range. The TL-dose response of the Zn（BO2）2：Dy polycrystalline powder sample to gamma ray radiation in the range from 1 to 100 Gy at clinical dose levels was almost linear. The experimental results showed that Zn（BO2）2：Dy had potential use as the materials of gamma-ray thermoluminescence dosimeter （TLD） for clinical dosimetry.

Extraction of metals from a zinc smelting slag using two-step procedure combining acid and ethylene diaminetetraacetic acid disodium

A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.

Zinc bioleaching from an iron concentrate using Acidithiobacillus ferrooxidans strain from Hercules Mine of Coahuila,Mexico

The iron concentrate from Hercules Mine of Coahuila,Mexico,which mainly contained pyrite and pyrrhotite,was treated by the bioleaching process using native strain Acidithiobacillus ferrooxidans （A.ferrooxidans） to determine the ability of these bacteria on the leaching of zinc.The native bacteria were isolated from the iron concentrate of the mine.The bioleaching experiments were carried out in shake flasks to analyze the effects of pH values,pulp density,and the ferrous sulfate concentration on the bioleaching process.The results obtained by microbial kinetic analyses for the evaluation of some aspects of zinc leaching show that the native bacteria A.ferrooxidans,which is enriched with a 9K Silverman medium under the optimum conditions of pH 2.0,20 g/L pulp density,and 40 g/L FeSO4,increases the zinc extraction considerably observed by monitoring during15 d,i.e.,the zinc concentration has a decrease of about 95% in the iron concentrate.

Functional analysis and drug response to zinc and D-penicillamine in stable ATP7B mutant hepatic cell lines

AIM: To study the effect of anti-copper treatment for survival of hepatic cells expressing different ATP7 B mutations in cell culture. METHODS: The most common Wilson disease(WD) mutations p.H1069 Q, p.R778 L and p.C271*, found in the ATP7 B gene encoding a liver copper transporter, were studied. The mutations represent major genotypes of the United States and Europe, China, and India, respectively. A human hepatoma cell line previously established to carry a knockout of ATP7 B was used to stably express WD mutants. m RNA and protein expression of mutant ATP7 B, survival of cells, apoptosis, and protein trafficking were determined.RESULTS: Low temperature increased ATP7 B protein expression in several mutants. Intracellular ATP7 B localization was significantly impaired in the mutants. Mutants were classified as high, moderate, and no survival based on their viability on exposure to toxic copper. Survival of mutant p.H1069 Q and to a lesser extent p.C271* improved by D-penicillamine(DPA) treatment, while mutant p.R778 L showed a pronounced response to zinc(Zn) treatment. Overall, DPA treatment resulted in higher cell survival as compared to Zn treatment; however, only combined Zn + DPA treatment fully restored cell viability. CONCLUSION: The data indicate that the basic impact of a genotype might be characterized by analysis of mutant hepatic cell lines.

Zinc Borohydride-Ionic Liquid: Stable and Efficient System for Reductive Reaction of Aldehydes with Primary Amines to Corresponding Secondary Amines

Ionic liquids（ILs） are attracting much attention in various fields of chemical synthesis, electrochemical applications, liquid-liquid extractions, as well as biotransformations. Among those fields, the application of ILs as the potential green solvent for a wide variety of synthetic processes is an area of intense researches. High yield, high selectivity, and good catalytic charac-teristics have usually been achieved. After the isolation of products, ILs can usually be recovered and recycled many times by simple treating procedures, such as, filtration, extraction, and dryness.

A Photoluminescent Bimetallic Zinc-pyridinedicarboxylate:Diverse Supramolecular Motifs from Distinct Hydrogen Bonds

A cyclic bimetallic metal-organic complex [Zn（C）（H-fmpdc）（H2O）]2·2H2O （fmpdc = 4-（furan-2-yl）-2,6-dimethylpyridine-3,5-dicarboxylate） was synthesized and characterized by single-crystal X-ray analysis. The compound crystallizes in orthorhombic, space group Pbca with a = 12.905（2）, b = 14.774（3）, c = 16.833（3）A, V= 3029.4（10）A^3 Z = 4, Dc = 1.644 g/cm^3, F（000） = 1616, R = 0.0347 and wR = 0.0956 （I 〉 2σ（I））. There exist diverse supramolecular motifs （1-D, 2-D and 3-D） from distinct hydrogen bonds in the crystal structure of the title compound. The furanyl group has obvious contribution to the red-shift in the photoluminescent spectrum of the H2fmpdc ligand. The title compound 1 shows strong photoluminescence with emission maximum at 2 = 402 nm （λex.max = 367 nm）.