Chemical properties of heavy metals in typical hospital waste incinerator ashes in China

Incineration has become the main mechanism for hospital waste (HW) disposal in China after the outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003. However, little information is available on the chemical properties of the resulting ashes. In the present study, 22HW ash samples, including 14 samples of bottom ash and eight samples of fly ash, were collected from four typical HW incineration plants located across China. Chemical analysis indicated that the HW ashes contained large amounts of metal salts of Al, Ca, Fe, K, Mg, Na with a concentration range of 1.8-315gkg(-1). Furthermore, the ashes contained high concentrations of heavy metals such as Ag, As, Ba, Bi, Cd, Cr, Cu, Mn, Ni, Pb, Ti, Sb, Sn, Sr, Zn with a vast range of 1.1-121,411mgkg(-1), with higher concentrations found in the fly ash samples. Sequential extraction results showed that Ba, Cr, Ni and Sn are present in the residual fraction, while Cd existed in the exchangeable and carbonate fractions. As, Mn, Zn existed in the Fe-Mn oxide fraction, Pb was present in the Fe-Mn oxide and residual fractions, and Cu was present in the organic matter fraction. Furthermore, toxicity characteristic leaching procedure (TCLP) results indicated that leached amounts of Cd, Cu and Pb from almost all fly ash samples exceeded the USEPA regulated levels. A comparison between the HW ashes and municipal solid waste (MSW) ash showed that both HW bottom ash and fly ash contained higher concentrations of Ag, As, Bi, Cd, Cr, Cu, Pb, Ti, and Zn. This research provides critical information for appropriate HW incineration ash management plans.     

煤燃烧过程中金属元素迁移特性

利用ICP-AES光谱仪对原煤、飞灰和底灰中铝、钾、钙、镁、铁、锰、锌、铜、硒、铬、砷等11种元素的含量进行了分析；对上述元素在煤燃烧过程中的迁移挥发特性进行了讨论，结果是钙、锰、铁挥发性较小，主要沉积在底灰中，而锌、铜挥发性较大，其他元素属于中等挥发性。     

Metal mobilization from municipal solid waste incineration bottom ash through metal complexation with organic and inorganic ligands

As a first step in the development of ligand-assisted removal of heavy metals from municipal solid waste incineration bottom ash under alkaline conditions, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium oxalate, ammonium citrate, urea, and mixtures of ammonium salts and urea were examined to find which ligands could promote the leachability of elements, including heavy metals, and which elements could be mobilized through complexation. Ammonium citrate promoted the mobilization of Cr, Cu, Mn, P, Sb, and especially Fe. Ammonium nitrate accelerated Mg leachability significantly. Under the conditions used in this study, counter anions seemed to contribute mainly to the complexation. When a mixture of ammonium citrate and urea was utilized, a coexistence effect appeared on Fe mobilization. Although the correlation analysis of leaching test results showed a strong correlation among Cr, Cu, Fe, Mn, and P, X-ray diffraction analysis partially supported the correlation between Fe and Mn only.     

Leaching of metals from fly ashes in the presence of complexing agents

The leachability of some metals (Al, As, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Ti, Zn) from fly ashes was studied in the presence of ethylenediamine tetraacetic acid (EDTA) and naturally occurring complexing agents-humic acids (HAs). Secondary complex-forming equilibria taking place in the leachates increase significantly the leached amounts of most metals. Kinetic experiments showed that almost the whole "available" amounts of metals are leached from fly ash within a time period of several hours (mostly within 20 h), with exceptions of matrix constituents (typically aluminium), which are released more slowly.     

Laboratory study on the leaching potential of spent alkaline batteries using a MSW landfill leachate

Two leaching tests were carried out, one with whole batteries and another with cross-cut batteries. In both cases, NEN 7343 (a Nederland’s Standard) procedure was followed using a municipal solid waste (MSW) landfill leachate as extraction solution. Seven fractions were collected corresponding to cumulative liquid/solid (L/S) ratio from 0.1 to 10.0. Those fractions were separately characterized in terms of pH, conductivity, redox potential, density, sulphate, chloride, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn. Results showed that the influence of the alkaline batteries in the landfill leachate composition varies with their physical integrity and with the L/S ratio, and several variations were observed throughout the tests. The leachate pH and redox potential increased as result of the contact with batteries, particularly pH in the test with the cross-cut batteries. The leachate density and conductivity did not change significantly with the whole batteries, in contrast with the test with cross-cut batteries.     

Heavy metal mobility and potential availability in animal manure: using a sequential extraction procedure

In this study, dairy cow manure, goat manure, and chicken manure were collected from three farms and analyzed to find out the concentration of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn. The concentration and potential of mobility and availability of heavy metals were studied in the animal manure samples. BCR Sequential extraction procedure was used to determine the binding forms of the metals. In this study, pseudo total concentrations of Mn and Zn were found out to be predominant in all the types of animal manure samples. According to the results, it was traced that Cr, Cu, and Ni were observed to be at the second highest level while Cd, Co, and Pb were seen at the lowest level in all the manure samples. When extractable amounts of heavy metals are taken into consideration, it is seen that the amount of the mobile fractions of heavy metals except for Cr and Ni are higher in comparison with that of immobile fraction in all the animal manure samples. It was also viewed that Mn, Cd, and Zn are more available in dairy cow manure and chicken manure whereas Cd, Co, and Mn are more available in goat manure.     

Enrichment of elements in industrial waste incineration bottom ashes obtained from three different types of incinerators,as studied by ICP-AES and ICP-MS

The elemental composition of the industrial waste incineration bottom ash (IWIBA) samples collected from three different types of incinerator with different kinds of wastes were compared. The major-to-ultratrace elements in the IWIBA samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). As a result, ca. 40 elements in the concentration range from milligrams per gram to submicrograms per gram could be determined with relative standard deviations of less than 5%. The IWIBA sample from petrochemical wastes contained lower concentrations of the elements, because fewer mineral constituents were contained in the input waste materials. On the contrary, the elemental concentrations in the IWIBA sample from industrial solid wastes provided the highest values for most elements, while the elemental compositions of the IWIBA sample from food wastes were similar to those of municipal solid waste incineration bottom ash. In addition, it was found from the analytical results that the levels of various heavy metals such as Cr, Mn, Fe, Ni, Cu, As, Zr, Mo, Sb, Ba, and Pb were higher in the IWIBA samples than in municipal solid waste incineration bottom ash. The enrichment factors of the elements in the IWIBA samples were estimated from the analytical results to compare the elemental distributions in incineration bottom ashes in relation to their mining influence factors, which are the indices for human use of the elements.     

Vitrification for reclaiming spent alkaline batteries

The object of this study is to stabilize spent alkaline batteries and to recover useful metals. A blend of dolomite, limestone, and cullet was added to act as a reductant and a glass matrix former in vitrification. Specimens were vitrified using an electrical heating furnace at 1400 °C and the output products included slag, ingot, flue gas, and fly ash. The major constituents of the slag were Ca, Mn, and Si, and the results of the toxicity leaching characteristics met the standards in Taiwan. The ingot was a good material for use in production of stainless steel, due to being mainly composed of Fe and Mn. For the fly ash, the high level of Zn makes it economical to recover. The distribution of metals indicated that most of Co, Cr, Cu, Fe, Mn, and Ni moved to the ingot, while Al, Ca, Mg, and Si stayed in the slag; Hg vaporized as gas phase into the flue gas; and Cd, Pb, and Zn were predominately in the fly ash. Recovery efficiency for Fe and Zn was >90% and the results show that vitrification is a promising technology for reclaiming spent alkaline batteries.     

Fractionation of heavy metals in sludge from anaerobic wastewater stabilization ponds in southern Spain

The analysis of heavy metals is a very important task to assess the potential environmental and health risk associated with the sludge coming from wastewater treatment plants (WWTPs). However, it is necessary to apply sequential extraction techniques to obtain suitable information about their bioavailability or toxicity. In this paper, a sequential extraction scheme according to the Standard, Measurements and Testing Programme of the European Commission was applied to sludge samples collected from ten anaerobic wastewater stabilization ponds (WSPs) located in southern Spain. Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Ti and Zn were determined in the sludge extracts by inductively coupled plasma atomic emission spectrometry. In relation to current international legislation for the use of sludge for agricultural purposes, none of the metal concentrations exceeded maximum permitted levels. Overall, heavy metals were mainly associated with the two less-available fractions (34% oxidizable metal and 55% residual metal). Only Mn and Zn showed the highest share of the available (exchangeable and reducible) fractions (25-48%).     

Metals in Sediments from the Stockholm Region: Geographical Pollution Patterns and Time Trends

The city of Stockholm is intersected and surrounded by water.Freshwater flows eastward and mixes with slightly brackish water in central Stockholm to finally reach the Baltic Sea. Inorder to estimate the magnitude and geographical impact of Stockholm as a source of metals to the aquatic environments, sediments from 117 stations in the Stockholm region have beenanalysed for metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn).This paper reports on the geographical pollution pattern and onthe time trends in metal pollution in Stockholm during the 20th century. Stockholm is a strong source of Cd, Cu, Hg,Pb and Zn whereas the Cr concentrations are moderately perturbed.In contrast, the concentrations of As, Co, and Ni are in generalclose to preindustrial levels. The concentrations of Cd, Cu, Hg,Pb and Zn are highest in central Stockholm and eastwards (i.e., in the water flow direction). Sediments upstream of Stockholm andin lakes that are not hydrologically connected to central Stockholm show a significantly lower impact. This may be indicative of metals emitted in Stockholm mainly being transported by the water route. Of Cd, Hg, Pb, and Zn, Cd showsthe most pronounced decline in accumulation rates over the lasttwo decades.     

添加CaO对燃煤重金属元素富集效果的影响

选取CaO作为吸附剂,探究了不同燃烧温度下添加CaO对重金属元素在燃煤灰渣中富集效果的影响规律。实验结果表明:添加CaO对重金属元素Cr未起到富集作用,而对Mn,Ni,Cu,Zn,As,Cd,Pb 7种重金属元素的富集效果显著;随燃烧温度的升高,CaO对各赋存形态的Mn,Ni,Cu,Zn,As的富集效果先变好而后变差,对各赋存形态的Cd和Pb的富集效果越来越好;CaO添加比(预处理后的CaO颗粒与预处理后的原煤的质量比)越大,CaO对Mn,Ni,Cu,Zn,As,Cd,Pb的富集效果越好,燃烧温度为850℃时的最佳CaO添加比为4%。     

Field investigation of the quality of fresh and aged leachates from selected landfills receiving e-waste in an arid climate

The management of electronic waste (e-waste) is a serious problem worldwide and much of it is landfilled. A survey of four selected landfills in an arid region of South Australia was conducted to determine the proportion of e-waste in municipal waste and the properties of each landfill site. Leachate and groundwater samples were collected upgradient and downgradient of the landfills for analysis of polybrominated diphenyl ethers (PBDEs) and 14 metals and metalloids, including Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, V and Zn. Our data demonstrate that the selected landfills in South Australia continue to receive municipal waste containing in excess of 6%, or 25,000 tonnes per year, of e-waste. The leachates and groundwater collected from the landfills contained significantly elevated concentrations of Pb with the highest concentration in groundwater of 38 μg/l, almost four times higher than the Australian drinking water guideline of 10 μg/l. The presence of PBDEs was detected in both leachate and groundwater samples. Total PBDEs values of 2.13–59.75 ng/l in leachate samples were 10 times higher than in groundwater samples, which recorded a range of 0.41–6.53 ng/l at all sites. Moreover, the concentrations of metals and metalloids in sampled groundwater contained elevated levels of Al, As, Fe, Ni and Pb that exceeded Australian drinking water guideline values. For these reasons potential leaching of these contaminants is of concern and while difficult to attribute elevated contaminant levels to e-waste, we do not recommend continued disposal of e-waste in old landfills that were not originally designed to contain leachates. The survey also revealed temporal variation in the electrical conductivity and concentrations of As, Cd and Pb present in leachates of landfills in arid Mediterranean climates. These results are consistent with the marked variations in rainfall patterns observed for such climates. The solute concentration (EC and other ions including As, Cd and Pb) declines in the leachates during wet winter months (June to September), in contrast to tropical countries where such changes are observed during wet summer months.     

Chemical changes in different types of coal ash during prolonged,large scale,contact with seawater

In this study, we followed the chemical changes occurring in coal ash exposed to prolonged (300 days), large scale, contact with running seawater. Four major components (Al, Ca, Mg, Fe) and seven minor and trace elements (Cd, Cr, Cu, Mn, Zn, Pb, Hg) were measured in four coal ash types: fly and bottom ash freshly obtained from coal-fired power plant, and old ash (crushed and blocks) recovered from the sea after 3-5 years contact with seawater. Changes occurred in the chemical composition of the coal ash along the experiment: Fe increased in fresh ash, Al increased in old ash and Ca increased in all ash types except old ash blocks. Cu and Hg decreased in fresh fly ash while Cr increased, Cd decreased in all ash types except bottom ash, and Mn decreased in bottom ash. Most of the changes occurred in the fresh fly ash, and not in the old ash, indicating equilibrium after prior exposure to seawater. In addition, more changes occurred in fresh fly ash than in bottom ash, emphasizing the differences between the two ash types. While the changes in the concentrations of the major elements may be an indication of the integrity of the ash matrix, the only elements of environmental significance released to the environment were Hg and Cd. However, calculated seawater concentrations were much lower than seawater quality criteria and therefore the coal ash was considered suitable for marine applications concerning seawater quality.     

Stabilization of As, Cr, Cu, Pb and Zn in soil using amendments--a review

The spread of contaminants in soil can be hindered by the soil stabilization technique. Contaminant immobilizing amendments decrease trace element leaching and their bioavailability by inducing various sorption processes: adsorption to mineral surfaces, formation of stable complexes with organic ligands, surface precipitation and ion exchange. Precipitation as salts and co-precipitation can also contribute to reducing contaminant mobility. The technique can be used in in situ and ex situ applications to reclaim and re-vegetate industrially devastated areas and mine-spoils, improve soil quality and reduce contaminant mobility by stabilizing agents and a beneficial use of industrial by-products. This study is an overview of data published during the last five years on the immobilization of one metalloid, As, and four heavy metals, Cr, Cu, Pb and Zn, in soils. The most extensively studied amendments for As immobilization are Fe containing materials. The immobilization of As occurs through adsorption on Fe oxides by replacing the surface hydroxyl groups with the As ions, as well as by the formation of amorphous Fe(III) arsenates and/or insoluble secondary oxidation minerals. Cr stabilization mainly deals with Cr reduction from its toxic and mobile hexavalent form Cr(VI) to stable in natural environments Cr(III). The reduction is accelerated in soil by the presence of organic matter and divalent iron. Clays, carbonates, phosphates and Fe oxides were the common amendments tested for Cu immobilization. The suggested mechanisms of Cu retention were precipitation of Cu carbonates and oxy-hydroxides, ion exchange and formation of ternary cation-anion complexes on the surface of Fe and Al oxy-hydroxides. Most of the studies on Pb stabilization were performed using various phosphorus-containing amendments, which reduce the Pb mobility by ionic exchange and precipitation of pyromorphite-type minerals. Zn can be successfully immobilized in soil by phosphorus amendments and clays.     

Trace Metals in Different Crop/Cultivation Systems in Greece

Typical soils in Greece are neutral or alkaline and frequently are lime-rich, conditions that favour the accumulation of trace elements. The traditional use of metal-based fungicides in orchards and vineyards may have led to the accumulation of trace metals. Concentrations of Fe, Cu, Mn, Zn (aqua regia digestion) and some other soil parameters were measured in organically and conventionally cultivated soils (0–30 cm) from vineyards, olive groves and citrus groves of varying ages, and in uncultivated soils. Many vineyards and olive groves are situated in hilly or mountainous areas with sloping ground or terraces in contrastto citrus, which is cultivated in lower lying areas. Due to the difficulty of access, these crops often are cultivated extensively in both systems. Trace metal concentrations were found to lie withinthe ranges expected for the predominant soil types. Cu concentrations were relatively high (>100 mg kg^-1) in a few samples, but were not correlated with the age of the cultivation. A two-way ANOVA analysis showed larger differences in the mean concentrations of Cu, Mn and Zn between different crops (p≤ 0.001 for Cu, p≤ 0.05 for Zn, and p≤ 0.1 for Mn) than between different cultivation systems (no significant differences). The crop by cultivation interaction was not statistically significant for any metal (p > 0.8). Strong correlations (p≤ 0.001) were found between Fe, Mn and Zn and both clay concentration and CEC, although these relationshipswere not uniform throughout the different crop and cultivation systems. Concentrations of Cu were related to clay concentrations only for vineyards and to CEC only for citrus. Correlations were not found with organic matter or pH.     

Green algae of the genus Spirogyra: A potential absorbent for heavy metal from coal mine water

Algae have considerable capability for absorbing heavy metals from wastewaters and are considered an effective treatment technology. Heavy metal absorption from coal mine water from the Bhowra Abandoned mine (open cast mine) and the Sudamdih Shaft mine (underground mine waters), both located in Dhanbad, India, by cells of Spirogyra was studied at different dilutions (100 percent, 80 percent, 60 percent, 40 percent, and 20 percent). In the present study, the following 18 metals were selected for analysis: aluminium (Al), arsenic (As), silver (Ag), barium (Ba), beryllium (Be), bismuth (Bi), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), gallium (Ga), indium (In), potassium (K), manganese (Mn), nickel (Ni), and vanadium (V). Accordingly, Al and K were found to be higher in concentration with respect to selected metals for both mine waters. The biosorption study revealed that higher amounts of Al, Bi, Co, Cs, Fe, Ga, Mn, Ni, and V were absorbed by algal biomass at 100 percent concentration from both mine waters. The maximum uptake of Cu, As, and Cd was measured at 60 percent, 40 percent, and 20 percent, respectively, for the Bhowra Abandoned mine water. The biosorption equilibrium study revealed that Ag, Al, Ba, Be, Bi, Co, Cr, Cs, Fe, Ga, In, K, Mn, Ni, and V were maximally absorbed by algal biomass at 100 percent concentration from Bhowra mine water, while the maximum uptake by the algal biomass measured for the Sudamidh coal mine water was for Al, As, Bi, Cu, Fe, and Mn at 100 percent concentration. The different physicochemical characteristics of mine water and drinking water standards was also studied. Accordingly, total dissolved solid and chemical oxygen demand concentrations exceeded the drinking water standards for water samples collected from both mines.     

Petrographic and spectroscopic characterization of phosphate-stabilized mine tailings from Leadville,Colorado

The use of soluble PO4(3-) and lime as a heavy metal chemical stabilization agent was evaluated for mine tailings from Leadville, Colorado. The tailings are from piles associated with the Wolftone and Maid of Erin mines; ore material that was originally mined around 1900, reprocessed in the 1940s, and now requires stabilization. The dominant minerals in the tailings are galena (PbS), cerrusite (PbCO3), pyromorphite (Pb5(PO4)3Cl), plumbojarosite (Pb0.5Fe3(SO4)2(OH)6), and chalcophanites ((Pb,Fe,Zn,Mn)Mn2O5 x 2H2O). The tailings were treated with soluble PO4(3-) and lime to convert soluble heavy metals (principally Pb, Zn, Cu, Cd) into insoluble metal phosphate precipitates. The treatment process caused bulk mineralogical transformations as well as the formation of a reaction rind around the particles dominated by Ca and P. Within the mineral grains, Fe-Pb phosphosulfates, Fe-Pb sulfates (plumbojarosite), and galena convert to Fe-Ca-Pb hydroxides. The Mn-Pb hydroxides and Mn-(+/-Fe)-Pb hydroxides (chalcophanites) undergo chemical alteration throughout the grains during treatment. Bulk and surface spectroscopies showed that the insoluble reaction products in the rind are tertiary metal phosphate (e.g. (Cu,Ca2)(PO4)2) and apatite (e.g. Pb5(PO4)3Cl) family minerals. pH-dependent leaching (pH 4,6,8) showed that the treatment was able to reduce equilibrium concentrations by factors of 3 to 150 for many metals; particularly Pb2+, Zn2+, Cd2+, and Cu2+. Geochemical thermodynamic equilibrium modeling showed that apatite family and tertiary metal phosphate phases act as controlling solids for the equilibrium concentrations of Ca2+, PO4(3-) Pb2+, Zn2+, Cd2+, and Cu2+ in the leachates during pH-dependent leaching. Both end members and ideal solid solutions were seen to be controlling solids.     

Metal Concentrations in Pore Water of the Lusatian Lignite Mining Sediments and Internal Metal Distribution in Juncus bulbosus

The aim of this study was to determine a suite of four metals (Fe, Mn, Zn, Cu) in the sediment, porewater and a pioneer plant (Juncus bulbosus) of Lusatian lignite mining lakes in eastern Germany. An attempt was made to understand the factors which affect element concentrations in the above- and below-ground biomass of Juncus bulbosus in an extreme environment. Water samples, sediments, porewater and plant material collected from two different mining lakes dominated by Juncus bulbosus species were analyzed for their elemental content. Additionally, scanning electron microscopy (SEM) and an energy-dispersive X-ray (EDX) detector were used to follow the internal metal distribution in the roots of Juncus plant. Results showed that sediment and porewater element concentrations in the lakes decreased in the order Fe > Mn > Zn and Cu. All the four elements were higher in the roots than in above-ground tissues, suggesting that iron plaque induced on roots under anaerobic conditions served as a metal reservoir, but not as an ultimate mechanism to control metal concentrations in the above-ground tissues. SEM and EDX analyses revealed that the rhizodermis, exodermis and endodermis cells regulate the traffic of transition metals and therefore avoid excess levels that are toxic to the plant in acidic mining-impacted lake sediments.     

Aerosol Composition Change due to Dust Storm: Measurements between 1992 and 1999 at Gosan,Korea

Aerosol composition change between dust storm and non duststorm periods is studied using the TSP (Total SuspendedParticulate) data measured at Gosan, Korea between 1992 and1999. The concentrations of elements measured between 1993and 1996 and those of ions between 1992 and 1999 duringdust storms are compared with those during non-dust stormperiods in spring (March, April, and May). Among theanalyzed ions, the concentrations of crustal species(potassium, calcium, magnesium, and chloride) andanthropogenic species (nitrate and non-sea salt (nss)-sulfate) increased when dust storm occurs while those ofammonium and sodium did not increase. Among the analyzedelements, the concentrations of crustal species (Fe, Al,Ca, Ti, and Zn) increased when dust storm occurs whilethose of anthropogenic species (Mn, V, Ni, Cu, Cd, and Cr)did not increase. The only anthropogenic element of whichconcentration increased during dust storm periods was Pb.It was found that the concentrations of nitrate and nss-sulfatewere highest during spring. Also, the ratio of theyearly average concentrations of nitrate to nss-sulfateincreases, probably due to the emission trend change innortheast Asia, especially, in China.     

Investigation of potentially toxic heavy metals in different organic wastes used to fertilize market garden crops

The benefits of using organic waste as fertilizer and soil amendment should be assessed together with the environmental impacts due to the possible presence of heavy metals (HMs). This study involved analysing major element and HM contents in raw and size-fractionated organic wastes (17 sewage sludges and composts) from developed and developing countries. The overall HM concentration pattern showed an asymmetric distribution due to the presence of some wastes with extremely high concentrations. HM concentrations were correlated with the size of cities or farms where the wastes had been produced, and HM were differentiated with respect to their origins (geogenic: Cr–Ni; anthropogenic agricultural and urban: Cu–Zn; anthropogenic urban: Cd–Pb). Size fractionation highlighted Cd, Cu, Zn and Pb accumulation in fine size fractions, while Cr and Ni were accumulated in the coarsest. HM associations with major elements revealed inorganic (Al, Fe, etc.) bearing phases for Cr and Ni, and sulfur or phosphorus species for Cd, Cu Pb and Zn.