Smelting Facility Research Articles

Air pollution control and flue gas desulfurization residues from Polish copper smelting facility as adsorbents of Pb(II) and Cu(II) from aqueous solutions

This study aimed at evaluation of air pollution control residues (APCR) and flue gas desulfurization residues (FGDR) from copper foundry in Southwestern Poland as adsorbents of Cu(II) and Pb(II) from simulated wastewater. Studies of the impact of pH and adsorbent dose, as well as sorption isotherms, and kinetic and thermodynamic studies were conducted in a series of batch experiments. The maximum adsorption capacities were equal to 42.9 mg g−1 Cu(II) and 124.4 mg g−1 Pb(II) for APCR and 98.8 mg g−1 Cu(II) and 124.7 mg g−1 Pb(II) for FGDR, which was comparable to mineral adsorbents examined in other studies. Adsorption isotherms followed the Langmuir model, except for Pb(II) for FGDR, which followed Freundlich model. Sorption kinetics for both materials was properly expressed by pseudo-second-order equation. Mean adsorption energy parameter suggested that the adsorption might have occurred via physical bonding. Thermodynamic study revealed that adsorption was spontaneous and endothermic for Cu(II) and not spontaneous and exothermic for Pb(II), with lower temperature favoring the process. The results suggested that both materials had high affinity towards Cu(II) and Pb(II) ions and could be conducted industrial scale research for consideration as potential adsorbents from aqueous solutions.

Chlorinated and Brominated Polycyclic Aromatic Hydrocarbons from Metallurgical Plants.

In this study, we investigated several metallurgical industries, including iron ore sintering, secondary aluminum smelting, and secondary lead smelting, as potential sources of Cl-PAHs and Br-PAHs. Stack gas emissions of 19 Cl-PAH and 19 Br-PAH congeners from the investigated metallurgical plants were in the ranges of 68.3-156 ng Nm-3 and 2.9-13.5 ng Nm-3, respectively. Cl/Br-PAHs in ambient air surrounding the investigated metallurgical plants were also quantified, and the ranges were 7.0-554 pg m-3 for Cl-PAHs and 3.0-126 pg m-3 for Br-PAHs. Toxic equivalent (TEQ) concentrations of Cl-PAHs and Br-PAHs in the ambient air samples were in the ranges of 0.03-3.61 pg TEQ m-3 and 0.001-0.23 pg TEQ m-3, respectively. These TEQs were slightly higher than or comparable to those of dioxins and dioxin-like compounds. Congener profiles of Cl-PAHs emitted from iron ore sintering, secondary aluminum smelting, and secondary lead smelting facilities were clarified and their congener profiles were obviously different from that from waste incinerators. Comparisons of Cl/Br-PAH congener profiles between surrounding air samples and stack gas emissions indicated that metallurgical emissions affected the surrounding environment to some extent.

Groundwater co-contaminant behavior of arsenic and selenium at a lead and zinc smelting facility

Co-contaminant behavior of arsenic (As) and selenium (Se) in groundwater is examined in this study at a former lead and zinc smelting facility. We collected water quality data, including concentrations of trace metals, major ions, and metalloid speciation, over a 15-year period to document long-term trends and relationships between As, Se, geochemical parameters, and other redox-sensitive trace metals. Concentrations of dissolved As and Se were negatively correlated (Kendall's Tau B correlation coefficient, r = −0.72) and showed a distinctive L-shaped relationship. High-concentration arsenic wells (>5 mg L−1) were characterized by intermediate oxidation-reduction conditions (75 < Eh < 275 mV), near-neutral pH (6.1–7.9), low Ca/Na ratios, elevated Fe and Mn concentrations, and high proportions of As(III) relative to total dissolved As. High-concentration Se wells (>500 μg L−1) were characterized by more positive Eh (305–500 mV), low Fe concentrations, and high proportions of As(V). Batch micocosm experiments showed that aquifer solids contain mineral surfaces and/or microbial communities capable of removing selenate from groundwater. Electron microprobe and Se K-edge X-ray absorption near-edge spectroscopic analyses demonstrated that Se was predominantly associated with elemental Se in the reduced aquifer solids. Factor analysis revealed three discernible groupings of trace metals. Group I includes U, Se, and nitrate-N, all of which are mobile under oxygenated to moderately oxygenated conditions. Group II includes elements that are mobile under Fe(III)-reducing conditions: Fe, total dissolved As, As(III), and ammonium-N. Group III elements (Mo, Sb, and V) showed mobility across the entire range of redox conditions encountered in site groundwater; As(V) clustered with this group of elements. Geochemical modeling suggests that As and Se species were in a state of disequilibrium with respect to measured parameters indicative of redox conditions, although predicted patterns of redox-controlled mobility and attenuation were confirmed. This analysis is important to better understand groundwater contaminant behavior in response to redox conditions ranging from oxic/suboxic to Fe(III)-reducing, but excluding sulfate-reducing conditions.

ANALISIS PENGARUH KEPEMILIKAN INSTITUSIONAL, DIVIDEND PAYOUT RATIO, TANGIBILITY, DAN UKURAN PERUSAHAAN TERHADAP KEBIJAKAN UTANG PADA PERUSAHAAN PERTAMBANGAN YANG TERDAFTAR DI BURSA EFEK INDONESIA TAHUN 2013 - 2015

Peraturan Pemerintah (PP) Nomor 1 Tahun 2017 which has been officially legalized by the Government of Indonesia in effort to encourage the establishment of smelter facilities in the country have an impact on mining companies, especially on the company's debt policy. This research aims to study the effect of institutional ownership, dividend payout ratio, tangibility, and firm size on company debt policy as measured by debt ratio. This research uses multiple linear regression analysis with secondary data in the form of annual reports and audited financial statement from mining sector companies listed on the Indonesia Stock Exchange in 2013-2015 period. From total population of 43 companies in the mining sector, 32 companies were selected to be the sample of this research with a total of 96 observations in 3 years. The results of this research indicate that from the four independent variables tested, institutional ownership and dividend payout ratio has an influence on debt policy, while tangibility and firm size have no influence on debt policy.

Particle size distributions of lead measured in battery manufacturing and secondary smelter facilities and implications in setting workplace lead exposure limits

ABSTRACTInhalation plays an important role in exposures to lead in airborne particulate matter in occupational settings, and particle size determines where and how much of airborne lead is deposited in the respiratory tract and how much is subsequently absorbed into the body. Although some occupational airborne lead particle size data have been published, limited information is available reflecting current workplace conditions in the U.S. To address this data gap, the Battery Council International (BCI) conducted workplace monitoring studies at nine lead acid battery manufacturing facilities (BMFs) and five secondary smelter facilities (SSFs) across the U.S. This article presents the results of the BCI studies focusing on the particle size distributions calculated from Personal Marple Impactor sampling data and particle deposition estimates in each of the three major respiratory tract regions derived using the Multiple-Path Particle Dosimetry model. The BCI data showed the presence of predominantly larger-sized particles in the work environments evaluated, with average mass median aerodynamic diameters (MMADs) ranging from 21–32 µm for the three BMF job categories and from 15–25 µm for the five SSF job categories tested. The BCI data also indicated that the percentage of lead mass measured at the sampled facilities in the submicron range (i.e., <1 µm, a particle size range associated with enhanced absorption of associated lead) was generally small. The estimated average percentages of lead mass in the submicron range for the tested job categories ranged from 0.8–3.3% at the BMFs and from 0.44–6.1% at the SSFs. Variability was observed in the particle size distributions across job categories and facilities, and sensitivity analyses were conducted to explore this variability. The BCI results were compared with results reported in the scientific literature. Screening-level analyses were also conducted to explore the overall degree of lead absorption potentially associated with the observed particle size distributions and to identify key issues associated with applying such data to set occupational exposure limits for lead.

Heavy metals in industrially emitted particulate matter in Ile-Ife, Nigeria

Iron and steel smelting facilities generate large quantities of airborne particulate matter (PM) through their various activities and production processes. The resulting PM that contains a variety of heavy metals has potentially detrimental impacts on human health and the environment. This study was conducted to assess the potential health effects of the pollution from the heavy metals in the airborne PM sampled in the vicinity of secondary smelting operations in Ile-Ife, Nigeria. X-ray fluorescence (XRF) was used to determine the elemental concentration of Pb, Cr, Cd, Zn, Mn, As, Fe, Cu, and Ni in the size-segregated PM samples. Pollution Indices (PI) consisting of Contamination Factor (CF), Degree of Contamination (DC) and Pollution Index Load (PLI) and Target Hazard Quotient (THQ) were employed to assess the pollution risk associated with the heavy metals in the PM. CF, DC and PLI values were 3< CF <6, >32 and >1, respectively for the three sites, indicating deterioration of the ambient air quality in the vicinity of the smelter. The heavy metals in the airborne PM pose a severe health risk to people living in vicinity of the facility and to its workers. The diminished air quality with the associated health risks directly depends on the industrial emissions from steel production and control measures are recommended to mitigate the likely risks.

Variation of natural radionuclides in non-ferrous fayalite slags during a one-month production period

The European Basic Safety Standards (EU-BSS) describes a set of NORM (Naturally Occurring Radioactive Material)-processing industries which produce residues known to be possibly enriched in NORs (Naturally Occurring Radionuclides). These residues can be used as a component in building materials aimed for public usage. The industrial processes, in which the residues are produced, are often complex and total monitoring can be challenging especially when the origin of the used raw materials varies. In this study the NORs present in non-ferrous fayalite slags of a secondary smelter facility, a NORM-processing industry according to the EU-BSS, were monitored daily during a one-month production period. In addition flue dust samples and feedstock samples, known to contain elevated levels of NORs, of the same period were measured. The survey involved the gamma-ray spectrometric analysis of the decay products from the 238U and 232Th decay chains, 235U and 40K using HPGe detectors. Secular equilibrium was observed for the slags, flue dust and feedstock samples in the 232Th decay chain, in contrast to the 238U decay chain. During the month in question the ratios of maximum over minimum activity concentration were 3.1 ± 0.5 for 40K, 4 ± 1 for 238U, 6 ± 1 for 226Ra, 13 ± 7 for 210Pb, 4.5 ± 0.6 for 228Ra and 4.7 ± 0.7 for 228Th for the slags. Even with the activity concentration of the feedstock material ranging up to 2.1 ± 0.3 kBq/kg for 238U, 1.6 ± 0.2 kBq for 226Ra, 22 ± 7 kBq/kg for 210Pb, 2.1 ± 0.2 kBq/kg for 228Ra and 2.0 ± 0.4 kBq/kg for 228Th, none of the slag samples exceeded the exemption/clearance levels of the EU-BSS and RP-122 part II, which can respectively provide guidance under equilibrium and in absence of equilibrium. As each NORM-processing industry has its own complexity and variability, the observed variations point out that one should approach one-time measurements or low frequency monitoring methods cautiously. Low frequency measurements should be optimised depending on the discharge of the batches. A follow up of the industrial process and its output can provide important insights to assure a limited public exposure upon application of these industrial residues.Finally a comparison is made with reported data on other metallurgical slags and the use of the slags in building materials is evaluated using the Activity Concentration Index (ACI) proposed by the EU-BSS.

A low-energy set-up for gamma-ray spectrometry of NORM tailored to the needs of a secondary smelting facility

A measurement station dedicated for quantitative radiological characterisation of naturally occurring radionuclides in a metallurgical company and based on gamma-ray spectrometry was developed. The station is intended for performing quality control of final non-ferrous metal products and for radiological checks of incoming materials. A low-background point-contact HPGe-detector was used and the signal was split in two branches to enable collecting simultaneously spectra with high amplification (for gamma-ray energies below 250keV) and low amplification.

Oral bioaccessibility of inorganic contaminants in waste dusts generated by laterite Ni ore smelting.

The laterite Ni ore smelting operations in Niquelândia and Barro Alto (Goiás State, Brazil) have produced large amounts of fine-grained smelting wastes, which have been stockpiled on dumps and in settling ponds. We investigated granulated slag dusts (n=5) and fly ash samples (n=4) with a special focus on their leaching behaviour in deionised water and on the in vitro bioaccessibility in a simulated gastric fluid, to assess the potential exposure risk for humans. Bulk chemical analyses indicated that both wastes contained significant amounts of contaminants: up to 2.6wt% Ni, 7580mg/kg Cr, and 508mg/kg Co. In only one fly ash sample, after 24h of leaching in deionised water, the concentrations of leached Ni exceeded the limit for hazardous waste according to EU legislation, whereas the other dusts were classified as inert wastes. Bioaccessible fractions (BAF) of the major contaminants (Ni, Co, and Cr) were quite low for the slag dusts and accounted for less than 2% of total concentrations. In contrast, BAF values were significantly higher for fly ash materials, which reached 13% for Ni and 19% for Co. Daily intakes via oral exposure, calculated for an adult (70kg, dust ingestion rate of 50mg/day), exceeded neither the tolerable daily intake (TDI) nor the background exposure limits for all of the studied contaminants. Only if a higher ingestion rate is assumed (e.g. 100mg dust per day for workers in the smelter), the TDI limit for Ni recently defined by European Food Safety Authority (196µg/day) was exceeded (324µg/day) for one fly ash sample. Our data indicate that there is only a limited risk to human health related to the ingestion of dust materials generated by laterite Ni ore smelting operations if appropriate safety measures are adopted at the waste disposal sites and within the smelter facility.

Soluble trace metals in aerosols over the tropical south-east Pacific offshore of Peru

Abstract. Bulk aerosol samples collected during cruise M91 of FS Meteor off the coast of Peru in December 2012 were analysed for their soluble trace metal (Fe, Al, Mn, Ti, Zn, V, Ni, Cu, Co, Cd, Pb, Th) and major ion (including NO3− and NH4+) content. These data are among the first recorded for trace metals in this relatively poorly studied region of the global marine atmosphere. To the north of ∼ 13° S, the concentrations of several elements (Fe, Ti, Zn, V, Ni, Pb) appear to be related to distance from the coast. At the south of the transect ( ∼ 15–16° S), elevated concentrations of Fe, Cu, Co, and Ni were observed, and we calculated dry deposition fluxes of soluble Cu approximately an order of magnitude higher than a recent model-based estimate of total Cu deposition to the region. The model did not take account of emissions from the large smelting facilities in the south of Peru and northern Chile, and our results may indicate that these facilities constitute an important source of trace metals to the region. Calculated dry deposition fluxes (3370–17800 and 16–107 nmol m−2 d−1 for inorganic nitrogen and soluble Fe respectively) indicated that atmospheric input to the waters of the Peru upwelling system contains an excess of Fe over N, with respect to phytoplankton requirements. This may be significant as primary production in these waters has been reported to be limited by Fe availability, but atmospheric deposition is unlikely to be the dominant source of Fe to the system.

Mercury flows in a zinc smelting facility in South Korea

To prepare for the international mercury convention, the characteristics of mercury emissions from a zinc smelting facility in South Korea have been reviewed and a material flow analysis (MFA) has been conducted in this research. As inputs into the mercury MFA study, zinc ores and sulfuric acid were examined, whereas wastewater sludge, effluence water, spent catalyst, and emissions from the casting and roasting processes were examined as outputs. Mercury concentrations extracted from end products like zinc ingots, cadmium ingots, and sulfuric acid were then analyzed. Our results showed that the wastewater sludge discharged from the zinc smelting process had a relatively higher concentration of mercury, indicating that the concentration of mercury was further enriched in the wastewater sludge. The wastes discharged through the zinc smelting process should be thoroughly controlled, as results of the MFA showed that approximately 89 % of the mercury contained in the original input was later found in the waste. According to this study, the higher the concentration of mercury within zinc ores at the input stage, the higher is the mercury concentration found in the wastewater sludge at the output stage.

Significance of measuring non-2,3,7,8-substituted PCDD/PCDF congeners and the identification of a new mechanism of formation for a high-temperature industrial process

Many studies involving polychlorinated dibenzo-p-dioxins and dibenzofurans (Cl4–Cl8) are limited to the 17 2,3,7,8-substituted congeners, which are used for the computation of the toxic equivalent concentration (TEQ) and often are the basis for regulatory actions. The values determined for total homolog groups may also be reported in some cases, e.g., Total Tetra-Dioxins, and such results provide some additional information but do not reveal the subtle details that can be derived from the study of individual congeners. There are 136 possible structures for tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans, including the 17 2,3,7,8-substituted congeners. In this work, the valuable role that inclusion of the other 119 congeners plays in understanding emission deviations (upsets) compared to normal operating conditions for a secondary aluminum smelter facility is illustrated. An exponential correlation was observed between the concentrations of specific non-2,3,7,8-substituted tetrachlorinated congeners (e.g., 2,3,6,7/3,4,6,7-TCDFs vs. 1,3,6,8-TCDD and 1,3,7,9-TCDD) and the TEQ-based emissions at the outlet of a baghouse pollution control device. The correlation possibly points to the additional and occasionally essential role played by metal-catalyzed stereoselective chlorination reactions taking place during the melting-purification process, as well as (conceivably) inside the air pollution control device. This chlorination in turn highlights not only the importance of the chlorine addition step and the kinetics involved with regard to regulating emission levels but also the role of measuring all 136 PCDD/F congeners.

Recycling of cathode ray tube panel glasses as aggregates of concrete blocks and clay bricks

While the cathode ray tube (CRT) funnel containing lead could be transported to a smelting facility to recover lead, which could be an available option in domestic, a proper technology to recycle a CRT panel must be developed. Thus, it was suggested that CRT panel glass be used as aggregates of concrete blocks and clay bricks. Samples of blocks and bricks were fabricated with CRT powders and tested to measure their strength and absorption rate to determine their qualities, and environmental soundness was determined by measuring the leaching rate of hazardous metals. For concrete blocks, CRT panel glass powders incorporated as aggregates up to 40 % replacing stone powder was proposed as the proper condition for manufacturing blocks. Around 2 % of CRT panel incorporated into clay brick to substitute Kaoline was suggested to fabricate the best quality of clay brick. Results of leaching test met the criteria with much less concentration of hazardous metals, even lead compound containing in the CRT funnel. To conclude, the use of CRT panel powder after crushing it to the proper size as an aggregate of concrete blocks or clay bricks could be one of the appropriate alternatives to recycle for CRT glass waste being generated drastically in a short term.

Power, Quiescence, and Pollution

The number of communities dealing with industrial pollution in the United States has increased dramatically over the past three decades. Environmental campaigns have consequentially emerged and so has research on successful mobilizing efforts. A gap remains, however, on cases where mobilization fails to materialize. In this article, we develop a typology of power’s multidimensional nature in an effort to address mechanisms by which elites prompt quiescence in the face of grievous injustice. We then analyze a case in point, Blackwell, Oklahoma—a community contaminated with lead, zinc, and cadmium from a decommissioned zinc smelter facility—and the proactive and coercive methods used to maintain local quiescence. Despite assurances that the community had been successfully remediated in the mid-1990s, residents learned in 2006 that environmental pollution continued to emanate from the facility. Our data come from in-depth interviews with community residents and city officials, participant observation, and document analysis. Findings highlight forms of control employed to keep citizens quiescent and to thwart the efforts of more vocal residents in the community.

Distribution of trace elements in particle size fractions for contaminated soils by a copper smelting from different zones of the Puchuncaví Valley (Chile)

Metal contents in soil samples are commonly used to evaluate contamination levels. However, the distribution of metals is dependent on particle size. We investigated the distribution of metals in various particle size fractions of the soil from four sites of the Puchuncaví Valley (Central Chile). The soil samples were segregated into size fractions ranging from 0.3 to 20μm and analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The results of the statistical analysis of the total metal concentrations indicated that the soil samples from Greda and Maitenes, the sites nearest the industrial sources, are the most contaminated. For these sites, the size-fractionated samples containing higher concentrations of Cu, Zn, As, and Pb were found in the finer fractions, suggesting anthropogenic depositions from smelter facilities. In addition, a high Ca concentration was observed in the finer fractions, which could be attributed to the technological approaches used to reduce the SO2 emissions from the roasting process of copper sulfide. The mineral composition of fine particles permitted the identification of Tenorite and Calcium oxide, which are most likely associated with smelting activities, confirming emission of enriched particulate matter from the copper smelter.

Combined analysis of modeled and monitored SO2 concentrations at a complex smelting facility

Vale Canada Limited owns and operates a large nickel smelting facility located in Sudbury, Ontario. This is a complex facility with many sources of SO2 emissions, including a mix of source types ranging from passive building roof vents to North America's tallest stack. In addition, as this facility performs batch operations, there is significant variability in the emission rates depending on the operations that are occurring. Although SO2 emission rates for many of the sources have been measured by source testing, the reliability of these emission rates has not been tested from a dispersion modeling perspective. This facility is a significant source of SO2 in the local region, making it critical that when modeling the emissions from this facility for regulatory or other purposes, that the resulting concentrations are representative of what would actually be measured or otherwise observed. To assess the accuracy of the modeling, a detailed analysis of modeled and monitored data for SO2 at the facility was performed. A mobile SO2 monitor sampled at five locations downwind of different source groups for different wind directions resulting in a total of 168 hr of valid data that could be used for the modeled to monitored results comparison. The facility was modeled in AERMOD (American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model) using site-specific meteorological data such that the modeled periods coincided with the same times as the monitored events. In addition, great effort was invested into estimating the actual SO2 emission rates that would likely be occurring during each of the monitoring events. SO2 concentrations were modeled for receptors around each monitoring location so that the modeled data could be directly compared with the monitored data. The modeled and monitored concentrations were compared and showed that there were no systematic biases in the modeled concentrations. Implications: This paper is a case study of a Combined Analysis of Modelled and Monitored Data (CAMM), which is an approach promulgated within air quality regulations in the Province of Ontario, Canada. Although combining dispersion models and monitoring data to estimate or refine estimates of source emission rates is not a new technique, this study shows how, with a high degree of rigor in the design of the monitoring and filtering of the data, it can be applied to a large industrial facility, with a variety of emission sources. The comparison of modeled and monitored SO2 concentrations in this case study also provides an illustration of the AERMOD model performance for a large industrial complex with many sources, at short time scales in comparison with monitored data. Overall, this analysis demonstrated that the AERMOD model performed well.

Correlations between metals in tree-rings of Prosopis julifora as indicators of sources of heavy metal contamination

Heavy-metals (Cu, Pb and Zn) in tree-ring sequences of Prosopis juliflora, a tree species native to arid environments, were analyzed by ICP-MS. The tree-ring sequences were obtained from three specimens growing in an urban area previously reported as contaminated by the activity of a Cu smelter facility. The metal found in highest concentration in the wood was Zn, with concentrations up to 120mg/kg and an enrichment factor up to 26; followed by Cu (up to 9.6mg/kg, enrichment factor up to 8.6) and Pb (up to 1.4mg/kg, enrichment factor up to 3). By assessing the correlation between different metal concentration trends, it was possible to infer two main pollution sources: vehicle traffic and Cu smelter emissions. Vehicle traffic is indicated by a correlation between Pb and Zn over time within individual trees, whereas contamination from the Cu-smelting facility is indicated by a correlation of Cu over time between trees. In tree A there was a significant within-tree correlation between Pb and Zn concentration trends (r=0.856, P<0.001), whereas Cu showed no correlation with the other metals. For tree B, there were no within-tree correlations between these metals, but when comparing the concentration–time trends between trees A and B, there was a significant correlation for Cu (r=0.768, P<0.01). The tree-ring sequence from tree C showed significant within-tree correlation for Cu:Zn (r=0.430, P<0.01) and for Pb:Zn (r=0.753, P<0.001). The highest enrichment values were found in tree A, located along the path of the growing-season dominant wind direction from the smelter facility, and not in the tree growing closer to the smelter (tree C), suggesting that the smelter’s emissions are dispersed to longer distances through the tall chimneys, attenuating the impact to the area directly closest to the smelter facility. It is concluded that Prosopis juliflora appears as a good bioindicator based on its metal accumulation capacity and lack of metal mobility among tree rings, thus providing information on the chronology and sources of heavy-metal pollution in urban and industrial areas.

납 동위원소를 이용한 안동호 퇴적물 중의 납 오염 기원

본 연구는 안동호 퇴적물 중의 납 오염 기원을 조사하기 위해 안동호 퇴적물, 안동호 유역의 토양, 광미퇴적물 및 아연제련시설의 부산물 중의 납 동위원소를 분석하고 국내 외 결과와 비교하였다. 안동호 퇴적물 중의 <TEX>$^{207}Pb/^{206}Pb$</TEX> 및 <TEX>$^{208}Pb/^{206}Pb$</TEX>는 <TEX>$0.827{\pm}0.004$</TEX> 및 <TEX>$2.041{\pm}0.015$</TEX>로서 광미퇴적물의 <TEX>$0.815{\pm}0.002$</TEX> 및 <TEX>$2.016{\pm}0.006$</TEX>와 유사한 값을 나타내었으며, 토양 중 <TEX>$^{207}Pb/^{206}Pb$</TEX> 및 <TEX>$^{208}Pb/^{206}Pb$</TEX>는 0.756~0.881 및 1.872~2.187로 퇴적물 및 광미퇴적물에 비해 넓은 범위의 납 동위원소 분포를 나타냈다. 아연 광석의 <TEX>$^{207}Pb/^{206}Pb$</TEX> 및 <TEX>$^{208}Pb/^{206}Pb$</TEX>는 0.816~0.956(평균 0.832), 2.029~2.219(평균 2.059)로서 비교적 넓은 범위의 동위원소 조성변화를 보였으며, 폐수 및 슬러지 중의 <TEX>$^{207}Pb/^{206}Pb$</TEX> 및 <TEX>$^{208}Pb/^{206}Pb$</TEX>는 0.883~0.905(평균 0.887), 2.127~2.156(평균 2.133)로 나타났다. 안동호 퇴적물은 연화광산의 광상과 유사한 납 동위원소 분포특성을 보였으며, 광미퇴적물과 토양에 의한 혼합 특성을, 아연제련시설의 경우, 캐나다 및 호주 등으로부터 수입된 아연 광석에 의한 납 동위원소 분포와 유사한 분포 특성을 나타냈다. The objective of this study was to identify Pb pollution sources of sediments in Lake Andong. We analysed Pb isotopes in sediments from Lake Andong, soils and mining tails from the watershed as well as sludges and wastewater from zinc smelting facilities which exists in upper stream of Lake Andong. The Pb isotope ratios (<TEX>$^{207}Pb/^{206}Pb$</TEX> and <TEX>$^{208}Pb/^{206}Pb$</TEX>) for sediments are <TEX>$0.827{\pm}0.004$</TEX> and <TEX>$2.041{\pm}0.015$</TEX>, which showed similar values with those of mining tails, <TEX>$0.815{\pm}0.002$</TEX> and <TEX>$2.016{\pm}0.006$</TEX>, respectively. The isotopic ratio values of soils existed in the range of 0.756~0.881 and 1.872~2.187. In imported zinc ores, the isotopic ratio values existed in the range of 0.816~0.956 (mean 0.832) and 2.029~2.219 (mean 2.059). These values were similar to those in zinc and lead concentrate originated from Canada and South America. Additionally, isotopic ratio values for sludge and wastewater were <TEX>$17.515{\pm}0.155$</TEX>, <TEX>$15.537{\pm}0.018$</TEX>, and <TEX>$37.357{\pm}0.173$</TEX>, respectively. The Pb isotopic ratio of sediments showed binary combination patterns with soil and mining tails, which were similar to those for Korean Pb ore.

Stability and leaching of cobalt smelter fly ash

The leaching behaviour of fly ash from a Co smelter situated in the Zambian Copperbelt was studied as a function of pH (5–12) using the pH-static leaching test (CEN/TS 14997). Various experimental time intervals (48h and 168h) were evaluated. The leaching results were combined with the ORCHESTRA modelling framework and a detailed mineralogical investigation was performed on the original FA and leached solid residues. The largest amounts of Co, Cu, Pb and Zn were leached at pH 5, generally with the lowest concentrations between pH 9 and 11 and slightly increased concentrations at pH 12. For most elements, the released concentrations were very similar after 48h and 168h, indicating near-equilibrium conditions in the system. Calcite, clinopyroxenes, quartz and amorphous phases predominated in the fly ash. Various metallic sulfides, alloys and the presence of Cu, Co and Zn in silicates and glass were detected using SEM/EDS and/or TEM/EDS. The leaching of metals was mainly attributed to the dissolution of metallic particles. Partial dissolution of silicate and glass fractions was assumed to significantly influence the release of Ca, Mg, Fe, K, Al and Si as well as Cu, Co and Zn. The formation of illite was suggested by the ORCHESTRA modelling to be one of the main solubility-controlling phases for major elements, whereas Co and Zn were controlled by CoO and zincite, respectively. Sorption of metals on hydrous ferric oxides was assumed to be an important attenuation mechanism, especially for the release of Pb and Cu. However, there is a high risk of Co, Cu, Pb and Zn mobility in the acidic soils around the smelter facility. Therefore, potential local options for “stabilisation” of the fly ash were evaluated on the basis of the modelling results using the PHREEQC code.

Mercury concentrations and mercury isotope composition in lake sediment cores from the vicinity of a metal smelting facility in Flin Flon, Manitoba

The Flin Flon copper–zinc smelter is a site of concern as it has been the largest single source of atmospheric mercury emissions in Canada. Variations in total mercury concentration and mercury isotopic composition were determined in three lake sediment cores at different distances from the Flin Flon smelter. Total mercury concentrations ranged from 90 to 19,000ng/g and were much higher in cores obtained closer to the smelter. The observed mass dependent mercury isotope fraction (MDF) varied significantly among sediment cores collected closer to the smelter (−0.67 to −1.48‰) and cores collected from further away (−1.44 to −2.71‰). Mass independent fraction (MIF) was detectable in some but not all samples (−0.05 to 0.14‰). A simple binary mixing model showed that mercury in all sediment samples investigated in this study originated in variable proportions from the Flin Flon smelter. The study demonstrated that mercury isotope ratio measurements could serve as an effective tool for tracing mercury contamination caused by atmospheric emissions from metal smelting activities.