Assessment of internal exposure risk from metals pollution of occupational and non-occupational populations around a non-ferrous metal smelting plant.

Non-ferrous metal smelting poses significant risks to public health. Specifically, the copper smelting process releases arsenic, a semi-volatile metalloid, which poses an emerging exposure risk to both workers and nearby residents. To comprehensively understand the internal exposure risks of metal(loid)s from copper smelting, we explored eighteen metal(loid)s and arsenic metabolites in the urine of both occupational and non-occupational populations using inductively coupled plasma mass spectrometry with high-performance liquid chromatography and compared their health risks. Results showed that zinc and copper (485.38 and 14.00 µg/L), and arsenic, lead, cadmium, vanadium, tin and antimony (46.80, 6.82, 2.17, 0.40, 0.44 and 0.23 µg/L, respectively) in workers (n=179) were significantly higher compared to controls (n=168), while Zinc, tin and antimony (412.10, 0.51 and 0.15 µg/L, respectively) of residents were significantly higher than controls. Additionally, workers had a higher monomethyl arsenic percentage (MMA%), showing lower arsenic methylation capacity. Source appointment analysis identified arsenic, lead, cadmium, antimony, tin and thallium as co-exposure metal(loid)s from copper smelting, positively relating to the age of workers. The hazard index (HI) of workers exceeded 1.0, while residents and control were approximately at 1.0. Besides, all three populations had accumulated cancer risks exceeding 1.0 × 10-4, and arsenite (AsIII) was the main contributor to the variation of workers and residents. Furthermore, residents living closer to the smelting plant had higher health risks. This study reveals arsenic exposure metabolites and multiple metals as emerging contaminants for copper smelting exposure populations, providing valuable insights for pollution control in non-ferrous metal smelting.

Standardized framework for assessing soil quality at antimony smelting site by considering microbial-induced resilience and heavy metal contamination.

Antimony smelting activities damage the soil and vegetation surroundings while generating economic value. However, no standardized methods are available to diagnose the extent of soil degradation at antimony smelting sites. This study developed a standardized framework for assessing soil quality by considering microbial-induced resilience and heavy metal contamination at Xikuangshan antimony smelting site. The soil resilience index (SRI) and soil contamination index (SCI) were calculated by Minimum Data Set and geo-accumulation model, respectively. After standardized by a multi-criteria quantitative procedure of modified Nemerow's pollution index (NPI), the integrated assessment of soil quality index (SQI), which is the minimum of SRINPI and SCINPI, was achieved. The results showed that Sb and As were the prominent metal(loid) pollutants, and significant correlations between SQI and SRI indicated that the poor soil quality was mainly caused by the low level of soil resilience. The primary limiting factors of SRI were Fungi in high and middle contaminated areas, and Skermanella in low contaminated area, suggesting that the weak soil resilience was caused by low specific microbial abundances. Microbial regulation and phytoremediation are greatly required to improve the soil quality at antimony smelting sites from the perspectives of pollution control and resilience improvement. This study improves our understanding of ecological effects of antimony smelting sites and provides a theoretical basis for ecological restoration and sustainable development of mining areas.

Carbon emissions in China's steel industry from a life cycle perspective: Carbon footprint insights.

China is the most important steel producer in the world, and its steel industry is one of the most carbon-intensive industries in China. Consequently, research on carbon emissions from the steel industry is crucial for China to achieve carbon neutrality and meet its sustainable global development goals. We constructed a carbon dioxide (CO2) emission model for China's iron and steel industry from a life cycle perspective, conducted an empirical analysis based on data from 2019, and calculated the CO2 emissions of the industry throughout its life cycle. Key emission reduction factors were identified using sensitivity analysis. The results demonstrated that the CO2 emission intensity of the steel industry was 2.33 ton CO2/ton, and the production and manufacturing stages were the main sources of CO2 emissions, accounting for 89.84% of the total steel life-cycle emissions. Notably, fossil fuel combustion had the highest sensitivity to steel CO2 emissions, with a sensitivity coefficient of 0.68, reducing the amount of fossil fuel combustion by 20% and carbon emissions by 13.60%. The sensitivities of power structure optimization and scrap consumption were similar, while that of the transportation structure adjustment was the lowest, with a sensitivity coefficient of less than 0.1. Given the current strategic goals of peak carbon and carbon neutrality, it is in the best interest of the Chinese government to actively promote energy-saving and low-carbon technologies, increase the ratio of scrap steel to steelmaking, and build a new power system.

[Pollution Characteristics, Risk Assessment, and Source Analysis of Heavy Metals in Soil from a Typical Abandoned Antimony Smelting Factory].

Considering the surface soil （0-20 cm） from a typical abandoned antimony smelting factory area in Dachang Town, Qinglong County, Guizhou Province, as a case study, a total of 14 soil samples were systematically collected from both within and outside the smelting factory area. The analysis focused on the pollution status, distribution characteristics, and potential ecological risks of heavy metals such as Sb, As, Cd, Cr, Pb, Cu, Zn, Ni, and V in the soil. Additionally, an evaluation and analysis of pollution sources were conducted. The results showed that the mean concentrations of heavy metals including ω（Sb）, ω（As）, ω（Cd）, ω（Cr）, ω（Pb）, ω（Cu）, ω（Zn）, ω（Ni）, and ω（V） in the surface soil of the abandoned antimony smelting factory ranged from 4.58 to 15 049.33 mg·kg-1. With the exception of Cr and Ni, all values exceeded the background values of soils in Guizhou province. The single factor pollution indices of Sb and As were 83.61 and 7.01, respectively, indicating severe contamination. In contrast, Pb fell within the non-polluted to slightly polluted range. The comprehensive potential ecological risk of soil heavy metals was characterized by severe potential ecological risk levels for Sb, As, and Cd, while the remaining heavy metals fell within a range of moderate to substantial potential ecological risk levels. The assessment of the geoaccumulation index revealed that the soil in the study area was primarily contaminated by Sb and As, predominantly exhibiting contamination levels ranging from moderate to severe. The results from the RAC method suggested that Sb was the dominant focus for remediation in this abandoned smelting factory. The two primary pollutants, Sb and As, exhibited elevated levels in leachate toxicity, acid-soluble fraction, available fraction, gastric phase, and intestinal phase in terms of bioavailable content, indicating a certain potential hazard. Further, correlation analysis indicated a certain correlation between the total amount of heavy metals and leachate toxicity, available fraction, acid-soluble fraction, reducible fraction, oxidizable fraction, gastric phase extractable fraction, and intestinal phase extractable fraction. The APCS-MLR model indicated that the sources of Sb, As, Zn, Cu, and Cd were primarily industrial, while the sources of Cr and V were mainly natural, and Pb originated mainly from mixed sources.

Sensitivity analysis of human error in the steel industry: exploring the effects of psychosocial and mental health risk factors and burnout using Bayesian networks.

Introduction: Human error and the high rates of fatalities and other occupational accidents in the steel industry are of significant global relevance. The aim of this study was to investigate the effect of psychosocial, mental health, and burnout risk factors on human error probabilities in an industrial environment using Bayesian networks. Methods: This cross-sectional study was conducted in 2023. The participants were 252 employees of a steel company. Error probabilities related to the tasks of participants were estimated using the Human Error Assessment and Reduction Technique (HEART). Other data was collected using a survey that consisted of demographic information, the Maslach Burnout Inventory, Depression Anxiety Stress Scales, and a short version of the Copenhagen Psychosocial Questionnaire. A theoretical model was drawn in GeNIe academic software (version 2.3). Results: The results showed that all the studied variables were able to significantly affect the distribution of human error probabilities. Considering a distribution of 100% for the high state of these variables, the results showed that the greatest increases in error probability were related to two burnout dimensions: emotional exhaustion (29%) and depersonalization (28%). All the variables, with a probability of 100%, increased the probability of high human error probabilities by 46%. Conclusion: The most important variables in terms of their effect on human error probabilities were burnout dimensions, and these variables also had a mediation effect on the psychosocial and mental health variables. Therefore, preventive measures to control human error should first focus on managing the risks of burnout in workers. This, in turn, can also reduce the effect of psychosocial risk factors and mental health problems on human error in the workplace.

Sustainable quaternary binders made from metallurgical wastes of northeast Mexico: strength, hydration products, and durability.

In this research, four industrial wastes were used for up to 80% as supplementary cementitious materials (SCMs) in cement mortar systems: ground granulated blast furnace slag, electric arc furnace slag, basic oxygen furnace slag, and waste limestone powder. Quaternary cementitious blends were prepared and studied for up to 120 days. Workability, compressive strength, durability, microstructures, and sustainability studies were performed and compared with Portland cement references. Results showed that more than 30 MPa in compressive strength can be achieved by > 50% replacement with SCMs; only 9% below the reference. Neither H2SO4 nor MgSO4 attacks resulted in critical damages; nevertheless, curing under NaCl solution showed detrimental behavior. C-S-H with a low Ca/Si ratio was identified in the mortars as the main hydration product, possibly intermixed with stratlingite, C-A-S-H and/or hydrotalcite. Environmental impact for the blended cements was determined as the CO2eq. factor from a simple life cycle assessment. The embodied greenhouse gasses varied in 260.2-541.4 kg CO2eq./ton of binder depending on the formulation. This was 40-70% less than Portland cement (922.6 kg CO2eq./ton). The production of the raw materials dominated the polluting emissions, while freight, grinding, and sieving had little environmental impact.

Mechanical Properties, Microstructure, Degradation Behavior, and Biocompatibility of Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg Guided Bone Regeneration Barrier Membranes Prepared Using a Powder Metallurgy Method.

Pure zinc exhibits low mechanical properties, making it unsuitable for use in guided bone regeneration (GBR) membranes. The present study focused on the preparation of Zn alloy GBR films using powder metallurgy, resulting in Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR films. The tensile strength of the pure Zn GBR film measured 85.9 MPa, while an elongation at break was 13.5%. In contrast, Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR films demonstrated significantly higher tensile strengths of 145.3 and 164.4 MPa, respectively, whereas elongations at break were 30.2% and 19.3%. The addition of Ti, Fe, and Mg substantially enhanced the mechanical properties of the zinc alloys. Corrosion analysis revealed that Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR membranes exhibited corrosion potentials of -1.298 and -1.316 V, respectively, with corresponding corrosion current densities of 12.11 and 13.32 µA/cm2. These values were translated to corrosion rates of 0.181 and 0.199 mm/year, indicating faster corrosion rates compared to pure Zn GBR membranes, which displayed a corrosion rate of 0.108 mm/year. Notably, both Zn-based alloy GBR membranes demonstrated excellent cytocompatibility, with a cytotoxicity rating of 0-1 in 25% leachate. Additionally, these membranes exhibited favorable osteogenic ability, as evidenced by the quantitative bone volume/tissue volume ratios (BV/TV) of new bone formation, which reached 30.3 ± 1.4% and 65.5 ± 1.8% for the Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR membranes, respectively, after 12 weeks of implantation. These results highlighted the significant potential for facilitating new bone growth. The proposed Zn-0.5Ti-0.5Fe and Zn-0.5Ti-0.5Mg alloy GBR membranes showed promise as viable biodegradable materials for future clinical studies.

A systematic review of decarbonization pathway and modeling conception in iron and steel industry at micro-, meso-, and macro-levels.

To meet the carbon-neutral goal in 2050, an accelerated transition of decarbonization is needed in the iron and steel industry. Lots of decarbonization path models are recently being used to analyze the technology pathways, industrial structure adjustments, and short- or long-term policies for greenhouse gas emission reduction. Thus, systematic insight is required for better making sense of the status quo and differences in low-carbon transition pathways at different levels. This paper reviews the carbon emission reduction of steel production routes and summarizes the decarbonization models from micro-, meso-, and macro-level perspectives, respectively. First, we systematically analyze the capacity and potential of both available and emerging technologies in the iron and steel production process. Additionally, we conduct a theoretical analysis of the bottom-up models currently used as effective tools to assess decarbonization technology pathways. Subsequently, pathways and models in terms of industrial synergy are elaborated. Policy guidance and market support are explored to overcome the challenges of collaborative carbon reduction faced by global steel producers. The characteristics of top-down models for supporting carbon reduction are also discussed. Finally, gaps in the literature and future research agendas are identified. Advancing this research could enrich discussions on steel industry decarbonization and provide clearer assessments of modeling approaches. The results indicate that existing energy-saving technologies in the iron and steel industry have limited carbon reduction capacity. Significant reduction requires coordinated efforts with upstream and downstream industries, particularly in hydrogen and power sectors, along with financial support and favorable policies.

Bauxite mine and alumina refinery workers: mortality and cancer risk.

BACKGROUND: Aluminium industry workers are at risk of long-term health consequences. AIMS: To investigate mortality and cancer incidence in bauxite mine and alumina refinery workers. METHODS: A pre-existing cohort of workers was re-linked with the Australian National Death Index, and the Australian Cancer Database to provide additional death (7 years) and cancer (9 years) data. Standardized mortality ratios (SMRs) and standardized incidence rates (SIRs) were estimated by job category, duration of employment and time since first employment. RESULTS: Linkage was performed for 6935 (6207 male) workers. Compared with the general population, there was a reduced or similar risk of death for mine/refinery workers for all causes except mesothelioma which was increased amongst male production workers [SMR 2.42, 95% CI 1.11-4.60]. Mesothelioma incidence was also increased amongst males [SIR 2.50, 95% CI 1.60-3.71]. Male office workers had a greater incidence of prostate cancer [SIR 1.30, 95% CI 1.06-1.57] and thyroid cancer [SIR 3.47, 95% CI 1.66-6.38]. Melanoma incidence was increased in female office workers [SIR 2.27, 95% CI 1.36-3.54]. Lip cancer incidence was increased in male maintenance/production workers [SIR 2.04, 95% CI 1.02-3.65]. Overall cancer incidence was otherwise similar to the general Australian population. CONCLUSIONS: Overall risk of death and incidence of cancer for bauxite mine and alumina refinery workers was similar to the general population. Incidence and risk of death from mesothelioma were higher, likely due to historic asbestos exposure in this and other industries. The increased risk of melanoma, lip, prostate and thyroid cancers requires further investigation.

The prevalence of occupational injuries and associated risk factors among workers in iron and steel industries: a systematic review and meta-analysis.

BACKGROUND: The iron and steel industries are among the most dangerous workplaces in the world compared to other manufacturing industries. Workers are exposed to multiple occupational hazards, which predispose them to high risks of both fatal and non-fatal injuries. Currently, the data on the global prevalence and associated risk factors for occupational injuries in the iron and steel industries is fragmented and incomplete. This study was undertaken to address this issue by pooling data relating to the prevalence of occupational injuries and its associated factors among workers in iron and steel industries studies around the world. METHODS: The search was conducted systematically using PubMed, HINARI, EMBASE and Google Scholar for published studies in English that reported on occupational injuries and associated risk factors among workers in iron and steel industries. MetaXL version 5.3 software was used in the meta-analysis to estimate the pooled prevalence of occupational injuries and associated risk factors among workers in the iron and steel industries. The study protocol has been registered with PROSPERO, number CRD42022344258. RESULTS: Of the 447 articles identified, 15 studies from 9 countries met the inclusion criteria. The pooled prevalence estimate of occupational injury was 0.55 (95% CI: 0.15, 0.93). The pooled results indicated that the odds of having an occupational injury were 4.06 times higher among workers who did not use personal protective equipment compared to those who used such equipment. Likewise the odds of occupational injuries was increased by 1.65 among night shift workers compared to the counterpart. CONCLUSIONS: The global prevalence of occupational injuries in iron and steel industries was 55%. The results indicate that night work shift and the lack of use of personal protective equipment has a higher impact than other factors in the occurrence of occupational injuries in the iron and steel industries.

Fractionation and leaching of Cd, Cu, Fe, Pb, and Zn from smelter residues of an old environmental liability in Argentina.

An integrated chemical and mineralogical characterization approach was applied to smelter wastes collected from 50-year-old dump sites in Argentina. Characterization included pseudo-total element concentrations, acid generation/neutralization potential, sequential extractions, pH-dependent leaching kinetics, and mineralogical analysis of all residues. These analyses provided detailed information on the reactivity of the minerals in the waste material and associated metal release. Cadmium and Zn were the elements of greatest environmental concern due to their high mobility. On average, the release of Zn and Cd in pH-dependent leaching essays reached 17.6% (up to 5.24 mg g-1) and 52.7% (up to 0.02 mg g-1) of the pseudo-total content, respectively. Moreover, Cd and Zn were also the metals that showed the higher proportions of labile fractions associated to the adsorbed and exchangeable fraction (60-92% for Cd and 19-38% for Zn). Since Cd and Zn concentrations in the residue are not high enough to form their own minerals, a large proportion of these elements would be weakly adsorbed on Fe oxyhydroxides. In contrast, the low release of Cu, Pb and Fe would be associated with these elements being incorporated into the crystalline structure of insoluble or very poorly soluble minerals. Lead is incorporated into plumbojarosite and anglesite. Copper was mainly in association with Fe oxyhydroxides and may also have been incorporated into the plumbojarosite structure. The latter could act as a sink especially for Pb under the acidic conditions of the smelter residue. Despite the elevated concentrations of Pb observed in the residue, it showed a very low mobility (≈0.1%), indicating that it is mostly stabilized. Nevertheless, the smelter residue is a continuous source of metals requiring remediation.

Contribution assessment and accumulation prediction of heavy metals in wheat grain in a smelting-affected area using machine learning methods.

Due to the diverse controlling factors and their uneven spatial distribution, especially atmospheric deposition from smelters, assessing and predicting the accumulation of heavy metals (HM) in crops across smelting-affected areas becomes challenging. In this study, integrating HM influx from atmospheric deposition, a boosted regression tree model with an average R2 > 0.8 was obtained to predict accumulation of Pb, As, and Cd in wheat grain across a smelting region. The atmospheric deposition serves as the dominant factor influencing the accumulation of Pb (28.2 %) and As (31.2 %) in wheat grain, but shows a weak influence on Cd accumulation (12.1 %). The contents of available HM in soil affect HM accumulation in wheat grain more significantly than their total contents in soil with relative importance rates of Pb (14.4 % > 8.2 %), As (30.9 % > 4.0 %), and Cd (55.0 % > 16.9 %), respectively. Marginal effect analysis illustrates that HM accumulation in wheat grain begins to intensify when Pb content in atmospheric dust reaches 5140 mg/kg and available Cd content in soil exceeds 1.15 mg/kg. The path analysis rationalizes the cascading effects of distances from study sites to smelting factories on HM accumulation in wheat grain via negatively influencing atmospheric HM deposition. The study provides data support and a theoretical basis for the sustainable development of non-ferrous metal smelting industry, as well as for the restoration and risk management of HM-contaminated soils.

Machine vision-based detection of forbidden elements in the high-speed automatic scrap sorting line.

Highly efficient industrial sorting lines require fast and reliable classification methods. Various types of sensors are used to measure the features of an object to determine which output class it belongs to. One technique involves the use of an RGB camera and a machine learning classifier. The paper is focused on protecting the sorting process against prohibited and dangerous items potentially present in the sorted material that pose a threat to the sorting process or the subsequent metallurgical process. To achieve this, a convolutional neural network classifier was applied under real-life conditions to detect forbidden elements in copper-based metal scrap. A laboratory stand simulating the working conditions in a high-speed scrap sorting line was prepared. Using this custom stand, training and test sets for machine learning were gathered and labeled. An image preprocessing algorithm was designed to increase the robustness of the resulting forbidden element detector system. The performance of multiple neural network architectures and data set augmentations was analyzed. The highest accuracy of 98.03% and F1-score of 97.16% were achieved with a DenseNet-based classifier. The results of this paper show the feasibility of using the presented solution on a high-speed industrial line.

[On the June 25, 2024 Judgment of the Court of Justice of the European Union regarding Ilva Taranto (Southern Italy)]. / Sulla sentenza della Corte di Giustizia dell'Unione europea del 25 giugno 2024 in merito all'Ilva di Taranto.

The June 25, 2024 Judgment of the Court of Justice of the European Union is based on the Industrial Emissions (Integrated Pollution Prevention and Control) Directive 2010/75/EU and confirms its applicability to the Taranto steel plant, reiterating that the concept of pollution includes damage to the environment and human health; the health impact assessment of polluting industrial activities, such as the Ilva steelworks in Southern Italy, must constitute an internal act in the procedures for granting and reviewing the operating permission; all pollutants attributable to the plant that are scientifically recognized as harmful to health must be considered in the assessment procedures. In the case of serious and significant danger to the integrity of the environment and human health, the operation of the installation must be suspended. The Judgment highlights important elements on the level of principle and application, which are extraordinarily useful for environment and health personnel, for open-minded and aware local, regional, and national administrators, and above all for the citizens and communities most exposed to pollutants recognized as harmful to health. Preventive environmental health impact assessments gain renewed strength as tools for evaluative and authorized decision-making on production activities, in a sense of full integration between environment and health. The right to environmental and health protection and prevention is an integral part of the defence of human rights, especially in sacrifice zones such as Taranto and many other sites to be reclaimed, considered by the UN as "places where residents suffer devastating physical and mental health consequences and human rights violations".

Characterization of occupational inhalation exposures to particulate and gaseous straight and water-based metalworking fluids.

Exposure assessments to metalworking fluids (MWF) is difficult considering the complex nature of MWF. This study describes a comprehensive exposure assessment to straight and water-based MWFs among workers from 20 workshops. Metal and organic carbon (OC) content in new and used MWF were determined. Full-shift air samples of inhalable particulate and gaseous fraction were collected and analysed gravimetrically and for metals, OC, and aldehydes. Exposure determinants were ascertained through observations and interviews with workers. Determinants associated with personal inhalable particulate and gaseous fractions were systematically identified using mixed models. Similar inhalable particle exposure was observed for straight and water-based MWFs (64-386 µg/m3). The gaseous fraction was the most important contributor to the total mass fraction for both straight (322-2362 µg/m3) and water-based MWFs (101-699 µg/m3). The aerosolized particles exhibited low metal content irrespective of the MWF type; however, notable concentrations were observed in the sumps potentially reaching hazardous concentrations. Job activity clusters were important determinants for both exposure to particulate and gaseous fractions from straight MWF. Current machine enclosures remain an efficient determinant to reduce particulate MWF but were inefficient for the gaseous fraction. Properly managed water-based MWF meaning no recycling and no contamination from hydraulic fluids minimizes gaseous exposure. Workshop temperature also influenced the mass fractions. These findings suggest that exposures may be improved with control measures that reduce the gaseous fraction and proper management of MWF.

Chemodiversity of dissolved organic matter and its association with the bacterial community at a zinc smelting slag site after 10 years of direct revegetation.

Dissolved organic matter (DOM) plays a critical role in driving the development of biogeochemical functions in revegetated metal smelting slag sites, laying a fundamental basis for their sustainable rehabilitation. However, the DOM composition at the molecular level and its interaction with the microbial community in such sites undergoing long-term direct revegetation remain poorly understood. This study investigated the chemodiversity of DOM and its association with the bacterial community in the rhizosphere and non-rhizosphere slags of four plant species (Arundo donax, Broussonetia papyrifera, Cryptomeria fortunei, and Robinia pseudoacacia) planted at a zinc smelting slag site for 10 years. The results indicated that the relative abundance of lipids decreased from 18 % to 5 %, while the relative abundance of tannins and lignins/CRAM-like substances increased from 4 % to 10 % and from 44 % to 64 % in the revegetated slags, respectively. The chemical stability of the organic matter in the rhizosphere slag increased due to the retention of recalcitrant DOM components, such as lignins, aromatics, and tannins. As the diversity and relative abundance of the bacterial community increased, particularly within the Proteobacteria, there was better utilization of recalcitrant components (e.g., lignins/CRAM-like compounds), but this utilization was not invariable. In addition, potential preference associations between specific bacterial OTUs and DOM molecules were observed, possibly stimulated by heavy metal bioavailability. Network analysis revealed complex connectivity and strong interactions between the bacterial community and DOM molecules. These specific interactions between DOM molecules and the bacterial community enable adaptation to the harsh conditions of the slag environment. Overall, these findings provide novel insights into the transformation of DOM chemodiversity at the molecular level at a zinc smelting slag sites undergoing long-term revegetation. This knowledge could serve as a crucial foundation for developing direct revegetation strategies for the sustainable rehabilitation of metal smelting slag sites.

Metal concentrations in fish, crabs, and bivalve molluscs from marine waters adjacent to a multi-metals smelter and refinery.

Metal concentrations were determined in tissues of finfish, crabs, and bivalve molluscs collected from marine waters near Port Pirie, South Australia, the site of a long-standing multi-metals smelter and refinery. A general trend of tissue metal concentrations in order of highest to lowest was observed in bivalves > crabs > finfish. A lead concentration of 158 ± 6.6 mg/kg (wet wt.) was observed in blue mussels (Mytilus galloprovincialis) sampled close to the smelter. Lead concentrations correlated positively with proximity to the smelter in all biota analysed. Similar relationships were observed for cadmium, copper, zinc and selenium in all biota except razorfish (Pinna bicolor; Bivalvia: Pinnidae), which showed no correlation with proximity to the smelter for these metals. Inorganic arsenic concentrations were below the limit of reporting in the majority of the analysed samples, however inorganic arsenic concentrations in blue swimmer crabs (Portunus armatus) and blue mussels correlated with proximity to the smelter. Mercury concentrations in the biota analysed were generally low and showed variable relationships with proximity to the smelter, with no significant correlation observed in finfish and razorfish, a significant positive correlation in blue mussels, and a significant negative correlation in blue swimmer crabs. This is the first major study of metal concentrations in recreationally-targeted marine species near Port Pirie species for more than two decades. Comparison with data from previous studies conducted shows little change in tissue metal concentrations in marine biota near Port Pirie over the past 40 years.

Trends in sedimentary Cladocera and metal(loid)s from Williams Lake (Washington, USA) track ∼125 years of trans-boundary contamination from smelter emissions in the upper Columbia River valley.

The lead­zinc smelter at Trail (British Columbia, Canada) has operated continuously for ∼125 years, with long-standing concerns that transboundary metal(loid) and sulphur emissions have contaminated water bodies in both western Canada and Washington (WA), USA. To assess aquatic ecosystems affected by over a century of industrial contamination requires an understanding of pre-smelting conditions. Here, we use a dated sediment core from Williams Lake (WA), downwind of both the Trail and the short-lived LeRoi (Northport, WA) smelters, to track regional contaminant history and other environmental stressors. Specifically, we examine a selection of chemical elements, cladoceran assemblages, visible range spectroscopy-inferred chlorophyll a (VRS-Chl a) and visible near-infrared spectroscopy-inferred lake-water total organic carbon (VNIRS-TOC). Sedimentary proxies recorded the onset of smelting in 1896 CE, peak periods of aerial emissions in the early to mid-20th century, and the history of emission controls. With a few exceptions, sedimentary metal(loid)s exceeded Canadian Interim Sediment Quality Guidelines during the height of the smelting era and have declined substantially since ca. 2000 CE. The loss of metal-sensitive Cladocera and declines in primary production (VRS-Chl a) at the onset of the regional smelting era indicate a strong biological response to airborne industrial contamination. The largest cladoceran change in the sediment record was concurrent with accelerated mitigation efforts at the Trail facilities following the 1960s; however, this compositional shift was between ecologically similar daphniid taxa. Steep declines in VNIRS-TOC concentrations during the period of peak emissions at Trail suggested an increase in sulphur deposition on the landscape that reduced terrestrial carbon supply. However, the persistence of calcium-sensitive daphniids throughout the record indicates that alkaline Williams Lake had not acidified. Current cladoceran assemblages remain substantially distinct from pre-industrial communities, demonstrating how paleoecotoxicological approaches can be used to track the effects of multiple stressors in a temporally appropriate context.

Deep-sea microorganisms-driven V5+ and Cd2+ removal from vanadium smelting wastewater: Bacterial screening, performance and mechanism.

The disorderly discharge of industrial wastewater containing heavy metals has caused serious water pollution and ecological environmental risks, ultimately threatening human life and health. Biological treatment methods have obvious advantages, but the existing microorganisms exhibit issues such as poor resistance, adaptability, colonization ability, and low activity. However, a wide variety of microorganisms in deep-sea hydrothermal vent areas are tolerant to heavy metals, possessing the potential for efficient treatment of heavy metal wastewater. Based on this, the study obtained a group of deep-sea microbial communities dominated by Burkholderia-Caballeronia-Paraburkholderia through shake flask experiments from the sediments of deep-sea hydrothermal vents, which can simultaneously achieve the synchronous removal of vanadium and cadmium heavy metals through bioreduction, biosorption, and biomineralization. Through SEM-EDS, XRD, XPS, and FT-IR analyses, it was found that V(V) was reduced to V(IV) through a reduction process and subsequently precipitated. Glucose oxidation accelerated this process. Cd(II) underwent biomineralization to form precipitates such as cadmium hydroxide and cadmium carbonate. Functional groups on the microbial cell surface, such as -CH2, C=O, N-H, -COOH, phosphate groups, amino groups, and M-O moieties, participated in the bioadsorption processes of V(V) and Cd(II) heavy metals. Under optimal conditions, namely a temperature of 40 °C, pH value of 7.5, inoculation amount of 10%, salinity of 4%, COD concentration of 600 mg/L, V5+ concentration of 300 mg/L, and Cd2+ concentration of 40 mg/L, the OD600 can reach its highest at 72 h, with the removal efficiency of V5+, Cd2+, and COD in simulated vanadium smelting wastewater reaching 86.32%, 59.13%, and 61.63%, respectively. This study provides theoretical insights and practical evidence for understanding the dynamic changes in microbial community structure under heavy metal stress, as well as the resistance mechanisms of microbial treatment of industrial heavy metal wastewater.

The influence of chlorination additives on metal separation during the pyrometallurgical recovery of spent lithium-ion batteries.

The difficulty of separating Li during pyrometallurgical smelting of spent lithium-ion batteries (LIBs) has limited the development of pyrometallurgical processes. Chlorination enables the conversion of Li from spent LIBs to the gas phase during the smelting process. In this paper, the effects of four solid chlorinating agents (KCl, NaCl, CaCl2 and MgCl2) on Li volatilization and metal (Co, Cu, Ni and Fe) recovery were investigated. The four solid chlorinating agents were systematically compared in terms of the direct chlorination capacities, indirect chlorination capacities, alloy physical losses and chemical losses in the slag. CaCl2 was better suited for use as a solid chlorinating agent to promote Li volatilization due to its excellent results in these indexes. The temperature required for the release of HCl from MgCl2, facilitated by CO2 and SiO2, was lower than 500 °C. The prematurely released HCl failed to participate in the chlorination reaction. This resulted in approximately 12 % less Li volatilization when MgCl2 was used as a chlorinating agent compared to when CaCl2 was used. In addition, the use of KCl as a chlorinating agent decreased the chemical dissolution loss of alloys in the slag. The performance of NaCl was mediocre. Finally, based on evaluations of the four indexes, recommendations for the selection and optimization of solid chlorinating agents were provided.