Explore the vast range of titles available.

This paper presents a treatment process for copper smelter dust's chlorinated leaching solution. Addressing the challenge of separating As and valuable metals from this solution, the process utilized S02 to reduce As(V) to As(III) and NaOH to neutralize Bi(III), resulting in the stepwise formation of AS2O3 and BiOCl. The results indicate that, under optimal conditions, the precipitation ratio of As reached 71.23%, and the Bi precipitation ratio reached 98.38%. Following Bi precipitation, two separation strategies were attempted for the recovery of Cu and Zn. The first strategy involves recovery of Cu using a sulfide precipitation method, followed by the recrystallization of ZnS04. Under optimal conditions, the Cu precipitation ratio can reach 99.81%. The second strategy involves Cu solvent extraction using Lix984N coupled with Zn solvent extraction using P204. Under appropriate conditions, the Cu extraction rate can achieve 98.59%. A comprehensive assessment indicates that using sulfidation - crystallization to separate Cu and Zn is more economical than employing solvent extraction methods. Consequently, the final process is determined as follows: As removal by SO2 reduction > Bi recovery by NaOH neutralization > Cu recovery by sulfidation precipitation > Zn recovery by crystallization.

The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), since October 2004. The data products from the same instrument provide consistent spatial and temporal coverage and permit the study of anthropogenic and natural emissions on local-to-global scales. In this paper, we examine changes in SO2 and NO2 over some of the world's most polluted industrialized regions during the first decade of OMI observations. In terms of regional pollution changes, we see both upward and downward trends, sometimes in opposite directions for NO2 and SO2, for different study areas. The trends are, for the most part, associated with economic and/or technological changes in energy use, as well as regional regulatory policies. Over the eastern US, both NO2 and SO2 levels decreased dramatically from 2005 to 2015, by more than 40 and 80 percent, respectively, as a result of both technological improvements and stricter regulations of emissions. OMI confirmed large reductions in SO2 over eastern Europe's largest coal-fired power plants after installation of flue gas desulfurization devices. The North China Plain has the world's most severe SO2 pollution, but a decreasing trend has been observed since 2011, with about a 50 percent reduction in 2012-2015, due to an economic slowdown and government efforts to restrain emissions from the power and industrial sectors. In contrast, India's SO2 and NO2 levels from coal power plants and smelters are growing at a fast pace, increasing by more than 100 and 50 percent, respectively, from 2005 to 2015. Several SO2 hot spots observed over the Persian Gulf are probably related to oil and gas operations and indicate a possible underestimation of emissions from these sources in bottom-up emission inventories. Overall, OMI observations have proved valuable in documenting rapid changes in air quality over different parts of the world during last decade. The baseline established during the first 11 years of OMI is indispensable for the interpretation of air quality measurements from current and future satellite atmospheric composition missions.

The study’s main purpose is to investigate the complex interaction between innovation, renewable energy consumption, and CO 2 emissions (CO 2 e), under the Kuznets curve framework, for BRICS economies from 1980 to 2016. The empirical estimates drwan from the CCEMG technique highlighted the heterogeneous role of innovation. The results indicated that innovation activities have failed to disrupt CO 2 e in China, India, Russia, and South Africa, except for Brazil. Second, the data showed that renewable energy consumption has mitigated CO 2 e in the BRICS panel, Russia, India, and China, excluding South Africa. Third, the existence of the EKC hypothesis was confirmed in all the BRICS economies, excluding India and South Africa. Fourth, the causality estimations reflected a two-way causality between innovation and CO 2 e; innovation and GDP per capita; innovation and renewable energy consumption; and between CO 2 e and income, thereby confirming the acceptance of income-led emission hypothesis in for BRICS economies, and vice versa.

Metal(loid)s pose a significant hazard due to inherent toxicity. Individuals are particularly exposed to metal(loid)s in soil through direct or indirect contact. Identifying metal(loid) sources in soil is required for exposure mitigation to anthropogenic metal(loid)s, while metal(loid)s are natural constitutes of soil. Metal(loid) concentrations and Pb isotopes were determined in residential soil profiles impacted by a Zn smelter to distinguish the anthropogenic effect from natural levels. One hundred sixty-nine core soil samples were collected from depths down to 5.5 m below ground level at 19 sites and were divided into Zn-Cd-As- and As-contaminated groups based on the worrisome level (WL) of soil contamination. The Zn-Cd-As-contaminated group ( n  = 62) was observed at depths < 1 m, showed high Zn levels (mean of 1168 mg/kg) and Cd and As frequently exceeding WLs, and had low 206 Pb/ 207 Pb ratios close to the Zn smelter. In contrast, the As-contaminated group ( n  = 96) was observed at depths > 1 m, did not have other metals exceeding WLs, and showed a wide range of 206 Pb/ 207 Pb ratios far away from the Zn smelter. The results indicated that the pollution sources of Zn-Cd-As- and As-contaminated soils were fugitive dust emissions from smelter stacks and geology, respectively. The metal(loid)s in host rock set geochemical baselines in soil profiles, while smelting activities affected the upper layers over 50 years. This study demonstrated the effectiveness of utilizing the vertical distribution of metal(loid) concentrations and Pb isotopes in soil profiles for distinguishing between anthropogenic and geogenic origins, in combination with baseline assessment.

Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new principal component analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30ktyr-1 to more than 4000ktyr-1 of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297); smelters (53); and sources related to the oil and gas industry (65). The sources were identified using different methods, including through OMI measurements themselves applied to a new emission detection algorithm, and their evolution during the 2005-2014 period was traced by estimating annual emissions from each source. For volcanic sources, the study focused on continuous degassing, and emissions from explosive eruptions were excluded. Emissions from degassing volcanic sources were measured, many for the first time, and collectively they account for about 30% of total SO2 emissions estimated from OMI measurements, but that fraction has increased in recent years given that cumulative global emissions from power plants and smelters are declining while emissions from oil and gas industry remained nearly constant. Anthropogenic emissions from the USA declined by 80% over the 2005-2014 period as did emissions from western and central Europe, whereas emissions from India nearly doubled, and emissions from other large SO2-emitting regions (South Africa, Russia, Mexico, and the Middle East) remained fairly constant. In total, OMI-based estimates account for about a half of total reported anthropogenic SO2 emissions; the remaining half is likely related to sources emitting less than 30ktyr-1 and not detected by OMI.

The atmospheric Pb emissions (1901–2019), from one of the world’s largest non-ferrous metallurgical complexes (Met-Mex in Torreón, México), were estimated based on historical records of modifications in the design, processes, and production volumes. Eight historical periods, with differing amounts of Pb emissions, were distinguished: (1) Essentially no controls (1901–1960); (2) migration to limited controls (1961–1972) by conversion to a Pb-Zn smelter-refining complex and installation of SO 2 collectors in 1961–1963; (3) completion to limited control (1973–1977) by the installation of a third H 2 SO 4 collector and a low-efficiency filtration system; (4) maintenance of limited control with no changes (1978–1987); (5) migration to strict control (1988 to 1998) by updating H 2 SO 4 collectors and installation of fertilizer and SO 2 liquid extraction plants; (6) completion to strict control (1999–2000) by the installation of state-art technology filtration systems and roofing working areas; (7) migration to abatement (2001–2003) by implantation of good management practices; and (8) maintenance of abatement following good management practices (2004–2019). Based on differences between those periods, we reconstructed the evolution of the Pb emission reduction efficiency (ER in %) and Pb emission factors (EF in gram/ton) for the Torreón complex. Pb emitted by the complex over the past 118 years totaled 23,350–27,580 t, with most of it (63–75%) occurring when emission controls were negligible (pre-1960 period). In comparisons with other facilities worldwide (e.g., the USA, Canada, and Europa), the modification in Met-Mex for control the Pb emission occurred several years. Emissions from the primary Pb-Zn smelter-refining are released mostly to the atmosphere from the sintering, smelting, drossing, and refining. While Pb emissions from the facility have declined by over an order of magnitude to contemporary levels (≤ 12.6 t/year), the current Pb rates still account for atmospheric Pb levels that are 2–3 times higher the USEPA standard and still constitutes a major health threat in Torreón.

The EPA Positive Matrix Factorization (PMF) 5.0 model was applied to determine the sources and characteristics of PM10 collected near the copper smelter in Bor, Serbia, from September 2009 to July 2010. For a better understanding of the industrial sources of PM10 pollution, the dataset was divided into four observation periods: heating season (HS), non-heating season (NHS), copper smelter in work (SW), and copper smelter out of work (SOW). The daily limit for the PM10 fraction of 50 μg/m3 was exceeded on one-sixth of days in the NHS, about half the days in the HS, and about one-third of days during the SOW and SW period. The nine different sources of PM10 were identified: fuel combustion, industrial dust, dust from tailings, storage and preparation of raw materials, secondary nitrate, Cu smelter, traffic, cadmium, and plant for the production of precious metals. The contribution of factors related to the activities in the copper smelter complex to the total mass of PM10 was 83.1%. When the copper smelter was out of work the contribution of all the factors related to PM10 pollution from the copper smelter to the total mass of the PM10 was 2.3-fold lower, 35.8%, compared with the period when the copper smelter was in work. This study is the first attempt to use PMF receptor modeling to determine the air pollution sources and their contribution to ambient air pollution in the city of Bor, Serbia.

The cooling of the Earth’s climate through the effects of anthropogenic aerosols on clouds offsets an unknown fraction of greenhouse gas warming. An increase in the amount of water inside liquid-phase clouds induced by aerosols, through the suppression of rain formation, has been postulated to lead to substantial cooling, which would imply that the Earth’s surface temperature is highly sensitive to anthropogenic forcing. Here we provide direct observational evidence that, instead of a strong increase, aerosols cause a relatively weak average decrease in the amount of water in liquid-phase clouds compared with unpolluted clouds. Measurements of polluted clouds downwind of various anthropogenic sources—such as oil refineries, smelters, coal-fired power plants, cities, wildfires and ships—reveal that aerosol-induced cloud-water increases, caused by suppressed rain formation, and decreases, caused by enhanced evaporation of cloud water, partially cancel each other out. We estimate that the observed decrease in cloud water offsets 29% of the global climate-cooling effect caused by aerosol-induced increases in the concentration of cloud droplets. These findings invalidate the hypothesis that increases in cloud water cause a substantial climate cooling effect and translate into reduced uncertainty in projections of future climate. Satellite data for cloud tracks downwind of major pollution sources show a relatively small global average decrease in cloud water caused by anthropogenic aerosols, invalidating claims that aerosol-induced effects contribute substantially to climate cooling.

ObjectiveSummarize the framework for incorporating bias appraisal for observational epidemiology studies into evidence synthesis for cancer hazard identification, as recommended in the recently published IARC volume. Describe how bias assessment has been incorporated into recent Monographs evaluations.MethodsThe recommended framework for incorporating bias assessments into evidence synthesis focuses on identification of key biases among informative studies, including direction and (where possible) magnitude, assessing their impact on study estimates, and triangulating findings among studies with different sources of bias. Scenarios are described for situations with few vs. many informative studies. We examined use of the bias assessment approaches laid out in the book for confounding, information bias, and selection bias in Monographs Volumes 131–138 (evaluations conducted in 2022–2025).ResultsEach of the eight volumes considered has incorporated bias assessment tools into the evidence synthesis. For example, in an evaluation of antimony (Vol. 131), an assessment of bias resulting from co-exposure to arsenic among smelter workers led to a conclusion that arsenic could not entirely explain the observed lung cancer risk. In evaluations of occupational exposure as a firefighter (Vol. 132) and several pharmaceuticals (Vol. 137), meta-analyses stratified by major sources of bias were used in evidence triangulation. In the evaluation of PFOA (Vol. 135), information bias from single-timepoint exposure measurement was quantified using repeated-measurement data. For acrylonitrile (Vol. 136), externally conducted bias adjustment for healthy worker survivor bias was important for the determination of sufficient evidence for lung cancer.ConclusionsIncorporation of bias appraisal tools into evidence synthesis has strengthened recent IARC Monographs cancer hazard identification, giving tools to inform and complement Working Groups’ expert judgment.

Concentration data are reported for 18 trace elements in chalcopyrite from a suite of 53 samples from 15 different ore deposits obtained by laser-ablation inductively-coupled plasma-mass spectrometry. Chalcopyrite is demonstrated to host a wide range of trace elements including Mn, Co, Zn, Ga, Se, Ag, Cd, In, Sn, Sb, Hg, Tl, Pb and Bi. The concentration of some of these elements can be high (hundreds to thousands of ppm) but most are typically tens to hundreds of ppm. The ability of chalcopyrite to host trace elements generally increases in the absence of other co-crystallizing sulfides. In deposits in which the sulfide assemblage recrystallized during syn-metamorphic deformation, the concentrations of Sn and Ga in chalcopyrite will generally increase in the presence of co-recrystallizing sphalerite and/or galena, suggesting that chalcopyrite is the preferred host at higher temperatures and/or pressures. Trace-element concentrations in chalcopyrite typically show little variation at the sample scale, yet there is potential for significant variation between samples from any individual deposit. The Zn:Cd ratio in chalcopyrite shows some evidence of a systematic variation across the dataset, which depends, at least in part, on temperature of crystallization. Under constant physiochemical conditions the Cd:Zn ratios in co-crystallizing chalcopyrite and sphalerite are typically approximately equal. Any distinct difference in the Cd:Zn ratios in the two minerals, and/or a non-constant Cd:Zn ratio in chalcopyrite, may be an indication of varying physiochemical conditions during crystallization. Chalcopyrite is generally a poor host for most elements considered harmful or unwanted in the smelting of Cu, suggesting it is rarely a significant contributor to the overall content of such elements in copper concentrates. The exceptions are Se and Hg which may be sufficiently enriched in chalcopyrite to exceed statutory limits and thus incur monetary penalties from a smelter.