Nonferrous Metal Mining Research Articles

Epidemiological Characteristics and Drug Resistance of Microbial Pathogens of Patients With Silicosis Combined With Pulmonary Infection

To investigate the epidemiological characteristics of patients with silicosis combined with pulmonary infection in recent years, to study the distribution and the drug susceptibility of fungal and bacterial pathogens in their sputum samples, and to provide references for the prevention and treatment of silicosis and the appropriate drug use. The clinical data and drug sensitivity test results of patients with silicosis combined with pulmonary infection diagnosed at the Department of Occupational Diseases, West China Fourth Hospital, Sichuan University were retrospectively analyzed. A total of 318 patients with silicosis combined with pulmonary infection who received treatment between January 2017 and December 2020 were enrolled. All the patients had positive microorganism test results. All participants were male. Their median age at the time of onset was 51.00 years and the median time of exposure to silica dust at work was 12.40 years. They worked mostly in construction, non-ferrous metal mining, and coal mining. The main types of work they did were pneumatic drilling, coal digging, and mining. The positive detection rates for the first, second and third phases of silicosis were 27.54%, 28.32%, and 32.97%, respectively. A total of 341 strains of fungal and bacterial pathogens were isolated, of which, 54.1% were fungi, including 114 strains (35.8%) of Candida albicans, and 53.1% were bacteria, including 168 strains (52.8%) of gram-negative bacteria, most of which being Klebsiella pneumoniae (30.2%). There was only 1 strain (0.3%) of gram-positive bacteria, namely Staphylococcus hemolyticus. Gram-negative bacilli were most resistant to ampicillin and highly sensitive to penicillin G and ofloxacin. Among patients with silicosis combined with pulmonary infection, the incidence of pulmonary infection increases along with the progress of silicosis. Microorganism analysis reveals high detection rates for fungi and the bacteria detected are predominantly gram-negative bacteria. The overall prospect for drug resistance rate was not optimistic.

Quantifying ecological and human health risks of metal(loid)s pollution from non-ferrous metal mining and smelting activities in Southwest China

The environmental release and transfer of heavy metal(loids) from natural and anthropogenic sources to neighboring habitats can pose an ecological threat to the exposed biota and habitat, as well as a human health risk to the residents. However, analytical tools to identify the potential contamination source(s) and assess the impact of this transfer have not been well described. Soil samples were collected from affected areas proximal to non-ferrous metal(loid)s mining and smelting facilities. Two integrated assessment methods, based on soil total metal(loid) content, included: (1) the potential ecological risk index combined with positive matrix factorization (PMF) and (2) human health risk assessment combined with PMF. Results indicated that there were four generic sources of pollution (based on PMF analyses of 115 replicated samples collected from four study areas): agricultural and industrial activities, traffic emissions, and natural sources. For ecological risk, the contribution of these metal(loid)s pollution sources were industrial activities (20.34–70.76 %), traffic emissions (18.73–56.93 %), natural sources (3.69–27.02 %), and agricultural activities (3.79–21.43 %). Health risks were higher for children than for adults. Industrial activity was a major source of non-carcinogenic risk to children (32.10–74.62 %) and adults (31.33–73.78 %), and carcinogenic risk to children (22.53–67.27 %) and adults (20.69–64.76 %). Total metal analysis indicated that As and Cd were highly enriched in the soil, but chemical fractionation revealed low As mobility. Total Cd and possibly As were the main pollutants causing the ecological risks at these contaminated sites. This study demonstrates that ecological and human health risks could be quantified to prioritize the pollution sources for reasonable contaminated site risk management.

Contributions of ectomycorrhizal fungi in a reclaimed poplar forest (Populus yunnanensis) in an abandoned metal mine tailings pond, southwest China

Reclamation using fast-growing trees has great potential for agroforestry development on former non-ferrous metal mining areas. However, the functional traits of ectomycorrhizal fungi (ECMF) and the relationship between ECMF and reclaimed trees remain unknown. Here, the restoration of ECMF and their functions in reclaimed poplar (Populus yunnanensis) growing in a derelict metal mine tailings pond were investigated. We identified ECMF belonging to 15 genera in 8 families, suggesting the occurrence of spontaneous diversification as poplar reclamation progressed. We described a previously unknown ectomycorrhizal relationship between poplar roots and Bovista limosa. Our results showed that B. limosa PY5 alleviated the phytotoxicity of Cd and enhanced poplar heavy metal tolerance, resulting in increased plant growth due to reduced Cd accumulation in host tissues. As part of the improved metal tolerance mechanism, PY5 colonization activated antioxidant systems, enhanced the conversion of Cd into inactive chemical forms, and promoted the compartmentalization of Cd into host cell walls. These results suggest that introducing adaptative ECMF may be an alternative to bioaugmenting reforestation and phytomanagement programs of fast-growing native trees in the barren metal mining and smelting areas.

Spatial-temporal variability and influence factors of Cd in soils of Guangxi, China.

In this study, the regional spatial-temporal variability of cadmium (Cd) in the topsoil of Guangxi, China from 2010 to 2016 was studied from data obtained from the China Geochemical Baseline Project (CGB Ⅰ and CGB Ⅱ). The driving forces of natural and anthropogenic variables were quantitatively analyzed using a geographically and temporally weighted regression model. The results showed that 1) soil Cd was highly enriched in 2010 and in soils of Hechi city in northwest Guangxi, a non-ferrous metal mining and metallurgy area, ~17% of the samples exceeded the soil contamination risk limit. In contrast, in 2016, the topsoil Cd content decreased significantly, with 7% of sites exceeding the soil risk limit. 2) Multiple factors jointly influenced the regional spatial variability of Cd. pH and organic carbon were found to be the main factors influencing Cd content and were strongly spatially correlated with Cd. Anthropogenic activities, including mining and industrial emissions, resulted in significant Cd enrichment in local areas, whereas agricultural and domestic pollutants were relatively weakly correlated with Cd. The weathering products of carbonates were significantly enriched in Cd; thus, the geological background played a significant role in the spatial variability of Cd. Soil-forming factors, including temperature, precipitation, and elevation influenced the spatial distribution of Cd, especially in the Cd background area. 3) Anthropogenic activities were the key factors influencing temporal changes in Cd. Mining caused significant enrichment of Cd in CGB Ⅰ, while industrial emissions were the primary factor for Cd enrichment in CGB Ⅱ. In addition, natural factors also played an important role; the increased Normalized Difference Vegetation Index suggested reduced desertification and reduction of soil erosion in the watershed and in pollutants transported from upstream.

Characteristics and Planting Safety Assessment of As Content in Dryland Soil and Maize in Guizhou Province

In order to understand the distribution characteristics of As content in dryland soils and maize seeds in Guizhou province and to evaluate the safety of maize cultivation, 468 natural soil samples, 1260 dryland surface soil samples, and 980 corresponding maize seed samples were systematically collected to determine their As content and basic physicochemical properties. The degree of contamination of the samples was evaluated by using the single-factor contamination index method. The results showed that: ① the range of ω(As) in dryland soil was 0.35-758.53 mg·kg-1, with a geometric mean of 23.28 mg·kg-1. The independent sample T-test showed that the As content of dryland soil in Guizhou province was significantly higher than that of natural soil ω(As) 21.29 mg·kg-1 (P<0.01), indicating the existence of arsenic accumulation effects in dryland soil; compared with the screening value of the "Agricultural Land Soil Pollution Risk Management and Control Standard" (GB 15618-2018), the excess rate of soil samples was 33.81%. ② Corn seed ω(As) ranged from 0.001 to 0.868 mg·kg-1, with a mean value of 0.064 mg·kg-1, and 0.61% of the corn seed samples exceeded the limit value of "Limits of Contaminants in Foods" (GB 2762-2017), with the exceeding points distributed in Bijie City, Qianxinan Prefecture, and Tongren City. ③ When corn seeds were used as feed and grain, maize could be safely grown in dryland soils in Guizhou province. This study showed that the soil As pollution in the dryland of Guizhou province was relatively serious, and overall safe maize cultivation can be achieved; however, the cultivation of maize around the As-related non-ferrous metal mining areas is still of concern.

Mercury contamination in the water and sediments of a typical inland river – Lake basin in China: Occurrence, sources, migration and risk assessment

In the area affected by non-ferrous metal mining activities, mercury (Hg) contamination in the water and sediments posed potential risks to ecology and human health. In this study, river water and sediment samples were collected in the Zijiang river - South Dongting Lake basin to analyze Hg residues, identify potential Hg sources and evaluate the ecological and health risks posed by Hg contamination. In this study, the average concentrations of THg, PHg, DHg and DMeHg in river water were 38.05 ± 27.13 ng/L, 25.18 ± 26.83 ng/L, 12.88 ± 9.64 ng/L and 0.29 ± 0.07 ng/L, respectively. The THg and MeHg contents in sediments were 234.24 ± 152.93 µg/kg and 0.48 ± 0.16 µg/kg, respectively. The more enrichment of Hg in sediments was observed in the Zijiang River than in the South Dongting Lake, especially in the upstream and midstream regions. Two potential Hg sources in the basin were identified by correlation matrix, principal component analysis (PCA) and positive matrix factorization (PMF) model. The comparable Hg flux with other rivers worldwide was found in the Zijiang River (0.53 Mg/y). Furthermore, it was found by the delayed geochemical hazard (DGH) model that the ecological risk of Hg was more significant in the Zijiang River with more frequent transformation pathways. For different populations, the health risk values caused by Hg were all lower than the USEPA’s guideline value. This study provided sound evidence for further control of Hg contamination.

Measuring capacity utilization under the constraints of energy consumption and CO2 emissions using meta-frontier DEA: A case of China's non-ferrous metal industries

Currently, China's non-ferrous metal industry (NMI) still has the problem of overcapacity, measuring its capacity utilization (CU) and revealing its determinants is an important way to resolve the overcapacity problem of China's NMI. Using the panel data of China's 29 NMIs, this paper constructs a meta-frontier data envelopment analysis (DEA) to measure CU by taking into account the energy consumption and CO2 emissions constraints, and decompose the CU into four parts: technical efficiency, technology gap, scale efficiency, and equipment utilization. The main findings indicate that during the period of 2004–2017, the CU of China's NMI is generally low. Non-ferrous metal alloy manufacturing and rolling processing has the highest CU, while non-ferrous metals mining and dressing shows the lowest CU. From the dynamic perspective, mining and dressing experienced CU decrease, while other two sub-industries achieved CU increase. Technical inefficiency and technology gap enlargement are two main barriers of China's NMIs' CU. Besides, among 29 NMIs, there are only ten industries witnessed a CU improvement, while the remaining nineteen industries all experienced decrease of CU. CU and its determinants across China's 29 NMIs are quite different. Thus, the policies to improve CU should be made tailored to each industry's features.

Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters

The effect of varying process parameters during bio-catalyzed leaching of metals from end-of-life printed circuit boards (PCBs) was investigated. Fragmented PCBs (under 2 mm) were subjected to an indirect bioleaching in a stirred tank reactor while pulp density, pH and initial ferric iron content were varied. An iron oxidizing Acidithiobacillus ferrooxidans 61 microbial strain was used to generate the lixiviant through oxidizing Fe(II) to Fe(III). Chemically generated Fe(III) was tested as lixiviant under the same conditions as the biological one for comparative purposes. Cell enumeration during leaching and microscopic observations of the input and leached PCBs were conducted in parallel to shed light on the observed phenomena. The degree of bringing metals in solution was found to depend mainly on ferric iron concentration and pH. For the entire duration being always kept as 24 h, substantial portion of Cu (~87%) was extracted respectively at 1% pulp density (PD), 15.5 g/L Fe3+ and pH 1. For Zn and Ni, nearly 100% recovery was observed at 5% PD, 18 g/L Fe3+ and pH 1.1. The achieved results offer possibilities for further studies at higher pulp density, to ultimately render the bioleaching approach as enabling economical and environmentally friendly technology for urban mining of non-ferrous metals.

Occupational health risk assessment of silicosis caused by silica dust exposure in non-ferrous metal mines in 7 provinces from 2019 to 2020

To explore the occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises. Using typical sampling method, 44 non-ferrous metal mining enterprises were selected in seven provinces.37 non-ferrous metal mining enterprises were included, and most of them were underground enterprises(97.30%). Enterprises basic information and silica dust exposure data of key positions were collected by using on-site hygiene investigation and detecting method. Finally, the International Council on Mining and Metals&apos;(ICMM) risk rating table method and occupational hazard risk index method(INDEX) were used to analyze the occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mines from total and respirable dust views, respectively. Meanwhile, the square weighted Kappa test was performed to analyze the consistency between two risk assessment method. Medium enterprises(64.69%(40.38%, 73.41%)), silver mining enterprises(84.69%(63.38%, 86.06%)) and antimony mining enterprises(72.22%) had relatively higher silica dust exposure rates. On-site hygiene detecting result showed that:(1) M(P25, P75) of free silica content was 21.18%(17.03%, 30.47%). (2) 1.60(0.86, 2.46)mg/m~3 for total dust concentration, 64.47% total dust concentration samples exceeding Chinese permissible concentration-time weighted average(PC-TWA), 0.68(0.30, 1.18) mg/m~3 for respiratory dust concentration, 50.00% respirable dust concentration samples exceeding Chinese PC-TWA. (3) Medium-sized enterprises, as well as rock drillers and crushers, had higher levels of silica dust exposure. Occupational health risk assessment result showed that:(1) The overall occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises was medium:(1) In term of total dust, ICMM risk rating table method and INDEX method indicated high and medium risks, respectively(S_(weighted) were 3.52 and 2.79). (2) In term of respirable dust, both ICMM risk rating table and INDEX method indicated medium risks(S_(weighted) were 2.78 and 2.35). (2) Medium-sized enterprises risk level was higher than other two production scales enterprises. ICMM risk rating table method and the INDEX method consistency analyses showed that these two risk assessment method had strong consistencies in terms of total dust or respirable dust(both Kappa values ≥ 0.600). The overall occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises was medium, and the risk levels of medium production-scale mining enterprises, rock driller and crusher were higher.

Hazard Classification and Stability Analysis of High and Steep Slopes from Underground to Open-Pit Mining.

The stability of high and steep slopes in open-pit mines is closely related to the mine operations and the lives of the surrounding residents, so it is important to ensure the safety and stability of the slopes. Hazard classification and stability analysis of high and steep slopes under different working conditions are studied using the Shizhuyuan non-ferrous metal mine from underground to open-pit mining as a typical example. Firstly, data on rock mechanics parameters were obtained through site investigation and sampling. Then, the slope model of the open-pit mine was established and some slopes were selected in the model for qualitative and quantitative analysis. The strength reduction method and the limit equilibrium method were used to calculate the safety factor under each working condition and point out the potential instability areas. The results show that the selected slopes are safe and stable under all working conditions. Finally, on the premise of maintaining the safety and stability of the mine, the final slope angle was optimized from the original 45°21′35″ to 55°30′41″ to reduce production costs and increase mining efficiency. The final open-pit boundary that meets the stability requirements was eventually obtained.

Comprehensive assessment of environmental and health risks of metal(loid)s pollution from non-ferrous metal mining and smelting activities

Abandoned non-ferrous metal mining and smelting sites have left a degraded environmental legacy, threatening the ecosystem and human health, particularly by the presence of As, Cd, Pb, and Cu as major contaminants. The health of the metal-contaminated soils was assessed by combining physicochemical parameters and microbial metabolism activity analyses. Low microbial metabolic activity indicated that soil microorganisms were inhibited by the presence of heavy metals. The content and speciation distribution of metals were closely linked to the measured microbial metabolic indicators. The invertase (INV) activity and peak time (Tpeak) were identified as sensitive bio-indicators for assessing soil health conditions. Combination environmental assessment (CEA) pollution, considering the total content and chemical form of metal(loid)s, revealed Cd, As, Pb, and Cu all reached high pollution degrees at the surrounding area, while Cr, Mn, Sb, Zn, Ni, and V were low pollution degrees. Different research sites ranked by potential ecological risk index (RI) as follows Pollution site (24621.22) > East site (19330.32) > West site (12989.49) > South site (9281.05), while different sites were sorted in reverse order by microbial indicators. The analyses revealed that the main human health risk was linked to As, threatening the local population with non-carcinogenic and carcinogenic hazards, particularly for children.

Contamination Assessment and Source Apportionment of Soil Heavy Metals in Typical Villages and Towns in a Nonferrous Metal Mining City

To investigate the soil contamination degree and potential ecological risk level of heavy metals in villages and towns in Tongling City, we collected 67 surface soil samples (including surface dusts and river sediments) from the typical districts, namely Shun'an Town, Zhongming Town, and Yi'an Economic Development Zone, and measured the contents of heavy metals including Cu, Zn, Pb, Cr, Cd, As, and Ni. Then, spatial distribution characteristics of heavy metals were analyzed, and their contamination degree and potential ecological risk were assessed. Finally, source apportionment of soil heavy metals was conducted using factor analysis. The results showed that the soil pH was weakly acidic in the study area, and the average contents of Cu, Zn, Cr, Cd, As, and Ni were 4.94, 2.89, 2.07, 0.94, 7.97, 4.03, and 2.02 times their soil background values in Tongling City, respectively. In general, the contents of soil heavy metals in the western part were higher than those in the eastern part across the studied area. According to the Nemerow pollution index, Cu, Cd, As, and Pb reached pollution levels; Zn, and Ni approached moderate pollution levels; and Cr belonged to the no pollution degree category. The Nemerow comprehensive pollution index of different land types was arranged in the order of river bed>town district>industrial land>vegetable land>agricultural land>mountain forest>village. On the whole, the contamination degree of soil heavy metals in the study area reached severe pollution levels. The order of potential ecological risk coefficients of soil heavy metals was Cd>As>Cu>Pb>Ni>Zn>Cr, in which Cd belonged to the extremely high risk level, Cu and As belonged to the medium risk level, and the others were all low risk levels. The potential ecological risk levels corresponding to different land types were as follows:river bed>town distribution>industrial land>vegetable land>agricultural land>village>mountain forest. The industrial land, vegetable land, and town district generally reached a very high risk level, and the agricultural land reached a high risk, whereas both village and mountain forest land showed a medium risk. Principal component analysis showed that Cu, Zn, Pb, Cd, and As in the study area were derived from local metal mining pollution; Cr was from both the geological background and metal mining pollution; and Ni mainly came from fossil fuel combustion.

Lability, bioaccessibility, and ecological and health risks of anthropogenic toxic heavy metals in the arid calcareous soil around a nonferrous metal smelting area

Lability and bioaccessibility of anthropogenic toxic heavy metals in arid calcareous soils are critical to understand their ecological and health risks. This study examined toxic heavy metal speciation in the calcareous soil contaminated by nonferrous metal smelting. Results demonstrated that approximately 70 years’ nonferrous metal smelting and mining in Baiyin led to significant contamination of nearby soil down to about 200 cm depth by cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn), with more serious contamination in the downwind areas of smelting or mining. More than half of Cd, Cu, Pb, and Zn in the soil was present in the labile fractions while more than 75% of cobalt (Co), chromium (Cr), nickel (Ni), and vanadium (V) was present in the residual fraction. Carbonate minerals in this calcareous soil play an important role in the labile fractions, with approximate 25% of Cd and Pb and 15% of Cu and Zn bound in carbonates. Bioaccessible Cd, Cu, Pb, and Zn in the soil were approximately 49.8%, 29.4%, 12.2%, and 33.8% in gastric phase and 13.5%, 15.9%, 4.3%, and 9.1% in intestinal phase of their total concentrations, respectively. Therefore, Cd and Zn were removed from gastric solution to a greater extent than Cu and Pb by neutral intestine environment. However, bioaccessible Co, Cr, Ni, and V in the soil were less than 3% of their total concentrations. Bioaccessibility of these metals but Cu in this calcareous soil was significantly lower than that for the acidic Ultisols and Alfisols in U.S. The concentrations of Cd, Cu, Pb, Zn, and Ni in each chemical and bioaccessible forms were significantly correlated linearly with their total concentrations in the calcareous soil, while only residual concentration was significantly correlated with the total concentration for Co, Cr, and V. These linear slopes showed that relative lability and bioaccessibility increased for Cd, but decreased for Cu, Pb, and Zn with the increase in their total concentrations in the calcareous soil. Direct oral soil ingestion would not pose a non-carcinogenic health risk to local children. However, very high potential ecological risk would be caused by these metals in the soil. These results provide improved insights into the biogeochemical processes of anthropogenic toxic heavy metals in the arid calcareous soils worldwide.

Study of the Effects on Mn, Pb, and Zn Solidification in Soil by a Mixed Curing Agent of Modified Diatomite.

In order to improve the application scale of diatomite in the remediation of heavy metal-contaminated soil in non-ferrous metal mining areas, the preparation of the modified diatomite-combined curing agent and its stabilizing effect on manganese (Mn), lead (Pb), and zinc (Zn) were systematically studied in non-ferrous metal tailing soil in this paper. The results showed that compared with that in natural diatomite (DE), the contents of available Mn in soil treated by acid- and alkali-modified diatomite samples (C-D and Na-D) were 18.82 and 25.93% lower, respectively, and the content of available Zn in Na-D was significantly lower, 6.71%, than that in DE. Further research showed that modified diatomite combined with quicklime (CaO) and hydroxyapatite (HAP) could significantly improve the solidification effect of soil heavy metals. Compared with that in single modified diatomite, the contents of available Mn, Pb, and Zn in the mixed curing agent-treated soil decreased by 23.59–46.32, 5.88–47.93, and 5.37–10.68%, respectively. The final pot test showed that the mixed curing agent of modified diatomite had no significant effect on the growth of plants, but it could reduce the Mn, Pb, and Zn accumulation in the upper and lower parts of plants, which is because the acid-soluble and reducible heavy metals in soil transform into an oxidizable and residual state, which reduces the mobility of heavy metals.

Construction and carbon source optimization of a microbial-plant coupled reactor for treating acid mine drainage.

Acid mine drainage (AMD) is recognized as one of the most serious contamination sources in the nonferrous metal mining industry. In this study, aerobic strains VCZ02 and VCZ09, which were identified as Leclercia adecarboxylata and Klebsiella aerogenes, were screened from 11 strains of copper-zinc-resistant bacteria in the soil of the Dexing copper mine with Cu2+/Zn2+ removal rates of 46.32%/41.03% and 57.96%/67.05%, respectively. The composition of extracellular polymers plays an important role in the removal of heavy metals by these two strains. A mixed community consisting of VCZ02 and VCZ09 was coupled with Sagittaria trifolia L.var.sinensis (Sims) Mak to construct a microbial-plant coupled reactor to remediate AMD. Under the optimal condition of sodium acetate as carbon source, the pH of AMD increased from less than 5 to above 6.5, showing Cu2+/Zn2+ removal rates of 70-80% and above 30%, respectively. SEM-EDS results showed that VZC02 and VZC09 in the coupled reactor also helped with resisting the toxicity of heavy metals to plants by forming biofilms on the root surface and increasing the content of heavy metals on the surface of roots, thus improving the treatment effect of plants. This study provides a theoretical basis for the bioremediation of AMD and its application.

Advances in the use of recycled non-ferrous slag as a resource for non-ferrous metal mine site remediation

The growing global demand for non-ferrous metals has led to serious environmental issues involving uncovered mine site slag dumps that threaten the surrounding soils, surface waters, groundwater, and the atmosphere. Remediation of these slags using substitute cement materials for ordinary Portland cement (OPC) and precursors for alkali-activated materials (AAMs) can convert hazardous solid wastes into valuable construction materials, as well as to attain the desired solidification and stabilization (S/S) of heavy metal(loid)s (HM). This review discusses the current research on the effect of non-ferrous slags on the reaction mechanisms of the OPC and AAM. The S/S of HM from the non-ferrous slags in AAM and OPC is also reviewed. HM can be stabilized in these materials based on the complex salt effect and isomorphic effects. The major challenges faced in AAMs and OPC for HM stabilization include the long-term durability of the matrix (e.g., sulfate attack, stability of volume). The existing knowledge gaps and future trends for the sustainable application of non-ferrous slags are also discussed.

Factors influencing lead, mercury and other trace element exposure in birds from metal mining areas

Non-ferrous metal mining is considered one of the largest sources of toxic metal released to the environment and may threaten ecosystems, notably biota. We explored how birds that inhabit non-ferrous metal mining sites are exposed to mercury, lead, and other trace elements by analyzing their feathers and verifying which factors may influence element concentrations in feathers. We sampled a total of 168 birds, representing 26 species, with different feeding habits and migration patterns in a non-polluted reference site and two historical metal mining areas: Almadén, which is considered one of the most heavily mercury-contaminated sites worldwide, and the Sierra Madrona mountains where lead has been mined since ancient times. The quantification of aluminum (Al), arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), thorium (Th), thallium (Tl), uranium (U), vanadium (V) and zinc (Zn) was performed by inductively coupled plasma mass spectrometry (ICP-MS). Feather analysis revealed contamination by Hg and Pb, in Almadén and Sierra Madrona, respectively. We found that granivorous birds had the lowest feather Hg levels compared to those found in omnivorous, insectivorous, and piscivorous species, whereas feather Pb was about twice as high in granivores and omnivores, than in insectivorous and piscivorous birds. We also found differences among study sites in 13 elements and confirmed the influence of feather age, migratory patterns of the birds, and external deposition of elements, on metal concentrations in the feathers. Our results highlight that despite the cessation of metal mining in the study areas, local avifauna are being exposed to Hg and Pb from abandoned mines and old tailings sites, indicating that appropriate measures are needed to protect biota from overexposure to these toxic metals.

Assessing the environmental risk and mobility of cobalt in sediment near nonferrous metal mines with risk assessment indexes and the diffusive gradients in thin films (DGT) technique

The Jialing River is the tributary of the Yangtze River with the largest drainage area. In recent years, the Jialing River has suffered a series of environmental problems, such as discharge of industrial effluent and sand mining activities, which have severely threatened the aquatic ecosystem of the river. In the present study, we employed risk assessment indexes, sequential extraction and the diffusive gradients in thin films (DGT) technique to assess environmental risks and study the remobilization of cobalt (Co) in sediments. The potential ecological risk index and risk assessment code results demonstrated that Co may pose a low environmental and ecological risk to the local aquatic environment. However, BCR sequential extraction showed that the sum of the F1, F2 and F3 fractions of Co still accounted for over 50% of the Co in the study areas, indicating that sediments may be a source of Co release. The DGT results showed an increasing trend for DGT-labile Co in deep sediments (−8 cm to −12 cm), and the calculated flux values ranged from 0.08 to 15.54 ng cm2·day−1, indicating that Co tends to transfer across the sediment-water interface at all sampling sites. Correlation analysis showed that F1–Co, F2–Co and F3–Co are the fractions readily captured by DGT and can be used for predicting Co remobilization in sediment. Sand mining activities contribute substantially to the release of Co from the F1 and F3 fractions as a result of strong stirring of sediments and introduction of oxygen into the sediments. The reductive dissolution of iron (Fe) and manganese (Mn) hydroxides or oxides causes the release of Co and Fe/Mn in the sediment, which leads to Co release from the reducible fraction. The above work suggests that sand mining in the Jialing River should be reasonably regulated to prohibit illegal sand mining activities.

Geochemical features of the impact of the Gayskoye copper pyrite deposit on the environment

The eastern part of the Orenburg region is the largest center of the mining and processing industry of non-ferrous metals in the Ural region. The most significant are copper pyrite deposits containing ores of various chemical compositions. As a result of the study, it was found that in the area of development of the Gayskoye deposit, geochemical halos are developed around ore bodies in the rocks of the Paleozoic, Meso-Cenozoic and weathering crusts. Landscape-geochemical conditions contribute to the wide migration of ore elements and their accumulation in various environments - soils, groundwater, vegetation. Elevated contents of all ore elements are observed, many of them exceed the MAC, Pb, Cu, Zn, As should be attributed to ecologically hazardous elements.

Evaluation of methods and results of dredging waste and dump sampling at ore deposit

The purpose of the study is to assess the reliability of sampling results of concentration tailings at the experimental site of Tereklikan of Kanjol deposit (Tajikistan). The study involves the description of dredging waste and dumps of the site under investigation. The total length of the sampled interval is 12 m. It was divided into two local intervals of 4 and 6 m long according to geological features (amount of veined quartz material). Each type and component of the sampling process including the study of the mineral and chemical composition of ores is of utmost importance in the determination of the quality and quantity of the ore mass (ore), whereas the study of ore mineral and chemical composition is used during prospecting and exploration works for ore minerals (lead, zinc, tin, gold, copper, aluminum, manganese, etc.). The authors substantiate the feasibility for technogenic deposits formed under non-ferrous metals mining to be involved in operation. The methodology and channel sampling results are presented and the reliability of the latter is assessed. The methodology and results of physico-chemical research of concentration tailings via spectral analysis and atomic absorption method are given. The industrial significance of ancient dredging waste and dumps as well as the content of valuable components sufficient for their development has been established. An acceptable technology of dredging waste and dumps processing when involved into operation has been proposed.