Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.429
Filtrar
1.
Environ Monit Assess ; 194(6): 419, 2022 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-35543872

RESUMEN

This paper was aimed at providing a perspective on the assessment of land-use dominant transition. Based on the transfer matrix of land-use type, the dynamic degree of dominant morphology transition was measured, and an active degree index was proposed. The spatiotemporal differentiation characteristics were assessed and analyzed by land use change characteristics in different phases. Our assessment resulted in three types of spatiotemporal differentiation of Hainan Province in China. The whole island can be divided into three regions with two parallel lines at 45° based on spatiotemporal differentiation characteristics. The "slow-type" was distributed in four eastern counties (cities), "steady-type" was distributed in 13 central and western counties (cities), and the "active-type" was distributed in four central counties (cities). Over three phases, namely 2010-2011, 2012-2015, and 2015-2018, four levels of spatiotemporal differentiation of the 21 counties (cities) were assessed, and they were relatively stable, leaping, declining, and unstable. Areas of new construction and fixed assets investments consumed by increased construction land were the positive factors of land-use dominant transition, while output values of secondary industries and area of industrial-mining per capita were the negative factors. Based on these results, a more informative examination of LULC was proposed, and all resulting land management policies will be more targeted and effective.


Asunto(s)
Monitoreo del Ambiente , Minería , China , Ciudades , Industrias , Políticas
2.
Environ Monit Assess ; 194(6): 415, 2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-35536368

RESUMEN

This study was conducted to find out characteristics of trace element levels and those impacts to organisms at a former uranium (U) mining site. Concentrations of trace elements (Li, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Cs, Ba, Pb, Bi, and U) were determined in sediments, water, and three organism types (insects, frogs, and newts) from three zones in the former U mining site, Ningyo-toge in Japan. Concentrations of As and U in the sediments and water samples were the highest at the mill tailings pond (MP) site, where post-U extraction remnants have been accumulated. Additionally, among the organisms analyzed the highest concentrations of these elements/isotopes were found in newts from MP. Considering data analyses of the whole-body element concentrations, bioaccumulation factors, and δ15N values for the organisms, it was concluded that newts might be the most vulnerable species in this location. Further monitoring and more accurate evaluation of the ecological impacts are preferred for this former U mining site.


Asunto(s)
Oligoelementos , Uranio , Ambiente , Monitoreo del Ambiente , Japón , Minería , Oligoelementos/análisis , Uranio/análisis , Agua/análisis
3.
Arch Microbiol ; 204(5): 251, 2022 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-35411412

RESUMEN

Environmental contamination by toxic effluents discharged by anthropogenic activities including the mining industries has increased extensively in the recent past. Microbial communities and their biofilms inhabiting these extreme habitats have developed different adaptive strategies in metabolizing and transforming the persistent pollutants. They also play a crucial role in natural attenuation of these abandoned mining sites and act as a major driver of many biogeochemical processes, which helps in ecological rehabilitation and is a viable approach for restoration of wide stretches of land. In this review, the types of mine wastes including the overburden and mine drainage and the types of microbial communities thriving in such environments were probed in detail. The types of biofilms formed along with their possible role in metal bioremediation were also reviewed. This review also provides an overview of the shift in microbial communities in natural reclamation process and also provides an insight into the restoration of the enzyme activities of the soils which may help in further revegetation of abundant mining areas in a sustainable manner. Moreover, the role of indigenous microbiota in bioremediation of heavy metals and their plant growth-promoting activity weres discussed to assess their role in phytoremedial processes.


Asunto(s)
Metales Pesados , Microbiota , Contaminantes del Suelo , Biodegradación Ambiental , Metales Pesados/toxicidad , Minería , Suelo , Contaminantes del Suelo/análisis
4.
Sci Rep ; 12(1): 6105, 2022 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-35414684

RESUMEN

Rare earth elements are a nonrenewable and important strategic resource, and China is rich in these elements. However, the substantial exploitation of these resources has caused the migration, diffusion, transformation and accumulation of pollution sources, which in turn has a profound impact on the ecological environment of mining areas. Accurate evaluations of resource and environmental carrying capacity (RECC) are important for the green development of mining areas. In this paper, the fuzzy comprehensive evaluation method based on the combination of the AHP (Analytic Hierarchy Process) and entropy methods is used to study the RECC of mine areas in terms of both support capacity and pressure. The Bayan Obo mine in Inner Mongolia, the Longnan mine in Jiangxi, the Weishan mine in Shandong, the Mianning mine in Sichuan, the Pingyuan mine in Guangdong, and the Chongzuo mine in Guangxi, which are typical representative mines, were selected for a horizontal comparison. The results show that, with the exception of the Bayan Obo mine, the support index was greater than the pressure index in terms of mining and human activities in all mining areas. The RECC index ranked order for the mining areas was Bayan Obo > Longnan > Mianning > Pingyuan > Weishan > Chongzuo. In addition, an obstacle degree model was used to identify and extract the main factors affecting the ecological quality of the mine sites. The ratio of investment in environmental pollution control to GDP was the most important factor, of all factors, which limited the improvement in the mine support index. Through the above research, we identified the main factors affecting the ecological carrying capacity of each mining area, providing a scientific basis for formulating corresponding environmental regulations and reducing the environmental pollution caused by rare earth mining.


Asunto(s)
Metales de Tierras Raras , Contaminantes del Suelo , China , Conservación de los Recursos Naturales , Monitoreo del Ambiente/métodos , Contaminación Ambiental , Humanos , Metales de Tierras Raras/análisis , Minería , Contaminantes del Suelo/análisis
5.
Artículo en Inglés | MEDLINE | ID: mdl-35457619

RESUMEN

Dozens of geoparks have been created in the world since the beginning of the 21st century. Their environmental impact is yet to be fully understood. A bibliographical survey was undertaken to systematically review the journal articles devoted to environmental pollution in geoparks. The considered literature focuses on 10 geoparks (many of them are the members of the UNESCO Global Geoparks network) from eight countries, namely, China, Italy, Malaysia, Poland, Portugal, Romania, Russia, and South Korea. Significant pollution was registered in half of these geoparks. Trace metals and metalloids such as arsenic and cadmium are often reported as pollutants. Water pollution is the most common. In many cases, environmental pollution is not related to geoparks, but results from agricultural and industrial activities. Sometimes, this pollution is inherited from past mining activities, and the latter are related to the geoheritage represented in the geoparks. However, there are also examples of pollution triggered by tourist activities in geoparks and the related infrastructural failures. Various mitigation approaches are considered in the literature (establishing monitoring networks, installing filtration membranes, etc.). It is argued that environmental pollution can be used in geoparks for eco-education and eco-awareness initiatives. Research in environmental pollution in geoparks is an emerging field, and does not avoid multiple biases. Nonetheless, the actual importance of this research is undisputable, and it will be demanded in the future.


Asunto(s)
Arsénico , Metaloides , Metales Pesados , Oligoelementos , Arsénico/análisis , China , Monitoreo del Ambiente , Contaminación Ambiental , Metales Pesados/análisis , Minería , Contaminación del Agua
7.
Sci Total Environ ; 828: 154361, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35288140

RESUMEN

The exploitation of ion-adsorption rare earth element (REE) deposits has resulted in large quantities of abandoned mine tailings, which pose significant risks to the surrounding environment. However, the natural evolutional patterns at early successional stages and related biogeochemical dynamics (e.g. nutrient and REE cycling) on such mine tailings remains poorly understood. To this end, a chronosequence of REE mine tailings abandoned for up to 15 years was investigated in a post-mining site in south China. Our results showed that biocrusts were the earliest colonizers on these tailings, reaching a peak of 10% of surface coverage after 10 years of abandonment. Later on, after 15 years, the biocrusts began to be replaced by pioneer plants (e.g. Miscanthus sinensis), suggesting a rather rapid succession. This ecological succession was accompanied by obvious changes in soil nutrients and microbial community structure. Compared to bulk soils, both the biocrusts and rhizospheric soils favored an accumulation of nutrients (e.g. P, S, N, C). Notably, the autotrophic bacteria (e.g. Chloroflexi and Cyanobacteria) with C and N fixation abilities were preferentially enriched in biocrusts, while heterotrophic plant growth promoting bacteria (e.g. Pseudoocardiaceae and Acidobacteriales) were mainly present in the rhizosphere. Moreover, the biocrusts showed a remarkably high concentration of REEs (up to 1820 mg kg-1), while the rhizospheric soils tended to decrease REE concentrations (~400 mg kg-1) in comparison with bulk soils, indicating that the REEs could be redistributed by biological processes. Principal component analysis and mantel tests showed that the concentrations of nutrients and REEs were the most important factors affecting the microbial communities in biocrusts, rhizospheric and bulk soils. In sum, based on the observation of nutrient accumulation and pollutant (i.e. REE) dynamics in the initial successional stages, this work provides a feasible theoretical basis for future restoration practices on REE mine tailings.


Asunto(s)
Metales de Tierras Raras , Contaminantes del Suelo , Metales de Tierras Raras/análisis , Minería , Nutrientes/análisis , Plantas , Rizosfera , Suelo/química , Contaminantes del Suelo/análisis
8.
Environ Monit Assess ; 194(4): 256, 2022 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-35257264

RESUMEN

Open-cast iron mining causes drastic disturbances in soil properties. Recovery of soil chemical and physical properties is essential for successful revegetation and landscape rehabilitation. To identify changes in soil properties during the mining and revegetation process, soil samples were collected from undisturbed sites represented by forest and ferriferous savannas stocking above iron outcrops, called "cangas," in open-pit benches, and in rehabilitation chronosequences of iron waste piles in the Carajás Mineral Province (CMP), Eastern Amazon, Brazil. The samples were analyzed for chemical and physical properties. Our results showed that iron mining operations resulted in significant alteration of the chemical soil properties when forest and canga vegetation are suppressed to form open-pit benches or waste piles in the CMP. Mining substrates showed lower contents of soil organic matter (SOM) and nutrients than undisturbed areas of forests and cangas. In order to achieve the success of revegetation, nutrients have been added prior to plant establishment. We have demonstrated how soil fertility changes along with mineland rehabilitation, and the variation among chronosequence was attributable mainly due to contents of SOM, K, and B in the soil. The slight improvement of SOM found in rehabilitated waste piles reinforces the notion that recovery of soil quality can be a slow process in iron minelands in the CMP.


Asunto(s)
Contaminantes del Suelo , Suelo , Monitoreo del Ambiente , Bosques , Hierro , Minería , Suelo/química
9.
Huan Jing Ke Xue ; 43(3): 1567-1576, 2022 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-35258221

RESUMEN

Using navel orange peels and natural graphite as raw materials, biochar-supported graphene oxide (BGO) material was prepared using an improved hummer and co-pyrolysis method. The effects of BGO on the forms of heavy metals in the soil of a rare earth mining area were investigated via a soil passivation experiment. The soil column leaching experiment was carried out to explore the change characteristics of heavy metal content in leaching filtrate and the vertical migration law of heavy metals in soil, and the accumulation and release model of heavy metals under leaching conditions was determined. The results showed that pH value and organic matter content of soil with BGO composite increased, and acid-extractable Pb of raw ore and tailings soil decreased by 17% and 8.6%, respectively. The content of Mn form in the raw ore soil did not change significantly, whereas the content of acid-extractable, reducible, and oxidizable state in tailings soil decreased. The accumulation and release characteristics of heavy metals in soil could be divided into two stages:rapid release stage and slow stage. The release rate of heavy metals in soil with BGO composite was lower than that without addition, and the Pb and Mn removed from the tailings soil decreased by 2.5% and 28.4%, respectively, compared with that of the control group, whereas the raw ore soil decreased by 5.7% and 1.1%, respectively. The release of heavy metals in soil is a complex reaction process controlled by a variety of diffusion mechanisms. BGO composites can effectively inhibit the migration of heavy metals by increasing soil pH, surface complexation, and precipitation.


Asunto(s)
Grafito , Metales Pesados , Contaminantes del Suelo , Carbón Orgánico/química , Metales Pesados/análisis , Minería , Suelo/química , Contaminantes del Suelo/análisis
10.
J Hazard Mater ; 431: 128542, 2022 06 05.
Artículo en Inglés | MEDLINE | ID: mdl-35248960

RESUMEN

This study aims to provide numerous environmental research approaches to understand the formation of mineral and organic mercury compounds in self-heating coal waste dumps of the Upper Silesian Coal Basin (USCB). The results are combined with environmental and health risk assessments. The mineralogy comprised accessory minerals in the fine fraction of thermally affected waste, i.e., Hg sulfides, most likely cinnabar or metacinnabar. Moreover, other metals, e.g., Pb, Zn and Cu, were found as sulfide forms. Apart from Hg, the ICP-ES/MS data confirmed the high content of Mn, Zn, Pb, Hg, Cr and Ba in these wastes. The high concentration of available Hg resulted in elevated MeHg concentrations in the dumps. There were no correlations or trends between MeHg concentrations and elemental Hg, TS, TOC, and pH. Furthermore, we did not detect microbial genes responsible for Hg methylation. The organic compounds identified in waste and emitted gases, such as organic acids, or free methyl radicals, common in such burn environments, could be responsible for the formation of MeHg. The concentration levels of gases, e.g., benzene, formaldehyde, NH3, emitted by the vents, reached or surpassed acceptable levels numerous times. The potential ecological and human health risks of these dumps were moderate to very high due to the significant influence of the high Hg concentrations.


Asunto(s)
Minas de Carbón , Mercurio , Carbón Mineral , Monitoreo del Ambiente , Gases , Humanos , Plomo , Mercurio/análisis , Minería , Polonia , Instalaciones de Eliminación de Residuos
11.
Arch Environ Contam Toxicol ; 82(3): 379-390, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35244725

RESUMEN

The study was performed on residue-effects datasets from polluted and unpolluted sites in the Nalón River basin (northern Spain). The effects were measured in terms of alteration of field macroinvertebrate communities, and measured as ecological status scores, and number of families and abundance of Ephemeroptera, Plecoptera and Trichoptera (EPT). Non-linear regression models of the field-measured tissue residues in 10 taxa related to the ecological status of the macroinvertebrate communities were used to derive effective tissue residues (ERs). These were estimated for the good/moderate boundary defined by the ecological quality ratio (EQRs) score and for the 50% reduction of EQR and EPT metrics. As, Cu, Hg and Se ERs were calculated for several macroinvertebrate taxa with different feeding styles. The ER dataset allowed us to estimate As and Cu hazardous concentrations (HC), using species sensitivity distribution models, and were interpreted as community thresholds. Further studies for Hg and Se are needed to complete the database required for HC estimation. The reliability and differences of the several thresholds were tested in a risk assessment using a tissue-residue approach (TRA) conducted with field organisms from Cauxa Creek, a tributary from the same basin exposed to high levels of metals in the sediments due to gold mining activities. This risk assessment identified that As and Cu tissue residues satisfactorily explained the reduction in the ecological status of the macroinvertebrate assemblages. Our results indicate that TRA can help in setting future environmental quality standards for the protection of aquatic biota.


Asunto(s)
Invertebrados , Ríos , Animales , Ecosistema , Monitoreo del Ambiente/métodos , Humanos , Minería , Reproducibilidad de los Resultados , Ríos/química
12.
Water Sci Technol ; 85(4): 1321-1334, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35228370

RESUMEN

Copper tailings (CTs) and orthophosphate are major environmental pollutants. CTs cause severe heavy metal pollution, and orthophosphate is one of the primary causes of water body eutrophication. This study aimed to alleviate heavy metal pollution by CTs and the eutrophication of water caused by orthophosphate. To this end, a 50 mg/L orthophosphate was used as a chemically active leaching solution and passed through a CT soil column. The tail water was then collected. Laboratory leaching tests showed that the thermally modified CTs effectively trapped orthophosphate, and the orthophosphate content in the leachate was 0.15 mg/L. After chemical washing, Cu2+, Cd2+, and Zn2+ were tested in the tail water, and the heavy metal ions in the tail water were removed using an advanced treatment technology. After treatment with 20.0 g/L water hyacinth biochar (WHBC), the removal rates (R%) of Cu2+, Cd2+, and Zn2+ were 99.48, 94.94, and 94.84%, respectively. These results demonstrated that this novel scheme for the synergistic purification of CTs and orthophosphate was feasible in the laboratory. This study provides new theoretical guidance and technical support for CT soil heavy metal remediation and water eutrophication treatment.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Cobre , Metales Pesados/análisis , Minería , Fosfatos , Suelo/química , Contaminantes del Suelo/análisis
13.
Ecology ; 103(5): e3666, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35171503

RESUMEN

Artisanal and small-scale gold mining (ASGM) is the primary global source of anthropogenic mercury (Hg) emissions and a large source of landscape change. ASGM occurs throughout the world, including in the Peruvian Amazon. This data set contains measurements of surface water, precipitation, throughfall, leaves, sediment, soil, and air samples from across the Madre de Dios region of Peru, in locations near and remote from ASGM. These data were collected to determine the fate and transport of Hg across the landscape. Samples were collected in 2018 and 2019. Data predominantly included total Hg and methyl Hg concentrations in surface water, precipitation, throughfall, leaves, sediment, soil, and air. Additional water and soil parameters were also measured to better characterize their chemistry. There are no copyright restrictions; please cite this data paper when the data are used in publication.


Asunto(s)
Mercurio , Suelo , Monitoreo del Ambiente , Oro , Mercurio/análisis , Minería , Perú , Hojas de la Planta/química , Agua
14.
Environ Monit Assess ; 194(3): 150, 2022 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-35129689

RESUMEN

With excess potentially harmful elements (PHEs), drinking water is marked unsuitable and could pose some health risks when ingested or absorbed by humans. Different age groups are exposed to varied risk levels of PHEs. Analyzing the health risks of PHEs for several age groups could provide detailed insights for effective water resources management. No known study in Ameka Pb-Zn mine province (Nigeria) investigated the health risks of PHEs in water resources for several age groups. Therefore, in this paper, the carcinogenic and non-carcinogenic health risks (due to ingestion and dermal contact) of PHEs in groundwater resources of this area were investigated for nine age groups. To achieve its aim, this study integrated novel HERisk code, NSFWQI (national sanitation foundation water quality index), and hierarchical clusters (HCs) in modeling the groundwater quality. Standard elemental composition analysis revealed that the groundwater is polluted with PHEs. The NSFWQI indicated that 15% of the analyzed water samples have moderate water quality whereas 85% are unsuitable for drinking. The HERisk code, which considered nine age groups (1 to < 2 years, 2 to < 3 years, 3 to < 6 years, 6 to < 11 years, 11 to < 16 years, 16 to < 18 years, 18 to < 21 years, 21 to < 65 years, and > 65 years), revealed that all the samples pose high chronic and cancer risks to all the age groups due to oral ingestion. However, it was realized that age groups 1 to < 16 and > 65 are posed with higher risks than age groups 18 to < 65. Overall, it was realized that all the age groups are far more exposed to ingest or absorb Se, Co, Cd, Se, As, Ni, and Pb than Cu, Fe, and Zn. Nevertheless, the health risks due to dermal absorption are far lower than the risks due to oral ingestion. Conclusively, children and aging people are more predisposed to the health threats than middle-aged populations. HCs and geospatial maps aided the spatiotemporal analysis of the groundwater quality.


Asunto(s)
Agua Subterránea , Metales Pesados , Contaminantes Químicos del Agua , Niño , Preescolar , Monitoreo del Ambiente , Humanos , Metales Pesados/análisis , Persona de Mediana Edad , Minería , Nigeria , Medición de Riesgo , Contaminantes Químicos del Agua/análisis
15.
J Environ Radioact ; 246: 106835, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35144200

RESUMEN

This work was conducted at Araxá city, Minas Gerais State, Brazil. The aim was to characterize by different approaches weathering rates at six watersheds occurring there. The study area is well-known in the country due to economic and touristic reasons. Beginning in the 1960's and 1970's, nowadays huge mining activities for niobium and phosphate fertilizer exploitation by different companies are taking place there along with the use of natural mineral waters for health treatment, following a tradition that started in the 19th century for tuberculosis treatment. The dataset utilized in this investigation comprised results obtained in the analysis of distinct geochemical compartments, i.e. rocks, soils, bottom sediments, rainwater and surface waters from small hydrographic basins. The waters of three catchments are extensively used by water-supply systems of Araxá city in order to meet the demand of this resource as a possible supply of drinking water for the local community. Hydrochemical (major and trace constituents) and radionuclides (238U, 234U, and 210Po) analyses of rainwater and water bodies samples allowed estimates of the fluxes in each drainage. These fluxes were subtracted from rainfall deposition, yielding positive net values only for bicarbonate and U-isotopes as natural tracers in all watersheds, which allowed to calculate chemical weathering rates of 2.6-38.9 ton/km2yr (bicarbonate) and 0.09-19.8 ton/km2yr (U-isotopes). Physical weathering rates were obtained from 210Pb data in bottom sediments and exceeded 200 to 1.3 × 105 times the chemical weathering rates evaluated by the U-isotopes approach, a finding compatible with others reported in literature but adopting a diverse conceptual framework. Thus, the development of all analytical protocols along this investigation permitted an integrated appraisal of distinct approaches applied to the same selected site, as well as a comparison of weathering rates with other values reported in the literature, improving the knowledge about this subject in Araxá city watersheds. The novel dataset reported in this paper constitutes an aid to the already existing number of weathering rates elsewhere, helping modellers engaged on predicting future landscape changes.


Asunto(s)
Monitoreo del Ambiente , Monitoreo de Radiación , Brasil , Isótopos , Minería , Tiempo (Meteorología)
16.
Artículo en Inglés | MEDLINE | ID: mdl-35206256

RESUMEN

Dust pollution can be severe in urban centers near mines and smelters. Identification of dust sources and assessing dust capturing plant morphological traits may help address the problem. A chromium (Cr) mining and ferrochrome smelting region in Sekhukhuneland, South Africa, was investigated to identify the sources of Cr in soil and plant leaf surfaces and to evaluate the association between Cr sources and plant morphology. Combinations of bi- and multivariate statistical analysis techniques were applied. Non-significant relation between Cr quantities in surface soil and on leaf surfaces suggested negligible Cr dust contribution from soil to leaves. Association among Cr, Fe, Mg, Al, and Si levels on leaf surfaces confirmed their shared origin, possibly from chromite containing dust dispersed by mines, smelters, roads, and tailings. Both plant morphology and Cr sources (number and proximity to mines and roads) conjointly determined Cr dust deposition on leaf surfaces. Air mass movement patterns further identified local polluters, i.e., mines, ferrochrome smelters, and roads, as dominant dust sources in the region. Common plant species showed Cr dust adhesion favouring traits (plant tallness, larger leaf area, dense epicuticular wax structures, and larger stomata) and projected dust mitigation prospects for Sekhukhuneland.


Asunto(s)
Polvo , Metales Pesados , Cromo , Polvo/análisis , Monitoreo del Ambiente , Contaminación Ambiental/análisis , Metales Pesados/análisis , Minería , Sudáfrica
17.
PLoS One ; 17(2): e0263870, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35157729

RESUMEN

The mining industry production is an important pillar industry in China, while its extensive production activities have led to several ecological and environmental problems. Earth observation technology using high-resolution satellite imagery can help us efficiently obtain information on surface elements, surveying and monitoring various land occupation issues arising from open-pit mining production activities. Conventional pixel-based interpretation methods for high-resolution remote sensing images are restricted by "salt and pepper" noise caused by environmental factors, making it difficult to meet increasing requirements for monitoring accuracy. With the Jingxiang phosphorus mining area in Jingmen Hubei Province as the studied area, this paper uses a multi-scale segmentation algorithm to extract large-scale main characteristic information using a layered mask method based on the hierarchical structure of the image object. The remaining characteristic elements were classified and extracted in combination with the random forest model and characteristic factors to obtain land occupation information related mining industry production, which was compared with the results of the Classification and Regression Tree model. 23 characteristic factors in three aspects were selected, including spectral, geometric and texture characteristics. The methods employed in this study achieved 86% and 0.78 respectively in overall extraction accuracy analysis and the Kappa coefficient analysis, compared to 79% and 0.68 using the conventional method.


Asunto(s)
Minería/clasificación , Fósforo , Imágenes Satelitales/métodos , Algoritmos , Monitoreo del Ambiente , Tecnología de Sensores Remotos
18.
J Environ Manage ; 308: 114619, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35121459

RESUMEN

The risk of arsenic (As) contamination from gold mining is a long-term environmental concern for mines worldwide. Researchers have mainly focused on As contamination induced by tailings, however, less attention has been paid mineralogically to differentiate the fate of As among different As-bearing matrices. This paper presents a detailed study of the mineralogical and morphological features of three typical As-bearing matrices (waste rock, ores, and tailings) using bulk chemical, microscopic and spectroscopic analyses, and reveals the geochemical behavior of As in those matrices. Results from mineral composition identified by RoqSCAN revealed that the matrices were dominated by quartz, k-feldspar, albite, muscovite, and clay minerals, with subordinate ankerite, chlorite, smectite, hematite, arsenopyrite, pyrrhotite, apatite, pyrite, halite, and calcite. The sequential extraction scheme indicated that As in waste rock, ores and tailings was mainly hosted in arsenopyrite. Microscopic analysis observed that waste rock was significantly different from the ores and tailings in terms of mineralogical and morphological characteristics. For waste rock, from arsenopyrite to hematite, As content decreased from 46.12 wt% to 3.54 wt%. However, arsenopyrite presented as unweathered euhedral crystals or slight fragmentation in ores and tailings and a narrower oxidation rims than that of waste rock. The leaching test of SPLP showed that the highest As leaching was found in waste rock (0.246 mg/L) which was significantly higher than those in ores (0.080 mg/L) and tailings (0.148 mg/L). The As in waste rock displayed weaker geochemical stability than in ores and tailings, as supported by mineralogy analysis. Health risk assessment suggested waste rock had a higher health risk for both adults and children compared with ores and tailings. These findings reaffirm that understanding of As fate among different source materials is paramount for securing humans from As hazards. More must be done to decelerate the continuous oxidation of waste rock, thus mitigating As release into nature.


Asunto(s)
Arsénico , Arsénico/análisis , Niño , Monitoreo del Ambiente/métodos , Oro/análisis , Humanos , Minería
19.
J Environ Manage ; 308: 114580, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35124317

RESUMEN

Mining waste deposits (MWDs) represent significant and constant pollution source for the environment worldwide, thus it is very important to identify and diminish their environmental impacts. The aim of this study was to determine long-term environmental impacts and their temporal variations of MWDs in Pb-Zn mining districts in Slovenia and assess stability of potentially harmful element (PHE)-bearing phases in stream water. The results showed that investigated MWDs are important source of PHEs in stream sediments and that PHEs mostly occur as fine-grained and liberated PHE-bearing ore minerals. MWDs have generally stronger impact on sediments of smaller streams draining MWDs and main streams close to their confluences, however, fine-grained PHE-bearing material is transported along major watercourses over long distances causing regional pollution. Main ore minerals are mostly soluble in stream water. However, measured PHE leaching potential of MWDs is negligible. PHE levels in stream waters are thus low, demonstrating that drainage of MWDs predominantly contributes to PHE pollution in solid particulate form. Possible long-term remediation solution that would reduce environmental impact is recovery of metals from fine grain size fractions of MWDs, which could become an effective practice in sustainable management of historical MWDs. However, further studies of MWDs' secondary resource potential, processing technology and evaluation of environmental aspects of extraction are needed.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Monitoreo del Ambiente/métodos , Sedimentos Geológicos , Plomo , Metales Pesados/análisis , Minería , Ríos , Eslovenia , Contaminantes Químicos del Agua/análisis , Zinc/análisis
20.
Artículo en Inglés | MEDLINE | ID: mdl-35162135

RESUMEN

This paper reviews the site investigation field data and access work performed between 2016 and 2019 in the study area located close to Gun-dong mine. The research was aimed at defining the cause of sinkholes and their relationship with the underlying karstic limestone bedrock and nearby mining activities. Only a limited number of small sinkholes appeared in 2014, 2016, and 2018 in the agricultural land close to the limestone mine. The previously open pit mine started its underground operations in 2007. Since then, the mine has developed, and is now comprised of, large underground excavations at several levels below the surface. The studies carried out concluded that the appearance of sinkholes may be related to a general lowering of the groundwater table because of nearby agricultural and mining activities and also due to over-extraction of water due to increased urban use. Whilst these are the best determinations, this paper identifies missing elements of the previous investigations mentioned above, some issues with the interpretation of poorly prepared borehole logs and the improper preservation of borehole cores. The authors make recommendations for a systematic approach for implementation of an investigation strategy. This paper concludes that the appearance of sinkholes is a natural phenomenon, developing over geological time. However, human intervention contributes to sinkhole formation, which in urban areas may result in human, property, and economic losses. A better understanding, based on a methodical approach and suitable technologies, can determine the causes of sinkholes and can lead to the formulation of solutions and the implementation of economically and socially acceptable mitigation measures.


Asunto(s)
Monitoreo del Ambiente , Agua Subterránea , Agricultura , Humanos , Minería , República de Corea
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...