Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 13.274
Filtrar
1.
Chemosphere ; 282: 131163, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470177

RESUMO

Cemented paste backfill (CPB) technology is beneficial to the recycling of solid wastes and sustainable development in mines. However, the wetting-drying cycle caused by water intrusion and goaf drainage has a great influence on the waterproof and support performance of CPB. In this study, the hydraulic and mechanical properties of CPB samples under wetting-drying cycles were studied by permeability tests, nuclear magnetic resonance (NMR) tests and uniaxial compression tests. The results show that with the increasing number of wetting-drying cycles, the porosity and permeability of CPB samples increase; the porosity and permeability of CPB samples with small particle size distribution and cementing strength are more sensitive to the increasing number of wetting-drying cycles. During the wetting-drying cycles, the uniaxial compressive strength and elastic modulus of CPB samples gradually deteriorate. This effect is more significant for CPB samples with the smaller particle size distribution and cementing strength. According to the periodic destruction of CPB cemented structures caused by wetting-drying cycles, the deterioration process of mechanical properties of CPB samples can be divided into two stages: initial deterioration stage and re-deterioration stage. The microstructure analysis of CPB samples was used to verify the periodic destruction of the cemented structures. Finally, protective measures of CPB were proposed to ensure the stability of CPB. The CPB with large particle size distribution and cementing strength should be adopted. Besides, the filling rate and the monitoring condition of the goaf can be strengthend to reduce and even avoid wetting-drying cycles.


Assuntos
Resíduos Sólidos , Sulfetos , Materiais de Construção , Mineração , Reciclagem
2.
Environ Monit Assess ; 193(10): 632, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34490524

RESUMO

In southern South America, Brazil, in the state of Santa Catarina, the neglect and lack of environmental supervision during coal mining caused the contamination of surface and groundwater by acid mine drainage (AMD). By the force of the local law, environmental reclamation actions in these abandoned areas have been carried. A scientific work of monitoring and assessment of the water resources within these areas has never been developed, as the efficacy of the reclamation strategies has never been discussed. This work aims to fill this gap by presenting and analyzing the environmental reclamation strategy of a former degraded coal mining area and its impacts on local water resources. The water monitoring plan in Area IV's was carried out in groundwater, and in lentic (ponds) and lotic (rivers) environments of surface waters, fourteen monitoring campaigns were conducted. The results showed that upstream and downstream river points have different water qualities, with the downstream points having poorer water quality, still affected by past mining activities. From the surface water perspective, the reclaiming method adopted was effective in three of the four ponds, presenting problems only in the downstream one. Two hypotheses were proposed; the first hypothesis is that contamination happens due to leaching of the material that still remains on the ponds' banks into the water. Another hypothesis is that the contamination comes from the upstream groundwater inflow into the pond, which runs through the entire area before reaching the pond. Those results serve to further access the actual monitoring perspectives as well as to better develop future reclaiming strategies.


Assuntos
Minas de Carvão , Água Subterrânea , Poluentes Químicos da Água , Brasil , Carvão Mineral/análise , Monitoramento Ambiental , Mineração , Poluentes Químicos da Água/análise , Recursos Hídricos
3.
Sci Total Environ ; 790: 148164, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34380246

RESUMO

Recent studies in the southwestern United States have shown that smelting processes and mine tailings emit heavy metal(loid)s that are distributed via wind dispersion to nearby communities. With increased attention regarding the effect of air pollution on environmental health, communities have begun to use citizen/community-based monitoring techniques to measure the concentration of metal(loid)s and evaluate their air quality. This study was conducted in a mining community to assess the efficacy of foliar surfaces as compared to an inverted disc (frisbee) to sample aerosol pollutants in ambient air. The assessment was conducted by evaluating As, Pb, Cd, Cu, Al, Ni, and Zn concentrations versus distance from a former smelter, statistical and regression analyses, and enrichment factor calculations compared to similar sites worldwide. Both the foliar and frisbee collection methods had a decrease in metal(loid)s concentration as a function of distance from the retired smelter. Statistical calculations show that the collection methods had similar mean concentrations for all of the metal(loid)s of interest; however, the tests also indicate that the frisbee collection method generally collected more dust than the foliar method. The enrichment factors from both collection methods were comparable to similar studies by other mining areas referenced, except for aluminum. Since there is evidence of enrichment, correlation between methods, and citizen/community science potential, these efforts show promise for the field. Further studies should consider alternating the types of plant used for foliar collection as well as collecting samples on a more frequent basis in order to sufficiently categorize results based on meteorological conditions.


Assuntos
Metais Pesados , Poluentes do Solo , Aerossóis , Poeira/análise , Monitoramento Ambiental , Metais Pesados/análise , Mineração , Poluentes do Solo/análise
4.
Environ Monit Assess ; 193(9): 572, 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34387759

RESUMO

Residual pit lakes from mining are often dangerous to sample for water quality. Thus, pit lakes may be rarely (or never) sampled. This study developed new technology in which water-sampling devices, mounted on an unmanned aerial vehicle (UAV), were used to sample three pit lakes in Nevada, USA, during 1 week in 2017. Water-quality datasets from two of the three pit lakes on public lands, Dexter and Clipper, are presented here. The current conditions of the Dexter pit lake were assessed by examining cation and anion concentration changes that have occurred over a 17-year period since the pit lake was last sampled in 2000. Data gathered during this sampling campaign assessed 2017 conditions of the Dexter and Clipper pit lakes by comparing constituent concentrations to the Nevada Division of Environmental Protection (NDEP) pit lake water-quality requirements, indicating that selenium concentrations exceeded regulatory standards. We compared our sampling data for Dexter lake to prior water-quality data from the Dexter pit lake collected in 1999 and 2000. This comparison for the Dexter pit lake indicates that evapoconcentration may have caused increasing cation and anion concentrations. This UAV sampling approach can potentially incorporate the use of additional multiparameter probes: pH, oxygen concentration, turbidity, or chlorophyll. Some limitations of this UAV water-sampling methodology are battery duration, weather conditions, and payload capacity.


Assuntos
Lagos , Água , Monitoramento Ambiental , Mineração , Qualidade da Água
5.
Huan Jing Ke Xue ; 42(9): 4414-4421, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414741

RESUMO

Metal mining is one of the main contributors of soil heavy metals. Previous studies examining the impact of metal mining on surrounding soil have mainly focused on one or a few metal mining areas. However, such studies cannot effectively inform the management of heavy metal pollution in soil at an inter-provincial scale. As part of this study, literature was collected on soil heavy metals (i.e., As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) affected by metal mining in regions of Southwest China (i.e., Yunnan Province, Sichuan Province, Guizhou Province, Chongqing Municipality, and Tibet Autonomous Region); Next, the impact of metal mining on the soil concentrations of these metals was quantified through meta-analysis, and the relationships between the selected factors (i.e., different sub-regions, metal minerals, and land-use types) and soil heavy metal concentrations were explored. Finally, the literature data was tested for publication bias. The results showed that metal mining in Southwest China has significantly increased the concentrations of heavy metals in topsoil. The different metals were ranked according to their weight effect sizes (ES+) in the following order Cd > Pb > Hg > Zn > As > Cu > Ni > Cr. Metal mining in both Sichuan and Yunnan led to higher effect sizes of soil Cd (ES+Sichuan=4.16, ES+Yunnan=3.20) and Pb (ES+Sichuan=3.47, ES+Yunnan=2.54) than those of the other heavy metals, while metal mining in Guizhou led to a higher effect size of soil Hg (ES+=2.80). The effect size of metal mining on soil heavy metals was higher in cultivated soil (ES+=1.42) than in forested soil (ES+=0.50). The mining of lead-zinc and tin significantly increased the concentrations of soil Cd, Pb, and Zn, and the mining of copper significantly increased the concentrations of soil Cu, Cd, and Pb. Of the investigated soil heavy metals in Southwest China, Pb and Zn showed slight potential publication biases (P<0.05). The above results can provide more effective information for the environmental protection of soil in metal mining areas of Southwest China.


Assuntos
Metais Pesados , Poluentes do Solo , China , Monitoramento Ambiental , Metais Pesados/análise , Mineração , Medição de Risco , Solo , Poluentes do Solo/análise
7.
Sensors (Basel) ; 21(16)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34451001

RESUMO

Special regulations have been laid down to establish the principles and requirements for the safety and serviceability of old mining workings which are adapted for tourism. To comply with these regulations the measurements were taken in the Bochnia Salt Mine, which has been in use for 800 years. The presented work demonstrates the use of a sonic probe extensometer in connection with the obtained results of displacement measurements in intact rocks surrounding the gallery. There were also test measurements carried out for determination of the real accuracy of the instrument. The presented study of deformations detected by electromagnetic extensometer measurements is presumed to be the first time that research has been made in salt mines operating in rock mass affected by tectonic stress. The paper presents the process of rock salt flow into the gallery observed over a period of 3 years. It is an unprecedented depiction of salt deformation subjected to natural stresses. One of the more surprising results presented here is the discovery of the occurrence of a specific distribution of strain around the measured gallery. The results of measurements showed that the southern part of the intact rock mass surrounding the passage is more compressed (strain rate 3.6 mm/m/year) than the northern one (strain rate 1.6 mm/m/year). This illustrates the presence and influence of additional tectonic effects resulting from the Carpathian push. These observations represent a new kind of research into tectonic stress and tectonic activity in underground measurements.


Assuntos
Mineração , Cloreto de Sódio
8.
Environ Monit Assess ; 193(9): 606, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34453609

RESUMO

The collapse of mining tailing dams in Brumadinho, Minas Gerais, Brazil, that occurred in 2019 was one of the worst environmental and social disasters witnessed in the country. In this sense, monitoring any impacted areas both before and after the disaster is crucial to understand the actual scenario and problems of disaster management and environmental impact assessment. In order to find answers to that problem, the aim of this study was to identify and analyze the spatiality of the impacted area by rupture of the tailing dam of the Córrego do Feijão mine in Brumadinho, Minas Gerais, by using orbital remote sensing. Land use and land occupation, phytoplankton chlorophyll-a, water turbidity, total suspended solids on water, and carbon sequestration efficiency by vegetation (CO2Flux) were estimated by orbital imagery from the Landsat-8/OLI and MSI/Sentinel-2 sensors in order to assess the environmental impacts generated by the disaster. Data were extracted from spectral models in which the variables that best demonstrated the land use variation over the years were sought. Mean comparison by t-test was performed to compare the time series analyzed, that is, before and after the disaster. Through the analysis of water quality, it was observed that the environmental impact was calamitous to natural resources, especially water from Córrego do Feijão.


Assuntos
Monitoramento Ambiental , Tecnologia de Sensoriamento Remoto , Brasil , Meio Ambiente , Mineração
10.
Artigo em Inglês | MEDLINE | ID: mdl-34444052

RESUMO

Antibiotic resistance (AR) in the environment is of great global concern and a threat to public health. Soil bacteria, including Bacillus spp., could act as recipients and reservoirs of AR genes of clinical, livestock, or agricultural origin. These genes can be shared between bacteria, some of which could be potentially human pathogens. This process can be favored in conditions of abiotic stress, such as heavy metal contamination. The Almadén mining district (Ciudad Real, Spain) is one of the environments with the highest mercury (Hg) contamination worldwide. The link between heavy metal contamination and increased AR in environmental bacteria seems clear, due to co-resistance and co-selection phenomena. In the present study, 53 strains were isolated from rhizospheric and bulk soil samples in Almadén. AR was tested using Vitek® 2 and minimum inhibitory concentration (MIC) values were obtained and interpreted based on the criteria of the Clinical and Laboratory Standards Institute (CLSI) guidelines. Based on the resistance profiles, five different antibiotypes were established. The Hg minimum bactericidal concentration (MBC) of each strain was obtained using the plating method with increasing concentrations of HgCl2. A total of 72% of Bacillus spp. showed resistance to two or more commonly used antibiotics. A total of 38 isolates expressed AR to cephalosporins. Finally, the environmental co-selection of AR to cephalosporins and tetracyclines by selective pressure of Hg has been statistically demonstrated.


Assuntos
Bacillus , Mercúrio , Bacillus/genética , Resistência Microbiana a Medicamentos , Humanos , Mercúrio/análise , Mineração , Solo
11.
Artigo em Inglês | MEDLINE | ID: mdl-34360386

RESUMO

As one of the main industrial solid wastes, there are a large number of free alkaloids, chemically bound alkaloids, fluoride, and heavy metal ions in Bayer process red mud (BRM), which are difficult to remove and easily pollute groundwater as a result of open storage. In order to realize the large-scale industrial application of BRM as a backfilling aggregate for underground mining and simultaneously avoid polluting groundwater, the material characteristics of BRM were analyzed through physical, mechanical, and chemical composition tests. The optimum cement-sand ratio and solid mass concentration of the backfilling were obtained based on several mixture proportion tests. According to the results of bleeding, soaking, and toxic leaching experiments, the fuzzy comprehensive evaluation method was used to evaluate the environmental impact of BRM on groundwater. The results show that chemically bound alkaloids that remained in BRM reacted with Ca2+ in PO 42.5 cement, slowed down the solidification speed, and reduced the early strength of red mud-based cemented backfill (RMCB). The hydration products in RMCB, such as AFT and C-S-H gel, had significant encapsulation, solidification, and precipitation inhibition effects on contaminants, which could reduce the contents of inorganic contaminants in soaking water by 26.8% to 93.8% and the leaching of toxic heavy metal ions by 57.1% to 73.3%. As shown by the results of the fuzzy comprehensive evaluation, the degree of pollution of the RMCB in bleeding water belonged to a medium grade Ⅲ, while that in the soaking water belonged to a low grade II. The bleeding water was diluted by 50-100 times to reach grade I after flowing into the water sump and could be totally recycled for drilling and backfilling, thus causing negligible effects on the groundwater environment.


Assuntos
Água Subterrânea , Metais Pesados , Materiais de Construção , Resíduos Industriais/análise , Mineração
12.
Chemosphere ; 277: 130131, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34384166

RESUMO

The scavenging of soluble metals by iron (Fe) and aluminium (Al) oxyhydroxides is a natural process that occurs in acid mine drainage (AMD). This phenomenon is relevant to the immobilization, transport, and recovery of important natural resources such as rare earth elements (REE) and uranium (U). Furthermore, understanding the players and the reactions that govern the scavenging of REE and U by Fe and Al oxyhydroxides in aqueous systems is fundamental for natural and engineering sciences and for environmental management. In this scenario, the current work investigated the role of iron in the co-precipitation of REE and U when treating effluents by pH neutralization in an AMD system located in Brazil. The research employed water sampling, co-precipitation batch experiments, sequential extraction, X-ray diffraction and 57Fe Mössbauer spectroscopy. The results revealed that the presence and the amount of Fe in the initial solution can influence the REE removal efficiency positively. The effect of the addition of Fe over the REE removal efficiency was irrelevant when the pH of the AMD was raised to values equal to 7-8. The scavenging of U was not influenced by the addition of Fe to the AMD. The sequential extraction results showed that precipitates containing higher amounts of Fe tend to be less labile. The 57Fe Mössbauer spectra revealed that the REE can occupy iron sites in the structure of the amorphous precipitates. The findings of the current study can be extrapolated to other AMD systems and contribute to the development of novel REE recovery and hydrometallurgical techniques.


Assuntos
Metais Terras Raras , Urânio , Poluentes Químicos da Água , Alumínio , Ferro , Metais Terras Raras/análise , Mineração , Poluentes Químicos da Água/análise
13.
J Environ Manage ; 296: 113411, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34351286

RESUMO

Uranium-containing effluents generated by nuclear energy industry must be efficiently remediated before release to the environment. Currently, numerous microbial-based strategies are being developed for this purpose. In particular, the bacterial strain Stenotrophomonas sp. Br8, isolated from U mill tailings porewaters, has been already shown to efficiently precipitate U(VI) as stable U phosphates mediated by phosphatase activity. However, the upscaling of this strategy should overcome some constraints regarding cell exposure to harsh environmental conditions. In the present study, the immobilization of Br8 biomass in an inorganic matrix was optimized to provide protection to the cells as well as to make the process more convenient for real-scale utilization. The use of biocompatible, highly porous alginate beads for Br8 cells immobilization resulted the best alternative when investigating by a multidisciplinary approach (High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM), Environmental Scanning Electron Microscopy (ESEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance, etc.) several consolidated entrapment methods. This biomaterial was applied to complex real U mining porewaters (containing 47 mg/L U) in presence of an organic phosphate source (glycerol-2-phosphate) to produce reactive free orthophosphates through Br8 phosphatase activity. Uranium immobilization rates around 98 % were observed after one cycle of 72 h. In terms of U removal ability as a function of biomass, Br8-doped alginate beads were determined to remove up to 1199.5 mg U/g dry biomass over two treatment cycles. Additionally, optimized conditions for storing Br8-doped beads and for a correct application were assessed. Results for U accumulation kinetics and HAADF-STEM/ESEM analyses revealed that U removal by the immobilized cells is a biphasic process combining a first passive U sorption onto bead and/or cell surfaces and a second slow active biomineralization. This work provides new practical insights into the biological and physico-chemical parameters governing a high-efficient U bioremediation process based on the phosphatase activity of immobilized bacterial cells when applied to complex mining waters under laboratory conditions.


Assuntos
Urânio , Alginatos , Biodegradação Ambiental , Mineração , Stenotrophomonas , Urânio/análise
14.
Artigo em Inglês | MEDLINE | ID: mdl-34360233

RESUMO

Fish serves as the principal source of animal protein for the indigenous people of the Amazon, ensuring their food and nutritional security. However, gold mining causes mercury (Hg) contamination in fish, and consequently increases health risks associated with fish consumption. The aim of this study was to assess the health risk attributed to the consumption of mercury-contaminated fish by Munduruku indigenous communities in the Middle-Tapajós Region. Different fish species were collected in the Sawré Muybu Indigenous Land to determine mercury levels. The health risk assessment was carried out according to the World Health Organization (WHO 2008) methodology and different scenarios were built for counterfactual analysis. Eighty-eight fish specimens from 17 species and four trophic levels were analyzed. Estimates of Hg ingestion indicated that the methylmercury daily intake exceeds the U.S. EPA (United States Environmental Protection Agency) (2000) reference dose from 3 to 25-fold, and up to 11 times the FAO (Food and Agriculture Organization)/WHO (2003) dose recommendation. In all situations analyzed, the risk ratio estimates were above 1.0, meaning that the investigated Munduruku communities are at serious risk of harm as a result of ingestion of mercury-contaminated fish. These results indicate that, at present, fish consumption is not safe for this Munduruku population. This hazardous situation threatens the survival of this indigenous population, their food security, and their culture.


Assuntos
Mercúrio , Compostos de Metilmercúrio , Animais , Brasil/epidemiologia , Exposição Ambiental/análise , Monitoramento Ambiental , Peixes , Contaminação de Alimentos , Humanos , Mercúrio/análise , Mercúrio/toxicidade , Compostos de Metilmercúrio/análise , Compostos de Metilmercúrio/toxicidade , Mineração , Medição de Risco
15.
Environ Monit Assess ; 193(9): 599, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34432167

RESUMO

Rehabilitation of degraded lands due to mining and other activities requires rebuilding of the appropriate soil structure and microbial integrity. Organic wastes, in particular plant-based materials, play a vital role in restoration of degraded land when used as amendments for topsoil integrated with microbe-assisted phytoremediation. In this present study, a biotechnological approach using the combination of organic waste amendments, i.e., ETP (effluent treatment plant), sludge from sugarcane and paper industry, and the press mud respectively along with microbial and fungal inoculum isolated from the soil rhizosphere have been applied to study the influence on fertility and productivity of mine spoil from manganese and coal dumps. The organic amendments applied as 100-ton ha-1 and application of biofertilizers boosted the survival of plants such as Tectona grandis (Teak), Dalbergia sisso (North Indian rosewood), Phyllanthus emblica (Indian gooseberry), Gmelina arborea (Gamhar), and Acacia auriculiformis (Earpod wattle) from 80 to 100% with robust growth and development during the short span of 25 years. The physicochemical attributes of soil and the microbial count also increased significantly. The pH of mine soil dumps slightly shifted toward alkaline conditions (7.4 to 7.8) whereas bulk density, porosity, and the water holding capacity were greatly improved. Other than this, the nutrient status of mine dump soil and the plants such as available nitrogen, phosphorus, potassium and the organic carbon content in soil were improvised to a greater extent simultaneously decreasing the available manganese concentration. The findings of the study assure a better land reclamation and restoration approach.


Assuntos
Poluentes do Solo , Monitoramento Ambiental , Mineração , Solo , Poluentes do Solo/análise , Desenvolvimento Sustentável
16.
Environ Monit Assess ; 193(9): 600, 2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34435259

RESUMO

Gishwati forest is part of Gishwati-Mukura National Park. It has a long history of degradation due to human activities. Despite many efforts initiated to restore and protect this concession, the mining activities continue to affect its biodiversity. This study aims at assessing the impact of mining on the landscape, quality of water, soil, and vegetation in Gishwati and its vicinity. Data were collected from five mining sites and one non-mined control site. Methods included direct field observations of the landscape, physico-chemical analysis of water, mine tailings analysis and vegetation inventory, and measurement of the concentrations of metals/metalloids in both water and soil (mine tailings). The findings revealed that mining has accelerated the erosion and the stream/river sedimentation and has created new landforms around some mining sites. The physico-chemical properties of mine tailings piled and scattered on mining sites are not conducive for biodiversity, and the concentrations of metals and metalloids in the water and soil are generally higher on mining sites than on the non-mined area and even higher than international standards. Such high metal/metalloid concentrations threaten both aquatic and terrestrial life as they are likely to cause the extinction of a good number of vegetation species on mining sites. They may also cause toxicity and lead to migration of a variety of animals living in Gishwati. The study recommends the use of mining best practices to safeguard biodiversity in the Gishwati area.


Assuntos
Monitoramento Ambiental , Mineração , Animais , Humanos , Rios , Ruanda , Solo
17.
Environ Sci Process Impacts ; 23(8): 1220-1230, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34318847

RESUMO

Smelting activities at Giant Mine (Yellowknife, NWT, Canada) have resulted in high sulfate and arsenic concentrations in nearby lakes. Here we tested whether historic smelting affects current mercury (Hg) cycling in 35 freshwater lakes over a 2800 km2 area around the former gold mine. We sampled lake water and sediment over three consecutive years (2015-2017) using a factorial sampling design that accounted for different environmental variables known to affect the net methylmercury (MeHg) levels in water. Stable Hg(ii) and MeHg isotope tracers were used to quantify Hg methylation and demethylation rate constants in sediments, and 16S rRNA gene amplicon sequencing was used to characterize microbial community structure. This study reveals that the fraction of methylated total Hg (% MeHg) found in surface water is positively correlated to the sulfate gradient, while the rate at which Hg is methylated (Km) in sediments is negatively correlated with total arsenic, and positively correlated with dissolved organic carbon, total phosphorous, and % MeHg in the water. Furthermore, 6 of the 28 lakes that had detectable demethylation rate constants (Kd) also had significantly lower DOC concentrations than lakes with non-detectable Kd. Our results also show that legacy pollution from smelting activities is affecting the structure of microbial communities in lake sediments. This study reveals the complex dynamics of Hg cycling in this northern environment, highlighting the importance of large-scale studies in which the effect of multiple pollution gradients (e.g. arsenic and sulfate) must be taken into consideration.


Assuntos
Mercúrio , Compostos de Metilmercúrio , Microbiota , Poluentes Químicos da Água , Monitoramento Ambiental , Sedimentos Geológicos , Ouro , Lagos , Mercúrio/análise , Mineração , RNA Ribossômico 16S/genética , Poluentes Químicos da Água/análise
18.
Sci Total Environ ; 794: 148665, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34218141

RESUMO

Mid-20th century mining in Naabeehó Bináhásdzo (Navajo Nation) polluted soil and groundwater with uranium and arsenic. The Diné and other indigenous residents of this region use groundwater for drinking, livestock, and irrigation, creating a serious environmental health risk. Currently, many individuals and communities on the Navajo Nation must purchase and transport treated water from hours away. Sunflowers (Helianthus annuus) preferentially take up uranium and arsenic, potentially representing a tool to remove these contaminants through on-site, low-cost phytoremediation. This study reports the results of a collaboration among researchers, high school students, teachers, and tribal leaders to analyze water chemistry and perform a phytoremediation experiment. In 2018 and 2019, we compiled existing data from the Navajo Nation Environmental Protection Agency (NNEPA) and collected samples from surface and groundwater. We then used sunflower seedlings grown in local soil to assess whether phytoremediation could be effective at removing arsenic and uranium. For the NNEPA-sampled wells, 9.5% exceeded the maximum contaminant level for uranium (30 µg per liter) and 16% for arsenic (10 µg per liter). For the new samples, uranium was highest in surface pools, suggesting leaching from local soil. Unlike studies from humid regions, sunflowers did not decrease uranium and arsenic in soil water. Instead, there was no change in arsenic concentration and an increase in uranium concentration in both planted and control treatments, attributable to weathering of uranium-bearing minerals in the desert soil. Because much of global uranium mining occurs in arid and semiarid regions, the ineffectiveness of phytoremediation on the Navajo Nation emphasizes the importance of prevention and conventional remediation. More generally, the participatory science approach created meaningful relationships and an important collaboration between a tribal chapter and a university, providing both cultural and scientific experiential learning opportunities for Diné high school students, undergraduate researchers, and senior personnel.


Assuntos
Arsênio , Ciência do Cidadão , Urânio , Arsênio/análise , Biodegradação Ambiental , Humanos , Mineração , Urânio/análise
19.
J Environ Manage ; 297: 113221, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34293675

RESUMO

Heavy metal water pollution is an urgent global problem to be addressed. Copper ions are common toxic heavy metal pollutants in wastewater. In order to remove the excessive copper ions in wastewater, in this study, chicken bone charcoal was modified by sodium dodecyl sulfonate and combined with magnetic nanoparticles prepared with ferric chloride hexahydrate and ferrous sulfate heptahydrate to produce a high efficiency adsorbent. The characterization of the magnetically modified bone charcoal was analyzed by scanning electron microscopy, surface and porosity analyses, FTIR and thermogravimetric analysis. The optimal adsorption conditions of magnetically modified bone charcoal for Cu2+ were obtained through batch experiments. The highest removal rate and adsorption capacity of Cu2+ was 99.98% and 15.057 mg/g, respectively, when the pH was 3.0, adsorbent dosage was 0.2 g, initial concentration of the Cu2+ solution was 50 mg/L, and temperature was 25 °C. The adsorption process fitted well with the Langmuir isotherm and the pseudo-second-order kinetic model. The regeneration experiment indicated that M-SDS-BC-500 maintained a high removal rate after five repetitions. The results suggest that the adsorbent has wide application prospects.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cobre/análise , Concentração de Íons de Hidrogênio , Íons , Cinética , Fenômenos Magnéticos , Mineração , Poluentes Químicos da Água/análise
20.
Environ Res ; 200: 111732, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34324849

RESUMO

SO42-, a major component of acid mine drainage (AMD), plays an important role in study environment of AMD. We investigated the distribution and adsorption-desorption mechanisms of SO42- and the variation of stable isotope of sulfur (δ34S) values in the soil profile polluted by AMD. Results showed that the species and 34S values of SO42- differed significantly among different soil depths. In the surface soil (0-20 cm), native water-soluble SO42- (WSS) in the range ~85 % total SO42- was the dominant species. There was a peak of adsorption, which correlated significantly with amorphous oxide Fe, indicating that iron oxides and pH was fundamentally proportional to SO42- forms. The high concentrations of Cu2+ and Pb2+ also played important roles in form of SO42- in soil profile. Desorption kinetics of explained three SO42--bound forms. The trend mean δ34S values of WSS and AS in soil vertical profile was very similar with increasing from surface to subsurface, and have lower δ34S values than those of total sulfur, indicating that mineralization of organic sulfur should produce SO42- that was more depleted in δ34S. SO42- desorbed and trend δ34S values could provide reasonable explanation for the migration of SO42-. In the AMD irrigation scope, the higher SO42- concentration was reserved by immobilized as organic sulfur, and then main approach of SO42- migration was desorption and organic sulfur mineralize in now stage.


Assuntos
Poluentes do Solo , Solo , Mineração , Poluentes do Solo/análise , Sulfatos , Enxofre
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...