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1.
Ecotoxicol Environ Saf ; 191: 110162, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31935557

RESUMO

It is essential and challenged to understand the atmospheric arsenic pollution because it is much more complicated than in water and top-soil. Herein the different behavior of arsenic species firstly were discovered within the ambient PM2.5 collected during daytime and nighttime, winter and summer. The diurnal variation of arsenic species in PMs is significantly correlated with the presence of metallic oxides, specifically, ferrous, titanium and zinc oxides, which might play a key role in the process of the photo-oxidation of As(III) to As(V) with the meteorological parameters and regional factors excluded. Subsequently, the photo conversion of arsenite was detected on metal-loaded glass-fiber filters under visible light. The photo-generated superoxide radical was found to be predominantly responsible for the oxidation of As(III). In order to reveal toxicity differences induced by oxidation As(III), HepG2 cells were exposed to various arsenic mixture solution. We found that the antioxidant enzyme activities suppressed with increasing the As(III)/As(V) ratio in total, followed by the accumulation of intracellular ROS level. The glucose consumption and glycogen content also displayed an obvious reduction in insulin-stimulated cells. Compared to the expression levels of IRS-1, AKT and GLUT4, GLUT2 might be more vulnerable to arsenic exposure and lead to the abnormalities of glucose metabolism in HepG2 cells. Taken together, these findings clarify that the health risk posed by inhalation exposure to As-pollution air might be alleviated owing to the photo-driven conversion in presence of metal oxides.


Assuntos
Poluentes Atmosféricos/análise , Arseniatos/análise , Arsenitos/análise , Glucose/metabolismo , Luz , Metais Pesados/análise , Material Particulado/análise , Poluentes Atmosféricos/efeitos da radiação , Poluentes Atmosféricos/toxicidade , Arseniatos/efeitos da radiação , Arseniatos/toxicidade , Arsenitos/efeitos da radiação , Arsenitos/toxicidade , Células Hep G2 , Humanos , Exposição por Inalação/análise , Modelos Teóricos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Óxidos/análise , Material Particulado/efeitos da radiação , Material Particulado/toxicidade
2.
Environ Monit Assess ; 192(2): 124, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31960198

RESUMO

Investigation on the behavior of elements in the soil is important both in exploration and environmental geochemistry studies. Rare earth elements (REEs) are the most useful among all trace elements. REE studies have shown that they have important applications in igneous, sedimentary, and metamorphic petrology. This work aims to investigate the relationship of these elements with one another and the behavior of the major oxides and trace elements with REEs. Soil samples were obtained from the alteration site possibly related to mineralization and were analyzed for major oxides, trace elements, and REEs. The relationships between the major oxide-trace element/heavy metal and REE were investigated by statistical methods, such as descriptive statistics, correlation coefficient, and principle component analysis. According to the correlation coefficient matrix, light REEs (LREEs) showed weak to moderate negative correlation with MgO and MnO and moderately positive correlation with SiO2 and K2O. No association was detected between the heavy REEs (HREEs) and the main oxides, but a strong positive correlation with LREEs was observed. For the trace elements, LREE showed a weak positive correlation with Ba and Sn and moderate to strong positive correlation with As, Hf, Nb, Rb, Ta, Th, U, W, and Zr. They also displayed weak to moderate correlation with Sc, Co, Zn, Ni, and V. HREE showed weak to moderate positive correlation with Ni, Cs, Ga, Hf, Th, Zr, As, and LREE. Although REEs exhibited no direct correlation with Au and Ag, they showed a good correlation with some trace elements that are related to hydrothermally altered products. This study showed that REEs can also be used in exploration and environmental geochemistry studies by exploiting the relationship between REEs and other trace/heavy metal elements.


Assuntos
Metais Terras Raras/análise , Poluentes do Solo/análise , Oligoelementos/análise , Monitoramento Ambiental/métodos , Metais Pesados/análise , Compostos Orgânicos , Óxidos/análise , Dióxido de Silício/análise , Solo
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117412, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31357051

RESUMO

Molybdenum dichalcogenides MoX2 (X=S, Se) have been found to possess intrinsic peroxidase-like activity. However, molybdenum oxides (MoO2) as peroxidase mimetics have not been exploited yet. Herein, MoO2 nanoparticles were synthesized by a simple hydrothermal method and found to possess the peroxidase-like activity for the first time. MoO2 nanoparticles could catalyze the oxidation of 3,3',5,5'-tetrametylbenzidine (TMB) by H2O2 to produce a blue-color product (oxTMB). The catalytic property and mechanism were investigated by stead-state kinetics experiment and free radicals scavenging experiment, respectively. Acetylcholinesterase (AChE) could catalyze the hydrolysis of acetylthiocholine chloride (ATCh) into thiocholine (TCh), which could reduce oxTMB to decrease the absorbance in solution. In the presence of AChE inhibitor tacrine, the generation of TCh was inhibited and the absorbance was preserved. Based on these properties, a colorimetric assay method was developed for AChE inhibitor tacrine. This work not only broadens the application of the peroxidase mimetics, but also overcome the disadvantages of traditional methods such as expensive, complex and vulnerable to background interference for colorimetric assay of AChE inhibitor.


Assuntos
Inibidores da Colinesterase/análise , Colorimetria/métodos , Nanopartículas Metálicas/química , Molibdênio/química , Óxidos/química , Tacrina/análise , Inibidores da Colinesterase/metabolismo , Cinética , Nanopartículas Metálicas/análise , Molibdênio/análise , Molibdênio/metabolismo , Óxidos/análise , Óxidos/metabolismo , Peroxidases/metabolismo , Tacrina/metabolismo
4.
Environ Pollut ; 255(Pt 3): 113354, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31629223

RESUMO

Agricultural soil is one of the main sink for both heavy metals and nanomaterials (NMs). Whether NMs can impact heavy metals uptake or bioaccumulation in plants is unknown. Here, cucumber plants were cultivated in a multi-heavy metals contaminated soil amended with four types of NMs (SiO2, TiO2, ZnS and MoS2) separately for four weeks. Physiological and biochemical parameters were determined to investigate the impact of NMs on plant growth. Inductively coupled plasma mass spectrometry was employed to determine the metal content in plants. Results showed that none of the tested NMs impacted plants biomass, but all the NMs showed different degrees of reduction in heavy metals bioaccumulation in plant roots, stems and leaves. However, four NMs showed different degrees of reduction in macro and micro nutrients uptake. MoS2 decreased the bioaccumulation of heavy metals (As, Cd, Cr, Cu, Ni, Al, Ti and Pb) for 36.4-60.6% and nutrients (Mg, Fe, K, Si and Mn) for 40.1%-50.1% in roots. Exposure to MoS2 NMs also significantly increased 23.4% of Si in leaves, 205.6% and 83.9% of Mo in roots and stems, respectively. In general, the results of this study showed promising potential for NMs to reduce uptake of heavy metals in crop plants, especially MoS2 NMs. However, the negative impacts of perturbing nutrients uptake should be paid attention as well.


Assuntos
Cucumis sativus/química , Metais Pesados/análise , Nanoestruturas/análise , Poluentes do Solo/análise , Agricultura , Biomassa , Cucumis sativus/crescimento & desenvolvimento , Óxidos/análise , Desenvolvimento Vegetal , Raízes de Plantas/química , Dióxido de Silício/análise , Solo/química , Sulfetos/análise
5.
Mar Pollut Bull ; 149: 110582, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31550573

RESUMO

Phosphorus (P) pollution can trigger severe marine eutrophication, which further leads to harmful algal blooms, and a deterioration of sea water quality. The P burial and regeneration in offshore sediments can directly affect the eutrophication levels of estuarine and coastal ecosystems. Although many researches on redox-dependent P burial and regeneration were studied, such process in the presence of silicate is still poorly understood, and the effects of pyrite formation on organic P (OP) burial and regeneration also remain unclear. In this study, a sulfidic sediment core was collected in the offshore of an estuary in the north Yellow Sea, China. Results indicated that indigenous biological input was found to be the primary source of organic matter in upper sediments. The regenerated P under reducing conditions was dominated by labile FeP and OP. The PO43- released from FeP and OP that could be captured by Al/Fe/Mn (oxyhydr) oxides in surface sediments and Ca minerals in deep sediments. CaP, AlP, unreactive Al/Fe-Si-P and some stable metal chelated OP were the main burial P fractions. Sulfate reduction and formation of insoluble metal sulfides including the pyrite promoted OP decomposition by anaerobic decomposition, removing metal ions from the "metal-OP" chelates and restoring the phosphatase activity.


Assuntos
Sedimentos Geológicos/química , Fósforo/metabolismo , China , Monitoramento Ambiental/métodos , Estuários , Eutrofização , Sedimentos Geológicos/análise , Ferro/análise , Ferro/química , Minerais/química , Oxirredução , Óxidos/análise , Óxidos/química , Oceano Pacífico , Fosfatos/análise , Fosfatos/química , Fósforo/análise , Sulfatos/análise , Sulfatos/química , Sulfetos/análise , Sulfetos/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo
6.
Environ Pollut ; 255(Pt 2): 113156, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31563770

RESUMO

This study investigated the chemical components of fine urban road dust from seven sampling sites, based on which we could predict potential human health effects. The elemental compositions, including the contents of metals and volatile or semivolatile organic compounds, were determined to establish comprehensive chemical profiles of solid road dust. The chemical profiles, consisting of C: H ratio, metal contents, and relative abundances of organic compounds, provided a chemical signature for road dust. To overall cytotoxicity values ranging between 7 and 58%, water extracts contributed less than 15%, and cell death mainly occurred via direct contact with solid-phase components, which possibly indicates that the selected chemical profile of solid-phase road dust components could serve as a strong predictor for BJ and WI-38 cytotoxicity. Pure metal oxides (Cr2O3, CuO, Fe2O3, MnO2, NiO, or ZnO) exhibited a positive dose-response, and the corresponding metal contents in solid road dust were well correlated with cell viability. The principal component analysis (PCA) results suggested that the metal contents were stronger predictors of cytotoxicity than the benzene derivative or hydrocarbon contents. The chemical profiles established in this study could be further utilized to identify candidate health hazard factors in road dust.


Assuntos
Poeira/análise , Monitoramento Ambiental , Poluentes Ambientais/análise , Humanos , Compostos de Manganês/análise , Metais/análise , Óxidos/análise
7.
Artigo em Chinês | MEDLINE | ID: mdl-31495120

RESUMO

Objective: To establish a method for the determination ofsamarium oxide and lanthanum oxide by inductively coupled plasmamass spectrometryin the air of workplace. Methods: Samarium, lanthanum and their compounds in the air of workplace were collected through microporous filter. The samples were digested by nitricacid and perhydrol (V/V=4∶1) and detected by inductively coupled plasmamass spectrometry. Results: The linear range ofsamarium oxide and lanthanum oxide was 0-50.00 µg/L, Sm(2)O(3): y=0.0119x, r=0.9999; La(2)O(3): y=0.0617x, r=0.9998. The detection limits were less than 0.1 µg/L, and the minimum detection concentration were less than 1.52×10(-5) mg/m(3). The sampling efficiency were 100%, the recovery rates were 95.70%-102.01%, and the precision were 0.78%-1.58%. Conclusion: The indicators established in this study are conformed with the requirements of Chinese Occupational Standars of GBZ/T 210.4-2008, "The Guidelines for the Development of Occupational Hygiene StandarsMehods Part 4: Determination of Chemical Substances in the Air of Workplace".


Assuntos
Poluentes Ocupacionais do Ar/análise , Lantânio/análise , Óxidos/análise , Samário/análise , Espectrometria de Massas , Local de Trabalho
8.
Environ Pollut ; 255(Pt 1): 113128, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31521990

RESUMO

Atmospheric deposition, either dry or wet, has been identified as an important pathway of mercury (Hg) input to terrestrial and aquatic systems. Although East Asia is the major atmospheric Hg emission source region, very few studies have been conducted to quantify atmospheric Hg deposition in its downwind region. In this study, 8-year (2009-2016) atmospheric Hg dry deposition was reported at the Lulin Atmospheric Background Station (LABS), a high mountain forest site in central Taiwan. Dry deposition of speciated Hg was estimated using a bi-directional air-surface flux exchange model for gaseous elemental mercury (GEM) and dry deposition models for gaseous oxidized mercury (GOM) and particulate-bound mercury (PBM), making use of the monitored speciated atmospheric Hg concentrations. Annual total Hg dry deposition ranged from 51.9 to 84.9 µg m-2 yr-1, with a multi-year average of 66.1 µg m-2 yr-1. Among the three forms of atmospheric Hg, GEM was the main contributor to the total dry deposition, contributing about 77.8% to the total, due to the high density of forest canopy as well as the much higher concentration of GEM than GOM and PBM at LABS. Mercury dry deposition is higher in winter and spring than in summer and fall, partly due to the elevated Hg concentrations associated with air masses from East and Southeast Asia where with high atmospheric Hg emissions. The mean annual dry/wet deposition ratio of 2.8 at LABS indicated that Hg deposition to forest landscape was governed by dry rather than wet deposition.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Compostos de Mercúrio/análise , Mercúrio/análise , Óxidos/análise , Grupo com Ancestrais do Continente Asiático , Extremo Oriente , Florestas , Gases/análise , Humanos , Estações do Ano , Taiwan
9.
Chemosphere ; 237: 124524, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549647

RESUMO

Permanganate/bisulfite (PM/BS) is a relatively new advanced oxidation process that can degrade organic micropollutants at extraordinary high rates. In this study, the degradability of PM/BS process towards different representative types of compounds was studied by investigating the kinetics, reaction site specificity and transformation chemistry. Acesulfame (ACE) and carbamazepine (CBZ) were two typical compounds containing olefinic moieties. Sucralose (SUC) was selected as a reference compound, and it is without aromatic and olefinic moieties. The kinetics results indicated that ACE and CBZ were effectively degraded while SUC was not. Preferred reaction sites of Mn3+ species was elucidated by identification of the ACE-transformation products (TPs) and CBZ-TPs with UHPLC-QTOF-MS. Seventeen ACE-TPs including two new compounds and eleven CBZ-TPs produced during the PM/BS process were identified and characterized. Transformation pathways revealed that cleavage of olefinic double bonds was the main reaction mechanism. Chemical structures containing electron-donating groups preferentially reacted with electrophilic Mn3+ species during the process. In addition, transformation products of ACE and CBZ during PM/BS process did not induce higher toxicity. This study provides a preliminary interpretation on the selectivity of PM/BS process according to the micropollutants' chemical structures, which hope to shed light on the future development of PM/BS treatment.


Assuntos
Compostos de Manganês/análise , Óxidos/análise , Sulfitos/análise , Poluentes Químicos da Água/análise , Carbamazepina/química , Cinética , Oxirredução , Edulcorantes
10.
Ecotoxicol Environ Saf ; 183: 109548, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31404726

RESUMO

Chemical oxidation has been applied to remove soil contaminants and thereby reduce human and ecological risks from contaminated sites. However, few studies have been conducted on the natural infiltration of oxidant solutions into unsaturated soil. Moreover, the infiltration capacity of oxidant solutions at various concentrations in unsaturated soil has not yet been studied. This study investigated the natural infiltration tendency of oxidant solutions like hydrogen peroxide (H2O2), potassium permanganate (KMnO4), and sodium persulfate (Na2S2O8), in sand and sandy loam. Cumulative infiltration was recorded from a soil column equipped with a Mariotte reservoir. The infiltration rate, sorptivity, and unsaturated hydraulic conductivity were obtained from the cumulative infiltration results. Na2S2O8 showed the highest infiltration rate in both sand and sandy loam, and the infiltration of Na2S2O8 increased as the concentration was increased from 0.05 to 1%. However, the infiltration of KMnO4 and H2O2 solutions was governed more by chemical reaction behavior than by liquid physical properties or soil hydraulic properties. The production of oxides and gas due to reaction induced clogging in flow paths, resulting in less infiltration. Infiltration of H2O2 at concentrations greater than 0.5% was not observed in sand or sandy loam due to gas formation and swelling.


Assuntos
Peróxido de Hidrogênio/química , Oxidantes/química , Permanganato de Potássio/química , Compostos de Sódio/química , Poluentes do Solo/análise , Solo/química , Sulfatos/química , Oxirredução , Óxidos/análise , Medição de Risco
11.
Mar Pollut Bull ; 146: 366-376, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426169

RESUMO

Solid-phase speciation and porewater chemistry measured by the diffusive gradients in thin films (DGT) technique were used to understand the diagenesis of sulfur (S), iron (Fe), and phosphorus (P) in sediments of Jiaozhou Bay (China), which has been impacted by multiple anthropogenic perturbations. Despite water eutrophication, sediments of the bay are low in organic carbon and sulfide, but high in unsulfidized Fe(II). Dissimilatory iron reduction (DIR) prevails in sediments of the bay, and there is no evidence for responses of S and Fe diagenesis to the water eutrophication, which is largely attributable to unique depositional and diagenetic regimes in association with multiple anthropogenic perturbations. Good coupling of porewater Fe2+ and P in the porewaters suggests that P mobilization is driven mainly by DIR. Low Fe2+/P ratios in porewaters imply that oxidative regeneration of Fe oxides within the upper sediments is incapable of efficiently scavenging upward diffusing P.


Assuntos
Sedimentos Geológicos/química , Ferro/química , Fósforo/química , Enxofre/química , Baías , Isótopos de Carbono/análise , China , Monitoramento Ambiental/métodos , Eutrofização , Sedimentos Geológicos/análise , Ferro/análise , Nitrogênio/análise , Oxirredução , Óxidos/análise , Óxidos/química , Fósforo/análise , Água do Mar/química , Sulfetos/análise , Sulfetos/química , Enxofre/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
12.
Environ Int ; 128: 335-342, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31078002

RESUMO

Herein we fabricated the supported single-atom silver catalysts using an in situ molten salt method. The Mn2O3 nanowires supported single-atom silver catalyst (i.e., 0.06 wt% Ag/Mn2O3) exhibited excellent catalytic activity for toluene combustion, with the temperatures required for 50 and 90% of toluene conversions being 170 and 205 °C, respectively, at a space velocity of 40,000 mL/(g h). However, the toluene conversion at 205 °C quickly decreased from 90 to 30% within 2.5 h of on-stream reaction. Based on the various characterization results, we found that there were no aggregation of Ag particles, no change in crystal structure of the Mn2O3 nanowire support, and no carbon deposition on the catalyst surface, and the quick deactivation of 0.06 wt% Ag/Mn2O3 was mainly associated with the low oxygen activation ability. The proper CeO2 addition to the 0.06 wt% Ag/Mn2O3 catalyst was found to not only improve the catalytic activity but also significantly enhance the stability of the catalyst. Toluene conversion at 195 °C over 0.63 wt% CeO2-0.06 wt% Ag/Mn2O3 decreased by only 10% in 50 h of on-stream reaction. Because Ag and CeO2 particles were highly dispersed on the Mn2O3 nanowire support, the oxygen species formed at the surface oxygen vacancies of CeO2 could efficiently migrate to the active sites (i.e., the interface of Ag-Mn2O3) and replenish the surface reactive lattice oxygen species. Thus, the present single-atom silver catalyst is an alternative for commercial noble metal catalysts for the removal of VOCs.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Cério/química , Recuperação e Remediação Ambiental/métodos , Nanofios/análise , Prata/química , Tolueno/análise , Poluição do Ar/análise , China , Recuperação e Remediação Ambiental/instrumentação , Manganês/análise , Óxidos/análise
13.
Environ Pollut ; 248: 1059-1066, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31091638

RESUMO

Enhancing metals phytoextraction using gentile mobilizing agents might be an appropriate approach to increase the phytoextraction efficiency and to shorten the phytoremediation duration. The effect of sulfur-impregnated organoclay (SIOC) on the redistribution of potentially toxic elements (PTEs) among their geochemical fractions in soils and their plant uptake has not yet been studied. Therefore, our aim is to investigate the role of different SIOC application doses (1%, 3% and 5%) on operationally defined geochemical fractions (soluble + exchangeable; bound to carbonate; manganese oxide; organic matter; sulfide; poorly- and well-crystalline Fe oxide; and residual fraction) of Cd, Cr, Cu, Ni, Pb, and Zn, and their accumulation by pea (Pisum sativum) and corn (Zea mays) in a greenhouse pot experiment using a polluted floodplain soil. The SIOC caused a significant decrease in soil pH, and an increase in organic carbon and total sulfur content in the soil. The addition of SIOC increased significantly the soluble + exchangeable fraction and bioavailability of the metals. The SIOC leads to a transformation of the residual, organic, and Fe-Mn oxide fractions of Cd, Cu, Ni, and Zn to the soluble + exchangeable fraction. The SIOC addition increased the potential mobile (non-residual) fraction of Cr and Pb. The SIOC increased the sulfide fraction of Cr, Ni, and Zn, while it decreased the same fraction for Cd, Cu, and Pb. The effect of SIOC on the redistribution of metal fractions increased with enhancing application dosages. Pea accumulated more metals than corn with greater accumulation in the roots than shoots. Application of the higher dose of SIOC promoted the metals accumulation by roots and their translocation to shoots of pea and corn. Our results suggest the potential suitability of SIOC for enhancing the phytomanagement of PTEs polluted soils and reducing the environmental risk of these pollutants.


Assuntos
Biodegradação Ambiental , Metais Pesados/análise , Ervilhas/metabolismo , Poluentes do Solo/análise , Solo/química , Poluentes da Água/análise , Zea mays/metabolismo , Substâncias Húmicas/análise , Compostos de Manganês/análise , Óxidos/análise , Enxofre/análise
14.
Microsc Res Tech ; 82(9): 1384-1391, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31111992

RESUMO

The aims of this study were: (a) to determine if the presence of probiotic bacteria in an aging medium, that is, artificial saliva in this study, has relevant effects on the surface roughness and the chemical composition of two main alloys used in dentistry (NiTi and stainless steel [SS]) and (b) in the case of NiTi, if these effects are influenced by the coating of the alloy (rhodium and titanium nitride). Atomic force microscopy and Raman spectroscopy were used to study the surface morphology and identify metal oxides formed on the surface of the alloys. Experiments demonstrated that the probiotic bacteria Lactobacillus reuteri can induce processes that alter some features of the surface such as roughness and chemical composition. The effect is dependent on the type of alloy and coating. The bacteria increased roughness in the case of uncoated NiTi more than saliva alone (pH = 4.8). Probiotic bacteria tend to decrease the corrosive influence of saliva on NiTi when the alloy is coated with rhodium or titanium nitride and this effect was also evidenced on SS. Raman spectroscopy confirmed that only SS samples are prone to oxidation processes, predominantly associated with exposure to saliva rather than probiotic bacteria.


Assuntos
Ligas Dentárias/química , Lactobacillus reuteri/crescimento & desenvolvimento , Lactobacillus reuteri/metabolismo , Probióticos/metabolismo , Saliva/microbiologia , Propriedades de Superfície , Corrosão , Microscopia de Força Atômica , Óxidos/análise , Análise Espectral Raman
15.
Environ Sci Pollut Res Int ; 26(20): 20550-20559, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31102215

RESUMO

Ground-based ambient air monitoring was conducted to assess the contribution of crop residue burning of wheat (Triticum aestivum) and rice (Oriza sativa) at different locations in three districts (Kaithal, Kurukshetra, and Karnal) of the agricultural state of Haryana in India for two successive years (2016 and 2017). The Air Quality Index (AQI) and concentration of primary pollutants (SOx, NOx, and PM2.5) were determined in rice and wheat crop season, for burning and non-burning periods. During crop residue burning periods, concentrations of SOx, NOx, and PM2.5 were exceeded the NAAQS values by 78%, 71%, and 53%, respectively. A significant increase in SOx (4.5 times), NOx (3.8 times), and PM2.5 concentration (3.5 times) was observed in stubble burning periods as compared to pre-burning (p < 0.05). A positive and significant correlation among the three pollutant concentrations was observed (p < 0.01). The AQI of KA site in Karnal district fell in severely polluted category during 2016 for rice as well as wheat residue burning period, and of KK site in Kaithal during wheat residue burning in year 2017. Results of present study indicate a remarkable increase in pollutant concentration (SOx, NOx, and PM2.5) during the crop residue burning periods. To the best of our knowledge, the outcomes of present study in this region have not been reported in earlier reports. Hence, there is an urgent need to curb air pollution by adopting sustainable harvesting technologies and management of residues.


Assuntos
Agricultura/métodos , Poluição do Ar/análise , Monitoramento Ambiental , Oryza , Triticum , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/normas , Índia , Óxidos de Nitrogênio/análise , Óxidos de Nitrogênio/normas , Óxidos/análise , Óxidos/normas , Material Particulado/análise , Material Particulado/normas , Compostos de Enxofre/análise , Compostos de Enxofre/normas
16.
Chemosphere ; 230: 24-28, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31102868

RESUMO

Lead (Pb) is an important pollutant and is released into the environment in many forms. Different lead compounds have a variety of solubilities and so may impact on lead bioavailability and toxicity when added to soil. In this experimental study, we investigated the bioavailability of Pb in soil spiked with 300, 900 and 1500 mg/kg of Pb-acetate, PbCl2 and PbO using lettuce and wallaby grass. The concentration of Pb in the shoots of both species from control soils (2-3 mg/kg) was similar to previously reported concentrations in plants grown on uncontaminated soils. The Pb concentrations in the plant shoots increased with Pb concentrations in soil for lettuce (R2 = 0.526, P < 0.001) and wallaby grass (R2 = 0.776, P < 0.001). This study demonstrated that Pb bioavailability in soil was not affected by the type of Pb compound added to the soil for both plant species up to 1500 mg/kg Pb concentrations. Instead, the Pb concentration in the plant was best predicted by the total concentration of lead in the soil, irrespective of the original lead compound added to the soil. This research suggests that the original Pb compounds that contaminated the soil are unlikely to be an important factor in assessing Pb bioavailability, and hence risk, in soils.


Assuntos
Chumbo/farmacocinética , Alface/química , Compostos Organometálicos/farmacocinética , Óxidos/farmacocinética , Poaceae/química , Poluentes do Solo/farmacocinética , Disponibilidade Biológica , Chumbo/análise , Compostos Organometálicos/análise , Óxidos/análise , Solo/química , Poluentes do Solo/análise
17.
Environ Pollut ; 251: 484-492, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31103008

RESUMO

Sulfide-rich tailings produced by mineral processing are prone to oxidation and cause many pollution problems in the surrounding environment; therefore, this issue has become a focus of attention. The Tongling Shuimuchong tailings reservoir contains a large amount of sulfide minerals, especially pyrrhotite and pyrite. This reservoir features obvious oxidation in the surface layer, and the slab is very hard. Mineralogical and environmental geochemical analyses were performed on tailings with different degrees of oxidation in the Shuimuchong tailings reservoir to investigate the influence of the formation of the hard oxidized layer on environmental pollution in the tailings pond. The samples were first subjected to particle-size analysis. The shallow tailings were mainly composed of medium particle; the proportions of coarse particle and fine tailings particles were equal; and the proportions of clay and silt were less than those of the other size fractions. Mineralogical analysis showed that pyrrhotite and pyrite were replaced by residual structures in the oxide layer. The secondary minerals goethite, hematite and jarosite were attached to the edges and fractures of sulfide minerals. The samples were geochemically analyzed to determine the total concentrations of 5 elements, the pH and the major anions. The maximum SO42- concentrations of 33,970 and 32,749 mg/kg were observed at a depth of 40 cm in profiles 1 and 2, respectively. Metal sulfide mineral oxidation in the tailings lowered the pH of the materials to values less than 4. The concentration of HCO3- (122-635 mg/kg) in the tailings samples was very low, and the concentration of CO32- was zero. As (53.2-133.7 mg/kg), Pb (24.2-307.5 mg/kg) and Hg (0.03-0.06 mg/kg) were concentrated in the highly oxidized layer at the surface; the Cd content (0.23-10.5 mg/kg) increased with decreasing oxidation degree of the tailings; and the Cr content (38.0-54.9 mg/kg) fluctuated around a certain value.


Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Sedimentos Geológicos/química , Mineração , Óxidos/análise , Sulfetos/análise , China , Minerais/análise , Oxirredução
18.
Environ Sci Pollut Res Int ; 26(20): 20248-20263, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31098908

RESUMO

Currently, activated coke is widely used in the removal of multiple pollutants from industrial flue gas. In this paper, a series of novel FexLayOz/AC catalysts was prepared by the incipient wetness impregnation for NH3-SCR denitrification reaction. The introduction of Fe-La bimetal oxides significantly improved the denitrification performance of activated coke at mid-high temperature, and 4% Fe0.3La0.7O1.5/AC exhibited a superior NOx conversion efficiency of 90.1% at 400 °C. The catalysts were further characterized by BET, SEM, XRD, Raman, EPR, XPS, FTIR, NH3-TPD, H2-TPR, et al., whose results showed that the perovskite-type oxide of LaFeO3 and oxygen vacancies were produced on the catalysts' surfaces during roasting. Fe-La doping enhanced the amount of acid sites (mainly Lewis and other stronger acid sites) and the content of multifarious oxygen species, which were beneficial for NOx removal at mid-high temperature. Moreover, it was investigated that the effect of released CO from activated coke at mid-high temperature on the NOx removal through the lifetime test, in which it was found that a large amount of CO produced by pyrolysis of activated coke could promote the NOx removal, and long-term escaping of CO on the activated coke carrier did not have a significant negative impact on catalytic performance. The results of the TG-IR test showed that volatile matter is released from the activated coke while TG results showed that the weight loss rate of 4% Fe0.3La0.7O1.5/AC only was 0.0015~0.007%/min at 300-400 °C. Hence, 4% Fe0.3La0.7O1.5/AC had excellent thermal stability and denitrification performance to be continuously used at mid-high temperature. Finally, the mechanisms were proposed on the basis of experiments and characterization results.


Assuntos
Compostos de Amônio/análise , Monóxido de Carbono/análise , Carvão Vegetal/química , Óxidos de Nitrogênio/análise , Óxidos/química , Compostos de Cálcio/análise , Catálise , Desnitrificação , Oxirredução , Óxidos/análise , Oxigênio/análise , Temperatura , Titânio/análise
19.
Environ Sci Pollut Res Int ; 26(16): 16316-16330, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30977007

RESUMO

Formation of trihalomethanes (THMs) through excessive chlorination in the supplied water and its carcinogenic nature is a public health concern in many parts of the world, including a couple of neighboring countries in Asia. However, the issue was not yet addressed either in the public health policy or in academia in Bangladesh. Therefore, the objectives of this study are to determine the THM concentration in supplied water, its multiple pathways to the human body, and an estimation of resultant carcinogenic risk to urban dwellers in six different regions of Dhaka city. Thirty-one supplied water samples were collected from 31 different water points located in Purana Paltan, Naya Paltan, Kallyanpur, Shyamoli, Malibagh-Rampura, and Panthapath regions in premonsoon time. Total chlorine and chlorine dioxide (ClO2) and trihalomethane (THM) concentration were determined using UV-VIS spectrophotometer; total organic carbon (TOC), total inorganic carbon, and total carbon concentration were measured using TOC analyzer, and chloroform concentration was determined by applying gas chromatography-mass spectroscopy (GC-MS-MS) in the supplied water samples. Research findings indicate that THM concentration exceeded the USEPA acceptable limit (80 ppb) in all regions except Panthapath. Study results showed that carcinogenic risk via ingestion was higher than the USEPA acceptable limit of 10-6. Carcinogenic risk via dermal absorption and inhalation exposure was lower according to USPEA acceptable limit. To conclude, this study represents the current knowledge about THM concentration in supplied pipeline water and adverse health risk, which signifies that regulatory measures should be taken to reduce the THM concentration.


Assuntos
Exposição Ambiental/análise , Trialometanos/análise , Poluentes Químicos da Água/análise , Abastecimento de Água , Bangladesh , Carbono/análise , Carcinógenos/análise , Carcinógenos/toxicidade , Cloro/química , Compostos Clorados/análise , Clorofórmio/análise , Cidades , Exposição Dietética/análise , Exposição Ambiental/efeitos adversos , Halogenação , Humanos , Óxidos/análise , Medição de Risco/métodos , Trialometanos/toxicidade , Poluentes Químicos da Água/toxicidade
20.
Chemosphere ; 226: 149-158, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30928714

RESUMO

Acid deposition and algae blooms have resulted in great changes in the water chemistry of Taihu Lake; however, there have been few calculated results to describe these processes. Here we used a mass balance model to estimate base cation losses and evaluate the model applicability in this intensively human-impacted watershed based on a long-term database (1985-2015). The results showed that carbonate weathering induced Ca2+ and Mg2+ losses in the watershed were responsible for the increased ion net reaction (INR) of Ca2+and Mg2+ in the lake. While the increase of K+ and Na+ were not appropriate to provide independents check on the mass balance model because they generally entered the lake as human discharges, not reflecting change of the geochemical process in the watershed as the watershed dominant bedrock is carbonate but not silicate. Acid deposition in Taihu region caused decrease in pH, lime potential, and different Ca, Mg species of surface soils. Our field measurements of sediments in the two lake parts showed that the sediment lime potential was significantly higher in the algae dominated lake area than in the hydrophyte-dominated area due to the in-lake alkalinization by algae blooms, indicating that algae blooms played a significant role in the acidification resistance. Meanwhile, the measured lime potential of the watershed soils was lower than that of the sediment, implying a potential risk of acidification in the watershed. This research helps understand the accelerated interactions between human activities and natural geochemical processes and accelerated water chemistry change at the watershed level.


Assuntos
Cátions , Sedimentos Geológicos/química , Lagos/química , Solo/química , Compostos de Cálcio/análise , China , Monitoramento Ambiental/métodos , Eutrofização , Humanos , Concentração de Íons de Hidrogênio , Óxidos/análise
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