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1.
Toxicol Appl Pharmacol ; 464: 116447, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36889513

RESUMO

Although gut microbes can affect the accumulation and metabolism of arsenic (As), the microbes contributing to these processes remain largely unknown. Therefore, this study aimed to investigate the bioaccumulation and biotransformation of arsenate [As(V)] and arsenobetaine (AsB) in mice with a disordered gut microbiome. We used cefoperazone (Cef) to construct a mouse model of gut microbiome disruption along with 16S rRNA sequencing to elucidate the effect of gut microbiome destruction on the biotransformation and bioaccumulation of As(V) and AsB. This revealed the role of specific bacteria in As metabolism. Gut microbiome destruction increased the bioaccumulation of As(V) and AsB in various organs and reduced the excretion of As(V) and AsB in the feces. Further, gut microbiome destruction was found to be important for the biotransformation of As(V). Interference with Cef can significantly decrease Blautia and Lactobacillus while increasing Enterococcus, leading to increase As accumulation in mice and enhanced methylation. We also identified Lachnoclostridium, Erysipelatoclostridium, Blautia, Lactobacillus, and Enterococcus as biomarkers involved in As bioaccumulation and biotransformation. In conclusion, specific microbes can increase As accumulation in the host, exacerbating its potential health risks.


Assuntos
Arsênio , Animais , Camundongos , Arsênio/toxicidade , Arsênio/metabolismo , Bioacumulação , RNA Ribossômico 16S/genética , Biotransformação
2.
Environ Res ; 237(Pt 1): 116904, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37595828

RESUMO

Peatlands account for a significant fraction of the global carbon stock. However, the complex interplay of abiotic and biotic factors governing anaerobic carbon mineralization in response to warming remains unclear. In this study, peat sediments were collected from a typical northern peatland-Changbai Mountain to investigate the behavior and mechanism of anaerobic carbon mineralization in response to depth (0-200 cm) and temperature (5 °C, 15 °C and 20 °C), by integrating geochemical and microbial analysis. Several indices including humification indexes (HI), aromaticity, and water extractable organic carbon (WEOC) components were applied to evaluate carbon quality, while 16S rRNA sequencing was used to measure microbial composition. Regardless of temperature, degradations of carbon quality and associated reduction in microbial abundance as well as diversity resulted in a decrease in anaerobic carbon mineralization (both CO2 and CH4) towards greater depth. Warming either from 5 °C to 15 °C or 20 °C significantly increased anaerobic carbon mineralization in all depth profiles by improving carbon availability. Enhanced carbon availabilities were mediated by the change in microbial composition (p < 0.01) and an increase in metabolic activities, which was particularly evident in the enhanced ß-glucosidase activity and microbial collaborations. A remarkable increase of over 10-fold in the relative abundance of the Geothrix genus was observed under warming. Overall, warming resulted in an enhanced contribution of CH4 emission and a higher ratio of hydrogenotrophic methanogenesis, as evidenced by carbon isotope fractionation factors. In addition, deep peat soils (>100 cm) with recalcitrant carbon demonstrated greater temperature sensitivity (Q10: ∼2.0) than shallow peat soils (Q10:∼1.2) when temperature increased from 15 °C to 20 °C. The findings of this study have significantly deepened our understanding for mechanisms of carbon quality and microbe-driven anaerobic carbon mineralization in peatlands under global warming.

3.
Fa Yi Xue Za Zhi ; 38(3): 400-407, 2022 Jun 25.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-36221836

RESUMO

Abstrct: Metabonomics is a relative discipline that develops after genomics and proteomics, and it is an important component of systems biology. It uses high-throughput and high-sensitivity instruments to perform qualitative and quantitative analysis of all metabolic components in specific biological samples under limited conditions and combines with multivariate statistics to analyze and process the data to obtain information about physiological, pathological or toxicological changes in organisms. In recent years, because of the complicated mechanism of substance abuse and the continuous emergence of new psychoactive substances, metabonomics is increasingly used in substance abuse research. Therefore, this article reviews the application of metabonomics of substance abuse in the toxic mechanism, the mechanism of addiction and the discovery of biomarkers.


Assuntos
Metabolômica , Transtornos Relacionados ao Uso de Substâncias , Biomarcadores , Humanos , Proteômica
4.
J Nat Prod ; 81(2): 335-342, 2018 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-29406718

RESUMO

The medicinal plant Catharanthus roseus accumulates large numbers of terpenoid indole alkaloids (TIAs), including the pharmaceutically important vinblastine, vincristine, ajmalicine, and serpentine. The phytohormone ethylene or methyl jasmonate (MeJA) can markedly enhance alkaloid accumulation. The interaction between ethylene or MeJA in the regulation of TIA biosynthesis in C. roseus is unknown. Here, a metabolomics platform is reported that is based on liquid chromatography (LC) coupled with time-of-flight mass spectrometry to study candidate components for TIA biosynthesis, which is controlled by ethylene or MeJA in C. roseus. Multivariate analysis identified 16 potential metabolites mostly associated with TIA metabolic pathways and seven targeted metabolites, outlining the TIA biosynthesis metabolic networks controlled by ethylene or MeJA. Interestingly, ethylene and MeJA regulate the 2-C-methyl-d-erythritol 4-phosphate (MEP) and acetate-mevalonate (MVA) pathways through AACT and HMGS and through DXS, respectively, to induce TIA biosynthesis in C. roseus. Overall, both nontargeted and targeted metabolomics, as well as transcript analysis, were used to reveal that MeJA and ethylene control different metabolic networks to induce TIA biosynthesis.


Assuntos
Acetatos/metabolismo , Catharanthus/metabolismo , Ciclopentanos/metabolismo , Etilenos/metabolismo , Redes e Vias Metabólicas/fisiologia , Oxilipinas/metabolismo , Alcaloides de Triptamina e Secologanina/metabolismo , Cromatografia Líquida/métodos , Espectrometria de Massas/métodos , Metabolômica/métodos , Ácido Mevalônico/metabolismo , Vimblastina/metabolismo , Vincristina/metabolismo
5.
J Asian Nat Prod Res ; 20(5): 494-499, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-28948829

RESUMO

Phytochemical investigation of the barks of Juglans mandshurica Maxim led to the isolation, purification, and identification of one new lignan named Juglansol A (1), along with nine known compounds (2-10). Their structures were determined by the results of UV, IR, CD, HRESIMS, 1D, and 2D NMR spectroscopic analysis. Compounds 1-10 were evaluated for their cytotoxicities against A549, HepG2, Hep3B, Bcap-37, and MCF-7 cell lines. The results showed that compound 2 possessed stronger cytotoxicities against the tested tumor cell lines compared with positive control 5-fluorouracil.


Assuntos
Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Juglans/química , Lignanas/química , Lignanas/farmacologia , Casca de Planta/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos
6.
J Sep Sci ; 39(14): 2728-35, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27233468

RESUMO

A sensitive and selective ultra high performance liquid chromatography with tandem mass spectrometry method was established and validated for the simultaneous determination of hydroxy-α-sanshool, hydroxy-ß-sanshool, and hydroxy-γ-sanshool in rat plasma after the subcutaneous and intravenous administration of an extract of the pericarp of Zanthoxylum bungeanum Maxim. Piperine was used as the internal standard. The analytes were extracted from rat plasma by liquid-liquid extraction with ethyl acetate and separated on a Thermo Hypersil GOLD C18 column (2.1 mm × 50 mm, 1.9 µm) with a gradient elution system at a flow rate of 0.4 mL/min. The mobile phase consisted of acetonitrile/0.05% formic acid in water and the total analysis time was 4 min. Positive electrospray ionization was performed using multiple reaction monitoring mode for the analytes. The calibration curves of the three analytes were linear over the tested concentration range. The intra- and interday precision was no more than 13.6%. Extraction recovery, matrix effect, and stability were satisfactory in rat plasma. The developed and validated method was suitable for the quantification of hydroxy-α-sanshool, hydroxy-ß-sanshool, and hydroxy-γ-sanshool and successfully applied to a pharmacokinetic study of these analytes after subcutaneous and intravenous administration to rats.


Assuntos
Amidas/farmacocinética , Anestésicos/farmacocinética , Zanthoxylum/química , Amidas/análise , Anestésicos/análise , Cromatografia Líquida de Alta Pressão , Extração Líquido-Líquido , Estrutura Molecular , Espectrometria de Massas em Tandem
7.
Opt Express ; 23(11): 13752-60, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26072747

RESUMO

We have fabricated the surface plasmon (SP) coupled GaN-based nanorod LEDs with Ag nanoparticles (Nps), and demonstrate the enhancement of the optical modulation bandwidth by SPs. Compared with the LED without Ag Nps, the optical modulation bandwidth of the LED with Ag Nps increases by a factor of ~2 at 57 A/cm2. The photoluminescence (PL) and electroluminescence (EL) experimental results are consistent with each other, and both suggest the effective coupling between quantum wells (QWs) and SPs. Furthermore, the current dependent modulation frequency characteristics show that the QW-SP coupling can increase the modulation bandwidth, especially for LEDs with high intrinsic internal quantum efficiency (IQE). These findings will help to open a new solution to design the ultrafast LED light source for the application of the visible light communication.

8.
Environ Sci Technol ; 49(9): 5441-9, 2015 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-25850807

RESUMO

The reactivity of natural dissolved organic matter toward sulfide and has not been well studied with regard to electron transfer, product formation, and kinetics. We thus investigated the abiotic transformation of sulfide upon reaction with reduced and nonreduced Sigma-Aldrich humic acid (HA), at pH 6 under anoxic conditions. Sulfide reacted with nonreduced HA at conditional rate constants of 0.227-0.325 h(-1). The main transformation products were elemental S (S0) and thiosulfate (S2O3(2-)), yielding electron accepting capacities of 2.82-1.75 µmol e- (mg C)(-1). Native iron contents in the HA could account for only 6-9% of this electron transfer. About 22-37% of S reacted with the HA to form organic S (Sorg). Formation of Sorg was observed and no inorganic transformation products occurred for reduced HA. X-ray absorption near edge structure spectroscopy supported Sorg to be mainly zerovalent, such as thiols, organic di- and polysulfides, or heterocycles. In conclusion, our results demonstrate that HA can abiotically reoxidize sulfide in anoxic environments at rates competitive to sulfide oxidation by molecular oxygen or iron oxides.


Assuntos
Substâncias Húmicas , Sulfetos/química , Água/química , Transporte de Elétrons , Compostos Férricos/química , Ferro/química , Cinética , Oxirredução , Compostos de Sulfidrila/química , Tiossulfatos/química , Espectroscopia por Absorção de Raios X
9.
J Sep Sci ; 38(3): 530-40, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25402838

RESUMO

A simple, specific, and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous quantification of nine compounds including a new compound, rhamnazin-3-Ο-ß-D-(6″-ß-hydroxy-ß-methyglutaryl)-ß-D-glucoside-4'-Ο-ß-D-glucoside, in rat plasma using baicalin as an internal standard. The plasma samples were pretreated and extracted by protein precipitation with 0.2% formic acid in acetonitrile. The analytes were separated on a Thermo Syncronis C18 column by gradient elution with a mobile phase consisting of acetonitrile and 0.1% aqueous formic acid at a flow rate of 0.25 mL/min. The detection of the analytes was performed on an electrospray ionization interface operating in positive-ion and multiple reaction monitoring acquisition modes. The calibration curves of these analytes showed good linearity (r > 0.99) within the test ranges. The lower limit of quantification ranged from 0.4 to 20.1 ng/mL for the analytes. The intra- and interday precision and accuracy were all within ±15%, and the recoveries were higher than 80.0%. The validated method was successfully applied to a pharmacokinetic study of the nine flavonoids after administration of the Viscum coloratum extracts by intravenous injection.


Assuntos
Flavonoides/sangue , Flavonoides/farmacocinética , Extratos Vegetais/química , Viscum/química , Animais , Cromatografia Líquida de Alta Pressão , Flavonoides/administração & dosagem , Flavonoides/química , Injeções Intravenosas , Masculino , Estrutura Molecular , Extratos Vegetais/administração & dosagem , Extratos Vegetais/sangue , Extratos Vegetais/farmacocinética , Ratos , Ratos Wistar , Espectrometria de Massas em Tandem
10.
Opt Express ; 22 Suppl 6: A1596-603, 2014 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-25607317

RESUMO

A surface plasmon (SP)-enhanced nanoporous GaN-based green LED based on top-down processing technology has been successfully fabricated. This SP-enhanced LED consists of nanopores passing through the multiple quantum wells (MQWs) region, with Ag nanorod array filled in the nanopores for SP-MQWs coupling and thin Al(2)O(3) passivation layer for electrical protection. Compared with nanoporous LED without Ag nanorods, the electroluminescence (EL) peak intensity for the SP-enhanced LED was greatly enhanced by 380% and 220% at an injection current density of 1 and 20A/cm(2), respectively. Our results show that the increased EL intensity is mainly attributed to the improved internal quantum efficiency of LED due to the SP coupling between Ag nanorods and MQWs.


Assuntos
Óxido de Alumínio/química , Gálio/química , Iluminação/instrumentação , Nanopartículas Metálicas/química , Semicondutores , Ressonância de Plasmônio de Superfície/instrumentação , Adsorção , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Nanopartículas Metálicas/ultraestrutura , Nanoporos/ultraestrutura , Espalhamento de Radiação
11.
Sci Total Environ ; 927: 172268, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38583629

RESUMO

Due to the inappropriate disposal of waste materials containing lead (Pb) and irrigation with sewage containing Pb, the migration of Pb2+ within the soil profile has been extensively investigated. The conventional Pb2+ block method is challenging to implement due to its complex operational procedures and high construction costs. To address this issue, this study introduces the microbial-induced carbonate precipitation (MICP) technique as a novel approach to impede the migration of Pb2+ in the soil profile. Soil acclimatization with urea resulted in an increased proportion of urease-producing microorganisms, including Bacillus, Paenibacillus, and Planococcaceae, along with heightened expression of urea-hydrolyzing genes (UreA, UreB, UreC, and UreG). This indicates that urea-acclimatized soil (Soil-MICP) possesses the potential to induce carbonate precipitation. Batch Pb2+ fixation experiments confirmed that the fixation efficiency of Soil-MICP on Pb2+ exceeded that of soil without MICP, attributed to the MICP process within the Soil-MICP group. Dynamic migration experiments revealed that the MICP reaction transformed exchangeable lead into carbonate-bound Pb, effectively impeding Pb2+ migration in the soil profile. Additionally, the migration rate of Pb2+ in Soil-MICP was influenced by varying urea amounts, pH levels, and pore flow rates, leading to a slowdown in migration. The Two-site sorption model aptly described the Pb2+ migration process in the Soil-MICP column. This study aims to elucidate the MICP biomineralization process, uncover the in-situ blocking mechanism of MICP on lead in soil, investigate the impact of Pb on key genes involved in urease metabolism, enhance the comprehension of the chemical morphology of lead mineralization products, and provide a theoretical foundation for MICP technology in preventing the migration of Pb2+ in soil profiles.


Assuntos
Carbonatos , Chumbo , Microbiologia do Solo , Poluentes do Solo , Solo , Solo/química , Urease/metabolismo , Precipitação Química
12.
Chemosphere ; 318: 137894, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36657570

RESUMO

The occurrence of imbalanced heavy metals concentration due to anthropogenic hindrances in the aquatic and terrestrial environment has become a potential risk to life after circulating through different food chains. The microbial-induced carbonate precipitation (MICP) method has gradually received great attention from global researchers but the underlying mechanism of heavy metal mineralization is not well-understood and challenging, limiting the applications in wastewater engineering. This paper reviews the metabolic pathways, mechanisms, operational factors, and mathematical/modeling approaches in the MICP process. Subsequently, the recent advancement in MICP for the remediation of heavy metal pollution is being discussed. In the follow-up, the key challenges and prospective associated with technical bottlenecks of MICP method are elaborated. The prospective study reveals that MICP technology could be efficiently used to remediate heavy metal contaminants from the natural environment in a cost-effective way and has the potential to improve soil properties while remediating heavy metal contaminated soil.


Assuntos
Metais Pesados , Poluentes do Solo , Estudos Prospectivos , Metais Pesados/metabolismo , Carbonatos , Biodegradação Ambiental , Solo , Poluentes do Solo/metabolismo , Carbonato de Cálcio/metabolismo
13.
J Sep Sci ; 35(8): 984-93, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22589159

RESUMO

A simple, specific, and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of 3'-hydroxypuerarin, 6''-O-xylosylpuerarin, mirificin, puerarin, 3'-methoxypuerarin and daidzin in rat plasma. After the addition of methanol containing 0.1% formic acid and 10% ascorbic acid, the analytes and rutoside were obtained by protein precipitation, then separated on a Thermo Syncronis C18 column (2.1 mm × 10 cm, 1.7 µm) by gradient elution and monitored using an electrospray ionization interface operating in positive ion and selective reaction monitoring acquisition mode. The calibration curves of these analytes showed good linearity (r > 0.99) within the test ranges. The lower limit of quantification was 0.0200 µg/mL for 3'-hydroxypuerarin, 0.0101 µg/mL for 6''-O-xylosylpuerarin, 0.0100 µg/mL for mirificin and puerarin, 0.0098 µg/mL for 3'-methoxypuerarin, and 0.0090 µg/mL for daidzin. The intraday and interday precision and accuracy were all within 15%. The extraction recoveries were from 74.0 to 95.8%. The validated method was successfully applied to pharmacokinetic studies of the six isoflavonoids in rat plasma after intravenous administration of total flavonoids from Gegen.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/análise , Flavonoides/administração & dosagem , Isoflavonas/sangue , Espectrometria de Massas em Tandem/métodos , Animais , Medicamentos de Ervas Chinesas/farmacocinética , Isoflavonas/farmacocinética , Masculino , Ratos , Ratos Sprague-Dawley
14.
Ying Yong Sheng Tai Xue Bao ; 33(12): 3363-3368, 2022 Dec.
Artigo em Zh | MEDLINE | ID: mdl-36601842

RESUMO

We examined the effects of representative clay minerals, montmorillonite (M) and kaolin (K), on perfluorooctanoic acid (PFOA) transport under saturated conditions. Results showed that low amounts of M or K addition increased and high addition amounts reduced PFOA retardation in quartz sand during the transport. With increasing addition of clay minerals (0-50%, weight ratio), the retardation factor of the M-added system increased from 1.03±0.00 to 1.31±0.03 and then decreased to 0.72±0.06, while that of the K-added system increased to 1.30±0.02 and then decreased to 0.49±0.11. Results of the tracer experiment showed that low amount of M or K addition did not produce preferential flow, while high amount addition induced obvious preferential flow, which resulted in the decrease in PFOA retardation. In addition, due to limitations of the highly negative-charged surface of the M or K modified sand and the solid-liquid ratio of column experiment, the modified M or K sand had low adsorption capacity of PFOA and thus almost did not affect PFOA retention. However, the adsorption and desorption of PFOA by clay minerals might still be responsible for the increases in PFOA retardation with low amount of M or K addition. The results are of great significance for accurately assessing the transport process and eco-environmental risks of PFOA in soil-groundwater systems.


Assuntos
Areia , Dióxido de Silício , Argila , Porosidade , Minerais , Adsorção
15.
J Pharm Anal ; 12(2): 243-252, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35582400

RESUMO

Viscum coloratum (Kom.) Nakai is a well-known medicinal hemiparasite widely distributed in Asia. The synthesis and accumulation of its metabolites are affected by both environmental factors and the host plants, while the latter of which is usually overlooked. The purpose of this study was to comprehensively evaluate the effects of host and habitat on the metabolites in V. coloratum through multiple chemical and biological approaches. The metabolite profile of V. coloratum harvested from three different host plants in two habitats were determined by multiple chemical methods including high-performance liquid chromatography-ultraviolet (HPLC-UV), gas chromatography-flame ionization detector (GC-FID) and ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF/MS). The differences in antioxidant efficacy of V. coloratum were determined based on multiple in vitro models. The multivariate statistical analysis and data fusion strategy were applied to analyze the differences in metabolite profile and antioxidant activity of V. coloratum. Results indicated that the metabolite profile obtained by various chemical approaches was simultaneously affected by host and environment factors, and the environment plays a key role. Meanwhile, three main differential metabolites between two environment groups were identified. The results of antioxidant assay indicated that the environment has greater effects on the biological activity of V. coloratum than the host. Therefore, we conclude that the integration of various chemical and biological approaches combined with multivariate statistical and data fusion analysis, which can determine the influences of host plant and habitat on the metabolites, is a powerful strategy to control the quality of semi-parasitic herbal medicine.

16.
Chemosphere ; 293: 133515, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34990716

RESUMO

Endocrine-disrupting compounds (EDCs), as well as microplastics, have drawn global attention due to their presence in the aquatic ecosystem and persistence in wastewater treatment plants (WWTPs). In the present study, for simultaneous bio-removal of two EDCs, 17α-ethinylestradiol (EE2), bisphenol A (BPA), and a microplastic, polypropylene (PP) four kinds of periphytic biofilms were employed. Additionally, the effect of humic acid (HA) on the removal efficacy of these biofilms was evaluated. It was observed that EE2 and BPA (0.2 mg L-1 each) were completely (∼100%) removed within 36 days of treatment; and the biodegradation of EE2, BPA, and PP was significantly enhanced in the presence of HA. Biodegradation of EE2 and BPA was evaluated through Ultra-high performance liquid chromatography (UHPLC), and Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to determine the mechanism of degradation. Gel permeation chromatography (GPC) and SEM had validated the biodegradation of PP (5.2-14.7%). MiSeqsequencing showed that the community structure of natural biofilm changed after the addition of HA, as well as after the addition of EDCs and PP. This change in community structure might be a key factor regarding variable biodegradation percentages. The present study revealed the potential of periphytic biofilms for the simultaneous removal of pollutants of different chemical natures, thus provides a promising new method for wastewater treatment applications.


Assuntos
Disruptores Endócrinos , Microbiota , Perifíton , Poluentes Químicos da Água , Disruptores Endócrinos/análise , Etinilestradiol/análise , Cromatografia Gasosa-Espectrometria de Massas , Substâncias Húmicas/análise , Microplásticos , Plásticos , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/análise
17.
Ying Yong Sheng Tai Xue Bao ; 32(2): 571-580, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33650367

RESUMO

Peat bogs, which cover only 3% of the global land surface, store about 30% of the global soil carbon (C), and are important carbon pools in terrestrial ecosystems. Dissolved organic matter (DOM) is an important part of carbon cycle in peatland, and also an important participant in biogeo-chemical process of peat. The variation of redox ability of DOM and inorganic ions in surface water, groundwater, and pore water of two sampling peatland (minerotrophic fen, LB; ombrotrophic bog, OS) were analyzed using novel electrochemical method and stable carbon isotope. The results showed that in the LB plot, inorganic elements were rich, and that anaerobic respiration dominated by inorganic electron acceptor was the main process. The redox ability differed across different LB water sources (surface water, groundwater, and pore water), which was mainly affected by the actual redox potentials. Iron and sulfate were generally in reduced state in the profile of pore water. The reaction level and depth of redox active groups of DOM which participated in redox process were influenced by inorganic electron acceptor. In the OS plot, organic matter was extremely rich, and organic electron acceptor contributed significantly in redox process. The redox ability of OS water samples from different sources performed differently, which was also mainly attributed to the actual redox potentials. The redox ability of pore water profile was affected by the chemical composition in peat substance at different depths. Therefore, electron accepting capacities (EAC) and oxidation index (OI) values could be used to identify the redox conditions along the gradient and to indicate the redox state of organic matter in aquatic systems.


Assuntos
Água Subterrânea , Solo , Carbono , Ecossistema , Humanos , Áreas Alagadas
18.
Ying Yong Sheng Tai Xue Bao ; 32(1): 309-316, 2021 Jan.
Artigo em Zh | MEDLINE | ID: mdl-33477239

RESUMO

To reconstruct the deposition rate of polychlorinated biphenyls (PCBs) in different historical periods and to examine the temporal and spatial trend of PCBs pollution, we analyzed the changes of PCBs concentration and deposition rate in peat cores and lake sediments, and evaluated the suitability of peat cores and lake sediments for studying PCBs deposition trend. Through the dating analysis of all samples, we found that peat bog could well record the historical sedimentation of PCBs. PCBs did not degrade in peat, and it was thus feasible to use peatland to examine the settlement of PCBs. In this study, the reconstruction time of ∑11PCBs in peat was from the beginning of 19th century to the beginning of 21st century. The mean inventory of ∑11PCBs in three peat cores of each bog changed between (37.0±5.4) and (47.2 ±27.8) µg·m-2, with the standard deviation between 14.9% and 58.9%. The highest concentration of ∑11PCBs was 6.8 ng·g-1DW, while the maximum deposition rate of reconstructed PCBs was up to 989.7 ng·m-2·a-1. The trend of deposition rate was first increasing and then decreasing. After the year 1980, the deposition rate was substantially decreasing, which was consistent with the prohibition of PCBs production in the United States in 1979. Meanwhile, the analysis of sediment samples in the lake near bog showed that concentration and maximum deposition rate of the lake sediment were comparable to those of the nearby bog. The concentrations of Di- to Hepta-PCB congeners were evenly distributed along the sediment profile. Therefore, lake sediments could not be used to analyze the historical sedimentary model of low order PCBs. This study reconstructed temporal and spatial variation of PCBs in atmospheric environment in different historical periods, which could provide basic data for the evaluation of regional environmental quality.


Assuntos
Bifenilos Policlorados , Poluentes Químicos da Água , Monitoramento Ambiental , Sedimentos Geológicos , Poluentes Químicos da Água/análise , Áreas Alagadas
19.
Sci Total Environ ; 773: 143776, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33261873

RESUMO

Peatlands cover a small portion of the Earth's land surface but hold ~30% of soil carbon (C) globally. However, few studies have focused on the early stage of peatland development, which is a key stage in the initial C sink function of peatlands. An immature peatland is vulnerable to changes in environmental conditions, e.g., temperature and water conditions, as the peat accumulation process can be easily interrupted by such changes. It is important to understand how immature peatlands develop, what conditions are beneficial to this process, and the present status of these important peatlands. Plant macrofossil analysis and geochemical characteristics of peat were used to determine the plant succession and the degree of decomposition at two peatlands developing in the Changbai Mountain region of northeastern China. The results show that during the entire plant community succession, plants in the two studied peatlands are mainly characterized by sedges (Cyperaceae) and mosses (mainly Sphagnum). Plant macrofossil analysis reveals a wetter trend in the Yuan Lake (YL) peatland in the most upper part of peat layer, which provides favorable conditions for peat accumulation and peatland development. The C/N ratios of core Chi Lake (CL) show a steady peat decomposition and accumulation process in the CL peatland. Additionally, there was a clear impact of presence of Sphagnum on the variations in the C/N ratio. In the YL peatland, macro-charcoal pieces indicated that fire events during dry hydrological conditions had great effects on biogeochemical processes within the peatland, affecting peat decomposition and the succession of the local plant community. An increase in major and trace elements suggests only weak disturbance due to the considerable distance to human settlements. This study determines the characteristics of pristine mountainous peatlands and highlights the importance of understanding the regular plant community in the early stage of peatland formation, as well as its potential effects on C sinks.


Assuntos
Mudança Climática , Sphagnopsida , China , Humanos , Plantas , Solo
20.
Chemosphere ; 273: 129694, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33524744

RESUMO

Greenhouse gases (GHGs; particularly, CO2, CH4, and N2O) emission from wastewater treatment systems (WWTS) is one of the inevitable concerns for sustainable development. This indicator is directly linked with the carbon footprint and potential impacts of WWTS on climate change. In this view, various modeling, design, and operational tools have been introduced to mitigate the WWTS associated GHGs, at regional and global scales. In this study, authors have critically reviewed the selected potential operational control strategies for GHGs emission, particularly emitted from the operational stages of biological WWTS. The investigated operational control strategies and/or treatment configurations included intermittent aeration, varying dissolved oxygen, enhanced sludge retention time, coupled aerobic-anoxic nitrous decomposition operation, and microalgae integrated treatment process. Based on this analysis and considering the trade-off between treatment performance of WWTS and GHGs control, an integrated framework is also proposed for existing and upcoming WWTS. The findings of this study and proposed framework will play an instrumental role in mitigating the GHGs at various operational stages of WWTS. Future research works in this direction can lead to a better understanding of investigated operational GHGs emission control strategies in WWTS.


Assuntos
Gases de Efeito Estufa , Purificação da Água , Dióxido de Carbono/análise , Efeito Estufa , Gases de Efeito Estufa/análise , Metano/análise , Óxido Nitroso/análise
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