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1.
J Colloid Interface Sci ; 613: 337-348, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35051719

RESUMO

Effective removal of polybrominated diphenyl ethers (PBDEs) from the environment is essential for the ecosystem and human health. Reductive debromination of PBDEs by nanoscale zerovalent iron (nZVI) has become an important technology. However, the agglomeration and low persistence catalytic activity of nZVI particles have become urgent problems to be improved. Herein, we report the first application of a new organo-attapulgite (OA) supported Fe/Pd nanoparticles (OA-Fe/Pd) composite for decabromodiphenyl ether (BDE209) removal. BDE209 was efficiently removed using OA-Fe/Pd with a reaction rate that was 9.97 times greater than that of the nZVI due to the synergetic effect of support material OA and Pd loading. OA could prevent nZVI particles from agglomeration and adsorb BDE209 molecules to its surface. Pd could supply atomic hydrogen and also prevent the oxidation of nZVI particles. The degradation of BDE209 by OA-Fe/Pd was affected by many factors and followed pseudo first-order kinetics. The degradation of BDE209 by OA-Fe/Pd underwent a stepwise debromination manner with the H-transfer dominant mechanism. BDE209 (25 mg∙L-1) could be degraded to penta-BDEs to diphenyl ether (DE) by 3.0 g∙L-1 OA-Fe/Pd within 240 min under neutral condition. This study provides some inspiration for improving the removal efficiency of PBDEs with nZVI-based materials.


Assuntos
Ecossistema , Nanopartículas Metálicas , Éteres Difenil Halogenados/análise , Humanos , Compostos de Magnésio , Compostos de Silício
2.
Environ Sci Pollut Res Int ; 29(3): 4461-4473, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34405333

RESUMO

Organic palygorskite (OP)-supported Pd/Fe nanoparticles composite (OP-Pd/Fe) was prepared by stepwise reduction method. The removal capacity of 4,4'-dibrominated diphenyl ether (BDE15) by OP-Pd/Fe was compared with other various materials. For better understanding the possible mechanism, the synthesized and reacted OP-Pd/Fe materials were characterized by TEM, SEM, XRD, and XPS, respectively. The effects of major influencing parameters on the degradation of BDE15 were also studied. Benefit from the synergistic effect of the carrier and bimetallic nanoparticles, BDE15 could be completely debrominated into diphenyl ether (DE) under suitable conditions. A two-stage adsorption/debromination removal mechanism was proposed. The degradation of BDE15 with OP-Pd/Fe was mainly stepwise debromination reaction, and hydrogen transfer mode was assumed as the dominated debromination mechanism. The removal process fitted well to the pseudo first-order kinetic equation. The observed rate constants increased with increasing Pd loading and OP-Pd/Fe dosage while decreased with increasing initial BDE15 concentration, the tetrahydrofuran/water ratio, and the initial pH of the solution. The work provides a new approach for the treatment of PBDEs pollution.


Assuntos
Ferro , Nanopartículas , Éteres Difenil Halogenados , Compostos de Magnésio , Compostos de Silício
3.
Chemosphere ; 288(Pt 1): 132491, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34624352

RESUMO

Phthalic acid esters (PAEs) are used as plasticizer or modifier in artificially-manufactured products. Though the rapid biotransformation of phthalates in microbes and plants have been well documented, it is less studied yet in terrestrial animals, e.g. earthworm. In this study, the major biotransformation of diethyl phthalate (DEP) in Eisenia fetida was illustrated using in vitro incubation of earthworm crude enzymes. DEP could be substantially biotransformed into phthalate monoester (MEP) and a small amount of phthalic acid (PA) through esterolysis, which was verified to be driven by endogenous carboxylesterase. Despite the inferior contribution, the oxidation of DEP might also occur under the initiated electron transfer by NADPH coenzyme. The dominant metabolite MEP showed a higher inhibition of superoxide dismutase (SOD) activity than DEP with EC50 of 0.0082 ± 0.0016 mmol/L, so the higher ecological risks of MEP would be marked. The inhibition effect of PA was validated to be even stronger than MEP though it was slightly generated. The direct binding interaction with SOD was proved to be an important molecular event for regulation of SOD activity. Besides the static quenching mechanism, the caused conformational changes including despiralization of α-helix and spatial reorientation of tryptophan were spectrally believed to affect binding and underlie inhibition efficiency of SOD activity.


Assuntos
Oligoquetos , Ácidos Ftálicos , Animais , Biotransformação , Ésteres , Oligoquetos/metabolismo , Plastificantes , Superóxido Dismutase/metabolismo
4.
J Hazard Mater ; 416: 126132, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492924

RESUMO

Polybrominated diphenyl ethers (PBDEs) are a group of persistent pollutants in the environment. Though aerobic biodegradation of PBDEs have been extensively studied, the involved hydroxylation mechanism decisive for whole biotransformation is not clear yet. During the effective biodegradation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) by B. xenovorans LB400, the depletion of endogenous ∙OH by scavenger could bring about the significant decrease of biodegradation efficiency whereas ·O2- was nearly not influential. Given the importance of ∙OH in hydroxylation, the reaction mechanisms along major pathways of electrophilic addition and hydrogen abstraction were theoretically examined by density functional theory (DFT). For the less demand of activation energy, the relative preference of electrophilic addition was shown at aromatic C3-site. When the secondary reaction was considered after addition at C4-site, the barrierless association of ∙OH at C3-site and deprotonation by H2O was validated as the energetically-favorable pathway that may cause dihydroxylation of BDE-47 into 3,4-dihydroxyl-BDE-17. The electrophilic addition followed by seconary barrierless trans-association of ∙OH and then dehydration seemed favorable for monohydroxylation as regards energetic barrier merely up to 194.01 kJ mol-1, while the hydrogen abstraction by ∙OH from C5-site was more privileged actually. The theoretical insights would help well understand the hydroxylation mechanism of PBDEs by aerobes.


Assuntos
Bactérias Aeróbias , Éter , Éteres Difenil Halogenados , Hidroxilação
5.
Ecotoxicol Environ Saf ; 223: 112559, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34333384

RESUMO

Phthalic acid esters (PAEs) are a group of widespread persistent organic pollutants in the environment. Though the harmful effect of PAEs including activity inhibition of superoxide dismutase (SOD) to arouse oxidative stress were well documented, the deep insights into mechanisms that are relevant with SOD activity are still lacking. By 7d-cultivation of Eisenia fetida in artificially-polluted soil, the different active responses of SOD in earthworm were shown to PAE congeners. Despite the less bioaccumulation and bioavailability, the di-butyl phthalate (DBP) etc. structurally coupled with longer ester-chains appeared more effective to trigger the up-regulation and then the slight decline of SOD activity. Given the remarkable biotransformation especially for short-chain PAEs, the SOD activity response in earthworm should be regarded as joint effect with their metabolites, e.g. monophthalates (MAEs) and phthalic acid (PA). The in vitro SOD activity was shown with the obvious inhibition of 21.31% by DBP, 88.93% by MBP, and 58.57% by PA respectively when the concentrations were elevated up to 0.03 mM. The SOD activity inhibition confirmed the molecular binding with pollutants as an essential event besides the biological regulation for activity. The binding interaction was thermodynamically exothermic, spontaneous and strengthened primarily by Van der Waals force and hydrogen bonds, and was spectrally diagnosed with the conformational changes including diminution of α-helix content and spatial reorientation of fluorophore tryptophan. As coherently illustrated with the larger fluorescence quenching constants (3.65*104-4.47*104/mol) than DBP, the metabolites should be the priority concern due to stronger activity inhibition and toxicological risks.


Assuntos
Oligoquetos , Ácidos Ftálicos , Poluentes do Solo , Animais , Dibutilftalato/toxicidade , Ésteres , Ácidos Ftálicos/toxicidade , Poluentes do Solo/toxicidade , Superóxido Dismutase
6.
Environ Sci Technol ; 55(6): 3676-3685, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33625846

RESUMO

Plastic films have become an integral part of fruit and vegetable production systems, but their release of phthalate acid esters (PAEs) is a threat to human health. The release kinetics of PAEs and measures of risk are still not well understood. We investigated 50 agricultural films, with concentrations ranging from 2.59 to 282,000 mg kg-1. The seven commercially available film types included were polyvinylchloride (PVC), metallocene polyethylene (mPE), ethylene vinyl acetate (EVA), polyolefin (PO), and three mulch films. Bis(2-ethylhexyl) phthalate (DEHP) was detected in most of films, and its release fitted well into the first-order kinetic model. The release rate of DEHP was negatively related to the film thickness. The potential carcinogenic risks of DEHP in the air of six kinds of plastic greenhouses to human health were estimated. We found that the carcinogenic risks associated with PVC and mPE greenhouse films warrant greater attention. Though EVA, PO greenhouse, and mulch films were lower risk, we advise keeping plastic greenhouses well ventilated during the first month of use to reduce direct human exposure to volatile PAEs.


Assuntos
Dietilexilftalato , Ácidos Ftálicos , Poluentes do Solo , China , Dibutilftalato , Ésteres , Humanos , Cinética , Plásticos , Medição de Risco , Poluentes do Solo/análise
7.
Environ Int ; 144: 105995, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32758715

RESUMO

The combined effects of biochar amendment and the rhizosphere on the soil metabolic microbiome during the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soil remain unknown. In this study, we attempted to characterize a PAH degradation network by coupling the direct PAH degradation with soil carbon cycling. From microbial community structure and functions to metabolic pathways, we revealed the modulation strategies by which biochar and the rhizosphere benefited PAH degradation in soil. Firstly, some PAH degraders were enriched by biochar and the rhizosphere, and their combination promoted the cooperation among these PAH degraders. Simultaneously, under the combined effects of biochar and the rhizosphere, the functional genes participating in upstream PAH degradation were greatly upregulated. Secondly, there were strong co-occurrences between soil microbial community members and metabolites, in particular, some PAH degraders and the metabolites, such as PAH degradation products or common carbon resources, were highlighted in the networks. It shows that the overall downstream carbon metabolism of PAH degradation was also greatly upregulated by the combined effects of biochar and plant roots, showing good survival of the soil microbiome and contributing to PAH biodegradation. Taken together, both soil carbon metabolism and direct contaminant biodegradation are likely to be modulated by the combined effects of biochar and plant roots, jointly benefitting to PAH degradation by soil microbiome. Our study is the first to link PAH degradation with native carbon metabolism by coupling sequencing and soil metabolomics technology, providing new insights into a systematic understanding of PAH degradation by indigenous soil microbiome and their networks.


Assuntos
Microbiota , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Biodegradação Ambiental , Carvão Vegetal , Metabolômica , Hidrocarbonetos Policíclicos Aromáticos/análise , Solo , Microbiologia do Solo , Poluentes do Solo/análise
8.
Chemosphere ; 249: 126554, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32213394

RESUMO

Polybrominated diphenyl ethers (PBDEs) are more frequently suspected with the induction of toxicity via signal transduction pathway of cytosolic aryl hydrocarbon receptor (AhR), the initial binding to which is assumed to be an essential prerequisite during the ligand-dependent activation. However, the AhR binding property and associated toxicity of PBDEs is yet to be clearly known for lacking insights into the structural requirements at molecular level. To understand the AhR binding property of PBDEs, the ligand binding domain (LBD) of AhR was simulatively developed on homologous protein after basic validation of geometrical rationality and the binding interaction profile was visually described using molecular docking approach. For AhR binding, the offset or edge-on π-π stackings with aromatic motifs including Phe289, Phe345 and His285 were shown to be structurally required whereas the electrostatic attraction validated for AhR binding to dioxins might be less effective for 2,2',3,4,4'-pentabromodiphenyl ether (BDE-85). Besides the demands of less steric hindrance from alanines and weak formulation of hydrogen bonds, the dispersion force through large contact and polarization of S-π electrons seemed to be impactful when BDE-85 were closer to Cys327, Met334 or Met342. With theoretical computation of AhR binding energies, the more significant correlativity with bioassays was derived especially for the lowly/moderately brominated congeners, and could be used to predict the AhR binding affinity on certain degree. The informative results would thus not only help well understand the molecular basis of AhR-mediated toxicity but give an approach for accelerative evaluation of AhR binding and toxicity of PBDEs.


Assuntos
Poluentes Ambientais/toxicidade , Éteres Difenil Halogenados/toxicidade , Receptores de Hidrocarboneto Arílico/metabolismo , Bioensaio , Éteres Difenil Halogenados/metabolismo , Humanos , Ligação de Hidrogênio , Ligantes , Simulação de Acoplamento Molecular , Bifenil Polibromatos/farmacologia , Ligação Proteica , Transdução de Sinais/efeitos dos fármacos
9.
J Hazard Mater ; 393: 122382, 2020 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-32114132

RESUMO

Microbiological degradation is often considered as an important strategy to reduce the risks of polybrominated diphenyl ethers (PBDEs), which are environmentally widespread and harmful to human health and wildlife. With the well-identified aerobic bacteria, i.e. B. xenovorans LB400, the biodegradation of 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47) occurred efficiently in conformity to the first-order kinetics and showed the strong dependence on initial concentration of pollutant and bioavailability regulation by biosurfactant. The mild increase of initial concentration of BDE-47 would enhance biodegradation whereas the excessive increase failed due to the oxidative stress or cytotoxicity to bacteria. Rather than the bacterial extracellular adsorption that was bioactively-mediated in thermodynamics, the intracellular accumulations at different time gradients showed the negative correlation with biodegradation efficiency of BDE-47. The spontaneous biodegradation of pollutant should be sourced from the gradual reduction of intracellular accumulation. Though the improved bioavailability of BDE-47 by sucrose fatty acid ester (SFAE) hardly altered the extracellular adsorption, the bacterial intracellular accumulation was indicated to increase continuously with used amount of biosurfactant and then decrease for the cellular morphological damage, and interestingly it appeared to be temporary reservoir for prompt delivery to biodegradation in light of the opposite variation tendency with time.


Assuntos
Burkholderiaceae/química , Burkholderiaceae/metabolismo , Éteres Difenil Halogenados/química , Éteres Difenil Halogenados/metabolismo , Adsorção , Biodegradação Ambiental , Disponibilidade Biológica , Ésteres/química , Tensoativos/química
10.
Environ Res ; 179(Pt B): 108838, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31678730

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) which are structurally featured with one or more aromatic skeletons are often regarded as two important groups of organic pollutants due to the widespread distribution and notorious toxic effects in soils. Relative to the great number of structural analogues or congeners detected in soil, however, the soil adsorption and bioaccumulation of PAHs/PAEs by plant is far less studied for the insufficiency of experimental determinations or lack of insights into the inherent structural requirements. To mechanistically evaluate the congener-specific soil adsorption and bioaccumulation for PAHs/PAEs, the quantitative structure-activity relationships (QSARs) were successfully developed by density functional theory (DFT) computation and partial least squares (PLS) analysis. As verified with the higher cumulative variance coefficients and cross-validated correlation coefficients for strong stability, interpretability and predictability, the QSARs could be used for prediction of unknown adsorption potency or bioavailability within the specified applicability domain, respectively. It was indicated by QSAR that the structural requirements of PAHs/PAEs necessary for strengthening the soil adsorption were mainly attributed to the molecular polarizability and the associated dispersion interaction with soil. As regards the bioaccumulation by carrot, the aggravation of spherical polarity change of molecules and the involved electrostatic interaction with soil entity or electron transfer from the highest occupied molecular orbital (HOMO) of PAHs/PAEs was implied to be inherently decisive for the variance of bioavailability among congeners. Based on the holistic view of negative correlation relationship, the soil adsorption seemed to act as the forceful constraint in decreasing the bioaccumulation of PAHs/PAEs and could also be alternatively gauged as the preliminary evaluation of bioavailability and risks on soil ecosystem. It would thus help better understand the soil adsorption and bioaccumulation with the informative mechanistic insights and provide data support for ecological risk assessment of PAHs/PAEs in soils.


Assuntos
Ácidos Ftálicos/química , Hidrocarbonetos Policíclicos Aromáticos/química , Relação Quantitativa Estrutura-Atividade , Poluentes do Solo/química , Adsorção , Bioacumulação , Ecossistema , Ácidos Ftálicos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Solo , Poluentes do Solo/análise
11.
Environ Pollut ; 255(Pt 2): 113312, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31610503

RESUMO

Polycyclic aromatic hydrocarbons (PAHs), some of the most widespread organic contaminants, are highly toxic to soil microorganisms. Whether long-term polluted soils can still respond to the fresh input of pollutants is unknown. In this study, the soil enzyme activity, soil microbial community structure and function and microbial metabolism pathways were examined to systematically investigate the responses of soil microorganisms to fresh PAH stress. Microbial activity as determined by soil dehydrogenase and urease activity was inhibited upon microbe exposure to PAH stress. In addition, the soil microbial community and function were obviously shifted under PAH stress. Both microbial diversity and richness were decreased by PAH stress. Rhizobacter, Sphingobium, Mycobacterium, Massilia, Bacillus and Pseudarthrobacter were significantly affected by PAH stress and can be considered important indicators of PAH contamination in agricultural soils. Moreover, the majority of microbial metabolic function predicted to respond to PAH stress were affected adversely. Finally, soil metabolomics further revealed specific inhibition of soil metabolism pathways associated with fatty acids, carbohydrates and amino acids. Therefore, the soil metabolic composition distinctively changed, reflecting a change in the soil metabolism. In summary, fresh contaminant introduction into long-term polluted soils inhibited microbial activity and metabolism, which might profoundly affect the whole soil quality.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Agricultura , Biodegradação Ambiental , Poluentes Ambientais , Metabolômica , Microbiota , Hidrocarbonetos Policíclicos Aromáticos/análise , Solo/química , Poluentes do Solo/análise
12.
Sci Total Environ ; 695: 133879, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31425980

RESUMO

It remains unclear whether biochar amendment can mediate changes in soil microbial communities caused by organic contaminants in the rhizosphere. In this study, phenanthrene-contaminated soil was amended with biochar and oxalic acid (OA) alone or in combination and incubated for 21 days. Phospholipid fatty acids (PLFAs) and high-throughput sequencing were used to evaluate shifts in bacterial and fungal community structure. Phenanthrene stress led to significant shifts in both soil bacterial and fungal community structure, in particularly, 82% of microbial phyla decreased in abundance. Biochar and/or OA improved the phenanthrene-polluted soil by positively mediating shifts in soil microbial communities stressed by phenanthrene. Specifically, biochar and/or OA led to the survival of certain microbial taxa that were inhibited by phenanthrene stress. In addition, many functional microbial individuals and genes participating in polycyclic aromatic hydrocarbon (PAH) degradation were positively stimulated by high phenanthrene stress and further stimulated by the simultaneous application of biochar and OA. Based on these findings, tandem biochar and rhizoremediation may be a feasible strategy for relieving PAH toxicity to soil microbial communities.


Assuntos
Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Ácido Oxálico/química , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Biodegradação Ambiental , Microbiota
13.
Bull Environ Contam Toxicol ; 103(4): 642-650, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31428843

RESUMO

In this study, the responses of soil bacterial communities to biochar amendment in different soils were investigated. Biochar amendment had not significantly changed the bacterial richness and diversity in black soil, fluvo-aquic soil and red soil, but shifted all the soil bacterial community structures. Biochar amendment mainly increased the growth of low-abundance bacteria in fluvo-aquic soil and that of high-abundance bacteria in red soil. The most abundant bacterial phylum in black soil and fluvo-aquic soil, Proteobacteria, increased after biochar addition, while Chloroflexi, the most abundant phylum in red soil, decreased after biochar addition. Some bacterial phyla responded consistently to biochar amendment. However, many more bacterial phyla responded differently to biochar amendment in different soils, especially those phyla present at low abundances. Therefore, our study confirmed that the responses of soil bacterial communities to the same biochar were specific to both soil type and bacterial phylum.


Assuntos
Carvão Vegetal , Microbiologia do Solo , Bactérias , Microbiota , Solo/química , Poluentes do Solo/análise
14.
Sci Total Environ ; 681: 392-399, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31108359

RESUMO

There is urgent demand for the design of advanced coating materials for solid-phase microextraction (SPME) for water quality monitoring and assessment because of the global occurrence of chlorobenzenes (CBs). In this study, we proposed a dual-order activation method in which potassium hydroxide is used to modify pre-activated calcium citrate to synthesize a highly developed meso-/microporous carbon (MMC). The as-obtained MMC presented well-developed porosity with a super-high specific surface area (2638.09 m2 g-1), abundant meso-/micropores (0.5-10 nm), high hydrophobicity, excellent thermal stability (>720 °C), and a partly graphitized structure. As a coating material for headspace-SPME, the MMC-coated fiber exhibited outstanding extraction capability for CBs (up to 48.5 times higher than that of commercial fibers), which may be attributed to multiple interactions between the MMC and the pollutants, including size selectivity, micropore filling, π-π stacking and hydrophobicity. Finally, a satisfactory method using an MMC-coated fiber coupled with gas chromatography and electron capture detection was developed with good linearity (1-1000 ng L-1, R2 > 0.9982), high enrichment efficiencies (enrichment factors, 861-7819), low limits of detection (0.003-0.072 ng L-1), excellent repeatability (0.7-5.3%) and reproducibility (1.7-5.1%), and outstanding recoveries (90.18-103.02%) when applied to determine trace CBs in real water samples. These results suggest that MMC is a promising coating material for the SPME of CBs.

15.
J Hazard Mater ; 374: 341-348, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31026627

RESUMO

Biochar application to soil is recognised for its capacity to immobilise pollutants (through sorption) while composted inputs can accelerate the biodegradation of organic pollutants. However, little is known about the influence of combined incorporation on plant uptake of organic pollutants. Therefore, we investigated the effects of maize straw-derived biochar (MSB), compost derived from maize straw and pig manure (SMC), and their combination (MSB-SMC) as soil amendments on bioavailability of 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47) and carrot (Daucus carota L.) uptake in a horticultural soil. We found that biochar alone performed well in reducing BDE-47 bioavailability, but was less effective at degrading the pollutant. Conversely, addition of compost stimulated BDE-47 biodegradation. MSB-SMC enhanced BDE-47 biodegradation in soil, reduced contamination of carrot roots, and caused significant reductions in soil extractable BDE-47. The combination of contrasting approaches to remediation thus resulted in the most favorable outcome for a contaminated soil: immobilisation of contaminant from vegetable crops (via biochar) with simultaneous bioremediation of the growing medium. These findings point towards an effective strategy for reducing plant uptake of PDBEs through the combined use of biochar and compost as soil amendment - reducing mobility and facilitating degradation of the accessible contaminant fractions.


Assuntos
Carvão Vegetal/química , Compostagem , Poluição Ambiental , Éteres Difenil Halogenados/metabolismo , Poluentes do Solo/metabolismo , Animais , Biodegradação Ambiental , Disponibilidade Biológica , Produtos Agrícolas , Daucus carota , Esterco , Microbiota , Raízes de Plantas , Brotos de Planta , Solo , Suínos , Zea mays/metabolismo
16.
Bioresour Technol ; 284: 1-8, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30925418

RESUMO

In this study, rape straw- and corn cob-derived porous carbons (PCs) were fabricated by hydrothermal treatment (250 °C, 4 h) and subsequent activation (850 °C, 1 h) using a non-corrosive agent, potassium bicarbonate. The PCs exhibited a very large specific surface area (1069-1281 cm2 g-1), high pore volume (0.55-0.72 cm3 g-1), wide pore size distribution (from micropores to macropores), high hydrophobicity, and partly graphitized structure. These properties contributed to highly efficient performance for the sorption of polycyclic aromatic hydrocarbons (PAHs), with maximum sorption capacities of 592.97, 480.27, and 692.27 mg g-1 towards naphthalene, acenaphthene, and phenanthrene, respectively. A three-step sorption process with pore filling, hydrophobic effects, and π-π stacking interactions on the heterogeneous surface is a possible mechanism for the sorption of PAHs onto PCs. This study presents an environmentally friendly strategy for the reuse of crop residues in the field of organic micropollutant-contaminated water treatment.


Assuntos
Carbono/química , Naftalenos/isolamento & purificação , Fenantrenos/isolamento & purificação , Poluentes Químicos da Água/química , Água/química , Adsorção , Interações Hidrofóbicas e Hidrofílicas , Cinética , Porosidade
17.
Chemosphere ; 214: 408-417, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30268896

RESUMO

Polybrominated diphenyl ethers (PBDEs) have been regarded as ubiquitous environmental pollutants. However, the absorption and transformation of these compounds after ingestion are not well understood yet. In this study, the bioaccessibility and metabolic pathway of 2,2',4,4'- tetrabromodiphenyl ether (BDE47) was investigated in an in vitro digestion/Caco-2 cell. Gastric and intestinal bioaccessibilities of BDE47 in 5 kinds of spiked soil samples were ranging from 11.39 ±â€¯0.83% to 36.02 ±â€¯4.34%, and 48.24 ±â€¯3.24% to 81.52 ±â€¯6.43%, respectively. Upon exposure to differentiated Caco-2 cells for 6 h, it was found that only a small amount of BDE47 in the gastrointestinal (GI) solution could pass through Caco-2 cells, and might enter the body. Moreover, BDE47 was found to be metabolized or transformed into BDE28, BDE75, BDE37, BDE32, BDE15 and BDE8 in Caco-2 cells. The metabolic pathway could be explained by using the Becke three-parameter hybrid functional (B3Lucifer yellow CHP) in the Density Functional Theory (DFT), denoted as the values of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) at the atoms of BDE47 and its metabolic products. The obtained results suggest that oral intake of PBDEs is associated with low bioaccessibility, but also emphasize the risks associated with oral ingestion, namely toxicity resulting from the debromination of highly brominated diphenyl ethers. Although highly brominated diphenyl ethers are known to be the least toxic PBDEs, the debrominated products in human intestinal epithelia may elicit greater than expected toxicity.


Assuntos
Trato Gastrointestinal/metabolismo , Éteres Difenil Halogenados/farmacocinética , Poluentes do Solo/farmacocinética , Disponibilidade Biológica , Células CACO-2 , Humanos , Distribuição Tecidual
18.
Chemosphere ; 214: 176-183, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30265924

RESUMO

Extracellular polymeric substances (EPS), chars and persistent organic pollutants (POPs) frequently coexist in the environment. However, a knowledge gap exists regarding their interactions. Therefore, we applied 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) as a model POP to investigate the influence of bovine serum albumin (BSA) and sodium alginate (SA) - representing protein and polysaccharide components of EPS - on POP adsorption to biochars. Surface activities of tested biochars were characterised using nuclear magnetic resonance, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The adsorption capacities of BDE-47 on biochars were significantly improved by both EPS analogues: BSA at concentrations of only 5 mg L-1 and SA at 80 mg L-1 at ce = 1 Sw BDE-47 concentration. However, 80 mg L-1 BSA decreased the BDE-47 adsorption capacities on biochars at the tested BDE-47 concentrations. Chemisorption and pore filling mechanisms appeared to dominate the adsorption process of BDE-47 on maize straw and wheat straw biochars. After adding BSA (or SA), a hydrophobic partition effect was found to best explain the adsorption process and linearity of adsorption was enhanced. These results progress our understanding of bioavailability and migration of POPs: especially relevant to the water industry and biochar/EPS facilitated removal of these contaminants.


Assuntos
Adsorção , Alginatos/química , Carvão Vegetal/química , Matriz Extracelular de Substâncias Poliméricas/química , Éteres Difenil Halogenados/química , Soroalbumina Bovina/química , Modelos Químicos , Compostos Orgânicos/química , Análise Espectral , Triticum , Poluentes Químicos da Água/química , Purificação da Água/métodos , Zea mays
19.
Chemosphere ; 210: 941-948, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30208554

RESUMO

Though bioaccessibility commonly recognized as a guideline for risk assessment is closely related with pollution occurrence and chemical species of compounds, the mechanistic links are barely evaluated particularly for widespread polychlorinated biphenyls (PCBs) in soil. With the biomimetic extraction of hydroxypropyl-ß-cyclodextrin (ß-HPCD), the temporal and spatial influences of soil properties, aging and structural characteristics, e.g. polarity of PCB congeners on bioaccessibility were investigated for PCBs. Sensitive variation of bioaccessibility with aging, soil organic matter (SOM), particle size and soil moisture were clearly evidenced for different PCB congeners. Due to aging, the bioaccessibility decreased in the long term after stabilization for 36 h. In concert with the first-order kinetics, the decay rates of bioaccessibility were shown with congener-specificity and were well correlated with dipoles of PCBs. The increment of SOM diminished the bioaccessibility for the strengthened adsorption while the increased particle size and soil moisture elevated it possibly due to the less adsorption on soil particles and more accommodation of PCBs in soil pore water. Except the positive correlations with particle size, soil moisture and dipole moment, the greater dependency on aging and SOM was highlighted for bioaccessibility by partial least squares (PLS) analysis. The mutual relationship with influential factors was quantitatively formulated for accelerative prediction of bioaccessibility, and the comparative evaluation and detailed insights into the mechanistic links would thus help enhance the precise determination of bioaccessibility and risk assessment of PCBs in soil.


Assuntos
Poluição Ambiental/análise , Bifenilos Policlorados/química , Poluentes do Solo/química , Solo/química , Bifenilos Policlorados/análise , Poluentes do Solo/análise
20.
J Agric Food Chem ; 66(34): 8941-8948, 2018 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-30091910

RESUMO

Plastic greenhouse vegetable cultivation (PGVC) has been widely developed around the world and has resulted in great changes in soil properties and potential contamination by phthalate esters (PAEs). Using high-throughput sequencing, this study investigated the succession and potential factors impacting soil microbial community structures over 20 years of PGVC. The results showed that the pH of soils under PGVC were significantly lower, while the nutrient contents of soils were higher, relative to those of open field soil. The residue concentrations of PAEs in soil under PGVC increased with increasing periods of PGVC. The fungal community diversity, rather than the bacterial community diversity, was significantly reduced in soils under PGVC. However, both the soil bacterial and fungal community structures were changed by long-term PGVC. Among the tested soil physicochemical properties, soil pH and clay were the top two factors affecting the soil bacterial community, while pH and phosphorus (P) mainly affected the soil fungal community structures. No relationship between the changes of microbial communities and PAE residues in soil was observed. This study indicates that the soil acidification and nutrient accumulation under PGVC mainly shifted the changes of soil microbial community structures, which could occur after only 5 years of PGVC.


Assuntos
Agricultura/instrumentação , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Plásticos/farmacologia , Microbiologia do Solo , Poluentes do Solo/farmacologia , Agricultura/métodos , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Plásticos/análise , Solo/química , Poluentes do Solo/análise , Verduras/crescimento & desenvolvimento
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