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1.
Sci Total Environ ; 751: 142235, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-33181987

RESUMO

Inhaled particulate matter (PM) from combustion- and friction-sourced air pollution adversely affects organs distant from the lung. A putative mechanism for the remote effect of inhaled PM is that ultrafine, nano-sized fraction (<100 nm) translocates across the air-tissue barrier, directly interacting with phagocytic tissue cells. Although PM is reported in other tissues, whether it is phagocytosed by non-respiratory tissue resident cells is unclear. Using the placenta as an accessible organ for phagocytic cells, we sought to seek evidence for air pollution-derived PM in tissue resident phagocytes. Macrophage-enriched placental cells (MEPCs) were isolated, and examined by light and electron microscopy. MEPC carbon was assessed by image analysis (mean µm2/1000 cells); particle composition and numbers were investigated using magnetic analyses and energy dispersive X-ray spectroscopy. MEPCs phagocytic capacity was assessed by culture with diesel exhaust PM in vitro. Fifteen placentas were analysed. Black inclusions morphologically compatible with inhaled PM were identified within MEPCs from all samples (mean ± SEM carbon loading, 1000 MEPCs/participant of 0.004 ± 0.001 µm2). High resolution scanning/transmission electron microscopy revealed abundant nano-sized particle aggregates within MEPCs. MEPC PM was predominantly carbonaceous but also co-associated with a range of trace metals, indicative of high temperature (i.e. exogenous) generation. MEPCs contained readily-measurable amounts of iron-rich, ferrimagnetic particles, in concentrations/particle number concentrations ranging, respectively, from 8 to 50 ng/g and 10 to 60.107 magnetic particles/g (wet wt) MEPCs. Extracted MEPCs (n = 20/ placenta) were phagocytic for PM since all cells showed increased carbon area after culture with diesel PM in vitro (mean ± SEM increase 7.55 ± 1.26 µm2 carbon PM). These findings demonstrate that inhaled, metal-bearing, air pollution-derived PM can not only translocate to distant organs, but is taken up by tissue resident phagocytes in vivo. The human placenta, and hence probably the fetus, thus appears to be a target for such particles.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Nanopartículas , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Poluição do Ar/análise , Feminino , Humanos , Tamanho da Partícula , Material Particulado/análise , Gravidez , Emissões de Veículos/análise , Emissões de Veículos/toxicidade
2.
Sci Total Environ ; 752: 141936, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32889289

RESUMO

Although nanoplastics (NPs) are known to be toxic to several groups of animals, the effects of such a toxicity on freshwater benthic macroinvertebrate communities remain unknown. Thus, the aim of the current study is to test the hypothesis that polystyrene nanoplastics (PS NPs) (34 µg/L - 48 h of exposure) lead to biochemical damage in Aphylla williamsoni larvae. Data have evidenced high bioaccumulation factor in the analyzed individuals; this finding indicates that, similar to sediments, water is also part of aquatic systems and favors PS NPs retention in dragonfly larvae. Despite the lack of evidence about the interference of these pollutants in the nutritional status of the analyzed animals, their bioaccumulation was associated with REDOX imbalance featured by concomitant increase in the number of evaluated oxidative stress biomarkers (nitric oxide and lipid peroxidation) and antioxidants (antioxidant activity against the DPPH radical and the superoxide dismutase enzyme). On the other hand, the reduced acetylcholinesterase activity observed in larvae exposed to PS NPs has suggested the neurotoxic effect of these pollutants, with potential impact on their nerve and neuromuscular functions. Therefore, the current study is pioneer in showing that PS NPs can affect the health of the investigated larvae, even at small concentrations, for short exposure-time; this outcome reinforces the ecotoxicological risk of these pollutants for freshwater benthic macroinvertebrates.


Assuntos
Poluentes Ambientais , Nanopartículas , Odonatos , Poluentes Químicos da Água , Animais , Humanos , Larva , Microplásticos , Nanopartículas/toxicidade , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade
3.
Sci Total Environ ; 752: 141878, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32890834

RESUMO

BACKGROUND: Larval zebrafish (Danio rerio) is not only an ideal vertebrate applied in Fish Embryos Toxicity (FET) test but also a well-accepted model in behavioral neurotoxicity research. By applying the commercial standard behavioral tracking system (Zebrabox), the locomotion profiles (neurobehavioral-phenomics) of larval zebrafish can be comprehensively monitored and systematically analyzed to probe ecotoxicological neurotoxicity of nano-pollutants at environmental relevant concentration level. RESULTS: Herein, the potential toxicity of at environment relevant concentration level on embryonic zebrafish was evaluated by FET and neurobehavioral-phenomics (NBP). The embryos were exposed to the environmental relevant concentration (0.05, 0.1,1, 5, 10, 100 µg/L). The FET criteria were utilized to evaluate the ecotoxicological effect induced by silica NPs. Subsequently, behavioral neurotoxicity of silica NPs was further quantified via locomotion response (LMR). Specifically, the alteration of Light/Dark challenge (LDC) evoked by light/dark stimulation was detected and analyzed by commercially standard behavioral protocols using zebrabox. We revealed that the exposures of silica NPs at environmental relevant concentration (0.05, 0.1, 1, 5, 10,100 µg/L) significantly disturbed locomotion profiles of larval zebrafish. Additionally, it was obviously noted that low, environmentally relevant silica concentrations might result in altering the total behavioral profiles in developing zebrafish. CONCLUSIONS: In sum, neurobehavior phenomics profiling based on LMR and LDC is a potent methodology for the evaluation of sub-lethal or sub-teratogenic toxicity. Compared with the FET tests characterized by the detection of embryonic teratogenicity, the neurobehavior phenomics based method can be more sensitive to determine sub-teratogenic toxicity of silica NPs at environmental concentrations. With the combination of multivariate data analysis, this approach would offer effective technical reference for environmental nano-toxicology research.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Animais , Comportamento Animal , Embrião não Mamífero , Larva , Fenômica , Dióxido de Silício/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
4.
Sci Total Environ ; 753: 141743, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32891989

RESUMO

Nickel oxide nanoparticles (NiO-NPs) have extensively used in industrial and consumer products. The present study conducted to gain more knowledge about the safe use of NiO-NPs and also to understand their impact on the environment and biological systems. Herein, we examined the genotoxic and ultra-structural effects of a sublethal dose of NiO-NPs (0.03 mg/g) on the ovarian tissues of the ground beetle, Blaps polycresta. The mean diameter of NiO-NPs was 24.49 ± 3.88 nm, as obtained through transmission electron microscopy (TEM). In terms of DNA damage levels, the frequency of micronucleus (MN) formation was highly significant in the NiO-NPs treated group versus the controls. Besides, NiO-NPs treatment resulted in a significant increase in the tail length of comets. Further, electron microscopy revealed a progressive increase in chromatin condensation of the ovarian nurse and follicular cells, in addition to the accumulation of lysosomes and endo-lysosomes in their cytoplasm. In conclusion, NiO-NPs are capable of gaining access to the ovary of B. polycresta and causing DNA damage and a high degree of cellular toxicity in the ovarian cells. The present study highlights, for the first time, the adverse effects of these NPs to female gonads of insects and raised the concern of its genotoxic potential. It would be of interest to investigate NiO-NPs mediated intracellular ROS generation in future studies.


Assuntos
Besouros , Nanopartículas Metálicas , Nanopartículas , Animais , Dano ao DNA , Feminino , Nanopartículas Metálicas/toxicidade , Níquel/toxicidade
5.
Chemosphere ; 262: 127854, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799148

RESUMO

Plastic nanoparticles (PNPs) are considered contaminants of emerging concern, but little information is available on their transport behavior in the soil-water environment, as well as their behavior relative to metal and other carbon-based nanoparticles. Here we show that size and surface functional groups affect the transport of polystyrene nanoparticles (PS-NPs) through saturated soil. Unmodified 110 nm and 50 nm PS-NPs demonstrated similar transport patterns in soil. However, a maximum elution value of 90% from the soil was found for the 50 nm PS-NPs, compared to a maximum value of ∼45% for 110 nm PS-NPs. The breakthrough curve for 190 nm PS-NPs demonstrated a maximum elution value of 60% from the soil. PS-NPs with surface functional groups display different mobility profiles: carboxylated PS-NPs demonstrated a plateau of 40% elution from the soil, while aminated PS-NPs were eluted only in small amounts and showed a spike pattern of elution from the column. These findings are attributed to the effects of common soil constituents such as calcium cations and humic acids on the size and charge of the PS-NPs with surface functional groups. Overall, PS-NP mobility in soil can vary widely, depending on PNP properties such as size and surface chemistry, and on matrix properties, such as the type of porous medium and its composition. These findings suggest that knowledge of inherent characteristics (size, surface charge, surface functional groups) of PNPs are required to elucidate the behavior of such particles in soil-water environments, and predict the extent of contaminant spreading.


Assuntos
Microplásticos/química , Nanopartículas/química , Substâncias Húmicas , Tamanho da Partícula , Poliestirenos , Porosidade , Solo/química
6.
Food Chem ; 336: 127597, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32763732

RESUMO

In this study, bacterial cellulose nanocrystals (BCNCs) were obtained from bacterial cellulose nanofibers (BCNFs) by controlled hydrolysis of sulfuric and hydrochloric acids. The influence of hydrolysis temperature and acid type with the addition of the post-treatment step was studied. The obtained BCNCs were analyzed based on the structural characterization and the properties of the nanocrystals. The BCNCs crystallinity increased, and the size of nanocrystals decreased with increasing 10 °C hydrolysis temperature for both acid hydrolysis conditions. Hydrolysis conditions with neutralization post-treatment did not alter the thermal stability of nanocrystals, and BCNCs had high thermal stability like raw BCNFs. Elemental analysis results indicated that sulfur content (S %) was very low for sulfuric acid hydrolyzed samples, and X-ray results did not show any sulfate salt peaks. Thermal stable BCNCs with high crystallinity were successfully produced to meet the process requirements in various applications, especially in the food industry.


Assuntos
Celulose/química , Ácido Clorídrico/química , Nanopartículas/química , Ácidos Sulfúricos/química , Bactérias/metabolismo , Hidrólise , Temperatura
7.
Food Chem ; 336: 127669, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32758804

RESUMO

Curcumin was recently attracted great interest owing to its multiple bioactivities; however, the use of curcumin was hindered by its poor solubility and stability. In this study, curcumin-nisin-soy soluble polysaccharide nanoparticles (Cur-Nisin-SSPS-NPs, size = 118.76 nm) have been successfully elaborated to improve the application of curcumin. The formation of Cur-Nisin-SSPS-NPs was mediated by amphiphilic and positively charged nisin: SSPS encapsulated nisin, which was mainly driven by electrostatic attraction. And nisin-SSPS complex encapsulated curcumin mainly through hydrophobic interactions between nisin and curcumin. The encapsulation efficiency of curcumin (91.66%) in this novel nanocarriers was significantly higher than that in nanoparticles prepared by a single SSPS (31.82%) or nisin (41.69%), most likely because more hydrophobic regions of nisin were exposed after interacting with SSPS through electrostatic interaction. Consequently, this facile and green nanocarriers improved the solubility/dispersibility and stability of curcumin and nisin, as well as endowed SSPS-based nanoparticles with antioxidant and antimicrobial activities.


Assuntos
Curcumina/administração & dosagem , Portadores de Fármacos/química , Nanopartículas/química , Nisina/química , Polissacarídeos/química , Antibacterianos/administração & dosagem , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Curcumina/química , Curcumina/farmacocinética , Liberação Controlada de Fármacos , Interações Hidrofóbicas e Hidrofílicas , Imidazóis , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Morfolinas , Solubilidade , Soja/química , Espectrofotometria Ultravioleta
8.
Food Chem ; 336: 127675, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32795781

RESUMO

The present study explores the biosorption potential of Pleurotus ostreatus immobilized magnetic iron oxide nanoparticles for solid-phase extractions of Ni(II) and Pb(II) ions from the water and food samples. It was characterized using FTIR, FE-SEM/EDX before and after analyte ions biosorption. Important operational parameters including the effect of initial pH, the flow rate of the sample solution and volume, amount of biomass and support material, interfering ions, best eluent, column reusability were studied. The biosorption capacities of fungus immobilized iron oxide nanoparticles were found as 28.6 and 32.1 mg g-1 for Ni(II) and Pb(II), respectively. The limit of detection (LOD) and limit of quantitation (LOQ) were achieved as 0.019 and 0.062 ng mL-1 for Ni(II), 0.041 and 0.14 ng mL-1 for Pb(II), respectively. The proposed method was validated by applying to certified reference materials and successfully applied for the preconcentrations of Ni(II) and Pb(II) ions from water and food samples by ICP-OES.


Assuntos
Chumbo/isolamento & purificação , Nanopartículas/química , Níquel/isolamento & purificação , Pleurotus/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Células Imobilizadas , Compostos Férricos/química , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Concentração de Íons de Hidrogênio , Limite de Detecção , Fenômenos Magnéticos , Níquel/química , Reprodutibilidade dos Testes , Extração em Fase Sólida/instrumentação , Poluentes Químicos da Água/química
9.
Food Chem ; 334: 127605, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32738726

RESUMO

Chitosan (Ch) and zinc oxide nanoparticles loaded gallic-acid films, (Ch-ZnO@gal) have been prepared aiming for their exploitation as environmentally benign food packaging material. The chitosan films with varying quantities of zinc oxide nanoparticles loaded gallic-acid (ZnO@gal) content were synthesized in order to evaluate the effect of ZnO@gal on their optimum mechanical and biological potential. The characteristic results have shown that the incorporation of ZnO@gal into chitosan films remarkably enhanced the desired mechanical property of the chitosan films. Other noticeable physical properties such as oxygen and water vapor permeability (WVP), swelling, water solubility and UV-vis light transmittance have also been found to improve positively. SEM analysis of the films indicates a good material compatibility between chitosan and ZnO@gal matrices. Ch-ZnO@gal films possess significant antibacterial potential and strong antioxidant behavior compared to pristine chitosan. The overall results suggested that the prepared biocomposite chitosan films may be considered for active food packaging applications.


Assuntos
Quitosana/química , Embalagem de Alimentos/métodos , Ácido Gálico/química , Nanopartículas/química , Óxido de Zinco/química , Antibacterianos/química , Antioxidantes/química , Bacillus subtilis/efeitos dos fármacos , Materiais Biocompatíveis/química , Escherichia coli/efeitos dos fármacos , Embalagem de Alimentos/instrumentação , Permeabilidade , Solubilidade , Vapor , Resistência à Tração , Raios Ultravioleta , Óxido de Zinco/farmacologia
10.
Food Chem ; 335: 127681, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32739803

RESUMO

In this study the Lagrange interpolation optimization algorithm based on two variables with respect to all experimental replicates (POA), was compared with two other heuristics methods (WOA and GOA). Modification of the apple surface by an edible nano coating solution in food packaging was used as case study. The experiment was performed as a factorial test based on completely randomized design by 100 permutations data sets. Results showed a significant difference between the three optimization methods (POA, WOA and GOA) which indicates the necessity of optimization and also efficiency of the present POA. The optimum result by POA, similar to a rose petal property, could rise 72% in surface contact angle (CA). The scanning electron microscopy (SEM) images of the derived surfaces showed almost a uniform spherical nanoparticles morphology. Remarkable advantages of this new approach are no additional material requirement, healthful, easy, inexpensive, fast and affordable technique for surface improvement.


Assuntos
Algoritmos , Quitosana , Embalagem de Alimentos , Nanopartículas/química , Quitosana/química , Heurística Computacional , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura
11.
Food Chem ; 337: 127630, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32791432

RESUMO

The current study developed a cheap and effective method for the simultaneous extraction of 14 heterocyclic aromatic amines (HAAs) in food matrix. Core-shell Fe3O4@PDA nanoparticles were constructed and acted as the magnetic solid-phase extraction adsorbent to separate and purify HAAs from meat products for the first time. Then, UPLC-MS/MS technique was employed to identify and quantify the HAAs easily. Fe3O4@PDA nanoparticles were synthesized and characterized successfully. Totally 14 HAAs were completely separated in 19.99 min with good regression coefficients. LODs and LOQs were in the range of 0.013-0.247 ng/g and 0.056-0.803 ng/g, respectively. The intra-day precisions and inter-day precisions were below 9%. Except for IQ[4,5-b], Phe-p-1, PhIP, other 11 types of HAAs (DMIP, 1,5,6-TMIP, IQ, IQx, MeIQ, MeIQx, 7,8-DiMeIQx, AαC, MeAαC, Harman, Norharman) could acquire relatively high recoveries (71.06%-108.49%). The proposed method was successfully devoted to the evaluation of HAAs levels in 8 commercial meat products to verify the adaptability.


Assuntos
Compostos Heterocíclicos/análise , Produtos da Carne/análise , Nanopartículas/química , Extração em Fase Sólida/métodos , Aminas/análise , Aminas/química , Aminas/isolamento & purificação , Animais , Carbolinas/análise , Cromatografia Líquida , Análise de Alimentos/métodos , Compostos Heterocíclicos/isolamento & purificação , Imidazóis/análise , Indóis/química , Fenômenos Magnéticos , Microscopia Eletrônica de Varredura , Polímeros/química , Carne de Porco/análise , Quinolinas/análise , Quinoxalinas/análise , Extração em Fase Sólida/instrumentação , Espectroscopia de Infravermelho com Transformada de Fourier , Espectrometria de Massas em Tandem
12.
Sci Total Environ ; 752: 141937, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33207528

RESUMO

The increased contamination of surface water with plastic waste is proportional to the increased consumption of products that use them as raw material. However, the impact of these residues on aquatic biota remains limited, mainly when it comes to nanoplastics (NPs). Thus, the aim of the current study is to test the hypothesis that the exposure of Ctenopharyngodon idella juveniles to polystyrene nanoplastics (PS NPs) at low concentrations (0.04 ng/L, 34 ng/L and 34 µg/L), for 20 days, leads to DNA damage and has mutagenic and cytotoxic effects on their erythrocytes. Comet assay enabled observing that DNA damage (inferred from the greater tail length, DNA percentage in the tail and Olive tail moment) induced by PS NPs has increased as the pollutant concentrations have increased, as well as that the formation of micronuclei and other nuclear abnormalities was equitable in animals exposed to this pollutant. On the other hand, there were significant changes in erythrocyte shape and size, oxidative stress generation (NO levels, lipid peroxidation, hydrogen peroxide), antioxidant system inhibition (mediated by total hepatic glutathione) and PS NPs accumulation in the liver and brain of animals exposed to higher concentrations of it. Therefore, the current study has confirmed the initial hypothesis and enhanced the knowledge about the genotoxic, mutagenic and cytotoxic potential of PS NPs in freshwater fish at early developmental stage, relating these effects to biochemical changes and significant accumulation of these nanomaterials. Besides, it is a warning about the (eco) toxicological risk represented by these nanopollutants in aquatic environments. CAPSULE: Polystyrene nanoplastics are capable of inducing DNA damage, mutagenic and cytotoxicity changes in fish.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Animais , Dano ao DNA , Microplásticos , Mutagênicos/toxicidade , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade
13.
Chemosphere ; 262: 127784, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32777612

RESUMO

While several studies have investigated the potential impact of nanoplastics, proof of their occurrence in our global environment has not yet been demonstrated. In the present work, by developing an innovative analytical strategy, the presence of nanoplastics in soil was identified for the first time. Our results demonstrate the presence of nanoplastics with a size ranging from 20 to 150 nm and covering three of the most common plastic families: polyethylene, polystyrene and polyvinyl chloride. Given the amount of organic matter in the soil matrix, the discrimination and identification of large nanoplastic aggregates are challenging. However, we provided an innovative methodology to circumvent the organic matter impact on nanoplastic detection by coupling size fractionation to molecular analysis of plastics. While photodegradation has been considered the principal formation pathway of nanoplastics in the environment, this study provides evidence, for the first time, that plastic degradation and nanoplastic production can, however, occur in the soil matrix. Moreover, by providing an innovative and simple extraction/analysis method, this study paves the way to further studies, notably regarding nanoplastic environmental fate and impacts.


Assuntos
Monitoramento Ambiental/métodos , Microplásticos/análise , Nanopartículas/análise , Poluentes do Solo/análise , Solo/química , França , Tamanho da Partícula , Polietileno/análise , Poliestirenos/análise , Cloreto de Polivinila/análise
14.
Chemosphere ; 262: 128330, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182093

RESUMO

Recently, there have been reports that many microplastics are found in the air, which has raised concerns about their toxicity. To date, however, only limited research has investigated the effects of micro(nano)plastics on human health, and even less the potential for inhalation toxicity. To fill this research gap, we investigated the potential inhalation toxicity of micro(nano)plastics using a modified OECD Guideline for Testing of Chemicals No. 412 '28-Day (subacute) inhalation toxicity study' using a whole-body inhalation system. Sprague-Dawley rats were exposed to three different exposure concentrations of polystyrene micro(nano)plastics (PSMPs), as well as control, for 14 days of inhalation exposure. After 14 days, alterations were observed on sevral endpoints in physiological, serum biochemical, hematological, and respiratory function markers measured on the samples exposed to PSMPs. However, no concentration-response relationships were observed, suggesting that these effects may not be definitively linked to exposure of PSMPs. On the other hand, the expression of inflammatory proteins (TGF-ß and TNF-α) increased in the lung tissue in an exposure concentration-dependent manner. The overall results indicate that 14-day inhalation exposure of PSMPs to rats has a more pronounced effect at the molecular level than at the organismal one. These results suggest that if the exposure sustained, alterations at the molecular level may lead to subsequent alterations at the higher levels, and consequently, the health risks of inhalation exposed micro(nano)plastics should not be neglected.


Assuntos
Exposição por Inalação/efeitos adversos , Pulmão/efeitos dos fármacos , Microplásticos/toxicidade , Nanopartículas/toxicidade , Poliestirenos/toxicidade , Aerossóis , Animais , Feminino , Humanos , Pulmão/metabolismo , Pulmão/patologia , Masculino , Microplásticos/farmacocinética , Nanopartículas/metabolismo , Organização para a Cooperação e Desenvolvimento Econômico , Tamanho da Partícula , Poliestirenos/farmacocinética , Ratos , Ratos Sprague-Dawley , Testes de Função Respiratória , Propriedades de Superfície
15.
J Environ Manage ; 277: 111495, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33069150

RESUMO

In this study, we investigated the potentials of nanomaterials to enhance anaerobic ammonium oxidation (anammox) process, in terms of nitrogen removal, microbial enrichment, and activity of key enzymes. Graphene nanosheets (GNs) and γ-Fe2O3 nanoparticles (NPs) were selected due to their catalytic functions as conductive material and electron shuttles, respectively. The obtained results revealed that the optimum dosage of GNs (10 mg/L) boosted the nitrogen removal rate (NRR) by 46 ± 3.1% compared to the control, with maximum NH4+-N and NO2--N removal of 86.5 ± 2.7% and 97.1 ± 0.5%, respectively. Moreover, hydrazine dehydrogenase (HDH) enzyme activity was augmented by 1.1-fold when using 10 mg/L GNs. The presence of GNs promoted the anammox granulation via enhancement of hydrophobic interaction of extracellular polymeric substances (EPS). Regarding the use of γ-Fe2O3 NPs, 100 mg/L dose increased NRR by 55 ± 3.8%; however, no contribution to HDH enzyme activity and a decrease in EPS compositions were observed. Given that the abiotic use of γ-Fe2O3 NPs further resulted in high adsorption efficiency (~92%), we conclude that the observed promotion due to γ-Fe2O3 NPs was mainly abiotic. Moreover, the 16S rRNA analysis revealed that the relative abundance of genus C. Jettenia (anammox related bacteria) increased from 11.9% to 12.3% when using 10 mg/L GNs, while declined to 8.3% at 100 mg/L γ-Fe2O3 NPs. Eventually, nanomaterials could stimulate the efficiency of anammox process, and this promotion and associated mechanism depend on their dose and composition.


Assuntos
Compostos de Amônio , Grafite , Nanopartículas , Anaerobiose , Reatores Biológicos , Nitrogênio , Oxirredução , RNA Ribossômico 16S , Esgotos
16.
Food Chem ; 338: 127769, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32862067

RESUMO

Illegal addition of melamine (MEL) to milk has caused serious food safety accident. It is urgent to develop a highly sensitive method for detecting MEL in milk. ß-Cyclodextrin with inner hydrophobic and outer hydrophilic cavities have been widely used in smart sensors design. In this study, an "ON-OFF-ON" sensor for MEL detection was constructed based on ß-cyclodextrin modified carbon nanoparticles (ß-CD-CNPs). The sensor is switched "OFF" when Fe3+ interacts with ß-CD-CNPs and switched "ON" when MEL replaces Fe3+. Fluorescence recovery of ß-CD-CNPs exhibits good linear correlations with MEL concentration ranging from 10.00 ng/mL ~ 180.00 ng/mL and 180.00 ~ 1000.00 ng/mL, the detection limit is 6.82 ng/mL. The sensor was applied to analysis melamine in milk samples with recovery between 94.80% ~ 102.05%, and RSD bellow 12.61%. The results show that this method can meet the requirements of real sample analysis.


Assuntos
Carbono/química , Análise de Alimentos/métodos , Leite/química , Nanopartículas/química , Triazinas/análise , Triazinas/química , beta-Ciclodextrinas/química , Animais , Contaminação de Alimentos/análise , Limite de Detecção , Espectrometria de Fluorescência
17.
Food Chem ; 335: 127609, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32739808

RESUMO

In this study, a fluorescence resonance energy transfer (FRET) immunoassay based on graphene oxide (GO) and up-converting nanoparticles (UCNPs) was established for rapid detection of imidacloprid, a commonly-used insecticide. Under 980 nm near-infrared light excitation, emission of UCNPs at 542 nm can be absorbed by the energy acceptor GO. The carboxyl-functionalized GO and UCNPs were coupled with competitive antigen and antibody against imidacloprid. After optimization, the FRET immunoassay showed a wide detection range of 0.08-50 ng/mL to imidacloprid, with cross-reaction toward other three neonicotinoids including imidaclothiz (74.4%), thiacloprid (36.9%) and clothianidin (31.9%). The average recoveries of spiked water, Chinese cabbage, cucumber, honey and tea samples were 76.8%-101.8%. The accuracy and reliability of the FRET immunoassay were verified by UPLC-MS/MS with a good correlation (R2 = 0.9816). In a summary, this study provides a sensitive and one-step method for monitoring imidacloprid residue in food and environmental samples within 1 h.


Assuntos
Grafite/química , Nanopartículas/química , Neonicotinoides/análise , Nitrocompostos/análise , Cromatografia Líquida , Transferência Ressonante de Energia de Fluorescência/métodos , Imunoensaio/métodos , Limite de Detecção , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem , Tiazóis
18.
J Environ Manage ; 277: 111415, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33010657

RESUMO

Remote areas and poor communities are occasionally deprived of access to freshwater. It is, therefore, critical to providing a cheap and efficient desalination system that encourages the development of those communities and benefiting society at large. Solar stills are an affordable, direct method of water desalination, but its productivity is the critical challenge hindering its application. To ease this, research has focused on the role of nanofluids to improve heat transfer. Other works have focused on improving the design in consort with utilizing the nanofluids. This review reports and discusses the substantial role of nanofluids to enhance the productivity and energy utilization efficiency of the solar stills. Specifically, the mechanism of energy transfer between the nanoparticles and the base fluid. This includes both plasmonic and thermal effects. It is evident that nanofluid utilization in small fraction enhanced the thermal conductivity compared to base fluid alone. Alumina was found to be the most suitable nanoparticle used as nanofluid inside the solar stills due to its availability and lower cost. Still, other competitors such as carbon nanostructures need to be investigated as it provides higher enhancement of thermal conductivity. Also, several aspects of energy utilization enhancement have been discussed, including innovative application techniques. The challenges of such integrated systems are addressed as well.


Assuntos
Nanopartículas , Energia Solar , Temperatura Alta , Luz Solar , Condutividade Térmica
19.
J Environ Manage ; 277: 111428, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33035936

RESUMO

Titanium dioxide nanoparticles (TiO2 NPs) are widely used in consumer products and one of their major fate is the wastewater treatment plants. However, NPs eventually arrive to aquatic and terrestrial ecosystems via treated water and biosolids, respectively. Since low concentration of NPs is accumulating in the upflow anaerobic sludge blanket (UASB) reactors that treat wastewater and reclaim water quality, the accumulation of TiO2 NPs in these reactors may impact in their performance. In this work, the long-term effects of TiO2 NPs on the main benefits of treating wastewater by UASB reactors such as, biogas production, methane fraction in biogas and organic matter removal were evaluated. Evaluation consisted of monitoring such parameters in two identical UASB reactors, one UASB-Control (without NPs) and the experimental one (UASB-TiO2 NPs) that received wastewater with TiO2 NPs. The fate of NPs in the UASB reactor was also determined. Results indicated that biogas production increased by 8.8% due to the chronic exposure of UASB reactor to TiO2 NPs during the first 44 days of experiment. However, the methane content in the biogas had no significant differences between both UASB, ranging between 78% and 90% of methane during the experiment. The removal of organic matter in both UASB was similar and ranged 92-98% along the experimental time. This means that accumulation of TiO2 NPs did not altered the biogas production and organic matter removal. However, the content of total volatile solids (TVS) in UASB-TiO2 NPs dropped off from 137.8 g to 64.2 g in 84 days, while for control reactor that decreased from 141.6 g to 92.4 g in the same period. Hence, the increased biogas production in the UASB exposed to TiO2 was attributed to hydrolysis of the TVS in this reactor. The main fate of TiO2 NPs was the granular sludge, which accumulated up to 8.56 mg Ti/g, which represent around 99% of the Ti spiked to the reactor and the possible cause of the biomass hydrolyzation in the UASB. Disposal of UASB sludge containing NPs from may raise ecotoxicological concerns due to the use of biosolids in agricultural activities.


Assuntos
Nanopartículas , Águas Residuárias , Anaerobiose , Reatores Biológicos , Ecossistema , Metano , Esgotos , Titânio , Eliminação de Resíduos Líquidos
20.
Chemosphere ; 262: 127805, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32750593

RESUMO

The present study assessed the individual and combined toxicity effects of Ag- and TiO2- nanoparticles (NPs) on Ag bioaccumulation, oxidative stress, and gill histopathology in common carp as an aquatic animal model. The 96-h acute toxicity tests showed that TiO2NPs enhanced the toxicity of AgNPs deducted from the decreased LC50 in co-exposure to these NPs. Chronic toxicity tests included a 10-day exposure and a 10-day recovery period. In most cases, histological damages were more severe in co-exposure to Ag- and TiO2- NPs compared with the individual AgNPs however, they were reduced in some cases and also after the recovery period. In co-exposure to Ag- and TiO2- NPs, the Ag bioaccumulation was decreased in the gills but increased in the liver and intestine compared with the singular exposure. After the recovery period, Ag bioaccumulation decreased especially in the liver. Decreased levels of antioxidant enzymes were observed in the AgNPs exposed groups, which were partially alleviated by TiO2NPs. The reduction of condition factor (CF) and hepatosomatic index (HSI) and a severe decrease of weight gain (WG) were observed in co-exposure to Ag- and TiO2- NPs. After the recovery period, the CF and HSI increased but the WG decreased less compared with the exposure period. The present results emphasize the importance of considering the co-existence and interaction of NPs in realizing their bioavailability and toxicity in aquatic environments.


Assuntos
Carpas/fisiologia , Nanopartículas Metálicas/toxicidade , Titânio/química , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Brânquias , Dose Letal Mediana , Fígado/metabolismo , Nanopartículas/toxicidade , Estresse Oxidativo , Prata/toxicidade
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