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1.
RSC Adv ; 12(33): 21026-21040, 2022 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-35919837

RESUMO

Magnetic graphene oxide (MGO) was prepared and used as a catalyst to activate peroxymonosulfate (PMS) for degradation of Coomassie brilliant blue G250 (CBB). The effects of operation conditions including MGO dosage, PMS dosage and initial concentration of CBB were studied. CBB removal could reach 99.5% under optimum conditions, and high removals of 98.4-99.9% were also achieved for other organic dyes with varied structures, verifying the high efficiency and wide applicability of the MGO/PMS catalytic system. The effects of environmental factors including solution pH, inorganic ions and water matrices were also investigated. Reusability test showed that CBB removals maintained above 90% in five consecutive runs, indicating the acceptable recyclability of MGO. Based on quenching experiments, solvent exchange (H2O to D2O) and in situ open circuit potential (OCP) test, it was found that ˙OH, SO4˙- and high-valent iron species were responsible for the efficient degradation of CBB in the MGO/PMS system, while the contributions of O2˙-, 1O2 and the non-radical electron-transfer pathway were limited. Furthermore, the plausible degradation pathway of CBB was proposed based on density functional theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS) results, and toxicity variation in the degradation process was evaluated by computerized structure-activity relationships (SARs) using green algae, daphnia, and fish as indicator species.

2.
Chemosphere ; : 135628, 2022 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-35810871

RESUMO

In this study, a Ti3+-doped TiO2 porous membrane (Blue TiO2/Ti) was fabricated and employed for electrochemical degradation of organic pollutants in the single-pass flow-through mode. Characterizations including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microcopy (SEM) and energy dispersive spectroscopy (EDS) verified that Ti3+-doped anatase TiO2 with nanotube structures was successfully prepared. Electrochemical analysis including linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and electrochemical active surface area (ESA) revealed higher oxygen evolution potential (OEP, 2.23 V vs. Ag/AgCl), larger redox peak current, lower impedance and larger ESA (69 cm2/cm2) of Blue TiO2/Ti compared to the Ti and TiO2/Ti membrane. The effects of current density, flow rate and solution environment on the removal of methylene blue (MB) were investigated. The removal rate of various organic pollutants including sulfamethoxazole (SMX), methyl orange (MO), bisphenol A (BPA) and MB could reach 92.2%-99.5%. The quenching experiment proved that hydroxyl radicals (•OH) played the major role in the Blue TiO2/Ti based electrochemical system. Furthermore, the degradation pathways of two typical pollutants (SMX and MB) were proposed by analyzing the oxidation products with liquid chromatography-mass (LC-MS) and gas chromatography-mass spectrometry (GC-MS), with the assistance of orbital-weighted Fukui index (fw0 and fw-) obtained through Density Functional Theory (DFT) calculations. Moreover, toxicity indexes of the oxidation products were obtained and compared to the parent SMX and MB using Toxicity Estimation Software Tool (TEST) software. Finally, the long-term operation performance of the Blue TiO2/Ti membrane was evaluated.

3.
Sci Total Environ ; 827: 154274, 2022 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-35247411

RESUMO

Emerging per-and polyfluoroalkyl substances (PFASs) and traditional organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) in the marginal seas of China were analyzed to study the occurrence, transport and phase partitioning. The influence of organic carbon (OC) and element carbon (EC) on particulate emerging pollutants in seawater was studied for the first time. The concentrations of PFASs, OCPs and PAHs in the seawater (dissolved phase plus particulate phase) ranged from 1.4 to 8.6, 0.76 to 4.3 and 8.4 to 130 ng L-1, respectively. Pollutants in the northern East China Sea were generally higher than that in the southern East China Sea and South China Sea, which may be attribute to river discharges and land sources in the Yangtze River Delta. The Yellow Sea Coastal Current and Yangtze River Dilute Water drove the transport of contaminants from north to south marginal seas. Positive correlations between EC and PAHs were found, which can be explained by co-emission of them during combustion. Moreover, positive correlations between OC, EC and Log Kd for BkF, BeP, HCB, 6:2 FTSA were found, which demonstrated that OC and EC promoted the partitioning of these high oleophilic compounds to suspended particle.


Assuntos
Fluorcarbonetos , Hidrocarbonetos Clorados , Praguicidas , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Carbono/análise , China , Carvão Mineral , Monitoramento Ambiental , Hidrocarbonetos Clorados/análise , Oceanos e Mares , Poluentes Orgânicos Persistentes , Praguicidas/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Rios , Poluentes Químicos da Água/análise
4.
Environ Sci Pollut Res Int ; 29(20): 30774-30789, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34993777

RESUMO

A series of Fe3O4-graphene oxide (GO) composite materials (MGOs) with abundant surface area, rich oxygen-containing functional groups, and magnetic properties were prepared in a facile coprecipitation method and then employed for the adsorptive removal of methylene blue (MB) from water. The kinetic data were better fitted in the pseudo-second-order model than in the pseudo-first-order model, and the intraparticle diffusion model revealed the two-step diffusion process including diffusion in the boundary layer and in the porous structures. The maximum adsorption amounts of MB were calculated to be 37.5-108 mg/g at 25 °C and pH 9 using the Langmuir isotherm model. Thermodynamic study showed that the adsorption process was spontaneous, with ΔH° of 23.0-49.6 kJ/mol and ΔS° of 131-249 J∙mol-1∙K-1. The adsorption amount of MB increased with pH in the range of 4-10. Inorganic ions including Na+ and Ca2+ suppressed the adsorption of MB, and the more pronounced impact of Ca2+ was ascribed to its higher valence state. The cetyltrimethylammonium bromide (CTAB) surfactant showed a stronger inhibitory effect than Ca2+. The adsorption mechanism was proposed to be a combination of electrostatic interactions, hydrophobic adsorption, and electron donor-acceptor interactions. Two methods were used for the regeneration of spent MGO, and the results showed that the peroxomonosulfate (PMS) oxidation method was more favorable than the acid washing method, considering the better regeneration ability and lower amount of washing water used. Finally, the reaction mechanism of PMS oxidation was analyzed based on quenching tests and in situ open circuit potential measurements, which proved that OH and 1O2 played dominant roles and that the fine adsorption ability of MGO promoted the reaction between them and MB.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Adsorção , Grafite , Concentração de Íons de Hidrogênio , Íons , Cinética , Óxido de Magnésio , Fenômenos Magnéticos , Azul de Metileno/química , Água , Poluentes Químicos da Água/análise , Purificação da Água/métodos
6.
J Colloid Interface Sci ; 607(Pt 1): 451-461, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34509119

RESUMO

In this study, a functionalized Co3O4-Bi2O3-Ti catalytic membrane (CBO-Ti-M) was prepared and applied for removing organic pollutants via activating peroxymonosulfate (PMS) in the dead-end filtration mode. Characterizations including scanning electron microcopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) showed that the Co3O4-Bi2O3 catalyst was successfully supported on the Ti membrane. The CBO-Ti-M /PMS system could efficiently remove various organic pollutants such as sulfamethoxazole, methyl orange, bisphenol A and methylene blue, achieving removal efficiencies of 98.0%-99.5%. The effects of PMS concentration, flow rate and solution environment on degradation efficiency were investigated in detail. Furthermore, quenching experiments, electron spin resonance (ESR) and in-situ open circuit potential (OCP) tests collectively demonstrated that singlet oxygen as well as the non-radical electron transfer pathway mainly contributed in the reaction mechanism. The synergistic effect of Co and Bi was illustrated according to XPS results, and the possible degradation pathway of MB was proposed based on LC-MS analysis. Reusability test showed that pollutant removal efficiency with the CBO-Ti-M /PMS system remained stable in four runs and limited metal leaching was observed.


Assuntos
Poluentes Ambientais , Água , Peróxidos , Titânio
7.
Environ Sci Pollut Res Int ; 28(30): 41268-41282, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33779907

RESUMO

In the present study, five magnetic multi-walled carbon nanotubes (MMWCNTs) with different diameters were prepared and their performance on the sorptive removal of methylene blue (MB) from water was investigated. Transmission electron microscope, scanning electron microscope, Fourier transform infrared spectrometer, X-ray diffraction, and vibrating sample magnetometer confirm that the surface of these MMWCNTs has been decorated by Fe3O4 nanoparticles, which renders the MMWCNTs superparamagnetic. Thus, these MMWCNTs can be easily separated from water after the adsorption. During the adsorption process, pH slightly affected the removal efficiency of MB and the adsorption performed better under weak alkaline conditions. Adsorption kinetics followed the pseudo-second-order kinetic model well, and the Dubinin-Radushkevich model fitted the isotherms best. The maximum adsorption capacity for MB reached 204.2 mg/g, and the values decreased with increasing diameters of MMWCNTs due to decreasing specific surface areas. The thermodynamics parameters indicated the spontaneous and exothermic nature of the adsorption. The reusability test showed that MMWCNTs could be used for 6 cycles without significant loss of the adsorption capacity. And common ions (K+, Na+, Ca2+ and Al3+) and SDS in water did not show greatly effects on the removal efficiency of MB. Hence, MMWCNTs prepared in this study could be promising adsorbents for dyes removal from wastewater.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Purificação da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Magnéticos , Azul de Metileno , Termodinâmica , Água , Poluentes Químicos da Água/análise
8.
HPB (Oxford) ; 23(7): 1061-1071, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33309570

RESUMO

BACKGROUND: Tumor microenvironment plays an essential role during the progression of hepatocellular carcinoma (HCC). Tumor infiltrating immune cells (TILs) was an important component of tumor microenvironment. However, whether TIL features are correlated with the prognosis of HCC patients remains unclear. METHODS: Cancer tissue and paired paracancerous tissues from 220 stage II∼III HBV-related HCC patients were collected. TILs were analyzed using a tyramide signal amplification system combined with immunohistochemistry. Kaplan-Meier survival analysis was conducted to investigate the associations between the prognosis and the infiltrating pattern of TILs. RESULTS: The patients were classified into three distinct subgroups (Clusters (C)1-3) with different overall survival (OS) and disease-free survival (DFS) according to the distribution pattern of TILs. The CD68/CD8 ratio in the cancer SA was correlated with the prognosis. Patients with a higher CD68/CD8 ratio exhibited poorer OS and DFS than those with a lower ratio. The CD68/CD8 ratio in the cancer SA was an independent factor for OS prediction but not DFS. CONCLUSION: CD68+ macrophages and CD8+ T-cells are essential immunological determinants for HBV-related HCC prognosis, and the CD68/CD8 ratio in cancer SA is a novel, prognostic factor for OS prediction in HBV-related HCC patients.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Linfócitos T CD8-Positivos , Carcinoma Hepatocelular/terapia , Vírus da Hepatite B/genética , Humanos , Neoplasias Hepáticas/terapia , Linfócitos do Interstício Tumoral , Macrófagos , Prognóstico , Microambiente Tumoral
9.
Sci Total Environ ; 763: 143053, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33129528

RESUMO

To further understand the underlying mechanisms involved in the developmental toxicity of crude oil and chemically dispersed crude oil on fish early-life stages (ELS), zebrafish (Danio rerio) embryos were exposed to GM-2 chemical dispersant (DISP), low-energy water-accommodated fractions (LEWAF), and chemically enhanced WAF (CEWAF) of Merey crude oil at sublethal concentrations for 120 h. We employed the General Morphology Score (GMS) and General Teratogenic Score (GTS) systems in conjunction with high-throughput RNA-Seq analysis to evaluate the phenotypic and transcriptomic responses in zebrafish ELS. Results showed that ΣPAHs concentrations in LEWAF and CEWAF solutions were 507.63 ± 80.95 ng·L-1 and 4039.51 ± 241.26 ng·L-1, respectively. The GMS and GTS values indicated that CEWAF exposure caused more severe developmental delay and higher frequencies of teratogenic effects than LEWAF exposure. Moreover, no significant change in heart rate was observed in LEWAF treatment, while CEWAF exposure caused a significant reduction in heart rate. LEWAF and CEWAF exposure exhibited an overt change in eye area, with a reduction of 4.0% and 25.3% (relative to the control), respectively. Additionally, no obvious impact on phenotypic development was observed in zebrafish embryo-larvae following DISP exposure. Significant changes in gene expression were detected in LEWAF and CEWAF treatments, with a total of 957 and 2062 differentially expressed genes (DEGs), respectively, while DISP exposure altered only 91 DEGs. Functional enrichment analysis revealed that LEWAF and CEWAF exposure caused significant perturbations in the pathways associated with phototransduction, retinol metabolism, metabolism of xenobiotics by cytochrome P450, and immune response-related pathways. Our results provide more valid evidence to corroborate the previous suggestion that ocular impairment is an equal or possibly more sensitive biomarker than cardiotoxicity in fish ELS exposed to oil-derived PAHs. All these findings could gain further mechanistic insights into the effects of crude oil and chemical dispersant on fish ELS.


Assuntos
Poluição por Petróleo , Petróleo , Poluentes Químicos da Água , Animais , Petróleo/toxicidade , Poluição por Petróleo/efeitos adversos , Transcriptoma , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
10.
Cancer Med ; 9(14): 5075-5085, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32458568

RESUMO

PURPOSE: To characterize plasma cell-free cancer genome chromosomal instabilities (CIN) in patients with liver cancer and to evaluate the potential of CIN as minimally invasive biomarkers for primary liver cancer (PLC) diagnoses. EXPERIMENTAL DESIGN: We collected 196 plasma samples from 172 individuals in two cohorts, a discovery cohort of surgery ineligible PLC patients and a validation cohort of hepatectomy patients with pathological disease confirmations. All samples were subjected to HiSeq X10 sequencing followed by a customized bioinformatics workflow Ultrasensitive Chromosome Aneuploidy Detection (UCAD). RESULTS: In the discovery cohort, 29 significant copy number changes were identified in plasma from surgery-ineligible PLC. Twenty-two (95.7%) surgery-ineligible liver cancers were identified as harboring copy number changes in at least 1 of 29 segments. Meanwhile 40/41 (97.6%) noncancers harbored no changes. In the validation cohort, 54 (69.4%) surgery-eligible liver cancers were identified with positive screening, all of which were subsequently confirmed as cancer by pathological examination. Moreover, 26/27 = 96.3% noncancers were identified with negative screening. UCAD-positive screening was significantly associated with microvascular invasion (OR > 10, 95% CI:[2.53,]), tumor stages B and C (OR = 8.59, 95% CI [1.07, 400]), and tumor size ≥ 3 cm (OR = 5.68, 95% CI [1.43, 28.1]). Furthermore, we collected 29 followed-up plasma samples from 19 postsurgery patients. Nine (31.0%) postsurgery samples from 6 (31.5%) patients were identified with positive screening. Among them, 3 patients (50.0%) with positive screening were then confirmed as having disease recurrences. CONCLUSIONS: In addition to AFP, plasma cell-free DNA sequencing is a useful tool for primary liver cancer diagnoses.


Assuntos
Biomarcadores Tumorais/metabolismo , Instabilidade Cromossômica/genética , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Neoplasias Hepáticas/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
11.
Ecotoxicol Environ Saf ; 193: 110332, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32088550

RESUMO

Aggregation of C60, as an important process governing its mobility and toxicity, has been quantitatively investigated. However, effects of sunlight and agitation intensity on the aggregation behavior of aqu/nC60 produced via extended mixing, have not been clarified. Therefore, in the present study, the aggregation behavior of aqu/nC60 produced at 500 and 800 rpm in the absence and presence of sunlight was investigated. Aggregation with increasing concentrations could be accelerated, while changes of Zave and zeta potential were not obvious. Critical coagulation concentrations (CCCs) of aqu/nC60 obtained at 800 rpm in the absence/presence of sunlight and that at 500 rpm under sunlight were 330, 205 and 170 mM NaCl, and 10.0, 2.6 and 3.1 mM CaCl2, respectively. These CCCs indicated that the aqu/nC60 prepared by the extended mixing were more stable than those produced by other methods. Salt-induced aggregation occurred more easily for aqu/nC60 formed under sunlight than that formed in the dark. Extra surface oxidation induced by high agitation intensity remarkably increased the stability of aqu/nC60 in NaCl solutions. In contrast, in CaCl2 solutions, aqu/nC60 formed at high agitation intensity had similar stability or even inadequate stability to that obtained at low agitation intensity due to the charge neutralization and cross-link bridging.


Assuntos
Fulerenos/química , Nanopartículas/química , Luz Solar , Fulerenos/efeitos da radiação , Nanopartículas/efeitos da radiação , Cloreto de Sódio/química
12.
Environ Sci Pollut Res Int ; 27(11): 12527-12538, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32002835

RESUMO

Once released into natural water, the environmental behavior and fate of C60 could inevitably been affected by humic acid (HA), sunlight, and hydrodynamic conditions. However, the combined effects of these factors are not so clear. Therefore, in the present study, effects of HA, sunlight, and agitation intensity on generation and properties of aqu/nC60 were investigated. The results indicated that HA could increase the concentration of aqu/nC60 mainly through the steric hindrance effect. The higher agitation intensity led to higher concentrations of aqu/nC60 and more efficient steric stabilization was formed by HA. Sunlight irradiation promoted the surface oxidization and consequently enhanced the dispersion of C60. The relative order of the influence on the UV/vis concentration was sunlight > agitation intensity > HA. In addition, HA might not always enhance the dispersion of aqu/nC60 due to light screening/ROS scavenging, over-coating, or chain-like bridging mechanism. Therefore, evaluating the environmental behavior and fate of C60 should take these factors into account together.


Assuntos
Fulerenos , Poluentes Químicos da Água , Substâncias Húmicas/análise , Luz Solar , Água
13.
Chemosphere ; 242: 125246, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31704525

RESUMO

Temperature-dependent octanol-air partition coefficients (KOA) are of great importance in assessing the environmental behavior and fate of persistent organic pollutants including polychlorinated biphenyls (PCBs). Due to the tremendous amounts of time, effort and cost needed for the experimental determination of KOA, it is desirable to develop a rapid and precise predictive method to estimate KOA just based on molecular structure. In the present study, a predictive model for log KOA of PCBs at ambient temperatures was developed based on the thermodynamic relationship between KOA and the solvation free energy from air to octanol (ΔGOA). For the calculation of ΔGOA of PCBs, the optimal combination of theoretical method and basis-set was identified to be HF/MIDI!6D for both geometry optimization and energy calculation. Dimer formation could affect the partition behavior and promote the apparent KOA values of PCBs. After taking the effect of dimer formation into account, the goodness-of-fit, predictive ability, and robustness of the predictive model were significantly improved. Apparent log KOA values of PCBs at different ambient temperatures ranging from 283.15 to 303.15 K were predicted. Compared with other reported models, the model developed in the present study had not only comparable goodness-of-fit and predictive ability, but also a universal application domain and the relative independency of experimental data. Therefore, the solvation free energy method could be a promising method for the prediction of KOA.


Assuntos
Modelos Químicos , Bifenilos Policlorados/química , Temperatura , Termodinâmica , Poluentes Ambientais/análise , Octanóis/química , Bifenilos Policlorados/análise , Solventes/química
14.
Chemosphere ; 235: 423-433, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31272002

RESUMO

The present study investigated the developmental toxicity of water-accommodated fractions (WAFs) of Oman crude oil (OCO) and Merey crude oil (MCO) on zebrafish (Danio rerio) in early-life stages (ELS). Based on total petroleum hydrocarbons (TPH), LC50 values manifested that OCO WAF was 1.2-fold more lethal to zebrafish embryos than MCO WAF. As for hatching rate, EC50 value for OCO WAF was 5.7-fold lower than that for MCO WAF. To evaluate the sublethal morphological effects, semi-quantitative extended general morphological score (GMS) and general teratogenic score (GTS) systems were adopted. The GMS and GTS scores indicated that the WAFs caused remarkable developmental delay and high frequencies of malformation in a dose-dependent manner. Additionally, OCO and MCO WAFs exposure exhibited severe bradycardia (reduced heart rate) and overt reduction of stroke volume, with a concomitant decrease in the cardiac output. Meanwhile, the WAFs also induced dose-dependent down-regulated expressions of several key functional genes of excitation-contraction coupling in cardiomyocytes, including ryr2, atp2a2a, atp2a2b, ncx1h, and kcnh2. For key gene markers of swim bladder development, results showed that high dose of TPH induced significant down-regulation of hb9 and anxa5 with no obvious change of acta2, suggesting that the WAFs could affect the specification and development of epithelium and outer mesothelium of swim bladder in zebrafish ELS. A strong negative relationship between the failure of swim bladder inflation and cardiac dysfunction via cardiac output was found. All these findings provide novel insights into the complicated mechanisms of the developmental toxicity of crude oil on fish in ELS.


Assuntos
Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , Animais , Omã , Organogênese , Poluição por Petróleo , Bexiga Urinária/efeitos dos fármacos , Bexiga Urinária/crescimento & desenvolvimento , Água , Poluentes Químicos da Água/análise , Peixe-Zebra/crescimento & desenvolvimento
15.
Environ Sci Pollut Res Int ; 26(25): 25538-25549, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267391

RESUMO

Environmental waters cover a range of water quality characteristics which could greatly affect the behavior and fate of C60 in the aquatic environment. In this study, the dispersion and stability of C60 in several environmental water matrices during a 70-day extended mixing period were investigated to better understand its environmental behavior and fate in environmental waters. Relatively stable nanoscale aggregates in water (aqu/nC60) could be formed in wastewater influent, while unstable suspensions were obtained in river water, wastewater effluent, seawater, and estuarine water. During the extended mixing under sunlight, oxygen-containing moieties were produced on the surface of the C60 aggregates, independent of the kind of environmental water matrices. Once the mixed system went under quiescent condition, aggregation and sedimentation of aqu/nC60 occurred. However, an extremely short-time disturbance could easily resuspend the C60 aggregates deposited and increase the concentration of aqu/nC60 in the overlying water column. Therefore, the effects of resuspension should be considered when investigating the environmental behavior and fate of C60.


Assuntos
Águas Residuárias/análise , Fulerenos/química , Luz Solar , Suspensões/química
16.
Chemosphere ; 234: 123-131, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31207418

RESUMO

Microplastics are a ubiquitous contaminant of marine ecosystems that have received considerable global attention. The effects of microplastic ingestion on some marine biota have been evaluated, but the uptake, elimination, and histopathological impacts of microplastics remain under-investigated especially for zooplankton larvae. Here, we show that 10 µm polystyrene microspheres can be ingested and egested by Artemia parthenogenetica larvae, which impact their health. The results indicate that A. parthenogenetica larvae have a varying capacity to consume 10 µm polystyrene microspheres that is dependent on microplastic exposure concentrations, exposure times, and the availability of food. The lowest level of microplastics that was ingested by A. parthenogenetica was 0.15 particles/individual when exposed to 10 particles/mL and 0.05 particles/individual when exposed to 1 particle/mL over 24 h and 14 d, respectively. A. parthenogenetica larvae were able to egest feces with microplastics within 3 h of ingestion. However, ingested microplastics persisted in individuals for up to 14 days. Furthermore, microalgal feeding was significantly reduced by 27.2% in the presence of 102 particles/mL microplastics over 24 h. Histological analyses indicated that a greater abundance of lipid droplets was present among epithelia after 24 h of exposure at a concentration of 10 particles/mL. Moreover, intestinal epithelia were deformed and disorderedly arranged after 14 d of exposure. Overall, these results indicate that marine microplastic pollution could pose a threat to A. parthenogenetica health, especially that of larvae. Consequently, further research is required to evaluate the potential physiological and histopathological effects of microplastics for other marine invertebrate species.


Assuntos
Artemia/metabolismo , Comportamento Alimentar/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Plásticos/farmacocinética , Poliestirenos/farmacocinética , Animais , Artemia/efeitos dos fármacos , Ingestão de Alimentos , Ecossistema , Mucosa Intestinal/patologia , Larva/efeitos dos fármacos , Plásticos/análise , Poliestirenos/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/farmacocinética , Zooplâncton/efeitos dos fármacos
17.
Environ Pollut ; 244: 715-722, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30384077

RESUMO

Microplastics are a contaminant of emerging concern which enter the marine environment from a variety of sources. The ingestion and toxic effects of microplastics on marine life, especially for filter feeders, are a cause of concern in view of their ubiquitous nature and their similar size as food sources. To assess the toxic effects of microspheres ingested by brine shrimp larvae, we exposed Artemia parthenogenetica to 10 µm polystyrene microspheres at different concentrations. These concentrations were approximate to the extrapolated marine aquatic environmentally relevant concentrations. The lowest polystyrene concentrations at which ingestion was visualized in A. parthenogenetica were 12 ±â€¯0.57 particles/mL (6.7 ±â€¯0.32 µg/L) and 1.1 ±â€¯0.16 particles/mL (0.61 ±â€¯0.088 µg/L), respectively. There were no significant impacts on the survival, growth or development in A. parthenogenetica occurring over the 14-d exposure across a range of polystyrene nominal concentrations (1-1000 particles/mL or 0.55-550 µg/L). However, abnormal ultrastructures of intestinal epithelial cells were observed upon exposure to polystyrene microspheres, including fewer and disordered microvilli, an increased number of mitochondrion and the appearance of autophagosome. These phenomena could affect nutrition absorption and energy metabolism. Although no major acute or chronic toxicity effects on A. parthenogenetica were observed over 24-h or 14-d exposures, this study provides evidence that the ingestion of polystyrene microplastics at extrapolated environmentally relevant concentrations can be visualized through a microscope to be causing a series of responses in intestinal epithelial cells.


Assuntos
Artemia/efeitos dos fármacos , Células Epiteliais/patologia , Mucosa Intestinal/patologia , Larva/efeitos dos fármacos , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Artemia/metabolismo , Ingestão de Alimentos , Microesferas , Poliestirenos/análise , Poluentes Químicos da Água/análise
18.
Mar Environ Res ; 141: 138-147, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30177415

RESUMO

Stranding of oil onto a coastline after an oil spill threatens the health of marine benthic organisms. Here, the transgenerational effects of exposure to stranded heavy fuel oil (HFO) on the sea urchin Strongylocentrotus intermedius were assessed. The column containing gravel coated with HFO was prepared in the laboratory to simulate HFO-contaminated gravel shorelines. Adult sea urchins were exposed for 21 days to either a HFO-oiled gravel column at the oil loading of 3000 µg oil/g gravel or a non-HFO-oiled gravel column (as the control treatment) and then offspring were either exposed to HFO or ambient seawater conditions. The sublethal exposure to HFO for 21 days induced polycyclic aromatic hydrocarbons (PAHs) accumulation in gonads, accompanied by increased levels of oxidative lipid, protein and DNA damage and a reduction in total antioxidant capacity. Analysis of gametes indicated that both maternal and paternal exposure could result in the transfer of PAHs and DNA damage to their offspring. Parental (maternal, paternal or both) exposure to HFO caused increases in malformation rates of offspring compared to those from control parents under ambient seawater condition. Continued HFO exposure in the offspring resulted in further increased malformation rates compared with those reared in ambient seawater, as well as oxidative lipid, protein and DNA damage. Furthermore, mother exposure history reduced the total antioxidant capacity of larvae to response to continued HFO exposure. Overall, the results suggest an increased sensitivity to toxic effects of HFO in larvae from exposed both parents compared with those from control parents in S. intermedius, which may consequently affect the recruitment and population maintenance.


Assuntos
Poluentes Ambientais , Óleos Combustíveis , Estresse Oxidativo , Hidrocarbonetos Policíclicos Aromáticos , Strongylocentrotus , Poluentes Químicos da Água , Animais , Biomarcadores , Poluentes Ambientais/farmacocinética , Masculino , Hidrocarbonetos Policíclicos Aromáticos/farmacocinética , Strongylocentrotus/genética
19.
Bull Environ Contam Toxicol ; 101(3): 314-319, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30105540

RESUMO

This study focused on comparing the lethal and sublethal toxicity of water-accommodated fractions (WAF) and chemically enhanced WAF (CEWAF) of crude oil to zebrafish (Danio rerio) on early life stages (ELS). Results showed that the addition of GM-2 dispersant caused an increase in the levels of total petroleum hydrocarbons (TPHs) and total priority polycyclic aromatic hydrocarbons (ΣPAHs). Based on ΣPAHs, the LC20 estimates for WAF and CEWAF were 4.88 µg L-1 and 1.19 µg L-1, respectively, indicating that CEWAF was approximately four times more toxic. CEWAF exposure caused markedly lower hatching rates and higher malformation frequencies than WAF. Meanwhile, the general morphology score (GMS) values in CEWAF were about fourfold lower than that in WAF, indicating that CEWAF exposure induced more significant developmental delay. The results suggested that chemical dispersant enhanced the toxicity of crude oil to zebrafish on ELS and its application could increase the exposure of fishes to crude oil.


Assuntos
Petróleo/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra , Animais , Omã
20.
Sensors (Basel) ; 18(8)2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30111724

RESUMO

A micro-floating element wall shear stress sensor with backside connections has been developed for accurate measurements of wall shear stress under the turbulent boundary layer. The micro-sensor was designed and fabricated on a 10.16 cm SOI (Silicon on Insulator) wafer by MEMS (Micro-Electro-Mechanical System) processing technology. Then, it was calibrated by a wind tunnel setup over a range of 0 Pa to 65 Pa. The measurements of wall shear stress on a smooth plate were carried out in a 0.6 m × 0.6 m transonic wind tunnel. Flow speed ranges from 0.4 Ma to 0.8 Ma, with a corresponding Reynold number of 1.05 × 106~1.55 × 106 at the micro-sensor location. Wall shear stress measured by the micro-sensor has a range of about 34 Pa to 93 Pa, which is consistent with theoretical values. For comparisons, a Preston tube was also used to measure wall shear stress at the same time. The results show that wall shear stress obtained by three methods (the micro-sensor, a Preston tube, and theoretical results) are well agreed with each other.

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