خيارات البحث
النتائج 281 - 290 من 6,560
Visible-light reduced silver nanoparticles’ toxicity in Allium cepa test system النص الكامل
2020
Souza, Irisdoris R. | Silva, Lucas R. | Fernandes, Letícia S.P. | Salgado, Lilian D. | Silva de Assis, Helena C. | Firak, Daniele S. | Bach, Larissa | Santos-Filho, Ronaldo | Voigt, Carmen L. | Barros, Ariana C. | Peralta-Zamora, Patricio | Mattoso, Ney | Franco, Celia Regina C. | Soares Medeiros, Lia C. | Marcon, Bruna H. | Cestari, Marta M. | Sant’Anna-Santos, Bruno F. | Leme, Daniela M.
Silver nanoparticles (AgNPs) are widely used in consumer products due to their antibacterial property; however, their potential toxicity and release into the environment raises concern. Based on the limited understanding of AgNPs aggregation behavior, this study aimed to investigate the toxicity of uncoated (uc-AgNP) and coated with polyvinylpyrrolidone (PVP-AgNP), at low concentrations (0.5–100 ng/mL), under dark and visible-light exposure, using a plant test system. We exposed Allium cepa seeds to both types of AgNPs for 4–5 days to evaluate several toxicity endpoints. AgNPs did not cause acute toxicity (i.e., inhibition of seed germination and root development), but caused genotoxicity and biochemical alterations in oxidative stress parameters (lipid peroxidation) and activities of antioxidant enzymes (superoxide dismutase and catalase) in light and dark conditions. However, the light exposure decreased the rate of chromosomal aberration and micronuclei up to 5.60x in uc-AgNP and 2.01x in PVP-AgNP, and 2.69x in uc-AgNP and 3.70x in PVP-AgNP, respectively. Thus, light exposure reduced the overall genotoxicity of these AgNPs. In addition, mitotic index alterations and morphoanatomical changes in meristematic cells were observed only in the dark condition at the highest concentrations, demonstrating that light also reduces AgNPs cytotoxicity. The light-dependent aggregation of AgNPs may have reduced toxicity by reducing the uptake of these NPs by the cells. Our findings demonstrate that AgNPs can be genotoxic, cytotoxic and induce morphoanatomical and biochemical changes in A. cepa roots even at low concentrations, and that visible-light alters their aggregation state, and decreases their toxicity. We suggest that visible light can be an alternative treatment to remediate AgNP residues, minimizing their toxicity and environmental risks.
اظهر المزيد [+] اقل [-]Strong sorption of two fungicides onto biodegradable microplastics with emphasis on the negligible role of environmental factors النص الكامل
2020
Jiang, Mengyun | Hu, Liyang | Lu, Anxiang | Liang, Gang | Lin, Zuhong | Zhang, Tingting | Xu, Li | Li, Bingru | Gong, Wenwen
Microplastics have attracted much attention in recent years because they are able to interact with other pollutants including pesticides, with implications for the potential risks to biota. However, the sorption behavior of pesticides on microplastics, especially on biodegradable microplastics which are promising alternatives to conventional polymers, has been insufficiently studied. In this study, triadimefon and difenoconazole were selected as model triazole fungicides, and their sorption behavior on a typical biodegradable microplastics (PBS: polybutylene succinate) and two conventional polyethylene (PE) and polyvinyl chloride (PVC) microplastics was investigated with batch experiments in an aqueous solution. PBS presented the highest sorption capacity for triadimefon (104.2 ± 4.8 μg g⁻¹) and difenoconazole (192.8 ± 2.3 μg g⁻¹), which was 1.8- and 1.3-fold that on PE and 4.4- and 7.4-fold that of PVC, respectively. The results of sorption kinetic and isotherm modeling were better fit by a pseudo-second order model and linear model, respectively. More importantly, the effects of environmental factors (pH, salinity and dissolved organic matter) on the sorption behavior were investigated. Fungicide sorption on PBS was generally not affected by salinity, pH or dissolved organic matter. However, in contrast, salinity and dissolved organic matter both significantly decreased sorption on PE and PVC. The results showed that not only the sorption capacities of biodegradable microplastics but also their responses to environmental factors are quite different from those of conventional microplastics. This finding highlights the importance of the role played by biodegradable microplastics in the accumulation and transportation of organic pollutants.
اظهر المزيد [+] اقل [-]Distribution and superposed health risk assessment of fluorine co-effect in phosphorous chemical industrial and agricultural sources النص الكامل
2020
Yu, Ya-qi | Cui, Si-fan | Fan, Rui-jun | Fu, Yuan-zhou | Liao, Yu-liang | Yang, Jin-yan
The industrial and agricultural activities based on phosphorous can increase the F content in the surrounding area, causing a widespread adverse effect on the organisms. However, the current information on the superposed health risk posed by the multi-exposure to the F contamination in an area jointly affected by agricultural and industrial activities (DA) is limited. Herein, the F distribution in multi-environmental media and the exposure risk to humans by ingestion, inhalation, and dermal contact pathways are studied in an DA. The content of soil water-soluble fluorine (WF) was higher in the DA than in the area individually affected by agricultural activities (SA). This indicated a superposed contribution of the industrial and agricultural activities to increase the F toxicity in the soil. The correlation of the soil pH and the organic matter content with the soil WF concentration in DA suggested an inter-relationship between the soil physicochemical properties and the toxicity of F in the soil by industrial and agricultural activities. Irrigation water was not a major anthropogenic source of the cropland soil F. The large variation in F concentration in the crops (101.8–195.6%) might have originated from the discrepancies in the soil F content and air F concentration. The air F pollution (0.6–1.6 μg dm⁻² d⁻¹) in the area particularly influenced by intensive industrial activities should be important. The exposure of residents to F was mainly from the ingestion of F-enriched crops. The higher exposure of adults to F than that of children could be attributed to more industrial and agricultural outdoor activities, larger exposure area of the skin, and more daily ingestion of F-enriched food by adults. Overall, present insights into the distribution of and the multi-exposure to F may be beneficial for decreasing the adverse F effects on the residents in DAs worldwide.
اظهر المزيد [+] اقل [-]Human activities and the natural environment have induced changes in the PM2.5 concentrations in Yunnan Province, China, over the past 19 years النص الكامل
2020
Yang, Kun | Teng, Mengfan | Luo, Yi | Zhou, Xiaolu | Zhang, Miao | Sun, Weizhao | Li, Qiulin
Fine particulate matter (PM₂.₅) concentrations exhibit distinct spatiotemporal heterogeneity, mainly due to the natural environment and human activities. Yunnan Province of China was selected as the research area, and a real-time measured PM₂.₅ concentration dataset was acquired from 41 monitoring stations in 16 major cities from February 2013 to December 2018. Aerosol optical depth (AOD) products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and data on four meteorological variables from 2000 to 2018 were employed. A novel hybrid model was constructed to estimate the historical missing PM₂.₅ values from 2000 to 2012, calculate the missing PM₂.₅ concentrations from 2012 to 2014 in some major cities, and analyze the driving factors of the PM₂.₅ concentration changes and causes of key pollution events in Yunnan Province over the past 19 years. The temporal analysis results indicate that the annual mean PM₂.₅ concentration in Yunnan Province exhibited three stages: continuous stability, a rapid increase and a rapid decrease. The year 2013 was an important breakpoint in the trend of the concentration change. The spatial analysis results reveal that the annual mean PM₂.₅ concentration in the north was lower than that in the south, and there was a significant difference between the east and the west. In addition, springtime biomass burning in Southeast Asia was found to be the main cause of PM₂.₅ pollution in Yunnan Province in spring.
اظهر المزيد [+] اقل [-]Usability of the bivalves Dreissena polymorpha and Anodonta anatina for a biosurvey of the neurotoxin BMAA in freshwater ecosystems النص الكامل
2020
Lepoutre, A. | Hervieux, J. | Faassen, E.J. | Zweers, A.J. | Lurling, M. | Geffard, A. | Lance, E.
Usability of the bivalves Dreissena polymorpha and Anodonta anatina for a biosurvey of the neurotoxin BMAA in freshwater ecosystems النص الكامل
2020
Lepoutre, A. | Hervieux, J. | Faassen, E.J. | Zweers, A.J. | Lurling, M. | Geffard, A. | Lance, E.
The environmental neurotoxin β-methylamino-L-alanine (BMAA) may represent a risk for human health in case of chronic exposure or after short-term exposure during embryo development. BMAA accumulates in freshwater and marine organisms consumed by humans. It is produced by marine and freshwater phytoplankton species, but the range of producers remains unknown. Therefore, analysing the phytoplankton composition is not sufficient to inform about the risk of freshwater contamination by BMAA. Filter-feeders mussels have accumulation capacities and therefore appear to be relevant to monitor various pollutants in aquatic ecosystems. We investigated the suitability of the freshwater mussels Dreissena polymorpha and Anodonta anatina for monitoring BMAA in water. Both species were exposed to 1, 10, and 50 μg of dissolved BMAA/L daily for 21 days, followed by 42 days of depuration in clean water. On days 0, 1, 7, 14, and 21 of exposure and 1, 7, 14, 21 and 42 of depuration, whole D. polymorpha and digestive glands of A. anatina were sampled, and the total BMAA concentration was measured. D. polymorpha accumulated BMAA earlier (from day 1 at all concentrations) and at higher tissue concentrations than A. anatina, which accumulated BMAA from day 14 when exposed to 10 μg BMAA/L and from day 7 when exposed to 50 μg BMAA/L. As BMAA accumulation by D. polymorpha was time and concentration-dependent, with a significant elimination during the depuration period, this species may be able to reflect the levels and dynamics of water contamination by dissolved BMAA. The species A. anatina could be used for monitoring water concentrations above 10 μg BMAA/L.
اظهر المزيد [+] اقل [-]Usability of the bivalves Dreissena polymorpha and Anodonta anatina for a biosurvey of the neurotoxin BMAA in freshwater ecosystems النص الكامل
2020
Lepoutre, A. | Hervieux, J. | Faassen, E.J. | Zweers, A.J. | Lurling, M. | Geffard, A. | Lance, E.
The environmental neurotoxin β-methylamino-L-alanine (BMAA) may represent a risk for human health in case of chronic exposure or after short-term exposure during embryo development. BMAA accumulates in freshwater and marine organisms consumed by humans. It is produced by marine and freshwater phytoplankton species, but the range of producers remains unknown. Therefore, analysing the phytoplankton composition is not sufficient to inform about the risk of freshwater contamination by BMAA. Filter-feeders mussels have accumulation capacities and therefore appear to be relevant to monitor various pollutants in aquatic ecosystems. We investigated the suitability of the freshwater mussels Dreissena polymorpha and Anodonta anatina for monitoring BMAA in water. Both species were exposed to 1, 10, and 50 μg of dissolved BMAA/L daily for 21 days, followed by 42 days of depuration in clean water. On days 0, 1, 7, 14, and 21 of exposure and 1, 7, 14, 21 and 42 of depuration, whole D. polymorpha and digestive glands of A. anatina were sampled, and the total BMAA concentration was measured. D. polymorpha accumulated BMAA earlier (from day 1 at all concentrations) and at higher tissue concentrations than A. anatina, which accumulated BMAA from day 14 when exposed to 10 μg BMAA/L and from day 7 when exposed to 50 μg BMAA/L. As BMAA accumulation by D. polymorpha was time and concentration-dependent, with a significant elimination during the depuration period, this species may be able to reflect the levels and dynamics of water contamination by dissolved BMAA. The species A. anatina could be used for monitoring water concentrations above 10 μg BMAA/L. D. polymorpha and A. anatina could be used to biomonitor BMAA in fresh water.
اظهر المزيد [+] اقل [-]Multidisciplinary approach to determine the effect of polybrominated diphenyl ethers on gut microbiota النص الكامل
2020
Cruz, Rebeca | Palmeira, Josman D. | Martins, Zita E. | Faria, Miguel A. | Ferreira, Helena | Marques, António | Casal, Susana | Cunha, Sara C.
Environmental health is increasingly compromised by persistent toxic substances, which may have serious implications in food safety and, thus, in human health. Polybrominated diphenyl ethers (PBDEs) are anthropogenic contaminants with endocrine disruption abilities and are commonly found in seafood, the main route of human exposure. Growing evidence points out that the human gut microbiota interacts with xenobiotics, which may lead to impairment of host homeostasis if functions of microbiota become compromised. The aim of this study was to ascertain if the physiological balance of human gut microbiome is affected by the presence and degree of exposure to PBDEs. Fermentation was performed in a batch closed-system using an inoculum made from fresh human stool. The volatolomic profile was analysed by solid-phase microextraction coupled to gas chromatography-mass spectrometry. Mesophilic, Gram-negative bacteria and coliforms were quantified by classic plating methods. Changes in the gut microbiome were evaluated after DNA extraction followed by deep sequencing of the 16S rDNA region. The exposure to PBDEs resulted in an imbalance in sulfur, short-chain fatty acids and aromatic organic compounds, changing the microbial volatolome in a dose- and time-dependent manner. Slight deviations in the microbial structure of human gut occurred in the presence of PBDEs, especially for high doses of exposure. For the first time, the impact of PBDEs on the microbial homeostasis of human gut microbiota was taken into consideration, revealing noteworthy modifications with serious health implications even at oral exposure doses considered as safe by worldwide regulatory entities.
اظهر المزيد [+] اقل [-]The pigmentation interference of bisphenol F and bisphenol A النص الكامل
2020
Mu, Xiyan | Liu, Jia | Yuan, Lilai | Huang, Ying | Qian, Le | Wang, Chengju
Bisphenol A (BPA) and bisphenol F (BPF) are widely distributed in the environment and daily consumptions, leading to exposure toward human and environmental animals. The potential risk of bisphenol analogs on pigment and skin health is not well documented. In this study, we found that 0.05 mg/L BPF (tolerated daily intake (TDI) value of BPA) affected the particle size and color density of zebrafish melanin. While BPA caused less depigmentation effect toward zebrafish with effective concentration of 5.0 mg/L. The downregulation of melanin synthases induced by BPF is associated with the reduction in melanin. Molecular dynamics indicated that both BPF and BPA could act as ligands of zebrafish and human Tyr family proteins; however, these compounds have completely different energetics and spatial steric effects, potentially explaining their varying depigmentation effects. Additionally, an in vitro assay using A375 melanoma cells demonstrated that the inhibitory effect of BPF on human melanin production was primarily attributed to Tyr inhibition. These findings provide an important basis for understanding the molecular mechanisms of BPF and BPA in melanin inhibition, and the results reflect the skin pigmentation interference risk of these compounds, which are ubiquitous in everyday personal products.
اظهر المزيد [+] اقل [-]The mediation effect of maternal glucose on the association between ambient air pollution and birth weight in Foshan, China النص الكامل
2020
Yang, Yin | Lin, Qingmei | Liang, Ying | Ruan, Zengliang | Qian, Zhengmin (Min) | Syberg, Kevin M. | Howard, Steven W. | Wang, Changke | Acharya, Bipin | Zhang, Qihao | Ge, Haibo | Wu, Xueli | Li, Kaihua | Guo, Xiaoling | Lin, Hualiang
Maternal blood glucose level is associated with fetal growth, therefore, its role in the associations between air pollution and birth weight deserves investigation. We examined the mediation effect of maternal blood glucose on the associations between maternal air pollution exposure and birth weight. A total of 10,904 pregnant women in Foshan, China during 2015–2019 were recruited. Oral glucose tolerance test (OGTT) was administered to each participant after late trimester 2. Air pollution data at the monitoring stations in residential districts was used to estimate exposures of each participant during trimester 1 and trimester 2. Mixed-effects linear models were used to estimate the associations between air pollution and birth weight. After controlling for ten covariates, the direct effect of PM₂.₅ and SO₂ (each 10 μg/m³ increment) on birth weight was −15.7 g (95% CI: −29.4, −4.8 g) and −83.6 g (95% CI: −134.8, −33.0 g) during trimester 1. The indirect effect of PM₂.₅ and SO₂ (each 10 μg/m³ increment) on birth weight by increasing maternal fasting glucose level was 6.6 g (95% CI: 4.6, 9.1 g) and 22.0 g (95% CI: 4.1, 44.0 g) during trimester 1. Our findings suggest that air pollution might affect the birth weight through direct and indirect pathway, and the indirect effect might be mediated by maternal blood glucose.
اظهر المزيد [+] اقل [-]Accumulation of halogenated polycyclic aromatic hydrocarbons by different tuna species, determined by high-resolution gas chromatography Orbitrap mass spectrometry النص الكامل
2020
Wickrama-Arachchige, A Upasanta-Kumara | Hirabayashi, Takuma | Imai, Yuki | Guruge, Keerthi S. | Dharmaratne, Tilak S. | Ohura, Takeshi
Halogenated polycyclic aromatic hydrocarbon (HPAH) concentrations in tissues from three tuna species Thunnus albacares (yellowfin tuna), Katsuwonus pelamis (skipjack tuna), and Auxis thazard (frigate tuna) were determined by high-resolution gas chromatography Orbitrap mass spectrometry. The tuna samples were collected from the Indian Ocean. The instrument conditions gave high mass accuracy at 0.9 m/z isolation width of the mass filter and a mass error of <±1.0 ppm for many HPAHs. A total of 29 of the 30 targets chlorinated PAHs (ClPAHs) and 20 of the 21 targets brominated PAHs (BrPAHs) were detected in the tuna muscle samples. The mean total ClPAH, BrPAH and PAH concentrations for tuna were 127.2, 156.6 and 682.8 ng/g lipid weight, respectively. The mean total ClPAH and BrPAH concentrations (ng/g lipid weight) in the tuna were considerably lower than that of PAH concentrations. The mean total ClPAH, BrPAH and PAH concentrations in T. albacares respectively were 185.8, 249.2 and 784.1 ng/g lipid weight, irrespective of the body sizes. The mean total ClPAH, BrPAH and PAH concentrations in K. pelamis respectively were 45.1, 24.8 and 555.6 ng/g lipid weight. The mean total ClPAH, BrPAH and PAH concentrations in A. thazard respectively were 34.09, 4.73 and 433.24 ng/g lipid weight. The total ClPAH concentrations and body weights significantly positively correlated for T. albacares. The mean total ClPAH concentration in white muscles was significantly higher (p < 0.05) for large than for small T. albacares. This suggests ClPAHs could bioaccumulate in T. albacares, possibly because they are poorly metabolized. The chlorinated phenanthrene and pyrene concentrations indicated tuna accumulate these compounds increasingly effectively as the tuna grow. This was the first time large numbers of HPAHs were found in biological samples. HPAHs may adversely affect the health of humans consuming tuna.
اظهر المزيد [+] اقل [-]PM2.5 from a broiler breeding production system: The characteristics and microbial community analysis النص الكامل
2020
Dai, Pengyuan | Shen, Dan | Tang, Qian | Huang, Kai | Li, Chunmei
Particulate matter (PM) released from the processes of livestock production has a negative impact on the health of animals and workers. Herein, the concentration, major chemical components, morphology and microbiological compositions of particulate matter 2.5 (PM2.5, particles with aerodynamic diameter less than 2.5 μm) in a broiler breeding house were investigated. The results showed that the PM2.5 distribution in the chicken house was affected by the illumination, draught fans, chicken frame structure and activity of the chickens in the broiler breeding house. Component analysis showed that organic carbon (OC) accounted for the largest proportion, and followed by element carbon (EC), SO42−, NO3−, NH4+, Na+, K+ and Ca2+. Ultrastructural observations revealed that the shape of PM2.5 had a round, rectangular, chain-like and irregular shape. The concentration of endotoxin was approximately 0.3 EU/m3. Microbiological analysis showed that at the genus level, the pathogenic bacteria included Staphylococcus, Corynebacterium, Enterococcus, Parabacteroides, Escherichia and Megamonas. The abundant harmful fungi were Aspergillus, Scopulariopsis, Wallemia, and Fusarium. Through redundancy analysis (RDA) analysis, we determined that OC, EC, Na+, K+, and NH4+ had strong correlations with Brachybacterium, Brevibacterium, Corynebacterium, Escherichia, Scopulariopsis and Microascus. SO42− was closely related to Scopulariopsis and Salinicoccus. Salinicoccus was also strongly correlated with NO3−. Our results indicated that feed, faeces, and outside soot are contributed to the increase in PM2.5 concentration in the chicken house, while the sources of the dominant bacterial and fungi might be feed, faeces, suspended outside soil and cereal crops.
اظهر المزيد [+] اقل [-]