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Qixing Zhou - One of the best experts on this subject based on the ideXlab platform.

  • genotoxicity of tetracycline as an Emerging Pollutant on root meristem cells of wheat triticum aestivum l
    Environmental Toxicology, 2011
    Co-Authors: Xiujie Xie, Qixing Zhou, Qiuhua Bao, Yanyu Bao
    Abstract:

    Increasing attention has been paid to antibiotic contamination as an increasingly serious environmental issue. Tetracycline has been widely used for decades in human and veterinary medicines, with incremental residues in the environment and adverse influences on living organisms. In the present study, the genetic toxicity of tetracycline was investigated using a bioassay method with wheat (Triticum aestivum L.) root-meristem cells at a concentration range of 0.25-300 mg L(-1) and exposure times of 24, 48, and 72 h. The results indicated that tetracycline at lower concentrations (0.25-1 mg L(-1) ) stimulated cell mitotic division, whereas at 50-300 mg L(-1) concentration caused a concentration-related decrease in mitotic index (MI). The lower tetracycline concentrations induced a slight increase in the frequency of micronucleus (MN), chromosomal aberration (CA), and sister chromatid exchange (SCE) in wheat root tips. However, there were significant increases in these indices at higher concentrations in concentration- and time-dependent manners, including the frequencies of MN (25-200 mg L(-1) ), CA (10-200 mg L(-1) ), and SCE (5-200 mg L(-1) ), respectively. The inducement of MN, CA, and SCE decreased at 250 and 300 mg L(-1) due to acute cell toxicity for all tested times. Comparatively, SCE was the most sensitive, followed by CA, with MN the least sensitive to the genotoxicity of tetracycline in wheat. These results imply that tetracycline may be genotoxic to plant cells, and exposure to tetracycline may pose a genotoxic risk to living organisms. The results also suggest that the wheat bioassay was efficient, simple, and reproducible in monitoring the genotoxicity of tetracycline in the environment.

  • potential biochemical and genetic toxicity of triclosan as an Emerging Pollutant on earthworms eisenia fetida
    Chemosphere, 2010
    Co-Authors: Qixing Zhou
    Abstract:

    Triclosan as an important antimicrobial agent is increasingly detected in the terrestrial environment as sewage sludge and reclaimed water are applied on land, but little is known about its effect on non-target soil organisms. In this study, biochemical responses including changes in the activity of catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), and malondialdehyde (MDA) of the earthworm Eisenia fetida were examined in order to assess ecological toxicity of the chemical. The single-cell gel electrophoresis (SCGE) was also used to measure the potential genotoxicity of the chemical. The results showed that the activity of CAT and GST at the highest tested dose could be stimulated after a 2-d exposure, reaching 148% and 123% of that in the control, respectively. However, with prolonged exposure, the activity of CAT and GST at the highest tested dose was inhibited, falling to 47% and 33% of that in the control, respectively. Triclosan induced an increase in the activity of SOD, but no significant (p > 0.05) changes were observed. The content of MDA was dependent both on the dose of triclosan and on the exposure duration. The comet assay demonstrated that triclosan treatments led to a dose-dependent DNA damage of E. fetida after exposures of 7 and 14 d. Our findings can suggest that triclosan has sublethal effects on E. fetida.

  • physiological and potential genetic toxicity of chlortetracycline as an Emerging Pollutant in wheat triticum aestivum l
    Environmental Toxicology and Chemistry, 2010
    Co-Authors: Xiujie Xie, Qixing Zhou, Yanyu Bao
    Abstract:

    Increasing attention is now being paid to antibiotic contamination as a serious environmental issue. Chlortetracycline has been widely used for decades as a human and veterinary medicine, which has resulted in environmental residues and damage to living organisms. In the present study, the physiological and potential genetic toxicity of chlortetracycline was investigated using a wheat (Triticum aestivum L.) bioassay at a concentration range of 0.0625 to 300 mg/L and an exposure time of 24, 48, and 72 h. The results indicated that chlortetracycline at the lower concentrations stimulated germination and cell mitotic division and growth, whereas higher concentrations significantly inhibited processes such as bud length (50–300 mg/L), percentage germination (25–300 mg/L), root length (25–300 mg/L), and mitotic index (MI) (25–300 mg/L). The lowest concentration of chlortetracycline slightly augmented the frequency of micronucleus (MN), chomosomal aberration (CA), and sister chomatid exchange (SCE) in the root tips; however, significant (p < 0.05 and 0.01) levels of augmentation were observed at higher concentrations in a concentration-dependent manner, including the frequencies of MN (25–200 mg/L), CA (10–200 mg/L), and SCE (5–200 mg/L), respectively. The inducement of MN, CA, and SCE decreased at 250 and 300 mg/L as a result of acute cell toxicity. In addition, all endpoints showed a time-dependent increase at 0.0625 to 200 mg/L. These results imply that chlortetracycline (≥5 mg/L) may be genotoxic to plant cells, and exposure to chlortetracycline may pose a potential genotoxic risk to living organisms. Comparatively, SCE was the most sensitive, followed by CA, and MN was the least sensitive to chlortetracycline genotoxicity in wheat. The results also suggest that the wheat bioassay is efficient, simple, and reproducible for monitoring the genotoxicity of chlortetracycline in the environment. Environ. Toxicol. Chem. 2010;29:922–928. © 2009 SETAC

  • effects of tetrabromobisphenol a as an Emerging Pollutant on wheat triticum aestivum at biochemical levels
    Chemosphere, 2008
    Co-Authors: Qixing Zhou, Xiaoling Liu, Yi Luo
    Abstract:

    Biochemical responses of wheat (Triticum aestivum) to the stress of tetrabromobisphenol A (TBBPA) as an Emerging Pollutant were examined. The results indicated that reduction of the chlorophyll (CHL) content in wheat leaves Could be observed. However, the changes in the CHL content with the increasing TBBPA concentration from 50 to 5000 mg kg(-1) were insignificant (p > 0.05). Increased malondialdehyde levels were detected in wheat leaves after both 7-d and 12-d exposures. The changes in the activity of superoxide disumtases (SOD), peroxidases (POD) and catalases (CAT) in wheat leaves irregularly fluctuated with time as the TBBPA concentration increased. However, significant (p < 0.05) decrease in the activity of POD and CAT treated with 500 and 5000 mg kg(-1) TBBPA could be observed. Our data also showed that the plant has the capacity to tolerate the oxidative stress, but the capacity Would be lost with prolonged exposure and increasing TBBPA concentration. There were no dose-response effects in the changes between the activity of antioxidant enzymes (SOD, POD and CAT) and the concentration of TBBPA. The decrease in the activity of POD and CAT could be considered as good biomarkers of serious stress by TBBPA in soil environment. (c) 2008 Elsevier Ltd. All rights reserved.

A Bahamonde - One of the best experts on this subject based on the ideXlab platform.

  • tio2 rgo photocatalytic degradation of an Emerging Pollutant kinetic modelling and determination of intrinsic kinetic parameters
    Journal of environmental chemical engineering, 2019
    Co-Authors: A Tolosanamoranchel, Agustina Manassero, María Lucila Satuf, Orlando Mario Alfano, Jose A Casas, A Bahamonde
    Abstract:

    Abstract An intrinsic kinetic model, derived from a suggested reaction photo-mechanism and with an explicit dependence on the local volumetric rate of photon absorption (LVRPA), was developed to simulate the photocatalytic degradation of clofibric acid and the main reaction intermediates, with a new titania-reduced graphene oxide nanocomposite (TiO2-rGO), The proposed reaction mechanism takes into account that graphene behaves as an electron acceptor and, therefore, this effect was included in the derivation of the reaction rate expressions and in the parameters estimation of the kinetic model. The photodegradation of clofibric acid was performed in a slurry photoreactor under different irradiation levels and using several loadings of a TiO2-rGO nanocomposite, prepared by hydrothermal method with a 0.5 wt. % of GO. Absorbed radiation profiles inside the photoreactor were obtained by solving the radiation model with the Monte Carlo method. A photocatalyst loading of 100 mg L−1 gave place to the best photodegradation results. Mass balances were proposed for the main Pollutant and their main detected intermediates: p-benzoquinone and 4-chlorophenol. The intrinsic kinetic parameters were obtained for the complete (6-parameters) and simplified (5-parameters) models by comparing the experimental and the theoretical concentration values of all the organic compounds detected. The model proved to be able to predict with good accuracy the concentration evolution of clofibric acid, 4-chlorophenol and p-benzoquinone under several photocatalyst concentrations and irradiation levels. Finally, a very good correlation between calculated and experimental values of clofibric acid concentration was obtained with root-mean-square errors below 11%.

  • influence of tio2 rgo optical properties on the photocatalytic activity and efficiency to photodegrade an Emerging Pollutant
    Applied Catalysis B-environmental, 2019
    Co-Authors: A Tolosanamoranchel, Agustina Manassero, María Lucila Satuf, Orlando Mario Alfano, Jose A Casas, A Bahamonde
    Abstract:

    Abstract TiO2-reduced graphene oxide (TiO2-rGO) photocatalysts with different mass ratios (GO:TiO2 0.1-0.5-1%) were synthesized via a hydrothermal method and compared through their physico-chemical properties and photocatalytic activity in the degradation of an Emerging contaminant, clofibric acid. The optical properties of the TiO2-rGO nanocomposites were first estimated in order to calculate the local volumetric rate of photon absorption inside a photocatalytic reactor. Radiation models were solved using the Monte Carlo method. The effect of rGO as well as the photocatalyst loadings on the radiation absorption was evaluated. The lowest photodegradation rate found in P25-rGO 1% was ascribed to an excess of rGO that could well favor charge carriers recombination leading to detrimental photoactivity. A GO/TiO2 mass ratio of 0.5% provided the fastest initial photodegradation rate under the operating conditions studied here. Finally, the photo-efficiency of all these photocatalysts was also analyzed by calculating the quantum efficiency parameter. The highest value of quantum efficiency was achieved with P25-rGO 0.5% at 100 mg L−1, with an increase of 11% compared to the value obtained for P25-rGO 0%.

Xu Zhang - One of the best experts on this subject based on the ideXlab platform.

  • toxicity of new Emerging Pollutant tris 2 3 dibromopropyl isocyanurate on balb c mice
    Journal of Applied Toxicology, 2015
    Co-Authors: Xu Zhang, Jieqing Bao, Yuchen Liu, Yong Liang, Jie Zhang, Aiqian Zhang
    Abstract:

    The Emerging heterocyclic brominated flame retardant tris-(2,3-dibromopropyl) isocyanurate (TBC), widely used in reinforced plastics, has demonstrated toxicity to fish. However, little is known about its toxicity in rodents. This study aims to determine the effect of TBC on growth, biochemical parameters in serum, organs and related gene expression of both male and female BALB/c mice after gastro-gavage administration of 0, 2, 10 and 50mgkg(-1) TBC for 28days. Results indicated that exposure to TBC had no effects on basic growth and food intake of mice, but significantly increased serum alanine aminotransferase levels in male mice. Histopathological analyses showed that focal necrosis (2, 10 and 50mgkg(-1) TBC-exposed groups) and ballooning degeneration (10 and 50mgkg(-1) TBC-exposed groups) were found in mouse liver, whereas transmission electron microscopy revealed dose-dependent hepatocyte apoptosis, mitochondrial degeneration and endoplasmic reticulum dilation. Histopathological and ultrastructural assessments in the lung showed dose-dependent hyperplasia of pulmonary alveolar epithelium, bronchial congestion, infiltration of inflammatory cells and mitochondrial swelling following TBC exposure. Our results also indicated that mitochondria are one of the major target cytoplasmic organelles for TBC, suggesting that damage in mitochondria is one of the pathways that led to toxic effects in the liver and lung of TBC-treated groups. Moreover, TBC effectively activated the gene expression of p53 in mice liver. Our findings provide strong evidence that TBC induces significant toxicity in mice organs, especially in liver and lung, which play vital roles in detoxification and gas exchange, respectively. This research will contribute to characterize the toxic effects of TBC, which was introduced as one of the candidates for brominated flame retardant replacement. Copyright (c) 2014 John Wiley & Sons, Ltd. Tris-(2,3-dibromopropyl) isocyanurate (TBC) exposure had no effects on basic growth or food intake of mice, whereas significantly increased alanine aminotransferase serum levels. TBC exposure induced p53 expression in mouse liver, and altered the ultrastructure in liver and lung. Results also indicated that mitochondria are one of the major target cytoplasmic organelles for TBC. These findings suggest that damage in mitochondria is one of the pathways that lead to toxic effects in the liver and lung of TBC-treated groups.

Yan Zhou - One of the best experts on this subject based on the ideXlab platform.

  • catalytic degradation of diatrizoate by persulfate activation with peanut shell biochar supported nano zero valent iron in aqueous solution
    International Journal of Environmental Research and Public Health, 2018
    Co-Authors: Xueliang Zhang, Cheng Sun, Yuxuan Dai, Shaogui Yang, Yusuo Lin, Xinhua Zhan, Yan Zhou
    Abstract:

    An Emerging Pollutant, diatrizoate (DTZ) has been frequently detected in aqueous solution. Unique reticular peanut shell biochar (BC)-supported nano zero-valent iron (nZVI) composite (nZVI/BC) was successfully synthesized and used as a catalyst for activating persulfate (PS) to promote the removal of DTZ. The structure and morphology of the nanocomposite materials were characterized by scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller measurements, and Fourier transform infrared spectroscopy. The degradation of DTZ (20 mg L−1) was achieved by activating PS with the nanocomposite material. The removal of DTZ reached nearly 100% using 25 mM PS and 0.45 g L−1 nZVI/2BC (mass ratio of nZVI and BC at 1:2) nanocomposite material at pH 3.0 and 25 °C. Influencing factors, such as dosages of nZVI/2BC and PS, temperature, and pH were also investigated. The mechanisms of PS activation with nZVI/2BC were discussed, including BC property, electron transfer, and the identification of free radicals in the reaction. The findings demonstrated that nZVI/BC-PS (peanut shell BC-supported nZVI activating PS) is a promising material for the treatment of refractory organic Pollutants.

  • Catalytic Degradation of Diatrizoate by Persulfate Activation with Peanut Shell Biochar-Supported Nano Zero-Valent Iron in Aqueous Solution
    MDPI AG, 2018
    Co-Authors: Xueliang Zhang, Cheng Sun, Yuxuan Dai, Shaogui Yang, Yusuo Lin, Xinhua Zhan, Yan Zhou
    Abstract:

    An Emerging Pollutant, diatrizoate (DTZ) has been frequently detected in aqueous solution. Unique reticular peanut shell biochar (BC)-supported nano zero-valent iron (nZVI) composite (nZVI/BC) was successfully synthesized and used as a catalyst for activating persulfate (PS) to promote the removal of DTZ. The structure and morphology of the nanocomposite materials were characterized by scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller measurements, and Fourier transform infrared spectroscopy. The degradation of DTZ (20 mg L−1) was achieved by activating PS with the nanocomposite material. The removal of DTZ reached nearly 100% using 25 mM PS and 0.45 g L−1 nZVI/2BC (mass ratio of nZVI and BC at 1:2) nanocomposite material at pH 3.0 and 25 °C. Influencing factors, such as dosages of nZVI/2BC and PS, temperature, and pH were also investigated. The mechanisms of PS activation with nZVI/2BC were discussed, including BC property, electron transfer, and the identification of free radicals in the reaction. The findings demonstrated that nZVI/BC-PS (peanut shell BC-supported nZVI activating PS) is a promising material for the treatment of refractory organic Pollutants

Jun Wang - One of the best experts on this subject based on the ideXlab platform.

  • microplastics pollution in inland freshwaters of china a case study in urban surface waters of wuhan china
    Science of The Total Environment, 2017
    Co-Authors: Wenfeng Wang, Anne Wairimu Ndungu, Zhen Li, Jun Wang
    Abstract:

    Abstract Microplastics have been considered as an Emerging Pollutant in the aquatic environment. However, research about microplastic pollution in inland freshwaters of China is insufficient. The present study investigated the levels of microplastics in surface water of 20 urban lakes and urban reaches of the Hanjiang River and Yangtze River of Wuhan, the largest city in central China. Microplastic concentrations ranged from 1660.0 ± 639.1 to 8925 ± 1591 n/m 3 for the studied waters, with the highest concentration found in Bei Lake. Microplastic abundance in lakes varied markedly in space, and negatively correlated with the distance from the city center ( p

  • microplastics pollution in inland freshwaters of china a case study in urban surface waters of wuhan china
    Science of The Total Environment, 2017
    Co-Authors: Wenfeng Wang, Anne Wairimu Ndungu, Jun Wang
    Abstract:

    Microplastics have been considered as an Emerging Pollutant in the aquatic environment. However, research about microplastic pollution in inland freshwaters of China is insufficient. The present study investigated the levels of microplastics in surface water of 20 urban lakes and urban reaches of the Hanjiang River and Yangtze River of Wuhan, the largest city in central China. Microplastic concentrations ranged from 1660.0±639.1 to 8925±1591n/m3 for the studied waters, with the highest concentration found in Bei Lake. Microplastic abundance in lakes varied markedly in space, and negatively correlated with the distance from the city center (p<0.001), which confirmed the important role of anthropogenic factors in microplastic distribution. Urban reaches of the Hanjiang River and Yangtze River were found to have relatively lower levels of microplastics than most of the studied lakes. The major type of microplastics among the studied waters was colored plastic, with fiber being the most frequent shape. More than 80% of microplastics in number had a size of <2mm. Polyethylene terephthalate and polypropylene were the dominant polymer-types of microplastics analyzed. This study provided important reference for better understanding microplastic levels in inland freshwaters.