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Effects of As2O3 on DNA methylation, genomic instability, and LTR retrotransposon polymorphism in Zea mays
2015
Erturk, Filiz Aygun | Aydın, Murat | Sigmaz, Burcu | Taspinar, M Sinan | Arslan, Esra | Agar, Guleray | Yagci, Semra
Arsenic is a well-known toxic substance on the living organisms. However, limited efforts have been made to study its DNA methylation, genomic instability, and long terminal repeat (LTR) retrotransposon polymorphism causing properties in different crops. In the present study, effects of As₂O₃ (arsenic trioxide) on LTR retrotransposon polymorphism and DNA methylation as well as DNA damage in Zea mays seedlings were investigated. The results showed that all of arsenic doses caused a decreasing genomic template stability (GTS) and an increasing Random Amplified Polymorphic DNAs (RAPDs) profile changes (DNA damage). In addition, increasing DNA methylation and LTR retrotransposon polymorphism characterized a model to explain the epigenetically changes in the gene expression were also found. The results of this experiment have clearly shown that arsenic has epigenetic effect as well as its genotoxic effect. Especially, the increasing of polymorphism of some LTR retrotransposon under arsenic stress may be a part of the defense system against the stress.
显示更多 [+] 显示较少 [-]Passive air sampling for determining the levels of ambient PCDD/Fs and their seasonal and spatial variations and inhalation risk in Shanghai, China
2015
Tian, Yajun | Nie, Zhiqiang | Tian, Shulei | Liu, Feng | He, Jie | Yang, Yufei | Wang, Xingrun | Die, Qingqi | Fang, Yanyan | Huang, Qifei
The seasonal and spatial variations, compositional profiles, and possible sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in ambient air samples in Shanghai of China were investigated by passive air samplers, and the potential inhalation risks posed by these chemicals were evaluated. The following results were obtained: (1) The World Health Organization (WHO) toxic equivalency (TEQ) values for PCDD/Fs were in the range of 10.8–259 fg m⁻³ (mean 63.4 fg m⁻³) in summer and 24.1–154 fg m⁻³ (mean 83.4 fg m⁻³) in winter. Atmospheric PCDD/F levels were in the following order: industrial areas > commercial and residential areas > rural areas. (2) 2,3,4,7,8-PeCDF (24 %), 2,3,7,8-TeCDD (16 %), 1,2,3,7,8-PeCDD (13 %), and 2,3,7,8-TeCDF (12 %) were the predominant contributors to the TEQ of PCDD/Fs. (3) There was a slight seasonal trend with higher TEQ values in winter than in summer, which could be related to seasonal variations in the dispersion of PCDD/Fs in ambient air. (4) The children’s daily intake was at the lower end of the range for the tolerable daily intake of PCDD/Fs recommended by WHO, which indicates that the inhalation risk of PCDD/Fs for local residents in Shanghai is relatively low.
显示更多 [+] 显示较少 [-]Evaluating the risk of mixtures in the indoor air of primary school classrooms
2015
Mishra, Nitika | Ayoko, G. A. (Godwin A.) | Salthammer, Tunga | Morawska, L. (Lidia)
In school environments, children are constantly exposed to mixtures of airborne substances, derived from a variety of sources, both in the classroom and in the school surroundings. It is important to evaluate the hazardous properties of these mixtures, in order to conduct risk assessments of their impact on children’s health. Within this context, through the application of a maximum cumulative ratio approach, this study aimed to explore whether health risks due to indoor air mixtures are driven by a single substance or are due to cumulative exposure to various substances. This methodology requires knowledge of the concentration of substances in the air mixture, together with a health-related weighting factor (i.e. reference concentration or lowest concentration of interest), which is necessary to calculate the hazard index. Maximum cumulative ratio and hazard index values were then used to categorise the mixtures into four groups, based on their hazard potential and therefore appropriate risk management strategies. Air samples were collected from classrooms in 25 primary schools in Brisbane, Australia. Analysis was conducted based on the measured concentration of these substances in about 300 air samples. The results showed that in 92 % of the schools, indoor air mixtures belonged to the ‘low concern’ group, and therefore, they did not require any further assessment. In the remaining schools, toxicity was mainly governed by a single substance, with a very small number of schools having a multiple substance mix which required a combined risk assessment. The proposed approach enables the identification of such schools and thus aids in the efficient health risk management of pollution emissions and air quality in the school environment.
显示更多 [+] 显示较少 [-]Spatial distribution and toxicity assessment of heavy metals in sediments of Liaohe River, northeast China
2015
He, Yan | Meng, Wei | Xu, Jian | Zhang, Yuan | Liu, Sisi | Guo, Changsheng
Twenty-four surface sediment samples were collected from Liaohe River in June 2014 for the analysis of total concentrations of Cu, Pb, Zn, Cd, Ni, Fe, and Mn. The spatial distribution of heavy metals in Liaohe River was site specific, with Hun River as the most polluted river mainly affected by industrial and human activities. The contents of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEMs) in Liaohe River varied significantly, ranging from 0.03 to 19.4 μmol/g and 0.14 to 10.8 μmol/g, respectively. Sulfate-reducing bacteria (SRB) community size, organic matter and sulfate availability, and sediment redox status may be the main factors affecting the AVS distribution. Among all the acid-extracted metals, Zn was dominant in all samples, whereas much more toxic Cd contributed less than 1.0 % to the total SEMs. Sediment quality guidelines (SQGs) and AVS-SEM models were used to predict the sediment toxicity. Results revealed that only a small portion of sites exhibited potential metal toxicity to aquatic biota, while adverse effects should rarely occur in majority of sites. Comparison of the two assessment methods showed inconsistent results, indicating that each method had its own limitations. The combination of different methods will be more convincing as to the sediment quality assessment.
显示更多 [+] 显示较少 [-]The endocrine-disrupting effect and other physiological responses of municipal effluent on the clam Ruditapes decussatus
2015
Mezghani-Chaari, Sawssan | Machreki-Ajmi, Monia | Tremolet, Gauthier | Kellner, Kristell | Geffard, Alain | Minier, Christophe | Hamza-Chaffai, Amel
In order to document the potential endocrine disrupting and toxic effect of the municipal wastewater effluents discharged into the Sfax coastal area (South of Tunisia), specimens of clam R. decussatus were collected from a reference site and were in vivo exposed to treated sewage effluent for 30 days. To this end, estrogenic and androgenic activities were measured in the gills to assess potential accumulation and regulation of active compounds. After effluent exposure androgenic activity in organic extracts increased up to fivefold compared to controls and remained elevated, while estrogenic activity was not significantly affected by exposure. As a consequence, remarkable disruptions in the gametogenesis activity, glycogen content, and Vitellogenin-like protein levels in male clams were observed. A parallel analysis of heavy metals in clam tissues was determined. A significant uptake of Ni, Zn, and Pb in soft tissues of exposed clams was observed. The significant increase of malondialdehyde (MDA) concentrations as a function of exposure time implies that clams have been exposed to an oxidative stress probably due to the presence of high metal concentrations in sewage effluent. Correlation analysis has revealed a statistically significant and positive relationship between MDA levels and metal concentrations in clams’ tissues. The acetylcholinesterase activity was not significantly affected by exposure. Altogether, these results showed that a short-term exposure to a mixture of chemical compounds released by the Sfax wastewater treatment plant induce adverse physiological and reproductive effects in R. decussatus. Further studies are underway in order to evaluate its long-term impacts on aquatic wildlife in the gulf of Gabes area.
显示更多 [+] 显示较少 [-]Influence of relative humidity on VOC concentrations in indoor air
2015
Markowicz, Pawel | Larsson, Lennart
Volatile organic compounds (VOCs) may be emitted from surfaces indoors leading to compromised air quality. This study scrutinized the influence of relative humidity (RH) on VOC concentrations in a building that had been subjected to water damage. While air samplings in a damp room at low RH (21–22 %) only revealed minor amounts of 2-ethylhexanol (3 μg/m³) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB, 8 μg/m³), measurements performed after a rapid increase of RH (to 58–75 %) revealed an increase in VOC concentrations which was 3-fold for 2-ethylhexanol and 2-fold for TXIB. Similar VOC emission patterns were found in laboratory analyses of moisture-affected and laboratory-contaminated building materials. This study demonstrates the importance of monitoring RH when sampling indoor air for VOCs in order to avoid misleading conclusions from the analytical results.
显示更多 [+] 显示较少 [-]Pharmacodynamic interaction of Spirulina platensis and deltamethrin in freshwater fish Nile tilapia, Oreochromis niloticus: impact on lipid peroxidation and oxidative stress
2015
Abdelkhalek, Nevien K. M. | Ghazy, Emad W. | Abdel-Daim, Mohamed M.
Spirulina platensis (SP) is one of the most commonly used dietary supplements in human and many animal species, including fish. Recently, it has gained more attention in fish not only for its growth-promoting and immunomodulatory effects but also for its antioxidant potential. The present study was conducted to investigate the protective role of two different dietary levels of SP on freshwater Nile tilapia; Oreochromis niloticus exposed to subacute deltamethrin (DLM) intoxication. Spirulina was supplemented at levels of 0.5 and 1 % in the diet along with DLM at a concentration of 1.46 μg/l for 28 days. Serum biochemical parameters, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein, albumin, cholesterol, urea, uric acid and creatinine, were estimated. In addition, the level of malondialdehyde (MDA) was analysed as a lipid peroxidation marker. Reduced glutathione (GSH) content and glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) activities were analysed as antioxidant biomarkers in liver, kidney and gills. The results revealed that DLM intoxication increased serum AST, ALT, ALP, cholesterol, urea, uric acid, creatinine and tissue MDA, while decreased serum total protein and albumin as well as tissue GSH level and GSH-Px, SOD and CAT activities. SP supplementation at the two tested levels enhanced all altered serum biochemical parameters as well as tissue lipid peroxidation and antioxidant biomarkers. Therefore, it could be concluded that SP administration could minimize DLM-induced toxic effects by its free radical scavenging and potent antioxidant activity.
显示更多 [+] 显示较少 [-]Brake wear particle emissions: a review
2015
Grigoratos, Theodoros | Martini, Giorgio
Traffic-related sources have been recognized as a significant contributor of particulate matter particularly within major cities. Exhaust and non-exhaust traffic-related sources are estimated to contribute almost equally to traffic-related PM₁₀emissions. Non-exhaust particles can be generated either from non-exhaust sources such as brake, tyre, clutch and road surface wear or already exist in the form of deposited material at the roadside and become resuspended due to traffic-induced turbulence. Among non-exhaust sources, brake wear can be a significant particulate matter (PM) contributor, particularly within areas with high traffic density and braking frequency. Studies mention that in urban environments, brake wear can contribute up to 55 % by mass to total non-exhaust traffic-related PM₁₀emissions and up to 21 % by mass to total traffic-related PM₁₀emissions, while in freeways, this contribution is lower due to lower braking frequency. As exhaust emissions control become stricter, relative contributions of non-exhaust sources—and therefore brake wear—to traffic-related emissions will become more significant and will raise discussions on possible regulatory needs. The aim of the present literature review study is to present the state-of-the-art of the different aspects regarding PM resulting from brake wear and provide all the necessary information in terms of importance, physicochemical characteristics, emission factors and possible health effects.
显示更多 [+] 显示较少 [-]A coordinated set of ecosystem research platforms open to international research in ecotoxicology, AnaEE-France
2015
Mougin, Christian | Azam, Didier | Caquet, Thierry | Cheviron, Nathalie | Dequiedt, Samuel | Le Galliard, Jean-François | Guillaume, Olivier | Houot, Sabine | Lacroix, Gerard | Lafolie, François | Maron, Pierre-Alain | Michniewicz, Radika | Pichot, Christian | Ranjard, Lionel | Roy, Jacques | Zeller, Bernd | Clobert, Jean | Chanzy, André
The infrastructure for Analysis and Experimentation on Ecosystems (AnaEE-France) is an integrated network of the major French experimental, analytical, and modeling platforms dedicated to the biological study of continental ecosystems (aquatic and terrestrial). This infrastructure aims at understanding and predicting ecosystem dynamics under global change. AnaEE-France comprises complementary nodes offering access to the best experimental facilities and associated biological resources and data: Ecotrons, seminatural experimental platforms to manipulate terrestrial and aquatic ecosystems, in natura sites equipped for large-scale and long-term experiments. AnaEE-France also provides shared instruments and analytical platforms dedicated to environmental (micro) biology. Finally, AnaEE-France provides users with data bases and modeling tools designed to represent ecosystem dynamics and to go further in coupling ecological, agronomical, and evolutionary approaches. In particular, AnaEE-France offers adequate services to tackle the new challenges of research in ecotoxicology, positioning its various types of platforms in an ecologically advanced ecotoxicology approach. AnaEE-France is a leading international infrastructure, and it is pioneering the construction of AnaEE (Europe) infrastructure in the field of ecosystem research. AnaEE-France infrastructure is already open to the international community of scientists in the field of continental ecotoxicology.
显示更多 [+] 显示较少 [-]Phenol degradation using the mixed material clay/Fe immobilized on glass slides
2015
Taketa, Lidiane Yumi | Ignachewski, Franciély | Villalba, Juan Carlo | Anaissi, Fauze Jacó | Fujiwara, Sérgio Toshio
The mixed material clay/Fe was prepared and immobilized on glass slides and calcined at 550 and 750 °C. The calcined material X-ray powder pattern (XRD) diffractograms indicate that there is no intercalation of iron compounds inside the lamella clay. The experimental design revealed that the most suitable phenol degradation conditions were obtained using the material calcined at 750 °C in a pH 7 and 140 mg/L of hydrogen peroxide solution. The material MMAFe750 showed excellent performance as a catalyst for Fenton-like reaction; in 125 min, 50 % of phenol was removed in the absence of leaching-supported iron. These results indicate that the reaction occurs by a heterogeneous process. Furthermore, the material showed no loss of catalytic activity after five degradation studies. It was noted that the adsorption of phenol in the synthesized materials does not occur and the mixed material is strongly adsorbed onto glass slides.
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