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Результаты 1401-1410 из 1,535
Identification and evaluation of air-pollution-tolerant plants around lignite-based thermal power station for greenbelt development
2012
Govindaraju, M. | Ganeshkumar, R. S. | Muthukumaran, V. R. | Visvanathan, P.
INTRODUCTION: Thermal power plants emit various gaseous and particulate pollutants into the atmosphere. It is well known that trees help to reduce air pollution. Development of a greenbelt with suitable plant species around the source of emission will mitigate the air pollution. Selection of suitable plant species for a greenbelt is very important. MATERIALS AND METHODS: Present study evaluates different plant species around Neyveli thermal power plant by calculating the Air Pollution Tolerance Index (APTI) which is based on their significant biochemical parameters. Also Anticipated Performance Index (API) was calculated for these plant species by combining APTI values with other socio-economic and biological parameters. DISCUSSION: Based on these indices, the most appropriate plant species were identified for the development of a greenbelt around the thermal power plant to mitigate air pollution. Among the 30 different plant species evaluated, Mangifere indica L. was identified as keystone species which is coming under the excellent category. CONCLUSION: Ambient air quality parameters were correlated with the biochemical characteristics of plant leaves and significant changes were observed in the plants biochemical characteristics due to the air pollution stress.
Показать больше [+] Меньше [-]Triclosan—the forgotten priority substance?
2012
von der Ohe, Peter Carsten | Schmitt-Jansen, Mechthild | Slobodnik, Jaroslav | Brack, Werner
INTRODUCTION: Triclosan (TCS) is a multi-purpose biocide. Its wide use in personal care products (PCPs) fosters its dispersal in the aquatic environment. Despite enhanced awareness of both scientists and the public in the last decade with regard to fate and effects, TCS received little attention regarding its prioritisation as a candidate river basin-specific pollutant or even priority substance, due to scarce monitoring data. METHODS: Applying a new prioritisation methodology, the potential risk of TCS was assessed based on a refined hazard assessment and occurrences at 802 monitoring sites in the Elbe River basin. RESULTS: The suggested acute-based predicted no-effect concentration (PNEC) of 4.7 ng/l for the standard test species Selenastrum capricornutum was in good agreement with effect concentrations in algal communities and was exceeded in the Elbe River basin at 75% of the sites (limit of quantification of 5 ng/l). The 95th percentile of the maximum environmental concentrations at each site exceeded the PNEC by a factor of 12, indicating potential hazards for algal communities. Among 500 potential river basin-specific pollutants which were recently prioritised, triclosan ranks on position 6 of the most problematic substances, based on the Elbe River data alone. CONCLUSION: Considering the worldwide application of PCPs containing triclosan, we expect that the TCS problem is not restricted to the Elbe River basin, even if monitoring data from other river basins are scarce. Thus, we suggest to include TCS into routine monitoring programmes and to consider it as an important candidate for prioritisation at the European scale.
Показать больше [+] Меньше [-]Quantitative structure-retention relationship for retention behavior of organic pollutants in textile wastewaters and landfill leachate in LC-APCI-MS
2012
Noorizadeh, Hadi | Farmany, Abbas
INTRODUCTION: A quantitative structure-retention relation (QSRR) study was conducted on the retention times of organic pollutants in textile wastewaters and landfill leachate which was obtained by liquid chromatography-reversed phase-atmospheric pressure chemical ionization-mass spectrometry. METHODS: The genetic algorithm was used as descriptor selection and model development method. Modeling of the relationship between selected molecular descriptors and retention time was achieved by linear (partial least square) and nonlinear (Levenberg-Marquardt artificial neural network, L-M ANN) methods. Linear and nonlinear models provide good results whereas more accurate results were obtained by the L-M ANN model. CONCLUSION: This is the first research on the QSRR of the organic pollutants in textile wastewaters and landfill leachate against the retention time.
Показать больше [+] Меньше [-]Biosorption of zinc and copper from aqueous solutions by two freshwater green microalgae Chlorella pyrenoidosa and Scenedesmus obliquus
2012
Zhou, Guang-Jie | Peng, Fu-Qiang | Zhang, Li-Juan | Ying, Guang-Guo
PURPOSE: The objective of this study was to determine the removal of zinc and copper by two freshwater green microalgae Chlorella pyrenoidosa and Scenedesmus obliquus and to investigate changes of algal ultrastructure and photosynthetic pigment. METHODS: Algal cells were exposed for 8 days to different initial zinc or copper concentrations. Heavy metal concentrations were detected by an atomic absorption spectrophotometer. Algal growth, ultrastructure, and photosynthetic pigment were analyzed by a microplate reader, transmission electron microscope, and spectrophotometer, respectively. RESULTS: Low zinc and copper concentrations induced increase in algal growth, whereas application of high zinc and copper concentrations suppressed the growth of both algae. High metal concentrations also decreased the photosynthetic pigments and destroyed algal cell ultrastructure. The zinc removal efficiency by both algae increased rapidly during the first day and thereafter remained nearly constant throughout the experiment. The copper removal efficiency by both algae increased slowly during the whole experimental periods. In all cultures, the quantity of both metals removed intracellularly was much lower than the adsorbed quantity on the cell surface. CONCLUSIONS: Both strains of the microalgae had proven effective in removing zinc and copper from aqueous solutions, with the highest removal efficiency being near 100%. In addition, C. pyrenoidosa appeared to be more efficient than S. obliquus for removing copper ions. On the contrary, S. obliquus appeared to be more efficient than C. pyrenoidosa for removing zinc ions.
Показать больше [+] Меньше [-]Ready biodegradability of trifluoromethylated phenothiazine drugs, structural elucidation of their aquatic transformation products, and identification of environmental risks studied by LC-MS n and QSAR
2012
Trautwein, Christoph | Kümmerer, Klaus
The environmental fate of transformation products from organic pollutants such as drugs has become a new research area of increasing interest over the last few years. Whereas in the past mainly parent compounds or their major human metabolites were studied, new questions have arisen what compounds could be formed during incomplete degradation in the aquatic environment and what effects the resulting transformation products might have on nature and mankind. Psychiatric drugs are among the most important prescription drugs worldwide, but so far only little data is provided upon their degradation behavior. This especially accounts for tricyclic antipsychotic drugs of the phenothiazine class. Therefore, the degradation of such drugs was investigated in this study. In this study the aerobic Closed Bottle test (The Organisation for Economic Co-operation and Development (OECD) 301D) was used to assess the ready biodegradability of three trifluoromethylated phenothiazine drugs: fluphenazine, triflupromazine, and trifluoperazine. As it is known from literature that phenothiazine drugs can easily form various photolytic transformation products under light exposure, photochemical transformation was also investigated. Since transformation products are usually not available commercially, the calculation of environmental parameters with the aid of quantitative structure activity relationship (QSAR) software was used for first evaluation of these compounds. According to the OECD test guideline, all trifluoromethylated phenothiazines had to be classified as not readily biodegradable. Chromatographic data revealed the formation of some transformation products. Comparing retention time and mass spectrometric data with the analytical results of the light exposure experiments, we found peaks with the same retention time and mass spectra. So these transformation products were not of bacterial, but photolytic, origin and are formed very quickly even under low light doses. A special chromatographic column and solvent gradient along with multiple stage mass spectrometric fragmentation experiments uncovered the presence of, in total, nine photolytic transformation products and allowed for their structural elucidation. Typical modifications of the molecules were sulfoxidation, exocyclic N-oxidation, and transformation of the trifluoromethyl to a carboxylic moiety. The obtained results of the QSAR calculations show that all transformation products are highly mobile in the aquatic environment and elimination through biotic or abiotic pathways cannot be expected. Transformation products of trifluoromethylated phenothiazine drugs have to be expected in the aquatic environment, yet nothing is known about their toxicological properties. Therefore, further risk assessment upon these drugs and their fate is strongly recommended.
Показать больше [+] Меньше [-]Thirty-year amendment of horse manure and chemical fertilizer on the availability of micronutrients at the aggregate scale in black soil
2012
Fan, Jianling | Ding, Weixin | Chen, Zengming | Ziadi, Noura
PURPOSE: This study evaluates manure and chemical fertilizer effects on micronutrient (Fe, Mn, Cu, and Zn) content and availability in crops. METHODS: Seven treatments were selected, including three conventional fertilization treatments (NP, horse manure (M), and NP plus M (NPM)), three corresponding double rate fertilization (N2P2, M2, and N2P2M2), and a CK. Soil samples were collected and separated into four aggregates by wet-sieving in September 2009. Corn samples were collected and analyzed simultaneously. RESULTS: Treatment N2P2 increased DTPA extractable Fe, Mn, and Cu in soil by 732%, 388%, and 42%, whereas M2 decreased the corresponding values by 26%, 22%, and 10%, respectively, compared to CK. DTPA extractable Zn in soil and Zn in corn grain were higher in the M and M2 treatments than in the other treatments, and DTPA Zn was significantly correlated with soil organic carbon (SOC) in large macroaggregate, microaggregate, and silt + clay fractions. The Mn concentrations in corn stalks and grain were significantly correlated with DTPA extractable Mn in bulk soil and microaggregates, and Zn in stalks were significantly correlated with DTPA Zn in bulk soil, microaggregates, and large macroaggregates. CONCLUSIONS: Long-term application of horse manure could increase soil Zn availability and uptake by corn, possibly due to its activation by SOC. In contrast, chemical fertilizer application increased DTPA extractable Fe, Mn, and Cu in soil by reducing soil pH. Our results also suggest that Mn uptake by corn originated mainly in microaggregates, whereas Zn in crops was primarily sourced from large macroaggregates and microaggregates.
Показать больше [+] Меньше [-]Occurrence of priority organic pollutants in Strymon river catchment, Greece: inland, transitional, and coastal waters
2012
Litskas, V. D. | Dosis, I. G. | Karamanlis, X. N. | Kamarianos, A. P.
Twenty-five sampling stations were selected in order to monitor persistent organic pollutants (polycyclic aromatic hydrocarbons (PAHs), organochlorine (OC) pesticides and total polychlorinated biphenyls (PCBs)) in surface water from Kerkini Lake, the Strymon River, its main tributaries and estuary in N. Aegean Sea during January to July, 2008, according to recent European Union (EU) guidelines. The data were divided among the high (January to April) and the low flow season (May to July). Generally, the values for organic pollutants were within the range reported worldwide for surface water. Elevated PAHs concentrations were observed compared with other places in Greece. Anthracene and benzo(a)pyrene exceeded maximum allowable concentration (MAC) of the relative EU guideline. Also, concentrations above MAC were observed for OCs, γ-HCH, and a-endosulfan. Despite the fact that it is banned since 1972, Aldrin was detected during the monitoring season (from limit of detection (LOD) to 15 ng L−1). Total PCB concentrations ranged from LOD to 162 ng L−1. In addition, the load of organic pollutants was estimated in April (high flow) and June (low flow) in selected sampling stations. According to this estimation, napthalene, anthracene, and fluoranthene (PAHs), total dichlorodiphenyltrichloroethane (DDT), aldrin, and total PCBs had the highest load. Taking into account the relative EU guidelines concerning the pollutants studied, the water quality in the Strymon River catchment could be characterized as poor, which can lead to negative impacts to its biota.
Показать больше [+] Меньше [-]Contribution of anthropogenic aerosols in direct radiative forcing and atmospheric heating rate over Delhi in the Indo-Gangetic Basin
2012
Srivastava, Atul K. | Singh, Sachchidanand | Tiwari, S. | Bisht, D. S.
INTRODUCTION: The present work is aimed to understand direct radiation effects due to aerosols over Delhi in the Indo-Gangetic Basin (IGB) region, using detailed chemical analysis of surface measured aerosols during the year 2007. METHODS: An optically equivalent aerosol model was formulated on the basis of measured aerosol chemical compositions along with the ambient meteorological parameters to derive radiatively important aerosol optical parameters. The derived aerosol parameters were then used to estimate the aerosol direct radiative forcing at the top of the atmosphere, surface, and in the atmosphere. RESULTS: The anthropogenic components measured at Delhi were found to be contributing ∼72% to the composite aerosol optical depth (AOD0.5 ∼0.84). The estimated mean surface and atmospheric forcing for composite aerosols over Delhi were found to be about −69, −85, and −78 W m−2 and about +78, +98, and +79 W m−2 during the winter, summer, and post-monsoon periods, respectively. The anthropogenic aerosols contribute ∼90%, 53%, and 84% to the total aerosol surface forcing and ∼93%, 54%, and 88% to the total aerosol atmospheric forcing during the above respective periods. The mean (±SD) surface and atmospheric forcing for composite aerosols was about −79 (±15) and +87 (±26) W m−2 over Delhi with respective anthropogenic contributions of ∼71% and 75% during the overall period of observation. CONCLUSIONS: Aerosol induced large surface cooling, which was relatively higher during summer as compared to the winter suggesting an increase in dust loading over the station. The total atmospheric heating rate at Delhi averaged during the observation was found to be 2.42 ± 0.72 K day−1, of which the anthropogenic fraction contributed as much as ∼73%.
Показать больше [+] Меньше [-]Glutathione, glutathione S-transferase, and glutathione conjugates, complementary markers of oxidative stress in aquatic biota
2012
Hellou, Jocelyne | Ross, Neil W. | Moon, T. W. (Thomas W.)
Contaminants are ubiquitous in the environment and their impacts are of increasing concern due to human population expansion and the generation of deleterious effects in aquatic species. Oxidative stress can result from the presence of persistent organic pollutants, metals, pesticides, toxins, pharmaceuticals, and nanomaterials, as well as changes in temperature or oxygen in water, the examined species, with differences in age, sex, or reproductive cycle of an individual. The antioxidant role of glutathione (GSH), accompanied by the formation of its disulfide dimer, GSSG, and metabolites in response to chemical stress, are highlighted in this review along with, to some extent, that of glutathione S-transferase (GST). The available literature concerning the use and analysis of these markers will be discussed, focusing on studies of aquatic organisms. The inclusion of GST within the suite of biomarkers used to assess the effects of xenobiotics is recommended to complement that of lipid peroxidation and mixed function oxygenation. Combining the analysis of GSH, GSSG, and conjugates would be beneficial in pinpointing the role of contaminants within the plethora of causes that could lead to the toxic effects of reactive oxygen species.
Показать больше [+] Меньше [-]Identification of volatiles from Pinus silvestris attractive for Monochamus galloprovincialis using a SPME-GC/MS platform
2012
Szmigielski, Rafal | Cieslak, Marek | Rudzinski, Krzysztof J. | Maciejewska, Barbara
INTRODUCTION: A myriad of volatile organic compounds (VOCs) released by terrestrial vegetation plays an important role in environmental sciences. A thorough chemical identification of these species at the molecular level is essential in various fields, ranging from atmospheric chemistry to ecology of forest ecosystems. In particular, the recognition of VOCs profiles in a context of plant–insect communication is a key issue for the development of forest protection tools. PURPOSE: This work was aimed at the development of a simple, robust and reliable method for the identification of volatiles emitted from plant materials, which can attract or deter pest insects. Specifically, volatiles emitted from the bark of Pinus sylvestris were studied, which might attract the black pine sawyer beetle Monochamus galloprovincialis—a serious pest of the tree and a vector of a parasitic nematode Bursaphelenchus xylophius. METHOD: The volatiles from bark samples were collected using a solid-phase micro-extraction technique, and subsequently analysed by gas-chromatography/mass-spectrometry (GC/MS). The characterisation of the volatile fraction was based on the comparison with data in mass spectral libraries, and in most cases, with the available authentic standards. The identified compounds were screened against the available entomological data to select insect attractors. RESULTS: The identified components included terpenes (α-pinene, ∆-3-carene, and para-cymenene), oxygenated terpenes (α-terpineol and verbenone), sesquiterpenes (α-longipinene, longifolene, E-β-farnesene, γ-cadinene and pentadecane), and diterpenes (manoyl oxide and (+)-pimaral). Of these, longifolene and (+)-pimaral are of particular interest as plausible attractors for the M. galloprovincialis beetle that might find application in the construction of insect bait traps.
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