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The Sources of Carbon and Nitrogen in Mountain Lakes and the Role of Human Activity in Their Modification Determined by Tracking Stable Isotope Composition Texto completo
2013
Gąsiorowski, Michał | Sienkiewicz, Elwira
We studied the isotopic composition of organic matter in the sediments of eight mountain lakes located in the Tatra Mountains (Western Carpathians, Poland). The sediments of the lakes were fine and course detritus gyttja, mud, and sand. The total organic carbon content varied from 0.5 to 53 %. The C/N ratio indicated that in-lake primary production is the major source of the organic matter in the lakes located above the treeline, whereas terrestrial plant fragments are the major organic compounds in the sediments of dystrophic forest lakes. We also found that a clear trend of isotopic curves toward lower values of δ ¹³C and δ ¹⁵N (both ~3 ‰) began in the 1960s. This trend is a sign of the deposition of greater amounts of NO ₓ from the combustion of fossil fuels, mainly by vehicle engines. The combustion of fossil fuels in electric plants and other factories had a smaller influence on the isotopic composition. This trend has been weaker since the 1990s. Animal and human wastes from pastures and tourism had a surprisingly minor effect on lake environments. These data are contrary to previous data regarding lake biota and suggest the high sensitivity of living organisms to organic pollution.
Mostrar más [+] Menos [-]Minor Losses During Air Flow into Granular Porous Media Texto completo
2013
Poulsen, Tjalfe G. | Minelgaite, Greta | Bentzen, Thomas R. | Andreasen, Rune R.
Pressure gradients during uniform fluid flow in porous media are traditionally assumed to be linear. Thus, pressure loss across a sample of porous medium is assumed directly proportional to the thickness of the sample. In this study, measurements of pressure gradients inside coarse granular (2-18 mm particle size) porous media during steady gas flow were carried out. The results showed that pressure variation with distance in the porous media was nonlinear near the inlet (where pressure gradients were higher) but became linear at greater distances (with a lower gradient). This indicates that the pressure loss in porous media consists of two components: (1) a linear pressure gradient and (2) an initial pressure loss near the inlet. This initial pressure loss is also known from hydraulics in tubes as a minor loss and is associated with abrupt changes in the flow field such as narrowings and bends. The results further indicated that the minor loss depends on the particle size and particle size distribution in a manner similar to that of the linear pressure gradient. There is, thus, a close relation between these two components. In porous media, the minor loss is not instantaneous at the inlet point but happens over some distance starting upstream from the inlet and ending some distance downstream. © 2013 Springer Science+Business Media Dordrecht.
Mostrar más [+] Menos [-]Rice Husk: Raw Material in the Catalyst Preparation for Advanced Oxidative Processes Applied in the Industrial Effluent Treatment and from Acid Drainage of a Mine Texto completo
2013
Lattuada, R. M. | Radtke, C. | Peralba, M. C. R. | Dos Santos, J. H. Z.
Application of an agricultural residue (rice husk, RH) as a raw material for catalyst support for advanced oxidative processes (AOPs) was evaluated. The supported catalyst was produced by the calcination of TiCl₄ impregnated in RH, thereby providing a composite TiO₂/Si-C, which was characterized by elemental analysis (CHN), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX), X-ray photoelectron spectroscopy (XPS), UV/VIS diffuse reflectance spectroscopic (DRS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), atomic force microscopy (AFM), SEM, and nitrogen adsorption–desorption isotherms (BET and BJH). Catalytic photodecomposition of methylene blue (MB), naphthalene, phenol, and abamectin and acid drainage of a mine by a titania-based catalyst composite were investigated. For comparative purposes, a commercial photocatalyst (TiO₂) was also employed. Photocatalytic degradation of MB, phenol, naphthalene, abamectin, and from coal mining effluent ranged from 8 to 93 % of the initial concentration. Performances of both catalysts were comparable. Additionally, in these evaluated systems, the toxicity of the effluent decreased after photocatalysis, either for Daphnia magna or for Scenedesmus subspicatus (employed as bioindicators).
Mostrar más [+] Menos [-]Reductions of PM₂.₅ Air Concentrations and Possible Effects on Premature Mortality in Japan Texto completo
2013
Nawahda, Amin
The current study estimates premature mortality caused by long-term exposure to elevated concentrations of PM₂.₅ (particulate matter with aerodynamic diameter equal to or less than 2.5 μm) in Japan from 2006 to 2009. The premature mortality is calculated based on a relative risk of 1.04 (95 % CI, 1.01–1.08) per 10 μg m⁻³ increase above the annual mean limit of 10 μg m⁻³ taken from the World Health Organization Air Quality Guidelines. The spatiotemporal variations of PM₂.₅ are estimated based on the measurements of suspended particulate matter (SPM) (with aerodynamic diameter approximately less than 7.0 μm) at 1,843 monitors. The improvements of air quality in Japan by reducing the emissions of SPM from 2006 to 2009 could save 3,602 lives based on a reduction target of 10 μg m⁻³ annual mean concentration. This finding could be a tangible benefit gained by reducing the emissions of particulate matter in Japan.
Mostrar más [+] Menos [-]Relative Contribution of Endocrine-disrupting Chemicals to the Estrogenic Potency of Marine Sediments of Osaka Bay, Japan Texto completo
2013
Koyama, Jiro | Kitoh, Asami | Nakai, Makoto | Kohno, Kumiko | Tanaka, Hiroyuki | Uno, Seiichi
Although concentrations of endocrine-disrupting chemicals (EDCs) in seawaters of Japan are relatively low, vitellogenin and ovotestis inductions are still being observed in some males of mullet and flounder collected in coastal areas. These fish species are benthic and could be affected by EDCs in marine sediments. Therefore, the concentrations of EDCs in marine sediments of Osaka Bay were determined by LC-MS/MS. In addition, the estrogen receptor binding potencies as estrogenic potencies of these sediments were assessed by the medaka estrogen receptor-α binding assay. Results show that estrogenic potencies were higher in sediments of the inner part of the bay especially at station 13 (off Sakai City) where quite strong estrogenic potency was detected. Through calculation of total E2 equivalent concentration (EEQ) in sediments, it was established that approximately 50 % of estrogenic potency was due to nonylphenol (NP), estrone and 17β-estradiol, suggesting that these compounds play important roles as endocrine disruptors in coastal environments of Osaka Bay.
Mostrar más [+] Menos [-]Estimating Aerosol Optical Depth Over the Broader Greek Area from MODIS Satellite Texto completo
2013
Athanassiou, G. | Hatzianastassiou, N. | Gkikas, A. | Papadimas, C. D.
A first-to-date comprehensive climatological aspect of the regime of aerosol loading over the entire broader Greek region (19 E-30 E and 34 N-43 N) is obtained using pixel-level (50 km × 50 km) monthly aerosol optical depth (AOD) products derived from raw Level-2 (10 km × 10 km) MODIS-Terra AOD data at 550 nm. The AOD climatology (for the 8-year period from March 2000 to February 2008) indicates that the study region is significantly loaded by aerosols (mean regional AOD equal to 0.196 ± 0.030 on an annual basis, with values ranging from 0.126 up to 0.382 at pixel level). It is also found that our high-resolution AOD data can reveal spatial patterns that are not evident in studies based on lower resolution data. There is a distinct longitudinal gradient of AODs, with higher values in the eastern than western part of the Greek peninsula. There is also a strong latitudinal gradient with decreasing values from south to north attributed to the presence of the Sahara Desert in northern Africa. The annual AOD cycle presents double maximum values, in spring and summer, and minimum ones in winter. There is also a remarkable year-by-year variability of AOD levels, especially as to their maxima, influenced by varying transport of desert dust, from the south, or biomass burning aerosols, from the north, to the region under prevailing favorable synoptic conditions. In this work, the processing, consisting in averaging over space and time, is done applying/testing five different criteria varying in their flexibility/severity in both spatial and temporal data availability. The criteria selection affects the magnitude of computed regional mean AOD value modifying it by up to 19 %, although the patterns of geographical distribution of AOD and its intra-annual variability do not change drastically. © 2013 Springer Science+Business Media Dordrecht.
Mostrar más [+] Menos [-]Enhanced Transport and Transformation of Zerovalent Nanoiron in Clay Using Direct Electric Current Texto completo
2013
Gomes, Helena I. | Dias-Ferreira, Celia | Ribeiro, Alexandra B. | Pamukcu, Sibel
One of the major obstacles to zerovalent iron nanoparticles (nZVI) application in soil and groundwater remediation is the limited transport, especially in low-permeability soils. In this study, direct current (constant potential of 5.0 V) was used to enhance polymer-coated nZVI mobility in different porous media, including a bed of glass beads and kaolin clay. The tests were conducted using a modified electrophoretic cell and with nZVI concentrations typical of field applications (4 g L-1). Experimental results indicate that the use of direct current can enhance the transport of the polymer-modified nanoparticles when compared with natural diffusion in low permeability or surface neutral porous medium. The applied electric field appeared to enhance the oxidation-reduction potential, creating a synergistic effect of nZVI usage with electrokinetics. Aggregation of the nanoparticles, observed near the injection point, remained unresolved. © 2013 Springer Science+Business Media Dordrecht.
Mostrar más [+] Menos [-]Bioaugmentation with Petroleum-Degrading Consortia Has a Selective Growth-Promoting Impact on Crop Plants Germinated in Diesel Oil-Contaminated Soil Texto completo
2013
Graj, Weronika | Lisiecki, Piotr | Szulc, Alicja | Chrzanowski, Łukasz | Wojtera-Kwiczor, Joanna
Rhizoremediation is a complex type of green clean-up technology that involves both plants and the rhizosphere-associated microorganisms to decompose hazardous compounds. The success of the strategy strongly depends on plant tolerance towards the pollutant, as well as plant's interactions with the rhizospheric microbes. The microorganisms may be stimulated by the secreted root exudates, which results in an increased breakdown of contaminants in the rhizosphere. The main goal of this study was to establish a potential rhizoremediation combination for a diesel-polluted site. Inoculation of plant roots or seeds with indigenous rhizospheric populations is a common approach in the rhizoremediation. However, we introduced hydrocarbon-degrading consortia (M10, R3, and K52) that were previously isolated from crude oil-contaminated soil instead of indigenous microbes. Bioaugmentation with these petroleum degraders was applied to screen four high biomass crop species (Indian mustard, alfalfa, high erucic acid rapeseed, HEAR, and low erucic acid rapeseed, LEAR) for their tolerance towards diesel oil. At no pollution, a promoting effect of M10 bacteria could be observed on germination and root elongation of all plant species. Moreover, M10 consortiums increased the germination index at 6,000 mg diesel oil per kilogram dry soil in the case of Indian mustard, alfalfa, and HEAR. The latter species was found to increment its dry weight upon bioaugmentation with M10 bacteria and all diesel oil treatments (6,000 and 24,000 mg diesel oil per kilogram dry soil). The initial results indicate HEAR and the M10 bacterial consortium as a promising plant-microbe tandem for a long-term rhizoremediation process. © 2013 The Author(s).
Mostrar más [+] Menos [-]Synthesis of Amino-Substituted p-tert-Butylcalix[4]arene for the Removal of Chicago Sky Blue and Tropaeolin 000 Azo Dyes from Aqueous Environment Texto completo
2013
Kamboh, Muhammad Afzal | Akoz, Enise | Memon, Shahabuddin | Yılmaz, Mustafa
In this study, we have reported the synthesis of new amino-substituted p-tert-butylcalix[4]arene (3) and its application for the removal of two carcinogenic azo dyes, i.e., Chicago Sky Blue (CSB) and Tropaeolin 000 (TP) from aqueous environment. The newly synthesized calix–ligand 3 is characterized by FT-IR and ¹H NMR spectroscopy as well as elemental analysis. The extraction efficiency of newly calix–ligand 3 for CSB and TP dyes from aqueous media was evaluated through liquid–liquid extraction experiments. The newly synthesized calix–ligand 3 showed outstanding extraction percentage and maximum percent extraction, i.e., 97 and 96 % of CSB and TP dyes was achieved at pH 9, respectively. During the extraction process, effect of various parameters was monitored and found that extraction is highly dependent on pH and salinity. Moreover, cyclic structure, cavity size, functional groups of the calixarene derivative, hydrophobicity, and the ionic property of guest molecules also affect the extraction efficiency. The comparative data prop up calix–ligand 3 as an effective extractant for both CSB and TP dyes.
Mostrar más [+] Menos [-]Studies on the Persistence of a Commercial Formulation of Chlorpyrifos on an Agricultural Soil from Provincia de Buenos Aires, República Argentina Texto completo
2013
Álvarez, Melina | du Mortier, Cecile | Sokolic, Tea | Cirelli, Alicia Fernández
Chlorpyrifos (O, O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) is a broad-spectrum organophosphate insecticide and acaricide, widely used in our country. Nowadays, it is the principal insecticide in the market employed for agricultural purposes. A number of studies tending to study the affinity of different pesticides with soil have been performed, but only a few refer to chlorpyrifos. Because of its intensive use, a wide range of terrestrial ecosystems may be contaminated with chlorpyrifos, and there is a need to evaluate its environmental behavior and effects. The aim of our work is to study the interaction and persistence of a commercial formulation of chlorpyrifos on an agricultural soil from Provincia de Buenos Aires, Argentina. In this case, recovery percentages increased with the increase of initial concentration of the pesticide until a concentration of about 25 ppm is reached, and then a decrease was observed. The half-time life was not affected by an increase in chlorpyrifos concentration.
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