خيارات البحث
النتائج 361 - 370 من 1,310
PBDD/F impurities in some commercial deca-BDE النص الكامل
2011
Ren, Man | Peng, Ping’an | Cai, Ying | Chen, Deyi | Zhou, Lin | Chen, Pei | Hu, Jianfang
The study presented the concentrations and distributions of polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans (PBDD/Fs) as impurities in some commercial decabromodiphenyl ether (DBDE) mixtures that were produced by several manufacturers. The total concentrations of 12 2,3,7,8-substituted tetra- to octa-BDD/F congeners were found to be in the range of 3.4–13.6 (mean 7.8)μg/g, averagely accounting for 99% of total PBDD/Fs. OBDF was the prevailing congener, followed by 1,2,3,4,6,7,8-HpBDF. In addition, OBDD and 1,2,3,4,7,8-HxBDF were also obviously detectable. The total concentrations of PBDD/Fs varied both between the manufacturers and between the lots. On the basis of the global demand for the commercial DBDE in 2001, the annual potential emissions of PBDD/Fs were calculated coarsely to be 0.43 (range: 0.21–0.78)tons. The major dioxin congeners, OBDF and 1,2,3,4,6,7,8-HpBDF, presenting in DBDE, were estimated to be formed from BDE-209, BDE-206, and/or BDE-207 via an intra-molecular elimination of Br₂/HBr.
اظهر المزيد [+] اقل [-]Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean النص الكامل
2011
Jaffal, A. | Givaudan, N. | Betoulle, S. | Terreau, A. | Paris-Palacios, S. | Biagianti-Risbourg, S. | Beall, E. | Roche, H.
Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean النص الكامل
2011
Jaffal, A. | Givaudan, N. | Betoulle, S. | Terreau, A. | Paris-Palacios, S. | Biagianti-Risbourg, S. | Beall, E. | Roche, H.
The Subantarctic Kerguelen Islands (49°S, 70°E) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358ngg⁻¹ lipid, and dioxin-like PCB was 19 and 69ngg⁻¹ lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the ‘river’ morphotype of brook trout showed the highest PCB levels.
اظهر المزيد [+] اقل [-]Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean النص الكامل
2011
Jaffal, Ali | Givaudan, Nicolas | Betoulle, Stéphane | Terreau, Alexandre | Paris-Palacios, Séverine | Biagianti-Risbourg, S. | Beall, Edward | Roche, H. | UNITE DE RECHERCHE VIGNES ET VINS DE CHAMPAGNE - STRESS ET ENVIRONNEMENT - EA2069 (URVV - SE) ; Université de Reims Champagne-Ardenne (URCA) | Ecologie Systématique et Evolution (ESE) ; Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS) | Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO) ; Université de Rennes (UR)-Institut Ecologie et Environnement (INEE) ; Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR) ; Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS) | L'Institut polaire français Paul-Emile Victor (IPEV) ; Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.) | Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP) ; Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA) | Programme IPEV 409 IMMUNOTOXKER
International audience | The Subantarctic Kerguelen Islands (49°S, 70°E) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g-1 lipid, and dioxin-like PCB was 19 and 69 ng g-1 lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels.
اظهر المزيد [+] اقل [-]Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean النص الكامل
2011
Jaffal, Ali | Givaudan, Nicolas | Betoulle, Stéphane | Terreau, Alexandre | Paris-Palacios, Séverine | Biagianti-Risbourg, S. | Beall, Edward | Roche, H. | UNITE DE RECHERCHE VIGNES ET VINS DE CHAMPAGNE - STRESS ET ENVIRONNEMENT - EA2069 (URVV - SE) ; Université de Reims Champagne-Ardenne (URCA) | Ecologie Systématique et Evolution (ESE) ; Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS) | Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO) ; Université de Rennes (UR)-Institut Ecologie et Environnement - CNRS Ecologie et Environnement (INEE-CNRS) ; Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) | L'Institut polaire français Paul-Emile Victor (IPEV) ; Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.) | Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP) ; Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA) | Programme IPEV 409 IMMUNOTOXKER
International audience | The Subantarctic Kerguelen Islands (49°S, 70°E) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g-1 lipid, and dioxin-like PCB was 19 and 69 ng g-1 lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels.
اظهر المزيد [+] اقل [-]Bioindication of atmospheric trace metals – With special references to megacities النص الكامل
2011
Markert, Bernd | Wuenschmann, Simone | Fraenzle, Stefan | Graciana Figueiredo, Ana Maria | Ribeiro, Andreza P. | Wang, Meie
After considering the particular problems of atmospheric pollution in megacities, i.e. agglomerations larger than 5 mio. inhabitants, with urbanization of World’s population going on steadily, possibilities of active biomonitoring by means of green plants are discussed. Based on specific definitions of active and passive bioindication the chances of monitoring heavy metals in Sao Paulo megacity were demonstrated (first results published before). This is to show that there is need for increased use of bioindication to tackle the particular problems of megacities concerning environmental “health”, the data to be processed according to the Multi-Markered-Bioindication-Concept (MMBC). Comparison to other work shows this approach to be reasonable.
اظهر المزيد [+] اقل [-]A vegetation modeling concept for Building and Environmental Aerodynamics wind tunnel tests and its application in pollutant dispersion studies النص الكامل
2011
Gromke, Christof
A new vegetation modeling concept for Building and Environmental Aerodynamics wind tunnel investigations was developed. The modeling concept is based on fluid dynamical similarity aspects and allows the small-scale modeling of various kinds of vegetation, e.g. field crops, shrubs, hedges, single trees and forest stands. The applicability of the modeling concept was validated in wind tunnel pollutant dispersion studies. Avenue trees in urban street canyons were modeled and their implications on traffic pollutant dispersion were investigated. The dispersion experiments proved the modeling concept to be practicable for wind tunnel studies and suggested to provide reliable concentration results. Unfavorable effects of trees on pollutant dispersion and natural ventilation in street canyons were revealed. Increased traffic pollutant concentrations were found in comparison to the tree-free reference case.
اظهر المزيد [+] اقل [-]Organic persistent toxic substances in soils, waters and sediments along an altitudinal gradient at Mt. Sagarmatha, Himalayas, Nepal النص الكامل
2011
Guzzella, Licia | Poma, Giulia | De Paolis, Adolfo | Roscioli, Claudio | Viviano, Gaetano
Persistent Organic Pollutants (POPs) and Polycyclic Aromatic Hydrocarbons (PAHs) are important classes of compounds of serious environmental concern. These compounds were measured in waters, sediments and soils from several high altitude sites in the Sagarmatha National Park (Nepal) and included in the Himalayan ridge. In water samples, low-level substituted PCBs and PBDEs, along with more volatile PAHs, were the most common contaminants. In sediment and soil samples, the PCB profile was mainly composed of medium-level chlorinated congeners and significantly correlated with altitude. The PAH profile for water and soil samples showed the main contribution of pyrogenic PAHs due to emissions of solid combustion, whereas the profile for sediments indicated the main contribution of pyrogenic PAHs from gasoline emissions. The PAH levels measured in Himalayan samples must be considered as low to medium contaminated, whereas the regarded Himalayan stations can be considered undisturbed remote areas concerning PCB, PBDE and OC compounds.
اظهر المزيد [+] اقل [-]Carbon isotope signature of dissolved inorganic carbon (DIC) in precipitation and atmospheric CO₂ النص الكامل
2011
Górka, Maciej | Sauer, Peter E. | Lewicka-Szczebak, Dominika | Jędrysek, Mariusz Orion
This paper describes results of chemical and isotopic analysis of inorganic carbon species in the atmosphere and precipitation for the calendar year 2008 in Wrocław (SW Poland). Atmospheric air samples (collected weekly) and rainwater samples (collected after rain episodes) were analysed for CO₂ and dissolved inorganic carbon (DIC) concentrations and for δ¹³C composition. The values obtained varied in the ranges: atmospheric CO₂: 337–448ppm; δ¹³CCO₂ from −14.4 to −8.4‰; DIC in precipitation: 0.6–5.5mgdm⁻³; δ¹³CDIC from −22.2 to +0.2‰. No statistical correlation was observed between the concentration and δ¹³C value of atmospheric CO₂ and DIC in precipitation. These observations contradict the commonly held assumption that atmospheric CO₂ controls the DIC in precipitation. We infer that DIC is generated in ambient air temperatures, but from other sources than the measured atmospheric CO₂. The calculated isotopic composition of a hypothetical CO₂ source for DIC forming ranges from −31.4 to −11.0‰, showing significant seasonal variations accordingly to changing anthropogenic impact and atmospheric mixing processes.
اظهر المزيد [+] اقل [-]Occurrence of perfluorooctanoate and perfluorooctanesulfonate in the Korean water system: Implication to water intake exposure النص الكامل
2011
Kim, Seung-Kyu | Kho, Young Lim | Shoeib, Mahiba | Kim, Kyoung-Soo | Kim, Kyung-Ryul | Park, Jong-Eun | Shin, Yong-Seung
Perfluorinated compounds (PFCs) measured in surface running waters indicated the existence of different emission sources in eight main city basins. The tap water reflected the contamination pattern and levels in their corresponding source water basins. The daily intakes through tap water consumption ranged from <0.01 to 0.73 ng kg⁻¹ d⁻¹ for perfluorooctanoate (PFOA) and <0.01 to 0.08 ng kg⁻¹ d⁻¹ for perfluorooctanesulfonate (PFOS). Tap water intake-derived exposure accounted for 8.6%–101% (for PFOA) and while <10% (for PFOS) of total daily exposure, which was estimated from Korean serum concentrations using a pharmacokinetic model. Our findings indicate that tap water intake could be an important contributor to PFOA exposure in Korean populations; accordingly, additional efforts are necessary to improve the removal efficiency of perfluorinated compounds (PFCs) in the water purification process. However, more fundamentally the aim would be to reduce the discharge of PFCs from potential sources within the basin.
اظهر المزيد [+] اقل [-]Polycyclic aromatic hydrocarbons in lake sediments from the High Tatras النص الكامل
2011
van Drooge, Barend L. | López, Jordi | Fernández, Pilar | Grimalt, Joan O. | Stuchlík, Evzen
European alpine lake systems are used as indicators of air quality over the continent. Preliminary data showed high polycyclic aromatic hydrocarbons (PAH) loads in the High Tatras (Eastern Europe) in comparison to other mountain regions. Here, insight on the spatial distribution of PAH is provided from analysis of top-core sediments of 27 alpine lakes distributed along the High Tatras. Top-core sediment concentrations were higher than those in deep-cores, and they were higher than those observed in other European high mountain regions. The PAH profiles were uniform and comparable to those observed in aerosols and snow, indicating that atmospheric deposition was the predominant PAH input pathway to the lakes. Good agreement between estimated atmospheric deposition and sedimentation fluxes was observed. However, in several lakes in the western range higher sediment fluxes may correspond to higher PAH depositions levels. The higher concentrations may also reflect inputs from potential emission source areas.
اظهر المزيد [+] اقل [-]Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors النص الكامل
2011
Marek, Michal V. | Janouš, Dalibor | Taufarová, Klára | Havránková, Kateřina | Pavelka, Marian | Kaplan, Věroslav | Marková, Irena
By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands.
اظهر المزيد [+] اقل [-]The tree BVOC index النص الكامل
2011
Simpson, J.R. | McPherson, E.G.
Urban trees can produce a number of benefits, among them improved air quality. Biogenic volatile organic compounds (BVOCs) emitted by some species are ozone precursors. Modifying future tree planting to favor lower-emitting species can reduce these emissions and aid air management districts in meeting federally mandated emissions reductions for these compounds. Changes in BVOC emissions are calculated as the result of transitioning to a lower-emitting species mix in future planting. A simplified method for calculating the emissions reduction and a Tree BVOC index based on the calculated reduction is described. An example illustrates the use of the index as a tool for implementation and monitoring of a tree program designed to reduce BVOC emissions as a control measure being developed as part of the State Implementation Plan (SIP) for the Sacramento Federal Nonattainment Area.
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