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2007-4-27 EST最新文章和摘要
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Semi Volatile Organic Compounds in Ambient PM2.5. Seasonal Trends and Daily Resolved Source Contributions Jürgen Schnelle-Kreis,* Martin Sklorz, Jürgen Orasche, Matthias Stölzel, Annette Peters, and Ralf Zimmermann Department of Chemistry, Bavarian Institute of Applied Environmental Research and Technology, BIfA GmbH, Am Mittleren Moos 46, 86167 Augsburg, Germany, Institute of Ecological Chemistry, GSF-National Research Centre for Environment and Health, Ingolstädter Landstrasse 1, 86573 Neuherberg, Germany, Institute of Epidemiology, GSF-National Research Centre for Environment and Health, Ingolstädter Landstrasse 1, 86573 Neuherberg, Germany, and Department of Analytical Chemistry, University of Augsburg, Universitätsstrasse 1, 86159 Augsburg, Germany Received for review March 21, 2006 Revised manuscript received January 5, 2007 Accepted March 28, 2007 Abstract: Concentrations of ambient semivolatile organic compounds (SVOC) in the PM2.5 fraction of Augsburg, Germany, have been monitored on a daily basis from January 2003 through December 2004. Samples were taken in a large garden in the city center. Quantitative analysis of n-alkanes, alkanones, alkanoic acid methylesters, long chain linear alkyl benzenes and toluenes, hopanes, polycyclic aromatic hydrocarbons (PAH) and oxidized PAH, and some abietan type diterpenes was done. All compounds showed distinct seasonal variations in concentration. Most compounds showed highest concentrations during the cold seasons, but some n-alkanones and 6,10,14-trimethylpentadecanone showed maximum concentration during summer. Changes in patterns between and within compound classes were obvious, e.g., the hopane pattern exhibited a strong seasonal variation. The main source related contributions to changes observed were discussed. Using positive matrix factorization (PMF) for the statistical investigation of the data set, five factors have been separated. These factors are dominated by the pattern of single sources or groups of similar sources: factor 1, lubricating oil; factor 2, emissions of unburned diesel and heating oil consumption; factor 3, wood combustion; factor 4, brown coal combustion; and factor 5, biogenic emissions and transport components. Like the SVOC, the factors showed strong seasonality with highest values in winter for factors 1-4 and in summer for factor 5. -------------------------------------------------------------------------------- Photochemical Loss of Nitric Acid on Organic Films: a Possible Recycling Mechanism for NOx Susannah R. Handley, Daniel Clifford, and D. J. Donaldson* Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6, and Department of Physical and Environmental Sciences, University of Toronto at Scarborough, Toronto, Ontario, Canada Received for review August 25, 2006 Revised manuscript received January 5, 2007 Accepted March 21, 2007 Abstract: The films coating urban impervious surfaces have been found to be comprised of about 7% inorganic nitrate and ~10% organic compounds (by mass). A simple steady-state analysis of the lifetime of the nitrate in the film suggests the existence of a loss process(es) in addition to washout by rainfall. We show here that gas-phase nitric acid can be taken up in organic films and lower the film pH. Photolysis of nitrated films using actinic illumination causes loss both of protons and of nitrate anion. We argue that this is possibly due to a combination of direct and indirect (photosensitized) photochemistry involving nitrate ions, yielding gas-phase HONO and/or NO2. -------------------------------------------------------------------------------- Residues of Persistent Organochlorine Contaminants in Southern Elephant Seals (Mirounga leonina) from Elephant Island, Antarctica Kleber C. Miranda-Filho, Tracy L. Metcalfe, Chris D. Metcalfe, Ricardo B. Robaldo, Mônica M. C. Muelbert, Elton P. Colares, Pablo E. Martinez, and Adalto Bianchini* Programa de Pós-Graduação em Oceanografia Biológica, Fundação Universidade Federal do Rio Grande, Av. Itlia km 8, 96 201-900, Rio Grande-RS, Brazil, Water Quality Centre, Trent University, Peterborough, ON, Canada, and Departamento de Ciências Fisiológicas, Fundação Universidade Federal do Rio Grande, Av. Itlia km 8, 96 201-900, Rio Grande-RS, Brazil Received for review September 5, 2006 Revised manuscript received March 15, 2007 Accepted March 16, 2007 Abstract: Contamination of blubber tissues by organochlorine pesticides (OC) and PCBs was assessed in female and male pups and juveniles, as well as in adult females and subdominant adult males of the Southern elephant seal, Mirounga leonina, from Elephant Island in the Antarctic Peninsula. All residues of persistent organochlorine contaminants analyzed were found in blubber samples, except for -HCH, endosulfan II, endrin, heptachlor, and aldrin. The relative concentrations of the analytes detected were DDT > PCB > chlordane > mirex > dieldrin > HCB> endosulfan > methoxychlor > HCHs > other OC pesticides. OC and PCBs concentrations were 1 or 2 orders of magnitude lower than those found in pinnipeds from northern hemisphere. The ratio DDT/PCB was higher in southern elephant seals. The relative importance of some OC residues indicates that pesticides used either currently or in the recent past in countries in the southern hemisphere are the sources of contamination in the Antarctic region. Data showed that concentrations of contaminants generally increased from pups < juveniles < adults and suggested that pups accumulated contaminants through transfer from the mother seals via transplacental and lactational routes. -------------------------------------------------------------------------------- Extending the Rayleigh Equation to Allow Competing Isotope Fractionating Pathways to Improve Quantification of Biodegradation Boris M. Van Breukelen* Department of Hydrology and Geo-Environmental Sciences, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands Received for review December 1, 2006 Revised manuscript received February 25, 2007 Accepted March 19, 2007 Abstract: The Rayleigh equation relates the change in isotope ratio of an element in a substrate to the extent of substrate consumption via a single kinetic isotopic fractionation factor (). Substrate consumption is, however, commonly distributed over several metabolic pathways each potentially having a different . Therefore, extended Rayleigh-type equations were derived to account for multiple competing degradation pathways. The value of as expressed in the environment appears a function of the values and rate constants of the various involved degradation pathways. Remarkably, the environmental or apparent value changes and shows non-Rayleigh behavior over a large and relevant concentration interval if Monod kinetics applies and the half-saturation constants of the competing pathways differ. Derived equations were applied to previously published data and enabled (i) quantification of the share that two competing degradation pathways had on aerobic 1,2-dichloroethane (1,2-DCA) biodegradation in laboratory batch experiments and (ii) calculation of the extent of methyl tert-butyl ether (MTBE) biodegradation shared over aerobic and anaerobic degradation at a field site by means of an improved solution to two-dimensional (carbon and hydrogen) compound-specific isotope analysis (CSIA). -------------------------------------------------------------------------------- Environ. Sci. Technol., ASAP Article --1, 10.1021/es078004s S0013-936X(07)08004-2 Web Release Date: April 27, 2007 Copyright © 2007 American Chemical Society Jane Bare,* Thomas Gloria, and Gregory Norris: Development of the Method and U.S. Normalization Database for Life Cycle Impact Assessment and Sustainability Metrics Environ. Sci. Technol., ASAP Article --1, 10.1021/es070460t S0013-936X(07)00460-9 Web Release Date: April 27, 2007 Copyright © 2007 American Chemical Society Susan D. Shaw,* Diane Brenner, Michelle L. Berger, David O. Carpenter, Chia-Swee Hong, and Karunthachalam Kannan: PCBs, PCDD/Fs, and Organochlorine Pesticides in Farmed Atlantic Salmon from Maine, Eastern Canada, and N Rate Coefficients for the OH + Pinonaldehyde (C10H16O2) Reaction between 297 and 374 K Maxine E. Davis, Ranajit K. Talukdar, Gregory Notte, G. Barney Ellison, and James. B. Burkholder* Earth System Research Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, Colorado 80305-3328, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215 Received for review January 8, 2007 Revised manuscript received March 21, 2007 Accepted March 22, 2007 Abstract: The rate coefficient for the reaction of OH with pinonaldehyde (C10H16O2, 3-acetyl-2,2-dimethyl-cyclobutyl-ethanal), a product of the atmospheric oxidation of -pinene, was measured under pseudo-first-order conditions in OH at temperatures between 297 and 374 K at 55 and 96 Torr (He). Laser induced fluorescence (LIF) was used to monitor OH in the presence of pinonaldehyde following its production by 248 nm pulsed laser photolysis of H2O2. The reaction exhibits a negative temperature dependence with an Arrhenius expression of k1(T) = (4.5 ± 1.3) × 10-12 exp((600 ± 100)/T) cm3 molecule-1 s-1; k1(297 K) = (3.46 ± 0.4) × 10-11 cm3 molecule-1 s-1. There was no observed dependence of the rate coefficient on pressure. Our results are compared with previous relative rate determinations of k1 near 297 K and the discrepancies are discussed. The state of knowledge for the atmospheric processing of pinonaldehyde is reviewed, and its role as a marker for -pinene (monoterpene) chemistry in the atmosphere is discussed. -------------------------------------------------------------------------------- |
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