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Environmental Science & Technology

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https://www.readbyqxmd.com/read/28644613/impact-of-thermal-decomposition-on-thermal-desorption-instruments-advantage-of-thermogram-analysis-for-quantifying-volatility-distributions-of-organic-species
#1
Harald Stark, Reddy L N Yatavelli, Samantha L Thompson, Hyungu Kang, Jordan Edward Krechmer, Joel R Kimmel, Brett B Palm, Weiwei Hu, Patrick L Hayes, Douglas A Day, Pedro Campuzano-Jost, Manjula R Canagaratna, John T Jayne, Douglas R Worsnop, Jose L Jimenez
We present results from a high-resolution chemical ionization time-of-flight mass spectrometer (HRToF-CIMS), operated with two different thermal desorption inlets, designed to characterize the gas and aerosol composition. Data from two field campaigns at forested sites are shown. Particle volatility distributions are estimated using three different methods: thermograms, elemental formulas, and measured partitioning. Thermogram-based results are consistent with those from an aerosol mass spectrometer (AMS) with a thermal denuder, implying that thermal desorption is reproducible across very different experimental setups...
June 23, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28643509/secondary-copper-smelters-as-sources-of-chlorinated-and-brominated-polycyclic-aromatic-hydrocarbons
#2
Rong Jin, Guorui Liu, Minghui Zheng, Xiaoxu Jiang, Yuyang Zhao, Li Li Yang, Xiaolin Wu, Yang Xu
The generation of and extent to which chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are formed and released from secondary copper smelters remain unknown. This field study, to our knowledge, is the first to identify secondary copper smelters as new sources of Cl/Br-PAHs. Mass concentrations of ∑19Cl-PAHs and ∑19Br-PAHs ranged from 5.8 to 271 ng Nm-3 and 0.59 to 52.4 ng Nm-3, respectively. A comparison of Cl/Br-PAH concentrations in stack gas and fly ash from secondary copper smelters indicated that the use of scrap copper as raw material or the addition of coal or heavy oil as reductant may contribute to the elevated formation and emission of Cl/Br-PAHs...
June 23, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28613841/estimating-a-representative-value-and-proportion-of-true-zeros-for-censored-analytical-data-with-applications-to-contaminated-site-assessment
#3
Claus P Haslauer, Jessica R Meyer, András Bárdossy, Beth L Parker
This paper demonstrates a maximum likelihood (ML)-based approach to derive representative ("best guess") contaminant concentrations from data with censored values (e.g., less than the detection limit). The method represents an advancement over existing techniques because it is capable of estimating the proportion of measurements that are true zeros and incorporating varying levels of censorship (e.g., sample specific detection limits, changes through time in method detection). The ability of the method to estimate the proportion of true zeros is validated using precipitation data...
June 23, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28640610/the-role-of-denitrification-in-stormwater-detention-basin-treatment-of-nitrogen
#4
Natalie R Morse, Lauren Elyse McPhillips, James P Shapleigh, Michael Todd Walter
The nitrogen (N) cycling dynamics of four stormwater basins, two often saturated sites ("Wet Basins") and two quick draining sites ("Dry Basins"), were monitored over a ~1-year period. This study paired stormwater and greenhouse gas monitoring with microbial analyses to elucidate the mechanisms controlling N treatment. Annual dissolved inorganic N (DIN) mass reductions (inflow minus outflow) were greater in the Dry Basin than in the Wet Basin, 2.16 vs. 0.75 g N m-2 yr-1, respectively. The Dry Basin infiltrated a much larger volume of water and thus had greater DIN mass reductions, even though incoming and outgoing DIN concentrations were statistically the same for both sites...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28640607/primary-and-photochemically-aged-aerosol-emissions-from-biomass-cookstoves-chemical-and-physical-characterization
#5
Stephen M Reece, Aditya Sinha, Andrew P Grieshop
Secondary organic aerosol (SOA) formation during photo-oxidation of primary emissions from cookstoves used in developing countries may make important contributions to their climate and air quality impacts. We present results from laboratory experiments with a field portable oxidation flow reactor (F-OFR) to study the evolution of emissions over hours to weeks of equivalent atmospheric aging. Lab tests, using dry red oak, measured fresh and aged emissions from a 3 stone fire (TSF), a "rocket" natural draft stove (NDS) and a forced draft gasifier stove (FDGS), in order of increasing modified combustion efficiency (MCE) and decreasing particulate matter emission factors (EF)...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28640603/changes-in-light-absorptivity-of-molecular-weight-separated-brown-carbon-due-to-photolytic-aging
#6
Jenny Pui Shan Wong, Athanasios Nenes, Rodney J Weber
Brown carbon (BrC) are those organic compounds in atmospheric aerosols that absorb solar radiation and may play an important role on planetary radiative forcing and climate. However, little is known about the production and loss mechanisms of BrC in the atmosphere. Here, we study how the light absorptivity of BrC from wood smoke and secondary BrC generated from reaction of ammonium sulfate with methylglyoxal changes under photolytic aging by UVA radiation in the aqueous phase. Owing to its chemical complexity, BrC is separated by molecular weight using size exclusion chromatography and the response of each molecular weight fraction to aging is studied...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28640599/a-high-throughput-dna-sequencing-approach-to-determine-sources-of-fecal-bacteria-in-a-lake-superior-estuary
#7
Clairessa M Brown, Christopher Staley, Ping Wang, Brent Dalzell, Chan Lan Chun, Michael J Sadowsky
Current microbial source tracking (MST) methods, employed to determine sources of fecal contamination in waterways, use molecular markers targeting host-associated bacteria in animal or human feces. However, there is a lack of knowledge about fecal microbiome composition in several animals and imperfect marker specificity and sensitivity. To overcome these issues, a community-based MST method has been developed. Here, we describe a study done in the Lake Superior-St. Louis River estuary using SourceTracker, a program that calculates the source contribution to an environment...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28640598/structural-and-light-absorption-characteristics-of-complex-water-insoluble-organic-mixtures-in-urban-submicron-aerosols
#8
Qingcai Chen, Fumikazu Ikemori, Yuua Nakamura, Petr Vodicka, Kimitaka Kawamura, Michihiro Mochida
Submicrometer aerosols in the urban atmosphere of Nagoya, Japan, were collected in late winter and early spring, and the water-insoluble organic matter (WISOM) in the samples were fractionated into six subfractions based on their polarities by using solvent and normal-phase solid-phase extractions: non-polar (F1), low-polar (F2 and F3), and medium-polar (F4, F5, and F6) fractions. The overall structural characteristics of these subfractions were then analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-resolution aerosol mass spectrometry...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28605184/modeling-photosensitized-secondary-organic-aerosol-formation-in-laboratory-and-ambient-aerosols
#9
William G Tsui, Yi Rao, Hai-Lung Dai, V Faye McNeill
Photosensitized reactions involving imidazole-2-carboxaldehyde (IC) have been experimentally observed to contribute to secondary organic aerosol (SOA) growth. However, the extent of photosensitized reactions in ambient aerosols remains poorly understood and unaccounted for in atmospheric models. Here we use GAMMA 4.0, a photochemical box model that couples gas-phase and aqueous-phase aerosol chemistry, along with recent laboratory measurements of the kinetics of IC photochemistry, to analyze IC-photosensitized SOA formation in laboratory and ambient settings...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28578575/mercury-temporal-trends-in-top-predator-fish-of-the-laurentian-great-lakes-from-2004-to-2015-are-concentrations-still-decreasing
#10
Chuanlong Zhou, Mark D Cohen, Bernard A Crimmins, Hao Zhou, Timothy A Johnson, Philip K Hopke, Thomas M Holsen
Mercury (Hg) concentration trends in top predator fish (lake trout and walleye) of the Great Lakes (GL) from 2004 to 2015 were determined by Kendall-Theil robust regression with a cluster-based age normalization method to control for the effect of changes in lake trophic status. When data from the GLs (except Lake Erie) are combined, a significant decreasing trend in the lake trout Hg concentrations was found between 2004 and 2015 with an annual decrease of 4.1% per year, consistent with the decline in regional atmospheric Hg emissions and water Hg concentrations...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28558235/tissue-uptake-distribution-and-elimination-of-perfluoroalkyl-substances-in-juvenile-perch-through-perfluorooctane-sulfonamidoethanol-based-phosphate-diester-dietary-exposure
#11
Juliette Gaillard, Bruno Veyrand, Marielle Thomas, Xavier Dauchy, Virginie Boiteux, Philippe Marchand, Bruno Le Bizec, Damien Banas, Cyril Feidt
Perfluorooctane sulfonamidoethanol based phosphate diester (SAmPAP) is a potential perfluorooctanesulfonate (PFOS) precursor. To examine whether SAmPAP exposure would result in fish contamination by perfluoroalkyl and polyfluoroalkyl substances (PFASs), juvenile Eurasian perch were dietarily exposed to this compound (dosed group) or exposed to the same tank water but fed control feed (control group). SAmPAP and metabolites were monitored in the muscle, liver, and serum during the 45-day exposure phase and 35-day depuration phase...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28636817/framework-for-optimizing-selection-of-interspecies-correlation-estimation-models-to-address-species-diversity-and-toxicity-gaps-in-an-aquatic-database
#12
Adriana C Bejarano, Sandy Raimondo, Mace G Barron
The Chemical Aquatic Fate and Effects (CAFE) database is a tool that facilitates assessments of accidental chemical releases into aquatic environments. CAFE contains aquatic toxicity data used in the development of species sensitivity distributions (SSDs) and the estimation of hazard concentrations (HCs). For many chemicals, gaps in species diversity and toxicity data limit the development of SSDs, which may be filled with Interspecies Correlation Estimation (ICE) models. Optimization of ICE model selection and integration ICE-predicted values into CAFE required a multistep process that involved the use of different types of data to assess their influence on SSDs and HC estimates...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28636816/impacts-of-the-mitochondrial-genome-on-the-relationship-of-long-term-ambient-fine-particle-exposure-with-blood-dna-methylation-age
#13
Jamaji Nwanaji-Enwerem, Elena Colicino, Lingzhen Dai, Akin Cayir, Marco Sanchez-Guerra, Hannah E Laue, Vy T Nguyen, Qian Di, Allan Just, Lifang Hou, Pantel Vokonas, Brent A Coull, Marc Weisskopf, Andrea Baccarelli, Joel Schwartz
The mitochondrial genome has long been implicated in age-related disease, but no studies have examined its role in the relationship of long-term fine particle (PM2.5) exposure and DNA methylation age (DNAm-age) - a novel measure of biological age. In this analysis based on 940 observations between 2000 and 2011 from 552 Normative Aging Study participants, we determined the roles of mitochondrial DNA haplogroup variation and mitochondrial genome abundance in the relationship of PM2.5 with DNAm-age. We used the GEOS-chem transport model to estimate address-specific, one-year PM2...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28636383/gene-expression-profiling-in-human-lung-cells-exposed-to-isoprene-derived-secondary-organic-aerosol
#14
Ying-Hsuan Lin, Maiko Arashiro, Phillip W Clapp, Tianqu Cui, Kenneth G Sexton, William Vizuete, Avram Gold, Ilona Jaspers, Rebecca C Fry, Jason Douglas Surratt
Secondary organic aerosol (SOA) derived from the photochemical oxidation of isoprene contributes a substantial mass fraction to atmospheric fine particulate matter (PM2.5). The formation of isoprene SOA is influenced largely by anthropogenic emissions through multiphase chemistry of its multi-generational oxidation products. Considering the abundance of isoprene SOA in the troposphere, understanding mechanisms of adverse health effects through inhalation exposure is critical to mitigating its potential impact on public health...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28636346/halogenated-flame-retardants-in-predator-and-prey-fish-from-the-laurentian-great-lakes-age-dependent-accumulation-and-trophic-transfer
#15
Guanyong Su, Robert J Letcher, Daryl McGoldrick, Sean M Backus
The identification, persistence, accumulation and trophic transfer of 25 polybrominated diphenyl ether (PBDE) congeners, 23 non-PBDE halogenated flame retardants (NPHFRs), 4 polybrominated-diphenoxybenzenes (PB-DiPhOBzs) and 6 methoxylated (MeO-) PB-DiPhOBzs were investigated in predator and prey fish collected in 2010 from sites in the North American Great Lakes of Ontario (n=26) and Erie (n=39). Regardless of locations or species, 20 PBDEs and 12 NPHFRs were quantifiable in at least one of the 65 analyzed samples, and polybrominated-1,4-diphenoxybenzenes (PB-DiPhOBzs) and MeO-PB-DiPhOBzs were not detectable in any of analyzed samples...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28636345/levels-of-organochlorine-pesticides-are-associated-with-amyloid-aggregation-in-apex-avian-brains
#16
Kelly A Heys, Richard F Shore, M Gloria Pereira, Francis Luke Martin
Organochlorine (OC) pesticides pose a significant environmental risk to wildlife and humans and have been associated with Alzheimer's disease (AD). This study aims to spectroscopically analyse brains from free-flying birds and link the results to OC exposure and consequent amyloid aggregation. As long-lived apex predators, predatory birds represent a sentinel species similar to humans. Therefore, the results have implications for both species and may also add to our understanding of the role OC pesticides play in the development of AD...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28636338/contributions-of-local-farming-to-urban-sustainability-in-the-northeast-united-states
#17
Benjamin P Goldstein, Michael Z Hauschild, John E Fernández, Morten Birkved
Food consumption is an important contributor to a city's environmental impacts (carbon emissions, land occupation, water use, etc.) Urban farming (UF) has been advocated as a means to increase urban sustainability by reducing food-related transport and tapping into local resources. Taking Boston as an illustrative Northeast U.S. city, we developed a novel method to estimate sub-urban, food-borne carbon and land footprints using multiregion-input-output modeling and nutritional surveys. Computer simulations utilizing primary data explored UF's ability to reduce these footprints using select farming technologies, building on previous city-scale UF assessments which have hitherto been dependent on proxy data for UF...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28633523/the-effect-of-pseudomonas-fluorescens-on-buried-steel-pipeline-corrosion
#18
Amy J Spark, Ivan S Cole, Adam S Best, David W Law, Liam P Ward
Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influence corrosion (MIC). Localised corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localised corrosion in soil, semi-solid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds and electrochemical impedance spectroscopy it has been shown that P...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28633521/consideration-of-natural-sources-in-a-bacteria-tmdl-lines-of-evidence-including-beach-microbial-source-tracking
#19
Kelly D Goodwin, Alexander Schriewer, Andrew Jirik, Kathryn Curtis, Andrea Crumpacker
Total Maximum Daily Load (TMDL) stipulations remained unmet at a southern California beach despite a suite of management actions carried out since 2001, prompting exploration of a Natural Sources Exclusion (NSE) provision within the TMDL. Quantitative Microbial Source Tracking (MST) was employed from 2012-2015 to inventory sources of natural and anthropogenic fecal indicator bacteria (FIB). Data suggested FIB exceedances could be traced to gulls based on gull marker prevalence and correlations with FIB concentrations in seawater, sand and eelgrass...
June 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28599109/viral-aggregation-impact-on-virus-behavior-in-the-environment
#20
Charles P Gerba, Walter Q Betancourt
Aggregates of viruses can have a significant impact on quantification and behavior of viruses in the environment. Viral aggregates may be formed in numerous ways. Viruses may form crystal like structures and aggregates in the host cell during replication or may form due to changes in environmental conditions after virus particles are released from the host cells. Aggregates tend to form near the isoelectric point of the virus, under the influence of certain salts and salt concentrations in solution, cationic polymers, and suspended organic matter...
June 21, 2017: Environmental Science & Technology
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