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Building materials. VOC emissions, diffusion behaviour and implications from their use
2012
Katsoyiannis, Athanasios | Leva, Paolo | Barrero-Moreno, Josefa | Kotzias, Dimitrios
Five cement- and five lime-based building materials were examined in an environmental chamber for their emissions of Volatile Organic Compounds (VOCs). Typical VOCs were below detection limits, whereas not routinely analysed VOCs, like neopentyl glycol (NPG), dominated the cement-based products emissions, where, after 72 h, it was found to occur, in levels as high as 1400 μg m⁻³, accounting for up to 93% of total VOCs. The concentrations of NPG were not considerably changed between the 24 and 72 h of sampling. The permeability of building materials was assessed through experiments with a dual environmental chamber; it was shown that building materials facilitate the diffusion of chemicals through their pores, reaching equilibrium relatively fast (6 h).
Mostrar más [+] Menos [-]Field assessment of a snap bean ozone bioindicator system under elevated ozone and carbon dioxide in a free air system
2012
Burkey, Kent O. | Booker, Fitzgerald L. | Ainsworth, Elizabeth A. | Nelson, Randall L.
Ozone-sensitive (S156) and -tolerant (R123 and R331) genotypes of snap bean (Phaseolus vulgaris L.) were tested as a plant bioindicator system for detecting O₃ effects at current and projected future levels of tropospheric O₃ and atmospheric CO₂ under field conditions. Plants were treated with ambient air, 1.4× ambient O₃ and 550 ppm CO₂ separately and in combination using Free Air Concentration Enrichment technology. Under ambient O₃ concentrations pod yields were not significantly different among genotypes. Elevated O₃ reduced pod yield for S156 (63%) but did not significantly affect yields for R123 and R331. Elevated CO₂ at 550 ppm alone did not have a significant impact on yield for any genotype. Amelioration of the O₃ effect occurred in the O₃ + CO₂ treatment. Ratios of sensitive to tolerant genotype pod yields were identified as a useful measurement for assessing O₃ impacts with potential applications in diverse settings including agricultural fields.
Mostrar más [+] Menos [-]DNA-damage effect of polycyclic aromatic hydrocarbons from urban area, evaluated in lung fibroblast cultures
2012
Teixeira, Elba Calesso | Pra, Daniel | Idalgo, Daniele | Henriques, João Antonio Pêgas | Wiegand, Flavio
This study was designed to biomonitor the effect of PAH extracts from urban areas on the DNA of lung cell cultures. The analyses of the polycyclic aromatic hydrocarbons (PAHs) were performed in atmospheric PM₂.₅ and PM₁₀ collected at three sampling sites with heavy traffic located in the Metropolitan Area of Porto Alegre (MAPA) (Brazil). The concentrations of 16 major PAHs were determined according to EPA. Comet assay on V79 hamster lung cells was chosen for genotoxicity evaluation. Temperature, humidity, and wind speed were recorded. With regard to the damage index, higher levels were reported in the extract of particulate matter samples from the MAPA during the summer. High molecular weight compounds showed correlation with DNA damage frequency and their respective carcinogenicity.
Mostrar más [+] Menos [-]A sediment ecotoxicity assessment platform for in situ measures of chemistry, bioaccumulation and toxicity. Part 2: Integrated application to a shallow estuary
2012
Rosen, Gunther | Bart Chadwick, D. | Allen Burton, G. | Keith Taulbee, W. | Greenberg, Marc S. | Lotufo, Guilherme R. | Reible, Danny D.
A comprehensive, weight-of-evidence based ecological risk assessment approach integrating laboratory and in situ bioaccumulation and toxicity testing, passive sampler devices, hydrological characterization tools, continuous water quality sensing, and multi-phase chemical analyses was evaluated. The test site used to demonstrate the approach was a shallow estuarine wetland where groundwater seepage and elevated organic and inorganic contaminants were of potential concern. Although groundwater was discharging into the surficial sediments, little to no chemical contamination was associated with the infiltrating groundwater. Results from bulk chemistry analysis, toxicity testing, and bioaccumulation, however, suggested possible PAH toxicity at one station, which might have been enhanced by UV photoactivation, explaining the differences between in situ and laboratory amphipod survival. Concurrently deployed PAH bioaccumulation on solid-phase micro-extraction fibers positively correlated (r² ≥ 0.977) with in situ PAH bioaccumulation in amphipods, attesting to their utility as biomimetics, and contributing to the overall improved linkage between exposure and effects demonstrated by this approach.
Mostrar más [+] Menos [-]Quantifying the impacts of socio-economic factors on air quality in Chinese cities from 2000 to 2009
2012
Zhao, Juanjuan | Chen, Shengbin | Wang, Hua | Ren, Yin | Du, Ke | Xu, Weihua | Zheng, Hua | Jiang, Bo
Socio-economic factors have significant influences on air quality and are commonly used to guide environmental planning and management. Based on data from 85 long-term daily monitoring cities in China, air quality as evaluated by AOFDAQ-A (Annual Occurrence Frequency of Daily Air Quality above Level III), was correlated to socio-economic variable groups of urbanization, pollution and environmental treatment by variation partitioning and hierarchical partitioning methods. We found: (1) the three groups explained 43.5% of the variance in AOFDAQ-A; (2) the contribution of “environmental investment” to AOFDAQ-A shown a time lag effect; (3) “population in mining sector” and “coverage of green space in built-up area” were respectively the most significant negative and positive explanatory socio-economic variables; (4) using eight largest contributing individual factors, a linear model to predict variance in AOFDAQ-A was constructed. Results from our study provide a valuable reference for the management and control of air quality in Chinese cities.
Mostrar más [+] Menos [-]Cosorption of organic chemicals with different properties: Their shared and different sorption sites
2012
Zhang, Di | Pan, Bo | Wu, Min | Zhang, Huang | Peng, Hongbo | Ning, Ping | Xing, Baoshan
Complementary sorption of different chemicals was expected and investigating the relationship between the sorption inhibition of primary sorbate (ΔQᵖʳⁱ) and sorption of secondary sorbate (Qˢᵉᶜ) could provide a new angle to understand coadsorption of different chemicals. This study used bisphenol A (BPA) as the primary adsorbate, sulfamethoxazole (SMX) as the competitor, and carbon nanotubes as model adsorbents to study their complementary and competitive adsorption. At low BPA concentrations, the sorption of SMX (Qˢᵉᶜ) exceeded BPA sorption inhibition (ΔQᵖʳⁱ), indicating that these two chemicals complementarily adsorbed on their respectively preferred sorption sites. At high BPA concentrations, higher ΔQᵖʳⁱ was observed in comparison to Qˢᵉᶜ, which may be resulted from different packing efficiencies of the adsorbed SMX and BPA. This study emphasized that both competitive and complementary sorption should be discussed in binary sorption system.
Mostrar más [+] Menos [-]Fate of Triclosan and Methyltriclosan in soil from biosolids application
2012
Lozano, Nuria | Rice, Clifford P. | Ramirez, Mark | Torrents, Alba
This study investigates the persistence of Triclosan (TCS), and its degradation product, Methyltriclosan (MeTCS), after land application of biosolids to an experimental agricultural plot under both till and no till. Surface soil samples (n = 40) were collected several times over a three years period and sieved to remove biosolids. Concentration of TCS in the soil gradually increased with maximum levels of 63.7 ± 14.1 ng g⁻¹ dry wt., far below the predicted maximum concentration of 307.5 ng g⁻¹ dry wt. TCS disappearance corresponded with MeTCS appearance, suggesting in situ formation. Our results suggest that soil incorporation and degradation processes are taking place simultaneously and that TCS background levels are achieved within two years. TCS half-life (t₀.₅) was determined as 104 d and MeTCS t₀.₅, which was more persistent than TCS, was estimated at 443 d.
Mostrar más [+] Menos [-]Global gene expression in larval zebrafish (Danio rerio) exposed to selective serotonin reuptake inhibitors (fluoxetine and sertraline) reveals unique expression profiles and potential biomarkers of exposure
2012
Park, June Woo | Heah, Tze Ping | Gouffon, Julia S. | Henry, Theodore B. | Sayler, Gary S.
Larval zebrafish (Danio rerio) were exposed (96 h) to selective serotonin reuptake inhibitors (SSRIs) fluoxetine and sertraline and changes in transcriptomes analyzed by Affymetrix GeneChip® Zebrafish Array were evaluated to enhance understanding of biochemical pathways and differences between these SSRIs. The number of genes differentially expressed after fluoxetine exposure was 288 at 25μg/L and 131 at 250μg/L; and after sertraline exposure was 33 at 25μg/L and 52 at 250μg/L. Same five genes were differentially regulated in both SSRIs indicating shared molecular pathways. Among these, the gene coding for FK506 binding protein 5, annotated to stress response regulation, was highly down-regulated in all treatments (results confirmed by qRT-PCR). Gene ontology analysis indicated at the gene expression level that regulation of stress response and cholinesterase activities were influenced by these SSRIs, and suggested that changes in transcription of these genes could be used as biomarkers of SSRI exposure.
Mostrar más [+] Menos [-]Using disposable solid-phase microextraction (SPME) to determine the freely dissolved concentration of polybrominated diphenyl ethers (PBDEs) in sediments
2012
Jia, Fang | Cui, Xinyi | Wang, Wei | Delgado-Moreno, Laura | Gan, Jay
Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants (BFRs). The ubiquity and persistence of PBDEs in sediment have raised concerns over their environmental fate and ecological risks. Due to strong affinity for sediment organic matter, environmental fate and bioavailability of PBDEs closely depend on their phase distribution. In this study, disposable polydimethylsiloxane (PDMS) fiber was used to derive the freely dissolved concentration (Cfᵣₑₑ) of PBDEs in sediment porewater as a measurement of bioavailability. The PDMS-to-water partition coefficient (log KPDMS) was 5.46–5.83 for BDE 47, 99, and 153. In sediments, PBDEs were predominantly sorbed to the sediment phase, with Cfᵣₑₑ accounting for <0.012% of the total chemical mass. The Cfᵣₑₑ of PBDEs decreased as their bromination or sediment organic carbon content increased. The strong association with dissolved organic matter (DOM) implies a potential for facilitated offsite transport and dispersion in the environment that depends closely on the stability of sediment aggregates.
Mostrar más [+] Menos [-]Modeling and validation of on-road CO₂ emissions inventories at the urban regional scale
2012
Brondfield, Max N. | Hutyra, Lucy R. | Gately, Conor K. | Raciti, Steve M. | Peterson, Scott A.
On-road emissions are a major contributor to rising concentrations of atmospheric greenhouse gases. In this study, we applied a downscaling methodology based on commonly available spatial parameters to model on-road CO₂ emissions at the 1 × 1 km scale for the Boston, MA region and tested our approach with surface-level CO₂ observations. Using two previously constructed emissions inventories with differing spatial patterns and underlying data sources, we developed regression models based on impervious surface area and volume-weighted road density that could be scaled to any resolution. We found that the models accurately reflected the inventories at their original scales (R² = 0.63 for both models) and exhibited a strong relationship with observed CO₂ mixing ratios when downscaled across the region. Moreover, the improved spatial agreement of the models over the original inventories confirmed that either product represents a viable basis for downscaling in other metropolitan regions, even with limited data.
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