Refine search
Results 231-240 of 1,955
Global climate change: Impact of diurnal temperature range on mortality in Guangzhou, China Full text
2013
Yang, Jun | Liu, Hua-Zhang | Ou, Chun-Quan | Lin, Guo-Zhen | Zhou, Qin | Shen, Gi-Chuan | Chen, Ping-Yan | Guo, Yuming
Diurnal temperature range (DTR) is an important meteorological indicator associated with global climate change, but little is known about the effects of DTR on mortality. We examined the effects of DTR on cause-/age-/education-specific mortality in Guangzhou, a subtropical city in China during 2003–2010. A quasi-Poisson regression model combined with distributed lag non-linear model was used to examine the effects of DTR, after controlling for daily mean temperature, air pollutants, season and day of the week. A 1 °C increase in DTR at lag 0–4 days was associated with a 0.47% (95% confidence interval: 0.01%–0.93%) increase in non-accidental mortality. Stroke mortality was most sensitive to DTR. Female, the elderly and those with low education were more susceptible to DTR than male, the youth and those with high education, respectively. Our findings suggest that vulnerable subpopulations should pay more attention to protect themselves from unstable daily weather.
Show more [+] Less [-]A stable isotope dilution method for measuring bioavailability of organic contaminants Full text
2013
Delgado-Moreno, Laura | Gan, Jay
Methods for determining bioavailability of organic contaminants suffer various operational limitations. We explored the use of stable isotope labeled references in developing an isotope dilution method (IDM) to measure the exchangeable pool (E) of pyrene and bifenthrin as an approximation of their bioavailability in sediments. The exchange of deuterated bifenthrin or pyrene with its native counterpart was completed within 48 h. The derived E was 38–82% for pyrene and 28–59% for bifenthrin. Regression between E and the sum of rapid and slow desorption fractions obtained from sequential desorption showed a slope close to 1.0. The ability of IDM to predict bioavailability was further shown from a strong relationship (r2 > 0.93) between E and bioaccumulation into Chironomus tentans. Given the abundance of stable isotope labeled references and their relatively easy analysis, the IDM has the potential to become a readily adoptable tool for estimating organic contaminants bioaccessibility in various matrices.
Show more [+] Less [-]Effects of plant species on soil microbial processes and CH4 emission from constructed wetlands Full text
2013
Wang, Yanhua | Yang, Hao | Ye, Chun | Chen, Xia | Xie, Biao | Huang, Changchun | Zhang, Jixiang | Xu, Meina
Methane (CH4) emission from constructed wetland has raised environmental concern. This study evaluated the influence of mono and polyculture constructed wetland and seasonal variation on CH4 fluxes. Methane emission data showed large temporal variation ranging from 0 to 249.29 mg CH4 m−2 h−1. Results indicated that the highest CH4 flux was obtained in the polyculture system, planted with Phragmites australis, Zizania latifolia and Typha latifolia, reflecting polyculture system could stimulate CH4 emission. FISH analysis showed the higher amount of methanotrophs in the profile of Z. latifolia in both mono and polyculture systems. The highest methanogens amount and relatively lower methanotrophs amount in the profile of polyculture system were obtained. The results support the characteristics of CH4 fluxes. The polyculture constructed wetland has the higher potential of global warming.
Show more [+] Less [-]Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta Full text
2013
Korosi, J.B. | Irvine, G. | Skierszkan, E.K. | Doyle, J.R. | Kimpe, L.E. | Janvier, J. | Blais, J.M.
The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ∼1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies.
Show more [+] Less [-]Space and time resolved monitoring of airborne particulate matter in proximity of a traffic roundabout in Sweden Full text
2013
Wilkinson, Kai E. | Lundkvist, Johanna | Netrval, Julia | Eriksson, Mats | Seisenbaeva, Gulaim A. | Kessler, Vadim G.
Concerns over exposure to airborne particulate matter (PM) are on the rise. Currently monitoring of PM is done on the basis of interpolating a mass of PM by volume (μg/m3) but has the drawback of not taking the chemical nature of PM into account. Here we propose a method of collecting PM at its emission source and employing automated analysis with scanning electron microscopy associated with EDS-analysis together with light scattering to discern the chemical composition, size distribution, and time and space resolved structure of PM emissions in a heavily trafficated roundabout in Sweden. Multivariate methods (PCA, ANOVA) indicate that the technogenic marker Fe follows roadside dust in spreading from the road, and depending on time and location of collection, a statistically significant difference can be seen, adding a useful tool to the repertoiré of detailed PM monitoring and risk assessment of local emission sources.
Show more [+] Less [-]Magnetic susceptibility measurements to detect coal fly ash from the Kingston Tennessee spill in Watts Bar Reservoir Full text
2013
Cowan, Ellen A. | Seramur, Keith C. | Hageman, Steven J.
An estimated 229 000 m3 of coal fly ash remains in the river system after dredging to clean-up the 2008 Tennessee Valley Authority (TVA) spill in Kingston, Tennessee. The ash is heterogeneous with clear, orange and black spheres and non-spherical amorphous particles. Combustion produces iron oxides that allow low field magnetic susceptibility (χLF) and percent frequency dependent susceptibility (χFD%) to be used to discriminate between coal fly ash and sediments native to the watershed. Riverbed samples with χLF greater than 3.0 × 10−6 m3/kg, have greater than 15% ash measured by optical point counting. χLF is positively correlated with total ash, allowing ash detection in riverbed sediments and at depth in cores. The ratio of ash sphere composition is altered by river transport introducing variability in χLF. Measurement of χLF is inexpensive, non-destructive, and a reliable analytical tool for monitoring the fate of coal ash in this fluvial environment.
Show more [+] Less [-]Temporal variations of perfluoroalkyl substances and polybrominated diphenyl ethers in alpine snow Full text
2013
Kirchgeorg, Torben | Dreyer, Annekatrin | Gabrieli, Jacopo | Kehrwald, Natalie | Sigl, Michael | Schwikowski, Margit | Boutron, Claude | Gambaro, Andrea | Barbante, Carlo | Ebinghaus, Ralf
The occurrence and temporal variation of 18 perfluoroalkyl substances (PFASs) and 8 polybrominated diphenyl ethers (PBDEs) in the European Alps was investigated in a 10 m shallow firn core from Colle Gnifetti in the Monte Rosa Massif (4455 m above sea level). The firn core encompasses the years 1997–2007. Firn core sections were analyzed by liquid chromatography–tandem mass spectrometry (PFASs) and gas chromatography–mass spectrometry (PBDEs). We detected 12 PFASs and 8 PBDEs in the firn samples. Perfluorobutanoic acid (PFBA; 0.3–1.8 ng L−1) and perfluorooctanoic acid (PFOA; 0.2–0.6 ng L−1) were the major PFASs while BDE 99 (<MQL–4.5 ng L−1) and BDE 47 (n.d.–2.6 ng L−1) were the major PBDEs. This study demonstrates the occurrence of PFASs and PBDEs in the European Alps and provides the first evidence that PFASs compositions may be changing to PFBA-dominated compositions.
Show more [+] Less [-]High-resolution reconstruction of atmospheric deposition of trace metals and metalloids since AD 1400 recorded by ombrotrophic peat cores in Hautes-Fagnes, Belgium Full text
2013
Allan, Mohammed | Le Roux, Gaël | De Vleeschouwer, François | Bindler, Richard | Blaauw, Maarten | Piotrowska, Natalia | Sikorski, Jaroslaw | Fagel, Nathalie
The objective of our study was to determine the trace metal accumulation rates in the Misten bog, Hautes-Fagnes, Belgium, and assess these in relation to established histories of atmospheric emissions from anthropogenic sources. To address these aims we analyzed trace metals and metalloids (Pb, Cu, Ni, As, Sb, Cr, Co, V, Cd and Zn), as well as Pb isotopes, using XRF, Q-ICP-MS and MC-ICP-MS, respectively in two 40-cm peat sections, spanning the last 600 yr. The temporal increase of metal fluxes from the inception of the Industrial Revolution to the present varies by a factor of 5–50, with peak values found between AD 1930 and 1990. A cluster analysis combined with Pb isotopic composition allows the identification of the main sources of Pb and by inference of the other metals, which indicates that coal consumption and metallurgical activities were the predominant sources of pollution during the last 600 years.
Show more [+] Less [-]Biomarker responses reveal that food quality affects cadmium exposure in the soil collembolan Folsomia candida Full text
2013
Nakamori, Taizo | Kaneko, Nobuhiro
Food quality affects the food consumption rate, flux through the gut, and exposure to contaminants in animals. This study evaluated the effects of food quality on cadmium exposure in the soil collembolan Folsomia candida. Animals were exposed to constant concentrations of cadmium for 38 h via artificial food consisting of an agar medium with various concentrations of sugar (glucose), total nutrients (baker's yeast), or fungal odour (1-octen-3-ol). The expression of the gene encoding a deduced metallothionein-like motif containing protein was used as a biomarker of cadmium exposure. Glucose concentrations of 2% or higher reduced the expression levels of the biomarker. Within the range of 0.1–8% yeast, medium concentrations led to higher biomarker levels. At high concentrations of 1-octen-3-ol (2000 mg/l), feeding and the biomarker response were reduced. These results suggest that even at equivalent cadmium concentrations, food quality affects cadmium exposure by altering food consumption rates.
Show more [+] Less [-]Personal exposure to benzene of selected population groups and impact of commuting modes in Ho Chi Minh, Vietnam Full text
2013
Lan, Tran Thi Ngoc | Liem, Ngo Quang | Binh, Nguyen Thi Thanh
Personal exposure to benzene of selected population groups, and impacts of traffic on commuters in Ho Chi Minh City were investigated. The study was carried out in June, July and November 2010. The preliminary data showed that on average, personal exposure to benzene for non-occupational people in Ho Chi Minh is ∼18 μg/m3 and most of the exposure is due to commuting. Benzene exposure during travelling by bus, taxi and motorcycle is, respectively, 22–30, 22–39 and 185–240 μg/m3. Motorcycle–taxi drivers, petrol filling employees and street vendors suffer high daily exposures at 116, 52, 32 μg/m3, respectively. Further measurements are needed for a better risk assessment and finding effective measures to reduce exposure.
Show more [+] Less [-]