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النتائج 101 - 110 من 3,243
Fractionation and mobility of Cu, Fe, Mn, Pb and Zn in the road dust retained on noise barriers along expressway – A potential tool for determining the effects of driving conditions on speciation of emitted particulate metals
2015
Świetlik, Ryszard | Trojanowska, Marzena | Strzelecka, Monika | Bocho-Janiszewska, Anita
Road dust (RD) retained on noise barriers was used as a monitor of emission of traffic-related metals from expressway. By using SEM/EDX analysis it has been revealed that the main components of this particulate were irregular fine aggregates and tire debris with a ragged porous structure and with inclusions derived from the road surface. The results of chemical fractionation showed that driving conditions influence strongly a distribution pattern of Cu, whereas the atmospheric corrosion process affects a distribution pattern of Zn. The distribution pattern of Cu originating only from vehicle braking emission was “isolated” from the distribution pattern of road traffic copper. The predicted comparative mobilities of the emitted metals form the order: Zn >> Cu ≈ Mn > Pb >> Fe. The high mobility of zinc (K = 0.61) may create a current inhalation hazard and may be a source of future environmental hazard in the areas adjacent to heavily trafficked roads.
اظهر المزيد [+] اقل [-]Proteomic profile in Perna viridis after exposed to Prorocentrum lima, a dinoflagellate producing DSP toxins
2015
Huang, Lu | Zou, Ying | Weng, Hui-wen | Li, Hong-Ye | Liu, Jie-Sheng | Yang, Wei-Dong
In the current study, we compared protein profiles in gills of Perna viridis after exposure to Prorocentrum lima, a dinoflagellate producing DSP toxins, and identified the differential abundances of protein spots using 2D-electrophoresis. After exposure to P. lima, the level of okadaic acid (a main component of DSP toxins) in gills of P. viridis significantly increased at 6 h, but mussels were all apparently healthy without death. Among the 28 identified protein spots by MALDI TOF/TOF-MS, 12 proteins were up-regulated and 16 were down-regulated in the P. lima-exposed mussels. These identified proteins were involved in various biological activities, such as metabolism, cytoskeleton, signal transduction, response to oxidative stress and detoxification. Taken together, our results indicated that the presence of P. lima caused DSP toxins accumulation in mussel gill, and might consequently induce cytoskeletonal disorganization, oxidative stress, a dysfunction in metabolism and ubiquitination/proteasome activity.
اظهر المزيد [+] اقل [-]The effects of short- and long-term air pollutants on plant phenology and leaf characteristics
2015
Jochner, Susanne | Markevych, Iana | Beck, Isabelle | Traidl-Hoffmann, Claudia | Heinrich, Joachim | Menzel, Annette
Pollution adversely affects vegetation; however, its impact on phenology and leaf morphology is not satisfactorily understood yet. We analyzed associations between pollutants and phenological data of birch, hazel and horse chestnut in Munich (2010) along with the suitability of leaf morphological parameters of birch for monitoring air pollution using two datasets: cumulated atmospheric concentrations of nitrogen dioxide and ozone derived from passive sampling (short-term exposure) and pollutant information derived from Land Use Regression models (long-term exposure). Partial correlations and stepwise regressions revealed that increased ozone (birch, horse chestnut), NO2, NOx and PM levels (hazel) were significantly related to delays in phenology. Correlations were especially high when rural sites were excluded suggesting a better estimation of long-term within-city pollution. In situ measurements of foliar characteristics of birch were not suitable for bio-monitoring pollution. Inconsistencies between long- and short-term exposure effects suggest some caution when interpreting short-term data collected within field studies.
اظهر المزيد [+] اقل [-]Quantifying the effect of vegetation on near-road air quality using brief campaigns
2015
Tong, Zheming | Whitlow, Thomas H. | MacRae, Patrick F. | Landers, Andrew J. | Harada, Yoshiki
Many reports of trees' impacts on urban air quality neglect pattern and process at the landscape scale. Here, we describe brief campaigns to quantify the effect of trees on the dispersion of airborne particulates using high time resolution measurements along short transects away from roads. Campaigns near major highways in Queens, NY showed frequent, stochastic spikes in PM2.5. The polydisperse PM2.5 class poorly represented the behavior of discrete classes. A transect across a lawn with trees had fewer spikes in PM2.5 concentration but decreased more gradually than a transect crossing a treeless lawn. This coincided with decreased Turbulence Kinetic Energy downwind of trees, indicating recirculation, longer residence times and decreased dispersion. Simply planting trees can increase local pollution concentrations, which is a special concern if the intent is to protect vulnerable populations. Emphasizing deposition to leaf surfaces obscures the dominant impact of aerodynamics on local concentration.
اظهر المزيد [+] اقل [-]The discharge of certain amounts of industrial microplastic from a production plant into the River Danube is permitted by the Austrian legislation
2015
Lechner, Aaron | Ramler, David
Numerous studies have quantified the amount of plastic litter in aquatic ecosystems and tried to assess its impacts and threats. This reflects a rising awareness of plastic as an environmental problem. As a next logical step, identifying and regulating the sources must be in the focus of scientific efforts. We report on a spillage of industrial microplastic (IMP) from a production plant situated at an Austrian Danube tributary. This is the first identified point source of IMP litter in freshwater systems. However, due to generous thresholds established by the Austrian government substantial amounts of IMP are legally introduced into running waters.
اظهر المزيد [+] اقل [-]Genetic variation of Lymnaea stagnalis tolerance to copper: A test of selection hypotheses and its relevance for ecological risk assessment
2015
Côte, Jessica | Bouétard, Anthony | Pronost, Yannick | Besnard, Anne-Laure | Coke, Maïra | Piquet, Fabien | Caquet, Thierry | Coutellec, Marie-Agnès
The use of standardized monospecific testing to assess the ecological risk of chemicals implicitly relies on the strong assumption that intraspecific variation in sensitivity is negligible or irrelevant in this context. In this study, we investigated genetic variation in copper sensitivity of the freshwater snail Lymnaea stagnalis, using lineages stemming from eight natural populations or strains found to be genetically differentiated at neutral markers. Copper-induced mortality varied widely among populations, as did the estimated daily death rate and time to 50% mortality (LT50).Population genetic divergence in copper sensitivity was compared to neutral differentiation using the QST-FST approach. No evidence for homogenizing selection could be detected. This result demonstrates that species-level extrapolations from single population studies are highly unreliable. The study provides a simple example of how evolutionary principles could be incorporated into ecotoxicity testing in order to refine ecological risk assessment.
اظهر المزيد [+] اقل [-]Spatial analysis of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (Sea-Nine 211) concentrations and probabilistic risk to marine organisms in Hiroshima Bay, Japan
2015
Mochida, Kazuhiko | Hano, Takeshi | Onduka, Toshimitsu | Ichihashi, Hideki | Amano, Haruna | Ito, Mana | Ito, Katsutoshi | Tanaka, Hiroyuki | Fujii, Kazunori
We analyzed the spatial distribution of an antifouling biocide, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (Sea-Nine 211) in the surface water and sediments of Hiroshima Bay, Japan to determine the extent of contamination by this biocide. A quantitative estimate of the environmental concentration distribution (ECD) and species sensitivity distributions (SSDs) for marine organisms were derived by using a Bayesian statistical model to carry out a probabilistic ecological risk analysis, such as calculation of the expected potentially affected fraction (EPAF). The spatial distribution analysis supported the notion that Sea-Nine 211 is used mainly for treatment of ship hulls in Japan. The calculated EPAF suggests that approximately up to a maximum of 0.45% of marine species are influenced by the toxicity of Sea-Nine 211 in Hiroshima Bay. In addition, estimation of the ecological risk with a conventional risk quotient method indicated that the risk was a cause for concern in Hiroshima Bay.
اظهر المزيد [+] اقل [-]Impact of 70 years urban growth associated with heavy metal pollution
2015
Rodríguez Martín, J.A. | De Arana, C. | Ramos-Miras, J.J. | Gil, C. | Boluda, R.
Historical trends in trace element deposition were analyzed using herbaria specimens. We determined Al, Fe, Mg, Mn, Ca, Na, P, K, S, As, Cd, Cr, Cu, Ni, Pb and Zn contents in leaves of eight specimens collected in 1941. To assess changes, we collected the same plants from a botanical garden in 2012. The concentrations of major elements showed large species variability. However, temporal trends were predominately detected for heavy metals. The Cd, Ni and Cr contents in the 2012 leaves were 10, 13 and 16 times higher, respectively, than in 1941. Urban activities have substantially raised the levels of these metals in urban atmospheres due to changes in human activities over 70 years of urban growth. Nevertheless, Pb has decreased (−126%) in recent decades thanks to controlled lead fuel combustion. In short, metal deposition trend to increase Cr, Ni and Cd levels.
اظهر المزيد [+] اقل [-]Source contributions and regional transport of primary particulate matter in China
2015
Hu, Jianlin | Wu, Li | Zheng, Bo | Zhang, Qiang | He, Kebin | Chang, Qing | Li, Xinghua | Yang, Fumo | Ying, Qi | Zhang, Hongliang
A source-oriented CMAQ was applied to determine source sector/region contributions to primary particulate matter (PPM) in China. Four months were simulated with emissions grouped to eight regions and six sectors. Predicted elemental carbon (EC), primary organic carbon (POC), and PPM concentrations and source contributions agree with measurements and have significant spatiotemporal variations. Residential is a major contributor to spring/winter EC (50–80%), POC (60%–90%), and PPM (30–70%). For summer/fall, industrial contributes 30–50% for EC/POC and 40–60% for PPM. Transportation is more important for EC (20–30%) than POC/PPM (<5%). Open burning is important in summer/fall of Guangzhou and Chongqing. Dust contributes to 1/3–1/2 in spring/fall of Beijing, Xi'an and Chongqing. Based on sector–region combination, local residential/transportation and residential/industrial from Heibei are major contributors to spring PPM in Beijing. In summer/fall, local industrial is the largest. In winter, residential/industrial from local and Hebei account for >90% in Beijing.
اظهر المزيد [+] اقل [-]Lanthanide ecotoxicity: First attempt to measure environmental risk for aquatic organisms
2015
González, Verónica | Vignati, Davide A.L. | Pons, Marie-Noëlle | Montarges-Pelletier, Emmanuelle | Bojic, Clément | Giamberini, Laure
The geochemical cycles of lanthanides are being disrupted by increasing global production and human use, but their ecotoxicity is not fully characterized. In this study, the sensitivity of Aliivibrio fischeri and Pseudokirchneriella subcapitata to lanthanides increased with atomic number, while Daphnia magna, Heterocypris incongruens, Brachionus calyciflorus and Hydra attenuata were equally sensitive to the tested elements. In some cases, a marked decrease in exposure concentrations was observed over test duration and duly considered in calculating effect concentrations and predicted no effect concentrations (PNEC) for hazard and risk assessment. Comparison of PNEC with measured environmental concentrations indicate that, for the present, environmental risks deriving from lanthanides should be limited to some hotspots (e.g., downstream of wastewater treatment plants). However, considering the increasing environmental concentrations of lanthanides, the associated risks could become higher in the future. Ecotoxicological and risk assessment studies, along with monitoring, are required for properly managing these emerging contaminants.
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