خيارات البحث
النتائج 1181 - 1190 من 4,044
Development of a solid-phase extraction system modified for preconcentration of emerging contaminants in large sample volumes from rivers of the lagoon system in the city of Rio de Janeiro, Brazil النص الكامل
2016
Lopes, Vitor Sergio Almeida | Riente, Roselene Ribeiro | da Silva, Alexsandro Araújo | Torquilho, Delma Falcão | Carreira, Renato da Silva | Marques, Mônica Regina da Costa
A single method modified for monitoring of emerging contaminants in river water was developed for large sample volumes. Water samples from rivers of the lagoon system in the city of Rio de Janeiro (Brazil) were analyzed by the SPE-HPLC-MS-TOF analytical method. Acetaminophen was detected in four rivers in the concentration range of 0.09μgL−1 to 0.14μgL−1. Salicylic acid was also found in the four rivers in the concentration range of 1.65μgL−1 to 4.81μgL−1. Bisphenol-A was detected in all rivers in the concentration range of 1.37μgL−1 to 39.86μgL−1. Diclofenac was found in only one river, with concentration of 0.22μgL−1. The levels of emerging organic pollutants in the water samples of the Jacarepaguá hydrographical basin are significant. The compounds are not routinely monitored and present potential risks to environmental health.
اظهر المزيد [+] اقل [-]Sensitivity of online coupled model to extreme pollution event over a mega city Delhi النص الكامل
2016
Srinivas, Reka | Panicker, Abhilash S. | Parkhi, Neha S. | Peshin, Sunil K. | Beig, Gufran
Sensitivity of interactive Weather-Chemistry model has been examined to predict the air quality (1 and 3 days in advance) of Indian mega city Delhi during two identical extreme events of Diwali in 2012 and 2013. Analysis is conducted 3 days prior to 3 days later of Diwali day for both events to verify the rapid changes in fine particulate matter (PM2.5) due to widespread display of Diwali fireworks. The model successfully predicted the variability in PM2.5 during 2012 for the entire period of analysis with reasonable accuracy. Although model performed reasonably well until Diwali day in 2013 but it was unable to simulate rapid built up of PM2.5 (1500 μg−3 hourly average) during post Diwali day as it failed to capture unusual mid-night steep temperature gradient followed by a record lowering of boundary layer height. The predictability of the model and its limitation to micrometeorological processes are discussed in detail.
اظهر المزيد [+] اقل [-]OC/EC from PM10 in the vicinity of Turów lignite open-pit mine (SW Poland): Carbon isotopic approach النص الكامل
2016
Kosztowniak, Elżbieta | Ciężka, Monika | Zwoździak, Anna | Górka, Maciej
Concentrations of PM10 (particulate matter less than 10 μm in diameter) were measured at sampling points located in the vicinity of the Turów open-pit mine, southwest Poland, in April 2008. The samples were analysed by isotope ratio mass spectrometry (IR-MS) to determine the stable carbon isotope compositions of organic carbon (δ13COC) and elemental carbon (δ13CEC). The daily PM10 concentrations ranged from 15 to 99 μg m−3 with an average value of 50 ± 24 μg m−3. The analysed δ13COC values ranged from −25.1 to −19.9‰ with an average value of −23.1 ± 1.9‰, and the values of δ13CEC ranged from −25.6 to −24.1‰ with an average value of −25.0 ± 0.5‰. Additionally, the average δ13CTC value of lignite from the open-pit mine reached −25.8‰, and calculated δ13COC of lignite using an isotopic mass balance (IMB) value reaches −25.7 ± 0.1‰, whereas lignite δ13CEC value reaches −25.9 ± 0.2‰. The calculated major possible sources indicated that organic carbon (OC) in PM10 are represented probably by primary OC originated from the local lignite open-pit mine, whereas elemental carbon (EC) in PM10 are probably derived from local coal/lignite combustion products. If a data base of δ13COC and δ13CEC values from other possible “pure” sources (coal/gasoline/diesel/biomass/etc) is created, it will be possible to calculate individual isotopic mass balances for OC and for EC, which would yield more information than was obtained for total carbon (TC). The method could be a new and very helpful tool for calculating the percentage input of possible sources of OC and EC in atmospheric particles, and it can be applied to data from locations throughout the whole world.
اظهر المزيد [+] اقل [-]Distribution and contamination assessment of heavy metals in surface sediments of the Luanhe River Estuary, northwest of the Bohai Sea النص الكامل
2016
Liu, Jinqing | Yin, Ping | Chen, Bin | Gao, Fei | Song, Hongying | Li, Meina
33 surface sediment samples from the Luanhe River Estuary have been analyzed for heavy metals to evaluate the spatial distribution pattern and their potential ecological risk. Higher metal concentrations were found in the river mouth and southern areas where being covered by fine particulate matters. In comparison with the threshold effect level and the probable effect level, Cu, Pb, Cr, Ni, and As had occasionally adverse biological effects on the aquatic ecosystems. Both the enrichment factor and geoaccumulation index values show that all the regions have been weakly polluted by Pb, Hg, As, and Cd with an exception of being moderately to strongly polluted by Hg in the river mouth and southern areas. The sources of Zn, Ni, Cd, Hg, and Cr were mainly from the river input and coastal discharge, whereas Cu, Pb, and As were mainly derived from vehicle emissions, coal and oil combustion.
اظهر المزيد [+] اقل [-]The role of social marketing, marine turtles and sustainable tourism in reducing plastic pollution النص الكامل
2016
Eagle, Lynne | Hamann, Mark | Low, David R.
Environmental plastic pollution constitutes a significant hazard to marine turtles, human health and well-being. We describe a transdisciplinary approach to draw together findings from diverse disciplines in order to highlight key environmental pollution problems and their consequences, together with social marketing-based strategies to address the problems. The example of plastic pollution and impacts to marine turtles illustrates the severity of the problem. Wildlife tourism and sustainable tourism activity have not focussed on specific behaviours to change and have had minimal impact on subsequent human behaviour regarding environmental issues, indicating the need for new strategies. Social marketing principles offer promise, but there is a need to investigate the utility of various theoretical foundations to aid the design and implementation of interventions. We offer insight towards using sophisticated multi-method research to develop insights into behaviours and segmentation-based strategies, that can aid the identification of barriers to, and enablers of, sustained behaviour change.
اظهر المزيد [+] اقل [-]Effect of nutrient enrichment on the source and composition of sediment organic carbon in tropical seagrass beds in the South China Sea النص الكامل
2016
Liu, Songlin | Jiang, Zhijian | Zhang, Jingping | Wu, Yunchao | Lian, Zhonglian | Huang, Xiaoping
To assess the effect of nutrient enrichment on the source and composition of sediment organic carbon (SOC) beneath Thalassia hemprichii and Enhalus acoroides in tropical seagrass beds, Xincun Bay, South China Sea, intertidal sediment, primary producers, and seawater samples were collected. No significant differences on sediment δ13C, SOC, and microbial biomass carbon (MBC) were observed between T. hemprichii and E. acoroides. SOC was mainly of autochthonous origin, while the contribution of seagrass to SOC was less than that of suspended particulate organic matter, macroalgae and epiphytes. High nutrient concentrations contributed substantially to SOC of seagrass, macroalgae, and epiphytes. The SOC, MBC, and MBC/SOC ratio in the nearest transect to fish farming were the highest. This suggested a more labile composition of SOC and shorter turnover times in higher nutrient regions. Therefore, the research indicates that nutrient enrichment could enhance plant-derived contributions to SOC and microbial use efficiency.
اظهر المزيد [+] اقل [-]Marine environmental protection: An application of the nanometer photo catalyst method on decomposition of benzene النص الكامل
2016
Lin, Mu-Chien | Kao, Jui-Chung
Bioremediation is currently extensively employed in the elimination of coastal oil pollution, but it is not very effective as the process takes several months to degrade oil.Among the components of oil, benzene degradation is difficult due to its stable characteristics. This paper describes an experimental study on the decomposition of benzene by titanium dioxide (TiO2) nanometer photocatalysis. The photocatalyst is illuminated with 360-nm ultraviolet light for generation of peroxide ions. This results in complete decomposition of benzene, thus yielding CO2 and H2O. In this study, a nonwoven fabric is coated with the photocatalyst and benzene. Using the Double-Shot Py–GC system on the residual component, complete decomposition of the benzene was verified by 4h of exposure to ultraviolet light. The method proposed in this study can be directly applied to elimination of marine oil pollution. Further studies will be conducted on coastal oil pollution in situ.
اظهر المزيد [+] اقل [-]Mobile monitoring of particulate matter: State of art and perspectives النص الكامل
2016
Gozzi, Fernando | Della Ventura, Giancarlo | Marcelli, A.
Due to the socio-economic impact and the consequences on human health, the pollution associated to Particulate Matter (PM) represents one of the main emergences at a global scale. For these reasons, in the last decade we assisted to a continuously increasing interest in the mobile monitoring of PM on a regional and a local scale. Here we summarize the current status in this field, outlining the critical issues and the perspectives. The growing availability of instruments designed and optimized to the real-time monitoring of the air quality, considerably increased the spatial and temporal resolution of available datasets, actually improving air pollution maps and forecast models. However, several issues are still unresolved, particularly in terms of data representativeness. Indeed, the future PM monitoring devices have to be designed to support the decisional process but also the management of environmental emergencies in urban and industrial areas. The future of these devices is certainly the development of compact systems that will make possible a real-time characterization of size distribution, morphology, and chemical composition of the airborne particles.
اظهر المزيد [+] اقل [-]Spatial variation and provenance of atmospheric trace elemental deposition in Beijing النص الكامل
2016
Zheng, Xiaoxia | Guo, Xiaoyu | Zhao, Wenji | Shu, Tongtong | Xin, Yanan | Yan, Xing | Xiong, Qiulin | Chen, Fantao | Lv, Ming
Atmospheric dry deposition samples were collected in urban and suburban areas of Beijing during a coal-burning period. Chemical characteristics of lanthanoid elements (La–Lu) and five heavy metals (Cr, Co, Mo, Cd, and Pb) were analyzed to determine the variation in spatial scale and deposition provenances. Factor analysis and ternary diagrams were used to identify principle pollution sources. The LaCeSm ternary diagram was used to identify oil refineries using fluid catalytic converters and steel plants, but could not differentiate crustal materials. Lanthanoid characteristic parameters showed similarity between deposition and soil in the local and southwest area in the vicinity of Beijing. Analysis of the five heavy metals enabled discrimination of contaminants originating from human activities. Cd, Pb, and Mo were found to originate from vehicular traffic, whereas Co and Cr originated from industrial emissions and coal combustion. Discriminant analysis established the causes of spatial variation. The result shows that Co, Mo, and Pb can mark the differences between urban and suburban sites. From the PbMoCo plot, it was inferred that the different chemical characters are mainly due to the differing origins of depositions. Deposition samples in suburban areas are principally influenced by soil, chimney soot, and fertilizer, whereas those in urban area are mainly affected by traffic emissions.
اظهر المزيد [+] اقل [-]Determination of ambient air concentrations and personal exposure risk levels of outdoor workers to carbonyl compounds and BTEX in the inner city of Bangkok, Thailand النص الكامل
2016
Kanjanasiranont, Navaporn | Prueksasit, Tassanee | Morknoy, Daisy | Tunsaringkarn, Tanasorn | Sematong, Saowanee | Siriwong, Wattasit | Zapaung, Kalaya | Rungsiyothin, Anusorn
The ambient and personal air concentrations of benzene, toluene, ethylbenzene and xylenes (BTEX) and carbonyl compounds (CCs) were investigated in Pathumwan district, Bangkok (Thailand), a congested area with a high level of traffic-related air pollution. The potential health risk of three representative groups of street workers (street vendors, motorcycle taxi driver and security guards) exposed to these substances was estimated. The personal air exposure and ambient air samples were collected in the rainy (September 2012) and summer (March 2013) seasons. The 8-h average formaldehyde and acetaldehyde exposure levels for both personal and ambient air concentrations were found to be the major CCs. The highest mean ambient air level of formaldehyde (20.1 μg/m3) was found at the roadside at a busy intersection next to department stores. The highest level of acetaldehyde (9.17 μg/m3) was found in a location with a high traffic load close to the hospital and university. For BTEX, the greatest average concentration was observed around the site located near a bus stop (45.5 μg/m3). In terms of the personal exposure concentrations of CCs and BTEX, no statistically significant differences were found among all sampled locations for street vendors and motorcycle taxi drivers. With respect to the health risk assessment, at a 95% confidence interval (CI) of cancer risk, benzene posed the highest risk followed by formaldehyde and then acetaldehyde (5.36E-06–1.48E-05, 5.58E-06–1.91E-05 and 1.03E-05–5.93E-05 for street vendors, motorcycle taxi driver and security guards) while the 95% CI non-cancer risk values were at an acceptable level. Nevertheless, there were no significant differences in the total cancer risk among the different groups of workers. From the health risk assessment, benzene and formaldehyde were the major traffic related air pollutants that likely affected the human health in this area.
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