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Resultados 1421-1430 de 4,042
Urban air quality evaluations under two versions of the national ambient air quality standards of China Texto completo
2016
Chen, Wei | Tang, Hongzhao | Zhao, Haimeng
The air quality of urban areas is of a great concern for residents living in cities. China has released a new National Ambient Air Quality Standard (NAAQS) in 2012 to improve the air quality evaluation index because the reported air quality situation from governments is inconsistent with public sensing. In total, 190 cities' hourly monitoring data are publicized in the national web platform. By using the above data, the air pollution indexes (APIs) under the previous NAAQS and air quality indexes (AQI) for all 190 cities' were calculated. With the new NAAQS, the national attainment rate has fallen from 73.63% to 59.62% with regional differences. 8 of the 10 cities with the worst air quality are located in North China around Beijing, while 9 of the 10 cities with the best air quality are located in South China. These results indicate that cities in North China, including Beijing, need to address the air pollution together as the pollution in North China is a regional issue and not a local issue.
Mostrar más [+] Menos [-]Assessment of heavy metal contamination in surface sediments of the west Guangdong coastal region, China Texto completo
2016
Zhao, Guangming | Lu, Qingyuan | Ye, Siyuan | Yuan, Hongming | Ding, Xigui | Wang, Jin
Heavy metals (As, Cd, Cr, Cu, Hg, Pb, Zn), organic carbon and grain size of 237 surface sediment samples and one sediment core, taken from the west Guangdong coastal region in January 2008, were analyzed to evaluate the spatial distribution and pollution status. Results show that the ranges of the measured heavy metal concentrations in sediments are as follows: 8.33–39.49mg/kg for As, 0.1–1.49mg/kg for Cd, 33–108mg/kg for Cr, 11.5–78.8mg/kg for Cu, 0.04–0.26mg/kg for Hg, 21–73mg/kg for Pb, 56–248mg/kg for Zn. The heavy metal enrichment is closely associated with Corg and grain size. Both the metal enrichment factor and geoaccumulation index indicate that there was no detected pollution on metals As, Cr, Cu, Pb in our study area and a slight to moderate contamination of Cd, Hg and Zn. However, As, Cr and Cu have showed a certain risk.
Mostrar más [+] Menos [-]Collaboration between central and state government and environmental quality: Evidences from Indian cities Texto completo
2016
Sinha, Avik | Rastogi, Siddhartha K.
Within the context of coordination level between state and central government, we develop an econometric model to estimate the association between income and ambient air pollution, considering the societal preferences jointly influenced by the citizens and the government. We obtain empirical evidence supporting our hypothesis that state level coalition government can effectively improve quality of environment by means of reducing ambient air pollution level. This impact can be increased or decreased based on the societal preferences of the citizens, based on the area of inhabitance and irrespective of the choice of pollutants.
Mostrar más [+] Menos [-]Contribution of fungal spores to organic carbon in ambient aerosols in Beijing, China Texto completo
2016
Liang, Linlin | Engling, Guenter | Du, Zhenyu | Duan, Fengkui | Cheng, Yuan | Liu, Xuyan | He, Kebin
Fungal spores are ubiquitous components of atmospheric aerosols and contributors to the organic carbon (OC) component in ambient aerosols. In order to better understand the role of fungal spores and their impact on atmospheric processes, this study was conducted to investigate the contribution of fungal spores to OC at urban and rural sites in Beijing, China. Ambient concentrations of a molecular tracer for fungal spores, i.e., mannitol in PM10 and PM2.5 samples were measured at an urban site (Tsinghua University, THU) during an entire year, while the observations in PM10 at a rural site (Miyun, MY) were conducted during late spring and summer. Combined with the factor representing the average content of mannitol per spore (0.49 ± 0.20 pg) obtained at the same urban site in Beijing, the year-round number concentrations of fungal spores were obtained. Using a conversion factor of 13 pg C spore−1, the annual average concentrations of spore-OC in PM2.5 and PM10 at the THU site were observed at 0.3 ± 0.2 μgC m−3 and 0.8 ± 0.7 μgC m−3, while the respective contributions of spore-OC to total OC were 1.2 ± 0.7% and 3.5 ± 3.7%, respectively. The contributions of fungal spores to OC in the two size fractions had the following seasonal trend (from highest to the lowest levels): summer, autumn, winter and spring. During the summer sampling season, the contribution of fungal spores to OC was observed at a higher level at the rural site (14.1 ± 10.5%), compared to the urban site (7.3 ± 3.3%). It can be concluded that fungi are a non-negligible source of carbonaceous aerosol even at urban locations such as Beijing, China. Thus, more studies are needed to better understand the spatial, temporal and size distributions of fungal OC contributions to atmospheric aerosols in populated areas.
Mostrar más [+] Menos [-]Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia Texto completo
2016
van der Wulp, Simon A. | Damar, Ario | Ladwig, Norbert | Hesse, Karl-J.
The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m3s−1 entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics.
Mostrar más [+] Menos [-]Evaluation of anthropogenic contamination using sterol markers in a tropical estuarine system of northeast Brazil Texto completo
2016
Frena, Morgana | Souza, Michel R.R. | Damasceno, Flaviana C. | Madureira, Luiz A.S. | Alexandre, Marcelo R.
The São Francisco River estuarine system, located in the Northeast coast of Brazil, has great economic, tourist and social importance. Its waters are used for activities such as agriculture, aquaculture, navigation and fishery, which supplies the surrounding communities. In this study, sterols markers were determined in twenty-eight sediment samples from São Francisco River estuary by gas chromatography - mass spectrometry (GC–MS). Sterol analysis was useful to distinguish between anthropogenic and biogenic organic matter (OM) sources in the studied area. Six sterols were quantified, suggesting different sources. Concentrations of fecal sterol (coprostanol) were lower than 500ngg−1, suggesting no indicative of severe sewage contamination.However, two stations showed concentrations around 100ngg−1 and the values for the coprostanol/(coprostanol+cholestanol) and coprostanol/cholesterol ratios indicates sewage contamination. The results in this study may be considered as baseline concentrations to be used as future reference for monitoring programs to prevent anthropogenic impacts.
Mostrar más [+] Menos [-]Assessing the progress in depolluting the Mediterranean Sea Texto completo
2016
Spiteri, Claudette | Roddier-Quefelec, Cécile | Giraud, Jean-Pierre | Hema, Tatiana
The depollution of the Mediterranean Sea by 2020 is the overarching goal of Horizon 2020 Initiative (H2020). The first phase (2007–2013) tackled the main land-based pollution sources; municipal waste, urban wastewater and industrial emissions. As part of the H2020 roadmap implementation, the ENPI-SEIS project focused on the first H2020 review mechanism that included a) establishing a process for regular environmental reporting in the European Neighbourhood Policy South countries, and b) generating the knowledge necessary to assess the progress in depolluting the Mediterranean Sea. This paper reviews the process in line with the “Shared Environmental Information System” principles and its three pillars (content, cooperation, infrastructure). The main outcomes of the thematic assessment, based on a set of regional H2020 indicators, are also presented. This assessment highlights the major drivers and their implications on marine protection. It also identifies areas that require further attention in the next phase of H2020 (2014–2020).
Mostrar más [+] Menos [-]Host condition and accumulation of metals by acanthocephalan parasite Echinorhynchus gadi in cod Gadus morhua from the southern Baltic Sea Texto completo
2016
Podolska, M. | Polak-Juszczak, L. | Nadolna-Ałtyn, K.
In this study, we analyzed the relationship between concentration of metals in the host-parasite system (cod - acanthocephalan Echinorhynchus gadi) and Fulton's condition factor (FCF) of the host. The relationship between metal (Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Pb, Sr, Zn) concentrations in E. gadi and cod tissues was expressed as a bioconcentration factor (BCF), the ratio of the concentration in the parasite tissue to that in host tissues. Acanthocephalans accumulated mainly toxic metals (Cd, Pb), as well as Sr, Ca, Na. Cadmium showed the highest bioconcentration in parasites (BCF >200) compared to fish muscle. Significant negative correlation was detected between FCF and the concentration of Cd and Hg in cod liver. In contrast, FCF was positively correlated with the concentration of Hg in acanthocephalan tissues.
Mostrar más [+] Menos [-]Growth effects of shading and sedimentation in two tropical seagrass species: Implications for port management and impact assessment Texto completo
2016
Benham, Claudia F. | Beavis, Sara G. | Hendry, Rebecca A. | Jackson, Emma L.
Seagrass meadows in many parts of the globe are threatened by a range of processes including port development, dredging and land clearing in coastal catchments, which can reduce water clarity and increase sedimentation pressure. As rates of seagrass loss increase, there is an urgent need to understand the potential impacts of development on these critical species. This research compares the effects of shading and burial by fine sand on two seagrass species Zostera muelleri and Halophila ovalis in Port Curtis Bay, an industrial harbour located on the continental margin adjacent to the Great Barrier Reef Heritage Area, Australia. The research finds that shading in combination with burial causes a significant decline in growth rates in both species, but that burial ≥10mm reduces growth rates to a greater extent than shading. The paper concludes by discussing the implications of these findings for port management and impact assessment.
Mostrar más [+] Menos [-]The changing dynamics of coral reef science in Arabia Texto completo
2016
Vaughan, Grace O. | Burt, John A.
Six percent of the world's coral reefs occur around the Arabian Peninsula, providing a valuable ecological, economic and scientific resource for the nations bordering its shores. We provide the first region-wide assessment of the current status and historical trends in coral reef research, focusing on research in the Red Sea, Arabian Sea, and Arabian Gulf. In total, 633 regional reef publications have been produced since the 1930s, covering a wide variety of themes and taxa. Our results show a great deal of commonality in regional reef research, but also highlight important differences in research among the various seas as well as knowledge gaps that represent opportunities for future research. A regionally-integrated approach to future research is essential. There is a growing need for large-scale research to guide management of reefs and their stressors, as these operate at much larger scales than the national borders within which most research currently occurs.
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