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Результаты 971-980 из 3,243
Heavy metal pollution assessment in relation to sediment properties in the coastal sediments of the southern Caspian Sea
2015
Bastami, Kazem Darvish | Neyestani, Mahmoud Reza | Shemirani, Farzaneh | Soltani, Farzaneh | Haghparast, Sarah | Akbari, Atefeh
This study aimed to evaluate major elements and heavy metal concentrations of Arsenic (As), Copper (Cu), Chromium (Cr), Cobalt (Co), Vanadium (V), Nickel (Ni), lead (Pb) and Zinc (Zn) in surface sediments of the southern Caspian Sea. Metal contents in the sediment were observed in the order of: V>Cr>Zn>Ni>Co>Cu>Pb>As. Correlations between elements showed that sediment TOM, grain size and chemical composition are the main factors that influence the distribution of heavy metals. According to the pollution load index (PLI), sediments from some sampling sites were polluted. Concentrations of Ni, As, Cr and Cu were higher than sediment quality guidelines at some sampling sites, implying potential adverse impacts of these metals.
Показать больше [+] Меньше [-]Source apportionment of carbonaceous fine particulate matter (PM2.5) in two contrasting cities across the Indo–Gangetic Plain
2015
Villalobos, Ana M. | Amonov, Mansur O. | Shafer, Martin M. | Devi, J Jai | Gupta, Tarun | Tripathi, Sachi N. | Rana, Kushal S. | McKenzie, Michael | Bergin, Mike H. | Schauer, James J.
Agra and Kanpur are heavily polluted Indian cities and are the fourth and second largest cities in Uttar Pradesh State, respectively. PM2.5 was collected from December 2011 to May 2012 in Agra and from December 2011 to October 2012 in Kanpur every 6th day. The samples were chemically analyzed to determine organic carbon (OC), water soluble organic carbon (WSOC), elemental carbon (EC), secondary inorganic ions, and particle–phase organic compounds. A chemical mass balance (CMB) receptor model using organic tracers was used to estimate source contributions to PM2.5. Concentrations of carbonaceous aerosols were on average 23±16μg/m3 in Agra and 33±21μg/m3 in Kanpur during the winter and summer periods, and had a strong seasonal trend with highest levels in winter (December–February) and then decreasing to summer (March–May). Five primary sources were identified. In Agra, biomass burning was the major source of OC in the winter months with decreasing relative and absolute concentrations in summer. In Kanpur, biomass burning was also the most important primary source of OC, but was about half the concentration found in Agra. Mobile source contributions to OC were on average 25±9% and 25±22% in Agra and Kanpur, respectively, with similar absolute concentrations of 2.5±1.9μg/m3 in most months. Secondary organic aerosol (SOA) was estimated from non–biomass burning WSOC and the unapportioned OC, with each method indicating SOA as a major source of OC in the winter in both cities, apportioning 25% of OC in Agra and 65% in Kanpur. SOA in Kanpur in December was four times higher than in Agra. Overall, results suggest differences in aerosol chemical composition and sources at these two sites across the Indo–Gangetic plain with biomass burning making up a larger fraction of the particulate OC in Agra, and SOA being a more important contributor to OC mass in Kanpur.
Показать больше [+] Меньше [-]Current air quality plans in Europe designed to support air quality management policies
2015
Miranda, Ana | Silveira, Carlos | Ferreira, Joana | Monteiro, Alexandra | Lopes, Diogo | Relvas, Helder | Borrego, C. | Roebeling, Peter
The intensification of the human activity in urban areas as a result of the increasing population has contributed to the air pollution worsening in cities. To reverse this trend, the European Commission established a legal framework to improve the air quality. Thereby the Member States need to develop air quality plans (AQP) for zones and agglomerations where air quality limit values are exceeded, in order to implement pollution control strategies and meet the legal requirements. Understanding the reasons for the levels of air quality non–compliance as well as evaluating available and commonly used tools to predict the air quality and their effects, is crucial for the decision–making process on air quality management policies. Based on a compilation of regional and local AQP, a review of assessment capabilities and used modeling tools to evaluate the effects of emission abatement measures on the air quality and health was performed. In most cases, models are applied to estimate emissions and to assess the resulting air quality from both reference and emission abatement scenarios. Air quality’s impacts on the health and environment are rarely quantified. Regarding the air quality assessment, beyond the modeling, monitored data for validation of simulations are also used. Some studies, however, do not include the use of air quality models, considering the monitoring network as spatially representative of the study domain (e.g. Lisbon Region, Riga, Malta). In order to overcome methodological limitations for quantifying the impacts of emission abatement measures, economic evaluation techniques or even Integrated Assessment Methodologies (IAM) have been developed. IAM, already applied in some AQP or case studies, namely for Antwerp and London, are used for assessing how reductions in emissions contribute to improve air quality, reduce exposure and protect human health.
Показать больше [+] Меньше [-]Atmospheric levels and health risk of polycyclic aromatic hydrocarbons (PAHs) bound to PM2.5 in Guangzhou, China
2015
Liu, Jingjing | Man, Ruilin | Ma, Shexia | Li, Juansheng | Wu, Qi | Peng, Juanying
The polycyclic aromatic hydrocarbons (PAHs) in PM2.5 contribute significantly to health risk. The objectives of this study were to assess the occurrence and variation in the concentrations and sources of PM2.5-bound PAHs sampled from the atmosphere of a typical southeastern Chinese city (Guangzhou) from June 2012 to May 2013, with the potential risks being investigated. The annual average concentration of PM2.5 was 64.88μgm−3. The annual average concentration of PAHs in PM2.5 was 33.89ngm−3. Benzo(a)pyrene (BaP) was found to be the predominant PAH in all PM2.5 samples throughout the year, constituting approximately 8.78% of the total PAH content. The significant meteorological parameters for most of the PAHs were sunshine time, air pressure, and humidity, together representing 10.7–52.4% of the variance in atmospheric PAH concentrations. Motor-vehicle exhaust and coal combustion were probably the main sources of PAHs in PM2.5 in Guangzhou. The average inhalation cancer risk (ICR) for a lifetime of 70years was 5.98×10−4 (ranging from 8.39×10−5 to 1.95×10−3).
Показать больше [+] Меньше [-]Marine governance in the English Channel (La Manche): Linking science and management
2015
Glegg, G. | Jefferson, R. | Fletcher, S.
The English Channel is one of the world’s busiest sea areas with intense shipping and port activity juxtaposed with recreation, communications and important conservation areas. Opportunities for marine renewable energy vie with existing activities for space. The current governance of the English Channel is reviewed and found to lack integration between countries, sectors, legislation and scientific research. Recent developments within the EU’s marine management frameworks are significantly altering our approach to marine governance and this paper explores the implications of these new approaches to management of the English Channel. Existing mechanisms for cross-Channel science and potential benefits of an English Channel scale perspective are considered. In conclusion, current management practices are considered against the 12 Malawi Principles of the ecosystem approach resulting in proposals for enhancing governance of the region through science at the scale of the English Channel.
Показать больше [+] Меньше [-]Recovery of a subtropical rocky shore is not yet complete, four years after a moderate sized oil spill
2015
Finlayson, Kimberly | Stevens, Tim | Arthur, James Michael | Rissik, David
Little is known about the recovery trajectory from small to moderate spills (<1000t), particularly in the sub-tropics. On 11 March 2009 the MV Pacific Adventurer spilt 270t of bunker fuel oil 13km off Moreton Island, Australia, impacting wetlands, sandy beaches and rocky shores. This study examines the recovery of the rocky shore community four years after the spill. Results indicate that recovery on Moreton Island is taking longer than the 3–4years suggested by the literature. The upper shore is recovering faster than the mid shore and is nearly recovered while the mid shore is still in the recovery process. These results indicate that small to moderate sized spills can have environmental impacts on par with much larger spills and emphasizes the need for a clear definition of a recovery endpoint. Long term studies are required to gain a full understanding of trajectories of recovery after oil spill impacts.
Показать больше [+] Меньше [-]Selective extraction and concentration of mebendazole in seawater samples using molecularly imprinted polymer as sorbent
2015
Lian, Ziru | Liang, Zhenlin | Wang, Jiangtao
A high selective pre-treatment method for the extraction and analysis of mebendazole in environmental water samples was developed based on molecularly imprinted solid-phase extraction (MISPE). The mebendazole imprinted polymers were synthesized in acetonitrile using methacrylic acid and ethylene glycol dimethacrylate as functional monomer and cross-linker respectively. The imprinted materials showed high adsorption ability for mebendazole and were applied as special solid-phase extraction sorbents for selective separation of mebendazole. An off-line MISPE procedure was developed for the purification and enrichment of mebendazole from natural seawater samples prior to high-performance liquid chromatography analysis. The recoveries of spiked seawater on the MISPE cartridges were from 83.0% to 90.6%, and the values of the relative standard deviation were in the range of 2.78–4.13% (n=3). The satisfied results showed that this pre-treatment methodology for extracting mebendazole in seawater was simple and effective.
Показать больше [+] Меньше [-]Failure of the public health testing program for ballast water treatment systems
2015
Cohen, Andrew N. | Dobbs, Fred C.
Since 2004, an international testing program has certified 53 shipboard treatment systems as meeting ballast water discharge standards, including limits on certain microbes to prevent the spread of human pathogens. We determined how frequently certification tests failed a minimum requirement for a meaningful evaluation, that the concentration of microbes in the untreated (control) discharge must exceed the regulatory limit for treated discharges. In 95% of cases where the result was accepted as evidence that the treatment system reduced microbes to below the regulatory limit, the discharge met the limit even without treatment. This shows that the certification program for ballast water treatment systems is dysfunctional in protecting human health. In nearly all cases, the treatment systems would have equally well “passed” these tests even if they had never been turned on. Protocols must require minimum concentrations of targeted microbes in test waters, reflecting the upper range of concentrations in waters where ships operate.
Показать больше [+] Меньше [-]Sewage contamination in a tropical coastal area (São Sebastião Channel, SP, Brazil)
2015
Muniz, P. | da Silva, D.A.M. | Bícego, M.C. | Bromberg, S. | Pires-Vanin, A.M.S.
Urban effluent discharges in Brazilian coastal areas are a chronic problem and often lead to changes in the quality of the marine environment. São-Sebastião-Channel (SSC) is an important aquatic ecosystem to be monitored for urban sewage contamination due to the intense urban activities in that region, as well as the relative high biodiversity of marine organisms. In the area are present three submarine sewage outfalls, a commercial harbour and also the biggest oil terminal in Brazil. Total organic carbon (TOC), total nitrogen (TN), total sulphur (TS), steroids and linear alkylbenzenes (LABs) were measured in sediment samples collected in three strategic locations of the SSC in order to monitor urban sewage contamination. Total LAB and total sterols levels ranged from below DL–51.3ngg−1 and below DL–10.40μgg−1, respectively. Samples collected near sewage outfall in the central part of the SSC had higher concentrations of urban sewage-associated contaminants.
Показать больше [+] Меньше [-]Quantitative distribution and functional groups of intertidal macrofaunal assemblages in Fildes Peninsula, King George Island, South Shetland Islands, Southern Ocean
2015
Liu, Xiaoshou | Wang, Lu | Li, Shuai | Huo, Yuanzi | He, Peimin | Zhang, Zhinan
To evaluate spatial distribution pattern of intertidal macrofauna, quantitative investigation was performed in January to February, 2013 around Fildes Peninsula, King George Island, South Shetland Islands. A total of 34 species were identified, which were dominated by Mollusca, Annelida and Arthropoda. CLUSTER analysis showed that macrofaunal assemblages at sand-bottom sites belonged to one group, which was dominated by Lumbricillus sp. and Kidderia subquadrata. Macrofaunal assemblages at gravel-bottom sites were divided into three groups while Nacella concinna was the dominant species at most sites. The highest values of biomass and Shannon–Wiener diversity index were found in gravel sediment and the highest value of abundance was in sand sediment of eastern coast. In terms of functional group, detritivorous and planktophagous groups had the highest values of abundance and biomass, respectively. Correlation analysis showed that macrofaunal abundance and biomass had significant positive correlations with contents of sediment chlorophyll a, phaeophorbide and organic matter.
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