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Результаты 551-560 из 3,243
Brominated dioxin and furan stack gas emissions during different stages of the secondary copper smelting process
2015
Mei, Wang | Guorui, Liu | Xiaoxu, Jiang | Wenbin, Liu | Li, Li | Sumei, Li | Minghui, Zheng | Jiayu, Zhan
Secondary copper smelting processes (SeCu) have previously been identified as an important source of brominated dioxins and furans (PBDD/Fs). Identifying the major stages responsible for PBDD/F formation and emissions is crucial for developing technology to reduce PBDD/F emissions from SeCu, but nothing is currently known in this regard. In this study, stack gas samples from three smelting stages (feeding–fusion, oxidation and deoxidization) were collected and analyzed for PBDD/Fs to identify the stage most responsible for PBDD/F emissions. The results indicated that PBDD/F emissions mainly occurred during the feeding–fusion stage. Overall, PBDF emissions were much higher than PBDD emissions throughout the smelting process. Higher–brominated PBDD/F congeners were the most dominant contributors. The emission factors of PBDD/Fs during the feeding–fusion, oxidation and deoxidization stages were calculated to be 715, 119 and 31ng t−1, respectively. The results of this study are important for identifying the stages most responsible for PBDD/F emissions and developing techniques for reducing PBDD/F emissions from SeCu processes.
Показать больше [+] Меньше [-]Experimental assessment of critical anthropogenic sediment burial in eelgrass Zostera marina
2015
Munkes, Britta | Schubert, Philipp R. | Karez, Rolf | Reusch, Thorsten B.H.
Seagrass meadows, one of the world's most important and productive coastal habitats, are threatened by a range of anthropogenic actions. Burial of seagrass plants due to coastal activities is one important anthropogenic pressure leading to the decline of local populations. In our study, we assessed the response of eelgrass Zostera marina to sediment burial from physiological, morphological, and population parameters. In a full factorial field experiment, burial level (5–20cm) and burial duration (4–16weeks) were manipulated. Negative effects were visible even at the lowest burial level (5cm) and shortest duration (4weeks), with increasing effects over time and burial level. Buried seagrasses showed higher shoot mortality, delayed growth and flowering and lower carbohydrate storage. The observed effects will likely have an impact on next year's survival of buried plants. Our results have implications for the management of this important coastal plant.
Показать больше [+] Меньше [-]An assessment of human influences on sources of polycyclic aromatic hydrocarbons in the estuarine and coastal sediments of China
2015
Duan, Xiaoyong | Liu, Jinqing | Zhang, Daolai | Yin, Ping | Li, Yanxia | Li, Xianguo
Sediments collected from the coastal area of China, embracing west coast of Bohai Sea, south coast of Shandong Peninsula, and the Changjiang estuary (listed in order of decreasing north latitude), were analyzed for polycyclic aromatic hydrocarbons (PAHs). ∑PAH (Sixteen US EPA priority PAHs) were 2.7–350.9ng/g. Petroleum residue was the major contributor of PAHs in the coastal sediments of China due to oil leakage from ships and offshore oil fields. The contribution of vehicular emissions in coast of North China was significantly lower than that in the Changjiang Estuary, and the reverse was true for coal combustion. PAH concentrations in the sediment core of the Changjiang estuary steadily increased upward and the variation was primarily due to economic development and severe floods. The impact on PAHs by vehicular emissions (37.2%) and petrogenic sources (45.8%) overwhelmed combustion sources (17.0%).
Показать больше [+] Меньше [-]Illegal discharges in Spanish waters. Analysis of the profile of the Alleged Offending Vessel
2015
Martín Alonso, J.M. | Ortega Piris, Andrés | Pérez Labajos, Carlos
There is at present a growing concern, on an international level, over environmental offences caused by oil discharges into the sea from vessels. The objective of the Spanish Maritime Administration is to prevent the illegal discharges of polluting substances in Spanish maritime waters by vessels in transit. To combat such discharges, since 2007 Spain has reinforced its means of response with the use of aircrafts that provide services of maritime surveillance, identifying the Alleged Offending Vessels and acting as a deterrent.The objective of the present study is both to introduce the concept and to analyze certain aspects of the so-called “Alleged Offending Vessel” (AOV) that have been detected within Spanish Search and Rescue (SAR) jurisdiction waters in the period 2008–2012, in order to build a profile of such a vessel. For this purpose, an analysis methodology is formalized based on the GINI index and Lorenz curves, associated with certain aspects of vessels: type, flag and sailing area.
Показать больше [+] Меньше [-]Spatial distribution of some trace and major elements in sediments of the Cávado estuary (Esposende, Portugal)
2015
Gredilla, Ainara | Stoĭchev, Teodor | Fdez-Ortiz de Vallejuelo, Silvia | Rodriguez-Iruretagoiena, Azibar | de Morais, Paulo | Arana, Gorka | de Diego, Alberto | Madariaga, Juan Manuel
For the first time, the occurrence and spatial distribution of several elements, including some toxic metals, have been investigated in sediments of the estuary of the Cávado River (Esposende, Portugal). The pseudo total concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, V and Zn in sediments collected at 24 sites covering the tidal part of the estuary were determined. According to the concentrations measured, the Cávado estuary can be considered as non-contaminated. For most of the elements, the concentrations tended to be higher upstream. Only a moderate enrichment in Cr and Ni was detected in a few sites. An important decrease in concentration was observed for the most toxic metals compared to historical data reported in the literature. Several hotspots were identified, but even in those cases the amount of metals stored in the sediments does not represent a toxicological threat to living organisms.
Показать больше [+] Меньше [-]Occurrence and distribution of bisphenol A and alkylphenols in the water of the gulf of Gdansk (Southern Baltic)
2015
Staniszewska, Marta | Koniecko, Iga | Falkowska, Lucyna | Krzymyk, Ewelina
In 2011–2012, the concentrations of bisphenol A (BPA), 4-tert-octylophenol (OP) and 4-nonylphenol (NP) in surface and near-bottom water of the Gulf of Gdansk, as well as inflowing rivers, were similar to those in other regions of Europe; BPA from <5.0 to 277.9ngdm−3, OP from <1.0 to 834.5ngdm−3, and NP from <4.0 to 228.6ngdm−3. The atmospheric transportation of phenol derivatives and their deposition into the water of the gulf was indicated by high enrichment factor values (EF) in the sea surface microlayer in relation to the sub-surface layer.The main route of BPA, OP and NP transportation into the waters of the Gulf of Gdansk is the River Vistula. In spring, significant amounts of bisphenol A and 4-nonylphenol were introduced to the coastal zone with meltwater. The main factors affecting the variability of BPA, OP and NP concentrations in surface and near-bottom water, particularly in summer, were increased tourism in the coastal region, water temperature and dissolved oxygen concentration.
Показать больше [+] Меньше [-]Distribution and bioaccumulation of heavy metals in marine organisms in east and west Guangdong coastal regions, South China
2015
Zhang, Ling | Shi, Zhen | Jiang, Zhijian | Zhang, Jingping | Wang, Fei | Huang, Xiaoping
Heavy metal (Cu, Pb, Zn, Cr, Cd, As) concentrations, distribution and bioaccumulation were studied in marine organisms in Guangdong coastal regions. Heavy metal concentrations and distribution in organisms showed characteristics according to areas and species. Heavy metal concentrations in most organisms were higher in west than in east, tightly related to the local industry structure and the disequilibrium of metal discharge. Generally, high heavy metal concentrations were detected in molluscs and low concentrations were detected in fish. Bioaccumulation factor was used to assess the accumulation level of marine organisms to heavy metals, of which Cd, Cu and As were the most accumulated elements. Accumulation abilities to heavy metals varied among organism species, such as Distorsio reticulate accumulating Cu, Zn, Cd, As, Loligo beka Sasaki accumulating Pb, Cu, Cr, and Turritella bacillum Kiener accumulating Zn, Cd, As. By comparison, Johnius belengeri, Argyrosomus argentatus, Cynoglossus sinicus Wu had relatively low accumulation abilities.
Показать больше [+] Меньше [-]Porous membranes for ballast water treatment from microalgae-rich seawater
2015
Guilbaud, Julie | Massé, Anthony | Wolff, François-Charles | Jaouen, Pascal
The ballast waters from ships pose a major threat to oceans, notably because of the spread of microorganisms. The present study evaluates the techno-economic feasibility of implementing the membrane process to remove microalgae from seawater to be ballasted in a single step during planktonic bloom. The optimal conditions for the microfiltration of complex and reproducible synthetic seawater are a permeate flux and specific filtered volume of 100L.h−1.m−2 and 75L.m−2.cycle−1, respectively. Recovery of the membrane process represents about 76.6% and 62.7% of the annual cost for a cruise ship (5400 passengers) and liquefied natural gas (LNG) carrier (75,000m3 of liquid natural gas), followed by the membrane replacement cost (13.4% and 21.9%, respectively). The treatment costs are competitive with conventional treatments, even when the membrane process is more feasible for cruise ships due to its smaller capital cost and footprint.
Показать больше [+] Меньше [-]An effective seed protection method for planting Zostera marina (eelgrass) seeds: Implications for their large-scale restoration
2015
Zhang, Pei-Dong | Fang, Chao | Liu, Jie | Xu, Qiang | Li, Wen-Tao | Liu, Yan-Shan
We describe an innovative method of planting Zostera marina (eelgrass) seeds in which hessian bags filled with high-silted sediments are used as a seed protecting device. Here, we evaluated the effectiveness of the method through a field seed-sowing experiment over a three year period. The suitable seed planting density required by the seeds of Z. marina in this method was also investigated. In the spring following seed distribution, seedling establishment rate of Z. marina subjected to different seed densities of 200–500seedsbag−1 ranged from 16% to 26%. New eelgrass patches from seed were fully developed and well maintained after 2–3years following distribution. The seed planting density of 400seedsbag−1 may be the most suitable for the establishment of new eelgrass patches. Our results demonstrate that seed-based restoration can be an effective restoration tool and the technique presented should be considered for future large-scale Z. marina restoration projects.
Показать больше [+] Меньше [-]“Unresolved Complex Mixture” (UCM): A brief history of the term and moving beyond it
2015
Farrington, John W. | Quinn, James G.
The term “Unresolved Complex Mixture” (UCM) has been used extensively for decades to describe a gas chromatographic characteristic indicative of the presence of fossil fuel hydrocarbons (mainly petroleum hydrocarbons) in hydrocarbons isolated from aquatic samples. We chronicle the origin of the term. While it is still a useful characteristic for screening samples, more modern higher resolution two dimensional gas chromatography and gas chromatography coupled with advanced mass spectrometry techniques (Time-of-Flight or Fourier Transform-Ion Cyclotron Resonance) should be employed for analyses of petroleum contaminated samples. This will facilitate advances in understanding of the origins, fates and effects of petroleum compounds in aquatic environments.
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