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Distribution of Alexandrium fundyense and A. pacificum (Dinophyceae) in the Yellow Sea and Bohai Sea 全文
2015
Gao, Yan | Yu, Ren-Cheng | Chen, Jian-Hua | Zhang, Qing-Chun | Kong, Fan-Zhou | Zhou, Ming-Jiang
This study characterizes the distribution of two closely related, causative species of paralytic shellfish poisoning – Alexandrium fundyense and A. pacificum – within the Yellow Sea (YS) and Bohai Sea (BS). These two Alexandrium species are distinguished for the first time in a regional field study using species-specific, quantitative PCR (qPCR) based assays. Both qPCR assays target the large subunit ribosomal DNA gene and were used to analyze net-concentrated phytoplankton samples collected in May 2012. A. fundyense was mainly distributed in YS, while A. pacificum was confined to an area adjacent to the Changjiang River estuary. The different distribution of the two species is interpreted as evidence of their distinct bloom ecology. Expanded efforts implementing these assays offer the ability to discriminate the dynamics of A. fundyense and A. pacificum blooms and provide a more sound basis for monitoring toxic Alexandrium species in this region.
显示更多 [+] 显示较少 [-]Pb, Cu and Cd distribution in five estuary systems of Marche, central Italy 全文
2015
Annibaldi, Anna | Illuminati, Silvia | Truzzi, Cristina | Libani, Giulia | Scarponi, Giuseppe
Heavy metals are subjected to monitoring in estuarine and marine water by the European Union Water Framework Directive, which requires water body health to be achieved by 2021. This is the first survey of heavy metals content in five estuaries of Marche, a region in central Italy. Results showed that total Pb and Cu concentrations decreased by 70–80%, from 1000–2000 to 100–200ngL−1 (Pb) and from 2000–3000 to 500–1000ngL−1 (Cu) from river to sea. Cd was consistently 20–40ngL−1. Dissolved Pb and Cu concentrations declined by 50% and 70% respectively passing from oligohaline to euhaline water, from 150 to 70ngL−1 and from 2000–1000 to 600–400ngL−1. Cd decreased slightly from ∼20 to ∼10ngL−1. Although such concentrations are in the range allowed by the Water Framework Directive, they far exceed (up to 10×) the ground content ceiling set for 2021.
显示更多 [+] 显示较少 [-]Marine litter in the upper São Vicente submarine canyon (SW Portugal): Abundance, distribution, composition and fauna interactions 全文
2015
Oliveira, Frederico César Barbosa de | Monteiro, Pedro | Bentes, Luis | Henriques, Nuno Sales | Aguilar Melantzón, Ricardo | Gonçalves, Jorge M.S.
Marine litter has become a worldwide environmental problem, tainting all ocean habitats. The abundance, distribution and composition of litter and its interactions with fauna were evaluated in the upper S. Vicente canyon using video images from 3 remote operated vehicle exploratory dives. Litter was present in all dives and the abundance was as high as 3.31 items100m−1. Mean abundance of litter over rock bottom was higher than on soft substrate. Mean litter abundance was slightly higher than reported for other canyons on the Portuguese margin, but lower in comparison to more urbanized coastal areas of the world. Lost fishing gear was the prevalent type of litter, indicating that the majority of litter originates from maritime sources, mainly fishing activity. Physical contact with sessile fauna and entanglement of specimens were the major impacts of lost fishing gear. Based on the importance of this region for the local fishermen, litter abundance is expected to increase.
显示更多 [+] 显示较少 [-]Spatial distribution and sources of heavy metals and petroleum hydrocarbon in the sand flats of Shuangtaizi Estuary, Bohai Sea of China 全文
2015
Yang, Xiaolong | Yuan, Xiutang | Zhang, Anguo | Mao, Yuze | Li, Qiang | Zong, Humin | Wang, Lijun | Li, Xiaodong
The concentrations of heavy metals and petroleum hydrocarbons (PHCs) in surface sediments were investigated in the sand flats of Shuangtaizi Estuary, Bohai Sea of China in May, 2013. Ecological risk assessment indicated that most heavy metals cause low ecological risk to the estuarine environment, with the exception of Cd and Hg (considerable and moderate risk, respectively). Principal component analysis in combination with correlation analysis among heavy metals, PHCs and geological factors (e.g., granularity) was used to identify possible sources of pollutants in Shuangtaizi Estuary. Results showed that the main pollution sources of the area come from anthropogenic factors, such as sewage discharge and oil exploitation.
显示更多 [+] 显示较少 [-]Microwave assisted catalytic removal of elemental mercury from flue gas using Mn/zeolite catalyst 全文
2015
Wei, Zaishan | Luo, Yuwei | Li, Baoren | Cheng, Zhouyang | Wang, Jianbin | Ye, Qihong
The integrated microwave with Mn/zeolite and ozone (MCO) and combined microwave with Mn/zeolite (MC) was employed to oxidize elemental mercury (Hg0) in simulated flue gas. The results show that mercury removal efficiency attained 35.3% in the MC, over 92% of Hg0 removal efficiency could be obtained in the MCO. The optimal microwave power and empty bed residence time (EBRT) in the microwave plasma catalytic oxidation were 264 W and 0.41 s, respectively. The effect of Hg0 oxidation in the MCO was much higher than that in the MC. Microwave accentuated catalytic oxidation of mercury, and increased mercury removal efficiency. The additional use of ozone to the microwave–catalysis over Mn/zeolite led to the enhancement of mercury oxidation. Mn/zeolite catalyst was characterized by X–ray diffraction (XRD), X–ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT–IR), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic mercury over Mn/zeolite was dominated by a free radical oxidation route. Ozone molecules in air could enhance free radical formation. The coupling role between ozone and radicals on mercury oxidation in the MCO was formed. The MCO appears to be a promising method for emission control of elemental mercury.
显示更多 [+] 显示较少 [-]Relationship of MISR component AODs with black carbon and other ground monitored particulate matter composition 全文
2015
Zeeshan, Muhammad | Nguyễn, Thị Kim Oanh
This study assessed the relationship between the satellite Aerosol Optical Depths (AODs) and the ground monitored concentrations of particulate matter (PM) mass and its major constituents (black carbon–BC, organic carbon–OC, sulfates and nitrates), respectively. Both component AOD and total AOD products of Multi–angel Imaging Spectro Radiometer (MISR) were used for comparison along with the AOD product of the Moderate Resolution Imaging Spectroradiometer (MODIS). The ground PM data available during the period from 2004 to 2010 at the Asian Institute of Technology (AIT), a suburb site of the Bangkok Metropolitan Region, was used. MODIS and MISR AODs were validated against Sun photometer AOD, monitored at the Pimai AERONET station which showed strong linear regression with high R2 values of 0.87 and 0.92, respectively. The correlation coefficients between MODIS and MISR AODs and PM mass concentrations, respectively, were improved after exclusion of observations with cloud cover above 3/10. The R values (square root of determination coefficient R2) for linear relationships between PM10 and MODIS AOD were accordingly increased from 0.33 to 0.58 for MODIS AOD and from 0.25 to 0.54 for MISR AOD, while those for PM2.5 were improved from 0.30 to 0.55 for MODIS AOD and from 0.31 to 0.43 for MISR AOD. The stepwise regression was conducted to analyze the relationship between MISR component AODs and the mass concentration of PM10 and PM2.5, respectively, as well as their constituents. Higher R values were obtained for all regression equations using MISR component AODs as compared to those using total AOD. MISR component AODs showed higher capacity for monitoring daily BC (R=0.74–0.75) and sulfates (R=0.72), as compared to nitrates (R=0.52–0.54) and hourly OC (R=0.47). The potential of MISR component AODs for ambient PM monitoring should be explored and applied in other regions.
显示更多 [+] 显示较少 [-]Effect of rhamnolipid biosurfactant on solubilization of polycyclic aromatic hydrocarbons 全文
2015
Li, Shudong | Pi, Yongrui | Bao, Mutai | Zhang, Cong | Zhao, Dongwei | Li, Yiming | Sun, Peiyan | Lu, Jinren
Rhamnolipid biosurfactant-producing bacteria, Bacillus Lz-2, was isolated from oil polluted water collected from Dongying Shengli oilfield, China. The factors that influence PAH solubilization such as biosurfactant concentration, pH, ionic strength and temperature were discussed. The results showed that the solubilities of naphthalene, phenanthrene and pyrene increased linearly with the rise of rhamnolipid biosurfactant dose above the biosurfactant critical micelle concentration (CMC). Furthermore, the molar solubilization ratio (MSR) values decreased in the following order: naphthalene>phenanthrene>pyrene. However, the solubility percentage increased and followed the opposite order: pyrene>phenanthrene>naphthalene. The solubilities of PAHs in rhamnolipid biosurfactant solution increased with the rise of pH and ionic strength, and reached the maximum values under the conditions of pH11 and NaCl concentration 8g·L−1. The solubility of phenanthrene and pyrene increased with the rise of temperature.
显示更多 [+] 显示较少 [-]Assessing the ecological quality status of a temperate urban estuary by means of benthic biotic indices 全文
2015
Hutton, M. | Venturini, N. | García-Rodríguez, F. | Brugnoli, E. | Muniz, P.
Benthic indices are commonly used tools for assessing the environmental quality, because they represent a simple source of scientific information. However, their performance could vary depending on the application area and perturbation types, thus they should be tested before used in other remote geographic regions. This study aims to test the use of some of the most widely common benthic biotic indices for assessing the environmental quality of Montevideo’s coastal zone at a seasonal scale against many physicochemical variables. From all the evaluated indices, AMBI appears to be the most suitable one to assess the environmental quality. The study also allowed us to infer the most relevant physicochemical variables: protein, lipid and heavy metal sediment concentration. Additionally, site-specific threshold effect levels for heavy metals and biopolymers were established, which appear to be useful to determine tolerable levels of such stressors in future assessments or monitoring programs for the study area.
显示更多 [+] 显示较少 [-]Characterization and activity of N doped TiO2 supported VPO catalysts for NO oxidation 全文
2015
Jia, Yong | Du, Daqian | Bai, Jiachuan | Ding, Jie | Zhong, Qin | Ding, Xilou
Nitrogen (N) doped TiO2 supported vanadium phosphorus oxide (VPO) catalysts were prepared and tested for catalytic oxidation of NO. The experimental results showed that 0.1V(5)PO/TiN(1) was the optimal catalyst for NO oxidation and the NO conversion could reach 61% at temperature of 350°C. The physico–chemical properties of 0.1V(5)PO/TiN(1) catalyst were characterized by Brunauer–Emmett–Teller measurements (BET), Photoluminescence (PL), X–ray photoelectron spectroscopy (XPS), Infrared spectroscopy measurements of NH3 adsorbed on catalysts (NH3–IR), and Infrared Fourier transform spectroscopy (FTIR). The PL and XPS spectra revealed that the oxygen storage capacity and catalytic activity of VPO/Ti catalyst can be improved by nitrogen doping. The H2–TPR profile also indicated that V(5)PO/TiN(1) catalyst had a superior redox property. Activity test results and FTIR spectra showed that 0.1V(5)PO/TiN(1) catalysts had a superior resistivity to SO2 and the NO oxidation rate is above 50% at temperature of 350°C when SO2 concentration is 200ppm to 800ppm.
显示更多 [+] 显示较少 [-]Mercury concentrations in feathers of marine birds in Arctic Canada 全文
2015
Mallory, Mark L. | Braune, Birgit M. | Provencher, Jennifer F. | Callaghan, D Benjamin | Gilchrist, H Grant | Edmonds, Samuel T. | Allard, Karel | O’Driscoll, Nelson J.
Mercury (Hg) concentrations are a concern in the Canadian Arctic, because they are relatively high compared to background levels and to similar species farther south, and are increasing in many wildlife species. Among marine birds breeding in the Canadian Arctic, Hg concentrations have been monitored regularly in eggs and intermittently in livers, but feathers have generally not been used as an indicator of Hg exposure or burden. We examined Hg concentrations in six marine bird species in the Canadian Arctic. Ivory gull Pagophila eburnea, feather Hg was exceptionally high, while glaucous gull Larus hyperboreus feather Hg was unexpectedly low, and ratios of feather THg to egg THg varied across species. The proportion of total Hg that was comprised of methyl Hg in ivory gull feathers was lower than in other species, and may be related to photo-demethylation or keratin breakdown in semi-opaque feather tissue.
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