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Diazo-coupling spectrophotometric determination of nitrogen oxides in the air 全文
2016
Huang, Yingying | Shi, Wenjian | Zhang, Caihong | Li, Liang | Wen, Haifeng
A new accurate, sensitive, rapid and convenient measurement for the determination of nitrogen oxides in the air was established. After being oxidized by chromium trioxide (CrO3), nitrogen oxides in the air existed in the form of NO2, then forming nitrite and nitrate after being absorbed by the alkaline aqueous solution. Under acidic condition, the diazo reaction is specific to the nitrite and primary aromatic amine. In this paper, the structure of diazo and coupling compounds were selected and tested through the experiments. The relationship between the azo compound's molecular structure and the sensitivity of the method as well as the electronic flow direction in the conjugated system of azo compounds were studied. A theory that conjugated system's electron cloud in azo compound's molecule flowed from coupling compounds to diazo compounds through nitrogen and nitrogen double bond was proposed. This theory had a guiding function for exploiting highly sensitive chromogenic agents. Furthermore, the conditions and methods of diazo reaction and coupling chromogenic reaction were investigated. A spectrophotometry that p-aminobenzenesulfonic acid as diazo compound and 2-amino-5-naphthol-7-sulfonic acid (J acid) as coupling compound for the determination of nitrogen oxides in the air was established. The maximum absorption wavelength of p-aminobenzenesulfonic acid-J acid azo compound was at 480 nm. And the molar absorptivity was 4.01 × 104 L mol−1 cm−1 with recovery of 98.5%–100.9% and R.S.D. of 1.82%. In addition, the determination limit of measurement was 0.017 mg m−3 nitrogen oxides and the determination range was 0.027–2.0 mg m−3 nitrogen oxides. This method can be easily applied to the determination of the nitrogen oxides in the air.
显示更多 [+] 显示较少 [-]Circadian rhythm of a red-tide dinoflagellate Peridinium quadridentatum in the port of Veracruz, Gulf of Mexico, its thecal morphology, nomenclature and geographical distribution 全文
2016
Okolodkov, Yuri B. | Campos-Bautista, Guadalupe | Gárate Lizárraga, Ismael
A circadian rhythm of the dinoflagellate Peridinium quadridentatum was studied at a time-series station in the southwestern Gulf of Mexico, in May 2007. Different substrates (water column, the seagrass Thalassia testudinum, macroalgae, coral rubble and sandy sediment surface) were sampled at the site at 1.5–3.5m depth. In the samples of coral rubble, P. quadridentatum was scarce. In the water column, the species showed an abundance peak at 15:00. The cell abundance of P. quadridentatum in Thalassia samples increased from 15:00 until 18:00 (1.81×104cells/gsubstratewet weight), and then continuously decreased until 06:00. Changes in P. quadridentatum cell abundance on macroalgae followed the same trend as on Thalassia, with the maximal value at 18:00. The higher abundance of P. quadridentatum (up to 1.40×104cells/gSWW) in macroalgae samples showed the preference for seaweeds. P. quadridentatum has a neritic tropical–boreal distribution. A new combination is proposed: Peridinium quadridentatum var. trispiniferum.
显示更多 [+] 显示较少 [-]Pollution from EOLV dismantling and the corresponding countermeasures 全文
2016
Zhang, Hu
There are problems associated with dismantling vessels that have reached the end of their life, when pollution problems associated with the process need to be addressed. The first problem in “end-of-life vessels” (EOLV) is to define their legal frameworks. The second problem is their dismantlement for recycling of ships. In order to reduce the effects of pollution caused by EOLV dismantling, the International Maritime Organization (IMO) adopted the Hong Kong Convention on 15 May 2009. While preparing for implementing the obligations under the Hong Kong Convention, China shall make effort on five aspects: (i) establish an ISRT for the safe and environmentally sound recycling of ships, (ii) improve the competitiveness of ship dismantling plants, (iii) strengthen international exchanges, (iv) amend the domestic laws and regulations, and (v) support from the China Classification Society.
显示更多 [+] 显示较少 [-]Characteristics of aerosols over Beijing and Kanpur derived from the AERONET dataset 全文
2016
Chen, Hao | Cheng, Tianhai | Gu, Xingfa | Li, Zhengqiang | Wu, Yu
Beijing and Kanpur are two cities identified as high aerosol optical thickness (AOT) and complex composition of aerosols in Asian monsoon regions. Detail knowledge of key aerosol types in these two countries would be helpful for clarifying the mechanisms of aerosol radiative forcing and improving the accuracy of satellite remote sensing in these two countries. This study examines the characteristics of aerosol types over Beijing and Kanpur derived from a 12-year dataset from Aerosol Robotic Network (AERONET) stations and compares them via cluster analysis of optical and microphysical properties. Aerosols in Beijing are more complex than in Kanpur. Four fine-size dominated aerosol types (including two types of moderately absorbing aerosols, one highly absorbing aerosol type and one non-absorbing aerosol type) and one coarse-size dominated aerosol type are identified over Beijing. In Kanpur, two fine-sized dominated aerosol types (one high absorbing aerosol type and one non-absorbing aerosol type) and one coarse-sized dominated aerosol type are obtained. Compared to Beijing, the average SSAs of non-absorbing and high-absorbing aerosols are lower for the four wavelengths (440 nm, 676 nm, 869 nm, 1020 nm) in Kanpur. High absorbing aerosols usually occur in the months December to February (DJF) for both sites. The proportion in Kanpur (14%) is about twice that in Beijing (7%). Non-absorbing aerosols are usually observed in the months June to August (JJA) for both sites. Their proportion in Kanpur (31%) is ∼3 times larger than that in Beijing (11%). Coarse aerosols are frequently observed in the months March to May (MAM) for both sites. Their proportion in Kanpur (54%) is two times larger than in Beijing (21%).
显示更多 [+] 显示较少 [-]Magnetic properties of air suspended particles in thirty eight cities from south India 全文
2016
Gargiulo, José D. | Kumar, R Senthil | Chaparro, Marcos A.E. | Chaparro, Mauro A.E. | Natal, Marcela | Rajkumar, P.
Air pollution is a basic problem nowadays and it requires special concern. In India, the air pollution is a growing problem because of the enhanced anthropogenic activities such as burning fossil fuels involving industrial processes and motor vehicles. We study airborne dust particles collected at the height of 7 m in roadside and land area from thirty-eight cities in the state of Tamil Nadu. The collection involves a total of 111 samples concerning vehicular, industrial and residential areas, and allows us to assess the spatial distribution of magnetic particles produced and emitted on a short period of time (about one month). Magnetic properties of these air suspended particles were determined by techniques of environmental magnetism, revealing the presence of magnetite and hematite. We found the overall average of mass-specific magnetic susceptibility χ of 589.0 × 10−8 m3 kg−1 and saturation of remanent magnetization SIRM of 68.1 × 10−3 A m2 kg−1; as well as χ and SIRM values higher than 900.0 × 10−8 m3 kg−1 and 700.0 × 10−3 A m2 kg−1, respectively, corresponding to the most impacted zones in industrial/vehicular areas and in cities located in the central/eastern region respectively (e.g.: Hosur, Krishnagiri, Salem, Dharapuram, Ranipet, Ayanavaram, Cuddalore and Chidambaram). We analyzed the relationship between magnetic parameters, between areas and possible grouping of cities using multivariate statistical analysis. The SEM-EDS observations and grain size estimations reveal the presence of trace elements (Sb, Zn, Co, Ni, As and V) and fine particles (1–5 μm) that can be inhaled and therefore are dangerous to human health.
显示更多 [+] 显示较少 [-]Long-term weathering and continued oxidation of oil residues from the Deepwater Horizon spill 全文
2016
White, Helen K. | Wang, Chloe H. | Williams, Patrick L. | Findley, David M. | Thurston, Alana M. | Simister, Rachel L. | Aeppli, Christoph | Nelson, Robert K. | Reddy, Christopher M.
To investigate the long-term weathering of oil from the Deepwater Horizon (DWH) incident, oil-soaked sand patties were collected from Gulf of Mexico beaches from Florida to Alabama over a three-year period from 2012 to 2014. Analysis of oil residues by gas chromatography with flame ionization detection (GC-FID), thin-layer chromatography with flame ionization detection (TLC-FID), and Fourier transform infrared spectroscopy (FT-IR) indicated uniformity in their chemical composition. Some variability within and between samples was observed, arising from differences in exposure to light and water, which increase the amount of weathering. Oxygenated hydrocarbons (OxHC) produced by weathering processes dominate the majority of oil residues. These OxHC have continued recalcitrance in the environment, and increase in relative abundance over time. Analyses of the bulk characteristics of oil residues via TLC-FID and FT-IR should be continued as these techniques provide important insight into the weathering state of oil residues.
显示更多 [+] 显示较少 [-]Superstorm Sandy marine debris wash-ups on Long Island — What happened to them? 全文
2016
Swanson, R Lawrence | Lwiza, Kamazima | Willig, Kaitlin | Morris, Kaitlin
Superstorm Sandy generated huge quantities of debris in the Long Island, NY coastal zone. However, little appears to have been washed offshore to eventually be returned to Long Island's beaches as marine debris wash-ups. Information for our analysis includes debris collection statistics, very high resolution satellite images, along with wind and sea level data. Rigorous debris collection efforts along with meteorological conditions following the storm appear to have reduced the likelihood of debris wash-ups.
显示更多 [+] 显示较少 [-]Detection of phthalate esters in seawater by stir bar sorptive extraction and gas chromatography–mass spectrometry 全文
2016
Si, Qingqing | Li, Fengmin | Gao, Chenchen | Wang, Cong | Wang, Zhenyu | Zhao, Jian
We developed the stir bar sorptive extraction (SBSE)–gas chromatography–mass spectrometry (GC–MS) method to detect 15 kinds of PAEs in seawater. The stir bars (20mm in length and 1mm in film thickness) coated with 150μL of polydimethylsiloxane (PDMS) were found to demonstrate the optimal extraction of PAEs. The optimal conditions were as follows: extraction time of 2h, extraction temperature of 25°C, sodium chloride of 5%, methanol of 10%, analytical time of 50min, and methanol–acetonitrile (4:1) as the solvent. SBSE–GC–MS revealed that under the set temperature, the chromatographic peaks of all 15 PAEs can appear with complete separation. The detection limit ranged from 0.07μg/L to 5.71μg/L, whereas the limit of quantification ranged from 0.023μg/L to 193μg/L, and the correlation coefficients between the chromatographic peak area and concentration of the PAEs were greater than 0.92.
显示更多 [+] 显示较少 [-]Bacteriological quality evaluation of seawater and oysters from the Jaranman-Saryangdo area, a designated shellfish growing area in Korea: Impact of inland pollution sources 全文
2016
Mok, Jong Soo | Lee, Ka Jeong | Kim, Poong Ho | Lee, Tae Seek | Lee, Hee Jung | Jung, Yeoun Joong | Kim, Ji Hoe
From 2011 to 2013, we conducted a full sanitary survey of pollution sources in proximity to a designated shellfish growing area in Korea, and their impact on the sea area therein. From this area, 836 seawater samples and 93 oyster samples were examined to evaluate their bacteriological quality. There were 483 potential pollution sources in the drainage area of the Jaranman-Saryangdo area, including 38 sources discharging water. It demonstrates that while many pollution sources have been identified, no significant impact occurred within the designated shellfish growing area. Variations in fecal coliform (FC) levels in seawater were closely related to rainfall. The FC levels of seawater and oysters from the designated area met the regulation limits set by various countries. Our study indicates that the oysters produced in this area are apparently safe for raw consumption based on their bacterial quality.
显示更多 [+] 显示较少 [-]Characteristics of water-soluble inorganic species in PM10 and PM2.5 at two coastal sites during spring in Korea 全文
2016
Park, Seung-Shik | Cho, Sŏng-yong | Jung, Chang-hoon | Lee, Kwon-Ho
PM10 and PM2.5 were collected during spring at East (“Gangneung”) and West (“Taean”) coastal sites of the Korean peninsula to investigate chemical characteristics and likely formation routes of their water-soluble inorganic species. The Gangneung site is inland, about 4.5–5.0 km from the East Sea; the Taean site is about 200 m from the coastline and about 400 km from eastern China. The total water-soluble ionic species contributions to PM10 and PM2.5 were respectively 28.8 and 37.4% at the Gangneung site and 46.8 and 53.1% at the Taean site. Concentrations of SO42−, NH4+, and NO3− in both PM10 and PM2.5 were found to be two times higher at the Taean site than at the Gangneung site. The potential source contribution function (PSCF) maps indicate that the enhancement of PM10 and its secondary aerosol species concentrations at two sites were primarily the result of atmospheric processing during long-range transport from the polluted regions of eastern China. Also upwind sources (“the capital region of Korea”) and local emissions influenced the concentration levels of secondary inorganic species at Gangneung.SO42− events, defined by PM10SO42− concentrations exceeding the average by one standard deviation, were identified at the two sites – six at Gangneung and four at Taean – to investigate possible mechanisms for the formation of SO42− and NO3−. High SO42− and high NO3− at the Gangneung site were strongly associated with either high RH (89–94%) and low wind speed or high O3 (62–103 ppb), suggesting that either gas-phase oxidation or aqueous phase oxidation played a critical role in the enhanced SO42− production. On the other hand, at the Taean site the association was with both high RH (76–92%) and high O3 (53–79 ppb), indicating that these conditions trigger aqueous-phase and gas-phase reactions to produce secondary SO42− and NO3− particles. Also long-range transport of air masses could be one possible factor for enhanced SO42− and NO3− concentrations during the events at the two coastal sites, as evidenced by PSCF maps.
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