خيارات البحث
النتائج 1441 - 1450 من 4,086
Determination of PM2.5 and polycyclic aromatic hydrocarbons from incense burning emission at shrine for health risk assessment النص الكامل
2016
Bootdee, Susira | Chantara, Somporn | Prapamontol, Tippawan
This study aims to determine fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) bounded with PM2.5 emitted from incense burning at shrine to assess human health risk. The PM2.5 samples were collected by a mini volume air sampler during special occasions and normal period at a shrine located in the city center of Chiang Mai, Thailand. The samples were analyzed for 16-PAHs by GC–MS. The descending order of 8- and 24-hrs PM2.5 concentrations (μg/m3) were 625 ± 147 and 406 ± 159 (Chinese New Year) > 184 ± 85 and 133 ± 71 (other special occasions) > 100 ± 35 and 50 ± 20 (normal period). Their concentrations in each occasion were significantly different due to number of visitors and amount of incense being burned. Total PAHs concentrations (ng/m3) for 8- and 24-hrs in descending order were 90 ± 41 and 45 ± 29 (Chinese New Year), 71 ± 30 and 30 ± 12 (other special occasions) and 25 ± 15 and 14 ± 9 (normal periods). Correlation between PM2.5 and total PAHs concentrations was relatively strong. In addition, PM2.5 concentrations were highly correlated (r = 0.618) with carcinogenic PAHs (c-PAHs) indicated that carcinogenic compounds were dominant in particulate PAHs and generated from incense burning. The values of toxicity equivalent concentration (TEQ) indicate human health risk from PAHs inhalation. According to European guideline, it should be less than1 ng/m3 in ambient air. During Chinese New Year, they were relatively high (32 ± 27 ng/m3 (8 h) and 10 ± 4 ng/m3 (24 h)). Moreover, the isometric ratio analysis revealed that emission from incense burning was the main source of PM2.5 and PM2.5-bound PAHs.
اظهر المزيد [+] اقل [-]Characteristics of nutrients and phytoplankton productivity in Guangdong coastal regions, South China النص الكامل
2016
Zhang, Ling | Shi, Zhen | Zhang, Jingping | Jiang, Zhijian | Huang, Liangmin | Huang, Xiaoping
In order to evaluate the levels and the influence on phytoplankton productivity of dissolved nutrients, concentrations and distribution of N, P and Si were studied in coastal areas profoundly influenced by human activities in Guangdong Province, South China. Generally, concentrations of dissolved inorganic nitrogen were high in wet periods because of the inputs from strong seasonal land runoff. Si and P concentrations were generally low in summer due to the consumption by phytoplankton growth. Dissolved organic N and P were important in study area. Chl a and primary productivity (PP) were relatively high and showed seasonal and geographical variations. Concentrations of Chl a were the highest in summer, and the high water temperature and sufficient illumination accelerated the growth of phytoplankton, especially in surface water. Additionally, water stratification in summer decreased mixed layer depth and trapped PP in upper layer.
اظهر المزيد [+] اقل [-]The nutrient load from food waste generated onboard ships in the Baltic Sea النص الكامل
2016
Wilewska-Bien, Magda | Granhag, Lena | Andersson, Karin
The combination of the sensitive characteristics of the Baltic Sea and the intense maritime traffic makes the marine environment vulnerable to anthropogenic influences. The theoretical scenario calculated in this study shows that the annually generated food waste onboard ships in traffic in the Baltic Sea contains about 182tonnes of nitrogen and 34tonnes of phosphorus. Today, all food waste generated onboard can be legally discharged into the marine environment at a distance of 12NM from the nearest land. The annual load of nitrogen contained in the food waste corresponds to 52% of load of nitrogen from the ship-generated sewage. Future regulations for sewage discharge in the Baltic Sea will require significant reduction of total nitrogen and phosphorus released. The contribution of nutrients from food waste compared to sewage will therefore be relatively larger in the future, if food waste still can be legally discharged.
اظهر المزيد [+] اقل [-]Antibiotic and heavy metal resistance in Shewanella putrefaciens strains isolated from shellfishes collected from West Sea, Korea النص الكامل
2016
Kang, Chang-Ho | So, Jae-Seong
The aim of the present study was to determine the antibiotic resistance patterns and distribution of heavy-metal resistance in Shewanella putrefaciens strains isolated from shellfishes collected from West Sea; and to determine the relationship, if any, between antibiotic and heavy-metal resistance in these strains. Among the 15 strains isolated, two strains, SY1 and SY2, showed heavy-metal resistance in addition to high resistance to seven antibiotics: cephalothin, gentamicin, erythromycin, vancomycin, ampicillin, rifampicin, and streptomycin. We conclude that heavy-metal contamination imposes long-term, widespread, and recalcitrant selection pressure, which potentially contributes to the maintenance and spread of antibiotic resistance factors in bacteria. Moreover, this fact holds both environmental and clinical importance.
اظهر المزيد [+] اقل [-]Estimating the carrying capacity of green mussel cultivation by using net nutrient removal model النص الكامل
2016
Srisunont, Chayarat | Babel, Sandhya
This study aims to evaluate the nutrient removal potential and carrying capacity of green mussel cultivation by using the mass balance model. The developed model takes into consideration the green mussel growth rate, density and chlorophyll a concentration. The data employed in this study were based on culture conditions at Sriracha Fisheries Research Station, Thailand. Results show that net nutrient removal by green mussel is 3302, 380, and 124mg/year/indv for carbon, nitrogen, and phosphorus respectively. The carrying capacity of green mussel cultivation was found to be 300indv/m2 based on chlorophyll a concentration which will not release phosphorus in the water environment beyond the standard (45μg-PO4−3-P/L). Higher chlorophyll a concentration results in lowered green mussel carrying capacity. This model can assist farm operators with possible management strategies for a sustainable mussel cultivation and protection of the marine environment.
اظهر المزيد [+] اقل [-]Aragonite saturation state and dynamic mechanism in the southern Yellow Sea, China النص الكامل
2016
Xu, Xuemei | Zang, Kunpeng | Huo, Cheng | Zheng, Nan | Zhao, Huade | Wang, Juying | Sun, Bing
Based upon surveys conducted in November 2012 and June 2013, the distribution and dynamics of aragonite saturation state (Ωarag) were investigated in the southern Yellow Sea (SYS) of China. In summer, surface water Ωarag ranged from 2.1–3.8 and enhanced biological production fueled by Changjiang River freshwater input increased Ωarag to 3.8 in the southern SYS. However, subsurface water Ωarag was <2.0 in the central SYS. During autumn, surface water Ωarag was 2.0–2.9, lower than that in summer due to ventilation between surface and low Ωarag (1.0–1.4) subsurface waters in the central SYS. Community respiration and/or aerobic remineralization dominated low Ωarag in subsurface waters, while water stratification influenced the level and scale of acidity accumulation. By the end of this century, waters with Ωarag>2.0 could disappear from the SYS with increasing atmospheric CO2, while bottom waters Ωarag may become undersaturated due to the impact of eutrophication.
اظهر المزيد [+] اقل [-]Seasonal variation in diffusive exchange of polycyclic aromatic hydrocarbons across the air–seawater interface in coastal urban area النص الكامل
2016
Kim, Seung-Kyu | Chae, Doo Hyun
Concentrations of 15 polycyclic aromatic hydrocarbons (PAHs) in air–seawater interface were measured over 1year in the coastal region of Incheon, South Korea. Most individual PAHs and total PAHs in air displayed statistically significant negative correlations with temperature, but not significant in seawater. Less hydrophobic compounds with three rings were at or near equilibrium in summer, while PAHs with four to six rings were in disequilibrium in all seasons, with higher fugacity gradients in colder seasons and for more hydrophobic compounds. Differently from fugacity gradients, the highest net fluxes occurred for some three- and four-ring PAHs showing the highest atmospheric concentrations. Net gaseous exchange, which was higher in winter, occurred from air to seawater with an annual cumulative flux of 2075μg/m2/year (for Σ15PAHs), indicating that atmospheric PAHs in this region, originating from coal/biomass combustion, can deteriorate the quality of seawater and sediment.
اظهر المزيد [+] اقل [-]Environmental implications of the use of sulfidic back-bay sediments for dune reconstruction — Lessons learned post Hurricane Sandy النص الكامل
2016
Plumlee, Geoffrey S. | Benzel, William M. | Hoefen, Todd M. | Hageman, Philip L. | Morman, Suzette A. | Reilly, Timothy J. | Adams, Monique | Berry, Cyrus J. | Fischer, Jeffrey M. | Fisher, Irene
Some barrier-island dunes damaged or destroyed by Hurricane Sandy's storm surges in October 2012 have been reconstructed using sediments dredged from back bays. These sand-, clay-, and iron sulfide-rich sediments were used to make berm-like cores for the reconstructed dunes, which were then covered by beach sand. In November 2013, we sampled and analyzed partially weathered materials collected from the cores of reconstructed dunes. There are generally low levels of metal toxicants in the reconstructed dune materials. However oxidation of reactive iron sulfides by percolating rainwater produces acid-sulfate pore waters, which evaporate during dry periods to produce efflorescent gypsum and sodium jarosite salts. The results suggest use of sulfidic sediments in dune reconstruction has both drawbacks (e.g., potential to generate acid runoff from dune cores following rainfall, enhanced corrosion of steel bulwarks) and possible benefits (e.g., efflorescent salts may enhance structural integrity).
اظهر المزيد [+] اقل [-]Temporal and spatial distribution of semicarbazide in western Laizhou Bay النص الكامل
2016
Tian, Xiuhui | Xu, Yingjiang | Song, Xiukai | Gong, Xianghong | Liu, Yihao | Zhou, Quanli | Wang, Zhongquan | Xia, Chuanhai
Semicarbazide (SEM), an industrial raw material and the marker residue of nitrofurazone as a veterinary drug, has become a new type of marine pollutant. A standard method (ultra-performance liquid chromatography–tandem mass spectrometry, UPLC–MS/MS) was used to analyze SEM in seawater, sediment, and shellfish. A series of sections and stations were set up in radical distribution in western Laizhou Bay, with six voyages and 150 monitoring samples. The concentrations of SEM in seawater and shellfish were 10−11 and 10−10kg/L, respectively, and no SEM was detected in the sediment. Distribution characteristics at each state, temporal and spatial trends, multivariate analyses, and the causes were analyzed to assess the pollution level, which aimed to offer a database for drafting the national baseline values of SEM in seawater and sediment in future. The data obtained could be used for integrated watershed management of marine environment and economic activities for constructing a blue economic zone of Shandong Peninsula in China.
اظهر المزيد [+] اقل [-]Determination of ciprofloxacin in Jiaozhou Bay using molecularly imprinted solid-phase extraction followed by high-performance liquid chromatography with fluorescence detection النص الكامل
2016
Lian, Ziru | Wang, Jiangtao
A high selective pre-treatment method for the cleanup and preconcentration of ciprofloxacin in natural seawater samples was developed based on molecularly imprinted solid-phase extraction (MISPE). The ciprofloxacin imprinted polymers were synthesized and the characteristics of obtained polymers were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy and binding experiments. The imprinted materials showed high adsorption ability for ciprofloxacin and were applied as special solid-phase extraction sorbents for selective separation of ciprofloxacin. An off-line MISPE procedure was optimized and the developed MISPE method allowed direct purification and enrichment of the ciprofloxacin from the aqueous samples prior to high-performance liquid chromatography analysis. The recoveries of spiked seawater on the MISPE cartridges ranged from 75.2 to 112.4% and the relative standard deviations were less than 4.46%. Five seawater samples from Jiaozhou Bay were analyzed and ciprofloxacin was detected in two samples with the concentrations of 0.24 and 0.38μgL−1, respectively.
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