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761.
Sheng-Chieh Chen Chuen-Jinn Tsai Charles C.-K. Chou Gwo-Dong Roam Sen-Sung Cheng Ya-Nan Wang 《Atmospheric environment (Oxford, England : 1994)》2010,44(4):533-540
Atmospheric ultrafine particles (UPs or PM0.1) were investigated at the roadside of Syuefu road in Hsinchu city, in the Syueshan highway tunnel in Taipei and in the NTU Experimental Forest in Nantou, Taiwan. A SMPS (TSI 3936) and three MOUDIs (MSP 110) were collocated to determine the number and mass concentrations of the PM0.1 simultaneously. The filter samples were further analyzed for organic carbon (OC), element carbon (EC), water-soluble ions and trace elements. Taking into account the OC artifact of PM0.1, good chemical mass closure (ratio of the reconstructed chemical mass to the gravimetrical mass of PMs) was obtained with an unknown percentage of 10.6, 26.2 and 37.2% at the roadside, tunnel and forest, respectively. The unexplained mass was attributed to aerosol water in this study. The artifact at the roadside, tunnel and the forest PM0.1 mass was found to be as high as 51.6 ± 10.7%, 20.0 ± 5.4% and 85.6 ± 18.4%, respectively. Finally, the effective density of the roadside, tunnel and forest PM0.1 was calculated based on the results of chemical speciation and found to be 1.45, 1.29 and 1.22 g cm?3, respectively, which was in good agreement with that obtained by using the method of Spencer et al. (2007). Based on these results, it is foreseeable that the number concentration of the SMPS can be converted using the effective density determined by Spencer et al. (2007) for the real time measurement of the PM0.1 concentration. 相似文献
762.
固相萃取与气相色谱-质谱联用测定水中痕量多环芳烃 总被引:3,自引:0,他引:3
采用固相萃取与气相色谱-质谱联用测定水中痕量多环芳烃(PAHs)。通过正交试验,得到最佳固相萃取条件为:上样流速为5mL/min、采用二氯甲烷洗脱、洗脱剂用量为3mL、洗脱流速为2mL/min。测定结果显示,固相萃取与气相色谱—质谱联用技术对萘、菲、荧蒽3种PAHs的检出限为0.03~0.07μg/L,加标回收率为70%~100%,相对标准偏差为3.90%~9.58%。该方法精密度高、准确度好,能满足实际水样中痕量PAHs的测定要求。 相似文献
763.
764.
Miao-Ching Cheng Chen-Feng You Fei-Jan Lin Chuan-Hsiung Chung Kuo-Fang Huang 《Atmospheric environment (Oxford, England : 1994)》2010,44(28):3386-3393
We investigated chemical and Sr isotopic composition of monthly rainwater collected on Peng-Chia-Yu (PCY) in northern Taiwan. Rainwater 87Sr/86Sr ratios, Na/Cl, Ca/Cl, Sr/Cl, Sr/Ca, NH4/Cl, NO3/Cl, SO4/Cl and Na/Sr, showed clear seasonal cycles, reflecting mixture of loess carbonates (high Ca/Sr and more radiogenic 87Sr/86Sr) and seawater (low Ca/Sr and intermediate 87Sr/86Sr). Model results showed that the former source contributes up to 45% during the winter monsoon period, but seawater is the dominant Sr source in rainwater (>50%) at other times. Two anomalously low 87Sr/86Sr values occurred in July and August 1998, coinciding with the Merapi eruption in Indonesia. Air-mass backward trajectories and the geochemical and isotopic compositions in rainwater and Merapi lava (i.e. Ca/Sr = 100 and 87Sr/86Sr = 0.705400) suggested that the Merapi eruption delivered ash across the western equatorial Pacific to PCY. Aerosols leaching experiments were conducted to examine the impact of the 1998 eruption, demonstrating that only a minor terrestrial signature can be extracted by distilled water, implying rapid dispatch of volcanic gases or high-efficiency dissolution of ash related substance in acidic rains. 相似文献
765.
Cheng WL 《Environmental monitoring and assessment》2001,66(1):77-98
Sulphur dioxide (SO2) is one of the main atmospheric pollutants in central Taiwan. This article analyses the SO2 concentration seasonal variations and spatial distribution using data obtained from ten air quality monitoring stations and the Taiwan Weather Bureau. It reveals that SO2 concentration is high in winter and low in summer and that high concentration centers are located south of the Taichung coal-fired power plant, the main source of SO2 emissions in the region.The location of high concentration centers changeswith different prevailing winds. SO2 variations due towind direction are not unique. During short periods,when meteorological conditions are constant, variationin the pollution sources cause variations in thespatial distribution. This has been deduced byappreciation of Intervention analysis to time seriesof hourly data. 相似文献
766.
Fan W Cui M Liu H Wang C Shi Z Tan C Yang X 《Environmental pollution (Barking, Essex : 1987)》2011,159(3):729-734
The acute toxicity of engineered nanoparticles (NPs) in aquatic environments at high concentrations has been well-established. This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO2 remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2 mg L−1 nano-TiO2, the (LC50) of Cu2+ concentration observed to kill half the population, decreased from 111 μg L−1 to 42 μg L−1. Correspondingly, the level of metallothionein decreased from 135 μg g−1 wet weight to 99 μg g−1 wet weight at a Cu2+ level of 100 μg L−1. The copper was found to be adsorbed onto the nano-TiO2, and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO2 may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins. 相似文献
767.
With their widespread application in agriculture, industry, culture, medicine, and daily life, lanthanide compounds are being brought into the ecological environment and human body through food chains. It is important to know the acute and chronic effects of lanthanides on the environment, nature balance, and the human body after their entry into bodies and the environment. Lanthanides have been demonstrated to cause spleen apoptosis and decreased immunity of mice, but very little is known about the molecular aspects of these mechanism. In order to understand the spleen apoptotic mechanism induced by intragastric administration of 2, 10 and 20 mg kg(-1) body weight CeCl(3) for consecutive 60 d, we investigated the cerium accumulation, apoptosis, the expression levels of the apoptosis-related cytokines into apoptosis-related genes and proteins. The results demonstrated that cerium had obvious accumulation in the mouse spleen, leading to the significant increase of the spleen indices and splenocyte apoptosis. Furthermore, CeCl(3) could effectively activate caspase-3 and -9, decrease the Bcl-2 the levels of gene and protein, and increase the levels of Bax, and cytochrome c genes and their protein expressions, and promote reactive oxygen species production. It implied CeCl(3)-induced apoptosis in the mouse spleen via intrinsic pathway. Our findings suggest the need for great caution to handle the lanthanides for workers and consumers. 相似文献
768.
Shao D Liang P Kang Y Wang H Cheng Z Wu S Shi J Lo SC Wang W Wong MH 《Chemosphere》2011,83(4):443-448
This study investigated total mercury (THg) and methylmercury (MeHg) concentrations in five species of freshwater fish and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The concentrations of THg and MeHg in fish pond surface sediments were 33.1-386 ng g(-1) dry wt and 0.18-1.25 ng g(-1) dry wt, respectively. The age of ponds affected the surface sediment MeHg concentration. The vertical distribution of MeHg in sediment cores showed that MeHg concentrations decreased with increasing depth in the top 10 cm. In addition, a significant correlation was observed between %MeHg and DNA from Desulfovibrionacaea or Desulfobulbus (p<0.05) in sediment cores. Concentrations of THg and MeHg in fish muscles ranged from 7.43-76.7 to 5.93-76.1 ng g(-1) wet wt, respectively, with significant linear relationships (r=0.97, p<0.01, n=122) observed between THg and MeHg levels in fish. A significant correlation between THg concentrations in fish (herbivorous: r=0.71, p<0.05, n=7; carnivorous: r=0.77, p<0.05, n=11) and corresponding sediments was also obtained. Risk assessment indicated that the consumption of largemouth bass and mandarin fish would result in higher estimated daily intakes (EDIs) of MeHg than reference dose (RfD) for both adults and children. 相似文献
769.
770.