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341.
诺氟沙星对海月水母螅状体Hsp70基因、GTP结合蛋白基因和氧化应激蛋白基因表达的影响 总被引:1,自引:0,他引:1
诺氟沙星(norfloxacin,NFLX)广泛应用于水产养殖中的鱼类细菌性疾病治疗。为探讨诺氟沙星对海洋生物的毒性作用,选择海月水母螅状体为受试生物,考察了不同浓度诺氟沙星和不同暴露时间对GTP结合蛋白(GTP binding protein)、氧化应激蛋白(oxidative stress protein)和热休克70 k Da蛋白(heat shock 70 k Da protein,Hsp70)表达量的影响。结果表明,NFLX对海月水母螅状体的48 h的半致死浓度(48 h-LC_(50))是415.1 mg·L~(-1),NFLX对海月水母螅状体的毒性属于低毒。随着NFLX浓度的升高和培养时间的延长,Hsp70基因在第7天浓度300 mg·L~(-1)时表达量受到显著性诱导(P0.05),较对照组升高9.1倍;GTP结合蛋白基因和氧化应激蛋白基因的表达量都呈现先急剧升高后降低的趋势。2个基因均在第1天受到显著性诱导(P0.05),分别在NFLX浓度100 mg·L~(-1)和300 mg·L~(-1)时表达量达到最大值,较对照组升高10.15倍和50.5倍。Hsp70基因、GTP结合蛋白基因和氧化应激蛋白基因在实验期间都对NFLX表现出较好的响应。 相似文献
342.
环境空气质量指数计算方法与分级方案比较 总被引:6,自引:4,他引:2
环境空气质量指数(AQI)广泛应用于各国环境空气质量评价体系之中,旨在为公众提供简单明了的空气质量信息和健康指引。通过对不同国家和地区空气质量指数的名称、计算方法、分级方案进行深入分析和比较,系统分析了各种空气质量指数的优缺点,并针对我国当前的空气质量指数体系存在的问题提出了相应的改进建议。 相似文献
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Phenolic compounds are partly known as endocrine disruptors with various harmful effects including feminization and carcinogenesis at very low concentrations. Consequently, the pathways and removal of these compounds in natural and artificial sewage treatment systems such as wetlands have received wide concern. In this paper, a natural reed bed wetland with an area of 695 ha located in the Liaohe River estuary in Northeast China was employed as a demonstration site to study the retention and removal efficiency of phenolic compounds including 4-nonylphenol (4-NP), bisphenol A (BPA), 4-t-octylphenol (4-t-OP), and 2,4-dichlorophenol (DCP), and to evaluate their purification capacity via water and mass balance analyses during an irrigation period from May 9 to September 8, 2009. The results showed that the phenolic compounds could be retained in the wetland system and removed through various processes. On average, 27.5% of phenolic compounds could be retained by the wetland substrate during the initial three-day irrigation period with a retention capacity order of 4-t-OP > 4-NP > BPA > DCP. During the following 120 d irrigation period, the phenolic compounds could be efficiently removed with an average percentage of 91.6%. It is estimated that 1.76 kg d−1 of phenolic compounds could be removed by the Liaohe River estuarine wetland (∼8 × 104 ha). The reed bed wetland system therefore provides a feasible mitigation option for phenolic pollutants in sewage and wastewater. 相似文献
346.
A novel method dependent only on the mixture information (MIM) for evaluating the toxicity of mixture 总被引:2,自引:0,他引:2
Zhang J Liu SS Liu HL Zhu XW Mi XJ 《Environmental pollution (Barking, Essex : 1987)》2011,159(7):1941-1947
Compound contamination and toxicity interaction necessitate the development of models that have an insight into the combined toxicity of chemicals. In this paper, a novel and simple model dependent only on the mixture information (MIM), was developed. Firstly, the concentration-response data of seven groups of binary and multi-component (pseudo-binary) mixtures with different mixture ratios to Vibrio qinghaiensis sp.-Q67 were determined using the microplate toxicity analysis. Then, a desirable non-linear function was selected to fit the data. It was found that there are good linear correlations between the location parameter (α) and mixture ratio (p) of a component and between the steepness (β) and p. Based on the correlations, a mixture toxicity model independent of pure component toxicity profiles was built. The model can be used to accurately estimate the toxicities of the seven groups of mixtures, which greatly simplified the predictive procedure of the combined toxicity. 相似文献
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Marta Doval Miñarro Enrique González Ferradás Jonathan Barberá Rico Fernando Díaz Alonso Francisco J. Marzal Martínez Cristina Romero Trigueros 《Environmental science and pollution research international》2011,18(3):436-445
Introduction
The change in light intensity that takes place when an ambient air sample is drawn into the detection chamber of a chemiluminescence monitor generates changes in the concentrations of several species, such as NO2, NO and O3. Although this phenomenon has been known for several decades, there is still no commonly accepted approach on when or how to correct for it in NO2 and O3 readings. 相似文献349.
As a result of the changes that occur during their use, used engine oils tend to differ in chemical and physical composition from a virgin oil. In general recycled oils have: much higher water and sediment levels than virgin oil; relatively higher concentrations of organic compounds (oxidation products); and relatively higher levels of metals such as Fe, Cd, Cr, Pb, etc. Therefore, the aim of this work was to investigate, assess and to observe, by means of the physical and the chemical properties of the oils, atomic absorption (AA), inductive couple plasma (ICP) and Fourier transform infrared (FTIR) analyses the extent of the differences occurring between the virgin and recycled oil. In important part of this work was also the development of analytical techniques based on the use of FTIR spectroscopy; in relation to the rapid analysis of lubricants; in particular for the differentiation of virgin and recycled oil. The results obtained were expected to be useful for differentiation purposes, providing information on whether the metal concentrations and oxidation products could be an appropriate feature for differentiating a particular oil sample from the others. This work is categorized into a two-step procedure. Firstly, an evaluation of a typical FTIR spectrum of an engine oil sample (mono- and multigrade) is presented. The broad feature centered at 1716 cm(-1) is due to the presence of carbonyl containing degradation products of oil. A band observed at 1732, 1169, 1154 and 1270 cm(-1) assigned to the polymethacrylate stretching vibrations, allows the determination of viscosity modifier and pour point depressant additives. The observed differences in the specific spectral bands (1732, 1169, 1154 and 1270 and 1716 cm(-1)) are investigated and discussed. Secondly, an analytical technique for the measurement of the levels of the wear metals is also applied. 相似文献
350.
Youguo Gong Min Hu Yafang Cheng Hang Su Dingli Yue Feng Liu A. Wiedensohler Zhibin Wang H. Kalesse Shang Liu Zhijun Wu Kaitao Xiao Puchun Mi Yuanhang Zhang 《Atmospheric environment (Oxford, England : 1994)》2010,44(27):3278-3285
The coagulation sink and its role in new particle formation are investigated based on data obtained during the PRIDE-PRD2004 campaign at Xinken of Pearl River Delta, China. Analysis of size distributions and mode contributions of the coagulation sink show that the observed higher load of accumulation mode particles impose a significant effect on the coagulation sink and result in higher coagulation sinks at Xinken despite of the lower total particle number compared with other areas. Hence it is concluded that the higher coagulation sink may depress the occurrence frequency of new particle formation events. The strategies targeting at controlling accumulation mode particles may have influences on the frequency of new particle formation events at this area. The factors affecting the coagulation sink are evaluated. The relatively lower ambient relative humidities may weaken the coagulation sink and facilitate the occurrence of new particle formation events during noontime, while the surmise of nucleation and growth involving organic matter may imply an actually higher coagulation sink than expected. These factors have a significant influence on the ultimate fate of the newly formed nuclei and new particle formation. A comparison of event and non-event days indicates that the coagulation sink is not the only decisive factor affecting new particle formation, other factors including the precursor vapors and photochemical activity are none the less important either. Competition of coagulation sink and high source rate leads to the occurrence of new particle formation events at Xinken. 相似文献