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431.
Polybrominated diphenyl ethers (PBDEs) are new kinds of persistent organic pollutants (POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE (BDE-47) and deca-BDE (BDE-209) were applied, and their toxic effects on the swimming behavior, population growth and reproduction of Brachionus plicatilis were investigated. The results showed that: (1) The actual concentrations of BDE-47 and -209 in the seawater phase measured by GC–MS (Gas Chromatography−Mass Spectrometer) were much lower than their nominal concentrations. (2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 is more toxic than BDE-209. (3) Both BDE-47 and -209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females (OF/NOF), the ratio of mictic females/amictic females (MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and -209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.  相似文献   
432.
应用概率物种敏感度分布法研究太湖铜水生生物水质基准   总被引:3,自引:1,他引:2  
运用概率物种敏感度分布法获得太湖水体中铜的急性水质基准值为14.57μg·L-1,慢性水质基准值为3.26μg·L-1;不同类别物种敏感性存在差异,无脊椎动物较脊椎动物更敏感,甲壳类敏感性大于鱼类。概率物种敏感度分布法与传统的物种敏感度分布法相比,更全面合理地考虑多种毒性效应,曲线拟合效果好,受数据量大小影响较小,结果更加稳定。研究结论可为铜水质标准的修订和太湖流域水环境管理提供技术支持。  相似文献   
433.
非点源污染河流水环境容量的不确定性分析   总被引:8,自引:2,他引:6  
基于河流一维水环境容量计算模型和实测水文水质参数的统计分析,应用MonteCarlo模拟方法,分析模型各输入参数的灵敏度以及水环境容量值的概率分布,建立了非点源污染河流水环境容量的分期不确定性分析方法.本方法表达了由于获取的河流系统信息不确定性和非点源污染发生的随机性引起的水环境容量计算结果不确定性,给出了不同水文期在不同可信度下的河流水环境容量,为实现非点源污染的总量控制提供了可靠的基础.应用本方法,对长乐江的总氮水环境容量进行了不确定性分析.结果表明,根据水质控制目标,枯水期、平水期、丰水期中90%可信度的总氮水环境容量分别为487.9、949.8、1392.8kg·d-1,其中稀释容量是各水文期水环境容量的主要组成部分.据此,各水文期流域内的总氮现状入河量需削减1258.3~3591.2kg·d-1,丰水期是削减量最大的时期.不确定性分析方法计算得到的水环境容量是基于非点源污染河流水文水质状况的实际变化,这相对于按某一设计流量来确定水环境容量的常规方法更为科学、合理,拓展了水环境容量的研究思路和方法.  相似文献   
434.
In order to reduce secondary pollution during the incineration of composite refuse derived fuel (CRDF), the combustion features and the emission behavior of chlorine in CRDF containing coal were analyzed. The former was analyzed using thermo-gravimetric and the latter by gas chromatography–mass spectrometry. The release rate of inorganic chlorine during combustion reached 90 mass% at temperature between 773.15 and 873.15 K. On the other hand, approximately 84 mass% release rates was resulting from pyrolysis at 723.15 K. When temperature reached above 1073.15 K, it was noticed that higher concentration of organic chlorine in different organic compounds were produced in the processing of pyrolysis compared with those released from the combustion processing. From the thermo-gravimetric analysis using a self-designed system, three distinct phases were detected in the thermal process of CRDF. The first phase occurred at temperature between 473 and 573 K and its mass loss was about 38.50%. The second phase between temperature regions of 673–773 K with a mass loss of 20.35%. The third phase was observed at the temperature between 873 and 1073 K with 22.25% mass loss.  相似文献   
435.
A Fenton process that uses FeCl2 as the alternative catalyst was employed to deal with the biologically treated landfill leachate. Data obtained revealed that this Fenton process can provide an equivalent pollutant removal as the Fenton process that uses FeSO4 as catalyst. Central composite design (CCD) and response surface methodology (RSM) were applied to evaluate and optimize the four key factors, namely initial pH, Fe(II) dosage ([Fe2+]), H2O2/Fe(II) mole ratio ([H2O2]/[Fe2+] ratio) and reaction time, which affect the performance of the Fenton treatment. Chemical oxygen demand (COD) and color were selected as response variables. This approach provided statistically significant quadratic models, which were adequate to predict responses and to carry out optimization under the conditions studied. It was demonstrated that the interaction between initial pH and [H2O2]/[Fe2+] ratio has a significant effect on the COD removal, while the interaction between [H2O2]/[Fe2+] ratio and reaction time shows a large impact on color removal. The optimal conditions were found to be initial pH 5.9, [Fe2+] = 9.60 mmol/L, [H2O2]/[Fe2+] ratio = 2.38, reaction time = 5.52 h. Under this optimal scheme, the COD and color in the effluent were reduced to 159 mg/L and 25°, respectively, with an increase of BOD5/COD ratio from 0.05 to 0.21.  相似文献   
436.
高性能纤维具有优异的理化性能,在个体防护领域有着广泛的应用。本文介绍了高性能纤维在软质防弹服领域的应用与发展,分析了其优点与缺点,并讨论了软质防弹服发展方向。  相似文献   
437.
The aim of this paper is to study the spatialtemporal differentiation of industrial eco-efficiency in China. Using methods based on the data envelopment analysis (DEA) model and exploratory spatial data analysis (ESDA) and data from 1985, 1995, 2005, and 2008 of 30 provinces in China, the spatial-temporal pattern changes in industrial eco-efficiency are discussed. The results show that: first, the patterns of industrial eco-efficiency are dominated by clustering of relatively low efficiency provinces; second, spatial relationships between the industrial eco-efficiencies of different provinces changed slightly throughout the period and the provinces persistently exhibit spatial concentration of relatively low industrial eco-efficiency; finally, there is an obvious trend in the polarization of industrial eco-efficiency, i.e., the higher level spatial units are concentrated in eastern China, and the lower level spatial units are mainly in western and central China.  相似文献   
438.
Tetrahydrofuran (THF) is easy to volatilize and hard to biodegrade. Little is known about the influence and fate of tetrahydrofuran in the environment. The effects of THF were examined on dissolved oxygen, pH, culturable aerobic microbes (bacteria, actinomycetes, and fungi) and four selected enzymes (protease, phosphatase, amylase, and lipase) in wastewater. The wastewater containing some activated sludge was taken from the aeration basin in Sibao sewage plant in Hangzhou, China. THF at lower concentrations of enhanced aerobic respiration and higher concentrations decreased utilization of oxygen in wastewater. The short-term influence of THF on pH was not obvious, but the long-term effect was apparent. Inhibition of THF on culturable aerobic microbes rose with increasing THF concentrations but decreased with prolongation of incubation time. No effect of THF on the activity of protease, phosphatase, amylase, and lipase was found. Data indicate that lower concentrations of THF exert no marked influence on wastewater in an urban sewage plant.  相似文献   
439.
大亚湾的海     
吕军 《环境》2006,(4):54-54
看海,是我童年的一个梦想。三年前的一天,这个梦想成了现实。  相似文献   
440.
Cytochrome P450 (CYP450) genes play an important role in catalyzing oxidative metabolism of toxicants. Recently, CYP1 subfamily were discovered and reported in fish, however, little is known regarding the CYP2 isoforms in fish. In the present study, the cDNA fragments of CYP 1B1 and 1C1 and CYP2Aa, 2Y3, and 2K of rare minnow were cloned and exhibited a high amino acid sequence identity compared with their zebrafish orthologs. Basal expression showed CYP1C1 and CYP 2Aa expression were observed in all eight tissues analyzed (liver, gill, intestine, kidney, spleen, brain, skin, and muscle). CYP 1A, and 1B1 expression was found in all tissues except for muscle and skin. However, CYP 2Y3 was expressed in liver, spleen, intestine and muscle whereas CYP 2 K in liver, kidney and intestine. 4 and 100 μg L−1 Benzo[a]pyrene (BaP) induced patterns showed that CYP 1A, 1B1 and 1C1 expression in liver, gill, and intestine was strongly up-regulated (p < 0.05). Furthermore, CYP 2Y3 was strongly induced in liver from BaP treatments (p < 0.05). The high induction on mRNA level of CYP1s and CYP 2Y3 by BaP could be associated with catalyzing detoxification and indicated that CYP2s may also be potential biomarker to screen AHR agonist. The high responsiveness of CYP1 and 2 genes suggested Chinese rare minnow is feasible to screen and assess pollution with AHR agonist.  相似文献   
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