Antioxidant responses to benzo[a]pyrene, tributyltin and their mixture in the spleen of Sebasticus marmoratus

It has been reported that there is an interaction between Benzo[a]pyrene （BaP）, a widespread carcinogenic polycyclic aromatic hydrocarbon, and tributyltin （TBT）, an organometal used as an antifouling biocide. This study was therefore designed to examine the potential in vivo influence of BaP, TBT and their mixture on splenic antioxidant defense systems of Sebastiscus marmoratus. The fish were exposed to water containing environmentally relevant concentrations of BaP, TBT and their mixture. Spleens were collected for biochemical analysis after exposure for 7, 25, 50 d and after recovery for 7, 20 d. Cotreatment with BaP and TBT for 7 d potentiated the induction of glutathione peroxidase （GPx） activity by BaP or TBT alone. The cotreatment for 25 and 50 d resulted in inhibition of GPx activity, which was similar to the effect of TBT. Splenic glutathione S-transferase （GST） activities were significantly elevated in S. marmoratus exposed to BaP starting from 7 d and remained high up to 25 d. However, no further activity change was found with prolonged exposure. Cotreatment of BaP and TBT primarily inhibited the GST activity, which was similar to the effect of TBT. Cotreatment with BaP and TBT for 25 or 50 d potentiated the depletion of GSH （glutathione） by BaP or TBT alone. MDA （malondialdehyde） contents in spleen of S. marmoratus were not significantly altered compared with the control during the test period. Spleen, as an immune organ, is sensitive to exposure of BaP or TBT. It should have an effective mechanism to counteract oxidative damage. Antioxidative defense systems in spleen of S. marmoratus should be considered as potential biomarkers. Short-term exposure of BaP or TBT could result in induction of antioxidant defense system. A significant decrease of these indices, such as GSH, GST, GPx might indicate more severe contamination.     

十溴二苯乙烷对蚯蚓亚急性毒性及微生物群落结构影响

新型溴系阻燃剂十溴二苯乙烷(DBDPE)生产和使用量日益增大,在环境中的检出率越来越高,其生态风险正受到广泛关注.然而,有关DBDPE对陆地无脊椎生物毒性效应以及微生物群落结构的影响知之甚少.探究了不同剂量(5、10、20、50和100mg·kg-1)DBDPE暴露对赤子爱胜蚓(Eisenia fetida)生长、行为...     

生物法同时脱硫脱硝试验研究

采用轻质陶粒生物滴滤塔处理摸拟燃煤烟气中二氧化硫和氮氧化物的试验研究,探讨生物法同时脱硫脱硝的影响因素及生物降解宏观动力学。研究结果表明,生物法能有效同时去除烟气中的二氧化硫和氮氧化物,烟气同时脱硫脱硝效率分别可达99.9%和88.9%。为获得最佳烟气同时脱硫脱硝效果,二氧化硫和氮氧化物进气负荷应分别＜140 g/（m³·h）和20 g/（m³·h）,循环液pH=7～8,空床停留时间为30.28 s,喷淋密度为8.81 L/（m³·h）。     

烟气同时脱硫脱硝化学反应的可能性分析

根据烟气气体组分情况,将可能发生的化学反应方程式进行筛选,确定独立反应个数。通过热力学计算得到了标准状态下热力学函数值,进而求得了不同温度下的热力学性质。通过标准生成自由焓、标准吉布斯自由能变、标准熵变的计算,分析了烟气同时脱硫、脱硝中发生化学反应的可能性,为烟气同时脱硫、脱硝动力学理论的研究打下了基础。     

吸附法烟气脱硫

燃油和煤炭在燃烧过程中会产生SO2 ,这些SO2 排入大气中 ,形成酸雨 ,严重破坏生态环境 ,危害人类健康。一个世纪以来 ,人们对烟气脱硫作出了很大的努力 ,但常见的脱硫技术具有投资大、运行费用高 ,甚至有二次污染等问题。吸附法烟气脱硫工艺简单、脱硫效率高 ,是一种具有深入研究价值与应用前景的方法     

The impact of pesticides on oxidative stress level in human organism and their activity as an endocrine disruptor

Pesticides cause serious environmental and health problems both to humans and animals. The aim of this review is to discuss selected herbicides and fungicides regarding their mode of action and their influence on basic oxidative stress parameters and endocrine disruption properties tested in selected cell cultures in vitro. Because of numerous difficulties which animal studies are subject to, cell cultures are an excellent experimental model reflecting human exposure to different pesticides through all relevant routes. This experimental model can be used to monitor aggregate and cumulative pesticide exposures.     

湿式烟气脱硫喷淋塔内部流场数值模拟研究

以300MW机组湿法烟气脱硫喷淋塔为研究对象,利用计算流体力学通用软件对其内部两相流场进行模拟。气相湍流由标准k 模型描述,喷淋液滴由拉格朗日颗粒轨道模型描述。预测了无喷淋和有喷淋2种条件下的气相湍流流场分布、沿塔高方向不同截面上的气速分布以及喷淋液滴的轨迹。模拟结果表明,引入喷淋液后,出口截面气速分布明显均匀化,其最大值由无喷淋时的12m/s降至6m/s。该最大值出现在靠近塔壁处,是由塔壁附近喷淋密度较低造成的,可通过改进周边喷嘴的布置方式及喷嘴型式进行优化。     

DBD结构对船用LNG发动机尾气CH4氧化脱除的影响

为提高等离子体氧化CH₄的脱除效率,同时避免放电过程中副产物NO_x的生成,在模拟天然气 (LNG) 发动机排气中,研究了介质阻挡放电 (DBD) 反应器电极结构参数对CH₄脱除效率、CO₂选择性及NO_x生成的影响及其机理。结果表明：增大电极直径使得气隙中折合场强E/N提高,增加了·O和·OH自由基的生成,促进了CH₄的氧化,提高了CO₂选择性;内电极直径的增大使E/N在气隙中分布更加集中,抑制了N₂(X, v)和N自由基的生成,减少了副反应的发生。与圆杆电极相比,螺纹电极的螺牙顶部附近具有过高的电场强度,从而促进N自由基的生成并抑制·O自由基的产生,故圆杆电极比螺纹电极具有更高的CH₄脱除效率及更低的NO_x生成。电极长度过长降低了折合场强以及电子平均能量,不利于氧化性活性粒子生成,导致CH₄脱除效率和CO₂选择性降低,同时增加了N₂(X,v) ,也使得NO_x增加。本研究可为提高低温等离子体协同催化剂促进甲烷还原NO_x系统的脱除效率,降低DBD反应器能耗提高能源利用率提供参考。     

Ca/S比小于1条件下半干半湿法烟气脱硫技术的研究

通过对煤中灰分、粉煤灰中碱性物质成分、含量的分析 ,证明在Ca/S小于 1的条件下进行半干半湿法烟气脱硫是可行的。阐述了粉煤灰中碱性物质被有效利用的条件为高温、高湿和高压 ,该条件可以通过蒸汽输送粉煤灰来实现。     

氧化锰共生矿烟气脱硫的机理及影响因素

利用南非的氧化锰共生矿进行烟气脱硫,研究了共生锰矿烟气脱硫性能及其机理,并考察了锰矿粒径、反应温度、液固比、进气流量、进口SO2浓度等因素对脱硫率的影响。结果表明,氧化锰共生矿中主要的锰化合物是MnO2、Mn2O3和MnCO3,烟气脱硫过程主要存在4种方式：MnO2与SO2发生氧化还原反应生成硫酸锰;液相中Mn2+催化氧化SO2产生硫酸;MnCO3与硫酸反应生成硫酸锰;Mn2O3与硫酸反应后生成的MnO2可以继续与SO2进行脱硫反应,但是Mn2O3与SO2直接反应的活性较差。氧化锰共生矿烟气脱硫的最佳工艺参数为：锰矿粒径200目、反应温度80 ℃、液固比10:1以及进气流量600 mL?min-1