Effect of natural aquatic humic substances on the photodegradation of bisphenol A

The photochemical degradation of bisphenol A (BPA) was studied in the presence of natural humic substances from different origins under simulated solar irradiation. BPA underwent insignificant direct photolysis in neutral water, but rapid photosensitized degradation in four humic substances solutions via pseudo-first-order reaction occurred. The photo-degradation rate of BPA was insensitive to the different initial BPA concentrations and was inhibited in aerated solution compared with the deoxygenated medium. The reactive oxygen species (ROS) such as ·OH and ¹O₂ produced from excitation of humic substances under irradiation was determined from the quenching kinetic experiment using molecular probe. The five main intermediate photoproducts of BPA in Nordic lake fulvic acid (NOFA) were tentatively identified using gas chromatography/mass spectrometer (GC/MS). Based on the identification of ROS and the analysis of photoproduct formation, the possible phototransformation pathways of BPA were proposed, involving the direct photolysis due to the energy transfer from the triplet state humic substance (³HS*) to BPA molecules and hydroxyl radical addition and oxidation as well. Translated from Acta Scientiae Circumstantiae, 2005, 25(6): 816–820 [译自: 环境科学学报]     

Chemical speciation and anthropogenic sources of ambient volatile organic compounds(VOCs)during summer in Beijing,2004

Volatile organic compounds (VOCs) were measured at six sites in Beijing in August, 2004. Up to 148 VOC species, including C₃ to C₁₂ alkanes, C₃ to C₁₁ alkenes, C₆ to C₁₂ aromatics, and halogenated hydrocarbons, were quantified. Although the concentrations differed at the sites, the chemical compositions were similar, except for the Tongzhou site where aromatics were significantly high in the air. Based on the source profiles measured from previous studies, the source apportionment of ambient VOCs was preformed by deploying the chemical mass balance (CMB) model. The results show that urban VOCs are predominant from mobile source emissions, which contribute more than 50% of the VOCs (in mass concentrations) to ambient air at most sites. Other important sources are gasoline evaporation, painting, and solvents. The exception is at the Tongzhou site where vehicle exhaust, painting, and solvents have about equal contribution, around 35% of the ambient VOC concentration. As the receptor model is not valid for deriving the sources of reactive species, such as isoprene and 1,3-butadiene, other methodologies need to be further explored.     

复合式绿化林带在港区边界噪声防治中的应用

通过理论及实际研究复合式绿化林带降噪效果，设想通过在港区边界种植复合式绿化林带来解决港区噪声超标的问题，同时起到保护和保持生态平衡的作用。     

炼油厂柴油碱洗废渣的分析

通过对炼油厂柴油碱洗废渣的分析，先后测定了碱渣的COD值、硫醇硫含量、碱度和含油量。测定结果表明。柴油碱渣中含浓度很高的恶臭物质和大量的有机物盐。为了进一步鉴定碱渣的成份，分别利用红外光谱和紫外光谱进行分析。结果显示，柴油碱渣中的恶臭污染物主要为硫醇硫、噻吩、酚、环烷酸、脂肪酸等酸性有机物。为废碱渣的处理提供了重要的依据。     

苏州河武宁路断面底泥需氧量的测定

对苏州河武宁路断面的底泥需氧量（SOD）进行了测定。结果表明，综合调水工程后，SOD首先经历了一个显著上升的过程，随后开始逐步下降，目前还处于不断变化的过程。其中，上覆水体的流态对SOD的影响很大；另外，随着水质改善，生物耗氧的权重可能还会增加。     

重庆市"十一五"污染物总量控制研究

选取了二氧化硫、化学需氧量和氨氮作为重庆市“十一五”期间主要的污染物总量控制指标,介绍了这几种污染物总量控制目标的测算方法,根据重庆市的有关规划以及环境保护的需要,测算出了“十一五”期间水污染物、大气污染物的总量控制目标,对“十一五”期间总量控制的实施提出了建议。     

金属离子介导活性氧引起DNA氧化损伤及机制研究

应用高效液相色谱 电化学检测技术 ,以及单细胞凝胶电泳技术 ,研究了 11种不同价态金属离子体外诱导核酸 (DNA)氧化损伤产生 8 羟基脱氧鸟苷和DNA链断裂的化学机制 .结果表明 ,能够氧化为高价态的金属离子如Fe2 + 、Cu2 + 、Cr3 + 等能够介导活性氧造成DNA的氧化损伤 ,介导能力呈现Fe2 + Cu2 + >Cr3 + 的顺序 .另外一些金属离子 ,如V3 + 、Ni2 + 、Cd2 + 、Zn2 + 、Co2 + 、Fe3 + 等 ,不能介导核酸氧化损伤形成 8 OH dG加合物及引发DNA断裂 ,但可能诱导核酸链交联的发生 .不同金属离子介导活性氧氧化DNA能力的差异是由其催化Fenton反应及与DNA结合能力的不同引起的     

灰色马尔柯夫模型在地表水体DO浓度预测中的应用

灰色马尔柯夫模型是一种随机预测模型，被广泛的应用于社会，经济的预测中，本文利用灰色马尔柯夫模型对某平原河段DO浓度进行了预测。经验证，灰色马尔柯夫模型适用于对地表水体DO浓度预测，并具有相当高的精度，在此基础上，作者提出了改进的建议，使模型更具有实用性和可操作性。     

黑钨矿的氧扩散动力学

在水压100 MPa,温度500~800℃和富18O水的热液条件下,开展了黑钨矿氧扩散动力学的实验研究。并由离子探针质谱测定平行于c轴和垂直于c轴的黑钨矿氧同位素扩散剖面。经实验研究获得了黑钨矿氧扩散的Arren ius关系。黑钨矿平行于c轴氧扩散的指数前因子D0为1.15×10-6cm2/s,扩散活化能Q为171.4±7.4 kJ/mol;垂直于c轴的氧扩散的指数前因子D0为8.51×10-7cm2/s,扩散活化能Q为170.8±7.8 kJ/mol。黑钨矿的氧扩散无明显方向性。黑钨矿的氧扩散交换封闭温度低于透辉石、角闪石和金红石,高于钙长石,与磁铁矿十分接近。     

快速测定法测定生化需氧量在环境监测中的应用

生化需氧量是指在规定条件下,微生物分解存在水中的某些可氧化的物质,特别是有机物所进行的生物化学过程中消耗溶解氧的量.目前对水体中的生化需氧量的测定除采用经典的稀释接种法外,已开始采用新方法,即微生物电极法.他能够在几分钟内测定水体的BOD含量,大大缩短了传统方法的五天培养时间,对于快速了解水体的有机污染状况,具有积极地的意义.