Measurement of gas-phase total peroxides at the summit of Mount Tai in China

Measurement of ambient gas-phase total peroxides was performed at the summit of Mount Tai (Mt. Tai, 1534 m above sea level) in central-eastern China during March 22–April 24 and June 16–July 20, 2007. The hourly averaged concentration of peroxides was 0.17 ppbv (± 0.16 ppbv, maximum: 1.28 ppbv) and 0.55 ppbv (± 0.67 ppbv, maximum: 3.55 ppbv) in the spring and summer campaigns, respectively. The average concentration of peroxides at Mt. Tai, which is in a heavily polluted region, was much lower than hydrogen peroxide measurements made at some rural mountain sites, suggesting that significant removal processes took place in this region. An examination of diurnal variation and a correlation analysis suggest that these removal processes could include chemical suppression of peroxide production due to the scavenging of peroxy and hydroxy radicals by high NO_x, wet removal by clouds/fogs rich in dissolved sulfur dioxide which reacts quickly with peroxides, and photolysis. These sinks competed with photochemical sources of peroxides, resulting in different mean concentrations and diurnal pattern of peroxides in the spring and summer. A principal component analysis was conducted to quantify the major processes that influenced the variation of peroxide concentrations. This analysis shows that in the spring photochemical production was an important source of peroxides, and the major sink was scavenging during upslope transport of polluted and humid air from the lower part of the planetary boundary layer (PBL) and wet removal by synoptic scale clouds. During the summer, highly polluted PBL air (with high NO_x) was often associated with very low peroxides due to the chemical suppression of HO₂ by high NO_x and wet-removal by clouds/fogs in this sulfur-rich atmosphere, especially during the daytime. Higher concentrations of peroxides, which often appeared at mid-nighttime, were mainly associated with subsidence of air masses containing relatively lower concentrations of NO_y.     

污染防治微生物制剂在城市河流污染控制中的应用及其生物安全

简要论述了污染防治微生物制剂的概念和在城市河流污染控制中的应用,并介绍了国外对微生物制剂的风险评估和对污染防治微生物制剂的管理方式,提出了国内应优先开发本土的天然的污染防治微生物制剂的建议,尽快发展中国环境微生物技术.     

稻草制浆黑液生物＋混凝处理试验

通过对稻草制浆黑液厌氧、好氧、混凝处理组合工艺的试验研究，探索该工艺的可行性，考察了不同温度、不同有机负荷下，该类废水的生物处理效果以及后续混凝效果。结果表明：中温35℃是厌氧阶段最佳处理温度，好氧阶段不同负荷条件下，CODCr去除率基本相同；经厌氧－好氧处理，黑液CODCr和木质素去除率分别为80％和30％，色度去除不明显；混凝阶段CODCr和木质素去除率分别为70％和90％，色度去除率达90％以上，出水达到国家标准。     

NaCl和KCl对厌氧污泥抑制的动力学研究

在厌氧颗粒污泥和厌氧絮状污泥系统中,进行盐质量浓度(NaCl或KCl质量浓度,下同)对厌氧污泥抑制动力学的研究,得到不同拟合的COD降解动力学方程及参数.实验结果表明:当盐质量浓度为10～30 g/L时,KCl对厌氧污泥的COD比降解速率的抑制程度大于NaCl;当盐质量浓度由0 g/L增至10 g/L时,半速率常数逐渐增加;当盐质量浓度由10 g/L增至30 g/L时,半速率常数逐渐减小;在厌氧污泥系统中,NaCl抑制作用下的盐抑制常数高于KCl,且颗粒污泥的盐抑制常数高于絮状污泥.     

The endocrine disrupting potential of sediments from the Upper Danube River (Germany) as revealed by in vitro bioassays and chemical analysis

Introduction  

The present study was part of a comprehensive weight-of-evidence approach with the goal of identifying potential causes for the declines in fish populations, which have been observed during the past decades in the Upper Danube River.     

云南近百年来温度雨量的变化特征分析

用气候倾向率、Morlet小波方法,对云南10个站1901-2007年的年降水和平均温度资料分析表明:100年来云南平均增温速率为0.031℃/10a。近50年来全省平均增温速率为0.242℃/10a,略高于全国的增温,增温最大的是滇中的昆明、滇南的普洱,分别为0.442℃/10a和0.409℃/10a,并且西部明显高于东部。100年来云南年降水呈减少趋势,平均速率为7.288mm/10a,近50年来,年降水量减少平均速率为6.66mm/10a。但云南降水的区域分异非常明显,云南的东部、中部降水减少;而滇西北和滇东南地区降水增加。云南气温明显的年代际变化是32年,发生了3次突变。年降水呈明显的年代际及年际振荡,具有16～32年、4～8年周期。     

Environmental copper: Behaviour when involved in physical adsorption at several interfaces

From a literature-based assessment of the current knowledge about both the toxic or salutary properties of copper, this study focused on the determination, at 25 °C, of the interfacial properties of CuCl_2, either alone or in mixture with carbofuran used, here, as a model of organics and/or pesticide. The interfaces under study were: i) the air/solution interface and ii) the silica/solution interface. The former is considered as a path for volatilization, whereas the latter permits a modelling of physical adsorption upon solids, which is the first and unavoidable step in any adsorption process. One should note that it can also mimic adsorption on some sandy soils. Coadsorption was clearly identified as implicated in an enhancement of the surface content of both solutes at both interfaces. However, at the two interfaces under study, the way the surface became structured led to opposite adsorption mechanisms for the organic compounds and the salt. A rough theory about ionic adsorption is also proposed.     

Characterisation of particulate exposure during fireworks displays

Little is known about the level and content of exposure to fine particles (PM_2.5) among persons who attend fireworks displays and those who live nearby. An evaluation of the levels of PM_2.5 and their elemental content was carried out during the nine launches of the 2007 Montréal International Fireworks Competition. For each event, a prediction of the location of the firework plume was obtained from the Canadian Meteorological Centre (CMC) of the Meteorological Service of Canada. PM_2.5 was measured continuously with a photometer (Sidepak?, TSI) within the predicted plume location (“predicted sites”), and integrated samples were collected using portable personal samplers. An additional sampler was located on a nearby roof (“fixed site”). The elemental composition of the collected PM_2.5 samples from the “predicted sites” was determined using both a non-destructive energy dispersive ED-XRF method and an ICP-MS method with a near-total microwave-assisted acid digestion. The elemental composition of the “fixed site” samples was determined by the ICP-MS with the near-total digestion method. The highest PM_2.5 levels reached nearly 10 000 μg m^?3, roughly 1000 times background levels. Elements such as K, Cl, Al, Mg and Ti were markedly higher in plume-exposed filters. This study shows that 1) persons in the plume and in close proximity to the launch site may be exposed to extremely high levels of PM_2.5 for the duration of the display and, 2) that the plume contains specific elements for which little is known of their acute cardio-respiratory toxicity.     

混凝剂品种对混凝-超滤联合工艺膜污染的影响

本实验以工业化学合成聚合硫酸铁混凝剂和自制生物聚合硫酸铁为例,考察了铁系混凝剂品种对地表水浊度、TOC和UV254的去除效果,混凝剂品种对混凝-超滤联合工艺处理地表水过程中超滤膜污染的影响。混凝实验结果表明,在10 mg/L(以Fe3+计)最佳投加量下,两类混凝剂对浊度、TOC和UV254的去除率基本相同。超滤膜污染实验结果表明,生物聚合铁预处理水样通量衰减速度略大于化学聚合铁预处理水样;膜污染阻力分析结果显示,随着循环次数的增加,工业化学合成聚合铁预处理水样造成的不可逆污染阻力逐渐增加,而生物聚合铁预处理水样造成的不可逆污染阻力却略有下降;膜污染机理分析表明,2组过滤过程的膜污染类型基本相似,由最初的膜孔堵塞过渡到最终的滤饼层污染。SEM分析表明,生物聚合铁预处理水样的膜污染较为严重。     

2株苯胺降解的分离鉴定及其降解特性研究

从处理印染废水的活性污泥中分离得到2株苯胺降解菌,从菌落、细胞形态、生理生化及16S rRNA基因扩增测序等方面对2株菌进行了鉴定,并比较分析2株菌在好氧与缺氧条件下的苯胺降解、偶氮染料脱色及苯胺脱氨氧化酶基因tdnQ和黄素还原酶基因(fre)的携带情况.结果表明,2株菌属于Pseudomonas属和Shewanella属,分别命名为Pseudomonas sp.AN30和Shewanella sp.DN425.AN30菌株在振荡好氧条件下72h内对250mg/L苯胺的降解率为96.1%,DN425菌株的降解率为13.8%;在静置缺氧条件下AN30菌株的苯胺降解率为39.6%,DN425菌株的降解率仅为8.6%.DN425菌株在静置缺氧条件下4h内可将初始浓度为50 mg/L的偶氮染料酸性大红彻底脱色,而AN30菌株对酸性大红不具有脱色能力.以总DNA为模板,分别用tdnQ基因和fre基因特异性引物进行扩增,2株菌均能扩增出大小分别为380bp和630bp左右的目标条带,显示2菌株均携带有苯胺脱氨氧化酶基因和黄素还原酶基因.