液氨泄漏事故树分析及风险预测

对液氨泄漏的原因进行了系统的归类,依此绘制了液氨泄漏事故树。分析得出,管理问题的基本事件结构重要度均要大于设备故障的基本事件,对各基本事件提出了相应的防范措施。最后以甘肃某化肥厂液氨储罐为例,对事故树中管道破裂致液氨泄漏产生的危害范围进行了预测。     

景观富营养水体生态修复对浮游植物群落结构的影响

对以再生水为补给水源的北京稻香湖园林水系进行生态修复实验。通过对浮游植物群落和理化指标的分析,探讨浮游植物对生态修复的响应和修复效果。结果显示,生态修复实验实施后,TN、TP、COD和BOD5分别下降62.55%、66.42%、48.53%和40.95%,富营养程度明显降低;浮游植物密度和Chl-a含量分别下降86.1%和77.4%;Shan-non-Weaver物种多样性指数值从生态修复前低于2上升到2.74,且优势种群发生演替。相关分析表明:TP、PO4-P、pH与浮游植物密度呈极显著正相关(P(0.01);TN、NH4-N、NO2-N、COD和DO与浮游植物密度呈显著正相关(P(0.05);Chl-a含量与浮游植物密度呈极显著正相关(P(0.01)。浮游植物群落结构对城市富营养景观水系的生态修复措施表现出明显的响应。     

Role of water on the H-abstraction from methanol by ClO

The influence of a single water molecule on the reaction mechanism and kinetics of hydrogen abstraction from methanol(CH_3OH) by the ClO radical has been investigated using ab initio calculations. The reaction proceeds through two channels: abstraction of the hydroxyl H-atom and methyl H-atom of CH_3OH by ClO, leading to the formation of CH_3O + HOCl(+H_2O) and CH_2OH + HOCl(+H_2O), respectively. In both cases, pre-and post-reactive complexes were located at the entrance and exit channel on the potential energy surfaces. Results indicate that the formation of CH_2OH + HOCl(+H_2O) is predominant over the formation of CH_3O + HOCl(+H_2O),with ambient rate constants of 3.07 × 10-19 and 3.01 × 10~(-23) cm~3/(molecule·sec), respectively, for the reaction without water. Over the temperature range 216.7–298.2K, the presence of water is seen to effectively lower the rate constants for the most favorable pathways by 4–6 orders of magnitude in both cases. It is therefore concluded that water plays an inhibitive role on the CH_3OH + ClO reaction under tropospheric conditions.     

Preliminary investigation on cytotoxicity of fluorinated polymer nanoparticles

As well-known persistent organic pollutants(POPs), organofluorine pollutants such as perfluorooctane sulfonate(PFOS) have been proven to be bioaccumulated and harmful to health. However, toxicological assessment of organofluorinated nanoparticles, which have emerged as a novel tool for biomedical and industrial applications, is lacking, to the best of our knowledge. To assess the biological effects and health risk of fluorinated nanoparticles,trifluoroethyl aryl ether-based fluorinated poly(methyl methacrylate) nanoparticles(PTFEPMMA NPs) were synthesized with various fluorine contents(PTFE-PMMA-1 NPs 12.0 wt.%,PTFE-PMMA-2 NPs 6.1 wt.% and PTFE-PMMA-3 NPs 5.0 wt.%), and their cytotoxicity was investigated in this study. The in vitro experimental results indicated that the cytotoxicity of PTFE-PMMA NPs was mild, and was closely related to their fluorine(F) contents and Fcontaining side chains. Specifically, the cytotoxicity of PTFE-PMMA NPs decreased with increasing F content and F-containing side chains. After exposure to PTFE-PMMA NPs at a sublethal dose(50 μg/m L) for 24 hr, the phospholipid bilayer was damaged, accompanied by increasing permeability of the cell membrane. Meanwhile, the intracellular accumulation of reactive oxygen species(ROS) occurred, resulting in the increase of DNA damage, cell cycle arrest and cell death. Overall, the PTFE-PMMA NPs were found to be relatively safe compared with typical engineered nanomaterials(ENMs), such as silver nanoparticles and graphene oxide, for biomedical and industrial applications.     

浅谈油气开发与环境安全

文章分析了油气能源现状、油气开发与环境的关系、油气开发与环境安全的关系,油气开发中的环境保护对策与环境监理。得出:油气开发既要做到和谐生产,又要保护环境;在油气开发中,对环境有影响的应加大修复力度,采取相应的环境保护措施,确保有效、长效的环境保护目标。     

渭河上游一次致洪暴雨过程诊断分析

应用天气学原理和方法,对1996年7月26～28日甘肃东部（渭河上游）暴雨过程的天气形势和物理量场的详细分析,结果表明,这次致洪暴雨的发生与低层能量的积累、700hPa低涡切变和低空急流的形成有直接关系。     

城市污水水解-厌氧-微氧联合处理工艺

采用水解 -厌氧 -微氧联合处理工艺处理城市污水的研究结果表明 :在总 HRT不超过 8.5h(水解 2.5h、厌氧 4.0h、微氧2.0 h) ,平均温度为 19℃ ,进水COD浓度为300±50 mg/L时 ,总 COD和 SS的去除率分别可达75%和80%以上 .总出水COD、BOD、SS完全达到国家二级排放标准 .微氧单元对厌氧出水中残余有机物去除效果良好 ,HRT不超过 2h,DO控制在 0.2 mg/L～0.5mg/L左右 ,进水为150mg/L时 ,去除率可达 53%以上 .微氧污泥沉降性能良好 ,SVI=38.8ml/g.水解 -厌氧 -微氧工艺在突出低能耗的前提下 ,达到了较高的有机物去除率 ,与现有的城市污水处理工艺相比有一定的优越性 .     

Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment

Mercury (Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations (PNECs) for Hg(II) and methyl mercury (MeHg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5 × 10^-3 μg/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms, and their potential ecological risk should be respectively evaluated on the basis of mercury species.     

基于Ti/SnO_2阳极氧化法的典型染料废水电化学氧化规律

采用Ti/SnO2电极间接阳极氧化法处理直接深棕M和活性艳蓝KNR模拟染料废水,研究电解质种类、pH、电压、NaCl投加量及电解时间对其降解效果的影响;在最佳组合条件下,通过分析UV-Vis光谱以及降解过程中氮元素的存在形式,研究上述2种染料的降解规律。结果表明,在pH为3,电压20 V,NaCl投加量为2.5 g/L的条件下,电解30 min后,直接深棕M和活性艳蓝KNR的脱色率分别达到80%和95%,60 min后直接深棕M的COD去除率可达75%,活性艳蓝KNR的COD去除率达到90%;电解60 min后,直接深棕M的偶氮双键完全破坏,萘环和苯环结构被逐步降解,活性艳蓝KNR溶液电解2 min,其分子结构中的蒽醌共轭体系被破坏,随反应的进行,蒽醌结构逐渐被破坏,染料逐步降解。     

城市居民CO2实时暴露特征与家庭个体差异

CO₂是室内空气质量的重要指标,然而有关居民个体CO₂实时暴露研究鲜有报道。为探究城市居民CO₂实时暴露特征与家庭个体差异,本研究以四川省32个城市居民家庭(111人)为研究对象,利用CO₂实时监测仪监测居民主要生活微环境(厨房、客厅、卧室、室外、办公室和车内)CO₂实时浓度,通过详细问卷调查获得居民24 h活动轨迹,绘制CO₂实时暴露曲线、分析家庭个体暴露差异、计算不同微环境对居民CO₂暴露贡献以及暴露强度。结果表明,13.5%的受试居民存在CO₂过度暴露风险(日均暴露浓度>1 000 mg·L^-1);所有受试居民均存在短期CO₂高浓度暴露风险,日内暴露于1 000 mg·L^-1以上浓度累计时长为5.4～11.2 h。受试居民CO₂暴露特征存在显著的家庭个体差异。日均暴露浓度与年龄呈正相关,并且存在性别差异。老年、中年和儿童的日均暴露浓度分别为(781±387)、(709±403)和(693±385) mg·L^-1。家庭成员中,男童日均暴露浓度高于女童,而中年和老年群体中女性日均暴露浓度均高于男性,控制卧室、客厅、车内和厨房微环境中的CO₂浓度可有效减少居民个体CO₂暴露风险。本研究为居民CO₂实时暴露风险研究和过高浓度暴露风险防控提供参考数据。