Impact of disinfection on drinking water biofilm bacterial community

Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination.     

移动通信基站后向电磁场分布规律研究

采用实地监测的方法,对成都市肿瘤医院、双流小坝村、商汇大厦、成渝收费站及农机研究院5个基站天线后向场进行测试,分析研究其后向场的分布规律。研究结果表明,基站产生的电磁辐射功率密度与天线的距离呈反比;基站后向场电磁辐射安全防护距离为0．5m,大于此距离的区域,基站产生的电磁辐射功率密度小于《电磁辐射防护规定》及《电磁辐射监测仪器和方法》规定的0．08W／m^2的公众限值。     

Size distribution and chemical characteristics of particles from crop residue open burning in North China

Crop residue open burning is an important emission source of ambient particles in China. This study analyzed the particle emission characteristics of crop residue open burning through combustion experiments with a novel open combustion simulation device using three typical crop straws in north China (corn, wheat, and rice). Particle samples size ranging from 0.006–9.890 µm were collected by an Electrical Low Pressure Impactor plus, a high size-resolution instrument capable of dividing particles into 14 size stages. The size distributions of organic carbon (OC), elemental carbon (EC), water-soluble ions, and elements were analyzed, and source chemical profiles were constructed for PM_0.1, PM₁, PM_2.5, and PM₁₀. The number concentration of particles was concentrated in the Aiken nuclei mode (0.006–0.054 µm), accounting for 75% of the total number, whereas the mass concentration was concentrated in the accumulation mode (0.054–0.949 µm), accounting for 85.43% of the mass loading. OC, EC, Cl^?, and K(include total K and water-soluble K) were the major chemical components of the particles, whose mass percentage distributions differed from those of other components. These five main components exhibited a bell-shaped size distribution in the 0.006–9.890 µm range, whereas the other components exhibited a U-shaped distribution. Among the chemical profiles for PM_0.1–PM₁₀, OC was the most important component at 10–30%, followed by EC at 2%–8%. The proportions of K⁺, Cl^?, and K varied substantially in different experimental groups, ranging from 0–15%, and K⁺ and Cl^? were significantly correlated (r = 0.878, α = 0.000).     

环保投资统计指标体系构建研究——以青岛市为例

文章在总结分析国内外环境保护投资统计指标的基础上,制定了环保投资统计指标构建原则;以青岛市为例,构建环保投资统计指标体系;并使用构建的指标体系统计分析了青岛市2014~2015年环保投资情况。结果表明,2014~2015年青岛市环保投资总额分别为86.30亿元、90.69亿元,其中,污染治理设施投资是环保投资的主要组成部分,占全市环保投资额度的一半以上。环保设施运行维护费用和生态环境保护投资次之,环境管理投资占比最低。     

2，4，6－三氯酚在土壤－小麦生态系统中的迁移、降解

用GC/ECD法测定土壤－小麦模拟生态系统中,2,4,6－三氯酚（TCP）浓度随时间的变化值,显示出TCP在土壤中的半衰期为3天,在小麦中的半衰期为8天。实验周期以后,土壤、小麦中未检出TCP残留物。假设TCP在系统中的迁移、降解遵循一级动力学过程,用二室系统模型预测了该土壤－小麦系统,土壤和小麦中TCP浓度随时间的变化值,比较TCP浓度的预测值与实验值,说明此模型是可靠的。实验结果为经天津土地处理系统处理后污水的安全回用,提供了科学依据。     

加油站在线监控系统简述与应用展望＊

加油站在线监控装置的正确安装应用是提高油气回收设备正常运行的重要保障,同时也是油气污染控制的有效保证。文章对目前世界上主要在线监控系统进行简述,对美国、德国、中国三国加油站在线监控系统进行分析比较,同时结合上海试点在线监控系统的应用情况和出现的问题,提出了对在线监控系统的应用展望。     

三丁基锡在水-脂质体间的分配行为

测定了不同酸度条件下三丁基锡(TBT)的正辛醇-水分配系数,并用卵磷脂自行制备脂质体代替正辛醇研究了TBT在人工合成生物膜-水间的分配行为.结果表明TBT在正辛醇和脂膜中的分配均随pH的增大而增大.但将二者进行比较,发现在pH＞pK_a时,TBT在二者中的分配比很接近,此时是疏水性TBTOH占优势;但在低pH下,TBT⁺是主要存在形态,其在脂膜中的分配量要大于在正辛醇中的分配量,说明此时用正辛醇来模拟三丁基锡在生物膜中的分配是不合适的.对离子型有机金     

活性组分含量和复合载体对SCR催化剂脱硝活性的影响

采用浸渍法制备V2O5 - WO3/TiO2催化剂,研究了活性组分WO3和V2O5含量对催化剂脱硝活性的影响.在催化剂载体中加入SiO2或Al2O3粉末,考察了复合载体对催化剂性能的影响.实验结果表明:适宜的WO3质量分数为10％,V2O5质量分数为0.50％;在催化剂载体中加入SiO2或Al2O3粉末,一定程度上降低...     

三峡库区消落带4种典型植物根际土壤养分与氮素赋存形态

三峡水库消落带土壤N循环受到植被覆盖和季节性淹水的影响,对三峡水库水质具有潜在的不利影响,进行消落带植被恢复和提高土壤N保持能力成为保护库区水环境的重要措施.选择三峡库区一级支流澎溪河消落带为研究对象,分别在冲积潮土、紫色土和水稻土分布区采集狗牙根、香附子、苍耳以及玉米这4种典型植物根际、非根际土壤,分析了根际与非根际土壤理化性质与N赋存形态特征,并比较了不同植物类型根际富集效果,初步探究不同植物根际效应对消落带土壤N循环的影响.结果表明,所有植物根际土壤p H均低于非根际,有机质、全氮、全磷、速效氮均高于非根际,且根际富集率表现为香附子狗牙根玉米苍耳;不同植物根际对土壤全钾、有效磷、速效钾影响作用不一致;植物根际土壤中可转化态氮TF-N及其不同赋存形态离子交换态氮(IEF-N)、碳酸盐结合态氮(CF-N)、铁锰氧化态氮(IMOF-N)和有机态和硫化物结合态氮(OSF-N)均高于非根际土壤,植物根际效应能够改变土壤N赋存形态及其对N循环的贡献率,但狗牙根和香附子根际土壤中TF-N占TN的比率低于非根际,而玉米和苍耳相反,表明消落带玉米和苍耳覆盖加快了N素向TF-N转化,不利于土壤N素保持;消落带土壤有机质、总磷和有效磷含量与可转化态N形态显著相关,是土壤N形态转化的主要因素.研究表明,消落带狗牙根和香附子覆盖对土壤N素的保持优于玉米和苍耳,植物根际效应对消落带土壤N循环的影响为消落带植被恢复中植物选择提供了参考.     

高效离子色谱法同时检测F-、CH3 COO-、HCOO-、C1-离子的方法研究

使用高效离子色谱法(HPIC),一次进样50μL,可在8分钟内完成F-、CH3COO-、HCOO-、Cl-检测;且能用同套系统梯度淋洗完成其他常规阴离子的检测.本文并从最佳洗涤条件的选择、主要影响因素、方法准确度、精密度,方法检出限等方面进行了研究与探讨.