中华鳖出血性肠炎的药物防治研究

对由实验定筛选的中华鳖出血肠炎病病原菌的最佳防治药物为本正交试验的第6组,即A2B3C1,其抑菌圈达21.5mm.临床应用中采用中西结合复方制剂,即用第6组试验药物再加上中药白头翁汤(加减),其疗效更佳.     

Determination of 16 polycyclic aromatic hydrocarbons in water using fluorinated polyaniline-based solid-phase microextraction coupled with gas chromatography

The study on the performance of a fluorinated polyaniline (PANI) as a fiber coating for solid-phase microextraction (SPME) had been reported and 16 polycyclic aromatic hydrocarbons (PAHs) were selected to evaluate the performance of this fiber. Various parameters including sample volume, extraction temperature, time of desorption and extraction, pH and ionic strength were investigated intensively. A direct comparison between PANI-SPME fiber and commercial fiber was conducted. The results showed that the PANI-SPME coating had high affinity towards target compounds and the proposed method was successfully applied for the detection of real samples: rainfall and Taihu Lake water collected from Southern China. The whole PANI-SPME-GC method offers acceptable accuracy, precision and sensitivity and low detection limits, which is applicable to monitor trace levels of PAHs in real water bodies.     

Molecular detection of three gastroenteritis viruses in urban surface waters in Beijing and correlation with levels of fecal indicator bacteria

To assess the presence of three gastroenteritis viruses responsible for human acute gastroenteritis in surface water, a 1-year study was carried out in the city of Beijing, China. A total of 108 urban surface water samples were collected from nine collection sites which were defined with a global positioning system in rivers or lakes from September 2006 to August 2007. The water samples were subjected to virus concentration using an HA electronegative filter, followed by polymerase chain reaction (PCR) for rotavirus (RV) astrovirus (AV), and norovirus (NV). It showed that the number of viruses detected in water samples from different sites was variable, totaling 63 virus strains, with rotavirus (48.1%) verified as the most prevalent detected, followed by astrovirus (AV, 5.6%), and norovirus (NV, 4.6%). RV was also quantified by real-time PCR and the concentration of RV ranged from 0 to 18.27 genome copies·L(-1). And the distributions of RV in surface water were abundant in cold weather (from September to February) while less prevailing in warm weather (from March to August). The high detection rate of RV we encountered in this study provided convincing evidence that RV circulated at a certain frequency in the Beijing population. There was no statistically significant correlation between RV levels and both fecal coliform (R (2)?=?0.02) and Enterococcus faecalis (R (2)?=?0.02) densities. Our study suggests prolonged virus persistence in aquatic environments and emphasizes the enteric virus group as the most reliable for environmental monitoring.     

南京市地铁车站氡浓度水平的初步调查

采用静电收集氡子体法对南京市地铁车站环境中氡浓度进行了调查,初步掌握了南京市地铁站重点区域的氡浓度放射性水平,按照联合国原子辐射效应科学委员会推荐的评价方法估算氡浓度对地铁内工作人员人均年有效照射剂量。对地铁站新建和扩建项目的机械通风设计,为工作人员和公众的内照射剂量水平估算等提供依据。     

Measurement of the proximity effect for indoor air pollutant sources in two homes

Personal exposure to air pollutants can be substantially higher in close proximity to an active source due to non-instantaneous mixing of emissions. The research presented in this paper quantifies this proximity effect for a non-buoyant source in 2 naturally ventilated homes in Northern California (CA), assessing its spatial and temporal variation and the influence of factors such as ventilation rate on its magnitude. To quantify how proximity to residential sources of indoor air pollutants affects human exposure, we performed 16 separate monitoring experiments in the living rooms of two detached single-family homes. CO (as a tracer gas) was released from a point source in the center of the room at a controlled emission rate for 5-12 h per experiment, while an array of 30-37 real-time monitors simultaneously measured CO concentrations with 15 s time resolution at radial distances ranging from 0.25-5 m under a range of ventilation conditions. Concentrations measured in close proximity (within 1 m) to the source were highly variable, with 5 min averages that typically varied by >100-fold. This variability was due to short-duration (<1 min) pollutant concentration peaks ("microplumes") that were frequently recorded in close proximity to the source. We decomposed the random microplume component from the total concentrations by subtracting predicted concentrations that assumed uniform, instantaneous mixing within the room and found that these microplumes can be modeled using a 3-parameter lognormal distribution. Average concentrations measured within 0.25 m of the source were 6-20 times as high as the predicted well-mixed concentrations.     

杭州城区春节PM2.5中水溶性离子在线观测

利用大气细颗粒物水溶性组分在线连续监测分析系统(AIM-URG9000D),考察了杭州城区春节期间PM2.5中无机水溶性离子的浓度变化范围,探讨了这些离子的日变化特征和影响因素,同时分析了集中燃放烟花爆竹对水溶性离子浓度的影响。结果表明,SO2-4、NO-3、NH+4是PM2.5中水溶性离子的主要成分,分别占全部水溶性组分的33.3%、28.4%、19.4%;强致癌物质NO-2浓度为2.07μg/m3,远大于膜采样结果;NO-3与SO2-4的质量比为0.85,表明机动车尾气排放导致的大气污染正逐步加重;各水溶性离子有着各自不同的日变化规律。相关性分析表明,NH+4与NO-3、SO2-4的相关系数分别为0.92、0.81;K+、Cl-、Mg2+3者之间的相关系数均在0.9以上。烟花爆竹燃放期间,PM2.5浓度急剧上升,Cl-、SO2-4、K+、Mg2+浓度分别达到燃放前的18、6、53、76倍。     

底质农残测定中固相柱净化体系的选择

使用固相柱对底质中的7种农残进行净化。结果表明,在相同淋洗条件下,使用氟罗里硅土柱比硅胶柱净化效果好。比较了不同溶剂体系、不同溶剂配比下2种萃取柱的净化效果,选择乙醚-正己烷(体积比1∶2)或丙酮-正己烷(体积比1∶4)作为净化溶剂,较小的收集体积都可满足所有目标化合物的回收率要求;相比较而言,丙酮-正己烷(体积比1∶4)作为净化溶剂,洗脱液的杂质干扰更小,净化效果更好。使用氟罗里硅土柱和丙酮-正己烷(体积比1∶4)对样品净化,方法简单,快速,净化效果好,适合大批量底质样品的前处理净化过程。     

污染源水质COD在线仪器比对监测

比较了几种现场应用较多的水质COD在线监测分析与实验室分析方法在原理、方法等方面的主要差异,针对比对过程中存在的实际问题,提出了在样品采集、仪器原理选择、仪器定期校正等方面做好水质COD在线监测比对实验工作的建议。     

滇池浮游藻类群落构成调查

对滇池浮游藻类群落组成和空间分布开展了2次调查,鉴定出藻类8门66属159种及变种,绿藻种类最多,蓝藻次之。5、12月滇池全湖平均藻类密度分别为1.398×108、2.180×108个/升,蓝藻门微囊藻属为优势藻类。5月的调查中滇池外海藻类生物量呈北高南低的格局,而12月则呈现南部和中部高,北部低。外海的藻类生物量明显高于草海,草海藻类群落构成与外海明显不同,主要表现为绿藻门藻类所占比例较高。12月滇池外海及全湖藻类生物量都显著高于5月。与上一次(2006—2007年)滇池浮游藻类的系统调查相比,滇池(主要是外海)浮游藻类在物种数量、常见藻类、优势藻类及生物量水平方面与之接近。     

北京地区冬季典型PM2.5重污染案例分析

对2013年1月10—14日发生的持续性PM2.5重污染过程从污染过程演变、气象条件影响、与气态污染物关系、区域污染背景、PM2.5浓度空间分布演变及其与地面风场的关系、PM2.5组分特征等多个方面进行全面的分析,较为完整地还原了该次重污染案例的形成原因以及主要影响因素。主要结论包括:该次重污染过程是稳定气象条件下导致的局地污染物积累,再叠加华北区域性污染的影响共同造成,其中10、12日北京地区PM2.5浓度的快速增长反映了周边污染传输的显著影响;逆温不但造成污染物难以扩散,且不同的逆温类型对PM2.5浓度水平有显著影响,同时还发现逆温的破坏导致近地面高浓度污染物向上扩散,造成百花山出现峰值高污染浓度现象;NO2与PM2.5浓度水平的高相关性反映交通污染二次转化对PM2.5浓度水平的影响,在较高湿度条件下,SO2浓度水平对湿度敏感且表现为负相关性;该次污染过程中OM、SO2-4、NO-3、NH+4等组分在PM2.5质量浓度中的占比超过70%,说明燃煤、机动车等仍是北京地区最主要的污染来源,同时SO2-4占比最高也说明区域污染传输对该次重污染的显著贡献。