城市污水二级处理出水中沙门氏菌的PCR检测

建立了一种利用PCR检测城市污水二级处理出水中沙门氏菌的方法.采用膜吸附-洗脱法浓缩二级出水水样中的沙门氏菌,通过选用一对涵盖性和特异性均较强的引物139和141,对浓缩后的沙门氏菌进行PCR检测.利用正交试验法,对沙门氏菌PCR体系进行五因素四水平的试验,建立了沙门氏菌PCR的最佳体系.通过梯度PCR考察了退火温度对检测结果的影响,选择65℃作为退火温度,优化后沙门氏菌PCR体系的检测灵敏度可达0.314ngL.通过对已知细菌浓度的水样进行检测,确定了该法检测水样中沙门氏菌的灵敏度为2130CFUL.与传统MPN法的相比,该法在检测效果和检测效率上都优于MPN法.     

Eperimental study of photooxidation products of ethylbenzene

Smog chamber experiments were performed to investigate the composition of products formed from photooxidation of aromatic hydrocarbon ethylbenzene.Vacuum ultraviolet photoionization mass spectrometer and aerosol time-of-flight mass spectrometer were used to measure the products in the gas and particle phases in real-time.Experimental results demonstrated that ethylphenol,methylglyoxal,phenol,benzaldehyde,and 2-ethylfurane were the predominant photooxidation products in both the gas and particle phases.However,there were some differences between detected gas phase products and those of particle phase,for example,2-ethylfurane,ethylglyoxylie acid,nitroethylbenzene,3,4-dioxopentanal and ethyl-nitrophenol were only existing in the particle-phase.The possible reaction mechanisms leading to these products were also discussed and proposed.     

巷道内粉尘二次飞扬规律的数值模拟研究

针对巷道中沉积粉尘二次飞扬的现象,利用数值模拟的方法对粉尘二次飞扬进行了研究,分析了巷道内粉尘二次飞扬的极限风速与扬尘粒径之间的关系,从而为矿井通风除尘提供一定参考依据,给矿井工人创造良好的工作环境。     

Acute effects of chlorpyryphos-ethyl and secondary treated e uents on acetylcholinesterase and butyrylcholinesterase activities in Carcinus maenas

The acute effects of commercial formulation of chlorpyrifos-ethyl (Dursbanr®) and the secondary treated industrial/urban effluent (STIUE) exposure on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities in hepatopancreas and gills of Mediterranean crab Carcinus maenas were investigated. After 2 d of exposure to chlorpyriphos-ethyl, the AChE activity was inhibited in both organs at concentrations of 3.12 and 7.82 μ/L, whereas the BuChE was inhibited only at higher concentration 7.82 μ/L of commercial preparation Dursbanr®. The exposure of crabs to Dursbanr® (3.12 μ/L) showed a significant decrement of AChE activity at 24 and 48 h, whereas the BuChE was inhibited only after 24 h and no inhibition for both enzymes was observed after 72 h. Moreover, a significant repression of AChE activity was observed in both organs of C. maenas exposed to 5% of STIUE. Our experiments indicated that the measurement of AChE activity in gills and hepatopancreas of C. maenas would be useful biomarker of organophosphorous (OP) and of neurotoxic effects of STIUE in Tunisia.     

岩溶山区工业固体废弃物的二次水污染环境影响

中国岩溶山区每年都要产生大量的工业固体废弃物,这些工业固体废弃物在堆存过程中,主要由于降水的淋溶作用,引起了二次水污染现象,对地表地下水环境产生了很大影响。在建设项目环境影响评价工作中必须对此加以重视。     

宝成铁路5·12地震次生地质灾害特点及工程防灾

2008年5月12日四川汶川发生8.0级特大地震,受此影响,宝成铁路成都局管段沿线产生地震次生地质灾害,直接威胁到铁路运营的安全.通过对铁路沿线次生地质灾害的震后排查,总结了地震产生的灾害类型,分析了地震的致灾作用和影响地震次生灾害稳定性的因素,在此基础上结合实际,提出防灾工程建议,具有重要的现实意义.     

Changes of main secondary metabolites in leaves of Ginkgo biloba in response to ozone fumigation

To investigate the effect of elevated O3 on the accumulation of main secondary metabolites in leaves of Ginkgo biloba L., four-year-old trees were exposed in open-top chambers with ambient air and the air with twice ambient O3 concentration in Shenyang in 2006.Elevated O3 increased the concentrations of terpenes, but decreased the concentrations of phenolics in G.biloba leaves.The results showed that secondary compounds from G.biloba leaves responded to the elevated O3 exposure in a different way when compared to previous studies which showed elevated O3 increased the concentrations of phenolics but had no effect on the terpenes in leaves of other deciduous trees.Furthermore, reduced synthesis of phenolics may decrease the resistance of G.biloba to O3 and other environmental factors.On the other hand, the induced synthesis of terpenes may enhance the antioxidant abilities in G.biloba leaves at the end of O3 fumigation.     

紫外光-氯联用污水消毒削弱拖尾程度的实验研究

研究了紫外光-氯联用消毒工艺削弱二级出水氯消毒拖尾程度.考察了紫外光-氯使用顺序、pH、氯投量、紫外光剂量等因素对氯消毒大肠杆菌动力学曲线的影响.SS浓度对"拖尾现象"有显著影响,降低SS浓度能够有效提高拖尾区灭活率.紫外光-氯联用消毒能提高一级反应区的灭活速率1.08～1.25倍,并将拖尾区灭活率提高2～2.5个对数级,二者存在明显协同作用.UV/HOCl方式效果优于HOCl/UV方式.降低pH,提高氯投量将加快一级反应区消毒速度而更快进入拖尾区.紫外光剂量变化对拖尾区开始时间没有显著影响.     

Secondary organic carbon quantification and source apportionment of PM10 in Kaifeng, China

During 2005, the filter samples of ambient PM₁₀ from five sites and the source samples of particulate matter were collected in Kaifeng, Henan Province of China. Nineteen elements, water-soluble ions, total carbon (TC) and organic carbon (OC) contained in samples were analyzed. Seven contributive source types were identified and their contributions to ambient PM₁₀ were estimated by chemical mass balance (CMB) receptor model. Weak associations between the concentrations of organic carbon and element carbon (EC) were observed during the sampling periods, indicating that there was secondary organic aerosol pollution in the urban atmosphere. An indirect method of “OC/EC minimum ratio” was applied to estimate the concentration of secondary organic carbon (SOC). The results showed that SOC contributed 26.2%, 32.4% and 18.0% of TC in spring, summer-fall and winter, respectively, and the annual average SOC concentration was 7.07 μg/m³, accounting for 5.73% of the total mass in ambient PM₁₀. The carbon species concentrations in ambient PM₁₀ were recalculated by subtracting SOC concentrations from measured concentrations of TC and OC to increase the compatibility of source and receptor measurements for CMB model.     

Chemical composition and size distribution of secondary organic aerosol formed from the photooxidation of isoprene

Photooxidation of isoprene leads to the formation of secondary organic aerosol (SOA). In this study, the chemical composition of SOA formed from OH-initiated photooxidation of isoprene has been investigated with gas chromatography/mass spectrometry (GC/MS) and a home-made aerosol time-of-flight mass spectrometer. Sampling particles generated in a home-made smog chamber. The size distribution of SOA particles was detected by a TSI 3321 aerodynamic particle size spectrometer in real time. Results showed that SOA created by isoprene photooxidation was predominantly in the form of fine particles, which have diameters less than 2.5 m. The obtained mass spectra of individual particles show that products of the OH-initiated oxidation of isoprene contain methyl vinyl ketone, methacrolein, formaldehyde, and some other hydroxycarbonyls. The possible reaction mechanisms leading to these products were also discussed.