【作者】 孙茵；

【导师】 王晓昌；

【作者基本信息】 西安建筑科技大学 ， 市政工程， 2007， 硕士

【摘要】 本文以西安市饮用水源水(黑河)、纳污河水(浐河)、城市景观水(大唐芙蓉园北湖和兴庆湖)以及污水厂二级出水(北石桥污水净化中心)为研究对象，采用不同地点、不同时间间断取样和长期定点连续取样的方法，用传统微生物学检测技术和分子生物学技术，分析包括埃希氏菌、粪大肠菌在内的病原菌在不同水体中的存在情况和分布规律。根据志贺氏痢疾杆菌、霍乱弧菌、沙门氏菌、埃希氏大肠菌四种病原细菌16S rRNA基因的高度保守性设计通用引物，建立起了用定量聚合酶链式反应技术(QPCR)快速检测地表水中病原细菌的方法，该方法能同时检测到包含上述四种病原菌的一大类病原微生物，检测限为25cfu／100mL。该方法快速灵敏，可将DNA提取、扩增、定量分析控制在数小时内完成(其中扩增分析可在2小时内完成)，为地表水病原微生物污染风险评价奠定基础。定量PCR检测结果与传统方法检测到的大肠菌群值表现出良好的相关性，回归分析表明，二者的相关系数为0.93。定量PCR结果为大肠菌群检测结果的2.2～5倍，是粪大肠菌群检测结果的16～34倍。根据地表水环境质量评价标准，结合粪大肠菌群检测结果及QPCR检测结果，对西安市典型地表水体进行微生物污染评价。结果发现，西安市黑河水属于Ⅰ类地表水，病原菌污染风险较小；北湖和兴庆湖属于Ⅱ、Ⅲ类地表水，满足景观娱乐用水A类水质要求，但在人类活动密集的时候，仍然有较高的病原菌含量。浐河水体，粪大肠菌指标可达Ⅱ类、Ⅲ类标准，但QPCR值较高，受其它病原菌污染风险较大；北石桥二级出水粪大肠菌群数在Ⅳ类、Ⅴ类水体中波动，QPCR值也显示出较高的病原菌污染风险。基于QPCR检测结果的病原菌污染评价标准还有待进一步研究。更多还原

【Abstract】 In order to make clear the pathogenic bacteria pollution characteristic of the surface water in the urban and suburb area of Xi’an city, we carefully chose five typical water body including 2 rivers, one of which is the source for urban water supply, 2 lakes and 1 secondary effluent of a domestic wastewater treatment plant. Samples were collected periodically and consecutively three times each month with the detection method covered both traditional cell culture technique and the quantitative polymerase chain reaction (QPCR) technique. Escherichia coli and fecal coliform were chosen as the indicator of fecal pollution with total bacterial as reference. The counts of these bacteria’s colony-forming units (CFU) were compared with measurements by QPCR method established by this study. The QPCR results were supposed as the indicator of other pathogenic bacteria pollution in water.For the QPCR method, we introduced a universal primer with Shigella dysenteriae, Vibrio cholerae, Salmonella typhrmurium, and Escherichia coli. as the reference strains. The universal primer was designed and synthesized according to the high conversation of 16S rRNA gene. Combined with QPCR technique, we make the sensibility of this new method up to 25cfu/100mL. What’s more, the accurate and sensitive measurements of these organisms can be obtained within several hours.Regression analyses and statistical comparisons of the MF culture and QPCR results showed that a positive correlation between the QPCR and Escherichia coli. with a strong correlation coefficient (r=0.93) can be seen. Besides, the QPCR results averaged 2.2-5 fold higher than the Escherichia coli. counts and 16-34fold higher than fecal coliform.Regarding different water samples, Heihe River of high quality as source water reached the Grade I surface water standard and was also quite safe according to QPCR results; Beihu Lake and Xingqinghu Lake could reach the Grade II or Grade III surface water quality standard, but there were higher health risk during the holidays when more people came for entertainment; Although Chanhe River receives industrial discharge, the fecal coliform counts were not very high, however, a very high QPCR may indicate the existence of large numbers of other pathogenic bacteria in the industrial discharge. The secondary effluent without disinfection was of high concentration of fecal coliform and much higher concentration of other pathogenic bacteria according to QPCR results.The current guidelines, based on MF results were unlikely to be applicable to QPCR results. More statistic documents should be collected to make a new guideline.更多还原