24孔板发酵法测定地表水和废水中粪大肠菌群的研究

对地表水和废水中粪大肠菌群的多管发酵法进行了改进。改进了初发酵方法,采用24孔板代替试管进行初发酵,复发酵方法保持不变。对环境中采集的23个污水样本采用24孔板初发酵法与多管发酵法进行比较,结果表明,两种方法相关性良好,两者在结果上无统计学意义的差别。采用改进的24孔板法进行初发酵有效节约了培养基、缩短了实验准备时间,简化了操作步骤,尤其适用于大批量的、污染严重的地表水和废水中粪大肠菌群的检测。     

地表水体中同时分析18种糖皮质激素方法的建立

建立了一种采用固相萃取-超高效液相色谱串极质谱联用系统(UPLC-MS/MS)同时测定地表水体中18种糖皮质激素的高灵敏分析方法.样品经过HLB固相萃取柱富集净化、V(乙腈)/V(乙酸乙酯)=1∶1,洗脱后,用UPLC-MS/MS测定.流动相为甲醇和0.1%乙酸水溶液(体积比),采用梯度洗脱,实现了18种目标物质的基线分离,线性范围为1.0~1 000μg·L-1.实际水样的加标回收率为65%~108%.整个分析的方法检出限(MDL)除醋酸可的松和醋酸氢化可的松为10 ng·L-1外,其他均在0.10 ng·L-1和1.0 ng·L-1之间.应用此方法于北京地表水体5个样品,检测到8种糖皮质激素,浓度范围0.20~476ng·L-1,其中曲安西龙、曲安奈德、醋酸氢化可的松和丙酸氯倍他索在地表水中首次检出,证明了该方法的有效性.     

Molecular approaches to microbiological monitoring: fecal source detection

Molecular methods are useful both to monitor natural communities of bacteria, and to track specific bacterial markers in complex environments. Length-heterogeneity polymerase chain reaction (LH-PCR) and terminal restriction fragment length polymorphism (T-RFLP) of 16S rDNAs discriminate among 16S rRNA genes based on length polymorphisms of their PCR products. With these methods, we developed an alternative indicator that distinguishes the source of fecal pollution in water. We amplify 16S rRNA gene fragments from the fecal anaerobic genus Bacteroides with specific primers. Because Bacteroides normally resides in gut habitats, its presence in water indicates fecal pollution. Molecular detection circumvents the complexities of growing anaerobic bacteria. We identified Bacteroides LH-PCR and T-RFLP ribosomal DNA markers unique to either ruminant or human feces. The same unique fecal markers were recovered from polluted natural waters. We cloned and sequenced the unique markers; marker sequences were used to design specific PCR primers that reliably distinguish human from ruminant sources of fecal contamination. Primers for more species are under development. This approach is more sensitive than fecal coliform assays, is comparable in complexity to standard food safety and public health diagnostic tests, and lends itself to automation and high-throughput. Thus molecular genetic markers for fecal anaerobic bacteria hold promise for monitoring bacterial pollution and water quality.     

FECAL COLIFORM SOURCE ASSESSMENT IN A SMALL,MIXED LAND USE WATERSHED1

ABSTRACT: This study presents the results of fecal coliform (FC) sampling in the Rawls Creek, South Carolina, watershed during 1999 and 2000. The work was undertaken because the watershed is listed on the 303(d) list for South Carolina due to FC excursions. The watershed is 43.8 percent residential, 35 percent forest, 5.7 percent mixed urban, 4.9 percent commercial, and 4.8 percent agriculture. Samples were taken at 15 stations during eight field trips divided into two phases to characterize FC inputs from subbasins and to integrate results from upstream sampling. FC concentrations ranged from 135 to 730 colonies/100 ml. Results suggest that retention ponds in the area are a significant factor in attenuation of FC concentrations. Catchments with the largest contiguous impervious areas are the greatest source of FC. The highest concentrations of FC were observed at stations just downstream from a large detention basin that intercepts storm runoff from a large commercial area. Further analysis of the design and performance of that structure is suggested. The Koon Branch tributary is less than 20 percent of the land area in the watershed but may contribute 40 percent of the fecal loading. The results of this study confirm the importance of site assessments to aid understanding of nonpoint source pollution in complex watersheds.     

Predicting the Fate and Transport of E. coli in Two Texas River Basins Using a Spatially Referenced Regression Model1

Abstract: The two main rivers of southeast Texas: Guadalupe and San Antonio have shown high temporal increase in bacteria concentration during the last decade. The SPAtially Referenced Regression On Watershed (SPARROW) attributes model, developed by the U.S. Geological Survey (USGS), has been applied to predict the fluxes and concentrations of contaminants in unmonitored streams and to identify the sources of these contaminants. This model identifies every reach as a basic network unit to distribute the sources, delivery, and attenuation factors. The model is data intensive and implements nonlinear regression to solve the parsimonious relations for describing various watershed processes. This study explored watershed and hydrological characteristics (land uses, precipitation, human and animal population, point sources, areal hydraulic load and drainage density, etc.) as the probable sources and delivery mechanisms of waterborne pathogens and their indicator (Escherichia coli [E. coli]) in the Guadalupe and San Antonio River basins. The effect of using various statistical indices for model selection on the final model’s ability to explain the various E. coli sources and transport processes was also analyzed.     

Occurrence and infection risk of waterborne pathogens in Wanzhou watershed of the Three Gorges Reservoir, China

The Three Gorges Reservoir (TGR), formed by China’s Yangtze Three Gorges Project, is the largest lake in the world, but there is too little information available about fecal contamination and waterborne pathogen impacts on this aquatic ecosystem. During two successive 1-year study periods (July 2009 to July 2011), the water quality in Wanzhou watershed of the TGR was tested with regard to the presence of fecal indicators and pathogens. According to Chinese and World Health Organization water quality standards, water quality in the mainstream was good but poor in backwater areas. Salmonella, Enterohemorrhagic Escherichia coli (EHEC), Giardia and Cryptosporidium were detected in the watershed. Prevalence and concentrations of the pathogens in the mainstream were lower than those in backwater areas. The estimated risk of infection with Salmonella, EHEC, Cryptosporidium, and Giardia per exposure event ranged from 2.9 × 10 -7 to 1.68 × 10-5 , 7.04 × 10-10 to 2.36 × 10-7 , 5.39 × 10-6 to 1.25 × 10-4 and 0 to 1.2 × 10-3 , respectively, for occupational divers and recreational swimmers exposed to the waters. The estimated risk of infection at exposure to the 95% upper confidence limit concentrations of Salmonella, Cryptosporidium and Giardia may be up to 2.62 × 10-5 , 2.55 × 10-4 and 2.86 × 10-3 , respectively. This study provides useful information for the residents, health care workers and managers to improve the safety of surface water and reduce the risk of fecal contamination in the TGR.     

南方某城市地表水体中粪源性污染指示微生物的分布特征研究

随着城市居民亲水娱乐活动日益增加,研究城市地表水体的粪源性微生物污染特征,开展人体健康风险评价,并以此为基础开展有效的水质监测和风险管理,对于人口密集的城市区域尤为重要.以我国南方某城市的5个典型地表水体为案例,监测总大肠菌（TC）、粪大肠菌（FC）、大肠埃希氏菌（EC）和肠球菌（ENT）这4种粪源性污染指示微生物以及常规理化水质指标,研究指示微生物在城市地表水体中的浓度水平、时间和空间分布特征以及不同水质指标之间的相关性.结果表明,案例水体中TC和FC通常在10^3～10^7个.L^-1,EC和ENT通常分别低于200个·L^-1和105个·L^-1;4种指示微生物的浓度分布呈现季节变化特征,并且能够指示水体受到周边环境的污染状况;4种指示微生物指标之间以及微生物指标与常规理化水质指标（如溶解氧等）之间具有一定的相关性.     

重庆市河水中粪源微生物污染特征及源解析

以重庆主要河流水体作为研究对象,使用传统培养技术评估了细菌总数、粪链球菌、肠球菌、脆弱拟杆菌、总大肠菌群及粪大肠菌群的污染水平;同时以拟杆菌作为特异性指示菌,选取人源性粪便专一指示菌引物（HF183）和猪源性粪便专一指示菌引物（Pig-2-Bac）进行源追踪.微生物培养结果表明：重庆市主要河流在春季有15.4%的研究断面未达到Ⅲ类水质,秋季有61.5%的研究断面未达到Ⅲ类水质.在春季,主城区河流主要受人类粪便污染,区县河流主要受动物粪便污染;在秋季,主城区和区县河流都主要受人类粪便污染.指示微生物指标间Pearson相关性分析结果表明粪链球菌、粪大肠菌群、肠球菌两两之间有显著相关性,肠球菌与脆弱拟杆菌有显著相关性.猪源性拟杆菌特异性生物标记Pig-2-Bac和人源拟杆菌特异性生物标记HF183对人和动物粪便污染区分成功率达100%;用这两种特异性引物对春季水样DNA进行扩增,发现13个采样点均未受到猪源粪便污染,唐家沱、朝天门、鸡冠石、合川受到人源粪便污染.     

罗源湾海水中粪大肠菌群的来源及空间分布

2002年1月到2005年12月通过多种方式对罗源湾海水中的FCB(粪大肠菌群)数量、来源及空间分布进行了调查.结果表明:湾内主要水域FCB的数量在<0.02～≥24 /mL之间,入海河流、沿岸居民的生活和农业生产活动以及海上网箱养殖是罗源湾海水中FCB的主要来源,其中湾内主要的入海河流FCB超标严重,入海河流是罗源湾内FCB污染的最主要来源.罗源湾内 FCB空间分布与盐度呈负相关(R2=0.84),空间分布表现为,西高东低、内腹海区高于湾口,近岸海区高于湾中央海区,表层高于底层,网箱养殖区高于非网箱养殖区,松山垦区由于受到河流入海的影响成为罗源湾内污染最严重的海区.     

金刚石膜电极消毒处理医院污水的试验研究

以掺硼金刚石(BDD)作电极的自制电解槽装置处理医院污水的消毒效果。在全回流处理模式下消毒处理医院废水,采用多管发酵法测定粪大肠菌群数。掺硼金刚石(BDD)作电极,在电极间距为2mm、医院污水Cl-浓度为200mg/L、pH值在7.0～8.0范围内、电流密度8mA/cm2、接触时间≥9s的条件下,对医院污水粪大肠菌群的去除率最佳,出水满足《医疗机构污水排放标准值》粪大肠菌群数均不得超过500MPN/L。掺硼金刚石(BDD)作电极的自制电解槽装置处理医院污水不需要添加化学药剂,对粪大肠菌群消毒效果好。