综合性医院污水与居民生活污水的生物性污染调查

在对哈尔滨市的综合性医院和居民生活排放的污水生物性污染调查中,选择细菌总数、大肠菌群、肠道致病菌(沙门氏菌、志贺氏菌)、肠道病毒、蛔虫卵作检测指标,结果两种污水各项指标经统计学检验均无明显差异。     

广州市城区污水微生物学调查

目的了解广州市城区排放的污水中的微生物污染状况。方法调查广州市越秀、东山、荔湾、海珠4区的居民区、医院、市场、饭店酒家下水道及河涌的5种类型的污水的细菌总数、大肠菌群数、肠道致病菌(沙门菌,志贺菌)、金黄色葡萄球菌4项指标。结果共检测95份水样,其细菌总数的几何均数为1.65×1010个/mL,范围为2.40×106~2.01×1013个/mL;大肠菌群数的几何均数为9.78×107个/L,范围为9.0×104~2.38×1010个/L;肠道致病菌检出率为13.68%(13/95),其中沙门菌为7.37%(7/95),志贺菌为6.32%(6/95);金黄色葡萄球菌检出率为8.42%(8/95)。5种不同类型的污水的平均细菌总数不一(F=12.488,P<0.05),其中饭店酒家、居民区的污水平均细菌总数较高,5种不同类型的污水的大肠菌群数及致病菌检出率之间的差异均无统计学意义(P>0.05)。结论广州市城区污水的细菌污染程度比较严重,生活污水与医院污水存在相同的危险性。建议政府应加快污水处理设施的建设。     

饮用水常规指示菌与介水传染病相关性研究

目的研究GB 5749—2006《生活饮用水卫生标准》中常规监测指示菌与介水传染病之间的相关性。方法从公共卫生科学数据中心获取2014年全国介水传染病发病数据和饮用水常规指示菌监测数据;采用主成分分析对全国22个省市常规指示菌合格率作排名和分级;对常规指示菌与介水传染病及常规指示菌间的相关性采用Spearman偏相关分析。结果在22个省市饮用水常规指示菌合格率分级中,黑龙江省、江苏省、北京市和河北省等级较高。枯水期间除总大肠菌群水平与副伤寒发病率呈正相关(P0.05)外,其他指示菌与疾病之间均无显著相关性;4种常规指示菌间均两两呈正相关(P0.05)。丰水期间除总大肠菌群水平与伤寒、副伤寒发病率呈正相关(P0.05)外,其他指示菌与疾病之间无显著相关性;除大肠埃希菌与菌落总数无显著相关性外,其他常规指示菌间两两呈正相关。结论 GB 5749—2006中的常规指示菌与介水传染病相关性并不显著,建议进一步进行常规指示菌与介水传染病相关性的定量研究及探寻新型指示菌。     

天津地区典型地表水细菌污染状况与水质指标相关性研究

目的了解天津地区典型地表水中指示菌、典型肠道致病菌及条件致病菌的污染状况及其与常规水质指标之间的相关性。方法分别于2012年8月(丰水期)和12月(枯水期),在天津地区海河主要支流(子牙河和北运河)、海河干流以及引滦河流域各选择3个采样点,分别对水样中的指示菌(菌落总数、总大肠菌群、粪大肠菌群、大肠埃希菌)、致病菌和条件致病菌(沙门菌、志贺菌、粪链球菌)以及水质常规理化指标(浊度、pH、水温)进行检测。结果按照GB/T 3838—2002《地表水环境质量标准》中对粪大肠菌群的要求,北运河中、下游,子牙河中游,海河干流中游为Ⅲ类水质,引滦河为Ⅰ类水质,其他断面为Ⅱ类水质。在丰水期北运河、子牙河、海河干流和引滦河的指示菌浓度高于枯水期,水温与菌落总数和总大肠菌群呈正相关关系,浊度与指示菌和沙门菌呈正相关关系,沙门菌和粪大肠菌群之间呈正相关关系。结论北运河、子牙河和海河干流受细菌污染较为严重;引滦河受细菌污染轻,适合作为水源水;温度和浊度对该地区水体微生物污染有初步指示作用。     

医院污水和生活污水生物性污染危害的对比分析

对医院污水和生活污水的生物性污染进行对比调查,结果两种污水的细菌总数、大肠菌群数、肠道致病菌检出率在同一季节内无明显差异,而且各季节之间三种指标也无明显的规律性和差异。作者指出医院污水只占生活污水的一小部分。故应做好两种污水混合后的统一治理。     

魔芋食品对便秘者肠道功能的影响

本文观察便秘者食用加魇芋精粉的食品前后肠道功能的变化。结果表明魇芋食品能增加平均每日粪湿重(相当于1g魇芋精粉增重11.4g)和粪便含水量。能缩短肠道运转时间和平均一次排便时间。肠道细菌总数基本稳定。需氧活菌数和厌氧活菌数增加,以双歧杆菌为指示菌的厌氧菌占优势。     

魔芋食品对便秘者肠道功能的影响

本文观察便秘者食用加魔芋精粉的食品前后肠道功能的变化。结果表明,魔芋食品能增加平均每日粪湿重(相当于1g魔芋精粉增重11.4g)和粪便含水量,能缩短肠道运转时间和平均一次排便时间。肠道细菌总数基本稳定,需氧活菌数和厌氧活菌数增加,以双歧杆菌为指示菌的厌氧菌占优势。     

我国北方地区湖泊和水库水源水微生物污染及指示菌初步研究

目的调查北方地区8个湖泊和水库丰水期和枯水期的微生物污染状况,分析水体卫生指示菌与肠道致病菌的相关性。方法分别于2010年丰水期(8—9月)和枯水期(11—12月),采集北方地区8个较大的湖泊和水库的水样,检测菌落总数、总大肠菌群、大肠埃希菌、肠球菌和致病菌(包括志贺菌、沙门菌、弧菌和大肠埃希菌O157:H7)。结果丰水期水样致病菌检出率为51.6%(16/31),高于枯水期的31.3%(10/32),丰水期致病菌的检出率高于枯水期,差异有统计学意义(χ~2=7.72,P=0.005)。与枯水期比较,丰水期水样中的菌落总数、总大肠菌群、大肠埃希菌和肠球菌浓度均较高,而合格率均较低,除总大肠菌群的浓度外,差异均有统计学意义(均P0.05)。二项logistic回归结果显示,菌落总数、总大肠菌群、大肠埃希菌、肠球菌的浓度与致病菌的检出率间均呈正相关性;在模型其他因素不变的情况下,随着4种指示菌检出浓度(对数值)的增加,致病菌检出的风险(OR值)随之上升,其中,丰水期为肠球菌每增加1个对数值,致病菌检出的风险增加最大(OR=1.702,95%CI:1.447～1.957),枯水期为总大肠菌群每增加1个对数值,致病菌检出的风险增加最大(OR=1.513,95%CI:1.337～1.689)。结论北方地区湖泊、水库的微生物污染严重,应加强防护;肠球菌与致病菌的相关性最强,是较好的致病菌指示微生物。     

辽宁省某市一级以上医疗机构污水消毒处理情况调查分析

目的了解辽宁省某市一级以上医疗机构污水消毒处理情况,找出薄弱环节,制定有针对性的措施,确保医疗机构污水经消毒后达到排放标准。方法根据医疗机构污水管理相关法律及标准,设计调查表,对该市99家一级以上医疗机构污水处理与排放、消毒管理情况及消毒效果监测等进行调查。结果医疗机构对污水进行消毒的单位数占调查总数的87.88%,消毒所使用的消毒产品索证率较低,含氯消毒剂投放浓度为30mg/L—50mg/L的仅占调查总数的15.66%,接触时间大于60分钟的仅占调查总数的45.31%,污水消毒效果监测工作不到位。结论医疗机构应当采取措施对污水进行消毒并保障消毒设施正常运转,建立健全消毒产品进货验收制度,做好消毒处理过程控制管理,加强污水消毒效果监测。     

湛江市区生活污水有机物和微生物污染调查

目的了解湛江市区酒楼、居民楼和城市污水有机物和微生物污染状况。方法在一年四季中,对4家酒楼、3幢居民住宅楼和4个城市污水排放口污水的水质进行有机物和微生物指标的监测和基本情况调查。结果在酒楼、居民楼和城市污水的监测项目超标率中,粪大肠菌群分别为100%、97.22%、100%,氨氮分别为6.25%、15.28%、22.92%,亚硝酸盐分别为2.08%、1.39%、0。酒楼>100 mg/L耗氧量检出率为1.04%;三类污水的>105个/ml细菌总数检出率分别为96.88%、95.83%、100%。硝酸盐均无超标。肠道致病菌均无检出。城市污水的氨氮超标率明显高于酒楼污水(P<0.01),居民楼污水和酒楼污水的亚硝酸盐超标率差异无显著性(P>0.05)。三类污水的>105个/ml细菌总数检出率、粪大肠菌群超标率两两比较差异均无显著性(P>0.05)。结论市区酒楼、居民楼和城市污水均存在粪大肠菌群的严重污染和氨氮污染,必须加强污水治理。     

污水微生物气溶胶对大气污染的研究

本文对曝气池、滴滤池和氧化塘三种常用的污水生物处理厂周围空气中微生物气溶胶产生、扩散、波及范围等进行了调查,提出了空气中微生物革兰氏阴性杆菌来源于污水的依据:大肠杆菌群落形成单位的数量随着离污水池距离增加而减少;不排放污水的对照池周围空气未发现革兰氏阴性杆菌。三种处理方法形成的微生物气溶胶作用不同,滴滤池的喷雾及曝气池的搅拌充气均产生大量污水气溶胶,在氧化塘平静的水面上即使产生气溶胶也是轻微的。     

Sampling of high amounts of bioaerosols using a high-volume electrostatic field sampler

For studies of the biological effects of bioaerosols, large samples are necessary. To be able to sample enough material and to cover the variations in aerosol content during and between working days, a long sampling time is necessary. Recently, a high-volume transportable electrostatic field sampler for collection of fine particles has been described. The aim of this study was to investigate whether this sampler can be used for collection of high amounts of authentic bioaerosols that can subsequently be used for biological analysis. The investigation was carried out at a biofuel plant in a straw storage room and in a boiler room over two seasons. The sampled dust was quantified in terms of mass and characterized regarding microbial components and compared with dust sampled by Gravikon and GSP samplers. For the electrostatic field sampler, a prefilter was used to remove large objects. The prefilter was characterized for particle penetration and this testing indicated that the prefilter did not remove particles up to 10 mum, and therefore respirable dust was sampled by the electrostatic field sampler. Using the electrostatic field sampler in the straw storage and in the boiler room, 330 and 315 mg dust (net recovery of the lyophilized dust) was sampled during a period of 7 days, respectively. The sampling rates of the electrostatic field samplers were between 1.34 and 1.96 mg dust per hour, the value for the Gravikon was between 0.083 and 0.108 mg dust per hour and the values for the GSP samplers were between 0.0031 and 0.032 mg dust per hour. The standard deviations of replica samplings and the following microbial analysis using the electrostatic field sampler and GSP samplers were at the same levels. The exposure to dust in the straw storage was 7.7 mg m(-3) when measured by the electrostatic field sampler and 11.8 mg m(-3) when measured by the GSP inhalable dust sampler. The quantity (amount per mg dust) of total fungi, Aspergillus fumigatus, total bacteria, endotoxin and mesophilic actinomycetes sampled by the electrostatic field samplers and the Gravikon samplers varied within the same season by a factor smaller than four. The quantities of some microbial components were higher in the dust collected with all samplers in March than in August. In conclusion, by using the electrostatic field sampler, it was possible to sample replicas of large authentic aerosol samples that can be used, e.g. biological analysis.     

Energy forest irrigated with wastewater: a comparative microbial risk assessment

In this study, risks for human infection associated with irrigation of municipal wastewater on short rotation willow coppice (Salix) were evaluated in three countries. The aim was also to determine the reduction of indicator organisms and pathogens in the treatment plants. Two of the field sites were chosen for further evaluation by QMRA (quantitative microbial risk assessment) applied to three scenarios: accidental ingestions of wastewater, exposure to aerosols and ingestion of groundwater. The risks of infection for bacteria (Salmonella), virus (rotavirus) and protozoa (Giardia, Cryptosporidium) were characterised as probability of infections per exposure and number of infections per year.     

Effect of the implementation of HACCP on the microbiological quality of meals at a university restaurant

A study was conducted to evaluate the microbiological quality, including total mesophilic counts and markers of bacteriological hygiene, as indicator of food safety of three categories of the most consumed meals in a university restaurant, before and after implementation of the HACCP system and personnel training. Cold gastronomy products, cooked warm-served products, and cooked cold-served products were tested for bacterial contamination. Throughout the experiment, 894 samples were examined for total counts of aerobic bacteria, counts of indicator organisms (coliform organisms and Escherichia coli) and pathogens (Staphylococcus aureus, Bacillus cereus, Salmonella spp., and Listeria monocytogenes). Implementation of the HACCP system, together with training in personnel hygiene, good manufacturing practices, and cleaning and sanitation procedures, resulted in lower aerobic plate counts and a lower incidence of S. aureus, coliform organisms, E. coli, and B. cereus, whereas Salmonella spp. and L. monocytogenes were not found in all samples studied. The microbial results of this study demonstrate that personnel training together with HACCP application contributed to improve the food safety of meals served in the restaurant studied.     

An in-use evaluation of an alcohol-based pre-surgical hand disinfectant.

OBJECTIVE: To determine whether alcohol hand disinfection is an effective alternative to traditional agents for the pre-surgical scrub. DESIGN: A prospective clinical trial of a 70% isopropanol pre-surgical hand disinfectant. SETTING: The operating room suites at two hospital sites in British Columbia. METHODS: Cases were selected to evaluate both short and longer procedures. The hand disinfectant was compared to agents in current use as surgical scrubs (4% chlorhexidine and 7.5% povidone-iodine). Surgical technique and glove use were not modified. Pre- and postoperative fingertip impression and "glove-juice" cultures were used to determine microbial burden, and hands were evaluated for skin integrity. RESULTS: There was no statistical difference between the microbial hand counts following use of the alcohol-based product or the current agents, for cases less than 2 hours' duration. Comparison of longer surgical cases revealed significantly better pre- and postoperative culture results with the alcohol hand rinse, but analysis of matched pairs showed no significant difference in microbial counts. The alcohol hand rinse was equivalent to the operative scrub in terms of skin integrity and user acceptability. CONCLUSION: An alcohol hand rinse was equivalently effective in reducing microbial hand counts as the traditional pre-surgical scrub, both immediately after hand disinfection and at the end of the surgical procedure.     

Studies on microbial quality of filtered water in households of a university community in Nigeria

Water samples from home filters in nine residential areas of a Nigerian university community were studied. The membrane filter technique was used to determine the total coliform and faecal coliform counts/100 ml of water. Most of the 100 samples studied were grossly contaminated with total coliform counts/100 ml ranging from 0-442, faecal coliform counts/100 ml, 0-216 and the total aerobic plate count per millilitre ranged from 3.0 X 10(3) to 1.9 X 10(9) c.f.u. The source (dams) of water, fitness of filter candles, frequency of cleaning candles and pH of water did not significantly (P greater than 0.05; chi2) affect the microbial quality of either filtered boiled or unboiled tap water. Escherichia coli type I was isolated from 17.9% of the faecal coliforms tested but from only 2.3% of total coliforms. Enterobacter aerogenes was most predominant (38.5%) amongst faecal coliforms isolated while Enterobacter cloacae was the most frequent (37.2%) of the total coliform isolates. The gross contamination of filtered water from all households sampled calls for an enlightenment of residents on the proper use of home water filters.     

Size distribution and speciation of chromium in paint spray aerosol at an aerospace facility

Spray painters are potentially exposed to aerosol containing Cr(VI) via inhalation of chromate-based paint spray. Two field studies were conducted at an aerospace facility to determine the size distribution and speciation of Cr(VI) in paint spray aerosol. Sampled paint products consisted of sparingly soluble strontium chromate in an epoxy resin matrix, a matrix generally known for its durability and toughness. Personal aerosol samples were collected using Sierra Marple personal cascade impactors and analyzed for Cr(VI) and total Cr. The size distribution of total Cr particles in the paint aerosol had a Mass Median Aerodynamic Diameter (MMAD) of 7.5 mum [Geometric Standard Deviation (GSD = 2.7 mum)] in both field studies. The MMAD of Cr(VI) particles was 8.5 mum (GSD = 2.2 mum). Particles >2 mum constituted 90% or more of the total Cr and the Cr(VI) mass, in all sampled paint aerosols and were lognormally distributed. The target site for respiratory deposition of Cr in the aerosol was estimated based on the mass distribution of Cr according to particle size. On an average, 62% of the Cr and Cr(VI) mass in the paint aerosol consisted of particles >10 mum. This study showed that 71.8% of Cr(VI) mass in paint spray aerosol potentially inhaled by a spray painter may deposit in the head airways region. Only 2.0 and 1.4% of Cr(VI) mass in the paint aerosol may potentially deposit in the alveolar and tracheobronchial region, respectively. The ratio of Cr(VI) mass to total Cr mass was determined in bulk paint and the data indicate that Cr was predominantly in the Cr(VI) valence state, before spraying. The ratio of Cr(VI) mass to total Cr mass was also determined in paint aerosol samples. The data indicated that there was a reduction of Cr(VI) regardless of Cr aerosol particle size. Cr(VI) reduction occurred most likely during the 8 h sample collection time period. These findings are in agreement with the findings that observed Cr(VI) reduction during collection of airborne Cr(VI) in samples of chromic acid mist. The use of Cr(VI) stabilizing sampling media and the storage of samples at lower temperatures (4 degrees C ) during and after sampling may avoid the underestimation of Cr(VI).     

Total and infectious Cryptosporidium oocyst and total Giardia cyst concentrations from distinct agricultural and urban contamination sources in Eastern Canada

Cryptosporidium and Giardia (oo)cyst concentrations are frequently used for assessing drinking water safety. The widely used USEPA Method 1623 provides total counts of (oo)cysts, but may not be accurate for human health risk characterization, since it does not provide infectivity information. The total counts and infectious fraction of Cryptosporidium oocysts and the total counts of Giardia cysts were assessed in major fecal pollution sources. Fresh calf and cow feces, their manure, and the discharge point were sampled in a small rural sub-watershed (n = 20, 21, 10, 10). Median concentrations for total (oo)cysts were higher in calves (333 oocysts g(-1); 111 cysts g(-1)) than in cows (52 oocysts g(-1); 7 cysts g(-1)). Infectious oocysts were found in 17 (7%) of the samples and none were found in manure or at the discharge point. Urban sources were sampled in the influent and effluent (n = 19, 18) of two wastewater treatment plants. Peak concentrations were 533 oocysts L(-1) and 9,010 cysts L(-1) for influents and 89 oocysts L(-1) and 472 cysts L(-1) for effluents. Infectious oocyst fractions varied from below the detection limit to 7-22% in the effluent and influent respectively. These infectious fractions are significantly lower than those currently used for quantitative microbial risk assessment estimates.     

Multiple indicator hidden Markov model with an application to medical utilization data

Monthly counts of medical visits across several years for persons identified to have alcoholism problems are modeled using two-state hidden Markov models (HMM) in order to describe the effect of alcoholism treatment on the likelihood of persons to be in a 'healthy' or 'unhealthy' state. The medical visits can be classified into different types leading to multivariate counts of medical visits each month. A multiple indicator HMM is introduced, which simultaneously fits the multivariate Poisson counts by assuming a shared hidden state underlying all of them. The multiple indicator HMM borrows information across different types of medical encounters. A univariate HMM based on the total count across types of medical visits each month is also considered. Comparisons between the multiple indicator HMM and the total count HMM are made, as well as comparisons with more traditional longitudinal models that directly model the counts. A Bayesian framework is used for the estimation of the HMM and implementation is in Winbugs.     

Studies on microbial quality of filtered water in households of a university community in Nigeria.

Water samples from home filters in nine residential areas of a Nigerian university community were studied. The membrane filter technique was used to determine the total coliform and faecal coliform counts/100 ml of water. Most of the 100 samples studied were grossly contaminated with total coliform counts/100 ml ranging from 0-442, faecal coliform counts/100 ml, 0-216 and the total aerobic plate count per millilitre ranged from 3.0 X 10(3) to 1.9 X 10(9) c.f.u. The source (dams) of water, fitness of filter candles, frequency of cleaning candles and pH of water did not significantly (P greater than 0.05; chi2) affect the microbial quality of either filtered boiled or unboiled tap water. Escherichia coli type I was isolated from 17.9% of the faecal coliforms tested but from only 2.3% of total coliforms. Enterobacter aerogenes was most predominant (38.5%) amongst faecal coliforms isolated while Enterobacter cloacae was the most frequent (37.2%) of the total coliform isolates. The gross contamination of filtered water from all households sampled calls for an enlightenment of residents on the proper use of home water filters.