Water quality at points-of-use in the Galapagos Islands

Piped drinking water is often considered a gold standard for protecting public health but research is needed to explicitly evaluate the effect of centralized treatment systems on water quality in developing world settings. This study examined the effect of a new drinking water treatment plant (DWTP) on microbial drinking water quality at the point-of-use on San Cristobal Island, Galapagos using fecal indicator bacteria total coliforms and Escherichia coli. Samples were collected during six collection periods before and after operation of the DWTP began from the freshwater sources (n = 4), the finished water (n = 6), and 50 sites throughout the distribution system (n = 287). This study found that there was a significant decrease in contamination by total coliforms (two orders of magnitude) and E. coli (one order of magnitude) after DWTP operation began (p < 0.001). However, during at least one post-construction collection cycle, total coliforms and E. coli were still found at 66% and 28% of points-of-use (n = 50), respectively. During the final collection period, conventional methods were augmented with human-specific Bacteroides assays – validated herein – with the goal of elucidating possible microbial contamination sources.Results show that E. coli contamination was not predictive of contamination by human wastes and suggests that observed indicator bacteria contamination may have environmental origins. Together these findings highlight the necessity of a holistic approach to drinking water infrastructure improvements in order to deliver high quality water through to the point-of-use.     

Microbial quality of water in rural communities of Trinidad.

A cross-sectional study was conducted in four rural communities of northeastern Trinidad to determine the microbial quality of water supply to households and that quality's relationship to source and storage device. Of the 167 household water samples tested, total coliforms were detected in 132 of the samples (79.0%), fecal coliforms in 102 (61.1%), and E. coli in 111 (66.5%). There were significant differences among the towns in the proportion of the samples contaminated with coliforms (P < 0.001) and E. coli (P < 0.001). Of 253 strains of E. coli studied, 4 (1.6%) were mucoid, 9 (3.6%) were hemolytic, and 37 (14.6%) were nonsorbitol fermenters. Of 69 isolates of E. coli tested, 10 (14.5%) were verocytotoxigenic. Twenty-eight (14.0%) of 200 E. coli isolates tested belonged to enteropathogenic serogroups. Standpipe, the most common water source, was utilized by 57 (34.1%) of the 167 households. Treated water (pipeborne in homes, standpipes, or truckborne) was supplied to 119 households (71.3%), while 48 households (28.7%) used water from untreated sources (rain, river/stream, or well) as their primary water supply. The type of household storage device was associated with coliform contamination. Water stored in drums, barrels, or buckets was more likely to harbor fecal coliforms (74.2% of samples) than was water stored in tanks (53.3% of samples), even after controlling for water source (P = 0.04). Compared with water from other sources, water piped into homes was significantly less likely to be contaminated with total coliforms (56.9% versus 88.8%, P < 0.001) and fecal coliforms (41.2% versus 69.8%, P < 0.01), even when the type of storage device was taken into account. However, fecal contamination was not associated with whether the water came from a treated or untreated source. We concluded that the drinking water in rural communities in Trinidad was grossly unfit for human consumption, due both to contamination of various water sources and during household water storage.     

Microbiological analysis of mineral water and drinking water of reservoir supplies,Brazil

The aim of this study was to evaluate the microbiological quality of different commercial mineral water brands, wells and reservoir supplies in surrounding areas of the city of Marília, Brazil, to determine the amount of total and fecal coliforms. Eighteen samples of each source (mineral and reservoir supplies) were analyzed using Colilert Technique in cellophane. The results revealed that one sample of mineral water and one sample collected from the reservoir supply had been contaminated by a bacterium of the total coliform group, and there were found one bacterium/100 ml of water. None of the water samples showed contamination by fecal coliforms.     

Microbial contamination of drinking water at the source and household storage level in the peri-urban area of southern Chennai and its implication on health, India

Aim

Microbial contamination of drinking water at the water source and household storage is the prime reason for the diarrheal prevalence in the developing counties. The goal of the study is to assess the microbial quality of household stored drinking water and its implication on health, particularly diarrhea.

Subjects and methods

To assess the microbial contamination of drinking water in Pallikaranai panchayat union located in southern Chennai, the samples were collected from seven source wells, at the point of distribution and from the household storage for 1–5 days. Total coliform and E. coli are analysed as it is the main indicator of microbial contamination. Most probable number and standard spread-plate method were used to enumerate the total coliform and E. coli bacteria respectively. Data on diarrheal disease were obtained from 290 children, and information on the source of water, household storage vessels and water treatment adopted by the household with recall period of 2 weeks was collected. The study was conducted in 2010 and 2012.

Results

The E. coli and total coliform were detected at the source level and the colony counts were increased gradually at the point of distribution and at the place of household storage. The analysis revealed that out of 26.2 % of respondents depending on the piped water supply, 22.3 % were affected with the diarrheal disease.

Conclusion

Household storage water is more contaminated than the piped water, indicating that interventions are needed to decrease the contamination of water at the place of household storage. The appropriate intervention for the low income category is chlorination and improving personal hygiene behaviour in regards to household water storage.     

Quality of Water the Slum Dwellers Use: The Case of a Kenyan Slum

As a result of rapid urbanization in a context of economic constraints, the majority of urban residents in sub-Saharan Africa live in slums often characterized by a lack of basic services such as water and sewerage. Consequently, the urban poor often use inexpensive pit latrines and at the same time may draw domestic water from nearby wells. Overcrowding in slums limits the adequate distance between wells and pit latrines so that micro-organisms migrate from latrines to water sources. Sanitary practices in these overcrowded slums are also poor, leading to contamination of these wells. This study sought to assess sanitary practices of residents of a Kenyan urban slum and fecal contamination of their domestic water sources. This cross-sectional study involved 192 respondents from Langas slum, Kenya. Forty water samples were collected from the water sources used by the respondents for laboratory analysis of coliforms. Of these 40 samples, 31 were from shallow wells, four from deep wells, and five from taps. Multiple-tube fermentation technique was used to enumerate coliform bacteria in water. The study found that most people (91%) in the Langas slum used wells as the main source of domestic water, whereas the rest used tap water. Whereas most people used pit latrines for excreta disposal, a substantial percentage (30%) of children excreted in the open field. The estimated distance between the pit latrines and the wells was generally short with about 40% of the pit latrines being less than 15 m from the wells. The main domestic water sources were found to be highly contaminated with fecal matter. Total coliforms were found in 100% of water samples from shallow wells, while 97% of these samples from shallow wells were positive for thermotolerant coliforms. Three out of the four samples from deep wells were positive for total coliforms, while two of the four samples were positive for thermotolerant coliforms. None of the samples from taps were positive for either total or thermotolerant coliforms. Because the presence of thermotolerant coliforms in water indicates fecal contamination, facilitated by the proximity between the wells and pit latrines, the study suggests that the pit latrines were a major source of contamination of the wells with fecal matter. However, contamination through surface runoff during rains is also plausible as indiscriminate excreta disposal particularly by children was also common. Owing to the fecal contamination, there is a high possibility of the presence of disease pathogens in the water; thus, the water from the wells in Langas may not be suitable for human consumption. To address this problem, treatment of the water at community or household level and intensive behavioral change in sanitary practices are recommended. Efforts should be made to provide regulated tap water to this community and to other slums in sub-Saharan Africa where tap water is not accessible. However, more sampling of different water sources is recommended.     

Molecular identification of coliform bacteria isolated from drinking water reservoirs with traditional methods and the Colilert-18 system

The accuracy of a traditional method (lactose utilization with acid and gas production) for the detection of coliform bacteria and E. coli was tested in comparison with method ISO 9308-1 (based on acid formation from lactose) and the Colilert-18 system (detection of beta-galactosidase). A total of 345 isolates were identified after isolation from water samples using API 20E strips. The Colilert-18 led to the highest number of positive findings (95% of the isolates were assigned to coliforms), whereas the ISO-9308-1 method resulted only in 29% coliform findings. With the traditional method only 15% were rated positive. Most of the isolates were identified by the API 20E system as Enterobacter spp. (species of the Enterobacter cloacae complex), Serratia spp., Citrobacter spp.and Klebsiella spp.; but species identification remained vague in several cases. A more detailed identification of 126 pure cultures by using 16S rRNA gene sequence analysis and analysis of the hsp60 gene resulted in the identification of Enterobacter nimipressuralis, E. amnigenus, E. asburiae, E. hormaechei, and Serratia fonticola as predominat coliforms. These species are beta-galactosidase positive, but show acid formation from lactose often after a prolonged incubation time. They are often not of fecal origin and may interfere with the ability to accurately detect coliforms of fecal origin.     

Prevalence of protozoa, viruses, coliphages and indicator bacteria in groundwater and river water in the Kathmandu Valley, Nepal

Limited information is available on the prevalence of waterborne pathogens in aquatic environments in developing countries. In this study, water samples were collected from nine shallow wells and a river in the Kathmandu Valley, Nepal, during the rainy season in 2009 and were subjected to detection of waterborne protozoa, viruses and coliphages using a recently developed method for simultaneous concentration of protozoa and viruses in water. Escherichia coli and total coliforms were also tested as indicator bacteria. At least one type of the five pathogens tested (Cryptosporidium, Giardia, human adenoviruses, and noroviruses of genogroups I and II) was detected in five groundwater samples (56%) (1000 ml each) from shallow wells. Compared with groundwater samples, the pathogens were more abundant in the river water sample (100 ml); the concentrations of Cryptosporidium and Giardia were 140 oocysts/l and 8500 cysts/l, respectively, and the mean threshold cycle (Ct) values in real-time RT-PCR were 34.3, 36.8 and 34.0 for human adenoviruses and noroviruses of genogroups I and II, respectively. Genotyping of F-RNA coliphages by real-time RT-PCR was successfully used to differentiate human and animal faecal contamination in the samples. Moreover, for the groundwater samples, protozoa and viruses were detected only in E. coli-positive samples, suggesting that E. coli may be an appropriate indicator of pathogen contamination of valley groundwater.     

Bacterial quality of drinking water stored in containers by boat households in Hue City, Vietnam

Objectives  To examine the bacterial quality of drinking water stored in containers by boat households in the river basin of Hue City, and associated factors. Methods  Ready-to-drink water stored in containers on boats was collected from 766 households. Escherichia coli (E. coli), total coliforms, and Enterobacteriaceae in the water were examined by the rehydratable dry-film plating method. Socioeconomic characteristics, water source, handling practices, and proficiency of disease prevention of individual households were assessed. Results   E. coli, over ten counts of total coliforms, and over ten counts of Enterobacteriaceae were detected in 25.7, 44.5, and 51.5% of 1-ml samples of ready-to-drink water stored in containers on the boats. Bacterial contamination of the water stored in containers by boat households was significantly associated with use of river water as a source of drinking water, non-boiling before storing containers for drinking, and limited proficiency in disease prevention regardless of the influence of socioeconomic characteristics of the households (P < 0.01, P < 0.05, P < 0.01, respectively). Conclusions  Bacterial contamination of ready-to-drink water stored by boat households was indicated. The households’ proficiency in disease prevention buffered contamination. A comprehensive health promotion program with a wide range of contents is required for the communities of boat households.     

Beobachtungen über parasitenbedingte Ausbrüche durch Trinkwasser und Maßnahmen zu deren Vermeidung Teil III: Seuchenhygienische Anforderungen

Our contemporary approach to securing drinking water free of disease-causing microorganisms derives essentially from the observation of and learning from earlier disease outbreaks. One of the best-known suggestions for controlling the quality of drinking water comes from Robert Koch. After the 1892 cholera outbreak in Hamburg, which afflicted 16,956 people of whom 8,605 eventually died, Robert Koch insisted that the surface water, which served as a source of drinking water, should be filtered. After filtration the colony count was supposed not to exceed 100/mL. The parasites Giardia and Cryptosporidia are transmitted by the fecal-oral route just like the classical epidemic microorganisms of cholera and typhoid fever. Hygienically safe water supply can be secured not by water analysis, but by appropriate measures aimed at elimination of possible parasites in water. The water-borne parasites differ from other bacterial and viral water contamination by their higher resistance to disinfection. The commonly used drinking water disinfectants are not effective with these parasites. The microorganisms thus have to be removed from the water naturally by the passage of the water in the underground or artificially by an appropriate filtration or flocculation filtration. The higher the fecal contamination of the source water, the more efficient the filtration process has to be. Water can be considered parasite-free only when no fecal material is detectable after the filtration before disinfection. The filtered water should not contain E. coli, coliform bacteria, fecal Streptococci and Clostridium perfringens. Such water should have the properties of a well-protected ground water. And even then the last step of the water treatment process should be disinfection, which further diminishes the residual risk of infection.     

Characterization of microbial populations associated with natural swimming pools

Natural swimming pools are artificially created bodies of water that are intended for human recreational bathing and have no chemical disinfection treatment. The microbial populations in four private natural swimming pools were analysed to assess the typical microbiological parameters, establish the origin of faecal contamination in the water, and predict the behaviour of larger systems that are open to the public. For this purpose, faecal coliforms, E. coli, enterococci, aerobic heterotrophic bacteria and Pseudomonas aeruginosa were enumerated in summer and winter. Moreover, faecal coliforms and enterococci populations were biochemically phenotyped with the Phene-Plate System, the diversity and similarity indexes were calculated and the isolates were identified. Three of the four natural pools exceeded the E. coli or enterococci limits stated in the recommendations for natural swimming pools. The concentrations of P. aeruginosa and aerobic heterotrophic bacteria were acceptable. The results suggest that wildlife was an important source of faecal pollution in the pools. Since there is a lack of regulations on these systems, and the health risks are higher than in conventional swimming pools, further research is needed to establish the parameters for ensuring safe bathing in private and public natural swimming pools.     

Modelling of enterobacterial loads to the Baie des Veys (Normandy,France)

The Baie des Veys (Normandy, France) has abundant stocks of shellfish (oyster and cockle farms). Water quality in the bay is affected by pollutant inputs from a 3500?km² watershed and notably occasional episodes of contamination by faecal coliforms. In order to characterise enterobacterial loads and develop a plan of action to improve the quality of seawater and shellfish in the bay, a two-stage modelling procedure was adopted. This focused on Escherichia coli and included a catchment model describing the E. coli releases, and the transport and die-off of this bacteria up to the coast. The output from this model then served as input for a marine model used to determine the concentration of E. coli in seawater.A total 60 scenarios were tested, including different wind, tidal, rainfall and temperature conditions and accidental pollution events, for both current situations and future scenarios. The modelling results highlighted the impact of rainfall on E. coli loadings to the sea, as well as the effects of sluice gates and tidal cycles, which dictated the use of an hourly timescale for the modelling process. The coupled models also made it possible to identify the origin of these enterobacteria as found in shellfish harvesting areas, both in terms of the contributing watercourses and the sources of contamination of those watercourses. The tool can accordingly be used to optimise remedial action.     

Contamination of weaning foods and transmission of enterotoxigenic Escherichia coli diarrhoea in children in rural Bangladesh

In longitudinal studies of infectious diseases and nutrition in Bangladesh, we determined the degree of bacterial contamination of traditional weaning foods and evaluated the role of these foods in the transmission of diarrhoeal diseases. 41% of samples of food items fed to weaning aged children contained Escherichia coli; these organisms were used as indicators of faecal contamination. Milk and foods prepared particularly for infants were more frequently and heavily contaminated with E. coli than was boiled rice, and E. coli levels were found to be related to the storage of cooked foods at high environmental temperatures. 50% of drinking water specimens also contained E. coli, but colony counts were approximately 10-fold lower than in food specimens. The proportion of a child's food samples that contained E. coli was significantly related to the child's annual incidence of diarrhoea associated with enterotoxigenic E. coli. This observation underscores the importance of seeking locally available foods that are hygienic as well as nutritious to supplement the diets of breastfeeding children in developing countries.     

Untersuchungen zum mikrobiologischen Status südbayerischer Badegewässer unter besonderer Berücksichtigung des Vorkommens thermophiler Campylobacter-Arten

Bacteriological analysis was performed in 2001 on 7.375 lake water samples and 2.211 river water samples from southern Bavaria according to Council Directive 76/160/EEC. The results showed that 90.7% of the lake water samples, but only 26.9% of the river water samples complied with the guide values; 0.7% of the lake water samples and 18.6% of the river water samples exceeded the mandatory limit values for fecal coliforms and/or total coliforms.In 211 samples from lakes and 170 samples from rivers the presence of thermophilic Campylobacter spp. was checked in 100 ml by cultural methods: 48 lake water samples and 76 river water samples proved positive.Although water samples with indicator concentrations exceeding the guideline values harbored significantly more frequently thermophilic Campylobacter spp., 19.8% of lake water samples and 28.1% of river water samples with indicator concentrations below the guideline values were contaminated with thermophilic Campylobacter spp.. Nearly 60% of the isolates were identified as Campylobacter jejuni, 25.8% as Campylobacter coli, and 6.5% as Campylobacter lari.     

MUG－EMB快速检定大肠杆菌的方法研究

通过对不同来源的５９１株大肠杆菌的测试，其β－葡萄糖醛酸酶阳性反应占菌株总数９４．８％。与部颁法比较，对１２０个样品进行大肠杆菌检测，两法均检出大肠杆菌的有１０个样品，未检出大肠杆菌的有１０９个样品，符合率为９９．１％；对２０５株阳性对照菌在样品中检测，两法同时检出大肠杆菌１９９株，未检出６株，符合率为９７．１％。改进的ＭＵＧ－ＥＭＢ法与部颁法的准确度、灵敏性完全一致。革兰氏阳性杆菌、球菌、芽胞菌属一些菌株亦有β－葡萄糖醛酸苷酶。     

Human and animal microbial source tracking in a tropical river with multiple land use activities

The enhancement and restoration of the water quality of deteriorating surface water resources can be challenging, particularly for rivers with multiple usages, such as agriculture, animal husbandry, human residence, and industries. Recently, the performance of DNA-based microbial source tracking (MST) indicators detected by end-point and quantitative PCR assays for identifying sources of fecal pollution from human sewage, swine, and cattle and non-host-specific (universal) fecal pollution in the Tha Chin River basin, Thailand, was evaluated. The present study monitored these validated MST markers and various physicochemical and microbial water quality parameters in samples collected from twelve stations along the Tha Chin River during four sampling events in the wet and dry seasons. No significant difference in precipitation was observed between the wet and dry samplings. Universal markers (both PCR and qPCR) were detected in all 48 samples, indicating persistent and continuing fecal contamination. The sewage- and swine-specific qPCR marker concentrations did not vary among the sampling events, whereas cattle-specific qPCR markers were detected only in the wet season. Animal-specific markers were detected in the lower Tha Chin River section, which is characterized by intensive animal farming. Sewage-specific markers were also found in the lower section and near an upstream residential area. The high agreement (87.5–100%) between the PCR and qPCR results suggested that PCR could serve as a lower-cost MST screening test that requires less technical expertise. A multivariate analysis conducted using the survival analysis procedure to include censored data also emphasized the high pollution in the lower section of the river at all sampling events. Universal and swine-specific markers showed moderate correlations with microbial indicators, including total coliforms, fecal coliforms, E. coli, and enterococci. None of the MST markers or microbial parameters were associated with the measured physicochemical parameters. This study provides the first evaluation of MST markers for monitoring surface freshwater in Thailand, and the findings might aid the pollution surveillance of impaired water bodies and the development of strategies for improving their water quality.     

Drinking Water Quality and the Geospatial Distribution of Notified Gastro-Intestinal Infections

Introduction

Even brief episodes of fecal contamination of drinking water can lead directly to illness in the consumers. In water-borne outbreaks, the connection between poor microbial water quality and disease can be quickly identified. The impact of non-compliant drinking water samples due to E. coli taken for regular monitoring on the incidence of notified acute gastrointestinal infections has not yet been studied.

Methods

The objective of this study was to analyse the geographical distribution of notified acute gastrointestinal infections (AGI) in Slovenia in 2010, with hotspot identification. The second aim of the study was to correlate the fecal contamination of water supply system on the settlement level with the distribution of notified AGI cases. Spatial analysis using geo-information technology and other methods were used.

Results

Hot spots with the highest proportion of notified AGI cases were mainly identified in areas with small supply zones. The risk for getting AGI was drinking water contaminated with E. coli from supply zones with 50–1000 users: RR was 1.25 and significantly greater than one (p-value less than 0.001).

Conclusion

This study showed the correlation between the frequency of notified AGI cases and non-compliant results in drinking water monitoring.     

河南省食饮单位生活饮用水水质调查分析

目的了解河南省食饮单位生活饮用水卫生现状,为监管部门提供有效的监管依据。方法抽检全省各地市、县的宾馆酒店、中小型饭店、学校及幼儿园餐厅的生活饮用水278份,依据GB/T5750-2006测定砷、铅、镉、汞4种重金属及菌落总数、总大肠菌群、耐热大肠菌群、大肠埃希氏菌等4项微生物指标,依据GB/5749-2006及重金属污染单因子指数法对数据进行评价。结果 2011年抽检136份,2013年抽检142份,总合格率分别为69.10%、67.60%,差异无统计学意义(x2=0.07,P>0.05);278份水样中,4种重金属全部合格,均为非污染程度;菌落总数、总大肠菌群、耐热大肠菌群、大肠埃希氏菌合格率分别为73.70%、76.60%、82.40%、92.10%;集中式供水、二次供水和分散式供水合格率分别为71.10%、88.70%和10.70%,差异有统计学意义(x2=53.79,P<0.01);宾馆酒店、中小型饭店、学校及幼儿园餐厅生活饮用水合格率分别为88.90%、57.80%、62.50%、65.40%,差异有统计学意义(x2=19.91,P<0.01)。结论河南省食饮单位生活饮用水的主要问题是微生物污染,而分散式供水方式水质的污染尤为严重。     

A prospective study of swimming-related illness. II. Morbidity and the microbiological quality of water

A prospective cohort epidemiological-microbiological study was carried out at 10 beaches in Ontario, Canada. Lake water and sediment samples collected at the beaches were analyzed for fecal coliforms, fecal streptococci, heterotrophic bacteria, Pseudomonas aeruginosa, and total staphylococci. Mean fecal coliform levels in the surface water of the lakes were within accepted guidelines. Bacterial densities were found to be approximately 10 times higher in the sediment than in the corresponding surface water samples. Morbidity among swimmers was shown to be related to staphylococcal counts, to fecal coliform levels, and, somewhat less strongly, to fecal streptococcal counts. Total staphylococci appeared to be more consistent indicators for predicting total morbidity rates among swimmers.     

Microbiological quality of drinking water of urban and rural communities,Brazil

OBJECTIVE: To evaluate the microbiological quality of treated and untreated water samples came from urban and rural communities and to examine the relationship between coliforms occurrence and average water temperature, and a comparison of the rainfall levels. METHODS: A sample of 3,073 untreated and treated (chlorinated) water from taps (1,594), reservoir used to store treated water (1,033), spring water (96) and private well (350) collected for routine testing between 1996 and 1999 was analyzed by the multiple dilution tube methods used to detect the most probable number of total and fecal coliforms. These samples were obtained in the region of Maring , state of Paran , Brazil. RESULTS: The highest numbers water samples contaminated by TC (83%) and FC (48%) were found in the untreated water. TC and FC in samples taken from reservoirs used to store treated water was higher than that from taps midway along distribution lines. Among the treated water samples examined, coliform bacteria were found in 171 of the 1,033 sampling reservoirs. CONCLUSIONS: Insufficient treatment or regrowth is suggested by the observation that more than 17% of these treated potable water contained coliform. TC and FC positive samples appear to be similar and seasonally influenced in treated water. Two different periods must be considered for the occurrence of both TC and FC positive samples: (i) a warm-weather period (September-March) with high percentage of contaminated samples; and (ii) cold-weather period (April-August) were they are lower. Both TC and TF positive samples declined with the decreased of water temperature.     

武汉市某酒店地下蓄水池污染的调查

目的了解武汉市某酒店饮用水的污染原因.方法2004年1月8日,武汉市某酒店饮用水受到污染,在发现污染的当时和处理过程中分别采集酒店内的二次供水(蓄水池水和水箱水)与市政供水,检测感官性状、一般化学和细菌学指标,按《生活饮用水水质卫生规范》(2001)进行评价.结果该酒店二次供水浑浊度增加,最高达3.82 NTU;并检出尿素、氨氮和氯化物,其浓度高于市政供水,游离余氯＜0.05 mg/L,细菌总数最高达940 cfu/ml,总大肠菌群最高＞1 600 MPN/100ml,并检出粪大肠菌群(130 MPM/100 ml).结论武汉市该酒店饮用水污染原因是地下蓄水池渗漏所致.