Microbiological Contamination Of Water Research Articles

Получение и применение иодированного бактерицида для дезинфекции воды в локальных системах очистки

The paper presents the results of studies on obtaining a bactericide based on iodized anion exchange resin АВ-17-8. The obtained compound bactericidal efficiency was assessed on Escherichia сoli culture suspensions at 103–109 CFU/mL. All experiments gave positive results and demonstrated the possibility of their use for natural water treatment in local water treatment systems. The obtained bactericidal filter can be used for quantitative determination of bacteriological contamination of the studied waters. Water samples contaminated with E. coli at 500, 1000, 5000 and 10000 CFU/mL were prepared to quantify the bactericidal activity of the iodine-containing compound obtained on an anion-exchange resin. Then samples were sequentially passed through a 100 cm3 bactericidal filter. By the amount of iodine released, the degree of microbial contamination can be determined. There were no microbial cells in the filtrate at zero concentrations of released iodine in the solution. The degree of microbiological contamination of water Q was 10,000 CFU/mL at 0.00391 g/L of iodine. A linear dependence between bactericidal activity and iodine release from the anion-exchange resin was established. This allows us to assume that the positive iodine radical is released “on a signal” – at the appearance of living microorganisms carrying excessive electrostatic charge. The released by the bactericide positive iodine radical (I*+) interacts only with the electrostatic charge of microorganisms, and not with the functional groups of their shells. The found quantitative dependence makes it possible to determine microbiological contamination based on the iodine concentration in the treated solution. Based on the test results, a flowchart of the technological process of surface water treatment was proposed. The presence of a bactericidal filter allows the use of a reverse osmosis filter, sensitive to biological water contaminants, as part of the installation.

Wilderness Medical Society Clinical Practice Guidelines on Water Treatment for Wilderness, International Travel, and Austere Situations: 2024 Update.

To provide guidance to medical providers, wilderness users, and travelers, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for treating water in situations where the potability of available water is not assured, including wilderness and international travel, areas impacted by disaster, and other areas without adequate sanitation. The guidelines present the available methods for reducing or eliminating microbiological contamination of water for individuals, groups, or households; evaluation of their effectiveness; and practical considerations. The evidence base includes both laboratory and clinical publications. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians.

The status of microbiological contamination of water using to produce bottled drinking water in Khanh Hoa province in 2022

Ninety-three samples of source water, used to produce bottled drinking water at bottled drinking water producers in Khanh Hoa province in 2022, were examined for microbiological criteria such as coliform, Escherichia coli, Pseudomonas aeruginosa, and HPC (Heterotrophic Plate Count). Results indicated that 19/93 (20.4%) of samples did not meet the microbiological requirements according to QCVN 01-1:2018/BYT. In which, the percentage of microbiological unsatisfactory well water (42.9%, 6/14) was higher than that of tap water (16.5%, 13/79). The proportion of source water samples of bottled drinking water facilities that did not meet the microbiological requirements in Cam Lam district (83.3%) was higher than those of Cam Ranh (33.3%), Dien Khanh (30%), Ninh Hoa (13.6%), Nha Trang (8%), and Van Ninh (7.7%). Unsatisfactory microbiological criteria included coliform (16.1%), P. aeruginosa (15.1%), and E. coli (1.1%). In addition, there were 8/93 (8.6%) samples with HPC higher than the recommended limit (500 CFU/mL) of the Environmental Protection Agency (EPA). The means of HPC, coliform, and P. aeruginosa were 4,2 × 102, 6,2 × 101, and 1,1 × 102 CFU/100 mL, respectively. Contaminated source water is one of the risks of microbiological contamination in finished bottled drinking water. Therefore, bottled drinking water producers in Khanh Hoa need to maintain good infection control and minimize the risk of microbial contamination from source water to finished bottled drinking water.  

Potential environmental and human health risks caused by heavy metals and pathogens from illegal landfill sites in Bosnia and Herzegovina

In Bosnia and Herzegovina, several illegal waste dumps pose a significant threat to soil and water contamination. The aim of this study was to determine the levels of heavy metal contamination of soils and microbiological contamination of water near investigated landfills. The goal was to identify the harmful effects of illegal landfills on the environment and public health, as well as assessing the potential of contaminants to pollute soil and water resources. Using an Atomic Absorption Spectrometer, the amounts and distribution of four heavy metals (Cd, Co, Pb, and Cr) in soil at four illegal landfills in Central Bosnia were studied. Three water samples collected near the dumpsites studied were tested for microbes. Bacteriological analyses of water included determination of total mesophilic aerobic bacteria, aerobic heterotrophic bacteria, total coliform and fecal coliform bacteria and fecal enterococci. Quantitative results were analyzed using an analysis of variance and Tukey HSD post hoc test. Concentrations of Cd (4.96 mg/kg) and Pb (206.97 mg/kg) recorded in soil at particular sites were above the limits of maximum allowable concentration. Cr and Pb values in soil samples were relatively higher on average than that of Cd and Co. Enrichment factor and pollution load index indicated high concentration of heavy metals in soil, especially Cd. Based on these results, waste from illegal landfills may release considerable amounts of harmful metals and microbes into the environment.

DESTRUCTION OF YEAST UNDER CONDITIONS OF SIMULTANEOUS ACTION OF CAVITATION AND ARGON

The aim of the study was to investigate the cavitation effect and inert gas on the viability of yeast in the water and to determine the gas effectiveness during cavitation treatment of the water system. Experimental data on the simultaneous action of argon bubbled at a rate of 0.2 cm3/s through an aqueous medium (volume 75 cm3) and ultrasonic cavitation (frequency 22 kHz, power 35 W) on the yeast Saccharomyces cerevisiae during the two-hour process are presented. The number of microorganisms per unit volume of test water was determined by the total number of colonies on the nutrient medium on Petri dishes. An active decrease in the number of cells at the beginning of the process (61.84% after 30 min) with the initial microbiological contamination of water 2.07 × 104 CFU/cm3 with the achievement of the proportion of dead cells > 98% after water treatment for 1 hour. The obtained results indicate intensive cavitation purification of water from the investigated microorganisms during argon bubbling.

(Digital Presentation) Biosensors – Researching at the Crossroads of Engineering and the Sciences

It has been a pleasure and honor to know Dr. Landheer for more than three decades and to have collaborated with him. In this invited presentation, I will focus on one aspect of our collaboration – the topic of Biosensors – which was our last research collaboration. In the list of references [1-15], I provide all publications we collaborated on since 1986.Biosensors are increasingly used in environmental applications, especially for water quality monitoring. This is because the availability of safe drinking water is fundamental to our good health. However, as water resources get increasingly stressed, ensuring a safe water supply and effective water treatment becomes increasingly important. In addition, waterborne illnesses are a significant public health problem. At the same time, current monitoring of microbiological contamination of water currently is time-consuming, laboratory based, and frequently compromises the timeliness of health advisory warnings even when contamination is found. Therefore, rapid detection of unsafe water can contribute greatly to mitigating the morbidity and mortality associated with waterborne diseases due to microbiological contaminants. Fortunately, the research community has shown increasing interest in the development of microtechnology-based sensors for the detection and identification of the bio-contaminants. These sensing systems use the same fabrication technology that has enabled the drastic lowering of cost, exponential increase in complexity of electronic chips and widespread availability of computing resources. In this presentation, we will discuss a low-cost, electrical, label-free microfabricated biosensor that we have been developing for pathogen detection related to water quality and also for ubiquitous-healthcare applications. The use of nano-dimensions devices to create futuristic nano-biosensors for both environmental and health applications will be introduced. And we will also describe our ongoing work to create highly integrated and parallel detection systems by integrating the sensor, the processing electronics and the pre-processing stages on the same cheap substrate. Finally, the success of such a low-cost, highly integrated sensing system demands a convergence of expertise from various engineering disciplines, the physical and life sciences as well as public health. References D Landheer et al, “Bioaffinity Sensors Based on MOS Field—Effect Transistors,” in Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications, Eds. Ren, Pearton, Taylor & Francis Books, Boca Raton, 215-265, 2010.MW Shinwari, et al, Microfabricated Reference Electrodes and their Biosensing Applications, Sensors, Vol. 10(3), pp. 1679-1715, 2010.MW Shinwari, MJ Deen, D Landheer, “Study of the Electrolyte-Insulator-Semiconductor Field-Effect Transistor with Applications in Biosensor Design,” Microelectronics Reliability, Vol. 47(12), pp. 2025-2057, 2007.D Landheer, et al, Calculation of the Response of Field-Effect Transistors to Charged Biological Molecules, IEEE Sensors Journal, Vol. 7, 1233-1242, 2007.WH Jiang, et al, Post-processing of Commercial CMOS Chips for the Fabrication of DNA Bio-FET Sensor Arrays, Proceedings of MRS Symposium - Fall Meeting, 6 pages, 2006.Bioelectronics, Biointerfaces, and Biomedical Applications 2, Eds., D Landheer, R. Bashir, M. Deen, C. Kranz, C. Liu, M. Madou, A. Offenhaeusser, R. Schasfoort, ECS Transactions, Vol. 3, Issue 26, 2006.MJ Deen, et al, Noise Considerations in Field-Effect Biosensors, Journal Applied Physics, Vol. 100, #074703, 8 pages, 2006.MJ Deen, et al, High Sensitivity Detection of Biological Species via the Field-Effect, Proceedings of the IEEE ICCDCS, Playa del Carmen, Mexico, pp. 381-385, 2006.D Landheer, et al, Model for the Field-Effect from Layers of Biological Macromolecules on the Gates of Metal-Oxide-Semiconductor Transistors, Journal Applied Physics, Vol. 98, # 044701, 2005.Silicon Nitride and Silicon Dioxide Thin Insulating Films, Eds., R.E. Sah, MJ Deen, D Landheer, K.B. Sundaram, W.D. Brown, D. Misra, ECS Proceedings PV-03, 636 pages 2003.Silicon Nitride and Silicon Dioxide Thin Insulating Films, Eds., K.B. Sundaram, MJ Deen, D Landheer, W.D. Brown, D. Misra, M.D. Allendorf, R.E. Sah, ECS Proceedings Volume PV 2001-7, 2001.MJ Deen, et al, Low Frequency Noise in Cadmium Selenide Thin-Film Transistors, Applied Physics Letters, Vol. 77(14), pp. 2234-2236, 2000.MJ Deen, et al, Low Frequency Noise in CdSe Thin-Film Transistors, ESSDERC 2000, Cork, Ireland, pp. 592-595, 2000.MJ Deen, et al, NbN Thin Films Reactively Sputtered with a High Field DC Magnetron, Journal of Vacuum Science and Technology A, Vol. 6(4), pp. 2299-2303, 1988.MJ Deen, et al, The Effect of the Deposition Rate on the Properties of DC Magnetron Sputtered NbN Thin Films, Bull Am Phys Soc., Vol. 32(3), p. 646, 1987.

Evaluation of surface water quality in recreational areas, an integrative proposal of chemical and microbiological markers

ResumenEl cambio climático afecta a las interacciones entre los sistemas hídricos, los ecosistemas y la atmósfera. También aumenta el riesgo de la presencia de microorganismos que afectan a los sistemas que utilizan estos recursos. El impacto de la población sobre los recursos hídricos se ha hecho más evidente en los últimos años, destacando la estrecha relación entre los niveles de componentes inorgánicos así como la contaminación microbiológica del agua y la salud de la comunidad. La caracterización de las variables que dan cuenta de la contaminación del agua es un proceso complejo. En este trabajo se propone la cuantificación de nitritos y fósforo como marcadores químicos y la detección de coliformes fecales, adenovirus humanos genómicos y/o picobirnavirus y enterovirus humanos infecciosos como marcadores microbiológicos para la prevención de infecciones de origen hídrico en individuos expuestos a matrices acuosas superficiales por actividades recreativas.

Integrated disease management: arboviral infections and waterborne diarrhoea

Water-related diseases such as diarrhoeal diseases from viral, bacterial and parasitic organisms and Aedes-borne arboviral diseases are major global health problems. We believe that these two disease groups share common risk factors, namely inadequate household water management, poor sanitation and solid waste management. Where water provision is inadequate, water storage is essential. Aedes mosquitoes commonly breed in household water storage containers, which can hold water contaminated with enteric disease-causing organisms. Microbiological contamination of water between source and point-of-use is a major cause of reduced drinking-water quality. Inadequate sanitation and solid waste management increase not only risk of water contamination, but also the availability of mosquito larval habitats. In this article we discuss integrated interventions that interrupt mosquito breeding while also providing sanitary environments and clean water. Specific interventions include improving storage container design, placement and maintenance and scaling up access to piped water. Vector control can be integrated into sanitation projects that target sewers and drains to avoid accumulation of stagnant water. Better management of garbage and solid waste can reduce the availability of mosquito habitats while improving human living conditions. Our proposed integration of disease interventions is consistent with strategies promoted in several global health frameworks, such as the sustainable development goals, the global vector control response, behavioural change, and water, sanitation and hygiene initiatives. Future research should address how interventions targeting water, sanitation, hygiene and community waste disposal also benefit Aedes-borne disease control. The projected effects of climate change mean that integrated management and control strategies will become increasingly important.

The Influence of Helium And Cavitation on the Yeast Life Process

Purpose of the study is to іnvestigate the simultaneous effect of cavitation and helium on the viability of yeast of the genus Saccharomyces cerevisiae in water. To study the change in the number of cells during cavitation treatment of the water system in the gas atmosphere. Methods. Yeast of Saccharomyces cerevisiae type were used as test microorganisms. Freshly prepared distilled desaerated water was used for the research, to which yeast cells were introduced with a microbiological loop. The volume of the model medium was cooled in a glass reactor with tap water, the temperature of which corresponded to 298 ± 1 K. The total duration of the process was 2 hours. The cavitation source was an ultrasonic generator UZDN-2T with frequency of 22 kHz and power of 35 W. The test water was bubbled with gas throughout the process. The test gas was helium. The number of microorganisms per unit volume of test water was determined by the total number of colonies on the nutrient medium on Petri dishes and expressed in colony-forming units (CFU). Results. In the experimental part of the work the process of water treatment with the content of yeast cells under cavitation conditions with simultaneous supply of helium is proposed. The efficiency of water purification from yeast as a result of the combined action of helium/cavitation has been established. The value of the effective rate constant of microorganisms destruction according to the kinetic reaction equation of the first order is calculated. The viability of yeast under cavitation conditions and bubbling of helium through the water system has been studied. The proportion of destroyed cells during the two-hour action of yeast-contaminated water at different treatment regimes was calculated and compared. An active decrease in the number of Saccharomyces cerevisiae in the aqueous medium at the beginning of the process with the achievement of the proportion of destroyed cells (Dd) 40.48% after 30 min of combined He/cavitation action at the initial microbiological water contamination of 4.2 · 103 CFU/cm3. NMend = 100 CFU/cm3 after 90 minutes of water treatment, that corresponds to the water purification degree > 97%. The end result is almost pure water, which allows to discharge treated water into natural water. Conclusions. The obtained results indicate intensive cavitation purification of water from the studied microorganisms in the experimental conditions. The influence of the studied gas nature on the process of destruction of microbiological contaminants in water is described.

Study of microbiological contamination level of surface water in MONITOX network areas before and after COVID-19 pandemic

The microbiological contamination of the water with faecal bacteria resulting from anthropogenic activity is an important issue for population health and the assessment of the presence of pathogenic bacteria in water is a major concern for the protection of humans and animals. Coliform bacteria are indicators for the assessment of faecal pollution and a potential presence of pathogens, which is caused mainly of untreated wastewater. In this paper, a comparative study was carried out in 32 sampling sites of MONITOX network in two periods, June 2019 and June-July 2020, before and after COVID-19 pandemic lockdown, regarding the rate of the water microbiological contamination in Lower Danube (Calarasi/Silistra-Galati-Tulcea sectors, Danube Delta and Black Sea coast, from SE part of Romania, by counting of the bacteria indicators of the organic pollution (heterotrophic bacteria and total coliforms). The results demonstrate a decrease of microbiological contamination of surface water in 2020 during the COVID-19 lockdown in all the samples collected form Black Sea coast, Danube branches, Danube-Black Sea confluence, and Danube river downwards Galati town.

Changing the Composition of Water Using an Universal Electro-Hydraulic Installation

Electro-hydraulic water treatment has a large number of factors. We considered two factors, nitrate increase and disinfection. Theoretically this process is described due to the fact that electro-hydraulic shock in water is accompanied by x-ray and ultraviolet radiation, all this causes a chemical process. The article proposes a method for increasing of nitrates in water and decontamination by electro-hydraulic impacts. (Research purpose) The research purpose is in searching for the optimal parameters and operating modes of a universal laboratory installation for the transformation of water into a nutrient solution. (Materials and methods) The EnSURE (Hygiena) luminometer was used to measure microbiological contamination of water, and the ETHAN PH meter/ionometer was used to measure nitrates in water. (Results and discussion) The article presents the existing electrohydraulic devices and showes their shortcomings. Author made the conclusion that there is no universal installation in which it would be possible to get a double effect (activation and disinfection). The article presents a developed universal laboratory unit, which was used to perform disinfection and increase nitrates. The article presents the operation modes in which the effect is observed. The article presents the photo of the laboratory installation. (Conclusions) It was found that for economic reasons it is advisable to choose the first mode for water treatment. Author have identified an organic method for increasing nitrates in water and decontamination, which can be used in greenhouse complexes for growing vegetables and fruits. Pond water was treated for conversion to a nutrient solution by changing the amount of nitrates. It was found that the amount of nitrates increased by 0.86 milligrams per liter, which indicates that the water passed into a nutrient solution.

Study of the microbiological quality, prevalence of foodborne pathogens and product shelf-life of Gilthead sea bream (Sparus aurata) and Sea bass (Dicentrarchus labrax) from aquaculture in estuarine ecosystems of Andalusia (Spain)

This study was aimed at characterizing microbiologically Gilthead sea bream (Sparus aurata) and Sea bass (Dicentrarchus labrax) produced in two estuarine ecosystems in Andalusia (Spain): the estuary of the river Guadalquivir (La Puebla del Río, Sevilla) (A), and the estuary of the river Guadiana (Ayamonte, Huelva) (B). The collected fish individuals and water were analysed for hygiene indicator microorganisms and pathogens. The statistical analysis of results revealed that microbial counts for the different microbiological parameters were not statistically different for fish type. On the contrary, considering anatomic part, viscera showed significantly higher concentrations for Enterobacteriaceae, total coliforms and for Staphylococcus spp. coagulase +. Furthermore, location A showed in water and fish higher levels for lactic acid bacteria, aerobic mesophilic bacteria, Enterobacteriaceae, total coliforms and Staphylococcus spp. coagulase +. Neither Listeria monocytogenes, nor Salmonella spp. were detected, though Vibrio parahaemolyticus was identified, molecularly, in estuarine water in location B. The predictive analysis demonstrated that the initial microbiological quality could have an impact on product shelf-life, being longer for location B, with better microbiological quality. Results stress the relevance of preventing the microbiological contamination of water in estuary production systems in order to assure the quality and safety of Gilthead sea bream and Sea bass.

Silver-Modified Mexican Clinoptilolite-Rich Tuffs With Various Particle Sizes as Antimicrobial Agents Against Escherichia coli

Water disinfection was performed using Mexican clinoptilolite-rich tuffs from Oaxaca and Sonora with different particle sizes exchanged with silver ions. Samples of Escherichia coli (ATCC 8739) suspended in distilled water (wastewater-like) and municipal wastewater containing coliforms (E. coli as a representative microorganisms from the coliform consortium), were treated in this investigation. E. coli is considered an indicator of microbiological contamination of water, so levels of this microorganism after zeolite treatment indicate how well the disinfection process worked. It was found that particle size, the amount of silver in the modified zeolitic rocks, the origin of the zeolitic material and the type of aqueous media containing E. coli all play important roles in the wastewater disinfection process.

Survival and Antibiotic Resistance of Bacteria in Artificial Snow Produced from Contaminated Water.

This study shows microbiological contamination of water in two main Podhale rivers, whose resources are used for the production of artificial snow, and the resulting snow contamination. Thirty-one E. coli strains were isolated from snow at two ski stations in the studied region, their antimicrobial resistance was determined, and the presence of extended spectrum β-lactamase (ESBL) genes was searched for. The results indicate that the waters of both rivers are severely contaminated, resulting in the contamination of artificial snow with, among others, thermotolerant E. coli. E. coli isolated from snow were most frequently resistant to ampicillin (74.19%) and amoxicillin/clavulanate (51.61% isolates). Aminoglycosides and third generation cephalosporins were most efficient among the tested antimicrobials. Some bacterial strains were multidrug resistant and three strains exhibited the ESBL mechanism. Molecular analyses showed the presence of ESBL genes in the same three strains. Genetic variation among E. coli indicates that only some genotypes are able to survive the artificial snow production process.

FRNA Bacteriophages as Viral Indicators of Faecal Contamination in Mexican Tropical Aquatic Systems

A particular challenge to water safety in populous intertropical regions is the lack of reliable faecal indicators to detect microbiological contamination of water, while the numerical relationships of specific viral indicators remain largely unexplored. The aim of this study was to investigate the numerical relationships of FRNA-bacteriophage genotypes, adenovirus 41, and human adenoviruses (HADV) in Mexican surface water systems to assess sewage contamination. We studied the presence of HADV, HADV41 and FRNA bacteriophage genotypes in water samples and quantified by qPCR and RT-qPCR. Virus and water quality indicator variances, as analyzed by principal component analysis and partial least squared regression, followed along the major percentiles of water faecal enterococci. FRNA bacteriophages adequately deciphered viral and point source water contamination. The strongest correlation for HADV was with FRNA bacteriophage type II, in water samples higher than the 50th percentiles of faecal enterococci, thus indicating urban pollution. FRNA bacteriophage genotypes I and III virus indicator performances were assisted by their associations with electrical conductivity and faecal enterococci. In combination, our methods are useful for inferring water quality degradation caused by sewage contamination. The methods used have potential for determining source contamination in water and, specifically, the presence of enteric viruses where clean and contaminated water have mixed.

English

Some Salmonella spp. are important pathogenic bacteria that can be transmitted to people via food and water and that can cause disease characterized by mild to severe enteric and systemic illness. In developing countries, infections caused by pathogenic antibiotic resistant Salmonella spp. are a major health challenge, particularly in children. Through the use of membrane filtration and Environmental Protection Agency (EPA) 1200 methods, the presence of fecal coliforms and antibiotic resistant Salmonella spp. in surface water sources was investigated, some of which had shared access for animals and people. Out of 100 water samples, 76 were positive for fecal coliforms and 63% of the positive samples contained >100 CFU / 100 ml of water. We observed a significant positive correlation between the number of fecal coliforms and the presence of Salmonella spp. (r=0.46, n=100, P=0.01). Importantly, >26% of the samples were positive for Salmonella spp. and 88% of these samples harbored isolates resistant to ≥1 antibiotic. Moreover, we found that 26% of antibiotic resistant Salmonella spp. isolates were able to transfer their resistance traits to a recipient strain of Escherichia coli at the rate of 1-7 x 10-3 per donor cells. Microbiological contamination of water was clearly evident in open water sources from northern Tanzania, and the presence of Salmonella spp. poses an immediate risk to anyone who consumes these waters if untreated. Key words: Fecal bacteria, Salmonella, invA gene, polymerase chain reaction (PCR), water.

EVALUTION OF THE CHEMICAL AND MICROBIOLOGICAL CONTAMINATION OF THE RIVER SITNICA WATERS (KOSOVO): A STATISTICAL APPROACH

Abstract: Chemical and microbiological contamination of ground water has several implications for human health. The study of chemical and microbiological contamination of water was carried out in Sitnica river (Kosova). Water samples were collected in 10 sampling points and fourteen different parameters are investigated. The program “Statistica ver. 6.0” has been used for calculations of basic statistical parameters and anomalies (extremes and outliers). These chemometric approaches and results yielded useful information about water quality and can lead to better water resource management. Dendograms and box-whisker plots were drawn to evaluate the chemical variation. The levels of some microbiological and phisico-chemical parameters and ecotoxic ions from surface waters are compared with the results from the river source where anthropogenic effects are negative. Our results show for chemical and microbiological pollutions as results of anthropogenic factors coming from settlements, peripheral rivers and agricultural in the region surround.

Dental Unit Water Line Management

Practices need to prevent and treat microbiological contamination of water in dental unit water line systems to minimise the risk of infection

Circuit Rider post-construction support: improvements in domestic water quality and system sustainability in El Salvador.

Small piped water supply systems are often unable to provide reliable, microbiologically safe, and sustainable service over time, and this has direct impacts on public health. Circuit Rider (CR) post-construction support (PCS) addresses this through the provision of technical, financial, and operational assistance to these systems. CRPCS operates in low and high-income countries; yet, no rigorous studies of CRPCS exist. We measured the impact of CRPCS on 'water quality' and 'sustainability' indicators (technical and administrative capacity, and water supply protection) in El Salvador. In this field-based study, a case-control design was utilized in 60 randomly selected case (28 CR) and comparable control (32 noCR) communities. Microbiological water quality tests and pre-tested structured key-informant interviews were conducted. The operational costs of CRPCS were also assessed. Data were compared using parametric and non-parametric statistical methods. We found communities with CRPCS had significantly lower microbiological water contamination, better disinfection rates, higher water fee payment rates, greater transparency (measured by auditable banking records), greater rates of household metering, and higher spending for repairs and water treatment than comparable control communities. CRPCS is also a low-cost (<$1 per household/year in El Salvador) drinking water intervention.

Microbiological contamination in water filtration plants in Islamabad.

To determine the frequency of microbiological contamination of water in different water filtration plants in Islamabad. Descriptive cross-sectional study. Water Filtration Plants (WFP) in different sectors of Islamabad, from April to September 2012. Water samples were collected in sterilized bottles according to the standard water sampling protocol from site and transported to Pakistan Council for Research in Water Resources (PCRWR) for analysis. Microbiological quality of water was determined in terms of total coliforms (< 2.0 MPN/100 ml) and Escherichia coli (< 2.0 MPN/100 ml). Microbiological contaminated water was defined the sample which had more than 2.0 MPN per 100 ml of either total coliforms or Escherichia (E.) coli. Thirty two WFP were analyzed for microbiological contamination. E. coli was present in 8 (25.0%) water samples, while 24 (75.0%) water samples were free from it. Total coliforms were present in 13 (40.6%) of the samples of WFP, while 19 (59.3%) samples were free from total coliform. Faecal coliforms were present in 8 (25.0%) and absent in 24 (75.0%) samples. Both E. coli and total coliform were present in 8 (25.0%) samples. Nine (59.3) WFP were free from E. coli, total coliform and faecal coliform. Statistically, no significant association was found (p > 0.05) between microbiological contamination and the sectors. Less than half of the water samples of the WFP were contaminated while certain sectors showed more frequent contamination than others.