Na odontologia, o biofilme formado nas linhas d\'água de equipos odontológicos pode disseminar a contaminação microbiana na água. O objetivo desta pesquisa foi investigar a contaminação microbiana da água de abastecimento e de equipos odontológicos antes e após a implementação de um protocolo para melhoria e manutenção da qualidade microbiológica da água de equipos odontológicos, bem como desenvolver produtos antibiofilme com possível aplicabilidade nas linhas d\'água. A carga microbiana da água de 27 torneiras e equipos (reservatórios, seringas tríplice e alta rotação) de uma clínica odontológica foi avaliada por meio do sistema Petrifilm(TM) (bactérias aeróbias totais e fungos) e meios de cultura convencionais (enterobactérias e Legionella spp.) em duas etapas distintas, sendo a segunda análise realizada após a implementação de um protocolo para melhoria e manutenção da qualidade microbiológica da água dos equipos. Ainda, as atividades antibacteriana (concentração inibitória mínima - hipoclorito de sódio, ácido cítrico, bicarbonato de sódio, cloreto de sódio, dodecil sulfato de sódio, peróxido de hidrogênio, polissorbato 20 e quitosana) e antibiofilme (biomassa total e viabilidade celular) foram determinadas in vitro a partir de substâncias e produtos com possível aplicabilidade na desinfecção de linhas d\'água de equipos. As amostras de água das torneiras apresentaram carga bacteriana dentro do parâmetro estabelecido pela legislação brasileira, no entanto, as seringas tríplices e os alta rotação não. A implementação do protocolo para manutenção da qualidade microbiológica da água dos equipos demonstrou uma redução nas cargas bacteriana e fúngica apenas nos alta rotação. Enterobactérias e Legionella spp. não foram isoladas das amostras de água das torneiras e dos equipos. De acordo com a concentração inibitória mínima, o ácido cítrico, bicarbonato de sódio, cloreto de sódio, hipoclorito de sódio e peróxido de hidrogênio demonstraram as melhores atividades antibacterianas. As melhores atividades antibiofilme (biomassa total) foram do peróxido de hidrogênio a 5% (E. coli e P. aeruginosa), ácido cítrico a 30% (P. aeruginosa) e bicarbonato de sódio a 30% (S. aureus). Os produtos (Wanitox A e Wanitox B) desenvolvidos apresentaram atividade antibiofilme (viabilidade celular) contra a E. coli e S. aureus. Assim, os produtos desenvolvidos nesta pesquisa apresentaram possível aplicabilidade no enfrentamento do biofilme nas linhas d\'água de equipos odontológicos, que permanece como um dos grandes desafios na odontologia. Ainda, pesquisas adicionais são necessárias para o aperfeiçoamento e aplicabilidade destes produtos. / In dentistry, biofilm formed on dental unit waterlines can disseminate microbial contamination in water. The objective of this research was to determine the microbial contamination of water from supplies and dental units before and after the implementation of a protocol for improvement and maintenance of microbiological water quality of water from dental units as well as to develop antibiofilm products with possible applicability in waterlines. The microbial load of water from 27 taps and dental units (reservoirs, air-water syringes and high-speed turbines) in a dental clinic was evaluated through a Petrifilm(TM) system (total aerobic bacteria and fungi) and conventional culture mediums (enterobacteria and Legionella spp.) in two distinct stages, being the second analysis performed after the implementation of a protocol for improvement and maintenance of microbiological water quality of water from dental units. Moreover, the antibacterial (minimum inhibitory concentration - sodium hypochlorite, citric acid, sodium bicarbonate, sodium chloride, sodium dodecyl sulfate, hydrogen peroxide, polysorbate 20 and chitosan) and antibiofilm (total biomass and cell viability) activities were determined in vitro from substances and products with possible applicability in disinfection of dental unit waterlines. The water samples from taps presented bacterial load within the parameter established by Brazilian legislation; however, air-water syringes and high-speed turbines did not. The protocol implementation for maintenance of microbiological water quality of water from dental units showed a decrease on bacterial and fungal loads only on high-speed turbines. Enterobacteria and Legionella spp. were not isolated from water samples from taps and dental units. According to minimum inhibitory concentration, citric acid, sodium bicarbonate, sodium chloride, sodium hypochlorite and hydrogen peroxide showed the best antibacterial activities. The best antibiofilm activities (total biomass) were from 5% hydrogen peroxide (E. coli and P. aeruginosa), 30% citric acid (P. aeruginosa) and 30% sodium bicarbonate (S. aureus). The developed products (Wanitox A and Wanitox B) showed antibiofilm activity (cell viability) against E. coli and S. aureus. Thus, the products developed in this research presented a possible applicability in confrontation with biofilm on dental unit waterlines, and this remains as a major challenge in dentistry. Besides, additional researches are necessary for enhancement and applicability of these products.

Historical water quality databases from two South Australian drinking water reservoirs were used, in conjunction with various computational modelling methods for the ordination, clustering and forecasting of complex ecological data. Techniques used throughout the study were: Kohonen artificial neural networks (KANN) for data categorisation and the discovery of patterns and relationships, recurrent supervised artificial neural networks (RANN) for knowledge discovery and forecasting of algal dynamics and hybrid evolutionary algorithms (HEA) for rule-set discovery and optimisation for forecasting algal dynamics. These methods were combined to provide an integrated approach to the analysis of algal populations including interactions within the algal community and with other water quality factors, which results in improved understanding and forecasting of algal dynamics. The project initially focussed on KANN for the patternising and classification of the historical data to reveal links between the physical, chemical and biological components of the reservoirs. This offered some understanding of the system and relationships being considered for the construction of the forecasting models. Specific investigations were performed to examine past conditions and the impacts of different management regimes, as well as to discover sets of conditions that correspond with specific algal functional groups. RANN was then used to build models for forecasting both Chl-a and the main nuisance species, Anabaena, up to 7 days in advance. This method also provided sensitivity analyses to demonstrate the relationship between input and output variables by plotting the reaction of the output to variations in the inputs. Initially one year from the data set was selected for the testing of a model, as per the split-sample technique. To further test the models, it was later decided to select several years for testing to ensure the models were useful under changed conditions, and that test results were not misleading regarding the models true capabilities. RANN were firstly used to create reservoir specific or ad-hoc models. Later, the models were trained with the merged data sets of both reservoirs to create one model that could be applied to either reservoir. Another method of forecasting was trialled and compared to RANN. HEA was found to be equal or superior to RANN in predictive power, also allowed sensitivity analysis and provided an explicit, portable rule set. The HEA rule sets were initially tested on selected years of data, however to fully demonstrate the models potential, a process for k-fold cross-validation was developed to test the rule-set on all years of data. To further extend the applicability of the HEA rule-set; the idea of rule-based agents for specific lake ecosystem categories was examined. The generality of a rule-based agent means that, after successful validation on several lakes from one category, the agent could then be applied to other water bodies from within that category that had not been involved in the training process. The ultimate test of the rule-based agent for the warm monomictic and eutrophic lake ecosystem category was to be applied to a real-time monitoring and forecasting situation. The agent was fed with online, real-time data from a reservoir that belonged to the same ecosystem category but was not used in the training process. These preliminary experiments showed promising results. It can be concluded that the concept of rulebased agents will facilitate real-time forecasting of algal blooms in drinking water reservoirs provided on-line monitoring of relevant variables has been implemented. Contributions of this research include: (1) to offer insight into the capabilities of 3 kinds of computational modelling techniques applied to complex water quality data, (2) novel applications of KANN including the division of data into separate management periods for comparison of management efficiency, (3) to both qualitatively and quantitatively elucidate relationships between water quality parameters, (4) research toward the development of a forecasting tool for algal abundance 7 days in advance that could be generic for a particular lake ecosystem category and implemented in real-time, and (5) to suggest a thorough testing method for such models (k-fold cross validation). / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1331584 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

Gram-negative infection has been linked to hospital water although few studies have examined whether water systems are reservoirs of nosocomial pathogens. This study investigated longitudinal recovery of the opportunistic pathogens Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumannii from water outlets of a haematology unit and evaluated Point-Of-Use Filtration (POU-F) as a control measure. In a two-year double cross-over trial, water samples and swabs were taken weekly from 39 showers/taps on the unit. Four study phases alternated between non-filtered (Phases 1 & 3), and filtered outlets (Phases 2 & 4) using Pall AquasafeTM 14-day filters. In Phases 1 & 3; 99% of 1396 samples yielded bacterial growth, with colonies generally too numerous to count. Target species were isolated from 22% of water samples (P. aeruginosa 14%; S. maltophilia 10%) and 10% of swabs. P. aeruginosa was particularly associated with handwash stations and S. maltophilia with showers. A. baumannii was not isolated. With POU-F; 22% of 1242 samples yielded bacterial growth (mean CFU/100ml ,4.6). S. maltophilia was isolated only once from water but never from outlet swabs. PCR typing identified clusters of isolates colonizing different outlets over time but no clear association between water and patient isolates was identified. The incidence of Gram negative infections remained low throughout the study. Without POU-F, water from taps/showers represented a source of bacteria including the target species. POU-F substantially reduced the frequency and number of target species from every outlet, and merits further investigation as an intervention to protect immunocompromised patients from opportunistic pathogens.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Enfermagem, Escola de Enfermagem, 2006. / Submitted by eloisa silva (eloisa1_silva@yahoo.com.br) on 2012-11-14T16:35:36Z No. of bitstreams: 1 cesarcosta.pdf: 536772 bytes, checksum: 522e343b4b7980c91481ee260545e9d0 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-11-14T22:14:01Z (GMT) No. of bitstreams: 1 cesarcosta.pdf: 536772 bytes, checksum: 522e343b4b7980c91481ee260545e9d0 (MD5) / Made available in DSpace on 2012-11-14T22:14:01Z (GMT). No. of bitstreams: 1 cesarcosta.pdf: 536772 bytes, checksum: 522e343b4b7980c91481ee260545e9d0 (MD5) Previous issue date: 2006 / Este estudo teve, por objetivo, identificar a presença dos microrganismos patogênicos do grupo coliforme, e de outros microrganismos e parasitos humanos potencialmente patogênicos existentes nas águas que margeiam a cidade do Rio Grande/RS, bem como elaboração de uma proposta de intervenção na esfera da vigilância em saúde ambiental. Foi realizado um estudo descritivo, onde foram coletadas amostras de água em 12 pontos pré determinados, nos meses de outubro de 2004 e janeiro, abril, julho e outubro de 2005. Em cada amostra coletada procedeu-se à identificação de enterobactérias e parasitos potencialmente patogênicos de interesse humano. Na análise estatística, procedeu-se ao cálculo de freqüências absolutas e relativas dos dados obtidos. Realizou-se também o levantamento do funcionamento dos sistemas de informações em saúde ao nível local e regional para determinados agravos e, a partir dos dados encontrados, esboçaram-se algumas ações em saúde. Das 48 amostras estudadas, em 100% foi identificada a presença das bactérias Escherichia coli, Proteus, Salmonella e uma enterobactéria não identificada. Cabe salientar que Escherichia coli foi identificada em número superior a 1.000/100 ml de água; as amostras positivas para parasitos foram 17 (35,4%); oocistos de Cryptosporidium spp. encontrados em 2 amostras(4,2%); a ameba de vida livre, gênero Acanthamoeba, em 12 amostras (25%); e a ameba de vida livre, gênero Naegleria, em 3 amostras (6,3%). Nos pontos de coleta observou-se forte presença de atividade humana ou eliminação de dejetos. A análise dos sistemas de informações em saúde revelou a falta de vigilância ambiental dirigida ao objeto de estudo. Diversas ações com vistas a contribuir com o manejo da situação e a reduzir o possível agravo foram propostas, tais como: monitoramento dos pontos de coleta; instalação de sistema sentinela; ações educativas integradas; implementação da pesquisa; participação multidisciplinar e interinstitucional. Concluiu-se que a água do entorno da cidade estudada apresenta níveis significativos de enterobactérias e de parasitos potencialmente danosos para a população, tornando necessária a implementação de políticas e medidas para controlar esta situação. / This study had the purpose to identify the presence of pathogenic microorganisms from the group Coliforme, and other microorganisms and human potentially pathogenic parasites existing in the boarding waters of the city of Rio Grande-RS and to elaborate a proposal of intervention in the Vigilance of the environment health’s sphere. A descriptive study has been done where the water is collected in 12 predeterminated spots during the months of October/2004 and January, April, July and October/2005. In each collected sample an identification of enterobactéria and potentially pathogenic parasites of human interest was proceeded. In the statistic analysis, a calculation of the absolute and relative frequencies from the obtained data was made. Also a research of the work of the health local and regional information for determinated damage and some actions in heath were sketched from the obtained data. Forty eight samples were studied, 100% presented the presence of Escherichia coli, Proteus, Salmonella bacterium and non-identified enterobactéria, it’s good to set off that Escherichia coli was identified in number superior than 1000/100ml of water. The positive samples were 17(35,4%) for parasites. Oocistos of Cryptosporidium spp were found in 2 samples (4,2%), the free life Ameba, genus Acanthamoeba in 12 samples(25%) and the free life Ameba, genus Naegleria in 3 samples (6,3%). In the collecting spots was found strong presence of human activity and/or elimination of garbage. The analyses of the health information system revealed the lack of environment vigilance directed to the object of study. Several actions in order to contribute with the manage of the situation and reduce the possible damage were proposed, such as: watch the collect spots;installation of a sentinel system; integrated educative actions; encourage the research; multidiscipline participation. The conclusion is that the boarding water of the studied city presents significant level of enterobactéria and parasites potentially damaging for the population, tuning to necessary the implantation of measures to control this situation. / Este estudio tuvo, por objetivo, Identificar la presencia de los microrganismos patógenos del grupo coliforme, y de otros microrganismos y parasitos humanos potencialmente patógenos existentes en las aguas que marginan la ciudad de Rio Grande – Rs, bien como elaboración de una propuesta de intervención en la esfera de la vigilancia en salud ambiental. Fue hecho un estudio descriptivo, donde se realizaron colectas de agua en 12 puntos pre-determinados, en los meses de octubre de 2004 y enero, abril,juli y octubre de 2005. En cada muestra colectada se procedió a la identificación de enterobactérias y parasitos potencialmente patógenos de interés humano. En el análisis estadístico, se procedió al cálculo de frecuencias absolutas y relativas de los datos logrados. se realizó también el levantamiento del funcionamiento de los sistemas de informaciones en salud a nivel local y regional para determinadas situaciones y, a partir de los datos encontrados, se esbozaron algunas acciones en salud. De las 48 muestras estudiadas, en un 100% fue identificada la presencia de las bacterias Escherichia coli, Proteus, Salmonella y una enterobactéria no identificada. Cabe destacar que Escherichia coli fue identificada en número superior a 1.000/100 ml de agua; las muestras positivas para parasitos fueron 17 (35,4%); oocistos de Cryptosporidium spp fueron encontrados en 2 muestras (4,2%); la Amiba de vida libre, género Acanthamoeba, en 12 muestras (25%); y la Amiba de vida libre, género Naegleria, en 3 muestras (6,3%). En los puntos de colecta se observó fuerte presencia de actividad humana o eliminación de dejetos. El análisis de los sistemas de informaciones en salud reveló la falta de vigilancia ambiental dirigida al objeto de estudio. Diversa acciones con vistas a contribuir con el manejo de la situación y a reducir los posibles daños fueron propuestas, tales como: monitorización de los puntos de colecta; instalación de sistema centinela; acciones educativas integradas; implementación de la pesquisa; participación multidisciplinaria e interinstitucional. se concluyó que el agua del entorno de la ciudad estudiada presenta niveles significativos de enterobactérias y de parasitos potencialmente dañosos para la población, tornando necesaria la implementación de políticas y medidas para controlar esta situación.

Water, sanitation and hygiene-related diseases are responsible for 7% of all deaths and 8% of all disability adjusted live years (DALYs), as well as the loss of 320 million days of productivity in developing countries. Though laboratory and field trials have shown that household water treatment (HWT) technologies can quickly improve the microbiological quality of drinking water, questions remain about the effectiveness of these technologies under real-world conditions. Furthermore, the value that rural communities attach to HWT is unknown, and it is not clear why, in spite of the fact that rural African households need household water treatment (HWT) most, they are the least likely to use them. The primary objective of this multi-level study was to assess the post-implementation effectiveness of selected HWT technologies in the Nyanza and Western Provinces of Kenya. The study was carried out in the rainy season between March and May, 2011 using a mixed method approach. Evidence was collected in order to build a case of evidence of HWT effectiveness or ineffectiveness in a post-implementation context. A quasi-experimental design was used first to conduct a Knowledge, Attitudes and Practices (KAP) survey in 474 households in ten intervention and five control villages (Chapter 3). The survey assessed the context in which household water treatment was being used in the study villages to provide real-world information for assessing the effectiveness of the technologies. An interviewer-administered questionnaire elicited information about the water, sanitation and hygiene-related KAP of the study communities. A household water treatment (HWT) survey (Chapter 4) was carried out in the same study households and villages as the KAP study, using a semi-structured questionnaire to gather HWT adoption, compliance and sustained use-related information to provide insight into the perceived value the study households attach to HWT technologies, and their likelihood of adoption of and compliance with these technologies. The drinking water quality of 171 (one quarter of those surveyed during KAP) randomly selected households was determined and tracked from source to the point of use (Chapter 5). This provided insights into HWT effectiveness by highlighting the need for HWT (as indicated by source water quality) and the effect of the study households’ KAP on drinking water quality (as indicated by the stored water quality). Physico-chemical and microbiological water quality of the nineteen improved and unimproved sources used by the study households was determined, according to the World Health Organisation guidelines. The microbiological quality of 291 water samples in six intervention and five control villages was determined from source to the point-of-use (POU) using the WHO and Sphere Drinking Water Quality Guidelines. An observational study design was then used to assess the post-implementation effectiveness of the technologies used in 37 households in five intervention villages (Chapter 6). Three assessments were carried out to determine the changes in the microbiological quality of 107 drinking water samples before treatment (from collection container) and after treatment (from storage container) by the households. The criteria used to assess the performance of the technologies were microbial efficacy, robustness and performance in relation to sector standards. A Quantitative Microbial Risk Assessment (QMRA) was then carried out in the HWT effectiveness study households to assess the technologies’ ability to reduce the users’ exposure to and probability of infection with water-borne pathogens (Chapter 7). The KAP survey showed that the intervention and control communities did not differ significantly in 18 out of 20 socio-economic variables that could potentially be influenced by the structured manner of introducing HWT into the intervention villages. The majority of the intervention group (IG) and the control group (CG) were poor or very poor on the basis of household assets they owned. The predominant level of education for almost two-thirds of the IG and CG respondents was primary school (completed and non-completed). Though very few were unemployed in IG (8.07%) and CG (14.29%), the two groups of respondents were predominantly engaged in subsistence farming — a low income occupation. With regard to practices, both groups had inadequate access to water and sanitation with only one in two of the households in both IG and CG using improved water sources as their main drinking water source in the non-rainy season. One in ten households in both study groups possessed an improved sanitation facility, though the CG was significantly more likely to practice open defecation than the IG. The self-reported use of soap in both study groups was mainly for bathing and not for handwashing after faecal contact with adult or child faeces. Despite the study groups' knowledge about diarrhoea, both groups showed a disconnection between their knowledge about routes of contamination and barriers to contamination. The most frequent reason for not treating water was the perceived safety of rain water in both the IG and CG. / The HWT adoption survey revealed poor storage and water-handling practices in both IG and CG, and that very few respondents knew how to use the HWT technologies correctly: The IG and CG were similar in perceived value attached to household water treatment. All HWT technologies had a lower likelihood of adoption compared to the likelihood of compliance indicators in both IG and CG. The users’ perceptions about efficacy, time taken and ease of use of the HWT technologies lowered the perceived value attached to the technologies. The assessment of the drinking water quality used by the study communities indicated that the improved sources had a lower geometric mean E. coli and total coliform count than the unimproved sources. Both categories of sources were of poor microbiological quality and both exceeded the Sphere Project (2004) and the WHO (2008) guidelines for total coliforms and E. Coli respectively The study communities’ predominant drinking water sources, surface water and rainwater were faecally contaminated (geometric mean E. coli load of 388.1±30.45 and 38.9±22.35 cfu/100 ml respectively) and needed effective HWT. The improved sources were significantly more likely than the unimproved sources to have a higher proportion of samples that complied with the WHO drinking water guidelines at source, highlighting the importance of providing improved water sources. The lowest levels of faecal contamination were observed between the collection and storage points which coincided with the stage at which HWT is normally applied, suggesting an HWT effect on the water quality. All water sources had nitrate and turbidity levels that exceeded the WHO stipulated guidelines, while some of the improved and unimproved sources had higher than permissible levels of lead, manganese and aluminium. The water source category and the mouth type of the storage container were predictive of the stored water quality. The active treater households had a higher percentage of samples that complied with WHO water quality guidelines for E. coli than inactive treater households in both improved and unimproved source categories. In inactive treater households, 65% of storage container water samples from the improved sources complied with the WHO guidelines in comparison to 72% of the stored water samples in the active treater households. However the differences were not statistically significant. The HWT technologies did not attain sector standards of effective performance: in descending order, the mean log10 reduction in E. coli concentrations after treatment of water from unimproved sources was PUR (log₁₀ 2.0), ceramic filters (log₁₀ 1.57), Aquatab (log₁₀ 1.06) and Waterguard (log₁₀ 0.44). The mean log10 reduction in E. coli after treatment of water from improved sources was Aquatab (log₁₀ 2.3), Waterguard (log₁₀ 1.43), PUR (log₁₀ 0.94) and ceramic filters (log₁₀ 0.16). The HWT technologies reduced the user’s daily exposure to water-borne pathogens from both unimproved and improved drinking water sources. The mean difference in exposure after treatment of water from unimproved sources was ceramic filter (log₁₀ 2.1), Aquatab (log₁₀ 1.9), PUR (log₁₀ 1.5) and Waterguard (log₁₀ 0.9), in descending order. The mean probability of infection with water-borne pathogens (using E.coli as indicator) after consumption of treated water from both improved and unimproved sources was reduced in users of all the HWT technologies. The difference in reduction between technologies was not statistically significant. The study concluded that despite the apparent need for HWT, the study households’ inadequate knowledge, poor attitudes and unhygienic practices make it unlikely that they will use the technologies effectively to reduce microbial concentrations to the standards stipulated by accepted drinking water quality guidelines. The structured method of HWT promotion in the intervention villages had not resulted in more hygienic water and sanitation KAP in the IG compared to the CG, or significant differences in likelihood of adoption and compliance with the assessed HWT technologies. Despite attaching a high perceived value to HWT, insufficient knowledge about how to use the HWT technologies and user concerns about factors such as ease of use, accessibility and time to use will impact negatively on adoption and compliance with HWT, notwithstanding their efficacy during field trials. Even though external support had been withdrawn, the assessed HWT technologies were able improve the quality of household drinking water and reduce the exposure and risk of water-borne infections. However, the improvement in water quality and reduction in risk did not attain sector guidelines, highlighting the need to address the attitudes, practices and design criteria identified in this study which limit the adoption, compliance and effective use of these technologies. These findings have implications for HWT interventions, emphasising the need for practice-based behavioural support alongside technical support.

<div>This dissertation focused on examining the potential unintended consequences of sustainability on drinking water quality at the tap. The rising trend in water conservation awareness has given rise to the use of water-efficient appliances and fixtures for residential potable water systems. The first study (Chapter 1) characterized the microbial dynamics at a water-efficient residential building over the course of one year and examined the effects of water stagnation, season, and changes in physicochemical properties on the occurrence of opportunistic pathogen markers. When rainwater harvesting is utilized as an alternative water resource in buildings, a combination of municipal water and rainwater is typically required to meet water demands. However, altering source water chemistry can disrupt pipe scale and biofilm and negatively impact water quality at the distribution level. The second study (Chapter 2) in this dissertation evaluated the potential water quality consequences of using intermittent supplies of municipal water and rainwater within building plumbing systems. Cross-linked polyethylene (PEX) pipes are considered by some to be more sustainable than copper pipes and are commonly installed in building plumbing. The goal of the third study (Chapter 3) was to better understand chemical release from commercially available PEX pipes, to characterize toxicological characteristics of the contact water, and to compare microbial growth potential among the three pipe types. During the COVID-19 pandemic, many commercial and office buildings were closed for extended periods of time, allowing water age to increase over the course of several months. Heightened water age is often associated with an increase in chemical and microbial contamination. The objective of the fourth study (Chapter 4) was to evaluate the impacts of an extended COVID-19 related building closure and stagnation on water quality. The goal of this study was to evaluate the efficacy of flushing and shock chlorination remediation strategies on water quality at the tap. </div><div><br></div><div>This dissertation contains four chapters and each chapter is a single manuscript. The first two chapters have been published.</div><div><br></div><div>“Drinking water microbiology in a water-efficient building: Stagnation, seasonality, and physiochemical effects on opportunistic pathogen and total bacteria proliferation.” (Chapter 1) Utilizing a residential building that had been retrofitted with low-flow fixtures, the unintended water quality consequences of increased stagnation in low-flow plumbing were evaluated over a year long period. The study results indicated that microbial growth and potential opportunistic pathogen markers, Legionella and Mycobacterium spp. were detected at higher levels within the home as compared to the municipal water main. Reduced water usage induced longer stagnation times and longer stagnation times were correlated with an increase in Legionella spp., Mycobacterium spp., and total cell counts.</div><div><br></div><div>“Impacts of Municipal Water−Rainwater Source Transitions on Microbial and Chemical Water Quality Dynamics at the Tap.” (Chapter 2) Altering source water chemistry can disrupt pipe scale and biofilm and negatively impact water quality at the distribution level. Still, it is unknown if similar reactions occur within building plumbing following a transition in source water quality. To date, no prior studies had evaluated the water quality impacts of transitioning between rainwater and municipal groundwater sources in low-flow plumbing. The study revealed that influent water chemistry impacted rates of metal release from plumbing. Because of differences in source water treatment and water chemistry, rainwater and municipal water uniquely interacted with building plumbing and generated distinctively different drinking water chemical and microbial quality profiles. </div><div><br></div><div>“Contaminant Leaching and Toxicological Assessment of Drinking Water in Contact with Cross-linked Polyethylene (PEX) Pipes.” (Chapter 3) Cross-linked polyethylene (PEX) plastic water pipes are increasingly being installed instead of copper pipes for conventional and green building construction. Unlike metal pipe, PEX pipe is easier to install and not vulnerable to corrosion. However, potential health concerns associated with PEX pipe are: 1.) the organic contaminant release that occurs during its service-life, 2.) increased microbial growth compared to metal pipes, and 3.) compound toxicity. Our study goal was to better understand chemical release from commercially available PEX pipes, to characterize toxicological characteristics of the contact water, and to compare microbial growth potential among the three pipe types at varying chlorine concentrations. Results indicated that PEX contact waters did not affect the neurobehavioral development of zebrafish, but affected development in the zebrafish model. Further studies should be conducted to determine how influent water chemistry impacts carbon migration and the water’s toxicity.</div><div><br></div><div>“Water quality during the COVID-19 pandemic: The role of flushing and shock chlorination strategies in reducing building water problems.” (Chapter 4) The COVID-19 pandemic led to widespread “stay at home” orders across the United States. As a result, many office buildings, schools, and commercial buildings were left empty, allowing water age within the plumbing to increase dramatically. Heightened stagnation and water age can lead to increased metal leaching from pipe walls, as well as increases in microbial growth and opportunistic pathogen proliferation. Water quality in a large school building was monitored after approximately six months of being closed due to COVID-19 related restrictions. Upon sampling the building, chemical and microbial water quality indicators were affected by the initial six month stagnation period. To monitor the relationship between shock chlorination and water quality at the tap, samples were collected at fixtures at different time points to gain a better understanding of the effects of shock disinfection on drinking water chemistry and microbiology. This study raises concerns with respect to the impact of extended building closures on drinking water quality and the best approach to remediate and monitor water quality issues thereafter.</div>

Gram-negative infection has been linked to hospital water although few studies have examined whether water systems are reservoirs of nosocomial pathogens. This study investigated longitudinal recovery of the opportunistic pathogens Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumannii from water outlets of a haematology unit and evaluated Point-Of-Use Filtration (POU-F) as a control measure. In a two-year double cross-over trial, water samples and swabs were taken weekly from 39 showers/taps on the unit. Four study phases alternated between non-filtered (Phases 1 & 3), and filtered outlets (Phases 2 & 4) using Pall AquasafeTM 14-day filters. In Phases 1 & 3; 99% of 1396 samples yielded bacterial growth, with colonies generally too numerous to count. Target species were isolated from 22% of water samples (P. aeruginosa 14%; S. maltophilia 10%) and 10% of swabs. P. aeruginosa was particularly associated with handwash stations and S. maltophilia with showers. A. baumannii was not isolated. With POU-F; 22% of 1242 samples yielded bacterial growth (mean CFU/100ml ,4.6). S. maltophilia was isolated only once from water but never from outlet swabs. PCR typing identified clusters of isolates colonizing different outlets over time but no clear association between water and patient isolates was identified. The incidence of Gram negative infections remained low throughout the study. Without POU-F, water from taps/showers represented a source of bacteria including the target species. POU-F substantially reduced the frequency and number of target species from every outlet, and merits further investigation as an intervention to protect immunocompromised patients from opportunistic pathogens. / School of Life Sciences, University of Bradford and Pall Medical (Pall Europe Ltd)

Thesis (M. Tech. (Environmental Health)) -- Central University of technology, Free State, 2013 / Introduction: Drinking water of poor quality can cause a variety of diseases and may even result in death. The impact of poor drinking water is a course for concern even in South Africa. Therefore, the physical, chemical and microbiological drinking water quality was investigated in the peri-urban area of Bainsvlei and the Woodlands Hills Estate in Bloemfontein, Free State. Materials and Methods: The water quality was assessed in 20 identified sampling sites for three series with ten weeks apart. These sites use treated municipal and untreated borehole water for drinking. The determinants analysed for were pH, electrical conductivity (EC), turbidity, temperature, Ca, Mg, Na, F, Cl, N, SO₄,N, Free chlorine, Al, As, CN, Fe, Mn, Pb, Hg, total coliforms and E. coli. The water samples were collected and analysed on site and in the laboratory. Both the physical and chemical determinants were measured using standard methods whereas the microbiological determinants were measured using the Defined Substrate Technology (DST) method. The measurements were first compared to the SANS 241 (2011) for compliance. The ANOVA tests were used to investigate if any seasonal variations existed in the water quality as well as to compare the levels of the determinants between borehole and municipal water. In the assessment of the overall drinking water quality of different water sampling sites the water quality index (WQI) was used. Results and Discussions: Significant effects were believed to exist if the p-values of the ANOVA and Scheffe tests were at a significance level of 5% (p < 0.05). The study results revealed that of the four physical determinants that were measured turbidity exceeded the standard in many sampling sites in the three series. Of all the chemical determinants, nitrates exceeded the standard. In the same way coliforms exceeded the standard in a number of sampling sites while E. coli was found in a few sampling sites in the first series. ANOVA tests revealed that seasonal variations existed between pH, EC, temperature, cyanide and iron at a significant level of 5% (p < 0.05) while the Post-hoc Scheffe test further revealed the series in which the effect existed. Similarly, the ANOVA tests revealed that the levels of the determinants between municipal versus borehole varied in pH, EC, Ca, Mg, Na, F, Cl, N, and SO₄ at a significant level of 5% (p < 0.05). The WQI showed that in all the series when combining the good and excellent category season 2 had the highest percentage of 80%, followed by season 3 with 79% and season 1 with 70%. Only borehole sampling sites were found in the poor, very poor and unsuitable categories. Similarly all the highest WQI values were found in borehole sampling sites. Conclusion: This study revealed that the water quality is of good quality in the Bainsvlei and Woodlands Hills Estate of the Mangaung metropolitan municipality in Bloemfontein, in the Free State, South Africa. The presence of E. coli, though found in a few sampling sites and the high levels of turbidity, nitrates and coliforms are of concern to public health.

Thesis. (M. Tech. (Dept. of Biosciences, Faculty of Applied and Computer Sciences))--Vaal University of Technology, 2010 / Methods for detecting the presence of Cryptosporidium oocysts and Giardia cysts have been developed and continuous improvement is being done to improve the recovery rate of the target protozoa. Rand Water has adopted their method for isolation and detection of Cryptosporidium oocysts and Giardia cysts in water from United State Environmental Protection Agency (US-EPA) Method 1623, 1999. In 2005 changes were made by US-EPA to the Method 1623. A study was done to improve the performance of the Rand Water Method 06 (2007) used for isolation and detection of Cryptosporidium oocysts and Giardia cysts. Three methods namely: Rand Water Method 06 (2007), US-EPA Method 1623 (2005) and Drinking Water Inspectorate standard operating procedures (2003) were compared and key different steps in the methods were identified (wrist action speed, centrifuge speed, immunomagnetic separation procedures and addition of pre-treatment steps). Different experiments were conducted to verify and evaluate the difference between two wrist action shaker speeds, three different centrifuge speeds, two slightly different immunomagnetic separation procedures and when a pre-treatment step was included in the method. Three different types of water matrices (reagent grade water, drinking water and raw water) were used for the experiments and secondary validation. Data obtained from the experiments and secondary validation was statistically analyzed to determine whether there was a significant difference in the recovery of Cryptosporidium oocysts and Giardia cysts. Secondary validation of the Rand Water Method 06 (2007) was performed by implementing the study experiments‟ findings into the method. The results indicated an increase in the recovery rate of Cryptosporidium oocysts and Giardia cysts when data was compared with the previous secondary validation report. The mean recovery of Cryptosporidium oocysts in reagent grade water samples increased from 31% to 55%, drinking water samples increased from 28% to 44% and raw water decreased from 42% to 29%. The mean recovery of Giardia cysts in reagent grade water samples increased from 31% to 41%, drinking water samples increased from 28% to 46% and raw water decreased from 42% to 32%. Furthermore, even though the recovery rate of raw water decreased the use of pre-treatment buffer reduced the number of IMS performed per sample by reducing the pellet size. Enumeration of microscope slides was also easier as there was less background interference. The optimization of the Rand Water Method 06 (2007) was successful as the recovery rate of Cryptosporidium oocysts and Giardia cysts from water increased. All the changes that were verified and that increased the recovery rate were incorporated into the improved Rand Water Method 06.

Thesis. (M. Tech (Biotechnology, Faculty of Applied and Computer Science))--Vaal University of Technology, 2011. / Bottled water like any drinking water used for human consumption should be safe and wholesome to ensure adequate public health protection. This is due to potential health effects of concern such as endocrine disruption, toxicity teratogenicity, mutagenicity and carcinogenicity. Despite the number of regulatory bodies, publications on bottled water and speculations on its public health significance, many questions remain to be answered. One of the questions is whether the shelf life of bottled water is a cause for concern. The aim of the study was to determine the shelf-life of various commercial bottled waters by monitoring the variation in microbiological, chemical and aesthetic qualities of bottled water. A total of five commercial bottled water brands (A, B, C, D, E) each containing bottles from the same batch consisting of spring water, mineral water and bottled tap water were purchased directly after being bottled from different distributors around Gauteng in South Africa. All samples were stored at room temperature with artificial lighting and controlled temperature for a year thus mimicking typical conditions in retail outlets, supermarkets and in homes. Analyses were conducted over a period of 12 months, at monthly intervals. Within days of being purchased, high Heterotrophic plate counts (HPC) bacteria exceeding drinking water alert level >5 000 cfu/ml was common in four bottled water brands. Growth succession occurred during the period of study as various algal species were growing and accumulating on all bottled water tested. Total coliforms (TC), faecal coliforms (FC) and E.coli were not detected in all the bottled water tested. Yeasts and moulds were also not detected in all the bottled water. There were insignificant variations during the period of study for turbidity, pH, TDS, conductivity, and colour. These did not indicate any potential impact on aesthetic quality of bottled water. Two bottled water brands had hardness measures as low as 11mg/ℓ as CaCO3 making the water too soft which has an effect on taste. Radioactive substances, trihalomethanes, heavy metals, pesticides and other chemical contaminants were not found at levels that can be detrimental to human health.