Private Water Supplies Research Articles

Social dilemmas and poor water quality in household water systems

Abstract. Private water supply systems consisting of a domestic well and septic system are used throughout the world where households lack access to public water supply and sewers. In residential areas with a high housing density, septic contamination of private wells is common and associated with multiple health concerns. This situation can give rise to social dilemmas, where individual costs de-incentivize homeowners from investing in enhanced septic systems that would reduce well contamination and bring communal benefits. We combine a stylized game theoretical model with a probabilistic groundwater model to characterize how economic and hydrogeological conditions interact to produce misaligned incentives conducive to social dilemmas. The occurrence of social dilemmas depends on the relative costs of well contamination versus the cost of installing an enhanced septic treatment system and the relative probabilities of cross-contamination versus self-contamination. The game reveals three types of social dilemmas that occur in such systems, with each calling for distinct policy solutions. We demonstrate how the model can be applied to existing systems, using a case study of St. Joseph County, Indiana, where high nitrate contamination rates have raised public health concerns. This analysis represents a step towards identifying alternative policy solutions for a problem that has remained difficult to address for decades.

Regulatory-Driven Risk Assessment to Improve Drinking-Water Quality: A Case Study of Private Water Supplies in England and Wales

Regulatory-Driven Risk Assessment to Improve Drinking-Water Quality: A Case Study of Private Water Supplies in England and Wales

Application of Correlation and Regression Models in Predicting the Physico-chemical Quality of Groundwater from Insitu Measured Parameters

Groundwater is the major source of municipal and private potable water supply for meeting the drinking, domestic, agricultural and industrial requirements on man around the world. The cost of analyzing water quality in the laboratory to ascertain its potability is usually high and sometimes not available. Groundwater samples were collected from fifty (50) spatially referenced bore well locations in Warri and its environs in the dry and wet seasons (November 2019 to January 2020) in the study area. The water samples were analyzed for twenty-six (26) physical, chemical and bacteriological parameters both in the field and laboratory in line with APHA standard procedures for testing water and waste water inorder to evaluate the status of potability of groundwater across Warri, Delta State Nigeria. The data analysis tool in Microsoft Excel was used to explore and study the interrelationship between some conservative parameters measured in the field (pH, EC, TDS, and DO) as independent variables and some cations, anions and heavy metals (Na, Mg, Ca, HCO3, SO4 Cl, Fe, Cd, Cr, Cu and Pb) analysed in the laboratory as dependent variables. The results obtained from the parameters analysed insitu in the field which are cheap to perform and easily affordable were used to check and evaluate and the inter-relationships with some cations, anions and heavy metals. Highly correlated water quality parameters were determined by correlation coefficient (R) values obtained from correlation matrix and related by Regression equations (models). The regression models can be adopted to predict the concentration of these cations, anions and heavy metals before the rigorous laboratory analysis, to serve as a quick check for concentration of most disease-causing pollutants and to save time, money and resources, especially the near absence of AAS for analysing heavy metals in a good number of laboratories. The regression models developed in the study can be used for monitoring the water quality parameters by knowing the concentration of independent parameters obtained in the field alone. There is a relationship between variables which show that one variable actually causes changes in another variable. It was observed that multiple regression models can predict most parameters at 5% level of significance. Significantly positive correlation at 1 and 5% was found between many parameters. This technique studied and calculated the correlation coefficients between various physico-chemical parameters of drinking water and provided an excellent device for the calculation of parameter values within realistic degree of accuracy. The results proved to be easiest, useful, and rapid means for monitoring of water quality with the help of systematic calculations of correlation coefficient. It is recommended to treat groundwater prior to domestic use.

Application of Correlation and Regression Models in Predicting the Physico-chemical Quality of Groundwater from Insitu Measured Parameters

Groundwater is the major source of municipal and private potable water supply for meeting the drinking, domestic, agricultural and industrial requirements on man around the world. The cost of analyzing water quality in the laboratory to ascertain its potability is usually high and sometimes not available. Groundwater samples were collected from fifty (50) spatially referenced bore well locations in Warri and its environs in the dry and wet seasons (November 2019 to January 2020) in the study area. The water samples were analyzed for twenty-six (26) physical, chemical and bacteriological parameters both in the field and laboratory in line with APHA standard procedures for testing water and waste water inorder to evaluate the status of potability of groundwater across Warri, Delta State Nigeria. The data analysis tool in Microsoft Excel was used to explore and study the interrelationship between some conservative parameters measured in the field (pH, EC, TDS, and DO) as independent variables and some cations, anions and heavy metals (Na, Mg, Ca, HCO3, SO4 Cl, Fe, Cd, Cr, Cu and Pb) analysed in the laboratory as dependent variables. The results obtained from the parameters analysed insitu in the field which are cheap to perform and easily affordable were used to check and evaluate and the inter-relationships with some cations, anions and heavy metals. Highly correlated water quality parameters were determined by correlation coefficient (R) values obtained from correlation matrix and related by Regression equations (models). The regression models can be adopted to predict the concentration of these cations, anions and heavy metals before the rigorous laboratory analysis, to serve as a quick check for concentration of most disease-causing pollutants and to save time, money and resources, especially the near absence of AAS for analysing heavy metals in a good number of laboratories. The regression models developed in the study can be used for monitoring the water quality parameters by knowing the concentration of independent parameters obtained in the field alone. There is a relationship between variables which show that one variable actually causes changes in another variable. It was observed that multiple regression models can predict most parameters at 5% level of significance. Significantly positive correlation at 1 and 5% was found between many parameters. This technique studied and calculated the correlation coefficients between various physico-chemical parameters of drinking water and provided an excellent device for the calculation of parameter values within realistic degree of accuracy. The results proved to be easiest, useful, and rapid means for monitoring of water quality with the help of systematic calculations of correlation coefficient. It is recommended to treat groundwater prior to domestic use.

Economic Research on the Global Allocation of Scarce Water Resources Needs Better Data

Water sustainability is central to modern political and academic debates. Despite increasing efforts to promote regional and global integrated water management, climate change, population, and economic growth, and increasing consumption of water-intensive goods project higher water deficiency. Robust economic analyses rely on information about water supply and consumption across different production sectors, type of procurement source (public or private water supply), and water prices. Nevertheless, developing current and future economic water assessments and indicators is impeded by the absence of data. Despite the lack of official national statistics on water withdrawal and consumption, a small number of international and global databases have been constructed and attempt to combine available national water information into databases. Water databases do not commonly define and/or distinguish terms such as water use, water consumption, water supply, or water abstraction, and the associated aspects of water scarcity and sustainability. They comprise variable data quality, provided by numerous sources, and estimated values. This paper evaluates the current state of knowledge of national statistics, international and global water databases. We describe the data collection methods, identify basic concepts and definitions of water terms, followed by the criteria of consistent water databases. We inform about data availability across regions, and present the data content and definitions of national, international, and global water databases. The results show inconsistencies of data content and definitions, suggesting no evidence of data harmonization among databases. Therefore, our study cautions researchers to be careful when manipulating and comparing the available water data, especially when deriving policy recommendations or economic conclusions. In the long run, the headway of water research and political assessments depend on political enforcements to refine the meaningfulness of water data and support water collection, reporting, and monitoring. Alternatively, in the short- and medium-run, water data challenges can be addressed by joint research efforts for water data harmonization.

Organohalogens: A persisting burden in Slovenia?

Persistent organic pollutants (POPs) represent a concern for the environment and human health due to their persistence and toxicity. Exposure in Slovenia is geographically differentiated because the country, as part of former Yugoslavia, has a history of industry and regional contamination and is – at the same time – known for its clean nature. The PCB pollution of the Krupa River drew the public's attention to the chemical burden of Slovenians, and the demand for studies has been rising since. We assessed the exposure of men (n = 548) and primiparous women (n = 536) to POPs in 12 regions of Slovenia as well as exposure pathways via questionnaires. Most PCDD/Fs, PCBs, and PBDEs could be determined in pooled samples of maternal milk at low concentrations (1.57 pg/gTEQ, 1.47 pg/gTEQ, and 1076 pg/g fat, respectively), but a much lower number of compounds could be measured above the LOQ in pooled men's plasma samples (PCDD/Fs 0.08 pg/gTEQ, PCBs 0.007 pg/gTEQ, ΣPBDE 920 pg/g), and only HCB, p,p’-DDE, ΣDDT, and the non-dioxin-like PCB congeners 138, 153, and 180 could be determined in individual samples of milk (concentration range 5–60 ng/g fat). In individual samples of men's serum, only p,p’-DDE and ΣPCB were detected at concentrations of 0.25 ng/g and 0.3 ng/g, respectively. Nonetheless, we were able to differentiate between polluted and unpolluted areas on a national level, with higher exposure levels in the PCB polluted region of Bela Krajina, the industrial region Zasavje, and the capital, Ljubljana. Despite low concentrations, determinants of exposure, such as age, proximity to roads, old building materials, private water supplies, and consumption of alcohol, fish, meat, and eggs that have previously been observed only at higher levels could still be identified. Furthermore, levels of PCBs and PBDEs were highly correlated suggesting common exposure sources and pathways, whereas PCDD/Fs were correlated to a lesser extent. The calculated ratio between DDT and DDE in maternal milk samples was decreasing with the year of sampling, suggesting no ongoing exposure to DDT. The study findings suggest low exposure of men and lactating women to legacy pollutants in Slovenia, which gave rise to the hypothesis that Slovenia's geographical location might provide shelter from the long-range transport of POPs via Westerly winds. This hypothesis remains to be confirmed within future studies.

CONFLICTS BY WATER RESOURCE USE AND THE CASE OF ARARAQUARA-SP

Abstract This work presents hydric conflicts in Brazil, its causes and effects and the case of conflicts related to the supply and demand of groundwater in the municipality of Araraquara, Brazil. In this municipality, the situation is classified as critical by the Tietê-Jacaré Basin Committee, to which it belongs. The main factors that cause conflicts in Araraquara and the key actors involved were identified. The demands of groundwater users were determined and the users responsible for most of the total demand were identified by the ABC Method. These users, even in small number, are the main potential causers for the conflicts, involving public and private water supply. Public policies related to water resources and conflicts management are also discussed and measures for conflict attenuation are proposed. Such measures should be implemented by key actors and the main groundwater users involved.

Working with community researchers to enhance rural community engagement around Private Water Supplies: an exploration of the benefits and challenges

This project employed community researchers as a means of improving community engagement around their Private Water Supplies (PWS) in rural Scotland. In this paper, we reflect on working with community researchers in terms of the benefits and challenges of the approach for future rural research that seeks to improve community engagement. The paper (1) critiques the involvement of community researchers for rural community engagement, drawing on the experiences in this project and (2) provides suggestions for good practice for working with community researchers in rural communities’ research. We offer some context in terms of the role of community members in research, the importance of PWS, our approach to community researchers, followed by the methodological approach and findings and our conclusions to highlight that community researchers can be beneficial for enhancing community engagement, employability, and social capital. Future community researcher approaches need to be fully funded to ensure core researchers can fulfil their duty of care, which should not stop when data collection is finished. Community researchers need to be supported in two main ways: as continuing faces of the project after the official project end date and to transfer their newly acquired skills to future employment opportunities.

A fatal case of Shiga toxin-producing Escherichia coli linked to a private drinking water supply.

In May 2017, a fatal case of Shiga toxin-producing <i>Escherichia coli</i> (STEC) with haemolytic uremic syndrome was investigated by the Victorian Department of Health and Human Services and a local government authority. Investigation revealed the case used rainwater harvested from the roof of their home and stored in tanks as a private drinking water supply, despite the availability of a reticulated supply from the local water authority. <i>Escherichia coli</I> Stx1 and Stx2 genes were detected in a water sample collected from the private drinking water supply, consistent with those earlier identified in the case’s faecal sample. This case study highlights the potential risks of STEC infection from private drinking water supplies, the importance of proper maintenance of such supplies, and the preferable use of reticulated water supplies when available. It also demonstrated an effective collaboration between local and state government for an environmental public health investigation.

Establishing and extending EPHT capacity in England: governance and operational aspects

Within Public Health England (PHE), an Environmental Public Health Tracking (EPHT) programme was established that includes several activities on surveillance of environmental hazards, exposures and health outcomes. We aim to account for key aspects of EPHT governance and operations in England. We describe the process for selecting topics to be included in EPHT and managing its data. This core infrastructure of EPHT within PHE has delivered capacity to support activities on ongoing concerns regarding hazardous pollutants and chemicals in drinking water, land, food and air, as well as linking with novel interpretative frameworks derived from research programmes in collaboration with external research groups. The English EPHT programme has adopted an approach providing common governance for disparate themes, this includes a EPHT board accountable to PHE’s executive via an environmental hazards programme board, a strategic advisory group, stakeholder consultations, and PHE working groups with the remit to establish surveillance structures and functions appropriate to specific information needs. This process has produced activities on population exposure estimation of arsenic in private water supplies, the burden of disease of carbon monoxide poisoning, lead exposure in children, fluoridation monitoring, and guidance for investigating non-infectious disease clusters from potential environmental causes. Recent developments include national systems for enhanced air pollution exposure surveillance and access to weather data for public health use. Studies of distribution of vectors, climate variability and infectious disease, coastal changes and toxin-producing algae, social factors affecting use of green spaces and related health benefits, all illustrate novel interpretative frameworks that were first tested and documented in a research setting, and having been co-designed and co-produced with public health agencies, their relevance for EPHT can more easily be considered. In conclusion, EPHT in England is a programme that enables both activities on well-known environmental factors, and the capacity to integrate emerging concerns.

Challenges of private provision of potable water in Obio/Akpor Local Government Area and its Socio-economic implications

Water is a basic and necessary requirement for the existence of animals and plants, yet it is limited in supply in several parts of the world. Surges in human population and demand for water for different purposes such as agricultural, domestic and industrial usages are the major factors leading to water scarcity. Nigeria and the study area are blessed with abundant water resources including surface and groundwater, yet there is a palpable lack of adequate and safe potable water. Consequently, the populace resorts to private sources of water supply which has its negative externalities even though the effort seems laudable. Based on the above, the study examined the proliferation of private water supply, its challenges and socio-economic implications in Obio /Akpor local government area. The study adopted a cross-sectional survey, and data were collected with the use of both closed and open-ended questionnaire. It also involved the collection of the private borehole points with the use of a handheld global positioning system (GPS). Data were analyzed using the descriptive method of analysis and data presented in charts and tables. The result of the study showed that there were no specific distances maintained between borehole points, a good number of borehole locations were clustered in some parts of the study area. Also, distances between soakaway pits and borehole points were inadequate in some communities. Based on the prevalent minimum wage in the study area, both households that operate boreholes and those that buy water spent more. Some of the socio-economic implications of private provision of water supply include too much spending on water, creation of livelihoods for water vendors and vulnerability to waterborne disease such as typhoid since there is no minimum standard for borehole drilling and distance in the study area. The study recommended that the government should develop a private borehole drilling standard that would include the minimum distance that must be maintained between two boreholes on vertical and horizontal lines. Also, the activities of the private water vendors should be regulated, and operating license obtained before operating commercial boreholes. The study concluded thus, there should be a synergy between the private and public sector to ensure safe and affordable water supply since their activities cannot be undermined.

Sensibilidade a antibióticos e metais pesados em Escherichia coli e Klebsiella pneumoniae isoladas de diferentes fontes de água do Cariri Cearense, Brasil

A resistência a agentes antimicrobianos e metais pesados é resultado da consequência natural da adaptação celular bacteriana à exposição desses contaminantes no ambiente. A investigação da sensibilidade bacteriana a contaminantes ambientais é necessária especialmente devido ao reconhecimento dos impactos que esses podem causar. O presente trabalho isolou cepas de Escherichia coli e Klebsiella pneumoniae de diferentes ambientes aquáticos da Bacia do Salgado - CE e avaliou a sua sensibilidade a antimicrobianos e metais pesados. Doze cepas bacterianas foram isoladas e identificadas e a sensibilidade foi avaliada pelo método de microdiluição em caldo, com as concentrações variando entre 0,49 – 250 μg/mL para os metais pesados cobre e cromo e 0,25 – 128 μg/mL para os antimicrobianos imipenem, meropenem e ceftriaxona. As cepas de Klebsiella pneumoniae demonstraram sensibilidade à ação do imipenem e meropenem, já para a ceftriaxona constatou-se que as cepas provenientes das águas de abastecimento apresentaram maior resistência para esse antimicrobiano. O meropenem foi o antimicrobiano para o qual as bactérias demonstraram maior sensibilidade. Em relação aos metais pesados, as cepas de E. coli de água de abastecimento apresentaram ser mais resistentes que as demais. As cepas de K. pneumoniae demonstraram maior tolerância que as de E. coli para os metais. Além disso, todas as estirpes, de ambas as espécies, apresentaram concentração inibitória mínima inferiores aos valores reportados pela literatura para o cobre e cromo. A menor tolerância aos metais pesados se refletiu na sensibilidade para os antimicrobianos. Os resultados desse estudo exibem perfil de sensibilidade a antimicrobianos e metais pesados adequados sob a perspectiva da saúde pública, todavia, requer atenção sobre a microbiota aquática desses ambientes.

English

Due to the erratic nature of microbial contaminants in drinking water, private and municipality water supply systems failed to deliver safe drinking water to households. In Ethiopia, there is lack of data and knowledge on the effectiveness of filter devices used to treat drinking water at household. This study aims to evaluate efficiency of household point of use filter devices (membrane filter, membrane with activated carbon, ceramic candle type filter and hybrid (multistage)) in reducing bacterial contaminants from drinking water. Percent reduction efficiency model was employed in evaluating bacterial removal efficiency. Membrane filter and membrane with activated carbon filter devices had good total coliform removal efficiency on the 1st and 2nd days than hybrid filter device which showed low removal efficiency. Similarly, all filter devices showed better fecal coliform removal efficiency on the 1st day compared to 2nd day but had low heterotrophic bacteria removal efficiency during the three days filtration. Fecal Streptococcus removal efficiency on the 2nd and 3rd days by all filter devices was low except the first day. The result in general showed that using of point of use filter devices for prolonged time could not guarantee in providing risk free drinking water at household level. Key words: Coliform, drinking water, household filters, point of use, removal efficiency.

Quality of drinking water in Kathmandu valley, Nepal

Present study was undertaken to analyze drinking water quality of Kathmandu valley with the estimation of essential minerals of public health concern. Twenty water samples of each source, viz. public water supply, private water supply, and processed drinking water supply, were randomly collected. Sample analysis was carried out for physical (temperature, pH, and electrical conductivity), chemical (calcium, magnesium, sodium, and potassium), and microbiological (total coliform—TC) parameters. It was found that the physical parameters such as temperature, pH, and electrical conductivity (EC) were within the World Health Organization (WHO) drinking water quality guidelines. Generally, for all the water sources the average concentration of calcium was below the WHO drinking water quality guidelines as well as DRI (Dietary Reference Index) recommendations. Moreover, the concentration of magnesium, sodium, and potassium was also found below the DRI recommendations for all the water sources. Microbiological parameter enumerated for TC in processed drinking water depicted bacterial population from 0 CFU/100 mL to 46 CFU/100 mL. The presence of TC in processed drinking water makes the water unacceptable for drinking purpose, although the physical parameters were almost within the WHO drinking water quality guidelines. The presence of required amount of minerals plays a critical role in maintaining human health system and vitality. Therefore, this study explores the quality of drinking water in the Kathmandu valley in terms of minerals and TC bacteria.

ENVIRONMENTAL CONSIDERATIONS OF LARGE WASTEWATER TREATMENT PLANTS – THE CITY OF NIŠ CASE STUDY

Nowadays, the Republic of Serbia is at the bottom of the scale of European countries in terms of public utility equipment of the respective communal infrastructure particularly within the area of wastewater collection and treatment. The current situation in the area of water resources management in the Republic of Serbia indicates that the basic problems are insufficient construction of sewerage infrastructure in cities, i.e. insufficient coverage with the sewerage network of users connected to either public or private water supply network, followed by an insufficient number of constructed and operative wastewater treatment plants. In this sense, a particular problem is a requirement for relatively large initial investments in wastewater collection and treatment sector. Also, a special difficulty is the low price of delivered and channeled water within the existing system of public utilities, which is insufficient to provide maintenance of the existing water supply and sewage systems, regardless the future development and improvement of the existing system. Currently, only 10% of total produced wastewater quantity is treated in the Republic of Serbia, with different procedures and with uneven and, most often, insufficient purification effects. In addition to wastewater generated by the population (i.e. households connected to the sewer system), the special problem is the inadequate treatment of industrial wastewater. On the other hand, disposition of treated wastewater, disposal of separated sludge from the treatment process, odor and pest control, noise control, working conditions, etc. are significant challenges for the scientists, professionals and operators. Therefore, the aim of this paper is to comprehensively examine all environmental aspects on the example of a large wastewater treatment plant which is to be gained by the city of Niš, in the very near future.

A Study of Risk Factors related to Water and Sanitation in Pune, west India

Background: Piped water systems are considered to be the gold standard for drinking water according to the Joint Water Monitoring Study. However, poor maintenance of distribution pipes, intermittency of water supply, and sewage water intrusion have contributed to a number of water-borne disease episodes in developed and developing countries. Methods: This study investigated the risk burden related to drinking water and sanitation in population clusters of Pune, western India that are being served by a piped distribution system through a cross-sectional survey. Two-stage stratified convenience sampling was carried out. The city was divided into administrative wards of which the city center, the neo-urban and the peri-urban settlement were selected. In the second step a higher (HSG) and a lower socioeconomic group (LSG) were selected from each of the three studied wards. A questionnaire including close-ended items was used to conduct the survey. Results: In 2711 individuals studied, risk burden related to drinking water and sanitation was found to be higher in the LSG; 60% (677 of 1121), 70% (1029 of 1473) , 74% (1325 of 1791) from the LSGs did not have a private water tap and continuous water supply, and did not treat the water at the household level, respectively. 98% (1403 of 1426) had neither a private water tap nor a private sanitary facility. The socioeconomic difference was significant (p<0.0001). 51 (3.5%) individuals from the LSGs and 42 (3.49%) ones from HSGs reported having suffered from severe diarrhea in the recall period of 2 years. Although the number of disease cases was lower than the overall risk burden, the potential of the latter to cause a disease outbreak cannot be eliminated. Conclusion: The study highlights that piped drinking water system which is considered as a safe source can become a source of pathogenic microorganisms if not properly maintained. A holistic approach to risk assessment, i.e., from the catchment and its source water to the consumer, is required.

Factors influencing perceptions of private water quality in North America: a systematic review

BackgroundAn estimated four million and 43 million people in Canada and the USA use private water supplies. Private water supplies are vulnerable to waterborne disease outbreaks. Private water supplies in Canada and the USA are often unregulated and private water management is often a choice left to the owner. Perceptions of water quality become important in influencing the adoption of private water stewardship practices, therefore safeguarding public health.MethodsWe conducted a systematic literature review to understand factors that shape perceptions of water quality among private water users. We searched six computer databases (Web of science, Medline, Scopus, EBSCO, PubMed and Agricola). The search was limited to primary peer-reviewed publications, grey literature and excluded conference proceedings, review articles, and non-peer review articles. We restricted the search to papers published in English and to articles which published data on surveys of private water users within Canada and the USA. The search was also restricted to publications from 1986 to 2017. The literature search generated 36,478 records. Two hundred and four full text were reviewed.ResultsFifty-two articles were included in the final review. Several factors were found to influence perceptions of water quality including organoleptic preferences, chemical and microbiological contaminants, perceived risks, water well infrastructure, past experience with water quality, external information, demographics, in addition to the values, attitudes, and beliefs held by well owners.ConclusionsUnderstanding the factors that shape perceptions of water quality among private water users is an important step in developing private water management policies to increase compliance towards water testing and treatment in Canada and the USA. As many jurisdictions in Canada and the USA do not have mandatory private water testing or treatment guidelines, delineating these factors is an important step in informing future research and guiding policy on the public health of private water systems.

El abastecimiento de agua a Barcelona (1850-1936): Origen y desarrollo de las compañías privadas

En este trabajo se analiza el papel que jugaron las empresas privadas de abastecimiento de agua potable en la modernización de la ciudad de Barcelona durante las últimas décadas del XIX y las primeras del siglo XX. La necesidad de extender una novedosa y completa red de abastecimiento de agua, obligó a la búsqueda de soluciones legales, técnicas y urbanísticas. Prosperidad industrial y crecimiento de la población se dieron la mano en la creación de una ciudad cada vez más populosa y moderna. Este conjunto de acciones desembocó en el diseño de redes que configuraron la traza de la nueva ciudad, al mismo tiempo que propiciaron la aparición de empresas que pugnaron -entre ellas y con el Ayuntamiento-, por el dominio y el control del mercado.

Electrically heatable carbon nanotube point-of-use filters for effective separation and in-situ inactivation of Legionella pneumophila

Despite municipal chlorination and secondary disinfection, opportunistic waterborne pathogens (e.g., Legionella spp.) persist in public and private water distribution systems. As a potential source of healthcare-acquired infections, this warrants development of novel pathogen removal and inactivation systems. In this study, electrically heatable carbon nanotube (CNT) point-of-use (POU) filters have been designed to remove and inactivate Legionella pneumophila in water. The CNT/polymer composite membranes effectively removed Legionella (>99.99%) (i.e., below detection limit) and were able to inactive them on the membrane surface at 100% efficiency within 60 s using ohmic heating at 20 V. The novel POU filters could be used as a final barrier to provide efficient rejection of pathogens and thereby simultaneously eliminate microorganisms in public and private water supplies.

Bayesian Hierarchical Models as Tools to Evaluate the Association Between Groundwater Quality and the Occurrence of Type 2 Diabetes in Rural Saskatchewan, Canada.

There is growing interest in the role of environmental exposures in the development of diabetes. Previous studies in rural Saskatchewan have raised concerns over drinking water contaminants, including arsenic, which has been identified as a possible risk factor for diabetes. Using administrative health and water-quality surveillance data from rural Saskatchewan, an ecological study design was used to investigate associations between concentrations of arsenic, water health standards and aesthetic objectives, and the incidence and prevalence of diabetes. Mixtures of contaminants measured as health standards or as aesthetic objectives were summarized using principal component (PC) analysis. Associations were modeled using Bayesian hierarchical models incorporating both spatial and unstructured random effects, standardized for age and sex, and adjusted for socioeconomic factors and a surrogate measure for smoking rates. Arsenic was not associated with an increased risk of diabetes. For private wells, having groundwater arsenic concentrations in the highest quintile was associated with decreased cumulative diabetes incidence for 2010-2012 (risk ratio [RR] = 0.854, 95% credible interval [CrI] 0.761-0.958) compared with the lowest quintile, a result inconsistent with other studies. For public water supplies, having a first PC score for health standards (primarily summarized selenium, nitrate, and lead) in the third quintile (RR = 1.101, 95% CrI 1.019-1.188), fourth quintile (RR = 1.088, 95% CrI 1.003-1.180), or fifth quintile (RR = 1.115, 95% CrI 1.026-1.213) was associated with an increase in 2010 diabetes prevalence compared with the first quintile. An increase in the PC scores for the third aesthetic objective in private wells (characterized primarily by iron and manganese) was associated with decreased diabetes incidence, although a meaningful dose-response relationship was not evident. No other associations between PC scores for health standards or aesthetic objectives from public or private water supplies and diabetes were identified.