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    Global assessment of chemical quality of drinking water: The case of trihalomethanes
    (Elsevier Ltd, 15/02/2023) Villanueva CM; Evlampidou I; Ibrahim F; Donat-Vargas C; Valentin A; Tugulea A-M; Echigo S; Jovanovic D; Lebedev AT; Lemus-Pérez M; Rodriguez-Susa M; Luzati A; de Cássia Dos Santos Nery T; Pastén PA; Quiñones M; Regli S; Weisman R; Dong S; Ha M; Phattarapattamawong S; Manasfi T; Shaibu-Imodagbe EM; Eng A; Janák K; Rush SC; Reckhow D; Krasner SW; Vineis P; Richardson SD; Kogevinas M
    BACKGROUND: Trihalomethanes (THM), a major class of disinfection by-products, are widespread and are associated with adverse health effects. We conducted a global evaluation of current THM regulations and concentrations in drinking water. METHODS: We included 120 countries (∼7000 million inhabitants in 2016), representing 94% of the world population. We searched for country regulations and THM routine monitoring data using a questionnaire addressed to referent contacts. Scientific and gray literature was reviewed where contacts were not identified or declined participation. We obtained or estimated annual average THM concentrations, weighted to the population served when possible. RESULTS: Drinking water regulations were ascertained for 116/120 (97%) countries, with 89/116 (77%) including THM regulations. Routine monitoring was implemented in 47/89 (53%) of countries with THM regulations. THM data with a varying population coverage was obtained for 69/120 (58%) countries consisting of ∼5600 million inhabitants (76% of world's population in 2016). Population coverage was ≥90% in 14 countries, mostly in the Global North, 50-89% in 19 countries, 11-49% among 21 countries, and ≤10% in 14 countries including India, China, Russian Federation and Nigeria (40% of world's population). DISCUSSION: An enormous gap exists in THM regulatory status, routine monitoring practice, reporting and data availability among countries, especially between high- vs. low- and middle-income countries (LMICs). More efforts are warranted to regulate and systematically assess chemical quality of drinking water, centralize, harmonize, and openly report data, particularly in LMICs.
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    Self-assembled optical diffraction sensor for water quality monitoring : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering, Massey University, Albany, New Zealand
    (Massey University, 2020) Jaywant, Swapna
    Water contamination is one of the current global issues; the freshwater sources being extremely restricted are causing a drinking water crisis in many countries. An increase in water contamination continuously decreases water quality. Generally, water pollution includes pathogenic, nutrients, and chemical (organic & inorganic) contaminants. Inorganic contamination involves metallic particles such as arsenic, lead, etc. Of these contaminants, arsenic (As) is a major concern due to its mutagenic and carcinogenic effects on human health. The World Health Organisation has recommended the maximum contamination limit (MCL) for arsenic in drinking water to be 10 µg/L. Countries like Bangladesh, China, Vietnam, India, Chile, USA, and Canada are contaminated with arsenic. Arsenic species are also found in New Zealand in 28 geothermal features from the Taupo Volcanic Zone and the Waikato region. Thus, a rising level of arsenic in drinking water creates the need to periodically monitor its levels in potable water. Commercially available methods are either laboratory-based or kit based techniques. The most common laboratory-based arsenic detection methods are reliable. However, these are expensive due to the requirement for specific instrumentation. Hence, they are not considered to be field-effective for arsenic detection. On the other hand, commercially available kit-based methods are portable but are not considered to be safe and reliable due to the production of toxic by-products. The development of a portable and sensitive arsenic sensor with high throughput could be an asset. In this research, we present a novel sensor with a unique surface modification technique to detect arsenite (As(III)) contamination of water. Here, the approach involves the potential usage of self-assembled optical diffraction patterns of a thiol compound (dithiothreitol or glutathione) on the gold-coated glass. The self-assembled patterns are obtained through a microcontact printing (µCP) procedure. Gold binds with the thiol compound through an Au-S linkage. In addition to this, As(III) has an affinity towards amino acids, amines, peptides, and organic micro molecules due to As-O or As-S linkages. The research indicates that the total time taken by the µCP process to transfer the patterns successfully on to the gold-coated substrate is inversely proportional to the concentration of the thiol molecules and pH value of the solvent. Further, the signal enhancement of these thiol-based self-assembled patterns allows for detection of the As(III) contamination. Simultaneously, the automated fluidic system is designed to provide fluid handling. The system is developed with the help of off-the-shelf and/or in-house fabricated components. The characterisation of fluidic components proved that the low-cost fluidic components work reliably in the fluidic network and can be used in sensing applications for pumping, mixing, and circulation purposes. We also explore the possibility of using fused deposition modelling and selective laser sintering technology for the printing of the flow chamber through printing microchannels. These two technologies have been compared in terms of the minimum possible channel size, fluid ow-rate, and leakage. Overall, we developed a sensing scheme of a portable self-assembled diffraction sensor for As(III) detection. The developed sensor can detect dissolved As(III) up to 20 µg/L. The µCP of a dithiothreitol pattern has not been found in the literature yet. Hence, this research also provides a guide towards µCP of dithiothreitol on a gold-coated substrate.
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    A study of the bacteriological quality of bottled and tap water in Cebu City, Philippines : a thesis presented in partial fulfilment of the requirements for the degree of Master of Environmental Management at Massey University, Manawatu, New Zealand
    (Massey University, 2014) Ybanez, Bryan B
    A study was conducted in the mega urban centre of Cebu City, Philippines between July and October 2013, with the aim of assessing the bacteriological quality of bottled and tap drinking waters. The study was performed during the warm, rainy season, when prevalence of diarrhoea linked to bacterial contamination of water supply is usually at its highest level in tropical countries. The bacteriological tests performed on the water samples were: isolation of E. coli, thermotolerant coliforms, total coliforms, and heterotrophic plate counts. In addition, sanitation programs applied by bottled water manufacturers and the local water system supplier were surveyed by means of a questionnaire. The study focussed on bottled water brands with the greatest combined market share in the study area, and the household taps surveyed were located in villages with the greatest number of local water supply concessionaires. The results indicated the presence of bacteria in both bottled and tap water samples. A considerable number of bottled water samples from one brand were positive for heterotrophic plate count bacteria. On the other hand, positive tap water samples collected from one household were positive for E. coli, thermotolerant coliforms, total coliforms, and the HPC bacteria. Multivariable Poisson regression modelling indicated a significant variability in heterotrophic bacterial counts between production batches of bottled water. For the tap water samples, statistical analysis was not indicated because all contaminated samples belonged to a single household tap and were collected on one sampling occasion. In regard to sanitation programs, the municipal water supplier and all except one bottled water manufacturer reported the application of Good Manufacturing Practice and Quality Control programs in the production plant. Interestingly, the only bottled water manufacturer which did not respond to the survey questionnaire manufactured the only brand consistently showing positive bacterial counts and failing the Philippine regulatory standards. It is concluded that a number of factors associated with bacterial contamination in the study area require close monitoring by bottled water manufacturers, water suppliers, and health authorities.
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    A comparison of the microbiological quality of drinking-water of urban and semi-urban dwellings in the Richmond district of New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Environmental Health Science at Massey University, Wellington, New Zealand
    (Massey University, 2013) Thompson, Lucy Ann
    This study aimed to determine if residents of Richmond, Nelson, with an on-demand, mains pressure, and metered drinking-water supply had the same microbiological drinking-water quality at the kitchen tap as dwellings with a restricted, low-flow supply. Both dwelling types were supplied with water from the same untreated, reticulated water supply scheme. The results from this study provide information for both consumers and the supplier regarding the microbiological quality of drinking-water supplied at the kitchen tap. A cross-sectional, interviewer administered survey of 50 dwellings with a metered supply and 61 dwellings with a restrictor supply was conducted during May-July 2012. Microbiological water quality of each dwelling was ascertained by testing water samples from the kitchen tap for the presence of indicator organisms, using the Colilert®-18 method. When total coliforms were used as an indicator, metered dwellings did not have the same water quality as restrictor-only dwellings (p<0.0005): more restrictor-only dwellings were contaminated than metered dwellings. Drinking-water at the kitchen tap for 84% of metered dwellings and 48% of restrictor-only dwellings complied with the microbiological criteria set in the DWSNZ 2005 (Revised 2008) of <1 total coliform per 100 ml. When E.coli was used as an indicator, metered dwellings were found to have the same water quality as restrictor-only dwellings (p=0.242). Drinking-water for all metered dwellings and 94% of restrictor-only dwellings complied with the microbiological criteria set in the DWSNZ 2005 (Revised 2008) of <1 E.coli per 100 ml. Supplementing the reticulated water supply with water from another source was undertaken by 18% of participants with a restrictor supply and it appeared to cause a reduction in the microbiological quality of drinking-water. The results for E.coli have demonstrated that it is possible to provide a potable supply of drinking-water from an untreated, reticulated supply to dwellings with either a metered or a restrictor-only supply. The total coliform results indicated that there might be issues with the use of restrictor drinking-water supplies, in particular the use of private water storage systems. Owners of restrictor supplies need to be provided with more information on the set-up, design, and maintenance of these water storage systems.
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    MDes project report : Watermakers - desalination and hydration at sea
    (Massey University, 2011) D'Anvers, Phillip John; D'Anvers, Phillip John
    In this exegesis the term Watermaker has been used to describe a survival product that creates fresh potable drinking water from saltwater. Of all the water on the earth ninety seven percent of it is saltwater. Of that three percent that is fresh water only point five percent is of a quality safe enough for drinking (Kim, Hee Ko, Kang, & Han. 2010). When a person is stranded on a life vessel or in a situation where freshwater is not readily available, a survival product that produces fresh water has the possibility of prolonging the life of that person. Designing a product that provides fresh water and thus preventing the dehydration of someone in a survival situation was the aim of this project. The final product meets the design criteria of being energy efficient and easy to use. By achieving this, the end user is provided with a product that is immediately usable and requires a low expenditure of energy when in use. Product testing and usability studies were carried out during development to ensure that the design criteria were fulfilled. Research revealed that there is a need for a product of this kind that sits in the more affordable end of the market. Design challenges involved creating a product that requires minimal parts and keeps manufacturing costs low. Achieving this resulted in a more affordable option to the consumer, with the intention of making them more inclined to purchase the product that may some day save their life. Furthermore, low cost can open up opportunities in markets that would otherwise have been precluded by price sensitivity, such as in developing nations. Of the two main desalination processes in use today (reverse osmosis and distillation), distillation was chosen as it offered more affordable design options and production methods. This product is unique in its function of using the sun’s energy to gather water through condensation. Utilising the suns energy to generate fresh water made this product more suited for warmer climates; however testing showed it was still productive in cooler climates. A product of this nature could be used in any situation where fresh, potable water is required – not just survival circumstances. With water shortage and quality becoming a global concern this product offers a low cost, easy to use option for producing drinking water. Over 80% of the global third world population is situated within the tropics. The low cost of this product coupled with the warmer temperatures found in the tropics means this product is ideally suited for use in developing nations