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Membrane hybrid processes--coagulation coupled with ultrafiltration (UF)--have become a common method to comply with the legal, chemical, and microbiological requirements for drinking water. The main advantages of integrating coagulation with membrane filtration are the enhanced removal of natural organic matter (NOM) and reduced membrane fouling. With in-line coagulation, coagulants are patched into the feed stream directly prior to the membrane process, without removing the coagulated solids. Compared with conventional coagulation/sedimentation, in-line coagulation/membrane reduces the treatment time and footprint. Coagulant dosing could be challenging in raw water of varying quality; however, with relatively stable specific ultraviolet absorbance (SUVA), dosing can be controlled. Recent studies indicate that UV absorbance correlates well with humic substances (HS), the major fraction to be removed during coagulation. This paper describes and evaluates a 30-month UF pilot trial on the surface water of Lake Neden (Sweden), providing drinking water to 60,000 residents. In this study, automatic coagulant dosing based on online measurement was successfully applied. Online sensor data were used to identify the current optimal aluminium coagulation conditions (0.5-0.7 mg L-1) and the potential boundaries (0.9-1.2 mg L-1) for efficient future (2040) NOM removal. The potential increase in NOM could affect the Al dose and drinking water quality significantly within 20 years, should the current trends in dissolved organic carbon (DOC) prevail. UV absorbance, the freshness index, and liquid chromatography-organic carbon detection (LC-OCD) measurements were used to optimise the process. Careful cross-calibration of raw and filtered samples is recommended when using online sensor data for process optimisation, even in low-turbidity water (formazin nephelometric unit (FNU) < 5). [ABSTRACT FROM AUTHOR]

Customers primarily perceive the safety of drinking water on aesthetic qualities. Chlorine, geosmin and 2-methylisoborneol (2-MIB) are common causes of taste and odour complaints in Australia. Variance in customer preference, perception, cultural differences and individual experiences make regulation of these, in the form of guidelines, challenging to establish. Here, analysis of historical water quality and customer complaint data showed the use of customer complaints as an indicator of deteriorating water quality is not robust. The use of a modified Flavour Ratings Assessment showed a statistical decrease in customer acceptance from control samples when chlorine concentration in drinking water increased above 0.2 mg/L and when geosmin or 2-MIB concentration was greater than 10 ng/L. However, geosmin was only rated 'unacceptable' at 30 ng/L while chlorine and 2-MIB were not rated 'unacceptable' for the range tested. For all samples, including 'blanks', customers indicated a greater tendency to complain in a social setting rather than formally to their water provider. [ABSTRACT FROM AUTHOR]

Perception of tastes and odors in water is a major interest for water producers and distributors because off-flavors in tap water are associated with health risk by consumers. However, the taste of water is difficult to describe due to the medium itself which is supposed to have no taste. Classical sensory methodologies are difficult to adapt and only get part of the whole perception. This study suggests a new approach to qualify and quantify taste of water using multiple physiological measurements to go back up the perception chain. The four basic tastes (sweet, salty, acid and bitter) were used and diluted in Evian water as a standard, at low concentrations. Autonomic system responses were measured with skin blood flow variations. Results from skin blood flow variations are presented and indicate a high correlation between the duration and amplitude of the response with the self-reported intensity and pleasantness of the stimulus. It also shows that physiological measurements enable the significant discrimination of the different tastes even at detection threshold concentrations. The prediction of the characteristics of a stimulus might be obtained by combining multiple physiological data and sensory responses. [ABSTRACT FROM AUTHOR]

Chlorinous flavors are a leading cause of customers' dissatisfaction with drinking water. Potential differences in chlorine perception were investigated by conducting sensory testing experiments in France and Spain to assess consumers' sensory sensitivity (chlorine flavor detection threshold and supra-threshold intensity) as well as their liking of and acceptability for chlorinated solutions. In both countries, two groups of panelists were constituted based on their water drinking habits (tap vs. bottled water). Chlorine flavor detection threshold was found to vary depending on countries (0.17 mg/L Cl² in France and 0.56 mg/L Cl² in Spain). Taking into account that mean flavor detection thresholds were found in agreement with chlorine residuals delivered at tap, it is likely that habituation may explain sensitivity differences between countries. This hypothesis is supported by results showing no significant sensitivity difference at detection threshold levels, but significant differences between tap water and bottled water consumers at supra-threshold levels (flavor intensity). In addition, consumers' liking and acceptability for chlorinated water was found to be in agreement with sensitivity: the higher the sensitivity the lower the acceptability for chlorinated waters. Thus, French consumers or bottled water drinkers showed a lower appreciation of chlorinated water solutions and were especially less inclined to accept chlorinated water as drinking water delivered at tap. [ABSTRACT FROM AUTHOR]

Abstract: Studies have shown that drinking water of good sensory quality have total dissolved solid (TDS) concentrations between 100 and 450mgL−1. However, such studies have only investigated the overall sensory quality of water and not the different sensory attributes. Little is known about the taste and mouthfeel attributes of drinking water in relation to the chemical composition. The purpose of this study was to determine the variation in sensory attributes of Danish drinking water and the relation to the chemical composition. Groundwater samples were collected from 20 waterworks with uplands and aquifer reservoirs characteristics covering the main variation in geochemistry and land use. The groundwater samples' inorganic chemical composition was determined and a trained panel determined sensory attributes and their intensities. Identified sensory attributes listed with decreasing intensity were: moist, fresh, salty, chalky, hard, astringent, metallic, bitter, sweet and sour. The main sensory variation between samples was caused by the saltiness and this attribute was negatively correlated to all other impressions especially moistening. The saltiness had a strong linear positive correlation to the TDS, conductivity and Na concentration (R2 =0.72–0.92) whereas the descriptor fresh was negatively linear correlated to these parameters (R2 =0.76–0.81). The descriptors, fresh and moist, seem mainly to be a result of low salt concentrations which characterises samples from aquifers at the glacial outwash plains of western Jutland and elevated seabeds of northern Jutland. [Copyright &y& Elsevier]

The article discusses the contamination warning system (CWS) pilot program in Cincinnati, Ohio. It says that operational response actions such as distribution system isolation should be implemented when a contamination incident happen, to lessen potential economic and public health impacts. It states that a positive analytical result is a reliable way to confirm a contamination incident. It adds that public notification of drinking water quality incidents offers a way to protect public health.

Abstract: Describing the taste of water is a challenge since drinking water is supposed to have almost no taste. In this study, different classical sensory methodologies have been applied in order to assess sensory characteristics of water and have been compared: sensory profiling, Temporal Dominance of Sensations and free sorting task. These methodologies present drawbacks: sensory profile and TDS do not provide an effective discrimination of the taste of water and the free sorting task is efficient but does not enable data aggregation. A new methodology based on comparison with a set of references and named “Polarized Sensory Positioning” (PSP) has been developed enabling to easily define the sensory characteristics of water without presenting too many samples. Finally, this method provides a new type of sensory data requesting dedicated data analysis. [ABSTRACT FROM AUTHOR]

With the increasing demands for water due to increasing population, urbanization and agricultural expansion, groundwater resources are gaining much attention, particularly in the Kandi region of Jammu district, which faces acute shortages of drinking water throughout the year. Groundwater development programmes need a large volume of data from various sources. This study used integrated remote sensing and geographic information system (GIS) techniques to provide an appropriate platform for convergent analysis of multidisciplinary data and decision making for artificial recharge to groundwater. Thematic maps were constructed using merged Linear Imaging Self Scanner (LISS)-III and Panchromatic (PAN) remote sensing data and aquifer parameter thematic layers were prepared from conventional field data. The thematic layers of the aquifer parameters were integrated and a map showing the potential zones for artificial recharge to groundwater was generated. By superimposing the drainage network map over this artificial recharge zone map, and also considering the terrain conditions for artificial recharge, suitable sites for replenishing groundwater in the study area were identified. [ABSTRACT FROM AUTHOR]

2-Methylisoborneol (MIB) and geosmin (GSM) are taste and odor compounds produced by cyanobacteria in surface waters. While the strong odors and musty flavors of MIB and GSM are generally associated with poor water quality, the removal of these semi-volatile compounds presents a significant challenge to drinking water providers. Likewise in aquaculture, accumulation of these compounds in fish meat leads to quality problems and reduces marketability. Conventional water treatments are ineffective at removing low concentration of odor compounds. We report herein ultrasonic irradiation at 640kHz leads to rapid degradation of MIB and GSM. While radical processes generally dominate during ultrasonic-induced degradation, pyrolysis appears to be responsible for a significant fraction of the observed degradation. Several pyrolytic products from MIB and GSM have been identified and degradation pathways are elucidated. The degradation of MIB and GSM follows the first-order kinetics and the rate constants are 0.07 and 0.12min−1, respectively. These results suggest ultrasonic irradiation maybe applicable as an effective method for removal of taint compounds from potable water supplies and fish farms. [Copyright &y& Elsevier]

The ozonation of 2-methylisoborneol (MIB) and geosmin was investigated in both pure and raw water. In a semi-batch reactor, a series of experiments was performed to determine the effect of pH on the ozonation of MIB and geosmin. The results show that pH has a significant effect on the ozonation of both compounds, which supports the theory that OH radical plays an important role on the destruction of MIB and geosmin. Compared with MIB, geosmin is more readily destroyed by ozonation. The ozonation kinetics follow approximately a first-order equation with respect to MIB and geosmin at the pH of 5, 7 and 9, and their rate orders of CO3 at pH 7 are 0.44 and 0.61, respectively. Ozonation of organic matters in the water decreases the ozone concentration leading to a lower removal of MIB and geosmin; at the same time, the formation of OH radical initiated by the organic matters accelerates the ozonation of MIB and geosmin. The ozonation of MIB and geosmin spiked in raw water, settled water and pure water shows that background organics have no significant effect on the removal of MIB and geosmin; hence, the simplified rate equations acquired in pure water may have potential application in real water. [ABSTRACT FROM AUTHOR]

The article presents an instructional material on the taste of drinking water.

Salty taste with or without chlorine or chloramine flavour is one of the major consumer complaints to water utilities. The flavour profile analysis (FPA) taste panel method determined the average taste threshold concentration for salt (NaCI) in Milli-Q water to be 640 ± 3 mg/L at pH 8, Chlorine and chloramine disinfectants have no antagonistic or synergistic effects on the taste of NaCI, salt, in Milli-Q water. The flavour threshold concentrations for chlorine or chloramine in Milli-Q water alone or in the presence of NaCl could not be estimated by the Weber-Fechner curves due to the chlorine or chloramine flavour outliers in the 0.2-0.8 mg/L concentration range. Apparently, NaCI is not equilibrated with the concentration of ions in the saliva in the mouth and the concentration of free chlorine or chloramines cannot be tasted correctly. Therefore, dechlorinated tap water may be the best background water to use for a particular drinking water evaluation of chlorine and chloramine thresholds. Laboratory FPA studies of free chlorine found that a 67% dilution of Central Arizona Project (CAP) (Tucson, AZ) water with Milli-Q water was required to reduce the free chlorine flavour to a threshold value instead of a theoretical value of 80% (Krasner and Barren, 1980). No synergistic effect was found for chlorine flavour on the dilution of CAP water with Milli-Q water. When Central Avra Valley (AVRA) groundwater was used for the dilution of CAP water, a synergistic effect of the TDS present was observed for the chlorine flavour. Apparently, the actual mineral content of drinking water, and not just NaCI in Milti-Q water, is needed for comparative flavour tests for chlorine and chloramines. [ABSTRACT FROM AUTHOR]

More than 130 years of research has focused on removing acute and chronic health threats to produce safe drinking water, but limited research has focused the consequences of removing minerals that affect drinking water taste and health. This paper covers the human sense of taste, typical variations in drinking water taste, comparisons of global taste standards, the role of water chemistry and future research needs for understanding consumer preference, Results of several consumer tap and bottled water acceptability investigations conducted by the authors are presented. [ABSTRACT FROM AUTHOR]

Customers are sensitive to the flavour of water. Customers evaluate drinking water based on their expectations, on experiences with their usual drinking water and on experiences with alternative waters, The Philadelphia Water Department provides one example of success in developing a better understanding of customer perceptions and attitudes about tap water taste and odour. Philadelphia found first customers do communicate in ways that water utilities can understand, Water utilities can enhance that communication and collect useful data. In addition, water utilities can characterise their tap water flavour, track it for changes and correlate changes to customer complaints. [ABSTRACT FROM AUTHOR]

A detailed review of drinking water disease outbreaks over the past 30 years in 15 affluent countries produced over 70 case studies, some involving fatalities, which revealed a number of common factors in these disasters, Some of these outbreaks involved off-flavours, either as a driver for reducing disinfection and making the system vulnerable to pathogenic contamination or as an early warning of contamination that was not responded to with sufficient urgency or efficiency to avoid a disease outbreak. The characteristics of these outbreaks are recounted and the important link they reveal between aesthetically pleasing drinking water and safety is documented. Our analysis of common features in drinking water outbreaks also supports an argument that the failure of a water utility to be concerned about aesthetic factors makes such water supplies an inherently greater health risk for their consumers. [ABSTRACT FROM AUTHOR]

Methyl tertiary butyl ether (MTBE) is a gasoline additive that has been found in groundwater when an underground gasoline storage tank leaks. Although dependent on the clean-up standards that are applied, clean-up costs have been estimated in the US alone to be in the billions of dollars. MTBE is considered primarily a taste and odour concern and not a toxicity issue at concentrations found in drinking water. Thus, the clean-up of MTBE problems is controlled by the MTBE odour threshold concentration (OTC). The level of clean-up and associated differential of millions of dollars is a matter of concern for water purveyors and well owners. A 1993 study of nine OTC studies showed the OTC of MTBE in water to be between 0.04 and 0.06 pg/L, a level over two orders of magnitude less than eight other studies. This 1993 study was repeated at the original laboratory in 2004 and is reported in this paper. The laboratory's quality control programme and ability to repeat one of the eight other studies indicated the laboratory was qualified to repeat its original OTC study. The flavour and odour detection threshold range in the 1993 study, however, could not be confirmed by trained assessors repeating the original study in 2004. The inconsistencies in the data and the high detection on water blanks indicate that the dilution series of the test solutions for the 1993 study were mainly at subthreshold levels. Therefore, the original study of 1993 is not a valid OTC study for MTBE and should not be used to develop drinking water and clean-up standards. The OTG of MTBE is over 15 µg/L for the eight valid studies. [ABSTRACT FROM AUTHOR]

In this research, methodology was developed to identify locations vulnerable to taste and odour problems in a distribution system. The methodology was based on a multicriteria procedure combining spatial information on consumer complaints and popular perception of tap water. The first step in the described methodology consisted of mapping complaints regarding tap water made by the population between 2002 and 2004 using a geographical information system (GIS). The second step consisted of analysing results of a questionnaire-based mail survey, also through GIS, The information generated using the above steps was integrated using a multicriteria and spatial approach allowing segregation of the distribution system into delineated zones, according to their vulnerability to occurrences of taste and odour problems. The identification of vulnerable sectors in a distribution system will help water managers to implement a better-targeted water quality monitoring programme -- one that considers odours and tastes of drinking water - within the management process. [ABSTRACT FROM AUTHOR]

Mixed chlorobromoanisoles have recently been recognized as new potential odorous compounds in tap water. The odour threshold concentrations (OTCs) of these compounds are close to the sub ng/L (ppt) and associated descriptors are "earthy, musty, rubber". During a "swampy, musty" episode in water of the Norrtälje district (Sweden), 2,4,6-mixed chlorobromoanisoles and their phenolic precursors were identified. These compounds were synthesised in order to quantify them in different types of waters, Samplings were performed during two different seasons. Results show that whatever the season, mixed haloanisoles and their precursors were present. Chlorination, biofilm activity and residence time in the distribution system seem to be critical factors for the appearance of such compounds. [ABSTRACT FROM AUTHOR]

This paper details the analytical strategy that was used to understand the origin of an acute taste and odour episode that induced the temporary shutdown of a plant serving several million customers in South America. The odour of the drinking water was described by local people as "olive odour". The odour of a first sample was described as green apple, fruity and olive oil by CIRSEE panellists. LLE and CLSAGC/ MS showed that the sample contained high levels of 2,4-ditertbutylphenol. When submitted to olfactory- GC/MS, the LLE extract revealed the presence of an intense sweet-fruity odour that did not match any of the MS peaks. Investigation of a second, more concentrated sample collected during the peak of the episode finally revealed that this main odour was due to 2-ethyl-5,5-dimethyl-1,3-dioxane (2EDD). The cis and trans isomers of 2-ethyl-4-methyl-1,3-dioxolane (2EMD) were also identified, together with a variety of plastic additives or oligomers. These compounds had been spilled by a polyester resin manufacturing plant. The characteristics of these episodes are compared with the rare similar episodes previously reported in the literature. [ABSTRACT FROM AUTHOR]

The main, relevant, solved problems associated with taste and odour incidents in Barcelona's drinking water area in the last 14 years are reviewed. Events produced by creosote, dioxanes and dioxolanes, dicylopentadiene, and diacetyl, among the anthropogenic compounds; geosmin, MIB and iodinated trihalomethanes and chlorobromoanisoles as examples of compounds of natural origin are exemplified. The determination of the odour threshold concentrations of selected odorous compounds is also shown as a tool to gain a better knowledge of future taste and odour events. [ABSTRACT FROM AUTHOR]

The Llobregat River is a basic drinking water resource for the city of Barcelona, meeting 40% of the demand, The river runs through a densely populated industrial area, so that it has in its history experienced various episodes due to industrial spills. The present work deals with a recent episode involving diacetyl. To the best of our knowledge this episode is the first time that this compound has been identified as an odour-causing compound in water, In a previous work the analytical method used for the identification of the compound causing the episode was described. The present work focuses its attention on how the episode was handled: action taken at the Sant Joan Despi water treatment plant and the sampling strategy on the river that led to the identification of the company responsible for the spill, a paper mill. It also deals with the role played by the FPA panel in the resolution of the episode: organoleptic description of samples of the problem in the initial phase of the episode (from the treatment plant, distribution network and customer complaints) and, once the compound responsible was identified, the determination of its organoleptic characteristics (odour threshold, odour descriptors, Weber-Fechner curve). [ABSTRACT FROM AUTHOR]

A commonly used plastic plumbing pipe, silane-cross-linked polyethylene (PEX-b according to European standards), was investigated using the Utility Quick Test (UQT), which is a migration/leaching protocol recommended for evaluating taste-and-odour properties of materials prior to installation in distribution systems. After exposure of new PEX pipe to chlorine, monochloramine or no disinfectant, the odours in the leachate were described as "chlorinous" if chlorine or monochloramine were present and "chemical/solvent-like" with descriptors of sweet, bitter, chemical, solvent, plastic, burnt and mechanical/motor oil. The presence of disinfectant, chlorine or chloramines, did not alter the odour characteristics or intensity of the PEX odour. The "chemical/solvent-like" odours persisted even after multiple flushing periods. 2-Ethoxy-2-methylpropane, commonly called ETBE, was identified as a contributor to the described odour from the PEX pipe. Aqueous concentrations of ETBE in pipe leachate ranged from a low of 23 µg/L to > 100 µg/L. The concentrations decreased with increased flushing. Panelists were able to smell ETBE at a concentration of 5 µg/L and assigned a rating of a weak odour. The need for taste and odour testing of plumbing materials prior to use in residential housing systems is necessary. [ABSTRACT FROM AUTHOR]

A study of the production of odour-causing compounds was conducted from the leaching of polyvinylchloride (PVC) pipe and its joints, primer and cement, into drinking water distribution systems. Flavour Profile Analysis (FPA), closed-loop stripping analysis -- gas chromatography/mass spectrometry (CLSA-GC/MS) and sensory-GC analysis of white or grey PVC alone found no odour-causing compounds produced during the leaching experiments. FPA analysis of the PVC's primer and cement leached alone and/or when applied to grey or white PVC pipes produced a glue/varnish odour. A sweet/phenolic odour replaced the glue/varnish odour after the leached media were diluted with Milli-Q water to threshold odour intensity. Three compounds were responsible for the sweet/phenolic odour and were observed by sensory- GC analysis. The leaching study of the PVC pipe with its joint solvents (primer and cement) concluded that the original solvent compounds, and their reaction products that formed during the bonding process on the PVC pipe, were a primary source of the glue/varnish odour. The original compounds of the PVC primer and cement were not detected by CLSA-GC/MS, due to their high volatility during the CLSA extraction method and/or these compounds appeared in a solvent peak of the GC/MS analysis. However, the original primer and cement chemicals (acetone, tetrahydrofuran, methyl ethyl ketone, and cyclohexanone) had a glue/varnish odour. A total of nine odorous GO peaks were produced as reaction products from leaching of primer in water and white or grey PVC; pipe with primer and cement, and white or grey PVC with primer only. None of these compounds were among the chemical ingredients in the original primer or cement. Four GC peaks with a sweet/phenolic odour were present due to the reaction products of the cement leached with white or grey PVC. None of these compounds were positively identified. [ABSTRACT FROM AUTHOR]

Taste and odour problems of tap water in Seoul are attributed to 2-methylisoborneol (2-MIB) and trans-1, 10-dimethyl-trans-9 decalol (geosmin), which are the result of metabolism of algae and chlorine for disinfection. This study was carried out to measure 2-MIB and geosmin in the raw water from the Han River, to investigate removal efficiency of GAC and BAG integrated with post-ozonation, and to minimise and quantify the required chlorine concentration as a final disinfectant through the candidate process. [ABSTRACT FROM AUTHOR]

The formation of bromophenols during chlorination of phenol and bromide-containing waters can be critical for taste and odour problems in drinking waters. The work performed has confirmed that flavour threshold concentrations of some bromophenols are in the ng/L range. In addition, under typical drinking water conditions, kinetic experiments and model simulations performed have shown that (1) bromination is the predominant reaction pathway, (2) bromophenol reaction kinetics are rapid leading to taste-and-odour episodes that last for short periods of 10-20 min, (3) increasing phenol concentration and pH tends to increase taste and odour intensity, (4) increasing chlorine or bromide concentrations tends to shorten the duration of the taste-and-odour episode. [ABSTRACT FROM AUTHOR]

The presence of unpleasant taste and odour in drinking water is an ongoing aesthetic concern for water providers worldwide. The need for a sensitive and robust method capable of analysis in both natural and treated waters is essential for early detection of taste and odour events. The purpose of this study was to develop and optimise a fast stir bar sorptive extraction (SBSE) method for the analysis of geosmin and 2-methylisobomeol (MIB) in both natural water and drinking water. Limits of detection with the optimised fast method (45 min extraction time at 60°C using 24 µL stir bars) were 1.1 ng/L for geosmin and 4.2 ng/L for 1 MIB. Relative standard deviations at the detection limits were under 17% for both compounds. Use of multiple stir bars can be used to decrease the detection limits further. The use of 25% NaCI and 5% methanol sample modifiers decreased the experimental recoveries, Likewise, addition of 1 mg/L and 1.5 mg/L NaOCI decreased the recoveries and this effect was not reversed by addition of 10% thiosulphate, The optimised method was used to measure geosmin concentrations in treated and untreated drinking water. MIB concentrations were below the detection limits in these waters. [ABSTRACT FROM AUTHOR]

Free-choice profiling (FCP) was carried out in order to investigate how naive consumers (who had never tried the product before) described and perceived passion-fruit juice. This method allows participants to use their own attributes to describe and quantify food products and beverages. The study used four different samples of passion-fruit juice, analyzed by 10 consumers in three replicates. The data were analyzed by using generalized Procrustes analysis. The first and second dimension accounted for 78.7% of the variance. The product consensus configuration revealed that assessors were able to reproduce samples’ description, and also to differentiate samples. Free-choice profiling is a useful method for describing consumer perception of passion-fruit juice. [ABSTRACT FROM AUTHOR]

A quick and easy way to monitor the performance of individual sensory assessors during long-term fishery projects was presented. By serving the same product as a reference before each session, assessors could easily recapitulate the descriptors and recalibrate their evaluations to the same scale. No drifting was found during an evaluation period of 19 months, and this was a result of the continuous use of the reference. Serving the reference as an unknown sample made it possible to monitor the performance of the panel. Multivariate data analytical techniques allowed for quick calculations, and results were easily interpreted with the visual layout. Assessors differing from the rest of the panel could be quickly identified as well as the descriptors involved in the deviations. Three assessors were found to use different parts of the scale than the main panel, and one assessor evaluated one descriptor differently than the average panel. After correction for level effect, no difference existed between assessors. [ABSTRACT FROM AUTHOR]

Presents information on the article "Rapid Analytical techniques for Drinking Water Security Investigations," by States et al, which provided an assessment of available techniques for rapid field screening of water for the presence of harmful, toxic, or pathogenic agents. Diagnostic sensitivity; Diagnostic specificity; Positive predictive value.

Focuses on the blind taste test conducted by municipal water supplier Birmingham Water Works in which its tap water beat its bottled and distilled counterparts. Criteria for rating each water sample; Importance of the result of the taste test to the tap water market; Reason behind the popularity of bottled water over tap water.

This article gives a concise summary of the position reached by tastes and odours research in recent decades, and highlights nine key challenges for further investigation. [ABSTRACT FROM AUTHOR]

The pH dependence of the taste of alkaline electrolyzed water (AEW) made by electrolyzing bottled mineral waters was examined by sensory evaluation. For water with a calcium concentration of 79 or 93 mg/L, the taste of AEW with a pH of 9.5 was considered better than that of the unelectrolyzed water. In contrast, for water with a calcium concentration of 10 mg/L, the taste of the unelectrolyzed water was preferred to that of AEW with a pH of 9.5. Electrolysis reduced the calcium concentrations in waters with calcium concentrations of 79 or 93 mg/L, but did not change the calcium concentration in water with a calcium concentration of 10 mg/L. Electrolysis probably improved the taste of water with a higher calcium concentration by reducing the calcium concentration; however, the effect of electrolysis on water with a calcium concentration of 10 mg/L is likely to be the result of the pH increase alone. [ABSTRACT FROM AUTHOR]

BSTRACT Dietary intake is the main source of silicon for humans. The essentiality of silicon for man has not been clearly established, and no suitable data are available for the establishment of a tolerable upper intake level. Recently, a few cases of silica stones in subjects not ingesting trisilicate antacid have been reported, as well as 1 case of renal silica calculi in a 10-mo-old boy, ascribed to the silicate-rich mineral water used to dilute milk. The purpose of this study was to collect extensive data on the silicon content of mineral water that could be combined with data on different foods to study the overall intake of silicon in the diet and to evaluate the potential risk associated with a high intake of this element. Results relating to 207 brands of mineral water show a low silicon concentration (<10 mg/L) in 77% of samples, with the highest levels (>25 mg/L) occurring primarily in water from volcanic areas. The contribution of mineral water to the total consumption of silicon was calculated, considering both the average intake of water by the Italian population and the recommended intake. When the estimated daily intake with solid foods and other beverages was added, the intake was in the range of 45 to 69 mg/d for a consumption of 700 mL of water and 48 to 99 mg/d for a consumption of 1500 mL of water. These values are near or above the upper limit of the typical dietary intake of 20 to 50 mg silicon/d, which is regarded as unlikely to cause adverse effects. The assumption of silicon by newborns deserves particular attention, in view of their special sensitivity and of a reported case of urinary silica calculi in an infant. The levels of silicon we found never reached the value found in the case described. [ABSTRACT FROM AUTHOR]