News Items

Simple kits for detection of indicator bacteria using simple colorimetric and electrochemical methods. (Posted 14/03/2017)
Workers in the United States have developed simple transparency-based electrochemical and paper-based colorimetric analytic detection platforms as complementary methods for food and waterborne bacteria detection from a single assay. Using enzymes long established for identifying E. coli and enterococci low concentrations (101 CFU/mL) of pathogenic and nonpathogenic E. coli isolates and (100 CFU/mL) E. faecalis and E. faecium strains were detected within 4 and 8 h of pre-enrichment. The methodology is not sensitive enough for direct monitoring of drinking water.

MPN method for Legionella enumeration (Posted 14/03/2017)
Legionella pneumophila is an opportunistic pathogen of major concern. The current large volume quantitative method employs membrane filtration (MF) and selective culture on GVPC agar followed by confirmation of isolates by serology (ISO 11731-2). A recent study compared the performance of a novel MPN method (Legiolert/Quanti-Tray) with the ISO 11731-2 membrane filtration method for the enumeration of Legionella pneumophila from 100 ml potable water and related samples. Data from a multi-laboratory study analysed according to ISO 17994 showed that Legiolert™/Quanti-Tray® yielded on average higher counts of L. pneumophila. The Legiolert medium had a high specificity of 96·4%. The new method represents a significant improvement in the enumeration of L. pneumophila from drinking water-related samples.

WHO review of turbidity (Posted 02/03/2016)
WHO has published a technical brief providing information on the uses and significance of turbidity in source water and drinking-water. Practical guidance is provided on the implications of turbidity for water safety at each step of the water supply chain, from catchment through to the point of use.

WHO Guidelines for Drinking Water Quality- First Addendum (Posted 02/03/2016)
WHO has re-issued the 4th Edition of Guidelines for Drinking Water Quality integrated with the first addendum previously issued separately in 2016. ( full updated guidelines) The changes arising from the addendum are separately documented (addendum changes)

Chemical background documents for the development of the Guidelines for drinking-water quality (Posted 02/03/2016)
WHO has recently published new or revised background documents for selected chemical hazards in drinking-water, which informed the development of the recently published first addendum to the fourth edition of the WHO’s GDWQ. These chemicals include (use hyperlink for more information): barium; bentazone; chlorine dioxide, chlorate and chlorite; dichlorvos; dicofol; diquat; lead; MCPA; nitrate and nitrite; and perchlorate.

Removal of enteric viruses and possible surrogates by membrane filtration (Posted 02/03/2016)
Japanese workers have evaluated the removal of three human enteric viruses and one murine surrogate by direct microfiltration and ultrafiltration. They also compared the removal of these with the removal of two bacteriophages (MS2 and φX174) and pepper mild mottle virus (PMMoV). They concluded that PMMoV appears to be a suitable surrogate for human enteric viruses for the assessment of the efficacy of membrane filtration processes to remove viruses, whereas MS2 and φX174 do not.

Flow cytometry as an alternative to heterotrophic plate counts. (Posted 22/02/2017)
A grroup of Belgian, Dutch and Swiss workers have published a second paper supporting the use of flow cytometry (FC) as a more rapid tool for testing water mains after repair than the conventional heterotrophic plate counts.(HPC). When water mains are opened it is customary to carry out HPC and wait until counts from the main and the flushing water are the same before returning to supply.. FC and HPC do not directly correlate since FC counts include the 99%+ of microorganism which are not cultivatable by HPC but FC can give results within 15 minutes of receipt in the laboratory rather than the 18hr+ needed for HPC. Mains cleared by FC for return to supply were subsequently shown to meet the criteria set by HPC. The authors contend that FCM provides a faster, more descriptive and more representative quantification of bacterial abundance in drinking water. ( see also previous item “Flow cytometry for follow-up of water mains after maintenance”)

Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system (Posted 22/02/2017)
A recent Chinese study showed that sulfate could trigger heavy metal release from iron corrosion scales and strong correlations exist between the releases of total iron and heavy metals. In experimental pipe loops heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW).

This may have implications for changes in source of supply to a network


Safe drinking water and waterborne outbreaks (Posted 06/02/2017)
A recent paper in the Journal of Water and Health has reviewed published details of waterborne disease outbreaks between 2000 and 2014. The main causes for contamination were: for groundwater, intrusion of animal faeces or wastewater due to heavy rain; in surface water, discharge of wastewater into the water source and increased turbidity and colour; at treatment plants, malfunctioning of the disinfection equipment; and for distribution systems, cross-connections, pipe breaks and wastewater intrusion into the network. Pathogens causing the largest number of affected consumers were Cryptosporidium, norovirus, Giardia, Campylobacter, and rotavirus.

Neonatal heart defects and DBPs (Posted 06/02/2017)
A case-control study carried out in Massachusetts looked at 904 babies with nonchromosomal congenital anomalies of the heart and circulatory system and individually matched 10 controls per each case from all live births based on week of conception, for a total study population of 9,944. The very detailed paper showed a number of significant associations between certain specific birth defects and certain DBPs.

Elimination of Naegleria fowleri from bulk water and biofilm (Posted 06/02/2017)
Although primary amoebic encephalitis caused by Naegleria fowleri can only be contracted by inhalation, its presence in drinking water is still of concern and at least one fatality has been associated with drinking water. The amoeba requires warm water around 25°C and is unlikely to present a threat in public water supplies in the UK. A recent Australian study has shown that a concentration of 1mg/l of chlorine is sufficient to eliminate Naegleria fowleri from a drinking water system and prevent re-colonisation.

Water hardness and cardiovascular disease (Posted 06/02/2017)
Since at least the 1970s there have been a large number of studies exploring the possible association between drinking water hardness and heart disease (CVD) with no definitive conclusion except that more studies are needed. There has nevertheless been a general acceptance that hard water may have a protective effect in relation to cardiovascular disease. After a review of 643 potential studies studies a meta-analysis of 7 studies was carried out by Italian workers. The study concludes that hard water consumption seems to be protective against CVD. However, the high heterogeneity (I2 = 75.24, p-value = 0.001 for calcium; I2 = 72.96, p-value = 0.0024 for magnesium) and the existence of publication bias limits the robustness and generalizability of these findings. Unsurprisingly it suggests that further high-quality studies are needed to reproduce and confirm these results.

Waterborne outbreaks of protozoal infections. (Posted 06/02/2017)
A review of waterborne outbreaks of protozoal infections between 2011 and 2016 has been published. At least 381 outbreaks attributed to waterborne transmission of parasitic protozoa were documented during this time period. The nearly half (49%) of reports occurred in New Zealand, 45% in North America and 6% in Europe. The most common etiological agent was Cryptosporidium spp., reported in 63% (240) of the outbreaks, while Giardia spp. was mentioned in 37% (141). No outbreaks attributed to other parasitic protozoa were reported. The review notes that countries most likely to be affected lack adequate surveillance systems and many more outbreaks are likely to have occurred.

New DBPs in tap water. (Posted 06/02/2017)
A Chinese study has demonstrated 13 new polar phenolic chlorinated and brominated disinfection byproducts (Cl- and Br-DBPs) in simulated chlorinated drinking water. Disinfectant, contact time, and pH all affected the formation of the 13 new DBPs and gallic acid was confirmed to be the precursor of all 13. 12 of the 13 new DBPs were detected in 16 tap water samples obtained from major cities in East China, at total levels from 9.5 to 329.8 ng/L. The concentrations of the new DBPs were higher in samples with source waters containing higher bromide levels.

Novel multifunctional composite material removes a wide range of impurities from water. (Posted 24/01/2017)
A team of Spanish and German workers have developed a novel material which can remove a wide range of contaminants from water. It is a supported ionic liquid phase (SILP) composite where a polyoxometalate-ionic liquid (POM-IL) is immobilized on porous silica, giving the heterogeneous SILP. The water-insoluble POM-IL is composed of antimicrobial alkylammonium cations and lacunary polyoxometalate anions with heavy-metal binding sites. The lipophilicity of the POM-IL enables adsorption of organic contaminants. The silica support can bind radionuclides.

Guide to water competition (Posted 16/01/2017)
EDIE has produced a useful free water retail competition guide outlining new legislation which comes into force on 1st April 2017.

Flow cytometry for follow-up of water mains after maintenance (Posted 16/01/2017)
Belgian workers have compared the use of flow cytometry (FCM) with conventional bacterial plate counts for determing when a repaired main was fit to return to service. FCM proved to be a more conservative test than plating, yet it yielded immediate results whereas conventional plate counting required at least 24 hours. Application of these FCM methods can therefore avoid long unnecessary waiting times and large drinking water losses.

Potential gene-based tool for pathogen detection in environmentaal samples (Posted 10/01/2017)
Nucleic acid sequence-based amplification (NASBA) is a sensitive and efficient molecular tool for amplification of RNA and has been widely adopted in clinical diagnostics. NASBA has qualities that should be advantageous for analysis of environmental samples, such as short reaction times, high sensitivity, and not readily affected by inhibitory substances that are often abundant in environmental samples. This review explores advantages and drawbacks of NASBA as a tool for environmental analyses. (wikipedia)

Evaluating UV-C LED disinfection performance (Posted 10/01/2017)
A dual-wavelength UV-C LED unit, emitting at peaks of 260 nm, 280 nm, and the combination of 260|280 nm together was evaluated for its inactivation efficacy and energy efficiency at disinfecting Escherichia coli, MS2 coliphage, human adenovirus type 2 (HAdV2), and Bacillus pumilus spores, compared to conventional low-pressure and medium-pressure UV mercury vapor lamps All sources were equally effective for E.coli. While the 260nm LEDwas most effective for MS2, the medium pressure UV was most effective for HAdV2 and Bacillus pumilus. For UV-C LEDs to match the electrical efficiency per order of log reduction of conventional LP UV sources, they must reach efficiencies of 25–39% or be improved on by smart reactor design.

Impact of fracking on drinking water resources (Posted 10/01/2017)
USEPA has released a review of available scientific information concerning the relationship between hydraulic fracturing activities and drinking water resources in the United States. The review found scientific evidence that hydraulic fracturing activities can impact drinking water resources under some circumstances. Because of data gaps and uncertainties, it was not possible to fully characterize the severity or frequency of impacts.

Businesses offered one-stop-shop for energy and water. (Posted 22/12/2016)
A new partnership will offer a ‘one-stop-shop’ for businesses to secure deals for their energy and water consumption all in a single place. Scotland's incumbent water retailer Business Stream will manage the water services of the new multi-utility offering, while consultancy firm Utilitywise will oversee energy provision.

The all-in-one utility service will initially be available to all organisations in Scotland, before being introduced to companies in England when the water retail market opens for competition in April 2017.

Business Stream – which will manage the water services – and Utilitywise – which will oversee energy provision – are hoping to engage small and medium-sized businesses (SMEs) with the new offering, as they may not have dedicated procurement teams or the weight of a large company to agree preferential rates with energy suppliers. The introduction of a one-stop utility offer comes as the water industry prepares for retail competition to be introduced for non-domestic water customers in England in April next year. The Government-led water retail competition strategy will effectively allow businesses to switch suppliers of water retail services; opening the water and wastewater (sewerage) retail market to new water companies and encouraging greater innovation within the water sector.

Inactivation of E. coli by copper and silver wire in the presence of synthetic sunlight for safe drinking water (Posted 22/12/2016)
Laboratory studies using a pure culture of E.coli compared the use of copper wire, artificial sunlight, both separately and in combination, and silver wire for the inactivation of the bacteria in water.. The studies showed that an improved rate of bacterial inactivation was achieved using the combined Cu/sunlight treatment method compared to either treatment applied independently. When given independently, the Ag wire treatment was more effective than the Cu wire treatment. Unfortunately the combination of silver wire and sunlight was not investigated. ( This work needs to be taken forward to a real world scenario before the authors claim that copper/sunlight combination method has a great potential to be used as a low-cost, re-useable, low-maintenance method of choice for purification of contaminated drinking water can be validated)

Removal of Cr(VI) from water by electrocoagulation (Posted 22/12/2016)
There is growing concern over Cr(VI) in drinking water and future legislation is a possibility. US workers have shown that passing an electric current between iron electrodes can effect the reduction of mutagenic Cr(VI) in water to relatively harmless Cr(III).

Pathogenic features of heterotrophic plate count bacteria (HPC) from drinking-water boreholes (Posted 22/12/2016)
A recent paper looked at the pathogenic potential of HPCs from untreated borehole water used for humen consumption by determining haemolytic properties and a range of relevant enzymes.and antibiotic sensitivity profile.They also looked at effect on a tissue culture cell line. They concluded that that the prevailing standards for HPCs in drinking water may expose humans with compromised immune systems to undue risk.

Discover Water launched (Posted 08/12/2016)
Discover Water is a collaborative project which gives a comprehensive range of data covering water quality, public health, customer service and environmental aspects of water and sewerage services.. Led and funded by water companies, it has been delivered by an independent third party and overseen by a sector-wide group, including the sector’s regulators and consumer watchdog. The information used on Discover Water is already separately published by water companies, Ofwat, Defra, Drinking Water Inspectorate, Environment Agency and the Consumer Council for Water.

Background papers on drinking water and groundwater. (Posted 08/12/2016)
The upcoming WileyInternational Encyclopedia on Geography will include very detailed and informative sections looking at global groundwater resources and their exploitation and also global availability, distribution of, and access to drinking water.

Removal of Naegleria fowleri from a drinking water distribution system (Posted 07/12/2016)
Workers in Australia have shown that a concentration of 1mg/l of chlorine was sufficient to eradicate Naegleria fowleri from both the bulk water and biofilm in a drinking water distribution system and prevent recolonisation.

Virus removal requirement for potable use of recycled water (Posted 07/12/2016)
A discussion paper suggests that the conventionally accepted 12 log reduction for safe use of recycled water for drinking may be too lax and a further 2 log could be appropriate.

Review of Health Outcome Targets (Posted 18/11/2016)
UKWIR has published a “Review of health outcome targets adopted worldwide for assessing the microbiological safety of drinking water”. The review looks at 7 countries and concludes that there is a variety of approaches. Some countries use Disability Adjusted Life Years (DALY)as a metric while others prefer Level of Risk of Infection. Both approaches require some measure of the pathogen burden and while Quantitatve Risk Assessment (QMRA) is invariably used there is no standard framework for the exercise and different approaches have been used which vary in their complexity.

Direct DOC and nitrate determination in water using dual pathlength and second derivative UV spectrophotometry (Posted 18/11/2016)
A recent paper in Water Research describes how it is possible to measure simultaneously both dissolved organic carbon (DOC) and nitrate in water without the need for filtration. Based on several hundred samples from a number of samll rivers, comparison between the proposed method and the standardised procedures for nitrate and DOC measurement gave a good agreement for both parameters for ranges of 2–100 mg/L nitrate and 1–30 mg/L DOC.

Managing discolouration risk in trunk mains (Posteb 29/10/2016)
A recent paper assesses the applicability of cohesive layer theories to manage discolouration and describes a steady state empirical modelling tool that describes the process of particulate material accumulation. Results from independent field experiments across the UK and internationally showed hydraulically induced mobilisation, or effectively cleaning, once imposed system shear stress exceeds normal conditions. The experiments highlighted the accumulation of material layers as a continuous and ubiquitous process, such that fully clean pipes can never exist and help explain how discolouration risk changes over time. A major practical implication of the novel understanding demonstrated in the paper is that discolouration risk in trunk mains can be simply managed by pro-active strategies that regularly vary the hydraulic conditions. This avoids the need for disruptive and expensive out of service invasive interventions yet offers operators a cost-effective long-term strategy to safeguard water quality.

Efficacy of water treatment processes and endemic gastrointestinal illness (Posted 20/10/2016)
A Swedish paper examines endemic AGI ( acute gastrointestinal illness) and the relationship with pathogen elimination efficacy in public drinking water treatment processes. Data of all telephone calls to the Swedish National Healthcare Guide between November 2007 and February 2014 from twenty Swedish cities were obtained and calls concerning vomiting, diarrhea or abdominal pain (AGI calls) were separated from other concerns (non-AGI calls). Information on which type of microbial barriers each drinking water treatment plant in these cities have been used were obtained, together with the barriers’ theoretical pathogen log reduction efficacy. To achieve one general efficacy parameter for each plant, a weighted mean value of the log reductions (WLR) was calculated. Populations receiving drinking water produced with higher total log reduction was associated with a lower relative number of AGI calls. In overall, AGI calls decreased by 4% (OR = 0.96, CI: 0.96–0.97) for each unit increase in the WLR. The findings apply to both groundwater and surface water study sites, but are particularly evident among surface water sites during seasons when viruses are the main cause of AGI. This study proposes that the endemic level of gastroenteritis can indeed be reduced with more advanced treatment processes at many municipal drinking water treatment plants. (it is to be expected that the water supplies always met the regulatory standards although this is not specifically stated in the abstract)

Development and validation of a method for the analysis of more than 500 pesticides and drugs in water. (Posted 20/10/2016)
A novel, fully automated contaminant screening method based on an integrated sample preconcentration and liquid chromatography coupled to high resolution mass spectrometry (SPE-UHPLC-HRMS) has been developed. The method enables the simultaneous semi quantitative analysis of 539 compounds (pesticides and drug residues), in 36 min with only 5 mL of water. Method validation was achieved through studies of repeatability, selectivity, linearity and matrix effect. Application to 20 tap water samples collected in and around Paris showed the presence of 34 different compounds all with concentrations below the European Union limit for drinking water of 0.1 μg/L,. Pesticides and transformation products frequently found in water resources such as atrazine and its metabolites, hexazinone, oxadixyl, propazine and simazine were detected. Drug residues such as valsartan and carbamazepine, usually not monitored, were also found.

Pollutants from the EU Watch List: a review of their occurrence and water-treatment options (Posted 20/10/2016)
Micropollutants are found in aquatic environments all over the world and can have negative effects on plants, animals and humans. The EU recently adopted a ‘watch list’ of potential priority substances, including pesticides, pharmaceuticals and personal care products, that need to be monitored to determine their environmental risk.(list.) A new study reviews data on their worldwide occurrence and options for their removal from wastewater, and from surface and groundwater used to produce drinking water.

Besides the substances previously recommended to be included by the Directive 39/2013/EU, namely two pharmaceuticals (diclofenac and the synthetic hormone 17-alpha-ethinylestradiol (EE2)) and a natural hormone (17-beta-estradiol (E2)), the first watch list of 10 substances/groups of substances also refers three macrolide antibiotics (azithromycin, clarithromycin and erythromycin), other natural hormone (estrone (E1)), some pesticides (methiocarb, oxadiazon, imidacloprid, thiacloprid, thiamethoxam, clothianidin, acetamiprid and triallate), a UV filter (2-ethylhexyl-4-methoxycinnamate) and an antioxidant (2,6-di-tert-butyl-4-methylphenol) commonly used as food additive. Since little is known about the removal of most of the substances included in the, particularly regarding realistic concentrations in aqueous environmental samples, this review aims to:
  1. overview the European policy in the water field;
  2. briefly describe the most commonly used conventional and advanced treatment processes to remove micropollutants;
  3. summarize the relevant data published in the last decade, regarding occurrence and removal in aqueous matrices of the 10 substances/groups of substances that were recently included in the first watch list ; and
  4. highlight the lack of reports concerning some substances of the watch list, the study of un-spiked aquatic matrices and the assessment of transformation by-products.

Global resilience analysis of water distribution systems (Posted 20/10/2016)
UK workers have developed a method to measure water systems' resilience to various failure modes. The method identifies the range of failure impacts, reveals critical scenarios and shows that increased resilience to one failure mode may decrease resilience to another. Increasing capacity may not always improve resilience and may delay system recovery. The same degree of failure can result in very different levels of failure impacts.

Treatment of groundwater containing Mn(II), Fe(II), As(III) and Sb(III) by bioaugmented quartz-sand filters (Posted 01/10/2016)
High concentrations of iron (Fe(II)) and manganese (Mn(II)) often occur simultaneously in groundwater. Previously, Chinese workers demonstrated that Fe(II) and Mn(II) could be oxidized to biogenic Fe-Mn oxides (BFMO) via aeration and microbial oxidation, and the formed BFMO could further oxidize and adsorb other pollutants (e.g., arsenic (As(III)) and antimony (Sb(III)). These workers have now shown in the laboratory that augmentation of quartz-sand filter columns with a Mn-oxidizing bacterium (Pseudomonas sp. QJX-1) accelerated the formation of Fe-Mn oxides, resulting in an increase in As and Sb removal. Bioaugmentation intensified microbial degradation/utilization for the direct removal of pollutants and increased the formation of Fe-Mn oxides for the indirect removal of pollutants. They say that their study provides an alternative method for the treatment of groundwater containing high Fe(II), Mn(II) and As/Sb.

Cryptosporidium reclassification – able to complete lifecycle without a host (Posted 29/09/2016)
Parasites of the genus Cryptosporidium are a major cause of diarrhoea and ill-health in humans and animals and are frequent causes of waterborne outbreaks. Until recently, it was thought that Cryptosporidium was an obligate intracellular parasite that only replicated within a suitable host, and that faecally shed oocysts could survive in the environment but could not multiply. In light of extensive biological and molecular data, including the ability of Cryptosporidium to complete its life cycle in the absence of a host and the production of novel extracellular stages, Cryptosporidium has been formally transferred from the Coccidia, to a new subclass, Cryptogregaria, with gregarine parasites. In this review, we discuss the close relationship between Cryptosporidium and gregarines and discuss the implications for the water industry.

Phage surrogate for adenovirus in disinfection studies. (Posted 22/09/2016)
Elucidating mechanisms by which pathogenic waterborne viruses become inactivated by drinking water disinfectants would facilitate the development of sensors to detect infectious viruses and novel disinfection strategies to provide safe water. Using bacteriophage viruses as surrogates for human pathogenic viruses could assist in elucidating these mechanisms; however, an appropriate viral surrogate for human adenovirus (HAdV), a medium-sized virus with a double-stranded DNA genome, needs to be identified. Bacteriophage PR772 has many similarities in structure and replication to HAdV. The inactivation of PR772 and HAdV by free chlorine had similar kinetics that could be represented with a model previously developed for HAdV type 2 (HAdV-2). US workers developed and tested a quantitative assay to analyze several steps in the PR772 replication cycle to determine if both viruses being inactivated at similar rates resulted from similar replication cycle events being inhibited. Like HAdV-2, we observed that PR772 inactivated by free chlorine still attached to host cells, but viral DNA synthesis and early and late gene transcription were inhibited. Consequently, free chlorine exposure inhibited a replication cycle event that was post-binding but took place prior to early gene synthesis for both PR772 and HAdV-2.

THM and birth weight (Posted 22/09/2016)
Evidence for a relationship between trihalomethane (THM) or haloacetic acid (HAA) exposure and adverse fetal growth is inconsistent. Disinfection by-products exist as complex mixtures in water supplies, but THMs and HAAs have typically been examined separately. A multi-ethnic cohort study in Bradford involving up to 7,438 singleton term babies investigated joint exposure at the individual level to THMs and HAAs in relation to birth weight. Pregnant women reported their water consumption and activities via questionnaire.

Among Pakistani-origin infants, mean birth weight was significantly lower in association with the highest versus lowest tertiles of integrated THM uptake but there were no associations among white British infants. Neither ingestion of HAAs alone or jointly with THMs was associated with birth weight.

Norovirus outbreak associated with bottled water. (Posted 22/09/2016)
Media reports suggest that in April 2016 over 4000 persons in Spain were infected with norovirus after drinking bottled water supplied from a bottling plant in Andorra. Norovirus genotypes 1 and 2 were reportedly found in the aquifer. It is suggested that this is the first outbreak associated with bottled water. There are claims that faecal indicator bacteria were not detected. At present no published results of epidemiological investigations have been seen.

Prosecution over Lead in Flint Michigan water (Posted 22/09/2016)
Following an investigation by the Michigan Attorney General into the events which resulted in exposure of residents of the town of Flint to high levels of lead in their drinking water over a period of 17 months, criminal charges have been laid against three people and a civil lawsuit have been brought against two engineering companies. The elevated lead levels were caused by failure to implement control measures to prevent corrosion of lead service pipes when the water source was changed in early 2014.

Two supervisors from the Michigan Department of Environmental Quality were charged on 20 April over their role in the decision not to implement corrosion control, and in relation to purposefully misleading the US Environmental Protection Agency into believing that a corrosion control system was being used for the Flint water supply, when in fact no such control existed. One supervisor was also charged over improperly manipulating the collection of water samples and removing test results from samples to be included in federal reports. An administrator at the Flint water treatment plant was charged with tampering with evidence by falsifying reports to state environmental officials, and wilful neglect of duty. (legal charges) This emphasises the need for regulators to be constantly vigilant.

USEPA Health Advisories on per- and poly- fluoroalkyl substances (Posted 22/09/2016)
The USEPA has issued updated health advisories for perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) following an assessment of the latest peer-reviewed scientific evidence on the health risks of these chemicals. Both substances are members of a large group of man-made chemicals known as per- and poly-fluoroalkyl substances (PFASs) which were widely used in the manufacture of consumer and industrial products from the 1950s until the early 2000s when concerns over possible health and environmental effects resulted in progressive restrictions on use. The Health Advisory levels of 70 parts per trillion (0.070 μg/L) for both chemicals (alone or combined) are not enforceable regulatory limits, but are expected to guide public water suppliers and state agencies responsible for drinking water safety in their efforts to assess and manage potential health risks.

Recent DWI guidance on the Water Supply Regulations and on UV disinfection (Posted 20/09/2016)
DWI has recently issued Guidance on implementing the Water Supply (Water Quality) Regulations in England and Wales and Updated guidance on the use of ultraviolet (UV) irradiation for the disinfection of public water supplies.

Manganese and attention deficit (Posted 14/09/2016)
Studies of children and adolescents have associated excess manganese in the diet with attention deficits, but confounding factors in those studies have made it impossible to show a cause and effect relationship. Attention deficit hyperactivity disorder (ADHD) is the most prevalent neurobehavioral disorder in children, but its cause remains unclear and probably involves many different factors.

A new study, published in Environmental Health Perspectives, is the first study to establish a causal link between exposure to elevated manganese in the diet and attentional dysfunction in an animal model.

Microbial source tracking using PhyloChip (Posted 14/09/2016)
Workers have developed a molecular source tracking test using the PhyloChip microarray (PhyloChip details) and machine-learning that detects and distinguishes fecal bacteria from humans, birds, ruminants, horses, pigs and dogs with a single test. The multiplexed assay targets 9001 different 25-mer fragments of 16S rRNA genes that are common to the bacterial community of each source type. Both random forests and SourceTracker (details)were tested as discrimination tools, with SourceTracker classification producing superior specificity and sensitivity for all source types. Validation with 12 different mammalian sources in mixtures found 100% correct identification of the dominant source and 84–100% specificity. Field test results indicate that machine-learning classification of PhyloChip microarray data can outperform conventional single marker tests that are used to assess health risks, and is an effective tool for distinguishing numerous fecal and environmental sources of pathogen indicators.

Norovirus cultured at last! (Posted 14/09/2016)
Human noroviruses -- the leading viral cause of acute diarrhea around the world -- have been difficult to study because scientists had not found a way to grow them in the lab. Now, more than 40 years after Dr. Albert Kapikian identified human noroviruses as a cause of severe diarrhea, scientists at Baylor College of Medicine have, for the first time, succeeded at growing noroviruses in laboratory cultures of human intestinal epithelial cells.

DBP reduction using novel filter materials (Posted 11/09/2016)
The removal of natural organic matter (NOM) from source water may provide a more sustainable solution to disinfection by-products (DBP). A recent study focused on the removal of NOM by novel filters, which could be retrospectively fitted to any conventional water treatment facility. The filters comprised stratified layers of a variety of media, including sand, Bayer residue, granular activated carbon (GAC), and pyritic fill. The filters were operated under two loading regimes, continuous and intermittent, at loading rates similar to recognised design standards. The most successful filter design comprised stratified layers of sand, GAC, and pyritic fill. Over the duration of a 240 day study, these filters obtained average dissolved organic carbon removal rates of 40%, and achieved average specific ultra-violet absorbance reductions from 2.9 to 2.4 L mg−1 m−1. The study demonstrates that these novel filters may be used to reduce NOM levels, thus reducing the potential for DBP formation. Such designs can incorporate the use of waste media, making the overall design more sustainable and robust.

DBPs and heart defects in babies. (Posted 25/08/2016)
A study in Massachusetts examined nine cardiovascular defects in babies in relation to categorical DBP exposures including bromoform, chloroform, dibromochloromethane (DBCM), bromodichloromethane (BDCM), monobromoacetic acid (MBAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and summary DBP measures (HAA5, THMBr, THM4, and DBP9). A number of associations were detected.

E coli can survive but not regrow in distribution. (Posted 25/08/2016)
A recent study investigated the fate of E. coli in drinking water, specifically addressing survival, biofilm formation under shear stress, and regrowth in a series of laboratory-controlled experiments. It showed the extended persistence of three E. coli strains (two enteric isolates and one soil isolate) in sterile and nonsterile drinking water microcosms at 8 and 17°C, with T90 (time taken for a reduction in cell number of 1 log10 unit) values ranging from 17.4 ± 1.8 to 149 ± 67.7 days. Furthermore, each strain was capable of attaching to a surface and replicating to form biofilm in the presence of nutrients under a range of shear stress values (0.6, 2.0, and 4.4 dynes [dyn] cm-2 BioFlux system; Fluxion); however, cell numbers did not increase when drinking water flowed over the biofilm (P > 0.05 by t test). Finally, E. coli regrowth within drinking water microcosms containing polyethylene PE-100 pipe wall material was not observed in the biofilm or water phase using a combination of culturing and Q-PCR methods for E. coli. The work concludes that when E. coli enters drinking water it has the potential to survive and attach to surfaces but that regrowth within drinking water or biofilm is unlikely.

Failure prediction for cast iron pipes. (Posted 23/06/2016)
An Australian, UK and USA consortium has carried out a 5 year project on Advanced Condition Assessment and Pipe Failure Prediction. The project addressed four questions - How, when, and where will pipes fail within the network?; How do we assess the condition of the pipe cost effectively?;. How do we calculate pipe deterioration rates accurately with respect to the pipe environment?;. How do we assess the time-dependant probability of failure along the pipeline?The key findings of the project have been summarised in an article in Advances in Water Research.
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Graphene oxide and sunlight for water purification (Posted 25/08/2016)
A team of engineers at Washington University in St. Louis has found a way to use graphene oxide sheets to transform dirty water into drinking water. The new approach combines bacteria-produced cellulose and graphene oxide to form a bi-layered structure with light-absorbing graphene oxide filled nanocellulose at the top and pristine nanocellulose at the bottom. Light radiates on top of the biofoam and converts into heat because of the graphene oxide but the heat dissipation to the bulk water underneath is minimized by the pristine nanocellulose layer which acts as a sponge, drawing water up to the graphene oxide where rapid evaporation occurs. The resulting fresh water can easily be collected from the top of the sheet.

The team hopes that for countries where there is ample sunlight, such as India, it will be possible to take some dirty water, evaporate it using the biofoam material, and collect fresh water.

Manganese in Drinking Water and Cognitive Abilities and Behavior at 10 Years of Age. (Posted 09/08/2016)
A recent cohort study involving Indian children investigated the relation between manganese in water (W-Mn) and the development of cognitive abilities and behaviour over the first 10 years of life. The study concludes that elevated prenatal W-Mn exposure was positively associated with cognitive function in girls, while boys appeared unaffected. However, early-life W-Mn exposure appeared to adversely affect children’s behavior.

Relationships among fecal indicator bacteria, microbial source tracking markers, and associated waterborne pathogen occurrence. (Posted 09/08/2016)
A US group have carried out a study to predict occurrence of waterborne pathogens in water and streambed sediments using a simple statistical model that includes traditionally measured faecal indicator bacteria, environmental parameters and source allocation, using microbial source tracking markers as predictor variables. They measured Campylobacter, Serratia, and Salmonella numbers in waterand sediments and the virulence gene that carries Shiga toxin, stx2. Pathogens were detected in water more often than in underlying sediments. Relationships between pathogens and indicator variables were generally inconsistent and no single indicator adequately described occurrence of all pathogens.

Novel membrane for lead removal (Posted 09/08/2016)
Workers in Singapore developed a novel zirconium phosphate modified polyvinyl alcohol (PVA)-PVDF membrane for removal of lead from water. The maximum adsorption capacity was 121.2 mg-Pb/g at pH 5.5, much higher than other reported adsorptive membranes. The membrane exhibited a higher selectivity for lead over zinc with a relative selectivity coefficient (Pb2+/Zn2+) of 9.92. The filtration study showed that the membrane with an area of 12.56 cm2 could treat 13.9 L (equivalent to 73,000 bed volumes) of lead containing wastewater with an influent concentration of 224.5 μ g/L to meet the maximum contaminant level of 15 μ g/L. The membrane also performed well with lead-spiked reservoir water and had a good reusability in its applications.

Drinking water contaminants from epoxy resin-coated pipes (Posted09/08/2016)
In this study 6 locations with different age epoxy linings of drinking water pipes done using two distinct technologies were studied. While bisphenol F, 4-n-nonylphenol, and 4-t-octylphenol were rarely found and in trace concentrations, BPA was detected in majority of samples. Pipes lined with the older technology (LSE) leached more BPA than those with more recent technology (DonPro): maxima in cold water were 0.25 μg/L and 10 ng/L, respectively. Incubation of water in pipes 8–10 h prior to sampling increased BPA concentration in cold water 1.1–43-fold. Hot water temperature caused even more BPA leaching - at maximum 23.5 μg/L. The influence of ageing of epoxy lining on BPA leaching on could be shown in case of LSE technology: locations with 8–9 years old lining leached 4–20-fold more BPA compared to a location with 2-year-old lining. Analysis of metals showed that epoxy lining can reduce especially iron concentration in water. No significant burden to water could be shown by the analyzed 72 volatile organic compounds, including epichlorhydrin, precursor used in epoxy resin. Estrogenicity was detected in water samples with the highest BPA loads. Comparable responses of two yeast bioreporters (estrogen receptor α and BPA-targeted) indicated that bisphenol-like compounds were the main cause of estrogenicity. Compared to the estimated average daily BPA exposure, additional BPA load via cold drinking water in the studied locations was low, maximum 8.7%. The authors suggest that hot water should also be considered as exposure source due to higher BPA concentrations. Epoxy lined locations should be monitored in future in order to evaluate ageing process and control increasing leaching of potentially harmful chemicals.

Protecting Surface Water for Health (Posted 03/08/2016)
WHO has just published a very comprehensive book which provides a structured approach to the assessment and management of drinking-water quality related risks in surface-water catchments. The publication will support the development and application of water safety planning where source-water protection is a key element in the provision of safe drinking-water. This book is a valuable adjunct to the already copious information on the WHO Water Supply Portal.

Quantitative Microbiological Risk Assessment (Posted 03/08/2016)
WHO has recently published a book which for the first time synthesizes the current knowledge on QMRA to facilitate its application in the practice of water supply, water reuse and water recreation to support the management of risks associated with faecal pathogens in the waterrelated context. A four-step QMRA framework harmonized across the water supply, reuse and recreation contexts is presented, and the value of QMRA for water safety management is described. Guidance is provided to support the successful implementation of QMRA. Key aspects include: the role of interaction between risk managers and risk assessors; interpretation of scientific data including uncertainty; and interpretation of quantitative results. Many examples including six full case studies are described.


Climate change implications for UK water supplies. (Posted 28/07/2016)
The independent Committee on Climate Change has produced a very comprehensive report on the future impact of climate change for the United Kingdom based on the inputs of a wide range of experts.

The report states that “climate change is projected to reduce the amount of water in the environment that can be sustainably withdrawn whilst increasing the demand for irrigation during the driest months. At the same time the growing population will create additional demands on already stretched resources in some parts of the country. Even low population growth and modest climate change scenarios suggest severe water supply deficits, and with high population growth and more severe climate change these deficits deepen and by the 2050s extend across the UK. Whilst there is significant action already underway, there is an urgent need for longer-term water resource planning to assess the scale of risks and consider strategic options, more co-ordinated action to ensure resilient supplies especially in times of drought, and further steps to achieve the ambitious reductions in water demand and leakage that are likely to be required. Otherwise there could be increasingly difficult trade-offs between the needs of industry, farming and the public water supply, and the ecological status of rivers, lakes,estuaries, and groundwater.

The recent vote in favour of leaving the European Union does not change the overall findings of this risk assessment. However, the magnitude of individual climate change risks and opportunities could be affected if legislation, policy and funding derived from the EU, relevant to climate change adaptation, are changed. Important areas include the Common Agricultural and Fisheries Policies, the Water Framework, Bathing Water, Birds, Habitats, Floods, Urban Waste Water Treatment and Solvency II Directives, and the European Structural Investment Fund. Compensatory UK measures may be stronger or weaker than their EU equivalents.”

Microbes can produce halogenated organic pollutants (Posted 21/07/2016)
For a long time it has been assumed that halogenated organic compounds are only produced and released by human activity. However, in recent years, over 5,000 naturally-occurring organohalogen compounds have been identified, and evidence suggests that the cycling of halogens e.g. chlorine, bromine in soils is largely driven by microbial processes. Workers in Germany studied soil in a pristine forest by analysing the whole gene pool found in the earth, the metagenome. They did not isolate individual organisms but identified all of the great diversity of genes from bacteria, fungi and archaea coding for halogenating and dehalogenating enzymes.

Water Quality interventions in low-income countries can have adverse effects. (Posted 21/07/2016)
A recent paper compares results of blind and open trials of water quality interventions. Although open trials may be affected by reporting bias, evidence suggests that despite instructions to the contrary, placebos may encourage control group participants in blinded trials to cease practicing traditional water treatment practices such as boiling in the mistaken belief that they are protected by an active intervention. The paper references an interesting study (link) in which a sham filter shown to have no effect in the lab actually removed 90% of fecal indicator bacteria in the field (probably due to accumulated biofilm).

Pinpointing leaks by noise loggers (Posted 30/06/2016)
A paper from Concordia University,Montreal notes that noise loggers have usually been used only for localizing leaks while other tools were used for locating and pinpointing. It describes the development of regression and artificial neural network (ANN) models to localize and locate leaks in water pipelines using noise loggers. Several lab experiments were conducted to simulate actual leaks in a sample ductile iron pipeline distribution network with valves. The noise loggers were used to detect these leaks and record their noise readings. The recorded noise readings were then used as input data for the developed models. The ANN models outperformed regression models during testing. Moreover, ANN models were successfully validated using an actual case study.

Water treatment processes and endemic gastrointestinal illness. (Posted 30/06/2016)
Over a seven year period a Swedish study has examined all telephone calls from 20 cities to the Swedish National Health Guide relating to acute gastrointestinal illness (AGI) and related each one to the treatment applied to the person's drinking water. Using the theoretical log reduction for various infectious agents by each treatment stage they calculated a weighted mean value (WLR) for the treatment applied to each water supply. The WLR in the plants varied between 0.0 and 6.4 units

Populations receiving drinking water produced with higher total log reduction was associated with a lower relative number of AGI calls. In overall, AGI calls decreased by 4% (OR = 0.96, CI: 0.96–0.97) for each unit increase in the WLR. The findings apply to both groundwater and surface water study sites, but are particularly evident among surface water sites during seasons when viruses are the main cause of AGI. This study proposes that the endemic level of gastroenteritis can indeed be reduced with more advanced treatment processes at many municipal drinking water treatment plants.

Perfluorinated chemicals in drinking water (Posted 30/06/2016)
The USEPA has issued advisory notices in respect of 2 perfluorinated chemicals in water, namely perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). A maximum value of 0.07 micrograms per litre is recommended for each substance. (DWI Report) (DWI Guidance)

Disinfection of Escherichia coli and Pseudomonas aeruginosa by copper in water (Posted 21/06/2016)
Storage in copper vessels has been shown to reduce microbes, but inactivation kinetics of enteric bacteria in water by copper alone needs to be understood. A recent paper characterized inactivation kinetics of Escherichia coli and Pseudomonas aeruginosa by dissolved ionic copper in water. Reductions of E. coli and P. aeruginosa increase with increasing dose. At 0.3 mg/L, there was a 2.5 log10 reduction of E. coli within 6 hours. At 1 and 3 mg/L, the detection limit was reached between 3 and 6 hours; maximum reduction measured was 8.5 log10. For P. aeruginosa, at 6 hours there was 1 log10 reduction at 0.3 mg/L, 3.0 log10 at 1 mg/L, and 3.6 log10 at 3 mg/L. There was no significant decline in copper concentration. Copper inactivates bacteria under controlled conditions at doses between 0.3 and 1 mg/L. E. coli was inactivated more rapidly than P. aeruginosa. Copper at 1 mg/L can achieve 99.9% inactivation of P. aeruginosa and 99.9999997% inactivation of E. coli over 6 hours, making it a candidate treatment for stored household water.

Effects of plumbing systems on DBPs (Posted 21/06/2016)
Trihalomethanes (THMs) in plumbing pipes and hot water tanks were observed to be 1.1–2.4 and 1.6–3.0 times, respectively, to THMs in the supply system, while haloacetic acids (HAAs) were 0.9–1.8 and 1.2–1.9 times, respectively, to HAAs in supply. (This supports the regulation of drinking water quality being applied at the point of use).

Removal of septic and musty odours. (Posted 21/06/2016)
Chinese workers studied the removal of musty and septic odours in a Water Treatment Plant equipped with coagulation, sedimentation, ozonation, biological activated carbon (BAC) filtration, sand filtration, and chlorination in succession. The source water was constantly associated with septic and musty odors. Flavor profile analysis (FPA) results showed that Geosmin and 2-MIB, with an average OAV of 4.54 and 1.38, respectively, were the major odorants for musty odour, while bis(2-chloroisopropyl) ether, DEDS (di-ethyl disulphide) and DMDS (di-methyl disulphide) with an average OAV ( odour activity value)of 2.35, 1.65 and 0.78, respectively, might be responsible for the septic odour. While the musty odour could be removed effectively through the combination of ozonation and BAC, the septic odour and associated odourants required further treatment with sand filtration and chlorination for complete removal. It is clear that the advanced treatment process was effective for the treatment of source water containing complicated odourants. It should be noted that the sedimentation process needs careful management because release of odourants may occur during the treatment. The result of this study will be helpful for the mitigation of odors in WTP using source waters suffering from complicated odor problems.

Impact of improving treatment on distribution system water quality (Posted 13/06/2016)
A recent 2-year study utilised four parallel pilot distribution systems (PDS) and a range of simple tools to assess the impact improving treatment had on the water quality within the distribution system. Particle counting was more effective than turbidity to assess the impact of increasing treatment on sediment load entering the PDS while UV254 was as informative as dissolved organic carbon to assess organic load but has the additional potential benefit of on-line measurement. However, variability in water quality entering the PDS was often greater than measurable changes occurring within the PDS. It was critical to compare water quality entering the distribution system with the water quality at a defined point within the distribution system (at known hydraulic detention time) to enable effective assessment of water quality changes. Therefore, effective use of these simple tools requires monitoring of both inlet and distribution system locations, together with long term trending to monitor and compare changes within the system.

EU call for open access to all scientific papers (Posted 13/06/2016)
E.U. member states agreed on an ambitious new open-access (OA) target under which all scientific papers should be freely available by 2020, but some observers are warning that the goal will be difficult to achieve. There are as yet no clear suggestions as to how this might be achieved but one suugestion is that papers should be made available in an institutional repository immediately on acceeptance for publication The OA goal is part of a broader set of recommendations in support of open science, a concept that also includes improved storage of and access to research data.

Government loses track of its own research. (Posted 13/06/2016)
A recent independent report into Government research spending has concluded that while approximately £5bn is spent annually on government research, there is no reliable breakdown of what that money is spent on or what happens to the studies. Many departments and arm’s length bodies do not collect information centrally about what research they have commissioned, and teams within departments and arm’s length bodies can conduct or commission their own research without the rest of the organisation knowing about it. There is however a publicly accessible database of all Defra commisssioned research which includes most if not all water supply related research.

“Deep water desalination” (Posted 06/06/2016)
A scheme described as deep water desalination is proposed for Monterey Bay in California USA. The scheme will take cold water from well below the ocean surface and use it for cooling a computer facility before treating it by desalination. The proposed output is expressed in somewhat curious units as 25,000 acre feet per year. The water will be abstracted at a depth of 100 feet (sic) on the slope of a deep underwater canyon and the rejected brine discharged at a depth of 35 meters (sic) much further out from shore than the intake. Despite the idiosyncratic and arbitrary use of units the concept of using the water for more than one purpose is interesting.

The role of backwash in start-up of full-scale drinking water biofilters (Posted 06/06/2016)
The purpose of backwashing during the start-up period of rapid biofilters at drinking water treatment plants differs significantly from the purpose of backwashing during normal operation. During start-up, finished water quality is secondary, detachment of microorganisms must be minimized, dust present in the original filter media must be removed and inherent inoculation of the biofilter with water used for backwashing must be considered. Investigations over a 9-week start-up period at a full-scale waterworks showed a strong correlation between suspended solids and turbidity, and that fine particles present in the original filter media were removed over a period of several weeks. In addition, after an initial period in which iron accumulated on the filter was not removed by backwash, iron was removed with 80% efficiency. Backwashing had 0% efficiency in removing manganese from the filter media. Practical conclusions include that shortened backwash procedures during start-up may be preferable, turbidity may be used as a surrogate for suspended solids in backwash effluent, filter media may be pre-treated by exaggerated backwashing to remove fine particles before start-up, and that a reasonable backwash procedure for future operation of the filter may be defined early in the start-up period.

Rapid detection of E.coli in contaminated water (Posted 06/06/2016)
Canaadian workers have developed a hydrogel-based rapid detection method for E.coli in comtaminated waters. Using an integrated plunger-tube assembly containing the hydrogel matrix the system allows efficient, field deployable, rapid testing of water samples by simultaneously pre-concentrating and detecting E. coli within one integrated unit. The workers were able to detect E. coli concentrations of 4 × 106 CFU mL−1 to 4 × 105 CFU mL−1 within 5 min and 4 × 104 CFU mL−1 to 400 CFU mL−1 within 60 min.

Cryptosporidium and stunted growth (Posted 30/05/2016)
A Bangladeshi study followed 392 babies for the first two years of life. Malnutrition was common in the children and 56% were significantly stunted by age 2. Children with Cryptosporidium spp. infection had a greater than 2-fold increased risk of severe stunting at age two compared to uninfected children (odds ratio 2.69, 95% CI 1.17, 6.15, p = 0.019) independent of sex, income, maternal body-mass index, maternal education and weight for age adjusted z (WAZ) score at birth.. Cryptosporidium infection is common (77%) in this cohort of slum-dwelling Bangladeshi children, and two thirds of the cases of infection detected were non-diarrhoeal. Both non-diarrheal and diarrheal infections are significantly associated with impairment of a child’s growth at 2 years of age. (the study does not show that there are any implications for otherwise well-nourished children).

Nanotechnology for arsenic removal (Postred 25/05/2016)
A team of Indian workers has developed a new treatment based on nanotechnology which purifies water, removes arsenic, and does this at a price affordable for the poorest communities.

The team has manipulated silver nanoparticles, impregnated within a protective ‘cage’ built out of nanomaterials like aluminium and the chitin from crustacean shells. The resulting reaction breaks down the halocarbons of pesticides and other microbial contaminants into harmless metal halides and amorphous carbon. The technology requires no power and has no disposable parts. Field trials are under way. Although it can deliver safe water for less than $0.0007/litre it doesn't offer the prospect of large profits to investors when the main beneficiaries are the poorest communities.

Future impact of water shortage (Posted 25/05/2016)
The World Bank warns that by 2050, growing demand for cities and for agriculture would put water in short supply in regions where it is now plentiful – and worsen shortages across a vast swathe of Africa and Asia, spurring conflict and migration. The biggest economic hits due to water deficits were expected to occur in the Middle East, north Africa, central Asia, and parts of south Asia, the report found. There would be virtually no impact on the economies of North America and western Europe but globally GDP could fall by around 6%.

New UK Clean Water Research Consortium (Posted 17/05/2016)
The recently established EPSRC Grand Challenge research centre TWENTY65 is tackling the challenge of sustainable clean water over the next 50 years through research and collaboration across the water industry. The consortium includes the Universities of Sheffield, Exeter, Imperial College, Manchester, Newcastle, and Reading,  Key representatives from the UK Water Partnership have been appointed to the governance boards.

Lead in drinking water in large buildings (Posted 17/05/2016)
Lead results from 78,971 water samples collected in four Canadian provinces from elementary schools, daycares, and other large buildings showed maximum concentrations reached 13,200 and 3890 μg/L following long and short stagnation periods respectively. High lead levels were persistent in some large buildings, reflected by high median values considering all taps, or specific to a few taps in the building. Simulations showed that, for most buildings, exposure to lead at the tap does not increase children's blood lead levels. However, buildings or taps with extreme concentrations represent a significant health risk to young children and could lead to acute exposure. For a few taps, the total daily lead intake reached the former World Health Organization (WHO) tolerable level for adults, suggesting potential health risks.

Destratification of raw water reservoirs (Posted 16/05/2016)
Southern Water has joined a growing number of water suppliers installing the ResMix source management technology for tackling stratification in raw water reservoirs. The system works using an impellor to drive surface water into the reservoir depths which promotes vertical circulation. (This note is not an endorsement by FWR of the commercial technology)

Taste of RO water. (Posted 15/04/2016)
European workers examined differences in taste between various remineralised drinking waters. Comparing tap waters and RO waters with and without remineralisation. Total dissolved solids (TDS) was a major determinant of the taste perception of water. In general, lowering mineral content in drinking water in the range examined (from <5 to 440 mg/L) shifted the sensory perception of water from fresh towards bitter, dry, and rough sensations. In addition, perceived freshness of the waters correlated positively with calcium concentration. The greatest fresh taste was found for water with a TDS between 190 and 350 mg/L. Remineralisation of water after reverse osmosis can improve drinking quality significantly.