Water age in drinking water systems is often used as a proxy for water quality but is rarely used as a direct input in assessing microbial risk. This study directly linked water ages in a premise ...plumbing system to concentrations of Legionella pneumophila via a growth model. In turn, the L. pneumophila concentrations were used for a quantitative microbial risk assessment to calculate the associated probabilities of infection (P inf) and clinically severe illness (P csi) due to showering. Risk reductions achieved by purging devices, which reduce water age, were also quantified. The median annual P inf exceeded the commonly used 1 in 10,000 (10–4) risk benchmark in all scenarios, but the median annual P csi was always 1–3 orders of magnitude below 10–4. The median annual P csi was lower in homes with two occupants (4.7 × 10–7) than with one occupant (7.5 × 10–7) due to more frequent use of water fixtures, which reduced water ages. The median annual P csi for homes with one occupant was reduced by 39–43% with scheduled purging 1–2 times per day. Smart purging devices, which purge only after a certain period of nonuse, maintained these lower annual P csi values while reducing additional water consumption by 45–62%.
Next-generation sequencing has revealed that less than 2% of transcribed genes are translated into proteins, with a large portion transcribed into noncoding RNAs (ncRNAs). Among these, long noncoding ...RNAs (lncRNAs) represent the largest group and are pervasively transcribed throughout the genome. Dysfunctions in lncRNAs have been found in various diseases, highlighting their potential as therapeutic, diagnostic, and prognostic targets. However, challenges, such as unknown molecular mechanisms and nonspecific immune responses, and issues of drug specificity and delivery present obstacles in translating lncRNAs into clinical applications. In this review, we summarize recent publications that have explored lncRNA functions in human diseases. We also discuss challenges and future directions for developing lncRNA treatments, aiming to bridge the gap between functional studies and clinical potential and inspire further exploration in the field.
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The discovery of functional lncRNAs and their mechanisms in physiology and disease has been facilitated by next-generation sequencing and high-throughput screening. While clinical potential is promising, challenges remain in diagnosis, drug delivery, and immune response. Identifying functional mechanisms and solving clinical challenges are key to advancing lncRNA-based tools.
Interest in ecosystem services has grown tremendously among a wide range of sectors, including government agencies, NGO’s and the business community. Ecosystem services entailing freshwater (e.g. ...flood control, the provision of hydropower, and water supply), as well as carbon storage and sequestration, have received the greatest attention in both scientific and on-the-ground applications. Given the newness of the field and the variety of tools for predicting water-based services, it is difficult to know which tools to use for different questions. There are two types of freshwater-related tools – traditional hydrologic tools and newer ecosystem services tools. Here we review two of the most prominent tools of each type and their possible applications. In particular, we compare the data requirements, ease of use, questions addressed, and interpretability of results among the models. We discuss the strengths, challenges and most appropriate applications of the different models. Traditional hydrological tools provide more detail whereas ecosystem services tools tend to be more accessible to non-experts and can provide a good general picture of these ecosystem services. We also suggest gaps in the modeling toolbox that would provide the greatest advances by improving existing tools.
► We compared examples of two classes of models for freshwater ecosystem services. ► Traditional hydrological models include SWAT and VIC. ► Ecosystem Services specific models include InVEST and ARIES. ► We compared key inputs, outputs, services modeled, usability, and interpretability. ► Hydrological tools give more detail but ecosystem services tools are more accessible.
Residential buildings provide unique conditions for opportunistic premise plumbing pathogen (OPPP) exposure via aerosolized water droplets produced by showerheads, faucets, and tubs. The objective of ...this review was to critically evaluate the existing literature that assessed the impact of potentially enhancing conditions to OPPP occurrence associated with residential plumbing and to point out knowledge gaps. Comprehensive studies on the topic were found to be lacking. Major knowledge gaps identified include the assessment of OPPP growth in the residential plumbing, from building entry to fixtures, and evaluation of the extent of the impact of typical residential plumbing design (e.g., trunk and branch and manifold), components (e.g., valves and fixtures), water heater types and temperature setting of operation, and common pipe materials (copper, PEX, and PVC/CPVC). In addition, impacts of the current plumbing code requirements on OPPP responses have not been assessed by any study and a lack of guidelines for OPPP risk management in residences was identified. Finally, the research required to expand knowledge on OPPP amplification in residences was discussed.
Opportunistic pathogens occurring in premise (i.e., building) plumbing systems, including strains of Legionella, Mycobacterium, Acanthamoeba, and Pseudomonas, are now frequently cited agents of ...waterborne disease outbreaks. Unlike traditional fecal pathogens, opportunistic pathogens are part of the drinking water microbial ecology and therefore require new paradigms for their control. With the onset of the “microbiome era”, notions of eradicating all microbes in drinking water have proven unrealistic, making a probiotic concept worthy of consideration. Research is needed to better understand how engineering controls may individually, or in combination, select for a desirable microbiome, and how the microbiome itself may mediate proliferation of opportunistic pathogens. Ecological interactions such as competition, antagonism, and obligate parasite-host relationships offer potential targets for probiotic control of opportunistic pathogens. A probiotic approach may be defined as intentional inoculation of beneficial microbes or choosing conditions that select for a desirable microbiome. This critical review synthesizes the state of the knowledge of the factors governing opportunistic pathogen control in premise plumbing and potential opportunities for and barriers to implementation of a probiotic approach. Future effort is recommended to demonstrate the feasibility of the probiotic concept; to develop effective, practical, and safe protocols; and to engage relevant stakeholders in evaluating options and assessing corresponding risks.
Plastic pipes have been and are being installed downstream of metal drinking water plumbing components. Prior research has suggested that such pipe configurations may induce plastic pipe degradation ...and even system failure. To explore the impact of upstream metal plumbing components on downstream plastic pipes, field- and bench-scale experiments were conducted. Six month old galvanized iron pipes (GIPs) and downstream crosslinked polyethylene (PEX) pipes were exhumed from a residential home. Calcium, iron, manganese, phosphorous, and zinc were the most abundant elements on both GIPs and PEX pipes. Black and yellow deposits were found on some of the exhumed PEX pipe inner walls, which were mainly copper, iron, and manganese oxides (CuO, Cu(OH)2, Fe2O3, FeOOH and MnO2). Follow-up bench-scale experiments revealed that metal levels in the drinking water did not always predict metal loadings on plastic pipe surfaces. The pH 4 water resulted in a greater amount of metals released into the bulk water, but the pH 7.5 water resulted in a greater amount of metals deposited on the PEX pipe surfaces. Hot water (55 °C) induced a greater amount of organics released and higher metal loadings on PEX pipe surfaces at pH 7.5. ATR-FTIR analysis showed that at 55 °C, PEX pipes connected to copper and brass components had the greatest oxidation functional group peak intensity (COOC, CO, and COC). This study highlights potential downstream plastic pipe degradation and metal deposition, which may cause plumbing problems and failures for building owners, inhabitants, and water utilities.
•PEX pipe degradation in metal-plastic hybrid plumbing networks was examined.•CuO, Cu(OH)2, FeOOH, Fe2O3, and MnO2 were found on exhumed PEX pipe surfaces.•Moderate water at 55 °C resulted the greatest metal loading on plastic surfaces.•PEX pipes exposed to hot water released more organic carbon than cold water.•PEX pipes connected to copper and brass had the greatest plastic surface oxidation.
Premise plumbing materials such as pipes, valves, fittings, and faucets are made of various materials, including plastic, stainless steel, copper, and brass/bronze. Although lead pipe has been banned ...for its use in drinking water supply by most countries in the 1980s, lead is still commonly used as an additive in many plumbing materials for its flexibility and malleability. Certified leaching tests for plumbing materials are usually conducted using relatively mild solutions over short periods which may not reveal the true risk of lead exposure when these materials are used. The objective of this study is to investigate the extents of lead release from commonly used premise plumbing materials into drinking water. The maximum lead leaching potential for pluming material was operationally determined using high strength acidic EDTA solutions (pH 4, EDTA = 100 mg/L) for a stagnation time of 3 days for a total period of up to 1 month. Lead leaching from each plumbing material was also evaluated using reconstituted tap water. Brass- and bronze-based plumbing materials were found to release dangerous levels of lead. Surface lead weight percentage obtained using SEM-EDX and lead weight percentages of the material body obtained using strong acid digestion were found to positively correlate with lead release. A re-examination of the appropriateness of current certified leaching tests and a more stringent regulation on the use of lead as an additive for plumbing materials should be considered.
•After stagnation, Pb increased in preschool sinks containing point-of-use filters.•Pb concentrations did not increase with stagnation in the laboratory filter setup.•Preschool likely had Pb plumbing ...components downstream of the point-of-use filters.•Point-of-use filters effectively removed chlorine in the preschool and the laboratory.•Bacteria concentrations significantly increased with filtration and stagnation.
A local preschool installed NSF/ANSI 42 and 53 certified point-of-use (POU) filters in its classroom sinks and drinking fountains to protect children from the possibility of elevated lead (Pb) levels in drinking water. We examined the effects of these filters during flowing water and immediately following stagnation periods on Pb, chlorine, and bacterial concentrations in the field and the laboratory. Before and after typical school stagnation periods, we collected samples from filtered classroom sinks, a filtered drinking fountain and nearby unfiltered sinks for a year. No unfiltered samples exceeded Illinois State limits of 5 µg/L for Pb in pre-K through 5th grade schools. However, following stagnation periods as short as overnight (14.5 h), over half of post-stagnation filtered samples from classroom sinks exceeded 5 µg/L while post-stagnation unfiltered samples remained below 5 µg/L. Laboratory testing showed no significant increases in Pb with stagnation, suggesting that the preschool classrooms may have had Pb-bearing plumbing downstream of the filters which released Pb into the filtered drinking water. The filters effectively removed free chlorine (99% decrease) in both the preschool and laboratory. Installing the filters had the unintended consequence of significantly increasing the bacterial concentrations (as measured by qPCR) in the preschool's drinking water and in laboratory filter effluent. Legionella pneumophila, Pseudomonas aeruginosa, and Mycobacterium spp. were not detected in pre-stagnation unfiltered and post-stagnation filtered samples. These results suggest that the installation of POU filters be considered as one component of an overall strategy to decrease Pb concentrations in school drinking water that holistically considers the premise plumbing system. A 5-minute flush significantly decreased concentrations of Pb and bacteria in filtered sinks. Replacing Pb-bearing plumbing components downstream of a POU filter may also be needed to combat Pb levels in drinking water.
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Tap water mistrust has adverse impacts on health and welfare. This study identifies, defines and motivates attention to cases of mistrust of tap water which originate between the treatment plant and ...the tap where people ultimately consume it. Between treatment and the tap, water quality contamination can be introduced within two segments of the built environment with two distinct responsible parties— community water system's distributional networks and property owner's premise plumbing. This contamination is considered secondary from a health perspective but elevates consumer concern. We use examples from Los Angeles County, an area with high resident tap water mistrust especially among disadvantaged communities, despite there being relatively few health-related water quality violations.
We triangulate evidence from primary and secondary sources to illustrate how such water quality concerns occur. We identify potential solutions to address concerns using a series of case studies of communities with high levels of tap water mistrust, a stakeholder workshop and associated working group on premise plumbing concerns, and customer concern data from the city of Los Angeles' water system. Findings suggest that there are numerous instances where the distributional network, and secondarily premise plumbing, introduce water quality contamination which contributes to tap mistrust in urban communities by making water unclean, but not necessarily unsafe per existing regulation. In cases where water systems' distributional networks have introduced water quality contamination, responses to assuage concerns have largely rested upon pressure from the press and advocates. Premise plumbing issues have been harder to address.
Our study suggests that an evidence-based path forward to comprehensively addressing these issues involves new requirements for systems to report quality contamination in distributional networks and incentives for property owners to upgrade premise plumbing. Moreover, this study reasserts that infrastructure neglect contributes to rational, but costly decision-making by disadvantaged urban communities to consume tap alternatives.
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•Contamination introduced within system distribution networks and premise plumbing contributes to tap water mistrust•Four case studies of and customer complaint data on tap mistrust from Los Angeles are analyzed•Further data release, testing by systems and incentives for landlords are required to address causes of mistrust
