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1.
Water Res ; 251: 121098, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38219686

RESUMEN

Manual flushing of building plumbing is commonly used to address water quality issues that arise from water stagnation. Autonomous flushing informed by sensors has the potential to aid in the management of building plumbing, but a number of knowledge gaps hinder its application. This study evaluates autonomous flushing of building plumbing with online sensor and actuator nodes deployed under kitchen sinks in five residential houses. Online oxidation-reduction potential (ORP) and temperature data were collected for nine weeks during the winter and summer in houses with both free chlorine and chloramine. ORP levels in houses with free chlorine residuals decreased after overnight stagnation. The overnight decrease in ORP was not observed when tap water was automatically flushed for five minutes at 6:00 h every morning. ORP levels in houses with chloramine residuals did not decrease consistently after overnight stagnation, and daily automated flushes did not have an observable effect on the ORP signals. Additional laboratory experiments were carried out to evaluate ORP signals during chlorine decay and after incremental changes in chlorine, as would be expected in building plumbing conditions. Results from the lab and field deployments suggest on-line ORP sensors may be used to detect free chlorine decay due to stagnating water, but are not as effective in detecting chloramine decay. However, field results also suggest ORP may not respond as expected on a timely manner after free chlorine or chloramine have been restored, hindering their applicability in developing control algorithms. In this paper we tested twice-daily five-minute automatic flushing and found that it counteracts water quality degradation associated with overnight stagnation in free chlorine systems. An automatic sensor-based flushing is proposed using online temperature sensor data to determine when flushing has reached water from the main. The results suggest that flushing informed by temperature sensors can reduce the flushing time by 46 % compared to the preset five-minute static flush.


Asunto(s)
Agua Potable , Ingeniería Sanitaria , Abastecimiento de Agua , Cloraminas , Cloro , Temperatura , Oxidación-Reducción
2.
Environ Pollut ; 337: 122520, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37678732

RESUMEN

Despite being corrosion-resistant, plastic potable water pipes might accumulate heavy metals on their surface if they convey metal-contaminated tap water. This study examined the influence of water pH and flow conditions on lead (Pb) release from new and biofilm-laden potable water pipes to provide insights regarding decontamination. For this purpose, biofilms were grown onto new crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper pipes for three months. Lead was then deposited onto the new and biofilm-laden pipes through 5 d exposure experiments under flow conditions. After that, lead release experiments were conducted by exposing the lead-accumulated pipes to lead-free synthetic tap water for 5 d, under both stagnant and water flow conditions. The metal accumulation study showed no significant difference in lead uptake by new pipes and their biofilm-laden counterparts under flow conditions. This could be attributed to the detachment of biofilms that have accumulated lead as water flows through the pipes. Water flow conditions significantly influenced the lead release from new and biofilm-laden water pipes. A lower water pH of 5.0 increased the release of lead from plastic pipes into the contact water, compared to pH 6.0 and 7.8. The greatest percentage of lead was released from biofilm-laden HDPE pipes (5.3%, 120 h) compared to biofilm-laden copper pipes (3.9%, 6 h) and PEX-A (3.7%, 120 h) and after exposure to lead-free synthetic tap water at pH 5.0, under stagnant conditions. On the other hand, under water flow conditions, the greatest lead release was found for new PEX-A pipes (4.4%, 120 h), new HDPE pipes (2.7%, 120 h), and biofilm-laden copper pipes (3.7%, 2 h).


Asunto(s)
Agua Potable , Ingeniería Sanitaria , Cobre/análisis , Plomo , Abastecimiento de Agua , Polietileno , Descontaminación , Biopelículas
3.
Zebrafish ; 20(3): 122-125, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37310180

RESUMEN

One of the greatest expenses in running a zebrafish laboratory is the aquatic systems used for housing. These critical pieces of equipment are essential and incorporate components undergoing constant activity in pumping water, monitoring, dosing, and filtration. The systems available on the market are robust, yet ongoing activity eventually leads to the need for repair or replacement. Moreover, some systems are no longer commercially available, impairing the ability to service this critical infrastructure. In this study, we demonstrate a do it yourself (DIY) method to re-engineer an aquatic system's pumps and plumbing, which hybridizes a system no longer commercially available with components used by active vendors. This transition from a two external pump Aquatic Habitat/Pentair design to an individual submerged pump Aquaneering-like plan saves funds by expanding infrastructure longevity. Our hybridized configuration has been in uninterrupted use for >3 years, supporting zebrafish health and high fecundity.


Asunto(s)
Ingeniería Sanitaria , Pez Cebra , Animales , Fertilidad , Laboratorios , Longevidad
4.
Water Res ; 241: 120149, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37270942

RESUMEN

Premise plumbing plays an essential role in determining the final quality of drinking water consumed by customers. However, little is known about the influences of plumbing configuration on water quality changes. This study selected parallel premise plumbing in the same building with different configurations, i.e., laboratory and toilet plumbing. Water quality deteriorations induced by premise plumbing under regular and interrupted water supply were investigated. The results showed that most of the water quality parameters did not vary under regular supply, except Zn, which was significantly increased by laboratory plumbing (78.2 to 260.7 µg/l). For the bacterial community, the Chao1 index was significantly increased by both plumbing types to a similar level (52 to 104). Laboratory plumbing significantly changed the bacterial community, but toilet plumbing did not. Remarkably, water supply interruption/restoration led to serious water quality deterioration in both plumbing types but resulted in different changes. Physiochemically, discoloration was observed only in laboratory plumbing, along with sharp increases in Mn and Zn. Microbiologically, the increase in ATP was sharper in toilet plumbing than in laboratory plumbing. Some opportunistic pathogen-containing genera, e.g., Legionella spp. and Pseudomonas spp., were present in both plumbing types but only in disturbed samples. This study highlighted the esthetic, chemical, and microbiological risks associated with premise plumbing, for which system configuration plays an important role. Attention should be given to optimizing premise plumbing design for managing building water quality.


Asunto(s)
Ingeniería Sanitaria , Calidad del Agua , Microbiología del Agua , Abastecimiento de Agua , Pseudomonas
5.
Environ Sci Technol ; 57(16): 6360-6372, 2023 04 25.
Artículo en Inglés | MEDLINE | ID: mdl-37036108

RESUMEN

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.


Asunto(s)
Agua Potable , Ingeniería Sanitaria , Abastecimiento de Agua , Vivienda , Microbiología del Agua
6.
Nat Commun ; 14(1): 358, 2023 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-36690620

RESUMEN

The 2021 volcanic eruption at La Palma, Canary Islands, was the island's most voluminous historical eruption. Little is known about this volcano's feeding system. During the eruption, seismicity was distributed in two clusters at ~10-14 km and ~33-39 km depth, separated by an aseismic zone. This gap coincides with the location of weak seismic swarms in 2017-2021 and where petrological data have implied pre-eruptive magma storage. Here we use seismological methods to understand the seismic response to magma transfer, with 8,488 hypocentral relocations resolving small-scale seismogenic structures, and 156 moment tensors identifying stress heterogeneities and principal axes flips. Results suggest a long-lasting preparatory stage with the progressive destabilisation of an intermediate, mushy reservoir, and a co-eruptive stage with seismicity controlled by the drainage and interplay of two localised reservoirs. Our study provides new insights into the plumbing system that will improve the monitoring of future eruptions in the island.


Asunto(s)
Exantema , Ingeniería Sanitaria , Humanos , España , Heterogeneidad Genética , Solución de Problemas
8.
Sensors (Basel) ; 22(13)2022 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-35808431

RESUMEN

Building Information Modeling (BIM) has been increasingly used in coordinating the different mechanical, electrical, and plumbing (MEP) services in the construction industries. As the construction industries are slowly adapting to BIM, the use of 2D software may become obsolete in the future as MEP services are technically more complicated to coordinate, due to respective services' codes of practice to follow and limit ceiling height. The 3D MEP designs are easy to visualize before installing the respective MEP services on the construction site to prevent delay in the construction process. The aid of current advanced technology has brought BIM to the next level to reduce manual work through automation. Combining both innovative technology and suitable management methods not only improves the workflow in design coordination, but also decreases conflict on the construction site and lowers labor costs. Therefore, this paper tries to explore possible advance technology in BIM and management strategies that could help MEP services to increase productivity, accuracy, and efficiency with a lower cost of finalizing the design of the building. This will assist the contractors to complete construction works before the targeted schedule and meet the client's expectations.


Asunto(s)
Industria de la Construcción , Ingeniería Sanitaria , Automatización , Humanos , Tecnología de la Información , Programas Informáticos
10.
PLoS One ; 17(2): e0263297, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35113948

RESUMEN

In Pakistan, antimicrobial resistance (AMR) is expected to greatly increase the already high mortality and morbidity rates attributed to infections, making AMR surveillance and prevention a priority in the country. The aims of the project were to characterize the prevalence of carbapenem-resistant Enterobacteriaceae (CRE) in healthcare facility sink drains in Pakistan and to characterize how physical characteristics of sinks and healthcare facility rooms were associated with CRE in those sinks. The study took place in 40 healthcare facilities in Jamshoro Pakistan. Swabs were collected from sink drains in each facility that had a sink, and structured observations of sinks and facilities were performed at each facility. Swabs were plated on CHROMagar KPC to screen for carbapenem-resistant Enterobacteriaceae, which were then isolated on Mueller-Hinton agar plates. Antibiotic susceptibility was determined using the disk diffusion method to assess resistance to carbapenems, cephalosporins, and fluoroquinolones. Thirty-seven of the healthcare facilities had at least one sink, and thirty-nine total sinks were present and sampled from those healthcare facilities. Sinks in these facilities varied in quality; at the time of sampling 68% had water available, 51% had soap/alcohol cleanser at the sink, 28% appeared clean, and 64% drained completely. Twenty-five (64%) of the sink samples grew Enterobacteriaceae on CHROMagar KPC, sixteen (41%) of which were clinically non-susceptible to ertapenem. Seven of the 39 sampled sinks (18%) produced Enterobacteriaceae that were resistant to all three antibiotic classes tested. Several facilities and sink characteristics were associated with CRE. Sinks and drains can serve as undetected reservoirs for carbapenem-resistant Enterobacteriaceae. Control and remediation of such environments will require both systemic strategies and physical improvements to clinical environments.


Asunto(s)
Enterobacteriaceae Resistentes a los Carbapenémicos/química , Infección Hospitalaria/epidemiología , Infección Hospitalaria/prevención & control , Descontaminación/métodos , Infecciones por Enterobacteriaceae/transmisión , Enterobacteriaceae/aislamiento & purificación , Desinfección de las Manos , Ingeniería Sanitaria , Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , Estudios Transversales , Difusión , Microbiología Ambiental , Instituciones de Salud , Hospitales , Humanos , Control de Infecciones , Pruebas de Sensibilidad Microbiana , Pakistán/epidemiología
11.
Bol. malariol. salud ambient ; 62(3): 360-368, 2022. tab
Artículo en Español | LILACS, LIVECS | ID: biblio-1395352

RESUMEN

La Ingeniería Sanitaria surge como una rama de la ingeniería que involucra tanto materias propias de la ingeniería tales como: matemáticas, física, química hidráulica o mecánica, como aquellas relacionada con la medicina y la higiene, tales como la microbiología y conservación. Tiene como función principal crear y fomentar condiciones de salubridad en las poblaciones siendo vigilante de las aguas, el aire y la tierra, evitando que la contaminación alcance a los seres humanos. En Perú, la ingeniería sanitaria se creó como un apéndice de la ingeniería civil, pero pronto tomó el lugar merecido, declarándose una carrera de ingeniería independiente. Actualmente, la Ingeniería sanitaria es la encargada de llevar agua potabilizada a la población, y tratar las aguas servidas. Por otra parte, con la llegada del SARS-CoV-2, el mundo fue sacudido, y una situación de pandemia emergió, lo que hizo que los diferentes países tomasen las acciones necesarias, tal como sucedió con el Perú. Allí, la Ingeniería Sanitaria, accionó sus funciones, buscando la potabilización del agua de consumo. En estos tiempos de pandemia, también determinaron el resguardo de la población, lo que fomentó la educación remota. En el caso de la Ingeniería Sanitaria, los laboratorios presenciales y convencionales fueron sustituidos por laboratorios virtuales y remotos, lo cual permitió que la educación continuase sin contratiempos(AU)


Sanitary Engineering emerges as a branch of engineering that involves both engineering subjects such as: mathematics, physics, hydraulic or mechanical chemistry, as well as those related to medicine and hygiene, such as microbiology and conservation. Its main function is to create and promote healthy conditions in the populations, being vigilant of the waters, the air and the land, preventing contamination from reaching human beings. In Peru, sanitary engineering was created as an appendix to civil engineering, but it soon took its deserved place, declaring itself an independent engineering career. Currently, Sanitary Engineering is in charge of bringing drinking water to the population, and treating wastewater. On the other hand, with the arrival of SARS-CoV-2, the world was shaken, and a pandemic situation emerged, which made the different countries take the necessary actions, as happened with Peru. Over there, the Sanitary Engineering, activated its functions, seeking the potabilization of drinking water. In these times of pandemic, they also determined the protection of the population, which promoted remote education. In the case of Sanitary Engineering, face-to-face and conventional laboratories were replaced by virtual and remote laboratories, which allowed education to continue without setbacks(AU)


Asunto(s)
Ingeniería Sanitaria , Educación a Distancia , COVID-19 , Saneamiento , Purificación del Agua , Contaminación Ambiental , Pandemias , Acceso a Medicamentos Esenciales y Tecnologías Sanitarias
12.
Microbiol Spectr ; 9(3): e0138021, 2021 12 22.
Artículo en Inglés | MEDLINE | ID: mdl-34817232

RESUMEN

The hospital environment has been reported as a source of transmission events and outbreaks of carbapenemase-producing Enterobacterales. Interconnected plumbing systems and the microbial diversity in these reservoirs pose a challenge for outbreak investigation and control. A total of 133 clinical and environmental OXA-48-producing Enterobacter cloacae isolates collected between 2015 and 2021 were characterized by whole-genome sequencing (WGS) to investigate a prolonged intermittent outbreak involving 41 patients in the hematological unit. A mock-shower experiment was performed to investigate the possible acquisition route. WGS indicated the hospital water environmental reservoir as the most likely source of the outbreak. The lack of diversity of the blaOXA-48-like harbouring plasmids was a challenge for data interpretation. The detection of blaOXA-48-like-harboring E. cloacae strains in the shower area after the mock-shower experiment provided strong evidence that showering is the most likely route of acquisition. Initially, in 20 out of 38 patient rooms, wastewater traps and drains were contaminated with OXA-48-positive E. cloacae. Continuous decontamination using 25% acetic acid three times weekly was effective in reducing the trap/drain positivity in monthly environmental screening but not in reducing new acquisitions. However, the installation of removable custom-made shower tubs did prevent new acquisitions over a subsequent 12-month observation period. In the present study, continuous decontamination was effective in reducing the bacterial burden in the nosocomial reservoirs but was not sufficient to prevent environment-to-patient transmission in the long term. Construction interventions may be necessary for successful infection prevention and control. IMPORTANCE The hospital water environment can be a reservoir for a multiward outbreak, leading to acquisitions or transmissions of multidrug-resistant organisms in a hospital setting. The majority of Gram-negative bacteria are able to build biofilms and persist in the hospital plumbing system over a long period of time. The elimination of the reservoir is essential to prevent further transmission and spread, but proposed decontamination regimens, e.g., using acetic acid, can only suppress but not fully eliminate the environmental reservoir. In this study, we demonstrated that colonization with multidrug-resistant organisms can be acquired by showering in showers with contaminated water traps and drains. A construction intervention by installing removable and autoclavable shower inserts to avoid sink contact during showering was effective in containing this outbreak and may be a viable alternative infection prevention and control measure in outbreak situations involving contaminated shower drains and water traps.


Asunto(s)
Proteínas Bacterianas/genética , Enterobacter cloacae/genética , Infecciones por Enterobacteriaceae/epidemiología , Infecciones por Enterobacteriaceae/prevención & control , Control de Infecciones/métodos , Ingeniería Sanitaria/métodos , beta-Lactamasas/genética , Proteínas Bacterianas/metabolismo , Biopelículas/crecimiento & desarrollo , Infección Hospitalaria/epidemiología , Brotes de Enfermedades , Enterobacter cloacae/efectos de los fármacos , Enterobacter cloacae/metabolismo , Genoma Bacteriano/genética , Humanos , Unidades de Cuidados Intensivos , Microbiología del Agua , Secuenciación Completa del Genoma , beta-Lactamasas/metabolismo
13.
Infect Dis Clin North Am ; 35(3): 667-695, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34362538

RESUMEN

Health care facility water systems have been associated with the transmission of opportunistic premise plumbing pathogens such as Legionella and nontuberculous mycobacteria. These pathogens can enter a building's water system in low numbers and then proliferate when conditions are conducive to their growth. Patients and residents in health care facilities are often at heightened risk for opportunistic infections, and cases and outbreaks in the literature highlight the importance of routine water management programs and occasions for intervention to prevent additional cases. A multidisciplinary proactive approach to water safety is critical for sustained prevention of health care-associated water-related infections.


Asunto(s)
Atención a la Salud , Legionella , Micobacterias no Tuberculosas , Infecciones Oportunistas/prevención & control , Ingeniería Sanitaria , Abastecimiento de Agua/normas , Humanos , Medición de Riesgo
14.
Elife ; 102021 04 09.
Artículo en Inglés | MEDLINE | ID: mdl-33835026

RESUMEN

We conducted a controlled before-and-after trial to evaluate the impact of an onsite urban sanitation intervention on the prevalence of enteric infection, soil transmitted helminth re-infection, and diarrhea among children in Maputo, Mozambique. A non-governmental organization replaced existing poor-quality latrines with pour-flush toilets with septic tanks serving household clusters. We enrolled children aged 1-48 months at baseline and measured outcomes before and 12 and 24 months after the intervention, with concurrent measurement among children in a comparable control arm. Despite nearly exclusive use, we found no evidence that intervention affected the prevalence of any measured outcome after 12 or 24 months of exposure. Among children born into study sites after intervention, we observed a reduced prevalence of Trichuris and Shigella infection relative to the same age group at baseline (<2 years old). Protection from birth may be important to reduce exposure to and infection with enteric pathogens in this setting.


Asunto(s)
Infecciones Bacterianas/prevención & control , Helmintiasis/prevención & control , Ingeniería Sanitaria , Cuartos de Baño , Salud Urbana , Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/epidemiología , Infecciones Bacterianas/microbiología , Preescolar , Diarrea/epidemiología , Diarrea/microbiología , Diarrea/prevención & control , Disentería Bacilar/epidemiología , Disentería Bacilar/microbiología , Disentería Bacilar/prevención & control , Femenino , Helmintiasis/diagnóstico , Helmintiasis/epidemiología , Helmintiasis/parasitología , Humanos , Lactante , Masculino , Mozambique/epidemiología , Prevalencia , Reinfección , Características de la Residencia , Suelo/parasitología , Factores de Tiempo , Tricuriasis/epidemiología , Tricuriasis/parasitología , Tricuriasis/prevención & control
16.
Ann Glob Health ; 87(1): 21, 2021 02 24.
Artículo en Inglés | MEDLINE | ID: mdl-33665143

RESUMEN

This Viewpoint calls for a greater understanding of the role that water plays in the transmission of anti-microbial resistance and covid-19 in protracted urban armed conflict, in order to develop a 'pathogen-safe' practice. It argues that dealing with the twin threats is difficult enough in the best of circumstances, and is so little understood in war zones that surgeons and water engineers now question if their practice does more harm than good. Experience suggests that the known transmission routes are complicated by a great number of factors, including the entry of heavy metals through bullets in patients' wounds, hospital over-crowding, mutation in treated water or wastewater, and other threats which endure long after the bombing has stopped. The skeleton research agenda proposes greater sewage surveillance, testing of phages and monitoring of treatment designed to dispel or substantiate these assertions.


Asunto(s)
COVID-19 , Transmisión de Enfermedad Infecciosa/prevención & control , Salud Pública , Ingeniería Sanitaria , COVID-19/epidemiología , COVID-19/prevención & control , COVID-19/transmisión , Reservorios de Enfermedades , Farmacorresistencia Microbiana , Humanos , Fenómenos Microbiológicos , SARS-CoV-2 , Ingeniería Sanitaria/métodos , Ingeniería Sanitaria/normas
18.
Indoor Air ; 31(5): 1427-1440, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33569864

RESUMEN

Aerosols are readily transported on airstreams through building sanitary plumbing and sewer systems, and those containing microbial pathogens (known as bioaerosols) are recognized as contributors to infection spread within buildings. When a defect occurs in the sanitary plumbing system that affects the system integrity, a cross-transmission route is created that can enable the emission of bioaerosols from the system into the building. These emission occurrences are characterized as short-burst events (typically <1 min in duration) which make them difficult to detect and predict. The characterization of these emission events is the focus of this research. Two methods were used to characterize bioaerosol emission events in a full-scale test rig: (a) an Aerodynamic Particle Sizer (APS) for particle size distribution and concentrations; and (b) a slit-to-agar sampler to enumerate the ingress of a viable tracer microorganism (Pseudomonas putida). The APS data confirmed that most particles (>99.5%) were <5 µm and were therefore considered aerosols. Particles generated within the sanitary plumbing system as a result of a toilet flush leads to emissions into the building during system defect conditions with an equivalence of someone talking loudly for over 6 and a half minutes. There were no particles detected of a size >11 µm anywhere in the system. Particle count was influenced by toilet flush volume, but it was not possible to determine if there was any direct influence from airflow rate since both particle and biological data showed no correlation with upward airflow rates and velocities. Typical emissions resulting from a 6 L toilet flush were in the range of 280-400 particles per second at a concentration of typically 9-12 number per cm3 and a total particle count in the region of 3000 to 4000 particles, whereas the peak emissions from a 1.2 L toilet flush were 60-80 particles per second at a concentration of 2.4-3 number per cm3 and a total particle count in the region of 886 to 1045 particles. The reduction in particles is in direct proportion to the reduction in toilet flush volume. The slit-to-agar sampler was able to provide viable time course CFU data and confirmed the origin of the particles to be the tracer microorganism flushed into the system. The time course data also have characteristics consistent with the unsteady nature of a toilet flush.


Asunto(s)
Contaminación del Aire Interior/análisis , Aparatos Sanitarios/estadística & datos numéricos , Tamaño de la Partícula , Pseudomonas putida/aislamiento & purificación , Ingeniería Sanitaria/estadística & datos numéricos , COVID-19/transmisión , Monitoreo del Ambiente , Humanos
19.
J Water Health ; 18(5): 820-834, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33095203

RESUMEN

Private well water systems in rural areas that are improperly maintained will result in poor drinking water quality, loss of water supply, and pose human health risk. The purpose of this study was to investigate the occurrence of fecal indicator bacteria (FIB) and opportunistic pathogens in private well water in rural areas surrounding New Orleans, Louisiana. Our results confirmed the ubiquitous nature of Legionella (86.7%) and mycobacteria (68.1%) in private well water in the study area, with gene concentration ranged from 0.60 to 5.53 and 0.67 to 5.95 Log10 of GC/100 mL, respectively. Naegleria fowleri target sequence was detected in 16.8% and Escherichia coli was detected in 43.4% of the water samples. Total coliform, as well as Legionella and mycobacteria genetic markers' concentrations were significantly reduced by 3-minute flushing. Next-generation sequencing (NGS) data indicated that the abundance of bacterial species was significantly increased in water collected in kitchens compared with samples from wells directly. This study provided integrated knowledge on the persistence of pathogenic organisms in private well water. Further study is needed to explore the presence of clinical species of those opportunistic pathogens in private well water systems to elucidate the health risk.


Asunto(s)
Agua Potable , Ingeniería Sanitaria , Humanos , Legionella/genética , Louisiana , Abastecimiento de Agua
20.
PLoS One ; 15(9): e0238385, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32936810

RESUMEN

A lack of replicable test systems that realistically simulate hot water premise plumbing conditions at the laboratory-scale is an obstacle to identifying key factors that support growth of opportunistic pathogens (OPs) and opportunities to stem disease transmission. Here we developed the convectively-mixed pipe reactor (CMPR) as a simple reproducible system, consisting of off-the-shelf plumbing materials, that self-mixes through natural convective currents and enables testing of multiple, replicated, and realistic premise plumbing conditions in parallel. A 10-week validation study was conducted, comparing three pipe materials (PVC, PVC-copper, and PVC-iron; n = 18 each) to stagnant control pipes without convective mixing (n = 3 each). Replicate CMPRs were found to yield consistent water chemistry as a function of pipe material, with differences becoming less discernable by week 9. Temperature, an overarching factor known to control OP growth, was consistently maintained across all 54 CMPRs, with a coefficient of variation <2%. Dissolved oxygen (DO) remained lower in PVC-iron (1.96 ± 0.29 mg/L) than in PVC (5.71 ± 0.22 mg/L) or PVC-copper (5.90 ± 0.38 mg/L) CMPRs as expected due to corrosion. Further, DO in PVC-iron CMPRs was 33% of that observed in corresponding stagnant pipes (6.03 ± 0.33 mg/L), demonstrating the important role of internal convective mixing in stimulating corrosion and microbiological respiration. 16S rRNA gene amplicon sequencing indicated that both bulk water (Padonis = 0.001, R2 = 0.222, Pbetadis = 0.785) and biofilm (Padonis = 0.001, R2 = 0.119, Pbetadis = 0.827) microbial communities differed between CMPR versus stagnant pipes, consistent with creation of a distinct ecological niche. Overall, CMPRs can provide a more realistic simulation of certain aspects of premise plumbing than reactors commonly applied in prior research, at a fraction of the cost, space, and water demand of large pilot-scale rigs.


Asunto(s)
Agua Potable/efectos adversos , Agua Potable/microbiología , Ingeniería Sanitaria/instrumentación , Microbiología del Agua , Biopelículas/crecimiento & desarrollo , Fenómenos Químicos , Cobre/química , Diseño de Equipo , Humanos , Hierro/química , Microbiota/genética , Modelos Biológicos , Infecciones Oportunistas/etiología , Infecciones Oportunistas/microbiología , Cloruro de Polivinilo/química , ARN Ribosómico 16S/genética , Temperatura , Abastecimiento de Agua
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