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1.
Environ Sci Technol ; 58(4): 2038-2047, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38241248

RESUMO

Single-particle inductively coupled plasma mass spectrometry (spICP-MS) has been used to characterize metallic nanoparticles (NPs) assuming that all NPs are spherical and composed of pure element. However, environmental NPs generally do not meet these criteria, suggesting that spICP-MS may underestimate their true sizes. This study employed a system hyphenating the atomizer (ATM), differential mobility analyzer (DMA), and spICP-MS to characterize metallic NPs in tap water. Its performance was validated by using reference Au nanoparticles (AuNPs) and Ag-shelled AuNPs. The hyphenated system can determine the actual size and metal composition of both NPs with additional heating after ATM, while stand-alone spICP-MS misidentified the Ag-shelled AuNPs as smaller individual AgNPs and AuNPs. Dissolved metal ions could introduce artifact NPs after heating but could be eliminated by centrifugation. The hyphenated system was applied to characterize Fe-containing and Pb-containing NPs resulting from the corrosion of plumbing materials in tap water. The mode sizes of Fe-containing and Pb-containing NPs were determined to be 110 and 100 nm and the particle number concentrations were determined to be 4.99 × 107 and 1.40 × 106 #/mL, respectively. Cautions should be paid to potential changes in particle size induced by heating for metallic NPs with a low melting point or a high organic content.


Assuntos
Nanopartículas Metálicas , Nanopartículas Metálicas/química , Ouro/química , Chumbo , Engenharia Sanitária , Corrosão , Nebulizadores e Vaporizadores , Tamanho da Partícula , Água
2.
Water Res ; 251: 121098, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38219686

RESUMO

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.


Assuntos
Água Potável , Engenharia Sanitária , Abastecimento de Água , Cloraminas , Cloro , Temperatura , Oxirredução
3.
Am J Infect Control ; 52(3): 337-343, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37778710

RESUMO

BACKGROUND: Aquatic opportunistic pathogen Aeromonas hydrophila, known to persist in low-nutrient chlorinated waters, can cause life-threatening infections. Two intensive care units experienced a cluster of Aeromonas infections following outdoor temperature spikes coinciding with recurrent plumbing issues, with fatalities due to severe underlying comorbidities co-occurring with extensively-drug resistant (XDR) Aeromonas. METHODS: We investigated this cluster using whole genome sequencing to assess genetic relatedness of isolates and identify antimicrobial resistance determinants. Three A. hydrophila were isolated from patients staying in or adjacent to rooms with plumbing issues during or immediately after periods of elevated outdoor temperatures. Sinks and faucets were swabbed for culture. RESULTS: All A. hydrophila clinical isolates exhibited carbapenem resistance but were not genetically related. Diverse resistance determinants corresponding to extensively-drug resistant were found, including co-occurring KPC-3 and VIM-2, OXA-232, and chromosomal CphA-like carbapenemase genes, contributing to major treatment challenges. All 3 patients were treated with multiple antibiotic regimens to overcome various carbapenemase classes and expired due to underlying comorbidities. Environmental culture yielded no Aeromonas. CONCLUSIONS: While the investigation revealed no singular source of contamination, it supports a possible link between plumbing issues, elevated outdoor temperatures and incidence of nosocomial Aeromonas infections. The diversity of carbapenemase genes detected in these wastewater-derived Aeromonas warrants heightened infection prevention precautions during periods of plumbing problems especially with heat waves.


Assuntos
Aeromonas , Proteínas de Bactérias , Infecção Hospitalar , Humanos , Aeromonas hydrophila/genética , Engenharia Sanitária , Infecção Hospitalar/epidemiologia , Temperatura Alta , beta-Lactamases/genética , Aeromonas/genética , Antibacterianos , Testes de Sensibilidade Microbiana
4.
Environ Sci Technol ; 57(50): 21382-21394, 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38071676

RESUMO

In-building disinfectants are commonly applied to control the growth of pathogens in plumbing, particularly in facilities such as hospitals that house vulnerable populations. However, their application has not been well optimized, especially with respect to interactive effects with pipe materials and potential unintended effects, such as enrichment of antibiotic resistance genes (ARGs) across the microbial community. Here, we used triplicate convectively mixed pipe reactors consisting of three pipe materials (PVC, copper, and iron) for replicated simulation of the distal reaches of premise plumbing and evaluated the effects of incrementally increased doses of chlorine, chloramine, chlorine dioxide, and copper-silver disinfectants. We used shotgun metagenomic sequencing to characterize the resulting succession of the corresponding microbiomes over the course of 37 weeks. We found that both disinfectants and pipe material affected ARG and microbial community taxonomic composition both independently and interactively. Water quality and total bacterial numbers were not found to be predictive of pathogenic species markers. One result of particular concern was the tendency of disinfectants, especially monochloramine, to enrich ARGs. Metagenome assembly indicated that many ARGs were enriched specifically among the pathogenic species. Functional gene analysis was indicative of a response of the microbes to oxidative stress, which is known to co/cross-select for antibiotic resistance. These findings emphasize the need for a holistic evaluation of pathogen control strategies for plumbing.


Assuntos
Desinfetantes , Água Potável , Engenharia Sanitária , Desinfetantes/farmacologia , Abastecimento de Água , Antibacterianos/farmacologia , Cobre , Proliferação de Células
5.
Environ Pollut ; 337: 122520, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37678732

RESUMO

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).


Assuntos
Água Potável , Engenharia Sanitária , Cobre/análise , Chumbo , Abastecimento de Água , Polietileno , Descontaminação , Biofilmes
6.
Mol Ecol ; 32(20): 5590-5608, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37728237

RESUMO

Mesophotic coral ecosystems (MCEs) are tropical reefs found at depths of ~30-150 m, below the region most heavily impacted by heat stress and other disturbances. Hence, MCEs may serve as potential refugia for threatened shallow reefs, but they also harbour depth-endemic fauna distinct from shallow reefs. Previous studies have characterized biodiversity patterns along depth gradients, but focussed primarily on conspicuous taxa (fishes, corals, etc.). Environmental DNA (eDNA) metabarcoding offers a more holistic approach to assess biodiversity patterns across the tree of life. Here, we use three metabarcoding assays targeting fishes (16S rRNA), eukaryotes (18S rDNA) and metazoans (COI) to assess biodiversity change from the surface to ~90 m depth across 15-m intervals at three sites within the Hawaiian Archipelago. We observed significant community differences between most depth zones, with distinct zonation centred at 45-60 m for eukaryotes and metazoans, but not for fishes. This finding may be attributable to the higher mobility of reef fishes, although methodological limitations are likely a contributing factor. The possibility for MCEs to serve as refugia is not excluded for fishes, but invertebrate communities >45 m are distinct, indicating limited connectivity for the majority of reef fauna. This study provides a new approach for surveying biodiversity on MCEs, revealing patterns in a much broader context than the limited-taxon studies that comprise the bulk of our present knowledge.


Assuntos
Antozoários , DNA Ambiental , Animais , Recifes de Corais , Ecossistema , DNA Ambiental/genética , Engenharia Sanitária , RNA Ribossômico 16S , Biodiversidade , Antozoários/genética , Peixes/genética
7.
Environ Sci Technol ; 57(36): 13612-13624, 2023 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-37643149

RESUMO

Hot water building plumbing systems are vulnerable to the proliferation of opportunistic pathogens (OPs), including Legionella pneumophila and Mycobacterium avium. Implementation of copper as a disinfectant could help reduce OPs, but a mechanistic understanding of the effects on the microbial community under real-world plumbing conditions is lacking. Here, we carried out a controlled pilot-scale study of hot water systems and applied shotgun metagenomic sequencing to examine the effects of copper dose (0-2 mg/L), orthophosphate corrosion control agent, and water heater anode materials (aluminum vs magnesium vs powered anode) on the bulk water and biofilm microbiome composition. Metagenomic analysis revealed that, even though a copper dose of 1.2 mg/L was required to reduce Legionella and Mycobacterium numbers, lower doses (e.g., ≤0.6 mg/L) measurably impacted the broader microbial community, indicating that the OP strains colonizing these systems were highly copper tolerant. Orthophosphate addition reduced bioavailability of copper, both to OPs and to the broader microbiome. Functional gene analysis indicated that both membrane damage and interruption of nucleic acid replication are likely at play in copper inactivation mechanisms. This study identifies key factors (e.g., orthophosphate, copper resistance, and anode materials) that can confound the efficacy of copper for controlling OPs in hot water plumbing.


Assuntos
Microbiota , Água , Cobre , Metagenômica , Engenharia Sanitária , Eletrodos , Fosfatos
8.
Environ Sci Pollut Res Int ; 30(41): 94878-94889, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37542688

RESUMO

The microbial community of the landfill undergoing aerobic stabilization process by aeration engineering was investigated. The municipal solid wastes (MSWs) were sampled from two aeration well sites with different landfill temperatures (65.5°C and 41.7°C) under higher and lower stabilization level. The physical component, chemical property, and microbial population of MSWs were analyzed and compared. The result showed that the phylum Firmicutes was dominant in the aerobic landfill; and the genus Weissella and Syntrophaceticus were more abundant in high, and low temperature site, respectively. The bacterial distribution showed difference on two temperature sites and four landfill depths, mainly affected by the ammonia-nitrogen and moisture content of MSWs. The ecological profiles of the microorganisms responded the aeration engineering were predicted. The anaerobic hydrolytic and acetogenic microorganisms were decreased in abundance, while the facultative Lactobacillus increased when the landfill under a higher stabilization level. The function abundances of methane oxidation, sulfide oxidation, and aerobic chemoheterotrophy were enriched by aeration engineering, which was the microbial mechanism for accelerating the stabilization process of landfill.


Assuntos
Bactérias , Oxigênio , Instalações de Eliminação de Resíduos , Resíduos Sólidos , Pequim , Bactérias/classificação , Bactérias/metabolismo , Engenharia Sanitária/métodos , Biodegradação Ambiental
9.
J Water Health ; 21(7): 884-894, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37515560

RESUMO

Legionella concentrations in drinking water have been regulated for decades and are evaluated with regard to their concentrations in drinking water plumbing systems (DWPS). The respective action levels differ at the international level. In Germany, the Federal Environment Agency (UBA) specifies the application of ISO 11731 for the detection of legionella in drinking water and gives a binding recommendation for the methods to be used for culturing and evaluation. Effective from 01 March 2019, the UBA recommendation was revised. The utilized culture media in the culture approach were altered, consequently affecting the spectrum of legionella colonies detected in drinking water. Using data from a routine legionella monitoring of a large laboratory, over a period of 6 years and 17,270 individual drinking water samples, allowed us to assess the impact of the alteration on the assessment of DWPS. By comparing the amount of action level exceedances before and after the method change, it could be demonstrated that exceedances are reported significantly more often under the new method. Consequently, the corresponding action level for evaluation of legionella contamination and the resulting risk to human health needs to be revised to avoid the misleading impression of increased health risk.


Assuntos
Água Potável , Legionella pneumophila , Legionella , Humanos , Água Potável/análise , Microbiologia da Água , Engenharia Sanitária , Alemanha , Abastecimento de Água
10.
Antimicrob Resist Infect Control ; 12(1): 58, 2023 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-37337245

RESUMO

BACKGROUND: Accumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures. METHODS: Environmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci. RESULTS: The CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms. CONCLUSIONS: Our findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system.


Assuntos
Citrobacter freundii , Águas Residuárias , Humanos , Idoso , Citrobacter freundii/genética , Engenharia Sanitária , Estudos Retrospectivos , Hospitais , Células Clonais
11.
Zebrafish ; 20(3): 122-125, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37310180

RESUMO

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.


Assuntos
Engenharia Sanitária , Peixe-Zebra , Animais , Fertilidade , Laboratórios , Longevidade
12.
Water Res ; 241: 120149, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37270942

RESUMO

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.


Assuntos
Engenharia Sanitária , Qualidade da Água , Microbiologia da Água , Abastecimento de Água , Pseudomonas
13.
Mol Ther ; 31(6): 1577-1595, 2023 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-37165619

RESUMO

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.


Assuntos
RNA Longo não Codificante , Humanos , RNA Longo não Codificante/metabolismo , Engenharia Sanitária , RNA não Traduzido
14.
Environ Sci Technol ; 57(16): 6360-6372, 2023 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-37036108

RESUMO

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.


Assuntos
Água Potável , Engenharia Sanitária , Abastecimento de Água , Habitação , Microbiologia da Água
15.
Sci Total Environ ; 879: 162975, 2023 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-36965725

RESUMO

Water conservation measures are increasing in response to regulatory requirements addressing the need for lower environmental footprint and in response to water shortages. In households with lead service lines (LSLs), lowering consumption can adversely impact lead release as it will increase stagnation. Using a lead dissolution model and data from extensive pilot studies on excavated LSLs, the impact of adaptation to different water conservation strategies on dissolved lead contamination at the kitchen tap is assessed under three water qualities and three LSL lengths (3, 14 and 30 m) using hydraulic and water quality modelling. Consumers' behavioural variability is also assessed based on integration of EPANET and results of the stochastic water demand model SIMDEUM. Demand reduction increased the dissolved lead concentrations (Pbdiss) at the end of the LSL with mean values ranging from 28.4 to 63.3 µg/L (without corrosion control) and from 4.6 to 9.9 µg/L with corrosion control (addition of orthophosphate and pH adjustment). Adding orthophosphate (1 mg P/L) to the water reduces the mean Pbdiss values at the kitchen tap from 7.1 µg/L to 1.2 µg/L for a high water demand scenario and from 31.2 to 4.9 µg/L for a low water demand scenario. Finally, the Integrated Exposure Uptake Biokinetic (IEUBK) model is used to predict the potential blood lead levels (BLLs) for children aged 0-84 months. Results showed that the orthophosphate addition of only 1 mg P/L can significantly decrease the proportion of children with a BLL >5 µg/dL, from 82 % to 17 %, under the most extreme water conservation scenario studied, using the 90th percentile of Pbdiss concentrations during usage at kitchen tap. Wide variations of Pbdiss concentrations at the kitchen tap were calculated at times of use over a week (up to 155 µg/L in lower demand scenarios, without corrosion control) showing evident limitations of single random daytime sampling.


Assuntos
Água Potável , Poluentes Químicos da Água , Criança , Humanos , Qualidade da Água , Engenharia Sanitária , Abastecimento de Água , Chumbo/análise , Ingestão de Líquidos , Poluentes Químicos da Água/análise , Fosfatos
16.
Environ Sci Technol ; 57(13): 5453-5463, 2023 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-36952669

RESUMO

Microbial communities in premise plumbing systems were investigated after more than 2 months of long-term stagnation, during a subsequent flushing event, and during post-flush stagnation. Water samples were collected from showers in buildings supplied with chlorinated groundwater, untreated groundwater, and chloraminated surface water. The building supplied with chlorinated groundwater generally had the lowest bacterial concentrations across all sites (ranging from below quantification limit to 5.2 log copies/L). For buildings supplied with untreated groundwater, bacterial concentrations (5.0 to 7.6 log copies/L) and microbial community diversity index (ACE) values were consistent throughout sampling. Nontuberculous mycobacteria (NTM) and Legionella pneumophila were not detected in any groundwater-supplied buildings. Total bacteria, Legionella spp., and NTM were abundant in the surface water-supplied buildings following long-term stagnation (up to 7.6, 6.2, and 7.6 log copies/L, respectively). Flushing decreased these concentrations by ∼1 to >4 log units and reduced microbial community diversity, but the communities largely recovered within a week of post-flush stagnation. The results suggest that buildings supplied with disinfected surface water are more likely than buildings supplied with treated or untreated groundwater to experience deleterious changes in microbiological water quality during stagnation and that the water quality improvements from flushing with chloraminated water, while substantial, are short-lived.


Assuntos
Água Potável , Água Subterrânea , Legionella pneumophila , Legionella , Qualidade da Água , Abastecimento de Água , Engenharia Sanitária , Microbiologia da Água
17.
Environ Sci Technol ; 57(8): 3248-3259, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36795589

RESUMO

COVID-19 pandemic-related building restrictions heightened drinking water microbiological safety concerns post-reopening due to the unprecedented nature of commercial building closures. Starting with phased reopening (i.e., June 2020), we sampled drinking water for 6 months from three commercial buildings with reduced water usage and four occupied residential households. Samples were analyzed using flow cytometry and full-length 16S rRNA gene sequencing along with comprehensive water chemistry characterization. Prolonged building closures resulted in 10-fold higher microbial cell counts in the commercial buildings [(2.95 ± 3.67) × 105 cells mL-1] than in residential households [(1.11 ± 0.58) × 104 cells mL-1] with majority intact cells. While flushing reduced cell counts and increased disinfection residuals, microbial communities in commercial buildings remained distinct from those in residential households on the basis of flow cytometric fingerprinting [Bray-Curtis dissimilarity (dBC) = 0.33 ± 0.07] and 16S rRNA gene sequencing (dBC = 0.72 ± 0.20). An increase in water demand post-reopening resulted in gradual convergence in microbial communities in water samples collected from commercial buildings and residential households. Overall, we find that the gradual recovery of water demand played a key role in the recovery of building plumbing-associated microbial communities as compared to short-term flushing after extended periods of reduced water demand.


Assuntos
COVID-19 , Água Potável , Microbiota , Humanos , Engenharia Sanitária , Água Potável/microbiologia , Abastecimento de Água , RNA Ribossômico 16S/genética , Pandemias , Qualidade da Água , Microbiologia da Água
18.
Nat Commun ; 14(1): 358, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36690620

RESUMO

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.


Assuntos
Exantema , Engenharia Sanitária , Humanos , Espanha , Heterogeneidade Genética , Resolução de Problemas
19.
Work ; 75(2): 507-520, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36641707

RESUMO

BACKGROUND: Recently the plumbing trade has transitioned from traditional copper piping to flexible plastic piping (PEX) for residential water distribution systems. However, there has been very limited research into the ergonomic implications of the modernized processes. OBJECTIVE: This research documents the physical workload and risks of musculoskeletal disorders (MSDs) with the use of new tools and processes for joining piping. The research also identifies the factors which can facilitate or limit the use of new ergonomically beneficial tools. METHODS: This mixed methods research included workplace observations, interviews, an experiment, a survey of plumbers in residential construction and focus groups with both plumbers and plumbing contractors. RESULTS: Advantages and disadvantages of the various techniques for joining pipes showed that manual crimping has advantages (i.e., productivity and lower cost) that make it desirable for plumbing contractors. Power devices, which were not widely used, have great potential to reduce MSD risks especially if the size and weight of the tools decreases with newer technologies. A continuing barrier is the cost of power equipment. CONCLUSION: The move to provide ergonomically beneficial tools was not as rapid as the willingness to change piping materials. Productivity and costs of tools are barriers to ergonomic interventions.


Assuntos
Doenças Musculoesqueléticas , Doenças Profissionais , Humanos , Engenharia Sanitária , Ergonomia/métodos , Doenças Musculoesqueléticas/etiologia , Local de Trabalho , Inquéritos e Questionários , Doenças Profissionais/etiologia , Doenças Profissionais/prevenção & controle
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