scholarly journals Disinfection exhibits systematic impacts on the drinking water microbiome

2019 ◽  
Author(s):  
Zihan Dai ◽  
Maria C. Sevillano-Rivera ◽  
Szymon T. Calus ◽  
Q. Melina Bautista-de los Santos ◽  
A. Murat Eren ◽  
...  

ABSTRACTLimiting microbial growth during drinking water distribution is achieved either by maintaining a disinfectant residual or through nutrient limitation without the use of a disinfectant. The impact of these contrasting approaches on the drinking water microbiome is not systematically understood. We utilized genome-resolved metagenomics to compare the structure, metabolic traits, and population genomes of drinking water microbiomes across multiple full-scale drinking water systems utilizing these two-distinct microbial growth control strategies. Microbial communities cluster together at the structural- and functional potential-level based on the presence or absence of a disinfectant residual. Disinfectant residual concentrations alone explained 17 and 6.5% of the variance in structure and functional potential of the drinking water microbiome, respectively, despite including samples from multiple drinking water systems with variable source waters and source water communities, treatment strategies, and chemical compositions. The drinking water microbiome is structurally and functionally less diverse and less variable across disinfected systems as compared to non-disinfected systems. While bacteria were the most abundant domain, archaea and eukaryota were more abundant in non-disinfected and disinfected systems, respectively. Community-level differences in functional potential were driven by enrichment of genes associated with carbon and nitrogen fixation in non-disinfected systems and γ-aminobutyrate metabolism in disinfected systems which may be associated with the recycling of amino acids. Metagenome-assembled genome-level analyses for a subset of phylogenetically related microorganisms suggests that disinfection may select for microorganisms capable of using fatty acids, presumably from microbial decay products, via the glyoxylate cycle. Overall, we find that disinfection exhibits systematic and consistent selective pressures on the drinking water microbiome and may select for microorganisms able to utilize microbial decay products originating from disinfection inactivated microorganisms.

2019 ◽  
Author(s):  
Maria Sevillano ◽  
Zihan Dai ◽  
Szymon Calus ◽  
Quyen M Bautista-de los Santos ◽  
A. Murat Eren ◽  
...  

AbstractAntimicrobial resistance (AMR) in drinking water has received less attention than counterparts in the urban water cycle. While culture-based techniques or gene-centric PCR have been used to probe the impact of treatment approaches (e.g., disinfection) on AMR in drinking water, to our knowledge there is no systematic comparison of AMR traits between disinfected and disinfectant residual-free drinking water systems. We use metagenomics to assess the associations between disinfectant residuals and AMR prevalence and its host association in full-scale drinking water distribution systems (DWDSs). The differences in AMR profiles between DWDSs are associated with the presence or absence of disinfectant. Further, AMR genes and mechanisms enriched in disinfected systems are associated with drug classes primarily linked to nontuberculous mycobacteria (NTM). Finally, evaluation of metagenome assembled genomes (MAGs) of NTM indicates that they possess AMR genes conferring intrinsic resistance to key antibiotics, whereas such NTM genomes were not detected in disinfectant residual free DWDSs. Thus, disinfection may not only influence the AMR profiles of the drinking water microbiome but also select for NTM with intrinsic AMR.


Author(s):  
J. Wren Tracy ◽  
Amy Guo ◽  
Kaida Liang ◽  
Jamie Bartram ◽  
Michael Fisher

Exposure to toxic metals and metalloids (TMs) such as arsenic and lead at levels of concern is associated with lifelong adverse health consequences. As exposure to TMs from paint, leaded gasoline, canned foods, and other consumer products has decreased in recent decades, the relative contribution of drinking water to environmental TM exposure and associated disease burdens has increased. We conducted a rapid review from June to September 2019 to synthesize information on the sources of TM contamination in small rural drinking water systems and solutions to TM contamination from these sources, with an emphasis on actionable evidence applicable to small rural drinking water systems worldwide. We reviewed publications from five databases (ProQuest, PubMed, Web of Science, Embase, and Global Health Library) as well as grey literature from expert groups including WHO, IWA, and others; findings from 61 eligible review publications were synthesized. Identified sources of TMs in included studies were natural occurrence (geogenic), catchment pollution, and corrosion of water distribution system materials. The review found general support for preventive over corrective actions. This review informs a useful planning and management framework for preventing and mitigating TM exposure from drinking water based on water supply characteristics, identified contamination sources, and other context-specific variables.


Water Policy ◽  
2014 ◽  
Vol 17 (2) ◽  
pp. 349-369 ◽  
Author(s):  
Megan Kot ◽  
Graham A. Gagnon ◽  
Heather Castleden

Fundamental to community health and well-being is the capacity to access a sustainable supply of safe drinking water. Small community drinking water systems are the most vulnerable to contamination, and struggle to secure the funds necessary to improve water treatment and delivery systems, and meet increasingly stringent drinking water quality regulations. Little is known of the contextual and cultural differences between communities and the impact this has on regulatory compliance. This study explored the experiences and impact of individual actors within seven small community drinking water systems in locations across Canada. Qualitative, in-person interviews were conducted with water operators, consumers, and decision-makers in each community, and these findings were analysed thematically. Findings from the study show that communities approach and align with compliance challenges in three distinct ways: by adopting regulator-provided or regulator-driven solutions, by adopting an existing improvement framework (i.e. regionalization), or through reinvention to address a new issue or concern. Policy-makers looking to align small communities with appropriate water quality goals may benefit from a consideration of these contextual and cultural differences.


2019 ◽  
Vol 62 (3) ◽  
pp. 92-96
Author(s):  
Wendy Pons ◽  
Andria Jones-Bitton ◽  
Steven Lam ◽  
Scott A. McEwen ◽  
Katarina Pintar ◽  
...  

Public health inspectors (PHIs) play an important role in enforcing the regulation and monitoring of approximately 9000 small noncommunity drinking water systems across Ontario. These small drinking water systems (SDWS) are diverse and face unique challenges. The purpose of this research was to explore PHIs’ insights and needs related to these SDWS in Ontario, Canada, to inform future policy and training initiatives to support safe drinking water. Data were collected through teleconference-conducted focus groups. Transcripts were analyzed and three major themes were found: the operator–PHI relationship, PHI training and information needs, and operational challenges. Overall, participants reported that they felt confident in their ability to inspect SDWSs. Main concerns to water safety were the technical ability of the water operator to manage their water supply and the impact of having a long time period between inspections of water systems. Future research should explore the cost-benefit of increasing inspection frequency in SDWSs and a variety of training and education initiatives for PHIs and operators of SDWSs.


ACS Omega ◽  
2018 ◽  
Vol 3 (11) ◽  
pp. 14824-14832 ◽  
Author(s):  
Yaohuan Gao ◽  
Benjamin F. Trueman ◽  
Amina K. Stoddart ◽  
Graham A. Gagnon

Author(s):  
Gabriel Pablo Lobo ◽  
Ashok Gadgil

Toxic levels of lead leaching from ageing water distribution infrastructure affect over 5,000 public drinking water systems in the US. Pipe replacement, the most effective solution to this problem, is...


Author(s):  
Francesca Serio ◽  
Lucia Martella ◽  
Giovanni Imbriani ◽  
Adele Idolo ◽  
Francesco Bagordo ◽  
...  

Background: The quality of water for human consumption is an objective of fundamental importance for the defense of public health. Since the management of networks involves many problems of control and efficiency of distribution, the Water Safety Plan (WSP) was introduced to address these growing problems. Methods: WSP was applied to three companies in which the water resource assumes central importance: five water kiosks, a third-range vegetable processing company, and a residence and care institution. In drafting the plan, the terms and procedures designed and tested for the management of urban distribution systems were applied to safeguard the resource over time. Results: The case studies demonstrated the reliability of the application of the model even to small drinking-water systems, even though it involved a greater effort in analyzing the incoming water, the local intended use, and the possibilities for managing the containment of the dangers to which it is exposed. This approach demonstrates concrete effectiveness in identifying and mitigating the dangers of altering the quality of water. Conclusions: Thanks to the WSP applied to small drinking-water systems, we can move from management that is focused mainly on verifying the conformity of the finished product to the creation of a global risk assessment and management system that covers the entire water supply chain.


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