scholarly journals Evaluation of Residual Disinfectant Levels in Public Drinking Water Distribution Systems in Relation to an Acanthamoeba Keratitis Outbreak - Illinois, 2002-2009

2021 ◽  
Author(s):  
Hannah Holsinger ◽  
Anna Blackstock ◽  
Sharon L. Roy ◽  
Susan Shaw
Keyword(s):  
Drinking Water ◽  
Environmental Protection Agency ◽  
Multiple Testing ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water System ◽  
Acanthamoeba Keratitis ◽  
Cook County ◽  
Entire Study ◽  
Corneal Injury

Acanthamoeba keratitis (AK) is a painful, potentially blinding eye disease associated with contact lens use and corneal injury. AK, caused by the free-living amoeba Acanthamoeba, is ubiquitous in the environment and has been isolated from municipal water supplies. It can be tolerant of normal chlorine levels in drinking water. An AK outbreak investigated in 2003-2005 in five Illinois counties showed a lower AK age-standardized rate ratio in Cook County than in surrounding counties and was hypothesized to be due in part to reductions in residual disinfectant levels (RDLs) in drinking water. We evaluated RDLs in public water systems in the same five Illinois counties over eight years (2002-2009) using a multivariable model of water system RDL measurements. Fitted RDLs for each county were in the acceptable range by United States Environmental Protection Agency standards for the entire study period. After correcting for multiple testing, two of the surrounding counties had fitted RDLs that differed from Cook County for one year. This pattern differed from the epidemiologic pattern of cases observed in the AK outbreak. Our findings do not support the hypothesis that the development of AK was associated with changes in RDLs in the five Illinois counties.

scholarly journals Quantitative microbial risk assessment of distributed drinking water using faecal indicator incidence and concentrations

2007 ◽  
Vol 5 (S1) ◽  
pp. 131-149 ◽  
Author(s):  
J. Hein M. van Lieverloo ◽  
E. J. Mirjam Blokker ◽  
Gertjan Medema
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water System ◽  
Quantitative Microbial Risk Assessment ◽  
Concentration Data ◽  
Faecal Contamination ◽  
Microbial Risk ◽  
Contamination Events ◽  
Very High

Quantitative Microbial Risk Assessments (QMRA) have focused on drinking water system components upstream of distribution to customers, for nominal and event conditions. Yet some 15—33% of waterborne outbreaks are reported to be caused by contamination events in distribution systems. In the majority of these cases and probably in all non-outbreak contamination events, no pathogen concentration data was available. Faecal contamination events are usually detected or confirmed by the presence of E.coli or other faecal indicators, although the absence of this indicator is no guarantee of the absence of faecal pathogens. In this paper, the incidence and concentrations of various coliforms and sources of faecal contamination were used to estimate the possible concentrations of faecal pathogens and consequently the infection risks to consumers in event-affected areas. The results indicate that the infection risks may be very high, especially from Campylobacter and enteroviruses, but also that the uncertainties are very high. The high variability of pathogen to thermotolerant coliform ratios estimated in environmental samples severely limits the applicability of the approach described. Importantly, the highest ratios of enteroviruses to thermotolerant coliform were suggested from soil and shallow groundwaters, the most likely sources of faecal contamination that are detected in distribution systems. Epidemiological evaluations of non-outbreak faecal contamination of drinking water distribution systems and thorough tracking and characterisation of the contamination sources are necessary to assess the actual risks of these events.

scholarly journals Persistence of Nontuberculous Mycobacteria in a Drinking Water System after Addition of Filtration Treatment

2006 ◽  
Vol 72 (9) ◽  
pp. 5864-5869 ◽  
Author(s):  
Elizabeth D. Hilborn ◽  
Terry C. Covert ◽  
Mitchell A. Yakrus ◽  
Stephanie I. Harris ◽  
Sandra F. Donnelly ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Cold Water ◽  
Nontuberculous Mycobacteria ◽  
Treatment Plant ◽  
Water System ◽  
Drinking Water Treatment ◽  
Drinking Water System

ABSTRACT There is evidence that drinking water may be a source of infections with pathogenic nontuberculous mycobacteria (NTM) in humans. One method by which NTM are believed to enter drinking water distribution systems is by their intracellular colonization of protozoa. Our goal was to determine whether we could detect a reduction in the prevalence of NTM recovered from an unfiltered surface drinking water system after the addition of ozonation and filtration treatment and to characterize NTM isolates by using molecular methods. We sampled water from two initially unfiltered surface drinking water treatment plants over a 29-month period. One plant received the addition of filtration and ozonation after 6 months of sampling. Sample sites included those at treatment plant effluents, distributed water, and cold water taps (point-of-use [POU] sites) in public or commercial buildings located within each distribution system. NTM were recovered from 27% of the sites. POU sites yielded the majority of NTM, with >50% recovery despite the addition of ozonation and filtration. Closely related electrophoretic groups of Mycobacterium avium were found to persist at POU sites for up to 26 months. Water collected from POU cold water outlets was persistently colonized with NTM despite the addition of ozonation and filtration to a drinking water system. This suggests that cold water POU outlets need to be considered as a potential source of chronic human exposure to NTM.

Utility quick test for analyzing materials for drinking water distribution systems for effect on taste-and-odor

2004 ◽  
Vol 49 (9) ◽  
pp. 75-80 ◽  
Author(s):  
L. Schweitzer ◽  
P. Tomboulian ◽  
K. Atasi ◽  
T. Chen ◽  
D. Khiari
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Profile Analysis ◽  
Water System ◽  
Drinking Water Distribution Systems ◽  
Taste And Odor ◽  
Drinking Water Distribution ◽  
Sensory Analyses ◽  
European Standards

A workshop of international drinking water experts was convened in Sedona, Arizona, March 26-27, 2001 for the purpose of developing a method for testing drinking water system components for their potential to contribute to taste-and-odor problems in drinking water. The workshop participants derived a method using provisions from European Standards as well as newly developed approaches. It is intended that this method can serve as a temporary procedure for water utilities, as well as a recommended template to derive an official standard. Materials to be tested may include pipes, fittings, ancillaries, joints, lubricants, tanks, and reservoirs. The recommended method includes a migration (leaching) test with chlorinated water, followed by sensory analysis of the samples from the migration test after dechlorination. Sensory analyses use both statistical (e.g., triangle test) and descriptive (e.g. Flavor Profile Analysis) techniques. A decision tree for the results is provided.

Materials used in drinking water distribution systems: contribution to taste-and-odor

2004 ◽  
Vol 49 (9) ◽  
pp. 219-226 ◽  
Author(s):  
P. Tomboulian ◽  
L. Schweitzer ◽  
K. Mullin ◽  
J. Wilson ◽  
D. Khiari
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water System ◽  
Water Utilities ◽  
Drinking Water Distribution Systems ◽  
Taste And Odor ◽  
Drinking Water Distribution ◽  
Materials Used ◽  
Water Taste

In order to assist drinking water utilities with identifying the possible sources and causes of taste-and-odor conditions associated with materials used in distribution systems, we evaluated information from case studies and a database from the National Sanitation Foundation (NSF), International. This database identified chemicals that had leached from drinking water system components during testing of materials under ANSI/NSF Standard 61, which provides information to water utilities on potential taste-and-odor and health concerns from the use of new materials. The data were arranged to provide a process for locating the potential source of a taste-and-odor event. After a sensory analysis is conducted on the drinking water samples, the descriptor can be matched with categories on the "Drinking Water Taste and Odor Wheel 2000" in order to suggest the candidate material.

The assessment of biofilm community composition on plumbing materials in filtered and unfiltered water distribution systems

2003 ◽  
Vol 3 (1-2) ◽  
pp. 187-191
Author(s):  
M.M. Critchley ◽  
N.J. Cromar ◽  
H.J. Fallowfield
Keyword(s):  
Drinking Water ◽  
Fatty Acid ◽  
Community Composition ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Polymer Materials ◽  
Fatty Acid Profiles ◽  
Water Supplies ◽  
Drinking Water Distribution Systems

Biofilms have been extensively characterised within drinking water distribution systems. However, the significance of materials on biofilm species diversity is not established. This study investigated the community composition of biofilms on plumbing materials receiving filtered and unfiltered water supplies. Biofilms were extracted from polybutylene, polyethylene, cross-linked polyethylene, unplasticised polyvinyl chloride and copper tubes in sampling rigs receiving Murray-Onkaparinga water before or after filtration. Biofilms were extracted and analysed for fatty acid composition using the FAME™ methodology. There were differences in the fatty acid profiles of biofilms and the respective water supplies, indicating differences in the attached and planktonic communities. The results also showed significant differences in the fatty acid profiles of biofilms on the polymer materials compared to copper, suggesting variations in biofilm populations on the different materials. The potential for materials to select for microbial populations has significant implications for the ecology of drinking water biofilms.

scholarly journals Identification of Aminoglycoside Resistance Genes From Bacteria Isolated From Selected Municipal Drinking Water Distribution Systems in Southwestern Nigeria

2020 ◽  
Vol 41 (S1) ◽  
pp. s255-s255
Author(s):  
Ayodele T. Adesoji ◽  
Adeniyi A. Ogunjobi
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Southwestern Nigeria ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution

Background: Multidrug-resistant bacteria can lead to treatment failure, resulting in infectious diseases being transferred through nonpotable water. Aminoglycosides are an important class of antibiotics that are abused in Nigeria. Few studies have investigated aminoglycoside-modifying genes (AMGs) that are likely responsible for resistance in Nigeria bacteria isolates. Therefore, we aimed to characterize AMGs from isolates in drinking water distribution systems (DWDS) in southwestern Nigeria. Methods: Multidrug-resistant bacteria (n = 181) that had been previously characterized by 16S rDNA sequencing and that were positive for resistance to at least 1 aminoglycoside antibiotic were selected from 6 treated and untreated water distribution systems. Strains were PCR genotyped for 3 AMGs: aph(3)c, ant(3)b and aph(6)-1dd. Results: Of 181 MDR bacteria tested, 69 (38.12%) were positive for at least 1 of the AMGs. The most common was ant(3)c (27.6%), followed by aph(3")c (18.23%). Both aph(3)c and ant(3")b were found in 7.73% of tested isolates, ant(3)b was most commonly found in Alcaligenes spp (50%). Furthermore, aph(3")c was most commonly detected in Proteus spp (50%). Other genera positive for AMGs included Acinetobacter, Aeromonas, Bordetella, Brevundimonas, Chromobacterium, Klebsiella, Leucobacter, Morganella, Pantoae, Proteus, Providencia, Psychrobacter, and Serratia. Conclusions: High occurrence of ant(3)c and aph(3)c among these bacteria call for urgent attention among public health workers because these genes can be easily disseminated to consumers if present on mobile genetic elements like plasmids, integrons, and transposons.Funding: NoneDisclosures: None

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