scholarly journals Modification of the H2S test to screen for the detection of sulphur- and sulphate-reducing bacteria of faecal origin in water

2020 ◽  
Author(s):  
Bastian Schnabel ◽  
Jonathan Lance Caplin ◽  
Ian Richard Cooper
Keyword(s):  
Drinking Water ◽  
Sensitivity And Specificity ◽  
Detection Threshold ◽  
Penicillin G ◽  
Water Safety ◽  
Low Resource Settings ◽  
E Coli ◽  
Low Resource ◽  
Drinking Water Safety ◽  
Drinking Water Analysis

Abstract The H2S test was created to assess the microbial quality of drinking water in low-resource settings, but the original version of the H2S test lacks sensitivity and specificity for faecal indicator bacteria. There is evidence that a modified media formula of the H2S test may be more sensitive and specific for the faecal indicator bacterium Escherichia coli (E. coli) and less sensitive to organisms of non-faecal origin. This research established the detection threshold and operational range of the H2S test, to increase its sensitivity and specificity for E. coli. A total of 20 modifications of the H2S test, and the original test, were assayed against 20 confirmed and pure culture bacteria of faecal and non-faecal origin at varying concentrations. Additionally, some of the H2S test modifications were evaluated against standard methods for drinking-water analysis. Results indicate that using a modified version of the H2S test containing L-cystine and 2-mercaptopyridine, and bile salts or penicillin G, E. coli will produce H2S. In addition, this research reveals which organisms react positively to the original and modified versions of the H2S test. The modified versions of the H2S test can be promoted as a simple screening test for microbial drinking-water safety in low-resource settings.

Pathogens

High and Dry ◽  
2017 ◽  
Author(s):  
William M. Alley ◽  
Rosemarie Alley
Keyword(s):  
Drinking Water ◽  
Case Studies ◽  
Source Water ◽  
Water Protection ◽  
Water Safety ◽  
E Coli ◽  
Drinking Water Safety ◽  
Source Water Protection ◽  
Canadian Provinces

This chapter examines microbial contamination of groundwater that can threaten drinking water supplies and the importance of proper well construction and protection. Case studies are presented of E. coli poisoning in Walkerton, Ontario and viruses in Wisconsin. The Walkerton incident in 2000 caused Canadian provinces to take a hard look at their drinking water safety through better monitoring, enforcement, training, and source-water protection programs. The Wisconsin case study illustrates the potential for viruses from leaking sewers to contaminant municipal wells.

scholarly journals Risk assessment of drinking water from public wells

2017 ◽  
Vol 70 (9-10) ◽  
pp. 297-306
Author(s):  
Sanja Bijelovic ◽  
Marija Jevtic ◽  
Natasa Dragic ◽  
Emil Zivadinovic ◽  
Danijela Lukic ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Human Health ◽  
National Standards ◽  
Management Approach ◽  
Water Safety ◽  
Drinking Water Safety ◽  
The Republic ◽  
Drinking Water Analysis ◽  
Hazard Rating

Introduction. The safety of drinking water should be considered in the context of managing the risk from hazards that may compromise it. The aim of this study was to identify microbiological, chemical and physical hazards of drinking water from public wells which may impact human health, and to evaluate the results of routine drinking water analysis, not taking into account the national legislation, but the risk management approach. Material and Methods. Drinking water was sampled from 20 public wells in South Backa District and analyzed at the Institute of Public Health of Vojvodina according to accredited national standards during 2016. The drinking water hazards were defined according to international recommendations. Risk assessment was done using a semiquantitative approach, which assesses the like?lihood and consequences of a hazard, rating the risks as low, medium, high and very high. Results. Of 218 drinking water samples, according to national regulations, only 10% were healthy for consumption. The recognized hazards were thermotolerant coliforms (especially Escherichia coli), enterococci (genus Streptococcus), Pseudomonas aeruginosa, Proteus species and nitrates above legal limits. The risk was rated high, with an impact on the morbidity of sensitive populations in 2/3 of controlled public wells, in 1/3 as medium, leading to abandonment of drinking water sources. Conclusion. The proposed risk assessment methodology is a tool that provides easily understandable and clear information on the possibility of using public wells with a consequent impact on human health. The management of drinking water safety is the greatest challenge, systematically prioritizing risk assessment of drinking water from public wells for the health of the population in the Republic of Serbia.

Hygienic Evaluation of Reclaimed Water Used to Irrigate Food Crops—A Case Study

1999 ◽  
Vol 40 (4-5) ◽  
pp. 261-267 ◽  
Author(s):  
B. Sheikh ◽  
R. C. Cooper ◽  
K. E. Israel
Keyword(s):  
Drinking Water ◽  
Food Safety ◽  
Municipal Wastewater ◽  
Pilot Project ◽  
Secondary Effluent ◽  
Food Crops ◽  
Water Safety ◽  
Recycled Water ◽  
E Coli ◽  
Drinking Water Safety

The study was designed to test the continued validity of a field pilot project (completed in 1987) that had found irrigation of food crops with tertiary-treated reclaimed municipal wastewater to be safe. It was also designed to determine whether or not pathogenic microorganisms of concern to food safety, such as E. coli 0157:H7, Cyclospora, enteric viruses and Salmonella were present in disinfected tertiary recycled water. Sampling of the tertiary water was conducted at intervals over a period of three months. In addition, at the same time, samples were taken from the raw incoming wastewater, from secondary effluent, and from a control source, local well water. The results from samples of recycled water are comparable to similar tests at other well-operated, tertiary recycled water treatment plants and compare well with sources of drinking water supply. Other parasites, of lesser concern to food safety than to drinking water safety, were either absent or were detected at extremely low concentrations of empty, non-viable cysts. The Tertiary Water Food Safety Study did not detect any Salmonella, Cyclospora and E. coli 0157:H7 in any of the samples of tertiary recycled water from the Monterey Country Water Recycling Projects (MCWRP).

Study on Mechanism Design of Rural Drinking Water Safety Engineering Project Financing Guarantee

2013 ◽  
Vol 361-363 ◽  
pp. 674-681
Author(s):  
Wei Li
Keyword(s):  
Drinking Water ◽  
Mechanism Design ◽  
Safety Engineering ◽  
Project Financing ◽  
Water Safety ◽  
Public Fund ◽  
Engineering Project ◽  
Drinking Water Safety ◽  
Project Construction ◽  
Set Up

As more and more non-public fund entering rural drinking water safety engineering project market; it becomes very necessary to built rural drinking water safety engineering project guarantee mechanism. This paper proposes three steps of mechanism design. Firstly, history data is used to fit multivariate linear equation set up describing relationship between bank loss and key risk factors. Secondly, guarantee fee is calculated through model regression, which is threefold of possible bank loss. Thirdly, guarantee fee is adjusted according to variety of key risk factor in the process of project construction and operating.

Implementation of Alberta's drinking water safety plans

2013 ◽  
Vol 49 (1) ◽  
pp. 5-9 ◽  
Author(s):  
D. C. Reid ◽  
K. Abramowski ◽  
A. Beier ◽  
A. Janzen ◽  
D. Lok ◽  
...  
Keyword(s):  
Drinking Water ◽  
Effective Action ◽  
Main Element ◽  
Quality And Safety ◽  
Biological Parameters ◽  
Water Safety ◽  
Drinking Water Safety ◽  
Regulatory Approach ◽  
Water Safety Plans ◽  
Safety Of Drinking Water

Traditionally, the regulatory approach to maintaining the quality and safety of drinking water has largely been a prescriptive one based on the ability of any given supply to meet standards set for a number of different chemical and biological parameters. There are a number of issues around the assumptions and the limitations of a sampling and analysis regime. The basis for such regimes is essentially reactive rather than proactive and, consequently, the cause of the concern may already have impacted consumers before any effective action can be taken. Environment and Sustainable Resource Development has developed a template for recording drinking water safety plans together with guidance notes to help complete them. The template has been developed in MS-Excel and has been designed in a straightforward step-wise manner with guidance on the completion of each sheet. It includes four main risk tables covering each main element of water supply which are pre-populated with commonly found ‘generic’ risks and these are carefully assessed before considering what action is required to deal with significant risks. Following completion of the risk tables, key risks are identified and the interventions required to bring them into control.

A fatal waterborne disease epidemic in Walkerton, Ontario: comparison with other waterborne outbreaks in the developed world

2003 ◽  
Vol 47 (3) ◽  
pp. 7-14 ◽  
Author(s):  
S.E. Hrudey ◽  
P. Payment ◽  
P.M. Huck ◽  
R.W. Gillham ◽  
E.J. Hrudey
Keyword(s):  
Drinking Water ◽  
Water Security ◽  
Reference Source ◽  
Water Safety ◽  
Drinking Water Safety ◽  
Public Inquiry ◽  
Contaminated Drinking Water ◽  
The Government ◽  
Safety Of Drinking Water ◽  
Developed World

An estimated 2,300 people became seriously ill and seven died from exposure to microbially contaminated drinking water in the town of Walkerton, Ontario, Canada in May 2000. The severity of this drinking water disaster resulted in the Government of Ontario calling a public inquiry by Mr. Justice Dennis O’Connor to address the cause of the outbreak, the role (if any) of government policies in contributing to this outbreak and, ultimately, the implications of this experience on the safety of drinking water across the Province of Ontario. The circumstances surrounding the Walkerton tragedy are an important reference source for those concerned with providing safe drinking water. Although some circumstances are obviously specific to this epidemic, others are uncomfortably reminiscent of waterborne outbreaks that have occurred elsewhere. These recurring themes suggested the need for attention to broad issues of drinking water security and they present the challenge for how drinking water safety can be managed to prevent such tragedies in the future.

Rapid drinking water safety estimation in cities: Piloting a globally scalable method in Cochabamba, Bolivia

2019 ◽  
Vol 654 ◽  
pp. 1132-1145 ◽  
Author(s):  
Lucas Rocha-Melogno ◽  
Rebecca Yoo ◽  
Osvaldo Broesicke ◽  
Achilles Kallergis ◽  
José Garcia ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Safety ◽  
Drinking Water Safety ◽  
Safety Estimation

scholarly journals One-step removal of lead from water using an electricity-free and sustainable membrane filtration

2021 ◽  
Vol 27 (4) ◽  
pp. 166-172
Author(s):  
Junwei Zhang ◽  
Yan Tung Lo ◽  
Hao Guo ◽  
Chuyang Tang
Keyword(s):  
Drinking Water ◽  
Removal Efficiency ◽  
Membrane Filtration ◽  
High Water ◽  
Water Safety ◽  
Drinking Water Contamination ◽  
Emergency Situations ◽  
Drinking Water Safety ◽  
Effective Removal ◽  
Volumetric Loading

Lead (Pb) is a typical contaminant in water with adverse effects on human health. Hong Kong’s incident of drinking water contamination by Pb in 2015 caused severe public concerns regarding drinking water safety. Conventional treatment methods for Pb removal generally require electricity, chemical dosage, and considerable time and space, which significantly restrict their use for rapid water purification under emergency situations. In this study, a polyvinyl alcohol/polyacrylic acid (PVA/PAA) composite nanofibrous membrane was developed for the rapid and effective removal of Pb from water. The PVA/PAA membrane had a high water permeability of 550 L/m2/h/kPa - 710 L/m2/h/kPa, which allowed the filtration to be driven by gravity (e.g. with a water height of 10.0 cm). The membrane showed consistently high removal efficiency of Pb (> 95%) with a volumetric loading up to 3000 L/m2. This high removal efficiency was attributed to the combined effects of complexing and electrostatic attraction between Pb and PAA. An esculent citric acid was used to regenerate the exhausted PVA/PAA membrane. The regenerated membrane maintained its removal efficiency of Pb over a five-cycle filtration. These results imply that the PVA/PAA composite membrane can be repeatedly used in electricity-free filtration devices for rapid elimination of Pb under emergency situations.

Off-flavor as the consumer's measure of drinking water safety

1995 ◽  
Vol 31 (11) ◽  
pp. 1-8 ◽  
Author(s):  
Michael J. McGuire
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Utilities ◽  
Regulatory Environment ◽  
Safe Drinking Water ◽  
Water Safety ◽  
Safe Water ◽  
Drinking Water Safety ◽  
Off Flavors ◽  
Health Related

If consumers detect an off-flavor in their drinking water, they are likely to believe that it probably is not safe. Water utilities will be defeating their best efforts to provide safe drinking water if they only meet health-related regulations and do not provide water that is free of off-flavor problems. The purpose of this paper is to explore the current U.S. regulatory environment and discuss how these regulations can adversely impact the control of off-flavors in drinking water. Utilities should adopt a water quality goal that allows them to not only meet the minimums of the regulations, but also meet the customer's highest standards - water that is free of off-flavors.

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