scholarly journals Incorporation of the Multiple Barrier Approach in drinking water risk assessment tools

2010 ◽  
Vol 9 (2) ◽  
pp. 349-360 ◽  
Author(s):  
Ian Michael Summerscales ◽  
Edward A. McBean
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Water Contamination ◽  
Disease Outbreaks ◽  
Assessment Tools ◽  
Water Safety ◽  
Drinking Water Contamination ◽  
Drinking Water Safety ◽  
Risk Assessment Tools ◽  
Developed Nations

A number of existing risk assessment tools make reference to, or incorporate, a Multiple Barrier Approach to drinking water safety. Three waterborne disease outbreaks that occurred in developed nations were used as case studies to test a selected set of risk assessment tools. The outbreaks were used to determine how well the risk assessment tools identify hazards and vulnerabilities associated with different barriers to drinking water contamination.

Evaluation of Risk Assessment Tools to Predict Canadian Waterborne Disease Outbreaks

2010 ◽  
Vol 45 (1) ◽  
pp. 1-11
Author(s):  
Ian Michael Summerscales ◽  
Edward A. McBean
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Disease Outbreaks ◽  
Water Quality Monitoring ◽  
Water Systems ◽  
Assessment Tools ◽  
Water Safety ◽  
Waterborne Disease ◽  
Drinking Water Contamination ◽  
Risk Assessment Tools

Abstract A number of risk assessment tools and guidance documents have been developed by regulatory and nongovernmental bodies to enable risk assessment of drinking water systems. To evaluate the strengths and weaknesses of available risk assessment tools, three of the existing risk assessment tools were applied to waterborne disease outbreaks in North Battleford, Saskatchewan, and Walkerton, Ontario, to determine whether the risk assessment tools would have indicated that the water systems were at risk of failure. Both of these outbreaks are sufficiently well documented to allow testing of the risk assessment tools. Both of the outbreaks occurred partly due to vulnerabilities that prevented the respective water systems from having effective multiple barriers to drinking water contamination. The risk assessment tools generally identified the hazards that resulted in contamination of the source water. However, the different tools had different levels of success in identifying vulnerabilities in the downstream barriers such as treatment processes and water quality monitoring activities. None of the risk assessment tools successfully incorporated the interdependent nature of the multiple barriers of drinking water safety.

Drinking water contamination in Walkerton, Ontario: positive resolutions from a tragic event

2003 ◽  
Vol 47 (3) ◽  
pp. 1-6 ◽  
Author(s):  
R. Holme
Keyword(s):  
Drinking Water ◽  
Water Contamination ◽  
Provincial Government ◽  
Regulatory Body ◽  
Water Protection ◽  
Water Safety ◽  
Drinking Water Contamination ◽  
Drinking Water Safety ◽  
Tragic Event ◽  
Set Up

In May 2000, Escherichia coli 0157:H7 and Campylobacter jejuni contaminated the drinking water supply in Walkerton, Ontario. Seven people died and over 2,000 were ill as a result. The Ontario Provincial Government set up a judicial Inquiry into the circumstances surrounding the outbreak and also moved quickly to introduce a new Drinking Water Regulation that incorporated some significant requirements for drinking water providers. The Inquiry itself was in three parts: (a) part 1 related to the events that occurred in Walkerton and why the water contamination occurred; (b) part 1A related specifically to the role of the Provincial Government in the event; and (c) part 2 related to the future of drinking water safety in Ontario with potential to influence regulation on a wider basis. A number of other actions were taken after Walkerton. In August 2000, the Ontario Government, through the Regulatory body, the Ontario Ministry of the Environment (MOE) (a) re-issued and revised the Ontario Drinking Water Objectives (ODWO) as the Ontario Drinking Water Standards (ODWS) and (b) introduced new regulations governing drinking water in Ontario - the Ontario Drinking Water Protection Regulation. One of the key features of the Drinking Water Protection Regulation was the requirement to produce an independent Engineers’ Report on all water systems. This paper provides a unique perspective on the Walkerton tragedy and its aftermath. The author was active in many aspects of the resulting activity (Chair of the Ontario Water Works Association's (a section of the AWWA) Special Committee involved in Part 2 of the Walkerton Inquiry; author of several of the Engineers’ Reports mandated by Regulation; reviewer on behalf of the Regulator of Engineers' Reports submitted by others). The Engineers’ Reports were of interest because (1) the drinking water providers (mostly municipalities) were mandated by regulation to complete the Reports by specific dates and are paying for the Reports, (2) the work had to be done by a registered professional engineer who is not an employee of the owner or the operator if a different entity and (3) the engineer had to sign a declaration that the Regulator could rely on the accuracy of the Report. In other words, the Municipality retained the Engineer and paid them to produce the Report - the Engineer essentially carried the liability while the Regulator had the final say in the acceptability of the Report, a sort of eternal triangle of responsibilities. The paper will outline how the drinking water profession in North America worked together to provide the Walkerton Inquiry with the benefit of its experience and knowledge of best practices to the benefit of consumers and the drinking water providers. It will also outline the procedures adopted to produce the independent Engineers’ Reports and how the findings are being applied to further improve drinking water safety in Ontario, across Canada and in similar situations around the world.

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.

scholarly journals Health Risk Assessment on Rural Drinking Water Safety —A Case Study in Rain City District of Ya’an City of Sichuan Province

2009 ◽  
Vol 01 (02) ◽  
pp. 128-135 ◽  
Author(s):  
Fuquan NI ◽  
Guodong LIU ◽  
Huazhun REN ◽  
Shangchuan YANG ◽  
Jian YE ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Health Risk ◽  
Health Risk Assessment ◽  
Sichuan Province ◽  
Water Safety ◽  
Drinking Water Safety ◽  
City District

scholarly journals Drinking-water safety – challenges for community-managed systems

2008 ◽  
Vol 6 (S1) ◽  
pp. 33-41 ◽  
Author(s):  
S. Rizak ◽  
Steve E. Hrudey
Keyword(s):  
Risk Factors ◽  
Drinking Water ◽  
Failure Modes ◽  
Water System ◽  
Disease Outbreaks ◽  
Warning Signs ◽  
Water Safety ◽  
Waterborne Disease ◽  
Drinking Water Safety ◽  
Weather Events

A targeted review of documented waterborne disease outbreaks over the past decades reveals some recurring themes that should be understood by drinking-water suppliers. Evidence indicates the outbreaks are often linked to some significant change in conditions that provides a sudden challenge to a water system. Severe weather events, such as heavy rainfall or runoff from snow melt, as well as treatment process and system changes, are common risk factors for drinking-water outbreaks. Failure to recognise warning signs and complacency are important contributors to drinking water becoming unsafe. Drinking-water suppliers must focus on competence and vigilance in maintaining effective multiple barriers appropriate to the challenges facing the drinking-water system. Understanding the risk factors and failure modes of waterborne disease outbreaks is an essential component for effective management of community drinking-water supplies and ensuring the delivery of safe drinking-water to consumers.

Toxicologic Risk Assessment Issues for Drinking Water Safety

1992 ◽  
Vol 11 (3) ◽  
pp. 311-319
Author(s):  
Richard D. Thomas
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
National Research Council ◽  
Chemical Exposure ◽  
Epidemiologic Studies ◽  
Current View ◽  
Water Safety ◽  
Drinking Water Safety ◽  
Assessment Procedures ◽  
A Current

The intent of this presentation is to review the studies conducted by the National Research Council (NRC) where risk assessment was the central theme and to present both a current view and some ideas for the future of risk assessment procedures for drinking water. Although the principal interest is in the use of toxicologic data in assessing risk, nonetheless, mention is made of the use of epidemiologic studies and other types of research investigations that may produce useful information for estimating risk to humans from chemical exposure.

scholarly journals How can the UK statutory Cryptosporidium monitoring be used for Quantitative Risk Assessment of Cryptosporidium in drinking water?

2007 ◽  
Vol 5 (S1) ◽  
pp. 107-118 ◽  
Author(s):  
P. W. M. H. Smeets ◽  
J. C. van Dijk ◽  
G. Stanfield ◽  
L. C. Rietveld ◽  
G. J. Medema
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
State Of The Art ◽  
Quantitative Risk Assessment ◽  
Source Water ◽  
Water Safety ◽  
Drinking Water Safety ◽  
Full Benefit ◽  
The Uk ◽  
Treated Drinking Water

Quantitative Microbiological Risk Assessment (QMRA) is increasingly being used to complement traditional verification of drinking water safety through the absence of indicator bacteria. However, the full benefit of QMRA is often not achieved because of a lack of appropriate data on the fate and behaviour of pathogens. In the UK, statutory monitoring for Cryptosporidium has provided a unique dataset of pathogens directly measured in large volumes of treated drinking water. Using this data a QMRA was performed to determine the benefits and limitations of such state-of-the-art monitoring for risk assessment. Estimates of the risk of infection at the 216 assessed treatment sites ranged from 10−6.5 to 10−2.5 person−1 d−1. In addition, Cryptosporidium monitoring data in source water was collected at eight treatment sites to determine how Cryptosporidium removal could be quantified for QMRA purposes. Cryptosporidium removal varied from 1.8 to 5.2 log units and appeared to be related to source water Cryptosporidium concentration. Application of general removal credits can either over- or underestimate Cryptosporidium removal by full-scale sedimentation and filtration. State-of-the-art pathogen monitoring can identify poorly performing systems, although it is ineffective to verify drinking water safety to the level of 10-4 infections person−1 yr−1.

Integrated risk assessment and screening analysis of drinking water safety of a conventional water supply system

2007 ◽  
Vol 56 (6) ◽  
pp. 47-56 ◽  
Author(s):  
F. Sun ◽  
J. Chen ◽  
Q. Tong ◽  
S. Zeng
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Water Supply ◽  
Supply System ◽  
Water Supply System ◽  
Water Supply Systems ◽  
Assessment Procedure ◽  
Water Safety ◽  
Screening Analysis ◽  
Drinking Water Safety

Management of drinking water safety is changing towards an integrated risk assessment and risk management approach that includes all processes in a water supply system from catchment to consumers. However, given the large number of water supply systems in China and the cost of implementing such a risk assessment procedure, there is a necessity to first conduct a strategic screening analysis at a national level. An integrated methodology of risk assessment and screening analysis is thus proposed to evaluate drinking water safety of a conventional water supply system. The violation probability, indicating drinking water safety, is estimated at different locations of a water supply system in terms of permanganate index, ammonia nitrogen, turbidity, residual chlorine and trihalomethanes. Critical parameters with respect to drinking water safety are then identified, based on which an index system is developed to prioritize conventional water supply systems in implementing a detailed risk assessment procedure. The evaluation results are represented as graphic check matrices for the concerned hazards in drinking water, from which the vulnerability of a conventional water supply system is characterized.

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